Description
Leader of the group Networks and Optimization: Guido Schäfer.
In today’s society, complex systems surround us. From transport and traffic, to behavioral economics and operations management, real-world applications often demand that we identify simple, optimal solutions among a huge set of possibilities. Our research group Networks and Optimization (N&O) does fundamental research to tackle such challenging optimization problems.
We develop algorithmic methods to solve complex optimization problems efficiently. Our research provides efficient algorithms to some of the most challenging problems, for example, in planning, scheduling and routing. To come up with the best optimization algorithms, we combine and extend techniques from different disciplines in mathematics and computer science.
N&O covers a broad spectrum of optimization aspects. Our expertise ranges from discrete to continuous optimization and applies to centralized and decentralized settings. We focus on both problem-specific methods and universal toolkits to solve different types of optimization problems. The key in our investigations is to understand and exploit combinatorial structures, such as graphs, networks, lattices and matroids. Our research is of high scientific impact and contributes to various fields.
In several cooperations with industry partners, the algorithmic techniques that we develop in our group have proven useful to solve complex real-world problems. We are always interested in new algorithmic challenges arising in real-world applications and are open to new cooperations.
Watch our group video to get a glimpse of our activities.
Vacancies
PhD students in the research project “Polynomial Optimization, Efficiency through Moments and Algebra” (POEMA)
Centrum Wiskunde & Informatica (CWI) has vacancies in the Network and Optimization research group for two talented PhD students in the research project “Polynomial Optimization, Efficiency through Moments and Algebra” (POEMA).
PhD students on the subject of Towards a Quantitative Theory of Integer Programming
Centrum Wiskunde & Informatica (CWI) has a vacancy in the Networks & Optimization research group for two talented PhD students, on the subject of Towards a Quantitative Theory of Integer Programming.
Postdoc on the subject of Towards a Quantitative Theory of Integer Programming
Centrum Wiskunde & Informatica (CWI) has a vacancy in the Networks & Optimization research group for a talented Postdoc, on the subject of Towards a Quantitative Theory of Integer Programming.
News
CWI and ProRail predict railway incidents
Centrum Wiskunde & Informatica and ProRail recently started a research collaboration in the area of the handling of incidents at the Dutch railways. It concerns a public private partnership between CWI and ProRail striking up a four year period. The research is aimed at prevention and handling of a broad spectrum of railway incidents, like disturbance of the railway infrastructure, people walking on the tracks and collisions.
Large H2020 grant for optimisation research project ‘MINOA’
Recently, the EU granted the Mixed-Integer Non-Linear Optimisation Applications (MINOA) project, as part of the Horizon 2020 Research and Innovation Framework Programme. The project is a collaborative European Training Network, with 12 research partners, CWI being one of them.
Monique Laurent elected as Fellow of SIAM
CWI researcher Monique Laurent is elected as a Fellow of the international Society for Industrial and Applied Mathematics – SIAM. This prestigious Fellowship honours SIAM members who have made outstanding contributions to these fields. Laurent, who is a member of the management team of CWI and a professor at Tilburg University, receives the fellowship for her contributions to discrete and polynomial optimization and revealing interactions between them.
Rubicon grants for David de Laat and Alessandro Zocca
CWI researchers David de Laat and Alessandro Zocca both received an NWO Rubicon grant. De Laat will study new techniques to compute optimal packings at MIT for one year, and Zocca will study renewables and uncertainty in future power systems at Caltech for two years. NWO granted these subsidies to 22 young, highly promising research talents to gain international research experience at foreign top institutes.
Current events
N&O seminar: Jan-Hendrik Lange (Max-Planck-Institut für Informatik)
- 2019-01-23T14:00:00+01:00
- 2019-01-23T15:00:00+01:00
N&O seminar: Jan-Hendrik Lange (Max-Planck-Institut für Informatik)
Start: 2019-01-23 14:00:00+01:00 End: 2019-01-23 15:00:00+01:00
Everyone is welcome to attend this N&O lecture:
Speaker: Jan-Hendrik Lange (Max-Planck-Institut für Informatik)
Title: Combinatorial persistency criteria for multicut
The multicut problem (aka weighted correlation clustering) is a combinatorial optimization problem used to model, for instance, 2D- and 3D-segmentation tasks in computer vision. Despite its NP-hardness in the worst case, practical instances often exhibit substantial structural simplicity. This is indicated by high quality heuristic solutions and LP relaxations that are fairly tight. In this talk, we present methods that exploit these observations for the purpose of optimization. We introduce combinatorial persistency criteria to efficiently compute partial optimality guarantees on practical instances. Our techniques range from elementary criteria that can be checked enumeratively in a fast preprocessing step to more expensive criteria that incorporate both fast primal and dual heuristics. We demonstrate the effectiveness of our methods on common benchmarks as well as large biomedical 3D-segmentation instances.
Open Access: turning promises into reality
- 2019-01-25T14:30:00+01:00
- 2019-01-25T23:59:59+01:00
Open Access: turning promises into reality
Start: 2019-01-25 14:30:00+01:00 End: 2019-01-25 23:59:59+01:00
CWI organizes a meeting concerning Open Access aimed for a broad audience. It will be devoted to a discussion of Plan S, https://www.scienceeurope.org/wp-content/uploads/2018/09/Plan_S.pdf , an initiative for Open Access publishing, launched in September 2018, and supported by an international consortium of research funders, including NWO, and to two radical initiatives, SciPost, https://scipost.org/, and Open Research Central, https://openresearchcentral.org/ .
Programme 14:30 Prof. Jos Baeten (CWI, Amsterdam and ILLC, University of Amsterdam) Title: Implementing Plan-S
15:00 Prof. Jean-Sébastien Caux (Institute of Physics, University of Amsterdam) Title: Beyond Open Access: SciPost
15:45 Vitek Tracz (F1000, London, UK) Title: Beyond Open Access: Open Research Central - a model for universal platform for reporting research results
16:30 Discussion
17:00 Drinks
Please register (free of charge) by sending an email to: susanne.van.dam@cwi.nl
Early bird registration NMC 2019: deadline 31 December 2019
- 2019-04-23T09:00:00+02:00
- 2019-04-24T18:00:00+02:00
Early bird registration NMC 2019: deadline 31 December 2019
Start: 2019-04-23 09:00:00+02:00 End: 2019-04-24 18:00:00+02:00
On April 23-24, 2019, the Dutch Mathematical Congress (NMC 2019) will be held in the Congress Centre Koningshof (located in Veldhoven, close to Eindhoven).
Given the success of the first "NMC new style" earlier this year, we hope that in 2019 there will be even more participants. Once again we have compiled a very attractive programme with the following ingredients:
Plenary lectures by Barbara Gentz, Jan Hesthaven, Gábor Lugosi and Anke van Zuylen
Parallel sessions by the Gravitation programmes Networks and Quantum Software Consortium, and of pairs of clusters inspired by the new topics in the “Sectorplan”
A strategy session on the cluster evaluation and the “Sectorplan”
Speed dates with industry
Poster prize, KWG prize for PhD students, the Stieltjes prize and the new “innovation” prize for MSc students
Social programme with dinner and dance performance based on the ‘spurs of Lehmer’
The "early bird" registration period, giving you a discount of € 50,-, ends December 31st, so register now!
You can find more information and a link to the registration form.
With regards,
On behalf of the organising committee,
Evgeny Verbitsky (chair)
Members
Associated Members
Publications
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Chen, J.-J, Bansal, N, Chakraborty, S, & von der Brüggen, G. (2018). Packing sporadic real-time tasks on identical multiprocessor systems. In 29th International Symposium on Algorithms and Computation (pp. 71:1–71:14). doi:10.4230/LIPIcs.ISAAC.2018.71
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Dadush, D.N, Nikolov, A, Talwar, K, & Tomczak-Jaegermann, N. (2018). Balancing vectors in any norm. In Proceedings - Annual IEEE Symposium on Foundations of Computer Science, FOCS (pp. 1–10). doi:10.1109/FOCS.2018.00010
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Carvalho Rodrigues, F, Schäfer, G, & Xavier, E.C. (2018). On the effectiveness of connection tolls in fair cost facility location games. In Proceedings of the 19th Italian Conference on Theoretical Computer Science (pp. 36–47).
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van Heuven van Staereling, I.I. (2018). Tree decomposition methods for the periodic event scheduling problem. In OpenAccess Series in Informatics. doi:10.4230/OASIcs.ATMOS.2018.6
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Carstens, C.J, & Kleer, P.S. (2018). Speeding up switch Markov chains for sampling bipartite graphs with given degree sequence. In Approximation, Randomization, and Combinatorial Optimization. Algorithms and Techniques (APPROX/RANDOM 2018) (pp. 36:1–36:18). doi:10.4230/LIPIcs.APPROX-RANDOM.2018.36
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Amanatidis, G, Birmpas, G, & Markakis, V. (2018). Comparing approximate relaxations of envy-freeness. In IJCAI International Joint Conference on Artificial Intelligence (pp. 42–48).
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Dadush, D.N, & Huiberts, S. (2018). A friendly smoothed analysis of the simplex method. In Proceedings of the Annual ACM Symposium on Theory of Computing (pp. 214–227). doi:10.1145/3188745.3188826
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Bansal, N, Dadush, D.N, Garg, S, & Lovett, S. (2018). The Gram-Schmidt Walk: A Cure for the Banaszczyk Blues. In Proceedings of the 50th Annual ACM SIGACT Symposium on Theory of Computing, STOC 2018 (pp. 587–597). doi:10.1145/3188745.3188850
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Kamphorst, B. (2018, May 31). Heavy-traffic behaviour of scheduling policies in queues.
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Apt, K.R, & Wojtczak, D.K. (2018). Verification of distributed epistemic gossip protocols. Journal of Artificial Intelligence Research, 62, 101–132.
Current projects with external funding
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Continuous Methods in Discrete Optimization
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Verbeteren van de efficiency en prestatie van logistieke processen in de binnenvaart
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Wiskundecluster DIAMANT
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Approximation Algorithms, Quantum Information and Semidefinite Optimization (AQSO)
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Mixed-Integer Non-Linear Optimisation Applications (MINOA)
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Polynomial Optimization, Efficiency through Moments and Algebra (POEMA)
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Vóórkomen en voorkómen van incidenten op het spoor (PPS Prorail)
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Towards a Quantitative Theory of Integer Programming (QIP)
Related partners
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Alma Mater Studiorum-Universita di Bologna
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Alpen-Adria-Universität Klagenfurt
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CNR Pisa
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CNRS
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CTVrede
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IBM
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INRIA
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Prorail
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Rheinische Friedrich-Wilhelmus Universitaet Bonn
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Technische Universität Dortmund
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Tilburg University
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Tromsø, Norway
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Universita degli Studi di Firenze
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Universität Konstanz
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University of Birmingham