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October 31, 2008

ISWC2008, Karlsruhe

ISWC2008 has just finished (I am still at the hotel, leaving for home in a few hours). As usual, it is very difficult to give an exhaustive overview of the whole conference, not only because there were way too many parallel things going on, but everyone’s interests are different… These are just a few impressions. Still have to find time reading through some of the papers in more details.

Great keynote by John Giannanderea from Metaweb, ie, freebase. Freebase has always been an exciting project but the great news from the Semantic Web community’s point of view is that freebase has opened its database to the rest of the World in RDF, too. As such, freebase will soon become part of the Linking Open Data cloud (I guess there are still some details to be ironed out, and I saw John and Chris Bizer starting to discuss these). Actually, it was also interesting to hear again and again from John that the internal structure of freebase is based on a directed, labeled graph model, because that was the only viable option for them to build up what they needed. Sounds familiar?

An interesting point of the keynote was when John was wondering whether Metaweb is therefore a Semantic Web company or not. He thought that yes, it is, because the internal structure is compatible with RDF, it relies on identifiers with URIs, and is Web based. But he also thought that, well, it is not because… no description logic is in use, nor ontologies. Sigh… This still reflects the erronous view that one must use description logic to be on the Semantic Web. Wrong! So I went up to the mike and welcomed Metaweb in the growing club of Semantic Web companies…

Among the many papers I was interested in, let me refer to the one of Eyal Oren et al., “Anytime Query Answering in RDF through evolutionary algorithms” and, actually, a related submission from the same research group to the Billion Triple Challenge, called MaRVIN. In both cases the issue is that while handling very large datasets one might not necessarily want or is interested in _all_ solutions to a given query (or inferences, in case of MaRVIN) but, rather, whatever can be reached within a reasonable time. Ie, essentially, trading completeness for responsiveness. Whether genetic algorithms are the answer, as explored by Eyal and friends, or some other techniques, nobody knows; as Eyal clearly acknowledged, these are first attempts and we have to wait a few more years and furter results to get a feeling where it will lead. But the direction is really interesting.

This actually leads to what was, for me, the highlight of the conference, namely the SW Challenge, both the traditional Open Call as well as the new Billion Triple Challenge (there more details on both on the challenge’s web site). The entries were really impressive. As Peter Mika said in his closing comments on the challenge, long gone are the days when a challenge was some techie keyboard manipulation; the entries all had great user interface design, with the real regards to non-expert end users who may or may not know (and probably do not care) that the underlying technology is Semantic Web.

Among the finalists in the open call Chris Bizer presented DBPedia Mobile, (see also their site) ie, a system to access the full power of DBPedia (and, actually, the LOD cloud in general) from an iPhone via a proxy somewhere on the Web. The proxy is actually a hugely powerful environment, making use of Falcon and Sindice, and a bunch of query engines distributed over the network, all peeking into the LOD cloud and, actually, adding items to it, eg, photos taken on the iPhone. A few years ago all this would have had a SciFi edge to it, and now it was running at the conference…

Eero Hyvönen showed their HealthFinland portal (see also their site), soon to be deployed by the Finnish health authorities. Half of the system is, shall we say, more “traditional” (hm, well, what this means is that it would have been revolutionary two years ago:-), a number of serious ontologies governing health related data integration and search into the data. However, what I found exciting is the other half. Indeed, Eero and friends realized that search facets derived from serious ontologies are not really ideal for everyday end users. Therefore, they made a survey among users, derived a number of terms to be used on the user interface level, and bound these terms internally to the ontology. The result is a much more friendly system that still has the power offered by ontology directed search.

Actually, having Eero’s and Chris’ system presented side by side was also interesting from another point of view, namely to show that there are cases when using serious ontologies is important and there are cases when it isn’t. When I use an iPhone to navigate in a city and get information about, say, historical buildings then a bit of scruffiness is really not a problem. Speed, interaction, richness of data is more important. However, when it comes to, e.g., health issues, I must admit that I am prepared to wait a bit if I am sure that the results go through the rigorous inference and checking processes that one can achieve through the usage of formal ontologies. This is not the place when one should tolerate scruffiness. The stack (or, to quote Eric Miller, the “menu”) of Semantic Web technologies is rich enough to allow for both; choose what you need! All those discussions description logic vs. Semantic Web in general is futile in my view…

And then came benji’s paggr system (which actually won the Challenge in the Open Call track). Are you user of netvibes, iGoogle, or the new Yahoo user interface? Then you know what it means to quickly build up a Web page using small widgets accessing RSS feeds, stock quotes, clocks, etc. Now imagine that each of these widgets is in fact a small sparql query with some wrapper to present the result properly. Package that into a nice user interface that benji has always been a master of, and you get paggr. Not yet public, but I already signed up to play with it as soon as it is… This will really be cool!

As for the Billion Triples challenge: I already referred to MaRVIN, but there were a bunch of others like SearchWebDB or SemaPlorer, or SAOR. In some cases massively parallel storage approaches, not only offering near real time (federated) SPARQL query possibilities, but, in some cases, preprocessing it with a lower level RDFS or OWL fragment inferencing. All that done starting with millions of triples integrating all kinds of public datasets, yielding storages going beyond the 1 Billion triple mark. And let us not forget that this mark had already been reached by companies such as Tallis or OpenLink, so these new architectures just add to the lot… These were also particularly interesting with and eye to the new OWL RL profile that is being defined in the W3C OWL Working group and which aims at exactly such setups.

Let me finish with another remarkable entry, although this one did not win a price. i-MoCo created a small navigation system over a triple store containing “only” 250 million triples. So what is the big deal, you might say? Well, all the triples were stored on… an iPhone! So the next challenge will probably be to get, say, 10 billions of triples or more on your phone. Just wait a few years…



  1. Thanks! 🙂

    Comment by Benjamin Nowack — October 31, 2008 @ 17:40

  2. […] Sattler from The University of Manchester for winning the keenly fought best paper prize at the International Semantic Web Conference (ISWC 2008) in Karlsruhe for their paper “Laconic and Precise Justifications in OWL”. An abstract […]

    Pingback by Congratulations Matthew Horridge! « O’Really? at Duncan.Hull.name — October 31, 2008 @ 19:47

  3. […] Herman has a review of ISCW2008. Posted by Brian Manley Filed in LinkedData, SemanticWeb, […]

    Pingback by triple|scape » Blog Archive » TWILD for November 1, 2008 — November 2, 2008 @ 0:56

  4. […] A very good write-up of the general spirit and the highlights by Ivan Herman (W3C): https://ivanherman.wordpress.com/2008/10/31/iswc2008-karlsruhe/ […]

    Pingback by LarKC weblog » Blog Archive » Write-up on ISWC 2008 — November 7, 2008 @ 18:51

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