Abstract

For the past several decades, a computing-resource of exponentially expanding capability now called computational electromagnetics (CEM) has grown into a tool that both complements and relies on measurement and analysis for its development and validation, The growth of CEM is demonstrated by the number of computer models (codes) available and the complexity of problems being solved attesting to its utility and value. Even now, however, relatively few available modeling packages offer the user substantial on-line assistance concerning verification and validation. CEM would be of even greater practical value were the verification and validation of the codes and the results they produce more convenient. Verification means determining that a code conforms to the analytical foundation and numerical implementation on which it is based. Validation means determining the degree to which results produced by the code conform to physical reality. Validation is perhaps the most challenging aspect of code development especially for those intended for general-purpose application where inexperienced users may employ the codes in unpredictable or inappropriate ways. This presentation discusses some of the errors, both numerical and physical, that most commonly occur in modeling, the need for quantitative error measures, and various validation tests that can be used. A procedure or protocol for validating codes both internally and externally is proposed.  Ways of comparing different computer models with respect not only to their efficiency and utility, but also to make more relevant intercode comparisons and to thereby provide a basis for code selection by users having particular problems to model, are also discussed. The kinds of information that can be realistically expected from a computer model and how and why the computed results might differ from physical reality are considered.A procedure called “Feature Selective Validation” that has received increasing attention in the Electromagnetic Compatibility Community as a means of comparing data sets will be summarized. The overall goal is to characterize, compare, and validate EM modeling codes in ways most relevant to the end user.

Biography

Since earning his PhD in Electrical Engineering at the University of Michigan, E. K. Miller has held a variety of government, academic and industrial positions.  These include 15 years at Lawrence Livermore National Laboratory where he spent 7 years as a Division Leader, and 4+ years at Los Alamos National Laboratory from which he retired as a Group Leader in 1993.  His academic experience includes holding a position as Regents-Distinguished Professor at Kansas University and as Stocker Visiting Professor at Ohio University.  Dr. Miller wrote the column “PCs for AP and Other EM Reflections” for the AP-S Magazine from 1984 to 2000.  He received (with others) a Certificate of Achievement from the IEEE Electromagnetic Compatibility Society for Contributions to Development of NEC (Numerical Electromagnetics Code) and was a recipient (with others) in 1989 of the best paper award given by the Education Society for “Computer Movies for Education.” Dr. Miller edited the book “Time-Domain Measurements in Electromagnetics”, Van Nostrand Reinhold, New York, NY, 1986 and was co-editor of the IEEE Press book Computational Electromagnetics:  Frequency-Domain Moment Methods, 1991.  He was organizer and first President of the Applied Computational Electromagnetics Society (ACES) for which he also served two terms on the Board of Directors.  He served a term as Chairman of Commission A of US URSI and is or has been a member of Commissions B, C, and F, has been on the TPC for the URSI Electromagnetic Theory Symposia in 1992 and 2001, and was elected as a member of the US delegation to several URSI General Assemblies.  He is a Life Fellow of IEEE from which he received the IEEE Third Millennium Medal in 2000 and is a Fellow of ACES.  His research interests include scientific visualization, model-based parameter estimation, the physics of electromagnetic radiation, validation of computational software, and numerical modeling about which he has published more than 150 articles and book chapters.  He is listed in Who’s Who in the West, Who’s Who in Technology, American Men and Women of Science and Who’s Who in America.