[seek-kr-sms] OWL Inference APIs (was Re: SMS stuff)
Serguei.Krivov at uvm.edu
Thu Apr 1 07:26:46 PST 2004
Sure, if we can get the essential part of what we need just with owl ,
that would be the best option. But I thought it would be nice to have a
clear idea about availability of this option in context of the
requirements we have. We might live w/o Role boxes and feature
agreements (although they are nice) but we can not bypass the problem of
compatibility of spatial/temporal datasets.
In connection with this I wanted to ask you and Shawn- how will you
deal with spatial/temporal context of datasets in your theory of
semantic types (ref to your paper)- will be spatial/temporal context
part of semantic type or it will be handled separately as
spatial/temporal feature? For example if one wants to check hypothesis
"In all places where there are bears the species abundance is high" one
would possibly need to compare areas where bears live with datasets
related to species abundance in some areas that covers the bears area.
How we would then specify constraint that location of one dataset should
cover location of another. The attribute has location is part of
ontology (Fig 4 in your paper). Does it imply that location should be
part of semantic type????
Another point about getting away with existing reasoners: Here are
concrete domain expression which RACER supports. My understanding is
that owl does not support that( please correct me if it is wrong!). Can
we use that to specify all what we need about spatial locations???? For
rectangular regions perhaps??
(AN stands for attribute name).
(min AN integer) |
(max AN integer) |
(equal AN integer) |
(equal AN AN) |
(divisible AN cardinal) |
(not-divisible AN cardinal) |
(> aexpr aexpr) |
(>= aexpr aexpr) |
(< aexpr aexpr) |
(<= aexpr aexpr) |
(<> aexpr aexpr) |
(= aexpr aexpr) |
(string= AN string) |
(string<> AN string) |
(string= AN AN) |
(string<> AN AN)
string -> " letter* "
aexpr--> AN | real | (+ aexpr1 aexpr1 _) | aexpr1
(see pages 47 and 50+ of RACER manual)
>>Do you have plans to use existing or tweak, extend existing reasoners?
>>(we have some plans here on that too ...)
Yes we need a DL reasoner in context of IMA and in context of Integrated
History KB project we are trying to fund. In both cases support for
spatially/temporally explicit reasoning is crucial. In both cases we
would rather get away with owl and existing reasoners if we can. But at
this moment I do not know if we can and I want to know it for certain.
>>>>> "SK" == Serguei Krivov <Serguei.Krivov at uvm.edu> writes:
SK> Thanks for the interesting survey. I also have been looking at DL
SK> reasoning with focus on tableaux algorithms and found a few points
SK> of attention. Apparently there are a few semantic features which are
SK> part of present owl, but they are extremely useful and they are
SK> available in some decidable systems.
SK> 1. Role boxes: In owl one can not say that role Uncle is subrole of
SK> composition of roles Parent*Brother. Role boxes were avoided for a
SK> time since in general they lead to undecidable systems. But
SK> some limited (acyclic) role boxes can be added to SHIQ without loose
SK> 2. Feature(functional role) agreement. In owl one can not say
SK> "for every chemical flow its agent should be the same as agent of
SK> respective stocks it connect"-
SK> flow.agent=flow.source.agent=flow.target.agent. But in very old
SK> ALCF it is possible. Apparently addition of agreement/disagreement
SK> functional roles does not lead to undesirability in many even more
SK> complex cases.
SK> 3. Reasoning with concrete domain vs time and space. Reasoning about
SK> space and time may not be important for general users of ontologies
SK> it is not in owl. But it is important for ecologists and perhaps
SK> eventually we shall bump in it. Although Racer supports reasoning
SK> concrete domains such as integers and friends, it does not come to
SK> space/time. Yet potentially we can use DL reasoner for checking
SK> consistency of statements about space, time , and even space-time as
SK> long as they are represented properly (as admissible domain). I am
SK> attaching paper that surveys this topic in detail. Specifically
SK> interesting points about space and time are in the end and of course
SK> there are many references on this subject worth of reading.
SK> Certainly it is not possible to combine all semantic features we
SK> one decidable DL system. But I think it would be good to
SK> what features are the most important in context of SEEK. Then we can
SK> to design a tableaux that accommodates most of the essential
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