EPFL Statistics Seminar

  • Dr. Finn Lindgren

    The University of Edinburgh
    Friday, February 22, 2019
    Time 15:15 - Room MA10

    Title: Quantifying the uncertainty of contour maps

    Abstract

    Contour maps are ubiquitous for visualising estimated spatial fields, but the uncertainty associated with such maps has been given a surprisingly small amount of attention. The question is closely connected with the dual problem of constructing credible regions for excursion sets, which leads to a more stringent formulation of the problem. With computational implementations, we can answer questions such as "How many or few contours levels is it reasonable to use, given the inherent uncertainty?". I will discuss these issues in particular in the context of Bayesian latent Gaussian random field models estimated with Integrated Nested Laplace Approximations.

  • Dr. David Kraus

    Masaryk University
    Thursday, February 28, 2019
    Time 14:15 - Room MA12

    Title: Regularized classification of functional data under incomplete observation

    Abstract

    Classification of functional data into two groups by linear classifiers is considered on the basis of one-dimensional projections of functions. Finding the best classifier is seen as an optimization problem that can be approximately solved by regularization methods, e.g., the conjugate gradient method with early stopping, the principal component method and the ridge method. We study the empirical version with finite training samples consisting of incomplete functions observed on different subsets of the domain and show that the optimal, possibly zero, misclassification probability can be achieved in the limit along a possibly non-convergent empirical regularization path. We propose a domain extension and selection procedure that finds the best domain beyond the common observation domain of all curves. In a simulation study we compare the different regularization methods and investigate the performance of domain selection. Our methodology is illustrated on a medical data set, where we observe a substantial improvement of classification accuracy due to domain extension.

    The talk is based on joint work with Marco Stefanucci.

  • Dr. Phyllis Wan

    Erasmus University Rotterdam
    Friday, March 15, 2019
    Time 14:15 - Room CM 1 113

    Title: TBA

    Abstract

    TBA

  • Dr. Guillaume Obozinski

    Swiss Data Science Center, EPFL
    Friday, April 12, 2019
    Time 14:15 - Room CM 1 113

    Title: TBA

    Abstract

    TBA

  • Prof. Rainer von Sachs

    UC Louvain
    Thursday, May 23, 2019
    Time 14:15 - Room CM 1 113

    Title: TBA

    Abstract

    TBA

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