Händelser: Matematiska vetenskaperhttp://www.chalmers.se/sv/om-chalmers/kalendariumAktuella händelser på Chalmers tekniska högskolaTue, 02 Mar 2021 18:42:53 +0100http://www.chalmers.se/sv/om-chalmers/kalendariumhttps://www.chalmers.se/sv/institutioner/math/kalendarium/Sidor/Computational210303.aspxhttps://www.chalmers.se/sv/institutioner/math/kalendarium/Sidor/Computational210303.aspxComputational and Applied Mathematics (CAM) seminar<p>MVL:14 and Zoom</p><p>​Raphael Kruse​, Martin-Luther-University Halle-Wittenberg: Discretization of Elliptic PDEs with the Finite Element Method and Randomized Quadrature Formulas​</p><p>​<br />Abstract: The implementation of the finite element method for linear elliptic partial differential equations (PDE) requires to assemble the stiffness matrix and the load vector. In general, the entries of this matrix-vector system are not known explicitly but need to be approximated by quadrature rules. However, if the coefficient functions of the differential operator or the forcing term are irregular, then standard quadrature formulas, such as the barycentric quadrature rule, may not be reliable. In this talk we discuss the application of two randomized quadrature formulas to the finite element method for such elliptic PDE with irregular coefficient functions. We derive detailed error estimates for these methods, discuss their implementation in in numerical experiments.</p> <p>This talk is based on joint work with Nick Polydorides (U Edinburgh) and Yue Wu (U Oxford).​</p>https://www.chalmers.se/sv/institutioner/math/kalendarium/Sidor/Algebraisk-geometri210303.aspxhttps://www.chalmers.se/sv/institutioner/math/kalendarium/Sidor/Algebraisk-geometri210303.aspxSeminariet i Algebraisk geometri och talteori<p>Online</p><p>​Per Salberger, Chalmers/GU: On n-torsion in class groups of number fields</p>​<br />Abstract: It is well known that the class group of a number field is of size bounded above by roughly the square root of its discriminant. But one expects by conjectures of Cohen-Lenstra that the the n-torsion part of this group should be much smaller and there have recently been several papers on this by prominent mathematicians. We present in our talk some new bounds which are sharper than those in the literature.https://www.chalmers.se/sv/institutioner/math/kalendarium/Sidor/Examensarbete210305.aspxhttps://www.chalmers.se/sv/institutioner/math/kalendarium/Sidor/Examensarbete210305.aspxPresentation av examensarbete<p>Online</p><p>​Avijit Singh: Design and analysis of pre-clinical experiments using a method combining multiple comparisons and modeling techniques for dose-response studies</p>​<br />Abstract: In the preclinical stage of pharmaceutical drug development, identifying and estimating the dose-response relationship between a compound and a clinical endpoint of interest is one of the most important and difficult goals. In the drug development process, two main goals of dose-response studies are (i) to establish that changes in dose lead to desirable (efficacy) or acceptable (safety) changes in the endpoint(s) of interest and (ii) to select a dose (or doses) that appears to be efficacious and safe. The aim of this thesis is to provide an overview of existing techniques and design the experiments which are appropriate for addressing both of these goals simultaneously. We have used a method combining multiple comparisons and modeling techniques (MCPMod) in designing the experiments and found out that we can reduce the required total sample size by using optimal design without affecting results negatively. We have analysed simulated data using MCPMod and observed that this method can be used to identify dose-response relationships and estimate doses at the required effect. We have compared two approaches of estimating doses and discovered that using a weighted average of all fitted models gives a similar result as compared to using the best fitted model. Finally we have investigated the possibility of detecting the presence of toxicity in response of few or many samples at higher doses and found that we can detect toxicity if there are many samples with toxic response at higher doses. https://www.chalmers.se/sv/institutioner/math/kalendarium/Sidor/Computational210310.aspxhttps://www.chalmers.se/sv/institutioner/math/kalendarium/Sidor/Computational210310.aspxComputational and Applied Mathematics (CAM) seminar<p>MVL:14 and Zoom</p><p>Patrick Henning​, Ruhr-Universität Bochum: The approximation and conservation of energy in nonlinear Schrödinger equations</p><p><br />Abstract: In this talk we consider the numerical treatment of nonlinear Schrödinger equations as they appear for example in quantum physics and fluid dynamics. We give numerical examples that demonstrate the influence of the discrete energy on the accuracy of numerical approximations and that a spurious energy can create artificial phenomena such as drifting particles. In order to conserve the exact energy of the equation as accurately as possible, we propose a Crank-Nicolson-type time discretization that is combined with a suitable generalized finite element discretization in space. The space discretization is based on the technique of Localized Orthogonal Decompositions (LOD) and allows to capture general time invariants with a 6th order accuracy with respect to the chosen mesh size H. This accuracy is preserved due to the conservation properties of the time stepping method. The computational efficiency of the method is demonstrated for a numerical benchmark problem with known exact solution, which is however not solvable with traditional methods on long time scales.​</p>https://www.chalmers.se/sv/institutioner/math/kalendarium/Sidor/Informationsmote-masterprogram210310.aspxhttps://www.chalmers.se/sv/institutioner/math/kalendarium/Sidor/Informationsmote-masterprogram210310.aspxInformationsmöte om Masterprogrammen i Matematik<p>Online</p><p></p>​På mötet kommer vi berätta om våra två masterprogram: Masterprogram i Matematiska vetenskaper och Masterprogrammet i Matematik och Lärande. Ni kommer även få höra från lärare på de olika inriktningarna på det förstnämnda programmet.https://www.chalmers.se/sv/institutioner/math/kalendarium/Sidor/KASS-seminar210311.aspxhttps://www.chalmers.se/sv/institutioner/math/kalendarium/Sidor/KASS-seminar210311.aspxKASS seminar<p>Online</p><p>​Mingchen Xia: Pluripotential-theoretic approach to global geometric problems in Kähler geometry</p>​<br />Abstract: We discuss global pluripotential theory on a compact Kähler manifold and its relation to various geometric problems of the manifold. In particular, we discuss how to translate functionals on the set of geodesic rays in the space of Kähler potentials into functionals of quasi-plurisubharmonic functions and functionals of the associated non-Archimedean data. As an application, we show that on a Fano manifold X, we can define a delta-type invariant using quasi-plurisubharmonic functions,  which effectively detects the K-stability of X.https://www.chalmers.se/sv/institutioner/math/kalendarium/Sidor/Institutionskollegium210315.aspxhttps://www.chalmers.se/sv/institutioner/math/kalendarium/Sidor/Institutionskollegium210315.aspxInstitutionskollegium<p>Online</p><p>​Besök från Genie</p>​<br />Vid detta kollegiemöte får vi besök av ledarna för Genie, Pernilla Wittung-Stafshede och Mary Sheeran. https://www.chalmers.se/sv/institutioner/math/kalendarium/Sidor/Pi-dagen-2021.aspxhttps://www.chalmers.se/sv/institutioner/math/kalendarium/Sidor/Pi-dagen-2021.aspxPi-dagen<p>Online</p><p>​Johan Wästlund: Pi och summan av kvadraternas inverser, från Euler till Youtube</p>​<br /><img class="chalmersPosition-FloatRight" alt="Illustration pi-dagen" src="/SiteCollectionImages/Institutioner/MV/Kalendarium/Pi_illustration250x250.png" style="margin:5px" />Frågan om summan 1+1/4+1/9+... av kvadrattalens inverser kallades Baselproblemet, och löstes av Leonhard Euler på 1700-talet. Summan är lika med pi^2/6, och många bevis är idag kända. Ett särskilt vackert och enkelt geometriskt resonemang går på sätt och vis tillbaka till Cauchy, men har utvecklats av flera andra matematiker genom åren. Jag har även själv bidragit till detta stycke ”folkmatematik”, som nu är känt genom Youtube som ”the lighthouse proof”. https://www.chalmers.se/sv/institutioner/math/kalendarium/Sidor/Statistics210316.aspxhttps://www.chalmers.se/sv/institutioner/math/kalendarium/Sidor/Statistics210316.aspxStatistics seminar<p>Online</p><p>​Fredrik Lindsten, Linköping University: TBA</p>​<br />Organiser: Umberto Picchini (picchini@chalmers.se). Please contact me if you wish to be informed of future seminars.https://www.chalmers.se/sv/institutioner/math/kalendarium/Sidor/Computational210317.aspxhttps://www.chalmers.se/sv/institutioner/math/kalendarium/Sidor/Computational210317.aspxComputational and Applied Mathematics (CAM) seminar<p>MVL:14 and Zoom</p><p>​Luigi Brugnano​, Università di Firenze: Spectral numerical solution of evolutionary problems</p><p><br />​Abstract: In this talk, I will briefly recall recent results on the use of spectral methods for the efficient numerical solution of evolutionary problems. Their main feature is the ability of obtaining full machine accuracy despite the use of (relatively) large time-steps. This approach, at first devised for solving highly-oscillatory problems [1], has then been extended to the numerical solution of Hamiltonan PDEs [2], general ODE-IVPs [3], and fractional ODEs [4]. A theoretical analysis of the methods has been given in [5]. </p> <p>[1] L.Brugnano, J.I.Montijano, L.Rández. On the effectiveness of spectral methods for the numerical solution of multi-frequency highly-oscillatory Hamiltonian problems. Numerical Algorithms 81 (2019) 345-376.</p> <p>[2] L.Brugnano, F.Iavernaro, J.I.Montijano, L.Randez. Spectrally accurate space-time solution of Hamiltonian PDEs. Numerical Algorithms 81 (2019) 1183-1202.</p> <p>[3] P.Amodio, L.Brugnano, F.Iavernaro, C.Magherini. Spectral solution of ODE-IVPs using SHBVMs. AIP Conference Proceedings 2293 (2020) 100002.</p> <p>[4]  P.Amodio, L.Brugnano, F.Iavernaro. Spectrally accurate solutions of nonlinear fractional initial value problems. AIP Conference Proceedings 2116 (2019) 140005.</p> <p>[5] P.Amodio, L.Brugnano, F.Iavernaro. Analysis of Spectral Hamiltonian Boundary Value Methods (SHBVMs) for the numerical solution of ODE problems. Numerical Algorithms 83 (2020) 1489-1508.</p>https://www.chalmers.se/sv/institutioner/math/kalendarium/Sidor/Statistics210330.aspxhttps://www.chalmers.se/sv/institutioner/math/kalendarium/Sidor/Statistics210330.aspxStatistics seminar<p>Online</p><p>​Manuela Zucknick, University of Oslo: TBA</p>​<br />Organiser: Umberto Picchini (picchini@chalmers.se). Please contact me if you wish to be informed of future seminars.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>​​<br /><em>N.B.! The dates are preliminary!</em></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>