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Re: meta-information about assertions

From: Golda Velez <gv@btucson.com>
Date: Tue, 4 Mar 2008 11:06:44 -0700
To: Cristiano Longo <cristiano_longo@yahoo.it>
Cc: semantic-web@w3.org
Message-Id: <200803041106.44963.gv@btucson.com>

Hello Cristiano, all - I have question in this area

What about statements about assertions other than who is the asserter?

It seems to me that the QUADS you mean, only include an extra field of ID for 
a statement in order to address the statement itself?    It seems to me that 
it is important to be able to address a statement for many purposes, and that 
adding an asserter field as a property does not give the same functionality.  
With a statement address I can make any assertion about the original 
statement, which is much more flexible than only adding an asserter.

If we take this example again

s1 p1 01
s2 p2 o2

but add naming, maybe I use the wrong convention but say

n1: s1 p1 01
n2: s2 p2 o2

now as a third person I can add the assertion

n3: n1 p3 o4

which might have such predicate as p3 = 'ex:agrees_with_based_on'  and o4 some 
basis for agreement (or disagreement).   It seems to me this ability to talk 
about statements is really fundamental to any meaningful discussion/ building 
of knowledge other than rigid already-perfectly-agreed on facts, which are 
fewer than one might at first imagine.

Also, is it possible to construct a named graph in RDFa by simply adding an 
id= property to the tag?   I will send a separate email about this subject...

thanks

--Golda





On Tuesday 04 March 2008 8:21, Cristiano Longo wrote:
> 
> Thanks all.
> 
> Let me summarize. There is too main trends. 
> The first(Phil Archer, Story Henry) suggests to keep
> track of a "graph" and record graph provenance. If I
> understood good, it means to use QUADS or to put into
> my knowledge base only graph uri and graph provenance.
> 
> The second trend is to store assertions into rdf using
> something like realization, creating for example an
> individual assertion with an asserter and some
> property 
> filled with the assertion.
> 
> I noticed that Evaluation and Report Language, 
> Semantic Web Publishing Vocabulary(WIQA) and Ratings
> Ontology follows this second trend(probably also Proof
> Markup Language), providing properties to specify the
> asserter of something(e.g. in EARL an agent assert
> that a document passed or not a checkpoint).
> 
> So i think that probably(if not exists), for
> interoperability purposes, we need to formalize these
> situations into a main specification(or extending a
> suitable one), preferably grounding it with
> description logics.
> 
> Thank you and sorry for my english,
> Cristiano Longo 
> 
> --- Chris Bizer <chris@bizer.de> ha scritto:
> 
> > Hi Cristiano,
> > 
> > as Steffen already said, using the Named Graph data
> > model together with 
> > SPARQL is a  practical and well tested way for doing
> > this.
> > 
> > Reification is considered dead by most people
> > working on Semantic Web-based 
> > data integration. I think the only people still
> > thinking about using 
> > reification are the new OWL working group and I hope
> > that they will also 
> > realize at some point that they are running into
> > problems with this.
> > 
> > If you need a vocabulary for representing
> > meta-information about graphs, one 
> > option is to use the Semantic Web Publishing
> > vocabulary. A framework that 
> > might be interesting for you with regards to trust
> > is the WIQA Web 
> > Information Quality Assessment framework, which
> > employs the Named Graphs 
> > data model and allows you to formulate various
> > information filtering 
> > policies using a policy language that is based on
> > SPARQL.
> > 
> > See:
> > 
> > http://www4.wiwiss.fu-berlin.de/bizer/WIQA/index.htm
> >
> http://www4.wiwiss.fu-berlin.de/bizer/WIQA/browser/index.htm
> > 
> > Cheers
> > 
> > Chris
> > 
> > 
> > --
> > Chris Bizer
> > Freie Universitšt Berlin
> > +49 30 838 54057
> > chris@bizer.de
> > www.bizer.de
> > ----- Original Message ----- 
> > From: "Steffen Staab" <staab@uni-koblenz.de>
> > To: "Cristiano Longo" <cristiano_longo@yahoo.it>
> > Cc: <semantic-web@w3.org>
> > Sent: Tuesday, March 04, 2008 9:13 AM
> > Subject: Re: meta-information about assertions
> > 
> > 
> > > Hi,
> > >
> > > here is a WWW08 paper about this:
> > >
> >
> 
http://www.uni-koblenz.de/~staab/Research/Publications/2008/WWW2008-MetaKnowledge.pdf
> > > and here is its implementation:
> > >
> >
> http://www.uni-koblenz.de/FB4/Institutes/IFI/AGStaab/Research/MetaKnowledge
> > >
> > > Cheers,
> > > Steffen
> > >
> > > Cristiano Longo schrieb:
> > >> Hi all,
> > >> i'm trying to merge rdf(more specifically OWL)
> > graphs
> > >> from different sources using collaborative
> > filtering
> > >> and trust related technologies. But my question
> > is:
> > >> what is the proper way to encode a "meta
> > assertion"
> > >> like "A says X about B", in order to deal with
> > >> contraddictory assertions?
> > >>
> > >> Reification? Using SKOS? Something else?
> > >>
> > >> Thank you in advance.
> > >>
> > >>
> > >>       ___________________________________
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> > >>
> > >>
> > >>
> > > 
> > 
> > 
> 
> 
> 
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Received on Tuesday, 4 March 2008 17:57:39 UTC

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