Fabrice Rossi

  1. A Discussion on Parallelization Schemes for Stochastic Vector Quantization Algorithms.

    Authors: Benoît Patra, Fabrice Rossi, Matthieu Durut
    Subjects: Machine Learning
    Abstract

    This paper studies parallelization schemes for stochastic Vector Quantization
    algorithms in order to obtain time speed-ups using distributed resources. We
    show that the most intuitive parallelization scheme does not lead to better
    performances than the sequential algorithm. Another distributed scheme is
    therefore introduced which obtains the expected speed-ups. Then, it is improved
    to fit implementation on distributed architectures where communications are
    slow and inter-machines synchronization too costly.

  2. Modularity-Based Clustering for Network-Constrained Trajectories.

    Authors: Fabrice Rossi, Mohamed Khalil El Mahrsi
    Subjects: Machine Learning
    Abstract

    We present a novel clustering approach for moving object trajectories that
    are constrained by an underlying road network. The approach builds a similarity
    graph based on these trajectories then uses modularity-optimization hiearchical
    graph clustering to regroup trajectories with similar profiles. Our
    experimental study shows the superiority of the proposed approach over classic
    hierarchical clustering and gives a brief insight to visualization of the
    clustering results.

  3. Dissimilarity Clustering by Hierarchical Multi-Level Refinement.

    Authors: Fabrice Rossi, Brieuc Conan-Guez
    Subjects: Machine Learning
    Abstract

    We introduce in this paper a new way of optimizing the natural extension of
    the quantization error using in k-means clustering to dissimilarity data. The
    proposed method is based on hierarchical clustering analysis combined with
    multi-level heuristic refinement. The method is computationally efficient and
    achieves better quantization errors than the

  4. Consistency of functional learning methods based on derivatives.

    Authors: Fabrice Rossi, Nathalie Villa-Vialaneix
    Subjects: Statistics
    Abstract

    In some real world applications, such as spectrometry, functional models
    achieve better predictive performances if they work on the derivatives of order
    m of their inputs rather than on the original functions. As a consequence, the
    use of derivatives is a common practice in Functional Data Analysis, despite a
    lack of theoretical guarantees on the asymptotically achievable performances of
    a derivative based model.

  5. Optimizing an Organized Modularity Measure for Topographic Graph Clustering: a Deterministic Annealing Approach.

    Authors: Fabrice Rossi, Nathalie Villa-Vialaneix
    Subjects: Machine Learning
    Abstract

    This paper proposes an organized generalization of Newman and Girvan's
    modularity measure for graph clustering. Optimized via a deterministic
    annealing scheme, this measure produces topologically ordered graph clusterings
    that lead to faithful and readable graph representations based on clustering
    induced graphs. Topographic graph clustering provides an alternative to more
    classical solutions in which a standard graph clustering method is applied to
    build a simpler graph that is then represented with a graph layout algorithm.

  6. Exploratory Analysis of Functional Data via Clustering and Optimal Segmentation.

    Authors: Fabrice Rossi, Georges Hébrail, Bernard Hugueney, Yves Lechevallier
    Subjects: Machine Learning
    Abstract

    We propose in this paper an exploratory analysis algorithm for functional
    data. The method partitions a set of functions into $K$ clusters and represents
    each cluster by a simple prototype (e.g., piecewise constant). The total number
    of segments in the prototypes, $P$, is chosen by the user and optimally
    distributed among the clusters via two dynamic programming algorithms. The
    practical relevance of the method is shown on two real world datasets.

  7. Median topographic maps for biomedical data sets.

    Authors: Fabrice Rossi, Barbara Hammer, Alexander Hasenfuß
    Subjects: Learning
    Abstract

    Median clustering extends popular neural data analysis methods such as the
    self-organizing map or neural gas to general data structures given by a
    dissimilarity matrix only. This offers flexible and robust global data
    inspection methods which are particularly suited for a variety of data as
    occurs in biomedical domains. In this chapter, we give an overview about median
    clustering and its properties and extensions, with a particular focus on
    efficient implementations adapted to large scale data analysis.

  8. Advances in Feature Selection with Mutual Information.

    Authors: Michel Verleysen, Fabrice Rossi, Damien François
    Subjects: Learning
    Abstract

    The selection of features that are relevant for a prediction or
    classification problem is an important problem in many domains involving
    high-dimensional data. Selecting features helps fighting the curse of
    dimensionality, improving the performances of prediction or classification
    methods, and interpreting the application. In a nonlinear context, the mutual
    information is widely used as relevance criterion for features and sets of
    features.

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