Odeljenje za mehaniku, 16. oktobar 2019.

Naredni sastanak Seminara biće održan u sredu, 16. oktobra 2019. u sali 301f Matematičkog instituta SANU sa početkom u 18 časova.

Predavač: Yaron Toledo, Marine Engineering and Physics laboratory (MEPLab), School of mechanical engineering, Tel-Aviv University, Israel

Naslov predavanja: MARINE ENGINEERING AND EAST MED. CURRENTS AND WAVES — AN ATTEMPT TO ACQUIRE A WHOLESOME UNDERSTANDING FROM THEORETICAL, NUMERICAL MODELLING AND FIELD MEASUREMENT PERSPECTIVES

Apstrakt: Any engineering and scientific problem can be approached from various directions. One create its mathematical representation and inspect it directly using accurate numerical methods with high performance computers. Another can approximate these equations in order to enable an easier inspection of its physical properties or allow for real-time operational use. Other approaches include detailed laboratory measurements in order to isolate (as much as possible) effects of different parameters in a controlled environment. If the problem relates to field conditions, it can be measured in the field with the benefit of observing its natural occurrence but with the difficulty of an uncontrolled environment and the noisiness of field conditions.

All the above approaches have their advantages and disadvantages, but it is clear that a combination of these approach can provide a more complete investigation. MEPLab aims to advance the field of marine engineering and our knowledge on ocean waves and currents in the East Mediterranean region using such a multifaceted approach. The talk will present some of the directions taken to reach this goal by combining theory, modelling and field measurements. The second part of the talk will present works on the topics of nonlinear shoaling of wind waves, infra-gravity waves related to harbour agitations and waves of even lower frequencies, which relate to shelf- and bay-scale oscillations.

Nonlinear wave interactions have a significant effect on the wave spectra in the near-shore region with great importance to coastal engineering design. And yet, their calculation still poses significant modelling challenges. Deterministic nonlinear models that account for these interactions are numerically expensive, and hence mostly used for limited computation areas that results in losing a significant part of the spectral evolution effects. Stochastic phase-averaged wave models are commonly used for this purpose as they are efficient enough for resolving large enough computation areas, but they have limited capabilities in accounting for nonlinear shoaling effects. A new nonlinear stochastic formulation extending these models to the nearshore environment will be presented.

Infra-gravity waves are waves that lie outside of the wind-wave spectral regime. They are related to longer wave periods of few tens to few hundreds of seconds. Even though their wave heights are an order of magnitude lower than the ones in the wind wave spectral peak, their comparably large wavelengths (O(1-10km) depending on the bottom depth) can largely influence marine conditions due to basin resonances, harbor agitations and their influence on beach morphology. Their primary generation mechanisms are related to shoaling and breaking of the nearshore wave field. Thus, the focus of most previous related works has been limited to coastal areas.

Based on the analysis of pressure cell measurements, we show evidence of IG wave generation by deep sea storms and present a new mechanism connecting seemingly unrelated phenomena of the comparably slow wind gusts and very fast IG waves. A simulation of IG wave generation, combining reflection of nearshore generated IG waves and deep water generation, shows good agreement with deep water measurements in the Pacific.

Sea level elevation observations ADCPs, tide gauges and wave staves indicate the existence of persistent low-frequency oscillations on the Israeli continental shelf. The dominant frequencies are shown to be consistent with extremely high nonlinear nearshore tide harmonics and shelf resonance models. A shallow water numerical model of Haifa Cape to Achziv shelf edge shows that this constellation enables energy trapping and occurrence of resonating standing waves. It has been found that the resonance periods fit also the ones of tsunami and metro-tsunami events with capability to deep-to-shallow signal increase of up to two orders of magnitude(!) indicating Haifa Bay and Naharia areas to be extremely vulnerable to such events.

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DAAD info-seminar, 18. oktobar 2019.

Matematički fakultet organizuje još jedan otvoreni DAAD info-seminar u petak 18. oktobra 2019. u sali MHA sa početkom od 15 časova.

Na info-seminaru će predstavnici Nemačke službe za akademsku razmenu (DAAD) izložiti mnogobrojne mogućnosti za naučno-istraživačku saradnju i akademsku razmenu sa univerzitetima u Nemačkoj za studente, diplomce, profesore i istraživače.

Pozivamo zainteresovane studente i profesore Matematičkog fakulteta i drugih fakulteta prirodno-matematičke grupacije, kao i drugih institucija Univerziteta u Beogradu da dođu i čuju više o ovim atraktivnim programima, od strane zvaničnika DAAD-a.

Više informacija o DAAD programima, kao i aktivnostima DAAD centra može se naći na stranici  https://www.daad.rs/sr/.

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Pristupno predavanje u okviru konkursa za izbor jednog docenta za užu naučnu oblast: Matematička analiza

Na konkurs se prijavio jedan kandidat: dr Petar Melentijević
Naslov predavanja: „Problem Havinsona za harmonijske funkcije u poluprostoru i lopti u R^n".

Datum, vreme i mesto održavanja: četvrtak, 10.10.2019. godine u 12 časova

Članovi komisije:

- dr Danko Jocić, red. prof.
- dr Olivera Mihić, red. prof.
- dr Stefan Milošević, doc.

Datum objavljivanja: 03.10.2019.

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Odeljenje za matematiku, 7. oktobar 2019.

Naredni sastanak Seminara biće održan u ponedeljak, 7. oktobra 2019. u sali 301f Matematičkog instituta SANU sa početkom u 18 časova.
U pitanju je zajednički sastanak sa Seminarom za logiku.

Predavač: Ilijas Farah, York University, Canada

Naslov predavanja: ULTRAPROIZVODI I ALGEBRE OPERATORA

Apstrakt: Operacije ultraproizvoda i ultrastepena se obično povezuju sa logikom, iako su nezavisno otkrivene u kontekstu operatorskih algebri. U ovom predavanju biće dat pregled ultraproizvoda i njihovih primena u logici, kombinatorici, sa posebnim osvrtom na njihovu ulogu u klasifikaciji C*-algebri. Prethodno predznanje logike i algebri operatora nije neophodno za ovo predavanje.

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Astronomska izložba 'Iznad nas i još dalje', Matematički fakultet u Noći istaživača, 27.i 28. septembar 2019.

Izložba Iznad nas i još dalje (Above and Beyond) skroman je pokušaj navigacije kroz neka od najvažnijih i najspektakularnijih dostignuća u modernoj astronomiji. To je globalno putovanje kroz jedan vek naučnog i tehnološkog napretka i doba nadahnuća koje je proširilo granice čovečanstva i potaklo ljudsku maštu. Izložba je nastala u okviru obeležavanja 100 godina od osnivanja Međunarodne astronomske unije i slavi stogodišnje istraživanje i brojna otkriće do kojih smo došli proučavanjem našeg fascinantnog i tajanstvenog doma - Vasione.

http://nocistrazivaca.rs/sr/mat_fakultet_2019

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Seminar za računarstvo i primenjenu matematiku, 2. oktobar 2019.

Naredni sastanak Seminara biće održan u sredu, 2. oktobra 2019. u sali 301f Matematičkog instituta SANU sa početkom u 18 časova. U pitanju je zajednički sastanak sa Odeljenjem za mehaniku.

Predavač: Aleksandra Ćiprijanović, Matematički institut SANU

Naslov predavanja: PRIMENA MAŠINSKOG UČENjA U ASTRONOMIJI

Apstrakt: U predavanju će biti dat kratak osvrt na dosadašnji naučni rad predavača (A. Ćiprijanović), uz fokus na trenutna istraživanja u oblasti mašinskog učenja. Mašinsko učenje omogućava sistemima da samostalno uče i napreduju kroz iskustvo (bez eksplicitnog programiranja), koristeći veliku količinu podataka i primera na osnovu kojih donose zaključke. Popularnost mašinskog učenja strahovito raste i našla je veoma veliki broj primena u astronomiji, kao jednoj od nauka sa najvećim brojem podataka koje je potrebno obraditi. Biće predstavljena primena dubokog učenja (kao podskup mašinskog učenja koji koristi višeslojne neuronske mreže) za klasifikaciju slika interagujućih galaksija. Ovom tehnikom moguće je istrenirati neuronsku mrežu da razlikuje slike galaksija koje se sudaraju od galaksija koje nisu u interakciji. Važnost ovakvih metoda i buduće primene su velike, od boljeg razumevanja procesa interakcije i sudaranja galaksija, do automatizacije procesa pronalaženja objekata u velikim pregledima neba.

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Odeljenje za mehaniku, 25. septembar 2019.

Naredni sastanak Seminara biće održan u sredu, 25. septembra 2019. u sali 301f Matematičkog instituta SANU sa početkom u 18 časova.

Predavač: Božidar Jovanović, Matematički institut SANU

Naslov predavanja: FILTRACIJE LIJEVIH ALGEBRI I UOPŠTENjE GELFANĐCETINOVIH SISTEMA

Apstrakt: Biće prikazana opšta konstrukcija integrabilnih sistema na kompaktnim Lijevim algebrama dobijenih iz filtracija algebre.

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Seminar za računarstvo i primenjenu matematiku, 20. septembar 2019.

Naredni sastanak Seminara biće održan u petak, 20. septembra 2019. u sali 301f Matematičkog instituta SANU sa početkom u 14:15. U pitanju je zajednički sastanak sa Odeljenjem za matematiku.

Predavač: Anton Kos, Faculty of Electrical Engineering, University of Ljubljana

Naslov predavanja: CHALLENGES IN IMPLEMENTATION OF REAL-TIME BIOFEEDBACK SYSTEMS IN SPORT

Apstrakt: Science and technology are ever more frequently used in sports for achieving the competitive advantage. Motion tracking systems, in connection to the biomechanical feedback, help in accelerating motor learning. The definition of biomechanical biofeedback systems is given along with their intended use.

Biofeedback system architecture, elements, operation, requirements, and versions are presented in detail. Biofeedback system categorization is given: (a) on the basis of architecture, physical extent, and intended functionality, and (b) on constraints expressed in space, communication, processing, and timing requirements. Proposed biofeedback system versions are discussed in the context of the presented constraints and categorization. The most important challenges for the implementation of real-time biofeedback systems in sport are presented and discussed.

Kratka biografija predavača:
Anton Kos received his Ph.D. in electrical engineering from University of Ljubljana, Slovenia, in 2006. He is an assistant professor at the Faculty of Electrical Engineering, University of Ljubljana. He is a member of the Laboratory of Information Technologies at the Department of Communication and Information Technologies. He is the leader of industrial research and development projects in designing of sensor based smart sport equipment and sensor based forestry machinery. His teaching and research work includes communication networks and protocols, quality of service, dataflow computing and applications, use of inertial sensors in biofeedback systems and applications, signal processing, and information systems. He is the (co)author of more than thirty papers appeared in the international engineering journals and of more than fifty papers at international conferences. He is a Senior member of IEEE, Union of Electrical Engineering of Slovenia, and SICOM. Since 2018 he is the Slovenian section ComSOC chapter chair.

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Obaveštenje o raspisivanju konkursa - septembar 2019. godine.

Obaveštenje o raspisivanju konkursa - septembar 2019. godine.

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Studentski seminar, 20. septembar 2019.

Naredni sastanak Seminara biće održan u petak, 20. septembra 2019. u sali 301f Matematičkog instituta SANU sa početkom u 12 časova.

Predavač: IStevan Gajović, Univerzitet u Groningenu

Naslov predavanja: UVOD U ARITMETIČKU VEROVATNOĆU

Apstrakt: U okviru predavanja biće reči o verovatnoći nekih aritmetičkih događaja. Uvodni primeri se odnose na elementarna svojstva celih brojeva, a zatim će biti ispitivane verovatnoće rešivosti nasumične linearne Diofantove jednačine, kao i globalne i lokalne rešivosti kvadratnih formi sa nasumičnim celobrojnim koeficijentima.

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