(Last Update: September 30th, 2010)
Welcome. This is the personal homepage of Joost Vennekens. Here, you can find some information about me, my research (with links to downloadable publications), and my educational responsabilities. There are also some pictures you can look at, and some links to websites I find interesting.
Information for my students at De Nayer, is here.
After obtaining my PhD in May 2007 and working for two years as a postdoctoral researcher (funded by the FWO) in the Knowledge Representation and Reasoning group at the K.U. Leuven, I am now working at Campus De Nayer of Lessius Mechelen. I am, however, still an affiliated researcher of the Dept. Computer Science of the K.U. Leuven. This university page contains some useful contact information about me. If you want to get in touch with me, I suggest that you do so by email. (In case the link does not work for you, my address is my firstname dot my lastname at cs dot kuleuven dot be.)
My research focuses on two different topics:
Approximation theory (Denecker, Truszczynski and Marek) is an algebraic fixpoint theory, which naturally captures certain families of semantics for knowledge representation languages such as logic programming, default logic, and autoepistemic logic. The algebraic nature of this theory allows general results to be proven in a clean, compact, and elegant manner, without getting bogged down in syntactical details. Moreover, by proving a single theorem in approximation theory, one immediately obtains results for a number of different logics and, typically, also for an entire family of semantics for these logics. As such, the tedious task of reproving essentially the same property in slightly different circumstances can be avoided. We have studied two different knowledge representation properties in approximation theory.
Together with Marc Denecker and building on work by David Gilis, I developed a theory of modularity in approximation theory. We then used this to prove generalize certain known modularity results for Logic Programs, Autoepistemic Logic, and Default Logic. The most complete account of this work can be found in our journal paper [1] on this topic. More recently, we have also used our methodology to prove some modularity results for ID-logic [2].
The second topic is that of predicate introduction, i.e., the common transformation of introducing a new symbol to abbreviate some complex formula. One might do this, for instance, to make a theory more readable and compact by singling out a subformula that appears in a number of different locations, or to transform it into some useful normal form. Once again, we studied this topic at the level of approximation theory and then applied this result to logic programming [6], where it significantly generalizes existing results by also allowing the new symbols to be defined recursively, and to autoepistemic logic [7].
The goal of this work is basically to make it easier to define probability distributions. We try to accomplish this by adding a probabilistic component to logical knowledge representation languages. This research has lead to the development of CP-logic, which allows a probability distribution to be represented as a set of conditional probabilistic events and has a strong focus on causality. The best place to read about CP-logic is [3]. CP-logic originate as an attempt to clarify the intuitions behind the probabilistic logic programming language of Logic Programs with Annotated Disjunctions (LPADs), which was introduced in [4]. Technical results and proofs about the relationship between LPADs and various related formalisms can be found in the technical report [5].
This is a selection of my publications. A complete and up-to-date list can be found here.
| [1] | Joost Vennekens, David Gilis and Marc Denecker. Splitting an operator: Algrebraic modularity results for logics with fixpoint semantics. ACM Transactions on Computational Logic 7(4), pp. 765--797, October, 2006. [ps, pdf] |
| [2] | Joost Vennekens, and Marc Denecker. An algebraic account of modularity in ID-logic. Logic Programming and Nonmonotonic Reasoning, LPNMR 2005, Proceedings, vol 3662, Lecture Notes in Computer Science, pp. 291-303, 2005. [ps,pdf] |
| [3] | Joost Vennekens, Marc Denecker, and Maurice Bruynooge. CP-logic: A language of causal probabilistic events and its relation to logic programming. Draft. [ps, pdf] |
| [4] | Joost Vennekens, Sofie Verbaeten and Maurice Bruynooghe. Logic Programs with Annotated Disjunctions. Proceedings of the 20th International Conference on Logic Programming (ICLP), 2004. [ps, pdf] |
| [5] | Joost Vennekens and Sofie Verbaeten. Logic Programs with Annotated Disjunctions. Department of Computer Science, K.U.Leuven, Technical Report CW 368, 2003. [ps, pdf] |
| [6] | Joost Vennekens, Maarten Mariën, Johan Wittocx, and Marc Denecker. Predicate introduction for logics with a fixpoint semantics. Part I: Logic programming. Fundamenta Informaticae 79(1-2), pp. 187---208, September, 2007. [ps, pdf] |
| [7] | Joost Vennekens, Maarten Mariën, Johan Wittocx, and Marc Denecker. Predicate introduction for logics with a fixpoint semantics. Part II: Autoepistemic logic. Fundamenta Informaticae 79(1-2), pp. 209---227, September, 2007. [ps, pdf] |
| [8] | Joost Vennekens. Algebraic and logical study of constructive processes in knowledge representation. PhD thesis. KU. Leuven, May 2007. [pdf] |
If you're interested in wasting some time and having fun at the same time, I can heartily recommend this lovely collection of math-related funnies:
Some useful links about probabilistic logic programming: Some of the people I work with also have webpages, such as: I also read a few webcomics: All of these are cool, fun, groovy and/or worthy of your attention.Two of my friends like to photograph stuff. Kris has some of his pictures displayed here. Bert's stuff can be seen here. Go and have a look; you won't be disappointed!
By the way, if you like looking a pretty pictures, Philip Greenspun's site has a lot of pictures from his various travels. Incidentally, Mr. Greenspun is also known for his tenth law. Which neatly brings us to the topic of LISP, thus providing me with a nice opportunity to point out the fantastic collection of essays (some LISP-related, some not) on Paul Graham's website.
Finally, if you feel like making this world a better place, here are some worthy causes to support: Usually, you can find a lot more good causes on R.M. Stallman's homepage.This webpage is maintained by Joost Vennekens. It was written in GNU Emacs, the world's finest desktop environment. If my HTML upsets you or your favorite browser, please let me know. This page is not an official K.U.Leuven page; all views expressed here are my own. Read the official disclaimer here .