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Colin H. Hansen

Bio: Colin H. Hansen is an academic researcher from University of Adelaide. The author has contributed to research in topics: Noise & Active noise control. The author has an hindex of 38, co-authored 290 publications receiving 6089 citations. Previous affiliations of Colin H. Hansen include BBN Technologies & Japanese Ministry of International Trade and Industry.


Papers
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Book
29 Sep 2003
TL;DR: In this paper, the authors describe the human ear's physical properties of the central partition of the Central Partition of Noise Induced Hearing Loss Subjective Response to Sound Pressure Level Instrumentation for Noise Measurement and Analysis Microphones Weighting Networks Sound Level Meters Classes of Sound Level Meter Sound Level meter Calibration Noise Measurements Using Sound Level Measurement Data Loggers Personal Sound Exposure Meter Recording of Noise Spectrum Analysers Intensity Meter Energy Density Sensors Sound Source Localization Criteria Introduction Hearing Loss Hearing Damage Risk Hearing Damage risk Criteria Implementing a Hearing Conservation
Abstract: Fundamentals and Basic Terminology Introduction Noise-Control Strategies Acoustic Field Variables Wave Equations Mean Square Quantities Energy Density Sound Density Sound Power Units Spectra Combining Sound Pressures Impedance Flow Resistance The Human Ear Brief Description of the Ear Mechanical Properties of the Central Partition Noise Induced Hearing Loss Subjective Response to Sound Pressure Level Instrumentation for Noise Measurement and Analysis Microphones Weighting Networks Sound Level Meters Classes of Sound Level Meter Sound Level Meter Calibration Noise Measurements Using Sound Level Meters Time-Varying Sound Noise Level Measurement Data Loggers Personal Sound Exposure Meter Recording of Noise Spectrum Analysers Intensity Meter Energy Density Sensors Sound Source Localization Criteria Introduction Hearing Loss Hearing Damage Risk Hearing Damage Risk Criteria Implementing a Hearing Conservation Program Speech Interference Criteria Psychological Effects of Noise Ambient Noise Level Specification Environmental Noise Level Criteria Environmental Noise Level Surveys Sound Sources and Outdoor Sound Propagation Introduction Simple Source Dipole Source Quadruple Source (Far-Field Approximation) Line Source Piston in an Infinite Baffle Incoherent Plane Radiator Directivity Reflection Effects Reflection and Transmission at a Plane/Two Media Interface Sound Propagation Outdoors, General Concepts Sound Power, its Use and Measurement Introduction Radiation Impedance Relation between Sound Power and Sound Pressure Radiation Field of a Sound Source Determination of Sound Power Using Intensity Measurements Determination of Sound Power Using Surface Vibration Measurements Some Uses of Sound Power Information Sound in Enclosed Spaces Introduction Low Frequencies Bound between Low-Frequency and High-Frequency Behavior High Frequencies, Statistical Analysis Transit Response Porous Sound Absorbers Panel Sound Absorbers Flat and Long Rooms Applications of Sound Absorption Auditorium Design Partitions, Enclosures and Barriers Introduction Sound Transmission through Partitions Noise Reduction vs Transmission Loss Enclosures Barriers Pipe Lagging Muffling Devices Introduction Measures of Performance Diffusers as Muffling Devices Classification of Muffling Devices Acoustic Impedance Lumped Element Devices Reactive Devices Lined Ducts Duct Bends or Elbows Unlined Ducts Effect of Duct End Reflections Duct Break-Out Noise Line Plenum Attenuator Water Injection Directivity of Exhaust Duct Vibration Control Introduction Vibration Isolation Types of Isolators Vibration Absorbers Vibration Neutralizers Vibration Measurement Damping of Vibrating Surfaces Measurement of Damping Sound Power and Sound Pressure Level Estimation Procedures Introduction Fan Noise Air Compressors Compressors for Chillers and Refrigeration Units Cooling Towers Pumps Jets Control Valves Pipe Flow Boilers Turbines Diesel and Gas-Driven Engines Furnace Noise Electric Motors Generators Transformers Gears Transportation Noise Practical Numerical Acoustics Introduction Low-Frequency Region High-Frequency Region: Statistical Energy ANalysis

548 citations

Book
15 Nov 1996
TL;DR: In this article, the authors present a review of acoustics and vibration in modern control systems, including feedback control of flexable structures described in terms of modes, and a few electronic implementation issues.
Abstract: Background. Fundamentals of acoustics and vibration. Spectral analysis. Modal analysis. Modern control review. Feedforward control system design. Active control of noise propagating in ducts. Active control of free field sound radiation. Active control of enclosed sound fields. Feedforward control of vibration in beams and plates. Feedback control of flexable structures described in terms of modes. Vibration isolation. A few electronic implementation issues. Sound sources and sound sensors. Vibration sensors and vibration sources. Appendix.

534 citations

Journal ArticleDOI
TL;DR: In this paper, the measurement and use of flow resistance information for the calculation of the acoustical properties of porous materials has been examined, and it has been demonstrated that flow resistance provides a description of a porous material which is sufficient to characterise its acoustic performance for all common applications.

223 citations

Book
01 Dec 1995
TL;DR: In this article, the authors present a comprehensive and authoritative student textbook that covers the fundamentals of acoustics, theoretical concepts and practical application of current noise control technology, which can be used to solve real world problems encountered by noise and vibration consultants as well as the more straightforward ones handled by engineers and occupational hygienists in industry.
Abstract: This classic and authoritative student textbook contains information that is not over simplified and can be used to solve the real world problems encountered by noise and vibration consultants as well as the more straightforward ones handled by engineers and occupational hygienists in industry. The book covers the fundamentals of acoustics, theoretical concepts and practical application of current noise control technology. It aims to be as comprehensive as possible while still covering important concepts in sufficient detail to engender a deep understanding of the foundations upon which noise control technology is built. Topics which are extensively developed or overhauled from the fourth edition include sound propagation outdoors, amplitude modulation, hearing protection, frequency analysis, muffling devices (including 4-pole analysis and self noise), sound transmission through partitions, finite element analysis, statistical energy analysis and transportation noise. For those who are already well versed in the art and science of noise control, the book will provide an extremely useful reference. A wide range of example problems that are linked to noise control practice are available on www.causalsystems.com for free download.

198 citations

Journal ArticleDOI
TL;DR: This correspondence considers the effect of errors in this estimate of the cancellation path transfer function on the stability of the algorithm implemented in the time domain, concluding that while a maximum phase error of /spl plusmn/90/spl deg/ is a bound for stability, there is no simple relationship between error and stability within this region.
Abstract: The filtered-x LMS algorithm, which is commonly implemented in active noise and vibration control systems, requires an estimate of the cancellation path transfer function to maintain algorithm stability. This correspondence considers the effect of errors in this estimate on the stability of the algorithm implemented in the time domain, concluding that while a maximum phase error of /spl plusmn/90/spl deg/ is a bound for stability, there is no simple relationship between error and stability within this region. >

167 citations


Cited by
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Journal ArticleDOI

[...]

08 Dec 2001-BMJ
TL;DR: There is, I think, something ethereal about i —the square root of minus one, which seems an odd beast at that time—an intruder hovering on the edge of reality.
Abstract: There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality. Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

33,785 citations

Book
01 Jan 1996
TL;DR: In this article, the authors present a review of rigor properties of low-dimensional models and their applications in the field of fluid mechanics. But they do not consider the effects of random perturbation on models.
Abstract: Preface Part I. Turbulence: 1. Introduction 2. Coherent structures 3. Proper orthogonal decomposition 4. Galerkin projection Part II. Dynamical Systems: 5. Qualitative theory 6. Symmetry 7. One-dimensional 'turbulence' 8. Randomly perturbed systems Part III. 9. Low-dimensional Models: 10. Behaviour of the models Part IV. Other Applications and Related Work: 11. Some other fluid problems 12. Review: prospects for rigor Bibliography.

2,920 citations

Journal ArticleDOI
01 Jun 1999
TL;DR: The basic adaptive algorithm for ANC is developed and analyzed based on single-channel broad-band feedforward control, then modified for narrow-bandFeedforward and adaptive feedback control, which are expanded to multiple-channel cases.
Abstract: Active noise control (ANC) is achieved by introducing a cancelling "antinoise" wave through an appropriate array of secondary sources. These secondary sources are interconnected through an electronic system using a specific signal processing algorithm for the particular cancellation scheme. ANC has application to a wide variety of problems in manufacturing, industrial operations, and consumer products. The emphasis of this paper is on the practical aspects of ANC systems in terms of adaptive signal processing and digital signal processing (DSP) implementation for real-world applications. In this paper, the basic adaptive algorithm for ANC is developed and analyzed based on single-channel broad-band feedforward control. This algorithm is then modified for narrow-band feedforward and adaptive feedback control. In turn, these single-channel ANC algorithms are expanded to multiple-channel cases. Various online secondary-path modeling techniques and special adaptive algorithms, such as lattice, frequency-domain, subband, and recursive-least-squares, are also introduced. Applications of these techniques to actual problems are highlighted by several examples.

1,254 citations

Journal ArticleDOI
TL;DR: The importance of having a clear understanding of the principles behind both the acoustics and the electrical control in order to appreciate the advantages and limitations of active noise control is emphasized.
Abstract: Active noise control exploits the long wavelengths associated with low frequency sound. It works on the principle of destructive interference between the sound fields generated by the original primary sound source and that due to other secondary sources, acoustic outputs of which can be controlled. The acoustic objectives of different active noise control systems and the electrical control methodologies that are used to achieve these objectives are examined. The importance of having a clear understanding of the principles behind both the acoustics and the electrical control in order to appreciate the advantages and limitations of active noise control is emphasized. A brief discussion of the physical basis of active sound control that concentrates on three-dimensional sound fields is presented. >

965 citations

Journal ArticleDOI
B.B. Bauer1
01 Apr 1963

897 citations