327 results on '"Numerical analysis."'
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102. Spectral and High Order Methods for Partial Differential Equations ICOSAHOM 2014 : Selected papers from the ICOSAHOM conference, June 23-27, 2014, Salt Lake City, Utah, USA / edited by Robert M. Kirby, Martin Berzins, Jan S. Hesthaven.
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Kirby, Robert M. editor., Berzins, Martin. editor., Hesthaven, Jan S. editor., SpringerLink (Online service), Kirby, Robert M. editor., Berzins, Martin. editor., Hesthaven, Jan S. editor., and SpringerLink (Online service)
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The book contains a selection of high quality papers, chosen among the best presentations during the International Conference on Spectral and High-Order Methods (2014), and provides an overview of the depth and breadth of the activities within this important research area. The carefully reviewed selection of papers will provide the reader with a snapshot of the state-of-the-art and help initiate new research directions through the extensive biography.
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- 2015
103. Error Estimates for Well-Balanced Schemes on Simple Balance Laws : One-Dimensional Position-Dependent Models / by Debora Amadori, Laurent Gosse.
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Amadori, Debora. author., Gosse, Laurent. author., SpringerLink (Online service), Amadori, Debora. author., Gosse, Laurent. author., and SpringerLink (Online service)
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- 2015
104. Introduction to Uncertainty Quantification / by T.J. Sullivan.
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Sullivan, T.J. author., SpringerLink (Online service), Sullivan, T.J. author., and SpringerLink (Online service)
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Uncertainty quantification is a topic of increasing practical importance at the intersection of applied mathematics, statistics, computation, and numerous application areas in science and engineering. This text provides a framework in which the main objectives of the field of uncertainty quantification are defined, and an overview of the range of mathematical methods by which they can be achieved. Complete with exercises throughout, the book will equip readers with both theoretical understanding and practical experience of the key mathematical and algorithmic tools underlying the treatment of uncertainty in modern applied mathematics. Students and readers alike are encouraged to apply the mathematical methods discussed in this book to their own favourite problems to understand their strengths and weaknesses, also making the text suitable as a self-study. This text is designed as an introduction to uncertainty quantification for senior undergraduate and graduate students with a mathematical or statistical background, and also for researchers from the mathematical sciences or from applications areas who are interested in the field. T. J. Sullivan was Warwick Zeeman Lecturer at the Mathematics Institute of the University of Warwick, United Kingdom, from 2012 to 2015. Since 2015, he is Junior Professor of Applied Mathematics at the Free University of Berlin, Germany, with specialism in Uncertainty and Risk Quantification.
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- 2015
105. Numerical Analysis and Optimization : NAO-III, Muscat, Oman, January 2014 / edited by Mehiddin Al-Baali, Lucio Grandinetti, Anton Purnama.
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Al-Baali, Mehiddin. editor., Grandinetti, Lucio. editor., Purnama, Anton. editor., SpringerLink (Online service), Al-Baali, Mehiddin. editor., Grandinetti, Lucio. editor., Purnama, Anton. editor., and SpringerLink (Online service)
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Presenting the latest findings in the field of numerical analysis and optimization, this volume balances pure research with practical applications of the subject. Accompanied by detailed tables, figures, and examinations of useful software tools, this volume will equip the reader to perform detailed and layered analysis of complex datasets. Many real-world complex problems can be formulated as optimization tasks. Such problems can be characterized as large scale, unconstrained, constrained, non-convex, non-differentiable, and discontinuous, and therefore require adequate computational methods, algorithms, and software tools. These same tools are often employed by researchers working in current IT hot topics such as big data, optimization and other complex numerical algorithms on the cloud, devising special techniques for supercomputing systems. The list of topics covered include, but are not limited to: numerical analysis, numerical optimization, numerical linear algebra, numerical differential equations, optimal control, approximation theory, applied mathematics, algorithms and software developments, derivative free optimization methods and programming models. The volume also examines challenging applications to various types of computational optimization methods which usually occur in statistics, econometrics, finance, physics, medicine, biology, engineering and industrial sciences.
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- 2015
106. Fundamentals of Adaptive Signal Processing / by Aurelio Uncini.
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Uncini, Aurelio. author., SpringerLink (Online service), Uncini, Aurelio. author., and SpringerLink (Online service)
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This book is an accessible guide to adaptive signal processing methods that equips the reader with advanced theoretical and practical tools for the study and development of circuit structures and provides robust algorithms relevant to a wide variety of application scenarios. Examples include multimodal and multimedia communications, the biological and biomedical fields, economic models, environmental sciences, acoustics, telecommunications, remote sensing, monitoring, and, in general, the modeling and prediction of complex physical phenomena. The reader will learn not only how to design and implement the algorithms but also how to evaluate their performance for specific applications utilizing the tools provided. While using a simple mathematical language, the employed approach is very rigorous. The text will be of value both for research purposes and for courses of study.
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- 2015
107. Algorithms and Discrete Applied Mathematics : First International Conference, CALDAM 2015, Kanpur, India, February 8-10, 2015. Proceedings / edited by Sumit Ganguly, Ramesh Krishnamurti.
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Ganguly, Sumit. editor., Krishnamurti, Ramesh. editor., SpringerLink (Online service), Ganguly, Sumit. editor., Krishnamurti, Ramesh. editor., and SpringerLink (Online service)
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This book collects the refereed proceedings of the First International Conference onon Algorithms and Discrete Applied Mathematics, CALDAM 2015, held in Kanpur, India, in February 2015. The volume contains 26 full revised papers from 58 submissions along with 2 invited talks presented at the conference.The workshop covered a diverse range of topics on algorithms and discrete mathematics, including computational geometry, algorithms including approximation algorithms, graph theory and computational complexity.
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- 2015
108. Discontinuous Galerkin Method : Analysis and Applications to Compressible Flow / by Vít Dolejší, Miloslav Feistauer.
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Dolejší, Vít. author., Feistauer, Miloslav. author., SpringerLink (Online service), Dolejší, Vít. author., Feistauer, Miloslav. author., and SpringerLink (Online service)
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The subject of the book is the mathematical theory of the discontinuous Galerkin method (DGM), which is a relatively new technique for the numerical solution of partial differential equations. The book is concerned with the DGM developed for elliptic and parabolic equations and its applications to the numerical simulation of compressible flow. Itdeals with the theoretical as well as practical aspects of the DGM and treats the basic concepts and ideas of the DGM, as well as the latest significant findings and achievements in this area. The main benefit for readers and the book’s uniqueness lie in the fact that it is sufficiently detailed, extensive and mathematically precise, while at the same time providing a comprehensible guide through a wide spectrum of discontinuous Galerkin techniques and a survey ofthe latest efficient, accurate and robust discontinuous Galerkin schemes for thesolution of compressible flow.
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- 2015
109. Numerical Algebra, Matrix Theory, Differential-Algebraic Equations and Control Theory : Festschrift in Honor of Volker Mehrmann / edited by Peter Benner, Matthias Bollh fer, Daniel Kressner, Christian Mehl, Tatjana Stykel.
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Benner, Peter. editor., Bollh fer, Matthias. editor., Kressner, Daniel. editor., Mehl, Christian. editor., Stykel, Tatjana. editor., SpringerLink (Online service), Benner, Peter. editor., Bollh fer, Matthias. editor., Kressner, Daniel. editor., Mehl, Christian. editor., Stykel, Tatjana. editor., and SpringerLink (Online service)
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This edited volume highlights the scientific contributions of Volker Mehrmann, a leading expert in the area of numerical (linear) algebra, matrix theory, differential-algebraic equations and control theory. These mathematical research areas are strongly related and often occur in the same real-world applications. The main areas where such applications emerge are computational engineering and sciences, but increasingly also social sciences and economics. This book also reflects some of Volker Mehrmann's major career stages. Starting out working in the areas of numerical linear algebra (his first full professorship at TU Chemnitz was in "Numerical Algebra," hence the title of the book) and matrix theory, Volker Mehrmann has made significant contributions to these areas ever since. The highlights of these are discussed in Parts I and II of the present book. Often the development of new algorithms in numerical linear algebra is motivated by problems in system and control theory. These and his later major work on differential-algebraic equations, to which he together with Peter Kunkel made many groundbreaking contributions, are the topic of the chapters in Part III. Besides providing a scientific discussion of Volker Mehrmann's work and its impact on the development of several areas of applied mathematics, the individual chapters stand on their own as reference works for selected topics in the fields of numerical (linear) algebra, matrix theory, differential-algebraic equations and control theory.
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- 2015
110. An Introduction to Modern Analysis / by Vicente Montesinos, Peter Zizler, V clav Zizler.
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Montesinos, Vicente. author., Zizler, Peter. author., Zizler, V clav. author., SpringerLink (Online service), Montesinos, Vicente. author., Zizler, Peter. author., Zizler, V clav. author., and SpringerLink (Online service)
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Examining the basic principles in real analysis and their applications, this text provides a self-contained resource for graduate and advanced undergraduate courses. It contains independent chapters aimed at various fields of application, enhanced by highly advanced graphics and results explained and supplemented with practical and theoretical exercises. The presentation of the book is meant to provide natural connections to classical fields of applications such as Fourier analysis or statistics. However, the book also covers modern areas of research, including new and seminal results in the area of functional analysis.
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- 2015
111. Handbook of Mathematical Methods in Imaging / edited by Otmar Scherzer.
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Scherzer, Otmar. editor., SpringerLink (Online service), Scherzer, Otmar. editor., and SpringerLink (Online service)
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The Handbook of Mathematical Methods in Imaging provides a comprehensive treatment of the mathematical techniques used in imaging science. The material is grouped into two central themes, namely, Inverse Problems (Algorithmic Reconstruction) and Signal and Image Processing. Each section within the themes covers applications (modeling), mathematics, numerical methods (using a case example) and open questions. Written by experts in the area, the presentation is mathematically rigorous. This expanded and revised second edition contains updates to existing chapters and 16 additional entries on important mathematical methods such as graph cuts, morphology, discrete geometry, PDEs, conformal methods, to name a few. The entries are cross-referenced for easy navigation through connected topics. Available in both print and electronic forms, the handbook is enhanced by more than 200 illustrations and an extended bibliography. It will benefit students, scientists and researchers in applied mathematics. Engineers and computer scientists working in imaging will also find this handbook useful.
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- 2015
112. Analytic Number Theory : In Honor of Helmut Maier’s 60th Birthday / edited by Carl Pomerance, Michael Th. Rassias.
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Pomerance, Carl. editor., Rassias, Michael Th. editor., SpringerLink (Online service), Pomerance, Carl. editor., Rassias, Michael Th. editor., and SpringerLink (Online service)
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This volume contains a collection of research and survey papers written by some of the most eminent mathematicians in the international community and is dedicated to Helmut Maier, whose own research has been groundbreaking and deeply influential to the field. Specific emphasis is given to topics regarding exponential and trigonometric sums and their behavior in short intervals, anatomy of integers and cyclotomic polynomials, small gaps in sequences of sifted prime numbers, oscillation theorems for primes in arithmetic progressions, inequalities related to the distribution of primes in short intervals, the Möbius function, Euler’s totient function, the Riemann zeta function and the Riemann Hypothesis. Graduate students, research mathematicians, as well as computer scientists and engineers who are interested in pure and interdisciplinary research, will find this volume a useful resource. Contributors to this volume: Bill Allombert, Levent Alpoge, Nadine Amersi, Yuri Bilu, Régis de la Bretèche, Christian Elsholtz, John B. Friedlander, Kevin Ford, Daniel A. Goldston, Steven M. Gonek, Andrew Granville, Adam J. Harper, Glyn Harman, D. R. Heath-Brown, Aleksandar Ivić, Geoffrey Iyer, Jerzy Kaczorowski, Daniel M. Kane, Sergei Konyagin, Dimitris Koukoulopoulos, Michel L. Lapidus, Oleg Lazarev, Andrew H. Ledoan, Robert J. Lemke Oliver, Florian Luca, James Maynard, Steven J. Miller, Hugh L. Montgomery, Melvyn B. Nathanson, Ashkan Nikeghbali, Alberto Perelli, Amalia Pizarro-Madariaga, János Pintz, Paul Pollack, Carl Pomerance, Michael Th. Rassias, Maksym Radziwiłł, Joël Rivat, András Sárközy, Jeffrey Shallit, Terence Tao, Gérald Tenenbaum, LászlóTóth, Tamar Ziegler, Liyang Zhang.
- Published
- 2015
113. The Future Use of Nordic Forests : A Global Perspective / edited by Erik Westholm, Karin Beland Lindahl, Florian Kraxner.
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Westholm, Erik. editor., Beland Lindahl, Karin. editor., Kraxner, Florian. editor., SpringerLink (Online service), Westholm, Erik. editor., Beland Lindahl, Karin. editor., Kraxner, Florian. editor., and SpringerLink (Online service)
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Diverse as they are in their histories and in the organization of their forest sectors, most Nordic countries have this in common: their economies and cultures are substantially based on the utilization of various forest resources.This book explores Nordic forest futures and presents research results that form part of a scientific foundation for considering how to balance the functions of forests. It is particularly concerned with global trends that may affect the future use of boreal forests. Chapters investigate inter-alia the growing world population and the expected economic growth in countries with huge populations, and assess the resulting pressure on all land-based resources. Authors examine the urgent need for solutions to the energy crisis, consider worrying climate scenarios and provide a global outlook on bioenergy futures. Readers will discover how these developments will and must influence long-term strategic decisions on the future use of Nordic forests. The challenges and possible responses for future forest governance and forestry issues emerge, as the chapters go on to consider the multiple pressures in particular on the Swedish Forestry Model, among other themes. “By bringing together a distinguished group of internationally renowned scientists representing a diverse set of disciplines covering political science, geography, rural development, forest economics, history, and geo-sciences, this book constitutes an exceptionally profound and thoughtful futures study.” – Alexander Buck, Executive Director, International Union of Forest Research Organizations (IUFRO).
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- 2015
114. Digital Fourier Analysis: Advanced Techniques / by Ken'iti Kido.
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Kido, Ken'iti. author., SpringerLink (Online service), Kido, Ken'iti. author., and SpringerLink (Online service)
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This textbook is a thorough, accessible introduction to advanced digital Fourier analysis for advanced undergraduate and graduate students. Assuming knowledge of the Fast Fourier Transform, this book covers advanced topics including the Hilbert transform, cepstrum analysis, and the two-dimensional Fourier transform. Saturated with clear, coherent illustrations, "Digital Fourier Analysis - Advanced Techniques" includes practice problems and thorough Appendices. As a central feature, the book includes interactive applets (available online) that mirror the illustrations. These user-friendly applets animate concepts interactively, allowing the user to experiment with the underlying mathematics. The applet source code in Visual Basic is provided online, enabling advanced students to tweak and change the programs for more sophisticated results. A complete, intuitive guide, "Digital Fourier Analysis - Advanced Techniques" is an essential reference for students in science and engineering.
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- 2015
115. Meshfree Methods for Partial Differential Equations VII / edited by Michael Griebel, Marc Alexander Schweitzer.
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Griebel, Michael. editor., Schweitzer, Marc Alexander. editor., SpringerLink (Online service), Griebel, Michael. editor., Schweitzer, Marc Alexander. editor., and SpringerLink (Online service)
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Meshfree methods, particle methods, and generalized finite element methods have witnessed substantial development since the mid 1990s. The growing interest in these methods is due in part to the fact that they are extremely flexible numerical tools and can be interpreted in a number of ways. For instance, meshfree methods can be viewed as a natural extension of classical finite element and finite difference methods to scattered node configurations with no fixed connectivity. Furthermore, meshfree methods offer a number of advantageous features which are especially attractive when dealing with multiscale phenomena: a priori knowledge about particular local behavior of the solution can easily be introduced in the meshfree approximation space, and coarse-scale approximations can be seamlessly refined with fine-scale information. This volume collects selected papers presented at the Seventh International Workshop on Meshfree Methods, held in Bonn, Germany in September 2013. They address various aspects of this highly dynamic research field and cover topics from applied mathematics, physics and engineering.
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- 2015
116. Computer Algebra and Polynomials : Applications of Algebra and Number Theory / edited by Jaime Gutierrez, Josef Schicho, Martin Weimann.
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Gutierrez, Jaime. editor., Schicho, Josef. editor., Weimann, Martin. editor., SpringerLink (Online service), Gutierrez, Jaime. editor., Schicho, Josef. editor., Weimann, Martin. editor., and SpringerLink (Online service)
- Abstract
Algebra and number theory have always been counted among the most beautiful mathematical areas with deep proofs and elegant results. However, for a long time they were not considered that important in view of the lack of real-life applications. This has dramatically changed: nowadays we find applications of algebra and number theory frequently in our daily life. This book focuses on the theory and algorithms for polynomials over various coefficient domains such as a finite field or ring. The operations on polynomials in the focus are factorization, composition and decomposition, basis computation for modules, etc. Algorithms for such operations on polynomials have always been a central interest in computer algebra, as it combines formal (the variables) and algebraic or numeric (the coefficients) aspects. The papers presented were selected from the Workshop on Computer Algebra and Polynomials, which was held in Linz at the Johann Radon Institute for Computational and Applied Mathematics (RICAM) during November 25-29, 2013, at the occasion of the Special Semester on Applications of Algebra and Number Theory.
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- 2015
117. Inverse Problems and Applications / edited by Larisa Beilina.
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Beilina, Larisa. editor., SpringerLink (Online service), Beilina, Larisa. editor., and SpringerLink (Online service)
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This proceeding volume is based on papers presented on the Third Annual Workshop on Inverse Problems which was organized by the Department of Mathematical Sciences, Chalmers University of Technology and University of Gothenburg, and took place in May 2013 in Stockholm. The purpose of this workshop was to present new analytical developments and numerical techniques for solution of inverse problems for a wide range of applications in acoustics, electromagnetics, optical fibers, medical imaging, geophysics, etc. The contributions in this volume reflect these themes and will be beneficial to researchers who are working in the area of applied inverse problems.
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- 2015
118. New Challenges in Grid Generation and Adaptivity for Scientific Computing / edited by Simona Perotto, Luca Formaggia.
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Perotto, Simona. editor., Formaggia, Luca. editor., SpringerLink (Online service), Perotto, Simona. editor., Formaggia, Luca. editor., and SpringerLink (Online service)
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This volume collects selected contributions from the “Fourth Tetrahedron Workshop on Grid Generation for Numerical Computations”, which was held in Verbania, Italy in July 2013. The previous editions of this Workshop were hosted by the Weierstrass Institute in Berlin (2005), by INRIA Rocquencourt in Paris (2007), and by Swansea University (2010). This book covers different, though related, aspects of the field: the generation of quality grids for complex three-dimensional geometries; parallel mesh generation algorithms; mesh adaptation, including both theoretical and implementation aspects; grid generation and adaptation on surfaces – all with an interesting mix of numerical analysis, computer science and strongly application-oriented problems.
- Published
- 2015
119. Mathematical modeling of Emiliania huxleyi and a host-specific virus
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Middleton, Julia and Middleton, Julia
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- Coccolithus huxleyi., Marine biology., Numerical analysis., Oceanography., Biologie marine., Analyse numérique., Océanographie., marine biology., oceanography., Coccolithus huxleyi, Marine biology, Numerical analysis, Oceanography
- Abstract
The world's oceans provide the basis for life on the planet. One microscopic algae, the coccolithophores, and Emiliania huxleyi in particular, is a major source of carbon drawdown in the context of the global carbon cycle and account for a significant amount of the primary production in oceanic ecosystems. We know that the oceans are packed with marine viruses and they have an important role in the rise and fall of plankton populations but current mathematical models do not accurately account for virus-host interactions when predicting plankton blooms. Therefore I am using model optimization and comparison techniques to evaluate current models and reassess how the virus-host system should be described. Analysis of in situ blooms and mesocosm data has revealed previously unreported trends occurring over the course of an E. huxleyi bloom. Inclusion of virus-host interactions in models describing the calcifying coccolithophore E. huxleyi may give insight into global carbon cycling, as large-scale blooms are known to draw down significant amounts of atmospheric carbon.
- Published
- 2015
120. Modelling the fracture of concrete under mixed loading
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Cendón, D.A., Gálvez, J.C., Elices, M., and Planas, J.
- Published
- 2000
- Full Text
- View/download PDF
121. Mixed Mode Fracture of Concrete under Proportional and Nonproportional Loading
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Gálvez, J.C., Elices, M., Guinea, G.V., and Planas, J.
- Published
- 1998
- Full Text
- View/download PDF
122. Temperature and Thermoelastic Instability at Tread Braking Using Cast Iron Friction Material
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Abbasi, Saeed, Teimourimanesh, Shahab, Vernersson, Tore, Sellgren, Ulf, Olofsson, Ulf, Lunden, Roger, Abbasi, Saeed, Teimourimanesh, Shahab, Vernersson, Tore, Sellgren, Ulf, Olofsson, Ulf, and Lunden, Roger
- Abstract
Braking events in railway traffic often induce high frictional heating and thermoelastic instability (TEI) at the interfacing surfaces. In the present paper, two approaches are adopted to analyse the thermomechanical interaction in a pin-on-disc experimental study of railway braking materials. In a first part, the thermal problem is studied to find the heat partitioning between pin and disc motivated by the fact that wear mechanisms can be explained with a better understanding of the prevailing thermal conditions. The numerical model is calibrated using the experimental results. In a second part, the frictionally induced thermoelastic instabilities at the pin-disc contact are studied using a numerical method and comparing them with the phenomena observed in the experiments. The effects of temperature on material properties and on material wear are considered. It is found from the thermal analysis that the pin temperature and the heat flux to the pin increase with increasing disc temperatures up to a transition stage. This agrees with the behaviour found in the experiments. Furthermore, the thermoelastic analysis displays calculated pressure and the temperature distributions at the contact interface that are in agreement with the hot spot behaviour observed in the experiments., QC 20140422Updated from accepted to published.
- Published
- 2013
- Full Text
- View/download PDF
123. Models for analysis of shotcrete on rock exposed to blasting
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Ahmed, Lamis and Ahmed, Lamis
- Abstract
In underground construction and tunnelling, the strive for a more time-efficient construction process naturally focuses on the possibilities of reducing the times of waiting between stages of construction. The ability to project shotcrete (sprayed concrete) on a rock surface at an early stage after blasting is vital to the safety during construction and function of e.g. a tunnel. A complication arises when the need for further blasting affects the hardening of newly applied shotcrete. If concrete, cast or sprayed, is exposed to vibrations at an early age while still in the process of hardening, damage that threatens the function of the hard concrete may occur. There is little, or no, established knowledge on the subject and there are no guidelines for practical use. It is concluded from previous investigations that shotcrete can withstand high particle velocity vibrations without being seriously damaged. Shotcrete without reinforcement can survive vibration levels as high as 0.5−1 m/s while sections with loss of bond and ejected rock will occur for vibration velocities higher than 1 m/s. The performance of young and hardened shotcrete exposed to high magnitudes of vibration is here investigated to identify safe distances and shotcrete ages for underground and tunnelling construction, using numerical analyses and comparison with measurements and observations. The work focuses on finding correlations between numerical results, measurement results and observations obtained during tunnelling. The outcome will be guidelines for practical use. The project involves development of sophisticated dynamic finite element models for which the collected information and data will be used as input, accomplished by using the finite element program Abaqus. The models were evaluated and refined through comparisons between calculated and measured data. First, existing simple engineering models were compared and evaluated through calculations and comparisons with existing data. The fir, Inom undermarks- och tunnelbyggande leder strävan efter en mer tidseffektiv byggprocess till fokus på möjligheten att reducera väntetiderna mellan byggetapper. Möjligheten att projicera sprutbetong på bergytor i ett tidigt skede efter sprängning är avgörande för säkerheten under konstruktionen av t.ex. en tunnel. En komplikation uppstår när behovet av ytterligare sprängning kan påverka härdningen av nysprutad betong. Om betong, gjuten eller sprutad, utsätts för vibrationer i ett tidigt skede under härdningsprocessen kan skador som hotar funktionen hos den hårdnade betongen uppstå. Kunskapen i ämnet är knapphändig, eller obefintlig, och det finns inga etablerade riktlinjer för praktisk användning. Slutsatsen från tidigare undersökningar visar att sprutbetong kan tåla höga vibrationer (partikelhastigheter) utan att allvarliga skador uppstår. Oarmerad sprutbetong kan vara oskadd efter att ha utsatts för så höga vibrationsnivåer som 0,5–1 m/s medan partier med förlorad vidhäftning till berget kan uppträda vid vibrationshastigheter högre än 1 m/s. Funktionen hos ung och hårdnande sprutbetong som utsätts för höga vibrationsnivåer undersöks här för att identifiera säkra avstånd och sprutbetongåldrar för undermarks- och tunnelbyggande, med hjälp av numeriska analyser och jämförelser med mätningar och observationer. Arbetet fokuserar på att finna samband mellan numeriska resultat, mätresultat och observationer från tunnelbyggande. Det slutliga resultatet kommer att vara riktlinjer för praktisk användning. Projektet omfattar utveckling av sofistikerade dynamiska finita elementmodeller för vilka insamlad information och data kommer att användas som indata för det finita elementprogrammet Abaqus. Modellerna utvärderades och förfinats genom jämförelser mellan beräknade och uppmätta resultat. Först jämfördes befintliga enkla mekaniska, ingenjörsmässiga modeller vilka utvärderades genom beräkningar och jämförelser med befintliga data. Den första modellen är en strukturdynamisk mod, QC 20120427
- Published
- 2012
124. Numerical analysis of a tape spring hinge folded about two axes
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Maji, Arup K, Ng, Percy, Ghosh, Ashok K, Estvanko, Bryan, Maji, Arup K, Ng, Percy, Ghosh, Ashok K, and Estvanko, Bryan
- Subjects
- Expandable space structures--Computer simulation
- Abstract
The ability to fold and unfold large sensor structures in space using hinges is important for space-based sensor technology. Tape spring hinges have become common in deployable space structures due to simplicity, repeatability and unique folding properties. The mechanical response of these hinges (moment-curvature, energy stored etc.) is important in ensuring safety, deployment accuracy as well as optimizing cost of the structure. In an effort to learn more about the folding and deployment properties, finite element software, Abaqus\u2122, was used to analyze a hinge using multidirectional bending. The analysis involved large deformation (rotation through 180 degrees), nonlinear geometric loading. In order to increase confidence in the analysis procedures, a study was conducted on how the type and size of elements affects stability and buckling of a simply-supported plate. In order to fold a tape spring, a specified length of the middle segment of the hinge was first flattened, so the initial curvature about the long axis of the hinge was removed. This minimizes the moment of inertia and hence stiffness allowing it to be folded. With the middle segment flattened, the hinge was subjected to opposite-sense bending about the hinges short axis (axis perpendicular to the length of the tape spring). In addition to providing the needed mechanical response, the study allowed investigation into the optimum method of folding a hinge. Energy stored during folding and unfolding could be evaluated which allows the designer to determine adequate passive damping to obtain necessary post-deployment stability and pointing accuracy.'
- Published
- 2012
125. Numerical analysis of Aberdeen Pool sedimentation
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Clifton, Nathan Dwayne and Clifton, Nathan Dwayne
- Subjects
- Sediment transport., Fluid dynamics Models., Numerical analysis., Sédiments (Géologie) Transport., Analyse numérique., Fluid dynamics Models, Numerical analysis, Sediment transport, Tennessee-Tombigbee Waterway (Ala. and Miss.), United States Tennessee-Tombigbee Waterway
- Abstract
The main objective of this research was to create a two dimensional and three dimensional Environmental Fluid Dynamics Code (EFDC) model using Aberdeen Pool of the Tennessee-Tombigbee Waterway for the purpose of determining the differences in their ability to address sediment transport. These objectives were reached in the results with comparisons of water levels, sediment concentrations, shear stress, and bed change. The models produced very similar results for the majority of the sediment transport throughout both models with the overall trend being deposition except in the upper limits of the Tombigbee River. The main differences between the two models are produced from the 2D model being depth averaged and the 3D being able to transport sediment vertically. The results show the 2D model tends to erode less and deposit more whereas the 3D model tends to follow the same pattern except for less deposition with more erosion.
- Published
- 2011
126. Waterhammer modeling for the Ares I Upper Stage Reaction Control System cold flow development test article
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Williams, J. Hunter and Williams, J. Hunter
- Subjects
- Water hammer Computer simulation., Hydraulic transients Computer simulation., Water-pipes Hydrodynamics Computer simulation., Numerical analysis., Launch vehicles (Astronautics) Control systems., Coup de bélier Simulation par ordinateur., Régime transitoire (Hydraulique) Simulation par ordinateur., Tuyaux d'eau Hydrodynamique Simulation par ordinateur., Analyse numérique., Launch vehicles (Astronautics) Control systems., Numerical analysis.
- Abstract
The Upper Stage Reaction Control System provides in-flight three-axis attitude control for the Ares I Upper Stage. The system design must accommodate rapid thruster firing to maintain proper launch trajectory and thus allow for the possibility to pulse multiple thrusters simultaneously. Rapid thruster valve closure creates an increase in static pressure, known as waterhammer, which propagates throughout the propellant system at pressures exceeding nominal design values. A series of development tests conducted at Marshall Space Flight Center in 2009 were performed using a water-flow test article to better understand fluid characteristics of the Upper Stage Reaction Control System. A subset of the tests examined the waterhammer pressure and frequency response in the flight-representative system and provided data to anchor numerical models. This thesis presents a comparison of waterhammer test results with numerical model and analytical results. An overview of the flight system, test article, modeling and analysis are also provided.
- Published
- 2010
127. Numerical linear approximation in C
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Malek, William Alexander, 1960, Abdelmalek, Nabih N., Malek, William Alexander, 1960, and Abdelmalek, Nabih N.
- Published
- 2008
128. Numerical modeling of explosives and propellants
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Mader, Charles L. and Mader, Charles L.
- Published
- 2008
129. A simplified physical model to determine the lightning upward connecting leader inception
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Becerra, Marley, Cooray, Vernon, Becerra, Marley, and Cooray, Vernon
- Abstract
In this paper, a generalized leader inception model isproposed. It is based on an iterative geometrical analysis of thebackground potential distribution of an earthed structure to simulatethe first meters of propagation of an upward connecting leader.By assuming a static field approach, the leader stabilization fieldsand the striking distances were computed for a lightning rod andfor a building. The obtained results were compared with the existingleader inception criteria. Furthermore, in order to validatethe model, the leader inception condition was computed for a triggeredlightning experiment. Excellent agreement with the experimentalresults was obtained. The present model has several advantagesin comparison with the existing leader inception criteria.One of them is related to the fact that the proposed model can beused to analyze the effect of the space charge on the upward leaderinception., QC 20120202
- Published
- 2006
- Full Text
- View/download PDF
130. Particle Simulation of Plume-Plume and Plume-Surface Interactions
- Author
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CALIFORNIA UNIV LOS ANGELES DEPT OF MECHANICAL AND AEROSPACE ENGINEERING, Gimeishein, S. F., Ketsdever, A. D., Wadsworth, D. C., CALIFORNIA UNIV LOS ANGELES DEPT OF MECHANICAL AND AEROSPACE ENGINEERING, Gimeishein, S. F., Ketsdever, A. D., and Wadsworth, D. C.
- Abstract
Numerical modeling of two- and three-dimensional low Reynolds number gas flows from small nozzles has been performed using the direct simulation (DSMC) method. The objective of this effort is to gain an improved understanding of performance and plume interaction phenomena for low thrust devices and thus improve the design and optimization process for a variety of micro-propulsion systems. Simulations were performed for a wide range of flow parameters using the SMILE parallel DSMC code. Validation has been conducted through comparison of mass flow and thrust values obtained numerically with results of experimental measurements carried out recently by AFRL researchers.
- Published
- 2004
131. Reliable methods for computer simulation : error control and a posteriori estimates
- Author
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Repin, Sergey I., Neittaanmaki, P. (Pekka), Repin, Sergey I., and Neittaanmaki, P. (Pekka)
- Published
- 2004
132. Interpolation and approximation by polynomials
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Phillips, G. M. (George McArtney) and Phillips, G. M. (George McArtney)
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- 2003
133. Numerical analysis of wavelet methods
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Cohen, Albert, 1965 and Cohen, Albert, 1965
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- 2003
134. An ODE solver for constrained state spaces: with applications to hybrid-system simulations
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Donolo, Marcos Angel and Donolo, Marcos Angel
- Abstract
This thesis presents a solver to handle constrained-state-space ODEs. This solver locates the points where any of the states go outside of the constraining set, and then, transfers the control from the continuous time ODE to the function governing the behavior of the system on the boundaries of the constrained set. The main contribution of this solver is found simulating complex right-hand-sided ODEs for long periods of time.
- Published
- 2002
135. Nonlinear Analysis in the Science of Materials
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CARNEGIE-MELLON UNIV PITTSBURGH PA DEPT OF MATHEMATICAL SCIENCES, Kinderlehrer, David, CARNEGIE-MELLON UNIV PITTSBURGH PA DEPT OF MATHEMATICAL SCIENCES, and Kinderlehrer, David
- Abstract
This grant supported in part the work of five graduate students at Carnegie Mellon University. The students studied questions in nonlinear analysis, stochastic analysis, and numerical analysis.
- Published
- 2001
136. Operator theory and numerical methods
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Saito, Norikazu., Suzuki, Takashi., Fujita, Hiroshi, 1922, Saito, Norikazu., Suzuki, Takashi., and Fujita, Hiroshi, 1922
- Published
- 2001
137. Electromagnetic Wave Scattering by the Edge of a Carbon Nanotube
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BELARUS STATE UNIV MINSK INST OF NUCLEAR PROBLEMS, Krapivin, N. A., Slepyan, G. Y., Maksimenko, S. A., Lakhtakia, A., Yevtushenko, O. M., BELARUS STATE UNIV MINSK INST OF NUCLEAR PROBLEMS, Krapivin, N. A., Slepyan, G. Y., Maksimenko, S. A., Lakhtakia, A., and Yevtushenko, O. M.
- Abstract
Scattering of a time-harmonic electromagnetic field by the edge of a semi-infinite, singlewall, zigzag carbon nanotube (CN) is considered. The Wiener-Hopf technique is applied to determine the exact solution of the problem, and the scattering pattern is numerically calculated in the vicinity of the main plasmon resonance frequency., Presented at Intl. Conference on Electromagnetics of Complex Media (8th), Lisbon, PT, 27-29 Sep 2000, p253-256. This article is from ADA398724 International Conference on Electromagnetics of Complex Media (8th), Held in Lisbon, Portugal on 27-29 September 2000. Bianisotropics 2000
- Published
- 2000
138. Numerical mathematics
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Sacco, Riccardo., Saleri, Fausto., Quarteroni, Alfio., Sacco, Riccardo., Saleri, Fausto., and Quarteroni, Alfio.
- Published
- 2000
139. Use of innovative shear connectors in construction and rehabilitation of steel-concrete composite beams
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Wijesiri Pathirana, Indika
- Subjects
- Numerical analysis., Composite beams., Push test., Retrofitting., Demountable structures., Bridges., Buildings.
- Abstract
Composite beams are now widely used in infrastructure such as steel-framed bridges, buildings and stadiums. Most of these composite beams have been built with welded shear studs due to the availability of detailed research on their properties, and standard design methods for using them. However, as composite beams age, their ability to withstand current and future loading requirements deteriorates. On the other hand, existing composite beams incorporating welded shear studs cannot be easily retrofitted to prolong their useful service life, nor can the steel and concrete components of these beams be separated securely to be reused due to the permanent fixing mechanism of the welded studs. This thesis attempts to investigate the design and behaviour of composite beams with innovative bolted connectors. The novel fixing mechanisms of these bolted connectors may enable composite beams to be retrofitted reliably and also be disassembled without much effort. With these aims in mind, the emphasis in this thesis is primarily on the following issues: investigating the ability of bolted and welded-stud connectors to achieve composite action in normal and retrofitted composite beams investigating the effects of time-dependent creep and shrinkage of concrete on the behaviour of composite beams incorporating either bolted connectors or welded-stud connectors investigating the feasibility of dismantling composite beams subjected to serviceability loading by removing connector bolts. This thesis comprises many experimental and numerical studies, including the flexural behaviour of composite beams with bolted and welded-stud connectors as well as the load–slip behaviour of the connectors. In addition, the behaviour of the beam and push-out test specimens in their respective experiments was simulated using finite element models developed in ABAQUS software. An extensive parametric study was also carried out using these models in order to gain further insight in to the behaviour of composite beams with bolted and welded-stud connectors in composite steel–concrete beams. The outcome of the experimental and numerical analyses is satisfying and also contains design recommendations. It is strongly hoped that the findings of this study may provide an important basis and guidelines for designing and constructing more robust and sustainable composite beam systems in the future.
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- 2016
140. Plasticity : mathematical theory and numerical analysis
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Reddy, B. Dayanand, 1953, Han, Weimin., Reddy, B. Dayanand, 1953, and Han, Weimin.
- Published
- 1999
141. Theory and applications of numerical analysis
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Taylor, Peter John., Phillips, G. M. (George McArtney), Taylor, Peter John., and Phillips, G. M. (George McArtney)
- Published
- 1996
142. Investigation of stream-aquifer interactions using a coupled surface water and groundwater flow model.
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Neuman, Shlomo, Goodrich, David, Vionnet, Leticia Beatriz, Neuman, Shlomo, Goodrich, David, and Vionnet, Leticia Beatriz
- Abstract
A finite element numerical model is developed for the modeling of coupled surface-water flow and ground-water flow. The mathematical treatment of subsurface flows follows the confined aquifer theory or the classical Dupuit approximation for unconfined aquifers whereas surface-water flows are treated with the kinematic wave approximation for open channel flow. A detailed discussion of the standard approaches to represent the coupling term is provided. In this work, a mathematical expression similar to Ohm's law is used to simulate the interacting term between the two major hydrological components. Contrary to the standard approach, the coupling term is incorporated through a boundary flux integral that arises naturally in the weak form of the governing equations rather than through a source term. It is found that in some cases, a branch cut needs to be introduced along the internal boundary representing the stream in order to define a simply connected domain, which is an essential requirement in the derivation of the weak form of the ground-water flow equation. The fast time scale characteristic of surface-water flows and the slow time scale characteristic of ground-water flows are clearly established, leading to the definition of three dimensionless parameters, namely, a Peclet number that inherits the disparity between both time scales, a flow number that relates the pumping rate and the streamflow, and a Biot number that relates the conductance at the river-aquifer interface to the aquifer conductance. The model, implemented in the Bill Williams River Basin, reproduces the observed streamflow patterns and the ground-water flow patterns. Fairly good results are obtained using multiple time steps in the simulation process.
- Published
- 1995
143. Acoustooptical Coupling of Guided to Substrate Modes in Planar Proton-Exchanged LiNbO3-Waveguides
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PADERBORN UNIV (GERMANY F R), Rust, U., Strake, E., PADERBORN UNIV (GERMANY F R), Rust, U., and Strake, E.
- Abstract
The acoustically induced conversion of guided to substrate modes in optical waveguides has several attractive applications in integrated optics. One of them is an extremely simple RF-spectrum analyzer.The generated radiation field leaves the waveguiding region and propagates into the substrate under a well defined angle, which is determined by the phase matching condition. This deflection angle can be controlled by the acoustical frequency. As guided and radiation modes may be chosen to have orthogonal polarizations, the converted light can easily be detected using a polarizer and an array of photodiodes. We present a method that allows a rigorous numerical simulation of the device under the assumption that both, optical and acoustical waveguides are planar., This Article is from 'Integrated Photonics Research'. Volume 10, AD-A255 423, p94-95.
- Published
- 1992
144. User's Guide: Computer-Aided Structural Modeling (CASM). Version 3.00.
- Author
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WICKERSHEIMER ENGINEERS INC CHAMPAIGN IL, Wickersheimer, David, McDermott, Gene, Roth, Carl, Pace, Michael E., WICKERSHEIMER ENGINEERS INC CHAMPAIGN IL, Wickersheimer, David, McDermott, Gene, Roth, Carl, and Pace, Michael E.
- Abstract
CASM stands for Computer Aided Structural Modeling. It is a program designed to aid the structural engineer in the preliminary design and evaluation of structural building systems by the use of 3-D interactive graphics. Think of this program as a scratch pad for the structural decision process that would have been done on paper before you went to the computer to do the final numerical analysis of structural members. CASM will let you change your mind quickly and give you results that previously might have taken hours to obtain. By allowing quick changes, CASM allows you to make more informed decisions in the initial structural evaluation process. The purpose of this manual is to help you understand the CASM program. The CASM program is designed by structural engineers for structural engineers. Its purpose is to help solve those basic early problems that all engineers face when trying to fit a structural system into a building.
- Published
- 1992
145. Development of a screening method for prioritizing the remediation of groundwater contamination sites : Final report
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Ahlfeld, David P. and Ahlfeld, David P.
- Subjects
- Groundwater Pollution., Numerical analysis., Mathematical optimization., Eau souterraine Pollution., Analyse numérique., Optimisation mathématique., Groundwater Pollution., Mathematical optimization., Numerical analysis.
- Published
- 1992
146. Three Dimensional Unstructured Multigrid for the Euler Equations
- Author
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INSTITUTE FOR COMPUTER APPLICATIONS IN SCIENCE AND ENGINEERING HAMPTON VA, Mavriplis, D. J., INSTITUTE FOR COMPUTER APPLICATIONS IN SCIENCE AND ENGINEERING HAMPTON VA, and Mavriplis, D. J.
- Abstract
The three dimensional Euler equations are solved on unstructured tetrahedral meshes using a multigrid strategy. The driving algorithm consists of an explicit vertex-based finite element scheme, which employs an edge-based data-structure to assemble the residuals. The multigrid approach employs a sequence of independently generated coarse and fine meshes to accelerate the convergence to steady state of the fine grid solution. Variables and corrections are passed back and forth between the various grids of the sequence using linear interpolation. The addresses and weights for interpolation are determined in a preprocessing stage using an efficient graph traversal algorithm. The preprocessing operation is shown to require a negligible fraction of the CPU time required by the overall solution procedure, while grains in overall solution efficiencies greater than an order of magnitude are demonstrated on meshes containing up to 350,000 vertices. Solutions using globally regenerated fine meshes as well as adaptively refined meshes are given.
- Published
- 1991
147. Investigation of the Effects of Increased Order Compensators in Mixed H2/H(Infinity) Optimization
- Author
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AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING, Wells, Scott R., AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING, and Wells, Scott R.
- Abstract
The problem of minimizing the 2-norm of one transfer function subject to an infinity-norm bound on another transfer function is examined for increased order controllers. In particular, the theoretical results of the full order case are extended to the higher order case, and SISO and MIMO numerical examples are given for increasingly higher order compensators. Some of the key proofs for higher order compensators include: the global minimum 2-norm is unachievable under output feedback for certain levels of gamma regardless of compensator order; the solution to the mixed H2/H infinity problem lies on the boundary of the infinity-norm constraint for this same range of gamma's; and the suboptimal mixed problem converges to the optimal in the limit for higher order controllers. Also, it is shown that the optimal compensator order for the mixed H2/H infinity problem is greater than the order of the plant under certain conditions, and a conjecture about the optimal order for the mixed problem is made.
- Published
- 1991
148. A Theory of Inverse Operators for Multiple Excitations
- Author
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DAYTON UNIV OH SCHOOL OF ENGINEERING, Pasala, Krishna M., DAYTON UNIV OH SCHOOL OF ENGINEERING, and Pasala, Krishna M.
- Abstract
In this report we consider the solution to integral equations that arise in the theory of electromagnetic scattering. We develop an interactive solution valid not for just one excitation but multiple excitations. We first consider a matrix equation obtained as a projection of the integral equation to finite dimensional space. After each iteration an orthogonal vector is determined and from it a corresponding component of the inverse operator. Thus, after each iteration a best estimate to the inverse operator is determined. This may be used to obtain the estimated solution to an arbitrary number of excitations. It is shown that the outer product of the vectors needs to be computed to compute the inverse operator. Since this is an expensive operation, an alternative approach is determined whereby solution to multiple excitations is determined without computing the outer products. This theory, developed in N- dimensional space, is then generalized to infinite dimensional space. This leads to a definition and a computational procedure for inverse integral operator. The theory is illustrated by computing the induced currents on a square cylinder for several excitations.
- Published
- 1991
149. Higher-Order Thickness Expansions for Cylindrical Shells
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AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING, Smith, Randy A., AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING, and Smith, Randy A.
- Abstract
Eight variations of higher-order transverse shear deformation (HTSD) theory were developed for composite shells. Three attributes were varied to produce the eight variations. These attributes include the order of the thickness expansions used to approximate the shell shape factors and the assumed linear displacement field and the nonlinearity of transverse shear strain. Several cylindrical shell problems were investigated using SHELL, a finite- element code with a 36 degree of freedom cylindrical shell element. MACSYMA, a symbolic manipulation code, was used to formulate the element independent stiffness arrays for each variation of the theory. When all nonlinear strain- displacement terms for transverse shear were included for thin shallow isotropic cylindrical shells, the theory predicted a more flexible response during collapse. Higher-order thickness expansions had negligible effect upon results for shallow shell problems investigated. For deeper shells, the linear displacement assumption prohibited the use of nonlinear strain-displacement relations for transverse shear strains. Thus, for deep shells nonlinearity was limited to in-plane strain-displacement relations.
- Published
- 1991
150. Asynchronous and Corrected-Asynchronous Numerical Solutions of Parabolic PDEs on MIMD Multiprocessors.
- Author
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INSTITUTE FOR COMPUTER APPLICATIONS IN SCIENCE AND ENGINEERING HAMPTON VA, Amitai, Dganit, Averbuch, Amir, Itzikowitz, Samuel, Turkel, Eli, INSTITUTE FOR COMPUTER APPLICATIONS IN SCIENCE AND ENGINEERING HAMPTON VA, Amitai, Dganit, Averbuch, Amir, Itzikowitz, Samuel, and Turkel, Eli
- Abstract
A major problem in achieving significant speed-up on parallel machines is the overhead involved with synchronizing the concurrent processes. Removing the synchronization constraint has the potential of speeding up the computation. We present asynchronous (AS) and corrected-asynchronous (CA) finite difference schemes for the multi-dimensional heat equation. Although our discussion concentrates on the Euler scheme for the solution of the heat equation, it has the potential of being extended to other schemes and other parabolic partial differential equations. These schemes are analyzed and implemented on the shared memory multi-user Sequent Balance machine . Numerical results for one and two dimensional problems are presented. It is shown experimentally that synchronization penalty can be about 50% of run time: in most cases, the asynchronous scheme runs twice as fast as the parallel synchronous scheme. In general, the efficiency of the parallel schemes increases with processor load, with the time-level, and with the problem dimension. The efficiency of the AS may reach 90% and over, but it provides accurate results only for steady-state values. The CA, on the other hand, is less efficient but provides more accurate results for intermediate (non steady-state) values.
- Published
- 1991
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