Changes between Version 23 and Version 24 of BluePrintVITA
- Timestamp:
- 12/23/09 19:23:09 (15 years ago)
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BluePrintVITA
v23 v24 20 20 === Person Entity === 21 21 22 == = Presence ===22 == Presence Log == 23 23 24 Presence is the fact, that an entity is physically there at a particular location at a particular time. This abstract construction covers even cases of explicit absence, i.e. when the entity is not present at that time at that location.24 Presence means the fact, that an entity is physically there at a particular '''location''' at a particular '''time'''. This abstract construction covers even cases of explicit absence, i.e. when the entity is ''not'' present at that location at that time. 25 25 26 A presence is established through a recognition event, that iswhen the entity is recognized by a dedicated observer (human or automatic).26 VITA applications record a presence log for each person entity. Each log entry is established through a recognition event, i.e. when the entity is recognized by a dedicated observer (human or automatic). 27 27 28 28 Recognition can happen implicitly, e.g. when other data are obtained directly from the entity. In these cases, the time and location of the observer are used to establish a presence. 29 29 30 30 Recognition can happen explicitly, i.e. in response to observation requests. In these cases, the time and location as determined by the request are used to establish a presence. Explicit recognition events may lead to establishment of explicit absence (=this one not here now). 31 32 Locations in presence records represent geospatial features, which can basically be of any valid feature class (points, polygons, lines etc.). Where references to locations are used in communications, they must be universally unique and resolvable; otherwise the referred geospatial information have to be enclosed in the communication. 33 34 In contrast to that, ''time'' in this regard means one exact time point, to be stored as coordinated universal time (UTC, Gregorian date including century) with a minimum precision of one second. Relative times must not be used. 31 35 === Identity === 32 36