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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.
31

Work zone crash analysis and modeling to identify factors associated with crash severity and frequency

Dias, Ishani Madurangi January 1900 (has links)
Doctor of Philosophy / Civil Engineering / Sunanda Dissanayake / Safe and efficient flow of traffic through work zones must be established by improving work zone conditions. Therefore, identifying the factors associated with the severity and the frequency of work zone crashes is important. According to current statistics from the Federal Highway Administration, 2,372 fatalities were associated with motor vehicle traffic crashes in work zones in the United States during the four years from 2010 to 2013. From 2002 to 2014, an average of 1,612 work zone crashes occurred in Kansas each year, making it a serious concern in Kansas. Objectives of this study were to analyze work zone crash characteristics, identify the factors associated with crash severity and frequency, and to identify recommendations to improve work zone safety. Work zone crashes in Kansas from 2010 to 2013 were used to develop crash severity models. Ordered probit regression was used to model the crash severities for daytime, nighttime, multi-vehicle and single-vehicle work zone crashes and for work zones crashes in general. Based on severity models, drivers from 26 to 65 years of age were associated with high crash severities during daytime work zone crashes and driver age was not found significant in nighttime work zone crashes. Use of safety equipment was related to reduced crash severities regardless of the time of the crash. Negative binomial regression was used to model the work zone crash frequency using work zones functioned in Kansas in 2013 and 2014. According to results, increased average daily traffic (AADT) was related to higher number of work zone crashes and work zones in operation at nighttime were related to reduced number of work zone crashes. Findings of this study were used to provide general countermeasure ideas for improving safety of work zones.
32

Adolescentes, estudantes de período noturno: como se alimentam e gastam suas energias / Teens, students nighttime, how they feed and spend their energies

Ana Maria Dianezi Gambardella 09 January 1996 (has links)
Com o objetivo de conhecer a prática alimentar, a atividade fÍsICA e o gasto energético de adolescentes, de ambos os sexos, inseridos ou não no mercado de trabalho, administraram-se questionários auto-aplicáveis a 273 estudantes, do período noturno, de seis escolas da Rede Estadual de Ensino de Santo André - SP. Estudantes trabalhadores (163) , ou seja, que recebiam remuneração por serviços prestados, mantinham-se em atividades ocupacionais pelo período de 40 a 50 horas semanais, percebendo de 1 a 3 salários mínimos por mês. Os meninos participavam, proporcionalmente, mais no mercado de trabalho formal que as meninas. Foram relatadas todas as atividades fisicas desempenhadas segundo número de dias por semana e horas por dia. Entre as várias atividades discriminadas, destacou-se assistir televisão, como prática comum a todos os estudantes, independentemente de gênero e de inserção ou não no trabalho. Outras atividades assinaladas mostraram-se estatisticamente independentes do fato de trabalhar ou não, porém, foi detectada, para algumas, associação com gênero, tais como prática esportiva (meninos) e afazeres domésticos (meninas) . O gasto energético diário referente à atividade física foi estimado com base nos diferentes movimentos, ponderados por tempo e nos fatores atividades da FAO/OMS/UNU. Os valores encontrados foram 3150 e 2160 Cal para estudantes masculinos e femininos, respectivamente. A prática alimentar foi analisada sob o aspecto qualitativo da dieta habitual, utilizando, como padrão, uma adaptação do Food Guide pyramid. Não foram observadas associações estatisticamente significativas entre trabalhar e apresentar dieta inadequada para os grupos de alimento de carnes e de cereais, ao contrário do verificado entre os grupos de frutas e de verduras, cujo teste estatístico indicou haver associação. / A group of 273 students of evening courses of 6 State Public schools, located in the city of Santo André, State of São Paulo, Brazil, was analyzed, aiming to know their dietary practices, physical activities and energy expenditures. One hundred and sixty three adolescents were workers and their occupational activities last for 40 to 50 hours per week; they earned from 1 to 3 living wages. Proportionally, male adolescents were more engaged in the formal workmanship than girls. All their physical activities were described and draw the attention \"watching TV\" as the most frequent for both sexes and workers or not. Other activities were statistically associated to gender but independent to the fact of being a worker (boys were more related to sports and girls to housekeeping). The daily energy expenditure related to physical activities was calculated based on the FAO/WHO/UNU movement-factors indicators, and the values of 3000 and 2100 Cal were estimated for boys and girls, respectively. Dietary practices, by the point of view of quality, were analyzed, using one adaptation of the Food Guide Pyramid. Statistical association was not found between inadequate diets and workers when meat and cereals were observed; the opposite occurred when fruits and vegetables were taken in account, statistical association was detected.
33

CONTROLE ESTATÍSTICO DA QUALIDADE NA IRRIGAÇÃO POR ASPERSÃO / STATISTICAL CONTROL OF QUALITY IN THE SPRINKLER IRRIGATION

Frigo, Jiam Pires 02 June 2014 (has links)
Made available in DSpace on 2017-07-10T19:23:55Z (GMT). No. of bitstreams: 1 Jiam Pires_ Frigo.pdf: 2243207 bytes, checksum: 76a818d3ba4a98ecda459c13486050ca (MD5) Previous issue date: 2014-06-02 / The sprinkler irrigation system is widely used because of the possibility of high uniform distribution and to adapt itself to different crops and soils. On the other hand, the water uniform application in irrigation is affected by meteorological factors that decrease the system efficiency. There has always been some concern about the quality of products and services in human history, since all products should have desirable characteristics to be accepted by consumers. Currently, development, improvement and monitoring of new management models quality during the production process have become essential for many organizations. Thus, inspection control has enhanced by statistical techniques, losses have been decreased and it was possible to stimulate some trading competition. In this context, this study aimed at evaluating the irrigation system in a conventional sprinkler using the Christiansen Uniformity Coefficient (CUC) and the index Process Capability (CP) to correlate techniques with the system efficiency as well as verify the wind influence on irrigation by Shewhart control chart and compare the results of Shewhart control charts use with the EWMA and tabular CUSUM control charts, applied in quality control of the conventional sprinkler irrigation. In this study, 60 essays were carried out on a four irrigation sprinklers system, Xcel-Wobbler model, 1.0 m height above soil and 6.0 x 6.0 m spaced. The collectors were 1.0 m spaced apart with 0.5 m height from soil. The service pressure was monitored and appropriate to the sprinklers specifications, while wind was monitored in situ by a 2.0 m high digital anemometer. In order to evaluate the system, Christiansen Uniformity Coefficient (CUC), the index Process Capability (CP), Shewhart charts (Xbarra) and the charts of exponentially weighted moving average (EWMA) and cumulative sum (CUSUM) were used. The irrigation sprinkler system showed the best performance and was under control when the average wind speed was less than 1.0 m s-1. The use of individual Shewhart control charts visually allowed affirming that wind has a direct influence on CUC. Night irrigation showed less variability on the studied data, when compared to daytime ones and this has resulted in greater efficiency in irrigation. The CPi index showed great similarity with the Christiansen Uniformity Coefficient (CUC). It proved to be very sensitive to efficiency sprinkler (Ea) variation and able to indicate the quality of sprinkler irrigation. The EWMA chart, when compared to the control charts, was susceptible when used in autocorrelated data, according to the occurrence of false alarms. But, to the residue data without autocorrelation (the ARIMA model), the CUSUM tabular chart was more sensitive to detect variations in irrigation due to wind speed, when compared to EWMA and Shewhart charts for the same data. In sprinkler irrigation, when there is a relation between CUC and wind speed, the Shewhart chart was more indicated by simplicity, reliability and ease of interpretation, even in the presence of autocorrelated data. / O sistema de irrigação por aspersão é muito utilizado, devido à possibilidade de elevada uniformidade de distribuição e por adaptar-se às diversas culturas e solos. Porém, a uniformidade de aplicação de água nas irrigações é afetada por fatores meteorológicos que diminuem a eficiência do sistema. A preocupação com a qualidade de produtos e serviços oferecidos sempre esteve presente na história da humanidade, pois para que os produtos fossem aceitos, deveriam possuir características desejáveis pelos consumidores. Atualmente, com o surgimento de novos modelos gerenciais, a melhoria e o monitoramento da qualidade durante o processo de produção tornaram-se uma necessidade para muitas organizações. Assim, aprimorou-se o controle da inspeção por meio de técnicas estatísticas, reduziram-se perdas e foi possível competir no mercado. Neste contexto, o objetivo deste estudo foi avaliar a irrigação em um sistema por aspersão convencional, utilizando o Coeficiente de Uniformidade de Christiansen (CUC), o índice de Capacidade do Processo (CP) para correlacionar as técnicas com a eficiência do sistema, verificar a influência do vento na irrigação pelo gráfico de controle de Shewhart e confrontar os resultados da utilização dos gráficos de controle de Shewhart, com os gráficos de controle MMEP e CUSUM tabular, aplicados no controle de qualidade da irrigação por aspersão convencional. Neste estudo, foram realizados 60 ensaios em um sistema de irrigação por aspersão convencional. O sistema era constituído de quatro aspersores, modelo Xcel-wobbler, altura de 1,0 m em relação ao solo e espaçamento de 6,0 x 6,0 m. Os coletores foram espaçados em 1,0 m entre si com altura de 0,5 m do solo. A pressão de serviço foi monitorada e adequada às especificações dos aspersores, e o vento monitorado in loco, por um anemômetro digital com 2,0 m de altura. Para a avaliação do sistema, foram utilizados o Coeficiente de Uniformidade de Christiansen (CUC), o índice de Capacidade do Processo (CP), gráficos de Shewhart (Xbarra) e os gráficos de média móvel exponencialmente ponderada (MMEP) e de soma cumulativa (CUSUM). O sistema de irrigação por aspersão convencional teve melhor desempenho e esteve sob controle, quando a velocidade média do vento esteve menor que 1,0 m s-1. O uso dos gráficos individuais de controle de Shewhart possibilitou afirmar visualmente que o vento tem influência direta sobre o CUC. A irrigação noturna apresentou menor variabilidade nos dados, quando comparados aos dados do período diurno e isso resultou em maior eficiência na irrigação. O índice CPi teve grande similaridade com o Coeficiente de Uniformidade de Christiansen (CUC); mostrou-se bastante sensível à variação da eficiência de aspersão (Ea) e capaz de indicar a qualidade da irrigação por aspersão. Em comparação aos gráficos de controle, o gráfico MMEP mostrou-se suscetível quando utilizado em dados autocorrelacionados, pelas ocorrências de alarmes falsos. Para dados de resíduos, sem autocorrelação (pelo modelo ARIMA), o gráfico CUSUM tabular foi mais sensível ao detectar as variações ocorridas na irrigação devido à velocidade do vento, quando comparado aos gráficos MMEP e Shewhart para os mesmos dados. Na irrigação por aspersão, relacionando CUC com velocidade do vento, o gráfico de Shewhart foi mais indicado pela simplicidade, confiabilidade e facilidade de interpretação, mesmo na presença de dados autocorrelacionados entre si.
34

Towards the Use of Satellite Data in Security Policy-Related Prediction

Jayaweera, Mary Chrishani January 2021 (has links)
Inadequate economic data makes it more difficult for its incorporation in security-policy related prediction and there is a need for alternative datasets. Satellite data, more specifically nighttime lights data, can be used as a proxy for the economy. In this project, the correlation between nighttime lights and the economy between 1992 and 2018 is explored for five countries in Africa: Nigeria, Libya, the Central African Republic, the Republic of the Congo and Ghana. Data from two different satellite series, DMSP-OLS and VIIRS-DNB are used, and the extracted datasets are calibrated for the differences or intercalibrated. There was found to be a high correlation for two of the countries, the Republic of the Congo and Ghana. The biggest improvement can be made by developing the intercalibration method. A pitfall of the method is that it is not generally applicable as unique circumstances seen for Nigeria show in the correlation results.
35

Adaptive Frontbeleuchtungssysteme im Kraftfahrzeug: Ein Beitrag zur nächtlichen Verkehrssicherheit?: Adaptive Frontbeleuchtungssysteme im Kraftfahrzeug:Ein Beitrag zur nächtlichen Verkehrssicherheit?

Böhm, Michael 25 June 2013 (has links)
Da die menschliche Sehleistung bei geringer Beleuchtung stark vermindert ist, birgt die Teilnahme am nächtlichen Straßenverkehr besondere Gefahren. Sowohl Kraftfahrzeugführer als auch schwächere Verkehrsteilnehmer sind sich dieser Problematik offenbar nicht hinlänglich bewusst und verhalten sich häufig hochriskant. Dies hat, gemessen an der Exposition, eine überproportionale Häufigkeit und Schwere von Nachtunfällen zur Folge. Um dieser Situation zu begegnen, erscheinen neben konventionellen Präventionsmaßnahmen der Verkehrsüberwachung und -erziehung oder Eingriffen in die Verkehrsinfrastruktur auch neuartige fahrzeugtechnische Systeme geeignet. So wurden in den letzten Jahren Fahrerassistenzfunktionen entwickelt, welche mittels adaptiver Lichtsteuerung die Ausleuchtung des Verkehrsraumes verbessern sollen. Hierfür wird das lichttechnische Signalbild anderer Fahrzeuge mittels einer Kamera erfasst und die eigene Scheinwerferlichtverteilung so angepasst, dass die Straße maximal ausgeleuchtet wird, um die Hinderniserkennung zu verbessern und trotzdem gleichzeitig eine Blendung anderer Kraftfahrer zu vermeiden. Als zusätzlich integrierte Funktion kommt auch eine automatisierte Fernlichtschaltung zum Einsatz. Bislang war nicht belegt, ob diese sogenannten Adaptiven Frontbeleuchtungssysteme (AFS) in der Lage sind, tatsächlich zu einer Erhöhung der nächtlichen Verkehrssicherheit beizutragen. Ziel der vorliegenden Arbeit war es, Anforderungen zur Blendungsvermeidung beim Einsatz derartiger Assistenzfunktionen aufzustellen und die Wirksamkeit adaptierter Scheinwerferlichtverteilungen zu bewerten. Hierfür wurden entsprechende empirische Untersuchungen durchgeführt. So konnten in der ersten Studie Blendungsgrenzwerte ermittelt werden, welche sicherstellen sollen, dass andere Verkehrsteilnehmer nicht über das bislang übliche Maß hinaus durch die Scheinwerfer geblendet werden, wenn neuartige AFS zum Einsatz kommen. In einem weiteren Experiment wurde geprüft, ob unter Einhaltung dieser Grenzwerte eine nennenswerte Erhöhung der Erkennbarkeitsentfernungen für schlecht sichtbare Hindernisse auf der Straße erreichbar ist. Die letzte Studie beschäftigte sich mit der Frage, in welchem Umfang adaptierte Lichtverteilungen im realen Straßenverkehr zum Einsatz kämen, um deren mögliche Wirksamkeit besser beurteilen zu können. Parallel hierzu wurde auch das Fernlichtnutzungsverhalten der Probanden untersucht. Wie die durchgeführten Untersuchungen zeigen konnten, ergeben sich durch den Einsatz adaptierter Lichtverteilungen signifikante Verbesserungen bezüglich der Erkennbarkeit von Hindernissen gegenüber konventioneller Kraftfahrzeugbeleuchtung in teils beträchtlichem Ausmaß. Außerdem konnte ermittelt werden, dass adaptierte Scheinwerferlichtverteilungen im realen Straßenverkehr in erheblichem Umfang zum Tragen kämen. Aufgrund der viel zu geringen Fernlichtnutzung könnten Kraftfahrer auch besonders stark von der automatisierten Fernlichtschaltung profitieren. Damit kann davon ausgegangen werden, dass neuartige AFS tatsächlich überaus geeignet sind, nächtliche Kollisionen von Kraftfahrzeugen mit unbeleuchteten schwächeren Verkehrsteilnehmern oder Wild zu vermeiden. Trotz dieser Einschätzung sind die letztlich zu erwartenden positiven Auswirkungen auf die Verkehrssicherheit womöglich eher gering, wenn es nicht gelingt, alle Verkehrsteilnehmer für die Gefahren des nächtlichen Straßenverkehrs zu sensibilisieren. Zudem können Adaptive Frontbeleuchtungssysteme selbstverständlich nicht allen Ursachen nächtlicher Kollisionen mit Hindernissen auf der Straße wirkungsvoll begegnen. / Since the human visual performance is substantially degraded under low illumination levels participating in nighttime traffic is particularly dangerous. Drivers as well as vulnerable road users are not sufficiently aware of this and therefore expose themselves to severe risks. Compared to overall exposure, a disproportionately high number of severe injuries and fatalities occur in nighttime traffic. Besides conventional approaches such as enforcement, education, and infrastructural measures, new automotive systems promise additional gains in road safety. Recently, Adaptive Frontlighting Systems (AFS) have been developed that are meant to improve road illumination in front of the car. Therefore, other lit vehicles are detected by a camera, which allows adapting the beam pattern according to the traffi c situation. The maximum of illumination is directed at the road to enhance object detection while omitting oncoming traffic to prevent glare to other drivers. This functionality also includes high beam automation. Up to now it has not been convincingly substantiated if so-called AFS are actually capable of increasing road safety. Thus, the aim of this thesis was to set up system specifications for the prevention of glare and to assess the impact of adapted light distributions by conducting adequate empirical studies. The first study identified illuminance thresholds in order to assure that other drivers will not suffer from glare when AFS are applied that are beyond present levels caused by regular low beams. The second experiment examined if the adaptation of beam patters within these identified limits improves detection distances for unlit obstacles on the road. The last study examined the extent of AFS’ applicability in real nighttime traffic, to better estimate the possible efficacy of such systems. The high beam usage behavior of the test subjects was also analyzed within this driving study. Adapted beam patterns turned out to significantly improve obstacle detection in comparison to conventional low beams. It was found that adaptive lighting functions could cover a substantial part of time driven in rural areas. Besides, high beam automation could dramatically increase high beam usage since drivers mostly fail to maintain manual switching. Taking these findings into consideration AFS seem to be suited to prevent collisions with unlit obstacles during nighttime driving. However, their impact on road safety could remain marginal unless road users are sensitized for the dangers of participating in traffic during darkness. Moreover, AFS cannot counteract all causes of nighttime collisions.
36

Jämlik traumavård vid en traumaenhet : En retrospektiv studie om skillnader mellan traumapatienter beroende på tid på dygnet, kön och ålder / Equal trauma care at a trauma unit : A retrospective study on differences between trauma patients depending on time of the day, sex and age

Hernerud, Oskar, Qvarfordt, Malin January 2023 (has links)
Bakgrund: Trauma är en av de mest bidragande orsakerna till skada och död globalt. För att minska lidande och död hos patienter samt kostnader för samhället krävs en välfungerande traumavård. Tiden på dygnet, kön och ålder kan påverka utfallet för patienter som inkommer till sjukhus efter ett trauma. Eftersom forskningen inte är enig är detta ett område som ytterligare måste undersökas. Syftet med studien var att undersöka skillnader mellan traumapatienter vid en traumaenhet beroende på om patienten inkommer dagtid respektive jourtid, kön och ålder. Metod: Studien är en retrospektiv icke-experimentell tvärsnittsstudie där redan insamlade från en traumakoordinator vid ett sjukhus i norra sjukvårdsregionen analyserats. Studiepopulationen bestod av 115 patienter som blivit inskrivna som trauma nivå 1 eller 2 på akutmottagningen under år 2022. Data har analyserats med T-test och Chi-2 test för att undersöka eventuella skillnader och för att undersöka samband har Pearson’s korrelationstest använts. Signifikansgränsen sattes till P<0,05. Resultat: I denna studie kunde inga signifikanta skillnader identifieras mellan de trauman som inkom på dagtid och på jourtid gällande tid till vård eller allvarlighetsgrad av skadan. Kvinnor hade signifikant kortare tid mellan larm och ankomsttid till sjukhus. Det fanns ingen signifikant skillnad i allvarlighetsgrad beroende på tid på dygnet. Det fanns inte heller någon skillnad i allvarlighetsgrad mellan könen men det fanns ett positivt samband mellan hög ålder och allvarlighetsgrad. Slutsats: Vården vid det valda sjukhuset skiljer sig inte signifikant i traumaomhändertagande på dagtid och jourtid eller mellan könen vilket utifrån studerade variabler kan indikera en jämlik vård. Vidare studier skulle vara av intresse för att med andra variabler och infallsvinklar studera eventuella skillnader. Det finns också ett behov av jämförande analyser mellan sjukhus för att undersöka närmare hur jämlik vård som bedrivs i landet. Kunskapen är av vikt för anestesisjuksköterskan för att bedriva jämlik vård.

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