It’s the end of a interesting and enjoyable ESWC’11 conference in Heraklion, Crete. Compared to other conferences, there were many keynote speeches (and not all of them that much on the Semantic Web, but interesting nevertheless), and, as usual, there were parallel sessions with (unfortunately) many co-scheduled presentations I would have liked to attend. Here follows a few notes on them (which I might update once travelled back to SA, as this is written rather hastily before departure).
Jim Hendler’s talk was entitled “Why the Semantic Web will never work”—with the quotation marks. There have been quite a few people uttering that sentence, but, in Hendler’s review of the past 10 years, we actually have achieved more in some areas than initially anticipated and more than pessimists thought was feasible. For instance, “the semantic web will never scale”: it does, according to Hendler, as demonstrated, e.g., by participants in the billion triple challenge and the growing LOD data cloud. Or the “folksonomies will win” (as opposed to, at least, structured vocabularies): wrong again, mainly because it does not achieve its goal without “social context” and it lacks the crucial aspect of links between entities. However, these achievements are principally in the bottom part of the Semantic Web layer cake and Hendler claims that the “ontology story is still confused”, although OWL is to a large degree “succeeding as a KR standard”. Key challenges for Hendler include: relating linked data to ontologies, the equivalent of a database calculus for linked data, and the need for providing a means for evaluating reasoning with incomplete and possibly inconsistent data. UPDATE (13-6): Hendler’s slides are on slideshare.
Lars Backstrom, data scientist at Facebook, gave a keynote about analyzing FB data and working toward ranking and filtering news feeds by turning it into a classification problem using a set of properties (localization, relation to actor, and others). Interestingly, Backstrom emphasized that FB is moving toward more structured data, which makes it easier to manage and analyse with the algorithms they are developing. If that is a good thing or not is a separate discussion, especially regarding privacy issues, which was the talk of Abe Hsuan about (clearly, this does not hold only for FB but the web in general). According to Hsuan, “Privacy cannot exist on a lawless Semantic Web”. It was good for several after-talk discussions among the attendees, and the last word on how to deal with all this has not been said and done yet. In this context, someone may want to have a look at episode 3 of The virtual revolution documentary about non-free services on the Web, the TED-talk on The filter bubble, or the less recent Database nation book.
Andraz Tori, CTO of Zemanta, gave a keynote describing some background of the ‘writing help’, as offered by WordPress since recently, whilst trying to avoid wrong usage of it and cleaning up the data. As you may have guessed, I have not used that feature yet when writing my blog posts (and do not see the need for it from my perspective). Prasad Kantamneni from Yahoo! Gave an interactive keynote on HCI applied to the effects of different web interfaces for their search engines—and the consequences on revenue, which was lively and interesting. Seemingly ‘silly little things’ like putting the keyword in boldface in the search results makes a big difference on how a user scans through the results (more efficient), likewise auto-completion that in the end make you read more of the results page.
Last, but most certainly not least, Chris Welty gave the conference dinner keynote, which was entertaining. He described some hurdles they had overcome in building ‘Watson’, a sophisticated question answering engine that finds answers to trivia/general knowledge quizzes for the Jeopardy! game that, in the end, did consistently outperform the national human experts on it. The talk was filled with entertaining mistakes they encountered during the development of Watson, and what it required to fix them. The key message was that one cannot go in a linear fashion from natural language to knowledge management, but one has to use a integration of various technologies to make a successful ‘intelligent’ tool.
Sessions and other things
Normally I have a dense section on the papers presented in the session here, but due to the very busy conference schedule and shortage of free online papers before the conference, I did not get around reading all the papers that I would have liked (and I don’t cite papers I have not read, still roughly following my approach to conference blogging). The one on removing redundancy in ontologies presented by Jens Wissmann  was quite interesting, in particular for its creative reuse of computing justifications to remove ‘redundant’ axioms, i.e., those which can be derived from other knowledge represented in the ontology anyway. This was computationally costly, so they also developed another algorithm with better performance; details and experimental results can be found in the paper. My own paper  on the experiment of the use of foundational ontologies in ontology engineering was well-received, and generated quite some interest, such as on the quality of the foundational ontologies themselves and how the results presented could translate to their particular domain ontology scenario. I may add something on epistemic queries, computing generalizations, matching 4K ontologies in one year, and cross-lingual ontology mappings (provided I find the time to do so in the upcoming days).
The panel session about e- and open- Government was a bit meager and can be summarized as: Linked Open Data (LOD) is good and catching on well but the integration problems still exist, and we need (at least) structured controlled vocabularies to fix it.
 Stephan Grimm and Jens Wissmann. Elimination of redundancy in ontologies. In: Proceedings of the 8th Extended Semantic Web Conference (ESWC’11). Heraklion, Crete, Greece, 29 May – 2 June 2011. Springer LNCS 6643, 260-274.
 Keet, C.M. The use of foundational ontologies in ontology development: an empirical assessment. In: Proceedings of the 8th Extended Semantic Web Conference (ESWC’11). Heraklion, Crete, Greece, 29 May – 2 June 2011. Springer LNCS 6643, 321-335.