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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.
1

Asthma in school age : prevalence, incidence and remission in relation to environmental determinants. The Obstructive Lung Disease in Northern Sweden (OLIN) Studies, Thesis XI

Andersson, Martin January 2013 (has links)
Background In the past half-century, the prevalence of asthma among children and adolescents has risen and asthma has become an important public health challenge in Sweden as well as in many other countries, necessitating further studies on this complex disease and its risk factor pattern. The studies included in this thesis aimed to investigate the clinical expression of childhood asthma over time, to describe the determinants of new-onset and remission of asthma, and to evaluate possible environmental risk factors in northern Sweden. Methods As the result of a repeated questionnaire survey among primary school children aged 7-8 years in three municipalities in the north of Sweden, two pediatric cohorts were formed, one in 1996 (n=3430) and one in 2006 (n=2585). The cohort created in 1996 was followed annually until the age of 19 years. Skin prick testing was performed on children in both cohorts. Lung function and bronchial hyperreactivity testing were carried out in children with asthma in the first cohort. The study participation and retention rates were very high in both cohorts. Among children in the second cohort living in Luleå, the home addresses were assigned to coordinates in a geographical information system (GIS) to evaluate the impact on respiratory health of living near roads with much traffic, which was measured as the number of vehicles daily. We used a validated reported diagnosis of asthma and International Study of Asthma and Allergies in Childhood (ISAAC) questions were incorporated into the questionnaire. A cross-sectional study of children of the same age ten years apart, longitudinal studies on asthma incidence and remission as well as a cross-sectional study on vehicle traffic were performed. Results While children aged 7-8 years in 2006 more often had a physician-diagnosed asthma compared to children of the same age in 1996 (7.4% vs 5.7%, p<0.001), they had less asthma symptoms, especially severe symptoms. In parallel, a more beneficial environment and a more intense treatment with inhaled corticosteroids (ICS) were observed. The explanation for this change in clinical expression probably includes also an increased awareness and diagnosing of asthma. From age 12 years to age 19 years, the cumulative incidence of physician-diagnosed asthma was 7.2% and of current wheeze 22.0%. The risk of new-onset asthma in adolescence was increased among girls, sensitized and those with heredity for asthma. Smoking and home dampness increased the risk for incident wheeze. The risk for both incident asthma and wheeze was inversely related to number of siblings. Among children with current asthma at age 7-8 years, 21% were in remission, 38% had periodic asthma and 41% had persistent asthma at a follow-up at age 19 years. Subjects in remission and with periodic asthma had significantly less airway obstruction and showed less bronchial hyperreactivity compared to subjects with persistent asthma. The probability of asthma remission from childhood to early adulthood was significantly increased by absence of allergic sensitization, male gender and a low asthma severity scoring at age 7-8 years. Sensitization to furred animals was more important as a determinant of both incidence and remission than sensitization to pollen. Living close to roads with high traffic flows, especially with heavy vehicles, was associated with an increased risk for current wheeze. Stratified analyses showed that the effect of traffic on asthma and wheeze was restricted to non-sensitized subjects. Conclusion Asthma onset in adolescence was more common among girls and remission was more common among boys. Children sensitized to furred animals and children with a more severe asthma were risk groups for persistence of asthma. Environmental factors such as smoking and dampness were associated to onset of asthma symptoms during adolescence, and vehicle traffic was associated with asthma symptoms among children also in a small city with relatively low traffic flows. Preventive measures like smoking reduction programs, improvement of damp housing conditions and separation of areas where many children live from heavily trafficked roads could prove to be beneficial. / OLIN-studierna
2

Análise exploratória de método utilizando Wavelet para detecção de padrões e anomalias em dados históricos do tráfego veicular / Exploratory method analysis using Wavelet to detect patterns and anomalies in traffic history data

Ribeiro, Elaine Rodrigues 10 August 2017 (has links)
Este trabalho visa realizar uma análise exploratória de método utilizando Wavelet para analisar as variações na corrente de tráfego verificando simultaneamente os padrões no comportamento do tráfego e momentos atípicos, em diferentes escalas de tempo, através da Transformada Wavelet e métodos complementares em dados históricos do tráfego veicular. Os dados empíricos utilizados foram coletados separadamente para cada faixa de tráfego, em intervalos de curta duração (5 ou 6 minutos), em rodovias do estado de São Paulo. A partir desses dados, foram gerados os componentes de aproximação e detalhe da Transformada Wavelet Discreta de Haar. Os componentes gerados foram analisados e caracterizados antes de aplicar os métodos complementares. Para o reconhecimento de padrões no comportamento do tráfego foram utilizados os componentes de aproximação e a análise de agrupamento. Os resultados indicaram: (1) que existe grande tendência de classificar dias úteis típicos com terças, quartas e quintas-feiras, (2) a influência dos feriados na quantidade de agrupamentos, (3) a existência de diferentes efeitos para cada feriado e (4) influência do feriado de forma distinta a cada sentido da rodovia. Para detecção de momentos atípicos foram utilizados os coeficientes de detalhe e determinado um threshold em função do desvio padrão do coeficiente para determinar o que foi considerado como anomalia. Os resultados indicaram: (1) os primeiros níveis de decomposição apresentaram maior número de anomalias, (2) análises em sinais de período mensal concentraram mais anomalias do que a análise em um sinal de período anual, (3) a concentração de anomalias por tipo de dia está diretamente relacionada com o fluxo direcional e (4) identificou falhas no sensor. / This work aims to achieve an exploratory method analysis using Wavelet to analyze of traffic flow variations, evaluating both traffic behavior patterns and atypical moments, in different time scales, using Wavelet Transform and complementary traffic history data. Empirical data was collected separately for each traffic lane, in short intervals (5 or 6 minutes), in São Paulo state highways. The Haars Discrete Wavelet Transform approximation and detail components were generated from this collected data. These components were analyzed and characterized before using complementary methods. For pattern recognition in traffic behavior, approximation components were used, with cluster analysis. Results indicate that: (1) there is a great tendency in classifying work days in Tuesdays, Wednesdays and Thursdays, (2) holydays have influence in number of clusters, (3) each holyday have different effects and (4) holydays have different influences in each traffic direction. For the detection of atypical moments, detail coefficients were used with a determined threshold based on the standard deviation of said coefficient to define what was considered as an anomaly. Results indicate that: (1) the first levels of decomposition show a bigger number of anomalies, (2) monthly period signal analysis concentrate more anomalies than annual signals, (3) the anomaly concentration by each kind of day is directly related to traffic direction and (4) sensor flaws are identified.
3

Análise exploratória de método utilizando Wavelet para detecção de padrões e anomalias em dados históricos do tráfego veicular / Exploratory method analysis using Wavelet to detect patterns and anomalies in traffic history data

Elaine Rodrigues Ribeiro 10 August 2017 (has links)
Este trabalho visa realizar uma análise exploratória de método utilizando Wavelet para analisar as variações na corrente de tráfego verificando simultaneamente os padrões no comportamento do tráfego e momentos atípicos, em diferentes escalas de tempo, através da Transformada Wavelet e métodos complementares em dados históricos do tráfego veicular. Os dados empíricos utilizados foram coletados separadamente para cada faixa de tráfego, em intervalos de curta duração (5 ou 6 minutos), em rodovias do estado de São Paulo. A partir desses dados, foram gerados os componentes de aproximação e detalhe da Transformada Wavelet Discreta de Haar. Os componentes gerados foram analisados e caracterizados antes de aplicar os métodos complementares. Para o reconhecimento de padrões no comportamento do tráfego foram utilizados os componentes de aproximação e a análise de agrupamento. Os resultados indicaram: (1) que existe grande tendência de classificar dias úteis típicos com terças, quartas e quintas-feiras, (2) a influência dos feriados na quantidade de agrupamentos, (3) a existência de diferentes efeitos para cada feriado e (4) influência do feriado de forma distinta a cada sentido da rodovia. Para detecção de momentos atípicos foram utilizados os coeficientes de detalhe e determinado um threshold em função do desvio padrão do coeficiente para determinar o que foi considerado como anomalia. Os resultados indicaram: (1) os primeiros níveis de decomposição apresentaram maior número de anomalias, (2) análises em sinais de período mensal concentraram mais anomalias do que a análise em um sinal de período anual, (3) a concentração de anomalias por tipo de dia está diretamente relacionada com o fluxo direcional e (4) identificou falhas no sensor. / This work aims to achieve an exploratory method analysis using Wavelet to analyze of traffic flow variations, evaluating both traffic behavior patterns and atypical moments, in different time scales, using Wavelet Transform and complementary traffic history data. Empirical data was collected separately for each traffic lane, in short intervals (5 or 6 minutes), in São Paulo state highways. The Haars Discrete Wavelet Transform approximation and detail components were generated from this collected data. These components were analyzed and characterized before using complementary methods. For pattern recognition in traffic behavior, approximation components were used, with cluster analysis. Results indicate that: (1) there is a great tendency in classifying work days in Tuesdays, Wednesdays and Thursdays, (2) holydays have influence in number of clusters, (3) each holyday have different effects and (4) holydays have different influences in each traffic direction. For the detection of atypical moments, detail coefficients were used with a determined threshold based on the standard deviation of said coefficient to define what was considered as an anomaly. Results indicate that: (1) the first levels of decomposition show a bigger number of anomalies, (2) monthly period signal analysis concentrate more anomalies than annual signals, (3) the anomaly concentration by each kind of day is directly related to traffic direction and (4) sensor flaws are identified.
4

Automobilių transporto keliamo triukšmo tyrimas Alytaus mieste / Research of automobiles noise in Alytus city

Baliukonis, Ramūnas 07 June 2013 (has links)
Baigiamajame magistro darbe nagrinėjamas automobilių eismo keliamas triukšmas Alytaus mieste ir triukšmo poveikis žmogaus sveikatai bei gyvensenai. Atlikta mokslo publikacijų ir norminių dokumentų, reglamentuojančių triukšmo prevenciją bei triukšmo mažinimo priemones, analizė. Suformuluotas tyrimo tikslas ir iškelti tyrimo uždaviniai. Pateikiami triukšmo nustatymo pagrindiniai teoriniai aspektai. Suplanuotas eksperimentas, parinkta eksperimento atlikimo metodika bei automobilių keliamo triukšmo matavimo įranga. Triukšmo lygis išmatuotas 15-oje Alytaus miesto gatvių bei 5-iose sankryžose, vertinant važiuojančių automobilių srauto intensyvumą. Išmatuotas 5-ių automobilių įspėjamosios garso signalizacijos įtaisų keliamas triukšmas. Matavimai gatvėse ir sankryžose buvo atliekami dienos, vakaro ir nakties metu. Taikant lyginamosios analizės metodą, pateiktas skaičiavimų ir natūrinių matavimų rezultatų palyginimas, atliktas eksperimento rezultatų atitikties higienos normoms vertinimas. Regresinės bei koreliacinės analizės būdu nustatytas ryšio stiprumas tarp ekvivalentinio triukšmo lygio ir sunkvežimių procentinės dalies eismo sraute. Sudaryti Alytaus miesto triukšmingumo žemėlapiai, nustatytos triukšmingiausios ir tyliausios gatvės. Matematiškai apdorojus natūrinio eksperimento metu gautus rezultatus, pateiktos bendrosios išvados ir rekomendacijos. Darbą sudaro 9 dalys: įvadas, literatūros šaltinių ir pasaulinės patirties analizė, automobilių transporto triukšmo teorinis tyrimas... [toliau žr. visą tekstą] / The Master Thesis analyses road traffic noise in Alytus city and noise impacts on human health and lifestyle. Analysis of scientific publications and regulatory documents governing the prevention of noise and noise reduction measures is accomplished. The main theoretical aspects of noise detection are defined. Purpose of research is formulated and objectives of the research are raised. The field experiment was planned, the selection of experimental research methodology and car noise measurement equipment were made. Noise level was measured in 15 streets of Alytus city and on a 5 intersections considering the traffic intensity of passing automobiles. The noise of 5 automobiles acoustic warning devices are measured. Measurements in streets and intersections were performed during day, evening and night. The comparison of calculations and experimental research results are presented, the rating of experimental results and hygiene norm are performed by aiming the comparative analysis method. The relationship between the strength of the equivalent noise level and the percentage of trucks in the traffic are established by regression and correlation analysis. The noise level maps of Alytus city of the noisiest and the most silent streets are made. After mathematical processing of experimental results, general conclusions and recommendations are given. The work consists of nine parts: introduction, literature and world experience analysis, car traffic noise theoretical research, car... [to full text]
5

Monitorování dopravy z leteckých videí / Traffic Monitoring from Aerial Video Data

Babinec, Adam January 2015 (has links)
This thesis proposes a system for extraction of vehicle trajectories from aerial video data for traffic analysis. The system is designed to analyse video sequence of a single traffic scene captured by an action camera mounted on an arbitrary UAV flying at the altitudes of approximately 150 m. Each video frame is geo-registered using visual correspondence of extracted ORB features. For the detection of vehicles, MB-LBP classifier cascade is deployed, with additional step of pre-filtering of detection candidates based on movement and scene context. Multi-object tracking is achieved by Bayesian bootstrap filter with an aid of the detection algorithm. The performance of the system was evaluated on three extensively annotated datasets. The results show that on the average, 92% of all extracted trajectories are corresponding to the reality. The system is already being used in the research to aid the process of design and analysis of road infrastructures.

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