To: |
"[ontolog-forum] " <ontolog-forum@xxxxxxxxxxxxxxxx> |
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From: |
"Sharma, Ravi" <Ravi.Sharma@xxxxxxxxxxx> |

Date: |
Wed, 23 Jan 2008 11:47:23 -0700 |

Message-id: |
<D09FFCFB3952074082D4280BC24EAFA89B7C4D@xxxxxxxxxxxxxxxxxxxxxxxxxx> |

PatC Yes but we as community need to converge on a convention and practice for CoP so that we can talk about different times, overlaps, periods, scales, accuracies, when we want to represent concepts and synchronize tool interoperability in future. Thanks. Ravi (01) (Dr. Ravi Sharma) Senior Enterprise Architect (02) Vangent, Inc. Technology Excellence Center (TEC) (03) 8618 Westwood Center Drive, Suite 310, Vienna VA 22182 (o) 703-827-0638, (c) 313-204-1740 www.vangent.com (04) -----Original Message----- From: ontolog-forum-bounces@xxxxxxxxxxxxxxxx [mailto:ontolog-forum-bounces@xxxxxxxxxxxxxxxx] On Behalf Of Patrick Cassidy Sent: Wednesday, January 23, 2008 1:11 PM To: '[ontolog-forum] ' Subject: Re: [ontolog-forum] Time representation (05) PatH, Thanks for the answer. The implementation of Time that I would like to use is one that I couldn't find in the Time Catalog - though I may not have interpreted all of the axioms correctly. What I would like is a representation of Time as isomorphic to the real line with: (1) open, closed and semi-open intervals, all distinguishable and specified by their endpoints (whether or not the endpoint is included in the interval) (2) a time point as a subtype of a closed time interval, and identical to a closed interval of zero length. (3) two time intervals closed at the adjoining ends both overlap and meet (I think this is not permitted in Allen's algebra); Intervals that both overlap and meet must both be closed at the meeting ends and have a single time point as the overlap interval. (4) dividing a time interval at a point gives rise (depending on the dividing operation) to either (a) two time intervals, each having a closed end with the point of division (and conversely, joining two time intervals that meet at closed ends merges the common point, which is a single ordinary point); or (b) two intervals open at the point of division; or (c) one interval (the earlier one) open and one (the later one) closed at the point of division. Operations a and b can divide an interval into two equal parts, if the starting interval ends are both closed or both open. Operation c can equally divide a closed-open interval. (5) catenating two intervals both open at the joining end creates the point of juncture. (6) Two intervals open at the adjacent ends also meet if those ends are defined by a common point (7) time points are both 'part of' and 'contained in' time intervals. (8) the default time interval type (if defaults are needed) is one closed at the lower end and open at the upper end - (This type is used to specify AM or PM in a day). (9) Events that occur at a single time point imply a preceding interval open at that point, in which the event state differs from the state at (and for some interval after) that point. Though unrealistic for physical events, this can be used to specify socially defined events, such as someone becoming president at a particular time point. (06) But I didn't see (and may have missed) a single theory that has all of those requirements in the time catalog. Is such a theory actually in the time catalog - or elsewhere? If not, is it somehow internally logically inconsistent? (07) PatC (08) Patrick Cassidy MICRA, Inc. 908-561-3416 cell: 908-565-4053 cassidy@xxxxxxxxx (09) > -----Original Message----- > |

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