<div>Fluid power is widely used in a variety of applications such as construction machines, aerospace, automotive, agricultural machinery, manufacturing, etc. Although this technology has many obvious advantages such as compactness, robustness, high power density, and so forth, there is much room for improvement, of which one of the most important and challenging problems is the noise.</div><div><br></div><div>Different institutes have been researching fluid power noise for decades. However, much of the experimental investigation was based on simple measurement and analysis techniques, which left the designers/researchers no method of understanding the complicated phenomena. A microphone array is a powerful tool that unfortunately has not been introduced to the fluid power noise research. By capturing the magnitude and phase information in space, a microphone array enables the noise source identification, separation, localization and so forth.</div><div><br></div><div>This thesis focuses on implementing the microphone array processing techniques on a synthetic microphone array for fluid power noise diagnostics. Differing from traditional scan-based approaches, the synthetic array is created by synchronizing the non-synchronous measurements to achieve the equivalent effect of a multi-microphone snapshot. The final results will show the power of microphone arrays and provide an economical solution to achieve approximate results when a real microphone array is not available.</div>

The theoretical part of the diploma thesis focuses on sources of noise in stables for dairy farming. This issue also relates to welfare of cattle and the last subject to be dealt with can be called working environment in livestock production in terms of noise load. The practical part is focused on the description of technological equipment of the stables with a plan of the measured objects. The measurement of noise levels during technological operations with cattle was carried out at selected dairy cows at the workplaces of the Agricultural Cooperative of Velká Losenice. Then the work deals with measurement of the operator's noise load during the partial operations necessary to ensure the process of dairy cows breeding. At the end of the diploma thesis the processing of individual measurement results in individual operations in measured objects is presented and evaluation of the noise load.

A maior parte do ruído de aeronaves é advinda dos motores. Como houve grande avanço no controle do ruído tonal, atualmente grande parte do esforço se dá para redução do ruído de banda larga, que é menos compreendido. O ruído de banda larga é gerado pela interação entre um escoamento turbulento e uma superfície, como por exemplo, a turbulência ingerida interagindo com o rotor, o escoamento na ponta das pás, entre outros. Apesar das diversas fontes citadas, sabe-se que a principal fonte de ruído de banda larga em tal tipo de motor é a interação da esteira turbulenta do rotor com as aletas da estatora. Assim, o presente estudo manterá seu enfoque apenas em tal causa. O objetivo deste então é o desenvolvimento de um modelo capaz de previsão do ruído de banda larga pela interação da esteira turbulenta causada pelo rotor, interagindo com as aletas da estatora, bem como o entendimento da propagação do ruído em duto. A primeira abordagem em relação a tal tipo de ruído é através da previsão do ruído gerado. Para previsão de ruído podem ser utilizados métodos analíticos, numéricos, ou empíricos, cada qual com suas vantagens e penalizações. Para tal, foi utilizado um método semi-analítico, em tais métodos utiliza-se simulação numérica para previsão da característica da turbulência e uma teoria analítica para a geração e propagação do ruído no duto. A principal motivação para o método semi-analítico é sua vantagem em relação aos métodos numéricos que demandam custo computacional extremamente alto e vantagem em relação a métodos analíticos que necessitariam uma demasiada simplificação geométrica. Dessa maneira, utilizou-se a geometria do ANCF, uma plataforma de ensaios desenvolvida pela NASA, onde havia geometria e resultados divulgados, tornando possível a verificação dos resultados obtidos. Os resultados mostram que as tendências capturadas são condizentes com o esperado, e então com um tempo relativamente baixo, de maneira prática, é possível a previsão do ruído de interação e sua propagação em dutos nos motores turbofans. / The major noise source in aircraft is the engine. Since tonal noise control is well developed, the current effort concentrates on broadband noise reduction, which is less understood. The broadband noise is generated when a turbulent flow interacts with a surface as, for example, rotor blade tip flow, boundary layer and the rotor interaction. Although there are different sources of broadband noise it is known that the major broadband source in turbofan engine is the rotor turbulent wake interacting with the stator vanes. This study is focused in that source of noise and the goal is to develop a model capable of predicting the rotor/stator interaction noise as well as in duct noise propagation. Noise prediction can be carried out by analytical, numerical or empirical methods, each one with advantages and disadvantages. In the present work the semi-analytical method was used. Turbulence characteristics were estimated by a numerical method and the noise generation and duct propagation was estimated by an analytical method. The biggest advantage comparing with the numerical methods is that this method is less time consuming. A purely analytical method would require excessive geometric simplification. The ANCF, a rig developed by NASA was used as basis for the simulations, since its geometry and noise data are available. The results show that the correct trends are consistently captured. So it is concluded that it is possible to predict the broadband noise and its propagation in turbofans engines with a practical and low cost method.

Levels of underwater noise in the open ocean have been increasing since at least the 1960s due to growth in global shipping traffic and the speed and propulsion power of vessels. This rise in noise levels reduces the range over which vocal marine species can communicate, and can induce physiological stress and behavioural responses, which may ultimately have population-level consequences. Although long-term noise trends have been studied at some open-ocean sites, in shallower coastal regions the high spatiotemporal variability of noise levels presents a substantial methodological challenge, and trends in these areas are poorly understood. This thesis addresses this challenge by introducing new techniques which combine multiple data sources for ship noise assessment in coastal waters. These data include Automatic Identification System (AIS) ship-tracking data, shore-based time-lapse footage, meteorological data, and tidal data. Two studies are presented: in the first, AIS data and acoustic recordings from Falmouth Bay in the western English Channel are combined using an adaptive threshold, which separates ship passages from background noise in the acoustic data. These passages are then cross-referenced with AIS vessel tracks, and the noise exposure associated with shipping activity is then determined. The second study, at a site in the Moray Firth, Scotland, expanded the method to include shore-based time-lapse footage, which enables visual corroboration of vessel identifications and the production of videos integrating the various data sources. Two further studies examine and enhance basic analysis techniques for ambient noise monitoring. The first study examines averaging metrics and their applicability to the assessment of noise from shipping. Long-term data from the VENUS observatory are empirically assessed for different averaging times and in the presence of outliers. It is concluded that the mean sound pressure level averaged in linear space is most appropriate, in terms of both standardization and relevance to impacts on marine fauna. In the second study, a new technique for the statistical analysis of long-term passive acoustic datasets, termed spectral probability density (SPD), is introduced. It is shown that the SPD can reveal characteristics such as multimodality, outlier influence, and persistent self-noise, which are not apparent using conventional techniques. This helps to interpret long-term datasets, and can indicate whether an instrument’s dynamic range is appropriate to field conditions. Taken together, the contributions presented in this thesis help to establish a stronger methodological basis for the assessment of shipping noise. These methods can help to inform emerging policy initiatives, efforts to standardise underwater noise measurements, and investigation into the effects of shipping noise on marine life.

The use of procedural content generation is becoming more and more popular in the video game industry. With games such as Minecraft or No Man’s Sky we have seen the potential of PCG in video game creation but also its challenges. In fact, while the processing power and memory capabilities of our machines are unceasingly growing, human capability for content creation doesn’t seem to be able to follow the same pace. Game developers had then to come up with several techniques and methods that will help them generate lots of content for their games while still keeping a certain level of control on the output. Urbis Terram is a procedural city generation tool for Unity3D that allows the creation of complete cities to be used in video games or simulations made with this engine. The goal of this thesis is to tackle the technical challenge of designing and implementing a PCG tool that will help game developers to quickly generate terrains, road networks and allotment spaces for buildings and other urban areas. The goal is to have a unique complete city generation tool that can enable quick game design iterations and can be used to create complex virtual worlds.

"Speech enhancement in an automobile is a challenging problem because interference can come from engine noise, fans, music, wind, road noise, reverberation, echo, and passengers engaging in other conversations. Hands-free microphones make the situation worse because the strength of the desired speech signal reduces with increased distance between the microphone and talker. Automobile safety is improved when the driver can use a hands-free interface to phones and other devices instead of taking his eyes off the road. The demand for high quality hands-free communication in the automobile requires the introduction of more powerful algorithms. This thesis shows that a unique combination of five algorithms can achieve superior speech enhancement for a hands-free system when compared to beamforming or spectral subtraction alone. Several different designs were analyzed and tested before converging on the configuration that achieved the best results. Beamforming, voice activity detection, spectral subtraction, perceptual nonlinear weighting, and talker isolation via pitch tracking all work together in a complementary iterative manner to create a speech enhancement system capable of significantly enhancing real world speech signals. The following conclusions are supported by the simulation results using data recorded in a car and are in strong agreement with theory. Adaptive beamforming, like the Generalized Side-lobe Canceller (GSC), can be effectively used if the filters only adapt during silent data frames because too much of the desired speech is cancelled otherwise. Spectral subtraction removes stationary noise while perceptual weighting prevents the introduction of offensive audible noise artifacts. Talker isolation via pitch tracking can perform better when used after beamforming and spectral subtraction because of the higher accuracy obtained after initial noise removal. Iterating the algorithm once increases the accuracy of the Voice Activity Detection (VAD), which improves the overall performance of the algorithm. Placing the microphone(s) on the ceiling above the head and slightly forward of the desired talker appears to be the best location in an automobile based on the experiments performed in this thesis. Objective speech quality measures show that the algorithm removes a majority of the stationary noise in a hands-free environment of an automobile with relatively minimal speech distortion."

Made available in DSpace on 2016-04-27T18:12:01Z (GMT). No. of bitstreams: 1 Aidilma Silva Ferreira.pdf: 1574476 bytes, checksum: 6b240b6332f8c9109f21e4896d438d70 (MD5) Previous issue date: 2013-07-31 / Noise is an important public health problem. Hospitals, that should provide adequate conditions for acoustic comfort to its patients and employees, are not considered quiet environments, which can bring harm to their health. Objective. To verify the newborn assistance health professionals exposure to occupational noise and to investigate their auditory and non-auditory complaints. Method. The sample consisted of 34 nursing technicians and 32 nursing assistants, all female. The age ranged from 24 to 56 years, with a mean of 37.4. The study of the noise perception was performed using a questionnaire. Sound levels were measured by noise dosimetries on employees during their working hours in day and night shifts. Two Wed007 type 2 dosimeters of the 01dB trademark were used. Statistical analysis was performed using chi-square test to assess the relations between the variables. Results. Most professionals considered the environment to be noisy (98.4%) and believed they, somehow, contributed to ambient noise. The main noise sources reported were equipment and monitoring alarms and people talking. The discomfort, stress, fatigue and irritability were complaints that affected the professionals in a greater degree because of the sense of ambient noise. Statistically significant associations (p <0.05) with stress, fatigue and discomfort in individuals who had the perception that the environment was noisy were found. Professionals who felt more stressed because of the environmental noise perception believed that the noise interfered with their work efficiency (p = 0.002) and thinking (p = 0.010), and reported to be very or extremely annoyed by noise (p = 0.000), bad mood (p = 0.000) and irritability (p = 0.000), being harder to understand others speech (p = 0.000). The most common effects were headache and sensitivity to loud noise. LAeq levels ranged from 70.3 dB (A) to 82.5 dB (A). The minimum levels were in the range of 42.3 dB (A) and 55 dB (A). The maximum levels ranged from 81.3 dB (A) to 94.2 dB (A). Conclusions. Sound levels were higher than those recommended by the acoustic comfort standards. Important statistical associations between the noisy environment and the professionals health complaints were found. The noise can affect oral communication aspects and workers task performance / O ruído representa um importante problema de saúde pública. Os hospitais, que deveriam fornecer adequadas condições de conforto acústico aos seus pacientes e funcionários, não são considerados ambientes silenciosos, o que pode trazer prejuízo à saúde destes. Objetivo. Verificar a exposição a ruído ocupacional da equipe de profissionais de saúde que atua em setores de assistência a recém-nascido e investigar suas queixas auditivas e não auditivas. Método. A amostra foi composta por 34 técnicas de enfermagem e 32 auxiliares de enfermagem, todas do sexo feminino. A idade variou de 24 a 56 anos, sendo a média igual a 37,4. O estudo da percepção do ruído foi realizado por meio da aplicação de um questionário. Os níveis sonoros foram medidos por meio de dosimetrias de ruído nos funcionários durante a jornada de trabalho, nos turnos diurno e noturno. Foram utilizados dois dosímetros do tipo 2, modelo Wed007, marca 01dB. A análise estatística foi realizada por meio de teste qui-quadrado, para verificar as associações entre as variáveis de estudo. Resultados. A maioria dos profissionais considerou o ambiente ruidoso (98,4%) e acredita que contribui com o barulho. As principais fontes de ruído relatadas foram os equipamentos e alarmes de monitoramento e as pessoas conversando. O incômodo, o estresse, o cansaço e a irritabilidade foram as queixas que afetaram os profissionais em maior grau devido à sensação do ruído ambiente, sendo encontradas associações estatisticamente significantes (p<0,05) com o estresse, o incômodo e o cansaço em indivíduos que tinham a percepção de que o ambiente é barulhento. Os profissionais que se sentiam mais estressados pela percepção do ruído do ambiente acreditavam que o ruído atrapalhava sua eficiência no trabalho (p=0,002) e o raciocínio (p=0,010), bem como sentiam que o ruído incomodava bastante ou extremamente (p=0,000), causava mau-humor (p=0,000) e irritabilidade (p=0,000), atrapalhando entender a fala dos outros (p=0,000). Os sintomas mais relatados foram cefaleia e incômodo a sons fortes. Os valores de LAeq variaram de 70,3 dB(A) a 82,5 dB(A). Os níveis mínimos se encontravam na faixa entre 42,3 dB(A) e 55 dB(A). Os níveis máximos encontrados variaram de 81,3 dB(A) a 94,2dB(A). Conclusões. Os níveis sonoros encontrados estavam acima dos recomendados pelas normas de conforto acústico. Foram encontradas importantes associações estatísticas entre o ambiente barulhento e queixas de saúde dos profissionais. O ruído pode prejudicar aspectos relacionados à comunicação oral e afetar na execução das atividades destes profissionais

Made available in DSpace on 2016-04-27T18:12:11Z (GMT). No. of bitstreams: 1 Marjorie Juliana Silva Grudtner.pdf: 1211380 bytes, checksum: 9287944948f7dffd336cb8b8af047767 (MD5) Previous issue date: 2015-11-17 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Continuous noise exposure can cause hearing effects and non-hearing. The annoyance is the one of the most important effect of noise exposure. The annoyance of exposure of noise can cause several negative responses such as anxiety, restlessness, disappointment, depression, distraction, exhaustion, dissatisfaction, anger. Purpose: To evaluate the annoyance and the others complaints by noise among taxi drivers in the city of São Paulo-SP. Method: The sample size was 153 taxi drivers. Auditory and non auditory noise effects was conducted through a questionnaire adapted, based on Ferreira (2013). Statistical analysis was performed using the chi-square test to assess the association between the study variables and four outcomes (annoyance, stress, communication disorders and hearing loss). Cronbach s Alpha Test was used to analyze the questionnaire reliability. Results: Most taxi drivers (73.86%) makes no mention of quiet or tranquility as their place of work and 83% consider the noise of moderate to intense. 58.48% think that adds to the existing noise. The main sources of noise outside the vehicle taxi drivers were cited by the vehicle traffic, construction and trade. The adverse effects of noise, the most observed were: stress, discomfort, difficulty communicating and understanding what others say, moodiness, irritability, fatigue and tinnitus. 60% of taxi drivers think the noise can harm them in some way, and the stress (11.11%) and hearing loss (9.15%) were the most cited. To decrease the 43.14% noise suggested education and awareness of individuals. Regarding the hearing, only 32.68% think that hears the same way he heard before. Significant associations were found with the four outcomes with the following variables: the lack of attention, dizziness, moodiness, annoyance, pressure rise, tinnitus, fatigue, lack of appetite, interference with work efficiency and implementation tasks. As for the first three outcomes (annoyance, stress and communication difficulties) the variable with significance was the hearing of the change in self-perception. Variables: irritation, work efficiency, uncomfortable with loud sounds, inattention, understand what others say appeared related only to stress outcomes and difficulty communicating with others. Conclusion: annoyance, stress, difficulty communicating and self-perception of hearing loss were statistically associated with urban noise and several adverse health effects resulting from this exposure. The internal consistency (reliability) of the questionnaire used in the survey was excellent / A exposição ao ruído pode causar alterações tanto auditivas como não auditivas. Dentre os efeitos mais preocupantes desta exposição na saúde está o incômodo. O incômodo causado pelo ruído pode levar a diversas respostas negativas como a ansiedade, agitação, decepção, depressão, distração, exaustão, insatisfação, raiva. Objetivo: Verificar o incômodo e outras queixas de saúde relacionados ao ruído urbano em taxistas do município de São Paulo. Método: A amostra foi constituída por 153 taxistas. A investigação do incômodo provocado pelo ruído e outros efeitos, foi realizado por meio do questionário adaptado, baseado em Ferreira (2013). A análise estatística foi realizada pra verificar as associações entre as variáveis do estudo e os quatro desfechos (incômodo, estresse, dificuldade de comunicação e autopercepção da perda auditiva). Para a análise de confiabilidade do questionário foi utilizado do teste de Alpha de Cronbach. Resultados: A maioria dos taxistas (73,86%) não faz nenhuma menção à quietude ou tranqüilidade quanto ao seu local de trabalho e 83% considera o barulho de moderado a intenso. 58,48%acha que contribui para o ruído existente. As principais fontes de ruído externas ao veículo citadas pelos taxistas foram o tráfego de veículos, construção civil e o comércio. Quanto aos efeitos adversos do ruído, os mais observados foram: estresse, incômodo, dificuldade para se comunicar e entender o que os outros falam, mau humor, irritação, cansaço e o zumbido. 60% dos taxistas acham que o ruído pode prejudicá-los de alguma forma, sendo o estresse (11,11%) e a perda auditiva (9,15%) os mais citados. Para diminuir o ruído 43,14% sugeriram a educação e a conscientização dos indivíduos. Em relação à audição, somente 32,68% acha que ouve da mesma forma que ouvia antes. Foram encontradas associações significativas com os quatro desfechos com as seguintes variáveis: a falta de atenção, tontura, mau humor, incômodo, aumento de pressão, zumbido, cansaço, falta de apetite, interferência na eficiência do trabalho e na execução de tarefas. Enquanto para os três primeiros desfechos (incômodo, estresse e a dificuldade de comunicação) a variável com significância foi à autopercepção de alteração da audição. As variáveis: irritação, eficiência no trabalho, incômodo com sons fortes, desatenção, entender o que os outros falam apareceram associadas somente aos desfechos de estresse e dificuldade de comunicação com os outros. Conclusão: Incômodo, o estresse, a dificuldade de se comunicar e a autopercepção da perda auditiva foram estatisticamente associados com o ruído urbano e com vários efeitos adversos na saúde, decorrentes desta exposição. A consistência interna (confiabilidade) do questionário utilizado na pesquisa foi excelente

Thesis. 1976. Sc.D.--Massachusetts Institute of Technology. Dept. of Mechanical Engineering. / Microfiche copy available in Archives and Engineering. / Vita. / Includes bibliographical references. / by Paul R. Donavan. / Sc.D.

Thesis. 1978. M.S. cn--Massachusetts Institute of Technology. Dept. of Mechanical Engineering. / Includes bibliographical references. / by Ilene J. Busch-Vishniac. / M.S.cn