Very nice! On Mar 16, 2013, at 2:12 PM, Jim McCusker <mcc...@rpi.edu> wrote:
> I see Nanopublications as providing a framework for modality. They, of > course, use named graphs to do this, but they provide a way to express > attribution and justification in a consistent manner. http://nanopub.org > > > On Sat, Mar 16, 2013 at 12:59 PM, John Madden <john.mad...@duke.edu> wrote: > Medical records are filled with modal assertions: > > Possibly P(x) > I believe that P(x) > Jim believes P(x) (whereas e..g. perhaps David, Umutcan, Jeremy and I > don't). > At 5:00 pm today P(x) > I disavow P(x) > It is extremely unlikely that P(x) > I know that P(x) > I regret that P(x) > I am reponsible for bringing about P(x) (!!!!) > > and these are typically the most "interesting" (in the sense of having > practical medical consequences) statements in medical records. > > OWL logic (out-of-the-box) does not include support for modal reasoning of > arbitrary kind (and there are a countless number of kinds). Put another way, > OWL out-of-the-box has a commitment to one particular modality. So we don't > expect an OWL reasoner to reason with arbitrary modal assertions; in fact, we > don't expect the OWL language necessarily to even be competent to express > multiple, arbitrary modalities, out-of-the box. It just isn't part of the > native language. > > I agree with Jim and others that if you want to use OWL, you must let OWL be > OWL. We should reason locally with it, accepting its limitations. One such > limitation is that if you choose to reason with owl:sameAs, under OWL rules > (i.e under OWL modality), you have situated yourself within a universe, > consisting of a set of possible worlds related to each other in a particular > way (to cast it that way), in which the resources referenced really are the > same resource in all relevant respects—where "relevant" means relevant to > your considerations: considerations that are not part of OWL, but of which > OWL inference rules are perforce a subset. > > If you are in doubt whether you can buy into that, then you just shouldn't > include those particular triples—or else not use OWL (out-of-the box, or > perhaps at all) to reason. (Maybe "reason" some other way, maybe "manually" > by using your noggin while inspecting the triples or some insight-provoking > representation thereof.) Or better and in addition, you should simply > consider the result of any OWL reasoning exercise as a kind of experiment—not > "truth" simpliciter, but just a way of informing yourself about the > implications of situating yourself within some set of possible worlds under > OWL modality, given that you provisionally accept certain assertions as facts. > > In my long-held opinion, where clinical records are concerned "local" and > "(OWL-)relevant" would often mean pre-selecting a pretty darned small set of > "wild-type" triples, by which I mean triples culled from sundry sources in > the jungle of the Semantic Web: a few dozen? a few hundred? Maybe. Maybe more > or less, depending on what it is you hope to accomplish when you press the > fateful button labeled "INFER". > > Of course, it's possible to fiat-define as many modal predicates as you want, > and to use them to navigate through the jungle; but not to automagically > reason with them. Fiat predicates like <asserts> (with domain e.g. > foaf:Person and range e.g. trix:graph; thank you Jeremy) could very useful > for pre-navigating among graph fragments to select the ones with which you > care to populate your particular world(s). > > John > > On Mar 16, 2013, at 1:08 AM, Jim McCusker <mcc...@rpi.edu> wrote: > >> David, >> >> The problem with this is that by definition, URIs ALWAYS denote the same >> resource. If there is doubt that you might be denoting something other than >> what a resource is, you should be defining your own resource. >> >> Jim >> >> >> On Sat, Mar 16, 2013 at 12:35 AM, David Booth <da...@dbooth.org> wrote: >> Hi Umutcan, >> >> You have indeed stumbled on a deep question, and I think Jeremy's suggestion >> is exactly right. This paper on "Resource Identity and Semantic Extensions: >> Making Sense of Ambiguity" illustrates how owl:sameAs works in RDF semantics: >> http://dbooth.org/2010/ambiguity/paper.html#sameAs >> >> There are two keys to understanding owl:sameAs. One is to answer the >> question: what RDF graph are you considering? The other is to understand >> that the same URI may denote different things in different RDF graphs. It >> is only when RDF statements are in the *same* graph that the RDF semantics >> requires the URI to denote the same resource. That is why the question of >> what graph you are considering is crucial, and why Jeremy suggested keeping >> the different perspectives in different graphs. >> >> FYI, the above paper also explains how you can "split" the identity of an >> RDF resource if you need to merge RDF graphs that use the same URI in >> contradictory ways. >> >> David >> >> >> >> On 03/15/2013 02:29 PM, Jeremy J Carroll wrote: >> I did not find this a rookie question at all. >> >> This seems to get to the heart of some of the real difficult issues in >> Semantic Web. >> >> My perspective is different from yours, and a resource description that I >> author is a description of the resource from my perspective; a resource >> description that you author is a description from your perspective. >> >> If I have some detailed application that depends in some subtle way on my >> description, I may want to ignore your version; on the other hand, a third >> party might want to use both of our points of view. >> >> One way of tacking this problem is to have three graphs for this case: >> >> Gj, Gu, G= >> >> Gj contains triples describing my point of view >> Gu contains triples describing your point of view >> G= contains the owl:sameAs triples >> >> Then, in some application contexts, we use Gj, sometimes Gu, and sometimes >> all three. >> >> Jeremy >> >> >> >> >> On Mar 15, 2013, at 11:02 AM, Umutcan ŞİMŞEK <s.umut...@gmail.com> wrote: >> >> Thanks for the quick answer : ) >> >> So this issue is that subjective for contexts which allows to use owl:sameAs >> to link resources if they are not semantically even a little bit related in >> real world? >> >> Sorry if I'm asking too basic questions. I'm still a rookie at this :D >> >> Umutcan >> >> >> On 15-03-2013 19:38, Kingsley Idehen wrote: >> On 3/15/13 1:05 PM, Umutcan ŞİMŞEK wrote: >> My question is, does LODD use owl:sameAs properly? For instance, are those >> two resources, dbpedia:Metamizole and drugbank:DB04817 (code for >> Metamizole), really identical? Or am I getting the word "property" in the >> paper wrong? >> The question is always about: do those URIs denote the same thing? Put >> differently, do the two URIs have a common referent? >> >> ## Turtle ## >> >> <#i> owl:sameAs <#you>. >> >> ## End ## >> >> That's a relation in the form of a 3-tuple based statement that carries >> entailment consequences for a reasoner that understand the relation >> semantics. Through some "context lenses" the statement above could be >> accurate, in others totally inaccurate. >> >> Conclusion, beauty lies eternally in the eyes of the beholder :-) >> >> >> >> >> >> >> >> >> >> >> >> >> -- >> Jim McCusker >> Programmer Analyst >> Krauthammer Lab, Pathology Informatics >> Yale School of Medicine >> james.mccus...@yale.edu | (203) 785-4436 >> http://krauthammerlab.med.yale.edu >> >> PhD Student >> Tetherless World Constellation >> Rensselaer Polytechnic Institute >> mcc...@cs.rpi.edu >> http://tw.rpi.edu > > > > > -- > Jim McCusker > Programmer Analyst > Krauthammer Lab, Pathology Informatics > Yale School of Medicine > james.mccus...@yale.edu | (203) 785-4436 > http://krauthammerlab.med.yale.edu > > PhD Student > Tetherless World Constellation > Rensselaer Polytechnic Institute > mcc...@cs.rpi.edu > http://tw.rpi.edu
