semantic web

Wolf in Sheep's Clothings (Part IV)

(continued from part III)

Over the last year I had hardly time to advance my Perl client to the AllegroGraph tuple server. Which is a shame, as it is fun to take the existing REST interface and to offer it in a perlish mindset.

So when the Perl hackathon (report) was in Vienna these days, and coincidentally also the RDF Perl hackathon Geilo next week, I thought I should use the opportunity to a rub shoulders with the Perl illuminaries, at least for half a day. But when I arrived, everyone was already in deep hacking mode, so I had no excuse but to do programming myself.

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RDF::AllegroGraph::Easy Maintenance Release

When I created an experimental version of the Perl client RDF::AllegroGraph::Easy it worked against the AG server 3.1.1.

Since then some subtle changes occurred, so that I have upgraded the client to continue to work.

Franz Inc. has also provided me with a pre-release of AG 4.

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I Found(ed a) Religion!

[Beware: Topic Maps ahead.]

Once you reach a certain age, you seriously ask yourself whether this has been be all: wealth, fame and many beautiful women.

It is the time when you look for a more integrated meaning in the universe. A meaning which transcends all levels of abstraction. And a processing model which gets rid of the silly separation between programming language and semantic data store with its static knowledge.

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ESTC 2009 Impressions

Start of December I attended the ESTC 2009 (European Semantic Technologies Conference) here in Vienna.

It was my first attendence, and it was interesting to see how the non-academic faction of the semantic web crowd looked like. I had seen the academic portion at the ESWC 2009 where I presented a paper on semantic time series in one of the workshops.

And while I wore my Topic Maps T-shirt publicly in Heraklion, at the ESTC it was kept well hidden under my pullover all the time.

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The Mr. Peppers Minting PSIs

CatBert was in a very aggressive mood. He had interviewed me all day on subject identification and how it worked for the Topic Maps and the RDF stack.

But the longer he investigated, the more poignant his remarks became. This evening he even meant: Robert, I am getting tired of the lack of imagination in the semantic web community.
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Wolf in Sheep's Clothings (Part III)

I still have my eyeballs fixated on the AllegroGraph server. Since v3.2 it has a new HTTP server exposing a pretty RESTful interface (not perfect, but close) derived from Sesame.

The Python client shipped with the distribution is using it, so I wondered how this would pan out in Perl. Pan out on CPAN, so to say. Last weekend I did some tinkering and concocted a first, naive Perl client.

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Throwing off Ballast (Part I)

As my interests shift I will have to jettison a few things.

My first (innocent) victim is the Semantic Web course I gave the last years at the local Technical University.

The last iteration was definitely smoother than the one before, both in terms of content and organisation. And dealing with students was quite fun.

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CatBert on F{}OWL Ontologies (S01E02)

CatBert was sitting in front of his CatBook. He again made this hissing sound letting me know that he is onto something.

"Ok, what is it today?"
"Uhm, no. What about it?"
  • "Well, this guy is observing that many Semantic Web organisations, conferences, companies, etc. have not put their own content into RDF form.
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Wolf in Sheep's Clothings (Part II)

A while back I experimented with the Java client API of AllegroGraph to talk to a triple store.

The latest release (V3.1.1) also sports a Python client which immediately aroused my interest, and that for several reasons:

  • It is using a new HTTP protocol with the AllegroGraph server, one using JSON.
  • And its API is following that of Sesame.

The following simply goes through the basic motions, as also described by the Python tutorial.

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CatBert on F{}OWL Ontologies (Pilot)

My CatBert has become quite recalcitrant lately. From what I understood from its musings, it is all because of the bad jokes I used to crack about it. And also the cruel schroedinger'sch thought experiments I conducted.

Virtually conducted, mind you. But people never believe me anything.

After some long, heated debate I conceded CatBert to vent its anger, even publicly in this very blog. So what follows is CatBert's first public statement. Apologies for the talk-down style, but as you know: a cat is a cat is a cat.

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ESW 2008 Organisation

Einführung in Semantic Web

Code @ tuwien: 188.399 at WS 2008


Dipl.-Ing. Dr. Robert (\rho) Barta (switch the c and the dot)

<blockcode type="astma">
rho isa person,
who is-employed-at arcs,
which isa research-center
located-in austria,
! Robert Barta
! nick : rho
! academic-title : Dipl.-Ing.

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ESW 2008


  • 6.2.2009 10:56: I have just submitted the results of the exam (and the lab assignments) to the university. These will be posted at the usual place. On paper which is low-tech, but working. The results will be held back for a week or so, before they will be forwarded to the central administration.
  • 1.2.2009 16:54: Marking of exams is very cumbersome and slow. Still 4 questions are missing. Maybe some time next week.
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Wolf in Sheep's Clothings (Part I)

The other week at the Triple-I conference Andreas Blumauer mentioned to me AllegroGraph as a product which can do geospatial and temporal reasoning. I was not deterred by their criminally 90'ish web site (Update 4.4.09: there is now a new flashy design!) and downloaded their free Java edition with an upper limit of 50,000,000 triples.

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Accosted By A Barker

When you submit papers to academic conferences, then you have to be prepared that some of them will be rejected. And this is all good and well.

Now, in the years 2004 to 2006 I have submitted numerous papers to Semantic Web related conferences, such as the WWW conferences or ISWC.

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Working with Redland RDF and a DIG Reasoner

(by Lara Spendier, adaptions by rho)

RDF::Redland is the Perl wrapper around the Redland RDF libraries. With it you can read, write and query RDF graphs.

While Redland supports SPARQL to a large degree, there is no support for OWL, or any other kind of reasoning. This is where RDF::Redland::DIG kicks in: It is an extension to exchange information with a DIG reasoner, i.e.

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