CEM Software-Verification and Validation of Computational EM Software (original) (raw)
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CEM Validation-VERIFICATION AND VALIDATION OF COMPUTATIONAL ELECTROMAGNETICS SOFTWARE
One of the most time-consuming tasks associated with developing and using computer models in electromagnetics is that of verifying software performance and validating the model results. Even now, relatively few available modeling packages offer the user substantial on-line assistance concerning verification and validation. This paper discusses the kinds of errors that most commonly occur in modeling, the need for quantitative error measures, and various validation tests such as convergence behavior and bounary-condition checks. Use of model-based parameter estimation to develop error estimates or to control uncertainty in an observable is demonstrate several examples. The article concludes by recommending that the Computational Electro-Magnetics community adopt a policy of requiring some minimal standards concerning the accuracy of numerical results accepted for journal articles and meeting presentations.
Computations have become a tool coequal with mathematics and measurements as a means of performing electromagnetic analysis and design. This is attested to by the volume of articles and meeting presentations in which computational electromagnetics (CEM) is routinely employed to address an increasing variety of problems. Yet, in spite of the substantial resources invested in CEM software over the past three decades, little real progress seems to have been made towards providing the EM engineer software tools having a functionality equivalent to that expected of experimental hardware. Furthermore, the bulk of CEM software now available is generally of limited applicability to large, complex problems because most modeling codes employ a single field propagator, or analytical form, of Maxwell's Equations. The acknowledged advantages of hybrid models, those which employ different propagators in differing regions of a problem, are relatively unexploited.
CEM-A Selective Survey of Computational Electromagnetics
The continuing growth of computing resources is changing how we think about, formulate, solve, and interpret problems. In electromagnetics, as elsewhere, computational techniques are complementing the more traditional approaches of measurement and analysis to expand vastly the breadth and depth of problems that are now quantifiable. An attempt is made to place into perspective some of the tools used in computational electromagnetics with respect to the different kinds of approaches that may be used and their computer-resource requirements, paying particular attention to numerical models based on integral and differential equations. After a brief background discussion, some of the analytical and numerical issues involved in developing a computer model are reviewed. Some practical considerations are included from the viewpoint of computer-resource requirements, followed by a discussion of some ways by which computer time might be reduced. The presentation concludes with a brief examination of validation and error checking. The emphasis throughout is on review and summarization rather than detailed exposition.
Validation, verification and calibration in applied computational electromagnetics
2010
Model validation, data verification, and code calibration (VV&C) in applied computational electromagnetics is discussed. The step by step VV&C procedure is given systematically through canonical scenarios and examples. Propagation over flat-Earth with linearly decreasing vertical refractivity profile, having an analytical exact solution, is taken into account as the real-life problem. The parabolic wave equation (PWE) is considered as the mathematical model. MatLab-based numerical simulators for both the split step Fourier and finite element implementations of the PWE are developed. The simulators are calibrated against analytical exact and high frequency asymptotic solutions. Problems related to the generation of reference data during accurate numerical computations are presented.
CEM SOFTWARE: CHARACTERIZATION, COMPARISON, AND VALIDATION OF ELECTROMAGNETIC MODELING SOFTWARE.pdf
The continuously increasing number of electromagnetic computer models (codes) and applications thereof is one result of a rapidly expanding computing resource base of exponentially growing capability. While the growing use of computers in electromagnetics attests to the value of computer modeling for solving problems of practical interest, the proliferation of codes and results being produced increases the need for their validation with respect to both electromagnetic formulation and software implementation. But validation is perhaps the most difficult step in code development, especially for those models intended for general-purpose application where they may be used in unpredictable or inappropriate ways. A procedure or protocol for validating codes both internally, where necessary but not always sufficient checks of a valid computation can be made, and externally, where independent results are used for this purpose, is needed. Ways of comparing differing computer models with respect to their efficiency and utility to make more relevant intercode comparisons and thereby provide a basis for code selection by users having particular problems to model are also needed. These issues are discussed in this article and some proposals are presented for characterizing, comparing, and validating EM modeling codes in ways most relevant to the end user.
CEM Software-The Numerical Electromagnetics Code (NEC)
This document was prepared as an account of work sponsored by an agency of the United States Government. Neither tk United States Government nor the University of California nor any of their empfo~makes SWY warrenty, express or impfiad, or assumes any iegsl Iiibility or responsibility for the wmrraex compfetenesai or rrsefainess of any inforrrratiomappsra~prodrx%or process discfosad, or reiwesents that its use would rmt infringe privately owned rights. Referense herein to any spe.cifk commercial prodnc@ pr~or servfee by trsde name, trademark, mamrfscturer, or otherwise, does not neceasariiy eonstitwte or imply its ewdomemerrt recomwtesrdatiorh or favoring by the United States Government or the University of California. The views and opinions of authore expressed herein do not necessarily state or reflect those of tbe United States Government or tbe University of Cafifomi& and shafi not be used for advertising or product endorsement purposes.
Applied Computational Electromagnetics Society Journal. Volume 13, No. 1
1998
The Applied Computational Electromagnetics Society Journal hereinafter known as the ACES Journal is devoted to the exchange of information in computational electromagnetics, to the advancement of the state-of-the-art, and to the promotion of related technical activities. A primary objective of the information exchange is the elimination of the need to "re-invent the wheel" to solve a previously-solved computational problem in electrical engineering, physics, or related fields of study. The technical activities promoted by this publication include code validation, performance analysis, and input/output standardization; code or technique optimization and error minimization; innovations in solution technique or in data input/output; identification of new applications for electromagnetics modeling codes and techniques; integration of computational electromagnetics techniques with new computer architectures; and correlation of computational parameters with physical mechanisms.
A Selective Survey of Computational Electromagnetics
The continuing growth of computing resources is changing how we think about, formulate, solve, and interpret problems. In electromagnetics, as elsewhere, computational techniques are complementing the more traditional approaches of measurement and analysis to expand vastly the breadth and depth of problems that are now quantifiable. An attempt is made to place into perspective some of the tools used in computational electromagnetics with respect to the different kinds of approaches that may be used and their computer-resource requirements, paying particular attention to numerical models based on integral and differential equations. After a brief background discussion, some of the analytical and numerical issues involved in developing a computer model are reviewed. Some practical considerations are included from the viewpoint of computer-resource requirements, followed by a discussion of some ways by which computer time might be reduced. The presentation concludes with a brief examination of validation and error checking. The emphasis throughout is on review and summarization rather than detailed exposition.
CEM-Computational Electromagnetics.pdf
We briefly consider here a classification of model types, the steps involved in developing a computer model , the desirable attributes of a computer model, and finally the role of approximation throughout the modeling process.