Download or read book Optimization of Acoustic Source Strength in the Problems of Active Noise Control written by Josip Lončarić and published by . This book was released on 2002 with total page 46 pages. Available in PDF, EPUB and Kindle. Book excerpt: We consider a problem of eliminating the unwanted time-harmonic noise on a predetermined region of interest. The desired objective is achieved by active means, i.e., by introducing additional sources of sound called control sources, that generate the appropriate annihilating acoustic signal (anti-sound). A general solution for the control sources has been obtained previously in both continuous and discrete formulation of the problem. In the current paper, we focus on optimizing the overall absolute acoustic source strength of the control sources. Mathematically, this amounts to the minimization of multi-variable complex-valued functions in the sense of L1 with conical constraints, which are only 'marginally' convex. The corresponding numerical optimization problem appears very challenging even for the most sophisticated state-of-the-art methodologies, and even when the dimension of the grid is small, and the waves are long. Our central result is that the global L1-optimal solution can, in fact, be obtained without solving the numerical optimization problem. This solution is given by a special layer of monopole sources on the perimeter of the protected region. We provide a rigorous proof of the global L1 minimality for both continuous and discrete optimization problems in the one-dimensional case. We also provide numerical evidence that corroborates our result in the two-dimensional case, when the protected domain is a cylinder. Even though we cannot fully justify it, we believe that the same result holds in the general case, i.e., for multi-dimensional settings and domains of arbitrary shape. We formulate it as a conjecture at the end of the paper.
Download or read book Quadratic Optimization in the Problems of Active Control of Sound written by Josip Lončarić and published by DIANE Publishing. This book was released on 2002 with total page 30 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Quadratic Optimization in the Problems of Active Control of Sound written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-06-04 with total page 30 pages. Available in PDF, EPUB and Kindle. Book excerpt: We analyze the problem of suppressing the unwanted component of a time-harmonic acoustic field (noise) on a predetermined region of interest. The suppression is rendered by active means, i.e., by introducing the additional acoustic sources called controls that generate the appropriate anti-sound. Previously, we have obtained general solutions for active controls in both continuous and discrete formulations of the problem. We have also obtained optimal solutions that minimize the overall absolute acoustic source strength of active control sources. These optimal solutions happen to be particular layers of monopoles on the perimeter of the protected region. Mathematically, minimization of acoustic source strength is equivalent to minimization in the sense of L(sub 1). By contrast. in the current paper we formulate and study optimization problems that involve quadratic functions of merit. Specifically, we minimize the L(sub 2) norm of the control sources, and we consider both the unconstrained and constrained minimization. The unconstrained L(sub 2) minimization is certainly the easiest problem to address numerically. On the other hand, the constrained approach allows one to analyze sophisticated geometries. In a special case, we call compare our finite-difference optimal solutions to the continuous optimal solutions obtained previously using a semi-analytic technique. We also show that the optima obtained in the sense of L(sub 2) differ drastically from those obtained in the sense of L(sub 1).Loncaric, J. and Tsynkov, S. V. and Bushnell, Dennis M. (Technical Monitor)Langley Research CenterNOISE SPECTRA; ACOUSTIC FREQUENCIES; NOISE REDUCTION; OPTIMIZATION; ACTIVE CONTROL; MATHEMATICAL MODELS; NUMERICAL ANALYSIS; MONOPOLES; SOUND FIELDS; SOUND GENERATORS
Download or read book Designing Quiet Structures written by Gary H. Koopmann and published by Elsevier. This book was released on 1997-10-13 with total page 261 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is the first of its kind. It provides the reader with a logical and highly quantitative means of including noise as a parameter in the early design stages of a machine or structure. The unique and unified methodology builds upon the familiar disciplines of acoustics, structural dynamics and optimization. It also exemplifies the art of simplification - the essence of all good engineering design. Strategies for designing quiet structures require extensive analytical and experimental tools. For computing the sound power from complex structures the authors recommend a new 3-D, lumped parameter formulation. This fully developed, user-friendly program can be applied generally to noise-control-by-design problems. Detailed instructions for running the application are given in the appendix as well as several sample problems to help the user get started. The authors also describe a new instrument: a specially developed resistance probe used to measure a structure=92s acoustic surface resistance. As an example, the procedure is outlined for measuring the valve cover of an internal combustion engine. Indeed, throughout the book the reader is presented with actual experiments, numerical and physical that they can replicate in their own laboratory. This is a must-have book for engineers working in industries that include noise control in the design of a product. Its practical and didactic approach also makes it ideally suited to graduate students. First text covering the design of quiet structures Written by two of the leading experts in the world in the area of noise control Strong in its integration of structural dynamics, acoustics, and optimization theory Accompanied by a computer program that allows the computation of sound power Presents numerous applications of noise-control-by-design methods as well as methods for enclosed and open spaces Each chapter is supported by homework problems and demonstration experiments
Download or read book Solutions to Example Problems in Engineering Noise Control written by Colin H. Hansen and published by Causal Systems. This book was released on 2003 with total page 338 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is the solution manual for Problems in Engineering Noise Control by the same author. The solutions are very detailed and comprehensive and extend a number of concepts with approximately 270 problems which have a total of 650 separate parts.
Download or read book Active Noise Control Primer written by Scott D. Snyder and published by Springer Science & Business Media. This book was released on 2012-09-25 with total page 172 pages. Available in PDF, EPUB and Kindle. Book excerpt: By providing all the basic knowledge needed to assess how useful active noise control will be for a given problem, this book assists in the designing, setting up, and tuning of an active noise-control system. Written for students who have no prior knowledge of acoustics, signal processing, or noise control but who do have a reasonable grasp of basic physics and mathematics, the text is short and descriptive, leaving all mathematical details and proofs concerning vibrations, signal processing and the like to more advanced texts or research monographs. The book can thus be used in independent study, in a classroom with laboratories, or in conjunction with a kit for experiment or demonstration. Topics covered include basic acoustics, human perception and sound, sound intensity and related concepts, fundamentals of passive noise- control strategies, basics of digital systems and adaptive controllers, and active noise control systems.
Download or read book Solutions to Example Problems in Engineering Noise Control written by Colin H. Hansen and published by Causal Systems. This book was released on 2003 with total page 115 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is the solution manual for Problems in Engineering Noise Control by the same author. The solutions are very detailed and comprehensive and extend a number of concepts with approximately 270 problems which have a total of 650 separate parts.
Download or read book Computational Science and Its Applications ICCSA 2003 written by Vipin Kumar and published by Springer. This book was released on 2003-08-03 with total page 976 pages. Available in PDF, EPUB and Kindle. Book excerpt: The three-volume set, LNCS 2667, LNCS 2668, and LNCS 2669, constitutes the refereed proceedings of the International Conference on Computational Science and Its Applications, ICCSA 2003, held in Montreal, Canada, in May 2003.The three volumes present more than 300 papers and span the whole range of computational science from foundational issues in computer science and mathematics to advanced applications in virtually all sciences making use of computational techniques. The proceedings give a unique account of recent results in computational science.
Download or read book Advances in Inverse Problems for Partial Differential Equations written by Dinh-Liem Nguyen and published by American Mathematical Society. This book was released on 2023-04-12 with total page 218 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume contains the proceedings of two AMS Special Sessions “Recent Developments on Analysis and Computation for Inverse Problems for PDEs,” virtually held on March 13–14, 2021, and “Recent Advances in Inverse Problems for Partial Differential Equations,” virtually held on October 23–24, 2021. The papers in this volume focus on new results on numerical methods for various inverse problems arising in electrical impedance tomography, inverse scattering in radar and optics problems, reconstruction of initial conditions, control of acoustic fields, and stock price forecasting. The authors studied iterative and non-iterative approaches such as optimization-based, globally convergent, sampling, and machine learning-based methods. The volume provides an interesting source on advances in computational inverse problems for partial differential equations.
Download or read book Understanding Active Noise Cancellation written by Colin N. Hansen and published by CRC Press. This book was released on 2002-05-03 with total page 173 pages. Available in PDF, EPUB and Kindle. Book excerpt: Understanding Active Noise Cancellation Provides a concise introduction to the fundamentals and applications of active control of vibration and sound for the non-expert. It is also a useful quick reference for the specialist engineer. The book emphasises the practical applications of technology, and complex control algorithms and structures are only discussed to the extent that they aid understanding. Extensive recommendations for further reading on the subject are provided, but the text will stand alone for those seeking an overview of the key issues: fundamentals, control systems, transducers, applications and possible future directions.
Download or read book Active Control of Noise and Vibration written by Colin Hansen and published by CRC Press. This book was released on 1996-11-21 with total page 1292 pages. Available in PDF, EPUB and Kindle. Book excerpt: This major work is the first to treat the active control of both sound and vibration in a unified way. It outlines the fundamental concepts, explains how a reliable and stable system can be designed and implemented, and details the pitfalls . It covers sound in ducts, sound radiation, sound transmission into enclosures, structural vibration and isolation, electronic control system design, and sensors and actuators.
Download or read book Active Noise Control written by Giora Rosenhouse and published by Witpress. This book was released on 2001 with total page 436 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book will give a physical insight into the modern field of active sound and vibration control. It will present the latest technology and achievements. The approach is generally design orientated and has a viewpoint different to other publications.
Download or read book Noise Controlling Casings written by Marek Pawelczyk and published by CRC Press. This book was released on 2022-07-28 with total page 279 pages. Available in PDF, EPUB and Kindle. Book excerpt: Noise-Controlling Casings offers a range of feasible noise-controlling strategies for different kinds of devices generating excessive noise. Depending on the required performance and the availability of energy sources, three solution categories are presented: passive (no external energy is needed, but performance is limited), semi-active (little energy is needed, but performance achieves higher values) and active (best performance, but an external energy source is needed). Two very important benefits of these proposed solutions are global noise reduction (in an entire enclosure or the surrounding space) and compact technology (contrary to other active noise control solutions requiring a large number of secondary sources and distributed sensors). Many of the solutions presented are original approaches by the authors, their own developed concepts and new elements and designs that have gained recognition in prestigious journals. The book provides a theoretical background to the research, looking at system configurations, mathematical modelling, signal processing implementation and numerical analysis. The proposed ideas can be applied to any devices provided they have casings of thin walls or they can be enclosed by casings of thin walls. Applications include industrial devices, household appliances, vehicle or aircraft cabins and more. This book will be of interest to professionals and students in the fields of acoustics, vibration, signal processing, control, automotive and aircraft engineering.
Download or read book Noise Control written by Colin H. Hansen and published by CRC Press. This book was released on 2018-09-03 with total page 438 pages. Available in PDF, EPUB and Kindle. Book excerpt: Noise Control: From Concept to Application presents the basic principles of noise control and their practical application to real problems. Numerous examples are worked out in detail and are used to illustrate the concepts in the book. There are few derivations of equations, but reference is made to texts from which these are derived. An excellent learning tool for students and practitioners, this guide to noise control will enable readers to use their knowledge to solve a wide range of industrial noise control problems. Working from basic scientific principles, the author shows how an understanding of sound can be applied to real-world settings.
Download or read book Engineering Noise Control written by David A. Bies and published by CRC Press. This book was released on 2003-07-31 with total page 745 pages. Available in PDF, EPUB and Kindle. Book excerpt: The third edition of Engineering Noise Control has been thoroughly revised, updated and extended. Each chapter contains new material, much of which is not available elsewhere. The result is a comprehensive discussion of the theoretical principles and concepts of acoustics and noise control, a detailed discussion of the hearing mechanism, noise measuring instrumentation and techniques, noise criteria, sound source characterization and emission, outdoor sound propagation, sound in rooms, sound transmission through partitions, enclosure design, dissipative and reactive mufflers, vibration isolation, equipment sound power emission calculations and active noise cancellation. The book is an excellent text for advanced undergraduate or graduate students of acoustic and noise control, and it also contains essential information and prediction techniques that make it an invaluable resource for the practitioner.
Download or read book Active Control of Sound written by P. A. Nelson and published by . This book was released on 1993 with total page 456 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book describes modern techniques for reducing the level of airborne noise through the introduction of sound radiated by additional secondary sources, bringing together the results of contemporary research in this area. It is the combination of the physical properties of sound fields and modern digital signal processing technology that has made the active control of sound a practical proposition in a number of important applications. The book covers both these aspects of the subject, initially at a fundamental level, and then in detail in later chapters. The structure of the book is such that it should be suitable for both those seeking a basic understanding of the subject and as a reference for researchers in the field. A key feature of the work is the unified presentation of material from the two disciplines of acoustics and signal processing.
Download or read book Noise Control Reduction and Cancellation Solutions in Engineering written by Daniela Siano and published by BoD – Books on Demand. This book was released on 2012-03-02 with total page 312 pages. Available in PDF, EPUB and Kindle. Book excerpt: Noise has various effects on comfort, performance, and human health. For this reason, noise control plays an increasingly central role in the development of modern industrial and engineering applications. Nowadays, the noise control problem excites and attracts the attention of a great number of scientists in different disciplines. Indeed, noise control has a wide variety of applications in manufacturing, industrial operations, and consumer products. The main purpose of this book, organized in 13 chapters, is to present a comprehensive overview of recent advances in noise control and its applications in different research fields. The authors provide a range of practical applications of current and past noise control strategies in different real engineering problems. It is well addressed to researchers and engineers who have specific knowledge in acoustic problems. I would like to thank all the authors who accepted my invitation and agreed to share their work and experiences.
