NumPI February 2016

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3 participants
4 discussions

Reminder: Optimization & Numerical Analysis seminars: Brugiapaglia
by Federico Poloni 20 Jun '16

20 Jun '16

Speaker: Simone Brugiapaglia Affiliation: Politecnico di Milano --- Laboratory for Modeling and Scientific Computing MOX Time: Tuesday, December 15, 11 am Place: Sala Seminari Est, Dipartimento di Informatica, Università di Pisa Title: CORSING: Sparse approximation of PDEs based on Compressed Sensing Abstract: We present a novel method for the numerical approximation of PDEs, motivated by recent developments in sparse representation, and particularly by compressed sensing. We named this approach CORSING (COmpRessed SolvING). Establishing an analogy between the sampling of a signal and the Petrov-Galerkin discretization of a PDE, the CORSING method can recover the best s-term approximation to the solution with respect to N suitable trial functions, with s<<N, by evaluating the bilinear form associated with the PDE against a randomized choice of m<<N test functions. This yields an underdetermined m x N linear system, that is solved by means of sparse optimization techniques. A theoretical analysis of the CORSING procedure is presented, based on the concepts of local a-coherence and restricted inf-sup property, along with numerical experiments that confirm the robustness and reliability of the proposed strategy. === Everyone is welcome! -- --federico poloni

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Mathematica
by Francesco Romani 29 Feb '16

29 Feb '16

Anche quest’anno, all’interno del corso di Esperienze di Programmazione, faccio 4-5 seminari su Mathematica. L’orario è mercoledi 11-13 / Venerdi 16-18 Avendo una certra libertà per collocarli volevo sapere se qualcuno ha intenzione di seguirli e ha preferenze sugli orari. Grazie saluti Francesco ____________________________ Prof. Francesco Romani Dipartimento di Informatica Via Buonarroti 2, 56127 PISA, ITALY Tel +39-050-2212734 FAX +39-050-2212726 http://www.di.unipi.it/~romani

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Optimization & Numerical Analysis seminars: Masciotta
by Federico Poloni 29 Feb '16

29 Feb '16

Speaker: Andrea Masciotta Affiliation: Dipartimento di Matematica, Università di Pisa Time: Monday, 7 March 2016, 14:30 Place: Sala Seminari Ovest, Dipartimento di Informatica, Università di Pisa Title: Minimization algorithms for compressive sensing Abstract: Compressive sensing is a new approach to digital signals acquisition and processing. Its main aim is the reconstruction of sparse signals or images (i.e. with few significant coefficients) from what was previously believed to be incomplete information. Compressive sensing has many potential applications, not only limited to the analysis of signals or images. In this talk we will first describe the main theoretical properties of compressive sensing, then three solution algorithms based on \ell_1 minimization will be presented, along with numerical experiments to highlight the main characteristics of these three methods in the framework of compressive sensing. === Everyone is welcome! -- --federico poloni Dipartimento di Informatica, Università di Pisa http://www.di.unipi.it/~fpoloni/ tel:+39-050-2213143

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Optimization & Numerical Analysis seminars: Miglierina
by Federico Poloni 17 Feb '16

17 Feb '16

Speaker: Enrico Miglierina Affiliation: Università Cattolica del Sacro Cuore, Milano Time: Thursday, 25 February 2016, 15:00 Place: Sala Seminari Est, Dipartimento di Informatica, Università di Pisa Title: Stability by set convergences: from Vector to Set optimization Abstract: (pdf) http://pages.di.unipi.it/fpoloni/files/seminari/Miglierina.pdf The notions of set convergences reveal to be very useful to study stability properties in vector optimization. Indeed, some results that show how the convergence of feasible region implies the convergence of efficient frontiers are known. The oldest ones are based on suitable compactness assumptions that concern the sequence of sets as a whole(see \cite{Attouch-Rihai,Bednarczuk2007,Luc-Lucchetti-Malivert,LoridanMorganRaucci,Penot-Sterna}). Moreover, more recently, some results about convergence of efficient frontiers have been obtained by replacing compactness by convexity (\cite{Lucchetti-Miglierina2004Opt,MM2005}). After a presentation of these results, the last aim of the talk is to extend this class of results to the broader framework of set optimization, that recently received an increasing attention in the literature (\cite{Gutierrez-Miglierina-Molho-Novo}). === Everyone is welcome! -- --federico poloni _______________________________________________ Numpi.di mailing list Numpi.di(a)listgateway.unipi.it http://listgateway.unipi.it/mailman/listinfo/numpi.di

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NumPI February 2016