Dipartimento di Matematica

Ricerca - Laboratori - Formazione

Direttore: Prof. Giulio Magli

Direttore Vicario: Prof. Gabriele Grillo

Responsabile Gestionale: Dr.ssa Franca Di Censo

more... ICIAM Lagrange Prize 2023 awarded to Alfio Quarteroni

MOX

Laboratorio di Modellistica
e
Calcolo Scientifico

EFFEDIESSE

Laboratorio di Formazione
e
Sperimentazione Didattica

analysis@polimi

Research Group

QFINLAB

Laboratorio di Finanza Quantitativa

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Prossimi Eventi

ott 10 lun 2022

MOX Seminar
Antonio Cicone, Mathematics for Signal Processing: new results and open challenges, 10-10-2022, ore 14:00
- MOX Seminar
- Antonio Cicone
- Department of Information Engineering, Computer Science and Mathematics, University of L'Aquila
- Mathematics for Signal Processing: new results and open challenges
- Lunedì 10 ottobre 2022 alle ore 14:00
- Aula Saleri - Dipartimento di Matematica
- Abstract
  
  In many applied fields of research, like Geophysics, Medicine, Engineering, Economy, and Finance, to mention a few, classical challenging problems are the identification of hidden information and features contained in a given signal, like quasi-periodicities and frequency patterns, as well as the extraction of all the different components contained in it.
  Standard methods based on Fourier and Wavelet Transform, historically used in Signal Processing, proved to be limited in the presence of nonlinear and non-stationary phenomena. For this reason, in the last two decades, several new nonlinear methods have been developed by many research groups around the world, and they have been used extensively in several applied fields of research.
  In this talk, we will briefly review the pioneering technique Hilbert-Huang Transform (a.k.a. Empirical Mode Decomposition method) and discuss its known limitations. Then, we will introduce the Iterative Filtering technique and its generalizations to handle multidimensional, multivariate, or highly non-stationary signals, as well as the newly developed time-frequency representation called IMFogram. We will discuss these methods theoretical and numerical properties and show their applications to real-life data.
  We will conclude the talk by reviewing the main limitations of these techniques and open challenges in this research field.
  Contatto: roberto.piersanti@polimi.it
- Politecnico di Milano, Dipartimento di Matematica edificio 14, via Giuseppe Ponzio 31/P, 20133 Milano - Telefono: +39 02 2399 4505 - Fax: +39 02 2399 4568

ott 14 ven 2022

MOX Colloquia
Anthony T. Patera, Perspectives on Engineering Estimation via the Heat Transfer Dunking Problem, 14-10-2022, ore 14:00

MOX Colloquia
Anthony T. Patera
Department of Mechanical Engineering, Massachusetts Institute of Technology
Perspectives on Engineering Estimation via the Heat Transfer Dunking Problem
Venerdì 14 ottobre 2022 alle ore 14:00
Online seminar: mox.polimi.it/mox-seminars/?id_evento=2185
Abstract

We consider the dunking problem: a solid body, initially at thermal equilibrium in a first environment at temperature Ti, is abruptly placed - “dunked” - at time t = 0 in a second environment, characterized by farfield fluid/enclosure temperature Too. The Quantities of Interest (QoI) describe the spatial distribution of the temperature as a function of time.
The high-fidelity mathematical model for the dunking problem - a very detailed conjugate heat transfer formulation - is not practical for typical engineering studies. However, the QoI can be predicted, inexpensively and reasonably accurately, by well-established engineering Estimation procedures: simplification of the high-fidelity mathematical model; subsequent approximate solution of the simplified mathematical model, often informed by archived experimental data.
In this talk we present error estimates for the engineering Estimation QoI predictions.
In fact, dunking is one example of a heat transfer problem class: a problem description for which the instances arise - in response to a particular ubiquitous need - very often in practice. Other heat transfer problem classes include wall and fin, each of which also admit Estimation procedures and associated error estimates. The collective scope of the problem classes in concert with the guidance provided by the error estimates can ultimately be incorporated in an autonomous heat transfer Estimation framework. We close with a preliminary demonstration of autonomous heat transfer Estimation: the software (a) accepts a non-prescriptive problem statement in the form of English text and an associated geometry figure, (b) identifies and instantiates the appropriate heat transfer problem class, (c) develops the simplified mathematical model and associated approximate solution, the latter incorporating asymptotic techniques as well as computational and experimental data, and (d) provides a summary of the Estimation QoI prediction and associated justifications.

Acknowledgements: work performed in collaboration with Kento Kaneko, MIT, Claude Le Bris, ENPC, Max Kessler, MIT (2020), and undergraduate students in MIT heat transfer subject 2.51; work funded by the Office of Naval Research, grant monitor Reza Malek-Madani.

Contatto: alfio.quarteroni@polimi.it

Anthony T. Patera

Anthony T. Patera is Professor of Mechanical Engineering and Ford Professor of Engineering at the Massachusetts Institute of Technology (MIT). Professor Patera received his SB and SM degrees in Mechanical Engineering and his PhD degree in Applied Mathematics, all from MIT. Professor Patera’s research interests include fluid dynamics and heat transfer, partial differential equations, variational techniques, computational methods, model reduction, and numerical analysis.

Politecnico di Milano, Dipartimento di Matematica edificio 14, via Giuseppe Ponzio 31/P, 20133 Milano - Telefono: +39 02 2399 4505 - Fax: +39 02 2399 4568

ott 17 lun 2022

MOX Seminar
Giulia Scalet, When shape memory polymers meet 4D printing: challenges, advances, and perspectives in material modeling and simulation, 17-10-2022, ore 15:30
- MOX Seminar
- Giulia Scalet
- Department of Civil Engineering and Architecture, University of Pavia
- When shape memory polymers meet 4D printing: challenges, advances, and perspectives in material modeling and simulation
- Lunedì 17 ottobre 2022 alle ore 15:30
- Aula Saleri - MOX - Dipartimento di Matematica
- Abstract
  
  In recent years, 4D printing has emerged as an innovative manufacturing approach that combines 3D printing and stimuli-responsive materials to produce objects with complex geometries and capable of transforming themselves over time (the 4th dimension) after being manufactured, under the application of an external stimulus.
  Particularly, the shape memory effect in polymers is a stimuli-responsive feature that is attracting more and more attention in 4D printing, thanks to its potential in producing innovative structures with customized architectures and programmable behavior. The latter is a highly demanded feature in several fields since it allows the structure to adapt to the application needs or to dynamic environmental variables.
  To bring this technology closer to application, material modeling, numerical simulations, and optimization approaches are of particular importance. However, they represent a fundamental, but challenging and currently under-developed topic due to the tight connection between process, nonlinear material behavior, and the final design.
  This talk will present our recent modeling, computational, and experimental efforts to achieve programmability in light- and thermo-responsive shape memory polymers manufactured via 4D printing. A special focus will be given to the macroscopic phenomenological modeling of the SME in polymers, combined with finite element analysis and density-based topology optimization. Recent application examples and future perspectives will be discussed, with a special focus on soft actuators, metamaterials, pharmaceutical devices, and tissue engineering.
  
  Contatto: pasquale.ciarletta@polimi.it
- Politecnico di Milano, Dipartimento di Matematica edificio 14, via Giuseppe Ponzio 31/P, 20133 Milano - Telefono: +39 02 2399 4505 - Fax: +39 02 2399 4568
ott 21 ven 2022

MOX Seminar
Alberto Lovison, Earthquakes, lab-quakes, and a seismology perspective on bursty human dynamics, 21-10-2022, ore 10:15
- MOX Seminar
- Alberto Lovison
- Dipartimento di Matematica, Politecnico di Milano
- Earthquakes, lab-quakes, and a seismology perspective on bursty human dynamics
- Venerdì 21 ottobre 2022 alle ore 10:15
- Aula Saleri - MOX - Dipartimento di Matematica
- Abstract
  
  It has been shown in recent years that there are deep analogies between some well-known
  statistical properties of earthquakes (km-scale phenomena), such as the Gutenberg-Richter, the
  Omori, and the productivity laws, and the avalanche statistics observed in fracture and plasticity in
  materials science (”lab-quakes”, mm- and micron- scale phenomena). Similar statistical regularities
  have also been observed in the bursty behavior of financial markets. I will report on current work
  which extends this perspective also to the analysis of bursty human dynamics, specifically of long-
  term written communication (email) data. In these, we observe scaling regularities strikingly similar
  to the above-mentioned ones in earthquakes and lab-quakes, a possible indication of universal
  features exhibited by the dynamics of complex systems heterogeneous in space and time.
  
  Contatto: anna.scotti@polimi.it
- Politecnico di Milano, Dipartimento di Matematica edificio 14, via Giuseppe Ponzio 31/P, 20133 Milano - Telefono: +39 02 2399 4505 - Fax: +39 02 2399 4568
ott 24 lun 2022

Seminar
Maryna Viazovska (Fields Medal 2022), TBA, 24-10-2022, ore 17:30
- Seminar
- Maryna Viazovska (Fields Medal 2022)
- EPFL, Lausanne
- TBA
- Lunedì 24 ottobre 2022 alle ore 17:30
- Aula Rogers
- Abstract
  
  Abstract will follow. To participate in presence, please register using the link
  
  forms.office.com/r/8HQCMBnec5
- Politecnico di Milano, Dipartimento di Matematica edificio 14, via Giuseppe Ponzio 31/P, 20133 Milano - Telefono: +39 02 2399 4505 - Fax: +39 02 2399 4568
nov 28 lun 2022

MOX Seminar
Ana Budisa, Solvers for Multiphysics Problems in Brain Biomechanics, 28-11-2022, ore 10:00
- MOX Seminar
- Ana Budisa
- Simula Research Laboratory, Oslo, Norway
- Solvers for Multiphysics Problems in Brain Biomechanics
- Lunedì 28 novembre 2022 alle ore 10:00
- Aula Saleri - MOX - Dipartimento di Matematica
- Abstract
  
  We are interested in reliable simulations of some biophysical processes in the brain, such as blood flow and metabolic waste clearance. Modeling those processes results in interface-driven multiphysics problems that can be coupled across dimensions. However, the complexity of the interface coupling often deteriorates the performance of standard methods to finding the numerical solution. Therefore, we derive preconditioners and solution techniques which target specifically such multiphysics problems for order
  optimal solving performance.
  The coupling that enforces constraints on the interface can primarily be imposed in two ways – with or without a Lagrange multiplier. In the former, the well-posedness of the system of equations is given in fractional Sobolev spaces weighted by material parameters. Therefore, the robust preconditioners for the interface problems are represented as a sum of fractional Laplacians that can include both negative and positive fractionalities. To handle fractional operators numerically, we implement methods based on the
  rational approximation. For the systems without a Lagrange multiplier, we focus on solvers based on algebraic multigrid method with custom smoothers that preserve the coupling information on each coarse level. We prove that, for the two-level setting, we obtain convergence that is independent of the
  mesh and material parameters.
  In both approaches, we show parameter-independence and scalability with regards to number of the degrees of freedom of the system. This is demonstrated on several numerical examples on realistic geometries, such as the viscous-porous flow coupling of the cerebrospinal fluid or the mixeddimensional
  model of flow in vascularized brain tissue.
  
  Contatto: paola.antonietti@polimi.it
- Politecnico di Milano, Dipartimento di Matematica edificio 14, via Giuseppe Ponzio 31/P, 20133 Milano - Telefono: +39 02 2399 4505 - Fax: +39 02 2399 4568