- From: Alan Rector <rector@cs.man.ac.uk>
- Date: Tue, 12 Oct 2004 08:15:28 +0100
- To: Natasha Noy <noy@SMI.Stanford.EDU>
- CC: Christopher Welty <welty@us.ibm.com>, public-swbp-wg@w3.org
All I think I agree with Natasha on priorities. Clearly * Closure axioms - a very short note but essential * Numbers and numeric ranges - badly needed * String values - names etc. Also badly needed * Other datatype properties - priority? * Transitive properties and part-of - I suggest this as a two part note, the first high priority, the second much lower. Part 1: Transitive properties and one simple part-of relation plus the note that for many purposes we want "Thing or is_part_of Thing" because we don't have reflexive relations. Postscript that part-of is not containment, attachment, membership, etc and comes in different flavours to be covered in a separate note. Part 2: A simple example schema for different kinds of parthood, containment, location, membership, etc. showing the use of the property hierarchy. Were I to do it, I would adapt the scheme in http://www.cs.man.ac.uk/~rector/ontologies/simple-top-bio/ I am happy to take the lead on part-wholes Part 1 and closure axioms but it would have to be over end Dec early Jan. (Closure axioms I might try to get done sooner, if I get the tutorial finished. It should take an afternoon for the first draft or less.) Regards Alan Natasha Noy wrote: > Chris, Alan, OEP-ers, > > What is the target audience for our notes? I know that we don't have > any practical way of answering this question, but we have to make an > educated guess. My guess is as good as anyone's, but my feeling is that > there are a lot more people looking for notes on very simple stuff > rather than something large and more complicated, as many things in > Chris's list are. Of course it's much more interesting for _us_ to > write notes on non-trivial stuff, but I am not sure we'll be getting > more people on board with these. If people are struggling with getting > even very simple things right in developing their ontologies (as many > on the protege-owl list are, for instance), they won't be very much > interested in many different types of part-of or an ontology of time. > And these are the people who we probably need to help if we want to > have the critical mass of content on the SW. > > Of course, having all the notes that Chris has suggested would be good, > but I am not sure many of them take higher priority than some simpler > ones: > > - Numeric ranges -- really, really need this one! > - Closing axioms -- without that, classifiers would seldom produce > anything useful and if anyone wants to promote the DL abilities of OWL > (admittedly, I am not one of those people :), you need to tell people > how to get even simple things work. Alan has tons of these, in addition > to closing axioms > - Simple note on units and measures. This came up at one of the recent > telecons: suppose I have an ontology on units (presented in a different > WG note or just something I have), how do I represent the fact that > John's height is 6 feet (and 180 cm) in OWL? I think this is different > from the note that Chris was referring to. > - Part of -- I am all for producing a simple version of partOf that > Evan suggested first. > > These are all much more light-weight (and less fun to write :) than the > ones Chris suggested. It doesn't have to be either/or, but we'll > probably have to set some priorities, given the limited resources that > we have. > > Natasha > > On Oct 11, 2004, at 1:13 AM, Alan Rector wrote: > > > Chris, All > > > > Can I add something like - > > > > a) options for using Ontologies in applications - whether in OWL or > > RDF - this is the thing the SWBP really has to crack. Picking up > > where Classes as Values left off. I am not sure where pointers to > > specific tricks with current technology fit in, but in the > > "deployment" part of SWBP&D I think many people would welcome a list > > of tool combinations that were known to work, however time limited > > that list will inevitably be. I am certainly not in a position to > > produce such a list; I don't think the list per se is really part of > > OEP, but we need someplace where we coordinate the principles the > > notes with practice.. > > > > b) When to use a reasoner and normalisation. > > > > c) I am not sure whether it is a note, but it is worth pointing > > people at 'common pitfalls'. One contribution towards that is > > > > > > Other comments below... > > > > > > > > Christopher Welty wrote: > > > > ... > > The partOf relation. There really isn't that much that can be "said" > > in OWL (and therefore less in RDF) regarding the typical > > axiomatizations of partOf, but knowing the different kinds of partOf > > relations and what they are supposed to mean would be useful. I'm > > hoping that some subset of Nicola, Alan, and I can take the lead on > > this one, but I also see the need for a couple of notes here, so I > > think this needs further discussion. For example Deborah expressed > > interest in a simpler note (less ambitious but quicker turnaround) on > > geographical containment. > > I am happy to take a major role in this, but not until after 6 Dec > > (ISWC plus a major week-long teaching stint - some of which will > > include material on partonomy.) I shall also be writing a paper on > > the topic or probably two. > > > > On the other hand, partonomy is a big topic. The trick is to keep > > it simple for the simple cases. I suggest that we need at least two > > kinds of notes or note fragments. > > > > 1) Notes laying out the classic distinctions, pointing to the the > > literature on merology, and pointing out things like that most users > > of partonomy probably want something that is time specific - X is a > > part of Y at some implied time T (the type is a part of the car now, > > but it may not be after the tyre has been changed) - or normative (Xs > > are considered parts of Ys). You need one or the other to avoid > > getting into issues about amputated fingers, cat's tails, etc. Also I > > think we have to say that this area is far from settled so we are > > giving guidance on workable principles plus caveats for controversies. > > > > 2) Implementation mechanisms. Transitive properties for simple > > things. SEP triples are related trickse.. > > > > RegionOfFrance = France or restriction(is_geographical_region_of > > someValuesFrom(France))] > > > > property hierarchies showing different relations between containment, > > location and partonomy. > > > > 3) Also warnings that with current classifiers (possibly excepting > > FaCT++ but we aren't sure yet) large ontologies containing extensive > > networks linked by both has_part and is_part_of (or any other > > transitive relation and its inverse) are potentially combinatorially > > explosive. If anybody does try to use a classifier it is > > disconcerting to see what seemed to work for a toy run indefinitely > > for something real. > > > > > > > > > > Units and measures. There has been some work on this, including in > > Cyc, Tom Gruber's ontology in Ontolingua, and Helena Sofia-Pinto did a > > nice one for the old SUO effort. Evan was interested in this and it > > certainly makes sense to have someone at NIST do it. > > > > Subjects. The notion of what a subject "is" and what the "subjectOf" > > relation means can be quite confusing. I have done a lot of work on > > this and am willing to take this one on, however I will want to do one > > at a time. > > > > Time. Jerry Hobbs has done a very thorough job putting together a > > consensus ontology of time based on a lot of existing time ontologies, > > most of which draw from the Allen calculus. The ontology is expressed > > in FOL (KIF), but there are (necessarily simplified) DAML+OIL and OWL > > ("OWL-Time") versions available. Jerry has expressed interest in > > seeing this as a W3C note. > > I'd be very interested in seeing this. > > > > > > Fluents. Closely tied to the notion of time is being able to say > > that a binary property "holds" for a time. e.g. one may want to say > > that "Chris is a member of the W3C from Sept, 2004 - Sept 2005". A > > property like memberOf is a fluent because it can be said to hold at a > > time (this is not strictly a correct definition, but it will > > suffice). While OWL-Time let's you represent a time interval like > > "Sept, 2004-Sept, 2005", it remains neutral wrt what happens at or > > during such a time interval. The typical move in FOL is to use a > > function or add an argument to the predicate, e.g. memberOf(Chris, > > W3C, time-interval-1), however clearly we can't do that in OWL or RDF, > > since we are limited to binary predicates. One solution is to go for > > full reification of fluents, as in the exsiting not on n-ary > > relations, however there are some other choices. I'm hoping I can get > > Pat Hayes and Richard Fikes to work with me on this one. > > An important distinction for the medical community is whether it is > > the fluent that is reified or the observation of the fluent, i.e. > > whether we have > > > > (X as observed by O at time T) is_member_of Group or > > > > X is_member_of (Group at time T) > > > > The first is the way to describe a log book of observations such as > > the medical record; the second is probably more important for models > > of language phenomena such as the classic "The King of France". > > > > The other alternative which fits closely with some indexed notions of > > parthood such as barry Smith's, is > > > > X (is_member_of at_time t) Group. > > > > but that involves reifying 'is_member_of' > > > > > > On the side of "ontology engineering": > > > > Ontology 101 tutorial specifically for OWL/RDF. > > I'd hope that some of the pizza tutorial material could get into > > this, or perhaps beside it. > > There is an interesting comparison - I am not sure it is for a best > > practice note - that the pizzas and wines require different paradigms, > > or at least different emphasis. Pizzas are primarily about > > construction - pizzas have someValuesFrom topping. Wines are > > primarily about exclusion - CarbernetSavignon is made only > > (allValuesFrom) CarbernetSauvignonGrapes. > > > > > > I think a note to help orient people on the role OWL and RDF in > > semantic integration is critical, I get pinged on that regularly. I > > lot of people think OWL is the silver bullet for semantic integration > > (I suggested at ISWC last year that semantic integration is a > > mountain, not a werewolf, and OWL is, at best, a small silver chisel). > > There was just a Dagstuhl symposium on this subject in general (i.e. > > not specific to OWL), and special issues of AI Magazine and Sigmod > > record coming out as well. I hope Natasha and/or MikeU will take the > > lead on such a note. > > > > > > People who know what "ontology" and "semantics" actually mean (in the > > much larger world outside of computer science), often ask why the two > > have become nearly synonymous on the semantic web. Personally, I > > think its a fair question and a short note on why we're so confused > > would be worthwhile. Maybe this goes in another task force (wasn't > > there a clean up the mess we've made task force?) > > > > We're open to other suggestions. > > > > -Chris (OEP co-co) > > > > Dr. Christopher A. Welty, Knowledge Structures Group > > IBM Watson Research Center, 19 Skyline Dr., Hawthorne, NY 10532 > > USA > > Voice: +1 914.784.7055, IBM T/L: 863.7055, Fax: +1 914.784.7455 > > Email: welty@watson.ibm.com, Web: > > http://www.research.ibm.com/people/w/welty/ > > > > -- > > Alan L Rector > > Professor of Medical Informatics > > Department of Computer Science > > University of Manchester > > Manchester M13 9PL, UK > > TEL: +44-161-275-6188/6149/7183 > > FAX: +44-161-275-6236/6204 > > Room: 2.88a, Kilburn Building > > email: rector@cs.man.ac.uk > > web: www.cs.man.ac.uk/mig > > www.opengalen.org > > www.clinical-escience.org > > www.co-ode.org > > -- Alan L Rector Professor of Medical Informatics Department of Computer Science University of Manchester Manchester M13 9PL, UK TEL: +44-161-275-6188/6149/7183 FAX: +44-161-275-6236/6204 Room: 2.88a, Kilburn Building email: rector@cs.man.ac.uk web: www.cs.man.ac.uk/mig www.opengalen.org www.clinical-escience.org www.co-ode.org
Received on Tuesday, 12 October 2004 09:06:48 UTC