Thesis (M.S.)--Ohio University, November, 2000. / Title from PDF t.p.

Thesis (M.S.)--Ohio University, June, 2003. / Title from PDF t.p. Includes bibliographical references (leaves 66).

Thesis (M. Sc.)--University of Hong Kong, 1998. / Includes bibliographical references (leaf 86-87).

No / The paper describes model testing of the acoustic performance of vertically louvred and the corresponding predicted performance using a modified Boundary Element Method (BEM) program. The program was developed in a previous phase of the Transport Research Laboratory's research into the performance of modified barriers. Measurements on 1/20th scale model barriers were carried out in a semi-anechoic chamber designed primarily for scale model experiments to investigate outdoor sound propagation under controlled conditions. It was concluded from measurements in the scale model facility that the modified BEM code provided an adequate description of the leakage of sound through louvred barriers. The program was subsequently used to examine the performance of various designs of barrier in order to identify likely cost effective designs.

This work undertook the examination of the perceived barriers that exist to the management of occupational noise exposure in the workplace. Exposure to excessive levels of noise results in cumulative damage to the hearing mechanism of the ear and a subsequent hearing loss. This hearing loss is permanent and does not recover over time. Initially the conventional method of addressing or controlling noise exposure was through Hearing Conservation Programs and more recently through Occupational Noise Management Programs that take more of a risk management approach. However, the numbers of new hearing loss claims submitted through the various ???workcover??? and ???worksafe??? authorities in Australia continue to remain very high. Hearing loss claims rank within the top two in number of new claims each year. The research conducted shows that there are four main barriers perceived by individuals that work against the institution of effective preventive action. These four main barriers in order of priority are hearing protectors, information, culture and management, and are themselves each composed of several lesser factors. Each of the barriers was examined more closely in an attempt to better understand how they operate and the potential to discover how they may be overcome. To briefly summarise the main barriers: 1) Hearing protectors are uncomfortable, impede communication and are unpleasant to wear; 2) Individuals would like more information on noise reduction and for this information to be supplied by management; 3) workplace and management culture needs to be supportive of occupational health and safety in general and with the implementation of supportive preventive measures in particular; and 3) management needs to be seen to place importance on occupational health and safety in the workplace in general and the reduction of excessive noise in particular. By being aware of the barriers and operation the design of future more effective intervention or better noise management programs should be possible.

This work undertook the examination of the perceived barriers that exist to the management of occupational noise exposure in the workplace. Exposure to excessive levels of noise results in cumulative damage to the hearing mechanism of the ear and a subsequent hearing loss. This hearing loss is permanent and does not recover over time. Initially the conventional method of addressing or controlling noise exposure was through Hearing Conservation Programs and more recently through Occupational Noise Management Programs that take more of a risk management approach. However, the numbers of new hearing loss claims submitted through the various ???workcover??? and ???worksafe??? authorities in Australia continue to remain very high. Hearing loss claims rank within the top two in number of new claims each year. The research conducted shows that there are four main barriers perceived by individuals that work against the institution of effective preventive action. These four main barriers in order of priority are hearing protectors, information, culture and management, and are themselves each composed of several lesser factors. Each of the barriers was examined more closely in an attempt to better understand how they operate and the potential to discover how they may be overcome. To briefly summarise the main barriers: 1) Hearing protectors are uncomfortable, impede communication and are unpleasant to wear; 2) Individuals would like more information on noise reduction and for this information to be supplied by management; 3) workplace and management culture needs to be supportive of occupational health and safety in general and with the implementation of supportive preventive measures in particular; and 3) management needs to be seen to place importance on occupational health and safety in the workplace in general and the reduction of excessive noise in particular. By being aware of the barriers and operation the design of future more effective intervention or better noise management programs should be possible.

Thesis (M.Phil.)--Hong Kong University of Science and Technology, 2005. / Includes bibliographical references. Also available in electronic version.

No description available.

A coefficient sensitivity measure for state space recursive, finite wordlength, digital filters is developed and its relationship to the filter output quantization noise power is derived. The sensitivity measure is simply the sum of the L₂ norm of all first order partials of the system function with respect to the system parameters; alternatively, the measure may be viewed as the output variance of the error system created by the inherent parameter quantization. Since the measure uses only the first order partials, it is a lower bound approximation to the output quantization noise power. During analysis, numerically unstable conditions may occur because ideal filter characteristics imply system poles which are almost on the unit circle in the z-plane; therefore, it is proposed to scale the radii of the pole and zero magnitudes. Thus, the scaled system has the same frequency information as the original system, but performs better numerically. The direct II form sensitivity, which is shown to be inversely proportional to the product of the system pole and zero distances, can be reduced by the judicious placement of added pole/zero cancellation pairs which increase the order of the system but do not change the system function. / M. Eng.

No description available.