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In the context of team Cornet’s seminars, Shane Mannion (University of Limerick) will present his research work on Correlations on complex networks and their degree distributions, on April 5, 2023, at 11:35 in the meeting room. Abstract: First we look at long range correlations in complex networks. The assortativity of a network, that is, the correlation between properties of neighboring nodes can have important practical implications. For example, a targeted vaccination program will be less effective in an assortative social network (where high-degree people mix with others of high degree). We are concerned with whether these correlations between nodes extend to nodes that are separated by more than a single edge. In this talk I will discuss how the correlation between properties of connected nodes in a social network changes as the distances between those nodes increases. This lead us to research on fitting degree distributions, where we introduce a method for fitting to the degree distributions of complex network datasets, such that the most appropriate distribution from a set of candidate distributions is chosen while maximizing the portion of the distribution to which the model is fit. Current methods for fitting to degree distributions in the literature are inconsistent Plus d'infos

In the context of team Cornet’s seminars, Rachid Elazouzi (LIA) will present his research work on Controlled Matching Game for Resource Allocation and User Association in WLANs, on March 31, 2023, at 11:35 in the meeting room. Abstract: In multi-rate IEEE 802.11 WLANs, the traditional user association based on the strongest received signal and the well known anomaly of the MAC protocol can lead to overloaded Access Points (APs), and poor or heterogeneous performance. Our goal is to propose an alternative game-theoretic approach for association. We model the joint resource allocation and user association as a matching game with complementarities and peer effects consisting of selfish players solely interested in their individual throughputs. Using recent game-theoretic results we first show that various resource sharing protocols actually fall in the scope of the set of stability-inducing resource allocation schemes. The game makes an extensive use of the Nash bargaining and some of its related properties that allow to control the incentives of the players. We show that the proposed mechanism can greatly improve the efficiency of 802.11 with heterogeneous nodes and reduce the negative impact of peer effects such as its MAC anomaly. The mechanism can be implemented as a virtual Plus d'infos

In the context of team Cornet’s seminars, Mandar Datar (LIA) will present her research work on Online algorithms in games and convex optimization, on March 10, 2023, at 11:35 in the meeting room.

In the context of team Cornet’s seminars, Panagiotis Andrianesis (Boston University) will present his research work on Optimal Distributed Energy Resource Coordination: A Hierarchical Decomposition Method Based on Distribution Locational Marginal Costs, on February 23, 2023, at 11:35 in the meeting room. Abstract: In this work, we consider the day-ahead operational planning problem of a radial distribution network hosting Distributed Energy Resources (DERs) including rooftop solar and storage-like loads, such as electric vehicles. We present a novel hierarchical decomposition method that is based on a centralized AC Optimal Power Flow (AC OPF) problem interacting iteratively with self-dispatching DER problems adapting to real and reactive power Distribution Locational Marginal Costs. We illustrate the applicability and tractability of the proposed method on an actual distribution feeder, while modeling the full complexity of spatiotemporal DER capabilities and preferences, and accounting for instances of non-exact AC OPF convex relaxations. We show that the proposed method achieves optimal Grid-DER coordination, by successively improving feasible AC OPF solutions, and discovers spatiotemporally varying marginal costs in distribution networks that are key to optimal DER scheduling by modeling losses, ampacity and voltage congestion, and, most importantly, dynamic asset degradation.

In the context of team Cornet’s seminars, Sébastien De Valeriola (Free University of Brussels) will present his research work on “Fading Footprints in the Sand”: Analysis of Historical Networks and Robustness of Centrality Metrics, on February 10, 2023, at 11:35 in the room S6. Abstract: In this presentation, we consider centrality measures in their use in the analysis of historical networks. Since the sources used by historians to construct such networks are inherently incomplete and imperfect, it is necessary to take into account the robustness of these metrics as much as possible, i.e., their stability in the face of the vagaries that time has subjected historical documents to. To study this, we apply a battery of tests to three networks constructed from medieval history data. The first is a network of political history, representing the connections among the key figures in the conflict for the episcopal seat of Cambrai in the 11th century. The second is a network of socio-economic history, describing credit relationships among merchants in Ypres in the 13th century. The third is a hagiographical network depicting the connections between the lives of saints often compiled together in manuscripts. These tests are designed to simulate the processes of Plus d'infos

In the context of team Cornet’s seminars, Felipe Albuquerque (LIA/Espace) will present his research work on January 13, 2023, at 11:35 in the meeting room. Abstract: Frequently, social network information has been used to solve applications in Operation Research, such as the Team Formation Problem, whose goal is to find a subset of the workers that collectively cover a set of skills and can communicate effectively with each other. We use the Structural Balance Theory to define the compatibility between pairs of workers in the same team. For such, the social networks are represented by signed graphs, and the compatibility metric is calculated from the analysis of possible positive paths between pairs of distinct vertices. To solve this new version of the problem, we introduce an Integer Linear Programming formulation and a decomposition for it. We present an analysis of the performed computational tests that prove the potential efficiency of the decomposition proposed.

In the context of team Cornet’s seminars, Olivier Tsemogne (LIA) will present his research work on Game Theory for Cyber Deception against Network SIR Epidemics, on December 12, 2022, at 11:35 in the meeting room. Abstract: One of the deleterious aspects of the evolution of information and communication technologies is the combination of efficiency and effectiveness in the malware spread, which clearly constitutes a threat to the security of the users of these technologies. The term “user” here covers individuals, companies, governmental or non-governmental organizations, states, in short, any person or group of persons who communicate using the new technologies. Among these threats, we can cite rumors in a social network and the stealthy recruitment of naive users into a cyber terrorist army capable, for example, of causing serious damage to a company whose services are used by these same users. In these two cases, as in many others, users, tricked by skilled experts, participate against their will and against their own interest in a cyber attack of which they are not aware, the bearer of the attack being deception. Moreover, cybercriminals, unlike cyber defenders, violate the rules of privacy and are therefore the best, if not the only, informed Plus d'infos