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The study of social network dynamics has become an increasingly important component of many disciplines in the social sciences. In the past decade, statistical models and methods have been proposed which permit researchers to draw statistical inference on these dynamics. This thesis builds on one such family of models, the stochastic actor oriented model (SAOM) proposed by Snijders [2001]. Goodness of fit for SAOMs is an area that is only just beginning to be filled in with appropriate methods. This thesis proposes a Mahalanobis distance based, Monte Carlo goodness of fit test that can depend on arbitrary features of the observed network data and covariates. As remediating poor fit can be a difficult process, a modified model distance (MMD) estimator is devised that can help researchers to choose among a set of model elaborations. In practice, panel data is typically used to draw SAOM-based inference. This thesis also proposes a score-type test for time heterogeneity between the waves in the panel that is computationally cheap and fits into a convenient, forward model selecting workflow. Next, this thesis proposes a rigorous method for aggregating so-called relational event data (e.g. emails and phone calls) by extending the SAOM family to a family of hidden Markov models that suppose a latent social network is driving the observed relational events. Finally, this thesis proposes a measurement model for SAOMs inspired by error-in-variables (EiV) models employed in an array of disciplines. Like the relational event aggregation model, the measurement model is a hidden Markov model extension to the SAOM family. These models allow the researcher to specify the form of the mesurement error and buffer against potential attenuating biases and other problems that can arise if the errors are ignored.

Fungal infection and mycotoxin contamination in agricultural products are a serious food safety issue. The detection of fungal infection and mycotoxin contamination in food products should be in a rapid way. A Near-infrared (NIR) hyperspectral imaging system was used to detect fungal infection in 2013 crop year canola, wheat, and barley at different periods after inoculation and different concentration levels of ochratoxin A in wheat and barley. Artificially fungal infected (Fungi: Aspergillus glaucus, Penicillium spp.) kernels of canola, wheat and barley, were subjected to single kernel imaging after 2, 4, 6, 8, and 10 weeks post inoculation in the NIR region from 1000 to 1600 nm at 61 evenly distributed wavelengths at 10 nm intervals. The acquired image data were in the three-dimensional hypercube forms, and these were transformed into two-dimensional data. The two-dimensional data were subjected to principal component analysis to identify significant wavelengths based on the highest principal component factor loadings. Wavelengths 1100, 1130, 1250, and 1300 nm were identified as significant for detection of fungal infection in canola kernels, wavelengths 1280, 1300, and 1350 nm were identified as significant for detection of fungal infection in wheat kernels, and wavelengths 1260, 1310, and 1360 nm were identified as significant for detection of fungal infection in barley kernels. The linear, quadratic and Mahalanobis statistical discriminant classifiers differentiated healthy canola kernels with > 95% and fungal infected canola kernels with > 90% classification accuracy. All the three classifiers discriminated healthy wheat and barley kernels with > 90% and fungal infected wheat and barley kernels with > 80% classification accuracy. The wavelengths 1300, 1350, and 1480 nm were identified as significant for detection of ochratoxin A contaminated wheat kernels, and wavelengths 1310, 1360, 1480 nm were identified as significant for detection of ochratoxin A contaminated barley kernels. All the three statistical classifiers differentiated healthy wheat and barley kernels and ochratoxin A contaminated wheat and barley kernels with a classification accuracy of 100%. The classifiers were able to discriminate between different durations of fungal infections in canola, wheat, and barley kernels with classification accuracy of more than 80% at initial periods (2 weeks) of fungal infection and 100% at the later periods of fungal infection. Different concentration levels of ochratoxin A contamination in wheat and barley kernels were discriminated with a classification accuracy of > 98% at ochratoxin A concentration level of ≤ 72 ppb in wheat kernels and ≤ 140 ppb in barley kernels and with 100% classification accuracy at higher concentration levels. / May 2016

Introdução: Diferentes pesquisas apontam que os estressores acadêmicos podem impactar na saúde dos discentes de enfermagem. Por outro lado, sabe-se que alguns indivíduos são capazes de se adaptar a situações de adversidade (resiliência), apresentando melhores condições de saúde. No entanto, pouco se sabe se tais alterações estão relacionadas ao ingresso no curso superior, pois poucas pesquisas analisam tais alterações longitudinalmente, bem como as relações simultâneas entre os fenômenos de saúde e o papel da resiliência na melhoria da saúde dos discentes. Objetivos: identificar se ocorrem alterações na saúde, nos níveis de resiliência e na qualidade de vida de discentes após um ano do ingresso no curso de graduação em enfermagem; e analisar como se dão as relações simultâneas de causalidade entre estresse psicoemocional, sintomas depressivos, qualidade do sono e resiliência na explicação da qualidade de vida dos discentes um ano após o ingresso no curso. Método: Essa pesquisa organiza-se em duas etapas de abordagem quantitativa: metodológica (Calibração) e longitudinal. Na Fase 1, coletaram-se os dados com alunos do 2o, 3o e 4o anos (respectivamente 4o,6o e 8o semestres) de uma universidade estadual de São Paulo. Na etapa seguinte, a coleta ocorreu com os alunos do 1o ano (1o e 2o semestres de 2016) no início das aulas e ao final do ano letivo com os instrumentos já calibrados em duas universidades de São Paulo, uma estadual e outra federal. Nessas etapas, aplicaram-se os seguintes instrumentos: Formulário para caracterização sociodemográfica e acadêmica; Instrumento para Avaliação do Estresse em Discentes de Enfermagem, Center for Epidemiologic Studies Depression Scale, Índice de Qualidade de Sono de Pittsburgh; Escala de Resiliência de Wagnild & Young; e o Instrumento de Avaliação de Qualidade de Vida. Utilizou-se a análise fatorial confirmatória para a calibração dos instrumentos e o teste ANOVA para modelos mistos para analisar as alterações de saúde, resiliência e qualidade de vida ao longo do ano letivo. A Modelagem de Equações Estruturais foi utilizada para compreender as relações de dependência entre as variáveis. Resultados: A estrutura fatorial e a consistência interna foram satisfatórias para explicar os fenômenos. 110 discentes participaram da calibração dos instrumentos e 117 compuseram a fase longitudinal em março e 100 em dezembro de 2016. Verificou-se aumento significativo do estresse psicoemocional em todos os domínios do instrumento; redução da duração e da qualidade subjetiva do sono; e aumento do estresse psicoemocional geral e dos sintomas depressivos. O modelo hipotetizado final presentou boa qualidade de ajuste e de resíduos. O estresse psicoemocional reduziu a qualidade do sono e aumentou a intensidade dos sintomas depressivos, os quais diminuíram a qualidade de vida direta e indiretamente (através do estresse). A resiliência reduziu os níveis de estresse e sintomas depressivos e melhorou a qualidade do sono. Conclusão: O ambiente acadêmico de enfermagem apresenta potencial para doenças, com impacto à qualidade de vida. O estresse psicoemocional é o preditor dos fenômenos analisados e a resiliência um fator protetor contra o estresse. Sugere-se que as instituições repensem seus elementos curriculares, promovam a resiliência e criem espaços de promoção à saúde dos alunos. / Introduction: Several investigations highlight that academic stressors may impact on the health status of undergraduate nursing students. On other hand, the previous literature confirms that few individuals are able of adapting to adverse situations and, so, present a better health condition. However, it is not clear if the changes in health status are related to the nursing degree program once: few studies have longitudinally assessed health status changes; the simultaneous relations among health phenomena; and the potential role of resilience on nursing students health. Objectives: to identity if the health status, resilience and quality of life of nursing degree students change after the first academic-year; and to assess how the simultaneous relations of causality among psycho-emotional stress, depressive symptoms, sleep quality and resilience are arranged to explain the quality of life of nursing degree students after the first academic-year. Method: this research is organized in two phases, both of quantitative approach: Phase 1-methodologic (tools calibration) assessment; and Phase 2- longitudinal study. In the Phase 1, data were gathered from students enrolled in the 2nd, 3rd and 4th academic years (respectively 4th,6th, and 8th semesters) of a state university of Sao Paulo. In the next phase, we gathered the data from 1st year (1st and 2nd semesters of 2016) students at the starting of classes and one year after the first data collection with the calibrated instruments in two universities of Sao Paulo- one state and other federal. In these phases, we applied the following instruments: demographic and academic form; Instrument for stress evaluation in nursing students, Center for Epidemiologic Studies Depression Scale, Pittsburgh Sleep Quality Index; Connor-Davidson Resilience Scale; and the Instrument for Quality of Life Assessment. We used the confirmatory factor analysis to calibrate the instruments and the ANOVA for mixed models to assess the changes in health status across the first academic year. The Structural Equation Modelling was applied to evaluate the dependency relations among the variables. Results: the factorial structure and the internal consistency were satisfactory to explain the phenomena. 110 students attended the instruments calibration phase. In the longitudinal phase, 117 students were included in March and 100 in December 2016. We found a significant increase of psycho-emotional stress in all instruments domains; a decrease of duration and subjective quality of sleep; and an increase of general psychoemotional stress and depressive symptoms. The final hypothesized model showed good adjustment for quality and residues indexes. The psycho-emotional stress reduced the sleep quality and increased the depressive symptoms, which decreased the quality of life directly and indirectly (Through the stress). Resilience relieved the stress levels and the depressive symptoms and improved the sleep quality. Conclusion: the nursing academic environment has potential for illnesses, with impact on quality of life. The psycho-emotional stress is predictor of the assessed phenomenon and resilience is a protective factor against stress. We suggest that the teaching institutions rethink the curricular elements, promote the resilience and create spaces for students health promotion.

The demand on transportation infrastructure is dramatically increasing due to population growth causing the transportation systems to be pushed to their limits. With the projected population growth, not only for the U.S. but especially for the higher education field, university campuses are of great importance for transportation engineers. Urban univeristy campuses are considered major trip generators and with the population forecast many challenges are bound to arise. The implementation of an improved transit system provides a lower-cost solution to the continuously increasing congestion problems in university campus road networks and surrounding areas. This paper presents a methodology focused on the development of a hybrid system concentrated in three main aspects of transit functionality : access to bus stop location, reasonable travel time and low cost. Two methods for bus stop locations assessment are presented for two levels of analysis : microscopic and mesoscopic. The resulting travel time from the improved bus stop locations is analyzed and compared to the initial conditions by using a microsimulation platform. The development of a mathematical model targets the overall system's cost minimization, including user and operator cost, while maximizing the service coverage. The results demonstrate the benefits of the bus stop assessment by the two applied methods, as well as, the benefits of the route and headway selection based on the mathematical model. Moreover, the results indicate that the generation of routes using travel time as the impedance factor generates the optimal possible routes to obtain the minimum system's overall cost. / by Alicia Benazir Portal Palomo. / Thesis (M.S.C.S.)--Florida Atlantic University, 2012. / Includes bibliography. / Electronic reproduction. Boca Raton, Fla., 2012. Mode of access: World Wide Web.

No settlement remains at Early Dynastic Memphis, the first ‘capital’ of the newly emerging Egyptian state, have yet been located. This study draws together exclusive evidence from three well-known non-elite Memphite cemeteries Saqqara-Serapeum, Turah and the recently excavated site of Helwan (all dating from 3200 to 2700 BC) to explore the society of this early urban centre through its funerary remains. The study engages in statistical analyses of cemetery data comparing grave parameters such as volume, quantity of grave goods, their materials and pottery vessel types, but also architecture, body protection, skeletal sex and the age of the deceased across sites. The application of statistical hypothesis testing techniques forms a methodological cornerstone highlighting some pitfalls of mortuary analyses rooted in Processual theoretical frameworks. As a result, a nuanced funerary culture with a significant degree of mortuary variability was revealed at each of the sites investigated. Non-elite funerary provision at Memphis was influenced by a complex web of factors such as economic potential, relationships to local elites, communal and personal identities, choice, and practicality. While mortuary differentiation by sex could not be proven statistically, evidence emerged for significant age differentiation in the funerary provision. The four communities investigated are distinct and each represent a different population within the Memphite region ranging from a main necropolis (Helwan) to a cemetery of a secondary or tertiary local centre (Turah). The smallscale regionality observed at Memphis should serve as a springboard for future research on Early Dynastic Egypt. Finally, the study has highlighted the research potential of statistical analyses to extract vital information from old data, alongside the importance of hypothesis testing in the evaluation of such analyses.

Sit, Tony. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2008. / Includes bibliographical references (leaves 49-51). / Abstracts in English and Chinese. / Acknowledgement --- p.v / Chapter 1 --- Introduction --- p.1 / Chapter 2 --- Background --- p.4 / Chapter 2.1 --- Approaches to Risk Measurement --- p.4 / Chapter 2.2 --- Is VaR a “Good´ح Risk Measure? --- p.9 / Chapter 2.3 --- "Efficient Capital Market, Random Walk and Unit Root" --- p.11 / Chapter 3 --- Historical VaR and Limitations --- p.17 / Chapter 3.1 --- Regression Analysis --- p.18 / Chapter 3.2 --- A Possible Artifact --- p.19 / Chapter 4 --- "Parametric VaR with GARCH(1,1)" --- p.27 / Chapter 4.1 --- "GARCH(1,1), a Conditional Heteroscedastic Model" --- p.27 / Chapter 4.2 --- RiskMctrics VaR --- p.29 / Chapter 5 --- VaR with Regression Quantiles --- p.34 / Chapter 5.1 --- Quantilc Regression --- p.35 / Chapter 5.1.1 --- "Quantiles, Ranks and Optimisation" --- p.35 / Chapter 5.2 --- CAViaR --- p.39 / Chapter 5.2.1 --- The model --- p.39 / Chapter 5.2.2 --- Empirical Studies --- p.42 / Chapter 6 --- Conclusion and Future Research --- p.46 / Bibliography --- p.48

published_or_final_version / Electrical and Electronic Engineering / Master / Master of Philosophy

In this study, regularly measured long-term leachate data from Bursa Municipal Solid Waste Landfill (MSWL) were analyzed using conventional statistical, time series and factor analyses to investigate in detail the temporal variability of leachate quality and quantity, trend, randomness, seasonality and the auto- and cross- correlations of leachate pollutants. Evaluating the results of data analyses, leachate management recommendations, including sampling strategies in monitoring programs and treatment alternatives for old and fresh leachates, were developed. Statistically analyzed leachate parameters included BOD, COD, pH, SS, electrical conductivity, total CrO4, Cr6+, Fe, Cu, Zn, Pb, Cd, CN-, Cl, F, total P, NH4-N, total N, SO4, S2-, total alkalinity and leachate flow rate. Results indicated that the majority of pollutant concentrations varied in large ranges. Leachate parameters usually showed non-normal distributions and high variability in the closed T Valley compared to the open Main Valley. The majority of leachate parameters was autocorrelated and had statistically significant correlations amongst themselves. Factor analysis showed that different inter-relationships were present between leachate parameters for closed and open valleys. The sampling frequency and the number of leachate parameters need to be measured were determined to be higher for open landfills than for closed landfills. It was recommended that leachates, having high organic strength, in open landfill be treated using biological and physical/chemical processes. However, after the closure of the landfill, physical/chemical processes were recommended for leachate treatment, as it gradually completes transition from fresh to old leachate.

Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniv., 2007. / Härtill 4 uppsatser.