Birte Glimm

Birte Glimm

Research Assistant

+44 1865 283529

Wolfson Building, Parks Road, Oxford OX1 3QD

Interests

My main research interests are knowledge representation and reasoning. In particular, I enjoy developing and implementing algorithms for reasoning in expressive description logics. Most recently, I implemented a datatype checker for the HermiT reasoner that allows for reasoning over concrete domains such as Strings, Integers, etc. I have also developed algorithms for conjunctive queries in the Description Logics SHIQ and SHOQ together with Ian Horrocks, Uli Sattler, and Carsten Lutz. SHIQ is the Description Logic that underlies OWL Lite, which is one of the W3C standardised Web Ontology Languages. Conjunctive queries are well known in the database community, which motivated the decision to study whether conjunctive query entailment is also decidable for expressive Description Logic knowledge bases. I also analysed the complexity of the developed algorithms and proved 2ExpTime upper bounds. For SHIQ, Carsten Lutz showed that the bound is tight and that conjunctive queries for SHIQ are, therefore, strictly harder than the standard reasoning tasks, such as knowledge base consistency or instance retrieval, which are ExpTime-complete. Recently, I have worked with Yevgeny Kazakov on the complexity of expressive Description Logics with role conjunctions, which is a problem closely related to query answering. Our work shows, among other things, that conjunctive queries for SHOIQ, which underlies the OWL DL standard, are at least N2ExpTime-hard. Decidability of this problem is, however, still open and part of my future work.

Biography

Currently, I work as a research assistant in the Computing Laboratory of the University of Oxford. I work in the Information Systems group, mainly on developing algorithms for automated reasoning in expressive Description Logics and on the implementation of the HermiT reasoner. You can contact me at firstname.lastname at comlab.ox.ac.uk.

From September 2004 until September 2007 I was a PhD student in the Information Management Group at the University of Manchester and I was honoured with the Best Thesis Award from the School of Computer Science at Manchester University in 2008. The topic of my PhD thesis is Querying Description Logic Knowledge Bases and I was jointly supervised by Prof. Ian Horrocks and Prof. Ulrike Sattler. From September 2001 until July 2004 I studied Computer Science in the Hamburg University of Applied Sciences and I received my bachelor degree with an award for the best degree. The topic of my bachelor report was "A Query Language for Web Ontologies" and I wrote the report as a visiting student at the University of Manchester.

Before studying Computer Science, I worked for 3.5 years in Industry and did another degree in Communication Design. My full CV in PDF format is available here.

Selected Publications

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Optimized DL Reasoning via Core Blocking

Birte Glimm, Ian Horrocks and Boris Motik

2010.

Details | BibTeX | Download (pdf)

Status QIO: Conjunctive Query Entailment is Decidable

Birte Glimm and Sebastian Rudolph

In Proceedings of the 12th International Conference on the Principles of Knowledge Representation and Reasoning (KR-10). 2010.

To Appear

Details | BibTeX

Conjunctive Query Entailment: Decidable in Spite of O, I, and Q