Download or read book Numerical Errors and Accuracy efficiency Tradeoff in Frequency and Time domain Integral Equation Solvers written by Guneet Kaur and published by . This book was released on 2010 with total page 86 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis presents a detailed study of the numerical errors and the associated accuracy-efficiency tradeoffs encountered in the solution of frequency- and time-domain integral equations. For frequency-domain integral equations, the potential integrals contain singular Green's function kernels and the resulting singular and near-singular integrals must be carefully evaluated, using singularity extraction or cancellation techniques, to ensure the accuracy of the method-of-moments impedance matrix elements. This thesis presents a practical approach based on the progressive Gauss-Patterson quadrature rules for implementing the radial-angular-transform singularity-cancellation method such that all singular and near-singular integrals are evaluated to an arbitrary pre-specified accuracy. Numerical results for various scattering problems in the high- and low-frequency regimes are presented to quantify the efficiency of the method and contrast it to the singularity extraction method. For time-domain integral equations, the singular Green's function kernels are functions of space and time and sub-domain temporal basis functions rather than entire-domain sinusoidal/Fourier basis functions are used to represent the time variation of currents/fields. This thesis also investigates the accuracy-efficiency tradeoff encountered when choosing sub-domain temporal basis functions by contrasting two prototypical ones: The causal piecewise polynomial interpolatory functions, sometimes called shifted Lagrange interpolants, and the band-limited interpolatory functions based on approximate prolate spheroidal wave functions. It is observed that the former is more efficient for low to moderate accuracy levels and the latter achieves higher, but extrapolation-limited, accuracy levels.
Download or read book Envelope tracking Integral Equation Methods for Band pass Transient Scattering Analysis written by Guneet Kaur and published by . This book was released on 2015 with total page 282 pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation presents envelope-tracking (ET) integral equation methods to efficiently analyze band-pass scattering problems. Unlike the traditional time-domain marching-on-in-time (TD-MOT) schemes, ET-MOT schemes solve for space-time samples of not the current density but its complex envelope. The time step size used in ET-MOT schemes is inversely proportional to the bandwidth of the fields of interest and not their maximum frequency content; thus, ET-MOT schemes can use (much) larger time step sizes for band-pass analysis: the smaller the bandwidth of the fields compared to their maximum frequency content, the larger the time step size in ET-MOT solutions compared to those in the TD-MOT solutions. Despite the reduction in the number of time steps, ET-MOT schemes suffer from high computational costs that also affect time- and frequency-domain integral equation methods. This dissertation presents an FFT-based algorithm, the ET adaptive integral method (ET-AIM), to reduce the computational complexity of ET-MOT schemes. ET-AIM is both theoretically and empirically compared to its time-domain and frequency-domain counterparts, TD-AIM and FD-AIM, respectively. Because the performance of the envelope-tracking methods is a complex function of the bandwidth of interest and because each method has different accuracy-efficiency tradeoff, only limited deductions can be made from theoretical comparison of the methods. Thus, in addition to theoretical comparisons, an empirical approach for comparing the different methods is presented: To perform a fair, meaningful, and generalizable comparison, benchmark problems are identified, an appropriate error norm is defined, and the key parameters of the methods are optimized subject to a constraint on the error norm. Computational costs are measured and compared for all three methods for solving progressively larger benchmark scattering problems for varying frequency bandwidths. This dissertation also proposes an out-of-core algorithm to ameliorate the high memory requirement of FFT-accelerated time-marching methods. The proposed algorithm exchanges the core memory requirement with external storage space requirement without significantly increasing the simulation time. The performance of the proposed methods is demonstrated by solving surface- and volume-integral equations pertinent to scattering problems that involve good conductors and inhomogeneous volumes with complex dielectric properties. For example, numerical results obtained using ET-AIM are presented for analysis of scattering of radar pulses from a PEC missile, a generic aircraft, etc. and antenna radiation near anatomically realistic human body model.
Download or read book Time Domain Boundary Integral Equations Analysis written by Amir Geranmayeh and published by Sudwestdeutscher Verlag Fur Hochschulschriften AG. This book was released on 2011-01 with total page 208 pages. Available in PDF, EPUB and Kindle. Book excerpt: The present research study mainly involves a survey of diverse time-domain boundary element methods that can be used to numerically solve the retarded potential integral equations. The aim is to address the late-time stability, accuracy, and computational complexity concerns in time-domain surface integral equation approaches. The study generally targets the transient electromagnetic scattering of three- dimensional perfectly conducting bodies. Efficient algorithms are developed to numerically solve the electric, magnetic, and combined field integral equations for the unknown induced surface current. The algorithms are mainly categorized into three major discretization schemes, namely the marching-on- in-time, the marching-on-in-order, and the convolution quadrature methods or finite difference delay modeling. Possible choices of space-time integration are examined and the results are compared with the finite integration technique's solution. The outcome is applied to the non- dispersive modeling of the field propagation in particle accelerator structures, when travelling bunches of charged particles passes through the beam line elements.
Download or read book Inverse Methods in Action written by Pierre C. Sabatier and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 645 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume contains the Proceedings of a meeting held at Montpellier from November 27th to December 1st 1989 and entitled "Inverse Problems Multicen tennials Meeting". It was held in honor of two major centennials: the foundation of Montpellier University in 1289 and the French Revolution of 1789. The meet ing was one of a series of annual meetings on interdisciplinary aspects of inverse problems organized in Montpellier since 1972 and known as "RCP 264". The meeting was sponsored by the Centre National de la Recherche Scientifique (con tract GR 264) and by the Direction des Recherches et Etudes Techniques (contract 88 CO 283). The Proceedings are presented by chapters on different topics, the choice of topic often being arbitrary. The chapter titles are "Tomographic Inverse Problems", "Distributed Parameters Inverse Problems", "Spectral Inverse Problems (Exact Methods)", "Theoretical hnaging", "Wave Propagation and Scattering Problems (hnaging and Numerical Methods)", "Miscellaneous Problems", "Inverse Methods and Applications to Nonlinear Problems". In each chapter but the first, the papers have been sorted alphabetically according to author*. In the first chapter, a set of theoretical papers is presented first, then more applied ones. There are so many well-known and excellent lectures that I will not try to refer to them all here (the reader will be easily convinced by reading the Table of Contents). My comments at the conference are summarized by the short scientific introduction at the beginning of the volume.
Download or read book Electrical Electronics Abstracts written by and published by . This book was released on 1997 with total page 2240 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Applied Mechanics Reviews written by and published by . This book was released on 1993 with total page 768 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Numerical Techniques in Acoustic Radiation written by American Society of Mechanical Engineers. Winter Annual Meeting and published by . This book was released on 1989 with total page 196 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book OAR written by and published by . This book was released on 1967 with total page 570 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Physics Briefs written by and published by . This book was released on 1991 with total page 888 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Air Force Research Resum s written by and published by . This book was released on with total page 572 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Numerical Algorithms written by Justin Solomon and published by A K PETERS. This book was released on 2020-06-30 with total page 400 pages. Available in PDF, EPUB and Kindle. Book excerpt: Numerical Algorithms: Methods for Computer Vision, Machine Learning, and Graphics presents a new approach to numerical analysis for modern computer scientists. Using examples from a broad base of computational tasks, including data processing, computational photography, and animation, the textbook introduces numerical modeling and algorithmic design from a practical standpoint and provides insight into the theoretical tools needed to support these skills. The book covers a wide range of topics--from numerical linear algebra to optimization and differential equations--focusing on real-world motivation and unifying themes. It incorporates cases from computer science research and practice, accompanied by highlights from in-depth literature on each subtopic. Comprehensive end-of-chapter exercises encourage critical thinking and build students' intuition while introducing extensions of the basic material. The text is designed for advanced undergraduate and beginning graduate students in computer science and related fields with experience in calculus and linear algebra. For students with a background in discrete mathematics, the book includes some reminders of relevant continuous mathematical background.
Download or read book Electromagnetic Shielding written by Salvatore Celozzi and published by John Wiley & Sons. This book was released on 2022-12-28 with total page 564 pages. Available in PDF, EPUB and Kindle. Book excerpt: Comprehensive Resource for Understanding Electromagnetic Shielding Concepts and Recent Developments in the Field This book describes the fundamental, theoretical, and practical aspects to approach electromagnetic shielding with a problem-solving mind, either at a design stage or in the context of an issue-fixing analysis of an existing configuration. It examines the main shielding mechanisms and how to analyze any shielding configuration, taking into account all the involved aspects. A detailed discussion on the possible choices of parameters suitable to ascertain the performance of a given shielding structure is also presented by considering either a continuous wave EM field source or a transient one. To aid in reader comprehension, both a theoretical and a practical engineering point of view are presented with several examples and applications included at the end of main chapters. Sample topics discussed in the book include: Concepts in transient shielding including performance parameters and canonical configurations Time domain performance of shielding structures, thin shields, and overall performance of shielding enclosures (cavities) How to install adequate barriers around the most sensitive components/systems to reduce or eliminate interference Details on solving core fundamental issues for electronic and telecommunications systems via electromagnetic shielding For industrial researchers, telecommunications/electrical engineers, and academics studying the design of EM shielding structures, this book serves as an important resource for understanding both the logistics and practical applications of electromagnetic shielding. It also includes all recent developments in the field to help professionals stay ahead of the curve in their respective disciplines.
Download or read book Dissertation Abstracts International written by and published by . This book was released on 2008 with total page 994 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Computer Modeling in Engineering Sciences written by and published by . This book was released on 2004 with total page 232 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Numerical Solution of Ordinary Differential Equations written by Kendall Atkinson and published by John Wiley & Sons. This book was released on 2011-10-24 with total page 272 pages. Available in PDF, EPUB and Kindle. Book excerpt: A concise introduction to numerical methodsand the mathematicalframework neededto understand their performance Numerical Solution of Ordinary Differential Equationspresents a complete and easy-to-follow introduction to classicaltopics in the numerical solution of ordinary differentialequations. The book's approach not only explains the presentedmathematics, but also helps readers understand how these numericalmethods are used to solve real-world problems. Unifying perspectives are provided throughout the text, bringingtogether and categorizing different types of problems in order tohelp readers comprehend the applications of ordinary differentialequations. In addition, the authors' collective academic experienceensures a coherent and accessible discussion of key topics,including: Euler's method Taylor and Runge-Kutta methods General error analysis for multi-step methods Stiff differential equations Differential algebraic equations Two-point boundary value problems Volterra integral equations Each chapter features problem sets that enable readers to testand build their knowledge of the presented methods, and a relatedWeb site features MATLAB® programs that facilitate theexploration of numerical methods in greater depth. Detailedreferences outline additional literature on both analytical andnumerical aspects of ordinary differential equations for furtherexploration of individual topics. Numerical Solution of Ordinary Differential Equations isan excellent textbook for courses on the numerical solution ofdifferential equations at the upper-undergraduate and beginninggraduate levels. It also serves as a valuable reference forresearchers in the fields of mathematics and engineering.
Download or read book International Aerospace Abstracts written by and published by . This book was released on 1999 with total page 1032 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Numerical Methods for Fluid Dynamics written by Dale R. Durran and published by Springer Science & Business Media. This book was released on 2010-09-14 with total page 527 pages. Available in PDF, EPUB and Kindle. Book excerpt: This scholarly text provides an introduction to the numerical methods used to model partial differential equations, with focus on atmospheric and oceanic flows. The book covers both the essentials of building a numerical model and the more sophisticated techniques that are now available. Finite difference methods, spectral methods, finite element method, flux-corrected methods and TVC schemes are all discussed. Throughout, the author keeps to a middle ground between the theorem-proof formalism of a mathematical text and the highly empirical approach found in some engineering publications. The book establishes a concrete link between theory and practice using an extensive range of test problems to illustrate the theoretically derived properties of various methods. From the reviews: "...the books unquestionable advantage is the clarity and simplicity in presenting virtually all basic ideas and methods of numerical analysis currently actively used in geophysical fluid dynamics." Physics of Atmosphere and Ocean
