一、报告人：
Dr. Alessandro Hill(assistant professor in industrial engineering at California Polytechnic State University)
二、摘要：
We propose two novel variants of the well-known Steiner tree problem in graphs that are motivated by applications in secure strategic telecommunication network design. Both network optimization models ask for a tree of minimal total edge cost that connects a pre-specified set of terminal nodes to a dedicated root node by optionally including intermediate Steiner nodes. Two types of privacy conflicts between pairs of conflicting terminals are considered: (I) The path from the root to a terminal must not include the conflicting terminal, and (II) conflicting terminals have to be on separate branches of the tree. We develop non-compact integer programming formulations and elaborate branch-and-cut algorithms. We incorporate problem specific valid inequalities that are crucial in order to solve these problems, and establish dominance relationships between these cuts and the induced polyhedra. The effectiveness of the cutting planes with respect to the dual bound and the performance of the exact algorithm are assessed on a diverse set of SteinLib-based test instances. Moreover, we present results from constraint programming based approaches and custom-tailored heuristics.
三、地点和时间：
机械工程学院 机械楼D530 2019年7月25日早上9:00-11:00
四、报告人简介：
Dr. Alessandro Hill is currently an assistant professor in industrial engineering at California Polytechnic State University. He studied mathematics and computer science at University of Augsburg (Germany) and Iowa State University (USA), and obtained his Ph.D. in Operations Research from the University of Hamburg (Germany). In several research and industry projects he worked for industries such as automotive, railroads, telecommunications, logistics and chemicals with a focus on optimization, simulation and analytics to provide decision support. His main research areas are optimization methods and applications for networks and scheduling.
