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Re: [ontolog-forum] Webby objects

To: "John F. Sowa" <sowa@xxxxxxxxxxx>
Cc: "[ontolog-forum]" <ontolog-forum@xxxxxxxxxxxxxxxx>
From: Pat Hayes <phayes@xxxxxxx>
Date: Tue, 20 Nov 2012 10:15:43 -0800
Message-id: <4DE7439D-885B-49CE-9876-F017CD0E2038@xxxxxxx>
John, you clearly have an overall vision for the SWeb, a passion for promoting 
it, and energy to spare. Why then are you haranguing *us*, in *this* forum? We 
have no influence over SWeb standards. Why aren't you proposing to the W3C to 
set up a working group (or better still, setting up the group and then 
proposing to the W3C that y'all do whatever it is that you think needs to be 
done)? Just writing a W3C "note" (which has no normative content and so can be 
published fairly freely) would be a way to get things started: if enough people 
rally to your flag, you have the beginnings of a working group and a nascent 
community of users right there.     (01)

Pat    (02)

On Nov 20, 2012, at 9:35 AM, John F Sowa wrote:    (03)

> Ed, Chris, Amanda, Doug, and Rich,
> I'll start by emphasizing that I have no objection to anyone
> developing or using any tools or notations they find useful.  My
> primary objection to what became of the Semantic Web is the loss
> of most of the goals stated in Tim B-L's original DAML proposal.
> The three terms Tim emphasized were diversity, heterogeneity, and
> interoperability.  All of them disappeared from the final DAML report.
> Even tools that had been developed to use RDF and OWL, such as SWRL
> and RuleML, were omitted or deprecated.
> The letter A in DAML is for Agents.  To express messages among
> heterogeneous agents, Tim proposed SWeLL (Semantic Web Logic Language)
> as a superset of propositional, first-order, and higher-order logic.
> SWeLL required high expressive power to accommodate everything that
> could be expressed in any or all of the languages and systems cited.
> The insistence on decidability is incompatible with heterogeneity.
> But some of the most efficient implementations translate OWL to Prolog,
> which is undecidable.  Some people may claim that Prolog includes
> procedural features that are outside logic.  But there are many other
> logic-based approaches that have been ignored.  For example, see
>    http://www.hassan-ait-kaci.net/pdf/osf4sw.pdf
>    A Sorted-Graph Unification Approach to the Semantic Web
> What I am arguing *for* is the diversity that Tim emphasized and
> cited in his original proposal, the diversity among the 22 groups
> that were supposedly included in the DAML project, the wide range
> of R & D that has been done since 2005, and *most* importantly,
> seamless integration with the tools and notations of mainstream IT.
>>> Note that a procedure can be decidable for some data, but
>>> undecidable for other data.
> EB
>> Right.  So a desirable procedure should be decidable on all the data
>> it will be asked to process.  No one cares whether one can write
>> undecidable programs in the language.
> Yes, but I'd add some qualifications.  FOL has a large number of
> complexity classes, many of which can be distinguished by simple
> syntactic checks on the data and/or the axioms about the data.  Cyc,
> for example, perform such checks to see which procedure(s) to use.
> Since most systems today have multiple CPUs, some systems start
> a "horse race" among several procedures, pick the one(s) that
> finish early, and stop the others.  IBM's Watson with 2880 CPUs
> uses this approach heavily.
> EB
>> Industry has been using logics for the (b)/(c) cases for at least 25
>> years, and we now know a lot about the relationships between reasoning
>> algorithms, base theories, and decidability and computational bounding.
>> Almost all of the logics used for (b)/(c) are constrained FOLs or "not
>> FOL", and almost all of the algorithms used with these logics are
>> computationally bounded.  That is why they are commonly used in industry.
> There are many complex reasons, and they keep changing with the kinds
> of technology available.  My main point is that any one-size-fits-all
> solution is going to be wrong for many important applications.
> EB
>> The problem of not knowing the relationship between input
>> data -- the sets of valid sentences -- and the "not determinable"
>> result is what causes industry to shy away from FOL reasoners.
> DF
>> We devised a system that could guarantee that the combined algorithm
>> would produce a valid answer when that answer was needed (a variable
>> amount of time with a minimum value), but could normally calculate a
>> better answer through heuristic calculations.
> I also cite the paper by Bill Andersen et al., in which they developed
> a knowledge compiler that translates axioms expressed in CycL (a highly
> expressive superset of FOL) into Horn-clause rules for an inference
> engine and into SQL constraints for a relational DB.  That was the
> R & D that led them to found OntologyWorks (now HighFleet).  For
> discussion of that approach (and others), see page 6 of
>    http://www.jfsowa.com/pubs/fflogic.pdf
> OntologyWorks took a while to build up the business, but HighFleet
> now gets more business than they can handle.
> CMungal
>> I just want to point out that Ian Horrocks has developed reasoners
>> such as FaCT which count as application programs. His group develops
>> the HermiT and ELK reasoners which we use every day in the development
>> of the Gene Ontology (as well as numerous other biological ontologies).
> I'm glad that Ian is doing something useful. But a reasoner, by itself,
> is not an application program.
> FOL is actually easier for humans to read and write than OWL DL.
> And it can be stated in controlled NLs.  A knowledge compiler can
> translate FOL to whatever format is needed for whatever reasoning
> engine and database is used.
> AV
>> The real valuable work comes from identifying logic languages and procedures
>> that maximize expressiveness, usability, and reasoning within the domain
>> of statements and tasks the user needs. That is more complex and subtle.
>> There are lots of ways to design systems to either disallow certain
>> statements (IMHO, better done semantically than via unusably counter-
>> intuitive or restricted syntax), or decline to process certain reasoning
>> patters that have a high rabbit-hole risk, or cut out after a certain time,
>> or use other techniques to tune performance. The line between decidable and
>> undecidable systems is not a sweet spot for this.
> I very strongly agree.
> RC
>> Constraint propagation is another example of something you can't usually
>> do in a program with a tree structured design; it requires that the
>> program investigate constraint sets that are cross coupled.  Constraints
>> that are not cross coupled are not very useful
> Yes.  That is another problem with OWL.  No OWL ontology can specify
> any structure that is not tree.  You can't specify the constraints
> of a triangle or a bridge truss built up of multiple triangles.
> AV
>> ... by "a guaranteed finite-time result," I meant "a result guaranteed
>> to come with an unknown, but finite, amount of time.  That's the guarantee
>> that comes with "decidable" and is of little-to-no value in deployed
>> applications.
> Yes, indeed.  NP complete algorithms are decidable, but they can take
> more time than the age of the universe.  That's not useful.
> EB
>> John Sowa originally wrote that no user asks for decidability, users
>> always ask for more expressiveness.  I have yet to hear a user ask for
>> either.  Industry users are interested in capability and performance.
> I was quoting Bob MacGregor.  His users were familiar with DL systems,
> since PowerLOOM included a DL reasoner as one component.   But I agree
> with the final sentence.
> AV
>>> The line between decidable and undecidable systems is not
>>> a sweet spot for this.
> EB
>> But the line between DLs and FOLs *is* a sweet spot for this.
> No. The sweet spot for OWL is the subset used by GoodRelations and
> adopted by Schema.org.  They ignored all other features of OWL.
> For that subset, there are superfast algorithms that can generate
> a consistent type hierarchy (actually a lattice) automatically.
> For example, see the home page for Formal Concept Analysis (FCA):
>    http://www.upriss.org.uk/fca/fca.html
> In fact, FCA tools are also used to check an OWL hierarchy for
> consistency or even to generate the OWL hierarchy automatically.
> For details, type "FCA OWL concept" to your favorite search engine.
> DF
>> A multiple-method system is often the best performer. The overwhelming
>> majority of systems I see, read about, or hear about attempt to use a
>> single reasoning method to solving all problems. Whatever that method is,
>> it may perform well on some of the problems within the domain of use; it
>> often performs poorly on many others, or even rules out addressing them at
>> all.
> I very strongly agree.
> Recommendations:
>  1. Support the original DAML proposal for message passing in a highly
>     expressive logic among multiple heterogeneous.
>  2. Don't reject any tools or notations that anyone has found useful.
>     That includes all current SW tools.  But even more important are
>     all the legacy systems of mainstream IT and all the newly emerging
>     research projects that may become the future mainstream.
>  3. Promote R & D on simplifying the interfaces and techniques for
>     knowledge representation, acquisition, and use.  We need tools
>     with better human factors and with automatic generation of the
>     formats required for reasoning.  Better graphics, controlled
>     natural languages, FCA, and knowledge compilation are examples.
>  4. A smooth migration path from the tools and methodologies of
>     mainstream IT to the new technology is essential.  UML diagrams,
>     for example, are already integrated with mainstream IT.  They
>     can be added to the Schema.org vocabularies to support a superset
>     of what can be specified in OWL, but in a humanly readable form
>     that is already familiar to most programmers.
> Much more can be said, but this would be a good start.  It would
> support much more of Tim's original vision for the SW, and it
> would help bring ontologies into the mainstream.
> John
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