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Statistical Methods for Panel Studies with Applications in Environmental EpidemiologyYansane, Alfa Ibrahim Mouke 02 January 2013 (has links)
Pollution studies have sought to understand the relationships between adverse health effects and harmful exposures. Many environmental health studies are predicated on the idea that each exposure has both acute and long term health effects that need to be accurately mapped. Considerable work has been done linking air pollution to deleterious health outcomes but the underlying biological pathways and contributing sources remain difficult to identify. There are many statistical issues that arise in the exploration of these longitudinal study designs such as understanding pathways of effects, addressing missing data, and assessing the health effects of multipollutant mixtures. To this end this dissertation aims to address the afore mentioned statistical issues. Our first contribution investigates the mechanistic pathways between air pollutants and measures of cardiac electrical instability. The methods from chapter 1 propose a path analysis that would allow for the estimation of health effects according to multiple paths using structural equation models. Our second contribution recognizes that panel studies suffer from attrition over time and the loss of data can affect the analysis. Methods from Chapter 2 extend current regression calibration approaches by imputing missing data through the use of moving averages and assumed correlation structures. Our last contribution explores the use of factor analysis and two-stage hierarchical regression which are two commonly used approaches in the analysis of multipollutant mixtures. The methods from Chapter 3 attempt to compare the performance of these two existing methodologies for estimating health effects from multipollutant sources.
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How Trust in the Food System and in Brands Builds Consumer Confidence in Credence Attributes: A Structural Equation Model2014 July 1900 (has links)
Given the credence nature of food quality and food safety attributes, consumers cannot easily verify whether food is high quality or is safe to eat, thus they rely on abstract systems of regulation and quality signals such as brands to make informed consumption choices. In fact, trust is recognized as a rational strategy that reduces consumers’ uncertainty when purchasing goods with credence attributes. While trust in food is a topical issue in an era of increasingly complex food systems, how trust and more precisely brand trust affects consumers’ perceptions of food is a relatively new research area in food economics.
This thesis aims to answer questions such as what drives trust in the actors within the Canadian food system (i.e. government, farmers, food manufacturers, and food retailers) and in food brands, and the relationship between that trust and consumer confidence in food quality and food safety. Previous studies on institutional and system trust have been carried out primarily in the sociology, marketing and political sciences disciplines, while a few studies in food economics have investigated the influence of institutional trust and reported the degree of public trust in market actors. This study extends previous research on consumer trust in the context of food by developing a conceptual model in which trust in the food system and brand trust are expected to evolve to public confidence in credence attributes and lead to consumer commitment to food brands.
Inspired from a comprehensive synthesis of the literature on consumer trust, the theoretical background suggests that consumer confidence in food attributes is jointly determined by trust in the food system (system-based trust) and brand trust (product-based trust), and it is moderated by consumer characteristics (personal-based trust) – namely: risk, past consumption experience and ethically-motivated behaviour. As well, consumers are assumed to perceive an actor or a brand as trustworthy through the influence of four postulated dimensions of trust: perceived competence, credibility, benevolence and reputation.
A Structural Equation Modelling (SEM) approach is used for the empirical analysis. Data were gathered through an online survey of consumers conducted across Canada in July 2012 focusing on fresh chicken and packaged green salad products. The results show that individually none of the postulated antecedents of trust (i.e. competence, credibility, benevolence and reputation) was a significant driver for trust, especially for packaged salad. Unlike previous research on institutional trust and brand trust that uses a number of separate dimensions to measure trust predominantly in non-food contexts, this thesis finds that trust in the food system and food products could be measured differently by taking into account the interactive effects of perceived competence, credibility, reputation and benevolence on public trust. As such, the findings suggest that Canadian consumers tend to trust brands of chicken and packaged salad when these products are perceived as high quality, are backed by credible information, have a good reputation and, at the same time, enhance consumers’ welfare. In fact, a brand cannot be perceived as high quality and safe to eat (brand competence) without containing transparent information signalling its quality and safety (brand credibility).
Additionally, results reveal some apparent product-specific effects: brand trust matters in fostering consumer confidence in chicken but not for salad. Furthermore, trust in the food system as a whole appears to be more influential in leading to public confidence in credence attributes than trust in food brands in the case of chicken. As such, it appears that trust in actors within the food supply chain is more important than relying on individual products. As well, the analysis shows that while psychographic variables (risk aversion, past consumption experience) and some demographics (e.g. gender, education) moderate the relationship between trust in the food system and brands for chicken, this is not the case for salad.
In terms of marketing implications, the results suggest that while brands are useful signalling mechanisms, trust in these brands is not the main driver for consumer confidence in credence attributes. Furthermore, the much stronger effect of system trust implies that decision-makers would benefit by investing in building trust relationships with the public. Transparent communication and credible assurances about the practices and the intentions within the food system could be a way to gain and maintain public trust and, ultimately, consumer confidence in food quality and food safety.
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A inteligência como capacidade dinâmica : uma relação entre processo de monitoramento de ambiente externo e vantagem competitivaBocaccio, Alessandro Antunes January 2016 (has links)
As organizações estão expostas a uma quantidade e variabilidade cada vez mais crescente de informações. A capacidade de se antecipar às tendências e se adequar ao ambiente passa a ser, além de fonte de vantagem competitiva, fator necessário para a sobrevivência. Nessa realidade, organizações frequentemente apresentam dificuldades de leitura de seu ambiente e adaptação ao meio. Acredita-se na necessidade de desenvolvimento de uma capacidade interna da organização para que o monitoramento do ambiente se estabeleça, bem como análise de oportunidades, planejamento de ações de melhoria e reconfiguração da organização. Este estudo buscou verificar a relação da Inteligência - enquanto processo de monitoramento do ambiente - como uma Capacidades Dinâmica, e de como esta pode contribuir com a geração de vantagem competitiva. Criou-se um modelo de pesquisa, utilizando-se dos modelos de Rios (2010) e Teece (2014), relacionando os conceitos de Inteligência e Capacidade Dinâmicas, e estas com a Vantagem Competitiva. Por meio de um questionário, realizou-se uma Pesquisa Survey, onde coletaram-se respostas de funcionários e/ou sócio de empresas brasileiras, independente de porte ou segmento. Para análise, utilizou-se da Modelagem de Equações Estruturais, e foi possível demonstrar que a Inteligência influencia positivamente nas Capacidades Dinâmicas do sub-grupo Transforming, na Estratégia e na Vantagem Competitiva. Dessa forma o modelo desenvolvido, tendo apresentado boa confiabilidade e aderência, pode também ser validado. / Organizations are exposed to an increasing amount and variability of information. The ability to anticipate trends and adapt to the environment becomes, besides a source of competitive advantage, a necessary factor for survival. In this reality, organizations frequently present difficulties in reading their environment and adapting to them. We believe in the need to develop an internal capacity of the organization for the monitoring of the environment to be established, as well as analysis of opportunities, planning of actions of improvement and reconfiguration of the organization. This study sought to verify the relationship of Intelligence - as a process of monitoring the environment - as a Dynamic Capabilities, and how this can contribute to the generation of competitive advantage. A research model was created, using the models of Rios (2010) and Teece (2014), relating the concepts of Dynamic Intelligence and Capacity, and these with the Competitive Advantage. By means of a questionnaire, a Survey Research was conducted, where responses were collected from employees and / or partners of Brazilian companies, regardless of size or segment. For the analysis, it was used the Modeling of Structural Equations, and it was possible to demonstrate that the Intelligence influences positively in the Dynamic Capacities of the Transforming subgroup, in the Strategy and the Competitive Advantage. In this way the developed model, having presented good reliability and adhesion, can also be validated.
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Analysis of crash and survey data to identify young drivers' distractions in KansasAlfallaj, Ibrahim January 1900 (has links)
Doctor of Philosophy / Department of Civil Engineering / Sunanda Dissanayake / Young drivers are over-represented in crashes when compared to other age group drivers. Distracted driving is one of the major causes of traffic crashes by young drivers. The objective of this study was to assess the hazards of distracted driving among teenage (15–20 year old) and young-adult (21–26 year old) drivers in Kansas. This study used five years of crash data from the Kansas Crash and Analysis Reporting System (KCARS) database from 2011 to 2015. A multinomial logit modeling was used to identify the odds that a driver with a certain type of distraction would be involved in one of the three most common crash types: rear-end, angular, and single-vehicle crashes. Furthermore, ordered logistic modeling was used to analyze the crash data to identify the odds of more severe injuries for teenage and young-adult distracted drivers and their passengers involved in crashes. Survey data was used to develop a structural equation model (SEM) to define the relationship among young drivers’ characteristics (e.g., participants’ socioeconomic and demographic status), attitudes, and behaviors associated with distracted driving and cell phone use while driving.
Preliminary analysis showed that more than 12% of the total young drivers’ crashes were distraction-affected crashes. According to the multinomial logit model results, most distraction types for teenage and young-adult drivers are related to rear-end or angular collisions. However, when distracted by cell phones at night, teenage drivers had a greater probability of being involved in single-vehicle crashes. In addition, when teenage drivers drove with their peers as front-seat passengers and were distracted in/on vehicle or by other electronic devices, they were more likely to be involved in single-vehicle crashes. Young-adult drivers distracted in/on vehicle or by cell phones under different conditions such as while driving old or sport utility vehicles, on curved roads, or at intersections, they were more likely to be involved in single-vehicle or angular crashes. Whereas, when they were inattentive during the weekend, rear-end collisions were the most likely collision type.
According to the results of the ordered logistic model, teenage and young-adult drivers were more likely to be severely injured in cell phone-related crashes. More specifically, female teenage drivers had a greater probability of being severely injured than male teenage drivers when they were distracted by a cell phone, inside the vehicle, or were inattentive. Young-adult drivers that were distracted on road construction work zones by a cell phone or inside the vehicle, they and their passengers had a greater likelihood of sustaining a severe injury.
The SEM results revealed that teenage drivers are more prone than young-adult drivers to drive while distracted and are less likely to support the Kansas laws that ban cell phone use while driving. Also, the model results showed that young drivers who have been involved in crashes or near-crashes during the previous year are more likely to drive while distracted. These results indicate that distractions create threats to the lives of young Kansas drivers, their passengers, and other road users.
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A inteligência como capacidade dinâmica : uma relação entre processo de monitoramento de ambiente externo e vantagem competitivaBocaccio, Alessandro Antunes January 2016 (has links)
As organizações estão expostas a uma quantidade e variabilidade cada vez mais crescente de informações. A capacidade de se antecipar às tendências e se adequar ao ambiente passa a ser, além de fonte de vantagem competitiva, fator necessário para a sobrevivência. Nessa realidade, organizações frequentemente apresentam dificuldades de leitura de seu ambiente e adaptação ao meio. Acredita-se na necessidade de desenvolvimento de uma capacidade interna da organização para que o monitoramento do ambiente se estabeleça, bem como análise de oportunidades, planejamento de ações de melhoria e reconfiguração da organização. Este estudo buscou verificar a relação da Inteligência - enquanto processo de monitoramento do ambiente - como uma Capacidades Dinâmica, e de como esta pode contribuir com a geração de vantagem competitiva. Criou-se um modelo de pesquisa, utilizando-se dos modelos de Rios (2010) e Teece (2014), relacionando os conceitos de Inteligência e Capacidade Dinâmicas, e estas com a Vantagem Competitiva. Por meio de um questionário, realizou-se uma Pesquisa Survey, onde coletaram-se respostas de funcionários e/ou sócio de empresas brasileiras, independente de porte ou segmento. Para análise, utilizou-se da Modelagem de Equações Estruturais, e foi possível demonstrar que a Inteligência influencia positivamente nas Capacidades Dinâmicas do sub-grupo Transforming, na Estratégia e na Vantagem Competitiva. Dessa forma o modelo desenvolvido, tendo apresentado boa confiabilidade e aderência, pode também ser validado. / Organizations are exposed to an increasing amount and variability of information. The ability to anticipate trends and adapt to the environment becomes, besides a source of competitive advantage, a necessary factor for survival. In this reality, organizations frequently present difficulties in reading their environment and adapting to them. We believe in the need to develop an internal capacity of the organization for the monitoring of the environment to be established, as well as analysis of opportunities, planning of actions of improvement and reconfiguration of the organization. This study sought to verify the relationship of Intelligence - as a process of monitoring the environment - as a Dynamic Capabilities, and how this can contribute to the generation of competitive advantage. A research model was created, using the models of Rios (2010) and Teece (2014), relating the concepts of Dynamic Intelligence and Capacity, and these with the Competitive Advantage. By means of a questionnaire, a Survey Research was conducted, where responses were collected from employees and / or partners of Brazilian companies, regardless of size or segment. For the analysis, it was used the Modeling of Structural Equations, and it was possible to demonstrate that the Intelligence influences positively in the Dynamic Capacities of the Transforming subgroup, in the Strategy and the Competitive Advantage. In this way the developed model, having presented good reliability and adhesion, can also be validated.
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International study on factor structure to create a city center vibrant with pedestrians - a field survey of Kyoto, Seoul, Beijing and Florence / 都市中心地区の賑わいの要因構造に関する国際研究-京都、ソウル、北京、フィレンツェの現地調査に基づいてPark, Dongwook 25 March 2013 (has links)
Kyoto University (京都大学) / 0048 / 新制・課程博士 / 博士(工学) / 甲第17536号 / 工博第3695号 / 新制||工||1562(附属図書館) / 30302 / 京都大学大学院工学研究科都市社会工学専攻 / (主査)教授 中川 大, 教授 藤井 聡, 准教授 松中 亮治 / 学位規則第4条第1項該当
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Structural Equation Model of Variables Associated with Family Functioning among a Nationally Representative Sample of Families with a Child with AutismBezner, Stephanie K. 08 1900 (has links)
Previous research indicates that stressors experienced by a family, the perceived level of burden assigned by the family to the stressor, and the utilization of resources predict family functioning. The current study utilized a nationally representative sample of families of children with autistic disorder to determine if previously proposed models of family functioning accurately conceptualized family functioning within a representative sample. Structural equation modeling was utilized to test the double ABCX and the linear ACBX models of family functioning. With slight modifications, the double ABCX model was supported, thus indicating that pileup of stressors, perception of burden, and utilization of resources each have unique predictive ability for family functioning, with perception of burden demonstrating the highest amount of predictive ability. Results, implications, and limitations of the study are discussed.
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Konspirationsteorier, alternativmedicin, vidskepelse och rasism : En studie om trossystem i VoF-undersökningenWallström, Måns January 2022 (has links)
In this study, data from the survey Vetenskap- och Folkbildningsundersökningen 2021 on belief in conspiracy theories, alternative medicine, superstition and racist ideas was analyzed using a multiple causes, multiple indicators structural equation model. It was found that viewing stances on the selected survey questions as a manifestation of these 4 belief systems (belief in conspiracy theories, belief in alternative medicine, superstition, and racism) is supported by the data, and that the belief systems are statistically significantly correlated. Among other results, it was also found that, when controlling for background variables such as size of place of residence, gender, education level and age, persons with a university education believe in conspiracy theories, alternative medicine, superstition and racist ideas to a lesser extent than persons with lower formal education, while sympathizers of the Sweden Democrats hold these beliefs to a greater extent than sympathizers of other parties.
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Sustainable Transportation At The University Of Central Florida: Evaluation Of Ucf Rideshare Program, ZimrideDefrancisco, Joseph Patrick 01 January 2012 (has links)
As the second-largest university in the United States, UCF has experienced the largest enrollment in its history. A more densely populated campus has in turn caused increased traffic congestion. Despite increased parking permit fees and newly constructed parking garages, traveling and parking on campus is unpredictable. In effort to reduce congestion on campus, a rideshare program was implemented in Summer 2010. Several universities across the nation have successfully used carpooling as a viable alternative mode to manage traffic and parking demand. This thesis evaluates the UCF rideshare program, Zimride, using stated- and revealed-preference surveys. Preliminary results indicate most students prefer to commute to campus using their own car and without incentives there is no reason to change mode choice, regardless of associated costs—e.g. decal cost, parking time and frustration. Despite 70% of respondents considering themselves environmentally friendly and over 80% are aware of savings in money and productive by using alternative modes, 70% still use their car to commute to campus. Using Explanatory Factor Analysis (EFA) and Structural Equation Modeling (SEM), the observed variables were organized into three (3) latent variables based on the correlation among them. The SEM results of the revealed-preference survey indicate current travel behavior significantly influences attitudes towards carpooling and demographics have a significant effect on current travel behavior. It was also found that demographics influences attitudes towards carpooling at a non statistically significant level.
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Predicting intent to study abroad among graduate students in higher education and student affairs programs at universities in the southeastern United StatesHolcomb, Hannah Elise 09 August 2019 (has links)
The internationalization of higher education curriculum, including programs in educational leadership, in the United States is increasing, and with the increase in graduate interest in study abroad, this study predicted graduate students pursuing a graduate degree in higher education administration or student affairs (HESA) at institutions in the southeastern United States intent to study abroad short-term. The Theory of Planned Behavior was used to frame the study, which identified the behavioral beliefs (future job prospects), normative beliefs (family expectations), and control beliefs (administrative support) of graduate students that were related to study abroad. Future job prospects, family expectations, and administrative support formed one variable, willingness to pay, which was hypothesized to influence intent to study abroad. Desire and affordability were also hypothesized to influence intent to study abroad. The Theory of Planned Behavior and each variable were assumed to be important to short-term study abroad intent. However, this was an initial study focused on solely graduate students in an education discipline regarding study abroad intent to use the Theory of Planned Behavior and the chosen variables. A survey was emailed to all graduate students in a HESA program at 15 institutions in the southeastern United States. There were 171 students that fully completed the survey. In this study, I found that future job prospects had a positive relationship with willingness to pay. Thus, hypothesis 2 was supported. However, family expectations and administrative support did not have a positive relationship with willingness to pay indicating that hypotheses 3 and 4 were not supported. Regarding intent to study abroad, both desire and affordability positively influenced intent to study abroad with path coefficients of .62 and .24, respectively, while willingness to pay did not indicating that hypotheses 5 and 6 were supported while hypothesis 1 was not supported. The data were analyzed using a structural equation model (SEM) to create a structural model to understand the strength of the relationship of each variable by the resulting path coefficients and variance. Understanding the beliefs and intentions of such students provided implications to establish or improve existing study abroad programs focusing on graduate students.
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