events and seminars

MSc Seminar on June 22, 12.45-13.30

The speakers will be:

1.

Arwyn Goos, “A model for infrastructure projects with uncertainty in costs and revenues and the option to abandon the project during construction”

2.

Rico van Lingen, “Adaptive testing with the SPRT for two non-standard IRT models”

For a list of MSc seminars, click here .

Healthcare Operations Research Summer School in Twente
July 21 – 25, 2017
University of Twente, Enschede, the Netherlands

We are excited to announce a special summer school on Healthcare Operations Research this summer at the University of Twente, the Netherlands! The event targets PhD students working on OR applications focused on improving healthcare. Participants will learn state-of-the-art OR techniques taught by renowned international professors, learn about how to successfully engage with the healthcare practice, and meet other PhD students from around the world. The program includes a wide variety of components including technical lectures, tutorials, inspiring seminars, interactive activities and a design competition of a serious game that demonstrates a healthcare OR/OM concept to healthcare professionals. The total workload of the summer school is 2 European Credits (2 ECs = 56 hours), consisting of preparation and contact hours. For more information and registration please follow this link.


Symposium

For a list of seminars and conferences, click here.

Dinsdag Seminar

Dinsdag Seminar on May 30, 12.45-13.30

The degree value for games with communication structure

Speaker:

Berksan Şerbetci

Affiliation:

UT-EWI-SOR

Abstract:

We consider caching in cellular networks in which each base station is equipped with a cache that can store a limited number of files. The popularity of the files is known and the goal is to place files in the caches such that the probability that a user at an arbitrary location in the plane will find the file that she requires in one of the covering caches is maximized.


We develop distributed asynchronous algorithms for deciding which contents to store in which cache. Such cooperative algorithms require communication only between caches with overlapping coverage areas and can operate in asynchronous manner. The development of the algorithms is principally based on an observation that the problem can be viewed as a potential game. Our basic algorithm is derived from the best response dynamics. We demonstrate that the complexity of each best response step is independent of the number of files, linear in the cache capacity and linear in the maximum number of base stations that cover a certain area. Then, we show that the overall algorithm complexity for a discrete cache placement is polynomial in both network size and catalog size. In practical examples, the algorithm converges in just a few iterations. Also, in most cases of interest, the basic algorithm finds the best Nash equilibrium corresponding to the global optimum. We provide two extensions of our basic algorithm based on stochastic and deterministic simulated annealing which find the global optimum.


Finally, we demonstrate the hit probability evolution on real and synthetic networks numerically and show that our distributed caching algorithm performs significantly better than storing the most popular content, probabilistic content placement policy and Multi-LRU caching policies.


Joint work with Jasper Goseling and Konstantin Avrachenkov (INRIA Sophia Antipolis, France)

Dinsdag Seminar on Thursday November 19, 12.45-13.30 in Carre 3D

For a list of Dinsdag seminars, click here.