The principal concern of this paper is the valuation of the impact of aircraft noise associated with Vancouver International Airport on residents living close to the flight paths. In surveying previous research relevant to the valuation of the impact of airport noise, the paper selects a property value approach in which the residential property market is used as a surrogate for airport noise nuisance (on the premise that noisier areas will have lower house prices than quieter areas, ceteris paribus). The selected approach involves undertaking hedonic price modelling in which multiple regression is used to estimate property value, and from which the value of one attribute, exposure to airport noise, may be obtained implicitly. Noise is measured by the Noise Exposure Forecast (NEF) technique, a widely used procedure for measuring airport noise. Several theoretical concerns with the approach are addressed before reviewing the results of previous airport noise studies which use hedonic price models. The results of these models may be reported in terms of noise-property value relationships, measured by a noise depreciation sensitivity index (NDSI). If the functional form of noise is linear against the natural logarithm of property value, the NDSI will equal the value of the noise coefficient and will be constant regardless of the absolute price of the property. The NDSI figures for previous studies range from about 0.40 to 1.10 percent per decibel for 1967 to 1976 data, with a simple average of about 0.61 percent. Of the two general model types reported, the one involving individual property sales data is considered superior to that using only census information. The model designed for this study uses individual price data for 1987 single-detached property sales in the Township of Richmond (where the majority of noise-affected properties are situated). Data for physical, area, public sector, accessibility and other characteristics are obtained from various sources to enable the modelling of some 1539 sales. Two data sets are tested with 44 variables initially collected for each: one set involving only those properties inside the NEF 25 noise zone (assumed to be affected by airport noise), the other involving all properties. For each data set alternative functional forms are tested, as are several approaches for explaining noise (continuous or dummy variables, and different assumed thresholds). Of the eleven models reported, the preferred model includes only those single-detached properties exposed to NEF 25 or higher where the natural log of sales price is regressed against sixteen independent variables including a continuous form of the noise variable (NEF level) The model has an adjusted R2 value of .634, and a noise coefficient of -.006484 - implying a one unit increase in noise results in more than half of a percent decrease in property price (NDSI equals 0.65). The 95 percent confidence interval for this variable is -.0097 to -.0033. Preliminary analysis of the model type using census data is also reported. Certain matters of interpretation are discussed before attempting a preliminary application in the setting of Vancouver International Airport in which the noise impact of a third runway is indicated. What distinguishes the modelling for Vancouver International Airport from the previous studies is the high quality of individual data, the large sample size, the testing of several forms for the noise variable(s) and the exploration of alternative noise thresholds. Notwithstanding this, the study concludes by outlining several areas for further research. / Business, Sauder School of / Graduate

The purpose of this study was to investigate the feasibility of measuring the insertion loss (attenuation) provided by cannon earplugs using the Knowles Electronics Manikin for Acoustic Research. Five earplugs were tested in a 90 dB sound field at discrete frequencies matching those published by NIOSH. Each plug was exposed to 10 trials. Results indicate an approximation between values obtained in the study and NICSH published values. Some consistent differences tend to indicate that NIOSH values may overrate low frequency attenuation.

Recently, researchers have attempted to increase the time efficiency of the smartphone DIN test by decreasing the number of presentations of the DIN. One suggestion was to use a variable step size based on the correctness of digits identified within the triplet. In contrast, another suggested using a fixed signal-to-noise ratio (SNR) presentation level for all presentations of the DIN test and producing a pass/fail result based on whether a 95% recognition level was reached. This study aimed to compare three novel DIN test procedures as a potential way to improve efficiency with acceptable reliability using smartphone technology. / Dissertation (MA (Audiology) )--University of Pretoria, 2021. / Speech-Language Pathology and Audiology / MA (Audiology) / Unrestricted

The noise in the Langmuir Probe and Plasma Wave Instrument (LP-PWI) on board ESA:s future Jupiter satellite JUICE (Jupiter ICy Moons Explorer) was investigated. Thermal Johnson-Nyquist noise and shot noise, caused by fluctuations in the probe-plasma currents, were combined with the quasi-thermal noise (QTN) due to thermal fluctuations in the electric field in the plasma, using a small signal equivalent circuit model. The contributions and effects of each of the considered noise sources were examined and compared for a number of representative space plasma conditions, including the cold dense plasma of Ganymede's ionosphere and the hot tenuous plasma out in the Jovian magnetosphere. The results showed that in the cold dense plasma of Ganymede's ionosphere, the antenna was long compared to the Debye length and the quasi-thermal noise had a clearly pronounced peak and a steep high-frequency cut-off. For an antenna biased to 1 V with respect to the plasma, the shot noise due to the ambient plasma was the dominant source of noise. For a an antenna at the floating potential the photoelectron shot noise coalesced with the shot and Nyquist noises of the ambient plasma to form almost a single curve. In the hot tenuous plasma out in Jupiter's magnetosphere, the antenna was short compared to the Debye length and the QTN spectrum was much flatter, with little or no peak at the plasma frequency and a very weak high-frequency cut-off. For an antenna biased to 1 V, the shot noise due to photoelectron emission dominated at Callisto's orbital position whereas at Ganymede's and Europa's orbital positions the Nyquist and shot noises of the ambient plasma particles were the dominant noise components. For an antenna at the floating potential, the shot and Nyquist noises of the ambient plasma also dominated the output noise, except at Europa's orbital position, where the quasi-thermal noise was the largest noise component for frequencies at and above the plasma frequency. The numerical calculations were performed using MATLAB. The code was made available in a Git repository at https://github.com/eliasodelstad/irfuproj_JUICE_noise.

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This report explains the development of a sound measuring system for continuous monitoring of sound levels. Dedicated telephone lines are used for data transmission so that sound level data can be monitored at installations far from the area of concern. This allows the sound sensing equipment to be left unattended and thereby greatly reduces the manpower costs of operation. That predetermined data conditions can be detected when they occur and corrective action can be taken immediately at the data receiving installation further justifies the method used. Background information and general need for such a system are discussed. Growing public concern with noise is creating a demand for more and better sound measurement devices and for more control of unnecessary noises. For description, the system is divided into functional sections. The sections are described and design considerations are given in order of data flow starting with the sound sensing devise, or microphone, and ending with the warning system which alerts the operator when a predetermined signal level has been exceeded. Circuits to detect selected conditional of excess sound and to control the alarm to these conditions are included.

Yes / In the past it has been found that the maximum pass-by noise for the most noisy of vehicles can be 6-8 dB(A) above the average for the sample. It is therefore useful to consider the types of vehicle that make excessive noise and their condition and to reach some conclusions on how best to reduce the problem. Measurements of maximum noise, pass-by speed together with video footage were taken on a busy dual carriageway road (A34) in the UK carrying a high percentage of heavy vehicles. The intention was to collect sufficient information on light, medium heavy and heavy vehicles to enable typical characteristics of noisy vehicles to be identified. Peak noise levels produced by vehicles under normal operating conditions of steady speed were recorded and not of vehicle being driven in an aggressive manner e.g. under harsh acceleration. This paper reports on the characteristics of excessively noisy vehicles that were identified under these cruising conditions in free flow traffic conditions. / The work described in this report was carried out in the Noise and Vibration Team of TRL Limited under funding from the Transport Research Foundation.

Phase noise from radio frequency (RF) oscillators is one of the major limiting factors affecting communication system performance. Phase noise directly effects short-term frequency stability, Bit-Error-Rate (BER), and phase-locked loop adjacent-channel interference. RF oscillator circuits contain at least one active device, usually a transistor. The active device has noise properties which generally dominate the noise characteristic limits of an oscillator. Since all noise sources, except thermal noise, are generally proportional to average current flow through the active device, it is logical that reducing the current flow through the device will lead to lower noise levels. A theory based on the time-varying properties of oscillators proposes that narrowing the current pulse width in the active device will decrease the time that noise is present in the circuit and therefore, decrease phase noise even further. The time-domain waveforms and phase noise of an active-biased 700MHz oscillator are analyzed, showing heavy saturation and high harmonic content. Redesigns of the example oscillator in active-bias and four-resistor-bias configurations show improved phase noise and lower harmonic levels at the output. Five oscillator designs of each bias configuration, each having a different pulse width, are simulated. As predicted by the theory, the narrowest current pulse corresponds to the lowest phase noise of the simulated oscillators. / Master of Science

The issues and concerns facing recreation managers, academicians, and other practitioners are now often complex and important enough that solving them requires more than the sum of parts from social and physical disciplines. To that end, this dissertation document identifies and addresses three research projects that in varying proportions draw from the social and ecological aspects of recreation management. The first of three articles in this dissertation examined approximation of cross sectional soil profiles on foot trails. Monitoring this ecological indicator with current field techniques can be expensive and time-consuming for managers. Therefore, this article described a modified procedure for assessing trail soil loss and discusses several potentially useful geometric curves for approximating the cross-section of a trail at a given sampling point and in aggregate across a trail network. Differences in profiles for each study area and implications for inventorying and monitoring were discussed. The second article examined integration of soundscape and hiker spatial modeling. GPS data were used to generate a spatial model of hiker travel, soundscape modeling software calibrated with field data was used to generate a spatial model of sound, and the models were integrated in a geographic information system to provide insights for baseline and an alternative management option scenario. The findings suggested that small changes in soundscape, based on altered management practices, can have large effects on visitors' hiking experiences in terms of soundscape. The third article discussed an observational study examining several integrative and additive, information/education and site management approaches to preventing natural resource damage along backcountry trails. Video surveillance equipment unobtrusively captured hiker behaviors within the study area for each treatment. The findings suggested that direct, obtrusive measures (e.g., low symbolic rope fencing) in some cases can outperform multiple concurrent measures that are less direct and/or obtrusive. Implications on aesthetics, experiences, and management decision-making were discussed. / Ph. D.