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Simulated and laboratory models of aircraft sound transmissionThomas, Ashwin Paul 27 August 2014 (has links)
With increased exposure to transportation noise, there have been continued efforts to help insulate homes from aircraft noise. Current aircraft noise guidelines are based primarily on outdoor sound levels. As people spend the majority of their time indoors, however, human perception is evidently more related to indoor sound levels. Investigations are being made to provide further insight into how typical residential constructions affect indoor response. A pilot study has built a single-room "test house", according to typical construction for mixed-humid climate regions, and has directly measured outdoor-to-indoor transmission of sound - with specific focus on continuous commercial aircraft signatures. The results of this study are being used to validate and improve modelling software that simulates a wide range of construction types and configurations for other US climate regions. The improved models will allow for increased flexibility in simulating the impacts of acoustic and energy retrofits. Overall, the project intends to improve the ability to predict acoustic performance for typical US construction types as well as for any possible design alterations for sound insulation.
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Short-time Multichannel Noise Power Spectral Density Estimators for Acoustic SignalsBlanchette, Jonathan 30 April 2014 (has links)
The estimation of power spectral densities is a critical step in many speech enhancement algorithms. The demand for multi-channel speech enhancement systems is high with applications in teleconferencing, cellular phones, and hearing aids. The first objective of the thesis is to develop a general multi-channel framework to solve for the diffuse noise power spectral densities whenever the spatial correlation or coherence matrix is pre-estimated and the number of speakers is less than the number of microphones. The second objective is to develop closed-form analytical solutions. The performance of the developed algorithms is evaluated with pre-existing algorithms using prescribed performance measures.
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Identifiering och kartläggning av buller i centrala Falun / Identification and mapping of noise pollution in central FalunSarhatlić, Nerim January 2014 (has links)
Ett problem i dagens moderna samhälle är att bullernivåerna är för höga. Dessa höga bullernivåer är en hälsorisk och kan ge människan permanenta skador. Buller är något som inte får försummas. Syftet med examensarbetet är att identifiera och kartlägga bullret på Holmgatan i centrala Falun. Syftet är också att analysera resultatet och sätta det i förhållande till myndigheternas krav och riktlinjer avseende bullernivåer. Examensarbetet avgränsas till bullermätning och kartläggning på delar av Holmgatan i centrala Falun, som bedömts vara extra utsatta för buller. Bullermätningarna utfördes under fyra vardagar och under tider från det att de flesta affärer öppnar till att de stänger, kl. 10-18. Metoden bestod utav bullermätningar som utfördes med en timmes intervall längs den utvalda delen av Holmgatan. Dagarna då dessa mätningar utfördes var 2/12 till 5/12-2013. Resultatet redovisas som medelvärdet per timme av alla dagar då bullermätningarna utfördes. Resultatet varierade, det lägsta bullermedelvärdet var 57 dB och det högsta bullermedelvärdet var 83 dB. Det syns tydligt att de högre värdena ligger närmare en gata som används av bussar och andra transportfordon. De lägre värdena låg oftast i närheten av Geislerka parken, som är en stor och öppen yta mitt i Holmgatan. Över lag så låg bullermedelvärdena mellan 60-65 dB. Slutsatsen tyder på att bullernivån på Holmgatan överskrider inte myndigheternas krav på vad som anses som skadligt men ligger strax under riktlinjerna för maximalnivån för utomhusbuller (70 dB). Åtgärder såsom att plantera vegitation på fasader och omleda trafiken skulle kunna vidtas för att minska bullernivån på Holmgatan. / A problem in today's modern society is that the noise levels are too high. These high levels of noise is a health hazard and can give man permanent damage. Noise pollution is something that must not be neglected. The purpose of this study is to identify and map the noise on Holmgatan in central Falun. The purpose is also to analyze the results and put them in relation with the regulatory requirements and guidelines regarding noise levels and to analyze the results and see if actions should be taken against the noise on Holmgatan. The thesis is limited to noise measurements and mapping of parts of Holmgatan, considered to be especially vulnerable to noise. Noise measurements were conducted during four weekdays and during times from when most stores open to most of them then closing, at. 10-18. The method consisted of noise measurements which were performed at hourly intervals along the selected portion of Holmgatan. The days on which these measurements were performed was from 2/12 to 5/12-2013. The results are reported as average value per hour of any day on which noise measurements were made. The results varied, the lowest average noise was 57 dB and the highest average noise was 83 dB. It is clearly seen that the higher values are closer to a street used by buses and other transport vehicles. The lower values were generally near Geislerka parken, which is a large garden, an open area in the middle of Holmgatan. Overall, the average noise values were between 60-65 dB. The conclusion suggests that the noise level at Holmgatan do not exceed regulatory requirements on what is considered as harmful but it is just below the guidelines for the maximum level of outdoor noise (70 dB). Actions such as planting vegetation on the facades and to redirect the traffic could be done to reduce noise levels at Holmgatan.
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Metastability of Morse-Smale dynamical systems perturbed by heavy-tailed Lévy type noiseMichael Högele, Ilya Pavlyukevich January 2014 (has links)
We consider a general class of finite dimensional deterministic dynamical systems with finitely many local attractors each of which supports a unique ergodic probability measure, which includes in particular the class of Morse–Smale systems in any finite dimension. The dynamical system is perturbed by a multiplicative non-Gaussian heavytailed Lévy type noise of small intensity
ε > 0. Specifically we consider perturbations leading to a Itô, Stratonovich and canonical (Marcus) stochastic differential equation. The respective asymptotic first exit time and location problem from each of the domains
of attractions in case of inward pointing vector fields in the limit of ε-> 0 has been investigated by the authors. We extend these results to domains with characteristic boundaries and show that the perturbed system exhibits a metastable behavior in the sense that there exits a unique ε-dependent time scale on which the random system converges to a continuous time Markov chain switching between the invariant measures. As examples we consider α-stable perturbations of the Duffing equation and a chemical system exhibiting a birhythmic behavior.
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Development and validation of a laminate flooring system sound quality test methodWilson, James Harris 19 May 2009 (has links)
Laminate flooring manufacturers have received negative feedback from customers on the sound quality of laminate flooring installations. Customers express a preference for the sound of traditional hardwood floors over that of laminate flooring composites. Consumers notice a difference between the sounds created by a footfall between laminate flooring and hardwood flooring. They perceive the laminate flooring sound of a footfall to be annoying and associate it to the flooring being of a lower quality. No objective test procedure exists to validate
the marketing claims of the performance of these products. The objective of the work in this thesis is to develop a test method that evaluates the human perception of the sound quality of footfall noise on laminate flooring
composites.
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A study of the production, character, and abatement of noise in pneumatic percussive drills.Beiers, John Leonard. Unknown Date (has links)
No description available.
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A study of the production, character, and abatement of noise in pneumatic percussive drills.Beiers, John Leonard. Unknown Date (has links)
No description available.
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A study of the production, character, and abatement of noise in pneumatic percussive drills.Beiers, John Leonard. Unknown Date (has links)
No description available.
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A study of the production, character, and abatement of noise in pneumatic percussive drills.Beiers, John Leonard. Unknown Date (has links)
No description available.
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Recycled aggregate concrete acoustic barrierKrezel, Zbigniew Adam. January 2006 (has links)
Thesis (PhD) - Swinburne University of Technology, 2006. / Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Civil Engineering, Swinburne University of Technology - 2006. Typescript. Includes bibliographical references.
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