Issue 17232: DTV time-of-day time point definitions are inaccurate (date-time-ftf) Source: NIST (Mr. Edward J. Barkmeyer, edbark(at)nist.gov) Nature: Uncategorized Issue Severity: Summary: In DTV Clause 9.5.2, all the time-of-day time point definitions are similar. For example, it defines 'hour of day' as: time point that is on the day of hours scale and that is identified by the number of elapsed full hours since midnight on a given calendar day But each 'hour of day' is a category of time intervals. The time point is "identified by" its index. The "number of elapsed full hours" is how the index and the time point relate to the corresponding time intervals. The definition should read something more like: _time point_ that is on the _day of hours_ scale and that /corresponds to/ each _time interval_ that has duration 1 hour and that starts a calendar day, if the index of the time point is 0, or that has duration 1 hour and that is met by a time interval that starts a calendar day and that has duration n hours, where n is the index of the time point and is not 0. The other definitions should be similar. Similarly, 'midnight' appears to be the time point that corresponds to each time interval that has duration 1 second and that starts a calendar day. It is nominally an event that occurs exactly 12 hours before a reference "noon" -- a zenith of the sun. Resolution: Revised Text: Actions taken: March 13, 2012: received issue Discussion: End of Annotations:===== m: Ed Barkmeyer To: issues@omg.org Subject: DTV time-of-day time point definitions are inaccurate Specification: Date Time Vocabulary Version: beta-1 Title: time-of-day time point definitions are inaccurate Source: Ed Barkmeyer, NIST, edbark@nist.gov Summary: In DTV Clause 9.5.2, all the time-of-day time point definitions are similar. For example, it defines 'hour of day' as: time point that is on the day of hours scale and that is identified by the number of elapsed full hours since midnight on a given calendar day But each 'hour of day' is a category of time intervals. The time point is "identified by" its index. The "number of elapsed full hours" is how the index and the time point relate to the corresponding time intervals. The definition should read something more like: _time point_ that is on the _day of hours_ scale and that /corresponds to/ each _time interval_ that has duration 1 hour and that starts a calendar day, if the index of the time point is 0, or that has duration 1 hour and that is met by a time interval that starts a calendar day and that has duration n hours, where n is the index of the time point and is not 0. The other definitions should be similar. Similarly, 'midnight' appears to be the time point that corresponds to each time interval that has duration 1 second and that starts a calendar day. It is nominally an event that occurs exactly 12 hours before a reference "noon" -- a zenith of the sun. To: date-time-ftf@omg.org Subject: issue 17232 -- Description of time point conversion is confused X-KeepSent: 43618663:6F4A1A2B-852579DB:004DEB1C; type=4; name=$KeepSent X-Mailer: Lotus Notes Release 8.5.1FP5 SHF29 November 12, 2010 From: Mark H Linehan Date: Mon, 9 Apr 2012 10:10:21 -0400 X-MIMETrack: Serialize by Router on D01MC604/01/M/IBM(Release 8.5.3 ZX853HP5|January 12, 2012) at 04/09/2012 10:10:21 X-Content-Scanned: Fidelis XPS MAILER x-cbid: 12040914-1976-0000-0000-00000C2F1EEA Here's a start on this one. I have only written the "Resolution" section. I'd like to discuss that before I take the time to draft the revised text. -------------------------------- Mark H. Linehan STSM, Model Driven Business Transformation IBM Research Date-Time Issue 17227 - Description of time point conversion is confused.doc Disposition: ??? OMG Issue No: 17227 Title: Description of time point conversion is confused Source: Ed Barkmeyer, edbark@nist.gov, NIST Summary: Clause 12.4 contains the following: "The concept time point converts to time period on time scale enables conversion of a time point on some time scale1, to a time period on the given time scale. The target time scale always is finer, meaning that it has a granularity that is less than or equal to the granularity of time scale1. This means that time point is equivalent to a time period on time scale2. For example, the Gregorian month that is indicated by January (on the Gregorian year of months scale) is the time period from Gregorian day of year 1 through Gregorian day of year 31 on the Gregorian year of days scale." In all of this text, the term 'time period' should probably be replaced by 'time point sequence'. Clause 12.4 then contains this entry: "time point converts to time period on time scale Definition: time point converts to a time point sequence on the time scale and the time period instantiates the time point sequence" The verb concept 'time point converts to time point sequence' appears in diagram 12-12, but is not defined anywhere, and 'time point converts to time period on time scale' does not appear on the diagram. So the obvious interpretation is that 'time period' should be replaced by 'time point sequence' in the verb concept entry. But then the definition is circular. Resolution: The existing verb concept entry is correct, but it references another verb concept that is currently specified only in several specializations. Clarify the relationship among these by defining the general case of 'time point converts to time point sequence on time scale'. Also for clarity, add 'time point converts to time set on time scale'. Include these verb concepts in figure 12-2. Add "General Concept" captions to each specialization of these verb concepts to relate the specializations to the general concepts. Revised Text: Disposition: ???