Projects
Some research projects I am or was involved in. (Not quite up to date, sorry.)
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Since starting as a PhD student I was interested in stochastic scheduling problems, that is problems where the processing times of jobs are uncertain, but in the analysis of algorithms we assume that the adversary suffers from the same uncertainty. Part of my PhD thesis was on that topic, too. Over the years, I regularly came back to this problem. My work on this problem started in around 1999 with LP-based approximation algorithms (see this J. ACM paper). We also adressed problems with precedence constraints (see this SICOMP paper). In 2006 we realized that we could extend to problems where jobs appear online (see this Math of OR paper). On a Dagstuhl workshop in 2013, we found out how to handle also the more general unrelated machine model (see this Math of OR paper). More recently on a 2016 sabbatical at UC Berkeley, we found that even greedy algorithms do the job; this work will appear at Math of OR.
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In a cooperation with NPU in Xi'an (China), and co-funded by the NSFC, PhD student Xianghui Li graduated in 2019 on the topic Values for Cooperative Games with Restricted Coalition Formation. At the UT, Xianghui was jointly supervised by Reinoud Joosten and myself.
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The project Mechanisms for Decentralized Service Systems was a PhD project about the analysis of the effect of decentralization on service systems, leading to questions about the price of anarchy in network routing or throughput scheduling models, among others. The PhD student who graduated on this project in 2016 is Jasper de Jong, with a PhD thesis on Quality of Equilibria in Resource Allocation Games.
Next to conference papers at CIAC, twice at WINE and SAGT, this research has been (or will be) published in
Mathematics of Operations Research, the
International Journal of Game Theory, and
Operations Research Letters.
Jasper is now docent (teaching staff) ate the University of Twente.
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In a collaboration with a research group in bioengineering at the University of Twente, we tried to answer the question which physical topology would be best suited for the development of stem cells into bone cells. The project was realized in the form of an extended MSc project, with some funding from KNAW (a so-called Meester-Gezel project). The student who graduated on this project is Kamiel Cornelissen. Our findings have been published in a joint paper at PNAS, the Proceedings of the National Academy of Sciences of the USA. Kamiel later (in 2015) finished a Phd at the University of Twente on another topic, and now works for ORTEC.
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The project Design and Complexity of Optimal Mechanisms was a PhD project about optimal mechanism design, mostly applied in the context of scheduling problems. The project was funded by research school CTIT of the University of Twente from 2010-2015. The PhD student who graduated on the project is Ruben Hoeksma, with a PhD thesis on Mechanisms for scheduling games with selfish players. The underlying papers have been published in conferences WAOA, IPCO, and ISCO, and finally in the journals
Operations Research,
Discrete Optimization, and
Discrete Applied Mathematics. Ruben is now PostDoc at the University of Bremen in the group of Nicole Megow.
Before I moved to University of Twente, I worked as an assistant/associate professor at the Faculty of Economics and Business Administration at Maastricht University. There I was involved in the following research projects, among others.
- The project Scheduling with Resource Dependent Processing Times is a cooperation between Alexander Grigoriev (Maastricht University), and Maxim Sviridenko (now at Yahoo, New York), and myself. The project was partially funded by the Maastricht Research School of Economics of Technology and Organizations (METEOR). We published papers in
Mathematical Programming and
Discrete Optimization. Earlier conference papers appeared in IPCO and APPROX.
- The project Pricing Problems in Distributed Settings was a research project funded the
Maastricht Research School of Economics of Technology and Organizations (METEOR). The project was funded from 2005 till 2009.
The researcher employed on this
project was Joyce van Loon, she returned to Maastricht University as an expert for educational development and research. Her PhD thesis from 2009 is titled Algorithmic Pricing.
Among others, we published some joint papers on this topic on conferences ESA, WAOA, WG and WINE, and in the journals
4OR,
Networks, and
Operations Research Letters.
- The project Local Decision in Decentralized Planning Environments was a research project funded by the Netherlands Organization for Scientific Research (NWO). The project was funded from 2004 till 2009.
The researcher who graduated on this project is Birgit Heydenreich, her PhD thesis from 2009 is titled
Graphs, Mechanisms and Scheduling.
We published joint papers on conferences like SWAT, CTW, and WINE, and in the journals
Production and Operations Management,
Journal of Scheduling,
Operations Research, and
Econometrica.
Birgit now works as consultant for TNG Technology Consulting.
And before working at Maastricht University, I worked as a research assistant at the Institute of Mathematics at the Technische Universität Berlin. There I was also involved in several research projects, partly with industry cooperations.
- The project
Algorithms
for Scheduling Scarce Recources in Chemical Engineering
was funded by the Bundesministerium für
Bildung und Forschung (bmb+f)
within the program Mathematical Methods for Solving Problems in
Industry and Business from July 1997 to August 2000.
This project addresses scheduling problems
which arise in chemical production processes; it is based on a cooperation
with Josef Kallrath at
BASF AG Ludwigshafen.
You may want to have a look at the resulting paper Scheduling Scarce Resources in Chemical Enginering which summarizes some of the outcomes of this project. While working on this problem, we also published a paper on project scheduling in
Management Science, and another one in
Mathematical Programming.
- The project Polyhedral Methods in Stochastic Scheduling (1999-2001) was funded by
the German-Israeli Foundation for Scientific Research and Development
(GIF). It is a German-Israeli cooperation
which addresses polyhedral approaches to scheduling under uncertainty. This topic was also part of my PhD project, and my work on stochastic scheduling has back then led to publications in the
Journal of the ACM (Association for Computing Machinery),
SIAM Journal of Computing,
and
Operations Research Letters.
- The project Automated Staff Scheduling (2000-2002) was a project
funded by the ATOSS Software AG in München, Germany. Together with Frederik Stork, I was the project manager. The core of this project
was the development and implementation of
efficient algorithms for different problems which arise in automated
staff scheduling. Eventually, the cooperation aims at providing an interactive
software module which allows to generate and manipulate
staff assignments automatically, according to the individual needs of staff, and objectives
of the scheduler. This project documentation tells a bit of what we did.