PF/Tijah documentation available as technical report

by Djoerd Hiemstra, Henning Rode, and Jan Flokstra

PF/Tijah (Pathfinder/Tijah, pronounce as “Pee Ef Teeja“) is a flexible open source text search system developed at the University of Twente in cooperation with CWI Amsterdam and TU München. The system is integrated in the Pathfinder XQuery database system and can be downloaded as part of MonetDB/XQuery. This report contains user documentation of PF/Tijah, including example usage in three show cases.

For more information, see: PF/Tijah site

Dutch-Belgian IR workshop in Maastricht

The Dutch-Belgian Information Retrieval workshop (DIR) will take place in Maastricht on April 14-15, 2008. The primary aim of the DIR workshop is to provide an international meeting place where researchers from the domain of information retrieval and related disciplines, can exchange information and present innovative research developments. Hinrich Schuetze of the University of Stuttgart will give an invited talk at DIR2008 about his new book “Introduction to Information Retrieval” which will appear in 2008.

Deadline call for papers: 2 February 2008

Entity Ranking on Graphs: Studies on Expert Finding

by Henning Rode, Pavel Serdyukov, Djoerd Hiemstra, and Hugo Zaragoza

Todays web search engines try to offer services for finding various information in addition to simple web pages, like showing locations or answering simple fact queries. Understanding the association of named entities and documents is one of the key steps towards such semantic search tasks. This paper addresses the ranking of entities and models it in a graph-based relevance propagation framework. In particular we study the problem of expert finding as an example of an entity ranking task. Entity containment graphs are introduced that represent the relationship between text fragments on the one hand and their contained entities on the other hand. The paper shows how these graphs can be used to propagate relevance information from the pre-ranked text fragments to their entities. We use this propagation framework to model existing approaches to expert finding based on the entity's indegree and extend them by recursive relevance propagation based on a probabilistic random walk over the entity containment graphs. Experiments on the TREC expert search task compare the retrieval performance of the different graph and propagation models.

[download pdf]

Help Joost de Wit met zijn afstudeeropdracht

Doe mee en maak kans op een gepersonaliseerde DVD Box!

DVD Box Naarmate er meer en meer films, boeken, foto's, nieuwsartikelen en andere content op het web verschijnen wordt het steeds lastiger om onderscheid te maken tussen interessante en niet interessante items. Aanbevelings systemen zijn programma's die proberen te helpen bij het ontdekken van items die voor jou de moeite waard zijn. Een bekend voorbeeld hiervan is de “Customers Who Viewed This Item Also Viewed” functie van Amazon.

Joost de Wit voert een gebruikersonderzoek uit bij TNO ICT om te ontdekken welke aspecten bijdragen aan de kwaliteit van aanbevelingen van TV programma's. Voor het onderzoek is het belangrijk dat er genoeg feedback verzameld wordt. Hoe meer feedback hoe beter. Om deelname te stimuleren heeft TNO ICT een gepersonaliseerde DVD box beschikbaar gesteld. Deze box zal bestaan uit de 5 DVD's die het aanbevelingssysteem als meest interessant voor jou aanmerkt. Waardeer je programma's waar veel actie in voorkomt hoog? Dan zou het maar zo kunnen dat er een actiefilm in je DVD box komt. Het is dus belangrijk dat je veel en goede feedback geeft.

Om mee te doen aan het onderzoek klik je hier.

Composable Markov Building Blocks at DBDBD


Yesterday, Sander Evers presented his composable Markov building blocks at the Dutch Belgian Database Day (DBDBD) in Eindhoven.

The DBDBD is a yearly one-day workshop organized in a Belgian or Dutch university, whose general topic is database research. DBDBD had presentations on a broad range of database and database-related topics, including but not limited to data storage and management, theoretical database issues, database performance, data mining, information retrieval, data semantics, querying, ontologies etc.

Read more on the DBDBD site

Robert Zwerus graduates on storing “PIM” data

Storing Personal Information Management (PIM) data is not trivial, because of the variety in content types. Existing PIM storage systems have shortcomings in performance, data concistency and/or concurrency. In this thesis, we propose several optimisations and test them in Akonadi, KDE’s new central PIM data access manager. The optimisations include using the D-Bus protocol for transmitting short commands and notifications and an IMAP-compatible protocol for data access and modification. The PIM data is kept in its native format, but compressed and split up into separate, frequently-used parts for increased performance. Both the synthetic and use case based evaluation results show that the proposed modifications perform well and help maintain data consistency in Akonadi.

Read more on E-prints

DB colloquium: Volker Krause of


KDE, The K Desktop Environment: Conquer your desktop

Who: Volker Krause of
When: Wednesday, 28 November 2007, 14.30 h. – 15.15 h.
Where: ZI-4126

Volker Krause of will give an overview of what's new in KDE4. He will talk about Akonadi, the Personal Information Management (PIM) Storage Service of KDE. Furthermore, Volker will talk about the currently ongoing cooperations between various universities and KDE (students working on KDE in practical courses, thesis on KDE topics, EU-funded research projects).