Contributed Session Fri.2.H 3503

Friday, 13:15 - 14:45 h, Room: H 3503

Cluster 23: Telecommunications & networks [...]

Markovian and randomized techniques for network optimization


Chair: Olivier Fercoq



Friday, 13:15 - 13:40 h, Room: H 3503, Talk 1

Olivier Fercoq
Polyhedral and ergodic control approaches to PageRank optimization and spam detection

Coauthors: Marianne Akian, Mustapha Bouhtou, Stéphane Gaubert


We study the PageRank optimization problem, which consists in finding an optimal outlink strategy for a web site. In each page, some hyperlinks are controlled while the others are not. We show that the problem can be modeled by a Markov decision process with ergodic reward, in which the webmaster determines the transition probabilities of websurfers. Although the number of actions may be exponential, we show that an associated polytope of transition measures has a concise representation, from which we deduce that the problem is solvable in polynomial time. Then we give an alternative application of PageRank optimization with the search engine's point of view: link spam detection and demotion. From seeds of hand-picked trusted and spam pages, we define a PageRank optimization problem where the cost function penalizes known spam pages and hyperlink removals. The invariant measure, called MaxRank, is interpreted as a modified PageRank vector, used to rank web pages. We show that the bias vector of the associated ergodic control problem is a measure of the "spamicity'' of each page. We introduce scalable algorithms that allowed us to perform numerical experiments on large size datasets.



Friday, 13:45 - 14:10 h, Room: H 3503, Talk 2

Arthur Tórgo Gómez
Development of a hybrid algorithm based on the application of metaheuristics on an Internet Protocol Television platform using Tabu Search (TS) and Genetic Algorithm (GA)

Coauthor: Carlos Alberto Weissheimer, Junior


The technology internet protocol television (IPTV) is a strong factor impacting on society. She has been exploited, by different means of transmission, for multimedia content delivery service based on internet protocol (IP). Currently, IPTV is the subject of several studies, and it can bring many benefits to society such as support for interactivity and increased interoperability in home networks. This paper presents the development and implementation of a hybrid
algorithm based on the application of metaheuristics on an IPTV
platform using tabu search (TS) and genetic algorithm (GA). This algorithm makes it possible analysis and study of the following parameters: baud rate, audio quality, number of customers and bandwidth. The focus is find the best parameters setting for the transmission given the characteristics of the IPTV client. After validation of the algorithm were performed experiments that help understand the dynamics of the system and enable find a good solution that can be simulated by the network simulator 3 (NS3).



Friday, 14:15 - 14:40 h, Room: H 3503, Talk 3

Cristobal Guzman
Network congestion control with Markovian multipath routing

Coauthor: Roberto Cominetti


In this paper we consider an integrated model for TCP/IP protocols with multipath routing. The model combines a network utility maximization for rate control based on end-to-end queuing delays, with a Markovian traffic equilibrium for routing based on total expected delays. We prove the existence of a unique equilibrium state which is characterized as the solution of an unconstrained strictly convex program. A distributed algorithm for solving this optimization problem is proposed, with a brief discussion of how it can be implemented by adapting the current Internet protocols.


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