BEGIN:VCALENDAR VERSION:2.0 PRODID:researchseminars.org CALSCALE:GREGORIAN X-WR-CALNAME:researchseminars.org BEGIN:VEVENT SUMMARY:Mina Teicher (Department of Mathematics and Gonda Brain Research C enter\, Bar-Ilan University\, Israel) DTSTART:20201210T081500Z DTEND:20201210T090500Z DTSTAMP:20260422T212707Z UID:WMSEE/1 DESCRIPTION:Title: Ma thematics for analyzing brain activity\nby Mina Teicher (Department of Mathematics and Gonda Brain Research Center\, Bar-Ilan University\, Israe l) as part of Women in Mathematics in South-Eastern Europe\n\n\nAbstract\n Studying the brain and analyzing brain activity is on the forefront of sci ence today. It is connected to Robotics\, Artificial intelligence\, brain disorders\, artificial organs and more. For the last decades\, brain scien tists believed that the main model to which the brain is subject to is fir ing rate and did not believe in synchronization. In this talk we will desc ribe a research project that sheds light on the theoretical question how d oes the brain work\, and in particular proves synchronization in brain act ivity of behaving animals. Moreover\, we shall mention briefly few project s in clinical medicine of the brain – epilepsy and sleep disorders.\n LOCATION:https://researchseminars.org/talk/WMSEE/1/ END:VEVENT BEGIN:VEVENT SUMMARY:Sofia Lambropoulou (School of Applied Mathematical and Physical Sc iences\, National Technical University of Athens\, Greece) DTSTART:20201210T093000Z DTEND:20201210T102000Z DTSTAMP:20260422T212707Z UID:WMSEE/2 DESCRIPTION:Title: On Knotoids and Applications\nby Sofia Lambropoulou (School of Applied M athematical and Physical Sciences\, National Technical University of Athen s\, Greece) as part of Women in Mathematics in South-Eastern Europe\n\n\nA bstract\nAbstract: The theory of knotoids\, introduced by Turaev in 2011\, extends classical knot theory. In this talk we review some aspects of the theory of knotoids and present some recent developments with a focus on s ingular knotoids. We also discuss applications in the topological study of proteins.\n LOCATION:https://researchseminars.org/talk/WMSEE/2/ END:VEVENT BEGIN:VEVENT SUMMARY:Natasa Krejic (Faculty of Science\, University of Novi Sad\, Serbi a) DTSTART:20201210T120000Z DTEND:20201210T125000Z DTSTAMP:20260422T212707Z UID:WMSEE/3 DESCRIPTION:Title: In exact Restoration Methods for Finite Sum Minimization\nby Natasa Kreji c (Faculty of Science\, University of Novi Sad\, Serbia) as part of Women in Mathematics in South-Eastern Europe\n\n\nAbstract\nConvex and nonconvex finite-sum minimization arises in many scientific computing and machine l earning applications. Recently\, first-order and second-order methods wher e objective functions\, gradients and Hessians are approximated by randoml y sampling components of the sum have received great attention. We discuss a class of methods which employs suitable approximations of the objective function\, gradient and Hessian built via random subsampling techniques. The choice of the sample size is deterministic and ruled by the Inexact Re storation approach. Local and global properties for finding approximate fi rst- and second-order optimal points and function evaluation complexity re sults are discussed in the framework of line search and trust region metho ds.\n LOCATION:https://researchseminars.org/talk/WMSEE/3/ END:VEVENT BEGIN:VEVENT SUMMARY:Nadezhda Ribarska (Faculty of Mathematics and Informatics\, Sofia University “St. Kliment Ohridski”\, Bulgaria) DTSTART:20201210T132000Z DTEND:20201210T141000Z DTSTAMP:20260422T212707Z UID:WMSEE/4 DESCRIPTION:Title: On a non-smooth problem of the calculus of variations\nby Nadezhda Ribar ska (Faculty of Mathematics and Informatics\, Sofia University “St. Klim ent Ohridski”\, Bulgaria) as part of Women in Mathematics in South-Easte rn Europe\n\n\nAbstract\nThe specificity of the basic problem of the calcu lus of variations considered as a constraint optimization problem on an in finite-dimensional space is discussed. A sufficient condition for tangenti al transversality involving measures of non-compactness as well as a Lagra nge multiplier theorem for the infinite-dimensional optimization problem a re obtained. The relation of the obtained results to the basic problem of calculus of variations is discussed.\n\nThe talk is based on a joint work with Mikhail Krastanov.\n LOCATION:https://researchseminars.org/talk/WMSEE/4/ END:VEVENT BEGIN:VEVENT SUMMARY:Ana Irina Nistor (Department of Mathematics and Informatics “Gh. Asachi” Technical University of Iasi\, Romania) DTSTART:20201211T080000Z DTEND:20201211T085000Z DTSTAMP:20260422T212707Z UID:WMSEE/5 DESCRIPTION:Title: Ma gnetic trajectories on almost contact metric manifolds\nby Ana Irina N istor (Department of Mathematics and Informatics “Gh. Asachi” Technica l University of Iasi\, Romania) as part of Women in Mathematics in South-E astern Europe\n\n\nAbstract\nThis presentation consists in a collection of results obtained so far in the study of magnetic trajectories as well as some future work. As the study of magnetic trajectories was intensively de veloped in Kaehler manifolds\, where the Kaehler 2-form is closed and henc e defines a magnetic field\, we investigate the magnetic curves in quasi-S asakian manifolds. In\nparticular\, the magnetic curves in Sasakian and co symplectic manifolds of arbitrary dimension are classified. The 3-dimensio nal case is quite important\, as it is well known that the geometry of qua si-Sasakian 3-manifolds is rather special and we will present the results obtained in the study of magnetic trajectories.\n LOCATION:https://researchseminars.org/talk/WMSEE/5/ END:VEVENT BEGIN:VEVENT SUMMARY:Betul Bulca (Department of Mathematics\, Uludağ University\, Burs a\, Turkey) DTSTART:20201211T093000Z DTEND:20201211T102000Z DTSTAMP:20260422T212707Z UID:WMSEE/6 DESCRIPTION:Title: Th e theory and the geometric modelling of curves and surfaces in Euclidean s paces\nby Betul Bulca (Department of Mathematics\, Uludağ University\ , Bursa\, Turkey) as part of Women in Mathematics in South-Eastern Europe\ n\n\nAbstract\nIn this talk we give the theory of the curves and surfaces in Euclidean spaces. We give some basic concepts of the surfaces especiall y in Euclidean four space. In this study\, the well- known geometric model ing and interpolation methods for curves and surfaces will be emphasized a nd also the studies in this area will be mentioned. Some well-known surfac es (such as rotational surface family) will be discussed and examples of t hese surfaces will be given. Also we present our recent works on the geome tric modelling of the biological plants. Further\, we discuss the Bezier i nterpolation methods with curves in Euclidean 4-space.\n LOCATION:https://researchseminars.org/talk/WMSEE/6/ END:VEVENT BEGIN:VEVENT SUMMARY:Velichka Milousheva (Institute of Mathematics and Informatics\, Bu lgarian Academy of Sciences\, Bulgaria) DTSTART:20201211T120000Z DTEND:20201211T125000Z DTSTAMP:20260422T212707Z UID:WMSEE/7 DESCRIPTION:Title: Ma rginally trapped (quasi-minimal) surfaces in pseudo-Euclidean 4-spaces \nby Velichka Milousheva (Institute of Mathematics and Informatics\, Bulga rian Academy of Sciences\, Bulgaria) as part of Women in Mathematics in So uth-Eastern Europe\n\n\nAbstract\nA surface in a pseudo-Riemannian manifol d is called quasi-minimal if its mean curvature vector is lightlike at eac h point of the surface. When the ambient space is the Lorentz-Minkowski sp ace\, the quasi-minimal submanifolds are also called marginally trapped – a notion borrowed from General Relativity. The concept of trapped surf aces was first introduced by Sir Roger Penrose in 1965 in connection with the theory of cosmic black holes.\n\nMarginally trapped surfaces in spacet imes satisfying some extra conditions have recently been\nintensively stud ied in connection with the rapid development of the theory of black holes in Physics. Most of the results give a complete classification of marginal ly trapped surfaces under some additional geometric conditions\, such as h aving positive relative nullity\, having parallel mean curvature vector fi eld\, having pointwise 1-type Gauss map\, being invariant under spacelike rotations\, under boost transformations\, or under the group of screw rota tions.\n\nQuasi-minimal surfaces in the pseudo-Euclidean 4-space with neut ral metric satisfying some additional conditions have also been studied ac tively in the last few years. Most of the results are due to Bang-Yen Chen and his collaborators.\n\nIn this talk we will give an overview of these classification results and present the Fundamental existence and uniquenes s theorem for the general class of quasi-minimal Lorentz surfaces in the p seudo-Euclidean 4-space with neutral metric.\n LOCATION:https://researchseminars.org/talk/WMSEE/7/ END:VEVENT BEGIN:VEVENT SUMMARY:Sanja Atanasova (Faculty of Electrical Engineering and Information Technologies\, “Ss. Cyril and Methodius” University in Skopje\, North Macedonia) DTSTART:20201211T132000Z DTEND:20201211T141000Z DTSTAMP:20260422T212707Z UID:WMSEE/8 DESCRIPTION:Title: In tegral transforms through the prism of distribution theory\nby Sanja A tanasova (Faculty of Electrical Engineering and Information Technologies\, “Ss. Cyril and Methodius” University in Skopje\, North Macedonia) as part of Women in Mathematics in South-Eastern Europe\n\n\nAbstract\nThe Fo urier transform is probably the most widely applied signal processing tool in science and engineering. It reveals the frequency composition of a tim e series by transforming it from the time domain into the frequency domain . However\, it does not reveal how the signals frequency contents vary wit h time. A straightforward solution to overcoming the limitations of the Fo urier transform the concept of the short-time Fourier transform (STFT). Th e short-time Fourier transform is a very effective device in the study of function spaces. However\, significant barrier in application of the STFT is the fact that the fixed window function has to be predefined\, which le ads to a poor time-frequency resolution and\, in general\, the absence of a sufficiently good reconstruction algorithm. The Wavelet transform (WT) i s used to overcome some of the shortcomings of the STFT. With the dilatati on and translation of the window function\, the WT has better phase modula tion in the spectral domain. However\, the self-similarity caused by the t ranslation and the overlap in the frequency domain becomes non-avoidable s ince they do not permit straightforwardly the transfer of scale informatio n into proper frequency information. The Stockwell transform (ST) also dec omposes a signal into temporal and frequency components. In contrast to th e WT\, the ST exhibits a frequency-invariant amplitude response and covers the whole temporal axis creating full resolutions for each designated fre quency. It is invertible\, and recovers the exact phase and the frequency information without reconstructing the signal. The problem with the ST is its redundancy. But\, there have been different strategies in order to imp rove the performance and the application of the ST.\n\nOn the other hand\, the STFT\, as a tool of the time-frequency analysis\, contains localized time and frequency information of a function. Another idea is to localize information in time\, frequency\, and direction\, which leads to direction ally sensitive variant of STFT\, which gives the Directional short time Fo urier transform (DSTFT).\n\nIn mathematics\, distributions extend the noti on of functions. Distribution theory is a power tool in applied mathematic s and the extension of integral transforms to generalized function spaces is an important subject with a long tradition. The theory is developed by proving that these transforms are well defined on the appropriate spaces o f distribution. These is done by proving continuity results for these tran sforms on so called test function spaces\, and then extending the definiti ons on distributions. In this talk\, i consider several integrals transfor ms (STFT\, WT\, ST\, DSTFT) and try to make short survey on their behaviou r on distributions.\n\nThere are several approaches to the theory of distributions\, but in all of them one quickly learn that distri butions do not have point values\, as functions do\, despite the fact that they are called generalized functions. Natural generalization of this notion is the quasiasymptotic behavior of distributions. It is an old su bject that has found applications in various fields of pure and app lied mathematics\, physics\, and engineering. In the second part of my talk\, I use Abelian and Tauberian ideas for asymptotic analysis of the mentioned integral transforms to characterize the asymptotic properties of a distribution.\n LOCATION:https://researchseminars.org/talk/WMSEE/8/ END:VEVENT END:VCALENDAR