ISSUE-161: Possible ambiguity

Possible ambiguity

State:
CLOSED
Product:
Time ontology in OWL
Raised by:
Simon Cox
Opened on:
2017-04-12
Description:
From https://www.w3.org/XML/2007/qts-timeont-comments

This year, in Massachusetts, Nov. 4, 2007, 01:01 EDT will be followed by Nov. 4, 2007, 01:00 EST, which will be followed by Nov. 4, 2007, 01:01 EST. The following value appears to be ambiguous:
:example
a DateTimeDescription;
:unitType unitMinute;
:minute 1;
:hour 1;
:day 4;
:month 11;
:year 2007;
:timeZone EST.
Given that “EST” appears to denote the geographic time zone, and not in itself the offset from UTC, this appears to denote two distinct moments, one on winter time and one in summer time.
Related Actions Items:
No related actions
Related emails:
  1. OWL-Time - ISSUE-161: Possible ambiguity (from Simon.Cox@csiro.au on 2017-04-20)
  2. OWL-Time - ISSUE-161: Possible ambiguity (from Simon.Cox@csiro.au on 2017-04-12)

Related notes:

Proposed disposition, quoted from email 2017-04-20

This issue relates to the description of time positions using a particular calendar/clock system which also allows for seasonal changes in certain time-zones.

We agree that more information would be required to enable the determination of the order of seconds denoted using the calendar-clock system when the clocks change.
The question appears to conflate two issues:

(i) The identifier for the time zone

(ii) Whether the zone identified is geographic, or an offset from UTC.

On item (i) we note that the revised ontology clarifies that the time:timeZone property is an owl:ObjectProperty, with the rdfs:range time:TimeZone. Although OWL-Time no longer provides a time-zone ontology per se, it is now clear that the object of a time:timeZone property must be a resource, not just a name or label, and implicitly the resource will be denoted by a URI. The examples in the revised spec link to well curated descriptions of timezones maintained by reliable organizations.

On item (ii) we believe there is no ambiguity here - time-zone indicates offset from UTC, not geography.

We hope this resolves the issue satisfactorily.

Simon Cox, 21 Apr 2017, 02:21:21

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