On 14 Feb 2014, at 22:03, Barkmeyer, Edward J <edward.barkmeyer@xxxxxxxx> wrote: (01)
> Matthew West wrote:
>
>> If you are objecting to a temporal part of a state, that would depend upon
>> what meaning of "state" you are using.
>>
>> A state (State1) could be a set of properties, in which case a state is
>> timeless, can not have a temporal part,
>> and may be possessed by different entities at the same or different times.
>
> [EJB] I think of the set of properties as a classifier/predicate State1 and
>everything Matthew says is then true of State1, but I agree that people do use
>the term 'state' in this sense.
>
>>
>> A state (State2) could be a situation of some individual being in (State1).
>
> [EJB] That is, a slice of space-time in which State1(X) holds for a given
>individual X.
>
>> This could be an instantaneous state (State2a), an extended situation
>> during which the individual is in that state (State2b), or the maximal
>> temporal situation during which the individual is in that State1 (State2c).
>>
>> A State2a can not have a temporal part. A State2b can have a State2b
>> as a temporal part for which they both share a State1. A State2c can
>> not have a State2c as a temporal part if they both share the same State1.
>>
>> A State2c can have a State2c as a temporal part if the second State2c
>> has a more detailed State1 (e.g., the first State1 is that the oil
>> temperature is
>> between 140C and 160C and the second State1 is that the oil temperature
>> is between 150C and 155C). In this case the second State2c is a temporal
>> part of the first State2c.
>
> [EJB] Ah! This is the problem.
>
> I understand 'S is a temporal part of X' to mean: there is some
>characterization C such that C(X) holds over a time interval T, and S is
>understood to be the triple holds(C, X,T). And S1 is a different temporal
>part of X iff S1 = holds(C1, X, T1) for some C1 and T1, where Not (C1 = C) or
>Not (T1 = T). There are clearly other possible relationships of interest, to
>wit C1 implies C (class C1 is a subclass of C), T1 is a subinterval of T, and
>S1 is a part of S2, where X1 is a part of X2, and holds(C2, X2, T1) implies
>holds(C1, X1, T1), i.e. a state of the whole (X2) implies a state of a part
>(X1). [this is what I meant about the need for axioms that describe
>isTemporalPartOf.]
>
>> From the example below, Matthew apparently uses 'S is a temporal part of X'
>to mean: S is a state/situation that involves X in some role, which is just a
>generalized view of "some C(X) holds".
>
> But what Matthew says here is that S2c is a temporal part of S (not X!) if
>S2c = holds(C1, X, T1) and C1 implies C and T1 is-within T! I would expect
>that temporalPartOf(S2c, S) would mean there is a C1 and a T1 such that
>holds(C1, *S*, T1) ! In the generalized view, S2C (X having the narrower
>temperature range) plays a role in S (X having the broader temperature range).
> I don't understand the ontological commitment that permits S2c to be viewed
>as playing a role in S. So, I don't know what temporalPartOf means! (02)
If what you're getting from MW is that "temporal part of" means "there is some
characterization C such that C(X) holds over a time interval" then step back
... that is not what it means. No such characterization is necessary when
creating parts and temporal part of relations. (03)
'S temporal part of X' means 'S is a time slice of X' ... nothing more. To make
that time slice interesting, there are sometimes characterisations that hold,
but in other cases not. For example, in our Oil and Gas reporting app "NJORD A
Platform during January 2013" is interesting and is TPO "NJORD A Platform
during 2013" which is also interesting, but there is no additional
characterisation ... they are just both interesting time slices (i.e. TPO) of
the same whole-life thing "NJORD A Platform whole-life". (04)
So given triples (05)
X a PossibleIndividual (with beginning and ending, and may be whole-life or not)
S a Possible Individual (with beginning and ending within period of X beginning
and ending)
S TPO X
C a Class
S a C (06)
there need not be any relation between "S a C" and "S TPO X" or between X and C
at all. In my example, "NJORD A Platform during January 2013" may have stopped
production of oil due to repair. However, that repair is only related to the
part, not the larger part or the whole-life platform. It could also have been
the case that the app only ever reported data monthly so the "NJORD A Platform
during 2013" individual and TPO relationship would never have been
instantiated. If you simply take "temporal part of" literally then you are
likely to get it right. The relation could have been "temporal part of based on
characterization" and all this discussion would follow ... but that's not what
15926 says. (07)
Clearly there's are philosophical debates, as described in
https://en.wikipedia.org/wiki/Temporal_parts, but 15926 TPO is the same
relation described in that Wikipedia article and it is reasonably well-defined
as a position. (08)
Cheers,
David (09)
>
>> ...
>>> [MW] Consider the temporal part of pump with serial no. P1234
>>> (materialized physical object) that is installed as tag 21P101 (functional
>>> physical object). It is a temporal part of each of these, not just one.
>>> The thing to note is that they are two different types of whole life
>>> individual, but you need all the elements of the type.
>
> If S is a temporal part of the FPO named 21P101, then S =
>holds(instantiatedByP1234, 21P101, T) for some T. And if S is a temporal part
>of the Pump named P1234, then S = holds(placedAs21P101, P1234, T) for the same
>T. What we really have here is that instantiatedBy(fpo, po) = placedAs(po,
>fpo), or more accurately: forall (T) instantiatedBy(fpo, po, T) iff
>placedAs(po, fpo, T). So the State S is an instance of both ternary
>relations. And S can be described as a temporal part of both the pump and the
>place. And to carry any semantics, S must be an instance of the class
>Placement, or something like that. Further, the fact that S is a temporal
>part of Pump and Place tells me how to formulate the relation, but only
>because the 'types' of the arguments to placedAs are disjoint.
>
> Now, let us consider flowsInto(equipment1, equipment2). And suppose that at
>time T, Pump P1234 is connected to HeatExchanger H5678, in such a way that the
>process fluid flows from P1234 to H5678. Then we have a FlowsInto state that
>is a temporal part of P1234 and a temporal part of H1234 for the same time
>interval T. But which is the source and which is the destination? They are
>both Equipment, so we can't tell. This is admittedly contrived. But the
>problem is intrinsic. The state that is a temporal part of two things
>represents a ternary relation that involves them in distinct roles over a
>common time interval. In general, the types of the non-temporal arguments to
>the ternary relation represented by the state may not be distinct. So the
>relationship between the State and the participants is not just
>isTemporalPartOf, but rather some refinement of it that represents each role
>in the ternary relation.
>
> Using a language in which the only relationship to a State is
>'isTemporalPartOf', the solution will be to create things that are instances
>of a class representing a role in the state, and make the role things temporal
>parts of the role players and also temporal parts of the state thing. So we
>have a FlowSource that is a temporal part of the Pump and the FlowsInto state,
>and FlowDestination that is a temporal part of the HeatExchanger and also a
>temporal part of the FlowsInto state. Thus the state thing involves things of
>two distinguished types, and the ternary relation can be properly
>reconstructed. It is a work-around, and most modeling languages force such
>contrivances from time to time. But coupled with the above confusion about
>relationships between states, I can't be sure that anyone can reconstruct the
>intent of 'isTemporalPartOf'.
>
> Famous last words: "It is not how I would have modeled it, but it works."
>This is knowledge engineering in which the knowledge is contorted by the
>engineering.
>
> -Ed
>
>
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