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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.
21

A Bayesian approach to predict the number of soccer goals : Modeling with Bayesian Negative Binomial regression

Bäcklund, JOakim, Nils, Johdet January 2018 (has links)
This thesis focuses on a well-known topic in sports betting, predicting the number of goals in soccer games.The data set used comes from the top English soccer league: Premier League, and consists of games played in the seasons 2015/16 to 2017/18.This thesis approaches the prediction with the auxiliary support of the odds from the betting exchange Betfair. The purpose is to find a model that can create an accurate goal distribution. %The other purpose is to investigate whether Negative binomial distribution regressionThe methods used are Bayesian Negative Binomial regression and Bayesian Poisson regression. The results conclude that the Poisson regression is the better model because of the presence of underdispersion.We argue that the methods can be used to compare different sportsbooks accuracies, and may help creating better models.
22

Modelos para dados de contagem com aplicações / Models for count data with applications

Mendes, Clarice Camargo 05 March 2007 (has links)
Orientador: Hildete Prisco Pinheiro / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Matematica, Estatistica e Computação Cientifica / Made available in DSpace on 2018-08-08T17:00:10Z (GMT). No. of bitstreams: 1 Mendes_ClariceCamargo_M.pdf: 1127292 bytes, checksum: f015352011300a41bb50c17c81a49bb1 (MD5) Previous issue date: 2007 / Resumo: Ao lidarmos com dados de contagem, uma abordagem possível é estimar um Modelo Linear Generalizado com distribuição de Poisson. Freqüentemente nestes modelos costuma surgir o problema da superdispersão, um fenômeno que aparece quando estamos diante de uma variabilidade dos dados maior do que a média. Temos basicamente três soluções para este problema: abordagem bayesiana, assumindo que o parâmetro do modelo possui uma distribuição de probabilidade; estimação por Quase-verossimilhança, incluindo um fator de dispersão diferente da unidade ou uma função de variância diversa e, finalmente, o emprego de modelos mistos, com a separação de efeitos fixos e aleatórios. Outra ocorrência comum para dados de contagem é encontrarmos amostras que apresentem um número excessivo de zeros. Detectamos a presença da superdispersão, mas agora ela é devida à ocorrência de mais valores zero na amostra do que seria esperado para dados que seguissem a distribuição de Poisson. Para este caso Lambert (1982) apresenta a chamada regressão de Poisson inflacionada de zeros (ZIP - Zero lnflated Poisson). Através de uma aplicação a dados reais, em estudo referente à alimentação de rãs da espécie Adenomera, identificamos os melhores modelos para explicar a quantidade de comida ingerida em função dos efeitos de sexo e da estação do ano. Utilizamos técnicas de diagnóstico para avaliar o impacto que uma determinada observação exerce na estimativa dos parâmetros. / Abstract: When one deals with count data, a possible approach is to fit a generalized linear model with Poisson distribution. Usually it may occur the problem of superdispersion, when the variability of the data is greater then the mean. There are three basic solutions to this problem: the Bayesian approach, when we assume that the parameter of the mo deI has a distribution of probability; the Quasilikelihood estimation, including a non-unitary dispersion parameter or a different variance function and, finally, the mixed models. Another possible occurrence to count data is the presence of samples with an excess of zeros. We detect the presence of the superdispersion, but now it is due to more zero counts than expected from the Poisson distribution. For this case, Lambert (1982) presents the Zero Infiated Poisson (ZIP) mode. As an application to real data, in the study of frogs' nourishment from the species Adenomera, we identify the best models to explain the quantity of swallowed food related to sex and season effects. We employ techniques of diagnosis to verify the impact of a specific observation in the parameter estimations / Mestrado / Bioestatistica / Mestre em Estatística
23

Faktory ovlivňující regionální diferenciaci úmrtnosti v České republice / Determinants of Regional Differentiation of Mortality in the Czech Republic

Pachlová, Tereza January 2014 (has links)
Determinants of Regional Differentiation of Mortality in the Czech Republic Abstract There are considerable differences in socioeconomic and sociodemographic factors influencing mortality on the individual and also on the aggregate levels. These differences were observed and explained in many countries of the world. The objective of this thesis is to find and evaluate the most significant external factors which influence actual regional differentiation of mortality in districts of the Czech Republic. The objective was achieved by means of the demographic and statistical analysis methods. First, there was a comparison of mortality rates calculated for each of the socioeconomic clusters. It was found out that higher mortality rates appeared among men and women living in the districts with unfavourable external conditions. Using the Poisson log-linear model, the most important factors influencing differences in mortality rates in districts of the Czech Republic were identified. These factors are: share of the unemployed, share of the divorced, share of university-educated people and the number of physicans in hospitals per 1000 inhabitants. Share of the unemployed seems to be the most significant factor. There is a correlation between this factor and the total mortality rate as well as the leading causes of...
24

Bayesian Hidden Markov Model in Multiple Testing on Dependent Count Data

Su, Weizhe January 2020 (has links)
No description available.
25

Experimental design issues in impaired reproduction applications

Chiacchierini, Lisa M. 06 June 2008 (has links)
Within the realms of biological and medical research, toxicity studies which measure impaired reproduction are becoming more and more common, yet methods for efficiently designing experiments for these studies have received little attention. In this research, response surface design criteria are applied to four models for impaired reproduction data. The important role of control observations in impairment studies is discussed, and for one model, a normal error linear model, a design criterion is introduced for allocating a portion of the sample to the control. Special attention is focused on issues surrounding optimal design of experiments for two of the models, a Poisson exponential model and a Poisson linear model. As most of the optimal designs for these models are obtained via numerical methods rather than directly from criteria, equivalence theory is used to prove analytically that the numerically obtained designs are truly optimal. A further complication associated with designing experiments for Poisson regression is the need to know parameter values in order to implement the optimal designs. Thus, two stage design of experiments is investigated as one solution to this problem. Finally, since researchers frequently do not know the appropriate model for their data a priori, the optimal designs for these two different models are compared, and designs which are robust to model misspecification are highlighted. / Ph. D.
26

Behavioral specifications of network autocorrelation in migration modeling: an analysis of migration flows by spatial filtering

Chun, Yongwan 14 September 2007 (has links)
No description available.
27

Safety Benchmarking of Industrial Construction Projects Based on Zero Accidents Techniques

Rogers, Jennifer Kathleen 26 June 2012 (has links)
Safety is a continually significant issue in the construction industry. The Occupation Safety and Health Administration as well as individual construction companies are constantly working on verifying that their selected safety plans have a positive effect on reduction of workplace injuries. Worker safety is a large concern for both the workers and employers in construction and the government also attempts to impose effective regulations concerning minimum safety requirements. There are many different methods for creating and implementing a safety plan, most notably the Construction Industry Institute's (CII) Zero Accidents Techniques (ZAT). This study will attempt to identify a relationship between the level of ZAT implementation and safety performance on industrial construction projects. This research also proposes that focusing efforts on certain ZAT elements over others will show different safety performance results. There are three findings in this study that can be used to assist safety professionals in designing efficient construction safety plans. The first is a significant log-log relationship that is identified between the DEA efficiency scores and Recordable Incident Rate (RIR). There is also a significant difference in safety performance found between the Light Industrial and Heavy Industrial sectors. Lastly, regression is used to show that the pre-construction and worker selection ZAT components can predict a better safety performance. / Master of Science
28

Modeling Driving Risk Using Naturalistic Driving Study Data

Fang, Youjia 21 October 2014 (has links)
Motor vehicle crashes are one of the leading causes of death in the United States. Traffic safety research targets at understanding the cause of crash, preventing the crash, and mitigating crash severity. This dissertation focuses on the driver-related traffic safety issues, in particular, on developing and implementing contemporary statistical modeling techniques on driving risk research on Naturalistic Driving Study data. The dissertation includes 5 chapters. In Chapter 1, I introduced the backgrounds of traffic safety research and naturalistic driving study. In Chapter 2, the state-of-practice statistical methods were implemented on individual driver risk assessment using NDS data. The study showed that critical-incident events and driver demographic characteristics can serve as good predictors for identifying risky drivers. In Chapter 3, I developed and evaluated a novel Bayesian random exposure method for Poisson regression models to account for situations where the exposure information needs to be estimated. Simulation studies and real data analysis on Cellphone Pilot Analysis study data showed that, random exposure models have significantly better model fitting performances and higher parameter coverage probabilities as compared to traditional fixed exposure models. The advantage is more apparent when the values of Poisson regression coefficients are large. In Chapter 4, I performed comprehensive simulation-based performance analyses to investigate the type-I error, power and coverage probabilities on summary effect size in classical meta-analysis models. The results shed some light for reference on the prospective and retrospective performance analysis in meta-analysis research. In Chapter 5, I implemented classical- and Bayesian-approach multi-group hierarchical models on 100-Car data. Simulation-based retrospective performance analyses were used to investigate the powers and parameter coverage probabilities among different hierarchical models. The results showed that under fixed-effects model context, complex secondary tasks are associated with higher driving risk. / Ph. D.
29

Understanding the relationship between land use/land cover and malaria in Nepal

Bhattarai, Shreejana 02 July 2018 (has links)
Malaria is one of the leading causes of mortality and morbidity globally. Land use/land cover (LULC) change have been found to affect the transmission and distribution of malaria in other regions, but no study has attempted to examine such relationships in Nepal. Therefore, this study was conducted in Nepal to assess LULC change between 2000 and 2010, to study the spatial and temporal trend of malaria incidence rate (MIR) between 1999 and 2015, and to understand the relationship between LULC and malaria. The land cover types used for this study are forest, water bodies, agriculture, grassland, shrubland, barren areas, built-up areas and paddy areas. Change detection techniques were used to study LULC change. The temporal trend of MIR in 58 districts, and the relationship between MIR and LULC were evaluated using Poisson and negative binomial regression. Forest, water bodies, snow cover, and built-up area increased in Nepal by 28.5%, 2.96%, 55.12% and 21.19% respectively while the rest of the LULC variables decreased. MIR decreased significantly in 21 districts; however, four districts namely Pyuthan, Kaski, Rupandehi and Siraha had a significantly increasing trend of MIR. During 2001, 2002, and 2003, MIR was positively related to water bodies and paddy areas. Similarly, MIR of 2010 was negatively related to grassland. However, there was no relationship between LULC and MIR in 2000, 2011, 2012 and 2013. It may be because MIR is decreasing significantly in the country and thus the influence of LULC change is also decreasing. / MS
30

Modelování četností pojistných událostí / Claims count modeling in insurance

Škoda, Štěpán January 2013 (has links)
1 Abstract: The present work investigates techniques of insurence ratemaking accor- ding to the claims counts of policyholders on the basis of information contained in policies. At the beginning, we provide a closer examination of the theory of genera- lized linear models, which have wide range of applications in the field of actuarial modeling. The second chapter presents the basic Poisson regression model as well as some particular verification methods. Specifically, deviance and Wald test could be found here and furthermore also important results for residuals. The third chapter contains information on alternative approaches to modeling the claim frequencies and at the end the GEE method, that can be applied in case of panel data, is de- scribed. The numerical study based on real insurace data in last part of this diploma thesis illustrate's previously described techniques which were obtained with the help of statistical software SAS.

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