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Re: [ontology-summit] Clarification re Big Data Challenges Synthesis

To: Ontology Summit 2012 discussion <ontology-summit@xxxxxxxxxxxxxxxx>
From: Simon Spero <sesuncedu@xxxxxxxxx>
Date: Tue, 3 Apr 2012 18:43:14 -0400
Message-id: <CADE8KM6FYPhcN3KNyNxk0U60E1FDn_NY+JfmPFVpu5qOMrDuJQ@xxxxxxxxxxxxxx>
On Tue, Apr 3, 2012 at 6:00 PM, Obrst, Leo J. <lobrst@xxxxxxxxx> wrote:
I used to consider blank nodes as just a kind of Skolemization (and one can give a blank node a name easily enough), but I've seen many different interpretations of blank nodes.

Here's a good recent paper:

Mallea, Alejandro; Marcelo Arenas; Aidan Hogan; and Axel Polleres. 2011. On Blank Nodes. ISWC 2011. http://db.ing.puc.cl/amallea/papers/mahp-iswc2011.pdf.

Pat Hayes would be the one to ask about this.

I think Pat has formally defined blank nodes as a kind of train wreck:  see/hear


 Simon

-----Original Message-----
From: ontology-summit-bounces@xxxxxxxxxxxxxxxx [mailto:ontology-summit-bounces@xxxxxxxxxxxxxxxx] On Behalf Of John F Sowa
Sent: Tuesday, April 03, 2012 5:32 PM
To: ontology-summit@xxxxxxxxxxxxxxxx
Subject: Re: [ontology-summit] Clarification re Big Data Challenges Synthesis

Amanda and Leo,

AV
> A further point: some folks (AFAICT, people who have done little work
> with FOL or HOL based systems) will argue, or simply assert, that more
> expressive languages make the representation work harder (because they
> are so complex or have harder to understand elements, like quantifiers).

Unfortunately, there is a tiny kernel of truth to that, but it's not
because of the complexity of the logic.  It's mostly a result of having
no guidance about where to start.

The more restricted languages are designed to collect a narrow range
of information, so they give users some guidance for that tiny subset.

That is one reason why I recommend a combination of diagrams with CNLs.
For example, each UML diagram is designed to capture one kind of info
in one highly restricted way.  For OWL-like stuff, the class diagrams,
Entity-Relationship diagrams, and component diagrams give you 99% of
what is contained in the published OWL ontologies.  For the more
general stuff, you can use controlled English to say anything else
that needs to be said.

As for simplicity, I was just looking at a recent W3C note that was
trying to explain the semantics of blank nodes in RDF.  The point
is absolutely trivial:

 1. A blank node represents something that is known to exist, but
    whose identity is unknown.

 2. A name can be associated with that thing for further references.

 3. The type of thing can be specified with a monadic predicate.

There is nothing more to say.  But if you type "blank nodes in RDF"
to Google, you get 16,100 documents that use the most convoluted
gobbledy-gook to explain something anyone can say in English with
the phrase "There exists something of type T, which we'll call x."
And then you can mention x when you want to add more info.

It's trivial, but these people publish papers in refereed journals
about how they "webified" logic.  It's pathetic.

Leo
> Currently we are developing an access policy model (OWL ontology
> and instances), translating these to Prolog, then translating
> the Prolog to efficient representation, i.e., by extensionalizing
> as much as possible (driving rules to ground, tabling, etc.),
> bit-encoding, etc.

For our VivoMind work, we use three languages:  Prolog for all
the advanced AI stuff; C for those algorithms that have been
thoroughly debugged, frozen, and optimized; and Java for the
user interfaces.  We also use controlled English for definitions
that are translated to Prolog and/or conceptual graphs.

We routinely translate SemWeb stuff to Prolog and get a huge
performance increase over the native SemWeb software.  But that
is partly because we have a lot of Prolog predicates that are
just calls to C subroutines.  (We tried using C++, but it just
causes bloat without much, if any reduction in programming time.)

John

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