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Title: Effects of urban morphology on urban sound environment from the perspective of masking effects
Author: Hao, Yiying
ISNI:       0000 0004 5350 5248
Awarding Body: University of Sheffield
Current Institution: University of Sheffield
Date of Award: 2014
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This study explores how to improve soundscape quality in the context of urban morphology from the perspective of masking effects. Masking in this study is explained as a hearing phenomenon by which soundscape characteristics are altered by the presence of interfering sound event(s). The concept of this study is primarily based on two hypothesises: first, masking effects in soundscape can influence the perception and evaluation of sound environment; second, urban sound propagation has relationships with urban morphological parameters. Diverse sounds from the common urban sound sources are characterised, using acoustic analysis and psychological evaluation, with a consideration of potential masking among them. The masking effects of traffic noise by birdsong are then investigated, showing the differences in the psychological evaluation on the traffic noise environment under different physical conditions, with maximum score differences of 3.9 in the Naturalness, 3.1 in the Annoyance, and 4.0 in the Pleasantness in a scale of 0-10. In view of the results in the psychological evaluation, two main research directions are confirmed, including urban noise attenuation (car traffic and flyover aircraft) and natural sound enhancement (birdsong loudness and the visibility of green areas). The relationships between spatial sound levels and quantitative urban morphological parameters are explored by noise mapping technique and a MATLAB program on spatial sound level matrix. For the traffic noise, it is possible to achieve noise level attenuation of more than 10 dB and reduction of 25% noisy area through the control of the parameters, e.g., the Building Plan Area Fraction, the Complete Aspect Ratio, the Building Frontal Area Index, and the Horizontal Distance of First-row Building to Road. For the flyover aircraft noise, a decrease in the Horizontal Distance of First-row Building to Flight Path can result in more than 10 dB noise reduction. For the birdsong, with an increasing Green Area Perimeter, the sound levels in the areas further from the green areas can be increased by up to 11 dB; with an increasing Green Area Dispersion Index, the sound levels can increase by approximately 10 dB. Meanwhile, a site with a lower Building Plan Area Fraction has higher visibility of the green areas, with an increase of Mean Visibility of approximately 600.
Supervisor: Kang, Jian ; Heinrich, Woertche Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available