### Seminari

### Prossimi Seminari

**Dealing with unreliable computing platforms at extreme scale**

Luc Giraud, INRIA (Inria Bordeaux – Sud-Ouest)

mercoledì 23 gennaio 2019 alle ore 14:00, Aula Consiglio VII Piano – Edificio 14, Dipartimento di Matematica POLITECNICO DI MILANO**Poroelasticity: Discretizations and fast solvers based on geometric multigrid methods**

Francisco José Gaspar Lorenz, Department of Applied Mathematics -Zaragoza University – Spain

giovedì 31 gennaio 2019 alle ore 14:00, Sala Consiglio VII Piano – Edificio 14, Dipartimento di Matematica POLITECNICO DI MILANO**Application of Polyconvexity and multivariable convexity of energy potentials in nonlinear solid mechanics**

Javier Bonet, University of Greenwich

giovedì 14 febbraio 2019 alle ore 14:00, Aula Consiglio VII Piano – Edificio 14, Dipartimento di Matematica POLITECNICO DI MILANO

### Seminari Passati

**Linear and nonlinear equations for beams and degenerate plates with double piers**

Maurizio Garrione, Politecnico di Milano

martedì 19 giugno 2018 alle ore 15:45, Aula seminari 6° pianoABSTRACTMotivated by the phenomena observed on the occasion of the famous Tacoma Narrows Bridge collapse in 1940, we deal with some nonlinear fourth-order differential equations related to the analysis of the dynamics of suspension bridges. Following a “structural” approach, we discuss the role of the position of intermediate piers in the stability of a hinged beam, making a comparison between different notions of stability. The analysis is carried out analytically, with some help from numerics. (Joint work with Filippo Gazzola)**Joint and Individual Variation Explained**

Steve Marron, Department of Statistics and O.R., University of North Carolina

lunedì 18 giugno 2018 alle ore 14:00, Aula Consiglio VII Piano – Edificio 14, Dipartimento di Matematica POLITECNICO DI MILANOABSTRACTA major challenge in the age of Big Data is the integration of disparate data types into a data analysis. That is tackled here in the context of data blocks measured on a common set of experimental subjects. This data structure motivates the simultaneous exploration of the joint and individual variation within each data block. This is done here in a way that scales well to large data sets (with blocks of wildly disparate size), using principal angle analysis, careful formulation of the underlying linear algebra, and differing outputs depending on the analytical goals. Ideas are illustrated using mortality, cancer and neuroimaging data sets.

Contact: piercesare.secchi@polimi.it**Learning the Optimal Risk – Advanced Risk-Based Portfolio Management with Global Optimization Algorithms**

Marco Scaringi, Intesa Sanpaolo

martedì 12 giugno 2018 alle ore 13:45 precise, Aula Seminari Terzo Piano**Bialynicki-Birula decompositions and the Hilbert scheme of points**

Joachim Jelisiejew, Institute of Mathematics, Polish Academy of Sciences

venerdì 8 giugno 2018 alle ore 14:30 precise, Aula seminari del terzo pianoABSTRACTIn the talk I will briefly describe how a group action can be used to analyse a moduli space (or more generally, a functor) via a generalization of the Bialynicki-Birula decomposition. As a half-of-the-talk-example I will explain

what can be said for the Hilbert scheme of points on A^n (n>2) and in particular how to exhibit its components. In the last part I’ll carefully

review open questions: on the one hand, the newly exhibited smooth components are open to direct or experimental investigation and on the other hand, the new methods may help to answer classical open questions about those Hilbert schemes.**Biomechanical modeling of the heart, and cardiovascular system – From sarcomeres to organ / system, with experimental assessments and patient-specific clinical validations**

Dominique Chapelle, M3DISIM, INRIA – Paris – France

giovedì 7 giugno 2018 alle ore 10:30, Aula Consiglio VII Piano – Edificio 14, Dipartimento di Matematica POLITECNICO DI MILANOABSTRACTCardiac contraction originates at a subcellular – molecular, indeed – scale, within specific components of the cardiomyocytes (i.e. cardiac cells) called sarcomeres. This contractile behaviour then needs to be integrated at the organ level, namely, with a specific structure and shape. Furthermore, this organ crucially interacts with other physiological systems, the first of which being blood circulation via the cardiac function itself, and also the nervous system that controls the heart via various regulation mechanisms, and these interactions must be adequately represented in order to obtain accurate and predictive model simulations. This presentation will provide an overview of the recent advances on cardiac modeling achieved in the M3DISIM group, with a particular focus on the key multiscale, multi-physics and integrated system modeling aspects that need to be addressed, with many associated challenges pertaining to numerical methods and model validation, in particular.

Contact: alfio.quarteroni@polimi.it

**Inverse Problems for the Cardiac System**

Philippe Moireau, M3DISIM, INRIA – Paris – France

giovedì 7 giugno 2018 alle ore 14:00, Aula Consiglio VII Piano – Edificio 14, Dipartimento di Matematica POLITECNICO DI MILANOABSTRACTWhen considering the modeling of the cardiovascular system and more specifically the heart, there is a need for the personalization of not only the geometry but various aspects of the physical model: uncertain initial conditions, constitutive parameters or boundary conditions. Indeed, identifying key parameters – using measurements of a type that is available in medical imaging – can provide patient specific simulations that can be used by clinicians in their diagnosis. In other engineering fields where large amounts of data are available – like weather forecasting or climatology – it is now common to tackle these uncertainties in the models by data assimilation procedures – variational (4D-var) or sequential (Kalman like). In this context, our objective is to propose and analyze data assimilation methods adapted to the specificity of the biomechanical systems considered and to the available data, in particular image sequences.

Contact: alfio.quarteroni@polimi.it

**Missione Planck, l’immagine dell’universo neonato**

Marco Bersanelli, Università degli Studi di Milano

mercoledì 6 giugno 2018 alle ore 12:15, Politecnico di Milano Campus Bonardi Edificio14 aula B21**The essential norm estimates of Hankel and the $\overline\partial$-Neumann operators**

Zeljko Cuckovic, University of Toledo

venerdì 1 giugno 2018 alle ore 11:00, Sala di Rappresentanza, Università di Milano, Via C. Saldini 50, MilanoABSTRACTCompactness of the $\overline\partial$-Neumann operator is

closely connected to the compactness of Hankel operators on the Bergman

space. At first, for convex domains in $\mathbb{C}^n$, we use the

$\overline\partial$ methods to relate the compactness of a Hankel

operator to the boundary behavior of its symbol. In the absence of

compactness, we give the essential norm estimates of Hankel operators.

This in turn, led us to obtain the essential norm estimates for the

$\overline\partial$-Neumann operator on convex domains. (This is joint

work with Sonmez Sahutoglu)