Department of Mathematics and Systems Analysis

Current

Lectures, seminars and dissertations

* Dates within the next 7 days are marked by a star.

Jaakko Pere
On estimation of extreme probability contours under multivariate elliptical Fréchet distributions (Master's thesis presentation)
* Wednesday 03 March 2021,   09:00,   https://aalto.zoom.us/j/9150514867

Emilia Blåsten (Aalto University)
Inverse spectral problem on discrete graphs
* Thursday 04 March 2021,   13:15,   https://aalto.zoom.us/j/67710120716
I will introduce the results of my latest publication, arXiv:2101.10026, and its background. The inverse spectral problem in partial differential equation asks for determining unknown coefficients of given partial differential equation, or the underlying manifold structure, from boundary spectral measurements. These are the pairs of all eigenvalues with the boundary normal derivatives of their corresponding Dirichlet eigenfunctions to a fixed partial differential operator. The eigenvalues themselves are not enough to determine the underlying geometry: one cannot hear the shape of a drum. The question has been studied extensively for quantum graphs, but with limited success except for trees. My latest publication takes this topic into the context of discrete graphs. Given a subset of vertices (call it the boundary), and boundary values of Neumann eigenvectors to a graph Laplacian, we show that the rest of the graph structure can be determined assuming that there is "enough" boundary vertices.

Past events

Maija Vahteristo
On the effects of cervical cancer screening (Master's thesis presentation)
Friday 19 February 2021,   10:00,   https://us04web.zoom.us/j/75952975071?pwd=YVJSL3lhS2U4ck1GaWlJMEF1Y0xJZz09
Passcode:0yF0Vh

María Quintana Ponce, Aalto University
Linearizations of Rational Matrices
Thursday 18 February 2021,   13:15,   https://aalto.zoom.us/j/67710120716
Zoom-link : https://aalto.zoom.us/j/67710120716 The numerical solution of rational eigenvalue problems (REPs) is getting a lot of attention. REPs appear directly from applications or they can be used for solving arbitrary nonlinear eigenvalue problems (NLEPs) by approximating the corresponding NLEP by a REP and, then, solving the REP. They also play a fundamental role in system and control theory. Nowadays, one of the most competitive methods for solving REPs is based on linearizations of the corresponding rational matrix. In this talk, we introduce a new notion of linearization for rational matrices, and we provide very simple criteria to determine when a linear polynomial matrix is one of these linearizations. As an application, we study the structure of linearizations constructed in the literature for rational approximations of NLEPs.

Leevi Lindgren
On Moment-Based Estimation of Extreme Probability Contours Under Ellipticity (Master's thesis presentation)
Wednesday 10 February 2021,   10:00,   in Teams
https://teams.microsoft.com/l/meetup-join/19%3ameeting_OGI4YTk3YjktOGVkOC00MzBiLThlZmUtMmQzY2U5NTU3NWUz%40thread.v2/0?context=%7b%22Tid%22%3a%22af2afc02-96d2-4cff-b1b5-d43897ff97ad%22%2c%22Oid%22%3a%22e36756e7-9e4d-48ef-bad1-d1a1e6d333ec%22%7d

Tuomas Tuukkanen
Haar measures on locally compact groups (harmonic analysis workshop)
Friday 05 February 2021,   10:15,   https://aalto.zoom.us/j/67515140063
Seminar on analysis and geometry

Timo Takala
The duality of Hardy functions and BMO functions (harmonic analysis workshop)
Friday 29 January 2021,   10:15,   https://aalto.zoom.us/j/61457600970
Seminar on analysis and geometry

Laura Jakobsson
A survey of the Miyata-Proudfoot-Ramos category of graphs, 2
Friday 15 January 2021,   11:00,   https://aalto.zoom.us/j/62497682030
https://aalto.zoom.us/j/62497682030
Alexander Engström

Christoffer Lundström
Primtalssatsen
Monday 21 December 2020,   14:15,   https://aalto.zoom.us/j/68077881815
BSc thesis presentation. The presentation will be in Swedish.

Laura Jakobsson
A survey of the Miyata-Proudfoot-Ramos category of graphs, 1
Friday 18 December 2020,   11:00,   https://aalto.zoom.us/j/65122897296
https://aalto.zoom.us/j/65122897296
Engström

Kim Myyryläinen
Rubio de Francia extrapolation theorem (harmonic analysis workshop)
Wednesday 16 December 2020,   10:15,   https://aalto.zoom.us/j/63006317735
Seminar on analysis and geometry

Napoleon Freitas Paajanen
Connection between Littlewood-Paley operators and Calderón-Zygmund integral kernels (harmonic analysis workshop)
Tuesday 15 December 2020,   14:15,   https://aalto.zoom.us/j/69928590389
Seminar on analysis and geometry

Niklas Miller
Algebraic number theory: an analysis of well-rounded lattices (MSc thesis presentation)
Tuesday 15 December 2020,   14:00,   https://aalto.zoom.us/j/68470667079
ANTA

Lari-Matti Tuomala
Secure coded multi-party matrix multiplication (MSc thesis presentation)
Tuesday 15 December 2020,   13:00,   https://aalto.zoom.us/j/68470667079
ANTA

Lauri Särkiö
Boundedness of convolution type Calderón-Zygmund operators (harmonic analysis workshop)
Tuesday 15 December 2020,   10:15,   https://aalto.zoom.us/j/69928590389
Seminar on analysis and geometry

Kristian Moring
Supercaloric functions to the singular parabolic p-Laplace equation in the supercritical case
Monday 14 December 2020,   14:15,   https://aalto.zoom.us/j/64913244648
Seminar on analysis and geometry

Napoleon Freitas Paajanen
Sobolev characterization based on Marcinkiewicz integral transform (diploma thesis presentation)
Monday 14 December 2020,   10:15,   https://aalto.zoom.us/j/64913244648
Seminar on analysis and geometry

Pasi Hakulinen
On the Backward Monte-Carlo Method with Application to Fast Ion Simulation in Magnetized Plasma
Friday 11 December 2020,   14:15,   https://aalto.zoom.us/j/2126347484
https://aalto.zoom.us/j/2126347484

Dissertation
Henri Södergård (Aalto University)
Image deblurring by numerical linear algebra (BSc thesis)
Wednesday 09 December 2020,   14:15,   https://aalto.zoom.us/j/67899163157
When taking a photograph, we usually want the resulting image to be a faithful reconstruction of the reality we see with our own eyes. However, almost all images will inevitably suffer from some form of imperfections such as blurriness. To fix this, we can deblur the image employing methods and techniques from numerical linear algebra to mathematically. This way, we can restore the maximum amount of information about the true image from a blurry image. In this talk, I plan to introduce some basic concepts in image deblurring, including the naive solution, the point spread function, spectral filtering (such as Truncated Singular Value Decomposition or the Tikhonov method) and regularisation methods (such as Generalised Cross Validation, the Discrepancy Principle and the L-Curve Criterion). I will also present the results of some experiments that I have run to compare some of these methods in practice, by testing them on some blurred images.
BSc Seminar

Lauri Hitruhin
Boundary behaviour of conformal and quasiconformal mappings
Monday 07 December 2020,   14:15,   https://aalto.zoom.us/j/68924190377
Seminar on analysis and geometry

Cintia Pacchiano
Regularity properties for quasi-minimizers of a (p,q)-Dirichlet integral
Monday 07 December 2020,   10:15,   https://aalto.zoom.us/j/68924190377
Seminar on analysis and geometry

Dr Jeta Molla (Aalto University)
Numerical methods for the stochastic wave equation
Tuesday 24 November 2020,   16:00,   https://aalto.zoom.us/j/68911259210
Further information
The objective of this talk is to propose a full discretization for the stochastic wave equation. More specifically, the discontinuous Galerkin finite element method is used in space and analyzed in a semigroup framework, and an explicit stochastic position Verlet scheme is used for the temporal approximation. Numerical experiments illustrate our theoretical results on strong convergence rates. Further, we analyze and bound the expected energy and numerically show excellent agreement with the energy of the exact solution. Join Zoom Meeting https://aalto.zoom.us/j/68911259210 Meeting ID: 689 1125 9210
Aalto Stochastics & Statistics Seminar / Leskelä

Emma-Karoliina Kurki
Integral estimates on Whitney chains
Monday 09 November 2020,   14:15,   M237
Seminar on analysis and geometry

Kim Myyryläinen
Median-type John–Nirenberg spaces
Monday 09 November 2020,   10:15,   M237
Seminar on analysis and geometry

Dissertation
Mohamed Taoufiq Damir
Well-rounded lattices and applications to physical layer security (Doctoral defence)
Friday 06 November 2020,   15:00,   Zoom https://aalto.zoom.us/j/65632983027
Further information
ANTA

Julian Weigt
The dyadic maximal function has bounded variation
Monday 02 November 2020,   14:15,   M237
Seminar on analysis and geometry

Carlos Mudarra
Extensions of jets with smooth convex functions and applications
Monday 02 November 2020,   10:15,   M237
Seminar on analysis and geometry

Prashanta Garain
Nonexistence of variational minimizers related to a quasilinear singular problem in metric measure spaces
Monday 05 October 2020,   14:15,   M237
Seminar on analysis and geometry

Sauli Lindberg
Convex integration in magnetohydrodynamics
Monday 05 October 2020,   10:15,   M237
Seminar on analysis and geometry

Afrin Hossain
Fatou and Julia sets in Rational Iteration (kandiesitelmä)
Monday 21 September 2020,   13:15,   M237

Oona Oinonen
Dihedraalisen piilotetun aliryhmän ongelma (kandiesitelmä)
Monday 21 September 2020,   11:00,   Zoom https://aalto.zoom.us/j/63992296777
ANTA

Antti Immonen
Secure Distributed Matrix Multiplication (BSc presentation)
Monday 21 September 2020,   10:15,   Zoom https://aalto.zoom.us/j/63992296777
ANTA

Kalle Kytölä
Euler integrals and a quantum group
Monday 31 August 2020,   15:45,   https://aalto.zoom.us/j/62494927603
mathematical physics end-of-summer seminar day (Kytölä)

Shinji Koshida
Point processes and fermionic algebras
Monday 31 August 2020,   15:00,   https://aalto.zoom.us/j/62494927603
mathematical physics end-of-summer seminar day (Kytölä)

Eveliina Peltola
On large deviations of multiple SLEs
Monday 31 August 2020,   14:15,   https://aalto.zoom.us/j/62494927603
mathematical physics end-of-summer seminar day (Kytölä)

Aapo Pajala
Euclidean Distance Geometry and Its Applications in 3D Genome Reconstruction (Bachelor thesis presentation)
Monday 31 August 2020,   14:00,   https://aalto.zoom.us/j/69001841503

Konstantin Izyurov
Asymptotics of determinants of discrete Laplacians
Monday 31 August 2020,   13:30,   https://aalto.zoom.us/j/62494927603
mathematical physics end-of-summer seminar day (Kytölä)

Tuomas Tuukkanen
Probabilistic Liouville conformal field theory
Monday 31 August 2020,   11:45,   https://aalto.zoom.us/j/62494927603
mathematical physics end-of-summer seminar day (Kytölä)

Osama Abuzaid
TBA
Monday 31 August 2020,   11:00,   https://aalto.zoom.us/j/62494927603
mathematical physics end-of-summer seminar day (Kytölä)

Nerissa Shakespeare
Äärellisistä heijastusryhmistä (kandiesitelmä)
Monday 31 August 2020,   10:00,   https://aalto.zoom.us/j/64382365198
matematiikan kandiseminaari

Perttu Saarela
Hansen polytopes of split graphs (Bachelor thesis presentation)
Friday 28 August 2020,   11:30,   U5 (U147)
https://aalto.zoom.us/j/61788754640

Kai Hippi
Tutte-polynomien laskeminen (Kandiesitelmä)
Friday 28 August 2020,   10:45,   U5 (U147)
https://aalto.zoom.us/j/61788754640

Meri Aho
Cyclic flats and graphical matroids (Bachelor thesis presentation)
Friday 28 August 2020,   10:00,   U5 (U147)
https://aalto.zoom.us/j/61788754640

Selim Virtanen
Johdatus p-adisiin lukuihin ja lokaali-globaali-periaatteeseen (kandiesitelmä)
Thursday 27 August 2020,   14:00,   U5 and Zoom https://aalto.zoom.us/j/64748623259
ANTA

Okko Makkonen
Tuplaavuus ja Sobolevin upotus (Kandityöesitelmä)
Thursday 27 August 2020,   13:15,   U5
Kandiseminaari

Joonas Laaksonen
Legendren sarjakehitelmän suppenemisesta 2D:ssä (Kandiesitelmä)
Thursday 27 August 2020,   11:00,   https://aalto.zoom.us/j/67335018504
Kandiesitelmä

Etna Lindy
Parameter estimation for group-based phylogenetic models in the probability and Fourier coordinates (Bachelor thesis presentation)
Wednesday 26 August 2020,   11:00,   zoom
https://aalto.zoom.us/j/69001841503

Aleksi Lahti
Classifying critical points of the Euclidean Distance from real plane curves (Bachelor thesis presentation)
Wednesday 26 August 2020,   10:00,   zoom
https://aalto.zoom.us/j/69001841503

Dr Mikhail Shubin (THL)
Fitting SEIR models to COVID wave in Finland: Lessons and open questions
Thursday 25 June 2020,   15:00,   Teams
Further information
The seminar is intended for epidemiological modellers. I will present a set SEIR models used by THL to model the COVID outbreak in Finland. I will analyse particular model features, discussing whatever they there useful for inference. I will describe different questions which we tried to answer with these models, and wherever modelling was able to provide useful insight. For any questions, contact Mikhail (Mikhail.shubin@thl.fi https://teams.microsoft.com/l/meetup-join/19%3ameeting_NjE4MDVkYWUtOGQ5MS00YWIxLWIwNDYtMzUxZjQyNmExOTE5%40thread.v2/0?context=%7b%22Tid%22%3a%2281d1db0d-c492-4225-a66c-3c3a9e4b8360%22%2c%22Oid%22%3a%221373e033-bd9e-4fa9-898a-a07b58e1f61e%22%7d
Aalto Stochastics & Statistics Seminar / Leskelä

Alex Karrila (IHÉS, Paris)
Delocalization of the six-vertex height function
Thursday 11 June 2020,   10:15,   https://aalto.zoom.us/j/66281157229
The six-vertex model is a planar random model for the crystalline structure of water ice. It has recently given important insights to the connection of Conformal field theory and critical 2D random models, due to its natural representation as a random field, called the height function, and due to couplings to several other important random models (e.g. FK cluster model, Ising and Potts models, dimers, random graph homomorphisms) We prove that the six-vertex height function has a localization/delocalization phase transition. Delocalization means roughly speaking that the model is not sensitive to a boundary condition far away; indeed our result for instance implies that there exists a unique whole-plane six-vertex model in the delocalized phase. The main tools of the proof are an explicit solution of the free energy of the model, and RSW and FKG inequalities similar as in the study of various percolation models. (Based on ongoing work with Hugo Duminil-Copin, Ioan Manolescu, and Mendes Oulamara.) Zoom-link: https://aalto.zoom.us/j/66281157229
Kytölä

Dissertation
Ferdinand Blomqvist
PhD defense: On Decoding Problems, Lattices and Generalized Concatenated Codes
Wednesday 22 April 2020,   16:00,   Zoom
Further information
Link for joining the online defense: https://aalto.zoom.us/j/651995701
ANTA

Lauri Hitruhin
Convex integration and incompressible porous media equation
Wednesday 11 March 2020,   12:15,   M3 (M234)
Seminar on analysis and geometry

Chris Brzuska
Reading circle on lattices and lattice-based cryptography: on public key crypto and complexity
Wednesday 11 March 2020,   10:15,   M3 (M234)
The reading circle will gather around 10 times, check the ANTA seminar page for detailed times and talk titles.
ANTA

Dr. Hossein Mostafaei (Aalto)
Discrete- and Continuous-time Scheduling Formulations for Industrial Processes
Monday 09 March 2020,   15:15,   Y225a (Riihi)
SAL Monday seminar

Prof. Shmuel S. Oren, University of California at Berkeley
Challenges and Opportunities for OR in Electricity Markets
Friday 06 March 2020,   14:00,   M1 (M232)
Further information

Carlos Mudarra
Bounded extension operators for jets of class C^{1,w} in Hilbert spaces
Wednesday 04 March 2020,   12:15,   M3 (M234)
Seminar on analysis and geometry

Taoufiq Damir
Reading circle on lattices and lattice-based cryptography: hardness of lattice problems
Wednesday 04 March 2020,   10:15,   M3 (M234)
The reading circle will gather around 10 times, check the ANTA seminar page for detailed times and talk titles.
ANTA

Konstantin Avrachenkov (INRIA Sophia Antipolis)
Hedonic coalitional game approach to network partitioning
Monday 02 March 2020,   15:15,   M205
The traditional methods for detecting community structure in a network are based on selecting dense subgraphs inside the network. Here we propose to use the methods of coalitional game theory that highlight not only the link density but also the mechanisms of cluster formation. Specifically, we propose an approach which is based on hedonic coalitional games. This approach allows to find clusters with various resolution. Furthermore, the modularity-based approach and its generalizations as well as ratio cut and normalized cut methods can be viewed as particular cases of the hedonic games. Finally, for methods based on potential hedonic games we suggest a very efficient computational scheme using Gibbs sampling. Bio: Konstantin Avrachenkov received the master’s degree in control theory from St. Petersburg State Polytechnic University in 1996, the Ph.D. degree in mathematics from the University of South Australia in 2000, and the Habilitation (Doctor of Science) degree from the University of Nice Sophia Antipolis in 2010. Currently, K. Avrachenkov is Director of Research at Inria Sophia Antipolis. His main research interests are Markov chains, Markov decision processes, stochastic games and singular perturbations. He applies these methodological tools to the modelling and control of telecommunication systems and to design data mining and machine learning algorithms. He has won 5 best paper awards. He is an Associate Editor of the International Journal of Performance Evaluation, Probability in the Engineering and InformationalSciences, ACM TOMPECS and Stochastic Models.
Aalto Stochastics & Statistics Seminar

M.Sc. Juho Roponen (Aalto)
Protecting ship resupplying from UAV reconnaissance
Monday 02 March 2020,   15:15,   Y225a (Riihi)
SAL Monday seminar

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