Issue 16951: Time point subdivision is out of place twice (date-time-ftf)
Source: NIST (Mr. Edward J. Barkmeyer, edbark(at)nist.gov)
Nature: Uncategorized Issue
Severity: 
Summary: At the end of section 9.3 the fact type 'finite time scale subdivides time point' is defined and depicted in Figure 9-6.  This fact type is a commonly used property of finite time scales, and is not specific to individual time points.  That is, the finite time scale day-of-hours subdivides every day-of-month, for example.  So the text and diagram should be at the end of 9.2, where finite time scale is defined.  


Also, diagram 9-6 does not show the operations on time point and finite time scale that are associated with this fact type and shown in diagram 12-12.


Finally, diagram 12-12 (section 12.4) shows this fact type as well, but section 12.4 never uses it, and diagram 12-12 shows a <<specialization>> relationship that is never discussed anywhere in the text.  If the relationship is important, it should be discussed.  Otherwise, the subdivision association is out of place in diagram 12-12 and the "specialization" dependency should be deleted from the UML model.


Recommendation:


Move the diagram and text for 'finite time scale subdivides time point' to the end of 9.2, include the operations on the diagram.  Delete the fact type from diagram 12-12, and delete the "specialization" dependency altogether.



Resolution: 
Revised Text: 
Actions taken:
January 10, 2012: received issue
Discussion: 

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Specification:  Date Time Vocabulary
Version:  beta-1
Title:  Time point subdivision is out of place twice
Source:  Ed Barkmeyer, NIST, edbark@nist.gov'


Summary:


At the end of section 9.3 the fact type 'finite time scale subdivides time point' is defined and depicted in Figure 9-6.  This fact type is a commonly used property of finite time scales, and is not specific to individual time points.  That is, the finite time scale day-of-hours subdivides every day-of-month, for example.  So the text and diagram should be at the end of 9.2, where finite time scale is defined.  


Also, diagram 9-6 does not show the operations on time point and finite time scale that are associated with this fact type and shown in diagram 12-12.


Finally, diagram 12-12 (section 12.4) shows this fact type as well, but section 12.4 never uses it, and diagram 12-12 shows a <<specialization>> relationship that is never discussed anywhere in the text.  If the relationship is important, it should be discussed.  Otherwise, the subdivision association is out of place in diagram 12-12 and the "specialization" dependency should be deleted from the UML model.


Recommendation:


Move the diagram and text for 'finite time scale subdivides time point' to the end of 9.2, include the operations on the diagram.  Delete the fact type from diagram 12-12, and delete the "specialization" dependency altogether.



-- 
Edward J. Barkmeyer                        Email: edbark@nist.gov
National Institute of Standards & Technology
Manufacturing Systems Integration Division
100 Bureau Drive, Stop 8263                Tel: +1 301-975-3528
Gaithersburg, MD 20899-8263                Cel: +1 240-672-5800


Date: Tue, 13 Mar 2012 12:34:56 -0400
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Subject: Re: Issue 16951 -- time point subdivision - revised draft resolution
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Observing that all the uses of 'finite time scale subdivides time point' are about generating the component time points, not the time intervals, I revised the definition in the attached draft (d2).


-Ed



Ed Barkmeyer wrote:
See attached.


I noted that the text of clause 12.4 has 'time period' confused with 'time point sequence' and I posted a separate issue to that effect.  The resolution of that issue may affect the proposed Note about 'finite time scale subdivides time point' being related to 'time point converts to time point sequence on time scale'.


It is not clear whether we are talking about subdividing time intervals or lashing up time scales, but it seems these two fact types are closely related.


-Ed


P.S.  I changed the names of the stereotypes in the UML model to match the terms in SBVR v1.1.  So all the new diagrams we generate will have the proper stereotypes.


  


-- 
Edward J. Barkmeyer                        Email: edbark@nist.gov
National Institute of Standards & Technology
Manufacturing Systems Integration Division
100 Bureau Drive, Stop 8263                Tel: +1 301-975-3528
Gaithersburg, MD 20899-8263                Cel: +1 240-672-5800


"The opinions expressed above do not reflect consensus of NIST, and have not been reviewed by any Government authority."





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To: date-time-ftf@omg.org
Subject: Re: Issue 16951 -- time point subdivision - revised draft resolution
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I inserted some minor comments and made some SBVR SE styling corrections in the last Note under "finite time scale subdivides time point".  Comment: it seems to me that the definition of this verb concept should reference the concept 'time point sequence'.  In which case, maybe this verb concept belongs after the definition of 'tie point sequence' in 9.3.   
--------------------------------
Mark H. Linehan
STSM, Model Driven Business Transformation
IBM Research 



From:        Ed Barkmeyer <edbark@nist.gov> 
To:        OMG DateTimeVoc FTF <date-time-ftf@omg.org> 
Date:        03/13/2012 12:46 PM 
Subject:        Re: Issue 16951 -- time point subdivision - revised draft resolution 

--------------------------------------------------------------------------------



Observing that all the uses of 'finite time scale subdivides time point' 
are about generating the component time points, not the time intervals, 
I revised the definition in the attached draft (d2).

-Ed


Ed Barkmeyer wrote:
> See attached.
>
> I noted that the text of clause 12.4 has 'time period' confused with 
> 'time point sequence' and I posted a separate issue to that effect.  The 
> resolution of that issue may affect the proposed Note about 'finite time 
> scale subdivides time point' being related to 'time point converts to 
> time point sequence on time scale'.
>
> It is not clear whether we are talking about subdividing time intervals 
> or lashing up time scales, but it seems these two fact types are closely 
> related.
>
> -Ed
>
> P.S.  I changed the names of the stereotypes in the UML model to match 
> the terms in SBVR v1.1.  So all the new diagrams we generate will have 
> the proper stereotypes.
>
>   

-- 
Edward J. Barkmeyer                        Email: edbark@nist.gov
National Institute of Standards & Technology
Manufacturing Systems Integration Division
100 Bureau Drive, Stop 8263                Tel: +1 301-975-3528
Gaithersburg, MD 20899-8263                Cel: +1 240-672-5800

"The opinions expressed above do not reflect consensus of NIST, 
and have not been reviewed by any Government authority."

[attachment "Issue 16951-time point subdivision-d2.doc" deleted by Mark H Linehan/Watson/IBM] 


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Subject: Re: Issue 16951 -- time point subdivision - revised draft resolution
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I inserted some minor comments and made some SBVR SE styling corrections in the last Note under "finite time scale subdivides time point".  Comment: it seems to me that the definition of this verb concept should reference the concept 'time point sequence'.  In which case, maybe this verb concept belongs after the definition of 'tie point sequence' in 9.3.   
--------------------------------
Mark H. Linehan
STSM, Model Driven Business Transformation
IBM Research 



From:        Ed Barkmeyer <edbark@nist.gov> 
To:        OMG DateTimeVoc FTF <date-time-ftf@omg.org> 
Date:        03/13/2012 12:46 PM 
Subject:        Re: Issue 16951 -- time point subdivision - revised draft resolution 

--------------------------------------------------------------------------------



Observing that all the uses of 'finite time scale subdivides time point' 
are about generating the component time points, not the time intervals, 
I revised the definition in the attached draft (d2).

-Ed


Ed Barkmeyer wrote:
> See attached.
>
> I noted that the text of clause 12.4 has 'time period' confused with 
> 'time point sequence' and I posted a separate issue to that effect.  The 
> resolution of that issue may affect the proposed Note about 'finite time 
> scale subdivides time point' being related to 'time point converts to 
> time point sequence on time scale'.
>
> It is not clear whether we are talking about subdividing time intervals 
> or lashing up time scales, but it seems these two fact types are closely 
> related.
>
> -Ed
>
> P.S.  I changed the names of the stereotypes in the UML model to match 
> the terms in SBVR v1.1.  So all the new diagrams we generate will have 
> the proper stereotypes.
>
>   

-- 
Edward J. Barkmeyer                        Email: edbark@nist.gov
National Institute of Standards & Technology
Manufacturing Systems Integration Division
100 Bureau Drive, Stop 8263                Tel: +1 301-975-3528
Gaithersburg, MD 20899-8263                Cel: +1 240-672-5800

"The opinions expressed above do not reflect consensus of NIST, 
and have not been reviewed by any Government authority."

[attachment "Issue 16951-time point subdivision-d2.doc" deleted by Mark H Linehan/Watson/IBM] 


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To: date-time-ftf@omg.org
Subject: Fw: Issue 16951 -- time point subdivision - revised draft resolution
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I see that I originally sent the wrong attachment .... 
--------------------------------
Mark H. Linehan
STSM, Model Driven Business Transformation
IBM Research 
----- Forwarded by Mark H Linehan/Watson/IBM on 03/27/2012 11:13 AM ----- 

From:        Mark H Linehan/Watson/IBM@IBMUS 
To:        date-time-ftf@omg.org 
Date:        03/25/2012 01:59 PM 
Subject:        Re: Issue 16951 -- time point subdivision - revised draft resolution 

--------------------------------------------------------------------------------



I inserted some minor comments and made some SBVR SE styling corrections in the last Note under "finite time scale subdivides time point".  Comment: it seems to me that the definition of this verb concept should reference the concept 'time point sequence'.  In which case, maybe this verb concept belongs after the definition of 'tie point sequence' in 9.3.   
--------------------------------
Mark H. Linehan
STSM, Model Driven Business Transformation
IBM Research 



From:        Ed Barkmeyer <edbark@nist.gov> 
To:        OMG DateTimeVoc FTF <date-time-ftf@omg.org> 
Date:        03/13/2012 12:46 PM 
Subject:        Re: Issue 16951 -- time point subdivision - revised draft resolution 

--------------------------------------------------------------------------------



Observing that all the uses of 'finite time scale subdivides time point' 
are about generating the component time points, not the time intervals, 
I revised the definition in the attached draft (d2).

-Ed


Ed Barkmeyer wrote:
> See attached.
>
> I noted that the text of clause 12.4 has 'time period' confused with 
> 'time point sequence' and I posted a separate issue to that effect.  The 
> resolution of that issue may affect the proposed Note about 'finite time 
> scale subdivides time point' being related to 'time point converts to 
> time point sequence on time scale'.
>
> It is not clear whether we are talking about subdividing time intervals 
> or lashing up time scales, but it seems these two fact types are closely 
> related.
>
> -Ed
>
> P.S.  I changed the names of the stereotypes in the UML model to match 
> the terms in SBVR v1.1.  So all the new diagrams we generate will have 
> the proper stereotypes.
>
>   

-- 
Edward J. Barkmeyer                        Email: edbark@nist.gov
National Institute of Standards & Technology
Manufacturing Systems Integration Division
100 Bureau Drive, Stop 8263                Tel: +1 301-975-3528
Gaithersburg, MD 20899-8263                Cel: +1 240-672-5800

"The opinions expressed above do not reflect consensus of NIST, 
and have not been reviewed by any Government authority."

[attachment "Issue 16951-time point subdivision-d2.doc" deleted by Mark H Linehan/Watson/IBM] [attachment "Issue 16992- Axiom D4-d1 MHL.doc" deleted by Mark H Linehan/Watson/IBM] 

 Issue 16951-time point subdivision-d2 MHL.doc <Down>
<Down>
<Down>
Disposition: Resolved
OMG Issue No:  16951 
Title:	Time point subdivision is out of place twice
Source: Ed Barkmeyer, NIST, edbark@nist.gov

Summary:
At the end of section 9.3 the fact type 'finite time scale subdivides time point' is defined and depicted in Figure 9-6.  This fact type is a commonly used property of finite time scales, and is not specific to individual time points.  That is, the finite time scale day-of-hours subdivides every day-of-month, for example.  So the text and diagram should be at the end of 9.2, where finite time scale is defined. 
Also, diagram 9-6 does not show the operations on time point and finite time scale that are associated with this fact type and shown in diagram 12-12.
Finally, diagram 12-12 (section 12.4) shows this fact type as well, but section 12.4 never uses it, and diagram 12-12 shows a <<specialization>> relationship that is never discussed anywhere in the text.  If the relationship is important, it should be discussed.  Otherwise, the subdivision association is out of place in diagram 12-12 and the "specialization" dependency should be deleted from the UML model.
Recommendation: Move the diagram and text for 'finite time scale subdivides time point' to the end of 9.2, include the operations on the diagram.  Delete the fact type from diagram 12-12, and delete the "specialization" dependency altogether.
Resolution:
The FTF agrees that the fact-type 'finite time scale subdivides time point' should be moved to 9.2, along with Figure 9-6, and properly described there.  It should be deleted from diagram 12-12. 
The "specialization" dependency should be deleted entirely. The intent is that this is a special case of 'time point converts to time point sequence on time scale', and that should be mentioned in a Note.
The definition in 9.3 is inaccurate.  What is meant is that the corresponding time intervals are subdivided into intervals that the relative time points of the finite time scale correspond to.  
Revised Text:
1.  At the end of 9.2, after the entry for 'relative time point', ADD the following:  (Note the additional diagram will cause renumbering of the diagrams thru 9.6.)

 
Figure 9.4: Time Scale Subdivision
finite time scale subdivides time point
Definition:	the finite time scale divides the time point into the sequence of consecutive time points  that make up  the finite time scale, and implicitly divides each time interval that the time point corresponds to into a sequence of consecutive time intervals, such that each time point on the finite time scale corresponds to exactly one of the time intervals.
Necessity:	If a finite time scale subdivides a time point, the granularity of the time scale of the time point is equal to the cardinality of the finite time scale times the granularity of the finite time scale.
Example:	The day of hours scale subdivides Gregorian date 3 January 2010 into 24 hour of day time points, and implicitly divides the time interval corresponding to Gregorian date 3 January 2010 into 24 time intervals, each of which corresponds to one hour-of-day.
Note:	A finite time scale is a time point sequence (see 9.3) and the subdivision of a time point is a special case of time point converts to time point sequence on time scale (see 12.4).  In this case, the time point sequence is the entire finite time scale.

2.  At the end of 9.3, DELETE the Figure 9.6 and the following text:
(Figure 9.6)
Figure 9.6: Time Scale Subdivision
finite time scale subdivides time point
Definition:	the finite time scale divides the time point into a number of time intervals that each have a duration, and the number is the cardinality of the finite time scale, and the duration is the granularity of the finite time scale
Example:	The day of hours scale subdivides the Gregorian date 3 January 2010 into 24 time intervals, each of duration "hour"

3.  In 12.4, REPLACE Figure 12.12 with:

 

Disposition:	Resolved

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Per today's conference call, I attach the revised drafts for resolution of Issues
16689 - D0 should be quantified (added the UML object D0)
16951 - time point subdivision (see markup),
17367- no smallest time interval (1st draft, needs OCL)


For 16689, should we have defined a term like 'zero duration'?  Should that be the term and D0 the Synonym?


-Ed


-- 
Edward J. Barkmeyer                        Email: edbark@nist.gov
National Institute of Standards & Technology
Manufacturing Systems Integration Division
100 Bureau Drive, Stop 8263                Tel: +1 301-975-3528
Gaithersburg, MD 20899-8263                Cel: +1 240-672-5800







 DTV Issue 17367- no smallest time interval-d1.docx 


 DTV Issue 16689-D0 should be quantified1.docx 


 DTV Issue 16951-time point subdivision-d4.doc 


Disposition: Resolved
OMG Issue No:  16951 
Title:	Time point subdivision is out of place twice
Source: Ed Barkmeyer, NIST, edbark@nist.gov

Summary:
At the end of section 9.3 the fact type 'finite time scale subdivides time point' is defined and depicted in Figure 9-6.  This fact type is a commonly used property of finite time scales, and is not specific to individual time points.  That is, the finite time scale day-of-hours subdivides every day-of-month, for example.  So the text and diagram should be at the end of 9.2, where finite time scale is defined. 
Also, diagram 9-6 does not show the operations on time point and finite time scale that are associated with this fact type and shown in diagram 12-12.
Finally, diagram 12-12 (section 12.4) shows this fact type as well, but section 12.4 never uses it, and diagram 12-12 shows a <<specialization>> relationship that is never discussed anywhere in the text.  If the relationship is important, it should be discussed.  Otherwise, the subdivision association is out of place in diagram 12-12 and the "specialization" dependency should be deleted from the UML model.
Recommendation: Move the diagram and text for 'finite time scale subdivides time point' to the end of 9.2, include the operations on the diagram.  Delete the fact type from diagram 12-12, and delete the "specialization" dependency altogether.
Resolution:
The FTF agrees that the fact-type 'finite time scale subdivides time point' should be moved, along with Figure 9-6, but it depends on concepts defined in 9.3 and 9.4. It is an important concept that should have its own subsection.
The definition in 9.3 is inaccurate.  What is meant is that the corresponding time intervals are subdivided into intervals that the relative time points of the finite time scale correspond to.  
The concept should not appear in diagram 12-12. The "specialization" dependency should be deleted entirely. The intent is that this is a special case of 'time point converts to time point sequence on time scale', and that should be mentioned in a Note.
Revised Text:
1.  At the end of 9.3, DELETE the Figure 9.6 and the following text:
(Figure 9.6)
Figure 9.6: Time Scale Subdivision
finite time scale subdivides time point
Definition:	the finite time scale divides the time point into a number of time intervals that each have a duration, and the number is the cardinality of the finite time scale, and the duration is the granularity of the finite time scale
Example:	The day of hours scale subdivides the Gregorian date 3 January 2010 into 24 time intervals, each of duration "hour"

2.  Immediately before section 9.5, create a new subsection: 
9.4bis Time Point Subdivision
The purpose of finite time scales is to provide finer-grained resolution of time intervals within the time intervals that are instances of time points with coarser granularities.  In this specification the relationship between a finite time scale and a coarser time point is called .time point subdivision..  Many finite time scales are defined by the category of time point they subdivide and the granularity of the time points they contain.
 
Figure 9.x: Time Scale Subdivision
finite time scale subdivides time point
Definition:	the finite time scale divides the time point into a time point sequence on that is a subsequence of the finite time scale and includes the index origin member of the finite time scale, and that implicitly divides each time interval that the time point corresponds to into a consecutive sequence of time intervals, such that each time point of the time point sequence corresponds to exactly one of the time intervals.
Necessity:	If a finite time scale subdivides a time point, the granularity of the time scale of the time point is equal to the cardinality of the time point sequence times the granularity of the finite time scale.
Necessity:	If a finite time scale subdivides a time point, there is a time point sequence such that  
  the time point sequence is on the finite time scale and
  the first time point of the time point sequence isthat begins with the index origin member of the finite time scale, and
  the time point sequencethat corresponds to each time interval that is an instance of the time point, and
  each time interval that the time point corresponds to is equal to the cardinality of the time point sequence times the granularity of the finite time scale.  
Example:	The day of hours scale subdivides Gregorian date 3 January 2010 into 24 hour of day time points, and implicitly divides the time interval corresponding to Gregorian date 3 January 2010 into 24 time intervals, each of which corresponds to one hour-of-day.
Note:	A finite time scale is a time point sequence (see 9.3) and the subdivision of a time point is a special case of time point converts to time point sequence on time scale (see 12.4).  

[Editorial Note: Diagram 12-12 is modified by other issues.] 

Disposition:	Resolved

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Subject: Re: DTV Issues 16689, 16951, 17367 proposed resolutions
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Regarding 16689: 
* I don't see the value of this CLIF axiom; it doesn't seem to say anything.  The one proposed to go after axiom V1 seems sufficient. 
CLIF Definition:        (forall ((d1 duration) (d2 duration) d3)
 (iff
   (= d3 (+ d1 d2))
   (and
     (duration d3)
     ("duration3 = duration1 + duration2"
        d3 d1 d2) ))) 
* I don't have a strong opinion about 'D0' versus 'zero duration'.  I don't see a lot of value in using the term 'zero duration' instead of 'D0'. 

Regarding 16951: 
* Editorial instruction #2 should make it clear that the new subsection has a regular section number, not the literal "9.4bis".  Something like "Immediately before clause 9.5, create a new subclause:", and renumber subclauses 9.5 and 9.6 as 9.6 and 9.7".  And then show "9.4bis" as "9.4". 
* I notice that all the uses of the 'subdivides' verb concept are of the form "<finite time scale> subdivides <time point> into <number> of <time point>".  Which makes me wonder whether the verb concept should have 4 roles rather than 2. 
* There should be a Note that explains why we talk about a subsequence of the finite time scale.  The reason is that the subdivision of some kinds of time points into finite time scales is irregular.  Months are subdivided into 28-31 days and years are subdivided into 365 or 366 days. 
* But, looking further, all of the uses of this verb concept talk about subdividing the "larger" time point into a fixed (not varying) number of "smaller" time points.  For example, the 'Gregorian year of days scale' is defined as "the finite time scale that subdivides âGregorian yearâ into 366 of âGregorian day of yearâ ".  Should it talk about subdividing leap years into 366 and common years into 365 'Gregorian day of year'?  Should the 'Gregorian month of days scale' be explicit about how it divides each of the Gregorian months?  What do we do about the 'year of weeks scale' since the number of weeks in a year is really messy? 
* The wording of the Necessity seems like something a logician would write not something that makes business sense.  The phrase "If a finite time scale subdivides a time point," should not be needed since the Necessity is in the context of this verb concept.  (In any case, this Necessity will be rewritten if my point about missing roles is accepted.) 
* I agree that this verb concept is related to 'time point converts to time point sequence on time scale' but I don't agree that this verb concept is a 'special case' of the latter.  This verb concept is about the definitional relationship between finite time scales and time points; whereas the other is about computing the conversion. 

Regarding 17367: 
* I think that the OCL for the new axiom in 8.1.1 should read, as follows -- but need to consult the OCL book when I get home to be sure: 
OCL Constraint:        context: "time interval" 
                                   inv: "time interval"."time interval1 is proper part of time interval2"-->notEmpty() 
* Why not wrap the new axiom in 8.1.6 into the definition of 'properly during'?  Why should it be a separate axiom? 
* I haven't provided the OCL for this new axiom because I think it instead should be a modification of the definitional OCL for 'properly during'. 
* I think that what Fabian asked for is a different new axiom that says that every time interval has a proper part that starts/finishes it. 
-------------------------------
Mark H. Linehan
STSM, IBM Research 



From:        Ed Barkmeyer <edbark@nist.gov> 
To:        OMG DateTimeVoc FTF <date-time-ftf@omg.org>, 
Date:        07/16/2012 07:23 PM 
Subject:        DTV Issues 16689, 16951, 17367 proposed resolutions 

--------------------------------------------------------------------------------



Per today's conference call, I attach the revised drafts for resolution 
of Issues
16689 - D0 should be quantified (added the UML object D0)
16951 - time point subdivision (see markup),
17367- no smallest time interval (1st draft, needs OCL)

For 16689, should we have defined a term like 'zero duration'?  Should 
that be the term and D0 the Synonym?

-Ed

-- 
Edward J. Barkmeyer                        Email: edbark@nist.gov
National Institute of Standards & Technology
Manufacturing Systems Integration Division
100 Bureau Drive, Stop 8263                Tel: +1 301-975-3528
Gaithersburg, MD 20899-8263                Cel: +1 240-672-5800



[attachment "DTV Issue 17367- no smallest time interval-d1.docx" deleted by Mark H Linehan/Watson/IBM] [attachment "DTV Issue 16689-D0 should be quantified.docx" deleted by Mark H Linehan/Watson/IBM] [attachment "DTV Issue 16951-time point subdivision-d4.doc" deleted by Mark H Linehan/Watson/IBM] 
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CC: "date-time-ftf@omg.org" <date-time-ftf@omg.org>,
        Stan Hendryx
        <stan@hendryxassoc.com>
Subject: Re: DTV Issues 16689, 16951, 17367 proposed resolutions
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Mark H Linehan wrote: 
Regarding 16689: 
* I don't see the value of this CLIF axiom; it doesn't seem to say anything.  The one proposed to go after axiom V1 seems sufficient. 
CLIF Definition:        (forall ((d1 duration) (d2 duration) d3)
 (iff
   (= d3 (+ d1 d2))
   (and
     (duration d3)
     ("duration3 = duration1 + duration2"
        d3 d1 d2) ))) 


This axiom defines the function (+ d1 d2).  Otherwise it is primitive, and not clearly related to the predicate "duration3 = duration1 + duration2".  Or at least, I think that is the case.  The proposed axiom for V1 says that the function is defined everywhere:
(forall ((d1 duration) (d2 duration))
  (exists (d3 duration) 
    (= d3 (+ d1 d2)) )))
  
* I don't have a strong opinion about 'D0' versus 'zero duration'.  I don't see a lot of value in using the term 'zero duration' instead of 'D0'. 

In SBVR parlance, D0 is a symbol, 'zero duration' is a term.  Given that it is a term for something that is strictly a mathematical concept, it probably makes no difference.


Regarding 16951: 
* Editorial instruction #2 should make it clear that the new subsection has a regular section number, not the literal "9.4bis".  Something like "Immediately before clause 9.5, create a new subclause:", and renumber subclauses 9.5 and 9.6 as 9.6 and 9.7".  And then show "9.4bis" as "9.4". 


OK.


* I notice that all the uses of the 'subdivides' verb concept are of the form "<finite time scale> subdivides <time point> into <number> of <time point>".  Which makes me wonder whether the verb concept should have 4 roles rather than 2. 


Hmm.  I think the original verb was based on the idea that the subdivision was like hours and minutes -- the whole finite time scale.  But of course that was never true for month-of-days or year-of-days.  The subdivision really uses a time point sequence beginning with the origin index, which is what the proposed revised definition says.  But that 'time point sequence' idea may be wrong.  That is, I think a time point sequence is different from a sequence of time points, and 'subdivides' is about that difference.

Technically a sequence of time points corresponds to sequences of time intervals.  We say a 'time point sequence' corresponds to the one big interval that is the span (hull) of the sequence of intervals.  Now the 'one big interval' view is consistent with the idea that '2:00 to 4:00' indicates a time point sequence that corresponds to intervals that have a duration of two hours (or correctly 120 minutes).  But that is not what we mean by 'subdivides',  We mean treating the larger time point as a sequence of time points that corresponds to sequences of smaller time intervals, rather than to the hull of them.  This leads me to think that the term 'time point sequence' violates (Bernd Wenzel's) Law of Least Astonishment.  That is 'time point sequence' is not the same as 'sequence of time points'.


* There should be a Note that explains why we talk about a subsequence of the finite time scale.  The reason is that the subdivision of some kinds of time points into finite time scales is irregular.  Months are subdivided into 28-31 days and years are subdivided into 365 or 366 days. 


Agree.


* But, looking further, all of the uses of this verb concept talk about subdividing the "larger" time point into a fixed (not varying) number of "smaller" time points.  For example, the 'Gregorian year of days scale' is defined as "the finite time scale that subdivides .Gregorian year. into 366 of .Gregorian day of year. ".  Should it talk about subdividing leap years into 366 and common years into 365 'Gregorian day of year'?  Should the 'Gregorian month of days scale' be explicit about how it divides each of the Gregorian months?  What do we do about the 'year of weeks scale' since the number of weeks in a year is really messy? 


I guess we need to discuss this.  I agree with Mark's concern here, but I don't know what we want to write.  And <expletive deleted> leap seconds make minute-of-seconds or day-of-seconds truly variable.  


* The wording of the Necessity seems like something a logician would write not something that makes business sense.  The phrase "If a finite time scale subdivides a time point," should not be needed since the Necessity is in the context of this verb concept.  (In any case, this Necessity will be rewritten if my point about missing roles is accepted.) 


Yes.  This is part of the above.


* I agree that this verb concept is related to 'time point converts to time point sequence on time scale' but I don't agree that this verb concept is a 'special case' of the latter.  This verb concept is about the definitional relationship between finite time scales and time points; whereas the other is about computing the conversion. 


The Beta text of this verb concept is broken.  The replacement text from Issue 17227 says:

<!--[if !supportLists]-->Definition:                             <!--[endif]-->the time point is coextensive with the time point sequence

<!--[if !supportLists]-->Necessity:                              <!--[endif]-->Each time point of the time point sequence is on the time scale.

<!--[if !supportLists]-->Possibility:                             <!--[endif]-->The time point is an absolute time point or is a relative time point.

<!--[if !supportLists]-->Description:                          <!--[endif]-->The time point and the time point sequence are two different ways to identify the same time intervals.


It doesn't say anything about computation.  The purpose is to provide meaning to the idea of computing the referents of a time coordinate, yes.  The Beta text indicated that intent -- it was trying to say that the decomposition into time points was about identifying time periods.  But the mechanism is said here to involve the conversion to an equivalent sequence of time points.  The example for 17227:


<!--[if !supportLists]-->Example:                                 <!--[endif]-->The time point that is indicated by the time coordinate January 2012 converts to the time point sequence 2012 day 1 through 2012 day 31 on the Gregorian days scale.


shows that the intent is different from 'subdivides'.  'subdivides' is about converting January 2012 to the month-of-days; this is about converting it to a subsequence of 'day-of-year'.

But this takes us back to the idea above, that there are two different time point sequence ideas.  I think the 'converts to' idea is about locating the larger interval in a longer sequence of finer granularity intervals, as the large interval that is the hull of a subsequence, while 'subdivides' is about treating the larger time point as a sequence of consecutive time points that corresponds to sequences of consecutive smaller time intervals.  That is, 'converts to' is not about decomposing the time point and its corresponding time periods, it is about locating it in some other sequence; but subdivides is about decomposing the time point and its corresponding time periods.  

So I agree with Mark that 'subdivides' is not a special case of 'converts to', but we somehow have to be clear about the difference in intent in the definitions.  They both seem to say:  "time point on scale A is coextensive with time point sequence on scale B."  17227 is correct that that is what converts to means.  For 'subdivides' we have to talk about sequences of time intervals, somehow.


Regarding 17367: 
* I think that the OCL for the new axiom in 8.1.1 should read, as follows -- but need to consult the OCL book when I get home to be sure: 
OCL Constraint:        context: "time interval" 
                                   inv: "time interval"."time interval1 is proper part of time interval2"-->notEmpty() 


OK.  I will put that in the next draft, with a comment that says 'check this'.


* Why not wrap the new axiom in 8.1.6 into the definition of 'properly during'?  Why should it be a separate axiom? 
* I haven't provided the OCL for this new axiom because I think it instead should be a modification of the definitional OCL for 'properly during'. 


Well, 'properly during' is one of the Allen relations, and it is defined in terms of 'part of ' and 'before'.  'properly during' just says there is a proper part that is before it and one that is after it, which logically completes the partitioning of 'proper part': starts has no before, finishes has no after, and during has both.  What Mark suggests is that 'A is properly during B' could be defined as:  A is a proper part of B and there is a time interval C such that C starts B and C meets A, etc.  That does not clearly complete the partition.  To complete it, you would have to prove that:  If A does not start or finish B, then there is a C that starts B and meets A.   That is, if there is a C that is a proper part of B and is before A (i.e. A does not start B), then there is a C' that starts B and meets A.  And that is what the proposed axiom says, because you can't prove it from the other axioms.

In a similar way, the weak supplementation axiom says that for every proper part there is another proper part that does not overlap it.  So if A starts B, A has a supplement and the supplement must be after A.  But there is a 'start complement' axiom that says that if A starts B, there is a C that is met by A and finishes B -- the "maximal" supplement.  I don't think you can get these "maximal supplement" theorems from the axioms for 'part of' and 'before', precisely because we don't have strong supplementation:  If A is properly during B, then B-A is not a time interval.


* I think that what Fabian asked for is a different new axiom that says that every time interval has a proper part that starts/finishes it. 


Ah!  But those follow from the proposed axiom, together with the existing start-complement and finish-complement axioms.  E.g.
Theorem:  Every time interval has a proper part that starts it.
Proof:
If a time interval B has a proper part A, then (by the Allen partitioning), one of the following must be true: A starts B, A finishes B, A is properly during B.
Now, if A starts B, B has a proper part (A) that starts it.
If A finishes B, by the finish complement axiom, there is a C that starts B and meets A.  So B has a proper part (C) that starts it.
If A is during B, by the proposed axiom, there is a C that starts B and meets A.  So B has a proper part (C) that starts it.
So, if a time interval B has a proper part A, B has a proper part that starts B in all cases.  
By the no-smallest-interval axiom, every time interval B has some proper part A.  
So every time interval B has a proper part that starts B in all cases.  Q.E.D.
 
The nagging question is whether there might be a simpler solution than having these three complement axioms.  In particular, could we instead assert that every time interval has a proper part that starts it and a proper part that finishes it?  I think not, because there is no basis for relating an arbitrary starting part to an arbitrary finishing part.

-Ed


-- 
Edward J. Barkmeyer                        Email: edbark@nist.gov
National Institute of Standards & Technology
Manufacturing Systems Integration Division
100 Bureau Drive, Stop 8263                Tel: +1 301-975-3528
Gaithersburg, MD 20899-8263                Cel: +1 240-672-5800

"The opinions expressed above do not reflect consensus of NIST, 
 and have not been reviewed by any Government authority."




-------------------------------
Mark H. Linehan
STSM, IBM Research 



From:        Ed Barkmeyer <edbark@nist.gov> 
To:        OMG DateTimeVoc FTF <date-time-ftf@omg.org>, 
Date:        07/16/2012 07:23 PM 
Subject:        DTV Issues 16689, 16951, 17367 proposed resolutions 

--------------------------------------------------------------------------------



Per today's conference call, I attach the revised drafts for resolution 
of Issues
16689 - D0 should be quantified (added the UML object D0)
16951 - time point subdivision (see markup),
17367- no smallest time interval (1st draft, needs OCL)

For 16689, should we have defined a term like 'zero duration'?  Should 
that be the term and D0 the Synonym?

-Ed

-- 
Edward J. Barkmeyer                        Email: edbark@nist.gov
National Institute of Standards & Technology
Manufacturing Systems Integration Division
100 Bureau Drive, Stop 8263                Tel: +1 301-975-3528
Gaithersburg, MD 20899-8263                Cel: +1 240-672-5800



[attachment "DTV Issue 17367- no smallest time interval-d1.docx" deleted by Mark H Linehan/Watson/IBM] [attachment "DTV Issue 16689-D0 should be quantified.docx" deleted by Mark H Linehan/Watson/IBM] [attachment "DTV Issue 16951-time point subdivision-d4.doc" deleted by Mark H Linehan/Watson/IBM] 


To: "date-time-ftf@omg.org" <date-time-ftf@omg.org>,
        Stan Hendryx <stan@hendryxassoc.com>
Subject: Re: DTV Issues 16689, 16951, 17367 proposed resolutions
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Ed, 

Regarding 16689:  Why isn't the  function (+ d1 d2) just a noun form of the predicate "duration3 = duration1 + duration2"? 

Regarding 16951:  I don't think we need to distinguish "time point sequence" from "sequence of time points".  I think these are just two views of the same thing: either the time interval that corresponds to the convex hull of the whole time point sequence, or a sequence of time intervals that correspond to the individual time points of the time point sequence.  I think the two verb concepts ('subdivides' and 'converts to') are two different ways of using the one general concept. 

Regarding how to define the time scales that irregularly subdivide time points, here's an example of what I suggest we should write: 

"Gregorian year of days scale: the finite time scale that subdivides âcommon yearâ into 365 of âGregorian day of yearâ and that subdivides 'leap year' into 366 of âGregorian day of yearâ. 

I don't think leap seconds have anything to do with this discussion.  Leap seconds involve displacing the UTC time scale, not adding seconds to calendar days.  BIPM is clear that 'day' is fixed at 86400 seconds. 

Regarding 17367: OK on adding the new axiom.  Here's the OCL, I think: 

OCL Definition:        context "time interval" 
                        inv: "time interval".allInstances-->forAll(t2 | 
                                       t2."is properly during"(self) 
                                                   implies "time interval".allInstances-->exists(t3 | 
                                                        t3.starts(self) and t3.meets(t2))) 
                        context "time interval" 
                        inv: "time interval".allInstances-->forAll(t2 | 
                                       t2." is properly during"(self) 
                                                   implies "time interval".allInstances-->exists(t3 | 
                                                        t3.ends(self) and t2.meets(t3))) 

I think we should make explicit the new axiom requested by Fabian. 
--------------------------------
Mark H. Linehan
STSM, IBM Research 



From:        Ed Barkmeyer <edbark@nist.gov> 
To:        Mark H Linehan/Watson/IBM@IBMUS, 
Cc:        "date-time-ftf@omg.org" <date-time-ftf@omg.org>, Stan Hendryx <stan@hendryxassoc.com> 
Date:        07/26/2012 01:19 PM 
Subject:        Re: DTV Issues 16689, 16951, 17367 proposed resolutions 



--------------------------------------------------------------------------------





Mark H Linehan wrote: 
Regarding 16689: 
* I don't see the value of this CLIF axiom; it doesn't seem to say anything.  The one proposed to go after axiom V1 seems sufficient. 
CLIF Definition:        (forall ((d1 duration) (d2 duration) d3)
 (iff
   (= d3 (+ d1 d2))
   (and
     (duration d3)
     ("duration3 = duration1 + duration2"
        d3 d1 d2) ))) 

This axiom defines the function (+ d1 d2).  Otherwise it is primitive, and not clearly related to the predicate "duration3 = duration1 + duration2".  Or at least, I think that is the case.  The proposed axiom for V1 says that the function is defined everywhere:
(forall ((d1 duration) (d2 duration))
  (exists (d3 duration) 
    (= d3 (+ d1 d2)) )))
  
* I don't have a strong opinion about 'D0' versus 'zero duration'.  I don't see a lot of value in using the term 'zero duration' instead of 'D0'. 

In SBVR parlance, D0 is a symbol, 'zero duration' is a term.  Given that it is a term for something that is strictly a mathematical concept, it probably makes no difference.

Regarding 16951: 
* Editorial instruction #2 should make it clear that the new subsection has a regular section number, not the literal "9.4bis".  Something like "Immediately before clause 9.5, create a new subclause:", and renumber subclauses 9.5 and 9.6 as 9.6 and 9.7".  And then show "9.4bis" as "9.4". 

OK.

* I notice that all the uses of the 'subdivides' verb concept are of the form "<finite time scale> subdivides <time point> into <number> of <time point>".  Which makes me wonder whether the verb concept should have 4 roles rather than 2. 

Hmm.  I think the original verb was based on the idea that the subdivision was like hours and minutes -- the whole finite time scale.  But of course that was never true for month-of-days or year-of-days.  The subdivision really uses a time point sequence beginning with the origin index, which is what the proposed revised definition says.  But that 'time point sequence' idea may be wrong.  That is, I think a time point sequence is different from a sequence of time points, and 'subdivides' is about that difference.

Technically a sequence of time points corresponds to sequences of time intervals.  We say a 'time point sequence' corresponds to the one big interval that is the span (hull) of the sequence of intervals.  Now the 'one big interval' view is consistent with the idea that '2:00 to 4:00' indicates a time point sequence that corresponds to intervals that have a duration of two hours (or correctly 120 minutes).  But that is not what we mean by 'subdivides',  We mean treating the larger time point as a sequence of time points that corresponds to sequences of smaller time intervals, rather than to the hull of them.  This leads me to think that the term 'time point sequence' violates (Bernd Wenzel's) Law of Least Astonishment.  That is 'time point sequence' is not the same as 'sequence of time points'.

* There should be a Note that explains why we talk about a subsequence of the finite time scale.  The reason is that the subdivision of some kinds of time points into finite time scales is irregular.  Months are subdivided into 28-31 days and years are subdivided into 365 or 366 days. 

Agree.

* But, looking further, all of the uses of this verb concept talk about subdividing the "larger" time point into a fixed (not varying) number of "smaller" time points.  For example, the 'Gregorian year of days scale' is defined as "the finite time scale that subdivides âGregorian yearâ into 366 of âGregorian day of yearâ ".  Should it talk about subdividing leap years into 366 and common years into 365 'Gregorian day of year'?  Should the 'Gregorian month of days scale' be explicit about how it divides each of the Gregorian months?  What do we do about the 'year of weeks scale' since the number of weeks in a year is really messy? 

I guess we need to discuss this.  I agree with Mark's concern here, but I don't know what we want to write.  And <expletive deleted> leap seconds make minute-of-seconds or day-of-seconds truly variable.  

* The wording of the Necessity seems like something a logician would write not something that makes business sense.  The phrase "If a finite time scale subdivides a time point," should not be needed since the Necessity is in the context of this verb concept.  (In any case, this Necessity will be rewritten if my point about missing roles is accepted.) 

Yes.  This is part of the above.

* I agree that this verb concept is related to 'time point converts to time point sequence on time scale' but I don't agree that this verb concept is a 'special case' of the latter.  This verb concept is about the definitional relationship between finite time scales and time points; whereas the other is about computing the conversion. 

The Beta text of this verb concept is broken.  The replacement text from Issue 17227 says: 
Definition:                             the time point is coextensive with the time point sequence 

Necessity:                              Each time point of the time point sequence is on the time scale. 

Possibility:                             The time point is an absolute time point or is a relative time point. 

Description:                          The time point and the time point sequence are two different ways to identify the same time intervals. 


It doesn't say anything about computation.  The purpose is to provide meaning to the idea of computing the referents of a time coordinate, yes.  The Beta text indicated that intent -- it was trying to say that the decomposition into time points was about identifying time periods.  But the mechanism is said here to involve the conversion to an equivalent sequence of time points.  The example for 17227:


Example:                                 The time point that is indicated by the time coordinate January 2012 converts to the time point sequence 2012 day 1 through 2012 day 31 on the Gregorian days scale. 


shows that the intent is different from 'subdivides'.  'subdivides' is about converting January 2012 to the month-of-days; this is about converting it to a subsequence of 'day-of-year'.

But this takes us back to the idea above, that there are two different time point sequence ideas.  I think the 'converts to' idea is about locating the larger interval in a longer sequence of finer granularity intervals, as the large interval that is the hull of a subsequence, while 'subdivides' is about treating the larger time point as a sequence of consecutive time points that corresponds to sequences of consecutive smaller time intervals.  That is, 'converts to' is not about decomposing the time point and its corresponding time periods, it is about locating it in some other sequence; but subdivides is about decomposing the time point and its corresponding time periods.  

So I agree with Mark that 'subdivides' is not a special case of 'converts to', but we somehow have to be clear about the difference in intent in the definitions.  They both seem to say:  "time point on scale A is coextensive with time point sequence on scale B."  17227 is correct that that is what converts to means.  For 'subdivides' we have to talk about sequences of time intervals, somehow.

Regarding 17367: 
* I think that the OCL for the new axiom in 8.1.1 should read, as follows -- but need to consult the OCL book when I get home to be sure: 
OCL Constraint:        context: "time interval" 
                                   inv: "time interval"."time interval1 is proper part of time interval2"-->notEmpty() 

OK.  I will put that in the next draft, with a comment that says 'check this'.

* Why not wrap the new axiom in 8.1.6 into the definition of 'properly during'?  Why should it be a separate axiom? 
* I haven't provided the OCL for this new axiom because I think it instead should be a modification of the definitional OCL for 'properly during'. 

Well, 'properly during' is one of the Allen relations, and it is defined in terms of 'part of ' and 'before'.  'properly during' just says there is a proper part that is before it and one that is after it, which logically completes the partitioning of 'proper part': starts has no before, finishes has no after, and during has both.  What Mark suggests is that 'A is properly during B' could be defined as:  A is a proper part of B and there is a time interval C such that C starts B and C meets A, etc.  That does not clearly complete the partition.  To complete it, you would have to prove that:  If A does not start or finish B, then there is a C that starts B and meets A.   That is, if there is a C that is a proper part of B and is before A (i.e. A does not start B), then there is a C' that starts B and meets A.  And that is what the proposed axiom says, because you can't prove it from the other axioms.

In a similar way, the weak supplementation axiom says that for every proper part there is another proper part that does not overlap it.  So if A starts B, A has a supplement and the supplement must be after A.  But there is a 'start complement' axiom that says that if A starts B, there is a C that is met by A and finishes B -- the "maximal" supplement.  I don't think you can get these "maximal supplement" theorems from the axioms for 'part of' and 'before', precisely because we don't have strong supplementation:  If A is properly during B, then B-A is not a time interval.

* I think that what Fabian asked for is a different new axiom that says that every time interval has a proper part that starts/finishes it. 

Ah!  But those follow from the proposed axiom, together with the existing start-complement and finish-complement axioms.  E.g.
Theorem:  Every time interval has a proper part that starts it.
Proof:
If a time interval B has a proper part A, then (by the Allen partitioning), one of the following must be true: A starts B, A finishes B, A is properly during B.
Now, if A starts B, B has a proper part (A) that starts it.
If A finishes B, by the finish complement axiom, there is a C that starts B and meets A.  So B has a proper part (C) that starts it.
If A is during B, by the proposed axiom, there is a C that starts B and meets A.  So B has a proper part (C) that starts it.
So, if a time interval B has a proper part A, B has a proper part that starts B in all cases.  
By the no-smallest-interval axiom, every time interval B has some proper part A.  
So every time interval B has a proper part that starts B in all cases.  Q.E.D.
 
The nagging question is whether there might be a simpler solution than having these three complement axioms.  In particular, could we instead assert that every time interval has a proper part that starts it and a proper part that finishes it?  I think not, because there is no basis for relating an arbitrary starting part to an arbitrary finishing part.

-Ed

-- 
Edward J. Barkmeyer                        Email: edbark@nist.gov
National Institute of Standards & Technology
Manufacturing Systems Integration Division
100 Bureau Drive, Stop 8263                Tel: +1 301-975-3528
Gaithersburg, MD 20899-8263                Cel: +1 240-672-5800

"The opinions expressed above do not reflect consensus of NIST, 
and have not been reviewed by any Government authority." 



-------------------------------
Mark H. Linehan
STSM, IBM Research 



From:        Ed Barkmeyer <edbark@nist.gov> 
To:        OMG DateTimeVoc FTF <date-time-ftf@omg.org>, 
Date:        07/16/2012 07:23 PM 
Subject:        DTV Issues 16689, 16951, 17367 proposed resolutions 



--------------------------------------------------------------------------------



Per today's conference call, I attach the revised drafts for resolution 
of Issues
16689 - D0 should be quantified (added the UML object D0)
16951 - time point subdivision (see markup),
17367- no smallest time interval (1st draft, needs OCL)

For 16689, should we have defined a term like 'zero duration'?  Should 
that be the term and D0 the Synonym?

-Ed

-- 
Edward J. Barkmeyer                        Email: edbark@nist.gov
National Institute of Standards & Technology
Manufacturing Systems Integration Division
100 Bureau Drive, Stop 8263                Tel: +1 301-975-3528
Gaithersburg, MD 20899-8263                Cel: +1 240-672-5800



[attachment "DTV Issue 17367- no smallest time interval-d1.docx" deleted by Mark H Linehan/Watson/IBM] [attachment "DTV Issue 16689-D0 should be quantified.docx" deleted by Mark H Linehan/Watson/IBM] [attachment "DTV Issue 16951-time point subdivision-d4.doc" deleted by Mark H Linehan/Watson/IBM] 

Date: Fri, 27 Jul 2012 11:12:34 -0400
From: Ed Barkmeyer <edbark@nist.gov>
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Organization: NIST
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To: Mark H Linehan <mlinehan@us.ibm.com>
CC: "date-time-ftf@omg.org" <date-time-ftf@omg.org>,
        Stan Hendryx
        <stan@hendryxassoc.com>
Subject: Re: DTV Issues 16689, 16951, 17367 proposed resolutions
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Mark H Linehan wrote: 
Ed, 

Regarding 16689:  Why isn't the  function (+ d1 d2) just a noun form of the predicate "duration3 = duration1 + duration2"?

Noun-form of a verb is an SBVR idea that is misleading.  (I raised an issue on this in the first SBVR FTF, and it was swept under the rug.) In SBVR the instances of a verb concept are actualities, but the instances of the 'noun-form' of the verb are things that play roles in the actualities.  The "extensions" are not even of the same kind.  That is why I say the SBVR term is misleading.  The "noun-form" represents the 'function' concept, which is not a 'verb concept'.  It is a different, but related, concept.  And the two concepts are related by a definition such as the CLIF definition I gave.
[In classical formal logics, a predicate (verb concept) is a mapping from a tuple of things to true/false.  (Of course, Lowe and Zalta don't agree.)  And a function is a mapping from a tuple of things to a thing.  The SBVR 'noun form' is a function, as Mark pointed out.]

The real "noun form" of a verb concept is the gerund, or a noun that objectifies the verb, as defined in clause 11.  Those concepts have the same extension.



Regarding 16951:  I don't think we need to distinguish "time point sequence" from "sequence of time points".  I think these are just two views of the same thing: either the time interval that corresponds to the convex hull of the whole time point sequence, or a sequence of time intervals that correspond to the individual time points of the time point sequence.  I think the two verb concepts ('subdivides' and 'converts to') are two different ways of using the one general concept.


OK, but my point is that those two 'views' see technically different extensions of a time point sequence.  The whole point of subdivision is to decompose the time intervals, not to see them as one big interval.  subdivides decomposes an X into Ys, converts composes Ys into an X.



Regarding how to define the time scales that irregularly subdivide time points, here's an example of what I suggest we should write: 

"Gregorian year of days scale: the finite time scale that subdivides .common year. into 365 of .Gregorian day of year. and that subdivides 'leap year' into 366 of .Gregorian day of year.. 



Yes.  I agree.


I don't think leap seconds have anything to do with this discussion.  Leap seconds involve displacing the UTC time scale, not adding seconds to calendar days.  BIPM is clear that 'day' is fixed at 86400 seconds. 



But the BIPM 'day' is a duration, a time unit.  A UTC day is a calendar day, and its length is variable, and the variation does not follow a named pattern like common year and leap year.  We don't cast 'leap seconds' as a kind of 'time offset' (from TAI to UTC), but that is what "displacing the UTC time scale" suggests.  It makes some sense.  The UTC rules are then rather like those of timezones -- some authority decides when to change from one time offset to another. We already have time offsets in hours and minutes; we could add seconds.  Is that a better approach than what we wrote?  


Regarding 17367: OK on adding the new axiom.  Here's the OCL, I think: 

OCL Definition:        context "time interval" 
                        inv: "time interval".allInstances-->forAll(t2 | 
                                       t2."is properly during"(self) 
                                                   implies "time interval".allInstances-->exists(t3 | 
                                                        t3.starts(self) and t3.meets(t2))) 
                        context "time interval" 
                        inv: "time interval".allInstances-->forAll(t2 | 
                                       t2." is properly during"(self) 
                                                   implies "time interval".allInstances-->exists(t3 | 
                                                        t3.ends(self) and t2.meets(t3))) 

I think we should make explicit the new axiom requested by Fabian. 



I agree.  I didn't realize I had not done that.

-Ed

-- 
Edward J. Barkmeyer                        Email: edbark@nist.gov
National Institute of Standards & Technology
Manufacturing Systems Integration Division
100 Bureau Drive, Stop 8263                Tel: +1 301-975-3528
Gaithersburg, MD 20899-8263                Cel: +1 240-672-5800





--------------------------------
Mark H. Linehan
STSM, IBM Research 



From:        Ed Barkmeyer <edbark@nist.gov> 
To:        Mark H Linehan/Watson/IBM@IBMUS, 
Cc:        "date-time-ftf@omg.org" <date-time-ftf@omg.org>, Stan Hendryx <stan@hendryxassoc.com> 
Date:        07/26/2012 01:19 PM 
Subject:        Re: DTV Issues 16689, 16951, 17367 proposed resolutions 



--------------------------------------------------------------------------------





Mark H Linehan wrote: 
Regarding 16689: 
* I don't see the value of this CLIF axiom; it doesn't seem to say anything.  The one proposed to go after axiom V1 seems sufficient. 
CLIF Definition:        (forall ((d1 duration) (d2 duration) d3)
 (iff
   (= d3 (+ d1 d2))
   (and
     (duration d3)
     ("duration3 = duration1 + duration2"
        d3 d1 d2) ))) 

This axiom defines the function (+ d1 d2).  Otherwise it is primitive, and not clearly related to the predicate "duration3 = duration1 + duration2".  Or at least, I think that is the case.  The proposed axiom for V1 says that the function is defined everywhere:
(forall ((d1 duration) (d2 duration))
  (exists (d3 duration) 
    (= d3 (+ d1 d2)) )))
  
* I don't have a strong opinion about 'D0' versus 'zero duration'.  I don't see a lot of value in using the term 'zero duration' instead of 'D0'. 

In SBVR parlance, D0 is a symbol, 'zero duration' is a term.  Given that it is a term for something that is strictly a mathematical concept, it probably makes no difference.

Regarding 16951: 
* Editorial instruction #2 should make it clear that the new subsection has a regular section number, not the literal "9.4bis".  Something like "Immediately before clause 9.5, create a new subclause:", and renumber subclauses 9.5 and 9.6 as 9.6 and 9.7".  And then show "9.4bis" as "9.4". 

OK.

* I notice that all the uses of the 'subdivides' verb concept are of the form "<finite time scale> subdivides <time point> into <number> of <time point>".  Which makes me wonder whether the verb concept should have 4 roles rather than 2. 

Hmm.  I think the original verb was based on the idea that the subdivision was like hours and minutes -- the whole finite time scale.  But of course that was never true for month-of-days or year-of-days.  The subdivision really uses a time point sequence beginning with the origin index, which is what the proposed revised definition says.  But that 'time point sequence' idea may be wrong.  That is, I think a time point sequence is different from a sequence of time points, and 'subdivides' is about that difference.

Technically a sequence of time points corresponds to sequences of time intervals.  We say a 'time point sequence' corresponds to the one big interval that is the span (hull) of the sequence of intervals.  Now the 'one big interval' view is consistent with the idea that '2:00 to 4:00' indicates a time point sequence that corresponds to intervals that have a duration of two hours (or correctly 120 minutes).  But that is not what we mean by 'subdivides',  We mean treating the larger time point as a sequence of time points that corresponds to sequences of smaller time intervals, rather than to the hull of them.  This leads me to think that the term 'time point sequence' violates (Bernd Wenzel's) Law of Least Astonishment.  That is 'time point sequence' is not the same as 'sequence of time points'.

* There should be a Note that explains why we talk about a subsequence of the finite time scale.  The reason is that the subdivision of some kinds of time points into finite time scales is irregular.  Months are subdivided into 28-31 days and years are subdivided into 365 or 366 days. 

Agree.

* But, looking further, all of the uses of this verb concept talk about subdividing the "larger" time point into a fixed (not varying) number of "smaller" time points.  For example, the 'Gregorian year of days scale' is defined as "the finite time scale that subdivides .Gregorian year. into 366 of .Gregorian day of year. ".  Should it talk about subdividing leap years into 366 and common years into 365 'Gregorian day of year'?  Should the 'Gregorian month of days scale' be explicit about how it divides each of the Gregorian months?  What do we do about the 'year of weeks scale' since the number of weeks in a year is really messy? 

I guess we need to discuss this.  I agree with Mark's concern here, but I don't know what we want to write.  And <expletive deleted> leap seconds make minute-of-seconds or day-of-seconds truly variable.  

* The wording of the Necessity seems like something a logician would write not something that makes business sense.  The phrase "If a finite time scale subdivides a time point," should not be needed since the Necessity is in the context of this verb concept.  (In any case, this Necessity will be rewritten if my point about missing roles is accepted.) 

Yes.  This is part of the above.

* I agree that this verb concept is related to 'time point converts to time point sequence on time scale' but I don't agree that this verb concept is a 'special case' of the latter.  This verb concept is about the definitional relationship between finite time scales and time points; whereas the other is about computing the conversion. 

The Beta text of this verb concept is broken.  The replacement text from Issue 17227 says: 
Definition:                             the time point is coextensive with the time point sequence 

Necessity:                              Each time point of the time point sequence is on the time scale. 

Possibility:                             The time point is an absolute time point or is a relative time point. 

Description:                          The time point and the time point sequence are two different ways to identify the same time intervals. 


It doesn't say anything about computation.  The purpose is to provide meaning to the idea of computing the referents of a time coordinate, yes.  The Beta text indicated that intent -- it was trying to say that the decomposition into time points was about identifying time periods.  But the mechanism is said here to involve the conversion to an equivalent sequence of time points.  The example for 17227:


Example:                                 The time point that is indicated by the time coordinate January 2012 converts to the time point sequence 2012 day 1 through 2012 day 31 on the Gregorian days scale. 


shows that the intent is different from 'subdivides'.  'subdivides' is about converting January 2012 to the month-of-days; this is about converting it to a subsequence of 'day-of-year'.

But this takes us back to the idea above, that there are two different time point sequence ideas.  I think the 'converts to' idea is about locating the larger interval in a longer sequence of finer granularity intervals, as the large interval that is the hull of a subsequence, while 'subdivides' is about treating the larger time point as a sequence of consecutive time points that corresponds to sequences of consecutive smaller time intervals.  That is, 'converts to' is not about decomposing the time point and its corresponding time periods, it is about locating it in some other sequence; but subdivides is about decomposing the time point and its corresponding time periods.  

So I agree with Mark that 'subdivides' is not a special case of 'converts to', but we somehow have to be clear about the difference in intent in the definitions.  They both seem to say:  "time point on scale A is coextensive with time point sequence on scale B."  17227 is correct that that is what converts to means.  For 'subdivides' we have to talk about sequences of time intervals, somehow.

Regarding 17367: 
* I think that the OCL for the new axiom in 8.1.1 should read, as follows -- but need to consult the OCL book when I get home to be sure: 
OCL Constraint:        context: "time interval" 
                                   inv: "time interval"."time interval1 is proper part of time interval2"-->notEmpty() 

OK.  I will put that in the next draft, with a comment that says 'check this'.

* Why not wrap the new axiom in 8.1.6 into the definition of 'properly during'?  Why should it be a separate axiom? 
* I haven't provided the OCL for this new axiom because I think it instead should be a modification of the definitional OCL for 'properly during'. 

Well, 'properly during' is one of the Allen relations, and it is defined in terms of 'part of ' and 'before'.  'properly during' just says there is a proper part that is before it and one that is after it, which logically completes the partitioning of 'proper part': starts has no before, finishes has no after, and during has both.  What Mark suggests is that 'A is properly during B' could be defined as:  A is a proper part of B and there is a time interval C such that C starts B and C meets A, etc.  That does not clearly complete the partition.  To complete it, you would have to prove that:  If A does not start or finish B, then there is a C that starts B and meets A.   That is, if there is a C that is a proper part of B and is before A (i.e. A does not start B), then there is a C' that starts B and meets A.  And that is what the proposed axiom says, because you can't prove it from the other axioms.

In a similar way, the weak supplementation axiom says that for every proper part there is another proper part that does not overlap it.  So if A starts B, A has a supplement and the supplement must be after A.  But there is a 'start complement' axiom that says that if A starts B, there is a C that is met by A and finishes B -- the "maximal" supplement.  I don't think you can get these "maximal supplement" theorems from the axioms for 'part of' and 'before', precisely because we don't have strong supplementation:  If A is properly during B, then B-A is not a time interval.

* I think that what Fabian asked for is a different new axiom that says that every time interval has a proper part that starts/finishes it. 

Ah!  But those follow from the proposed axiom, together with the existing start-complement and finish-complement axioms.  E.g.
Theorem:  Every time interval has a proper part that starts it.
Proof:
If a time interval B has a proper part A, then (by the Allen partitioning), one of the following must be true: A starts B, A finishes B, A is properly during B.
Now, if A starts B, B has a proper part (A) that starts it.
If A finishes B, by the finish complement axiom, there is a C that starts B and meets A.  So B has a proper part (C) that starts it.
If A is during B, by the proposed axiom, there is a C that starts B and meets A.  So B has a proper part (C) that starts it.
So, if a time interval B has a proper part A, B has a proper part that starts B in all cases.  
By the no-smallest-interval axiom, every time interval B has some proper part A.  
So every time interval B has a proper part that starts B in all cases.  Q.E.D.
 
The nagging question is whether there might be a simpler solution than having these three complement axioms.  In particular, could we instead assert that every time interval has a proper part that starts it and a proper part that finishes it?  I think not, because there is no basis for relating an arbitrary starting part to an arbitrary finishing part.

-Ed

-- 
Edward J. Barkmeyer                        Email: edbark@nist.gov
National Institute of Standards & Technology
Manufacturing Systems Integration Division
100 Bureau Drive, Stop 8263                Tel: +1 301-975-3528
Gaithersburg, MD 20899-8263                Cel: +1 240-672-5800

"The opinions expressed above do not reflect consensus of NIST, 
and have not been reviewed by any Government authority." 



-------------------------------
Mark H. Linehan
STSM, IBM Research 



From:        Ed Barkmeyer <edbark@nist.gov> 
To:        OMG DateTimeVoc FTF <date-time-ftf@omg.org>, 
Date:        07/16/2012 07:23 PM 
Subject:        DTV Issues 16689, 16951, 17367 proposed resolutions 



--------------------------------------------------------------------------------



Per today's conference call, I attach the revised drafts for resolution 
of Issues
16689 - D0 should be quantified (added the UML object D0)
16951 - time point subdivision (see markup),
17367- no smallest time interval (1st draft, needs OCL)

For 16689, should we have defined a term like 'zero duration'?  Should 
that be the term and D0 the Synonym?

-Ed

-- 
Edward J. Barkmeyer                        Email: edbark@nist.gov
National Institute of Standards & Technology
Manufacturing Systems Integration Division
100 Bureau Drive, Stop 8263                Tel: +1 301-975-3528
Gaithersburg, MD 20899-8263                Cel: +1 240-672-5800



[attachment "DTV Issue 17367- no smallest time interval-d1.docx" deleted by Mark H Linehan/Watson/IBM] [attachment "DTV Issue 16689-D0 should be quantified.docx" deleted by Mark H Linehan/Watson/IBM] [attachment "DTV Issue 16951-time point subdivision-d4.doc" deleted by Mark H Linehan/Watson/IBM] 



To: date-time-ftf@omg.org, Stan@hendryxassoc.com
Subject: Re: DTV Issues 16689, 16951, 17367 proposed resolutions
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I think we basically agree.  My responses like this. 
--------------------------------
Mark H. Linehan
STSM, IBM Research 



From:        Ed Barkmeyer <edbark@nist.gov> 
To:        Mark H Linehan/Watson/IBM@IBMUS, 
Cc:        "date-time-ftf@omg.org" <date-time-ftf@omg.org>, Stan Hendryx <stan@hendryxassoc.com> 
Date:        07/27/2012 11:13 AM 
Subject:        Re: DTV Issues 16689, 16951, 17367 proposed resolutions 

--------------------------------------------------------------------------------





Mark H Linehan wrote: 
Ed, 

Regarding 16689:  Why isn't the  function (+ d1 d2) just a noun form of the predicate "duration3 = duration1 + duration2"? 

Noun-form of a verb is an SBVR idea that is misleading.  (I raised an issue on this in the first SBVR FTF, and it was swept under the rug.) In SBVR the instances of a verb concept are actualities, but the instances of the 'noun-form' of the verb are things that play roles in the actualities.  The "extensions" are not even of the same kind.  That is why I say the SBVR term is misleading.  The "noun-form" represents the 'function' concept, which is not a 'verb concept'.  It is a different, but related, concept.  And the two concepts are related by a definition such as the CLIF definition I gave.
[In classical formal logics, a predicate (verb concept) is a mapping from a tuple of things to true/false.  (Of course, Lowe and Zalta don't agree.)  And a function is a mapping from a tuple of things to a thing.  The SBVR 'noun form' is a function, as Mark pointed out.]

The real "noun form" of a verb concept is the gerund, or a noun that objectifies the verb, as defined in clause 11.  Those concepts have the same extension. 

I don't want to debate the concept or term 'noun form'.  My point is that the standard SBVR approach is to define "+d1 d2" as a synonymous form of "duration3 equals duration1 plus duration2".  Actually, I see we already have this synonymous form. 

Given that, the proposed CLIF doesn't say anything that isn't already implied by having the synonymous form.

Regarding 16951:  I don't think we need to distinguish "time point sequence" from "sequence of time points".  I think these are just two views of the same thing: either the time interval that corresponds to the convex hull of the whole time point sequence, or a sequence of time intervals that correspond to the individual time points of the time point sequence.  I think the two verb concepts ('subdivides' and 'converts to') are two different ways of using the one general concept. 


OK, but my point is that those two 'views' see technically different extensions of a time point sequence.  The whole point of subdivision is to decompose the time intervals, not to see them as one big interval.  subdivides decomposes an X into Ys, converts composes Ys into an X.


Yes, that's why I said one isn't a subtype of the other, but they are related.  I think we agree. 

Regarding how to define the time scales that irregularly subdivide time points, here's an example of what I suggest we should write: 

"Gregorian year of days scale: the finite time scale that subdivides âcommon yearâ into 365 of âGregorian day of yearâ and that subdivides 'leap year' into 366 of âGregorian day of yearâ. 


Yes.  I agree.


I don't think leap seconds have anything to do with this discussion.  Leap seconds involve displacing the UTC time scale, not adding seconds to calendar days.  BIPM is clear that 'day' is fixed at 86400 seconds. 


But the BIPM 'day' is a duration, a time unit.  A UTC day is a calendar day, and its length is variable, and the variation does not follow a named pattern like common year and leap year.  We don't cast 'leap seconds' as a kind of 'time offset' (from TAI to UTC), but that is what "displacing the UTC time scale" suggests.  It makes some sense.  The UTC rules are then rather like those of timezones -- some authority decides when to change from one time offset to another. We already have time offsets in hours and minutes; we could add seconds.  Is that a better approach than what we wrote?  


That's what we already decided and voted in issue 16680. Given that resolution, there's no reason to bring leap seconds into this "subdivides" discussion. 

Actually, I see that that resolution redefined the 'day of seconds scale' as "the finite time scale that subdivides each calendar day into at most 86 401 second of day".   So that resolution already started down the path of making these definitions acknowledge the varying number of x units in y time point.  Let's continue that. 

Regarding 17367: OK on adding the new axiom.  Here's the OCL, I think: 

OCL Definition:        context "time interval" 
                        inv: "time interval".allInstances-->forAll(t2 | 
                                       t2."is properly during"(self) 
                                                   implies "time interval".allInstances-->exists(t3 | 
                                                        t3.starts(self) and t3.meets(t2))) 
                        context "time interval" 
                        inv: "time interval".allInstances-->forAll(t2 | 
                                       t2." is properly during"(self) 
                                                   implies "time interval".allInstances-->exists(t3 | 
                                                        t3.ends(self) and t2.meets(t3))) 

I think we should make explicit the new axiom requested by Fabian. 


I agree.  I didn't realize I had not done that.

-Ed 
-- 
Edward J. Barkmeyer                        Email: edbark@nist.gov
National Institute of Standards & Technology
Manufacturing Systems Integration Division
100 Bureau Drive, Stop 8263                Tel: +1 301-975-3528
Gaithersburg, MD 20899-8263                Cel: +1 240-672-5800





--------------------------------
Mark H. Linehan
STSM, IBM Research 



From:        Ed Barkmeyer <edbark@nist.gov> 
To:        Mark H Linehan/Watson/IBM@IBMUS, 
Cc:        "date-time-ftf@omg.org" <date-time-ftf@omg.org>, Stan Hendryx <stan@hendryxassoc.com> 
Date:        07/26/2012 01:19 PM 
Subject:        Re: DTV Issues 16689, 16951, 17367 proposed resolutions 



--------------------------------------------------------------------------------





Mark H Linehan wrote: 
Regarding 16689: 
* I don't see the value of this CLIF axiom; it doesn't seem to say anything.  The one proposed to go after axiom V1 seems sufficient. 
CLIF Definition:        (forall ((d1 duration) (d2 duration) d3)
 (iff
   (= d3 (+ d1 d2))
   (and
     (duration d3)
     ("duration3 = duration1 + duration2"
        d3 d1 d2) ))) 

This axiom defines the function (+ d1 d2).  Otherwise it is primitive, and not clearly related to the predicate "duration3 = duration1 + duration2".  Or at least, I think that is the case.  The proposed axiom for V1 says that the function is defined everywhere:
(forall ((d1 duration) (d2 duration))
  (exists (d3 duration) 
    (= d3 (+ d1 d2)) )))
  
* I don't have a strong opinion about 'D0' versus 'zero duration'.  I don't see a lot of value in using the term 'zero duration' instead of 'D0'. 

In SBVR parlance, D0 is a symbol, 'zero duration' is a term.  Given that it is a term for something that is strictly a mathematical concept, it probably makes no difference.

Regarding 16951: 
* Editorial instruction #2 should make it clear that the new subsection has a regular section number, not the literal "9.4bis".  Something like "Immediately before clause 9.5, create a new subclause:", and renumber subclauses 9.5 and 9.6 as 9.6 and 9.7".  And then show "9.4bis" as "9.4". 

OK.

* I notice that all the uses of the 'subdivides' verb concept are of the form "<finite time scale> subdivides <time point> into <number> of <time point>".  Which makes me wonder whether the verb concept should have 4 roles rather than 2. 

Hmm.  I think the original verb was based on the idea that the subdivision was like hours and minutes -- the whole finite time scale.  But of course that was never true for month-of-days or year-of-days.  The subdivision really uses a time point sequence beginning with the origin index, which is what the proposed revised definition says.  But that 'time point sequence' idea may be wrong.  That is, I think a time point sequence is different from a sequence of time points, and 'subdivides' is about that difference.

Technically a sequence of time points corresponds to sequences of time intervals.  We say a 'time point sequence' corresponds to the one big interval that is the span (hull) of the sequence of intervals.  Now the 'one big interval' view is consistent with the idea that '2:00 to 4:00' indicates a time point sequence that corresponds to intervals that have a duration of two hours (or correctly 120 minutes).  But that is not what we mean by 'subdivides',  We mean treating the larger time point as a sequence of time points that corresponds to sequences of smaller time intervals, rather than to the hull of them.  This leads me to think that the term 'time point sequence' violates (Bernd Wenzel's) Law of Least Astonishment.  That is 'time point sequence' is not the same as 'sequence of time points'.

* There should be a Note that explains why we talk about a subsequence of the finite time scale.  The reason is that the subdivision of some kinds of time points into finite time scales is irregular.  Months are subdivided into 28-31 days and years are subdivided into 365 or 366 days. 

Agree.

* But, looking further, all of the uses of this verb concept talk about subdividing the "larger" time point into a fixed (not varying) number of "smaller" time points.  For example, the 'Gregorian year of days scale' is defined as "the finite time scale that subdivides âGregorian yearâ into 366 of âGregorian day of yearâ ".  Should it talk about subdividing leap years into 366 and common years into 365 'Gregorian day of year'?  Should the 'Gregorian month of days scale' be explicit about how it divides each of the Gregorian months?  What do we do about the 'year of weeks scale' since the number of weeks in a year is really messy? 

I guess we need to discuss this.  I agree with Mark's concern here, but I don't know what we want to write.  And <expletive deleted> leap seconds make minute-of-seconds or day-of-seconds truly variable.  

* The wording of the Necessity seems like something a logician would write not something that makes business sense.  The phrase "If a finite time scale subdivides a time point," should not be needed since the Necessity is in the context of this verb concept.  (In any case, this Necessity will be rewritten if my point about missing roles is accepted.) 

Yes.  This is part of the above.

* I agree that this verb concept is related to 'time point converts to time point sequence on time scale' but I don't agree that this verb concept is a 'special case' of the latter.  This verb concept is about the definitional relationship between finite time scales and time points; whereas the other is about computing the conversion. 

The Beta text of this verb concept is broken.  The replacement text from Issue 17227 says: 
Definition:                             the time point is coextensive with the time point sequence 

Necessity:                              Each time point of the time point sequence is on the time scale. 

Possibility:                             The time point is an absolute time point or is a relative time point. 

Description:                          The time point and the time point sequence are two different ways to identify the same time intervals. 


It doesn't say anything about computation.  The purpose is to provide meaning to the idea of computing the referents of a time coordinate, yes.  The Beta text indicated that intent -- it was trying to say that the decomposition into time points was about identifying time periods.  But the mechanism is said here to involve the conversion to an equivalent sequence of time points.  The example for 17227: 

Example:                                 The time point that is indicated by the time coordinate January 2012 converts to the time point sequence 2012 day 1 through 2012 day 31 on the Gregorian days scale. 


shows that the intent is different from 'subdivides'.  'subdivides' is about converting January 2012 to the month-of-days; this is about converting it to a subsequence of 'day-of-year'.

But this takes us back to the idea above, that there are two different time point sequence ideas.  I think the 'converts to' idea is about locating the larger interval in a longer sequence of finer granularity intervals, as the large interval that is the hull of a subsequence, while 'subdivides' is about treating the larger time point as a sequence of consecutive time points that corresponds to sequences of consecutive smaller time intervals.  That is, 'converts to' is not about decomposing the time point and its corresponding time periods, it is about locating it in some other sequence; but subdivides is about decomposing the time point and its corresponding time periods.  

So I agree with Mark that 'subdivides' is not a special case of 'converts to', but we somehow have to be clear about the difference in intent in the definitions.  They both seem to say:  "time point on scale A is coextensive with time point sequence on scale B."  17227 is correct that that is what converts to means.  For 'subdivides' we have to talk about sequences of time intervals, somehow.

Regarding 17367: 
* I think that the OCL for the new axiom in 8.1.1 should read, as follows -- but need to consult the OCL book when I get home to be sure: 
OCL Constraint:        context: "time interval" 
                                   inv: "time interval"."time interval1 is proper part of time interval2"-->notEmpty() 

OK.  I will put that in the next draft, with a comment that says 'check this'.

* Why not wrap the new axiom in 8.1.6 into the definition of 'properly during'?  Why should it be a separate axiom? 
* I haven't provided the OCL for this new axiom because I think it instead should be a modification of the definitional OCL for 'properly during'. 

Well, 'properly during' is one of the Allen relations, and it is defined in terms of 'part of ' and 'before'.  'properly during' just says there is a proper part that is before it and one that is after it, which logically completes the partitioning of 'proper part': starts has no before, finishes has no after, and during has both.  What Mark suggests is that 'A is properly during B' could be defined as:  A is a proper part of B and there is a time interval C such that C starts B and C meets A, etc.  That does not clearly complete the partition.  To complete it, you would have to prove that:  If A does not start or finish B, then there is a C that starts B and meets A.   That is, if there is a C that is a proper part of B and is before A (i.e. A does not start B), then there is a C' that starts B and meets A.  And that is what the proposed axiom says, because you can't prove it from the other axioms.

In a similar way, the weak supplementation axiom says that for every proper part there is another proper part that does not overlap it.  So if A starts B, A has a supplement and the supplement must be after A.  But there is a 'start complement' axiom that says that if A starts B, there is a C that is met by A and finishes B -- the "maximal" supplement.  I don't think you can get these "maximal supplement" theorems from the axioms for 'part of' and 'before', precisely because we don't have strong supplementation:  If A is properly during B, then B-A is not a time interval.

* I think that what Fabian asked for is a different new axiom that says that every time interval has a proper part that starts/finishes it. 

Ah!  But those follow from the proposed axiom, together with the existing start-complement and finish-complement axioms.  E.g.
Theorem:  Every time interval has a proper part that starts it.
Proof:
If a time interval B has a proper part A, then (by the Allen partitioning), one of the following must be true: A starts B, A finishes B, A is properly during B.
Now, if A starts B, B has a proper part (A) that starts it.
If A finishes B, by the finish complement axiom, there is a C that starts B and meets A.  So B has a proper part (C) that starts it.
If A is during B, by the proposed axiom, there is a C that starts B and meets A.  So B has a proper part (C) that starts it.
So, if a time interval B has a proper part A, B has a proper part that starts B in all cases.  
By the no-smallest-interval axiom, every time interval B has some proper part A.  
So every time interval B has a proper part that starts B in all cases.  Q.E.D.
 
The nagging question is whether there might be a simpler solution than having these three complement axioms.  In particular, could we instead assert that every time interval has a proper part that starts it and a proper part that finishes it?  I think not, because there is no basis for relating an arbitrary starting part to an arbitrary finishing part.

-Ed

-- 
Edward J. Barkmeyer                        Email: edbark@nist.gov
National Institute of Standards & Technology
Manufacturing Systems Integration Division
100 Bureau Drive, Stop 8263                Tel: +1 301-975-3528
Gaithersburg, MD 20899-8263                Cel: +1 240-672-5800

"The opinions expressed above do not reflect consensus of NIST, 
and have not been reviewed by any Government authority." 



-------------------------------
Mark H. Linehan
STSM, IBM Research 



From:        Ed Barkmeyer <edbark@nist.gov> 
To:        OMG DateTimeVoc FTF <date-time-ftf@omg.org>, 
Date:        07/16/2012 07:23 PM 
Subject:        DTV Issues 16689, 16951, 17367 proposed resolutions 



--------------------------------------------------------------------------------



Per today's conference call, I attach the revised drafts for resolution 
of Issues
16689 - D0 should be quantified (added the UML object D0)
16951 - time point subdivision (see markup),
17367- no smallest time interval (1st draft, needs OCL)

For 16689, should we have defined a term like 'zero duration'?  Should 
that be the term and D0 the Synonym?

-Ed

-- 
Edward J. Barkmeyer                        Email: edbark@nist.gov
National Institute of Standards & Technology
Manufacturing Systems Integration Division
100 Bureau Drive, Stop 8263                Tel: +1 301-975-3528
Gaithersburg, MD 20899-8263                Cel: +1 240-672-5800



[attachment "DTV Issue 17367- no smallest time interval-d1.docx" deleted by Mark H Linehan/Watson/IBM] [attachment "DTV Issue 16689-D0 should be quantified.docx" deleted by Mark H Linehan/Watson/IBM] [attachment "DTV Issue 16951-time point subdivision-d4.doc" deleted by Mark H Linehan/Watson/IBM] 


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I attach the revised version of Issue 17367, incorporating the agreements.  (I didn't have change tracking on.  I added Mark's OCL and Fabian's corollaries.)

I attach a slightly revised version of 16689.  I hope we are done with this.

I need to do more work on 16951.

Mark H Linehan wrote:

Regarding 16689:  Why isn't the  function (+ d1 d2) just a noun form of the predicate "duration3 = duration1 + duration2"? 
...
My point is that the standard SBVR approach is to define "+d1 d2" as a synonymous form of "duration3 equals duration1 plus duration2".  Actually, I see we already have this synonymous form. 

Given that, the proposed CLIF doesn't say anything that isn't already implied by having the synonymous form.


Well, perhaps the function is implied by the predicate in SBVR, but in CLIF they are unrelated symbols unless we relate them.  In the same way, defining the association in the UML model doesn't define the operation.  That is all this does.  You have to read the CLIF to say: d3 is (+ d1 d2) exactly when ("duration3 equals duration1 plus duration2" d3 d1 d2).  (In a reasoner, one would "skolemize" the thing named (+ d1 d2) by inventing a d3 to be the result, i.e., (exists (d3))(= d3 (+ d1 d2)), and then this definition axiom turns "d3 =  structured name" into a proposition involving d1, d2, and d3.)


Regarding 16951:  I don't think we need to distinguish "time point sequence" from "sequence of time points".  I think these are just two views of the same thing: either the time interval that corresponds to the convex hull of the whole time point sequence, or a sequence of time intervals that correspond to the individual time points of the time point sequence.  I think the two verb concepts ('subdivides' and 'converts to') are two different ways of using the one general concept. 

EJB
OK, but my point is that those two 'views' see technically different extensions of a time point sequence.  The whole point of subdivision is to decompose the time intervals, not to see them as one big interval.  subdivides decomposes an X into Ys, converts composes Ys into an X.


MHL: Yes, that's why I said one isn't a subtype of the other, but they are related.  I think we agree.


Yes, we agree on that.  I am still a bit worried about what the extension of a time point sequence is.  The convex hull is in some sense equivalent to the sequence of component intervals, but it is not the same thing.
.  


MHL

I don't think leap seconds have anything to do with this discussion.  Leap seconds involve displacing the UTC time scale, not adding seconds to calendar days.  BIPM is clear that 'day' is fixed at 86400 seconds. 

EJB
But the BIPM 'day' is a duration, a time unit.  A UTC day is a calendar day, and its length is variable, and the variation does not follow a named pattern like common year and leap year.  We don't cast 'leap seconds' as a kind of 'time offset' (from TAI to UTC), but that is what "displacing the UTC time scale" suggests.  It makes some sense.  The UTC rules are then rather like those of timezones -- some authority decides when to change from one time offset to another. We already have time offsets in hours and minutes; we could add seconds.  Is that a better approach than what we wrote?  


MHL
That's what we already decided and voted in issue 16680. Given that resolution, there's no reason to bring leap seconds into this "subdivides" discussion. 

Actually, I see that that resolution redefined the 'day of seconds scale' as "the finite time scale that subdivides each calendar day into at most 86 401 second of day".   So that resolution already started down the path of making these definitions acknowledge the varying number of x units in y time point.  Let's continue that.


What we agreed to in 16680 is NOT to describe leap seconds as time offsets, but rather to agree that there are minutes of different lengths and days of different lengths.  Describing 'leap seconds' as time offsets is very different:  Every clock minute would be subdivided into exactly 60 seconds, and every calendar day into exactly 86400 seconds.  But every time UTC adds a leap second we use a different calendar with a different time offset from TAI.  In the same way, the US Eastern Time Zone does not have variable length days, it just sometimes uses the EST offset and sometimes uses the EDT offset.  This affects the duration of a 'day period', but not a calendar day.  What I am suggesting is that UTC is several different calendars with different time offsets from TAI -- each leap second they add defines a new calendar with a different time offset: "UTC as of <datetime>".

If we adopt that view of leap seconds, we can do what you suggest about the subdivisions:  common years and leap years have different subdivisions, March and April have different subdivisions, but none of them is variable.  Leap seconds are the only things that create truly variable subdivisions, and if we switch to a time offset model of leap seconds, the variable subdivisions disappear entirely. 






--------------------------------
Mark H. Linehan
STSM, IBM Research 



From:        Ed Barkmeyer <edbark@nist.gov> 
To:        Mark H Linehan/Watson/IBM@IBMUS, 
Cc:        "date-time-ftf@omg.org" <date-time-ftf@omg.org>, Stan Hendryx <stan@hendryxassoc.com> 
Date:        07/26/2012 01:19 PM 
Subject:        Re: DTV Issues 16689, 16951, 17367 proposed resolutions 



--------------------------------------------------------------------------------





Mark H Linehan wrote: 
Regarding 16689: 
* I don't see the value of this CLIF axiom; it doesn't seem to say anything.  The one proposed to go after axiom V1 seems sufficient. 
CLIF Definition:        (forall ((d1 duration) (d2 duration) d3)
 (iff
   (= d3 (+ d1 d2))
   (and
     (duration d3)
     ("duration3 = duration1 + duration2"
        d3 d1 d2) ))) 

This axiom defines the function (+ d1 d2).  Otherwise it is primitive, and not clearly related to the predicate "duration3 = duration1 + duration2".  Or at least, I think that is the case.  The proposed axiom for V1 says that the function is defined everywhere:
(forall ((d1 duration) (d2 duration))
  (exists (d3 duration) 
    (= d3 (+ d1 d2)) )))
  
* I don't have a strong opinion about 'D0' versus 'zero duration'.  I don't see a lot of value in using the term 'zero duration' instead of 'D0'. 

In SBVR parlance, D0 is a symbol, 'zero duration' is a term.  Given that it is a term for something that is strictly a mathematical concept, it probably makes no difference.

Regarding 16951: 
* Editorial instruction #2 should make it clear that the new subsection has a regular section number, not the literal "9.4bis".  Something like "Immediately before clause 9.5, create a new subclause:", and renumber subclauses 9.5 and 9.6 as 9.6 and 9.7".  And then show "9.4bis" as "9.4". 

OK.

* I notice that all the uses of the 'subdivides' verb concept are of the form "<finite time scale> subdivides <time point> into <number> of <time point>".  Which makes me wonder whether the verb concept should have 4 roles rather than 2. 

Hmm.  I think the original verb was based on the idea that the subdivision was like hours and minutes -- the whole finite time scale.  But of course that was never true for month-of-days or year-of-days.  The subdivision really uses a time point sequence beginning with the origin index, which is what the proposed revised definition says.  But that 'time point sequence' idea may be wrong.  That is, I think a time point sequence is different from a sequence of time points, and 'subdivides' is about that difference.

Technically a sequence of time points corresponds to sequences of time intervals.  We say a 'time point sequence' corresponds to the one big interval that is the span (hull) of the sequence of intervals.  Now the 'one big interval' view is consistent with the idea that '2:00 to 4:00' indicates a time point sequence that corresponds to intervals that have a duration of two hours (or correctly 120 minutes).  But that is not what we mean by 'subdivides',  We mean treating the larger time point as a sequence of time points that corresponds to sequences of smaller time intervals, rather than to the hull of them.  This leads me to think that the term 'time point sequence' violates (Bernd Wenzel's) Law of Least Astonishment.  That is 'time point sequence' is not the same as 'sequence of time points'.

* There should be a Note that explains why we talk about a subsequence of the finite time scale.  The reason is that the subdivision of some kinds of time points into finite time scales is irregular.  Months are subdivided into 28-31 days and years are subdivided into 365 or 366 days. 

Agree.

* But, looking further, all of the uses of this verb concept talk about subdividing the "larger" time point into a fixed (not varying) number of "smaller" time points.  For example, the 'Gregorian year of days scale' is defined as "the finite time scale that subdivides .Gregorian year. into 366 of .Gregorian day of year. ".  Should it talk about subdividing leap years into 366 and common years into 365 'Gregorian day of year'?  Should the 'Gregorian month of days scale' be explicit about how it divides each of the Gregorian months?  What do we do about the 'year of weeks scale' since the number of weeks in a year is really messy? 

I guess we need to discuss this.  I agree with Mark's concern here, but I don't know what we want to write.  And <expletive deleted> leap seconds make minute-of-seconds or day-of-seconds truly variable.  

* The wording of the Necessity seems like something a logician would write not something that makes business sense.  The phrase "If a finite time scale subdivides a time point," should not be needed since the Necessity is in the context of this verb concept.  (In any case, this Necessity will be rewritten if my point about missing roles is accepted.) 

Yes.  This is part of the above.

* I agree that this verb concept is related to 'time point converts to time point sequence on time scale' but I don't agree that this verb concept is a 'special case' of the latter.  This verb concept is about the definitional relationship between finite time scales and time points; whereas the other is about computing the conversion. 

The Beta text of this verb concept is broken.  The replacement text from Issue 17227 says: 
Definition:                             the time point is coextensive with the time point sequence 

Necessity:                              Each time point of the time point sequence is on the time scale. 

Possibility:                             The time point is an absolute time point or is a relative time point. 

Description:                          The time point and the time point sequence are two different ways to identify the same time intervals. 


It doesn't say anything about computation.  The purpose is to provide meaning to the idea of computing the referents of a time coordinate, yes.  The Beta text indicated that intent -- it was trying to say that the decomposition into time points was about identifying time periods.  But the mechanism is said here to involve the conversion to an equivalent sequence of time points.  The example for 17227: 

Example:                                 The time point that is indicated by the time coordinate January 2012 converts to the time point sequence 2012 day 1 through 2012 day 31 on the Gregorian days scale. 


shows that the intent is different from 'subdivides'.  'subdivides' is about converting January 2012 to the month-of-days; this is about converting it to a subsequence of 'day-of-year'.

But this takes us back to the idea above, that there are two different time point sequence ideas.  I think the 'converts to' idea is about locating the larger interval in a longer sequence of finer granularity intervals, as the large interval that is the hull of a subsequence, while 'subdivides' is about treating the larger time point as a sequence of consecutive time points that corresponds to sequences of consecutive smaller time intervals.  That is, 'converts to' is not about decomposing the time point and its corresponding time periods, it is about locating it in some other sequence; but subdivides is about decomposing the time point and its corresponding time periods.  

So I agree with Mark that 'subdivides' is not a special case of 'converts to', but we somehow have to be clear about the difference in intent in the definitions.  They both seem to say:  "time point on scale A is coextensive with time point sequence on scale B."  17227 is correct that that is what converts to means.  For 'subdivides' we have to talk about sequences of time intervals, somehow.

Regarding 17367: 
* I think that the OCL for the new axiom in 8.1.1 should read, as follows -- but need to consult the OCL book when I get home to be sure: 
OCL Constraint:        context: "time interval" 
                                   inv: "time interval"."time interval1 is proper part of time interval2"-->notEmpty() 

OK.  I will put that in the next draft, with a comment that says 'check this'.

* Why not wrap the new axiom in 8.1.6 into the definition of 'properly during'?  Why should it be a separate axiom? 
* I haven't provided the OCL for this new axiom because I think it instead should be a modification of the definitional OCL for 'properly during'. 

Well, 'properly during' is one of the Allen relations, and it is defined in terms of 'part of ' and 'before'.  'properly during' just says there is a proper part that is before it and one that is after it, which logically completes the partitioning of 'proper part': starts has no before, finishes has no after, and during has both.  What Mark suggests is that 'A is properly during B' could be defined as:  A is a proper part of B and there is a time interval C such that C starts B and C meets A, etc.  That does not clearly complete the partition.  To complete it, you would have to prove that:  If A does not start or finish B, then there is a C that starts B and meets A.   That is, if there is a C that is a proper part of B and is before A (i.e. A does not start B), then there is a C' that starts B and meets A.  And that is what the proposed axiom says, because you can't prove it from the other axioms.

In a similar way, the weak supplementation axiom says that for every proper part there is another proper part that does not overlap it.  So if A starts B, A has a supplement and the supplement must be after A.  But there is a 'start complement' axiom that says that if A starts B, there is a C that is met by A and finishes B -- the "maximal" supplement.  I don't think you can get these "maximal supplement" theorems from the axioms for 'part of' and 'before', precisely because we don't have strong supplementation:  If A is properly during B, then B-A is not a time interval.

* I think that what Fabian asked for is a different new axiom that says that every time interval has a proper part that starts/finishes it. 

Ah!  But those follow from the proposed axiom, together with the existing start-complement and finish-complement axioms.  E.g.
Theorem:  Every time interval has a proper part that starts it.
Proof:
If a time interval B has a proper part A, then (by the Allen partitioning), one of the following must be true: A starts B, A finishes B, A is properly during B.
Now, if A starts B, B has a proper part (A) that starts it.
If A finishes B, by the finish complement axiom, there is a C that starts B and meets A.  So B has a proper part (C) that starts it.
If A is during B, by the proposed axiom, there is a C that starts B and meets A.  So B has a proper part (C) that starts it.
So, if a time interval B has a proper part A, B has a proper part that starts B in all cases.  
By the no-smallest-interval axiom, every time interval B has some proper part A.  
So every time interval B has a proper part that starts B in all cases.  Q.E.D.
 
The nagging question is whether there might be a simpler solution than having these three complement axioms.  In particular, could we instead assert that every time interval has a proper part that starts it and a proper part that finishes it?  I think not, because there is no basis for relating an arbitrary starting part to an arbitrary finishing part.

-Ed

-- 
Edward J. Barkmeyer                        Email: edbark@nist.gov
National Institute of Standards & Technology
Manufacturing Systems Integration Division
100 Bureau Drive, Stop 8263                Tel: +1 301-975-3528
Gaithersburg, MD 20899-8263                Cel: +1 240-672-5800

"The opinions expressed above do not reflect consensus of NIST, 
and have not been reviewed by any Government authority." 



-------------------------------
Mark H. Linehan
STSM, IBM Research 



From:        Ed Barkmeyer <edbark@nist.gov> 
To:        OMG DateTimeVoc FTF <date-time-ftf@omg.org>, 
Date:        07/16/2012 07:23 PM 
Subject:        DTV Issues 16689, 16951, 17367 proposed resolutions 



--------------------------------------------------------------------------------



Per today's conference call, I attach the revised drafts for resolution 
of Issues
16689 - D0 should be quantified (added the UML object D0)
16951 - time point subdivision (see markup),
17367- no smallest time interval (1st draft, needs OCL)

For 16689, should we have defined a term like 'zero duration'?  Should 
that be the term and D0 the Synonym?

-Ed

-- 
Edward J. Barkmeyer                        Email: edbark@nist.gov
National Institute of Standards & Technology
Manufacturing Systems Integration Division
100 Bureau Drive, Stop 8263                Tel: +1 301-975-3528
Gaithersburg, MD 20899-8263                Cel: +1 240-672-5800



[attachment "DTV Issue 17367- no smallest time interval-d1.docx" deleted by Mark H Linehan/Watson/IBM] [attachment "DTV Issue 16689-D0 should be quantified.docx" deleted by Mark H Linehan/Watson/IBM] [attachment "DTV Issue 16951-time point subdivision-d4.doc" deleted by Mark H Linehan/Watson/IBM] 





-- 
Edward J. Barkmeyer                        Email: edbark@nist.gov
National Institute of Standards & Technology
Manufacturing Systems Integration Division
100 Bureau Drive, Stop 8263                Tel: +1 301-975-3528
Gaithersburg, MD 20899-8263                Cel: +1 240-672-5800





 DTV Issue 17367- no smallest time interval-d2.docx 


 DTV Issue 16689-D0 should be quantified-d2.docx 




Date: Mon, 30 Jul 2012 18:26:51 -0400
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One step forward and two steps back.  I attach yet another revision.
This one uses Mark's proposed rework of the verb concept wording, and it opens a new can of worms -- intensional roles.  So we need to decide about this wording.


I think we are agreed on the issue of the relationship to 'time point sequence' and to 'time point converts to time point sequence'.  The writeup may still need editing.


The problem with subdivision from day 1 is that we have all understood the intent, but formalizing it is tricky.


-Ed


-- 
Edward J. Barkmeyer                        Email: edbark@nist.gov
National Institute of Standards & Technology
Manufacturing Systems Integration Division
100 Bureau Drive, Stop 8263                Tel: +1 301-975-3528
Gaithersburg, MD 20899-8263                Cel: +1 240-672-5800


"The opinions expressed above do not reflect consensus of NIST, and have not been reviewed by any Government authority."





 DTV Issue 16951-time point subdivision-d5.doc <Down>
<Down>
<Down>
Disposition: Resolved
OMG Issue No:  16951 
Title:	Time point subdivision is out of place twice
Source: Ed Barkmeyer, NIST, edbark@nist.gov

Summary:
At the end of section 9.3 the fact type 'finite time scale subdivides time point' is defined and depicted in Figure 9-6.  This fact type is a commonly used property of finite time scales, and is not specific to individual time points.  That is, the finite time scale day-of-hours subdivides every day-of-month, for example.  So the text and diagram should be at the end of 9.2, where finite time scale is defined. 
Also, diagram 9-6 does not show the operations on time point and finite time scale that are associated with this fact type and shown in diagram 12-12.
Finally, diagram 12-12 (section 12.4) shows this fact type as well, but section 12.4 never uses it, and diagram 12-12 shows a <<specialization>> relationship that is never discussed anywhere in the text.  If the relationship is important, it should be discussed.  Otherwise, the subdivision association is out of place in diagram 12-12 and the "specialization" dependency should be deleted from the UML model.
Recommendation: Move the diagram and text for 'finite time scale subdivides time point' to the end of 9.2, include the operations on the diagram.  Delete the fact type from diagram 12-12, and delete the "specialization" dependency altogether.
Resolution:
The FTF agrees that the fact-type 'finite time scale subdivides time point' should be moved, along with Figure 9-6, but it depends on concepts defined in 9.3 and 9.4. It is an important concept that should have its own subsection.
The definition in 9.3 is inaccurate.  What is meant is that the corresponding time intervals are subdivided into intervals that the relative time points of the finite time scale correspond to.  
The concept should not appear in diagram 12-12. The "specialization" dependency should be deleted entirely. The intent is that this is a special case of 'time point converts to time point sequence on time scale', and that should be mentioned in a Note.
Revised Text:
1.  At the end of 9.3, DELETE the Figure 9.6 and the following text:
(Figure 9.6)
Figure 9.6: Time Scale Subdivision
finite time scale subdivides time point
Definition:	the finite time scale divides the time point into a number of time intervals that each have a duration, and the number is the cardinality of the finite time scale, and the duration is the granularity of the finite time scale
Example:	The day of hours scale subdivides the Gregorian date 3 January 2010 into 24 time intervals, each of duration "hour"

2.  Immediately before section 9.5, create a new subsection numbered 9.5, and renumber the subsequent sections: 
9.4bis 5 Time Point Subdivision
The purpose of finite time scales is to provide finer-grained resolution of time intervals within the time intervals that are instances of time points with coarser granularities.  In this specification the relationship between a finite time scale and a coarser time point is called .time point subdivision..  Many finite time scales are defined by the category of time point they subdivide and the granularity of the time points they contain.
 
Figure 9.x: Time Scale Subdivision 
finite time scale subdivides time point1  into number of time point2*
Definition:	the finite time scale divides the time point1 into a regular sequence of time point2  sequence that is a subsequence of the finite time scale and, that includes the index origin member of the finite time scale, and that implicitly divides each time interval that the time point1 corresponds to into a consecutive sequence of time intervals, such that each time point2 of in the sequence of time point2 sequence corresponds to exactly one of the time intervals.
Necessity:	If a finite time scale subdivides a time point1 into some number of time point2, each time point on the finite time scale is an instance of time point2.
Note:	The asterisk after time point2 indicates that the role is an .intensional role. (per SBVR Annex C.1.6), that is, the role is played by a kind of time point, rather than by a time point. 
Necessity:	If a finite time scale subdivides a time point1 into some number of time point2time point, there is a time point sequence such that  
  the time point sequence is on the finite time scale, and
  the first time point of the time point sequence is the index origin member of the finite time scale, and
  the cardinality of the time point sequence is the number, and
  the time point sequence corresponds to each time interval that is an instance of the time point1, and
  each time interval that the time point corresponds to is equal to the cardinality of the time point sequence times the granularity of the finite time scale.  
Note:	The definition says that the subdivision of time point1 is a regular sequence of time points on the finite time scale.  The Necessity above says that that regular sequence forms a time point sequence that corresponds to the same time intervals that time point1 does.  The principal concept of the subdivision, however, is that the individual members of the regular sequence . the time points on the finite time scale . correspond to sub-intervals of those time intervals.
Example:	The day of hours scale subdivides Gregorian date 3 January 2010 into 24 hour of day time points, and implicitly divides the time interval corresponding to Gregorian date 3 January 2010 into 24 time intervals, each of which corresponds to is an instance of one hour-of-day.
Note:	A finite time scale is a time point sequence (see 9.3) and the subdivision of a time point is a special case of time point converts to time point sequence on time scale (see 12.4).  
Note:	A regular sequence of time points on a finite time scale makes up a time point sequence (see 9.3).   So, finite time scale subdivides time point superficially resembles time point converts to time point sequence on time scale (see 12.4).  The difference is this: finite time scale subdivides time point uses the time point and the finite time scale to define smaller time intervals with relative time coordinates (see 12.1.1).  time point converts to time point sequence on time scale relates the time point to a subsequence of a time scale that covers a longer span of time. 

[Editorial Note: Diagram 12-12 is modified by other issues.] 

Disposition:	Resolved

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The design looks fine to me.  I tried to simplify the wording in this version: 

The use of an intentional role looks right to me. 

What about updating the definitions of the 'Gregorian year of days scale' and the 'Gregorian month of days scale'? 
--------------------------------
Mark H. Linehan
STSM, IBM Research 



From:        Ed Barkmeyer <edbark@nist.gov> 
To:        OMG DateTimeVoc FTF <date-time-ftf@omg.org>, 
Date:        07/30/2012 06:29 PM 
Subject:        DTV Issue 16951 - Time point subdivision 

--------------------------------------------------------------------------------



One step forward and two steps back.  I attach yet another revision.
This one uses Mark's proposed rework of the verb concept wording, and it 
opens a new can of worms -- intensional roles.  So we need to decide 
about this wording.

I think we are agreed on the issue of the relationship to 'time point 
sequence' and to 'time point converts to time point sequence'.  The 
writeup may still need editing.

The problem with subdivision from day 1 is that we have all understood 
the intent, but formalizing it is tricky.

-Ed

-- 
Edward J. Barkmeyer                        Email: edbark@nist.gov
National Institute of Standards & Technology
Manufacturing Systems Integration Division
100 Bureau Drive, Stop 8263                Tel: +1 301-975-3528
Gaithersburg, MD 20899-8263                Cel: +1 240-672-5800

"The opinions expressed above do not reflect consensus of NIST, 
and have not been reviewed by any Government authority."

[attachment "DTV Issue 16951-time point subdivision-d5.doc" deleted by Mark H Linehan/Watson/IBM] 


 Date-Time Issue 16951- time point subdivision is out of place twice.doc <Down>
<Down>
	Disposition: Resolved
	OMG Issue No:  16951 
Title:	Time point subdivision is out of place twice
Source: Ed Barkmeyer, NIST, edbark@nist.gov

Summary:
At the end of section 9.3 the fact type 'finite time scale subdivides time point' is defined and depicted in Figure 9-6.  This fact type is a commonly used property of finite time scales, and is not specific to individual time points.  That is, the finite time scale day-of-hours subdivides every day-of-month, for example.  So the text and diagram should be at the end of 9.2, where finite time scale is defined. 
Also, diagram 9-6 does not show the operations on time point and finite time scale that are associated with this fact type and shown in diagram 12-12.
Finally, diagram 12-12 (section 12.4) shows this fact type as well, but section 12.4 never uses it, and diagram 12-12 shows a <<specialization>> relationship that is never discussed anywhere in the text.  If the relationship is important, it should be discussed.  Otherwise, the subdivision association is out of place in diagram 12-12 and the "specialization" dependency should be deleted from the UML model.
Recommendation: Move the diagram and text for 'finite time scale subdivides time point' to the end of 9.2, include the operations on the diagram.  Delete the fact type from diagram 12-12, and delete the "specialization" dependency altogether.
Resolution:
The FTF agrees that the fact-type 'finite time scale subdivides time point' should be moved, along with Figure 9-6, but it depends on concepts defined in 9.3 and 9.4. It is an important concept that should have its own subsection.
The definition in 9.3 is inaccurate.  What is meant is that the corresponding time intervals are subdivided into intervals that the relative time points of the finite time scale correspond to.  
The concept should not appear in diagram 12-12. The "specialization" dependency should be deleted entirely. The intent is that this is a special case of 'time point converts to time point sequence on time scale', and that should be mentioned in a Note.
Revised Text:
1.  At the end of 9.3, DELETE the Figure 9.6 and the following text:
(Figure 9.6)
Figure 9.6: Time Scale Subdivision
finite time scale subdivides time point
Definition:	the finite time scale divides the time point into a number of time intervals that each have a duration, and the number is the cardinality of the finite time scale, and the duration is the granularity of the finite time scale
Example:	The day of hours scale subdivides the Gregorian date 3 January 2010 into 24 time intervals, each of duration "hour"

2.  Immediately before section 9.5, create a new subsection numbered 9.5, and renumber the subsequent sections: 
9.4bis 5 Time Point Subdivision
The purpose of finite time scales is to provide finer-grained resolution of time intervals within the time intervals that are instances of time points with coarser granularities.  In this specification the relationship between a finite time scale and a coarser time point is called .time point subdivision..  Many finite time scales are defined by the category of time point they subdivide and the granularity of the time points they contain.
 
Figure 9.x: Time Scale Subdivision 
finite time scale subdivides time point1  into number of time point2*
Definition:	the finite time scale divides the time point1 into a regular sequence1 of time point2  sequence that is a subsequence of the finite time scale and, that includes the index origin member of the finite time scale, and that implicitly divides each time interval that the time point1 corresponds to into a consecutiveregular  sequence2 of time intervals, such that and each time point2 of inof the regular sequence1sequence of time point2 sequence corresponds to exactly one of the time intervals and the cardinality of regular sequence1 is the number.
Necessity:	If a finite time scale subdivides a time point1 into some number of time point2, eEach time point on the finite time scale is an instance of time point2.
Note:	The asterisk after time point2 indicates that the role is an .intensional role. (per SBVR Annex C.1.6), that is, the role is played by a kind of time point, rather than by a time point instance. 
Necessity:	If a finite time scale subdivides a time point1 into some number of time point2time point, there is a time point sequence such that   
  the time point sequence is on the finite time scale, and
  the first time point of the time point sequence is the index origin member of the finite time scale, and
  the cardinality of the time point sequence is the number, and
  the time point sequence corresponds to each time interval that is an instance of the time point1, and
  each time interval that the time point corresponds to is equal to the cardinality of the time point sequence times the granularity of the finite time scale.  
	The  definition says that the subdivision of time point1 is a regular sequence of time points on the finite time scale.  The Necessity above says that that regular sequence forms a time point sequence that corresponds to the same time intervals that time point1 does.  The principal concept of the subdivision, however, is that the individual members of the regular sequence . the time points on the finite time scale . correspond to sub-intervals of those time intervals.
Example:	The day of hours scale subdivides Gregorian date 3 January 2010 into 24 hour of day time points, and implicitly divides the time interval corresponding to Gregorian date 3 January 2010 into 24 time intervals, each of which corresponds to is an instance of one hour-of-day.
Note:	A finite time scale is a time point sequence (see 9.3) and the subdivision of a time point is a special case of time point converts to time point sequence on time scale (see 12.4).  
Note:	A regular sequence of time points on a finite time scale makes up a time point sequence (see 9.3).   So, finite time scale subdivides time point superficially resembles time point converts to time point sequence on time scale (see 12.4).  The difference is this: finite time scale subdivides time point uses the time point and the finite time scale to define smaller time intervals with relative time coordinates (see 12.1.1).  time point converts to time point sequence on time scale relates the time point to a subsequence of a time scale that covers a longer span of time. 

[Editorial Note: Diagram 12-12 is modified by other issues.] 

Disposition:	Resolved

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Subject: Re: DTV Issue 16951 - Time point subdivision
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I modified Mark's markup in one substantive way.  See the comment about "consecutive time intervals".
I don't object to deleting the Necessity about the time point sequence equivalent, but it is not the Definition -- it is formal, and the definition does not say anything about time point sequences (which is what converts to is about).

More importantly, I am still uncomfortable using the 'intensional role' in the verb concept wording.

The rest is just editorial disagreement.  

I understand that business people don't say 'such that', but they say things like "where" or "with the following properties", and SBVR Annex C does not include those expressions, either.  I would be happy with "where", but business people also use "where" to talk about locations, and Annex C suggests that that might also be valid SBVR SE.  The question is:  How does one phrase 'the following statements about the things in these roles are true", when the subjects of the verbs in those statements are different?  The 'such that' appears in a Necessity that states the existence of a time point sequence with 4 characteristics that involve different properties of it.

-Ed



-- 
Edward J. Barkmeyer                        Email: edbark@nist.gov
National Institute of Standards & Technology
Manufacturing Systems Integration Division
100 Bureau Drive, Stop 8263                Tel: +1 301-975-3528
Gaithersburg, MD 20899-8263                Cel: +1 240-672-5800

"The opinions expressed above do not reflect consensus of NIST, 
 and have not been reviewed by any Government authority."


Mark H Linehan wrote: 
The design looks fine to me.  I tried to simplify the wording in this version: 

The use of an intentional role looks right to me. 

What about updating the definitions of the 'Gregorian year of days scale' and the 'Gregorian month of days scale'? 
--------------------------------
Mark H. Linehan
STSM, IBM Research 



From:        Ed Barkmeyer <edbark@nist.gov> 
To:        OMG DateTimeVoc FTF <date-time-ftf@omg.org>, 
Date:        07/30/2012 06:29 PM 
Subject:        DTV Issue 16951 - Time point subdivision 

--------------------------------------------------------------------------------



One step forward and two steps back.  I attach yet another revision.
This one uses Mark's proposed rework of the verb concept wording, and it 
opens a new can of worms -- intensional roles.  So we need to decide 
about this wording.

I think we are agreed on the issue of the relationship to 'time point 
sequence' and to 'time point converts to time point sequence'.  The 
writeup may still need editing.

The problem with subdivision from day 1 is that we have all understood 
the intent, but formalizing it is tricky.

-Ed

-- 
Edward J. Barkmeyer                        Email: edbark@nist.gov
National Institute of Standards & Technology
Manufacturing Systems Integration Division
100 Bureau Drive, Stop 8263                Tel: +1 301-975-3528
Gaithersburg, MD 20899-8263                Cel: +1 240-672-5800

"The opinions expressed above do not reflect consensus of NIST, 
and have not been reviewed by any Government authority."

[attachment "DTV Issue 16951-time point subdivision-d5.doc" deleted by Mark H Linehan/Watson/IBM] 



Content-Type: application/msword; name="Date-Time Issue 16951- time point"
 subdivision is out of place twice - d6.doc"
Content-Disposition: inline;
        filename*0="Date-Time Issue 16951- time point subdivision is out of plac";
        filename*1="e twice - d6.doc"


 Date-Time Issue 16951- time point.doc <Down>
<Down>
	Disposition: Resolved
	OMG Issue No:  16951 
Title:	Time point subdivision is out of place twice
Source: Ed Barkmeyer, NIST, edbark@nist.gov

Summary:
At the end of section 9.3 the fact type 'finite time scale subdivides time point' is defined and depicted in Figure 9-6.  This fact type is a commonly used property of finite time scales, and is not specific to individual time points.  That is, the finite time scale day-of-hours subdivides every day-of-month, for example.  So the text and diagram should be at the end of 9.2, where finite time scale is defined. 
Also, diagram 9-6 does not show the operations on time point and finite time scale that are associated with this fact type and shown in diagram 12-12.
Finally, diagram 12-12 (section 12.4) shows this fact type as well, but section 12.4 never uses it, and diagram 12-12 shows a <<specialization>> relationship that is never discussed anywhere in the text.  If the relationship is important, it should be discussed.  Otherwise, the subdivision association is out of place in diagram 12-12 and the "specialization" dependency should be deleted from the UML model.
Recommendation: Move the diagram and text for 'finite time scale subdivides time point' to the end of 9.2, include the operations on the diagram.  Delete the fact type from diagram 12-12, and delete the "specialization" dependency altogether.
Resolution:
The FTF agrees that the fact-type 'finite time scale subdivides time point' should be moved, along with Figure 9-6, but it depends on concepts defined in 9.3 and 9.4. It is an important concept that should have its own subsection.
The definition in 9.3 is inaccurate.  What is meant is that the corresponding time intervals are subdivided into intervals that the relative time points of the finite time scale correspond to.  
The concept should not appear in diagram 12-12. The "specialization" dependency should be deleted entirely. The intent is that this is a special case of 'time point converts to time point sequence on time scale', and that should be mentioned in a Note.
Revised Text:
1.  At the end of 9.3, DELETE the Figure 9.6 and the following text:
(Figure 9.6)
Figure 9.6: Time Scale Subdivision
finite time scale subdivides time point
Definition:	the finite time scale divides the time point into a number of time intervals that each have a duration, and the number is the cardinality of the finite time scale, and the duration is the granularity of the finite time scale
Example:	The day of hours scale subdivides the Gregorian date 3 January 2010 into 24 time intervals, each of duration "hour"

2.  Immediately before section 9.5, create a new subsection numbered 9.5, and renumber the subsequent sections: 
9.5 Time Point Subdivision
The purpose of finite time scales is to provide finer-grained resolution of time intervals within the time intervals that are instances of time points with coarser granularities.  In this specification the relationship between a finite time scale and a coarser time point is called .time point subdivision..  Many finite time scales are defined by the category of time point they subdivide and the granularity of the time points they contain.
 
Figure 9.x: Time Scale Subdivision
finite time scale subdivides time point1 into number of time point2*
Definition:	the finite time scale divides time point1 into a regular sequence of time point2 that is a subsequence of the finite time scale, that includes the index origin member of the finite time scale, that has number as its cardinality, and that implicitly divides each time interval that time point1 corresponds to into a sequence of consecutive time intervals, where each time point2 of the regular sequence corresponds to exactly one of the time intervals 
Necessity:	If a finite time scale subdivides a time point1 into some number of time point2, each time point on the finite time scale is an instance of time point2.
Note:	The asterisk after time point2 indicates that the role is an .intensional role. (per SBVR Annex C.1.6), that is, the role is played by a kind of time point, rather than by an instance of time point. 
Necessity:	If a finite time scale subdivides a time point1 into some number of time point2, there is a time point sequence such that 
  the time point sequence is on the finite time scale, and
  the first time point of the time point sequence is the index origin member of the finite time scale, and
  the cardinality of the time point sequence is the number, and
  the time point sequence corresponds to each time interval that is an instance of time point1.  
Note:	The definition says that the subdivision of time point1 is a regular sequence of time points on the finite time scale.  The Necessity above says that that regular sequence forms a time point sequence that corresponds to the same time intervals that time point1 does.  The principal concept of the subdivision, however, is that the individual members of the regular sequence . the time points on the finite time scale . correspond to sub-intervals of those time intervals.
Example:	The day of hours scale subdivides Gregorian date 3 January 2010 into 24 hour of day time points, and implicitly divides the time interval corresponding to Gregorian date 3 January 2010 into 24 time intervals, each of which is an instance of one hour-of-day.
Note:	A regular sequence of time points on a finite time scale makes up a time point sequence (see 9.3).   So, finite time scale subdivides time point superficially resembles time point converts to time point sequence on time scale (see 12.4).  The difference is this: finite time scale subdivides time point uses the time point and the finite time scale to define smaller time intervals with relative time coordinates (see 12.1.1).  time point converts to time point sequence on time scale relates the time point to a subsequence of a time scale that covers a longer span of time. 

[Editorial Note: Diagram 12-12 is modified by other issues.] 

Disposition:	Resolved

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Ed, 

Regarding 'regular sequence' versus 'sequence of consecutive': according to Annex D, a regular sequence is a consecutive sequence that is also a unique sequence.  Is your concern that the sequence of time intervals is not unique? 

Regarding the first Necessity: I think that the text "If a finite time scale subdivides a time point1 into some number of time point2," is not needed at all.  The Necessity applies to each instance of the verb concept.  SBVR practice clearly does not involve repeating the verb concept in the Necessity. 

Regarding the second Necessity: isn't the "regular sequence of time point2" in the Definition the same thing as the "time point sequence' of the Necessity?  If you combine the Necessity into the Definition, then (a) you avoid repeating much of the Definition in the Necessity; (b) we don't need "such that".  If we must have this second Necessity, then you can simply use "and", as in " there is a time point sequence and the time point sequence is on the finite time scale, and ... " 

I repeat from my previous email: What about updating the definitions of the 'Gregorian year of days scale' and the 'Gregorian month of days scale'? 
--------------------------------
Mark H. Linehan
STSM, IBM Research 



From:        Ed Barkmeyer <edbark@nist.gov> 
To:        Mark H Linehan/Watson/IBM@IBMUS, 
Cc:        "date-time-ftf@omg.org" <date-time-ftf@omg.org> 
Date:        08/02/2012 01:46 PM 
Subject:        Re: DTV Issue 16951 - Time point subdivision 

--------------------------------------------------------------------------------



I modified Mark's markup in one substantive way.  See the comment about "consecutive time intervals".
I don't object to deleting the Necessity about the time point sequence equivalent, but it is not the Definition -- it is formal, and the definition does not say anything about time point sequences (which is what converts to is about).

More importantly, I am still uncomfortable using the 'intensional role' in the verb concept wording.

The rest is just editorial disagreement.  

I understand that business people don't say 'such that', but they say things like "where" or "with the following properties", and SBVR Annex C does not include those expressions, either.  I would be happy with "where", but business people also use "where" to talk about locations, and Annex C suggests that that might also be valid SBVR SE.  The question is:  How does one phrase 'the following statements about the things in these roles are true", when the subjects of the verbs in those statements are different?  The 'such that' appears in a Necessity that states the existence of a time point sequence with 4 characteristics that involve different properties of it.

-Ed


-- 
Edward J. Barkmeyer                        Email: edbark@nist.gov
National Institute of Standards & Technology
Manufacturing Systems Integration Division
100 Bureau Drive, Stop 8263                Tel: +1 301-975-3528
Gaithersburg, MD 20899-8263                Cel: +1 240-672-5800

"The opinions expressed above do not reflect consensus of NIST, 
and have not been reviewed by any Government authority." 


Mark H Linehan wrote: 
The design looks fine to me.  I tried to simplify the wording in this version: 

The use of an intentional role looks right to me. 

What about updating the definitions of the 'Gregorian year of days scale' and the 'Gregorian month of days scale'? 
--------------------------------
Mark H. Linehan
STSM, IBM Research 



From:        Ed Barkmeyer <edbark@nist.gov> 
To:        OMG DateTimeVoc FTF <date-time-ftf@omg.org>, 
Date:        07/30/2012 06:29 PM 
Subject:        DTV Issue 16951 - Time point subdivision 

--------------------------------------------------------------------------------



One step forward and two steps back.  I attach yet another revision.
This one uses Mark's proposed rework of the verb concept wording, and it 
opens a new can of worms -- intensional roles.  So we need to decide 
about this wording.

I think we are agreed on the issue of the relationship to 'time point 
sequence' and to 'time point converts to time point sequence'.  The 
writeup may still need editing.

The problem with subdivision from day 1 is that we have all understood 
the intent, but formalizing it is tricky.

-Ed

-- 
Edward J. Barkmeyer                        Email: edbark@nist.gov
National Institute of Standards & Technology
Manufacturing Systems Integration Division
100 Bureau Drive, Stop 8263                Tel: +1 301-975-3528
Gaithersburg, MD 20899-8263                Cel: +1 240-672-5800

"The opinions expressed above do not reflect consensus of NIST, 
and have not been reviewed by any Government authority."

[attachment "DTV Issue 16951-time point subdivision-d5.doc" deleted by Mark H Linehan/Watson/IBM] 
[attachment "Date-Time Issue 16951- time point subdivision is out of place twice - d6.doc" deleted by Mark H Linehan/Watson/IBM] 
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Organization: NIST
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To: Mark H Linehan <mlinehan@us.ibm.com>
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Mark H Linehan wrote:
Ed,


Regarding 'regular sequence' versus 'sequence of consecutive': according to Annex D, a regular sequence is a consecutive sequence that is also a unique sequence.  Is your concern that the sequence of time intervals is not unique?


No.  I probably should have written a "sequence of contiguous time intervals".  It is a sequence of time intervals such that the time interval with index n /meets/ the time interval with index n+1.  Of course that sequence is 'regular', but the 'regularity' follows from the characterization, which itself follows from the definitions of the time points on the finite time scale. 
Using the term 'regular sequence' here is not sufficient to convey the 'contiguous intervals' meaning, and adds nothing to that meaning.  The sequence of time intervals is an intrinsically ordered set, and the time points give them indices. 
Regarding the first Necessity: I think that the text "If a _finite time scale_ /subdivides/ a _time point__1 /into/ some _number_ /of/ _time point__2 ," is not needed at all.  The Necessity applies to each instance of the verb concept.  SBVR practice clearly does not involve repeating the verb concept in the Necessity.


I do not believe that is true.  I got all the way thru SBVR v1.1 clause 8 without finding any example that supports Mark's thesis, and I found this counterexample on p.31:
Necessity:  If a designation is demonstrated by a verb concept wording of a verb concept, then the verb concept has the designation.
SBVR is logical:  If you mean: if P then Q, it does not suffice to say Q.


The trick here is that SBVR uses noun concept signifiers as placeholders (role signifiers) in most verb concept wordings, but in the Necessities in the entries, the noun concept signifier is quantified -- it refers to the noun concept, not the role.


Regarding the second Necessity: isn't the "regular sequence of time point2" in the Definition the same thing as the "time point sequence' of the Necessity? 


I see.  You are right that the definition of time point sequence says exactly that.  But 9.3 says a time point sequence does not correspond to a sequence of time intervals;  it corresponds to the hull of such a sequence.  The whole idea of subdivision is that the subsequence of the finite time scale corresponds to a sequence of time intervals that is the decomposition of the time interval that time point1 corresponds to.  
The time point sequence corresponds to the interval that instantiates time point1. 
The original wording said the sequence of time point2 was a time point sequence, which made the definition easier.  It also had the problem of making subdivides by definition a special case of converts to!  I was persuaded by Mark's previous email that the two concepts are different in what they correspond to, as the Note at the end tries to say.


If you combine the Necessity into the Definition, then (a) you avoid repeating much of the Definition in the Necessity; (b) we don't need "such that".  If we must have this second Necessity, then you can simply use "and", as in " there is a _time point sequence_ and the _time point sequence_ /is on/ the _finite time scale_, and ... "


Yes.  That is what I changed, in order to remove the statement that 'FTS subdivides TP' specializes 'TP converts to a subsequence of TS'.  I have no objection to putting both back, but if we are going to define subdivides to be a specialization, then let us please say that.  The problem here is that, as a state rather than an event, aggregation and decomposition are two views of the same relationship.


I repeat from my previous email: What about updating the definitions of the 'Gregorian year of days scale' and the 'Gregorian month of days scale'?


Oops!  OK.  I will add that.


-Ed



--------------------------------
Mark H. Linehan
STSM, IBM Research




From:        Ed Barkmeyer <edbark@nist.gov>
To:        Mark H Linehan/Watson/IBM@IBMUS,
Cc:        "date-time-ftf@omg.org" <date-time-ftf@omg.org>
Date:        08/02/2012 01:46 PM
Subject:        Re: DTV Issue 16951 - Time point subdivision
------------------------------------------------------------------------




I modified Mark's markup in one substantive way.  See the comment about "consecutive time intervals".
I don't object to deleting the Necessity about the time point sequence equivalent, but it is not the Definition -- it is formal, and the definition does not say anything about time point sequences (which is what converts to is about).


More importantly, I am still uncomfortable using the 'intensional role' in the verb concept wording.


The rest is just editorial disagreement.  


I understand that business people don't say 'such that', but they say things like "where" or "with the following properties", and SBVR Annex C does not include those expressions, either.  I would be happy with "where", but business people also use "where" to talk about locations, and Annex C suggests that that might also be valid SBVR SE.  The question is:  How does one phrase 'the following statements about the things in these roles are true", when the subjects of the verbs in those statements are different?  The 'such that' appears in a Necessity that states the existence of a time point sequence with 4 characteristics that involve different properties of it.


-Ed



-- 
Edward J. Barkmeyer                        Email: _edbark@nist.gov_ <mailto:edbark@nist.gov>
National Institute of Standards & Technology
Manufacturing Systems Integration Division
100 Bureau Drive, Stop 8263                Tel: +1 301-975-3528
Gaithersburg, MD 20899-8263                Cel: +1 240-672-5800


"The opinions expressed above do not reflect consensus of NIST,
and have not been reviewed by any Government authority."



Mark H Linehan wrote:
The design looks fine to me.  I tried to simplify the wording in this version:


The use of an intentional role looks right to me.


What about updating the definitions of the 'Gregorian year of days scale' and the 'Gregorian month of days scale'?
--------------------------------
Mark H. Linehan
STSM, IBM Research




From:        Ed Barkmeyer _<edbark@nist.gov>_ <mailto:edbark@nist.gov>
To:        OMG DateTimeVoc FTF _<date-time-ftf@omg.org>_ <mailto:date-time-ftf@omg.org>,
Date:        07/30/2012 06:29 PM
Subject:        DTV Issue 16951 - Time point subdivision
------------------------------------------------------------------------




One step forward and two steps back.  I attach yet another revision.
This one uses Mark's proposed rework of the verb concept wording, and it
opens a new can of worms -- intensional roles.  So we need to decide
about this wording.


I think we are agreed on the issue of the relationship to 'time point
sequence' and to 'time point converts to time point sequence'.  The
writeup may still need editing.


The problem with subdivision from day 1 is that we have all understood
the intent, but formalizing it is tricky.


-Ed


-- 
Edward J. Barkmeyer                        Email: _edbark@nist.gov_ <mailto:edbark@nist.gov>
National Institute of Standards & Technology
Manufacturing Systems Integration Division
100 Bureau Drive, Stop 8263                Tel: +1 301-975-3528
Gaithersburg, MD 20899-8263                Cel: +1 240-672-5800


"The opinions expressed above do not reflect consensus of NIST,
and have not been reviewed by any Government authority."


[attachment "DTV Issue 16951-time point subdivision-d5.doc" deleted by Mark H Linehan/Watson/IBM]
[attachment "Date-Time Issue 16951- time point subdivision is out of place twice - d6.doc" deleted by Mark H Linehan/Watson/IBM]


-- 
Edward J. Barkmeyer                        Email: edbark@nist.gov
National Institute of Standards & Technology
Manufacturing Systems Integration Division
100 Bureau Drive, Stop 8263                Tel: +1 301-975-3528
Gaithersburg, MD 20899-8263                Cel: +1 240-672-5800


"The opinions expressed above do not reflect consensus of NIST, and have not been reviewed by any Government authority."<Down>
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Date: Fri, 3 Aug 2012 18:30:25 -0400
From: Ed Barkmeyer <edbark@nist.gov>
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Yet another draft.  I added the Gregorian calendar stuff and repaired two other inconsistencies.  I summarized the open issues in the comments.


I would like to go back to defining subdivides as converting to a time point sequence, but I really think we then need to talk about the relationship of the time point sequence to a sequence of time intervals, rather than to one big one.  The original intent of time point sequence was to describe time periods of 3 hours or "1 June to 15 July".  That is not what subdivision is about, and upon reflection, I don't think that is what 'time point converts to time point sequence' is about, either.  
Subdivision is about a sequence of smaller time intervals.  And conversion is about reducing big time intervals to sequences of smaller ones so that you can resolve mixed arithmetic.


(Maybe the term 'time point sequence' for the time period concepts is a confusing choice.  We invented 'time point sequence' when we discovered we were using 'time period' to refer to the time point sequence and to the corresponding time intervals.)


-Ed




Ed Barkmeyer wrote:
Mark H Linehan wrote:
  
Ed,


Regarding 'regular sequence' versus 'sequence of consecutive': according to Annex D, a regular sequence is a consecutive sequence that is also a unique sequence.  Is your concern that the sequence of time intervals is not unique?
    


No.  I probably should have written a "sequence of contiguous time intervals".  It is a sequence of time intervals such that the time interval with index n /meets/ the time interval with index n+1.  Of course that sequence is 'regular', but the 'regularity' follows from the characterization, which itself follows from the definitions of the time points on the finite time scale. 
Using the term 'regular sequence' here is not sufficient to convey the 'contiguous intervals' meaning, and adds nothing to that meaning.  The sequence of time intervals is an intrinsically ordered set, and the time points give them indices. 
  
Regarding the first Necessity: I think that the text "If a _finite time scale_ /subdivides/ a _time point__1 /into/ some _number_ /of/ _time point__2 ," is not needed at all.  The Necessity applies to each instance of the verb concept.  SBVR practice clearly does not involve repeating the verb concept in the Necessity.
    


I do not believe that is true.  I got all the way thru SBVR v1.1 clause 8 without finding any example that supports Mark's thesis, and I found this counterexample on p.31:
Necessity:  If a designation is demonstrated by a verb concept wording of a verb concept, then the verb concept has the designation.
SBVR is logical:  If you mean: if P then Q, it does not suffice to say Q.


The trick here is that SBVR uses noun concept signifiers as placeholders (role signifiers) in most verb concept wordings, but in the Necessities in the entries, the noun concept signifier is quantified -- it refers to the noun concept, not the role.


  
Regarding the second Necessity: isn't the "regular sequence of time point2" in the Definition the same thing as the "time point sequence' of the Necessity?     


I see.  You are right that the definition of time point sequence says exactly that.  But 9.3 says a time point sequence does not correspond to a sequence of time intervals;  it corresponds to the hull of such a sequence.  The whole idea of subdivision is that the subsequence of the finite time scale corresponds to a sequence of time intervals that is the decomposition of the time interval that time point1 corresponds to.  
The time point sequence corresponds to the interval that instantiates time point1. 
The original wording said the sequence of time point2 was a time point sequence, which made the definition easier.  It also had the problem of making subdivides by definition a special case of converts to!  I was persuaded by Mark's previous email that the two concepts are different in what they correspond to, as the Note at the end tries to say.


  
If you combine the Necessity into the Definition, then (a) you avoid repeating much of the Definition in the Necessity; (b) we don't need "such that".  If we must have this second Necessity, then you can simply use "and", as in " there is a _time point sequence_ and the _time point sequence_ /is on/ the _finite time scale_, and ... "
    


Yes.  That is what I changed, in order to remove the statement that 'FTS subdivides TP' specializes 'TP converts to a subsequence of TS'.  I have no objection to putting both back, but if we are going to define subdivides to be a specialization, then let us please say that.  The problem here is that, as a state rather than an event, aggregation and decomposition are two views of the same relationship.


  
I repeat from my previous email: What about updating the definitions of the 'Gregorian year of days scale' and the 'Gregorian month of days scale'?
    


Oops!  OK.  I will add that.


-Ed



  
--------------------------------
Mark H. Linehan
STSM, IBM Research




From:        Ed Barkmeyer <edbark@nist.gov>
To:        Mark H Linehan/Watson/IBM@IBMUS,
Cc:        "date-time-ftf@omg.org" <date-time-ftf@omg.org>
Date:        08/02/2012 01:46 PM
Subject:        Re: DTV Issue 16951 - Time point subdivision
------------------------------------------------------------------------




I modified Mark's markup in one substantive way.  See the comment about "consecutive time intervals".
I don't object to deleting the Necessity about the time point sequence equivalent, but it is not the Definition -- it is formal, and the definition does not say anything about time point sequences (which is what converts to is about).


More importantly, I am still uncomfortable using the 'intensional role' in the verb concept wording.


The rest is just editorial disagreement.  


I understand that business people don't say 'such that', but they say things like "where" or "with the following properties", and SBVR Annex C does not include those expressions, either.  I would be happy with "where", but business people also use "where" to talk about locations, and Annex C suggests that that might also be valid SBVR SE.  The question is:  How does one phrase 'the following statements about the things in these roles are true", when the subjects of the verbs in those statements are different?  The 'such that' appears in a Necessity that states the existence of a time point sequence with 4 characteristics that involve different properties of it.


-Ed



-- 
Edward J. Barkmeyer                        Email: _edbark@nist.gov_ <mailto:edbark@nist.gov>
National Institute of Standards & Technology
Manufacturing Systems Integration Division
100 Bureau Drive, Stop 8263                Tel: +1 301-975-3528
Gaithersburg, MD 20899-8263                Cel: +1 240-672-5800


"The opinions expressed above do not reflect consensus of NIST,
and have not been reviewed by any Government authority."



Mark H Linehan wrote:
The design looks fine to me.  I tried to simplify the wording in this version:


The use of an intentional role looks right to me.


What about updating the definitions of the 'Gregorian year of days scale' and the 'Gregorian month of days scale'?
--------------------------------
Mark H. Linehan
STSM, IBM Research




From:        Ed Barkmeyer _<edbark@nist.gov>_ <mailto:edbark@nist.gov>
To:        OMG DateTimeVoc FTF _<date-time-ftf@omg.org>_ <mailto:date-time-ftf@omg.org>,
Date:        07/30/2012 06:29 PM
Subject:        DTV Issue 16951 - Time point subdivision
------------------------------------------------------------------------




One step forward and two steps back.  I attach yet another revision.
This one uses Mark's proposed rework of the verb concept wording, and it
opens a new can of worms -- intensional roles.  So we need to decide
about this wording.


I think we are agreed on the issue of the relationship to 'time point
sequence' and to 'time point converts to time point sequence'.  The
writeup may still need editing.


The problem with subdivision from day 1 is that we have all understood
the intent, but formalizing it is tricky.


-Ed


-- 
Edward J. Barkmeyer                        Email: _edbark@nist.gov_ <mailto:edbark@nist.gov>
National Institute of Standards & Technology
Manufacturing Systems Integration Division
100 Bureau Drive, Stop 8263                Tel: +1 301-975-3528
Gaithersburg, MD 20899-8263                Cel: +1 240-672-5800


"The opinions expressed above do not reflect consensus of NIST,
and have not been reviewed by any Government authority."


[attachment "DTV Issue 16951-time point subdivision-d5.doc" deleted by Mark H Linehan/Watson/IBM]
[attachment "Date-Time Issue 16951- time point subdivision is out of place twice - d6.doc" deleted by Mark H Linehan/Watson/IBM]
    


  


-- 
Edward J. Barkmeyer                        Email: edbark@nist.gov
National Institute of Standards & Technology
Manufacturing Systems Integration Division
100 Bureau Drive, Stop 8263                Tel: +1 301-975-3528
Gaithersburg, MD 20899-8263                Cel: +1 240-672-5800


"The opinions expressed above do not reflect consensus of NIST, and have not been reviewed by any Government authority."





 DTV Issue 16951-time point subdivision-d7.doc <Down>
<Down>

<Down>
Disposition: Resolved
OMG Issue No:  16951
Title:	Time point subdivision is out of place twice
Source:  Ed Barkmeyer, NIST, edbark@nist.gov

Summary:
At the end of section 9.3 the fact type 'finite time scale subdivides time point' is defined and depicted in Figure 9-6.  This fact type is a commonly used property of finite time scales, and is not specific to individual time points.  That is, the finite time scale day-of-hours subdivides every day-of-month, for example.  So the text and diagram should be at the end of 9.2, where finite time scale is defined. 
Also, diagram 9-6 does not show the operations on time point and finite time scale that are associated with this fact type and shown in diagram 12-12.
Finally, diagram 12-12 (section 12.4) shows this fact type as well, but section 12.4 never uses it, and diagram 12-12 shows a <<specialization>> relationship that is never discussed anywhere in the text.  If the relationship is important, it should be discussed.  Otherwise, the subdivision association is out of place in diagram 12-12 and the "specialization" dependency should be deleted from the UML model.
Recommendation: Move the diagram and text for 'finite time scale subdivides time point' to the end of 9.2, include the operations on the diagram.  Delete the fact type from diagram 12-12, and delete the "specialization" dependency altogether.

Resolution:
The FTF agrees that the fact-type 'finite time scale subdivides time point' should be moved, along with Figure 9-6, but it depends on concepts defined in 9.3 and 9.4. It is an important concept that should have its own subsection.
The verb concept 'finite time scale subdivides time point'definition in 9.3 is inaccurate.  What is meant is that the corresponding time intervals are subdivided into intervals that the relative time points of the finite time scale correspond to.  
The concept should not appear in diagram 12-12. The "specialization" dependency should be deleted entirely.  (Diagram 12-12 is modified by other issues.) The intent is that this is a special case of 'time point converts to time point sequence on time scale', and that should be mentioned in a Note.

Revised Text:
1.  At the end of 9.3, DELETE the Figure 9.6 and the following text:
(Figure 9.6)
Figure 9.6: Time Scale Subdivision
finite time scale subdivides time point
Definition:	the finite time scale divides the time point into a number of time intervals that each have a duration, and the number is the cardinality of the finite time scale, and the duration is the granularity of the finite time scale
Example:	The day of hours scale subdivides the Gregorian date 3 January 2010 into 24 time intervals, each of duration "hour"

2.  Immediately before section 9.5, create a new subsection numbered 9.5, and renumber the subsequent sections: 
9.5 Time Point Subdivision
The purpose of finite time scales is to provide finer-grained resolution of time intervals within the time intervals that are instances of time points with coarser granularities.  In this specification the relationship between a finite time scale and a coarser time point is called .time point subdivision..  Many finite time scales are defined by the category of time point they subdivide and the granularity of the time points they contain.
 
Figure 9.x: Time Scale Subdivision 
finite time scale subdivides time point1  into number of time point2*
Definition:	the finite time scale divides time point1 into a regular sequence1 of time point2 that is a subsequence of the finite time scale, that includes the index origin member of the finite time scale, that has number as its cardinality, and that implicitly divides each time interval that time point1 corresponds to into a regular sequence2 of time intervals, where each time point2 of regular sequence1 corresponds to exactly one of the time intervals  
Necessity:	If a finite time scale subdivides a time point1 into some number of time point2, each time point on the finite time scale is an instance of time point2. 
Note:	The asterisk after time point2 indicates that the role is an .intensional role. (per SBVR Annex C.1.6), that is, the role is played by a kind of time point, rather than by an instance of time point. 
Necessity:	If a finite time scale subdivides a time point1 into some number of time point2, there is a time point sequence such that   
  the time point sequence is on the finite time scale, and
  the first time point of the time point sequence is the index origin member of the finite time scale, and
  the cardinality of the time point sequence is the number, and
  the time point sequence corresponds to each time interval that is an instance of time point1.  
Note:	The definition says that the subdivision of time point1 is a regular sequence of time points on the finite time scale.  The Necessity above says that that regular sequence forms a time point sequence that corresponds to the same time intervals that time point1 does.  The principal concept of the subdivision, however, is that the individual members of the regular sequence . the time points on the finite time scale . correspond to sub-intervals of those time intervals. 
Example:	The day of hours scale subdivides Gregorian date 3 January 2010 into 24 hour of day time points, and implicitly divides the time interval corresponding to Gregorian date 3 January 2010 into 24 time intervals, each of which is an instance of one hour-of-day.
Note:	A regular sequence of time points on a finite time scale makes up a time point sequence (see 9.3).   So, finite time scale subdivides time point superficially resembles time point converts to time point sequence on time scale (see 12.4).  The difference is this: finite time scale subdivides time point uses the time point and the finite time scale to define smaller time intervals with relative time coordinates (see 12.1.1).  time point converts to time point sequence on time scale relates the time point to a subsequence of a time scale that covers a longer span of time.  

[Editorial Note: Diagram 12-12 is modified by other issues.] 

3.  In clause 9.5.5, in the entry for 'Gregorian year of days scale', REPLACE the Definition paragraph:
Definition:	the finite time scale that subdivides .Gregorian year. into 366 of .Gregorian day of year.
with:
Definition:	the finite time scale that subdivides each leap year into 366 of .Gregorian day of year. and that subdivides each common year into 365 of .Gregorian day of year.
4.  In clause 9.5.5, in the entry for 'Gregorian month of days scale', REPLACE the Definition paragraph:
Definition:	the finite time scale that subdivides .Gregorian month. into 31 of .Gregorian day of month.
with:
Definition:	the finite time scale that subdivides each 'Gregorian month' into at most 31 of .Gregorian day of month. 
Note:	Each Gregorian month is subdivided into a specific subsequence of Gregorian day of month time points.

Disposition:	Resolved

Date: Tue, 7 Aug 2012 19:25:10 -0400
From: Ed Barkmeyer <edbark@nist.gov>
Reply-To: <edbark@nist.gov>
Organization: NIST
User-Agent: Thunderbird 2.0.0.23 (Windows/20090812)
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Subject: Issue 16951 - time scale subdivides time point -- the confusion continues
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At the last telecon we agreed that time scale subdivides time point may indeed be a specialization of time point converts to time point sequence on time scale.


It appears that that is not true.  In clause 10.8 (beta2), time point converts to time point sequence on time scale, we have
Definition: the time point is coextensive with the time point sequence
Possibility:  The time point is an absolute time point or is a relative time point.
The possibility is redundant:  every time point is either absolute or relative.
But, together with the Definition, this gives the following much stronger statement:
Necessity:  If the time point is an absolute time point, then the time scale is an indefinite time scale.
Necessity:  If the time point is a relative time point, then the time scale is a finite time scale.
These must be so because the time point and the time point sequence are coextensive. 
OTOH, we very much intend that finite time scale subdivides time point can relate a finite time scale to an absolute time point.  We want to allow the year-of-months to subdivide Gregorian year time points, like '2012'.  The time point sequence on the finite time scale need not be co-extensive with the time point; the time point sequence per se could have a much larger extension.  Subdivision is about selecting subintervals in the extension of the time point.  For subdivides, there is a time point sequence that begins with the origin of the finite time scale and that corresponds to every time interval in the extension of the time point (and possible more time intervals).  Within any such time interval, there is a sequence of time intervals, one for each time point in the time point sequence. 
Example: March refers to a large set of time intervals, and month-of-days subdivides March so that day-of-month 3 refers to exactly one 24-hour time interval within each March.  March 2012 corresponds to one time interval and month-of-days subdivides March 2012, so that day-of-month 3 refers to exactly one 24-hour time interval within the March 2012.  In both cases, the subintervals are characterized by being part of a March, having a duration of 1 day (the granularity of month-of-days), and by starting 2 days after the start of the March (the meaning of index 3).  The subdivision is the "being part of a March" characteristic; the rest follows from the definition of the time points. 
We only use the term 'subdivides' in defining time scales.  The finite time scale 'month-of-days' itself is characterized by having every time point defined in terms of its relationship to the start of a calendar month.  So, in one sense, that is all that is meant by 'month-of-days subdivides each calendar month'.  And the 'into 31 day-of-month' part is just a strange way of saying 'month-of-days' has 31 time points and granularity 'day'.  I really think that is all 'subdivides' means, and we should just define it accordingly.  Then March 'converts to' the time point sequence that is on 'month of days', that has 31 time points, and that begins with the origin (which is what we thought we meant by 'subdivides').


The remaining problem is that year 2012 does not 'convert to' a time point sequence on year-of-months, and '1 June 2010' does not 'convert to' a time point sequence on 'day of hours'.  The extensions are different.


So, where do we go from here?


-Ed



-- 
Edward J. Barkmeyer                        Email: edbark@nist.gov
National Institute of Standards & Technology
Manufacturing Systems Integration Division
100 Bureau Drive, Stop 8263                Tel: +1 301-975-3528
Gaithersburg, MD 20899-8263                Cel: +1 240-672-5800


"The opinions expressed above do not reflect consensus of NIST, and have not been reviewed by any Government authority."<Down>
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Subject: Re: Issue 16951 - time scale subdivides time point -- the confusion
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My comments like this. 
--------------------------------
Mark H. Linehan
STSM, IBM Research 



From:        Ed Barkmeyer <edbark@nist.gov> 
To:        OMG DateTimeVoc FTF <date-time-ftf@omg.org>, 
Date:        08/07/2012 07:27 PM 
Subject:        Issue 16951 - time scale subdivides time point -- the confusion continues 

--------------------------------------------------------------------------------



At the last telecon we agreed that time scale subdivides time point may 
indeed be a specialization of time point converts to time point sequence 
on time scale. 
Hmm, I thought we said that 'subdivides' may use 'converts' in its definition, not that 'subdivides' is a specialization of 'converts'. 
Where that is true or not remains to be determined.

It appears that that is not true.  In clause 10.8 (beta2), time point 
converts to time point sequence on time scale, we have
Definition: the time point is coextensive with the time point sequence
Possibility:  The time point is an absolute time point or is a relative 
time point.
The possibility is redundant:  every time point is either absolute or 
relative. 
Yes.  I think the point of the Possibility statement is to emphasize that this verb concept applies to both kinds of time points.
But, together with the Definition, this gives the following much 
stronger statement:
Necessity:  If the time point is an absolute time point, then the time 
scale is an indefinite time scale.
Necessity:  If the time point is a relative time point, then the time 
scale is a finite time scale.
These must be so because the time point and the time point sequence are 
coextensive. 
Yes.

OTOH, we very much intend that finite time scale subdivides time point 
can relate a finite time scale to an absolute time point.  We want to 
allow the year-of-months to subdivide Gregorian year time points, like 
'2012'.  The time point sequence on the finite time scale need not be 
co-extensive with the time point; the time point sequence per se could 
have a much larger extension.  Subdivision is about selecting 
subintervals in the extension of the time point.  For subdivides, there 
is a time point sequence that begins with the origin of the finite time 
scale and that corresponds to every time interval in the extension of 
the time point (and possible more time intervals).  Within any such time 
interval, there is a sequence of time intervals, one for each time point 
in the time point sequence. 
Yes.

Example: March refers to a large set of time intervals, and 
month-of-days subdivides March so that day-of-month 3 refers to exactly 
one 24-hour time interval within each March.  March 2012 corresponds to 
one time interval and month-of-days subdivides March 2012, so that 
day-of-month 3 refers to exactly one 24-hour time interval within the 
March 2012.  In both cases, the subintervals are characterized by being 
part of a March, having a duration of 1 day (the granularity of 
month-of-days), and by starting 2 days after the start of the March (the 
meaning of index 3).  The subdivision is the "being part of a March" 
characteristic; the rest follows from the definition of the time points. 
Yes. 

We only use the term 'subdivides' in defining time scales.  The finite 
time scale 'month-of-days' itself is characterized by having every time 
point defined in terms of its relationship to the start of a calendar 
month.  So, in one sense, that is all that is meant by 'month-of-days 
subdivides each calendar month'.  And the 'into 31 day-of-month' part is 
just a strange way of saying 'month-of-days' has 31 time points and 
granularity 'day'.  I really think that is all 'subdivides' means, and 
we should just define it accordingly.  Then March 'converts to' the time 
point sequence that is on 'month of days', that has 31 time points, and 
that begins with the origin (which is what we thought we meant by 
'subdivides'). 
Yes, what's wrong with that?

The remaining problem is that year 2012 does not 'convert to' a time 
point sequence on year-of-months, and '1 June 2010' does not 'convert 
to' a time point sequence on 'day of hours'.  The extensions are different. 
I agree.  So clearly 'subdivides' is not a specialization of 'converts'.  I thought we had already agreed that. 
You've just explained why very clearly.

So, where do we go from here? 
As you said, we should define 'subdivides' appropriately. 

Here's an idea that I propose should be part of the definition of 'finite time scale subdivides time point1 into number of time point2': 
the first member of the finite time scale starts each time interval that time point1 corresponds to, and 
the last member of the finite time scale ends each time interval that time point1 corresponds to. (This relies on several verb 
concepts from beta 8.5.) 

Add to that the idea that the cardinality of the finite time scale is the number and the granularity of the finite time 
scale is the duration of time point2.

-Ed


-- 
Edward J. Barkmeyer                        Email: edbark@nist.gov
National Institute of Standards & Technology
Manufacturing Systems Integration Division
100 Bureau Drive, Stop 8263                Tel: +1 301-975-3528
Gaithersburg, MD 20899-8263                Cel: +1 240-672-5800

"The opinions expressed above do not reflect consensus of NIST, 
and have not been reviewed by any Government authority."


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Subject: Re: Issue 16951 - time scale subdivides time point -- the confusion
 continues
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This is a retry at Issue 16951.  It is much simpler than what we were trying to do before.
There are still some questions in the margin.


Is this better.


-Ed



Ed Barkmeyer wrote:
At the last telecon we agreed that time scale subdivides time point may indeed be a specialization of time point converts to time point sequence on time scale.


It appears that that is not true.  In clause 10.8 (beta2), time point converts to time point sequence on time scale, we have
Definition: the time point is coextensive with the time point sequence
Possibility:  The time point is an absolute time point or is a relative time point.
The possibility is redundant:  every time point is either absolute or relative.
But, together with the Definition, this gives the following much stronger statement:
 Necessity:  If the time point is an absolute time point, then the time scale is an indefinite time scale.
 Necessity:  If the time point is a relative time point, then the time scale is a finite time scale.
These must be so because the time point and the time point sequence are coextensive. 
OTOH, we very much intend that finite time scale subdivides time point can relate a finite time scale to an absolute time point.  We want to allow the year-of-months to subdivide Gregorian year time points, like '2012'.  The time point sequence on the finite time scale need not be co-extensive with the time point; the time point sequence per se could have a much larger extension.  Subdivision is about selecting subintervals in the extension of the time point.  For subdivides, there is a time point sequence that begins with the origin of the finite time scale and that corresponds to every time interval in the extension of the time point (and possible more time intervals).  Within any such time interval, there is a sequence of time intervals, one for each time point in the time point sequence. 
Example: March refers to a large set of time intervals, and month-of-days subdivides March so that day-of-month 3 refers to exactly one 24-hour time interval within each March.  March 2012 corresponds to one time interval and month-of-days subdivides March 2012, so that day-of-month 3 refers to exactly one 24-hour time interval within the March 2012.  In both cases, the subintervals are characterized by being part of a March, having a duration of 1 day (the granularity of month-of-days), and by starting 2 days after the start of the March (the meaning of index 3).  The subdivision is the "being part of a March" characteristic; the rest follows from the definition of the time points. 
We only use the term 'subdivides' in defining time scales.  The finite time scale 'month-of-days' itself is characterized by having every time point defined in terms of its relationship to the start of a calendar month.  So, in one sense, that is all that is meant by 'month-of-days subdivides each calendar month'.  And the 'into 31 day-of-month' part is just a strange way of saying 'month-of-days' has 31 time points and granularity 'day'.  I really think that is all 'subdivides' means, and we should just define it accordingly.  Then March 'converts to' the time point sequence that is on 'month of days', that has 31 time points, and that begins with the origin (which is what we thought we meant by 'subdivides').


The remaining problem is that year 2012 does not 'convert to' a time point sequence on year-of-months, and '1 June 2010' does not 'convert to' a time point sequence on 'day of hours'.  The extensions are different.


So, where do we go from here?


-Ed



  


-- 
Edward J. Barkmeyer                        Email: edbark@nist.gov
National Institute of Standards & Technology
Manufacturing Systems Integration Division
100 Bureau Drive, Stop 8263                Tel: +1 301-975-3528
Gaithersburg, MD 20899-8263                Cel: +1 240-672-5800


"The opinions expressed above do not reflect consensus of NIST, and have not been reviewed by any Government authority."





 DTV Issue 16951-time point subdivision-d8.docx <Down>
Disposition: Resolved
OMG Issue No:  16951
Title:	Time point subdivision is out of place twice
Source:  Ed Barkmeyer, NIST, edbark@nist.gov

Summary:
At the end of section 9.3 the fact type 'finite time scale subdivides time point' is defined and depicted in Figure 9-6.  This fact type is a commonly used property of finite time scales, and is not specific to individual time points.  That is, the finite time scale day-of-hours subdivides every day-of-month, for example.  So the text and diagram should be at the end of 9.2, where finite time scale is defined. 
Also, diagram 9-6 does not show the operations on time point and finite time scale that are associated with this fact type and shown in diagram 12-12.
Finally, diagram 12-12 (section 12.4) shows this fact type as well, but section 12.4 never uses it, and diagram 12-12 shows a <<specialization>> relationship that is never discussed anywhere in the text.  If the relationship is important, it should be discussed.  Otherwise, the subdivision association is out of place in diagram 12-12 and the "specialization" dependency should be deleted from the UML model.
Recommendation: Move the diagram and text for 'finite time scale subdivides time point' to the end of 9.2, include the operations on the diagram.  Delete the fact type from diagram 12-12, and delete the "specialization" dependency altogether.

Resolution:
The FTF agrees that the fact-type 'finite time scale subdivides time point' should be moved, along with Figure 9-6, but it depends on concepts defined in 9.3 and 9.4. It is an important concept that should have its own subsection.  This concept is used only in defining finite time scales within Calendars.  So the new section goes in clause 10 (formerly 9.5) Calendars.  
The verb concept 'finite time scale subdivides time point' is not quite the way it is used.  All of the existing usages have the form:  'finite time scale subdivides time point into number of time point kind.'  But the finite time scale determines the time point kind, so that is redundant.  Also, it is not clear whether the intent is to specify the cardinality of the finite time scale or the cardinality of the time point sequence that is the subdivision of individual time points, such as months of the year.  The text is revised to clarify that.  
The concept in diagram 10.14 (formerly 12.12) . time point converts to time point sequence on time scale . is only distantly related.  The nature of the time point sequences involved is different, and the purposes are different.  The purpose of time point subdivision is to be part of the definition of finite time scales.  Diagram 10.14 (formerly 12.12) no longer shows the "specialization"; it was removed by resolution of another issue.  

Revised Text:
1.  At the end of 8.5 (was 9.3), DELETE Figure 8.18 (was 9.6) and the following text:
(Figure 8.18)
Figure 8.18: Time Scale Subdivision
finite time scale subdivides time point
Definition:	the finite time scale divides the time point into a number of time intervals that each have a duration, and the number is the cardinality of the finite time scale, and the duration is the granularity of the finite time scale
Example:	The day of hours scale subdivides the Gregorian date 3 January 2010 into 24 time intervals, each of duration "hour"

2.  Immediately before section 10.3 (was 9.5), create a new subsection numbered 10.3, and renumber the subsequent sections: 
10.3  Time Point Subdivision
The purpose of finite time scales is to provide finer-grained resolution of time intervals within the time intervals that are instances of time points with coarser granularities.  In this specification the relationship between a finite time scale and a coarser time point is called .time point subdivision..  Many finite time scales are defined by the category of time point they subdivide and the granularity of the time points they contain.
 
Figure 10.x: Time Point Subdivision 
finite time scale subdivides time point  into number time points
Definition:	there is a time point sequence that is on the finite time scale, and
  the first time point of the time point sequence is the index origin member of the finite time scale, and
  the cardinality of the time point sequence is the number, and
  the time point sequence corresponds to each time interval that is an instance of time point
Note:	This verb concept describes the purpose of the finite time scale:  each time point of the finite time scale corresponds to time intervals according to their position relative to the start of a time interval that time point corresponds to.  The first time point of the finite time scale corresponds to time intervals that start the larger time intervals and have a duration equal to the granularity of the finite time scale.
Necessity:	If a finite time scale subdivides a time point into some number time points, the granularity of the finite time scale is less than the granularity of time point. 
Necessity:	If a finite time scale subdivides a time point1 into some number time points, the cardinality of the finite time scale is greater than or equal to number.  
Note:	The time point sequence corresponds to many more time intervals than the instances of the time point.  
Example:	The day of hours scale subdivides Gregorian day 3 January 2010 into 24 time points, and implicitly divides the time interval corresponding to Gregorian date 3 January 2010 into 24 time intervals, each of which is an instance of one hour-of-day.  But that same 24-hour time point sequence is the subdivision of every Gregorian day, and it corresponds to every Gregorian day time interval.

3.  In clause 11.1 (was 9.5.5), in the entry for 'Gregorian year of months scale', REPLACE the Definition and the first Necessity:
Definition:	the finite time scale that subdivides .Gregorian year. into 12 of .Gregorian month of year.
Necessity:	The granularity of the Gregorian year of months scale is .month..
with:
Definition:	the finite time scale that has granularity 1 month and that has cardinality 12 and that subdivides each Gregorian year into 12 time points .
4.  In clause 11.1 (was 9.5.5), in the entry for 'Gregorian year of days scale', REPLACE the Definition and the first Necessity:
Definition:	the finite time scale that subdivides .Gregorian year. into 366 of .Gregorian day of year.
Necessity:	The granularity of the Gregorian year of days scale is .day..
with:
Definition:	the finite time scale that has granularity 1 day and that has cardinality 366 and that subdivides each leap year into 366 time points  and that subdivides each common year into 365 time points
5.  In clause 11.1 (was 9.5.5), in the entry for 'Gregorian month of days scale', REPLACE the Definition and the first Necessity:
Definition:	the finite time scale that subdivides .Gregorian month. into 31 of .Gregorian day of month.
Necessity:	The granularity of the Gregorian month of days scale is .day..
with:
Definition:	the finite time scale that has granularity 1 day and that has cardinality 31 and that subdivides each 'Gregorian month' into at most 31 time points  
Note:	Each Gregorian month is subdivided into a specific subsequence of Gregorian day of month time points.

Disposition:	Resolved

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Subject: Re: Issue 16951 - time scale subdivides time point -- the confusion
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I guess our email about this issue crossed, but I'm not sure it matters. 

Regarding the 'subdivides' verb concept itself, I think we need to specify the kind of time point as a role of the verb concept.  Otherwise, we haven't specified the kind of time points that makeup the finite time scale.  And I think that the kind of time points is intrinsic to the subdivision "function". 

Regarding the definition: I don't think we have (but should have) 'time point sequence on time scale'.  Otherwise, I think the definition goes in the right direction. 

I still think we can drop "If a finite time scale subdivides a time point into some number time points, " from the start of the Necessities. 
  * We don't do this in other glossary entries.  For example, under 'time point1 through time point2 specifies time period', I see a Necessity "The time scale of time point1 is the time scale of time point2.". 
  * When we use "the" in a Necessity or Definition, the reference is to a role of the verb concept.  See SBVR Annex C.3.2.3. 

The Example has two formatting errors: (a) alignment of the first line; (b) "into" and "time points" should be in verb style. 

Regarding the definitions of 'Gregorian year of months scale' and similar: 
  * Putting just the granularity into the definition does not distinguish among different time points that have the same granularity.  For example, 'Gregorian day of month' and 'Gregorian day of year' have the same granularity. 
  * On the other hand, specifying the time point kind implies the granularity since each time point has a particular granularity. 
  * I think the number of time points in the finite time scale should be a role of the 'subdivides' verb concept because it is intrinsic to the "subdivides" function.  I can see that you agree with me in your comment about the definition of 'Gregorian year of days scale'. 
  * For 'Gregorian month of days scale', I thought we were going to specify the number of time points in each calendar month, month by month.  Although I guess that doesn't work for February. 
--------------------------------
Mark H. Linehan
STSM, IBM Research 



From:        Ed Barkmeyer <edbark@nist.gov> 
To:        "Barkmeyer, Edward J" <edward.barkmeyer@nist.gov>, 
Cc:        OMG DateTimeVoc FTF <date-time-ftf@omg.org> 
Date:        08/08/2012 07:04 PM 
Subject:        Re: Issue 16951 - time scale subdivides time point -- the confusion continues 

--------------------------------------------------------------------------------



This is a retry at Issue 16951.  It is much simpler than what we were 
trying to do before.
There are still some questions in the margin.

Is this better.

-Ed


Ed Barkmeyer wrote:
> At the last telecon we agreed that time scale subdivides time point may 
> indeed be a specialization of time point converts to time point sequence 
> on time scale.
>
> It appears that that is not true.  In clause 10.8 (beta2), time point 
> converts to time point sequence on time scale, we have
> Definition: the time point is coextensive with the time point sequence
> Possibility:  The time point is an absolute time point or is a relative 
> time point.
> The possibility is redundant:  every time point is either absolute or 
> relative.
> But, together with the Definition, this gives the following much 
> stronger statement:
>  Necessity:  If the time point is an absolute time point, then the time 
> scale is an indefinite time scale.
>  Necessity:  If the time point is a relative time point, then the time 
> scale is a finite time scale.
> These must be so because the time point and the time point sequence are 
> coextensive. 
>
> OTOH, we very much intend that finite time scale subdivides time point 
> can relate a finite time scale to an absolute time point.  We want to 
> allow the year-of-months to subdivide Gregorian year time points, like 
> '2012'.  The time point sequence on the finite time scale need not be 
> co-extensive with the time point; the time point sequence per se could 
> have a much larger extension.  Subdivision is about selecting 
> subintervals in the extension of the time point.  For subdivides, there 
> is a time point sequence that begins with the origin of the finite time 
> scale and that corresponds to every time interval in the extension of 
> the time point (and possible more time intervals).  Within any such time 
> interval, there is a sequence of time intervals, one for each time point 
> in the time point sequence. 
>
> Example: March refers to a large set of time intervals, and 
> month-of-days subdivides March so that day-of-month 3 refers to exactly 
> one 24-hour time interval within each March.  March 2012 corresponds to 
> one time interval and month-of-days subdivides March 2012, so that 
> day-of-month 3 refers to exactly one 24-hour time interval within the 
> March 2012.  In both cases, the subintervals are characterized by being 
> part of a March, having a duration of 1 day (the granularity of 
> month-of-days), and by starting 2 days after the start of the March (the 
> meaning of index 3).  The subdivision is the "being part of a March" 
> characteristic; the rest follows from the definition of the time points. 
>
> We only use the term 'subdivides' in defining time scales.  The finite 
> time scale 'month-of-days' itself is characterized by having every time 
> point defined in terms of its relationship to the start of a calendar 
> month.  So, in one sense, that is all that is meant by 'month-of-days 
> subdivides each calendar month'.  And the 'into 31 day-of-month' part is 
> just a strange way of saying 'month-of-days' has 31 time points and 
> granularity 'day'.  I really think that is all 'subdivides' means, and 
> we should just define it accordingly.  Then March 'converts to' the time 
> point sequence that is on 'month of days', that has 31 time points, and 
> that begins with the origin (which is what we thought we meant by 
> 'subdivides').
>
> The remaining problem is that year 2012 does not 'convert to' a time 
> point sequence on year-of-months, and '1 June 2010' does not 'convert 
> to' a time point sequence on 'day of hours'.  The extensions are different.
>
> So, where do we go from here?
>
> -Ed
>
>
>   

-- 
Edward J. Barkmeyer                        Email: edbark@nist.gov
National Institute of Standards & Technology
Manufacturing Systems Integration Division
100 Bureau Drive, Stop 8263                Tel: +1 301-975-3528
Gaithersburg, MD 20899-8263                Cel: +1 240-672-5800

"The opinions expressed above do not reflect consensus of NIST, 
and have not been reviewed by any Government authority."

[attachment "DTV Issue 16951-time point subdivision-d8.docx" deleted by Mark H Linehan/Watson/IBM] 
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Mark H Linehan wrote: 
I guess our email about this issue crossed, but I'm not sure it matters. 

Regarding the 'subdivides' verb concept itself, I think we need to specify the kind of time point as a role of the verb concept.  Otherwise, we haven't specified the kind of time points that makeup the finite time scale.  And I think that the kind of time points is intrinsic to the subdivision "function". 


Identifying the finite time scale specifies the kind of time point.  Each time point is on exactly one time scale, and each time scale has exactly one kind of time point.  The time point 'day of month', for example, is defined as:  time point on the month of days time scale.


Regarding the definition: I don't think we have (but should have) 'time point sequence on time scale'.  Otherwise, I think the definition goes in the right direction. 


Point taken.  We could define it as a subsequence of the time scale, but that notion is not defined in Annex D.



I still think we can drop "If a finite time scale subdivides a time point into some number time points, " from the start of the Necessities. 
  * We don't do this in other glossary entries.  For example, under 'time point1 through time point2 specifies time period', I see a Necessity "The time scale of time point1 is the time scale of time point2.". 


I think this is an indication that there are errors in the DTV specification.  I forwarded this argument to the SBVR lot.


  * When we use "the" in a Necessity or Definition, the reference is to a role of the verb concept.  See SBVR Annex C.3.2.3. 


Annex C.3.2.3 refers only to the use of placeholder terms within Definitions.  It says nothing about Necessities.  Part of the issue sent to SBVR RTF.


The Example has two formatting errors: (a) alignment of the first line; (b) "into" and "time points" should be in verb style. 


I don't see the alignment error in Word 2007, but it seems to be unable to edit the SBVR paragraph numbering structures that were supported by Word 200x where x < 7.  Instead we have the incompatible and untested 'multilevel list'.

Assuming we keep this, I will correct (b).


Regarding the definitions of 'Gregorian year of months scale' and similar: 
  * Putting just the granularity into the definition does not distinguish among different time points that have the same granularity.  For example, 'Gregorian day of month' and 'Gregorian day of year' have the same granularity.
  * On the other hand, specifying the time point kind implies the granularity since each time point has a particular granularity. 


This is a cart/horse problem.  The time points are defined in terms of the scale, and they get their granularity from it.  The scale is made unique by specifying its granularity and what it subdivides!  That is the whole point of 'subdivides'.  It is an essential property of each finite time scale, and one of its delimiting properties.

(A time scale is not an ad hoc sequence of existing time points that are its members.  The time points are structurally part of the scale; they depend on the scale for their existence, like sequence positions in Annex D.)


  * I think the number of time points in the finite time scale should be a role of the 'subdivides' verb concept because it is intrinsic to the "subdivides" function.  I can see that you agree with me in your comment about the definition of 'Gregorian year of days scale'. 


Well, as you can see in the three cases, they all use the 'number' differently.  So what is intrinsic?  The nature of 'year of months' is to subdivide  'Gregorian year' and it subdivides every Gregorian year into 12 time points.  The nature of 'year of days' is to subdivide 'Gregorian year', but it is stated (instead) to subdivide both common year and leap year and it subdivides them into different numbers of time points.  The nature of 'month of days' is to subdivide 'Gregorian month' but it is stated to have a variable 'number' of time points.  If it followed the year of days pattern, it would instead have 12 specific variants.  

So I don't think the number is intrinsic to 'subdivides' as a means of defining finite time scales.  The problem is to distinguish between subdividing by nature a class of time points, from doing something to a given time point.  There wouldn't be a distinction if subdivision did the same thing to every such time point.

I notice, however, that there is a problem with 'month of days'.  It seems to me that the 'month of days' time scale can subdivide either/both of 'Gregorian month' (an absolute time point) and 'Gregorian month of year' (a relative time point).  Those time points do not correspond to the same time intervals, but they are both subtypes of an unspecified concept 'Gregorian calendar month'.

So, I'm not sure what exactly the 'subdivides' idea is.  (I guess I only thought I understood this.)


  * For 'Gregorian month of days scale', I thought we were going to specify the number of time points in each calendar month, month by month.  Although I guess that doesn't work for February. 


OK.  That would almost eliminate the the third kind of subdivision above, but it doesn't generalize to 'G calendar month'.  It is not the nature of 'month of days' to subdivide February; it is the nature of 'month of days' to subdivide 'Gregorian calendar months' as a class, or equivalently any and all.  When 'month of days' is used to subdivide a given calendar month, that is when the n time points appears.

I think there are two ideas:
 - a finite time scale is characterized by subdividing1 a category of time points (and every time point in the category), full stop.  The definition of the time points in the scale is based on anchoring the scale on the start of the subdivided time point (suitably phrased).  If we eliminate the cardinality from the proposed definition, it seems to work.
 - a finite time scale subdivides2 a specific time point into a specific number of time points (a specific time point sequence).  subdivides2 looks like 'converts to', but the time point sequence per se does not have the same extension.  The intent is to define the component time periods.  And the time point sequence forms only part of the reference scheme for the component time intervals, they all also have to be part of the/a time interval that the subdivided time point corresponds to.

(The idea of 'converts to' is to turn the time point into a time point sequence that corresponds to exactly the same time intervals, so that you can operate on the time point sequence (in its time scale) to define related time intervals.  The idea of subdivides2 is to use the subdivided time point together with time points in the time point sequence to identify sub-intervals.  I suppose the idea of "using the time point sequence (somehow) to identify related time intervals" is common to both.)

-Ed


--------------------------------
Mark H. Linehan
STSM, IBM Research 



From:        Ed Barkmeyer <edbark@nist.gov> 
To:        "Barkmeyer, Edward J" <edward.barkmeyer@nist.gov>, 
Cc:        OMG DateTimeVoc FTF <date-time-ftf@omg.org> 
Date:        08/08/2012 07:04 PM 
Subject:        Re: Issue 16951 - time scale subdivides time point -- the confusion continues 

--------------------------------------------------------------------------------



This is a retry at Issue 16951.  It is much simpler than what we were 
trying to do before.
There are still some questions in the margin.

Is this better.

-Ed


Ed Barkmeyer wrote:
> At the last telecon we agreed that time scale subdivides time point may 
> indeed be a specialization of time point converts to time point sequence 
> on time scale.
>
> It appears that that is not true.  In clause 10.8 (beta2), time point 
> converts to time point sequence on time scale, we have
> Definition: the time point is coextensive with the time point sequence
> Possibility:  The time point is an absolute time point or is a relative 
> time point.
> The possibility is redundant:  every time point is either absolute or 
> relative.
> But, together with the Definition, this gives the following much 
> stronger statement:
>  Necessity:  If the time point is an absolute time point, then the time 
> scale is an indefinite time scale.
>  Necessity:  If the time point is a relative time point, then the time 
> scale is a finite time scale.
> These must be so because the time point and the time point sequence are 
> coextensive. 
>
> OTOH, we very much intend that finite time scale subdivides time point 
> can relate a finite time scale to an absolute time point.  We want to 
> allow the year-of-months to subdivide Gregorian year time points, like 
> '2012'.  The time point sequence on the finite time scale need not be 
> co-extensive with the time point; the time point sequence per se could 
> have a much larger extension.  Subdivision is about selecting 
> subintervals in the extension of the time point.  For subdivides, there 
> is a time point sequence that begins with the origin of the finite time 
> scale and that corresponds to every time interval in the extension of 
> the time point (and possible more time intervals).  Within any such time 
> interval, there is a sequence of time intervals, one for each time point 
> in the time point sequence. 
>
> Example: March refers to a large set of time intervals, and 
> month-of-days subdivides March so that day-of-month 3 refers to exactly 
> one 24-hour time interval within each March.  March 2012 corresponds to 
> one time interval and month-of-days subdivides March 2012, so that 
> day-of-month 3 refers to exactly one 24-hour time interval within the 
> March 2012.  In both cases, the subintervals are characterized by being 
> part of a March, having a duration of 1 day (the granularity of 
> month-of-days), and by starting 2 days after the start of the March (the 
> meaning of index 3).  The subdivision is the "being part of a March" 
> characteristic; the rest follows from the definition of the time points. 
>
> We only use the term 'subdivides' in defining time scales.  The finite 
> time scale 'month-of-days' itself is characterized by having every time 
> point defined in terms of its relationship to the start of a calendar 
> month.  So, in one sense, that is all that is meant by 'month-of-days 
> subdivides each calendar month'.  And the 'into 31 day-of-month' part is 
> just a strange way of saying 'month-of-days' has 31 time points and 
> granularity 'day'.  I really think that is all 'subdivides' means, and 
> we should just define it accordingly.  Then March 'converts to' the time 
> point sequence that is on 'month of days', that has 31 time points, and 
> that begins with the origin (which is what we thought we meant by 
> 'subdivides').
>
> The remaining problem is that year 2012 does not 'convert to' a time 
> point sequence on year-of-months, and '1 June 2010' does not 'convert 
> to' a time point sequence on 'day of hours'.  The extensions are different.
>
> So, where do we go from here?
>
> -Ed
>
>
>   

-- 
Edward J. Barkmeyer                        Email: edbark@nist.gov
National Institute of Standards & Technology
Manufacturing Systems Integration Division
100 Bureau Drive, Stop 8263                Tel: +1 301-975-3528
Gaithersburg, MD 20899-8263                Cel: +1 240-672-5800

"The opinions expressed above do not reflect consensus of NIST, 
and have not been reviewed by any Government authority."

[attachment "DTV Issue 16951-time point subdivision-d8.docx" deleted by Mark H Linehan/Watson/IBM] 



-- 
Edward J. Barkmeyer                        Email: edbark@nist.gov
National Institute of Standards & Technology
Manufacturing Systems Integration Division
100 Bureau Drive, Stop 8263                Tel: +1 301-975-3528
Gaithersburg, MD 20899-8263                Cel: +1 240-672-5800

"The opinions expressed above do not reflect consensus of NIST, 
 and have not been reviewed by any Government authority."

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Subject: Re: Issue 16951 - time scale subdivides time point -- the confusion
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My responses like this. 
--------------------------------
Mark H. Linehan
STSM, IBM Research 



From:        Ed Barkmeyer <edbark@nist.gov> 
To:        Mark H Linehan/Watson/IBM@IBMUS, 
Cc:        "date-time-ftf@omg.org" <date-time-ftf@omg.org> 
Date:        08/09/2012 01:16 PM 
Subject:        Re: Issue 16951 - time scale subdivides time point -- the confusion continues 

--------------------------------------------------------------------------------





Mark H Linehan wrote: 
I guess our email about this issue crossed, but I'm not sure it matters. 

Regarding the 'subdivides' verb concept itself, I think we need to specify the kind of time point as a role of the verb concept.  Otherwise, we haven't specified the kind of time points that makeup the finite time scale.  And I think that the kind of time points is intrinsic to the subdivision "function". 

Identifying the finite time scale specifies the kind of time point.  Each time point is on exactly one time scale, and each time scale has exactly one kind of time point.  The time point 'day of month', for example, is defined as:  time point on the month of days time scale. 

Yes, but in this case we are not "identifying the finite time scale", we are "defining it".  For example, if we define 'Gregorian month of days time scale', as "the finite time scale that has granularity 1 day and that has cardinality 31 and that subdivides each 'Gregorian month' into at most 31 time points " then the definition contains now indication of what kind of time point is contained in the time scale.  As a reader, you have to know that the time point must be the one called 'Gregorian day of month'. 

To put it another way, I think we should have two-way links between the scales and the time points because there are so many of each. 


Regarding the definition: I don't think we have (but should have) 'time point sequence on time scale'.  Otherwise, I think the definition goes in the right direction. 

Point taken.  We could define it as a subsequence of the time scale, but that notion is not defined in Annex D.


I still think we can drop "If a finite time scale subdivides a time point into some number time points, " from the start of the Necessities. 
 * We don't do this in other glossary entries.  For example, under 'time point1 through time point2 specifies time period', I see a Necessity "The time scale of time point1 is the time scale of time point2.". 

I think this is an indication that there are errors in the DTV specification.  I forwarded this argument to the SBVR lot.

  * When we use "the" in a Necessity or Definition, the reference is to a role of the verb concept.  See SBVR Annex C.3.2.3. 

Annex C.3.2.3 refers only to the use of placeholder terms within Definitions.  It says nothing about Necessities.  Part of the issue sent to SBVR RTF.  I think this is just overlooked in the discussion of Necessities.  It doesn't say anything to the contrary.

The Example has two formatting errors: (a) alignment of the first line; (b) "into" and "time points" should be in verb style. 

I don't see the alignment error in Word 2007, but it seems to be unable to edit the SBVR paragraph numbering structures that were supported by Word 200x where x < 7.  Instead we have the incompatible and untested 'multilevel list'. 
Yes.

Assuming we keep this, I will correct (b).

Regarding the definitions of 'Gregorian year of months scale' and similar: 
 * Putting just the granularity into the definition does not distinguish among different time points that have the same granularity.  For example, 'Gregorian day of month' and 'Gregorian day of year' have the same granularity.
 * On the other hand, specifying the time point kind implies the granularity since each time point has a particular granularity. 

This is a cart/horse problem.  The time points are defined in terms of the scale, and they get their granularity from it.  The scale is made unique by specifying its granularity and what it subdivides!  That is the whole point of 'subdivides'.  It is an essential property of each finite time scale, and one of its delimiting properties.

(A time scale is not an ad hoc sequence of existing time points that are its members.  The time points are structurally part of the scale; they depend on the scale for their existence, like sequence positions in Annex D.) 
Yes.  As I said above, I think we should have two-way links between the time scales and the time points, for clarity.

  * I think the number of time points in the finite time scale should be a role of the 'subdivides' verb concept because it is intrinsic to the "subdivides" function.  I can see that you agree with me in your comment about the definition of 'Gregorian year of days scale'. 

Well, as you can see in the three cases, they all use the 'number' differently.  So what is intrinsic?  The nature of 'year of months' is to subdivide  'Gregorian year' and it subdivides every Gregorian year into 12 time points.  The nature of 'year of days' is to subdivide 'Gregorian year', but it is stated (instead) to subdivide both common year and leap year and it subdivides them into different numbers of time points. Yes, but 'common year' and 'leap year' are two mutually-disjoint kinds of 'Gregorian year'.  So I don't see a problem.  But we should probably include 'centennial year' and 'quadricentennial year' in the definition to exhaust all the kinds of 'Gregorian year'. 

 The nature of 'month of days' is to subdivide 'Gregorian month' but it is stated to have a variable 'number' of time points.  If it followed the year of days pattern, it would instead have 12 specific variants.  If we specified that January has 31 days, etc., that would help.  But frankly I don't know what to do about February since it varies by year.  Maybe have two variants of February, the 28-day and the 29-day versions?

So I don't think the number is intrinsic to 'subdivides' as a means of defining finite time scales.  The problem is to distinguish between subdividing by nature a class of time points, from doing something to a given time point.  There wouldn't be a distinction if subdivision did the same thing to every such time point.

I notice, however, that there is a problem with 'month of days'.  It seems to me that the 'month of days' time scale can subdivide either/both of 'Gregorian month' (an absolute time point) and 'Gregorian month of year' (a relative time point).  Those time points do not correspond to the same time intervals, but they are both subtypes of an unspecified concept 'Gregorian calendar month'. 
Hmm, good catch.  I agree about creating that unspecified type.

So, I'm not sure what exactly the 'subdivides' idea is.  (I guess I only thought I understood this.)

  * For 'Gregorian month of days scale', I thought we were going to specify the number of time points in each calendar month, month by month.  Although I guess that doesn't work for February. 

OK.  That would almost eliminate the the third kind of subdivision above, but it doesn't generalize to 'G calendar month'.  It is not the nature of 'month of days' to subdivide February; it is the nature of 'month of days' to subdivide 'Gregorian calendar months' as a class, or equivalently any and all.  When 'month of days' is used to subdivide a given calendar month, that is when the n time points appears.

I think there are two ideas:
- a finite time scale is characterized by subdividing1 a category of time points (and every time point in the category), full stop.  The definition of the time points in the scale is based on anchoring the scale on the start of the subdivided time point (suitably phrased).  If we eliminate the cardinality from the proposed definition, it seems to work.  I think you are saying we subdivide into a type of time point and the cardinality of the result is the quotient.  This is not an idea that had occurred to me.
- a finite time scale subdivides2 a specific time point into a specific number of time points (a specific time point sequence).  subdivides2 looks like 'converts to', but the time point sequence per se does not have the same extension.  The intent is to define the component time periods.  And the time point sequence forms only part of the reference scheme for the component time intervals, they all also have to be part of the/a time interval that the subdivided time point corresponds to. This is the idea that I was thinking of.  My comments above are based on this idea.

(The idea of 'converts to' is to turn the time point into a time point sequence that corresponds to exactly the same time intervals, so that you can operate on the time point sequence (in its time scale) to define related time intervals.  The idea of subdivides2 is to use the subdivided time point together with time points in the time point sequence to identify sub-intervals.  I suppose the idea of "using the time point sequence (somehow) to identify related time intervals" is common to both.)

-Ed

--------------------------------
Mark H. Linehan
STSM, IBM Research 



From:        Ed Barkmeyer <edbark@nist.gov> 
To:        "Barkmeyer, Edward J" <edward.barkmeyer@nist.gov>, 
Cc:        OMG DateTimeVoc FTF <date-time-ftf@omg.org> 
Date:        08/08/2012 07:04 PM 
Subject:        Re: Issue 16951 - time scale subdivides time point -- the confusion continues 

--------------------------------------------------------------------------------



This is a retry at Issue 16951.  It is much simpler than what we were 
trying to do before.
There are still some questions in the margin.

Is this better.

-Ed


Ed Barkmeyer wrote:
> At the last telecon we agreed that time scale subdivides time point may 
> indeed be a specialization of time point converts to time point sequence 
> on time scale.
>
> It appears that that is not true.  In clause 10.8 (beta2), time point 
> converts to time point sequence on time scale, we have
> Definition: the time point is coextensive with the time point sequence
> Possibility:  The time point is an absolute time point or is a relative 
> time point.
> The possibility is redundant:  every time point is either absolute or 
> relative.
> But, together with the Definition, this gives the following much 
> stronger statement:
>  Necessity:  If the time point is an absolute time point, then the time 
> scale is an indefinite time scale.
>  Necessity:  If the time point is a relative time point, then the time 
> scale is a finite time scale.
> These must be so because the time point and the time point sequence are 
> coextensive. 
>
> OTOH, we very much intend that finite time scale subdivides time point 
> can relate a finite time scale to an absolute time point.  We want to 
> allow the year-of-months to subdivide Gregorian year time points, like 
> '2012'.  The time point sequence on the finite time scale need not be 
> co-extensive with the time point; the time point sequence per se could 
> have a much larger extension.  Subdivision is about selecting 
> subintervals in the extension of the time point.  For subdivides, there 
> is a time point sequence that begins with the origin of the finite time 
> scale and that corresponds to every time interval in the extension of 
> the time point (and possible more time intervals).  Within any such time 
> interval, there is a sequence of time intervals, one for each time point 
> in the time point sequence. 
>
> Example: March refers to a large set of time intervals, and 
> month-of-days subdivides March so that day-of-month 3 refers to exactly 
> one 24-hour time interval within each March.  March 2012 corresponds to 
> one time interval and month-of-days subdivides March 2012, so that 
> day-of-month 3 refers to exactly one 24-hour time interval within the 
> March 2012.  In both cases, the subintervals are characterized by being 
> part of a March, having a duration of 1 day (the granularity of 
> month-of-days), and by starting 2 days after the start of the March (the 
> meaning of index 3).  The subdivision is the "being part of a March" 
> characteristic; the rest follows from the definition of the time points. 
>
> We only use the term 'subdivides' in defining time scales.  The finite 
> time scale 'month-of-days' itself is characterized by having every time 
> point defined in terms of its relationship to the start of a calendar 
> month.  So, in one sense, that is all that is meant by 'month-of-days 
> subdivides each calendar month'.  And the 'into 31 day-of-month' part is 
> just a strange way of saying 'month-of-days' has 31 time points and 
> granularity 'day'.  I really think that is all 'subdivides' means, and 
> we should just define it accordingly.  Then March 'converts to' the time 
> point sequence that is on 'month of days', that has 31 time points, and 
> that begins with the origin (which is what we thought we meant by 
> 'subdivides').
>
> The remaining problem is that year 2012 does not 'convert to' a time 
> point sequence on year-of-months, and '1 June 2010' does not 'convert 
> to' a time point sequence on 'day of hours'.  The extensions are different.
>
> So, where do we go from here?
>
> -Ed
>
>
>   

-- 
Edward J. Barkmeyer                        Email: edbark@nist.gov
National Institute of Standards & Technology
Manufacturing Systems Integration Division
100 Bureau Drive, Stop 8263                Tel: +1 301-975-3528
Gaithersburg, MD 20899-8263                Cel: +1 240-672-5800

"The opinions expressed above do not reflect consensus of NIST, 
and have not been reviewed by any Government authority."

[attachment "DTV Issue 16951-time point subdivision-d8.docx" deleted by Mark H Linehan/Watson/IBM] 

-- 
Edward J. Barkmeyer                        Email: edbark@nist.gov
National Institute of Standards & Technology
Manufacturing Systems Integration Division
100 Bureau Drive, Stop 8263                Tel: +1 301-975-3528
Gaithersburg, MD 20899-8263                Cel: +1 240-672-5800

"The opinions expressed above do not reflect consensus of NIST, 
and have not been reviewed by any Government authority."

<Down>
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From: Ed Barkmeyer <edbark@nist.gov>
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CC: "date-time-ftf@omg.org" <date-time-ftf@omg.org>
Subject: Re: Issue 16951 - time scale subdivides time point -- the confusion
 continues
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Mark H Linehan wrote: 
My responses like this. 
--------------------------------
Mark H. Linehan
STSM, IBM Research 



From:        Ed Barkmeyer <edbark@nist.gov> 
To:        Mark H Linehan/Watson/IBM@IBMUS, 
Cc:        "date-time-ftf@omg.org" <date-time-ftf@omg.org> 
Date:        08/09/2012 01:16 PM 
Subject:        Re: Issue 16951 - time scale subdivides time point -- the confusion continues 

--------------------------------------------------------------------------------





Mark H Linehan wrote: 
I guess our email about this issue crossed, but I'm not sure it matters. 

Regarding the 'subdivides' verb concept itself, I think we need to specify the kind of time point as a role of the verb concept.  Otherwise, we haven't specified the kind of time points that makeup the finite time scale.  And I think that the kind of time points is intrinsic to the subdivision "function". 
[EJB]
Identifying the finite time scale specifies the kind of time point.  Each time point is on exactly one time scale, and each time scale has exactly one kind of time point.  The time point 'day of month', for example, is defined as:  time point on the month of days time scale. 
[MHL]
Yes, but in this case we are not "identifying the finite time scale", we are "defining it".  For example, if we define 'Gregorian month of days time scale', as "the finite time scale that has granularity 1 day and that has cardinality 31 and that subdivides each 'Gregorian month' into at most 31 time points " then the definition contains now indication of what kind of time point is contained in the time scale.  As a reader, you have to know that the time point must be the one called 'Gregorian day of month'. 


The definition most certainly does contain an indication of what kind of time point is contained in the time scale.  It is a time point that is on the 'Gregorian month of days' time scale and has granularity "1 day".  Is there more information in the definition of 'Gregorian day of month'?  I quote:
 Definition: calendar day that is on the Gregorian month of days scale

Mark's objection seems to be that the definition of the time scale must include the term for the time points.  Otherwise, anyone who doesn't read the next glossary entry won't know that they are called 'Gregorian day of month'.  But knowing what they are called does not actually tell the reader any more about what they are, or about what the time scale is.  There is nothing wrong with putting that information in a Note, but it doesn't form part of the definition of the time scale.  


To put it another way, I think we should have two-way links between the scales and the time points because there are so many of each. 


By definition, Each Gregorian day of month is a time point on the Gregorian month of days scale.  Do you want a Necessity that says:  Each time point of the Gregorian month of days is a Gregorian day of month?

There is a reason for this, but it is subtle.  Having a granularity of "1 day" is not the same thing as being a 'calendar day'.  That is, DTV does not define a relationship between those concepts, and rightfully so, I think.  It is our intention that each Gregorian time point with a granularity of "1 day" is a 'calendar day'.  And we need to say that, because 10.1 says that the Gregorian calendar defines what a Gregorian 'calendar day' is.  

Without that 'axiom', the definition of Gregorian day of month does not preclude the G month of days from having other time points that are not calendar days.  So I agree that the proposed Necessity for G month of days is appropriate.   And given the axiom, the proposed Necessity follows from the definitions.


[MHL]
  * When we use "the" in a Necessity or Definition, the reference is to a role of the verb concept.  See SBVR Annex C.3.2.3. 
[EJB]
Annex C.3.2.3 refers only to the use of placeholder terms within Definitions.  It says nothing about Necessities.  Part of the issue sent to SBVR RTF.  
[MHL]
I think this is just overlooked in the discussion of Necessities.  It doesn't say anything to the contrary.


Why would you assume that a statement made about definitions under the subheading "Definition of a verb concept" would be intended to have a wider scope?

C.1.2 explicitly says that 'the' is:
"1. used with a designation to make a pronominal reference to a previous use of the same designation.
This is formally a binding to a variable of a quantification.
2. introduction of a name of an individual thing or of a definite description"

I have every reason to assume that those are the rules that apply to Necessities and Business Rules, as distinct from Definitions.  Where else would they apply?

What is said to the contrary is that a term like 'time point' refers to the concept it is declared to refer to and denotes the things in its extension.   C.3.2.3 says that when the same expression is a placeholder for a verb role and appears in the definition of that verb concept, then it refers to the thing that plays the verb role in a given state of affairs.  That is pretty clearly intended to be a special case exception.

I moved this discussion to the SBVR RTF exploder, and I want to leave this aspect of the writeup open until there is clear consensus from the SBVR lot.  

[This discussion also appears to have highlighted a bug in RECON.  When a noun concept term is the same expression as a placeholder, both the concept reference and the role reference can appear in a definition.  Annex C says SBVR SE requires 'the' preceding the placeholder, in order to distinguish the cases.  This is clearly Don's algorithm.  Mine is different, but I hadn't thought about two special cases of this problem.]


[MHL]
  * I think the number of time points in the finite time scale should be a role of the 'subdivides' verb concept because it is intrinsic to the "subdivides" function.  I can see that you agree with me in your comment about the definition of 'Gregorian year of days scale'. 
[EJB]
Well, as you can see in the three cases, they all use the 'number' differently.  So what is intrinsic?  The nature of 'year of months' is to subdivide  'Gregorian year' and it subdivides every Gregorian year into 12 time points.  The nature of 'year of days' is to subdivide 'Gregorian year', but it is stated (instead) to subdivide both common year and leap year and it subdivides them into different numbers of time points. 
[MHL]
Yes, but 'common year' and 'leap year' are two mutually-disjoint kinds of 'Gregorian year'.  So I don't see a problem.  


'common year' and 'leap year' are also mutually disjoint kinds of 'time point'.  The question is: what kind of 'time point' does 'year of days' characteristically subdivide?


[MHL]
But we should probably include 'centennial year' and 'quadricentennial year' in the definition to exhaust all the kinds of 'Gregorian year'. 


Ah yes.  Well, that goes to my point that there are two different verbs here -- one that describes the time scale and one that describes the time point sequence.  Like the individual months, these are just rules for the cardinality of the time point sequence for different subtypes of G.year.


[EJB]
 The nature of 'month of days' is to subdivide 'Gregorian month' but it is stated to have a variable 'number' of time points.  If it followed the year of days pattern, it would instead have 12 specific variants.  
[MHL]
If we specified that January has 31 days, etc., that would help.  But frankly I don't know what to do about February since it varies by year.  Maybe have two variants of February, the 28-day and the 29-day versions?


I was addressing this in Issue 16944, I think.  If we think of this as just a rule about the cardinality of the time point sequence, as opposed to part of the definition of 'month of days', then the rule can easily be written formally.


[EJB]
So I don't think the number is intrinsic to 'subdivides' as a means of defining finite time scales.  The problem is to distinguish between subdividing by nature a class of time points, from doing something to a given time point.  There wouldn't be a distinction if subdivision did the same thing to every such time point.

I notice, however, that there is a problem with 'month of days'.  It seems to me that the 'month of days' time scale can subdivide either/both of 'Gregorian month' (an absolute time point) and 'Gregorian month of year' (a relative time point).  Those time points do not correspond to the same time intervals, but they are both subtypes of an unspecified concept 'Gregorian calendar month'. 
[MHL]
Hmm, good catch.  I agree about creating that unspecified type.


Upon reflection, this is another version of defining 'calendar day' for G calendars.  This is defining 'calendar month' for G calendars.  And I think we need to say Gregorian year is a calendar year.

[EJB]
I think there are two ideas:
- a finite time scale is characterized by subdividing1 a category of time points (and every time point in the category), full stop.  The definition of the time points in the scale is based on anchoring the scale on the start of the subdivided time point (suitably phrased).  If we eliminate the cardinality from the proposed definition, it seems to work. 
[MHL]
 I think you are saying we subdivide into a type of time point and the cardinality of the result is the quotient.  This is not an idea that had occurred to me.


That is not the way I thought of it, but it is a way of looking at it.  All I was saying is that the 'into number of time points' is not part of the subdivides1 concept.  That concept is exactly what is formally defined in the last draft of 16951, with the removal of the statement about the cardinality of the time point sequence.  In defining a finite time scale, we do have to say what its cardinality is, but using 'has cardinality'.

When w come to individual time points, or subtypes of the general category being subdivided, then we have 'subdivides2', and the time point sequence has cardinality that is the quotient you describe.


[EJB]
- a finite time scale subdivides2 a specific time point into a specific number of time points (a specific time point sequence).  subdivides2 looks like 'converts to', but the time point sequence per se does not have the same extension.  The intent is to define the component time periods.  And the time point sequence forms only part of the reference scheme for the component time intervals, they all also have to be part of the/a time interval that the subdivided time point corresponds to. 
[MHL]
This is the idea that I was thinking of.  My comments above are based on this idea.


Good.  subdivides2 is what I tried to write in draft 7 as the definition of 'subdivides'.  

If we agree on simplifying 'subdivides 1', back to what it originally was, more or less (!), then I will try to rewrite the first part of this resolution.  

But I'm not quite sure how to phrase 'subdivides2'.  And there will be necessities that use it for each of the individuals and subtypes that have their own time point sequence cardinalities.

-Ed




(The idea of 'converts to' is to turn the time point into a time point sequence that corresponds to exactly the same time intervals, so that you can operate on the time point sequence (in its time scale) to define related time intervals.  The idea of subdivides2 is to use the subdivided time point together with time points in the time point sequence to identify sub-intervals.  I suppose the idea of "using the time point sequence (somehow) to identify related time intervals" is common to both.)

-Ed

--------------------------------
Mark H. Linehan
STSM, IBM Research 



From:        Ed Barkmeyer <edbark@nist.gov> 
To:        "Barkmeyer, Edward J" <edward.barkmeyer@nist.gov>, 
Cc:        OMG DateTimeVoc FTF <date-time-ftf@omg.org> 
Date:        08/08/2012 07:04 PM 
Subject:        Re: Issue 16951 - time scale subdivides time point -- the confusion continues 

--------------------------------------------------------------------------------



This is a retry at Issue 16951.  It is much simpler than what we were 
trying to do before.
There are still some questions in the margin.

Is this better.

-Ed


Ed Barkmeyer wrote:
> At the last telecon we agreed that time scale subdivides time point may 
> indeed be a specialization of time point converts to time point sequence 
> on time scale.
>
> It appears that that is not true.  In clause 10.8 (beta2), time point 
> converts to time point sequence on time scale, we have
> Definition: the time point is coextensive with the time point sequence
> Possibility:  The time point is an absolute time point or is a relative 
> time point.
> The possibility is redundant:  every time point is either absolute or 
> relative.
> But, together with the Definition, this gives the following much 
> stronger statement:
>  Necessity:  If the time point is an absolute time point, then the time 
> scale is an indefinite time scale.
>  Necessity:  If the time point is a relative time point, then the time 
> scale is a finite time scale.
> These must be so because the time point and the time point sequence are 
> coextensive. 
>
> OTOH, we very much intend that finite time scale subdivides time point 
> can relate a finite time scale to an absolute time point.  We want to 
> allow the year-of-months to subdivide Gregorian year time points, like 
> '2012'.  The time point sequence on the finite time scale need not be 
> co-extensive with the time point; the time point sequence per se could 
> have a much larger extension.  Subdivision is about selecting 
> subintervals in the extension of the time point.  For subdivides, there 
> is a time point sequence that begins with the origin of the finite time 
> scale and that corresponds to every time interval in the extension of 
> the time point (and possible more time intervals).  Within any such time 
> interval, there is a sequence of time intervals, one for each time point 
> in the time point sequence. 
>
> Example: March refers to a large set of time intervals, and 
> month-of-days subdivides March so that day-of-month 3 refers to exactly 
> one 24-hour time interval within each March.  March 2012 corresponds to 
> one time interval and month-of-days subdivides March 2012, so that 
> day-of-month 3 refers to exactly one 24-hour time interval within the 
> March 2012.  In both cases, the subintervals are characterized by being 
> part of a March, having a duration of 1 day (the granularity of 
> month-of-days), and by starting 2 days after the start of the March (the 
> meaning of index 3).  The subdivision is the "being part of a March" 
> characteristic; the rest follows from the definition of the time points. 
>
> We only use the term 'subdivides' in defining time scales.  The finite 
> time scale 'month-of-days' itself is characterized by having every time 
> point defined in terms of its relationship to the start of a calendar 
> month.  So, in one sense, that is all that is meant by 'month-of-days 
> subdivides each calendar month'.  And the 'into 31 day-of-month' part is 
> just a strange way of saying 'month-of-days' has 31 time points and 
> granularity 'day'.  I really think that is all 'subdivides' means, and 
> we should just define it accordingly.  Then March 'converts to' the time 
> point sequence that is on 'month of days', that has 31 time points, and 
> that begins with the origin (which is what we thought we meant by 
> 'subdivides').
>
> The remaining problem is that year 2012 does not 'convert to' a time 
> point sequence on year-of-months, and '1 June 2010' does not 'convert 
> to' a time point sequence on 'day of hours'.  The extensions are different.
>
> So, where do we go from here?
>
> -Ed
>
>
>   

-- 
Edward J. Barkmeyer                        Email: edbark@nist.gov
National Institute of Standards & Technology
Manufacturing Systems Integration Division
100 Bureau Drive, Stop 8263                Tel: +1 301-975-3528
Gaithersburg, MD 20899-8263                Cel: +1 240-672-5800

"The opinions expressed above do not reflect consensus of NIST, 
and have not been reviewed by any Government authority."

[attachment "DTV Issue 16951-time point subdivision-d8.docx" deleted by Mark H Linehan/Watson/IBM] 

-- 
Edward J. Barkmeyer                        Email: edbark@nist.gov
National Institute of Standards & Technology
Manufacturing Systems Integration Division
100 Bureau Drive, Stop 8263                Tel: +1 301-975-3528
Gaithersburg, MD 20899-8263                Cel: +1 240-672-5800

"The opinions expressed above do not reflect consensus of NIST, 
and have not been reviewed by any Government authority."




-- 
Edward J. Barkmeyer                        Email: edbark@nist.gov
National Institute of Standards & Technology
Manufacturing Systems Integration Division
100 Bureau Drive, Stop 8263                Tel: +1 301-975-3528
Gaithersburg, MD 20899-8263                Cel: +1 240-672-5800

"The opinions expressed above do not reflect consensus of NIST, 
 and have not been reviewed by any Government authority."

Date: Thu, 16 Aug 2012 17:44:27 -0400
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All,

I offer yet another draft (9) for resolving this issue.  I think this draft finally covers the whole ground.  It addresses everything in the last two discussions.  And I hope it covers all of Mark's concerns.

When trying to implement the results of Monday's telecon, I noticed that the wording actually used in defining Gmonth time points in 11.3 (N.S.  ) for 'converts to' is 'has number of'.  So I defined it.  The definition is not equivalent to 'converts to', so we need to decide whether they need to be different.

I also made an attempt at handling the February problem.  The difficulty with the solution discussed in the telecon is that there is only one February time point.  It can have subtypes, but the subtypes are not time points -- they don't appear on any time scale.  And since they are not time points, they don't 'convert to' anything.

In implementing the change, I repaired the 'month of year' error that we noted, and a few others.

I still need to create a revised UML diagram.

I think this will need another revision, but I do think we finally understand all the issues.  

-Ed



-- 
Edward J. Barkmeyer                        Email: edbark@nist.gov
National Institute of Standards & Technology
Manufacturing Systems Integration Division
100 Bureau Drive, Stop 8263                Tel: +1 301-975-3528
Gaithersburg, MD 20899-8263                Cel: +1 240-672-5800

"The opinions expressed above do not reflect consensus of NIST, 
 and have not been reviewed by any Government authority."



 DTV Issue 16951-time point subdivision-d9.docx <Down>
<Down>
<Down>
Disposition: Resolved
OMG Issue No:  16951
Title:	Time point subdivision is out of place twice
Source:  Ed Barkmeyer, NIST, edbark@nist.gov

Summary:
At the end of section 9.3 the fact type 'finite time scale subdivides time point' is defined and depicted in Figure 9-6.  This fact type is a commonly used property of finite time scales, and is not specific to individual time points.  That is, the finite time scale day-of-hours subdivides every day-of-month, for example.  So the text and diagram should be at the end of 9.2, where finite time scale is defined. 
Also, diagram 9-6 does not show the operations on time point and finite time scale that are associated with this fact type and shown in diagram 12-12.
Finally, diagram 12-12 (section 12.4) shows this fact type as well, but section 12.4 never uses it, and diagram 12-12 shows a <<specialization>> relationship that is never discussed anywhere in the text.  If the relationship is important, it should be discussed.  Otherwise, the subdivision association is out of place in diagram 12-12 and the "specialization" dependency should be deleted from the UML model.
Recommendation: Move the diagram and text for 'finite time scale subdivides time point' to the end of 9.2, include the operations on the diagram.  Delete the fact type from diagram 12-12, and delete the "specialization" dependency altogether.

Resolution:
The FTF agrees that the fact-type 'finite time scale subdivides time point' should be moved, along with Figure 9-6, but it depends on concepts defined in 9.3 and 9.4. It is an important concept that should have its own subsection.  This concept is used only in defining finite time scales within Calendars.  So the new section goes in clause 10 (formerly 9.5) Calendars.  
The verb concept 'finite time scale subdivides time point' is not quite the way it is used.  All of the existing usages have the form:  'finite time scale subdivides time point into number of time point kind.'  But the finite time scale determines the time point kind, so that is redundant.  Also, it is not clear whether the intent is to specify the cardinality of the finite time scale or the cardinality of the time point sequence that is the subdivision of individual time points, such as months of the year.  The text is revised to clarify that.  
The concept in diagram 10.14 (formerly 12.12) . time point converts to time point sequence on time scale . is only distantly related.  The nature of the time point sequences involved is different, and the purposes are different.  The purpose of time point subdivision is to be part of the definition of finite time scales.  Diagram 10.14 (formerly 12.12) no longer shows the "specialization"; it was removed by resolution of another issue.  

Revised Text:
1.  At the end of 8.5 (was 9.3), DELETE Figure 8.18 (was 9.6) and the following text:
(Figure 8.18)
Figure 8.18: Time Scale Subdivision
finite time scale subdivides time point
Definition:	the finite time scale divides the time point into a number of time intervals that each have a duration, and the number is the cardinality of the finite time scale, and the duration is the granularity of the finite time scale
Example:	The day of hours scale subdivides the Gregorian date 3 January 2010 into 24 time intervals, each of duration "hour"

2.  Immediately before section 10.3 (was 9.5), create a new subsection numbered 10.3, and renumber the subsequent sections: 
10.3  Time Point Subdivision
The purpose of finite time scales is to provide finer-grained resolution of time intervals within the time intervals that are instances of time points with coarser granularities.  In this specification, the relationship between a finite time scale and a coarser time point is called .time point subdivision..  Many finite time scales are defined by the category of time point they subdivide and the granularity of the time points they contain.
 
Figure 10.x: Time Point Subdivision
time point kind 
Definition:	concept that is a specialization of the concept 'time point'
Concept Type:	categorization type
finite time scale subdivides time point kind 
Definition:	for each time point that is an instance of time point kind, there is a set of time point sequences  that are on the finite time scale, and
  the first time point of each time point sequence that is in the set is the index origin member of the finite time scale, and
  each time interval that is an instance of the time point is an instance of some time point sequence that is in the set
Note:	This verb concept describes the purpose of the finite time scale:  each time point of the finite time scale corresponds to time intervals according to their position relative to the start of a time interval that is an instance of some time point of the time point kind.  The first time point of the finite time scale corresponds to time intervals that start the larger time intervals and have a duration equal to the granularity of the finite time scale.
Note:	For most time point subdivisions, the "set of time point sequences" has exactly one member . one time point sequence corresponds to all instances of the time point.  The sole exception is the time point February.
Necessity:	The granularity of each finite time scale is less than the granularity of each time point that is an instance of the time point kind that the finite time scale subdivides. 
Note:	The time point sequence may correspond to many more time intervals than the instances of such time points.  
Note:	The finite time scale may subdivide all time points of a kind into the same  time point sequence or it may subdivide different time points into time point sequences of different lengths.  
Example:	The day of hours scale subdivides Gregorian calendar day. Every time point that is a Gregorian calendar day is subdivided  into 24 hour of day time points, and each corresponding time interval is divided into 24 time intervals, each of which is an instance of one hour-of-day.  
Example:	The Gregorian month of days scale subdivides month of year. Every time point that is a Gregorian month of year is subdivided  into some number of day of month time points, and the time point sequences all begin with day of month 1, but the length of the time point sequence depends on which month time point is subdivided.  
time point has number of time point kind  
Definition:	there is a time point sequence that is on the finite time scale that each instance of the time point kind is a member of, and
  the first time point of the time point sequence is the index origin member of the finite time scale, and
  the cardinality of the time point sequence is number, and
  the time point sequence corresponds to each time interval that is an instance of time point
Note:	This verb concept describes the relationship between the finite time scale and an individual time point of the kind that the finite time scale subdivides.  That is, it completely specifies the subdividing time point sequence.
Necessity:	If a time point has some number of time point kind1, the finite time scale that each instance of time point kind1 is a member of subdivides the time point kind2 that the time point is an instance of.
Example:	Gregorian day 3 January 2010 is subdivided by the day of hours scale into 24 time points.  The time interval corresponding to Gregorian date 3 January 2010 is implicitly subdivided into 24 time intervals, each of which is an instance of one hour-of-day.  But that same 24-hour time point sequence is the subdivision of every Gregorian day, and it corresponds to every Gregorian day time interval.
finite time scale exactly subdivides time point kind  
Definition:	for each time point that is an instance of time point kind, the time point sequence that is the finite time scale corresponds to each time interval that is an instance of the time point 
Necessity:	Each finite time scale that exactly subdivides a time point kind subdivides the time point kind.
Necessity:	If a finite time scale exactly subdivides time point kind1, and each time point of the finite time scale is an instance of time point kind2, then the number of time point kind2 that each time point that is an instance of time point kind1 has  is the cardinality of the finite time scale.
Example:	The day of hours scale exactly subdivides Gregorian day of month.  Every Gregorian day of month therefore has 24 of 'hour of day', because 24 is the cardinality of 'day of hours'.

3.  In clause 11.1 (was 9.5.5), in the entry for 'Gregorian year of months scale', REPLACE the Definition and the first Necessity:
Definition:	the finite time scale that subdivides .Gregorian year. into 12 of .Gregorian month of year.
Necessity:	The granularity of the Gregorian year of months scale is .month..
with:
Definition:	the finite time scale that has granularity 1 month and that has cardinality 12 and that exactly subdivides 'Gregorian year'
Necessity:	Each Gregorian year is subdivided into a the same sequence of  12 Gregorian month of year time points.
4.  In clause 11.1 (was 9.5.5), in the entry for 'Gregorian year of days scale', REPLACE the Definition and the first Necessity:
Definition:	the finite time scale that subdivides .Gregorian year. into 366 of .Gregorian day of year.
Necessity:	The granularity of the Gregorian year of days scale is .day..
with:
Definition:	the finite time scale that has granularity 1 day and that has cardinality 366 and that subdivides 'Gregorian year'
Note:	Each leap year is subdivided into 366 Gregorian day of year time points. Each common year is subdivided into 365 Gregorian day of year time points.
5.  In clause 11.1 (was 9.5.5), in the entry for 'Gregorian month of days scale', REPLACE the Definition and the first Necessity:
Definition:	the finite time scale that subdivides .Gregorian month. into 31 of .Gregorian day of month.
Necessity:	The granularity of the Gregorian month of days scale is .day..
with:
Definition:	the finite time scale that has granularity 1 day and that has cardinality 31 and that subdivides 'Gregorian month of year'
Note:	Each Gregorian month of year is subdivided into a specific number of Gregorian day of month time points.  The subdivision of February is a set of two time sequences.
6. In clause 11.2, in the entry for 'common year', after the Definition paragraph, ADD:
Necessity:	Each common year has 365 of 'Gregorian day of year'.
7. In clause 11.2, in the entry for 'leap year', after the Definition paragraph, ADD:
Necessity:	Each leap year has 366 of 'Gregorian day of year'.
8.  In clause 11.2, before the entry for Gregorian day, INSERT a new entry:
Gregorian calendar month 
Definition:	Gregorian month or Gregorian month of year
9.  In clause 11.2, at the end, ADD a new entry:
Gregorian calendar day 
Definition:	Gregorian day or Gregorian day of year or Gregorian day of month or Gregorian day of week
10.  [Note to Editor:  There is a pattern to these changes:  For all but February, insert "of '" between the number and the term that follows it, and follow the term with a closing single quote (').
10a. In clause 11.3, in the entry for January, REPLACE the Necessity that reads:
Necessity:	January has 31 Gregorian days of month.
with
Necessity:	January has 31 of 'Gregorian day of month'.
10b. In clause 11.3, in the entry for February, REPLACE the Necessities that read:
Necessity:	If the Gregorian year is a common year, then February has 28 Gregorian days of month.
Necessity:	If the Gregorian year is a leap year, then February has 29 Gregorian days of month.
with:
Necessity:	The number of 'Gregorian day of month' that February has is 28 or 29. 
Necessity:	The time point sequence that is Gregorian day of month 1 through Gregorian day of month 28 corresponds to each February that is during a common year.
Necessity:	The time point sequence that is Gregorian day of month 1 through Gregorian day of month 29 corresponds to each February that is during a leap year.
Note:	The set of these two time point sequences is how Gregorian month of days subdivides February.
10c. In clause 11.3, in the entry for March, REPLACE the Necessity that reads:
Necessity:	March has 31 Gregorian days of month.
with
Necessity:	March has 31 of 'Gregorian day of month'.
10d. In clause 11.3, in the entry for April, REPLACE the Necessity that reads:
Necessity:	April has 30 Gregorian days of month.
with
Necessity:	April has 30 of 'Gregorian day of month'.
10e. In clause 11.3, in the entry for May, REPLACE the Necessity that reads:
Necessity:	May has 31 Gregorian days of month.
with
Necessity:	May has 31 of 'Gregorian day of month'.
10f. In clause 11.3, in the entry for June, REPLACE the Necessity that reads:
Necessity:	June has 30 Gregorian days of month.
with
Necessity:	June has 30 of 'Gregorian day of month'.
10g. In clause 11.3, in the entry for July, REPLACE the Necessity that reads:
Necessity:	July has 31 Gregorian days of month.
with
Necessity:	July has 31 of 'Gregorian day of month'.
10h. In clause 11.3, in the entry for August, REPLACE the Necessity that reads:
Necessity:	August has 31 Gregorian days of month.
with
Necessity:	August has 31 of 'Gregorian day of month'.
10i. In clause 11.3, in the entry for September, REPLACE the Necessity that reads:
Necessity:	September has 30 Gregorian days of month.
with
Necessity:	September has 30 of 'Gregorian day of month'.
10j. In clause 11.3, in the entry for October, REPLACE the Necessity that reads:
Necessity:	October has 31 Gregorian days of month.
with
Necessity:	October has 31 of 'Gregorian day of month'.
10k. In clause 11.3, in the entry for November, REPLACE the Necessity that reads:
Necessity:	November has 30 Gregorian days of month.
with
Necessity:	November has 30 of 'Gregorian day of month'.
10l. In clause 11.3, in the entry for December, REPLACE the Necessity that reads:
Necessity:	December has 31 Gregorian days of month.
with
Necessity:	December has 31 of 'Gregorian day of month'.

11.  In clause 12.2, in the entry for week of days scale, REPLACE the Definition and the first Necessity:
Definition:	the finite time scale that subdivides .calendar week. into 7 of .calendar day.
Necessity:	The granularity of the week of days scale is .day..
with:
Definition:	the finite time scale that has granularity 1 day and that has cardinality 7 and that exactly subdivides 'calendar week'
Necessity:	Each calendar week has 7 of 'day of week'.

12.  In clause 13.1, in the entry for day of hours scale, REPLACE the Definition and the first Necessity:
Definition:	the finite time scale of 24 .hour of day.
Necessity:	The granularity of the day of hours scale is .hour..
with:
Definition:	the finite time scale that has granularity 1 hour and that has cardinality 24 and that exactly subdivides 'Gregorian calendar day'
Necessity:	Each calendar day has 24 of 'hour of day'.
13.  In clause 13.1, in the entry for day of minutes scale, REPLACE the Definition and the first Necessity:
Definition:	the finite time scale that subdivides each calendar day into 1440 .minute of day.
Necessity:	The granularity of the day of minutes scale is .minute..
with:
Definition:	the finite time scale that has granularity 1 minute and that has cardinality 1440 and that exactly subdivides 'Gregorian calendar day'
Necessity:	Each calendar day has 1440 of 'minute of day'.

14.  In clause 13.1, in the entry for day of seconds scale, REPLACE the Definition, the following Note and the first Necessity:
Definition:	the finite time scale that subdivides each calendar day into at most 86401 .second of day.
Note:	The second of day with index 86400 corresponds only to leap seconds. Because of leap seconds, a calendar day can have a duration of 86399, 86400, or 86401 seconds. 
Necessity:	The granularity of the day of seconds scale is .second..
with:
Definition:	the finite time scale that has granularity 1 second and that has cardinality 86400 and that exactly subdivides 'Gregorian calendar day'
Necessity:	Each calendar day has 86400 of 'second of day'.

15.  In clause 13.1, in the entry for hour of minutes scale, REPLACE the Definition and the first Necessity:
Definition:	the finite time scale that subdivides each minute of hour into 60 .minute of hour.
Necessity:	The granularity of the hour of minutes scale is .minute..
with:
Definition:	the finite time scale that has granularity 1 minute and that has cardinality 60 and that exactly subdivides 'minute of hour'
Necessity:	Each hour of day has 60 of 'minute of hour'.

16.  In clause 13.1, in the entry for minute of seconds scale, REPLACE the Definition, the following Note and the first Necessity:
Definition:	the finite time scale that subdivides each minute of day into at most 61 .second of minute.
Note:	The second of minute with index 60 corresponds only to leap seconds. Because of leap seconds, a minute of hour 59 can have a duration of 59, 60, or 61 seconds. 
Necessity:	The granularity of the minute of seconds scale is .second..
with:
Definition:	the finite time scale that has granularity 1 second and that has cardinality 60 and that exactly subdivides 'minute of hour'
Necessity:	Each minute of hour has 60 of 'second of minute'.


Disposition:	Resolved





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Subject: Re: DTV Issue 16951 - time point subdivision -- are we there yet?
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Overall, I think the design is good. 

My main comment is that I don't like Definitions and Necessities that read like CLIF axioms. We can discuss them during the next conference call. 

It sounds like 'finite time scale exactly subdivides time point kind' is a specialization of 'finite time scale subdivides time point'. 

Minor comments: 

* 'concept type' should be styled in the glossary entry for 'time point kind' 
* We should consistently style vocabulary references in Notes. 
* The formatting of the "Example" captions is messed up. 
* I don't understand this Note: "The finite time scale may subdivide all time points of a kind into the same  time point sequence or it may subdivide different time points into time point sequences of different lengths" 
* In the Definition of "time point has number of time point kind", the reference to 'finite time scale' should be to 'time point sequence' (??) 
* The Example under "time point has number of time point kind" is not an example of that verb concept 
* I don't understand the Necessity "Each Gregorian year is subdivided into a the same sequence of  12 Gregorian month of year time points." 
* Why did you put this into a Note rather than the Definition of 'Gregorian year of days scale':  "Each leap year is subdivided into 366 Gregorian day of year time points. Each common year is subdivided into 365 Gregorian day of year time points." 
* The new glossary entries for 'Gregorian calendar month' and 'Gregorian calendar day' should be marked 'concept type'.  And we need a new version of figure 11.3. 
* What about the 'year of weekdays scale' and the 'year of weeks scale' 

--------------------------------
Mark H. Linehan
STSM, IBM Research 



From:        Ed Barkmeyer <edbark@nist.gov> 
To:        OMG DateTimeVoc FTF <date-time-ftf@omg.org>, 
Date:        08/16/2012 05:48 PM 
Subject:        DTV Issue 16951 - time point subdivision -- are we there yet? 

--------------------------------------------------------------------------------



All,

I offer yet another draft (9) for resolving this issue.  I think this draft finally covers the whole ground.  It addresses everything in the last two discussions.  And I hope it covers all of Mark's concerns.

When trying to implement the results of Monday's telecon, I noticed that the wording actually used in defining Gmonth time points in 11.3 (N.S.  ) for 'converts to' is 'has number of'.  So I defined it.  The definition is not equivalent to 'converts to', so we need to decide whether they need to be different.

I also made an attempt at handling the February problem.  The difficulty with the solution discussed in the telecon is that there is only one February time point.  It can have subtypes, but the subtypes are not time points -- they don't appear on any time scale.  And since they are not time points, they don't 'convert to' anything.

In implementing the change, I repaired the 'month of year' error that we noted, and a few others.

I still need to create a revised UML diagram.

I think this will need another revision, but I do think we finally understand all the issues.  

-Ed


-- 
Edward J. Barkmeyer                        Email: edbark@nist.gov
National Institute of Standards & Technology
Manufacturing Systems Integration Division
100 Bureau Drive, Stop 8263                Tel: +1 301-975-3528
Gaithersburg, MD 20899-8263                Cel: +1 240-672-5800

"The opinions expressed above do not reflect consensus of NIST, 
and have not been reviewed by any Government authority."
[attachment "DTV Issue 16951-time point subdivision-d9.docx" deleted by Mark H Linehan/Watson/IBM] 
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Mark H Linehan wrote: 
Overall, I think the design is good. 

My main comment is that I don't like Definitions and Necessities that read like CLIF axioms. We can discuss them during the next conference call. 


Yes.  If you want to propose rewordings, fine.  


It sounds like 'finite time scale exactly subdivides time point kind' is a specialization of 'finite time scale subdivides time point'. 


Of course, the Necessity makes that clear.  And the UML generalization is drawn in the revised diagram (attached).  Do you also want a Note to that effect?  The first question is:  Do we all agree that exactly subdivides is important/useful?


Minor comments: 

* 'concept type' should be styled in the glossary entry for 'time point kind' 
* We should consistently style vocabulary references in Notes. 


Fine.  I wouldn't mind styling terms in a Note if the term were just underscored in the Times Roman text, but making every term in a Note appear in 25% larger Arial (not Helvetic) teal interrupts the flow of reading.  And the purpose of a Note is to explain something to readers, not tools.


* The formatting of the "Example" captions is messed up. 


Not in Word 2010, and not in the PDF it generates.


* I don't understand this Note: "The finite time scale may subdivide all time points of a kind into the same  time point sequence or it may subdivide different time points into time point sequences of different lengths" 


I revised the wording.


* In the Definition of "time point has number of time point kind", the reference to 'finite time scale' should be to 'time point sequence' (??) 


In the Definition, there are two references that use the term 'finite time scale'.  The first is in a definite description of a specific instance of 'finite time scale'.  The second is a 'back reference' to the first, using the term 'the finite time scale', as described in Annex C.  (Mark prefers subscripting these things, and then says he doesn't like definitions that read like CLIF.)

I'm not married to any of this.  I just tried to define the verb form that the existing text used in many Necessities.  And, of course, it had the flavor of what I called 'subdivides2'.  


* The Example under "time point has number of time point kind" is not an example of that verb concept 


Fixed.  I copied the Example from above, intending to rework it, and then forgot to.


* I don't understand the Necessity "Each Gregorian year is subdivided into a the same sequence of  12 Gregorian month of year time points." 


Rewritten formally.  The Necessity follows from 'exactly'.  I think this was a Note that Word guessed the wrong caption for.  I was trying to show the difference between year of months and year of days.  One subdivision always uses the same time point sequence; the other uses different ones at different times.


* Why did you put this into a Note rather than the Definition of 'Gregorian year of days scale':  "Each leap year is subdivided into 366 Gregorian day of year time points. Each common year is subdivided into 365 Gregorian day of year time points." 


It is a Note here, because (a) it goes beyond the Definition, but (b) it shows that this is a case where the finite time scale subdivides different time points differently.  That is why this subdivision is not 'exactly subdivides'.  These two sentences are Necessities under leaip year and common year.

[Aside:  Something is wrong with the leap year, common year, etc. definitions.  A quadricentennial year is a centennial year, by definition.  I think centennial years break down into common centennial years and quadricentennial years.]


* The new glossary entries for 'Gregorian calendar month' and 'Gregorian calendar day' should be marked 'concept type'.  


Done.


And we need a new version of figure 11.3. 


Yes, and possibly others.  


* What about the 'year of weekdays scale' and the 'year of weeks scale' 


I thought we agreed to work those under a separate issue.  I added that note to the Resolution text.

-Ed


--------------------------------
Mark H. Linehan
STSM, IBM Research 



From:        Ed Barkmeyer <edbark@nist.gov> 
To:        OMG DateTimeVoc FTF <date-time-ftf@omg.org>, 
Date:        08/16/2012 05:48 PM 
Subject:        DTV Issue 16951 - time point subdivision -- are we there yet? 

--------------------------------------------------------------------------------



All,

I offer yet another draft (9) for resolving this issue.  I think this draft finally covers the whole ground.  It addresses everything in the last two discussions.  And I hope it covers all of Mark's concerns.

When trying to implement the results of Monday's telecon, I noticed that the wording actually used in defining Gmonth time points in 11.3 (N.S.  ) for 'converts to' is 'has number of'.  So I defined it.  The definition is not equivalent to 'converts to', so we need to decide whether they need to be different.

I also made an attempt at handling the February problem.  The difficulty with the solution discussed in the telecon is that there is only one February time point.  It can have subtypes, but the subtypes are not time points -- they don't appear on any time scale.  And since they are not time points, they don't 'convert to' anything.

In implementing the change, I repaired the 'month of year' error that we noted, and a few others.

I still need to create a revised UML diagram.

I think this will need another revision, but I do think we finally understand all the issues.  

-Ed


-- 
Edward J. Barkmeyer                        Email: edbark@nist.gov
National Institute of Standards & Technology
Manufacturing Systems Integration Division
100 Bureau Drive, Stop 8263                Tel: +1 301-975-3528
Gaithersburg, MD 20899-8263                Cel: +1 240-672-5800

"The opinions expressed above do not reflect consensus of NIST, 
and have not been reviewed by any Government authority."
[attachment "DTV Issue 16951-time point subdivision-d9.docx" deleted by Mark H Linehan/Watson/IBM] 



-- 
Edward J. Barkmeyer                        Email: edbark@nist.gov
National Institute of Standards & Technology
Manufacturing Systems Integration Division
100 Bureau Drive, Stop 8263                Tel: +1 301-975-3528
Gaithersburg, MD 20899-8263                Cel: +1 240-672-5800

"The opinions expressed above do not reflect consensus of NIST, 
 and have not been reviewed by any Government authority."



 DTV Issue 16951-time point subdivision-d10.docx 
<Down>
Disposition: Resolved
OMG Issue No:  16951
Title:	Time point subdivision is out of place twice
Source:  Ed Barkmeyer, NIST, edbark@nist.gov

Summary:
At the end of section 9.3 the fact type 'finite time scale subdivides time point' is defined and depicted in Figure 9-6.  This fact type is a commonly used property of finite time scales, and is not specific to individual time points.  That is, the finite time scale day-of-hours subdivides every day-of-month, for example.  So the text and diagram should be at the end of 9.2, where finite time scale is defined. 
Also, diagram 9-6 does not show the operations on time point and finite time scale that are associated with this fact type and shown in diagram 12-12.
Finally, diagram 12-12 (section 12.4) shows this fact type as well, but section 12.4 never uses it, and diagram 12-12 shows a <<specialization>> relationship that is never discussed anywhere in the text.  If the relationship is important, it should be discussed.  Otherwise, the subdivision association is out of place in diagram 12-12 and the "specialization" dependency should be deleted from the UML model.
Recommendation: Move the diagram and text for 'finite time scale subdivides time point' to the end of 9.2, include the operations on the diagram.  Delete the fact type from diagram 12-12, and delete the "specialization" dependency altogether.

Resolution:
The FTF agrees that the fact-type 'finite time scale subdivides time point' should be moved, along with Figure 9-6, but it depends on concepts defined in 9.3 and 9.4. It is an important concept that should have its own subsection.  This concept is used only in defining finite time scales within Calendars.  So the new section goes in clause 10 (formerly 9.5) Calendars.  
The verb concept 'finite time scale subdivides time point' is not quite the way it is used.  All of the existing usages have the form:  'finite time scale subdivides time point into number of time point kind.'  But the finite time scale determines the time point kind, so that is redundant.  Also, it is not clear whether the intent is to specify the cardinality of the finite time scale or the cardinality of the time point sequence that is the subdivision of individual time points, such as months of the year.  The text is revised to clarify that.  distinguish subdivides as a characteristic of finite time scales from the specification of the actual time point sequences used to subdivide individual time points.  The term exactly subdivides is used when all the time points have the same subdivision; and the special cases use the (now defined) verb 'time point has number of time point kind' that was already present in the entries for the special cases.
Note:  This clarification was not applied to the 'year of weeks' and 'year of weekdays' time scales, whose nature is addressed by a different issue.  Simply stated, the year of weeks does not subdivide a calendar year.
The concept in diagram 10.14 (formerly 12.12) . time point converts to time point sequence on time scale . is only distantly related.  The nature of the time point sequences involved is different, and the purposes are different.  The purpose of time point subdivision is to be part of the definition of finite time scales.  Diagram 10.14 (formerly 12.12) no longer shows the "specialization"; it was removed by resolution of another issue.  

Revised Text:
1.  At the end of 8.5 (was 9.3), DELETE Figure 8.18 (was 9.6) and the following text:
(Figure 8.18)
Figure 8.18: Time Scale Subdivision
finite time scale subdivides time point
Definition:	the finite time scale divides the time point into a number of time intervals that each have a duration, and the number is the cardinality of the finite time scale, and the duration is the granularity of the finite time scale
Example:	The day of hours scale subdivides the Gregorian date 3 January 2010 into 24 time intervals, each of duration "hour"

2.  Immediately before section 10.3 (was 9.5), create a new subsection numbered 10.3, and renumber the subsequent sections: 
10.3  Time Point Subdivision
The purpose of finite time scales is to provide finer-grained resolution of time intervals within the time intervals that are instances of time points with coarser granularities.  In this specification, the relationship between a finite time scale and a coarser time point is called .time point subdivision..  Many finite time scales are defined by the category of time point they subdivide and the granularity of the time points they contain.
 
Figure 10.x: Time Point Subdivision
time point kind 
Definition:	concept that is a specialization of the concept 'time point'
Concept Type:	categorization type
finite time scale subdivides time point kind 
Definition:	for each time point that is an instance of time point kind, there is a set of time point sequences  that are on the finite time scale, and
  the first time point of each time point sequence that is in the set is the index origin member of the finite time scale, and
  each time interval that is an instance of the time point is an instance of some time point sequence that is in the set
Note:	This verb concept describes the purpose of the finite time scale:  each time point of the finite time scale corresponds to time intervals according to their position relative to the start of a time interval that is an instance of some time point of the time point kind.  The first time point of the finite time scale corresponds to time intervals that start the larger time intervals and have a duration equal to the granularity of the finite time scale.
Note:	For most time point subdivisions, the "set of time point sequences" has exactly one member . one time point sequence corresponds to all instances of the time point.  The sole exception is the time point February.
Necessity:	The granularity of each finite time scale is less than the granularity of each time point that is an instance of the time point kind that the finite time scale subdivides. 
Note:	The time point sequence may correspond to many more time intervals than the instances of such time points.  
Note:	The finite time scale may subdivide all time points of a kind into the same  time point sequence or it may subdivide different time points The same  time point sequence may be the subdivision of all time points the time point kind, or different time points may be subdivided into time point sequences of different lengths.  
Example:	The day of hours scale subdivides Gregorian calendar day. Every time point that is a Gregorian calendar day is subdivided  into 24 hour of day time points, and each corresponding time interval is divided into 24 time intervals, each of which is an instance of one hour- of- day.  
Example:	The Gregorian month of days scale subdivides month of year. Every time point that is a Gregorian month of year is subdivided  into some number of day of month time points, and the time point sequences all begin with day of month 1, but the length of the time point sequence depends on which month time point is subdivided.  
time point has number of time point kind  
Definition:	there is a time point sequence that is on the finite time scale that each instance of the time point kind is a member of, and
  the first time point of the time point sequence is the index origin member of the finite time scale, and
  the cardinality of the time point sequence is number, and
  the time point sequence corresponds to each time interval that is an instance of time point
Note:	This verb concept describes the relationship between the finite time scale and an individual time point of the kind that the finite time scale subdivides.  That is, it completely specifies the subdividing time point sequence.
Necessity:	If a time point has some number of time point kind1, the finite time scale that each instance of time point kind1 is a member of subdivides the time point kind2 that the time point is an instance of.
Example:	Gregorian day 3 January 2010 is subdivided by the day of hours scale intohas 24 'hour of day' time points.  The time interval corresponding to Gregorian date 3 January 2010 is implicitly subdivided into 24 time intervals, each of which is an instance of one hour- of- day.  But that same 24-hour time point sequence is the subdivision of every Gregorian day, and it corresponds to every time interval that is an instance of a Gregorian day time interval.
finite time scale exactly subdivides time point kind  
Definition:	for each time point that is an instance of time point kind, the time point sequence that is the finite time scale corresponds to each time interval that is an instance of the time point 
Necessity:	Each finite time scale that exactly subdivides a time point kind subdivides the time point kind.
Necessity:	If a finite time scale exactly subdivides time point kind1, and each time point of the finite time scale is an instance of time point kind2, then the number of time point kind2 that each time point that is an instance of time point kind1 has  is the cardinality of the finite time scale.
Example:	The day of hours scale exactly subdivides Gregorian day of month.  Every Gregorian day of month therefore has 24 of 'hour of day', because 24 is the cardinality of 'day of hours'.

3.  In clause 11.1 (was 9.5.5), in the entry for 'Gregorian year of months scale', REPLACE the Definition and the first Necessity:
Definition:	the finite time scale that subdivides .Gregorian year. into 12 of .Gregorian month of year.
Necessity:	The granularity of the Gregorian year of months scale is .month..
with:
Definition:	the finite time scale that has granularity 1 month and that has cardinality 12 and that exactly subdivides 'Gregorian year'
Necessity:	Each Gregorian year is subdivided into a the same sequence of  has 12 of Gregorian month of year time points.
4.  In clause 11.1 (was 9.5.5), in the entry for 'Gregorian year of days scale', REPLACE the Definition and the first Necessity:
Definition:	the finite time scale that subdivides .Gregorian year. into 366 of .Gregorian day of year.
Necessity:	The granularity of the Gregorian year of days scale is .day..
with:
Definition:	the finite time scale that has granularity 1 day and that has cardinality 366 and that subdivides 'Gregorian year'
Note:	Each leap year is subdivided into 366 Gregorian day of year time points. Each common year is subdivided into 365 Gregorian day of year time points.
5.  In clause 11.1 (was 9.5.5), in the entry for 'Gregorian month of days scale', REPLACE the Definition and the first Necessity:
Definition:	the finite time scale that subdivides .Gregorian month. into 31 of .Gregorian day of month.
Necessity:	The granularity of the Gregorian month of days scale is .day..
with:
Definition:	the finite time scale that has granularity 1 day and that has cardinality 31 and that subdivides 'Gregorian month of year'
Note:	Each Gregorian month of year is subdivided into a specific number of Gregorian day of month time points.  The subdivision of February is a set of two time sequences.
6. In clause 11.2, in the entry for 'common year', after the Definition paragraph, ADD:
Necessity:	Each common year has 365 of 'Gregorian day of year'.
7. In clause 11.2, in the entry for 'leap year', after the Definition paragraph, ADD:
Necessity:	Each leap year has 366 of 'Gregorian day of year'.
8.  In clause 11.2, before the entry for Gregorian day, INSERT a new entry:
Gregorian calendar month 
Definition:	Gregorian month or Gregorian month of year
Concept Type:	concept type 

9.  In clause 11.2, at the end, ADD a new entry:
Gregorian calendar day 
Definition:	Gregorian day or Gregorian day of year or Gregorian day of month or Gregorian day of week
Concept Type:	concept type 

10.  [Note to Editor:  There is a pattern to these changes:  For all but February, insert "of '" between the number and the term that follows it, and follow the term with a closing single quote (').
10a. In clause 11.3, in the entry for January, REPLACE the Necessity that reads:
Necessity:	January has 31 Gregorian days of month.
with
Necessity:	January has 31 of 'Gregorian day of month'.
10b. In clause 11.3, in the entry for February, REPLACE the Necessities that read:
Necessity:	If the Gregorian year is a common year, then February has 28 Gregorian days of month.
Necessity:	If the Gregorian year is a leap year, then February has 29 Gregorian days of month.
with:
Necessity:	The number of 'Gregorian day of month' that February has is 28 or 29. 
Necessity:	The time point sequence that is Gregorian day of month 1 through Gregorian day of month 28 corresponds to each February that is during a common year.
Necessity:	The time point sequence that is Gregorian day of month 1 through Gregorian day of month 29 corresponds to each February that is during a leap year.
Note:	The set of these two time point sequences is how Gregorian month of days subdivides February.
10c. In clause 11.3, in the entry for March, REPLACE the Necessity that reads:
Necessity:	March has 31 Gregorian days of month.
with
Necessity:	March has 31 of 'Gregorian day of month'.
10d. In clause 11.3, in the entry for April, REPLACE the Necessity that reads:
Necessity:	April has 30 Gregorian days of month.
with
Necessity:	April has 30 of 'Gregorian day of month'.
10e. In clause 11.3, in the entry for May, REPLACE the Necessity that reads:
Necessity:	May has 31 Gregorian days of month.
with
Necessity:	May has 31 of 'Gregorian day of month'.
10f. In clause 11.3, in the entry for June, REPLACE the Necessity that reads:
Necessity:	June has 30 Gregorian days of month.
with
Necessity:	June has 30 of 'Gregorian day of month'.
10g. In clause 11.3, in the entry for July, REPLACE the Necessity that reads:
Necessity:	July has 31 Gregorian days of month.
with
Necessity:	July has 31 of 'Gregorian day of month'.
10h. In clause 11.3, in the entry for August, REPLACE the Necessity that reads:
Necessity:	August has 31 Gregorian days of month.
with
Necessity:	August has 31 of 'Gregorian day of month'.
10i. In clause 11.3, in the entry for September, REPLACE the Necessity that reads:
Necessity:	September has 30 Gregorian days of month.
with
Necessity:	September has 30 of 'Gregorian day of month'.
10j. In clause 11.3, in the entry for October, REPLACE the Necessity that reads:
Necessity:	October has 31 Gregorian days of month.
with
Necessity:	October has 31 of 'Gregorian day of month'.
10k. In clause 11.3, in the entry for November, REPLACE the Necessity that reads:
Necessity:	November has 30 Gregorian days of month.
with
Necessity:	November has 30 of 'Gregorian day of month'.
10l. In clause 11.3, in the entry for December, REPLACE the Necessity that reads:
Necessity:	December has 31 Gregorian days of month.
with
Necessity:	December has 31 of 'Gregorian day of month'.

11.  In clause 12.2, in the entry for week of days scale, REPLACE the Definition and the first Necessity:
Definition:	the finite time scale that subdivides .calendar week. into 7 of .calendar day.
Necessity:	The granularity of the week of days scale is .day..
with:
Definition:	the finite time scale that has granularity 1 day and that has cardinality 7 and that exactly subdivides 'calendar week'
Necessity:	Each calendar week has 7 of 'day of week'.

12.  In clause 13.1, in the entry for day of hours scale, REPLACE the Definition and the first Necessity:
Definition:	the finite time scale of 24 .hour of day.
Necessity:	The granularity of the day of hours scale is .hour..
with:
Definition:	the finite time scale that has granularity 1 hour and that has cardinality 24 and that exactly subdivides 'Gregorian calendar day'
Necessity:	Each calendar day has 24 of 'hour of day'.
13.  In clause 13.1, in the entry for day of minutes scale, REPLACE the Definition and the first Necessity:
Definition:	the finite time scale that subdivides each calendar day into 1440 .minute of day.
Necessity:	The granularity of the day of minutes scale is .minute..
with:
Definition:	the finite time scale that has granularity 1 minute and that has cardinality 1440 and that exactly subdivides 'Gregorian calendar day'
Necessity:	Each calendar day has 1440 of 'minute of day'.

14.  In clause 13.1, in the entry for day of seconds scale, REPLACE the Definition, the following Note and the first Necessity:
Definition:	the finite time scale that subdivides each calendar day into at most 86401 .second of day.
Note:	The second of day with index 86400 corresponds only to leap seconds. Because of leap seconds, a calendar day can have a duration of 86399, 86400, or 86401 seconds. 
Necessity:	The granularity of the day of seconds scale is .second..
with:
Definition:	the finite time scale that has granularity 1 second and that has cardinality 86400 and that exactly subdivides 'Gregorian calendar day'
Necessity:	Each calendar day has 86400 of 'second of day'.

15.  In clause 13.1, in the entry for hour of minutes scale, REPLACE the Definition and the first Necessity:
Definition:	the finite time scale that subdivides each minute of hour into 60 .minute of hour.
Necessity:	The granularity of the hour of minutes scale is .minute..
with:
Definition:	the finite time scale that has granularity 1 minute and that has cardinality 60 and that exactly subdivides 'minute of hour'
Necessity:	Each hour of day has 60 of 'minute of hour'.

16.  In clause 13.1, in the entry for minute of seconds scale, REPLACE the Definition, the following Note and the first Necessity:
Definition:	the finite time scale that subdivides each minute of day into at most 61 .second of minute.
Note:	The second of minute with index 60 corresponds only to leap seconds. Because of leap seconds, a minute of hour 59 can have a duration of 59, 60, or 61 seconds. 
Necessity:	The granularity of the minute of seconds scale is .second..
with:
Definition:	the finite time scale that has granularity 1 second and that has cardinality 60 and that exactly subdivides 'minute of hour'
Necessity:	Each minute of hour has 60 of 'second of minute'.


Disposition:	Resolved

<Down>
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Subject: Re: DTV Issue 16951 - time point subdivision -- are we there yet?
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Ed, 

I (tried to) rewrite some of the Definitions and Necessities to make them clearer.  I expect that we'll need to discuss them.   

Regarding the practice for writing Definitions and Necessities of verb concepts: I think that Definitions implicitly apply to the verb concept; there is no need to say "if x <verb> y then ....".  With Necessities, I employed the verb concept within the text of the Necessity.  For example "each x that <verb> y ...."  I think that sufficiently ties the verb concept to the rest of the Necessity. 

I have a question about figure 10.x: why is the cardinality on the 'time point kind' end of 'subdivides' 0..1 but on 'exactly subdivides' it is just '1'.    I doubt that we have any finite time scale that divides 0 time point kinds because the whole point of a finite time scale is to subdivide a time point. 
--------------------------------
Mark H. Linehan
STSM, IBM Research 



From:        Ed Barkmeyer <edbark@nist.gov> 
To:        Mark H Linehan/Watson/IBM@IBMUS, 
Cc:        "date-time-ftf@omg.org" <date-time-ftf@omg.org> 
Date:        08/17/2012 07:38 PM 
Subject:        Re: DTV Issue 16951 - time point subdivision -- are we there yet? 

--------------------------------------------------------------------------------





Mark H Linehan wrote: 
Overall, I think the design is good. 

My main comment is that I don't like Definitions and Necessities that read like CLIF axioms. We can discuss them during the next conference call. 

Yes.  If you want to propose rewordings, fine.  

It sounds like 'finite time scale exactly subdivides time point kind' is a specialization of 'finite time scale subdivides time point'. 

Of course, the Necessity makes that clear.  And the UML generalization is drawn in the revised diagram (attached).  Do you also want a Note to that effect?  The first question is:  Do we all agree that exactly subdivides is important/useful?

Minor comments: 

* 'concept type' should be styled in the glossary entry for 'time point kind' 
* We should consistently style vocabulary references in Notes. 

Fine.  I wouldn't mind styling terms in a Note if the term were just underscored in the Times Roman text, but making every term in a Note appear in 25% larger Arial (not Helvetic) teal interrupts the flow of reading.  And the purpose of a Note is to explain something to readers, not tools.

* The formatting of the "Example" captions is messed up. 

Not in Word 2010, and not in the PDF it generates.

* I don't understand this Note: "The finite time scale may subdivide all time points of a kind into the same  time point sequence or it may subdivide different time points into time point sequences of different lengths" 

I revised the wording.

* In the Definition of "time point has number of time point kind", the reference to 'finite time scale' should be to 'time point sequence' (??) 

In the Definition, there are two references that use the term 'finite time scale'.  The first is in a definite description of a specific instance of 'finite time scale'.  The second is a 'back reference' to the first, using the term 'the finite time scale', as described in Annex C.  (Mark prefers subscripting these things, and then says he doesn't like definitions that read like CLIF.)

I'm not married to any of this.  I just tried to define the verb form that the existing text used in many Necessities.  And, of course, it had the flavor of what I called 'subdivides2'.  

* The Example under "time point has number of time point kind" is not an example of that verb concept 

Fixed.  I copied the Example from above, intending to rework it, and then forgot to.

* I don't understand the Necessity "Each Gregorian year is subdivided into a the same sequence of  12 Gregorian month of year time points." 

Rewritten formally.  The Necessity follows from 'exactly'.  I think this was a Note that Word guessed the wrong caption for.  I was trying to show the difference between year of months and year of days.  One subdivision always uses the same time point sequence; the other uses different ones at different times.

* Why did you put this into a Note rather than the Definition of 'Gregorian year of days scale':  "Each leap year is subdivided into 366 Gregorian day of year time points. Each common year is subdivided into 365 Gregorian day of year time points." 

It is a Note here, because (a) it goes beyond the Definition, but (b) it shows that this is a case where the finite time scale subdivides different time points differently.  That is why this subdivision is not 'exactly subdivides'.  These two sentences are Necessities under leaip year and common year.

[Aside:  Something is wrong with the leap year, common year, etc. definitions.  A quadricentennial year is a centennial year, by definition.  I think centennial years break down into common centennial years and quadricentennial years.]

* The new glossary entries for 'Gregorian calendar month' and 'Gregorian calendar day' should be marked 'concept type'.   

Done.

And we need a new version of figure 11.3. 

Yes, and possibly others.  

* What about the 'year of weekdays scale' and the 'year of weeks scale' 

I thought we agreed to work those under a separate issue.  I added that note to the Resolution text.

-Ed 

--------------------------------
Mark H. Linehan
STSM, IBM Research 



From:        Ed Barkmeyer <edbark@nist.gov> 
To:        OMG DateTimeVoc FTF <date-time-ftf@omg.org>, 
Date:        08/16/2012 05:48 PM 
Subject:        DTV Issue 16951 - time point subdivision -- are we there yet? 

--------------------------------------------------------------------------------



All,

I offer yet another draft (9) for resolving this issue.  I think this draft finally covers the whole ground.  It addresses everything in the last two discussions.  And I hope it covers all of Mark's concerns.

When trying to implement the results of Monday's telecon, I noticed that the wording actually used in defining Gmonth time points in 11.3 (N.S.  ) for 'converts to' is 'has number of'.  So I defined it.  The definition is not equivalent to 'converts to', so we need to decide whether they need to be different.

I also made an attempt at handling the February problem.  The difficulty with the solution discussed in the telecon is that there is only one February time point.  It can have subtypes, but the subtypes are not time points -- they don't appear on any time scale.  And since they are not time points, they don't 'convert to' anything.

In implementing the change, I repaired the 'month of year' error that we noted, and a few others.

I still need to create a revised UML diagram.

I think this will need another revision, but I do think we finally understand all the issues.  

-Ed


-- 
Edward J. Barkmeyer                        Email: edbark@nist.gov
National Institute of Standards & Technology
Manufacturing Systems Integration Division
100 Bureau Drive, Stop 8263                Tel: +1 301-975-3528
Gaithersburg, MD 20899-8263                Cel: +1 240-672-5800

"The opinions expressed above do not reflect consensus of NIST, 
and have not been reviewed by any Government authority."
[attachment "DTV Issue 16951-time point subdivision-d9.docx" deleted by Mark H Linehan/Watson/IBM] 

-- 
Edward J. Barkmeyer                        Email: edbark@nist.gov
National Institute of Standards & Technology
Manufacturing Systems Integration Division
100 Bureau Drive, Stop 8263                Tel: +1 301-975-3528
Gaithersburg, MD 20899-8263                Cel: +1 240-672-5800

"The opinions expressed above do not reflect consensus of NIST, 
and have not been reviewed by any Government authority."
[attachment "DTV Issue 16951-time point subdivision-d10.docx" deleted by Mark H Linehan/Watson/IBM] 


 Date-Time Issue 16951- time point subdivision is out of place twice mhl.docx <Down>
<Down>
Disposition: Resolved
OMG Issue No:  16951
Title:	Time point subdivision is out of place twice
Source:  Ed Barkmeyer, NIST, edbark@nist.gov

Summary:
At the end of section 9.3 the fact type 'finite time scale subdivides time point' is defined and depicted in Figure 9-6.  This fact type is a commonly used property of finite time scales, and is not specific to individual time points.  That is, the finite time scale day-of-hours subdivides every day-of-month, for example.  So the text and diagram should be at the end of 9.2, where finite time scale is defined. 
Also, diagram 9-6 does not show the operations on time point and finite time scale that are associated with this fact type and shown in diagram 12-12.
Finally, diagram 12-12 (section 12.4) shows this fact type as well, but section 12.4 never uses it, and diagram 12-12 shows a <<specialization>> relationship that is never discussed anywhere in the text.  If the relationship is important, it should be discussed.  Otherwise, the subdivision association is out of place in diagram 12-12 and the "specialization" dependency should be deleted from the UML model.
Recommendation: Move the diagram and text for 'finite time scale subdivides time point' to the end of 9.2, include the operations on the diagram.  Delete the fact type from diagram 12-12, and delete the "specialization" dependency altogether.

Resolution:
The FTF agrees that the fact-type 'finite time scale subdivides time point' should be moved, along with Figure 9-6, but it depends on concepts defined in 9.3 and 9.4. It is an important concept that should have its own subsection.  This concept is used only in defining finite time scales within Calendars.  So the new section goes in clause 10 (formerly 9.5) Calendars.  
The verb concept 'finite time scale subdivides time point' is not quite the way it is used.  All of the existing usages have the form:  'finite time scale subdivides time point into number of time point kind.'  But the finite time scale determines the time point kind, so that is redundant.  Also, it is not clear whether the intent is to specify the cardinality of the finite time scale or the cardinality of the time point sequence that is the subdivision of individual time points, such as months of the year.  The text is revised to distinguish subdivides as a characteristic of finite time scales from the specification of the actual time point sequences used to subdivide individual time points.  The term exactly subdivides is used when all the time points have the same subdivision; and the special cases use the (now defined) verb 'time point has number of time point kind' that was already present in the entries for the special cases.
Note:  This clarification was not applied to the 'year of weeks' and 'year of weekdays' time scales, whose nature is addressed by a different issue.  Simply stated, the year of weeks does not subdivide a calendar year.
The concept in diagram 10.14 (formerly 12.12) . time point converts to time point sequence on time scale . is only distantly related.  The nature of the time point sequences involved is different, and the purposes are different.  The purpose of time point subdivision is to be part of the definition of finite time scales.  Diagram 10.14 (formerly 12.12) no longer shows the "specialization"; it was removed by resolution of another issue.  

Revised Text:
1.  At the end of 8.5 (was 9.3), DELETE Figure 8.18 (was 9.6) and the following text:
(Figure 8.18)
Figure 8.18: Time Scale Subdivision
finite time scale subdivides time point
Definition:	the finite time scale divides the time point into a number of time intervals that each have a duration, and the number is the cardinality of the finite time scale, and the duration is the granularity of the finite time scale
Example:	The day of hours scale subdivides the Gregorian date 3 January 2010 into 24 time intervals, each of duration "hour"

2.  Immediately before section 10.3 (was 9.5), create a new subsection numbered 10.3, and renumber the subsequent sections: 
10.3  Time Point Subdivision
The purpose of finite time scales is to provide finer-grained resolution of time intervals within the time intervals that are instances of time points with coarser granularities.  In this specification, the relationship between a finite time scale and a coarser time point is called .time point subdivision..  Many finite time scales are defined by the category of time point they subdivide and the granularity of the time points they contain.
 
Figure 10.x: Time Point Subdivision
time point kind 
Definition:	concept that is a specialization of the concept 'time point'
Concept Type:	categorization type
Example:	.Gregorian month of year. is a time point kind because it specializes  .calendar month. which itself specializes .time point.. .January. is not a time point kind because it is an instance (not a specialization) of .Gregorian month of year..
finite time scale subdivides time point kind 
Definition:	each instance1 of each time point that is an instance2 of the time point kind is an instance3 of some time point sequence that is on the finite time scale and the first time point of the time point sequence is the index origin member of the finite time scale
Note:	This verb concept describes the purpose of the finite time scale:  each time point of the finite time scale corresponds to time intervals according to their position relative to the start of a time interval that is an instance of some time point of the time point kind.  The first time point of the finite time scale corresponds to time intervals that start the larger time intervals and have a duration equal to the granularity of the finite time scale.
Necessity:	The granularity of the finite time scale is less than the duration of each time point that is an instance of the time point kind.
Note:	The time point sequence may correspond to many more time intervals than the instances of such time points.  
Note:	The same time point sequence may be the subdivision of all time points of the time point kind, or different time points of the time point kind may be subdivided into time point sequences of different lengths.  
Example:	The day of hours scale subdivides Gregorian calendar day. Every time point that is a Gregorian calendar day is subdivided  into 24 hour of day time points, and each corresponding time interval is divided into 24 time intervals, each of which is an instance of one hour of day.  
Example:	The Gregorian month of days scale subdivides month of year. Every time point that is a Gregorian month of year is subdivided  into some number of day of month time points, and the time point sequences all begin with day of month 1, but the cardinality of the time point sequence depends on which month time point is subdivided.  
time point has number of time point kind 
Definition:	each instance of the time point kind is a member of some finite time scale and some time point sequence is on the finite time scale and the first time point of the time point sequence is the index origin member of the finite time scale and the number is the cardinality of the time point sequence and the time point sequence corresponds to each instance of time point 
Note:	This verb concept describes the relationship between the finite time scale and an individual time point of the kind that the finite time scale subdivides.  That is, it completely specifies the subdividing time point sequence.
Necessity:	Each time point that has a number of some time point kind is an instance of some time point kind2 and each instance of the time point kind is a member of some finite time scale and the finite time scale subdivides the time point kind2.
Example:	Gregorian day 3 January 2010 has 24 'hour of day' time points.  The time interval corresponding to Gregorian date 3 January 2010 is implicitly subdivided into 24 time intervals, each of which is an instance of one hour of day.  But that same 24-hour time point sequence is the subdivision of every Gregorian day, and it corresponds to every time interval that is an instance of a Gregorian day.
finite time scale exactly subdivides time point kind 
General Concept:	finite time scale subdivides time point kind
Definition:	for each time point that is an instance of time point kind, the time point sequence that is the finite time scale corresponds to each time interval that is an instance of the time point 
Necessity:	Each finite time scale that exactly subdivides a time point kind is a time point sequence that corresponds to each time interval that is an instance of each time point that is an instance of the time point kind.
Necessity:	The cardinality of each finite time scale that exactly subdivides a time point sequence times the granularity of the finite time scale is the duration of each instance of each time point that is an instance of the time point kind.
Example:	The day of hours scale exactly subdivides Gregorian day of month.  Every Gregorian day of month therefore has 24 of 'hour of day', because 24 is the cardinality of the day of hours scale.

3.  In clause 11.1 (was 9.5.5), in the entry for 'Gregorian year of months scale', REPLACE the Definition and the first Necessity:
Definition:	the finite time scale that subdivides .Gregorian year. into 12 of .Gregorian month of year.
Necessity:	The granularity of the Gregorian year of months scale is .month..
with:
Definition:	the finite time scale that has granularity 1 month and that has cardinality 12 and that exactly subdivides 'Gregorian year'
Necessity:	Each Gregorian year has 12 of Gregorian month of year.
4.  In clause 11.1 (was 9.5.5), in the entry for 'Gregorian year of days scale', REPLACE the Definition and the first Necessity:
Definition:	the finite time scale that subdivides .Gregorian year. into 366 of .Gregorian day of year.
Necessity:	The granularity of the Gregorian year of days scale is .day..
with:
Definition:	the finite time scale that has granularity 1 day and that has cardinality 366 and that subdivides 'Gregorian year'
Note:	Each leap year is subdivided into 366 Gregorian day of year time points. Each common year is subdivided into 365 Gregorian day of year time points.
5.  In clause 11.1 (was 9.5.5), in the entry for 'Gregorian month of days scale', REPLACE the Definition and the first Necessity:
Definition:	the finite time scale that subdivides .Gregorian month. into 31 of .Gregorian day of month.
Necessity:	The granularity of the Gregorian month of days scale is .day..
with:
Definition:	the finite time scale that has granularity 1 day and that has cardinality 31 and that subdivides 'Gregorian month of year'
Note:	Each Gregorian month of year is subdivided into a specific number of Gregorian day of month time points.  The subdivision of February is a set of two time sequences.
6. In clause 11.2, in the entry for 'common year', after the Definition paragraph, ADD:
Necessity:	Each common year has 365 of 'Gregorian day of year'.
7. In clause 11.2, in the entry for 'leap year', after the Definition paragraph, ADD:
Necessity:	Each leap year has 366 of 'Gregorian day of year'.
8.  In clause 11.2, before the entry for Gregorian day, INSERT a new entry:
Gregorian calendar month 
Definition:	Gregorian month or Gregorian month of year
Concept Type:	concept type 

9.  In clause 11.2, at the end, ADD a new entry:
Gregorian calendar day 
Definition:	Gregorian day or Gregorian day of year or Gregorian day of month or Gregorian day of week
Concept Type:	concept type 

10.  [Note to Editor:  There is a pattern to these changes:  For all but February, insert "of '" between the number and the term that follows it, and follow the term with a closing single quote (').
10a. In clause 11.3, in the entry for January, REPLACE the Necessity that reads:
Necessity:	January has 31 Gregorian days of month.
with
Necessity:	January has 31 of 'Gregorian day of month'.
10b. In clause 11.3, in the entry for February, REPLACE the Necessities that read:
Necessity:	If the Gregorian year is a common year, then February has 28 Gregorian days of month.
Necessity:	If the Gregorian year is a leap year, then February has 29 Gregorian days of month.
with:
Necessity:	The number of 'Gregorian day of month' that February has is 28 or 29.
Necessity:	The time point sequence that is Gregorian day of month 1 through Gregorian day of month 28 corresponds to each February that is during a common year.
Necessity:	The time point sequence that is Gregorian day of month 1 through Gregorian day of month 29 corresponds to each February that is during a leap year.
Note:	The set of these two time point sequences is how Gregorian month of days subdivides February.
10c. In clause 11.3, in the entry for March, REPLACE the Necessity that reads:
Necessity:	March has 31 Gregorian days of month.
with
Necessity:	March has 31 of 'Gregorian day of month'.
10d. In clause 11.3, in the entry for April, REPLACE the Necessity that reads:
Necessity:	April has 30 Gregorian days of month.
with
Necessity:	April has 30 of 'Gregorian day of month'.
10e. In clause 11.3, in the entry for May, REPLACE the Necessity that reads:
Necessity:	May has 31 Gregorian days of month.
with
Necessity:	May has 31 of 'Gregorian day of month'.
10f. In clause 11.3, in the entry for June, REPLACE the Necessity that reads:
Necessity:	June has 30 Gregorian days of month.
with
Necessity:	June has 30 of 'Gregorian day of month'.
10g. In clause 11.3, in the entry for July, REPLACE the Necessity that reads:
Necessity:	July has 31 Gregorian days of month.
with
Necessity:	July has 31 of 'Gregorian day of month'.
10h. In clause 11.3, in the entry for August, REPLACE the Necessity that reads:
Necessity:	August has 31 Gregorian days of month.
with
Necessity:	August has 31 of 'Gregorian day of month'.
10i. In clause 11.3, in the entry for September, REPLACE the Necessity that reads:
Necessity:	September has 30 Gregorian days of month.
with
Necessity:	September has 30 of 'Gregorian day of month'.
10j. In clause 11.3, in the entry for October, REPLACE the Necessity that reads:
Necessity:	October has 31 Gregorian days of month.
with
Necessity:	October has 31 of 'Gregorian day of month'.
10k. In clause 11.3, in the entry for November, REPLACE the Necessity that reads:
Necessity:	November has 30 Gregorian days of month.
with
Necessity:	November has 30 of 'Gregorian day of month'.
10l. In clause 11.3, in the entry for December, REPLACE the Necessity that reads:
Necessity:	December has 31 Gregorian days of month.
with
Necessity:	December has 31 of 'Gregorian day of month'.

11.  In clause 12.2, in the entry for week of days scale, REPLACE the Definition and the first Necessity:
Definition:	the finite time scale that subdivides .calendar week. into 7 of .calendar day.
Necessity:	The granularity of the week of days scale is .day..
with:
Definition:	the finite time scale that has granularity 1 day and that has cardinality 7 and that exactly subdivides 'calendar week'
Necessity:	Each calendar week has 7 of 'day of week'.

12.  In clause 13.1, in the entry for day of hours scale, REPLACE the Definition and the first Necessity:
Definition:	the finite time scale of 24 .hour of day.
Necessity:	The granularity of the day of hours scale is .hour..
with:
Definition:	the finite time scale that has granularity 1 hour and that has cardinality 24 and that exactly subdivides 'Gregorian calendar day'
Necessity:	Each calendar day has 24 of 'hour of day'.
13.  In clause 13.1, in the entry for day of minutes scale, REPLACE the Definition and the first Necessity:
Definition:	the finite time scale that subdivides each calendar day into 1440 .minute of day.
Necessity:	The granularity of the day of minutes scale is .minute..
with:
Definition:	the finite time scale that has granularity 1 minute and that has cardinality 1440 and that exactly subdivides 'Gregorian calendar day'
Necessity:	Each calendar day has 1440 of 'minute of day'.

14.  In clause 13.1, in the entry for day of seconds scale, REPLACE the Definition, the following Note and the first Necessity:
Definition:	the finite time scale that subdivides each calendar day into at most 86401 .second of day.
Note:	The second of day with index 86400 corresponds only to leap seconds. Because of leap seconds, a calendar day can have a duration of 86399, 86400, or 86401 seconds. 
Necessity:	The granularity of the day of seconds scale is .second..
with:
Definition:	the finite time scale that has granularity 1 second and that has cardinality 86400 and that exactly subdivides 'Gregorian calendar day'
Necessity:	Each calendar day has 86400 of 'second of day'.

15.  In clause 13.1, in the entry for hour of minutes scale, REPLACE the Definition and the first Necessity:
Definition:	the finite time scale that subdivides each minute of hour into 60 .minute of hour.
Necessity:	The granularity of the hour of minutes scale is .minute..
with:
Definition:	the finite time scale that has granularity 1 minute and that has cardinality 60 and that exactly subdivides 'minute of hour'
Necessity:	Each hour of day has 60 of 'minute of hour'.

16.  In clause 13.1, in the entry for minute of seconds scale, REPLACE the Definition, the following Note and the first Necessity:
Definition:	the finite time scale that subdivides each minute of day into at most 61 .second of minute.
Note:	The second of minute with index 60 corresponds only to leap seconds. Because of leap seconds, a minute of hour 59 can have a duration of 59, 60, or 61 seconds. 
Necessity:	The granularity of the minute of seconds scale is .second..
with:
Definition:	the finite time scale that has granularity 1 second and that has cardinality 60 and that exactly subdivides 'minute of hour'
Necessity:	Each minute of hour has 60 of 'second of minute'.


Disposition:	Resolved

Date: Mon, 20 Aug 2012 12:20:08 -0400
From: Ed Barkmeyer <edbark@nist.gov>
Reply-To: <edbark@nist.gov>
Organization: NIST
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To: Mark H Linehan <mlinehan@us.ibm.com>
CC: "date-time-ftf@omg.org" <date-time-ftf@omg.org>
Subject: Re: DTV Issue 16951 - time point subdivision -- are we there yet?
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Mark H Linehan wrote:
Ed,


I (tried to) rewrite some of the Definitions and Necessities to make them clearer.  I expect that we'll need to discuss them.  


I haven't looked at them yet.


Regarding the practice for writing Definitions and Necessities of verb concepts: I think that Definitions implicitly apply to the verb concept; there is no need to say "if x <verb> y then ....".  With Necessities, I employed the verb concept within the text of the Necessity.  For example "each x that <verb> y ...."  I think that sufficiently ties the verb concept to the rest of the Necessity.


I agree completely with this.


I have a question about figure 10.x: why is the cardinality on the 'time point kind' end of 'subdivides' 0..1 but on 'exactly subdivides' it is just '1'.    I doubt that we have any finite time scale that divides 0 time point kinds because the whole point of a finite time scale is to subdivide a time point.


That is exactly backwards.  Every finite time scale subdivides 1 time point kind, only some exactly subdivide.


-Ed


--------------------------------
Mark H. Linehan
STSM, IBM Research




From:        Ed Barkmeyer <edbark@nist.gov>
To:        Mark H Linehan/Watson/IBM@IBMUS,
Cc:        "date-time-ftf@omg.org" <date-time-ftf@omg.org>
Date:        08/17/2012 07:38 PM
Subject:        Re: DTV Issue 16951 - time point subdivision -- are we there yet?
------------------------------------------------------------------------






Mark H Linehan wrote:
Overall, I think the design is good.


My main comment is that I don't like Definitions and Necessities that read like CLIF axioms. We can discuss them during the next conference call.


Yes.  If you want to propose rewordings, fine.  


It sounds like 'finite time scale exactly subdivides time point kind' is a specialization of 'finite time scale subdivides time point'.


Of course, the Necessity makes that clear.  And the UML generalization is drawn in the revised diagram (attached).  Do you also want a Note to that effect?  The first question is:  Do we all agree that exactly subdivides is important/useful?


Minor comments:


* 'concept type' should be styled in the glossary entry for 'time point kind'
* We should consistently style vocabulary references in Notes.


Fine.  I wouldn't mind styling terms in a Note if the term were just underscored in the Times Roman text, but making every term in a Note appear in 25% larger Arial (not Helvetic) teal interrupts the flow of reading.  And the purpose of a Note is to explain something to readers, not tools.


* The formatting of the "Example" captions is messed up.


Not in Word 2010, and not in the PDF it generates.


* I don't understand this Note: "The finite time scale may subdivide all time points of a kind into the same  time point sequence or it may subdivide different time points into time point sequences of different lengths"


I revised the wording.


* In the Definition of "time point has number of time point kind", the reference to 'finite time scale' should be to 'time point sequence' (??)


In the Definition, there are two references that use the term 'finite time scale'.  The first is in a definite description of a specific instance of 'finite time scale'.  The second is a 'back reference' to the first, using the term 'the finite time scale', as described in Annex C.  (Mark prefers subscripting these things, and then says he doesn't like definitions that read like CLIF.)


I'm not married to any of this.  I just tried to define the verb form that the existing text used in many Necessities.  And, of course, it had the flavor of what I called 'subdivides2'.  


* The Example under "time point has number of time point kind" is not an example of that verb concept


Fixed.  I copied the Example from above, intending to rework it, and then forgot to.


* I don't understand the Necessity "Each Gregorian year is subdivided into a the same sequence of  12 Gregorian month of year time points."


Rewritten formally.  The Necessity follows from 'exactly'.  I think this was a Note that Word guessed the wrong caption for.  I was trying to show the difference between year of months and year of days.  One subdivision always uses the same time point sequence; the other uses different ones at different times.


* Why did you put this into a Note rather than the Definition of 'Gregorian year of days scale':  "Each _leap year_ is subdivided into 366 _Gregorian day of year_ time points. Each _common year_ is subdivided into 365 _Gregorian day of year_ time points."


It is a Note here, because (a) it goes beyond the Definition, but (b) it shows that this is a case where the finite time scale subdivides different time points differently.  That is why this subdivision is not 'exactly subdivides'.  These two sentences are Necessities under leaip year and common year.


[Aside:  Something is wrong with the leap year, common year, etc. definitions.  A quadricentennial year is a centennial year, by definition.  I think centennial years break down into common centennial years and quadricentennial years.]


* The new glossary entries for 'Gregorian calendar month' and 'Gregorian calendar day' should be marked 'concept type'.  


Done.


And we need a new version of figure 11.3.


Yes, and possibly others.  


* What about the 'year of weekdays scale' and the 'year of weeks scale'


I thought we agreed to work those under a separate issue.  I added that note to the Resolution text.


-Ed


--------------------------------
Mark H. Linehan
STSM, IBM Research




From:        Ed Barkmeyer _<edbark@nist.gov>_ <mailto:edbark@nist.gov>
To:        OMG DateTimeVoc FTF _<date-time-ftf@omg.org>_ <mailto:date-time-ftf@omg.org>,
Date:        08/16/2012 05:48 PM
Subject:        DTV Issue 16951 - time point subdivision -- are we there yet?
------------------------------------------------------------------------




All,


I offer yet another draft (9) for resolving this issue.  I think this draft finally covers the whole ground.  It addresses everything in the last two discussions.  And I hope it covers all of Mark's concerns.


When trying to implement the results of Monday's telecon, I noticed that the wording actually used in defining Gmonth time points in 11.3 (N.S.  ) for 'converts to' is 'has number of'.  So I defined it.  The definition is not equivalent to 'converts to', so we need to decide whether they need to be different.


I also made an attempt at handling the February problem.  The difficulty with the solution discussed in the telecon is that there is only one February time point.  It can have subtypes, but the subtypes are not time points -- they don't appear on any time scale.  And since they are not time points, they don't 'convert to' anything.


In implementing the change, I repaired the 'month of year' error that we noted, and a few others.


I still need to create a revised UML diagram.


I think this will need another revision, but I do think we finally understand all the issues.  


-Ed



-- 
Edward J. Barkmeyer                        Email: _edbark@nist.gov_ <mailto:edbark@nist.gov>
National Institute of Standards & Technology
Manufacturing Systems Integration Division
100 Bureau Drive, Stop 8263                Tel: +1 301-975-3528
Gaithersburg, MD 20899-8263                Cel: +1 240-672-5800


"The opinions expressed above do not reflect consensus of NIST,
and have not been reviewed by any Government authority."
[attachment "DTV Issue 16951-time point subdivision-d9.docx" deleted by Mark H Linehan/Watson/IBM]


-- 
Edward J. Barkmeyer                        Email: _edbark@nist.gov_ <mailto:edbark@nist.gov>
National Institute of Standards & Technology
Manufacturing Systems Integration Division
100 Bureau Drive, Stop 8263                Tel: +1 301-975-3528
Gaithersburg, MD 20899-8263                Cel: +1 240-672-5800


"The opinions expressed above do not reflect consensus of NIST,
and have not been reviewed by any Government authority."
[attachment "DTV Issue 16951-time point subdivision-d10.docx" deleted by Mark H Linehan/Watson/IBM]


-- 
Edward J. Barkmeyer                        Email: edbark@nist.gov
National Institute of Standards & Technology
Manufacturing Systems Integration Division
100 Bureau Drive, Stop 8263                Tel: +1 301-975-3528
Gaithersburg, MD 20899-8263                Cel: +1 240-672-5800


"The opinions expressed above do not reflect consensus of NIST, and have not been reviewed by any Government authority."
To: date-time-ftf@omg.org
Subject: Date-Time Issue 16951 - Time point subdivision is out of place twice
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Date: Wed, 5 Sep 2012 09:27:49 -0400
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I think we're almost done on this one.  Ed, it might speed things up if you could review the highlighted parts offline. 

--------------------------------
Mark H. Linehan
STSM, IBM Research 

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Subject: Date-Time Issue 16951 - Time point subdivision is out of place twice
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Date: Wed, 5 Sep 2012 09:27:49 -0400
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I think we're almost done on this one.  Ed, it might speed things up if you could review the highlighted parts offline. 

--------------------------------
Mark H. Linehan
STSM, IBM Research 

 Date-Time Issue 16951- time point subdivision is out of place twice1.docx <Down>
<Down>
<Down>
Disposition: Resolved
OMG Issue No:  16951
Title:	Time point subdivision is out of place twice
Source:  Ed Barkmeyer, NIST, edbark@nist.gov

Summary:
At the end of section 9.3 the fact type 'finite time scale subdivides time point' is defined and depicted in Figure 9-6.  This fact type is a commonly used property of finite time scales, and is not specific to individual time points.  That is, the finite time scale day-of-hours subdivides every day-of-month, for example.  So the text and diagram should be at the end of 9.2, where finite time scale is defined. 
Also, diagram 9-6 does not show the operations on time point and finite time scale that are associated with this fact type and shown in diagram 12-12.
Finally, diagram 12-12 (section 12.4) shows this fact type as well, but section 12.4 never uses it, and diagram 12-12 shows a <<specialization>> relationship that is never discussed anywhere in the text.  If the relationship is important, it should be discussed.  Otherwise, the subdivision association is out of place in diagram 12-12 and the "specialization" dependency should be deleted from the UML model.
Recommendation: Move the diagram and text for 'finite time scale subdivides time point' to the end of 9.2, include the operations on the diagram.  Delete the fact type from diagram 12-12, and delete the "specialization" dependency altogether.

Resolution:
The FTF agrees that the fact-type 'finite time scale subdivides time point' should be moved, along with Figure 9-6, but it depends on concepts defined in 9.3 and 9.4. It is an important concept that should have its own subsection.  This concept is used only in defining finite time scales within Calendars.  So the new section goes in clause 10 (formerly 9.5) Calendars.  
The verb concept 'finite time scale subdivides time point' is not quite the way it is used.  All of the existing usages have the form:  'finite time scale subdivides time point into number of time point kind.'  But the finite time scale determines the time point kind, so that is redundant.  Also, it is not clear whether the intent is to specify the cardinality of the finite time scale or the cardinality of the time point sequence that is the subdivision of individual time points, such as months of the year.  The text is revised to clarify that.  distinguish subdivides as a characteristic of finite time scales from the specification of the actual time point sequences used to subdivide individual time points.  The term exactly subdivides is used when all the time points have the same subdivision; and the special cases use the (now defined) verb 'time point has number of time point kind' that was already present in the entries for the special cases.
Note:  This clarification was not applied to the 'year of weeks' and 'year of weekdays' time scales, whose nature is addressed by a different issue.  Simply stated, the year of weeks does not subdivide a calendar year.
The concept in diagram 10.14 (formerly 12.12) . time point converts to time point sequence on time scale . is only distantly related.  The nature of the time point sequences involved is different, and the purposes are different.  The purpose of time point subdivision is to be part of the definition of finite time scales.  Diagram 10.14 (formerly 12.12) no longer shows the "specialization"; it was removed by resolution of another issue.  

Revised Text:
1.  At the end of 8.5 (was 9.3), DELETE Figure 8.18 (was 9.6) and the following text:
(Figure 8.18)
Figure 8.18: Time Scale Subdivision
finite time scale subdivides time point
Definition:	the finite time scale divides the time point into a number of time intervals that each have a duration, and the number is the cardinality of the finite time scale, and the duration is the granularity of the finite time scale
Example:	The day of hours scale subdivides the Gregorian date 3 January 2010 into 24 time intervals, each of duration "hour"

2.  Immediately before section 10.3 (was 9.5), create a new subsection numbered 10.3, and renumber the subsequent sections: 
10.3  Time Point Subdivision
The purpose of finite time scales is to provide finer-grained resolution of time intervals within the time intervals that are instances of time points with coarser granularities.  In this specification, the relationship between a finite time scale and a coarser time point is called .time point subdivision..  Many finite time scales are defined by the category of time point they subdivide and the granularity of the time points they contain.
 
Figure 10.x: Time Point Subdivision
time point kind 
Definition:	concept that is a specialization of the concept 'time point'
Concept Type:	categorization type
Example:	.Gregorian month of year. is a time point kind because it specializes  .calendar month. which itself specializes .time point.. .January. is not a time point kind because it is an instance (not a specialization) of .Gregorian month of year..
finite time scale subdivides time point kind 
Definition:	for each time point that is an instance of time point kind, there is a set of time point sequences  that are on the finite time scale, and
  the first time point of each time point sequence that is in the set is the index origin member of the finite time scale, and
  each time interval that is an instance of the time point is an instance of some time point sequence that is in the set
Definition:	each instance of each time point that is an instance of the time point kind is an instance of some time point sequence that is on the finite time scale, and the first time point of the time point sequence is the index origin member of the finite time scale 
Note:	This verb concept describes the purpose of the finite time scale:  each time point of the finite time scale corresponds to time intervals according to their position relative to the start of a time interval that is an instance of some time point of the time point kind.  The first time point of the finite time scale corresponds to time intervals that start the larger time intervals and have a  duration equal to the granularity of the finite time scale.
Necessity:	For most time point subdivisions, the "set of time point sequences" has exactly one member . one time point sequence corresponds to all instances of the time point.  The sole exception is the time point February.
Necessity:	The granularity of each finite time scale is less than the granularity of each time point that is an instance of the time point kind that the finite time scale subdivides. 
Necessity:	The granularity of each time point kind that is subdivided by a finite time scale is greater than the granularity of the finite time scale.
Note:	The time point sequence may correspond to many more time intervals than the instances of such time points.  
Note:	The finite time scale may subdivide all time points of a kind into the same  time point sequence or it may subdivide different time points The same  time point sequence may be the subdivision of all time points the time point kind, or different time points may be subdivided into time point sequences of different lengths.  
Note:Example:	The day of hours scale subdivides Gregorian calendar day. Every time point that is a Gregorian calendar day is subdivided  into 24 hour of day time points, and each corresponding time interval is divided into 24 time intervals, each of which is an instance of one hour- of- day.  
Note:	A time point kind may be subdivided by finite time scales of different cardinalities.
Example:	The Gregorian month of days scale subdivides month of year. Every time point that is a Gregorian month of year is subdivided  into some number of day of month time points, and the time point sequences all begin with day of month 1, but the length cardinality of the time point sequence depends on which month time point is subdivided.  
time point has number of time point kind  
Note:	there is a time point sequence that is on the finite time scale that each instance of the time point kind is a member of, and
  the first time point of the time point sequence is the index origin member of the finite time scale, and
  the cardinality of the time point sequence is number, and
  the time point sequence corresponds to each time interval that is an instance of time point
Definition:	each instance of the time point kind is a member of some finite time scale and some time point sequence is on the finite time scale and the first time point of the time point sequence is the index origin member of the finite time scale and the number is the cardinality of the time point sequence and the time point sequence corresponds to each instance of time point 
Note:	This verb concept describes the relationship between the finite time scale and an individual time point of the kind that the finite time scale subdivides.  That is, it completely specifies the subdividing time point sequence.
Example:	If a time point has some number of time point kind1, the finite time scale that each instance of time point kind1 is a member of subdivides the time point kind2 that the time point is an instance of.
Necessity:	Each time point that has a number of some time point kind is an instance of some time point kind2 and each instance of the time point kind is a member of some finite time scale and the finite time scale subdivides the time point kind2.
Example:	Gregorian day 3 January 2010 is subdivided by the day of hours scale intohas 24 'hour of day' time points.  The time interval corresponding to Gregorian date 3 January 2010 is implicitly subdivided into 24 time intervals, each of which is an instance of one hour- of- day.  But that same 24-hour time point sequence is the subdivision of every Gregorian day, and it corresponds to every time interval that is an instance of a Gregorian day time interval.
finite time scale exactly subdivides time point kind   
General Concept:	finite time scale subdivides time point kind  
Definition:	the finite time scale is a time point sequence that corresponds to each time interval that is an instance of each time point that is an instance of the time point kind
Necessity:	for each time point that is an instance of time point kind, the time point sequence that is the finite time scale corresponds to each time interval that is an instance of the time point 
Necessity:	Each finite time scale that exactly subdivides a time point kind subdivides the time point kind. 
Necessity:	If a finite time scale exactly subdivides time point kind1, and each time point of the finite time scale is an instance of time point kind2, then the number of time point kind2 that each time point that is an instance of time point kind1 has  is the cardinality of the finite time scale.
Necessity:	The cardinality of each finite time scale that exactly subdivides a time point kind times the granularity of the finite time scale equals the duration of each instance of each time point that is an instance of the time point kind.
Example:	The day of hours scale exactly subdivides Gregorian day of month.  Every Gregorian day of month therefore has 24 of 'hour of day', because 24 is the cardinality of the 'day of hours scale'.

3.  In clause 11.1 (was 9.5.5), in the entry for 'Gregorian year of months scale', REPLACE the Definition and the first Necessity:
Definition:	the finite time scale that subdivides .Gregorian year. into 12 of .Gregorian month of year.
Necessity:	The granularity of the Gregorian year of months scale is .month..
with:
Definition:	the finite time scale that has granularity 1 month and that has cardinality 12 and that exactly subdivides 'Gregorian year'
Necessity:	Each Gregorian year is subdivided into a the same sequence of  has 12 of Gregorian month of year time points.
4.  In clause 11.1 (was 9.5.5), in the entry for 'Gregorian year of days scale', REPLACE the Definition and the first Necessity:
Definition:	the finite time scale that subdivides .Gregorian year. into 366 of .Gregorian day of year.
Necessity:	The granularity of the Gregorian year of days scale is .day..
with:
Definition:	the finite time scale that has granularity 1 day and that has cardinality 366 and that subdivides 'Gregorian year'
Note:	Each leap year is subdivided into 366 Gregorian day of year time points. Each common year is subdivided into 365 Gregorian day of year time points.
5.  In clause 11.1 (was 9.5.5), in the entry for 'Gregorian month of days scale', REPLACE the Definition and the first Necessity:
Definition:	the finite time scale that subdivides .Gregorian month. into 31 of .Gregorian day of month.
Necessity:	The granularity of the Gregorian month of days scale is .day..
with:
Definition:	the finite time scale that has granularity 1 day and that has cardinality 31 and that subdivides 'Gregorian month of year'
Note:	Each Gregorian month of year is subdivided into a specific number of Gregorian day of month time points.  The subdivision of February is a set of two time sequences.
6. In clause 11.2, in the entry for 'common year', after the Definition paragraph, ADD:
Necessity:	Each common year has 365 of 'Gregorian day of year'.
7. In clause 11.2, in the entry for 'leap year', after the Definition paragraph, ADD:
Necessity:	Each leap year has 366 of 'Gregorian day of year'.
8.  In clause 11.2, before the entry for Gregorian day, INSERT a new entry:
Gregorian calendar month 
Definition:	Gregorian month or Gregorian month of year
Concept Type:	concept type 

9.  In clause 11.2, at the end, ADD a new entry:
Gregorian calendar day 
Definition:	Gregorian day or Gregorian day of year or Gregorian day of month or Gregorian day of week
Concept Type:	concept type 

10.  [Note to Editor:  There is a pattern to these changes:  For all but February, insert "of '" between the number and the term that follows it, and follow the term with a closing single quote (').
10a. In clause 11.3, in the entry for January, REPLACE the Necessity that reads:
Necessity:	January has 31 Gregorian days of month.
with
Necessity:	January has 31 of 'Gregorian day of month'.
10b. In clause 11.3, in the entry for February, REPLACE the Necessities that read:
Necessity:	If the Gregorian year is a common year, then February has 28 Gregorian days of month.
Necessity:	If the Gregorian year is a leap year, then February has 29 Gregorian days of month.
with:
Necessity:	The number of 'Gregorian day of month' that February has is 28 or 29. 
Necessity:	The time point sequence that is Gregorian day of month 1 through Gregorian day of month 28 corresponds to each February that is during a common year.
Necessity:	The time point sequence that is Gregorian day of month 1 through Gregorian day of month 29 corresponds to each February that is during a leap year.
Note:	The set of these two time point sequences is how Gregorian month of days subdivides February.
10c. In clause 11.3, in the entry for March, REPLACE the Necessity that reads:
Necessity:	March has 31 Gregorian days of month.
with
Necessity:	March has 31 of 'Gregorian day of month'.
10d. In clause 11.3, in the entry for April, REPLACE the Necessity that reads:
Necessity:	April has 30 Gregorian days of month.
with
Necessity:	April has 30 of 'Gregorian day of month'.
10e. In clause 11.3, in the entry for May, REPLACE the Necessity that reads:
Necessity:	May has 31 Gregorian days of month.
with
Necessity:	May has 31 of 'Gregorian day of month'.
10f. In clause 11.3, in the entry for June, REPLACE the Necessity that reads:
Necessity:	June has 30 Gregorian days of month.
with
Necessity:	June has 30 of 'Gregorian day of month'.
10g. In clause 11.3, in the entry for July, REPLACE the Necessity that reads:
Necessity:	July has 31 Gregorian days of month.
with
Necessity:	July has 31 of 'Gregorian day of month'.
10h. In clause 11.3, in the entry for August, REPLACE the Necessity that reads:
Necessity:	August has 31 Gregorian days of month.
with
Necessity:	August has 31 of 'Gregorian day of month'.
10i. In clause 11.3, in the entry for September, REPLACE the Necessity that reads:
Necessity:	September has 30 Gregorian days of month.
with
Necessity:	September has 30 of 'Gregorian day of month'.
10j. In clause 11.3, in the entry for October, REPLACE the Necessity that reads:
Necessity:	October has 31 Gregorian days of month.
with
Necessity:	October has 31 of 'Gregorian day of month'.
10k. In clause 11.3, in the entry for November, REPLACE the Necessity that reads:
Necessity:	November has 30 Gregorian days of month.
with
Necessity:	November has 30 of 'Gregorian day of month'.
10l. In clause 11.3, in the entry for December, REPLACE the Necessity that reads:
Necessity:	December has 31 Gregorian days of month.
with
Necessity:	December has 31 of 'Gregorian day of month'.

11.  In clause 12.2, in the entry for week of days scale, REPLACE the Definition and the first Necessity:
Definition:	the finite time scale that subdivides .calendar week. into 7 of .calendar day.
Necessity:	The granularity of the week of days scale is .day..
with:
Definition:	the finite time scale that has granularity 1 day and that has cardinality 7 and that exactly subdivides 'calendar week'
Necessity:	Each calendar week has 7 of 'day of week'.

12.  In clause 13.1, in the entry for day of hours scale, REPLACE the Definition and the first Necessity:
Definition:	the finite time scale of 24 .hour of day.
Necessity:	The granularity of the day of hours scale is .hour..
with:
Definition:	the finite time scale that has granularity 1 hour and that has cardinality 24 and that exactly subdivides 'Gregorian calendar day'
Necessity:	Each calendar day has 24 of 'hour of day'.
13.  In clause 13.1, in the entry for day of minutes scale, REPLACE the Definition and the first Necessity:
Definition:	the finite time scale that subdivides each calendar day into 1440 .minute of day.
Necessity:	The granularity of the day of minutes scale is .minute..
with:
Definition:	the finite time scale that has granularity 1 minute and that has cardinality 1440 and that exactly subdivides 'Gregorian calendar day'
Necessity:	Each calendar day has 1440 of 'minute of day'.

14.  In clause 13.1, in the entry for day of seconds scale, REPLACE the Definition, the following Note and the first Necessity:
Definition:	the finite time scale that subdivides each calendar day into at most 86401 .second of day.
Note:	The second of day with index 86400 corresponds only to leap seconds. Because of leap seconds, a calendar day can have a duration of 86399, 86400, or 86401 seconds. 
Necessity:	The granularity of the day of seconds scale is .second..
with:
Definition:	the finite time scale that has granularity 1 second and that has cardinality 86400 and that exactly subdivides 'Gregorian calendar day'
Necessity:	Each calendar day has 86400 of 'second of day'.

15.  In clause 13.1, in the entry for hour of minutes scale, REPLACE the Definition and the first Necessity:
Definition:	the finite time scale that subdivides each minute of hour into 60 .minute of hour.
Necessity:	The granularity of the hour of minutes scale is .minute..
with:
Definition:	the finite time scale that has granularity 1 minute and that has cardinality 60 and that exactly subdivides 'minute of hour'
Necessity:	Each hour of day has 60 of 'minute of hour'.

16.  In clause 13.1, in the entry for minute of seconds scale, REPLACE the Definition, the following Note and the first Necessity:
Definition:	the finite time scale that subdivides each minute of day into at most 61 .second of minute.
Note:	The second of minute with index 60 corresponds only to leap seconds. Because of leap seconds, a minute of hour 59 can have a duration of 59, 60, or 61 seconds. 
Necessity:	The granularity of the minute of seconds scale is .second..
with:
Definition:	the finite time scale that has granularity 1 second and that has cardinality 60 and that exactly subdivides 'minute of hour'
Necessity:	Each minute of hour has 60 of 'second of minute'.


Disposition:	Resolved