Description

Leader of the group Networks and Optimization: Daniel Dadush.

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.

 

Video about our collaboration with ProRail (in Dutch)

 

READ MORE...

Vacancies

No vacancies currently.

News

Current events

Dutch Seminar on Optimization (online series) with Ilker Birbil (University of Amsterdam)

  • 2022-08-25T16:00:00+02:00
  • 2022-08-25T17:00:00+02:00
August 25 Thursday

Start: 2022-08-25 16:00:00+02:00 End: 2022-08-25 17:00:00+02:00

Online seminar

The Dutch Seminar on Optimization is an initiative to bring together researchers from the Netherlands and beyond, with topics that are centered around Optimization in a broad sense. We would like to invite all researchers, especially also PhD students, who are working on related topics to join the events. We hereby announce the following talk, given by Ilker Birbil (University of Amsterdam):

Speaker: Ilker Birbil (University of Amsterdam)
Title: Counterfactual Explanations Using Optimization With Constraint Learning
Date: Thursday 25th August, 4pm CET

Abstract:
Counterfactual explanations embody one of the many interpretability techniques that receive increasing attention from the machine learning community. Their potential to make model predictions more sensible to the user is considered to be invaluable. To increase their adoption in practice, several criteria that counterfactual explanations should adhere to have been put forward in the literature. We propose counterfactual explanations using optimization with constraint learning, a generic and flexible approach that addresses all these criteria and allows room for further extensions. Specifically, we discuss how we can leverage an optimization with constraint learning framework for the generation of counterfactual explanations, and how components of this framework readily map to the criteria. We also propose new novel modeling approaches to address data manifold closeness and diversity, which are two key criteria for practical counterfactual explanations. We test our approaches on several datasets and present our results in a case study. Compared to a current state-of-the-art method, our modeling approach has shown an overall superior performance in terms of several evaluation metrics proposed in related work while allowing more room for flexibility.

Workshop on Semidefinite and Polynomial Optimization (Semester Programme)

  • 2022-08-29T00:00:00+02:00
  • 2022-09-02T23:59:59+02:00
August 29 Monday

Start: 2022-08-29 00:00:00+02:00 End: 2022-09-02 23:59:59+02:00

Amsterdam Science Park Congress Centre, Euler room

This workshop is dedicated to recent developments in semidefinite and polynomial optimization, and their applications in combinatorial and continuous optimization, discrete geometry and quantum information. The program (under construction) will consist of invited lectures by experts in the field. It will also feature lectures by younger researchers and ample time will be left for free discussions. 

This workshop is co-organized by Jop Briët and Monique Laurent.

Here you can find more information on the program of CWI's Semidefinite and Polynomial Optimization Workshop.

This workshop is now fully booked. Please contact the organizers directly if you like to join.

 

 

 

Workshop on Solving Polynomial Equations and Applications (Semester Programme)

  • 2022-10-05T00:00:00+02:00
  • 2022-10-07T23:59:59+02:00
October 5 Wednesday

Start: 2022-10-05 00:00:00+02:00 End: 2022-10-07 23:59:59+02:00

CWI

Polynomial equations are at the heart of many problems in pure and applied mathematics. They form a powerful tool for modelling nonlinear phenomena in the sciences. Application areas range from robotics, chemistry and computer vision to quantum physics and statistics. Recent progress has made it possible to reliably solve challenging polynomial equations arising in such practical contexts. This workshop will feature a friendly introduction to existing methods, presentations of the latest software tools and research talks by experts in the field. The focus will be on new trends and methodology, as well as applications in the sciences.

This workshop is co-organized by Monique Laurent and Simon Telen.

Here you can find more information on the program of CWI's Solving Polynomial Equations and Applications workshop.

Please register here.

 

CWI Lectures on Algebraic and Geometric Methods in Optimization (2022)

  • 2022-11-16T13:00:00+01:00
  • 2022-11-16T18:00:00+01:00
November 16 Wednesday

Start: 2022-11-16 13:00:00+01:00 End: 2022-11-16 18:00:00+01:00

In honor of Monique Laurent’s contributions to research in the area of Polynomial Optimization

How to compose a portfolio ensuring maximum revenue while minimizing risk? How to control trajectories of solutions in dynamical systems? How to find the best sphere packing or the minimum energy of an interacting particle system? How to find optimal power flows in energy networks?

Such difficult optimization problems arise in diverse fields and application areas, such as operations research, discrete geometry, machine learning, theoretical computer science, and control theory.

These CWI Lectures are devoted to novel solution methods that combine dedicated algebraic and geometric approaches and sophisticated computational tools from mathematics and computer science.

Various aspects will be covered by four world-leading experts: Amir Ali Ahmadi (Princeton University), Etienne de Klerk (Tilburg University), Rekha Thomas (University of Washington), and Frank Vallentin (Universität zu Köln).

During the event, we will celebrate Monique Laurent’s appointment as a CWI Fellow for her contributions to research in the area of Polynomial Optimization. The theme of this year’s lectures was chosen in honor of Monique’s work.

The lectures are intended for a broad mathematical audience and in 2022 the program committee consists of Daniel Dadush and Guido Schäfer (Networks and Optimization Group).

Preliminary program:
13.00–13.10 Welcome
13.10–13.55 Etienne de Klerk
13.55–14.40 Frank Vallentin
14.40–15.15 Break
15.15–16.00 Amir Ali Ahmadi
16.00–16.45 Rekha Thomas
16.45–16.50 Closing
16.50–18.00 Drinks

More information about the speakers will be made available soon. Registration will open early September.

For inquiries and further details about the lectures, please contact event coordinator Daniëlle Kollerie (D.C.Kollerie@cwi.nl).

Workshop on Polynomial Optimization and Applications in Control and Energy (Semester Programme)

  • 2022-11-17T00:00:00+01:00
  • 2022-11-18T23:59:59+01:00
November 17 Thursday

Start: 2022-11-17 00:00:00+01:00 End: 2022-11-18 23:59:59+01:00

CWI

This workshop is devoted to the application of polynomial optimization methods in the analysis and control of dynamical systems and energy networks. The polynomial optimization approach offers a powerful framework to model hard nonconvex, nonlinear control problems as infinite dimensional linear optimization problems over measure spaces. The rich interplay between functional analysis and operator theory, and real algebraic geometry, underlies the nowadays well-known moment/sum-of-squares hierarchy of relaxations, that allows to efficiently obtain converging sequences of bounds. This approach has also been recently developed to attack large optimal power flow problems in large electrical networks. The program (under construction) will feature lectures by experts in the field and ample time will be left for discussions.

This workshop is co-organized by Monique Laurent and Bert Zwart.

Here you can find more information on the program of CWI's Polynomial Optimization and Applications in Control and Energy workshop.

Please register here.

Members

Associated Members

Publications

Current projects with external funding

  • Smart Heuristic Problem Optimization ()
  • Mixed-Integer Non-Linear Optimisation Applications (MINOA)
  • New frontiers in numerical nonlinear algebra (None)
  • Optimization for and with Machine Learning (OPTIMAL)
  • Polynomial Optimization, Efficiency through Moments and Algebra (POEMA)
  • Towards a Quantitative Theory of Integer Programming (QIP)

Related partners

  • Alma Mater Studiorum-Universita di Bologna
  • Alpen-Adria-Universität Klagenfurt
  • CNR Pisa
  • CNRS
  • Dassault Systèmes B.V.
  • IBM
  • INRIA
  • Rheinische Friedrich-Wilhelmus Universitaet Bonn
  • Technische Universität Dortmund
  • Tilburg University
  • Tromsø, Norway
  • Universita degli Studi di Firenze
  • Universität Konstanz
  • University of Birmingham
  • Universiteit van Tilburg