学　术

　　人力资源部教师发展中心举办“学者论坛”系列学术活动，定期邀请与我校教师研究领域相关的知名学者，以专题报告的形式与师生分享和研讨最新研究动态和成果，旨在为教师提供学术探讨和交流的平台，开拓教师学术视野。现将第30期论坛安排如下，欢迎广大师生参加。

　　一、主　题：

　　Explicit Time-Domain Methods that are Unconditionally Stable

　　二、主讲人：

　　Prof. Dan Jiao,School of Electrical and Computer Engineering, Purdue University

　　三、时　间：

　　2016年8月1日（周一）9:30

　　四、地　点：

　　清水河校区科研楼C218会议室

　　五、主持人：

　　胡俊 教授

　　六、内容简介

　　Time-domain computational electromagnetic (CEM) methods have suffered from a long-lasting bottleneck problem. This problem is well-known as the dependence of the time step on the smallest space step for ensuring the stability of an explicit-method based time-domain simulation, such as the Courant-Friedrichs-Lewy (CFL) condition required by an explicit FDTD method. Because of this dependence, when the structure being simulated involves fine features relative to the working wavelength, a tremendous number of time steps are required to finish one simulation, which is computationally expensive. Existing unconditionally stable methods are all implicit methods. Unlike explicit methods that avoid solving a matrix equation, an implicit method requires a matrix solution, and hence becoming computationally expensive when the matrix size is large.

　　In this work, we present explicit time-domain methods that are unconditionally stable, a class of methods that did not exist prior to this work. In the proposed methods, we quantitatively identified the root cause of the instability associated with an explicit time domain method. With the identification of the root cause, we successfully created both an unconditionally stable explicit TDFEM method and an unconditionally stable explicit FDTD method. These explicit methods are stable for an arbitrarily large time step irrespective of space step, and accurate for a time step solely determined by accuracy. The proposed methods retain the strength of an explicit time-domain method in avoiding solving a matrix equation while eliminating their shortcoming in time step when space step is small. Numerical experiments have demonstrated their superior performance in computational efficiency as well as stability compared with the conditionally stable explicit method and the unconditionally stable implicit method. In addition to the FDTD and the TDFEM methods, the essential idea of the presented work for making an explicit method stable for an arbitrarily large time step irrespective of space step is also applicable to other time domain methods.

　　七、主讲人简介

　　Prof. Dan Jiao received her Ph.D. degree in Electrical Engineering from the University of Illinois at Urbana-Champaign in October 2001. She then worked at the Technology CAD (Computer-Aided-Design) Division at the Intel Corporation until September 2005 as Senior Engineer, Staff Engineer, and Senior Staff Engineer. In September 2005, she joined Purdue University as an Assistant Professor in the School of Electrical and Computer Engineering, where she was promoted to a tenured Associate Professor in 2009, and a Full Professor in 2013. She has authored over 240 papers in refereed journals and international conferences. Prof. Jiao has received numerous awards including the 2000 Raj Mittra Outstanding Research Award, the 2004 Best Paper Award from Intel’s annual technology conference (Design and Test Technology Conference), the 2008 National Science Foundation CAREER Award, the 2010 Ruth and Joel Spira Outstanding Teaching Award, one of the 85 engineers selected throughout the US for the National Academy of Engineering’s 2011 US Frontiers of Engineering Symposium, the 2013 Sergei A. Schelkunoff Best Paper Award of the IEEE Antennas and Propagation Society, and being one of the 21 faculty selected across US as the 2014-2015 Fellow of ELATE, a national leadership program for women in the academic STEM fields. Prof. Jiao has served on a number of Technical Program Committees of premium conferences in electromagnetics, microwave, and circuits. She has been an Associated Editor of the IEEE Transactions on Components, Packaging and Manufacturing Technology, and a board member of IET Circuits, Devices & Systems. She is a Fellow of IEEE.

　　八、主办单位：人力资源部教师发展中心

　　　　承办单位：电子工程学院

　　欢迎广大老师和同学参加！

　　　　　　　　　　　　　　　　　　　　　人力资源部教师发展中心

　　　　　　　　　　　　　　　　　　　　　　　2016年7月29日