UCDwordsRFM < IVOA

---+ RFM (Request for modification) of the List of UCD-words

AndreaPreiteMartinez
IVOA – Semantics WG

TN - 20060713



What follows is a list of proposed requests (*RFM*) to modify/add the present standard list of ucd-words: *The UCD1+ controlled vocabulary, Vers. 1.11 - IVOA Recommendation 31 December 2005*  (http://www.ivoa.net/Documents/latest/UCDlist.html ). 

The RFMs were collected over the past few month, from suggestions coming from various members of the IVOA community. 
The list has been presented at the UCD-session in Victoria, and corrected taking into account the discussions during the meeting within the WG and with the Theory IG. Other suggestions have been added to describe attributes used by some Data Models.

The list is open for discussion in accordance with the approved standard procedure: *Maintenance of the list of UCD words, Version 1.20 - IVOA Recommendation 28 May 2006* (http://www.ivoa.net/Documents/latest/UCDlistMaintenance.html ).

Due to web security problems, for the moment we discourage the usage of the web-based form for submitting RFMs. On the other hand we can consider the present list of RFMs as a collective effort of the community, not requiring a private personal answer (see par. 2.2 and 2.3 of the maintenance document). For the time being, all the RFMs and all the corresponding answers will be grouped together in the present public document. Other RFMs could be proposed during the discussion phase, so that we can consider this document as a temporary repository of all proposed RFMs. 






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---+ A proposed new UCD1+ time-branch

---++ A more consistent approach to the description of time-related quantities with UCDs.


AndreaPreiteMartinez, IVOA – Semantics WG

---+++ TN - 20060701




The *time* branch in the IVOA Rec v1.11 is the following:


| *SF* | *word* | *description* |
| Q | time                               | Time |
| Q | time.age                           | Age |
| Q | time.crossing                      | Crossing time |
| Q | time.epoch                         | Epoch, julian date |
| Q | time.equinox                       | Equinox |
| Q | time.event                         | Duration of an event or phenomenon |
| Q | time.event.end                     | End time of event or phenomenon |
| Q | time.event.start                   | Start time of event or phenomenon |
| Q | time.expo                        | Exposure on-time, duration |
| Q | time.expo.end                      | End time of exposure |
| Q | time.expo.start                  | Start time of exposure |
| Q | time.interval                      | Interval of time |
| Q | time.lifetime                      | Lifetime |
| Q | time.obs                           | Observation on-time, duration |
| Q | time.obs.end                      | End time of observation |
| Q | time.obs.start                     | Start time of observation |
| Q | time.period                        | Period |
| Q | time.phase                         | Phase |
| Q | time.relax                         | Relaxation time |
| Q | time.resolution                    | Time resolution |
| Q | time.scale                         | Timescale |

The request is to introduce a clearer separation between *instant* of time and *duration* in time.


The situation now is:

The words referring to *instants* of time are:

time.epoch %BR%
time.event.end %BR%
time.event.start %BR%
time.expo.end %BR%
time.expo.start %BR%
time.obs.end %BR%
time.obs.start

The words referring to a *duration* or an interval of time are:

time.event %BR%
time.expo %BR%
time.obs %BR%
time.interval

(but in this last case we mean a time-bin, or the time elapsed between two events, not the duration of an event. We need to make the description clearer)

In addition we have some other rather specific time-words that we leave untouched. 


---++ Proposal: 

we keep the atoms indicating instants:%BR%
epoch, %BR%
start, %BR%
end  %BR%    
(although a strict hierarchization should give: 
epoch, epoch.start, epoch.end !!)

and we introduce a new atom  *duration*  to indicates duration, interval of time during which a generic event/observation/phenomenon is taking place.

We keep the atoms indicating what instants and duration we are referring to:%BR%
obs (observation)%BR%
expo  (exposure)%BR%
event  (generic event, pleonastic!)%BR%
and introduce a new atom 
*sequence* (to indicate a correlated sequence of observations)

One possible combination of atoms is:

*time*,   at level 1%BR%
*instants/duration*   at level 2%BR%
*type of event described*   at level 3


Examples:

| *Description* | *v1.11* | *new version* |
| time/date of observation | time.epoch | time.epoch.obs |
|  or:  | time.epoch;obs | time.epoch;obs |
| observing time | time.obs | time.duration.obs |
|   or:   | time;obs | time.duration;obs |
| exposure time | time.expo | time.duration.expo |
| start time of a sequence | time.obs.start | time.start.sequence |

In addition, we propose three more atoms to describe creation, publication/release and processing times for data, files, catalogues, etc.


The new proposed *time* branch is illustrated in the following Table. New ucd-words and new descriptions are in italic. Old (v1.11) ucd-words that are not repeated in column *new version* are suppressed.



---+++ Table 1.  The proposed new **time** branch in UCD1+.

| *SF* | *word in v1.11* | *new version* | *description* |
|Q|time|time|_Generic quantity in units of time or date_|
|Q|time.age|time.age|Age|
|Q||_time.creation_|_Creation time/date (of dataset, file, catalogue,...)_|
|Q|time.crossing|time.crossing   |Crossing time|
|Q||_time.duration_|_Interval of time describing the duration of a generic event or phenomenon_|
|Q||_time.duration.event_|_Interval of time describing the duration of an event (pleonastic, see above)_|
|Q||_time.duration.expo_|_Interval of time describing the duration of an exposure, on-time_|
|Q||_time.duration.sequence_|_Interval of time describing the duration of a correlated sequence of observations/events_|
|Q||_time.duration.obs_|_Interval of time describing the duration of an observation_|
|||time.duration;obs|(Alternative form)|
Q      time.end   End time/date of generic event
Q      time.end.event   End time/date of event (pleonastic, see above)
Q      time.end.expo   End time/date of exposure
Q      time.end.sequence   End time/date of a correlated sequence of observations/events
Q      time.end.obs   End time of observation
      time.end;obs   (Alternative form)
Q   time.epoch   time.epoch   Instant of time related to a generic event (epoch, date, Julian date, time stamp/tag,...)
Q      time.epoch.event   Instant of time/date related to an event (pleonastic, see above)
Q      time.epoch.expo   Instant of time/date related to an exposure
Q      time.epoch.sequence   Instant of time/date related to a sequence of observations/events
Q      time.epoch.obs   Instant of time/date related to an observation
      time.epoch;obs   (Alternative form)
Q   time.equinox   time.equinox   Equinox
Q   time.event      Duration of an event or phenomenon
Q   time.event.end      End time of event or phenomenon
Q   time.event.start      Start time of event or phenomenon
Q   time.expo      Exposure on-time, duration
Q   time.expo.end      End time of exposure
Q   time.expo.start      Start time of exposure
Q   time.interval   time.interval   Time-bin, or the time elapsed between two events, not the duration of an event
Q   time.lifetime   time.lifetime   Lifetime
Q   time.obs      Observation on-time, duration
Q   time.obs.end      End time of observation
Q   time.obs.start      Start time of observation
Q   time.period   time.period   Period, interval of time between the recurrence of phases in a periodic phenomenon
Q   time.phase   time.phase   Phase, position within a period
Q      time.processing   A time/date associated with the processing of data
Q   time.relax   time.relax   Relaxation time
Q      time.release   The time/date data is available to the public
Q   time.resolution   time.resolution   Time resolution
Q   time.scale   time.scale   Timescale
Q      time.start   Start time/date of generic event
Q      time.start.event   Start time/date of event (pleonastic, see above)
Q      time.start.expo   Start time/date of exposure
Q      time.start.sequence   Start time/date of a correlated sequence of observations/events
Q      time.start.obs   Start time of observation
      time.start;obs   (Alternative form)
         



In Table 2 we list the suppressed ucd-words, and the new words replacing them.

---+++ Table 2. Proposed suppressions / replacements


|*SF*|*suppressed*|*replacement*|*description*|
Q   time.event   time.duration[.event]   Duration of an event or phenomenon
Q   time.event.end   time.end[.event]   End time of event or phenomenon
Q   time.event.start   time.start[.event]   Start time of event or phenomenon
Q   time.expo   time.duration.expo   Exposure on-time, duration
Q   time.expo.end   time.end.expo   End time of exposure
Q   time.expo.start   time.start.expo   Start time of exposure
Q   time.obs   time.duration.obs   Observation on-time, duration
Q   time.obs.end   time.end.obs   End time of observation
Q   time.obs.start   time.start.obs   Start time of observation
         







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This topic: IVOA > UCDwordsRFM
Topic revision: r3 - 2006-07-13 - AndreaPreiteMartinez