FOAF browser

Thanks Josef, thanks Pascal! I have complained that Morten's Foaf explorer is still down, they, instead of complainig as well, pointed me to their own FOAF explorers: Josef has his Advanced FOAF Explorer, very minimalistic, but it works! And Pascal points to Martin Borho's FOAFer. FOAFer has a few nice properties.

Thank you guys, your sites are great!

Is your source code there? Because both of your tools lack a bit in looks, to be honest. And do you really think, users like to see SHA1 sums? Or error messages? (Well, actually, that was OK, that helped me discover a syntax error in the AIFB FOAF files). Please, don't misunderstand me: your site really are great. And I like to use them. But in order to reach a more general audience, we need something slicker, nicer.

Maybe a student in Karlsruhe would like to work on such a thing? Email me.

Nutkidz sind wieder da!

Auf nutkidz.de finden sich die ersten drei Folgen der nutkidz wieder online! Nach dem Angriff auf Nodix mussten die Sicherheitskopien von meinem alten Rechner im Keller geholt werden. Jetzt ist die Technik erneuert: es gibt einen nutkidz-feed, so dass man sich auch mit seinem RSS-Reader den Webcomic ins Haus holen kann! So einfach sollte jeder Webcomic zu lesen sein.

In den nächsten Tagen werden die weiteren Folgen relativ bald aufeinander kommen, ich plane auf mindestens zwei oder drei täglich.

Ach ja -- und auf nutkidz.net gibt es von jetzt an die nutkidz auch auf Englisch.

New tagline is my New Year's resolution

I just changed the tagline of this blog. The old one was rather, hmm, boring:

"Discovering the Semantic Web, Ontology Engineering and related technologies, and trying to understand these amazing ideas - and maybe sharing an idea or two... "

The new one is at the same time my new year's resolution for 2006.

"Kicking the Semantic Web's butt to reality"

'nuff said, got work to do.

Fellow bloggers

Just a few pointers to people with blogs I usually follow:

• Max Völkel, a colleague from the AIFB, soon moving to the FZI and right now visiting DERI. He obviously likes groups with acronyms. And he's a fun read.
• Valentin Zacharias, who has deeper thoughts on this whole Semantic Web stuff than most people I know, working at the FZI. He's often a thought-provoking read.
• Planet RDF. The #1 blog on news for the (S/s)emantic (W/w)eb, both with major and minor initials. That's informative.
• Nick Kings from BT exact. We are working together on the SEKT project, and he just started to blog. Welcome! A long first post. But the second leads to a great video!
• Brendan Eich, one of the Mozilla gurus. I want to know where Mozilla is headed to - so I read his musings.
• PhD. It's not a person, it's a webcomic, granted, but they offer a RSS feed for the comic. Cool. I always look forward for new episodes.

So, if you think I should read you, drop me a note. I especially like peers, meaning, people who like I do are working on the Semantic Web, maybe PhD students, and who don't know the answer to anything, but like to work on it, making the web come real.

Nacktschnecken - Soundtrack?

Heute in der Sneak gewesen im Stuttgarter Metropol - wie fast jeden Montag. In letzter Zeit kamen einige ziemlich coole Filme, die ich eigentlich kaum weiterempfehlen kann. Terkel in Trouble (Trailer auf kino-zeit.de, dänische Website zum Film), der vielleicht krasseste Film seit langem, mit soviel Menschenverachtung und Witz, dass einem South Park schon moralisch vorkommt. Oder Kiss Kiss Bang Bang - einer der besten Filme des Jahres, aber wiederum so überaus fies, dass ich mir schwertue jemanden weiterzuempfehlen. So auch heute.

Nacktschnecken ist ein österreichischer Film, und das hört man auch. Und es geht um einen Pornodreh, und was dabei alles schiefgehen kann. So, wen das nicht abgeschreckt hat, der kann reingehen.

Aber eines nervt mich echt. Weil der Film bislang ja nur in der Sneak lief (und auf einem tschechichsen Festival) finde ich im Netz keine Infos darüber, was im Soundtrack war. Ein paar Songs waren echt cool! Insbesondere der Song, den sie bei diesem Würfelspiel gespielt haben. Wie heißt der? Von wem ist der?

Letztlich: der Link von Mr Sneak ging zu kino-how.de. Hier kann man über die Sneakfilme abstimmen. Mit Gewinnspiel. Für weitere Sneakkarten.

More FOAF

Wow, I never can't get enough FOAF :) Besides my Nodix-FOAF file the AIFB Portal now also offers a FOAF export for all the people at the AIFB (using URIs for the people besides the mailbox SHA1-Sum as identifiers. Hah! FOAFers won't like that, but TimBL told us to do it this way in Galway a few weeks ago).

If you point your smushers at the FOAFs, I wonder if you can also compile the SWRC-output into it, as they use the same URI? And can you also, by adding my own FOAF from Nodix, that I am the same person? Anyone dare's to try? :)

It's a pity Morten's FOAF explorer is down, I'd really like to try it out and browse. Isn't there something similar out there?

A tidbit more on that is also posted on the AIFB blog, but from a different point of view.

Kroatiens nächsten drei WM Spiele 2006

Nachdem gestern die ziemlich sicheren Spiele aufgeschrieben wurde, hier der weitere Verlauf für Kroatien. Gewisse Diskrepanzen zur Realität können sich durch Tatsachen einstellen.

Kaiserslautern, Montag, 26. Juni, 16 Uhr, Zweite Runde: Italien gegen Kroatien

Haushoher Favorit des Spiels ist klar der mehrfache Weltmeister. Die Italien sind jedoch etwas zu leichtherzig, und Kroatien schafft es den alten Nachbar gegenüber der Adria zu besiegen. Das Spiel wird als SmartWeb Demonstrationsobjekt benutzt (erstes K.O.-Spiel in Kaiserslautern!), doch das geht unter weil es danach zu Schlägereien und Randalen kommt in verschiedenen deutschen Städten. Sehr traurig so was.

Hamburg, Freitag, 30. Juni, 20 Uhr, Viertelfinale: Kroatien gegen Frankreich

Mal wieder ein Weltmeister. Diesmal will Frankreich die Schlappe in 2002 wettmachen, doch Kroatien ist in Hochform nach den bisherigen Spielen. Doch es ist eine Wiederholung der WM 1998. Damals besiegte Kroatien im Viertelfinale den Favoriten Deutschland, und verlor dann im Halbfinale gegen den späteren Weltmeister Frankreich. So auch hier. Im Viertelfinale besiegen wir den Favoriten!

München, Mittwoch, 5. Juli, 20 Uhr, Halbfinale: Kroatien gegen Brasilien

Das wir die Brasilianer auch dummerweise jetzt schon wiedertreffen müssen! Im Finale wäre es doch viel spannender. Beide Mannschaften haben eine regelrechte Odyssee durch Deutschland hinter sich gebracht, um sich nach dem Eröffnungsspiel in Berlin hier in München wieder zu begegnen. Wer darf wieder nach Berlin? - nur, diesmal zum Finale. Am Tag zuvor konnte sich Deutschland als einer der beiden Finalteilnehmer qualifizieren - und wer wird nun den Gastgeber im Finale fordern? Alle tippen auf den Weltmeister.

Letztes Spiel wird dann entweder in Stuttgart gegen Holland um Platz Drei, oder in Berlin gegen Deutschland um den Titel. Egal wie es ausgeht: das Spiel wird am nächsten Tag Schlagzeilen machen!

Kroatiens erste drei WM Spiele 2006

Gestern wurde ich durch die Nachricht, dass die WM Gruppen ausgelost werden, eher überrascht (Dank an Rudi für den Hinweis), aber jetzt bin ich über die Ergebnisse erfreut - das werden sehr schöne Spiele!

Berlin, Dienstag, 13. Juni, 20 Uhr: Brasilien gegen Kroatien

Yeah! Das Megaspiel für Kroatien. Der amtierende Weltmeister. Der Favorit. Die Nummer 1 der Weltrangliste. Das erste Spiel auf der WM für beide Länder. Gab es schon mal ein Spiel zwischen den beiden? Nicht in einem offiziellen Turnier. Aber es gab ein Freundschaftsspiel letztes Jahr. Ergebnis? 1:1. Na, nichts ist unmöglich!

Nürnberg, Sonntag, 18. Juni, 14 Uhr: Japan gegen Kroatien

Die Japaner haben wir schon mal besiegt - nur ist das schon ein paar Jahre her, und es war knapp. Beim ersten Auftritt der Kroaten und der Japaner bei einer WM. Doch diesmal sind die Vorzeichen umgedreht. Japan ist Nummer 15 auf der Weltrangliste, Kroatien die 20. Es wird ein enges Spiel. Und - auch Japan konnte dieses Jahr beim Confederations Cup gegen Brasilien ein 2:2 rausholen, und hätte gar fast gewonnen...

Stuttgart, Donnerstag, 22. Juni, 20 Uhr: Kroatien gegen Australien

Ein Heimspiel für die Kroaten. Und in der kroatischen Mannschaft steckt nicht nur ein Australier kroatischer Herkunft. Die Australien waren ganz schön angekäst, als Australier wieder nach Kroatien zurückwanderten, weil sie dort in der Nationalmannschaft vorankommen konnten. Jetzt wird sich Australien rächen wollen. Aber in Stuttgart hat Kroatien eine große kroatische Gemeinde in der Hinterhand. Nur - wird schwerlich dieses Spiel entscheidend werden.

Eine starke Gruppe - aber es gibt ja auch keine leichten Gruppen mehr. Ein klarer Favorit. Aber es kommt auch der Zweite weiter. Noch sechs Monate, dann rollt der Ball!

Und ich interessiere mich gar nicht für Fußball.

Du nimmst meine Schnalle, ich nehm Deine...

Tja, manchmal denkt man, dass es eigentlich ganz einfach ist: ich bin mit Deiner Frau durchgebrannt, hier, nimm Du dafür meine, OK?

Zumindest dachte dass dieser Herr. Na, mal sehen, wie es ausgeht.

A blog for the AIFB

Although I blogged here about the AIFB as well - the great place I am working at - Jens Hartmann suggested to create an own, dedicated AIFB-Blog on ontoworld. It's in beta still, kind of. We hope that other AIFB-people will blog there as well, and so keep you up to date with AIFB-stuff, blog about our papers, workshops, conference attendances, break-through results, but also the great weather in Karlsruhe and stories that happened here.

So, while I will still continue to post on the Semantic Web here, the more workplace related stuff will be found there: at the new AIFB-Blog.

Der Papst ist tot, Hurra?

Die Umfrage Perspektive Deutschland, die ich ansonsten eigentlich nur empfehlen kann, weil die Fragen echt in die Tiefe gehen und die daraus generierten Reports durchaus inhaltlich bemerkenswert sind, hat mich bei der derzeit laufenden Umfrage doch irgendwie überrascht:

Frage: Wie haben die Ereignisse der letzten zwölf Monate, z.B. der Tod von Papst Johannes Paul II., ihre Meinung gegenüber der katholischen Kirche beeinflusst?

Antwortmöglichkeiten: Stark verbessert - verbessert - nicht verändert - verschlechtert - stark verschlechtert - weiß nicht

Sonst denken die von der Umfrage aber durchaus etwas nach.

Nodix schon wieder angegriffen

Nachdem die Nodix-Seiten schon vor ein paar Wochen Opfer eines Angriffs wurden, hat es uns diesmal fies erwischt. Gab es letztes Mal nur ein Defacement, wurden wir diesmal vollständig gelöscht (nur ein perl-Script wurde hochgeladen, mit spanischen Kommentaren, die, laut Übersetzung, recht fies waren. Aber unpersönlich).

Tja, das bedeutet dass, bis ich etwas Zeit finde, die Nodix-Seiten nur teilweise funktionstüchtig sind. Die DSA4 Werkzeug-Seiten sind ganz weg, ebenso Something*Positive. Nutkidz hat eine weiße Seite, nakit-arts ist halbwegs auf den Beinen, Semantic Nodix läuft großteils schon, Nodix selber ist eher schlecht als recht wieder da.

Grrr. Ich Pappnase. 1und1 hat mich noch gewarnt, und mögliche Fehlerquellen genannt, ich hatte das dummerweise ignoriert. Hat man nun davon.

Annotating axioms in OWL - Reloaded

Yesterday I sent a lengthy mail to the OWL-ED Mailinglist] about how to annotate axioms. Peter Patel-Schneider himself, first author of the OWL Semantics specification, told me in nice words that my solution sucked heavily, by pointing out that the semantics of annotations in OWL are a tiny bit different than I thought. Actually, they are not at all as I thought. So, in the evening hours, instead of packing my stuff for a trip, I tried to solve the problem anew. Let's see where the problem will be this time.

Peter, you were right, I was wrong. I took a thorough look at the Semantics, and I had to learn that my understanding of annotations was totally screwed. I thought they would be like comments in C++ or Prolog, but instead they are rather like a second ABox over (almost) the whole universe. This surprised me a lot.

But still, I am not that good at giving up, and I think my solution pretty much works syntactically. Now we need only a proper Semantics to get a few things right.

What would be the problem? Let's make an example. I need some kind of Syntax to give axioms name. I will just take Name":" Axiom. This is no proposal for the Abstract Syntax extension, this is just for now.

Axiom1: SubClassOf(Human Mortal)
Axiom2: Individual(Socrates type(Human))

Do they entail the following?

Axiom3: Individual(Scorates type(Mortal))

Well, pitily they don't. Because the Axiom3 has a name, Axiom3, that is not entailed by Axiom1 and Axiom2. Their contents would be entailed, but the name of the axiom would not.

I guess, this is the problem Peter saw. So, can we solve it?

Well, yes, we can. But it's a bit tricky.

First, we need the notion of Combined Inverse Functional Properties, CIFP. A CIFP has several dimensions. A CIFP with dimension 1 ist a normal Inverse Functional Property. A CIFP with dimension 2 over the properties R, S can be represented with the following rule: a R c, a S d, b R c, b S d -> a = b. This means, in a two dimensional space I can identify an individual with the help of two roles. More on this here: http://lists.w3.org/Archives/Public/semantic-web/2005Feb/0095.html

Second, we extend the semantics of OWL. Every axiom entails reifying annotations. This means:

SubClassOf(Human Mortal)

entails

Individual(Statement1 type(rdf:statement)
annotation(rdf:subject Human)
annotation(rdf:property owl:SubClassOf)
annotation(rdf:object Mortal))

or, in N3:

Human owl:subClassOf Mortal.

entails

Statement1 rdf:type rdf:statement.
Statement1 rdf:subject Human.
Statement1 rdf:property owl:subClassOf.
Statement1 rdf:object Mortal.
rdf:subject rdf:type owl:AnnotationProperty.
rdf:predicate rdf:type owl:AnnotationProperty.
rdf:object rdf:type owl:AnnotationProperty.

Third, we have to state that we have a 3D-CIFP for statements over rdf:subject, rdf:property and rdf:object*. This is to ensure that Statement1 always maps to the same element in the universe, even though an OWL API could give it a blank node, or a different URI everytime (mind you, I am not suggesting to extend the OWL language with CIFPs, I just say that it is used here in order to state that all triples with the same subject, object and predicate actually is the same triple).

Fourth, the above statement also entails

Individual(Axiom1 type(owl11:axiom)
annotation(owl11:consistsOf Statement1))

or, in N3:

Axiom1 rdf:type owl11:axiom.
Axiom1 owl11:consistsOf Statement1.
owl11:consistsOf rdf:type owl:AnnotationProperty.

Fifth, owl11:consistsOf needs to be an n-dimensional CIFP with n being the number of triples the original axiom got translated to (in this case, happy us!, n=1).

This assures that an axiom is always the same, whatever it's name is, as long as it expresses the same thing. Thus, in our example, Axiom3 would indeed be entailed by Axiom1 and Axiom2. So, even if two editors load an ontology an annotate an axiom, they could later interchange and find each others annotation attached to the correct axiom.

This is only a rough sketch of the way, and yes, I see that the Interpretation gets filled up with a lot of annotations, but I still think that this is quite easy to implement, actually. Both the OWL API by Bechhofer and Volz and the KAON2 API by Motik offer access to axioms on an ontology level, and also offer the possibility to check if they are the same anyway, if I remember correctly (which is basically a shortcut for the whole semantic entailment and CIFP-stuff proposed earlier). All they need is a further field containing the URI of the axiom.

As said, this looks far more nasty than it actually is, and for most practical reasons it won't do much harm. Now we finally can annotate axioms, yeeeha!

Merrily awaiting Peter to acknowledge that this is a brilliant solution :) Or else tell me I did it all wrong again, so that I have to think over the weekend how to solve this problem again.

Cheers, denny

 *What I mean with that is the following rule: a=b :- a rdf:subject s, a rdf:property p, a rdf:object o, b rdf:subject s, b rdf:property p, b rdf:object o

Annotating axioms in OWL

This was sent to the OWLED-List by me, that prepares to come up with an OWL 1.1 recommendation. The week before, Alan Rector suggested to add the possibility to annotate axioms in OWL, which is currently not possible. There is many a good use for that, like provenance, trust, and son on. But the discussion wasn't too fruitful, so I suggested the following solution.

After it came up in discussion last week, I hoped an elegant solution for annotating axioms would arise. Pitily, no one had a brilliant idea, so I went ahead and tackled the problem in my mediocre way.

First, what do I want to achieve with my solution:

1. Don't crack the Semantic Web stack. The solution has to be compatible to XML, RDF and OWL. I don't want to separate OWL from RDF, but to offer a solution that is able to be handled by both.
2. We want to annotate not just entities, but also axioms. Thus an axiom needs to be able to be a subject in a statement. Thus an axiom needs to have an URI.
3. The solution must be easy to implement, or either people will get my FOAF-file and see whom I care about and hurt them.

Did I miss something? I found two solutions for this problem.

A) Define the relationship between an ontology (which does have an URI) and the axioms stated inside. Then we can talk about the ontologies, annotate those, add provenance information, etc. Problem: after importing axioms from one ontology into another, those information is lost. We would need a whole infrastructre for Networked Ontologies to achieve that, which is a major and worthy task. With this solution, you can annotate a single axiom by putting it alone into an ontology, and claim that when annotating the ontology you actually annotate the axiom as well. Not my favourite solution, because of several drawbacks which I won't dwell in deeper if not asked.

B) The other solution is using Reification (stop yelling and moaning right now!). I'm serious. And it's not that hard, really. First, the OWL specification offers a standard of how to translate the Axioms into triples. Second, thte RDF specification offers a standard way to reify a triple. With the RDF reification we can give a triple a name. Then we can introduce a new resource type owl11:axiom, where its instances contains the triples that were translated from a certain DL Axiom. This rdf resource of type owl11:axiom is then the name/URI of the original DL Axiom.

RDF-triples that have a subject of type rdf:statement or owl11:axiom don't have semantics with regards to OWL DLs Model Theoretic Semantics, they are just syntactic parts of the ontology in order to allow the naming of axioms in order to annotate them.

For example, we say that all Humans are Mortal. In Abstract Syntax this is

SubClassOf(Human Mortal)

In RDF triples (N3) this is:

:Human rdfs:subClassOf :Mortal.

Now reifiying this we add the triples:

:statement1 rdf:type rdf:statement.
:statement1 rdf:hasSubject :Human.
:statement1 rdf:hasPredicate owl:subClassOf.
:statement1 rdf:hasObject :Mortal.
:axiom1 owl11:consistsOf :statement1.

Now we can make annotations:

:axiom1 :bestBefore "24/12/2011"^xsd:date.
:axiom1 :utteredBy :Aristotle.

Naturally, :bestBefore and :utteredBy have to be Annotation Properties. When an axiom is broken up in more than one triple, the reasone of having an extra owl11:axiom instead of simply using rdf:statement should become clear.

Does this solution fulfill the given conditions?

1. The Semantic Web stack is safe and whole. RDF Semantics is adhered to, and OWL semantics is fine, and all syntax regulations imposed by XML and RDF/XML are regarded. Everything is fine.
2. Yep, we can annotate single axioms. Axioms have URIs. We can annotate our metadata! Yeah!
3. Is it easy to implement? I think it is: for reading OWL ontologies, a tool may just ignore all those extra triples (it can easily filter them out), and still remain faithful to the standard semantics. Tools that allow to name axioms (or annotate them) and want to deal with those, have to simply check for the correct reification (RDF toolkits should provide these anyway), and get the axiom's URI.

Problems that I see: I identified two problems. First, what happens, if those triples get separated from the other actual axiom triples? What if they get ripped apart and mushed into another ontology? Well, that problem is somewhat open for OWL DL and Lite anyway, since not all axioms map to single triples. The answer probably is, that reification would fail in that case. Strict reading could be that the ontology leaves OWL DL then and moves to OWL full, but I wouldn't require that.

Second problem, and this is by far more serious, is that people can't stand reification in RDF, that they simply hate it and that alone for that they will ignore this solution. I can only answer that reification in practise is probably much easier than expected when done properly, due to some short-hand notations available in RDF/XML-serialization, and other syntaxes. No one holds us back from changing the Abstract Syntax and the OWL XML Presentation Syntax appropriately in order to name axioms far more easy than in the proposed RDF/XML-Syntax. Serializations in RDF/XML-Syntax may get yucky, and the RDF graph of an OWL ontology could become cluttered, but then, so what? RDF/XML isn't read by anyone anyway, is it? And one can remove all those extra triples (and then the annotations) automatically if wished, without changing the Semantics of the ontology.

So, any comments on why this is bad? (Actually, I honestly think this is a practicable solution, though not elegant. I already see the 2007 ISWC best paper award, "On the Properties of Higher Order Logics in OWL"...)

I hope you won't kill me too hard for this solution :) And I need to change my FOAF-file now, in order to protect my friends...

Job at the AIFB

Are you interested in the Semantic Web? (Well, probably yes or else you wouldn't read this). Do you want to work at the AIFB, the so called Semantic Web Machine? (It was Sean Bechhofer who gave us this name, at the ISWC 2005) Maybe this is your chance...

Well, if you ask me, this is the best place to work. The offices are nice, the colleagues are great, our impact is remarkable - oh well, it's loads of fun to work here, really.

We are looking for a person to work on KAON2 especially, which is a main building block of many a AIFB software, as for example my own OWL Tools, and some European Projects. Mind you, this is no easy job. But if you finished your Diploma, Master or your PhD, know a lot about efficient reasoning, and have quite some programming skills, peek at the official job offer (also available in German).

Do you dare?

Semantic Web Gender Issue

Well, at least they went quite a way. With Google Base one can create new types of entities, entities themselves, and search for them. I am not too sure about the User Interface yet, but it's surely one of the best actually running onbig amounts of data. Nice query refinement, really.

But heck, there's one thing that scares me off. I was looking today for all the people interested in the Semantic Web, and there are already some in. And you can filter them by gender. I was just gently surprised about the choices I was offered when I wanted to filter them by gender...

Hier fehlt noch ein Bild.

Oh come on, Google. I know there are not that many girls in computer science, but really, it's not that bad!

What is a good ontology?

You know? Go ahead, tell me!

I really want to know what you think a good ontology is. And I will make it the topic of my PhD: Ontology Evaluation. But I want you to tell me. And I am not the only one who wants to know. That's why Mari Carmen, Aldo, York and I have submitted a proposal for a workshop on Ontology Evaluation, and happily it got accepted. Now we can officially ask the whole world to write a paper on that issue and send it to us.

The EON2006 Workshop on Evaluation of Ontologies for the Web - 4th International EON Workshop (that's the official title) is co-located with the prestigous WWW2006 conference in Ediburgh, UK. We also were very happy that so many reknown experts accepted our invitation to the program committee, thus ensuring a high quality of reviews for the submissions. The deadline is almost two months away: January 10th, 2006. So you have plenty of time to write that mind-busting phantastic paper on Ontology Evaluation until then! Get all the details on the Workshop website http://km.aifb.uni-karlsruhe.de/ws/eon2006.

I really hope to see some of you in Edinburgh next May, and I am looking for lively discussions about what makes an ontology a good ontology (by the way, if you plan to submit something - I would love to get a short notification, that would really be great. But it is by no means requested. It's just so that we can plan a bit better).

Regenbogen

Ich bin gerade in Galway, und hier regnet es ständig. Wirklich. Zwar meist nur kurz, aber doch halt immer wieder neu.

Dafür wurde ich heute mit einem schier unglaublichen Regenbogen belohnt: er ging wirklich über den ganzen Horizont, ein vollständiger Bogen! So was habe ich noch nie gesehen. Das Bild ist untertrieben, deutlich, in Wirklichkeit schien er noch viel heller.

Besonders spannend war, dass er kaum zwei-, dreihundert Meter entfernt aus dem Wasser zu steigen schien. Nicht irgendwo weit weg, er war direkt da - man kann sogar die Häuser durch den Regenbogen hindurch auf dem Bild sehen, der Regenbogen war vor den Häusern. So etwas habe ich noch nie zuvor gesehen. Wahnsinnig beeindruckend.

Ich hoffe, dass ich bald noch ein paar bessere Bilder bekomme.

Hier fehlt noch ein Bild.

ISWC impressions

The ISWC 2005 is over, but I'm still in Galway, hanging around at the OWL Experiences and Direction Workshop. The ISWC was a great conference, really! Met so many people from the Summer School again, heard a surprisingly number of interesting talks (there are some conferences, where one boring talk follows the other, that's definitively different here) and got some great feedback on some work we're doing here in Karlsruhe.

Boris Motik won the Best Paper Award of the ISWC, for his work on the properties of meta-modeling. Great paper and great work! Congratulations to him, and also to Peter Mika, though I have still to read his paper to form my own opinion.

I will follow up on some of the topics from the ISWC and the OWLED workshop, but here's my quick, first wrap-up: great conference! Only the weather was pitily as bad as expected. Who decided on Ireland in November?

KAON2 and Protégé

KAON2 is the Karlsruhe Ontology infrastructure. It is an industry strength reasoner for OWL ontologies, pretty fast and comparable to reasoners like Fact and Racer, who gained from years of development. Since a few days KAON2 also implements the DIG Interface! Yeah, now you can use it with your tools! Go and grab KAON2 and get a feeling for how good it fulfills your needs.

Here's a step to step description of how you can use KAON2 with Protégé (other DIG based tools should be pretty the same). Get the KAON2 package, unpack it and then go to the folder with the kaon2.jar file in it. This is the Java library that does all the magic.

Be sure to have Java 5 installed and in your path. No, Java 1.4 won't do it, KAON2 builds heavily on some of the very nice Java 5 features.

You can start KAON2 now with the following command:

java -cp kaon2.jar org.semanticweb.kaon2.server.ServerMain -registry -rmi -ontologies server_root -dig -digport 8088

Quite lengthy, I know. You will probably want to stuff this into a shell-script or batch-file so you can start your KAON2 reasoner with a simple doubleclick.

The last argument - 8088 in our example - is the port of the DIG service. Fire up your Protege with the OWL plugin, and check in the OWL menu the preferences window. The reasoner URL will tell you where Protege looks for a reasoner - with the above DIG port it should be http://localhost:8088. If you chose another port, be sure to enter the correct address here.

Now you can use the consistency checks and automatic classification and all this as provided by Protege (or any other Ontology Engineering tool featuring the DIG interface). Protégé tells you also the time your reasoner took for its tasks - compare it with Racer and Fact, if you like. I'd be interested in your findings!

But don't forget - this is the very first release of the DIG interface. If you find any bugs, say so! They must be squeezed! And don't forget: KAON2 is quite different than your usual tableaux reasoner, and so some questions are simply not possible. But the restrictions shouldn't be too severe. If you want more information, go to the KAON2 web site and check the references.