Conferința lunară a FMI:
Marti, 16.05.2023, ora 16, în sala 214 (sala Google), vom avea 2 invitați din străinătate:
Prof. Mehmet Yavuz (Necmettin Erbakan University) și
Prof. Gruia Călinescu (Illinois Institute of Technology)
care vor susține următoarele prelegeri:
– ora 16:00 Mehmet Yavuz: Mathematical Modelling in Real-Life Problems: A Fractional-Order Approach
– ora 17:00 Gruia Călinescu: Combination algorithms for Steiner Tree variants
Rezumat prezentare Mehmet Yavuz: „In this talk, new perspectives on the recent theoretical developments in mathematical modelling and its illustrative applications/analysis in science, engineering, biology, and health sciences are presented. Mathematical modelling and simulation in real- life problems and their applications in terms of both theoretical and biological/physical/ecological points of view arise in a number of research problems ranging from physical and chemical processes to biomathematics and life science. As known, the modeling of a biological compartmental system requires the analysis of the different interactions occurring among the different components of the system. Determining the suitable parameters for the system is also a critical process. Moreover, considering the effects of fractional calculus on the mentioned systems provides a new perspective and helps scientists take advantage of it in modelling and interpretations.”
Rezumat prezentare Gruia Călinescu: „We give better approximation ratios for two Steiner Tree variants by combining known algorithms: the almost optimum 3-restricted decomposition and iterative randomized rounding. The first problem is Steiner Tree with minimum number of Steiner Points and bounded edged length problem (SMT-MSP). The input consists of a set of terminals T in Euclidean space R^2. A feasible solution is a Steiner tree spanning T with Steiner points S such that every edge in this tree has length at most 1. And the objective is to minimize the cardinality of S. Previous, the best approximation ratio for SMT-MSP was 2.386. We present a polynomial time algorithm with ratio 2.277. The second problem is minimum Steiner Tree in quasi-bipartite graphs. It is a minimum Steiner Tree problem on graph G=(V,E,c) with terminal set T. And the edge set does not include any edge between two vertices not in T. The best-known approximation ratio for this problem is 73/60. We improve this ratio to 298/245. (Joint work with Xiaolang Wang)”