Networks and Optimization group news

VIDI grant for Frank Vallentin

Frank Vallentin has been awarded an NWO VIDI grant at the end of 2009 for his research project 'Semidefinite programming and harmonic analysis: Foundations and applications'.

Improved lower bounds for chromatic number

Researcher Fernando de Oliveira Filho of the Centrum Wiskunde & Informatica (CWI) in Amsterdam improved the lower bounds on the chromatic number. He received his PhD degree on December 1 for his thesis 'New Bounds for Geometric Packing and Coloring via Harmonic Analysis and Optimization'.

D. Wojtczak receives Best paper award at ICALP 2009

Following the decision of the programme committee of ICALP 2009 Track B, Dominik Wojtczak (a former PhD student at University of Edinburgh, currently a postdoc at CWI) together with Michael Ummels (PhD student at RWTH Aachen) has won the Best Student ICALP Paper award of Track B for their paper titled: "The Complexity of Nash Equilibria in Simple Stochastic Multiplayer Games".

Mathematics makes wireless networks more efficient

How many cellphone masts should be placed in order to reach everyone? If there are ten additional stations eligible for grants, where can these be placed best? PhD student Erik Jan van Leeuwen of the Centrum Wiskunde & Informatica(CWI) in Amsterdam described the problems with geometric models.

Innovative CWI research wins Free Competition

Two CWI research proposals have received money in the Free Competition 2008 of the Netherlands Organisation for Scientific Research (NWO) division for Exact Sciences. From 58 entries the research of Bert Gerards into matrices and Marie-Collette van Lieshout’s research into Markov polygonal fields were selected among 13 proposals. Three million euros will be divided between them. In total five mathematics proposals were awarded.

Krzysztof R. Apt appointed CWI Fellow

We are happy to announce that Krzysztof R. Apt is appointed CWI Fellow on 1 April 2008. This title is given to outstanding members of CWI's research staff and offers them full freedom in research. Krzysztof Apt has an excellent service record. At CWI Apt is member of the research group Algorithms, Combinatorics and Optimization. He is also Professor at the Institute of Logic, Language and Computation at the University of Amsterdam. In 2006 he was appointed member of the Academia Europæa. He is founder and past Editor-in-Chief of the ACM Transactions in Computational Logic.

New Dutch train timetable made more robust with help of CWI

The 2007 Dutch train timetable, which started on 10 December 2006, has been made more robust with help of CWI researcher Lex Schrijver and programmer Adri Steenbeek. This was pointed out by Leo Kroon from Erasmus University and NS Reizigers on the annual day for relations of CWI on 16 November, 2006.

New upper bounds for kissing in higher dimensions

Christine Bachoc (Université Bordeaux) and Frank Vallentin (Centrum voor Wiskunde en Informatica, Amsterdam), have found new upper bounds for 'kissing' in higher dimensions. In geometry the kissing number is the maximum number of non-overlapping unit balls that can simultaneously touch a central unit ball. In two dimensions the kissing number is six. You can clearly see this if you group euro coins around one central euro coin. The kissing number is only known for the dimensions 1, 2, 3, 4, 8 and 24.

Dion Gijswijt nominated for prestigious Tucker Prize

Dion Gijswijt, former PhD student of Lex Schrijver, was nominated for the A.W. Tucker Prize by the Mathematical Programming Society. The jury announced this during the International Symposium on Mathematical Programming (ISMP) 2006 in Rio de Janeiro on 31 July. The Tucker Prize is awarded every three years for 'an outstanding paper or thesis solely authored by a student'. Gijswijt was one of the three international finalists for his thesis, called 'Matrix algebras and semidefinite programming techniques for codes'. He was seconded at CWI from 2002 until 2005.

Invited lecture Bert Gerards at ICM 2006

Bert Gerards will give an invited lecture at the International Congress of Mathematicians (ICM) 2006 on 28 August in Madrid. It is a great honour to speak at ICM, the most important conference for mathematicians in the world with thousands of participants. The conference is organized every four years by the International Mathematical Union. Bert Gerards is cluster leader at CWI and part-time professor at the Technische Universiteit Eindhoven.

FOCUS and GLANCE subsidy for CWI

NWO granted two FOCUS subsidies to CWI researchers. FOCUS is the open part of the Bsik programme BRICKS, which has been developed by CWI and NWO Physical Sciences to stimulate fundamental computer science research. The programme will deliver important building blocks for the computer of the future.

Krzysztof Apt elected as Member of the Academia Europaea

Prof. dr. Krzysztof Apt (CWI and Universiteit van Amsterdam) has been elected as Member of the Academia Europaea in the Informatics Section on April 26, 2006. This section has 66 members of whom seven scientists come from the Netherlands. Other new members of this section are Prof. dr. Jan Bergstra (Universiteit van Amsterdam and Utrecht University) and Prof. dr.

Better train planning with mathematical models

Better planning for trains with mathematical models - this is the subject of the dissertation of Gabor Maroti of the Centrum voor Wiskunde en Informatica (CWI). Maroti studied several optimization models for tactical and operational planning and maintenance routing. He looked at efficiency, robustness (immunity for failures) and service level for clients - their chances to have a seat. With the models, NS can compare these aspects quantitatively and choose a good balance between them.

Prestigious prizes awarded to Lex Schrijver and Bert Gerards

On Monday, 18 August 2003, Lex Schrijver received the Dantzig prize for his complete work in optimization. Furthermore, he and Bert Gerards both received the Fulkerson prize during ISMP 2003 in Copenhagen. Schrijver is one of CWI's top researchers and holds a part-time professorship at the University of Amsterdam. Bert Gerards is theme leader at CWI and is also a part-time professor at the Technical University Eindhoven.

Lecture Edsger Dijkstra at CWI

Lecture Edsger Dijkstra On Tuesday, October 10, 2000, the famous Edsger Dijkstra will give a lecture at CWI, entitled: 'On avoiding avoidable case analyses'. Prof.dr. Dijkstra is Professor Emeritus of the University of Texas at Austin. In the list of most cited Dutch computer scientists on the Web, Dijkstra holds the second place.Abstract  On avoiding avoidable case analyses