179 resultados para White noise


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This paper proposes a self-tuning feedforward active noise control (ANC) system with online secondary path modeling. The step-size parameters of the controller and modeling filters have crucial rule on the system performance. In literature, these parameters are adjusted by trial-and-error. In other words, they are manually initialized before system starting, which require performing extensive experiments to ensure the convergence of the system. Hence there is no guarantee that the system could perform well under different situations. In the proposed method, the appropriate values for the step-sizes are obtained automatically. Computer simulation results indicate the effectiveness of the proposed method.

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As one of the measures for decreasing road traffic noise in a city, the control of the traffic flow and the physical distribution is considered. To conduct the measure effectively, the model for predicting the traffic flow in the citywide road network is necessary. In this study, the existing model named AVENUE was used as a traffic flow prediction model. The traffic flow model was integrated with the road vehicles' sound power model and the sound propagation model, and the new road traffic noise prediction model was established. As a case study, the prediction model was applied to the road network of Tsukuba city in Japan and the noise map of the city was made. To examine the calculation accuracy of the noise map, the calculated values of the noise at the main roads were compared with the measured values. As a result, it was found that there was a possibility that the high accuracy noise map of the city could be made by using the noise prediction model developed in this study.

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The classic white formal shirt is a widely and readily familiar object with considerable historical cultural significance to diverse social groups, and is therefore deserving of iconic status. For more than two hundred years, this singular item of apparel has been able to define and represent status, wealth, gender shifts and fashion norms. This garment, which has historically been relinquished to undergarment status, deserves an escalation of standing. The classic white formal shirt, for both men and women, can be used as a mirror to map considerable social change and the diversity of influence can be traced through many examples, including: Beau Brummell’s dandy status with his legendry white shirting; the Gibson Girl with her decorated white shirt style blouse defining ideals of female beauty; IBM business employees in the 1920s marketing trustworthiness through the uniformity of white shirts; the fictional advertising creation of the Arrow Collar Man, with his rigid white shirt, promoting American masculine ideals; and the iconic 1980s Hugo Boss style crisp white dress shirt symbolising power. The origins of the influence of the white shirt can be best traced in the Victorian era where it was an important symbol of wealth and class distinction and a powerful emblem of sobriety and uniformity for men. The pure white colour fulfilled masculine ideals of resolute austerity and the shirt, through its constancy, epitomised conformity and dependability. For women, the white cloth of the ‘shirt-waist’ from this period was also linked to ideals of cleanliness and purity and was seen as an iconic symbol of the new independent working class woman. This paper will propose that the classic white formal shirt, for both men and women, has been a powerful marker of social shifts in Western society and this underrated item of apparel, with limited scholarly writing, is worthy of iconic status. The discussion will trace the historical development of both the men’s and women’s white shirt, each with their own unique history, and in doing so highlight the considerable historical cultural significance associated with the white formal shirt. Discussed first will be the men’s white formal shirt.

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Circulating 25-hydroxyvitamin D (25(OH)D), a marker for vitamin D status, is associated with bone health and possibly cancers and other diseases; yet, the determinants of 25(OH)D status, particularly ultraviolet radiation (UVR) exposure, are poorly understood. Determinants of 25(OH)D were analyzed in a subcohort of 1,500 participants of the US Radiologic Technologists (USRT) Study that included whites (n 842), blacks (n 646), and people of other races/ethnicities (n 12). Participants were recruited monthly (20082009) across age, sex, race, and ambient UVR level groups. Questionnaires addressing UVR and other exposures were generally completed within 9 days of blood collection. The relation between potential determinants and 25(OH)D levels was examined through regression analysis in a random two-thirds sample and validated in the remaining one third. In the regression model for the full study population, age, race, body mass index, some seasons, hours outdoors being physically active, and vitamin D supplement use were associated with 25(OH)D levels. In whites, generally, the same factors were explanatory. In blacks, only age and vitamin D supplement use predicted 25(OH)D concentrations. In the full population, determinants accounted for 25 of circulating 25(OH)D variability, with similar correlations for subgroups. Despite detailed data on UVR and other factors near the time of blood collection, the ability to explain 25(OH)D was modest.

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A multi-faceted study is conducted with the objective of estimating the potential fiscal savings in annoyance and sleep disturbance related health costs due to providing improved building acoustic design standards. This study uses balcony acoustic treatments in response to road traffic noise as an example. The study area is the State of Queensland in Australia, where regional road traffic noise mapping data is used in conjunction with standard dose–response curves to estimate the population exposure levels. The background and the importance of using the selected road traffic noise indicators are discussed. In order to achieve the objective, correlations between the mapping indicator (LA10 (18 hour)) and the dose response curve indicators (Lden and Lnight) are established via analysis on a large database of road traffic noise measurement data. The existing noise exposure of the study area is used to estimate the fiscal reductions in health related costs through the application of simple estimations of costs per person per year per degree of annoyance or sleep disturbance. The results demonstrate that balcony acoustic treatments may provide a significant benefit towards reducing the health related costs of road traffic noise in a community.

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Urban road traffic noise in cities is an ongoing and increasing problem across much of the world. Consequently a large amount of effort is expended in attempts to address this problem, especially in the area of acoustic design of buildings. Acoustic design policies developed by government authorities will typically focus on required transport noise reductions through a building façade to meet a specified internal noise levels. The significance of balcony acoustic treatments has been highlighted in recent decades yet this area has potentially been considered less important than the need for acoustic isolation of building facades. This paper outlines recent research that has been conducted in determining the significance of balcony acoustic treatments in mitigating urban road traffic noise. It summarizes recent literature, some of which focuses on technological advances in the knowledge of balcony acoustic design and some literature discusses the overall aims and benefits of balcony acoustic design. The aim of this paper is to promote the use of balcony acoustic design as a significant element in the overall solution towards mitigating road traffic noise in modern cities.

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Balcony acoustic treatments can mitigate the effects of community road traffic noise. To further investigate, a theoretical study into the effects of balcony acoustic treatment combinations on speech interference and transmission is conducted for various street geometries. Nine different balcony types are investigated using a combined specular and diffuse reflection computer model. Diffusion in the model is calculated using the radiosity technique. The balcony types include a standard balcony with or without a ceiling and with various combinations of parapet, ceiling absorption and ceiling shield. A total of 70 balcony and street geometrical configurations are analyzed with each balcony type, resulting in 630 scenarios. In each scenario the reverberation time, speech interference level (SIL) and speech transmission index (STI) are calculated. These indicators are compared to determine trends based on the effects of propagation path, inclusion of opposite buildings and difference with a reference position outside the balcony. The results demonstrate trends in SIL and STI with different balcony types. It is found that an acoustically treated balcony reduces speech interference. A parapet provides the largest improvement, followed by absorption on the ceiling. The largest reductions in speech interference arise when a combination of balcony acoustic treatments are applied.

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Dr Kathy A. Mills provides a critical synthesis and review of the new book by Matthew W. Hughey entitle: White Bound: Nationalists, Antiractists, and the Shared Meanings of Race, published by Standford University Press in 2012. A sample of Dr Mills' review reads: "The author positions race squarely at the center to challenge the shared assumptions of white supremacist logic on both sides of the debate. The clever thesis blurs the boundaries between “good whites” and “bad whites”, rendering the white reader intellectually stimulated, but existentially unchanged – White Bound – as the author ponders: “Perhaps we have met the enemy, and he [it] is us” (p.193)...The unanswered question that remains is: How do we resist the various “shades” of white supremacy to pursue counter-hegemonic practices?"

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The work described in this technical report is part of an ongoing project to build practical tools for the manipulation, analysis and visualisation of recordings of the natural environment. This report describes the methods we use to remove background noise from spectrograms. It updates techniques previously described in Towsey and Planitz (2011), Technical report: acoustic analysis of the natural environment, downloadable from: http://eprints.qut.edu.au/41131/. It also describes noise removal from wave-forms, a technique not described in the above 2011 technical report.

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This paper takes its root in a trivial observation: management approaches are unable to provide relevant guidelines to cope with uncertainty, and trust of our modern worlds. Thus, managers are looking for reducing uncertainty through information’s supported decision-making, sustained by ex-ante rationalization. They strive to achieve best possible solution, stability, predictability, and control of “future”. Hence, they turn to a plethora of “prescriptive panaceas”, and “management fads” to bring simple solutions through best practices. However, these solutions are ineffective. They address only one part of a system (e.g. an organization) instead of the whole. They miss the interactions and interdependencies with other parts leading to “suboptimization”. Further classical cause-effects investigations and researches are not very helpful to this regard. Where do we go from there? In this conversation, we want to challenge the assumptions supporting the traditional management approaches and shed some lights on the problem of management discourse fad using the concept of maturity and maturity models in the context of temporary organizations as support for reflexion. Global economy is characterized by use and development of standards and compliance to standards as a practice is said to enable better decision-making by managers in uncertainty, control complexity, and higher performance. Amongst the plethora of standards, organizational maturity and maturity models hold a specific place due to general belief in organizational performance as dependent variable of (business) processes continuous improvement, grounded on a kind of evolutionary metaphor. Our intention is neither to offer a new “evidence based management fad” for practitioners, nor to suggest research gap to scholars. Rather, we want to open an assumption-challenging conversation with regards to main stream approaches (neo-classical economics and organization theory), turning “our eyes away from the blinding light of eternal certitude towards the refracted world of turbid finitude” (Long, 2002, p. 44) generating what Bernstein has named “Cartesian Anxiety” (Bernstein, 1983, p. 18), and revisit the conceptualization of maturity and maturity models. We rely on conventions theory and a systemic-discursive perspective. These two lenses have both information & communication and self-producing systems as common threads. Furthermore the narrative approach is well suited to explore complex way of thinking about organizational phenomena as complex systems. This approach is relevant with our object of curiosity, i.e. the concept of maturity and maturity models, as maturity models (as standards) are discourses and systems of regulations. The main contribution of this conversation is that we suggest moving from a neo-classical “theory of the game” aiming at making the complex world simpler in playing the game, to a “theory of the rules of the game”, aiming at influencing and challenging the rules of the game constitutive of maturity models – conventions, governing systems – making compatible individual calculation and social context, and possible the coordination of relationships and cooperation between agents with or potentially divergent interests and values. A second contribution is the reconceptualization of maturity as structural coupling between conventions, rather than as an independent variable leading to organizational performance.

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Solar keratoses (SKs) are induced by exposure to UV radiation and are capable of undergoing transformation to squamous cell carcinoma (SCC).1 The two main factors influencing the occurrence of SK are the sensitivity of the skin to sunlight and the total duration of solar exposure. These factors are responsible for the high incidence of SK in Australia. Although the influence of genetic factors is not defined, there is evidence that the gene encoding the enzyme, glutathione S-transferase, may be implicated in cancer predisposition and therefore SK. Glutathione S-transferase Mu-1 (GSTM1) is an isoenzyme involved in the detoxification of carcinogens. The GSTM1 protein is completely absent in approximately 50% of white persons. This absence is caused by a homozygous gene deletion on chromosome 1p resulting in a null genotype.2 Katoh3 showed that the frequency of the GSTM1 null genotype was significantly higher in 85 patients with urothelial cancer (61.2%; p < 0.05), suggesting that the null genotype may increase cancer susceptibility. This finding was supported by Lafuente et al.4 who found evidence that persons who lack the GSTM1 gene have approximately twice the chance of experiencing malignant melanoma. Further research in the United Kingdom found that patients with two or more skin tumors of different types, basal cell carcinoma (BCC) and SCC, had a significantly higher frequency of GSTM1 null genotypes than controls (71%; p = 0.033). However the GSTM1 genotype in patients with only SCC was not excessive in this population.5 Persons residing in northern Australia have the highest incidence of nonmelanoma skin cancer (SCC and BCC) in the world6 and receive far greater solar exposure than persons residing in the United Kingdom. It is possible that the GSTM1 null genotype may affect susceptibility to SK, which may act as SCC precursors, in Australians exposed to these high levels of solar radiation.

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This thesis studied the source of instability in optical phase modulators used in high accuracy laser measurement systems. The nonlinear origin of the amplitude noise helped further reducing this instability in applications that rely on phase modulators to function. This outcome will have positive impacts on the development of new methods in the amplitude noise suppression.

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Residential balcony design influences speech interference levels caused by road traffic noise and a simplified design methodology is needed for optimising balcony acoustic treatments. This research comprehensively assesses speech interference levels and benefits of nine different balcony designs situated in urban street canyons through the use of a combined direct, specular reflection and diffuse reflection path theoretical model. This thesis outlines the theory, analysis and results that lead up to the presentation of a practical design guide which can be used to predict the acoustic effects of balcony geometry and acoustic treatments in streets with variable geometry and acoustic characteristics.

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Our results demonstrate that photorefractive residual amplitude modulation (RAM) noise in electro-optic modulators (EOMs) can be reduced by modifying the incident beam intensity distribution. Here we report an order of magnitude reduction in RAM when beams with uniform intensity (flat-top) profiles, generated with an LCOS-SLM, are used instead of the usual fundamental Gaussian mode (TEM00). RAM arises from the photorefractive amplified scatter noise off the defects and impurities within the crystal. A reduction in RAM is observed with increasing intensity uniformity (flatness), which is attributed to a reduction in space charge field on the beam axis. The level of RAM reduction that can be achieved is physically limited by clipping at EOM apertures, with the observed results agreeing well with a simple model. These results are particularly important in applications where the reduction of residual amplitude modulation to 10^-6 is essential.

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This study explored the way white teachers speak about Indigenous students and communities. The accounts of teachers working in eight schools across Australia were analysed using Foucauldian discourse analysis. The research found that deficit and colour-blind discourses dominate the ways that white teachers "know" Indigenous students and families. The data indicates that colour-blind and compensatory pedagogies are employed heavily by teachers working with Indigenous students, and highlights the complexities and tensions that exist in schools. Although there is evidence of some disruption to dominant discourses, teachers' discursive resources are limited in terms of imagining and enacting more equitable pedagogies.