DTV12 — Different 'time period' concept in Annex C

Specification: DTV

Version: 1.1

Title: Different 'time period' concept in Annex C

Source: Ed Barkmeyer, NIST, edbark(at)nist.gov

Summary:

In the Date Time Vocabulary v1.1 specification, Annex C contains the following terminological entries:

fixed period

Definition: time period that cannot be changed

...

variable period

Definition: time period that can be rescheduled

In DTV clause 8.7, a time period is defined to be: time interval that instantiates some time point sequence

No time interval can ever "be changed" , at least not in the sense of "modified". And similarly, time intervals are unlikely to be "rescheduled". One cannot alter the time interval designated July 25 into some other time interval, nor can one meaningfully reschedule it.

The intent here seems to be that some kind of schedule entry can be changed or an event can be rescheduled, so that the entry refers to a different time interval. Therefore, the term 'time period', as used in Annex C.3, does not have the meaning given in 8.7.

SBVR Annex A.2.6 discusses verbs of change and the idea of intensional roles. But in DTV Annex C, fixed period and variable period are apparently being defined as general noun concepts. (On the other hand, 'scheduled start time' is a role that is apparently declared to be a general concept.) It may be that the business use of 'time period' IS often a role of time interval, or a schedule entry that refers to a time interval, and that the DTV use of the term is not business-friendly.

In response to Issues 18990 and 19336, the RTF decided to replace the current EU Rent example in Annex C with some examples drawn from actual business experience. So this issue is moot. Formally, it can be said to be resolved via Issue 19336