Guter Preis

Ich kann mir nicht vorstellen, dass das der Microsoft-Preis ist. Oder werden da Hunde bevorzugt? Müssen Hunde auch der Lizenz vor Öffnen der Packung zustimmen?

Hier fehlt noch ein Bild.

Noch ein Test

So, ein weiterer Test, wie gut ich von meinem Handy aus bloggen kann. Schon spannend: als ich mit Nodix anfing, habe ich die Einträge per Hand in HTML geschrieben, dann kam ein selbst programmiertes Tool in Delphi, dann Python, welches ich in einer späteren Version auch von anderen PCs verwenden konnte. Schließlich übernahm Blogger den Blog, und dank der standardisierten Schnittstellen kann ich jetzt auch direkt von meinem Handy aus Einträge erstellen. Ob mit - wie gestern - oder ohne Photo.

Ich habe bloß noch keine Ahnung, wie das mit dem verlinken funktioniert. Vielleicht einfach so: <a href="http://notausgang.baumgarf.de">geht auf diesen tollen Blog!</a> Gleich mal ausprobieren.

Update:(Test doppelt misslungen. Der Post landete zunächst auf dem falschen Blog, Semantic Nodix, und das mit dem verlinken hat auch nicht funktioniert. Menno)

Failed test

Testing my mobile blogging thingie (and it failed, should have gone to the other blog). Sorry for the German noise.

Preisuhr

Dies ist ein weiterer Test, ob meine Moblog-Einstellungen funktionieren. Das Bild ist mit meinem Handy aufgenommen und direkt von da an mein Blog geschickt. Cool, ne'?

Hier fehlt noch ein Bild.

Sacre Coeur

Ich teste nur flickr aus. Angeblich kann flickr direkt auf meinen Blog posten. Und das Bild ist wirklich schön. Aber nicht von mir.

Update: Bild ist nunmehr gesperrt. Es handelte sich um dieses Bild der Kirche Sacre Ceour in Paris, doch es scheint nun auch von flickr entfernt worden zu sein

Gotta love it

Don't do research if you don't really love it. Financially, it's desastrous. It's the "worst pay for the investment", according to CNN.

Good thing I love it. And good thing Google loves the Semantic Web as well. Or why else do they make my desktop more and more semantic? I just installed the Desktop2 Beta - and it is pretty cool. And it's wide open to Semantic Stuff.

FOAFing around

I tried to create FOAF-files out of the ontology we created during the Summer School for the Semantic Web. It wasn't that hard, really: with our ontology I have enough data to create some FOAF-skeletons, so I looked into the FOAF-specification and started working on it.

<foaf:person about="#gosia">
  <foaf:knows resource="#anne" />
  <foaf:name datatype="http://www.w3.org/2001/XMLSchema#string">Gosia Mochol</foaf:name>
</foaf:person>
<rdf:description about="#anne">
  <rdfs:isdefinedby resource="http://semantic.nodix.net/sssw05/anne.rdf" />
...

Well, every one of us gets his own FOAF-file, where one can find more data about the person. Some foaf:knows-relations have been created automatically for the people who worked together in a miniproject. I didn't want to assume too much else.

The code up there is valid FOAF as much as I can tell. But all the (surprisingly sparse) tools could not cope with it, due to different reasons. One complained about the datatype-declaration in the foaf:name and then ignored the name at all. Most tools didn't know that rdfs:isDefinedBy is a subproperty of rdfs:seeAlso, and thus were not able to link the FOAF-files. And most tools were obviously surprised that I gave the persons URIs instead of using the IFP over the sha1-sum of their e-Mails. The advantage of having URIs is that we can use those URIs to tag pictures or to keep track of each other publications, after the basic stuff has been settled.

Pitily, the basic stuff is not settled. To me it seems, that the whole FOAF stuff, although being called the most widespread use of the Semantic Web, is still in its infancy. The tools hardly collaborate, they don't care too hard about the specs, and there seems no easy way to browse around (Mortens explorer was down at the time when I created the FOAFs, which was frustrating, but now it works: take a look at the created FOAF files, entering with my generated FOAF file or the one for Enrico Motta). Maybe I just screwed it all up when generating the FOAF-files in the first run, but I don't think so really...

Guess someone needs to create some basic working toolset for FOAF. Does anyone need requirements?

SSSW Last Day

The Summer School on Ontological Engineering and the Semantic Web finished on Saturday, July 16th, and I can't remember having a more intense and packed week in years. I really enjoyed it - the tutorials, the invited talks, the workshops, the social events, the mini project - all of it was awesome. It's a pity that it's all over now.

Today, besides the farewells and thank yous and the party in Madrid with maybe half of the people, also saw the presentation of the mini projects. The mini projects where somewhat similar to the The Semantic Web In One Day we had last year - but without a real implementation. Groups of four or five people had to create a Semantic Web solution in only six hours (well, at least conceptually).

The results were interesting. All of them were well done and highlighted some promising use cases for the Semantic Web, where data integration will play an important role: going out in the evening, travelling, dating. I'd rather not consider too deeply if computer scientists are rather attacking an own itch here ;) I really enjoyed the Peer2Peer theater, where messages wandered through the whole class room in order to visualize the system. This was fun.

Our own mini project modelled the Summer School and the projects itself, capturing knowledge about the buildup of the groups and classifying them. We had to use not only quite complex OWL constructs, but also SWRL-rules - and we still had problems expressing a quite simple set of rules. Right now we are trying to write these experiences down in a paper, I will inform you here as soon as it is ready. Our legendary eternal struggle at the boundaries of sanity and Semantic Web technologies seemed to be impressive enough to have earned us a cool price. A clock.

Thanks to all organizers, tutors and invited speakers of the Summer School, thanks to all the students as well, for making it such a great week. Loved it, really. I hope to stay in touch with all of you and see you at some conference pretty soon!

Lucky Luke gegen die Daltons

Wie meistens montags, auch gestern in der Sneak gewesen. In letzter Zeit gab es - wie man im Notausgang-Blog oder auf nakit-arts mitbekommen konnte - einige echt geniale Filme: 11:14, Mr and Mrs Smith, L.A. Crash, The Fantastic Four, Nicotina, Antikörper, Madagascar, Hitchhikers Guide through the Galaxy oder Garden State. Gestern war der Film nicht ganz so gut.

Genau genommen war er grottig. Ich schreibe ja schon länger keine Filmrezis mehr, weil die Filmrezis auf Baumgarf deutlich besser sind. Ja, klar, ich stimme ihm nicht immer zu, aber meistens. So auch bei den Daltons. Einen so schlechten Film habe ich sehr selten - vielleicht noch nie - gesehen. Auf imdb gibt es eine Rezi mit dem Titel "Not ENTIRELY bad", wobei ich ein Wort aus der Überschrift streichen würde (und es ist nicht das großgeschriebene). Ansonsten sind die Meinungen auf imdb über den Film sehr deutlich: 40% haben dem Film die schlechtesmögliche Note gegeben. Reicht nicht, um den Film in Top 100 der schlechtesten Filme zu katapultieren, überraschenderweise. Ich kenne davon - soweit ich mich erinnere - aber nur einen Film, Alone in the Dark (ich weiß nicht mehr, welche Police Academy-Teile ich gesehen habe). Ob der wirklich schlechter ist? Müsste ich nochmals sehen, um das zu beurteilen. Sprich, ich werde es nie, nie, nie erfahren...

Warum sind die Daltons so grottig schlecht? Erstens, wie bei Clever & Smart schon, hat irgendjemand den Darstellern gesagt: hey, das ist eine Comicverfilmung. Also müsst ihr alle wie doof rumhüpfen und euch seltsam bewegen. Zweitens, wozu Gags? Die Vorlage hat doch schon genug davon. Drittens, die beiden Szenen, die ausnahmsweise gute sind, also die, wo Lucky Luke Joe Dalton das Serum verabreicht und wo Joe Dalton die Gulch Bank für den finalen Überfall betritt, zeigen, dass die Leute es offenbar besser draufhaben. Warum also machen sie es nicht?

Das, was ich wirklich schade finde, sind, dass 27 Millionen Dollar reingeflossen sind und hunderte von Menschen mitgewirkt haben. Muss dann das Ergebnis nicht wie Verrat vorkommen? Oder glauben diese Leute wirklich, dass sie einen guten Film gemacht haben? Darf oder muss man mit ihnen Mitleid haben? Die glauben doch an ihre Arbeit. Wie also kann so ein Murks überhaupt entstehen?

Dafür immerhin einen Narnia-Trailer (hier ist die deutsche Version verlinkt) gesehen. Auf französisch. Sah sehr vielversprechend aus. Endlich darf auch Disney ein Fantasy-Meisterwerk verfilmen, nachdem Tolkien das für den Herrn der Ringe ja testamentarisch ausgeschlossen hatte.

SSSW Day 5

Today (which is July 15th) just one talk. The rest of the day - beside the big dinner (oh well, yes, there was a phantastic dinner speech performed by Aldo Gangemi and prepared by Enrico and Asun if I understood it correctly, which was hilariously funny) and the disco - was available for work on the mini projects. But more about the mini projects in the next blog.

The talk was given by University of Manchester's Carol Goble (I like that website. It starts with the sentence "This web page is undergoing a major overhaul, and about time. This picture is 10 years old. the most recent ones are far too depressing to put on a web site." How many professors did you have that would have done this?). She gave a fun and nevertheless insightful talk about the Semantic Web and the Grid, describing the relationship between the two as a very long engagement. The grid is the old, grudgy, hard working groom, the Semantic Web the bride, being aesthetically pleasing and beautiful.

What is getting gridders excited? Flexible and extensible schemata, data fusion and reasoning. Sounds familiar? Yes, these are exactly the main features of Semantic Web technologies! The grid is not about accessing big computers (as most people think in the US, but they are a bit behind on this as well), it is about knowledge communities. But one thing is definitively lacking: scalability, people, scalability. They went to test a few Semantic Web technologies with a little data - 18 million triples. Every tool broke. The scalability lacks, even thought the ideas are great.

John Domingue pointed out, that scalability is not that much of a problem as it seems, because the TBoxes, where the actual reasoning will happen, will always remain relatively small. And the scalability issue with the ABoxes can be solved with classic database technology.

The grid offers real applications, real users, real problems. The Semantic Web offers a lot of solutions and discussions about the best solution - but lack surprisingly often an actual problem. So it is obvious that the two fit together very nicely. At the end, Carole described them as engaged, but not married yet.

At the end she quotes Trotsky: "Revolution is only possible when it becomes inevitable" (well, at least she claims it's Trosky, Google claims its Carole Goble, maybe someone has a source? - Wikiquote doesn't have it yet). The quote is in line with almost all speakers: the Semantic Web is not Revolution, it is Evolution, an extension of the current web.

Thanks for the talk, Carole!

Wikimania is coming

Wikimania starts on Friday. Looking forward to it, I'll be there with a collegue and we will present a paper on Wikipedia and the Semantic Web - The Missing Links on Friday. Should you be in Frankfurt, don't miss it!

Here's the abstract: "Wikipedia is the biggest collaboratively created source of encyclopaedic knowledge. Growing beyond the borders of any traditional encyclopaedia, it is facing new problems of knowledge management: The current excessive usage of article lists and categories witnesses the fact that 19th century content organization technologies like inter-article references and indices are no longer sufficient for today's needs.

Rather, it is necessary to allow knowledge processing in a computer assisted way, for example to intelligently query the knowledge base. To this end, we propose the introduction of typed links as an extremely simple and unintrusive way for rendering large parts of Wikipedia machine readable. We provide a detailed plan on how to achieve this goal in a way that hardly impacts usability and performance, propose an implementation plan, and discuss possible difficulties on Wikipedia's way to the semantic future of the World Wide Web. The possible gains of this endeavour are huge; we sketch them by considering some immediate applications that semantic technologies can provide to enhance browsing, searching, and editing Wikipedia."

Basically we suggest to introduce typed links to the Wikipedia, and an RDF-export of the articles annotated with these typed links being regarded as relations. And suddenly, you get the a huge ontology, created by thousands and thousands of editors, queryable and usable, a really big starting block and incubator for Semantic Web technologies - and all this, still scalable!

If the Wikipedia community agrees that this is a nice idea, which I hope with all my heart. We'll see this weekend.

SSSW Day 4

This day no theoretical talks, but instead two invited speakers - and much social programme, with a lunch at a swimming pool and a dinner in Segovia. Segovia is a beautiful town, with a huge, real, still standing roman aqueduct. Stunning. And there I ate the best pork ever! The aqueduct survived the huge earthquake of Lisbon of 1755, although houses around it crumbled and broke. This is, because it is built without any mortar - just stone over stone. So the stones could swing and move slightly, and the construction survived.
Made me think of loosely coupled systems. I probably had too much computer science the last few days.

The talks were very different today: first was Mike Woolridge of the University of Liverpool. He talked about Multiagent Systems in the past, the present and the future. He identified five trends in computing: Ubiquity, Interconnection, Intelligence, Delegation and Human-orientation.
His view on intelligence was very interesting: it is about the complexity of tasks that we are able to automate and delegate to computers. He quoted John Alan Robertson - the guy who invented resolution calculus, a professor of philosophy - as exclaiming "This is Artificial Intelligence!", when he saw a presentation of the FORTRAN compiler at a conference. I guess the point was, don't mind about becoming as intelligent as humans, just mind at getting closer.
"The fact that humans were in control of cars - our grandchildren will be quite uncomfortable with this idea."

The second talk was returning to the Semantic Web in a very pragmatic way: how to make money with it? Richard Benjamins of iSOCO just flew in from Amsterdam where he was at the SEKT meeting, and he brought promising news about the developing market for Semantic Web technologies. Mike Woolridge was criticizing Richard's optimistic projections and noted that he also, about ten years ago, spent a lot of energy and money into the growing Multiagent market - and lost most of it. It was an interesting discussion - Richard being the believer, Mike the sceptic, and a lot of young people betting a few years worth of life on the ideas presented by the first one...

Theodor W. Adorno

Hier mein Beitrag zur neuen Pro7-Show die 100 beliebtesten Aphorismen von Theodor W. Adorno (oder so ähnlich - moderiert das eigentlich Oliver Pocher oder Sonya Kraus?)

"Bei vielen Menschen ist es bereits eine Unverschämtheit, wenn sie Ich sagen"

SSSW Day 3

Yeah, sure, the Summer School for the Semantic Web is over for quite a while now, and here I started to blog about it daily, and didn't manage to get over the first three days. Let's face it: it was too much! The program was so dense, the social events so enjoyable, I couldn't even spare half an hour a day to continue the blogging. Now I want to recap some of my notes and memories I have of the second half of the Summer School. My bad memory be damned - if you want to correct something feel free to do so.

This day's invited speaker was Roberto Basili of the University of Rome. He sketched the huge field of natural language processing, and although he illustrated the possible interactions between lexical knowledge bases and ontologies, he nevertheless made a strong distinction between these two. Words are not concepts. "The name should have no value for defining a concept." This is like "Don't look into URIs" for HLT-people. He made a very interesting point: abductions will become very important in the Semantic Web, as they model human thinking patterns much closer than strict deduction does. Up until this day I was quite against abductions, I discussed this issue very stubbornly in Granada. But Roberto made me aware of a slightly different viewpoint: just sell abductive resolutions as suggestions, as proposals to the user - et voilà, the world is a better place! I will have to think abou this a bit more some day, but he did made me think.

The theoretical sessions and workshops today were packed and strenuos: we jumped from annotations to Semantic Web Services and back again. Fabio Ciravegna of the University of Sheffield's NLP-Group, who created tools like Armadillo and GATE, gave us a thorough introduction to annotations for the Semantic Web and the usage of Human Language Technologies in order to enhance this task. He admitted that many of the tools are still quite unhandy, but he tried to make a point by saying: "No one writes HTML today anymore with a text editor like Emacs or Notepad... or do you?"
All students raised their hands. Yes, we do! "Well, in the real world at least they don't..."

He also made some critical comments on the developments of the Semantic Web: the technologies being developed right now allow for a today unknown ability of collecting and combining data. Does this mean, our technologies actually require a better world? One with no secrets, privacy and spam, because there is no need for such ideas? Is metadata just adding hay to the haystak instead of really finding the needle?

John Domingue's Talk on Semantic Web (Web) Services was a deep and profound introduction to the field, and especially to the IRS system developed by the KMi at Open University. He was defending WSMO valiantly, but due to time constraints pitily skipped the comparison with OWL-S. But he motivated the need for Semantic Web Services and sketched a possible solution.

The day ended in Cercedilla, where we besieged a local disco. I guess the people were hiding, "watch it, them nerds are coming!" ;) The music surprisingly old - they had those funny vinyl albums - but heck, Frank Sinatra is never outdated. But the 80s certainly are...

SSSW Day 2

Natasha Noy gave the first talk today, providing a general overview on Mapping and Alignment algorithms and tools. Even though I was not too interested in the topic, she really caught my interest with a good and clean and structured talk. Thank for that! After, Steffen Staab continued, elaborating on the QOM approach to ontology mapping, having some really funny slides, but, as this work was mostly developed in Karlsruhe I already knew it. I liked his appeal for more tools that are just downloadable and usable, without having to fight for hours or days just to create the right environment for them. I totally agree on that!

The last talk of the day was from Aldo Gangemi on Ontology Evaluation. As I consider making this the theme of my PhD-thesis - well, I am almost decided on that - I was really looking forward to his talk. Although it was partially hard to follow, because he covered quite a broad approach to this topic, there have been numerous interesting ideas and a nice bibliography. Much to work on. I especially didn't yet see the structural measures he presented applied to the Semantic Web. Not knowing any literature on them, I am still afraid, that they actually fail [SSSW Day 1|Frank's requirements from yesterday]]: not just to be taken from graph theory, but rather to have the full implications of the Semantic Web paradigm been applied to them and thought through. Well, if no one did that yet, there's some obvious work left for me ;)

The hands-on-sessions today were quite stressy, but nevertheless interesting. First, we had to powerconstruct ontologies about different domains of traveling: little groups of four persons working on a flight agency ontology, a car rental service ontology and a hotel ontology. Afterwards, we had to integrate them. Each exercise had to be done in half a hour. We pretty much failed miserably in both, but we surely encountered many problems - which was the actual goal: in OWL DL you can't even concatenate strings. How much data intefration can you do then?

The second hands-on-session was on evaluationg three ontologies. It was quite interesting, although I really think that many of these things can happen automatically (I will work on this in the next two weeks, I hope). But the discussion afterwards was quite revealing, as it showed how differently people think about some quite fundamental issues, the importance they give to structural measures compared to the functional ones. Or, differently said: the question is, is a crappy ontology on a given domain better than a good ontology that doesn't cover your domain of interest? (The question sounds strange to you? To me as well, but well...)

Pitily I had to miss today's social special event, a football match between the students of the Summer School. Instead I had a very interesting chat with a colleague from the UPM, who came here for a talk, and who also wants to make her PhD in Ontology Evaluation, Mari Carmen Suárez de Figueroa. Interesting times are lying ahead.

SSSW Day 1

Today's invited speaker was Frank von Harmelen, co-editor of the OWL standard and author of the Semantic Web Primer. His talk was on fundamental research challenges generated by the Semantic Web (or: two dozen Ph.D. topics in a single talk). He had the idea after he was asked one day in the cafeteria "Hey Frank, whazzup in the Semantic Web?"

In the tradition of Immanuel Kant's four famous questions on philosophy, Frank posed the four big research challenges:

• Where does the metadata come from?
• Where do the ontologies come form?
• What to do with the many different ontologies?
• Where's the Web in the Semantic Web?

He derived many research questions that arise when you bring results from other fields (like databases, natural language, machine learning, information retrieval or knowledge engineering) to the Semantic Web and not just change the buzzwords, but take the implications that come along with the Semantic Web seriously.

Some more notes:

• What is the semantic equivalent to a 404? How should a reasoner handle the lack of referential integrity?
• Inference can be cheaper than lookup on the web.
• Today OWL lite would probably have become more like OWL DLP, but they didn't know better than

The other talks were given by Asun Gómez-Pérez on Ontological Engineering, and Sean Bechhofer on Knowledge Representation Languages for the SemWeb, pretty good stuff by the people who wrote the book. I just wonder if it was too fast for the people who didn't know about it already, and too repeting for the others, but well, that's always the problem with these kind of things.

The hands-on session later was interesting: we had to understand several OWL ontologies and explain certain inferences, and Natasha Noy helped us with the new Protégé 3.1. It was harder than I thought quite some times. And finally Aldo Gangemi was giving us some exercises with knowledge representation design patterns, based on DOLCE. This was hard stuff...

Wow, this was a lot of namedropping. The social programme (we were hiking today) around the summer school, and the talks with the peers are sometimes even more interesting than the actual summer school programme itself, but this probably won't be too interesting for most of you, and it's getting late as well, so I just call it a day.

Summer School for the Semantic Web, Day 0

Arrived in Cercedilla today, at the Semantic Web Summer School. I really was looking forward to these days, and now, flipping through the detailed programme I am even more excited. This will be a very intense week, I guess, where we learn a lot and have loads of fun.

I was surprised by the sheer number of students being here: 56 or 57 students have come to the summer school, from all over the world - met someone from Australia, from Pittsburgh, and many Europeans. Happily, I also met quite a number of people I already knew, and thus I know it will be a pleasurable week. But let's just do the math for a second: we have more than 50 accepted students at this summer school. There are at least three other summer schools with related fields, like the one in Ljubljana the week before, there's one in Edinburgh, and the ESSLLI. So, that's about 200 students. Even if we claim that every single PhD student is going to a summer school - which I don't think - that would mean we get 200 theses every year! (Probably this number will be only reached in three years or so)

So, just looking at the sheer amount of people working on it - what's the expected impact?

Interesting times lie ahead.

Madrid Stadt

Mein letzter Blogeintrag aus Madrid war ja eher ein Schnellschuss aus dem Flughafen, diesmal habe ich ein wenig mehr Zeit. Das Hotel in dem ich abgestiegen bin, ansonsten brauchbar, wenn auch nichts besonderes - ich wuerde es nicht weiterempfehlen - hat laut Website Internetanschluss in allen Zimmern und WLAN. Was sie nicht haben, ist beides zusammen, WLAN auf dem Zimmern also, sondern man muss mit seinem Modemkabel in die Wand stoepseln. Und was sie auch auf der Website verschweigen ist der eher unhoefliche Preis von 9 Euro die Stunde...

Aber zurueck zu Madrid. Die Stadt selbst hat ein paar Autos zu viel, dafuer aber sprechen viel zu wenig Menschen Englisch. Na, was gehe ich auch ohne spanisch zu koennen nach Spanien koennte man einwerfen. Aber das Museum de Prada ist wirklich sehenswert: Velazquez Familia sieht so beeindrucken aus, wie ich sie mir vorgestellt habe, die Werke von Goya sind auf zwei Stockwerken ausgestellt: die lustigen, bunten ganz oben, die duesteren, wie der weit bekannte Saturn, darunter, in duesteren Raeumen. Sehr beeindruckend. Und die gewaltige Sammlung von Rubensbildern, allein die Menge an mythischen Figuren - wow. Da moechte man am liebsten nochmal ein Mythologielexikon rausgraben und sich darin eingraben.

Auch der Retito, der grosse Park in Madrid: sehr schoen, beeindruckend, gross. Nicht so gross wie der Stuttgarter Stadtpark, aber welche Stadt hat schon einen solch grossen Park? Die moderne Kathedrale der Stadt ist ebenfalls sehr auffaellig, einfach weil sie ganz anders ist als andere Kathedralen. Blau aufgemalte Himmelsflaechen? Sehr cool. Aber auch nur wegen der Einzigartigkeit, zugegeben.

Wenn man mich fragt, was ich mit Madrid verbinde, habe ich auch eine ganz deutliche Antwort.

Durst.

Joghurt und Coke

Was mir in Spanien sehr positiv auffiel: sie hatten viele Getränkeautomaten rumstehen. Nun, zugegeben, nicht überraschend. Durstig wie ich war suchte ich also gerade einen Getränkeautomaten, und als ich einen solchen erblickte, war ich erstaunt gleich daneben einen Joghurtautomaten zu finden. Was für eine coole Idee! Später fiel mir auf, dass das durchaus häufig der Fall war: überall verkaufte man Joghurt. Warum es das bei uns nicht gibt? Schönen, frischen kühlen Joghurt, überall, labend, lecker, ach, einfach herrlich, dachte ich, und kaufte eine Cola.

Klickfrei

Sehr coole Designidee: eine Webseite, die man vollständig navigieren kann, ohne zu klicken, dontclick.it. Sehr schnell, sehr flüssig und sehr hübsch. Ich stelle mir jetzt noch vor, dass wir keine Maus haben, sondern versuchen, mit unseren Augen den Cursor zu steuern - und schon haben wir ein extrem futuristisches User Interface...

Hilft auch bei RSI.

Wowarich?

Sehr nette idee, von Fred darauf gebracht:

Wo war ich schon überall auf der Welt, bzw. in Europa? (bei einer Weltkarte würde noch die USA dazukommen, der Rest wäre gähnendes Grau, darum habe ich lieber die Europakarte gewählt).

Hier fehlt noch ein Bild.

Könnt ihr auch ganz einfach für euch selber zusammenbasteln, auf World66.

Abraham Bernstein on users

"The regular user is not able to cope with strict inheritance."

Abraham Bernstein of the University of Zürich was today at the AIFB and gave a talk on SimPack - A Generic Java Library for Similarity Measures in Ontologies. Not being an expert in mapping, alignment and similarity I still saw some of the interesting ideas in it, and I liked the big number of different approaches towards measuring similiarity.

Which struck me much more was the above statement, which is based on his experience with, you know, normal users, who are "not brainwashed with object-oriented paradigms". Another example he gave was his 5 years old kid being perfectly able to cope with default reasoning - the "pinguins are birds, but pinguins can't fly"- thing, and thus do not follow strict inheritance.

This was quite enlightening, and leads to many questions: if the user can't even deal with subsumption, how do we expect him to be able to deal with disjunctions, complements or inverse functional properties?

Abraham's statement is based on experience with the Process Handbook, and not just drawn from thin air. There are a lot of use cases for the Semantic Web that do *not* require the participation of the normal end user, thus there still lie plenty of possibilities for great research. But I still believe that the normal end user has to unlock the Semantic Web in order to really make the whole idea lift off and fly. But in order to achieve that we need to tear down the wall that Abraham describes here.

Any ideas how to do this?

Garden State

Der Garden State ist New Jersey, wie Ralf mich freundlicherweise aufklärte. Und aus dem dem fernen, uns allen bekannten Los Angelese kommt der junge Held unserer Geschichte nach New Jersey, in seine Heimat zurück, und trifft auf manchen Geist seiner Vergangenheit, um erwachsen zu werden.

Schöner Film, spritzige Dialoge, skurrile Situationen, charmante Charaktere, treffend gezeichnet, und zudem glaubwürdig. Und dabei eher sparsam auf Sarkasmus und Ironie setzend, sondern vielmehr dieselbe abstrafen durch ehrliche Verrücktheit. Ich kann ihn nur empfehlen!

Eine deutlich längere und bessere Rezi von Garden State gibt es - wie üblich - bei Ralf.

Live from ICAIL

"Your work remindes me a lot of abduction, but I can't find you mention it in the paper..."

"Well, it's actually in the title."

Bologna la dotta

Bologna ist großartig! Das erste Gebäude. das ich hier kennenlernte, war die Sala Borsa. Angekommen, im Hotel eingecheckt, spazieren, und sofort reinmarschiert. Man könnte es einen Mall nennen, aber mit einem sehr ausgewählten Angebot: zwei, drei Bibliotheken, Mediothek, Buchhandlungen, Studentenbedarf (Taschen, Blöcke), Internetcafé, WLAN-Access, Restaurants, unglaublich! Das ganze in einem wunderschänen, dezent renovierten alten Gebäude, das auf einer Ruine gebaut ist, wahrscheinlich aus römischer Zeit. Die Ruine kann man sehen, weil der Boden des Erdgeschosses aus Glas besteht, das ganze Gebäude ist eine große Halle, mehr oder weniger, mit mehreren Galerien, in der die ganzen tollen Geschäfte untergebracht sind.

Phantastischer Ort. Allein deshalb ist Bologna eine Reise wert. Ja, die Universität (gegründet 1088, damit die älteste Uni der Welt) ist auch ganz ansehnlich. Vorlesungen in diesen Hallen zu hören oder Prüfungen abzulegen in Renessaincegeschmückten Räumen wird schon irgendwie was besonderes sein. Daher hat Bologna auch einen seiner Beinamen, Bologna la dotta, Bologna, die Gelehrte.

Auch die Konferenz ist überraschend spannend, aber dazu bald mehr auf Semantic Nodix.

Angelina Jolie wird 30

Bei dieser Gelegenheit erfuhr ich im Radio, dass die Dame auch bei Meat Loaf in einem Video auftrat. Ich versuchte mich krampfhaft durch die Meat Loaf Videos zu erinnern, und von der Zeit her wäre das einzig passende I'd do anything for love (but I won't do that) dachte ich. Und während ich mich so erinnerte, vermeinte ich das Bild der Hauptdarstellerin aus dem Video herauszubeschwören, und war mir in der Erinnerung schon ganz und gar sicher, ja, das war Angelina Jolie!

Heute abend recherchierte ich dann doch ein wenig. Laut imdb spielte Angelina Jolie in Bat out of Hell II: The Picture Show mit. Dieses wiederum ist laut Rotten Tomatoes eine Sammlung von Videos, darunter eben auch besagter Song! Doch Angelina soll einen Runaway gespielt haben, was nicht passt - in dem Video kam kein Runarway vor. Viel mehr wurde die Rolle von Mrs Loud gespielt, die Laut Wikipedia in Wirklichkeit Lorraine Crosby heißt. War es dann Rock'n'Roll dreams come true? Da kam ein Runaway vor.

Ergebnis: Lorraine Crosby sieht so aus. Angelina Jolie so. In meiner Erinnerung sehe ich aber, wenn ich an das Video zu I'd do anything etc. denke nur mehr nur noch Angelina, und nicht Lorraine. Diese verdammte Erinnerung ist doch ein zu wackeliges Ding, ich sollte mich gar nicht mehr darauf verlassen...

Was ich aber nicht herausgefunden habe: in welchem Meat Loaf Video spielte die Jolie denn jetzt mit? Weiß das jemand?

Touristenfalle

Diese Woche auf Kreta, in einem gewaltigen Touristenkomplex. Alles ist strahlend weiß oder himmelblau, das Wetter ist herrlich, der Strand gleich um die Ecke, überall gibt es Möglichkeiten zu Essen, Trinken, Einkaufen, das ganze Krams, man muss den Komplex gar nicht verlassen, ja selbst die Konferenzräume der ESWC2005, die mich nach Kreta führt, finden sich innerhalb des Hotels, und auch das Conference Dinner fand hier statt.

Letzte Woche, Granada, die World Conference on Philosophy of Law and Social Philosophy. Die Konferenzräume waren deutlich beeindruckender, das Essen aber auch schlechter. Die Unterkunft? Mit Kollegen zusammen quartierten wir uns in den umliegenden Bergen in einem Haus ein. Die Räume der Konferenz waren direkt in der Stadt. Social Event - Dinner? Nein, ein ein Besuch der Alhambra. In Kreta gab es kein kulturelles Programm - leider.

Und die Moral von der Geschichte? Noch gar keine, weil das wichtigste nach wie vor die Präsentationen, die Leute und die Inhalte. Und hier wie da waren ausgesprochen schlaue Leute - aber natürlich lag die ESWC mir mehr (auch wenn ich auch auf der World Conference manch Neues lernte). Aber Habermas zu hören war dennoch ein Erlebnis!

ESWC2005 is over

The ESWC2005 is over and there have been a lot of interesting stuff. Check the proceedings! There were some really nice idea, like RDFSculpt, good work like temporal RDF (Best Paper Award), the OWL-Eu extensions, naturally the Karlsruhe stuff like ontology evolution, many many persons to meet, get to know, many chats, and quite some ideas. Blogging from here is quite a mess, the uplouad rate is catastrophal, so I will keep this short, but I certainly hope to pick up on some of the talks and highlight the more interesting ideas (well, interesting to me, at least). Stay tuned! ;)

OWL 2.0

I posted this to the public OWL dev mailing list as a response to a question posed by Jim Hendler quite some while ago. I publish it here for easier reference.

Quite some while ago the question of OWL 2.0 was rised here, and I wrote already two long replies with a wishlist - but both were never sent and got lost in digital nirvana, one due to a hardware, the second due to a software failure. Well, let's hope this one passes finally through. That's why this answer is so late.

Sorry for the lengthy post. But I tried to structure it a bit and make it readable, so I hope you find some interesting stuff here. So, here is my wishlist.

1. I would like yet another OWL language, call it OWL RDF or OWL Superlite, or whatever. This is like the subset of OWL Lite and RDFS. For this the difference between of owl:Class and rdf:Class needs to be somehow standardly solved. Why is this good? It makes moving from RDF to OWL easier, as it forces you to keep Individuals, Classes and Relations in different worlds, and forgets about some of the more sophisticated constructs of RDF(S) like lists, bags and such. This is a real beginners language, really easy to learn and implement.
2. Defined Semantics for OWL FUll. It is unclear -- at least to me -- what some combinations of RDF(S)-Constructs and OWL DL-constructs are meant to mean.
3. Add easy reification to OWL. I know, I know, making statements about statements is meant to be the root of all evil, but I find it pretty useful. If you like, just add another group of elements to OWL, statements, that are mutually disjoint from classes, instances and relations in OWL DL, but there's a sublanguage that enables us to speak about statements. Or else OWL will suck a lot in comparison to RDF(S) and RDF(S) + Rules will win, because you can't do a lot of the stuff you need to do, like saying what the source of a certain statement is, how reliable this source is, etc. Trust anyone? This is also needed to extend ontologies toward probabilistic, fuzzy or confidence-carrying models.
4. I would love to be able to define syntactic sugar, like partitionOf (I think, this is from Asun's Book on Ontology Engineering). ((A, B, C) partitionOf D) means that every D is either an A or a B or a C, that every A, B or C is a D, and that A, B and C are mutually disjunct. So you can say this already, but it needs a lot of footwork. It would be nice to be able to define such shotcuts that lever upon the semantics of existing constructors.
5. That said, another form of syntactic sugar - because again you can use existing OWL constructs to reach the same goal, but it is very strenuous to do so - would be to define UNA locally. Like either to say "all individuals in this ontology are mutually different" or "all individuals with this namespace are mutually different". I think, due to XML constraints the first one would be the weapon of choice.
6. I would like to be able to have more ontologies in the same file. So you can use ontologies to group a number of axioms, and you also could use the name of this group to refer to it. Oh well, using the name of an ontology as an individual, what does this mean? Does it imply any further semantics? I would like to see this clarified. Is this like named graphs?
7. The DOM has quite nicely partitioned itself in levels and modules. Why not OWL itself? So you could have like a level 2 ontology of mereological questions, and such stuff, all with well defined semantics, for the generic questions. I am not sure there are too many generic questions, but taxonomy is (already covered), mereology would be, and spatiotemporal and dynamic issues would be as well. Mind you, not everyone must use them, but many will need them. It would be fine to find stan dard answers to such generic questions.
8. Procedural attachments would be a nice thing. Like have a a standardized possibilities to add pieces of code and have them executed by an appropriate execution environment on certain events or requests by the reasoner. Yes, I am totally aware of the implications on reasoning and decidability, but hey, you asked what people need, and did not ask for theoretical issues. Those you understand better.
9. There are some ideas of others (which doesn't mean that the rest is necessarily original mine) I would like to see integrated, like a well-defined epistemic operator or streamlining the concrete domains to be more consistent with abstract domains, or to define domain and range _constraints_ on relations, and much more. Much of this stuff could be added optional in the sense of point 7.
10. And not to forget that we have to integrate with rules later, and to finally have an OWL DL query language. One goal is to make it clear what OWL offers over simply adding rules atop of RDF and ignoring the ontology layer completely.

So, you see, this is quite a list, and it sure is not complete. Even if only two or three points were finally picked up I would be very happy :)

D'Artagnans Tochter

Am Samstag war ich - zum ersten mal überhaupt - in einer Theaterpremiere: D'Artagnans Tochter, im Alten Schauspielhaus in Stuttgart, geschrieben von Tom Finn und Volker Ullmann.

Kurz gesagt: hat sehr viel Spaß gemacht! Es war sehr flott, Mantel und Degen auf der Bühne, ein netter Plot, lustig, und vor allem das erste: Flott. In den Szenenwechselns fliegen die Schauspieler über die Bühne, kein Moment Langeweile, kaum scheint man in ruhigen Gewässern angekommen zu sein, stürmen die Schergen des Kardinals heran.

Fiese Bösewichte, die Musketiere sind so dargestellt, wie wir sie kennen, der König wird wunderbar gespielt - viel Spaß, viel Spannung - anschauen! Geh mal wieder ins Theater.

Semantic Scripting

Oh my, I really need to designate some time to this blog. But let's not ranting about time - no one of us has time - let's directly dive into my paper for the Workshop on Scripting for the Semantic Web on the 2nd ESWC in Heraklion next week. Here is the abstract.

Python reached out to a wide and diverse audience in the last few years. During its evolution it combined a number of different paradigms under its hood: imperative, object-oriented, functional, listoriented, even aspect-oriented programming paradigms are allowed, but still remain true to the Python way of programming, thus retaining simplicity, readability and fun. OWL is a knowledge representation language for the definition of ontologies, standardised by the W3C. It reaps upon the power of Description Logics and allows both the definition of concepts and their interrelations as well as the description of instances. Being created as part of the notoriously known Semantic Web language stack, its dynamics and openness lends naturally to the ever evolving Python language. We will sketch the idea of an integration of OWL and Python, but not by simply suggesting an OWL library, but rather by introducing and motivating the benefits a really deep integration offers, how it can change programming, and make it even more fun.

You can read the full paper on Deep Integration of Scripting Languages and Semantic Web Technologies. Have fun! If you can manage it, pass by the workshop and give me your comments, rants, and fresh ideas - as well as the spontaneous promise to help me design and implement this idea! I am very excited about the workshop and looking forward to it. See you there!

Granada ist phantastisch

Hier in Granada, auf dem XXII. Weltkongress der Philosophie des Rechts, ist es wahnsinn. Phantastisches Wetter, bekannte Sprecher, viele, viele Leute - über 900 Teilnehmer! - ein Wahnsinns Konferenzgebäude, und bei unserem Workshop kamen einige spannende Fragen und Diskussionen auf. Der Vortrag sei sehr gut gelaufen (ic bin mir nur selber nie dessen sicher). Die Abende sind lang und anregend, die morgen dafür schwer zum Aufstehen. Schade, dass ich nicht bis zum Schluss bleiben kann, aber morgen ist die Theaterpremiere von D'Artagnans Tochter, aus der Feder von Tom Finn, zu der ich eingeladen bin, und dazu muss ich halt wieder in Stuttgart sein. Und am Sonntag geht es auf die ESWC...

Das Leben ist schön.

Flughafenblogging

Richtig fies: morgens um 3:30 aus dem Bett zu gehen, um dann in Madrid zwei Stunden lang am Flughafen warten zu muessen.

Gruß aus Madrid!

Standpunkt (nicht meiner!)

"We could really speed up the whole process of drug improvement if we did not have all the rules on human experimentation. If companies were allowed to use clinical trials in Third World countries, paying a lot of poor people to take risks that you wouldn't take in a developed country, we could speed up technology quickly. But because of the Holocaust --"

Dark Side of Popularity

"I actually worry a lot that as I get "popular" I'll be able to get away with saying stupider stuff than I would have dared say before. This sort of thing happens to a lot of people, and I would *really* like to avoid it."

Wenn Nerds protestieren

Wer versteht schon so ein Schild?

Wann gibt es das bei den Studentenstreiks hierzulande? (Und überhaupt, was bedeutet es, wenn Studenten streiken? Dass sie die Arbeit niederlegen?)

Pflichtlektüre

Der Aufstieg Chinas zur politischen und wirtschaftlichen Weltmacht

Teure Taxis

Mein erster Blogeintrag aus Sofia!

Eigentlich ist hier das Taxi spottbillig - also im Verleich zu westlichen Ländern. Drei bis vier Leva für zehn bis fünfzehn Kilometer. Aber manchmal erwischt man ein Taxi, dass nicht OK ist (im wahrsten Sinne des Wortes: die zu empfehlende Taxifirma hier ist OK Taxi) - und dann kostet es leicht das Sechsfache.

Das seltsame ist, dass es immer noch günstiger ist als bei uns, und so richtig zu beschweren möchte man dann auch nicht. Zumal wenn man die Sprache nicht beherrscht.

Mit dem eigenen Auto herzukommen ist zudem noch eine besonders dumme Idee, weil es hier eine besonders interessante Regelung gibt: wenn man sein Auto einführt, und es dann gestohlen wird, und man es entsprechend nicht mehr ausführen kann - muss man an der Grenze zudem noch Strafzoll nachzahlen...

Internet jetzt auch Offline

Ihr braucht das Internet bloß hier online runterzuladen, und schon könnt ihr darin ganz ohne Netzverbindung surfen. Cool, ne?

Eine Stimme im Himmel

"Wolfgang, bist Du Dir wirklich sicher?"

Man sitzt ganz gemütlich im Flugzeug. Am Anfang erfährt man noch, dass nicht der Kapitän, sondern der erste Offizier fliegt. Dann, plötzlich, über die Lautsprecher kam der oben stehende Satz. Und man denkt sich: oh, der Anfänger scheint Schwierigkeiten zu haben und fragt den Chef. Zumal es ein wirklich turbulenter Flug ist (im wörtlichen Sinne).

"Wolfgang, hier spricht Dein Gewissen - bist Du Dir wirklich sicher?"

Was bedeutet das? Hat der Offizier, oder gar der Kapitän zufällig den falschen Schalter umgelegt? Doch die Auflösung folgt stante pede, nach dem Wetterbericht:

"Allen Fluggästen einen schönen Tag und wir hoffen, dass Wolfgang seine Entscheidung, das Junggesellendasein zu beenden nicht bereuen wird."

Puh...

Bosc de les Fades

Das - für mich - beeindruckendste Restaurant / Café / Bar -Dings in Barcelona war ganz eindeutig das Bosc de les Fades (Feenwald) welches irgendwie zum Wachsmuseum gehört (von der Wachsmuseumswebsite kommt ihr auf die offizielle Webseite des Bosc de les Fades, ist leider nicht direkt verlinkbar).

Das Ding ist eine Bar, jedoch derart gestaltet, dass sie jedes Rollenspielers Herz (und überhaupt von jedem, der auf Fantasy und Märchen steht) höher schlagen lässt. Ein Feenwald, ein verwunschenes Zimmer, Burgkämmerlein, und manches mehr bilden die Elemente dieser Bar. Die Bilder auf den verlinkten Seiten geben nur ein sehr ungenügendes Bild ab. Sollte es euch nach Barcelona verschlagen, auf keinen Fall verpassen! Einfach zum Wachsmuseum am südlichen Ende der Rambla, und vor dem Eingang einfach rechts.

Und nächstes mal muss ich auch das Wachsmuseum selber besuchen. Ich dachte, nach dem Madame Tussauds und dem Dungeon in London würde das Barceloner Museum nichts spannendes enthalten können - doch ein Museum dass mit Statuen von Superman und C3PO am Eintritt wirbt könnte interessanter sein als gedacht.

Danke an Núria für den Tipp!

Unique Name Assumption - another example

Ian Davis has a very nice example illustrating the Unique Name Assumption: "Two sons and two fathers went to a pizza restaurant. They ordered three pizzas. When they came, everyone had a whole pizza. How can that be?"'

Better than my examples. And much shorter!

Sagrada Familia

Ich bin zwar schon zurück aus Barcelona, aber so zwei, drei Nachwehen werde ich dazu noch bloggen. Heute: die Sagrada Familia, die Kathedrale der Heiligen Familie zu Barcelona (noch im Bau). Man kommt hin, und muss schlappe 8 Euro hinblättern für den Eintritt. Erscheint viel, ist es auch.

Aber wie berechnet man den Eintritt für etwas, das wirklich einzigartig ist? Man sieht vor allem eine Baustelle, umgeben von den gewaltigen bestehenden Türmen. Der Aufzug nach oben kostet nochmal 2 Euro, und der Treppenaufgang ist versteckt und finster und dunkel - und sehr lohnenswert. Der Blick über Barcelona, den man von da oben genißen kann, ist nur das Sahnestück, das eigentlich unglaubliche ist die Kathedrale selbst. Höher und höher, Scharten, Fenster, Durchblicke überall, immer wieder fällt der Blick durch ein Fenster, genau auf ein golden Geschriebens Wort, auf eine Engelsfigur, auf eines der unzähligen Elemente der Kathedrale.

Wie gewaltige Mammutbäume schmiegen sich die Säulen an eines der vier Portale, alles scheint gen Himmel zu fließen, überall Zitate aus Natur und Geschichte. Das Museum öffnet einem die Augen für zahlreiche Details, zeigt die Tricks für die fließende Wirkung, entschlüsselt manches Detail aus der Natur, und ich blieb staunend zurück mit der Frage, was Gaudi heute mit einem CAD-Programm anstellen würde, ob er genialer, ob er konservativer wäre...

Teuer, aber sehenswert. Und zudem ein schönes Glockenspiel. Und sehr, sehr hoch...

Barcelona II

Wieder in Barcelona. Nachdem letztes Mal im November so ein Traumwetter war, war ich diesmal leicht gekleidet losgeflogen - und prompt ist es kälter als im Ländle. Würde mich nicht überraschen, wenn ich eine Erkältung mitschleppe...

Aber dafür habe ich diesmal sogar etwas Zeit, mir die Stadt anschauen. Wahnsinnggemütliche kleine Bars wie die Eclectica, supertolle Restaurants wie die Muscleria, etc. Die letzten zwei Tage war ich mit Barcelonesen unterwegs, heute mit Kai, einem Erasmusstudenten, und seiner Schwester Rosa. Spannend, wie die unterschiedlichen Einstellungen zu den Sehenswürdigkeiten der Stadt sind, was sie empfehlen, wo sie hingehen.

Die Stadt ist toll! Heute schaue ich noch die Sagrada Familia an, das freue ich mich besonders darauf. Und dann brauche ich ganz dringend Schlaf...

New OWL tools

The KAON2 OWL Tools get more diverse and interesting. Besides the simple axiom and entity counter and dumper, the not so simple dlpconverter, and the syntactic transformer from XML/RDF to OWL/XML and back, you now also have a filter (want to extract only the subClassOf-Relations out of your ontology? Take filter), diff and merge (for some basic syntactic work with ontologies), satisfiable (which checks if the ontology can have a satisfying model), deo (turning SHOIN-ontologies in SHIN-ontologies by weakening, should be sound, but naturally not complete) and ded (removes some domain-related axioms, but it seems this one is still buggy).

I certainly hope this toolbox will still grow a bit. If you have any suggestions or ideas, feel free to mail me or comment here.

Kebab Connection

aus der Reihe Filme in 50 Worten

Montag, Sneak im Metropol. Eine der Regeln der Sneak: ein Film, der eine Preview bekommt, kommt nicht in der Sneak. Wurde Montags gebrochen.

Zum Glück. Weil den Film hätte ich sonst nicht gesehen. Dem Titel nach erwartete ich eine platte Komödie über Türken der zweiten Generation, die voll auf cooler Lan, blöde Sprüche, und zwischen den Knöcheln hängende Hosen stehen. Stattdessen: ein witziger Film, mit einer glaubhaften Geschichte, der Klischees nicht nur bedient, sondern sie an den richtigen Stellen auch ernst nimmt und konsequent weitertreibt. Wenn der Vater den Sohn als Sohn eines Esels beschimpft, weil er weiß, dass er im Unrecht ist, oder er verzweifelt versucht, seine Fehler wegzuerklären, weil er zu stolz ist, sie als solche zuzugeben, dann sehen wir überzeugend dargestellte Szenen. Kurz: ein wirklich guter Film, der leider wegen des Marketings und des Titels den größten Teil der potenziellen Zuschauer verfehlen könnte.

One Day in Europe

Aus der Reihe Filme in 50 Worten

Letzten Freitag war im Delphi eine kleine Premiere dieses Streifens, mitsamt Hauptdarstellern, Regisseur und so ein Krams. Das drumherum ist zwar nett, aber hier gehts trotzdem nur um den Film, und der war - trommelwirbel! - lustig, schnell, bildreich, musikalisch prima unterlegt, überzeugend gespielt, interessante Charaktere, und allerlei sonst.

Vier Episoden in Moskau, Istanbul, Santiago de Compostela und Berlin erzählen von kleinen Ereignissen, die in Europa geschehen. Weil es eben nicht um dramatische, existenzielle Dinge geht, hat der Zuschauer die Muse und der Film die Zeit die ganzen vielen Details aufzuzeigen.

Auch sehr nett: auf die Frage, was der Regisseur denn von Europa halte, antwortete er: "Ich maße mich nicht an, über das Vereinigte Europa zu orakeln. Ich weiß nicht, ob es in 20 oder 40 oder 60 Jahren da ist..." Aber dass es da sein wird, schien er nicht einen Moment zu bezweifeln. So ähnlich auch der Film: die verbindenden Elemente Europas sind Sprachenwirrwar und Fußball (und Diebstahl und Versicherungsbetrug, na gut).

Kurz: wer die Gelegenheit bekommt, anschauen! Der Film lohnt sich.

MinCardinality

More on the Unique Name Assumption (UNA), because Andrew answered on it, with further arguments. He quotes Paul: " The initial problem was cardinality and OWL Flight attempts to solve the problem with cardinality. Paul put it succinctly: "So what is the point of statements with the owl:minCardinality predicate? They can't ever be false, so they don't tell you anything! It's kind of like a belt and braces when your belt is unbreakable." "

Again I disagree, this time to Paul: the minimal cardinality axiom does make sense. For what, they ask - well, for saying that there is a minimal cardinality on this relation. Yeah, you are right: this is an axiom which hardly can lead to an inconsisten ontology. But so what? You nevertheless can cut down the number of possible models with it and get more information out of the ontology.

"I would agree - this was my main problem - how do you explain to Joe (and Andrew) that all his CDs are the same rather than different."

That's turning around the argument. If the reasoner would claim that all of Joes CDs are the same, he would be doing a grave mistake. But so would he if he would claim that all are different: the point is, he just doesn't know. Without having someone to state sameness or difference explicitly, well, you can't know.

"I did comment that the resolution, local unique names using AllDifferent, didn't actually seem to solve the problem well enough (without consideration for scalability for example)."

I am not sure why that should be. It seems that Andrew would be happy if there was a file-wide switch claiming "If I use different URIs here I mean different objects. This file makes the UNA." These files would easily be translated to standard OWL files, but there would be less clutter inside (actually, everything that would need to be done is adding an axiom of allDifferent with all the names of the file).

"I have a feeling that context is a better solution to this problem (that might just be my golden hammer though)."

I don't understand this one, maybe Andrew will elaborate a bit on this.

If you imagine an environment with axioms floating around, from repository to repository, being crawled, collected, filtered, mapped and combined, you must not make the Unique Name Assumption. If you remain in your own personal knowledge base, you can embrace UNA. And everything you need between is one more axiom.

Is it that bad?

Hannover spielt

Die diesjährige Hannover spielt 2005 war... langweilig.

Die letzte Hannover spielt die ich besuchte war Mitte der 90er. Es waren damals um die 2000 Besucher da, zahlreiche Workshops liefen ständig und parallel, unzählige Ehrengäste gaben sich die Klinke in die Hand. War's R. A. Salvatore, den ich damals sah? Viele Leute lernte ich damals kennen, die ich heute noch gerne und viel zu selten sehe. Es war toll.

Über Jahre hinweg verplante ich es stets, nach Hannover zu fahren. Dieses Jahr ergab sich die plötzliche Situation, dass der Samstag frei wurde, weil ich eine Abgabe überraschenderweise vor der Zeit schaffte (Osterwochenende sei dank, mein Text für Rückkehr des Kaisers ist draußen). Also in den Zug gesetzt und ab nach Hannover (etwas mehr als 3 1/2 Stunden - super!).

Wenn das ein Spielecon vor der Haustür gewesen wäre, in Tübingen, in Villingen-Schwenningen, gar hier in Stuttgart, das wäre OK. Aber früher hatte sich eben auch eine viel längere Strecke gelohnt! Und das ist es, was ich vermisse. Kaum Programm, kaum bekannte Gesichter, vielleicht 200 Besucher, die Überreichung des Goldenen Bechers war, nun, auch weniger spektakulär als früher, ah ja. Ich glaube, das war meine letzte Hannover spielt.

Allerdings, ich tue dem Con unrecht. Ich hörte, die Veranstalter hätten sich mit Absicht für ein Downsizing entschieden, um das ganze besser zu verwalten und weniger stressfrei zu machen. Ein nachvollziehbarer und mutiger Entschluss. Und ich bin kaum Con-Spieler: mich interessieren die Workshops und die Gelegenheit, Leute zu treffen und zu planen. Insofern ist die Aussage einfach: ich war nicht Zielruppe, und, wie gesagt, tue damit der Hannover Spielt deutlich unrecht. Ich bin mir sicher, es wird wieder Conberichte geben, die mit Spielerlebnissen und viel Spaß aufwarten werden - jeder soll sich also selber die Nachlese aussuchen, die ihm am besten liegt.

Die gute Nachricht: ein paar liebe Menschen gabelten mich auf und brachten mich dann zur Ostermühle, wo ich dann einen Abend und einen Morgen viel mehr nach meinem Geschmack verbrachte. Danke für diese Gelegenheit!

Pforzheim

Soeben, beim ein paar Links zu Blogs verfolgen...

Ich: "Schon wieder Pforzheim! Ich glaube, Pforzheim hat die größte Blogdichte der Welt..."
WG-Mitbewohnerin: "Vielleicht haben die dort sonst nichts zu tun?"

Ich bin mir auch ganz sicher, Pforzheimer haben alle ganz, ganz viel Humor... ;)

Unique Name Assumption

I just read Andrew Newman's entry on the Unique Name Assumption (UNA). He thinks that not having an UNA is "weird, completely backwards and very non-intuitive". Furher he continues, that "It does seem perverse that the basis for this, the URI, is unique." He cites an OWL Flight paper that caused me quite some headache a few weeks ago (cause there was so little in it that I found to like).

Andrew, whose blog I really like to read, makes one very valid point: "It doesn't really say, though, why you need non-unique names."

There was an OWL requirement that gives a short rationale for the UNA, but it seems it is not yet stated obvious enough.
Let's make a short jump to the close future: the Semantic Web is thriving, private homepages offer rich information sources about anything, and even the companies see the value of offering machine-processable information, thus, ontologies and knowledge bases everywhere!

People want to say how they liked the movie they just saw. They enrich their movie review with an RDF-statement that says

http://semantic.nodix.net/movie#Ring_2 http://semantic.nodix.net/rating#rated http://semantic.nodix.net/rating#4_of_5.

Or rather, their editor creates this statement automatically and publishes it along the review.

I'd be highly surprised if imdb would use the same URI for denoting the movie. They would probably use an imdb-URI. And so could I, using the imdb-specified URI for the movie. But I didn't, and I don't have to. If I want to state that this is the same movie, I can assert that explicitly. If I had UNA, I couldn't do that. The two knowledge bases could not work together.

With UNA, many knowledge bases relying on inverse functional properties would break as well. FOAF, for examples, uses this, identifiying persons with an IFP of their eMail-Hash. With UNA, this wouldn't work anymore.

Let's take another example. On my mothers webpage there could be a statement saying she has three kids, Jurica, Rozana and Zdenko. I would state on my page that I am my moms kid. My sister, being the social kind, tells the world about her mom and her two brothers, Jurica and Denny.
Now, if we have UNA, a reasoner would infer that one of us is lying. But all of us are very honest, trustworthy people. The problem here is, that my name is Zdenko, but most people refer to me as Denny. UNA says that Denny and Zdenko are the same person. If we have no UNA, we wouldn't believe that. But still we can state it explicitly: my mom could have said that she has three kids, Jurica, Rozana and Zdenko, and those are mutually distinct. Problem solved.

You could say, wait, if we had UNA we still could just claim that Zdenko owl:sameAs Denny, and the problem wouldn't arise. That is true. But then I would have to consider my moms statements. That maybe OK on a scale like this, but imagine this in the wilds of the web - you would have to consider every statement made about something, before you may state something as well. Impossible! And you would introduce non-monotonic inferences, and you probably wouldn't really want that.

What does this mean? Let's take the following row of statements, and consider the answer to the question "Is Kain on of Adams two sons?". So we know that Adam has two sons, and that there is an entity named Kain.

Adam fatherOf Abel.

UNA and non-UNA both answer: don't know.

Adam fatherOf Cain.

UNA says "No, Kain is no son of Adam". non-UNA says: "Sorry, I still don't know".

Cain sameAs Kain.

UNA says "Yes, Kain is a son of Adam (hope you didn't notice my little lie seconds before)". non-UNA says: "Yes, Kain is a son of Adam".

Assuming that, instead of the last statement, we claimed that

Adam fatherOf Kain.

UNA would say: "I'm messed up, I don't know anything, my database is inconsistent, sorry." , whereas non-UNA would answer: "Yes, Kain is a son of Adam (and by the way, maybe Kain and Abel are the same, or Kain and Cain, or Abel and Cain)."

The problem is, that in the setting of the Semantic Web you have a World Wide Web with thousands of facts, always changing, and you must assume that you didn't fetch all the information about a subject. You really can't know if you know everything there is about Adam. But you still want to be able to ask questions. And you want to get answers, and these answers to be monotonic. You don't want the Semantic Web to answer one day "No", the other "Yes" and sometimes "I don't know", but you could be fine with having it either provide the correct answer or non at all.

OWL-Flight and proponents of UNA actually forgot that it's a Semantic Web, not just a Semantic Knowledge Base. If you want UNA, take your Prolog-engine. The Semantic Web is more. And therefore it has to meet some requirements, and UNA is an astonishingly basic requirement of the Semantic Web. Don't forget, you can create local unique names if needed. But the other way would be much harder.

Still, Andrews arguments lead to a very important question: taking for granted that Andrew is an intelligent guy with quite some experience with this kind of stuff, how probable is it, that Joe Random User will have really big problems with grasping such concepts as non-UNA? How should the primers be written? How should the tools work in order to help users deal with this stuff - without requiring the user to study these ideas in advance?

Still a long way to go.

Ring 2

Filme in 50 Worten

Angst. Anspannung. Ring 2 ist die würdige Fortsetzung von Ring. Wie soll ich sagen? Kinder sind der größte Horror.
Wir tauchen tiefer in die Geschichte von Samara ein, und wieder sehen wir, wie Rachel um ihren Sohn kämpft. Der Mut, den sie dabei aufbringt, grenzt ans unglaubwürdige - bis man sich vor Augen hält, dass sie um das blanke Leben ihres Kindes kämpft.

Ring ist bislang der einzige Horror-Film, der mir überhaupt gefiel - und ich habe so manchen gesehen. Es ist insbesondere, der einzige, der Horror herberief. Nun gesellt sich Ring 2 dazu.

So spannend, dass ich ganz verspannt im Kino saß, und danach echt verspannt war...

Auch das Internet hat ein Ende

Und zwar hier.

Und wieder zu den Google-Suchen

Bei den drei Google-Anfragen von letzter Woche ist zwar etwas Ruhe eingekehrt, aber ein weiterer Effekt ist zu beobachten: bei allen drei Anfragen (geruch der luft nach regen, gefühl von schnee auf der haut, eigene wahrnehmung von dem gefühl von schnee auf der haut) ist genau dieser Blog der Nummer 1-Hit geworden.

Die armen Leute, die auf der Suche nach dem Geruch der Luft nach Regen sind, und das einzige, was sie bekommen, ein Blogeintrag ist, der sich genau darüber lustig macht...

Unter Brüdern

Aus der hochbeliebten, aber nur unregelmäßig fortgeführten Reihe 'Filme in 50 Worten'

Hiermit möchte ich meine Rolle als Multiplikator wahrnehmen, und darauf hinweisen, dass ich über Buddy, und der über den KulturSpiegel, gestern für umme in die Preview des dänischen Films Brothers reingehen konnte. Der hatte mich im Vorfeld nicht wirklich interessiert, aber was man tut man nicht für kein Geld...

Nun ja, der Film überraschte mich. Glaubwürdige Geschichte, überzeugende Darsteller. Drama. Aber so richtig, mit Tränen und verzwickten Situationen, mit Sturköpfen und Helden. Der Krieg in Afghanistan, Angst vor dem eigenen Vater, der Tod eines geliebten Menschen, Besaufen in der Kneipe, Väter, die unverzeihliches sagen - all das wird dargestellt, nicht gewertet, was ich geradezu bewundernswert finde.

Schade, dass manche Szenen übergangen wurden. Hätte ich gerne gesehen, wie der Bruder erfährt, dass sein Bruder gar nicht tot ist. Da wurde geschnitten. Auch das Ende ist dann etwas mittendring statt schon vorbei. Andere Handlungen sind für mich kaum nachvollziehbar. Aber so sind Menschen halt. Auch schade ist: dadurch, dass die Erzählweise nicht wertet, nehmen wir auch nicht so viel mit. Als ob man hier wirklich nur eine Geschichte erzählen wollte, ohne Nachricht. Niemand will mir etwas sagen in dem Film. Es passiert einfach. So wie das Leben. Ob man das von einem Film will mag man selber entscheiden.

Wer Dramen mag, wer gut erzählten, echt wirkenden Geschichten gerne folgt - der sollte sich diesen Film anschauen. Niemand wird aber wegen einer Kulturlücke ausgelacht werden, wenn er den Film doch verpasst.

So, Multiplikatordienst erfüllt. Wann kriege ich die nächste Freikarte?

AIFB OWL tools

Working with ontologies isn't yet as easy as it could be - especially because the number of little helpers is still far too small. After having written dlpconvert and owlrdf2owlxml (the tool with the maybe most clumsy name in the history of the Semantic Web) I noticed how easy it would be to write some more tools based on Boris' KAON2 OWL ontology infrastructure.

And so I went ahead. First I integrated dlpconvert and owlrdf2owlxml (or short, r2x) in it, then I added a simple ontology dumper and axiom and entity counter. Want to know how many individuals are in your ontology? Simply type owl count myontology.owl -individual, and there you go. Want a list of all Classes? Try owl print myontology.owl -owlclass. It's as easy as that.

I'm totally aware that this functionality maybe isn't worth the effort of building a tool for. But this is just a beginning: I want to add more functionality to filter, merge, compare and much more to it. The point is, at the end having a handy little set of OWL tools you can work with. I miss that really with OWL, and now here it is. At least, a beginning.

Grab your copy now of the AIFB OWL Tools.

Philosophische Grundlagen

I had a talk on Philosophical Foundations of Ontologies last week at the AIFB. I prepared it in German (and thus, all the slides were in German) and just before I started I got asked if I may give the talk in English.

Having never heard a single lesson in philosophy in English and having read English philosophy only on Wikipedia before, I said yes. Nevertheless, the talk was very well perceived, and so I decided to upload it. It's pure evil PowerPoint, no semantic slides format, and I didn't yet manage to translate it to English. If anyone can offer me some help with that - I simply don't know many of the technical terms, and I don't have ready access to the sources - I would be very happy! Just drop me a note, please.

Philosophische Grundlagen der Ontologie (PowerPoint, ca. 4,5 MB)

Broken link

Boogey-Man

Ich habe hier schon länger keine Filmrezensionen mehr geschrieben, leider. Und ich will für diesen Film auch nicht damit anfangen, weil es sich dafür nicht lohnt, und zudem Schwesterchen wie auch Buddy schon ihren Senf dazugegeben haben.

Warum ich trotzdem dazu schreibe? Weil Telepolis eine lobende Rezi zu diesem Film gemacht hat. Wer dies liest, muss sich fragen, ob sie vielleicht ernsthaft einen anderen Film gesehen habe. Beim Hamburger Abendblatt konnte ich mich irgendwie deutlich eher wiederfinden...

Lange Nacht der Museen

Ist es eigentlich Etikettenschwindel bei der langen Nacht der Museen von einer lange Nacht zu sprechen? Die hört ja schon um 2 auf!

Gestern war in Stuttgart wieder die Lange Nacht der Museen. Diesmal leider ohne mich, da ich in Karlsruhe noch auf der DenkWerkzeug 2005 war (die wiederum einige Aha-Erlebnisse und interessante Einsichten erbrachte), und ich erst nach Mitternacht in Stuttgart aufschlug (weil ich nicht bedachte, dass Samstags die Züge anders fahren).

Hätte sie wirklich lange gedauert, wäre ich noch hingegangen. Für anderthalb Stunden aber 12 Euro auszugeben, nun ja, ich weiß nicht. Ironisch: die Rückfahrt dauerte dann fast so lange, wie die Museumsnacht noch ging, weil am Schlossplatz eine Bahn entgleist war.

Zur langen Nacht der Museen muss immer etwas passieren, wie etwa vor zwei Jahren, als das Parkhaus uns nicht rausließ.

Dieter-Hamann-Bridge

Leider ohne ursprünglichen Autor, soeben in meinem Mailkasten gelandet:

"Engländer ärgern - macht alle mit!!!

Hallo, das ist doch der Spaß wert ;-)

Wer erinnert sich nicht an das glorreiche 1:0 der deutschen Fußball-Nationalmannschaft im letzten Spiel vor dem Abriss des altehrwürdigen Wembley-Stadions? (Wie sehr die Engländer diese Niederlage geschmerzt hat, lässt sich übrigens gut in David Beckham "My Side" nachlesen.)

Nun ist es an der Zeit, Didi Hamann für seinen Sieg-Freistoß (ca. 25 Meter Entfernung, flach über den nassen Rasen ins untere linke Eck!) entsprechend zu würdigen: Mittlerweile ist das Wembley-Stadion wieder aufgebaut und zum Stadion führt eine neue Brücke, die noch namenlos ist. Deswegen hat die London Development Agency einen Wettbewerb ausgeschrieben, bei dem der Name gewinnt, der am häufigsten genannt wird. Und das ist unsere Chance!

Also hier für "Dietmar-Hamann-Bridge" voten:
http://www.lda.gov.uk/server.php?show=ConForm.9

In der Begründung bitte angeben: 'In tribute to the player who scored the last goal in the old stadium'

P.S. Schickt den Link mal an alle Freunde und Bekannte und/oder stellt ihn in die bekannten und internen Foren - wäre doch gelacht wenn wir die Tommies nicht noch ein bisschen Ärger könnten."

Da mach' ich mit!

What's DLP?

OWL has some sublanguages which are all more or less connected to each other, and they make the mumbojumbo of ontology languages not any clearer. There is the almighty OWL Full, there's OWL DL, the easy* OWL Lite, and then there are numerous 'proprietary' expansions, which are more (OWL-E) or less (OWL Flight) compatible and useful.

We'd like to add another one, OWL DLP. Not because we think that there aren't enough already, but because we think this one makes a difference. Because it has some nice properties, like fully translatable to logic programs, and because it is easy to use and because it is fully compatible to standard OWL, and you don't have to use any extra tools.

If you want to read more, I and some colleagues at the AIFB wrote a short introduction to DLP (and the best thing is: if I say short, I mean short. Just two pages!). It's meant to be easy to understand as well - but if you have any comments on that, please provide them.

 * whatever easy means here

Gutes Karma

Tibetanische Buddhisten glauben, dass das benutzen des Mantras OM MANI PADME HUM die sechs bösen Geister Stolz, Eifersucht, Lust, Unwissen, Gier und Wut vertreibt und die sechs guten herbeiruft, Großzügigkeit, Harmonie, Ausdauer, Begeisterungsfähigkeit, Konzentration und Einsicht.

Statt das man das Mantra selber meditiert, kann man es aber auch auf eine sogenannte Gebetsmühle eintragen. Eine Umdrehung der Gebetsmühle wirkt wie die einmalige Rezitation des Mantras. Gebetsmühlen haben außerdem den Vorteil, dass man das Mantra mehrfach aufmalen kann: 10 mal geschrieben, einmal gedreht, 10 mal Wirkung.

Heute geht das alles viel schneller und effizienter. Moderne Festplatten drehen sich mit ein paar tausend Umdrehungen pro Minute. Das heißt, wenn man ein Gebetsmantra runterlädt und auf der Festplatte abspeichert, dann wirkt das Mantra mit der Zeit ganz automatisch und mit geballter Kraft - viel stärker, als ein Mensch es herbeten könnte.

Mehr Infos zur digitalen Gebetsmühle (engl.).

Social tagging und Co

Cool. Ich sei im Januar Inspiration für diesen Blogeintrag zu Social Tagging mit del.icio.us, flickr und ähnlichem gewesen. Scheint, als hätte ich meine Arbeit nicht soo schlecht gemacht... (und dabei war ich nach genau dieser ersten Sitzung davon überzeugt, dass ich grottig gewesen sei. Aber das bin ich ja von eigener Arbeit zunächst immer...)

New versions: owlrdf2owlxml, dlpconvert

New versions of owlrdf2owlxml and dlpconvert are out.

owlrdf2owlxml got renamed, as it was formerly known as rdf2owlxml. But as a colleague pointed out, this name can easily be misunderstood, meaning to transform arbitrarily RDF to OWL. It doesn't do that, it only transforms OWL to OWL, from RDF/XML-serialisation to XML Presentation Syntax. And it seems to work quite stable, it can even transform the famous wine ontology. Version 0.4 out now.

dlpconvert lost a lot of its bugs. And as most of you were feeding RDF/XML to it, well, now you can do it officially (listen to the users), too. It reads both syntaxes, and creates a Prolog program out of your ontology. Version 0.7 is out.

They are both based on KAON2, the Karlsruhe Ontology Infrastructure module, written by Boris Motik. My little tools are just wrapped around KAON2 and using its functionality. To be honest, I'm thinking of writing quite a number of little tools like this, who offer different functionality, thus providing you with a nice toolkit to handle ontologies efficiently. I don't lack ideas right now, it's just I' m not sure that there's interest in this.

Well, maybe I should just start and we'll see...

By the way, both tools are not only available as web services, but you may also download them as command line tools from their respective websites and play around it on your PC. That's a bit more comfortable than using a browser as your operating system.

200.000

Yeah. Heute Nacht hat der Counter den 200.000. Besucher der Nodix-Seiten erwischt. Danke an all die Besucher über die Jahre hinweg!

Der Googlecount auf die Suchbegriffe der letzten zwei Blogs ist weiter rückläufig: 28,100 / 36,100 / 667. Das bedeutet besonders bei dem letzten Begriff einen Unterschied von weit über 500%!

Google ändern

Huch? Seit gestern haben sich für die dort angegeben Suchen die Anzahl der Hits gewaltig gesenkt. Heute sieht es so aus:

geruch der luft nach regen: 28,200 Treffer
gefühl von schnee auf der haut: 36,600 Treffer
eigene wahrnehmung von dem gefühl von schnee auf der haut: 1,140 Treffer

Hmmm. Wahrscheinlich benutzen se ein approximate Reasoning Algorithmus für die erste Näherung, und, bei mehrfacher Wiederholung machen sie wahrscheinlich dann eine genauere Rechnung auf, die gecacht wird.

Oder so.

Es ist nicht real, wenn es nicht im Internet ist

Eben im ICQ...

Buddy: ich weiß, was man nicht im internet findet, kann nicht real sein
Buddy: ;)
denny: man findet etwas nicht im internet?
denny: was?
Buddy: der geruch der luft nach regen
Buddy: das gefühl von schnee auf der haut
Buddy: etc.
denny: warte mal
Buddy: oh bitte, du googlest doch nicht etwa danach...
denny: geruch der luft nach regen: 38,400 treffer
denny: gefühl von schnee auf der haut: 57,800 treffer
Buddy: ja, du findest die beschreibung anderer davon, aber nicht die eigene wahrnehmung
denny: eigene wahrnehmung von dem gefühl von schnee auf der haut: 3,620 treffer

Unexpected problems

As you know, I'm a strong believer in the vision of the Semantic Web, and I actively pursue this goal. I am not too sure what it means, but I have hundreds of ideas floating through my head, about what will be possible in this future...

But the road seems longer than expected. For some time I have the dlpconvert and rdf2owlxml web services running. It is very enlightening and interesting to see, what kind of ontologies were used for testing. And I most certainly don't mean the domain of the ontologies used, but rather the syntax.

Both services state very clearly what syntaxes you may use. dlpconvert allows only OWL XML presentation syntax, rather obscure, I admit. That's the main reason, rdf2owlxml was offered. But most people didn't care, they just keep on using RDF - and not just OWL in RDF/XML-serialisation, but much more simple, plain RDF.

Yeah, every RDF is in OWL Full. But dlpconvert only deals with OWL DL. That's stated explicitly. And much less does it work with Abstract Syntax or N3. All of this was tested.

I most definitively don't want to rant about users here. You never should rant about users (I mean, in public). Especially, since everyone who uses a service like dlpconvert is probably quite intelligent and has some expertise in the field of Semantic Web. It's not his fault. It isn't mine either, I wrote quite explicitly what is needed. Maybe it's the W3Cs fault, or maybe it's just to blame on politics.

The fine differences between RDF, RDFS, RDF(S), OWL, OWL Full, OWL DL, OWL Lite, DLP - yes, I said fine differences between RDF and OWL DL - it's just too much to cope with. If it is too much for us, what do we expect of the future user of the Semantic Web? The web as we know it grew to its todays size because it was easy. It wasn't because of standards. For the first few years no one really cared about the HTML standard, I mean, not to the extent we do today in the Semantic Web. Even with tons of errors, pages would load and show nice results. It was a very forgiving system. And now, find out why it was so widely adopted?

The problem is: maybe we really need to be as strict as we are. But I hope we don't. I strongly believe into the virtue of "View source" - but this means understandable views on the source. Not RDF/XML-Serialisation. And still easy to copy. Only this way the Semantic Web can lift off from the roots, from the users. The users were creating the Web in the first years, not the companies. I don't know why everybody is turning to the companies today.

Oh, I should stop, it sounds like ranting again.

Pendeln

"Und, pendelst Du immer noch?"
"Na ja, eigentlich lege ich eher Tarot-Karten als zu pendeln, aber manchmal schon."
"Ich meinte zur Arbeit."

Danke für die Heimfahrt!

Wodka

Neulich, im Getränkemarkt...

"Oh, wir könnten noch Bananen- und Kirschsaft kaufen, für KiBa."
"Coole Idee. Das sind zwei Flaschen Banane und eine Flasche Kirsch."
"Nö, das mischt man 1:1. Wir nehmen zwei von jeder."
"Echt? Na gut."
"Oh, schau, Mangosaft! Nehmen wir auch eine Flasche Mangosaft."
"Soviel passt aber nicht in die Kiste. Wir müssen was raustun."
"Hier, nehmen wir nur eine Flasche Banane."
"Aber dann haben wir ja zwei Flaschen Kirsche auf nur eine Flasche Banane."
"Ja und?"
"Du sagtest doch, die mischt man 1:1."
"Ja, schon, aber den Kirschsaft kann man auch für anderes hernehmen."
"Ach ja? Für was denn?"
"Kirsch Wodka zum Beispiel."
"Wir haben Wodka da?"
"Nein."
"..."
"Blogg das bitte nicht!"

Glaubst Du doch selbst nicht. Wer solche Bilder von mir bloggt, der hat kaum Gnade verdient... ;)

Valentinstag

Warum gibt es eigentlich die Valentinsgrußkarte "Ich liebe nur Dich!" auch im Fünferpack?

Die Hasselhof-Rekursion

Achtung! Schäden für das Gehirn sind nicht ausgeschlossen.

Wer hier klickt, ist selber schuld.

Ironie

Ein militanter Gegner des Gesetzes zum verpflichtenden Anschallen mit dem Sicherheitsgurt beim Autofahren stirbt bei einem Autounfall.

Flop of the Year?

IEEE Spectrum Editor Steven Cherry wrote the article Digital Dullard in, well, IEEE Spectrum. Well, he obviously dislikes Paul Allen for his money, and can't stop ranting about him, and about Mr Allen spending millions and millions of Dollars in research projects ("that's just the change that drops down behind the sofa cushions"). Yeah, Mr Cherry, you're totally right - why should he spend more than 100 Million Dollars in research, he should rather invest it in a multi-million house, an airline or produce a Hollywood blockbuster with James Cameron.

The thing is, Cherry claims the whole project of creating a Digital Aristotle, dubbed Project Halo, is naught but thrown out money, because understanding a page of chemistry costs about 10.000$. For one single page! Come on, how many students would learn one page for 10.000$?

Project Halo succeeded in creating a software program that is capable of taking a high school advanced-placement exam in chemistry, and actually, to pass the exam - and it did, and even beating the average student in it. Millions have been spent, says Cherry, for that? Wow...

Cherry fails to recognise two points here, that illustrate the achievement of such a project:

First, sure, it may cost 10.000$ to get a program that understands one page, and it may cost only 20$ to get a human to do the same. So, training a program that is able to replace a human may cost millions and millions, whereas training a human to do so will probably cost a mere few ten thousands of dollars. But ever considered the costs of replication? The program can be copied for an extremely low cost of a few hundred bucks, whereas every human costs the initial price.

Second, even though the initial costs of creating such prototype programs may be extremely high, that's no reason against it. Arguments like this would have hindered the development of the power loom, the space shuttle, the ENIAC and virtually all other huge achievements in engineering history.

It's a pity. I really think that Project Halo is very cool, and I think it's great, Mr Allen is spending some of his money on research instead of sports. Hey, it's his money anyway. I'd thank him immediately if I should ever meet him. The technologies exploited and developed there are presented in papers and thus available to the public. They will probably help in the further development and raise of the Semantic Web, as they are able to spend some money and brain on designing usable interfaces for creating knowledge.

Why do people bash on visions? I mean, what's Cherry's argument? I don't catch it... maybe someone should pay me 20.000$ to understand his two pages...

Introducing rdf2owlxml

Very thoughtful - I simply forgot to publish the last entry of this blog. Well, there you see it finally... but let's move to the new news.
Another KAON2 based tool - rdf2owlxml - just got finished, a converter to turn RDF/XML-serialisation of an OWL-ontology into an OWL/XML Presentation Syntax document. And it even works with the Wine-ontology.

So, whenever you need an ontology in the easy to read OWL/XML Presentation Syntax - for example, in order to XSL it further to a HTML-page representing your ontology, or anything like that, because it's hard to do this stuff with RDF/XML, go to rdf2owlxml and just grab the results! (The results work fine with dlpconvert as well, by the way).

Hope you like it, but be reminded - it is a very early service right now, only a 0.2 version.

Released dlpconvert

There's so much to do right now here, and even much, much more I'd like to do - and thus I'm getting a bit late on my announcements. Finally, here we go: dlpconvert is released in a 0.5 version.

You probably think: what is dlpconvert? dlpconvert is able to convert ontologies, that are within the dlp-fragment, from one syntax - namely the OWL XML Presentation Syntax- into another, here Datalog. Thus you can just take your ontology, convert it and then use the result as your program in your Prolog-engine. Isn't that cool?

Well, it would be much cooler if it were stronger tested, and if it could read some more common syntaxes like RDF/XML-Serialisation of OWL ontologies, but both is on the way. As for testing I would hope that you may test a bit - as for the serialisation, it should be available pretty soon.

dlpconvert is based totally on KAON2 for the reduction of the ontology.

I will write more as soon as I have more time.

Vier Jahre Nodix (und kein bisschen weißer)

Am 14. Januar eröffnete Nodix - meine zweite Website nach einem Vorgänger in den frühen 90ern - die Pforten, und vieles, vieles hat sich seitdem getan. Ein halbes Dutzend eigener Websiten ist aus Nodix seitdem entstanden, und noch ein paar sind geplant, die mehr oder weniger ein kleines Netzwerk von Websiten bilden sollen.

Im ersten Jahr wahr ich sehr stolz, 2.000 Besucher gehabt zu haben. Irre! Größenwahnsinnig startete ich die Aktion 10.000, bis Januar 2003 10.000 Besucher gehabt zu haben - und tatsächlich es gelang, sogar schon bis August 2002. 2002 hatte Nodix insgesamt 20.000 Besucher - eine unglaubliche Verzehnfachung! 2003 wurde die Zahl nochmal mehr als verdoppelt - 44.000 Besucher in jenem Jahr. Und 2004 schließlich, bis heute, hatten über 115.000 Besucher! Für eine private Homepage wirklich famos. Vielen Dank all den Leuten, die Nodix treu sind, und es ab und an besuchen.

Allerdings hat sich in den Jahren auch ein kleines Team um Nodix gebildet. Nicht, dass es sich selber so bezeichnen würde, aber große Teile von Nodix entstehen und entstanden unabhängig voneinander. Jüngster Sproß ist Schwesterchens nakit-arts, das lange nur ihre Galerie enthielt, jetzt aber mit ihrem Blog - einem der schönsten überhaupt - zu den bestbesuchten Seiten hier gehört. Desweiteren Ralf Baumgartner, der, obwohl er eine eigene Website hat, sich demnächst verstärkt um something*positive kümmern wird, einer der Dornröschen-Seiten von Nodix. Genau wie die nutkidz. Doch für beide ist geplant, in den nächsten Wochen sie wiederzubeleben, und die Pläne schreiten voran. Versprochen, nichts davon stirbt.

Dies gilt insbesondere für das DSA4 Werkzeug, das zur Zeit leider nicht einmal eine Website hat. Twel wird sich hier verstärkt darum kümmern, doch es hängt an mir. Zu meinen guten Vorsätzen und Plänen dieses Jahr gehört es aber, einige Aufgaben endlich abzuschließen: dazu gehört zunächst das Verfassen zweier Texte für DSA, einer fast fertig, einer in Planung; und dazu gehört der Relaunch der Website zum und das Fertigstellen des DSA4 Werkzeugs. Ja, genau gelesen, mein Zeitplan für 2005 sieht eine fertige Version des DSA4 Werkzeugs vor - definiert als über 95%-ige Regelkonformanz bei der Generierung und Steigerung. Na, ist das nichts?

So weit zu den Versprechungen und Plänen. Und was hat es mit dem Weißer auf sich? Nun, wie seit dem ersten Tag ist die Hintergrundfarbe von Nodix, einer weltbekannten Spielefirma zu Ehren, eaeaea.

Comments to naming

Richard Newman sent me some thoughtful comments via eMail on the What's in a name series (there were also some great comments on the individual entries, feel free to browse them). He sent them via eMail, cause he thought he couldn't comment - that should be wrong, everyone should be able to comment anonymously. Or did anyone else encounter problems? I should switch to some dedicated software soon, anyway, but right now I don't have the time to dig deeper into it. I especially miss trackback, sigh.

Here's what Richard wrote:

"Your first point, about ISBNs and "what's being referenced" --- I think you'd be interested in FRBR, which is a modelling of the bibliographical domain. It splits things up into

Work -> Expression -> Manifestation -> Item

A work is an abstract concept, like "Politeia". An expression is a realisation of a work, so a particular translation is an expression. A manifestation is physical embodiment of an expression: this is what's given an ISBN. All copies of a certain book are Items; the edition of the book is their Manifestation.

So, you see, when you're discussing Plato's Politeia, you have to be conceptually clear about whether you're talking about works, expressions, manifestations, or items.

E.g.

:PolWork dc:creator "Plato" ;
  rdfs:label "Plato's Politeia, the abstract concept." .
:PolExp1 ex:translator "Mr Smith" ;
  frbr:work :PolWork ;
  rdfs:label "Mr. Smith's translation of Plato's Politeia." .
:PolMan1 ex:publisher "Penguin" ;
  frbr:expression :PolExp1 ;
  rdfs:label "Penguin's edition of Smith's translation." .
:MyCopy ex:owner hg:RichardNewman ;
  frbr:manifestation :PolMan1 ;
  rdfs:label "Richard's copy of the Penguin edition." .

Do you see? Each level has its own properties (and some may be duplicated; e.g. each has a title: the title of the abstract work, the name given to the translation, the name Penguin prints on each book, and the name printed on my copy).

I've done a bit of work on modelling FRBR in RDFS/OWL, but haven't yet finished. "

I think that's really interesting, and taking a look at FRBR it was pretty well done. I sure am looking forward to see Richards interpretation in OWL, and will probably use it.

"Your second issue is the difference between a resource and its representation. A URI should only refer to one thing; it is entirely wrong to use http://www.holygoat.co.uk to refer both to my homepage (as in using RDF to describe its language, or size, or last-modified) and to me (my name, my email address, etc.) which I have seen done.

Your web server should return RDF for http://semantic.nodx.net/#Plato if your browser says that it accepts RDF+XML. A normal browser should have an HTML representation returned. Indeed, it's possible to do the following:

• the abstract resource. Hit this with a browser, get an HTML page; with an RDF agent, get some RDF.

http://example.com/Plato a rdf:resource .

• the HTML representation.

http://example.com/Plato/html a ex:representation ;
  ex:representationOf http://example.com/Plato .

• 1. the RDF.

http://example.com/Plato/rdf a ex:representation ;
  ex:representationOf http://example.com/Plato .

i.e. you can unambiguously refer to each representation, and the resource. When your client arrives, asking for Plato, you can redirect them to the appropriate place. Clever, huh?

URIs should never give a 404. They should return the appropriate headers or content for whatever the client is requesting; this may be the RDF file in which the resource is defined, if the client understands RDF, or an HTML page.

If you're interested in this sort of thing, it pops up on the W3C's RDF Interest Group list occasionally.

Patrick Stickler and others have come up with an additional HTTP verb, MGET, which will return the RDF description of a resource. Combined with their URIQA architecture, it will give you a Concise Bounded Description for a URI. This stops you having to somehow put descriptions into particular files, and better deals with the distributed nature of the Semantic Web. Check it out; it presents several convincing arguments for not using fragment identifiers to refer to resources, and solves your bandwidth problem. You should never have to dump a whole file to get a description of a URI."

I have to note that Richard wrote me this just after part 4 of the series was published, so I could answer some of the questions already in the last two parts. Just to summarise it: I don't like content negotiation. Although it is technically totally feasible, I disagree that it should be done or is a good solution. If my browser asks for http://semantic.nodix.net/#Plato I don't think I should get different things depending on the content negotiation. This feels like cheating.

I wrote that to Richard already, and he answered:

"I think we agree on the main point, which is that

foaf:name "Richard" ; ex:format "HTML" .

which is a travesty :) "

He is totally right here.

"You still see it happen, though, with people referring to Wikipedia pages as if they were the abstract resource.

The content negotiation (getting different things depending on what you accept) is exactly what the Web is supposed to do. If I'm using a mobile browser, I want a simplified version of a page; if I'm an RDF agent, I want RDF, if it exists, because HTML is of no use to me. A common usage of this is to serve up strict XHTML to Mozilla, and less-strict HTML to Internet Explorer. It is also done all the time to serve PNG where the client accepts it, and GIF if it doesn't, and there is an intentional disconnect on the Web between a resource and its representations.

The lack of such a disconnect would lead to exactly the problem you describe; if I can't return a representation of a resource, because it's abstract, then how do I find out anything about it? I could use MGET, but you can't MGET a person... so, if you want to talk about the real world thing "Plato", he has to 404, or you get the "what am I talking about?" problem. Better, in my view, to redirect a browser to plato.html and a SW agent to a chunk of RDF. "

I would rather like to ask for http://semantic.nodix.net/Plato.rdf to get the RDF/XML representation, http://semantic.nodix.net/Plato.owl to get the OWL/XML representation, http://semantic.nodix.net/Plato.html to get a HTML page for the user to read and for a picture of Plato. This shouldn't be hidden behind content negotiation. I know, I know, Patrick would strongly disagree here, but I think it feels wrong and actually defies the idea of an URI.

"You can do exactly that (and I agree that the representations should have separate URIs --- conneg is only for when you're trying to get some description of an abstract resource), but then how do you refer to the abstract concept of "Plato"? http://.../Plato is a resource, and I want to make statements about him. But there's no point in it being 404 when dereferenced, because then how would I find out that Plato.html exists? HTTP doesn't return URIs, it returns representations of them.

A URI is simply something that is dereferenced to get a representation, and that representation should be decided on by conneg. In this case, /Plato is an abstract resource, so one of the representations should be returned. We can then make statements about Plato (e.g. foaf:name "Plato"), and about the JPEG and HTML representations, because they have different URIs, but still get something useful back when we want to access /Plato."

I also dislike MGET right now. Maybe I am wrong, but to me, the whole URIQA architecture feels somewhat wrong - but maybe I should just dwell deeper into it, I have to admit, I didn't study it yet enough to really be in a position to bash on it. The problem is, that MGET seems unnecessary to me - and it works on a different conceptual level than the rest of the Semantic Web proposals. I think everything MGET solves can be solved with tools that already exist: Richards example above, where he gives triples telling us which representations are used to describe a resource, shows perfectly well that you actually don't need content negotiation and MGET.

"There are things to question about URIQA, but it does have some good going for it. MGET is actually an implicit query. In the standard Web model, you request URIs and get back document representations. Doing an MGET on a Web server is asking it to return a description, regardless of where on the site descriptions of that resource exist, and you're explicitly asking for meta-data. As Patrick points out, it's similar doing a GET and specifying that you accept RDF, but is likely to be more concise (the difference between a "representation" and a "description"). In fact, this is exactly what the Nokia URIQA server does.

MGET overlaps with query servers a bit, and with GET a bit, but it's a little bit special, too. The whole idea is that from a single URI you can get a useful description of a resource, just by issuing a single MGET. Every other approach needs more work."

This URIQA / MGET stuff sounds more and more interesting. I really should dwell deeper into it.

Also, the idea of Concise Bounded Descriptions may be very neat, I have to study that more as well. Funny thing, the very same day Richard pointed me to it, a colleague told me about it too - this is usually a sign, that this idea is worth considering more.

Richard also wrote "URIs should never give a 404", and as you know, I disagreed with it mildly. He tried to summarise his position:

"I consider that each returned resource should have its own URI --- e.g. Plato.jpg --- and that the original URI should be used to make statements about the abstract resource. This allows you to say

...Plato foaf:name "Plato" .
...Plato.jpg ex:resolution "150dpi" .
...Plato.html dc:creator "Denny" .

Dereferencing the abstract resource, rather than throwing a 404, should do something useful --- e.g. redirecting with a 303 to one of the representations. Have you ever tried viewing a Blogger Atom feed in your browser? If you hit it with an RSS reader, you get the XML, but in a browser Blogger shows you an XHTML transformation of the XML. That's useful, and I think that's how the Semantic Web should work. Imagine if your agent hit /Plato, and got RDF out of it, but when you looked at it with your browser you saw a dynamically-generated HTML page? Handy!

I can understand your objection, though; it does seem wrong that you get different things out of the same URI. However, you should almost always get HTML out of plato.html, and RDF out of plato.rdf. All the conneg is doing is making sure you can see an abstract thing in the best way possible, according to what you've told the server you can understand. "

Richard is pretty good in convincing me, cause he uses the right arguments: it's for the people, dummy, and the machines can work it out anyway.

I still stick to the recommendations I gave yesterday. But just as I am writing, and rereading it all, I am starting to change my mind on content negotiation. Maybe it is a good thing. I will have to think about it some more, and as soon as I come to a solution, I will bother you with it again. I still have a gut feeling about it that tells me 'no', but the reasons given sound very convincing and I agree with most of them, so heck, let's meditate on this as soon as I find a few hours to spare.

Big thanks to Richard and his thoughts, anyway. I hope this discussion helps you to make up your own mind as well.

What's in a name - Part 6

In this series we learned how to make URIs for entities. I know there's a big discussion flaring up every few weeks or so, if we should use fragment identifier or not. For me, this question is pretty much settled. Using a fragment identifier has the advantage of giving you the ability of providing a human readable page for those few lost souls who look up the URI, so maybe it's a tad nicer than using no fragment identifier and returning 404s. Not using fragids has the advantage of probably reducing bandwidth - but this discussion should be more or less academic, because looking up URIs, as we have seen, should not happen.

There is some talking about different representations, negotiating media-types, returning RDF in one, XHTML in the other case, but to be honest, I think that's far too complicated. And you would need to use another web server and extensions to HTTP to make this real, which doesn't really help the advent of the Semantic Web. Look at Nokias URIQA project for more information.

Keep this rules in mind, and everything should be fine:

• be careful to use unused URIs if you reference a new entity. Take one from an URI space you have control of, so that URI collision won't appear
• don't put a website under the URI you used to to name an entity. That would lead to URI collision
• try to make nice looking URIs, but don't try to hard. They are supposed to be hidden by the application anyway
• provide rdfs:label and rdfs:seeAlso instead. This solves everything you would want to try to solve with URI naming, but in a standard compliant way
• give your resources URIs. Please. So that other can reference them more easily.

I should emphasise the last one more. Especially using RDF/XML-Syntax easily leads to anonymous nodes, which are a pain in the ass because they are hard or impossible to address. Especially, don't use rdf:nodeID. They don't give your node an ID that's visible to the outer world. This is just a local name. Don't use it, please.

The second is using them like this:

<foaf:person about="me">
  <foaf:knows>
    <foaf:Person>
      <foaf:name>J. Random User</foaf:name>
    </foaf:Person>
  </foaf:knows>
</foaf:Person>

Actually, the Person known to "me" is an anonymous one. You can't refer to her. Again, try to avoid that. If you can, look up the URI the person gave to herself in her own FOAF-file. Or give her a name in your own URI-space. Don't be afraid, you won't run out of it.

Another very interesting approach is to use published subjects. I will return to this in another blog, promised, but so long: never forget, there is owl:sameAs to make two URIs point to the same thing, so don't mind too much if you doublename something.

Well, that's it. I hope you enjoyed the series, and that you learned a bit from it. Looking forward to your comments, and your questions.

What's in a name - Part 5

After calling Plato an XML-Element, making movies out of websites and having several accidents with careless URIs, it seems we return to the very beginning of this series.

http://semantic.nodix.net/document/Politeia dc:creator "Plato".

Whereby http://semantic.nodix.net/document/Politeia explicitly does not resolve but returns a 404, resource not found. Let's remember, why didn't we like it? Because humans, upon seeing this, have the urge to click on it in order to get more information about it. A pretty good argument, but every solution we tried brought us more or less trouble. We didn't get happy with any of them.

But how can I dismiss such an argument? Don't I risk loosing focus with saying "don't care about humans going nowhere"? No, I really don't think so. Due to two reasons, one meant for humans and one for the machines.

First the humans (humans always should go first, remember this, Ms and Mr PhD-student): humans actually never see this URI (or at least, should not but when debugging). URIs who will grace the GUI should have a rdfs:label which provides the label human users will see when working with this resource. Let's be honest: only geeks like us think that http://semantic.nodix.net/document/Politeia is a pretty obvious and easy name for a resource. Normal humans would probably prefer "Politeia", or even "The Republic" (which is the usual name in English speaking countries). Or be able to define their own name.

As they don't see the URI, they actually never feel the urge to click on it, or to copy and paste it to the next browser window. Naming it http://semantic.nodix.net/document/Politeia instead of http://semantic.nodix.net/concept/1383b_xc is just for the sake of readability of the source RDF files, but actually you should not derive any information out of the URI (that's what the standard says). The computer won't either.

The second point is, a RDF application shouldn't look up URIs either. It's just wrong. URIs are just names, it is important that they remain unique, but they are not there for looking up in a browser. That's what URLs are for. It's a shame they look the same. Mozilla realised the distinction when they gave their XUL language the namespace http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul. Application developers should realise this too. rdfs:seeAlso and rdfs:isDefinedBy give explicit links applications may follow to get more information about a resource, and using owl:imports actually forces this behaviour - but the name does not.

Getting information out of names is like making fun of names. It's mean. Remember the in-kids in primary school making fun of out-kids because of their names? You know you're better than that (and, being a geek, you probably were an out-kid, so mere compassion and fond memories should hold you back too)..

Just to repeat it explicitly: if an URI gives back a 404 when you put it in a browser navigation bar - that's OK. It was supposed to identify resources, not to locate them.

Now you know the difference between URIs and URLs, and you know why avoiding URI collision is important and how to avoid it. We'll wrap it all in the final instalment of the series (tomorrow, I sincerely hope) and give some practical hints, too.

By the way, right after the series I will talk about content negotiation, which was mentioned in the comments and in e-Mails.

Uh, and just another thing: the wary reader (and every reader should be wary) may also have noticed that

Philosophy:Politeia dc:creator "Plato".

is total nonsense: it says, that there is a resource (identified with QName Philosophy:Politeia) that is created by "Plato". Rest assured that this is wrong - no, not because Socrates should be credited as the creator of the Politeia (this is another discussion entirely) but because the statement claims that the string "Plato" created it - not a Person known by this name (who would be a resource that should have an URI). But this mistake is probably the most frequent one in the world of the Semantic Web - a mistake nevertheless.

It's OK if you make it. Most applications will cope with it (and some are actually not able to cope with the correct way). But it would not be OK if you didn't know that you are making a mistake.

What's in a name - Part 4

I promised you four solutions to the problem of dubbing with appropriate URIs. So, without further ado, let's go.

The first one you've seen already. It's using anonymous nodes.

_person foaf:interest _security.
http://dmoz.org/Computers/Security/ dc:subject _security.

But here we get the problem, that we can't reference _security from outside, thus loosing a lot of the possibilities inherent in the Semantic Web, because this way you can not say that someone else is interested in the same topic as _person above. Even if you say, in another RDF file,

_person2 foaf:interest _security.
http://dmoz.org/Computers/Security/ dc:subject _security.

_security actually does not have to be the same as above. Who says, websites only have one subject? The coincidental equality of the variable name _security bears as much semantics as the equality of two variables x in a C and a Python-Program.
So this solution, although possible, bears too much short-comings. Let's move on.

The second solution is hardly available to the majority of us puny mortals. It's introducing a new URI schema. Let's return to our very first example, where we wanted to say that the Politeia was written by Plato.

urn:isbn:0192833707 dc:creator "Plato".

Great! No problems here. Sure, your web-browser can't (yet) resolve urn:isbn:0192833707, but no ambiguity here: we know exactly of what we speak.

Do we? Incidentally, urn:isbn:0465069347 also denotes the Politeia. No, not in another language (those would be another handful of ISBN numbers), just a different version (the text is public domain). Now, does the following statement hold?

urn:isbn:0192833707 owl:sameAs urn:isbn:0465069347.

Most definitively not. They have different translators. They have different publishers. These are different books. But it's the same - what? What is the same? It's not the same text. It's not the same book. They may have the same source text they are translated from. But how to express this correctly and still useful?

The urn:isbn: scheme is very useful for a very special kind of entities - published books, even the different versions of published books.
The problem with this solution that you would need tons of schemes. Imagine the number of committees! This would, no, this should never happen. We definitively need an easier solution, although this one certainly does work for very special domains.

Let's move on to the third solution: the magic word is fragment identifier. #. Instead of saying:

http://semantic.nodix.net/Politeia dc:creator http://semantic.nodix.net/Plato.

and thus getting 404s en masse, I just say:

http://semantic.nodix.net/#Politeia dc:creator http://semantic.nodx.net/#Plato.

See? No 404. You get to the homepage of this blog by clicking there. And it's valid RDF as well. So, isn't it just perfect? Everything we wished for?

Not totally, I fear. If I click on http://semantic.nodx.net/#Plato, I actually expect to read something about Plato, and not to see a blog about the Semantic Web. So this somehow would disappoint me. Better than a 404, still...
The other point is my bandwidth. There can be RDF files with thousands of references. Following every single one will lead to considerable bandwidth abuse. For naught, as there is no further information about the subject on the other side. Maybe using http://semantic.nodix.net/person#Plato would solve both problems, with http://semantic.nodix.net/person being a website saying something like "This page is used to reserve conceptual space for persons. To understand this, you must understand the magic of URIs and the Semantic Web. Now, go back whereever you came from and have a nice day." Not too much webspace and bandwith will be used for this tiny HTML-page.

You should be careful though to not have a real fragment identifier "Plato" in the page, or you would actually dereference to this element. URI collision again. You don't want Plato to become half-philosopher / half-XML-element, do you?

We will return to fragment identifiers in the last part of this six part series again. And now let's take a quick look at the fourth solution - we will discuss it more thoroughly next time.

Use a fresh URI whenever you need an URI and don't care about it giving a 404.

What's in a name - Part 3

Last time we merrily published our first statement for the Semantic Web:

http://www.imdb.com/title/tt0088247/ http://purl.org/dc/elements/1.1/creator "James Cameron".

A fellow Semantic Web author didn't like the number-encoded IMdb-URI, but found a much more compelling one and then published the following statement:

http://en.wikipedia.org/wiki/The_Terminator http://purl.org/dc/elements/1.1/date "1984-10-26".

A third one sees those and, in order to foster integration of data offers helpfully the following statement:

http://www.imdb.com/title/tt0088247/ owl:sameAs http://en.wikipedia.org/wiki/The_Terminator.

And now they live merrily ever after. Or do you hear the thunder of doom rolling?

The problem is that the URIs above actually already denote something, namely the IMdb website about the Terminator and the Wikipedia-article on the Terminator. They did not denote the movie itself, but that's how they're used in our examples. Statement #3 above actually says the two websites are the same. The first one says, that "James Cameron" created the IMdb website on the Terminator (they'd wish), and the second one says that the Wikipedia article was created in 1984, which is wrong (July 23, 2001 would be the correct date). We have a classic case of URI collision.

This happens all the time. People working professionally on this do this too:

_person foaf:interest http://dmoz.org/Computers/Security/.

I'd bet, _person (remaining anonymously here) does not have such a heavy interest in the website http://dmoz.org/Computers/Security/, but rather in the Topic the website is about.

_person foaf:interest _security.
http://dmoz.org/Computers/Security/ dc:subject _security.

Instead of letting _security be anonymous, we'd rather give it a real URI. This way we can reference it later.

_person foaf:interest http://semantic.nodix.net/topic/security.
http://dmoz.org/Computers/Security/ dc:subject http://semantic.nodix.net/topics/security.

But, oh pain - now we're exactly at the same spot we've been in the last part. We have an URI that does not dereference to a website (by the way, I do know that the definition of foaf:interest actually says the semantics of foaf:interest is, that the Subject is interested in the Topic of the Object, and not the Object itself, but that's not my point here)
Thinking for a moment about it, we must conclude that it is actually impossible to achieve both goals: either the URIs will identify a resource retrievable over the web and are thus unsuitable as URIs for entities outside the web (like persons, chairs and such) because of URI collision, or they don't - and will then lead to 404-land.

Isn't there any solution? (Drums) Stay tuned for the next exciting installment of this series, introducing not one, not two, not three, but four solutions to this problem!

What's in a name - Part 2

How to give a resource a name, an URI? Let's look at this statement:

movie:Terminator dc:creator "James Cameron".

Happy with that? This is a valid RDF statement, and you understand what I wanted to say, and your RDF machine will be able to read and process it, too, so everything is fine.

Well, almost. movie:Terminator is a QName, and movie: is just a shorthand prefix, a namespace, that actually has to be defined as something. But as what? URIs are well-defined, so we shouldn't just define the namespace arbitrarily. The problem is, someone else could do the same, and suddenly, one URI could denote two different resources - this is called URI collision, and it is the next worst thing to immanentizing the Eschaton. That's why you should grab some URI space for yourself and there you go, you may define as many URIs there as you like (remember, the U in URI means Universal, that's why they make such a fuss about the URI space and ownership of it).

I am the webmaster of http://semantic.nodix.net, and the URI belongs to me and with it, all the URIs starting with it. Thus I decide, that movie: shall be http://semantic.nodix.net/movie/. Our example statement thus is the same as:

http://semantic.nodix.net/movie/Terminator http://purl.org/dc/elements/1.1/creator "James Cameron".

So this is actually what the computer sees. The short hand notation above is just for humans. But if you're like me, and you see the above Subject, you're already annoyed that it is not a link, that you can't click on it. So you copy it into your browser address bar, and go to http://semantic.nodix.net/movie/Terminator. Ups. A 404, the website is not found. You start thinking, oh man, stupid! Why you giving the resource such a name that looks so much like an web address, and then point it to 404-Nirvana?

Many think so. That's because they don't grasp the difference between URIs and URLs, and to be honest, this difference is maybe the worst idea the W3C ever had (that's a hard-to-achieve compliment, considering the introduction of XML/RDF-serialisation and XSD). We will return to this difference, but for now, let's see what usually happens.

Because http://semantic.nodix.net/movie/Terminator leads to nowhere, and I'm far too lazy to make a website for the Terminator just for this example, we will take another URI for the movie. Jumping to IMdb we quickly find the appropriate one, and then we can reformulate our statement:

http://www.imdb.com/title/tt0088247/ http://purl.org/dc/elements/1.1/creator "James Cameron".

Great! Our subject is a valid URI, clicking on http://www.imdb.com/title/tt0088247/ (or pasting it to a browser) will tell you more about the subject, and we have a valid RDF statement. Everything is fine again...

...until next time, where we will discuss the minor problems of our solution.

Pah!

Geht nicht auf diese Seite. Schaut euch auf gar keinen Film das grausige Foto von mir an. Das eigentlich Foto, dass ich dann auch für meine neue Webseite verwendet habe sieht nämlich viel besser aus. Ignoriert also diese Seite. Kapiert?

Habe es hingegen tatsächlich endlich geschafft, hinter den Link über Denny, der schon seit Anfangszeiten von Nodix vorhanden ist, auch mal Inhalt zu bringen. Die Seite verweist jetzt auf die äußerst schreibfreundliche Seite denny.vrandecic.de. Letztlich soll sich hier auch irgendwann CV, Publikationsliste und ähnliches tummeln, eben das, was man als eigentlich Homepage im klassischen Sinn versteht. So, jetzt aber endgültig, auf Richtung Neandertal...

What's in a name - Part 1

There are tons of mistakes that may occur when writing down RDF statements. I will post a six part series of blog entries, starting with this one, about what can go wrong in the course of naming resources, why it is wrong, and why you should care - if at all. I'll try to mix experience with pragmatics, usability with philosophy. And I surely hope that, if you disagree, you'll do so in the comments or in your own blog.

The first one is the easiest to spot. Here we go:

"Politeia" dc:creator "Plato".

If you don't know about the differences between Literals, QNames and URIs, please take a look at the RDF Primer. It's easy to read and absolutely essential. If you know about the differences, you already know that the above said actually isn't a valid RDF statement: you can't have a literal as the subject of a statement. So, let's change this:

philo:Politeia dc:creator "Plato".

What's the difference between these two? In the first one you say that "Plato" is the creator of "Politeia" (we take the semantics of dc:creator for granted for now). But in the second you say that "Plato" is the creator of philo:Politeia. That's like in Dragonheart, where Bowen tries to find a name for the dragon because he can't just call him "dragon", and he decides on "draco". The dragon comments: "So, instead of calling me dragon in your own language, you decide to call me dragon in another language."

Yep, we decide to talk about Politeia in another language. Because RDF is another language. It tries to look like ours, it even has subjects, objects, predicates, but it is not the language of humans. It is (mostly) much easier, so easy in fact even computers can cope with it (and that's about the whole point of the Semantic Web in the first place, so you shouldn't be too surprised here).

"Politeia" has a well defined meaning: it is a literal (the quotation marks tell you that) and thus it is interpreted as a value. "Politeia" actually is just a word, a symbol, a sign pointing to the meant string Politeia (a better example would be: "42" means the number 42. "101010b", "Fourty-Two" or "2Ah" would have been perfectly valid other signs denoting the number 42).

And what about philo:Politeia? How is it different from "Politeia", what does this point to?

philo:Politeia is a Qualified Name (QName), and thus ultimatively a short-hand notation for an URI, an Unified Resource Identifier. In RDF, everything has to be a resource (well, remember, RDF stands for Resource Description Framework), but that's not really a constraint, as you may simply consider everything a resource. Even you and me. And URIs are names for resources. Universally (well, at least globally) unique names. Like philo:Politeia.

You may wonder about what your URI is, the one URI denoting you. Or what the URI of Plato is, or of the Politeia? How to choose good URIs, and what may go wrong? And what do URIs actually denote, and how? We'll discuss this all in the next five parts of this series, don't worry, just stay tuned.

Team America

Ab morgen bin ich im Neandertal, und wer weiß schon, wie da die Internetverbindung ist. Also muss ich noch schnell einen Tipp für alle Kinogänger loswerden, zu einem Film, den niemand verpassen sollte - Team America!

Ein Film mit Alec Baldwin, Liv Tyler, Matt Damon, Sean Penn, Michael Moore, Samuel L. Jackson, Kim Il-Yong, George Clooney und vielen anderen - und das waren nur Nebenrollen! Das South Park Team macht einen bösen, bösen Film, mit schwärzesten Humor und einem Hauch an Kritik an gewissen amerikanischen imperialistischen Tendenzen.

Heißer Sex, unglaubliche Action-Sequenzen, wie sie noch nie zuvor mit dieser Technik (Marionetten) ausgeführt wurden, an den großen Schauplätzen dieser Welt (Nordkorea, Kairo, Paris, Mount Rushmore, Washington) - was will man mehr? Für ausgesprochene Cineasten sind zudem äußerst subtile Zitate auf die großen Kinofilme der letzten Jahrzehnte eingebaut (Star Wars oder Matrix).

Im Kino ab dem 30. Dezember.

Auch auf baumgarf wird ein Review von Team America geboten. Wer lieber etwas anderes ansehen möchte, sollte es mit Ocean's Twelve versuchen - der coolste Film des Winters! Wer auf seichteren Humor steht, kann es auch getrost mit Trouble ohne Paddel versuchen (auch auf Baumgarf findet sich ein Review, jedoch wählt Ralf den Originaltitel Survival Camp, weil er den "deutschen" Titel nicht mag. Sich aber über den schleichenden Verfall des Deutschen beschweren, tsts. Heuchler ;)

Why we will win

People keep saying that the Semantic Web is just a hype. That we are just an unholy chimaera of undead AI researchers talking about problems solved by the database guys 15 years ago. And that our work will never make any impact in the so called real world out there.

As I stated before: I'm a believer. I'm even a catholic, so this means I'm pretty good at ignoring hard facts about reality in order to stick to my beliefs, but it is different in this case: I slowly start to comprehend why Semantic Web technology will prevail and make life better for everyone out there. It' simply the next step in the IT RevoEvolution.

Let's remember the history of computing. Shortly after the invention of the abacus the obvious next step, the computer mainframe, appeared. Whoever wanted to work with it, had to learn to use this one mainframe model (well, the very first ones were one-of-a-kind machines). Being able to use one didn't necessarily help you using the other.

First the costs for software development were negligible. But slowly this changed, and Fred Brooks wrote down his experience with creating the legendary System/360 in the Mythical Man-Month (a must-read for software engineers), showing how much has changed.

Change was about to come, and it did come twofold. Dennis Ritchie is to blame for both of them: together with Ken Thompson he made Unix, but in order to make that, he had to make a programming language to write Unix in, this was C, which he made together with Brian Kernighan (this account is overly simplified, look at the history of Unix for a better overview).

Things became much easier now. You could port programs in a simpler way than before, just recompile (and introduce a few hundred #IFDEFs). Still, the masses used the Commodore 64, the Amiga, the Atari ST. Buying a compatible model was more important than looking at the stats. It was the achievement of the hardware development for the PC and of Microsoft to unify the operating systems for home computers.

Then came the dawning of the age of World Wide Web. Suddenly the operating system became uninteresting, the browser you use was more important. Browser wars raged. And in parallel, Java emerged. Compile once, run everywhere. How cool was that? And after the browser wars ended, the W3Cs cries for standards became heard.

That's the world as it is now. Working at the AIFB, I see how no one cares what operating system the other has, be it Linux, Mac or Windows, as long as you have a running Java Virtual Machine, a Python interpreter, a Browser, a C++ compiler. Portability really isn't the problem anymore (like everything in this text, this is oversimplified).

But do you think, being OS independent is enough? Are you content with having your programs run everywhere? If so, fine. But you shouldn't be. You should ask for more. You also want to be independent of applications! Take back your data. Data wants to be free, not locked inside an application. After you have written your text in Word, you want to be able to work with it in your Latex typesetter. After getting contact information via a Bluetooth connection to your mobile phone, you want to be able to send an eMail to the contact from your web mail account.

There are two ways to achieve this: the one is with standard data formats. If everyone uses vCard-files for contact information, the data should flow freely, shouldn't it? OpenOffice can read Word files, so there we see interoperability of data, don't we?

Yes, we do. And if it works, fine. But more often than not it doesn't. You need to export and import data explicitly. Tedious, boring, error prone, unnerving. Standards don't happen that easily. Often enough interoperability is achieved with reverse engineering. That's not the way to go.

Using a common data model with well defined semantics and solving tons of interoperability questions (Charset, syntax, file transfer) and being able to declare semantic mappings with ontologies - just try to imagine that! Applications being aware of each other, speaking a common language - but without standard bodies discussing it for years, defining it statically, unmoving.

There is a common theme in the IT history towards more freedom. I don't mean free like in free speech, I mean free like in free will.

That's why we will win.

Dick werden...

Was las mir Schwesterchen schönes vor? (ohne jedoch eine Quelle anzugeben)

"Dick wird man nicht von dem, was man Heiligabend bis Neujahr isst, sondern von dem, was man Neujahr bis Heiligabend isst"

Wahr gesprochen!

Love is...

"Love is what's in the room with you at Christmas if you stop opening presents and listen."

Angeblich aus einer Studie, in der 4- bis 8-jährige Kinder gefragt wurden, was Liebe ist. Herzallerliebst.

Leider konnte ich die Originalstudie nicht finden - vielleicht schafft es jemand anderes ja - aber der Text wird ständig im Netz zitiert: hier, hier hier, hier oder hier, aber auch hier. Google findet über 60.000 Treffer... wahrscheinlich, dass der Text erfunden ist.

Trotzdem schön, ihn zu lesen.

Amazonempfehlung

Ich bin von Amazons Empfehlungen wirklich begeistert. Mal ehrlich - welcher Buchhändler kennt heute noch seine Kunden so gut, dass er so treffende Vorschläge machen kann?

Nur heute war ich etwas verdutzt, weil mir Leicht Verdientes Gold empfohlen wurde. Stimmt, eine wirklich hervorragende Anschaffung. Schließlich habe ich ja mitgeschrieben...

Vier fehlende Posts

Wahrscheinlich hat es ohnehin kein Mensch bemerkt, aber bei der Umstellung auf blogger.com bemerkte ich den Verlust von vier Posts: vom 5. November 2002, vom 5. und 18. Dezember 2002 und vom 23. Januar 2003.

Habe sie wiedergefunden und eingestellt (Sicherheitskopien sind was feines). Dies ist übrigens Post Nummer 175 oder so, es scheint hier keine automatische Methode zu geben, das automatisch nachzuzählen. Gar nicht mal so viele, für knapp vier Jahre - Schwesterchen hat im Schönsten Blog von Welt in einem Monat fast 40 Einträge geschafft! Und des Wahnsinns fette Beute brauchte für etwa 140 Einträge auch weniger als drei Jahre.

Kurz, ich bin ein unregelmäßiger, fauler Blogger. Trotzdem danke für die vielen Besuche! (Zu den Besucherzahlen, der Ehrlichheit halber, unter uns: nakit-arts hat inzwischen mehr regelmäßige Besucher als der Nodix-Blog. Gratuliere Dir, Schwesterchen!)

Wissenswertes über Jamba

Herzallerliebst geschrieben, dazu noch äußerst unterhaltsam, und dennoch aufklärerischer und kritischer Inhalt:

http://spreeblick.de/wp/index.php?p=324

Da freut man sich. Was las ich vor kurzem in einem Telepolis-Interview mit Norbert Bolz gelesen?
"Ich lese am liebsten das ›Streiflicht‹ in der Süddeutschen Zeitung und ›Das Letzte‹ in der Zeit, also Glossen. Diese Glossen haben sehr viel mehr Sprengkraft als die Kommentare von irgendeinem Leitartikler. Solche Texte sind so voraussehbar in ihrer politischen Korrektheit, dass sie mich einfach nur anöden. Über die Form des Witzes lassen sich so manche politischen Informationen und Kritik viel besser vermitteln."

Na, dann ist der obige Link ein Beispiel für die Information der Zukunft.

I am weak

Basically I was working today, instead of doing some stuff I should have finished a week ago for some private activities.

The challenge I posed myself: how semantic can I already get? What tools can I already use? Firefox has some pretty neat extensions, like FOAFer, or the del.icio.us plugin. I'll see if I can work with them, if there's a real payoff. The coolest, somehow semantic plugin I installed is the SearchStatus. It shows me the PageRank and the Alexa rating of the visited site. I think that's really great. It gives me just the first glimpse of what metadata can do in helping being an informed user. The Link Toolbar should be absolutely necessary, but pitily it isn't, as not enough people make us of HTMLs link element the way it is supposed to be used.

Totally unsemantic is the mouse gestures plugin. Nevertheless, I loved those with Opera, and I'm happy to have them back.

Still, there are such neat things like a RDF editor and query engine. Installed it and now I want to see how to work with it... but actually I should go upstairs, clean my room, organise my bills and insurance and doing all this real life stuff...

What's the short message? Get Firefox today and discover its extensions!

Nachholtag

Herrje, fast zwei Wochen nichts gepostet. Immerhin, man kriegt anfragen: ist was? Wieso liest man nichts? Allerlei :)

Zunächst: alles prima, danke der Nachfragen. Außer, dass die DSA4 Website nicht tut, und Andre nicht zu erreichen ist, und ich wahrscheinlich wieder umziehen muss mit der Seite. Ich glaube, jetzt hole ich mir einfach einen eigenen Webspace, der auch PHP kann, besser noch Python, und all das für wenig Geld. Aber da ich faul bin, und mit 1&1 eigentlich zufrieden bin, weiß ich nicht, ob ich richtig Lust auf umziehen habe... na, mal sehen.

So, jetzt noch schnell: die letzten Tage habe ich natürlich auch Filme geschaut, aber statt jetzt selber Kritiken zu schreiben, verweise ich auf diejenigen, die den Film mit mir geschaut haben, und dies selbst gebloggt haben, dahinter nur eine ganz kurze Ein-Satz-Wertung von mir:

• Anatomie einer Entführung (Brilliante Schauspieler langweilen den Zuschauer gezielt zu Tode)
• New York Taxi (Lustig, aber nichts, was man nicht verpassen darf; die brasilianischen Bankräuberinnen sehen echt verdammt gut aus)
• Die Unglaublichen (Schwesterchen / baumgarf (Wow! Unglaublich gute Story, da hat jemand bei Frank Miller geklaut - hinreißend komisch auch!)
• The Lord of the Rings: Return of the King Special Extended Edition (bester Film des letzten Jahres noch besser gemacht, endlich, komplett! Schwärm. Verpasst die Easter Eggs nicht: ins Menü, Szenenauswahl, letzte Szene, und dann eins runter - ein kleiner Ring erscheint. Auswählen. Sehr, sehr lustig! Klappt auf beiden Film-DVDs)

Imagine there's a revolution...

... and no one is going to it.

This notion sometimes scares me when I think abou the semantic web. What if all this great ideas are just to complex to be implemented? What if it remains an ivory tower dream? But, on the other hand, how much pragmatism can we take without loosing the vision?

And then, again, I see the semantic web working already: it's del.icio.us, it's flickr, it's julie, and there's so much more to come. The big time of the semantic web is yet to come, and I think none of us can really imagine the impact it is going to have. But it will definitively be interesting!

Perspektive Deutschland

Ich mag diese Umfrage, und mache schon seit Jahren mit: ich kann auch nur empfehlen, selber mal die Meinung reinzudrücken. Schirmherr ist Richard von Weizsäcker, den älteren von uns noch bekannt als vielleicht meistrespektiertester Bundespräsidents des letzten Vierteljahrhunderts. Also, mitmachen! Ich glaube, gewinnen kann man auch etwas...

AcceLogiChip

Accelerated logic chips - that would be neat.

The problem with all this OWL stuff is, that it is computationally expensive. Google beats you in speed easily, having some 60.000 PCs or so, but indexing some 8 billion web pages, each with maybe a thousand words. And if you ever tried Googles Desktop Search, you will see they can perform this miracles right on your PC too! (Never mind that there are a dozen tools doing exactly the same stuff Googles Desktop Search does, just better - but hey, they lack the name!)

What does the Semantic Web achieve? Well, ever tried to run a logic inferencing engine with a few million instances? With a highly axiomatized TBox of, let's say, just a few thousand terms? No? You really should.

Sure, our PCs do get faster all the time (thanks to Moores Law!), but is that fast enough? We want to see the Semantic Web up and running not in a few more iterations of Moores Law, but much, much earlier. Why not use the same trick graphic magicians did? Highly specialized accelerated logic chips, things that can do your tableu reasoning in just a fraction of the time needed with your bloated all-purpose-CPU.

Wort des Jahres

Merriam-Webster hat das (englischsprachige) Wort des Jahres bekanntgegeben: Blog.

World Wide Prolog

Today I had an idea - maybe this whole Semantic Web idea is nothing else than a big worldwide Prolog program. It's the AI researchers trying to enter the real world through the W3Cs backdoor...

No, really, think about it: almost all most people do with OWL is actually some logic programing. Declaring subsumptions, predicates, conjunctions, testing for entailment, getting answers out of this - but on a world wide scale. And your browser does the inferencing for you (or maybe the server? Depends on your architecture).

They are still a lot of questions open (and the actual semantic differences between Description Logics, and Logic Programming surely ain't the smalles ones of them), like how to infere anything with contradicting data (something that surely will happen in the World Wide Semantic Web), how to treat dynamics (I'm not sure how to do that without reification in RDF), and much more. Looking forward to see this issues resolved...

Das Vermächtnis der Tempelritter

aus der Reihe Filme in 50 Worten

Es gibt keinen Film der besser geeignet ist als dieser, um die Wartezeit auf Indiana Jones 4 zu verkürzen. Ein sehr flotter Film, überraschend intelligenter Plot, annehmbar recherchierter Hintergrund (na ja, ein paar Fehler könnte man natürlich bemäkeln, aber darüber sehe ich hinweg), äußerst witzige Sprüche - er nimmt sich niemals zu ernst, doch vermeidet es auch, albern zu werden, kurz: gute Action, anschauen. Indy hat mindestens so gut zu werden!

Übrigens, meine Mitkinogänger bloggen, wie ich sehe jetzt auch selbst ganz fleißig ihre Meinung zu den angeschauten Filmen - lest Schwesterchens Blogeintrag zum Vermächtnis der Tempelritter und Buddys Blogeintrag zu Alles auf Zucker, von gestern.