Händelser: Matematiska vetenskaperhttp://www.chalmers.se/sv/om-chalmers/kalendariumAktuella händelser på Chalmers tekniska högskolaMon, 18 Oct 2021 16:04:00 +0200http://www.chalmers.se/sv/om-chalmers/kalendariumhttps://www.chalmers.se/sv/institutioner/math/kalendarium/Sidor/Analysis-and-Probability211019.aspxhttps://www.chalmers.se/sv/institutioner/math/kalendarium/Sidor/Analysis-and-Probability211019.aspxAnalysis and Probability seminar<p>Online</p><p>​Eveliina Peltola, Bonn and Aalto: On Loewner evolutions with jumps</p><p>​<br />I discuss the behavior of Loewner evolutions driven by a Levy process. Schramm's celebrated version (Schramm-Loewner evolution), driven by standard Brownian motion, has been a great success for describing critical interfaces in statistical physics. Loewner evolutions with other random drivers have been proposed, for instance, as candidates for finding extremal multifractal spectra, and some tree-like growth processes in statistical physics. Questions on how the Loewner trace behaves, e.g., whether it is generated by a (discontinuous) curve, whether it is locally connected, tree-like, or forest-like, have been partially answered in the symmetric alpha-stable case. We consider the case of general Levy drivers.</p> <p>This talk is based on joint work with Anne Schreuder (Cambridge).</p> <p>The seminar will be held via zoom. Members of the department will receive the link and password via mail. Others interested are welcome to attend and can get the link by contacting one of the organisers (please inform us who you are).</p>https://www.chalmers.se/sv/institutioner/math/kalendarium/Sidor/Statistics211019.aspxhttps://www.chalmers.se/sv/institutioner/math/kalendarium/Sidor/Statistics211019.aspxStatistics seminar<p>online</p><p>​Alice Corbella, Warwick University: Introducing Zig-Zag Sampling and making it applicable</p><p>​<br />Abstract: Recent research showed that Piecewise Deterministic Markov Processes (PDMP) may be exploited to design efficient MCMC algorithms [1]. The Zig-Zag sampler is an example of this: it is based on the simulation of a PDMP whose switching rate λ(t) is governed by the derivative of a (minus log) target density. </p> <p>While many theoretical properties of this sampler have been derived, less has been done to explore the applicability of the Zig-Zag sampler to solve Bayesian inference problems. In particular, the computation of the derivative of the log-density in the rate λ(t) might be challenging. To expand the applicability of the Zig-Zag sampler, we incorporate Automatic Differentiation tools in the Zig-Zag algorithm, to evaluate λ(t) from the functional form of the log-target density. Moreover, to allow the simulation of a PDMP via Poisson thinning, we use univariate optimization routines to find local upper bounds. </p> <p>In this talk we introduce PDMPs and the Zig-Zag sampler; we expose our Automatic Zig-Zag sampler; we discuss the challenges that arise with the simulation via thinning and the need of a new tuning parameter; and we comment on efficiencies and bottlenecks of AD for Zig-Zag. We present many examples to compare our method to HMC, another widely used gradient-based method.</p> <p>This is joint work with Simon Spencer and Gareth Roberts.</p> <p>[1] Fearnhead, P., Bierkens, J., Pollock, M., and Roberts, G.O., 2018. Piecewise deterministic Markov processes for continuous-time Monte Carlo. Statistical Science, 33(3), pp.386-412. </p>https://www.chalmers.se/sv/institutioner/math/kalendarium/Sidor/TLM-seminarium211020.aspxhttps://www.chalmers.se/sv/institutioner/math/kalendarium/Sidor/TLM-seminarium211020.aspxTLM-seminarium<p>MV:L14 och online</p><p>​Mikael Cronhjort och Yukiko Asami Johansson: Strukturerad problemlösning och kollegialt lärande för utveckling av lärares professionella kunskap</p>​<br />Abstract: Att överföra pedagogiska och didaktiska idéer från en kultur till en annan kan innebära både möjligheter och problem. Vi presenterar en analysmetod baserad på The anthropological theory of the didactic (ATD) för att studera hur lärare Sverige kan implementera idéer från den japanska undervisningsmetoden strukturerad problemlösning och för hur lärare kan bygga upp professionell kunskap.https://www.chalmers.se/sv/institutioner/math/kalendarium/Sidor/Computational211020.aspxhttps://www.chalmers.se/sv/institutioner/math/kalendarium/Sidor/Computational211020.aspxComputational and Applied Mathematics (CAM) seminar<p>MV:L14 och online</p><p>​Nick Higham, The University of Manchester: Random Orthogonal Matrices in Numerical Linear Algebra</p>​<br />Abstract: An important use of random orthogonal matrices is in forming random matrices with given singular values – so-called “randvsd” matrices. We explain how to speed up the usual approach to forming a randsvd matrix that employs random orthogonal matrices from the Haar distribution. We also explain the role that random orthogonal matrices play in a recently identified class of random, dense n × n matrices for which LU factorization with any form of pivoting produces a growth factor typically of size at least n/(4 log n) for large n.https://www.chalmers.se/sv/institutioner/math/kalendarium/Sidor/Algebraisk-geometri211020.aspxhttps://www.chalmers.se/sv/institutioner/math/kalendarium/Sidor/Algebraisk-geometri211020.aspxSeminariet i Algebraisk geometri och talteori<p>Online</p><p>​Caroline Turnage-Butterbaugh, Carleton College: Small gaps between zeros of the Riemann zeta-function</p><p>​<br />Abstract: Let g_1, g_2, ... denote the ordinates of the complex zeros of the Riemann zeta-function function in the upper half-plane in increasing order. The average distance between g_n and g_{n+1) is 2\pi / log g_n as n goes to infinity. An important goal is to prove unconditionally that these distances between consecutive zeros can be much, much smaller than the average for a positive proportion of zeros. We will discuss the motivation behind this endeavor, progress made assuming the Riemann Hypothesis, and recent work with A. Simonič and T. Trudgian to obtain an unconditional result that holds for a positive proportion of zeros. </p> <p>Zoom: <a href="https://chalmers.zoom.us/j/61940292699">https://chalmers.zoom.us/j/61940292699</a> </p>https://www.chalmers.se/sv/styrkeomraden/energi/kalendarium/Sidor/Vattenkraft--nya-utmaningar-i-ett-fornybart-energisystem.aspxhttps://www.chalmers.se/sv/styrkeomraden/energi/kalendarium/Sidor/Vattenkraft--nya-utmaningar-i-ett-fornybart-energisystem.aspxVattenkraft – nya utmaningar i ett förnybart energisystem<p>OOTO Café, café, Sven Hultins Plats 2, Johanneberg Science Park 2</p><p>​Nu är det dags för Chalmers styrkeområde Energis fjärde Fredagsseminarium &amp; afterwork.  Vi ses i kafé Ooto, Guldhuset, Johanneberg Science Park, 22 oktober, 15:30-17.00.På detta seminarium ger oss Håkan Nilsson ​och Mohammad Hossein Arabnejad olika perspektiv om vattenkraften som har en nyckelroll för att balansera elsystemet, både i form av effekt och frekvens, när övrig produktion och användning av elen varierar över tid. Så kom, lyssna, och träffa kollegor, Styrkeområdets ledning och diskutera nya forskningsidéer och nyheter inom området.</p>​<img src="/SiteCollectionImages/Institutioner/TM/Personal/håkannilsson.jpg" alt="Håkan Nilsson" class="chalmersPosition-FloatLeft" style="margin:5px;width:155px;height:155px" /><span style="background-color:initial"><b>Ursprungligen designad för baskraft</b> möter vattenkraften nya utmaningar som en viktig källa för reglerkraft i ett förnybart energisystem med intermittenta produktionsslag. <br /></span><div><ul><li><span style="background-color:initial">​Hur påverkas strömningen i turbinerna av det nya körsättet? </span></li> <li>Hur kör man säkert? </li> <li>Vad är kostnaden för denna reglerkraft? </li></ul> <div><a href="https://research.chalmers.se/person/hani">Håkan Nilsson​</a>, professor i strömningslära, ger en kort översikt över forskningsaktiviteter som ska bidra till svaret på dessa frågor.</div> <div><br /><img src="/SiteCollectionImages/Institutioner/M2/Personal/IMG_5825%20170.jpg" alt="Mohammad Hossein Arabnejad" class="chalmersPosition-FloatLeft" style="margin:5px;width:155px;height:155px" />Dr. <a href="/sv/personal/Sidor/Mohammad-Hossein-Arabnejad-Khanouki-.aspx">Mohammad Hossein Arabnejad</a>, post-doc i ett projekt finansierat av SO Energi, ger en fördjupning kring effekterna av kavitation.<br /></div> <div><b style="background-color:initial">Program:</b><br /></div> <div><ul><li>15:30, Välkommen Tomas Kåberger, Chalmers styrkeområde Energi.</li> <li>Håkan Nilsson, professor i strömningslära, och Dr. Mohammad Hossein Arabnejad. (Språk: engelska)</li> <li>Frågestund.</li> <li>16:00-17:00, Mingel.</li></ul></div> <div><br /></div> <div><span></span><span style="font-weight:700;background-color:initial">Målgruppen</span><span style="background-color:initial"> för seminariet är forskare och kollegor inom Chalmerssfären.​</span><br /></div> <div><br /></div> <span style="font-weight:700">Relaterat:<br /></span><a href="/sv/institutioner/m2/nyheter/Sidor/Energilagring-till-havs-ger-mer-tillförlitlig-sol--och-vindkraft.aspx">​</a><a href="/sv/styrkeomraden/energi/nyheter/Sidor/Vind--+-solenergi=-ny-utmaning-för-vattenkraften.aspx" style="background-color:rgb(255, 255, 255);outline:0px"><img class="ms-asset-icon ms-rtePosition-4" src="/_layouts/images/ichtm.gif" alt="" /></a><a href="/sv/institutioner/m2/nyheter/Sidor/Energilagring-till-havs-ger-mer-tillförlitlig-sol--och-vindkraft.aspx">Energilagring till havs ger mer tillförlitlig sol- och vindkraft​</a><br /><div><a href="/sv/styrkeomraden/energi/nyheter/Sidor/Vind--+-solenergi=-ny-utmaning-för-vattenkraften.aspx"><img class="ms-asset-icon ms-rtePosition-4" src="/_layouts/images/ichtm.gif" alt="" />Vind- + solenergi= ny utmaning för vattenkraften</a><div><span style="background-color:initial"><a href="https://www.tudelft.nl/en/eemcs/current/humans-of-eemcs/haakan-nilsson/"><img class="ms-asset-icon ms-rtePosition-4" src="/_layouts/images/icgen.gif" alt="" />Håkan Nilsson Visiting Professor TUDelft</a></span></div> <div><span style="background-color:initial"><a href="/sv/institutioner/m2/nyheter/Sidor/Från-vindsurfning-till-professorstjänst-.aspx"><img class="ms-asset-icon ms-rtePosition-4" src="/_layouts/images/ichtm.gif" alt="" />Den surfande professorn</a></span></div> <div><span style="background-color:initial"><a href="/sv/institutioner/m2/nyheter/Sidor/Från-vindsurfning-till-professorstjänst-.aspx"></a><a href="/sv/institutioner/m2/forskning/stromningslara/Sidor/default.aspx"><img class="ms-asset-icon ms-rtePosition-4" src="/_layouts/images/ichtm.gif" alt="" />Strömningslära på Chalmers</a></span></div></div></div> <div><br /></div> <div><b>Tidigare fredagsseminarier<br /></b><a href="/sv/styrkeomraden/energi/kalendarium/Sidor/Rapport-SWPTC-i-fokus.aspx"><img class="ms-asset-icon ms-rtePosition-4" src="/_layouts/images/ichtm.gif" alt="" />Vindkraften är en viktig pusselbit i framtidens elnät​</a><br /><h4 style="font-family:&quot;open sans&quot;, sans-serif;line-height:1.3;margin:0px;padding:0px 0px 5px"><a href="/sv/institutioner/m2/forskning/stromningslara/Sidor/default.aspx" style="font-family:&quot;open sans&quot;, sans-serif;font-size:14px;background-color:rgb(255, 255, 255);outline:0px"><img class="ms-asset-icon ms-rtePosition-4" src="/_layouts/images/ichtm.gif" alt="" />​</a><a class="titleLink clickLogger resultTitle" href="/sv/styrkeomraden/energi/kalendarium/Sidor/Plast-fran-avfall-till-attraktiv-ravara.aspx">Plast – från avfall till attraktiv råvara</a></h4></div> ​​​https://www.chalmers.se/sv/institutioner/math/kalendarium/Sidor/Pedagogiskt-seminarium211025.aspxhttps://www.chalmers.se/sv/institutioner/math/kalendarium/Sidor/Pedagogiskt-seminarium211025.aspxPedagogiskt seminarium<p>TBA</p><p>​Hossein Raufi: Erfarenheter av aktiv undervisning</p>​<br />Genom åren har jag experimenterat en del med olika sätt att få studenterna mer aktiva på lektioner. På seminariet tänkte jag berätta om några av dessa erfarenheter. Jag är också mycket intresserad av att höra från andra om deras erfarenheter och tankar kring aktiv undervisning.https://www.chalmers.se/sv/institutioner/math/kalendarium/Sidor/Computational211103.aspxhttps://www.chalmers.se/sv/institutioner/math/kalendarium/Sidor/Computational211103.aspxComputational and Applied Mathematics (CAM) seminar<p>MV:L14 och online</p><p>​Daniel Peterseim, Universität Augsburg: Energy-adaptive Riemannian Optimization on the Stiefel Manifold</p><p>​<br />Abstract: This talk addresses the numerical simulation of nonlinear eigenvector problems such as the Gross-Pitaevskii and Kohn-Sham equation arising in computational physics and chemistry. These problems characterize critical points of energy minimization problems on the infinite-dimensional Stiefel manifold. To efficiently compute minimizers we propose a novel Riemannian gradient descent method induced by an energy-adaptive metric. Quantified convergence of the method is established under suitable assumptions on the underlying problem. A non-monotone line search and the inexact inexact evaluation of Riemannian gradients substantially improve the overall efficiency of the method. Numerical experiments illustrate the performance of the method and demonstrates its competitiveness with well-established  schemes.</p> <p>This is joint work with Robert Altmann (U Augsburg) and Tatjana Stykel (U Augsburg).</p>https://www.chalmers.se/sv/institutioner/math/kalendarium/Sidor/Computational211104.aspxhttps://www.chalmers.se/sv/institutioner/math/kalendarium/Sidor/Computational211104.aspxComputational and Applied Mathematics (CAM) seminar<p>MV:L14 och online</p><p>​Stefan Horst Sommer, University of Copenhagen: Stochastic shape analysis and probabilistic geometric statistics</p>​<br />Abstract: Analysis and statistics of shape variation can be formulated in geometric settings with geodesics modelling transitions between shapes. The talk will concern extensions of these smooth geodesic models to account for noise and uncertainty: Stochastic shape processes and stochastic shape matching algorithms. In the stochastic setting, matching algorithms take the form of bridge simulation schemes which also provide approximations of the transition density of the stochastic shape processes. The talk will cover examples of stochastic shape processes and connected bridge simulation algorithms. I will connect these ideas to geometric statistics, the statistical analysis of general manifold valued data, particularly to the diffusion meanhttps://www.chalmers.se/sv/institutioner/math/kalendarium/Sidor/Pedagogiskt-seminarium211122.aspxhttps://www.chalmers.se/sv/institutioner/math/kalendarium/Sidor/Pedagogiskt-seminarium211122.aspxPedagogiskt seminarium<p>TBA</p><p>​TBA</p>https://www.chalmers.se/sv/institutioner/math/kalendarium/Sidor/Pedagogiskt-seminarium211220.aspxhttps://www.chalmers.se/sv/institutioner/math/kalendarium/Sidor/Pedagogiskt-seminarium211220.aspxPedagogiskt seminarium<p>TBA</p><p>​Johanna Pejlare: TBA</p>https://www.chalmers.se/sv/institutioner/math/kalendarium/Sidor/Noncommutativity-in-the-North-2021.aspxhttps://www.chalmers.se/sv/institutioner/math/kalendarium/Sidor/Noncommutativity-in-the-North-2021.aspxNoncommutativity in the North<p>Euler, Skeppsgränd 3</p><p>​New interactions between operator algebras and noncommutative geometry coming forth from recent developments in both areas</p><p></p> <p class="chalmersElement-P">​​The conference takes place March 14-18, 2022 at the department for Mathematical Sciences in <span>the University of Gothenburg and Chalmers University of Technology.</span></p> <div> </div> <p></p> <p>The conference aims at bringing together experts and younger mathematicians working on operator algebras and noncommutative geometry in particular from Scandinavia. The focus of the conference is on fostering new interactions between operator algebras and noncommutative geometry coming forth from recent developments in both areas. <br /><br /><strong>Speakers:</strong></p> <ul><li>James Gabe (University of Southern Denmark) </li> <li>Jens Kaad (University of Southern Denmark) </li> <li>Matthew Kennedy (University of Waterloo)</li> <li>David Kyed (University of Southern Denmark) </li> <li>Franz Luef (NTNU, Trondheim)</li> <li>Mikael Rørdam (University of Copenhagen)</li> <li>Tatiana Shulman (IMPAN, Warzaw)</li> <li>Adam Skalski (IMPAN, Warzaw)</li> <li>Karen Strung (Radboud University Nijmegen)</li> <li>Hang Wang (East China Normal University, Shanghai) </li> <li>Michael Whittaker (University of Glasgow)</li> <li>Wilhelm Winter (University of Münster) <strong>TBC</strong></li> <li>Makoto Yamashita (University of Oslo) </li></ul>