Nouvelles méthodes pour l’apprentissage multi-objectifs

Multi-objective problems arise in many real world scenarios where one has to find an optimal solution considering the trade-off between different competing objectives. Typical examples of multi-objective problems arise in classification, information retrieval, dictionary learning, online learning etc. In this thesis, we study and propose algorithms for multi-objective machine learning problems. We give many interesting examples of multi-objective learning problems which are actively persuaded by the research community to motivate our work. Majority of the state of the art algorithms proposed for multi-objective learning comes under what is called “scalarization method”, an efficient algorithm for solving multi-objective optimization problems. Having motivated our work, we study two multi-objective learning tasks in detail. In the first task, we study the problem of finding the optimal classifier for multivariate performance measures. The problem is studied very actively and recent papers have proposed many algorithms in different classification settings. We study the problem as finding an optimal trade-off between different classification errors, and propose an algorithm based on cost-sensitive classification. In the second task, we study the problem of diverse ranking in information retrieval tasks, in particular recommender systems. We propose an algorithm for diverse ranking making use of the domain specific information, and formulating the problem as a submodular maximization problem for coverage maximization in a weighted similarity graph. Finally, we conclude that scalarization based algorithms works well for multi-objective learning problems. But when considering algorithms for multi-objective learning problems, scalarization need not be the “to go” approach. It is very important to consider the domain specific information and objective functions. We end this thesis by proposing some of the immediate future work, which are currently being experimented, and some of the short term future work which we plan to carry out.Les problèmes multi-objectifs se posent dans plusieurs scénarios réels dans le monde où on doit trouver une solution optimale qui soit un compromis entre les différents objectifs en compétition. Dans cette thèse, on étudie et on propose des algorithmes pour traiter les problèmes des machines d’apprentissage multi-objectif. On étudie deux méthodes d’apprentissage multi-objectif en détail. Dans la première méthode, on étudie le problème de trouver le classifieur optimal pour réaliser des mesures de performances multivariées. Dans la seconde méthode, on étudie le problème de classer des informations diverses dans les missions de recherche des informations