Digest of the Non Linear Science Network, Volume 16, Number 02 February 1, 2016 Editor: Angel Jorba Topics: International Conference on Nonlinear Dynamics European Nonlinear Dynamics Conference - ENOC 2017 Conference on Geometry, Integrability and Quantization 115th Statistical Mechanics Conference Seminar, Differential Equations, Dynamical Systems and Applications Workshop on Non-Spatial Stochastic Dynamical Systems A 2-year postdoc position Postdoc Position, Fluid Dynamics Lecturer Position, Applied Mathematics Contents, Discrete and Continuous Dynamical Systems - Series B 21:3 Contents, Journal of Dynamics and Games 2:3-4 Contents, Communications on Pure and Applied Analysis 15:2 Submissions to nls-net must be addressed to: Comments and suggestions are also welcome. General information about nls-net can be found at: http://www.maia.ub.es/cgi-bin/mailman/listinfo/nls-net/ This is a service created and maintained in collaboration with the American Institute of Mathematical Sciences (AIMS) http://www.aimsciences.org/ ------ Subject: International Conference on Nonlinear Dynamics From: ND-KhPI 2016 Organizing Committee Date: Thu, 21 Jan 2016 17:24:46 +0200 5-th International Conference on Nonlinear Dynamics dedicated to the 90th anniversary of Academician Rvachev V.L. ND-KhPI 2016 Kharkov, Ukraine, 27-30 September, 2016. Dear Colleagues, We would like to invite you to participate in the 5-th International Conference on Nonlinear Dynamics wich will be held at the National Technical University "Kharkov Polytechnical Institute" (NTU "KhPI") Kharkov, Ukraine on 27-30 September, 2016. The working language of the conference is ENGLISH. Subscribe to the ND-KhPI2016 news now to receive updates as they occur. (to subscribe click here https://docs.google.com/forms/d/1Kbjh91RlmnRMnRn7Xy93G1MdHhgFrLNow1Agb2OVVOQ/viewform?usp=send_form) The conference is devoted to the recent developments on the various problems of nonlinear dynamic (theoretical aspects and engineering applications). Topic areas: Analytical and Numerical Methods in Nonlinear Dynamics; Resonances, Stability Analysis and Bifurcations in Nonlinear Systems; Nonlinear Normal Modes; Transient, Localization of Energy; Chaotic Dynamics; Nonlinear Dynamics of Continuous Systems, in particular, Plates and Shells; Vibro-Impact Systems and other Non-Smooth Systems; Problems of Control in Nonlinear Systems; Nonlinear Dynamics of Structures and Machines and other problems of Engineering Applications. Invited Speakers include: MARCO AMABILI (Montreal, Canada) JOSE M. BALTHAZAR (Sao Jose dos Campos, Brasil)LEONID I. MANEVITCH (Moscow, Russia) CHRISTOPHE PIERRE (Urbana - Champaign, USA) GIUSEPPE REGA (Roma, Italy) ALEXANDER VAKAKIS (Urbana - Champaign, USA) Conference organizers consider as their pleasant duty to notice the approaching 100th anniversary of the outstanding Ukrainian mathematician, Academician Yu. A. Mitropolsky, who contributed immensely to asymptotic methods of nonlinear dynamics. Within the framework of the conference the following mini-symposium will take place: "The R-FUNCTIONS THEORY, ITs DEVELOPMENT and RECENT APPLICATIONS". The main goal of this Mini-Symposium is focused on the discussion of the R-functions theory application to the problems of nonlinear dynamics solution. A development of new trends and constructive tools in a theory of R-functions as well as applications of the R-functions and others effective instruments for approximation procedures (splines, wavelets, Up-functions, etc.) in solution of a boundary value problems for an objects with a complex geometrical shape will be discussed. During the conference, a limited number of WEB-PRESENTATIONS is planned for some outstanding works. These presentations will be organized in a web-conference format. A web-presentation is planned only for international participants who will not be able to visit the conference on the Organizing Committee agreement. For further information, please visit the ND-KhPI2016 website http://web.kpi.kharkov.ua/nd-khpi/ or contact the organizing committee: Email: NDKhPI2016@gmail.com ------ Subject: European Nonlinear Dynamics Conference - ENOC 2017 From: ENOC 2017 Date: Tue, 26 Jan 2016 06:30:08 +0000 Dear Colleagues, It is my pleasure to invite you to attend the 9th European Nonlinear Dynamics Conference (ENOC 2017) in Budapest, Hungary. The Conference will be held next year on 25-30 June, 2017 at the campus of Budapest University of Technology and Economics. Budapest is an ideal setting to discuss current progress in the research of nonlinear dynamics. Our capital is a city of outstanding geographical location with great traditions, wonderful historical places, as well as plenty of prestigious hotels within walking distance to the venue and to downtown Budapest. According to the traditions of ENOC conferences, the scientific programme will be structured to numerous minisymposia on major and challenging pre-defined topics, organized by well-recognized scientists. I hope to welcome as many of you as possible in Budapest at this conference in order to exchange and improve our knowledge in the diverse fields of nonlinear dynamics. Gabor Stepan Chair of ENOC 2017 Important dates: * September 2016: Call for papers * December 2016: Submission of 2-page abstract * February 2017: Notification of authors * April 2017: Early-bird registration and submission of final paper (optional) * 25-30 June, 2017: ENOC 2017 Conference DOWNLOAD ENOC 2017 FIRST ANNOUNCEMENT: http://congressline.us4.list-manage.com/track/click?u=28793f6a351849b35e245cfc8&id=8a70174e6e&e=1f7298b4bd ------ Subject: Conference on Geometry, Integrability and Quantization From: "Ivailo M. Mladenov" Date: Thu, 28 Jan 2016 13:59:04 +0200 Dear Colleague, It is my pleasure to inform you about the XVIII-th Edition of the Varna Conference on Geometry, Integrability and Quantization which will take place in June 03-08, 2016. For more detail, please visit the permanent webpage of the meeting at http://www.bio21.bas.bg/conference Since the beginning of 2015 all Conference Proceedings are a part of Euclid Prime Collection https://projecteuclid.org/all/euclid.pgiq and those which are more than 5 years older are freely available on AMS and EMS servers. Hoping that we will meet in Varna, I remain, Sincerely yours, Ivailo Mladenov web: http://www.bio21.bas.bg/ibf/dpb_files/im/Mladenov.htm ------ Subject: 115th Statistical Mechanics Conference From: Avishag Klatzkin Date: Mon, 1 Feb 2016 13:42:21 -0500 115th Statistical Mechanics Conference RUTGERS UNIVERSITY, BUSCH CAMPUS, HILL CENTER, ROOM 114 SUNDAY, MONDAY AND TUESDAY, May 8 - 10, 2016 Dear Colleague: You are cordially invited to participate in the 115th Statistical Mechanics Conference at Rutgers University, May 8 - 10, 2016. At this meeting, we will celebrate the achievements of our guests of honor: David Chandler, John Weeks and Julia Yeomans. Here is a tentative list of speakers: Gareth Alexander, Hans C. Andersen, Eva Y. Andrei, Igor Aronson, Angelo Bassi, Bruce Berne, Peter Bolhuis, Francesco Cellarosi, Paul Chaikin, Arup K. Chakraborty, Gavin Crooks, Christoph Dellago, Colin Denniston, Carl Dettmann, Jorn Dunkel, Massimiliano Esposito, Michael Fisher, Juan P. Garrahan, William Gelbart, Subhro Ghosh, Sharon Glotzer, Alex Greer, David Huse, Tuommas Knowles, Halim Kusuaatmaja, Albert Libchaber, David Limmer, Erik Luijten, Jonathan Machta, Lawrence Pratt, Sidney Redner, David R. Reichman, Yasser Roudi, Eric Siggia, Frank Stillinger, John Tully, Bruce Turkington, Suriyanarayanan Vaikuntanathan Please register on our website both for attendance and for presenting a short talk.You will find there options to either pay online or pay at the door by cash or check. You may also register and mail your payment by check in advance. Visit our website at http://www.math.rutgers.edu/events/smm/index.html and select from the registration options listed. All details of the meeting (i.e. lodging, transportation, abstracts, etc.) are also posted on the website. Please let us know of any colleagues or students who should be added to our mailing list. Also, please send us information about positions wanted or available, etc. Looking forward to seeing you here. With best wishes, Joel Professor Joel L. Lebowitz lebowitz@math.rutgers.edu Center for Mathematical Sciences Research 110 Frelinghuysen Road, Piscataway, NJ 08854-8019 FAX: 732-445-4936 PHONE: 848-445-3117 ------ Subject: Seminar, Differential Equations, Dynamical Systems and Applications From: reza mazrooei Date: Sat, 30 Jan 2016 11:06:49 +0330 (IRST) 13th International Seminar on Differential Equations, Dynamical Systems and Applications July 13-15, 2016 http://deds13.iut.ac.ir Seminar on Differential Equations, Dynamical Systems and Applications is one of the seminars sponsored by Iranian mathematical society with emphasis on special topics which holds in different universities in Iran. The Thirteenth of these seminars (DEDS13, 2016) will be held from July 13 to July 15, 2016 in Isfahan and cosponsored by Isfahan University of Technology, Iranian mathematical society and institute for research in fundamental sciences. The topics to be covered in this seminar include : * Continuous-Time and Discrete-Time Dynamical systems (Chaos, Bifurcation theory, Hamiltonian Systems, Symmetric Systems, Ergodic Theory, ...), * Qualitatative theory of ordinary differential equations (Classic Theory, Hilbert's sixteenth problem, Boundary value problems, ...) * Complex dynamical systems (Julia set, Fractals, ...) * Numerical methods in bifurcation theory * Numerical solutions of differential equations (Deterministic and Stochastic) * Partial differential equations, Evolution equations * Applications (Mathematical Biology, Mechanics, Economics, Telecommunications and Computer Science, Inverse problems, Financial mathematics, Control theory, ...) * Stochastic dynamical systems (Ordinary and Partial differential equations, ...) Invited Speakers Ferdinand Verhulst, Utrecht University, Netherlands Martin Rasmussen, Imperial College London, England Hil Meijer, Twente University, Netherlands Hans Crauel, Goethe University, Germany Fraydoun Rezakhanlou, University of California, USA Henrik Shahgholian, The Royal Institute of Technology, Stokholm, Sweden Hossein Movasati, IMPA-Institue de Matematica Pura e Aplicada, Brazil Hayk Mikayelyan, Nottingham Ningbo University, China Reza Pakzad, Pittsburgh University, USA Organizing Commitee, Mazrooei-Sebdani, Reza, Isfahan University of Technology, Isfahan, Iran, Chairman of Seminar Zangeneh, Hamid R. Z., Isfahan University of Technology, Isfahan, Iran Hashemi, Amir, Isfahan University of Tecnology, Isfahan, Iran Mokhtari, Reza, Isfahan University of Technology, Isfahan, Iran Raoofi, Mohammadreza, Isfahan University of Tecnology, Isfahan, Iran Asheghi, Rasoul, Isfahan University of Technology, Isfahan, Iran ------ Subject: Workshop on Non-Spatial Stochastic Dynamical Systems From: David Anderson Date: January 18, 2016 ADVANCES IN NUMERICAL AND ANALYTIC APPROACHES FOR THE STUDY OF NON-SPATIAL STOCHASTIC DYNAMICAL SYSTEMS IN MOLECULAR BIOLOGY 4 April, 2016 - 8 April, 2016 INI, Cambridge, England, United Kingdom This workshop focuses on numerical methods and mathematical analysis for non-spatial stochastic dynamical models that arise in molecular biology. New experimental techniques at a molecular level boosted the interest for such models in recent years, for example for gene regulatory networks, biochemical signaling and transduction cascades, molecular motors, and morphogenesis. The workshop brings together computational, mathematical, and experimental scientists, with attention falling on both current research and promising avenues for future research. It reports on the exciting synergistic interplay between advanced experimental, computational, and mathematical techniques that together provide a deeper understanding of the biological system. Speakers: John Albeck (UC Davis); Rosalind Allen (Edinburgh); Kevin Burrage (Oxford and Queensland University of Technology); Yang Cao (Virginia Tech); Simon Cotter (Manchester); Eric Deeds (Kansas); Andrew Duncan (Imperial College London); Omer Dushek (Oxford); James Faeder (Pittsburgh); Ramon Grima (Edinburgh); Ankit Gupta (ETH ); Xingye Kan (University of Minnesota); Markos Katsoulakis (University of Massachusetts); Mustafa Khammash (ETH ); Allon Klein (Harvard); Thomas Kurtz (University of Wisconsin); Carlos Lopez (Vanderbilt); Carmen Molina-Paris (University of Leeds); Jay Newby (UNC); Christian Ray (Kansas); Vahid Shahrezaei (Imperial College London); Erkki Somersal (Case Western Reserve); Vikram Sunkara (Free U. Berlin); Raul Tempone (KAUST); Pieter Rein ten Wolde (FOM Institute/Amsterdam); Thomas Vejchodsky (Institute of Mathematics at the Czech Academy of Sciences); Darren Wilkinson (Newcastle) More details and the application form are available here: https://www.newton.ac.uk/event/sdbw03 Closing date for applications: 12 February 2016 This workshop is part of a 6-month programme on "Stochastic Dynamical Systems in Biology: Numerical Methods and Applications" which is taking place at the Isaac Newton Institute (Cambridge, England) from January till June 2016. The programme will feature three workshops in Cambridge, as well as a satellite meeting in Edinburgh. More details about the whole programme can be found here: http://www.newton.ac.uk/event/sdb ------ Subject: A 2-year postdoc position From: Andrei Korobeinikov Date: Mon, 1 Feb 2016 16:29:17 +0100 The CRM welcomes applications for one 2-years postdoctoral position within the programme of Collaborative Mathematical Research. The collaborative projects proposed in this call are in one of the following groups: Complex Systems. Industrial Mathematics. Mathematical Epidemiology. Computational and Mathematic Biology. Computational Neuroscience. Financial Mathematics and Risk Control. To apply for a position, please send to crmcalls@crm.cat an email with the following information: name, personal address, email and phone number. The application package should include a CV, academic records, incorporating, if possible, the computation of the average grade and a motivation letter. A minimum of one and a maximum of three hosting CRM research groups have to be chosen, indicating preferences in the motivation letter, if any. The applicant should arrange for two referees familiar with her/his work to send a reference letter to crmcalls@crm.cat before the deadline. The deadline to submit an application is February 26, 2016 Applicants should be available for interviews (possibly via Skype) from March 7 onwards. Details and How to apply: http://www.crm.cat/en/Pages/DetallNoticia.aspx?ItemID=101 Andrei Korobeinikov Centre de Recerca Matematica Campus de Bellaterra, Edifici C 08193 Bellaterra (Barcelona) tel: +34 93 586 85 16 mobile: 65 306 79 66 http://www.crm.cat ------ Subject: Postdoc Position, Fluid Dynamics From: Shahriar Afkhami Date: January 20, 2016 Postdoctoral Position Available for September 1, 2016 Hire: Posting Number: 0603145 The Department of Mathematical Sciences at the New Jersey Institute of Technology seeks to fill a one year postdoctoral research associate position starting in the Fall of 2016 (one year renewal is possible by mutual agreement). Candidates with research focus on mathematics applied to problems in the general area of fluid dynamics are encouraged to apply. The successful applicant will be encouraged to seek collaborations with faculty members in the fluids group. Besides research, teaching one course per semester may be an option depending on individual interest and/or departmental budget. Applicants should have a Ph.D. with strong research experiences in fluid dynamics and good communication skills. At the university's discretion, the education and experience prerequisites may be excepted where the candidate can demonstrate to the satisfaction of the university, an equivalent combination of education and experience specifically preparing the candidate for success in the position. To apply, visit https://njit.jobs, posting number 0603145, and submit online (1) a cover letter, (2) a CV, and (3) a research statement. In addition, three reference letters are required. Reference letter writers should email their letters to ejallali@njit.edu. Review of applications will begin immediately and continue until the position is filled. ------ Subject: Lecturer Position, Applied Mathematics From: "Wieczorek, Sebastian" Date: Mon, 18 Jan 2016 12:51:14 +0000 Lecturer Position, Applied Mathematics, UC Cork, Ireland UCC wishes to appoint a Lecturer in Applied Mathematics. Salary Scale (in euros): 31,821 - 56,967/62,353 - 76,942. Application deadline: 02 march 2016. More details can be found at: https://www.ucc.ie/en/hr/vacancies/academic/full-details-615402-en.html ------ Subject: Contents, Discrete and Continuous Dynamical Systems - Series B 21:3 From: Liwei Ning Date: Thu, 28 Jan 2016 00:14:18 -0600 Discrete and Continuous Dynamical Systems - Series B (DCDS-B) Volume: 21, Number: 3 May 2016 http://aimsciences.org/journals/contentsListnew.jsp?pubID=833 1. A prey-predator model with migrations and delays Pages : 737 - 761 Isam Al-Darabsah, Xianhua Tang and Yuan Yuan 2. Well-posedness of the two-dimensional generalized Benjamin-Bona-Mahony equation on the upper half plane Pages : 763 - 779 C. H. Arthur Cheng, John M. Hong, Ying-Chieh Lin, Jiahong Wu and Juan-Ming Yuan 3. Global well-posedness for a fourth order pseudo-parabolic equation with memory and source terms Pages : 781 - 801 Huafei Di, Yadong Shang and Xiaoxiao Zheng 4. Coexistence equilibria of evolutionary games on graphs under deterministic imitation dynamics Pages : 803 - 813 Jeremias Epperlein, Stefan Siegmund, Petr Stehlik and Vladimir Svigler 5. On existence of wavefront solutions in mixed monotone reaction-diffusion systems Pages : 815 - 836 Wei Feng, Weihua Ruan and Xin Lu 6. A revisit to the diffusive logistic model with free boundary condition Pages : 837 - 847 Wenzhen Gan and Peng Zhou 7. Uniqueness of nonzero positive solutions of Laplacian elliptic equations arising in combustion theory Pages : 849 - 861 Kunquan Lan and Wei Lin 8. Backward bifurcation of an HTLV-I model with immune response Pages : 863 - 881 Sumei Li and Yicang Zhou 9. Existence of multiple nontrivial solutions for a p-Kirchhoff type elliptic problem involving sign-changing weight functions Pages : 883 - 908 Yuanxiao Li, Ming Mei and Kaijun Zhang 10. Dynamics in a Rosenzweig-Macarthur predator-prey system with quiescence Pages : 909 - 918 Jinfeng Wang and Hongxia Fan 11. On the uniqueness of weak solution for the 2-D Ericksen-Leslie system Pages : 919 - 941 Meng Wang, Wendong Wang and Zhifei Zhang 12. The dynamical mechanism of jets for AGN Pages : 943 - 957 Quan Wang and Huichao Wang 13. Oscillations of many interfaces in the near-shadow regime of two-component reaction-diffusion systems Pages : 959 - 975 Shuangquan Xie and Theodore Kolokolnikov 14. Global stability of a multi-group model with generalized nonlinear incidence and vaccination age Pages : 977 - 996 Jinhu Xu and Yicang Zhou 15. Analysis of a free boundary problem for avascular tumor growth with a periodic supply of nutrients Pages : 997 - 1008 Shihe Xu, Yinhui Chen and Meng Bai 16. Global stability and optimal control for a tuberculosis model with vaccination and treatment Pages : 1009 - 1022 Yali Yang, Sanyi Tang, Xiaohong Ren, Huiwen Zhao and Chenping Guo 17. Errata: Evolutionary dynamics of a multi-trait semelparous model Pages : 1023 - 1026 Amy Veprauskas and J. M. Cushing ------ Subject: Contents, Journal of Dynamics and Games 2:3-4 From: Liwei Ning Date: Wed, 27 Jan 2016 23:55:48 -0600 Journal of Dynamics and Games (JDG) Volume: 2, Number: 3&4 July&October 2015 http://aimsciences.org/journals/contentsListnew.jsp?pubID=822 1. Preface Pages : i - i Alberto Adrego Pinto and Michel Bena?m 2. On Marilda Sotomayor's extraordinary contribution to matching theory Pages : 201 - 206 Danilo Coelho and David Perez-Castrillo 3. Endogenous budget constraints in the assignment game Pages : 207 - 225 David Cantala and Juan Sebastian Pereyra 4. A survey on assignment markets Pages : 227 - 256 Marina Nunez and Carles Rafels 5. Paths to stability in the assignment problem Pages : 257 - 287 Bettina Klaus and Frederic Payot 6. A deferred acceptance algorithm with contracts Pages : 289 - 302 Eliana Pepa Risma 7. Externality effects in the formation of societies Pages : 303 - 320 Renato Soeiro, Abdelrahim Mousa and Alberto A. Pinto 8. Finding all stable matchings with couples Pages : 321 - 330 Fuhito Kojima 9. Why do stable clearinghouses work so well? - Small sets of stable matchings in typical environments, and the limits-on-manipulation theorem of Demange, Gale and Sotomayor Pages : 331 - 340 Alvin E. Roth 10. Dynamic club formation with coordination Pages : 341 - 361 Tone Arnold and Myrna Wooders 11. For claims problems, another compromise between the proportional and constrained equal awards rules Pages : 363 - 382 William Thomson ------ Subject: Contents, Communications on Pure and Applied Analysis 15:2 From: Liwei Ning Date: Thu, 28 Jan 2016 00:27:17 -0600 Communications on Pure and Applied Analysis (CPAA) Volume: 15, Number: 2 March 2016 http://aimsciences.org/journals/contentsListnew.jsp?pubID=832 1. On the nonlocal Cahn-Hilliard-Brinkman and Cahn-Hilliard-Hele-Shaw systems Pages : 299 - 317 Francesco Della Porta and Maurizio Grasselli 2. Traveling wave solutions of a reaction-diffusion equation with state-dependent delay Pages : 319 - 334 Guo Lin and Haiyan Wang 3. Remarks on weak solutions of fractional elliptic equations Pages : 335 - 340 Wanwan Wang, Hongxia Zhang and Huyuan Chen 4. The stability of nonlinear Schr?dinger equations with a potential in high Sobolev norms revisited Pages : 341 - 365 Myeongju Chae and Soonsik Kwon 5. Optimal Szego-Weinberger type inequalities Pages : 367 - 383 Friedemann Brock, Francesco Chiacchio and Giuseppina di Blasio 6. Existence and nonexistence of positive solutions to an integral system involving Wolff potential Pages : 385 - 398 Wu Chen and Zhongxue Lu 7. Boundary value problems for a semilinear elliptic equation with singular nonlinearity Pages : 399 - 412 Zongming Guo and Yunting Yu 8. Multi-bump positive solutions of a fractional nonlinear Schrodinger equation in R^N Pages : 413 - 428 Weiming Liu and Lu Gan 9. Schrodinger-Kirchhoff-Poisson type systems Pages : 429 - 444 Cyril Joel Batkam and Joao R. Santos Junior 10. Positive solution for the Kirchhoff-type equations involving general subcritical growth Pages : 445 - 455 Jiu Liu, Jia-Feng Liao and Chun-Lei Tang 11. Competing interactions and traveling wave solutions in lattice differential equations Pages : 457 - 475 E. S. Van Vleck and Aijun Zhang 12. One dimensional p-th power Newtonian fluid with temperature-dependent thermal conductivity Pages : 477 - 494 Tao Wang 13. Reaction-Diffusion equations with spatially variable exponents and large diffusion Pages : 495 - 506 Jacson Simsen, Mariza Stefanello Simsen and Marcos Roberto Teixeira Primo 14. Local regularity of the magnetohydrodynamics equations near the curved boundary Pages : 507 - 517 Jae-Myoung Kim 15. Uniqueness of solutions for elliptic systems and fourth order equations involving a parameter Pages : 519 - 533 Craig Cowan 16. Existence and concentration of solutions for a non-linear fractional Schrodinger equation with steep potential well Pages : 535 - 547 Cesar E. Torres Ledesma 17. Elliptic systems with boundary blow-up: existence, uniqueness and applications to removability of singularities Pages : 549 - 562 Jorge Garcia-Melian, Julio D. Rossi and Jose C. Sabina de Lis 18. Concentration of solutions for the fractional Nirenberg problem Pages : 563 - 576 Zhongyuan Liu 19. Center problem for systems with two monomial nonlinearities Pages : 577 - 598 Armengol Gasull, Jaume Gine and Joan Torregrosa 20. Existence and concentration of semiclassical solutions for Hamiltonian elliptic system Pages : 599 - 622 Jian Zhang, Wen Zhang and Xiaoliang Xie 21. Non-sharp travelling waves for a dual porous medium equation Pages : 623 - 636 Jing Li, Yifu Wang and Jingxue Yin 22. Asymptotic analysis of a spatially and size-structured population model with delayed birth process Pages : 637 - 655 Dongxue Yan and Xianlong Fu 23. Some observations on the Green function for the ball in the fractional Laplace framework Pages : 657 - 699 Claudia Bucur