| ODELJENJE ZA MATEMATIKU
MATEMATICKOG INSTITUTA SANU
| OPSTI MATEMATICKI SEMINAR
NA MATEMATICKOM FAKULTETU U BEOGRADU
-- PROGRAM ZA JUN 2007 --
Petak, 01. jun 2007. u 12h, sala 2 MI SANU:
Adolf Knol, National Library of the Czech Republic
TOWARDS A EUROPEAN DIGITAL LIBRARY OF MANUSCRIPTS
Abstract: The Czech National Library together with 17 full partners and other ca. 10 associated partners from many European countries have expressed the willingness to build a distributed digital library of manuscripts that would provide seamless access to dispersed digital manuscript resources. It will be based on the Czech Manuscriptorium DL that aggregates even today ca. 1,000,000 digitized pages from more than 30 Czech and foreign institutions. By the end of the project, the user will have access to more than 5 million digitized pages and other data as well as to rich catalogue descriptions. The paper will discuss the methods and techniques used to achieve this goal and to support various types of partners and researchers.
Petak, 01. jun 2007. u 14h, sala 2, SANU, BG:
Yuri Fedorov, Departament de Matematica I, Universitat Politecnica de Catalunya, Barcelona, Spain
CLOSED AND ALGEBRAIC CLOSED GEODESICS ON AN ELLIPSOID
Abstract: One of the best known classical integrable systems is the geodesic motion on a triaxial ellipsoid Q in R^3. Apparently, until recently there was no explicit description of closed geodesics on $Q$.
We propose a simple method of explicit description of families of such geodesics on an ellipsoid in R^n that are cut out by algebraic surfaces in $R^n (so called algebraic closed geodesics). Such geodesics are shown to be either connected components of spatial elliptic curves or of rational curves.
Our approach is based on elements of the Weierstrass--Poincare reduction theory for hyperelliptic tangential covers of elliptic curves and a remarkable isomorphism between geodesics on a quadric and stationary solutions of the KdV equation. For the case of 3-fold and 4-fold coverings, explicit formulas for the cutting algebraic surfaces will be provided.
We shall also discuss a relation of this approach with the criteria developed recently by Dragovic and Radnovic.
Petak, 08. jun 2007. sala 2 MI SANU:
Natasa Sladoje, Fakultet tehnickih nauka, Novi Sad
ON ANALYSIS OF DISCRETE SPATIAL FUZZY SETS IN 2 AND 3 DIMENSIONS
Abstract: The advantages of representing objects in images as fuzzy spatial sets are numerous and have lead to increased interest for fuzzy approaches in image analysis. Fuzziness is an intrinsic property of images. It is additionally introduced in digital image processing by discretization, and as a natural outcome of most imaging devices. Preservation of fuzziness implies preservation of important information about objects and images. Therefore, fuzziness should, in general, be kept and utilized as long as possible when analyzing the image data.
In this talk, main results of our research related to the development of shape analysis methods that can be applied to fuzzy segmented images in 2D and 3D will be presented. We have studied a number of known shape descriptors: (1) geometric moments; (2) the signature of a shape based on the distance from the shape centroid; (3) the measurements of area, perimeter, and compactness, as well as of volume, surface area, and sphericity. We have shown, either theoretically, or through statistical studies, that the precision of estimation of the studied features of a continuous shape is increased if a fuzzy discrete representation of the shape is used, instead of a crisp one. In addition, we have designed a defuzzification method based on feature invariance, utilizing the improved estimates of shape characteristics from fuzzy sets to generate crisp discrete shapes with the most similar shape characteristics.
The presented results can be applied wherever precise estimates of shape properties are equired, especially in conditions of limited spatial resolution.
Petak, 15. jun 2007. u 14h, sala 2, MI SANU, BGD:
Djordje Kadijevic, Matematicki Institut SANU
O KOMPLEKSNOSTI ISTRAZIVANJA U NASTAVI MATEMATIKE
Rezime: U predavanju se prikazuju specificnosti istrazivanja u nastavi matematike i ukazuje na njihovu kompleksnost. Ova kompleksnost se detaljno ilustruje za temu povezivanje proceduralnog i konceptualnog matematickog znanja posredstvom CAS (softvera za racunarsku algebru).
Petak, 22. jun 2007. u 14h, sala 718, MF BG:
Miljan Knezevi?, Matematicki fakultet, Beograd
ON THE QUASI-ISOMETRIES OF HARMONIC QUASICONFORMAL MAPPINGS
Abstract: We prove versions of the Ahlfors-Schwarz lemma for quasiconformal euclidean harmonic functions and harmonic mappings with respect to the Poincaré metric.
Predavanja ce se odrzavati na Matematickom Institutu (sala 2), petkom sa pocetkom u 14 casova. Odeljenje za matematiku je opsti seminar sa najduzom tradicijom u Institutu.
Svakog meseca, jedno predavanje ce biti odrzano na Matematickom Fakultetu u terminu koji ce biti posebno odredjen.
Molimo sve zainteresovane ucesnike u radu naucnih sastanaka da posebno obrate paznju na vreme odrzavanja svakog sastanka. Na Matematickom fakultetu su moguce izmene termina.
Obavestenje o programu naucnih sastanaka ce biti objavljeno na oglasnim tablama MI (Beograd), MF (Beograd), PMF (Novi Sad), PMF (Nis) i PMF (Kragujevac).
Odeljenje za matematiku Matematickog instituta SANU
Opsti matematicki seminar na Matematickom fakultetu u Beogradu,
Ako zelite da se obavestenja o Vasim naucnim skupovima pojave u Newsletter of EMS (European Mathematical Society) i na Internetu na lokaciji EMS, onda se obratite na firstname.lastname@example.org gde cete dobiti format obavestenja.