No description available.

Statistical models have been very popular for estimating the performance of highway safety improvement programs which are intended to reduce motor vehicle crashes. The traditional Poisson and Poisson-gamma (negative binomial) models are the most popular probabilistic models used by transportation safety analysts for analyzing traffic crash data. The Poisson-gamma model is usually preferred over traditional Poisson model since crash data usually exhibit over-dispersion. Although the Poisson-gamma model is popular in traffic safety analysis, this model has limitations particularly when crash data are characterized by small sample size and low sample mean values. Also, researchers have found that the Poisson-gamma model has difficulties in handling under-dispersed crash data. The primary objective of this research is to evaluate the performance of the Conway-Maxwell-Poisson (COM-Poisson) model for various situations and to examine its application for analyzing traffic crash datasets exhibiting over- and under-dispersion. This study makes use of various simulated and observed crash datasets for accomplishing the objectives of this research. Using a simulation study, it was found that the COM-Poisson model can handle under-, equi- and over-dispersed datasets with different mean values, although the credible intervals are found to be wider for low sample mean values. The computational burden of its implementation is also not prohibitive. Using intersection crash data collected in Toronto and segment crash data collected in Texas, the results show that COM-Poisson models perform as well as Poisson-gamma models in terms of goodness-of-fit statistics and predictive performance. With the use of crash data collected at railway-highway crossings in South Korea, several COM-Poisson models were estimated and it was found that the COM-Poisson model can handle crash data when the modeling output shows signs of under-dispersion. The results also show that the COM-Poisson model provides better statistical performance than the gamma probability and traditional Poisson models. Furthermore, it was found that the COM-Poisson model has limitations similar to that of the Poisson-gamma model when handling data with low sample mean and small sample size. Despite its limitations for low sample mean values for over-dispersed datasets, the COM-Poisson is still a flexible method for analyzing crash data.

In recent actuarial literature, the bivariate Poisson regression model has been found to be useful for modeling paired count data. However, the basic assumption of marginal equi-dispersion may be quite restrictive in practice. To overcome this limitation, we consider here the recently developed bivariate Conway–Maxwell–Poisson (CMP) distribution. As a distribution that allows data dispersion, the bivariate CMP distribution is a flexible distribution which includes the bivariate Poisson, bivariate Bernoulli and bivariate Geometric distributions all as special cases. We discuss inferential methods for this CMP distribution. An application to automobile insurance data demonstrates its usefulness as an alternative framework to the commonly used bivariate Poisson model. / Thesis / Master of Science (MSc)

Made available in DSpace on 2016-04-27T16:57:32Z (GMT). No. of bitstreams: 1 Dissertacao_FONSECA_Rogerio_F.pdf: 234457 bytes, checksum: dadcc8aefbbc853d08c0ece59abfaad1 (MD5) Previous issue date: 2005-11-28 / Secretaria do Estado e Educação / The subject that is presented in this research is the concept of number, in special the approach that was elaborated by the Mathematician John H. Conway. It is very interesting Conway s concept of number in Mathematics Education, because of two complementary aspects of the definition of number, which are: intensional and extensional. The extensionality is expressed by the application of the concept of number to certain games including the Hackenbush game, which is studied in this presentation. We had the purpose of investigate a new approach to the concept of number, looking for elements that would consequently support the teaching learning process. Our investigation has as presupposition that number is one of the fundamental concepts of Mathematics, that its constitution presents a variety of approaches and that none of them gives the possibility of an answer to the question: What is number? As a subsidy to the investigation we evaluate phylosophical answers aboret the nature and existence of numbers, which provide us clues of the complexity implied in this notion. We also present some researches that study the concept of numbers coming from games, as well as, the implication of such studies to the teaching learning process in Mathematics. / O tema da pesquisa aqui apresentada é o conceito de número, em especial a abordagem elaborada pelo matemático John H. Conway. O interesse, para a Educação Matemática, pela conceituação de Conway está na possibilidade de ela contemplar os dois aspectos complementares da definição do conceito de número, quais sejam: intensional e extensional. A extensionalidade é expressa pela aplicabilidade do conceito de número como certos tipos de jogos, incluindo entre eles o jogo Hackenbush, estudado neste trabalho. Propusemo-nos a investigar uma nova abordagem para o conceito de número, com vistas a buscar nela elementos que favoreçam o ensino e conseqüentemente a aprendizagem. Nossa investigação tem por pressuposto que número é um dos conceitos fundamentais da Matemática e que sua constituição apresenta diversas abordagens, sem que nenhuma delas possibilite responder à questão O que é número? . Como subsídio à investigação, avaliamos algumas respostas de correntes filosóficas sobre a natureza e a existência dos números, as quais nos fornecem pistas das complexidades implícitas nessa noção. Apresentamos também algumas pesquisas que abordam o conceito de números a partir de jogos, assim como a implicação de tal abordagem para o processo de ensino e aprendizagem da Matemática.

The problem under consideration is that of determining a simple and effective invariant of knots. To this end, the Conway polynomial is defined as a generalization of Alexander's original knot polynomial. It is noted, however, that the Conway polynomial is not a complete invariant. If two knots are equivalent, as defined in this investigation, then they receive identical polynomials. Yet, if two knots have identical polynomials, no information about their equivalence may be obtained. To define the Conway polynomial, the Axioms for Computation are given and many examples of their use are included. A major result of this investigation is the proof of topological invariance of these polynomials and the proof that the axioms are sufficient for the calculation of the knot polynomial for any given knot or link.

Thesis (B. Arch.)--Roger Williams University, 2009. / Title from title page screen (viewed on Feb. 11, 2010) Includes bibliographical references. Also available in print.

Submitted by Lucelia Lucena (lucelia.lucena@ufpe.br) on 2015-03-05T18:08:06Z No. of bitstreams: 2 DISSERTAÇÃO Anderson Medeiros de Santana.pdf: 1777781 bytes, checksum: 68b082135f85ee0d2d8758c1fca275f1 (MD5) license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) / Made available in DSpace on 2015-03-05T18:08:06Z (GMT). No. of bitstreams: 2 DISSERTAÇÃO Anderson Medeiros de Santana.pdf: 1777781 bytes, checksum: 68b082135f85ee0d2d8758c1fca275f1 (MD5) license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Previous issue date: 2014-09-08 / Objetivo: O objetivo desse estudo é investigar as relações entre a estrutura de comunicação de uma equipe de software e a arquitetura resultante do desenvolvimento de sistemas sob a perspectiva da Lei de Conway. Método: Foi projetado um quasi-experimento no contexto da indústria de software na qual os resultados de duas equipes de desenvolvimento foram comparados sob um mesmo projeto. Uma das equipes trabalhou uma abordagem ágil baseada em Scrum tendo comunicação frequente. A outra equipe trabalhou sob uma abordagem mais tradicional baseada no estilo de comando-e-controle de gerenciamento hierárquico com comunicação muito limitada entre os membros da equipe. Nós observamos ambas as equipes durante o projeto, entrevistamos os participantes e realizamos um grupo focal para coletar e comparar as impressões dos membros das equipes no final do projeto. Resultados: Foram encontradas enormes diferenças entre o design arquitetural das duas equipes, como previsto. A equipe hierárquica apresentou melhores resultados quanto a eficiência e eficácia do desenvolvimento. A equipe ágil produziu uma solução mais simples, com um design de Sistema mais acoplado do que o apresentado pela equipe hierárquica. Conclusão: Nossas descobertas não apoiam completamente a Lei de Conway, quanto à unidirecionalidade e ao homomorfismo, uma vez que apresentam características mais bidirecionais e polimórficas.

Indiana University-Purdue University Indianapolis (IUPUI) / The two-part model (2PM) is the most widely applied modeling and estimation framework in empirical health economics. By design, the two-part model allows the process governing observation at zero to systematically differ from that which determines non-zero observations. The former is commonly referred to as the extensive margin (EM) and the latter is called the intensive margin (IM). The analytic focus of my dissertation is on the development of a general framework for specifying, estimating and drawing inference regarding causally interpretable (CI) effect parameters in the 2PM context. Our proposed fully parametric 2PM (FP2PM) framework comprises very flexible versions of the EM and IM for both continuous and count-valued outcome models and encompasses all implementations of the 2PM found in the literature. Because our modeling approach is potential outcomes (PO) based, it provides a context for clear definition of targeted counterfactual CI parameters of interest. This PO basis also provides a context for identifying the conditions under which such parameters can be consistently estimated using the observable data (via the appropriately specified data generating process). These conditions also ensure that the estimation results are CI. There is substantial literature on statistical testing for model selection in the 2PM context, yet there has been virtually no attention paid to testing the “one-part” null hypothesis. Within our general modeling and estimation framework, we devise a relatively simple test of that null for both continuous and count-valued outcomes. We illustrate our proposed model, method and testing protocol in the context of estimating price effects on the demand for alcohol.

Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.

Made available in DSpace on 2016-04-27T16:57:02Z (GMT). No. of bitstreams: 1 Rogerio Ferreira da Fonseca.pdf: 1033862 bytes, checksum: 7874e284aff29ac820ecbd35113c89ae (MD5) Previous issue date: 2010-11-26 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / This research is theoretical and has the goal of studying the concept of the real number. Epistemological issues are discussed surrounding the concept of number in general, and in particular the concept of real numbers. The discussions are based on the concept of complementarity as regards the analysis of cognitive and epistemological aspects of mathematical concepts. The focus of the research is to investigate a new proposal for the concept of numbers presented by the British mathematician John Horton Conway of Princeton University, which allows one to uniquely answer the question, What is a number? , which has long mobilized Mathematics philosophers and epistemologists. In addition, for this theory, a class of games is presented as a model for interpretation or application of the theory, thereby conceptualizing number as a game. Moreover, the game has assisted in learning Mathematics. We can conclude with this research that Conway s theory, in a complementary manner, can add new elements to the classical approaches to the concept of number, can indicate some of its weaknesses, and can highlight the importance of epistemological questioning in the evolution of mathematical knowledge. Another result of this research is to indicate the fertility of the concept of number that opens new frontiers for Mathematics. It is our opinion that Mathematics Education needs to be and should be close to advances in Mathematics / Esta pesquisa é de cunho teórico e tem por alvo o estudo do conceito de número real. Nela são discutidas questões de ordem epistemológicas que cercam o conceito de número, em geral, e em particular o conceito de número real. As discussões estão fundamentadas no conceito de complementaridade no que concerne à análise de aspectos cognitivos e epistemológicos de conceitos matemáticos. O foco da pesquisa é investigar uma nova proposta de conceituação de número apresentada pelo matemático inglês John Horton Conway, da Universidade de Princeton, a qual possibilita responder, de forma única, à questão: o que é número?, indagação que mobilizou filósofos e epistemólogos da Matemática por muito tempo. Além disso, para esta teoria uma classe de jogos se apresenta como um modelo de interpretação ou aplicação da teoria, conceituando então número como um jogo. Aliás, o jogo tem sido um auxiliar na aprendizagem da Matemática. Podemos inferir com esta pesquisa que a teoria de Conway de forma complementar pode acrescentar novos elementos às abordagens clássicas da conceituação de número, apontar algumas de suas fragilidades e destacar a importância dos questionamentos epistemológicos para a evolução do conhecimento matemático. Outro resultado desta pesquisa é indicar a fertilidade do conceito de número que ainda abre novas fronteiras para a Matemática. É nosso julgamento que a Educação Matemática precisa e deve estar próxima dos avanços da Matemática