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Ph.D de

Ph.D
Group : Networking & Stochastic and Combinatorial Optimization

Programmation semi-définie positive : méthodes et algorithmes pour le management d'énergie

Starts on 14/12/2009
Advisor : LISSER, Abdel

Funding : Autre financement à préciser
Affiliation : Université Paris-Saclay
Laboratory : EDF puis LRI

Defended on 26/09/2013, committee :
Alain Denise, Professeur, Université Paris Sud (examinateur)
Didier Henrion, Directeur de Recherche, LAAS CNRS - Toulouse (rapporteur)
Abdel Lisser, Professeur, Université Paris Sud (directeur de thèse)
Abdelatif Mansouri, Professeur, Université Cadi Ayyad - Marrakech (examinateur)
Michel Minoux, Professeur, Université Paris 6 (examinateur)
Franz Rendl, Professeur, University of Klagenfurt - Austria (rapporteur)
Riadh Zorgati, Docteur, EDF R&D (rapporteur)

Research activities :

Abstract :
The present thesis aims at exploring the potentialities of a powerful optimization technique, namely Semidefinite Programming, for addressing some difficult problems of energy management.
We pursue two main objectives. The first one consists of using SDP to provide tight relaxations of combinatorial and quadratic problems. A first relaxation, called “standard” can be derived in a generic way but it is generally desirable to reinforce them, by means of tailor-made tools or in a systematic fashion. These two approaches are implemented on different models of the Nuclear Outages Scheduling Problem, a famous combinatorial problem. We conclude this topic by experimenting the Lasserre's hierarchy on this problem, leading to a sequence of semidefinite relaxations whose optimal values tends to the optimal value of the initial problem.
The second objective deals with the use of SDP for the treatment of uncertainty. We investigate an original approach called “distributionnally robust optimization”, that can be seen as a compromise between stochastic and robust optimization and admits approximations under the form of a SDP. We compare the benefits of this method w.r.t classical approaches on a demand/supply equilibrium problem. Finally, we propose a scheme for deriving SDP relaxations of MISOCP and we report promising computational results indicating that the semidefinite relaxation improves significantly the continuous relaxation, while requiring a reasonable computational effort.
SDP therefore proves to be a promising optimization method that offers great opportunities for innovation in energy management.

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MICRO VISUALIZATIONS: DESIGN AND ANALYSIS OF VISUALIZATIONS FOR SMALL DISPLAY SPACES
The topic of this habilitation is the study of very small data visualizations, micro visualizations, in display contexts that can only dedicate minimal rendering space for data representations. For several years, together with my collaborators, I have been studying human perception, interaction, and analysis with micro visualizations in multiple contexts. In this document I bring together three of my research streams related to micro visualizations: data glyphs, where my joint research focused on studying the perception of small-multiple micro visualizations, word-scale visualizations, where my joint research focused on small visualizations embedded in text-documents, and small mobile data visualizations for smartwatches or fitness trackers. I consider these types of small visualizations together under the umbrella term ``micro visualizations.'' Micro visualizations are useful in multiple visualization contexts and I have been working towards a better understanding of the complexities involved in designing and using micro visualizations. Here, I define the term micro visualization, summarize my own and other past research and design guidelines and outline several design spaces for different types of micro visualizations based on some of the work I was involved in since my PhD.