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J. Walla, M. Ruthmair, G. Raidl:
"Solving a video-server load re-balancing problem by mixed integer programming and hybrid variable neighborhood search";
Talk: International Workshop on Hybrid Metaheuristics (HM), Udine, Italien; 2009-10-16 - 2009-10-17; in: "Hybrid Metaheuristics 2009, volume 5818 of LNCS", (2009), ISBN: 978-3-642-04917-0; 84 - 99.

A Video-on-Demand system usually consists of a large number
of independent video servers. In order to utilize network resources
as e ciently as possible the overall network load should be balanced
among the available servers. We consider a problem formulation based
on an estimation of the expected number of requests per movie during
the period of highest user interest. Apart from load balancing our
formulation also deals with the minimization of reorganization costs associated
with a newly obtained solution. We present two approaches to
solve this problem: an exact formulation as a mixed-integer linear program
(MIP) and a metaheuristic hybrid based on variable neighborhood
search (VNS). Among others the VNS features two special large neighborhood
structures searched using the MIP approach and by e ciently
calculating cyclic exchanges, respectively. While the MIP approach alone
is only able to obtain good solutions for instances involving few servers,
the hybrid VNS performs well especially also on larger instances.

http://publik.tuwien.ac.at/files/PubDat_181270.pdf