[Crm-sig] Fwd: ISSUE 240: Start/End vs Period of Existence
On Wed, Apr 23, 2014 at 4:08 PM, martin wrote: > > We adopted Allen's temporal logic, probably prematurely, thinking we could > rely on > a well received theory. In the meanwhile, it turns out that Allen's logic > does not work > properly both for fuzzy dates and for incomplete knowledge. There are > temporal relations > which come from observation, but can only be represented by OR > combinations of Allen's > relationships. That causes problems in RDF - we need superproperties of > Allen's to represent > an OR. The other problem is that equality in time can only come from > numerical declaration > of a date, but not from observation, except if the event is identical. > Pat Hayes's catalog of temporal theories may help clarify things. Section 4.1 et. seq. are particularly relevant, but it's better to read the whole thing. Hayes, PJ (1996) A Catalog of Temporal Theories. Technical Report UIUC-BI-AI-96-01, University of Illinois. http://www.ihmc.us/users/phayes/docs/timeCatalog.pdf Some axiomatizations have been further refined by Gruninger and Ong - see e.g. http://stl.mie.utoronto.ca/publications/colore-time.pdf See the colore ontology repository at https://code.google.com/p/colore/ e.g. https://code.google.com/p/colore/source/browse/#svn%2Ftrunk%2Fontologies%2Fapproximate_point Simon
Re: [Crm-sig] ISSUE 240: Start/End vs Period of Existence
Hi Vladimir, We are converging ;-) . We would in any case require activities at least intentionally not to stop. In case the "floruit" splits in different phases or very different fields, it should be more than one floruit instance per person. This may need more precise definition of identity conditions. "Life" as pure spacetime volume is pretty useless to connect events to a person. Obviously, all events a person was present at intersect with its life. So, there is no additional information in modelling "life". When do you need it really? Best, Martin On 23/4/2014 2:57 πμ, Vladimir Alexiev wrote: Martin> Use of an identifier and the floruit of a person is explicitly modelled in FRBRoo v2.0. Thanks! I see it now (F51 Floruit) - in BM we modeled Profession and Nationality as a group. - It's interesting that Floruit has something very general: R59 had typical subject: E1 CRM Entity - In contrast, F52 Name Use Activity has R62 was used for membership in: E74 Group, and R61 occurred in kind of context: E55 Type - If Floruit is modeled, surely Life merits to be modeled :-) Then again, it's a simple case of Floruit, one with e.g. P2 has type: a E55 Type, OR R59 had typical subject: a E55 Type Yes, it is intentional that states that can only be acquired by explicit events, such as ownership, membership etc., are described by these events. This is to ensure monotonicity under increase of incomplete, but consistent knowledge. After reading CRMgeo and these emails a couple of times, I now grok what's "monotonicity of states". What I called "Periods of Existence" are Spatiotemporal Volumes. These can be discontinous, right? One can start an activity, suspend it, continue it somewhere else, etc. The monotonic accumulation of start/end events corresponds to potentially non-monotonic update of Spatiotemporal Volumes (split into smaller volumes, remove some part). OWLIM rules are monotonic, so I agree with the goal to uphold monotonicity. events are the hooks for other, distinct, historically relevant information. Birth and death have quite different contexts and actors involved. Agree. How about this Floruit: "Being a set and costume designer, a painter, an illustrator, and a poet in Russia and France in the first half of the 20th century [general fields of activity of Natalya Goncharova]" Maybe it's interesting and historically relevant who helped her *become* a costume designer, and what caused her to *stop* being a costime designer? I'm concerned that you end up with many ideosyncratic solutions, and no common pattern: - E15 Identifier Assignment is two start/end events in one: deassignment of old identifier, and assignment of new one. - F52 Name Use Activity is a period of use (spatiotemporal volume = period of continued use of an Appellation) - both are subclasses of E13 Attribute Assigment I find this confusing: - If I say the time-span of F52 Name Use Activity is from 2000 to 2014, it means someone used that name for a period of 14 years. - But if I say the same of E15 Identifier Assignment, it means whatever committee did this assignment, really took their sweet time and were in no hurry (14 years to decide ;-). And I can attest that Josh@BM got confused, he thought assigned/deassigned of E15 somehow mean start/end, but they mean new/old Or consider modeling the military service of a Person in a Group: http://en.wikipedia.org/wiki/Ricardo_C._Binns It can be done with these statements: - a E85 Joining; P143 joined ; P144 joined with ; P4 has time-span [P82 "1963"] - a E86 Leaving; P145 separated ; P146 separated from ; P4 has time-span [P82 "1966"] Or this one: - a F51 Floruit; P14 carried out by ; R59 had typical subject ; P4 has time-span [P82a "1963"; P82b "1966"] Observations: - Monotonicity means that the is stronger: also means there were no intervening leaving/joining between 1963-1966. If there were (like for this nicely moustached fella http://en.wikipedia.org/wiki/Henry_Pierson_Crowe) then we'd need to model the Floruit as a discontinuous Period (having parts). - are stronger than , since joining/leaving express Membership, while R59 is only some general kind of relatedness. I'd say: John Dover Wilson's activity as a Shakespeare scholar (F51) R59 had typical subject William Shakespeare (F10) is quite different from: Ricardo Binns' activity as a USMC soldier ;-) - R59 is not a subprop of P14 carried out by, nor P107 has current or former member. So if you want to query both, you need branches in your query, or Fundamental Relations to do it - Note: R59 says it's Subproperty of: P2 has_type / P92 brought into existence (was brought into existence by): E77 Persistent Item. P2_has_type/ P94 has created (was created by): E89 Propositional Object.P129 is about (is subject of): E1 CRM Entity which is some confused property chain notation, but surely it can be stated explicitly too - Most
Re: [Crm-sig] ISSUE 240: Start/End vs Period of Existence
Hi Vladimir, The important thing to discuss is what the semantics of "starts" and "ends" are. We adopted Allen's temporal logic, probably prematurely, thinking we could rely on a well received theory. In the meanwhile, it turns out that Allen's logic does not work properly both for fuzzy dates and for incomplete knowledge. There are temporal relations which come from observation, but can only be represented by OR combinations of Allen's relationships. That causes problems in RDF - we need superproperties of Allen's to represent an OR. The other problem is that equality in time can only come from numerical declaration of a date, but not from observation, except if the event is identical. If we remove exact equality, we can create a set of observable relationships purely in time. Then we can think of more causal relationships. The meaning of "starts / finishes" in Allen's relationships appears to be that of an initial or final phase. No assumptions about orders or magnitude. We use this to say: Early Minoan "starts" Minoan, etc. In that case, as you suggested, it implies parthood, but not a "starting" in your sense. There are other cases, in which the start of a Period is marked by scholars by an event, which does not necessarily imply it was the reason for what follows, such as the lightning that burned the palace in Beijing in 1425(?), which was taken as sign of the heaven for China to stop exploring the oceans. For us most relevant are wars. For instance, the taking of Antioch by the Crusaders http://en.wikipedia.org/wiki/Siege_of_Antioch ended the muslim rule in the city and started the new rule. It has a detailed history of its own. The battle cannot easily be taken as part of either period, even though we may have to regard the battle actaully as the overlap of both periods. This proceeds over time through the space of the city itself. Must any point in the space of a period be reachable by a messenger of that time from the start event? (doves!). If pregnancy starts life of a human, birth can be seen as the end of the start of life. We need clear semantics to decide what "starts" means. Pregnancy is an event for the mother and the embryo. Before talking about momentary or not start events, let us consider what the needs are to increase the CRM, which is already so big that we loose most of our potential customers. Comments/ ideas welcome! On 22/4/2014 5:57 μμ, Vladimir Alexiev wrote: Steven> We also consider it axiomatic that no event is "momentary": all temporal events have duration. Martin> "momentary events" are a fiction of computer science. A basic requirement for the CRM is that it is scale-invariant. There is no smallest granularity for events we could easily point to. That's why I put "momentary" in quotes. My point is that Birth & Death are (several) orders of magnitude smaller than Life. All time-points of Birth must be close to the *begin* points of Life. (Birth.P82a & P81a & P82a & P82b must both be close to Life.P82a & P81a) You wrote: - Start/End are considered "momentary" events, thus have only 2 points (P81a=P82a, P82b=P81b) This is a misinterpretation I fear. P81a/b may be unknown, but never equal to P82. It doesn't matter whether you'll consider Birth a momentary event, or daily, or 9-monthly: under any reasonable scale assumption (uniformly applied to Birth and Life)), this peculiar relation between Birth and Life will hold. And this is no coincidence: Birth/Death are the start/end events of Life. From some "cultural-topological" viewpoint: - Birth/Death are spatiotemporal points, if Life is a spatiotemporal curve - Birth/Death are spatiotemporal spheres, if Life is a spatiotemporal "curved cylinder" It is exactly this relativity with respect to an arbitrary scale of view we forbid in the CRM. This is a major violation of interoperability. Allen relationships have only temporal meaning, they are accidental Exactly: currently there's no good way to express the peculiar relation between Birth and Life. If the Allen property holds ( P116_starts ), it does not constrain the *end* points of Birth sufficiently. P116_starts is just as true (though vacuous) as P116_starts . Martin> life of a person is one of the candidates for a period with start/end events, but, is it a "Period" or just the spacetime volume of the person? I'm just digging through CRMgeo, so I know what you mean, and I think it is the spacetime volume. And Birth/Death are the start/end of that volume... So why in CRM we can talk about the start & end, but we can't talk about the volume as a whole? Whereas in CRMdig it's the opposite: we have crmgeo:SP8_Spacetime_Volume but we cannot talk about its start/end points. Well, the semantic question is if "life" is the total of one's actions and events suffered, or just where the body and the limbs are. Do volumes have innate start & end? Well surely Time-Spans do. Surely not! The beginning of a
