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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Avaliação do uso de barreira acústica para escolas municipais em Porto Alegre

Soares, Fabiano Silva 06 July 2018 (has links)
Submitted by JOSIANE SANTOS DE OLIVEIRA (josianeso) on 2018-10-04T15:52:02Z No. of bitstreams: 1 Fabiano Silva Soares_.pdf: 6002873 bytes, checksum: ea33db7736d31eb82667a95bd42f7013 (MD5) / Made available in DSpace on 2018-10-04T15:52:02Z (GMT). No. of bitstreams: 1 Fabiano Silva Soares_.pdf: 6002873 bytes, checksum: ea33db7736d31eb82667a95bd42f7013 (MD5) Previous issue date: 2018-07-06 / Nenhuma / O crescimento desordenado das cidades tem aumentado significativamente a poluição sonora, ao mesmo tempo que ocasionam desgaste nas relações entre vizinhos, prejudicando o bem-estar da comunidade. Uma das alternativas utilizadas para reduzir estes efeitos são as barreiras acústicas, visto que se configuram numa das soluções mais eficazes para a redução da propagação do som em área livre. Neste panorama, a escola sempre foi tratada como receptora sensível, sendo raramente considerada emissora do ruído, em virtude deste fato é que a dissertação se desenvolve. Desta forma, neste trabalho é proposta a utilização de barreiras acústicas como forma de solucionar a livre propagação do som emitido durante atividades de recreação em duas unidades educacionais do município de Porto Alegre. O principal problema consiste em se reduzir os níveis de pressão sonora incidente nas edificações vizinhas, afim de garantir o atendimento aos níveis estabelecidos pelas normas ABNT NBR 10151 e 10152. Por ser fundamentado em situações reais, o estudo de caso envolveu levantamentos de campo dos espaços físicos das escolas e das residências vizinhas, ensaios em laboratório para determinação do coeficiente de absorção sonora, ensaios em campo para a determinação dos níveis de pressão sonora emitidos pelas crianças nas escolas. As medições em campo indicaram que os níveis sonoros internos nas residências vizinhas e externos nos playgrounds estão acima dos indicados pelas normas. Para a sequência do trabalho, foi desenvolvido um protótipo de barreira sonora, utilizando conceitos de reflexão sonora e absorção, tal como um ressonador de Helmholtz e após, ensaiado em laboratório. Com os dados obtidos nos ensaios laboratoriais da amostra, se obteve um coeficiente de absorção sonora ponderado (αw) de 0,7. O software CadnaA® foi a ferramenta utilizada para a realização de simulação dos projetos das barreiras acústicas em ambas escolas, sendo demonstrada uma redução de 15 dB para a escola Jardim Camaquã e 5 dB para a escola Unidos da Paineira, sendo que a utilização do acabamento de topo com inclinação apresentou redução significativa apenas na escola Jardim Camaquã. A proposta da inserção das barreiras sonoras se mostrou relevante, mas ainda assim, não atingiu os valores determinados pelas normas. / The disorderly growth of cities has contributed to a significant increase of noise pollution, at the same time as it causes frictions between neighbors, jeopardizing the well-being of communities. One of the alternatives used to reduce these effects is the adoption of acoustic barriers, since it is one of the most effective solutions to reduce the propagation of sound in open space. In the scenario, the school has always been seen as a sensitive receptor, and hardly ever considered a sound emitter, and this is the research subject of the present dissertation. Therefore, this work proposes to discuss the use of acoustic barriers as a way to solve the free propagation of emitted sound during recreation activities in two educational facilities in the city of Porto Alegre. The main problem consists in reducing the levels of sound pressure that reach neighboring buildings, as a way to guarantee the observance of levels established by the Associação Brasileira de Normas Técnicas (ABNT – Brazilian Association of Technical Norms) in the norms NBR 10151 and 10152. As it was grounded in real situations, the case study involved field surveys to assess school and neighboring building physical spaces, laboratory tests to determine the sound absorption coefficient, and field tests to determine the levels of sound pressure emitted by children at the schools. The field tests showed that noise levels inside the neighboring buildings and outside on the playgrounds were above the ones established in the norms. For the continuity of the study, a sound barrier prototype was built, using concepts of noise reflection and absorption, as the Helmholtz resonator, and then tested in laboratory. According to the results obtained with the sample, a weighted sound absorption coefficient (αw) of 0.7 was obtained. The CadnaA® software was the tool used to conduct simulations of sound barrier projects in both schools. A reduction of 15 dB was demonstrated at Jardim Camaquã School, whilst a 5 dB reduction was demonstrated at Unidos da Paineira School, being that the use of inclined top finish only represented significant reduction at Jardim Camaquã School. The use of sound barriers was proved relevant, but even so the levels established by norm were not reached.
12

Research and Digital Modelling of Environmental Noise and its Reduction by applying Light Structures / Aplinkos triukšmo ir jo mažinimo, taikant lengvas konstrukcijas, tyrimai bei skaitinis modeliavimas

Grubliauskas, Raimondas 13 July 2009 (has links)
General characteristic of the dissertation Problem of the work. With a rapid development of industrialisation and urbanisation, the environmental pollution has greatly increased. Upon automating the manufacturing industry and agriculture, with traffic flows in towns and residential areas increasing and household equipment becoming more modern, the number of acoustic discomfort zones is rapidly growing. People are exposed to noise not only at workplaces abut also on the streets and at home. As maintained by doctors, noise reduces immunity of the organism and, as a source of chronic stress, has an adverse effect on the central nervous system and causes various health disorders. Even a relatively low noise of 60–70 dB causes a headache, dizziness, squeak in the ears, insomnia, and worsens memory, attention and orientation. A noisy environment reduces working efficiency, reaction speed, movement coordination and increases nervous strain and a risk of traumas. The noise dispersed by stationary sources may be reduced by replacing components with less sounding ones, applying rubber, plastic or other materials on the surface of installations. If it is impossible to reduce noise in the place of its generation, hoods are fitted out, premises are insulated and noise suppressing systems are used (noise reducing barriers, volumetric noise absorbers, wall insulation with noise-proof materials). The dispersion of traffic-generated noise is reduced by noise suppression walls, green... [to full text] / Tiriamoji problema. Šiandieniniame gyvenime, mechanizavus pramonės ir žemės ūkio gamybą, didėjant transporto srautams miestuose ir gyvenvietėse, modernėjant buitinei technikai, sparčiai plečiasi padidinto triukšmo zonos. Medikai teigia, kad triukšmas mažina organizmo imuninį atsparumą ir įspėja, kad triukšmas, kaip lėtinis streso šaltinis, veikia centrinę nervų sistemą ir kelia įvairių sveikatos sutrikimų. Net palyginus nestiprus 60 – 70 dB triukšmas kelia galvos skausmus, nemigą, pablogėja atmintis, dėmesys, darbingumas. Stacionarių šaltinių skleidžiamas triukšmas sumažinamas keičiant detales keičiant, padengiant įrenginių paviršių guma, plastmase ir kt. Jeigu neįmanoma sumažinti triukšmo ten, kur jis kyla, įrengiami gaubtai, izoliuojamos patalpos, bei taikomos garsą slopinančios sistemos (triukšmą mažinantys barjerai, tūriniai garso sugėrikliai, sienos dengiamos garsą izoliuojančia medžiaga). Transporto keliamo triukšmą sklaidą mažina triukšmo slopinimo sienelės, želdiniai, pastatai. Taip pat veiksmingi būdai yra transporto greičio apribojimas, kelių dangos paviršiaus keitimas, eismo ribojimas ir reguliavimas. Inžineriniai sprendimai būna pigesni, jei įvertinami architektūrinio planavimo stadijoje. Nagrinėjant triukšmo mažinimo priemonių bei metodų įgyvendinimo galimybę, ypač svarbus skaitinis triukšmo sklaidos modeliavimas. Darbo aktualumas. Įvairūs technologiniai procesai kelia triukšmą. Leistini triukšmo lygiai viršijami ne tik darbo vietose ar įmonės teritorijose... [toliau žr. visą tekstą]
13

Aplinkos triukšmo ir jo mažinimo, taikant lengvas konstrukcijas, tyrimai bei skaitinis modeliavimas / Research and Digital Modelling of Environmental Noise and its Reduction by Applying Light Structures

Grubliauskas, Raimondas 13 July 2009 (has links)
Disertacijoje nagrinėjamas triukšmo šaltinių keliamo triukšmo sklidimas į aplinką bei ieškoma mažinimo priemonių jam slopinti. Disertacijos tikslas – įver-tinti stacionarių ir mobilių šaltinių keliamo triukšmo sklaidą aplinkoje ir numatyti efektyvias priemones jai mažinti, naudojant triukšmo slopinimo kamerą, o prie-monių efektyvumą įvertinti modeliuojant. Šiame darbe sprendžiami keli pagrindiniai uždaviniai: sukurti ir įrengti triukšmo slopinimo kamerą; nustatyti triukšmo sklaidą, esant skirtingiems mobi-liems ir stacionariems triukšmo šaltiniams; numatyti bei modeliavimo būdu įver-tinti priemones triukšmui slopinti. Disertaciją sudaro įvadas, penki skyriai, rezultatų apibendrinimas, naudotos literatūros ir autoriaus publikacijų disertacijos tema sąrašai. Įvadiniame skyriuje aptariama tiriamoji problema, darbo aktualumas, apra-šomas tyrimų objektas, formuluojamas darbo tikslas bei uždaviniai, aprašoma tyrimų metodika, darbo mokslinis naujumas, darbo rezultatų praktinė reikšmė, ginamieji teiginiai. Įvado pabaigoje pristatomos disertacijos tema autoriaus pa-skelbtos publikacijos ir pranešimai konferencijose bei disertacijos struktūra. Pirmasis skyrius skirtas literatūros apžvalgai. Jame išnagrinėti skirtingi triukšmo parametrai, jo šaltiniai, triukšmo mažinimo būdai, poveikis aplinkai, triukšmo sklaidos modeliavimo programos bei medžiagų akustinių savybių tyri-mai. Skyriaus pabaigoje formuluojamos išvados. Antrajame skyriuje pateiktos eksperimentinių tyrimų, skirtingų šaltinių... [toliau žr. visą tekstą] / The dissertation analyses the problem of environment noise pollution and mitigation. The dissertation is aimed to evaluate the dispersion of noise from sta-tionary and mobile sources, provide for effective techniques and measures to re-duce it by using a noise suppression chamber for research into acoustic properties and to estimate the efficiency of the noise reduction measures through modelling. The work deals with main tasks: to design and fit out a noise suppression chamber and use it for research into the noise absorption and insulation proper-ties of different materials; to determine the levels and dispersion of noise from different mobile and stationary sources of noise; to determine the longitudinal sound wave attenuation coefficient for individual building materials and for buil-ding structures - the airborne sound attenuation index; to estimate the efficiency of the measures reducing noise from diferent sources with software “CadnaA”. The scientific work consist of the general characteristic of the dissertation, 5 chapters, conclusions and recommendations, list of literature, list of publications. The introduction discusses the problem addressed, topicality of the work, describes the object of research, and formulates the aim and tasks of the work, scientific novelty of the work, practical value of the research results and defen-ded propositions. It presents the author’s publications and conference reports on the topic of the dissertation and the structure of the... [to full text]
14

Caracterização acústica de dois sistemas modulares de telhados verdes brasileiros / Acoustic characterization of two brazillian systems of modular green roofs

Piovesan, Tenile Rieger 20 December 2013 (has links)
This study aimed to experimentally evaluate the properties as sound absorbers of two modular green roof systems commonly used in Brazil: the Alveolar simple and the modular Hexa. This study emerged from the unification of two aggravating problems, being the environment degradation and the environmental noise, given the records that vegetated roofs generally have several environmental benefits, including acoustic. The two systems were evaluated with the same substratum, but with different features and using distinct plants and assembly modes, that is, grass on the Alveolar system and plants of the sedum genus on the Hexa modular system. Measuring experiments of sound absortion have been made for each of the systems, consisting of two measurings with different substratum thickness and one measuring of the systems with sedum plants. The chosen experimental procedure was the method of reverberation chamber in a diffuse sound field. It was found that substrata of all the combinations of investigated samples have interesting absorption properties, due their porosity. The maximum sound absorption coefficient α of the Alveolar system with 2.5cm thick substratum was 1.0 at 1kHz, and the lower frequency coefficient are close to 0.20. The Alveolar system with 4 cm of substratum and the Hexa modular system with sedum plants were those which had, in general, higher values for α in all frequency bands, as well as showing the highest NRC values, in other words: values of 0.80 and 0.81 respectively. The maximum α in the Alveolar system with a layer of 4 cm thick substratum reached the value of 0.89 at frequencies of 1 kHz, 2 kHz and 2.5 kHz, and at the low frequencies from 100 Hz to 200 Hz the sample reached α values between 0.25 and 0.32; whereas the Hexa modular system with a 6cm substratum plus sedum the α values were 0.94 at a frequency of 800Hz, and between 0.16 and 0.26 at low frequencies. The 4cm thick Alveolar system with grass was the system which had higher α values in the frequencies of 100Hz and 200Hz, between 0.31 and 0.38, therefore being most efficient for traffic noise absorption. In general, the absorption coefficients of all samples doubled the value at the range of 250Hz, in comparison to the 200Hz frequency. The obtained results show a high absorption coefficient for such systems, which indicates that using green roofs can be na effective alternative of urban noise control. / Este estudo teve como objetivo principal avaliar experimentalmente as propriedades como absorvedores sonoros de dois sistemas modulares de telhados verdes comumente utilizados no Brasil: alveolar simples e hexa. Este eclodiu da unificação de dois problemas agravantes, sendo a degradação do meio ambiente e ruído ambiental, partindo-se dos registros que telhados vegetados de forma geral possuem vários benefícios ambientais, inclusive acústicos. Foram analisados os dois sistemas com a mesma composição de substrato, porém com particularidades no esquema de montagem e plantas diferenciadas, isto é, grama no sistema alveolar e planta do tipo sedum no sistema hexa. Foram realizados experimentos de medição de absorção sonora de cada um dos sistemas, sendo duas medições considerando espessuras diferenciadas de substrato e uma medição do conjunto com planta. O procedimento experimental foi o método da câmara reverberante em campo difuso. Verificou-se que os substratos das amostras de todas as combinações investigadas possuem interessantes propriedades de absorção, por serem altamente porosos. O coeficiente de absorção sonoro (α) máximo do sistema alveolar com 2,5cm de substrato foi de 1,0 em 1 kHz, e nas baixas frequências tem coeficientes próximos de 0,20. Já o sistema alveolar com 4 cm de substrato e o sistema hexa com sedum foram os que apresentaram, no geral, maiores valores no α em todas as faixas de frequência, além de apresentarem em termos de NRC os maiores valores, ou seja: 0,80 e 0,81 respectivamente. O α máximo no sistema alveolar com 4 cm de espessura do substrato atingiu 0,89 nas frequências de 1kHz, 2kHz e 2,5 kHz, e nas baixas frequências valores de α entre 0,25 à 0,32 nas frequências de 100 à 200 Hz; já no sistema hexa com espessura do substrato de 6cm com sedum o α máximo foi de 0,94 na frequência de 800Hz, e nas baixas frequências entre 0,16 a 0,26. O sistema alveolar com espessura de 4 cm com grama foi o que obteve maiores α nas baixas frequências de100 a 200 Hz com valores de 0,31 a 0,38, sendo assim mais eficaz para absorção de ruído de tráfego. No geral, os coeficientes de absorção de todas as amostras dobraram o valor na faixa de 250 Hz em relação a 200 Hz. Os resultados obtidos indicam um alto coeficiente de absorção para tais equipamentos, o que sugere que a utilização de telhados verdes pode ser uma ótima alternativa de controle de ruído urbano.
15

Repertório vocal e variações no canto de Basileuterus spp. (Passeriformes, Parulidae) em fragmentos de mata (Uberlândia, MG) / Vocal repertoire and song s variation in Basileuterus spp. Wood Warbler (Passeriformes, Parulidae) in forest fragments (Uberlândia, MG)

Carvalho, Liliane Souza Dantas de 09 March 2010 (has links)
Fundação de Amparo a Pesquisa do Estado de Minas Gerais / Bird s vocalization is directly related with vital behaviors. Some species are very sensitive to changes in sound characteristics of vocalizations. The Oscine Passerines, because they have more complex syrinx and vocal learning capacity, are one of the group with higher possibility of present variation in their voice. This study selected three sympatric and partially syntopic of Oscine Passerines, Parulidae: Flavescent Warbler (Basileuterus flaveolus), White-bellied Warler (B. hypoleucus) and White-striped Warbler (B. leucophrys) aiming to characterize the vocal repertoire of Basileuterus spp., and whether these species alter the vocal parameters of their songs with the factors seasonality, distribution of fragments and the environmental noise. The study was conducted in Uberlândia, MG, in fragments of semideciduous forest in the Cerrado. In characterizing the vocal repertoire and to verify the effect of seasonality, was analyzed recordings made in the dry and rainy, and the other studies, was analyzed the data of the rainy season. In the analysis of vocal variation, we used only the songs, because of its importance to reproduction. The parameters tested were number of notes, duration of song, lowest and highest frequency, frequency range, peak-frequency and song rate. The vocal repertoire was varied among the species studied, B. flaveolus repertoire has one song and one call and B. hypoleucus repertoire has one song and three calls. Basileuterus leucophrys repertoire was the largest and most complex, with two songs and nine calls, including some simultaneous emission of sounds with different characteristics originating on either side of the syrinx (two-voice). Most of the vocal parameters of each species are similar to reviously in the literature to the microhabitats occupied by them. All species altered their vocalizations according to factors established and showed characteristic songs for each level of the factors tested. Thus, is possible to conclude that the three species of Basileuterus spp. have vocal repertoire of varied size and complexity, and in front of natural and antropogenic factors, these species are able to vary their vocalizations. / A comunicação vocal das aves está diretamente relacionada com comportamentos vitais. Com isso, algumas espécies mostram-se extremamente sensíveis às alterações nas características sonoras das vocalizações. Passeriformes Oscines, por possuírem siringe mais complexa e capacidade de aprendizagem vocal, são o grupo com maior condição de apresentar variações vocais. Neste estudo foram escolhidas três espécies simpátricas e parcialmente sintópicas de Passeriformes Oscines, Parulidae: Basileuterus flaveolus, B. hypoleucus e B. leucophrys, com o objetivo de caracterizar o repertório vocal destes Basileuterus spp., e verificar se essas espécies alteram os parâmetros vocais de seus cantos devido aos fatores sazonalidade, distribuição entre fragmentos e maior intensidade de ruído ambiental. O trabalho foi realizado no município de Uberlândia, MG, em fragmentos de floresta estacional semidecidual no bioma Cerrado. Para a caracterização do repertório vocal e verificar o efeito da sazonalidade, foram analisadas gravações feitas nas estações seca e chuvosa e para os demais estudos, foram analisados os dados da estação chuvosa. Nas análises de variação vocal, foram utilizados apenas os cantos, devido sua importância reprodutiva. Os parâmetros testados foram o número de notas, a duração do canto, a menor e a maior frequência, a amplitude de frequência, a máxima frequência e a taxa de emissão de notas. O repertório vocal foi bastante variado entre as espécies estudadas, B. flaveolus apresentou um tipo de canto e um tipo chamado e B. hypoleucus apresentou um tipo de canto e três tipos de chamados. Basileuterus leucophrys foi o que teve o maior e mais complexo repertório, com dois tipos de cantos e nove tipos de chamados. Essa maior complexidade deveu-se a emissão simultânea de sons com características distintas, originários de cada lado da siringe (two-voice), tanto para os dois tipos cantos quanto para alguns tipos de chamados. Foi possível verificar que a maioria dos parâmetros vocais de cada espécie, se assemelha aos padrões pré-estabelecidos pela literatura, para os microhabitats ocupados por elas. Todas as espécies alteraram suas vocalizações diante dos fatores sazonalidade, distribuição entre fragmentos e intensidade do ruído ambiental ao ponto de apresentarem cantos característicos para cada nível dos fatores testados. Com isso, é possível concluir que as três espécies de Basileuterus, têm repertório vocal de variado tamanho e complexidade e que diante de fatores naturais e antrópicos, essas espécies são capazes de variar suas vocalizações. / Mestre em Ecologia e Conservação de Recursos Naturais
16

RUÍDO EM SANTA MARIA - RS A CONTRIBUIÇÃO DO TRÁFEGO VEICULAR EM ÁREA MISTA (Residencial/ Comercial)

Mendonça, Elizeu Carneiro de 26 February 2009 (has links)
The urban noise generated by traffic is shown as being one of the strong means of environmental pollution. It is known that its influence on the people facilitates unhealthy damages. This work tries to contribute with that theme, through measure of urban noise levels in road with great flow characterized as mixed area (commercial / residential) in Santa Maria's city central area - RS. For the evaluation of sound levels it was chosen two measure points whose adopted approach was the high number of vehicles that to transit for the road, besides buses. The level of sound pressure (LAeq) was evaluated, in useful and in week ends days, in shifts defined starting from a previous measure, whose data collection happened among the months of December of 2007 to June of 2008, been the measures driven with the equipment model SOLO, Type 01. Both measured points present different characteristics in terms of relief and urban equipments, due to the topography and traffic signalizations points. As a conclusion of this work, it was observed that largest LAeq obtained in all the measures was 73,3 dB(A) in the Measure Point 01, in the shift of the end of the evening / late afternoon. This shift concentrated on all the evaluations, the largest results. / O ruído urbano gerado por trânsito mostra-se como sendo um dos fortes meios de poluição ambiental. Sabe-se que sua influência sobre as pessoas possibilita danos. O trabalho procura contribuir com esse tema, através de medições de níveis de ruído urbano em via com grande fluxo viário caracterizada como área mista (comercial/ residencial) na região central de Santa Maria RS. Para a avaliação de níveis sonoros foram escolhidos dois pontos de medição localizados na mesma via, mas com situações de relevo e de tipo de trajeto diferenciados, mas com elevado número de veículos que transitam pela via, inclusive ônibus. Avaliou-se o nível de pressão sonora (LAeq), em dias úteis e em finais de semana, em turnos definidos a partir de uma medição prévia. Além dos dados acústicos, realizou-se um detalhado estudo para a identificação da contribuição do ruído veicular. Foram levantados os dados de tráfego, como a quantificação e a caracterização dos tipos de veículos (leves e pesados). Concluiu-se que o maior LAeq foi de 73,3 dB(A) e que, em todas as medições realizadas, o turno referente ao final de tarde/entardecer caracterizou os maiores resultados.
17

Modeling Continental-Scale Outdoor Environmental Sound Levels with Limited Data

Pedersen, Katrina Lynn 13 August 2021 (has links) (PDF)
Modeling outdoor acoustic environments is a challenging problem because outdoor acoustic environments are the combination of diverse sources and propagation effects, including barriers to propagation such as buildings or vegetation. Outdoor acoustic environments are most commonly modeled on small geographic scales (e.g., within a single city). Extending modeling efforts to continental scales is particularly challenging due to an increase in the variety of geographic environments. Furthermore, acoustic data on which to train and validate models are expensive to collect and therefore relatively limited. It is unclear how models trained on this limited acoustic data will perform across continental-scales, which likely contain unique geographic regions which are not represented in the training data. In this dissertation, we consider the problem of continental-scale outdoor environmental sound level modeling using the contiguous United States for our area of study. We use supervised machine learning methods to produce models of various acoustic metrics and unsupervised learning methods to study the natural structures in geospatial data. We present a validation study of two continental-scale models which demonstrates that there is a need for better uncertainty quantification and tools to guide data collection. Using ensemble models, we investigate methods for quantifying uncertainty in continental-scale models. We also study methods of improving model accuracy, including dimensionality reduction, and explore the feasibility of predicting hourly spectral levels.
18

Modeling Continental-Scale Outdoor Environmental Sound Levels with Limited Data

Pedersen, Katrina Lynn 01 January 2021 (has links) (PDF)
Modeling outdoor acoustic environments is a challenging problem because outdoor acoustic environments are the combination of diverse sources and propagation effects, including barriers to propagation such as buildings or vegetation. Outdoor acoustic environments are most commonly modeled on small geographic scales (e.g., within a single city). Extending modeling efforts to continental scales is particularly challenging due to an increase in the variety of geographic environments. Furthermore, acoustic data on which to train and validate models are expensive to collect and therefore relatively limited. It is unclear how models trained on this limited acoustic data will perform across continental-scales, which likely contain unique geographic regions which are not represented in the training data. In this dissertation, we consider the problem of continental-scale outdoor environmental sound level modeling using the contiguous United States for our area of study. We use supervised machine learning methods to produce models of various acoustic metrics and unsupervised learning methods to study the natural structures in geospatial data. We present a validation study of two continental-scale models which demonstrates that there is a need for better uncertainty quantification and tools to guide data collection. Using ensemble models, we investigate methods for quantifying uncertainty in continental-scale models. We also study methods of improving model accuracy, including dimensionality reduction, and explore the feasibility of predicting hourly spectral levels.
19

Le bruit environnemental en milieu urbain : exposition d'une population d'enfants et performances scolaires / Exposure to noise an school performance of children living in a urban area

Pujol, Sophie 20 December 2012 (has links)
La relation entre exposition sonore environnementale et performance scolaire a été étudiée auprès des 900 élèves scolarisés en CE2 en 2006-2007 dans les écoles publiques de la ville de Besançon (120 000 habitants). Un questionnaire, complété par les familles de 724 élèves a permis de localiser les habitations et recueillir les facteurs associés à leur réussite ou échec scolaire.L'exposition sonore de cette population a été évaluée par deux approches complémentaires : une campagne de mesure, conduite au domicile de 44 enfants pendant 8 jours consécutifs (niveaux sonores intra- et extra-domiciliaires) ; une carte stratégique de bruit, à l'échelle de la ville (niveaux sonores en façade des écoles et du domicile de chacun des élèves). Ces niveaux sonores ont été confrontés aux résultats obtenus lors des évaluations diagnostiques de l'Education nationale, organisées à l'entrée en CE2, à l'aide de modèles de régressions linéaires multi-niveaux. Un lien significatif entre niveau d'exposition sonore en façade de l'école et baisse des scores obtenus en français et mathématiques a été mis en évidence, y compris après ajustement sur les facteurs de confusion. La tendance est similaire entre niveau sonore en façade du domicile et score en français, bien qu'en limite de signification après ajustement sur les cofacteurs.Ce travail s'inscrit dans une démarche pluridisciplinaire d'évaluation du risque environnemental, avec un accent particulier porté sur l'évaluation de l'exposition. L'évaluation de l'impact des nuisances sonores sur la santé est d'autant plus importante que l'exposition sonore environnementale concerne une large part de la population, en Europe et dans le monde / The aim of this thesis was to quantify children's exposure to environmental ambient noise at home and at school and to assess the relation between noise exposure and school performance of 8-9 year-old-schoolchildren. This study was conducted among the 900 children living in a 120, 000 inhabitants city and attending one of the 35 public primary schools in key stage 2, year 4 in 2006-2007. Questionnaires were distributed to the families to locate the children's home and collect data on potential confounding factors associated with school achievement or failure. These questionnaires were completed by 724 families living in the city.A noise measurement campaign was performed at the residence of 44 randomly sampled schoolchildren (outdoor and indoor noise levels during one week) and a strategic noise map was built at the city scale to calculate the outdoor environmental ambient noise levels at home and at school. These noise levels were compared with the children's school performance at the national standardised assessment test in French and mathematics. A linear exposure-effect relation between noise exposure at school and impaired Mathematics score was found after adjustment for confounding factors. Furthermore, both the ambient noise exposure at school and at home individually considered were found to be associated with an impaired children French performance.This study mainly focused on the assessment of the noise exposure in an urban area. The magnitude of the effect we observed on school performance may seem to be modest, but, when considering the number of people potentially chronically exposed to similar environmental noise levels, this effect may be of importance.
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Mapeamento e análise de ruído ambiental estudo de caso: Campus Unisinos

Krumenauer, Marcelo 09 August 2016 (has links)
Submitted by Silvana Teresinha Dornelles Studzinski (sstudzinski) on 2016-12-15T15:05:04Z No. of bitstreams: 1 Marcelo Krumenauer_.pdf: 69569589 bytes, checksum: e2523784eadef427213d4da3ae49eb6f (MD5) / Made available in DSpace on 2016-12-15T15:05:05Z (GMT). No. of bitstreams: 1 Marcelo Krumenauer_.pdf: 69569589 bytes, checksum: e2523784eadef427213d4da3ae49eb6f (MD5) Previous issue date: 2016-08-09 / UNISINOS - Universidade do Vale do Rio dos Sinos / Os mapas de ruído ou cartas acústicas são amplamente difundidos entre os países da União Europeia e são importantes ferramentas para elaboração de planos de ação e metas para combater a poluição sonora. No Brasil, contudo, poucas são as ações efetivas para a identificação e avaliação das condições de exposição da população ao ruído real. O conhecimento dos níveis reais de ruído permite ao poder público a análise e proposição de medidas e políticas públicas. Nos centros urbanos, cada vez mais a população sofre devido aos efeitos dos elevados níveis de ruídos, principalmente decorrentes do tráfego viário, degradando o meio ambiente e as condições de vida da população. O objetivo do trabalho é desenvolver o mapa de ruído para o Campus da Universidade do Vale do Rio dos Sinos. Para desenvolver este objetivo, foi utilizado o software de previsão acústica CadnaA, aplicando-se os seguintes procedimentos metodológicos: definição da área de estudo; estudo de tráfego da área avaliada (utilizando-se a contagem automática de veículos, através de controladores eletrônicos e cancelas automáticas do Campus); definição de grandezas (meteorológicas, acústicas, tráfego e geométricas); definição de parâmetros de cálculo; modelagem sonora; e validação do ambiente simulado. Para validação do mapa de ruído do Campus, foram avaliados 13 diferentes modelos, com diferentes configurações, comparando-os com os níveis equivalentes de pressão sonora coletados em campo. Os resultados finais indicam um modelo calibrado para a representação do ambiente sonoro do Campus, que com grande diversidade de ambientes de propagação, diferencia-se dos demais ambientes urbanos. Este trabalho justifica-se pelo avanço no reconhecimento e quantificação de níveis de ruídos em áreas externas. / The noise maps or acoustic cards are widely disseminated among of the European Union countries and are important tools for preparing action plans and targets to combat noise pollution. In Brazil, however, there are few effective actions for the identification and evaluation of the conditions of exposure of the population to the real noise. Knowledge of the actual levels of noise allows the government to analyze and propose measures and public policies. In urban centers, increasingly people are suffering from the effects of high noise levels, mainly resulting from road traffic, degrading the environment and living conditions of the population. The objective is to develop a noise map for the Campus of the Universidade do Vale do Rio dos Sinos. To develop this goal, the acoustic prediction software CadnaA was used, applying the following methodological procedures: definition of the study area; the evaluated area traffic study (using the automatic counting of vehicles through electronic controllers and automatic Campus gates); defining quantities (weather, acoustics, traffic and geometric); setting calculation parameters; sound modeling; and validation of the simulated environment. To validate the Campus noise map were evaluated 13 different models, with different settings, comparing them with the equivalent sound pressure level collected in the field. The final results indicate a calibrated model for the representation of the Campus environment sound, which with great diversity of propagation environments, differs from other urban environments. This work is justified by the progress in the recognition and measurement of noise levels outdoors.

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