[Crm-sig] Homework Issue 288
Martin Doerr
martin at ics.forth.gr
Sun Jan 7 23:34:30 EET 2018
Dear All,
Here my guidelines:
Guidelines for using P82a, P82b, P81a, P82b
Jan 7, 2018
The range of properties "P81_ongoing_throughout" and
"P82_at_some_time_within" isdefined in the CRM as E61
<#_E61_Time_Primitive> Time Primitive, i.e., (closed, contiguous)
intervals on the natural time dimension in which we live.
Since the E61 Time Primitive of the CRM cannot directly be implemented
in RDF databases, we define in the official RDF implementation of the
CIDOC CRM four properties replacing P81 and P82 adequately using
xsd:dateTime.
Property P81 describes the maximum known temporal extent of an E52
Time-Span, i.e. the extent it is ongoing throughout. It is replaced in
this RDF version by the property "P81a_end_of_the_begin"and
"P81b_begin_of_the_end", to be used together.
"P81a_end_of_the_begin" should be instantiated as the earliest point in
time the user is sure that the respective temporal phenomenon is indeed
ongoing. We call it “end_of_the_begin”, because it also constitutes an
upper limit to the end of the indeterminacy or fuzziness of the begin of
the described temporal phenomenon.
"P81b_begin_of_the_end" should be instantiated as the latest point in
time the user is sure that the respective temporal phenomenon is indeed
ongoing. We call it “begin_of_the_end”, because it also constitutes a
lower limit to the begin of the indeterminacy or fuzziness of the end of
the described temporal phenomenon.
It is correct to assign the same value to P81a_end_of_the_begin and
P81b_begin_of_the_end, if no other positive knowledge exists. It is also
correct not to instantiate P81 for a time span, if no respective
evidence is known.
If a respective reasoning is installed, and no evidence exists that the
phenomenon was definitely ongoing at any point in time, one may use a
value for P81a_end_of_the_begin greater than for P81b_begin_of_the_end,
indicating that the indeterminacy of knowledge (not of being) of the
begin overlaps with the indeterminacy of knowledge (not of being) for
the end [see Christian-Emil Ore XXX].
If a value for P81a_end_of_the_begin is given with a precision less than
that of xsd:dateTime, such as in days or years, the implementation
should “round it up” to the last instant (second) of this time
expression, e.g. 1971 = Dec 31 1971 23:59:59. Respectively, if a value
for P81b_begin_of_the_end is given with a precision less than that of
xsd:dateTime, such as in days or years, the implementation should “round
it down” to the last instant (second) of this time expression, e.g. 1971
= Jan 1 1971 0:00:00. If values are needed that are not within the range
or precision of xsd:dateTime, e.g., for paleontology, this property
should be extended with another, suitable data type.
Property P82 describes the narrowest known outer bounds of the temporal
extent of an E52 Time-Span, i.e. the extent it is ongoing “at some time
within” this interval. It is replaced in the official RDF version by the
properties "P82a_begin_of_the_begin" and "P82b_end_of_the_end", to be
used together.
" P82a_begin_of_the_begin " should be instantiated as the latest point
in time the user is sure that the respective temporal phenomenon is
indeed not yet ongoing. We call it “begin_of_the_begin”, because it also
constitutes a lower limit to the begin of the indeterminacy or fuzziness
of the begin of the described temporal phenomenon.
" P82b_end_of_the_end " should be instantiated as the earliest point in
time the user is sure that the respective temporal phenomenon is indeed
no more ongoing. We call it “end_of_the_end”, because it also
constitutes an upper limit to the end of the indeterminacy or fuzziness
of the end of the described temporal phenomenon.
It is not correct to assign the same value to P82a_begin_of_the_begin
and P82b_end_of_the_end. If a value for P82a_begin_of_the_begin is given
with a precision less than that of xsd:dateTime, such as in days or
years, the implementation should “round it down” to the last instant
(second) of this time expression, e.g. 1971 = Jan 1 1971 0:00:00.
Respectively, if a value for P82b_end_of_the_end is given with a
precision less than that of xsd:dateTime, such as in days or years, the
implementation should “round it up” to the last instant (second) of this
time expression, e.g. 1971 = Dec 31 1971 23:59:59.
It must always hold that the value for P82a_begin_of_the_begin is less
than P82b_end_of_the_end, P81a_end_of_the_begin and P81b_begin_of_the_end.
It must always hold that the value for P82b_end_of_the_end is greater
than P82b_end_of_the_end, P81a_end_of_the_begin and P81b_begin_of_the_end.
P82a_begin_of_the_begin and P82b_end_of_the_end should always be
assigned a value to for any past phenomenon, albeit unrealistically far
away from reality. It is an error to associate any quality of positive
knowledge with these values. The scholarly practice not to give any
outer bounds for an event, because it is, for instance, not known down
to a precision of three years, is not helpful for automated reasoning.
In that case, the machine may regard that the event has possibly
happened at the time of the dinosaurs.
Please improve.
Cheers,
Martin
--
--------------------------------------------------------------
Dr. Martin Doerr | Vox:+30(2810)391625 |
Research Director | Fax:+30(2810)391638 |
| Email: martin at ics.forth.gr |
|
Center for Cultural Informatics |
Information Systems Laboratory |
Institute of Computer Science |
Foundation for Research and Technology - Hellas (FORTH) |
|
N.Plastira 100, Vassilika Vouton, |
GR70013 Heraklion,Crete,Greece |
|
Web-site: http://www.ics.forth.gr/isl |
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