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Grandin, Lori Cristina. "Aplicações de modelos logisticos regressivos em biologia molecular." [s.n.], 2006. http://repositorio.unicamp.br/jspui/handle/REPOSIP/307187.
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Orientador: Hildete Prisco Pinheiro<br>Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Matematica, Estatistica e Computação Cientifica<br>Made available in DSpace on 2018-08-06T00:58:27Z (GMT). No. of bitstreams: 1
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Previous issue date: 2006<br>Resumo: O avanço do sequenciamento dos genes tem incentivado o desenvolvimento de novas técnicas estatísticas para analisar dados genéticos. Nesse trabalho, os modelos logísticos regressivos, introduzidos por Bonney (1986), são apresentados primeiramente no contexto de análise de dados de família e posteriormente esses modelos são utilizados para analisar freqüências de códons em seqüências de DNA mitocondrial. Considerar independência entre os nucleotídeos no códon pode ser uma suposição muito forte, ou seja, biologicamente irreal. Por isso, várias estruturas de dependência são apresentadas para analisar as freqüências dos códons. Por exemplo, uma estrutura markoviana de primeira ordem pode ser adequada para explicar a dependência das bases no códon. A função de log-verossimilhança é avaliada e várias comparações são feitas para analisar qual o modelo mais parcimonioso. Aplicações desses modelos são feitas utilizando-se dados reais de seqüências do gene NADH4 do genoma mitocondrial humano<br>Abstract: The advance of gene sequencing has stimulated the development of new statistical techniques to analyze genetic data. In this work the logistic regressive models, introduced by Bonney (1986), are presented first in the context of analysis of familial data and then they are used to analyze codon frequencies in mitochondrial DNA sequences. The assumption of independence among nucleotide frequencies in a codon can be a very strong one, or biologically unreal. In view of this, several structures of dependence are presented to analyze the codon frequencies. For example, a first order Markovian structure can be appropriate to explain the dependence of the base frequencies in the codon. The log-likelihood function is evaluated and several comparisons are made to analyze which is the most parcimonious model. Applications of these models are made using real data of NADH4 gene sequences of the human mitochondrial genome<br>Mestrado<br>Bioestatistica<br>Mestre em Estatística
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Porrelli, Raul Neder. "Modelos logisticos quadraticos com maxima verossimilhança penalizada para previsão de estrutura secundaria de proteinas." [s.n.], 1995. http://repositorio.unicamp.br/jspui/handle/REPOSIP/259808.
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Orientador: Renato M. E. Sabbatini<br>Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Eletrica<br>Made available in DSpace on 2018-07-21T01:42:31Z (GMT). No. of bitstreams: 1
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Previous issue date: 1995<br>Resumo: Apesar do grande número de algoritmos existentes para a previsão de estrutura secundária de proteínas, determinadas técnicas estatísticas ainda não haviam sido exploradas. Utilizamos a metodologia de funções discriminantes logísticas na tentativa de ultrapassar a acurácia obtida por métodos que usaram redes neurais e teoria da informação. O número de parâmetros foi limitado explorando-se a natureza periódica das alfa-hélices e placas pregueadas beta. Uma grande variedade de modelos foi pesquisada, usando abordagem semi-paramétrica (máxima verossimilhança com penalização) combinada com seleção gradual de parâmetros. Mostramos que os modelos mais bem sucedidos tem ao redor de 800 parâmetros "efetivos" para o conjunto de dados utilizado. Os 340 parâmetros lineares e parte dos 800 parâmetros quadráticos puderam ser interpretados do ponto de vista físico-químico, contrastando com outros métodos da literatura. Após otimização e validação _cruzada, a acurácia foi de 65.9% para três estados estruturais, o que representa um resultado ligeiramente superior aos dos algoritmos já publicados. A maior acurácia de previsão está concentrada numa porção dos resíduos e a confiança da previsão pode ser facilmente calculada. Exploramos a possibilidade de usar estes resíduos, previstos com alta confiabilidade, para prever a estrutura completa da proteína, assim como muitos outros artifícios para aumentar a eficiência do método, com resultados limitados. Embora tenhamos obtido apenas uma modesta melhora da acurácia, a maneira como implementamos o modelo sugere que utilizamos toda a informação estrutural contida em segmentos de até 17 aminoácidos, no nível de complexidade que a quantidade de dados permite<br>Mestrado<br>Mestre em Engenharia Elétrica
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Maximiano, Nilcilene. "Perfil materno-infantil de nascimentos por parto duplo em uma amostra de puérperas no município do Rio de Janeiro, 1999-2001." reponame:Repositório Institucional da FIOCRUZ, 2002. https://www.arca.fiocruz.br/handle/icict/4905.
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Previous issue date: 2002<br>Este estudo teve a finalidade de investigar o parto duplo em uma amostra de puérperas que estiveram hospitalizadas em maternidades do Município do Rio de Janeiro (MRJ), de junho de 1999 a março de 2001. Uma amostra de mães de parto único e seus bebês foi selecionada como grupo de comparação. Aplicou-se análise descritiva através de comparações de proporções (teste x2 ) e médias (teste t) e análise univariada e multivariada por meio de regressão logística, com o objetivo de determinar, dentre as características maternas e dos bebês incluídos no estudo, aquelas mais fortemente associadas com a gemelaridade em cada grupo de comparação. Foram estimadas as associações entre as variáveis pela razão de produtos cruzados - Odds Ratio (OR) e respectivos intervalos de confiança. Os resultados mostraram um índice de gemelaridade de 1,08 por cento e que 58,2 por cento dos gêmeos apresentaram baixo peso ao nascer. Na análise descritiva dos bebês segundo a ordem de nascimento encontrou-se diferenças significantes (p menor ou igual a 0,05) em relação ao tipo de apresentação e índices de Apgar no primeiro e quinto minutos. Analisando-se os gêmeos segundo o sexo do par constatou-se que uma maior proporção de bebês de sexo diferente (menino-menina) nasceu de parto cirúrgico (p = 0,005) e o grupo de meninas necessitou mais freqüentemente de internação em berçário ou UI/UTI (p = 0,008). A análise multivariada por regressão logística evidenciou que a variável mais importante na comparação entre gêmeos e únicos foi o peso ao nascer (OR = 12,78; IC = 6,31-25,90), após controlar sua contribuição pela idade gestacional e outras variáveis. A comparação das características das puérperas por meio de regressão logística múltipla mostrou que as mães de parto gemelar residem mais freqüentemente fora do MRJ (OR = 3,65; IC = 2,06-6,45) quando comparadas com as de parto único. O fato da puérpera poder ficar com acompanhante apresentou-se significativamente correlacionado a gemelaridade, assim como o número inadequado de consultas pré-natais e trabalho remunerado. Os achados deste estudo sugerem que as gestantes de parto duplo que utilizam as maternidades do MRJ não estão sendo ainda identificadas como de risco pela rede assistencial de saúde, com vistas a lhes proporcionar um prognóstico e encaminhamento adequados para que o desfecho da gestação seja favorável tanto para elas quanto para seus bebês.
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Pérez, Fernández Virginia. "Los modelos multinivel en el análisis de factores de riesgo de sibilancias recurrentes en lactantes. Enfoques frecuentista y bayesianao." Doctoral thesis, Universidad de Murcia, 2012. http://hdl.handle.net/10803/109213.
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En esta tesis se han mostrado los conceptos fundamentales de la metodología multinivel, y se han desarrollado los enfoques frecuentista y bayesiano para el análisis de los modelos multinivel logísticos de 2 niveles. Se ha realizado un estudio comparativo entre un método de análisis que no tiene en cuenta la estructura jerárquica de los datos y los métodos multinivel para el análisis de los factores de riesgo de las sibilancias recurrentes en lactantes. Se han comparado los enfoques frecuentista y bayesiano tanto para el análisis de los modelos multinivel de 2 niveles completamente aleatorios, con intercepto y pendiente aleatoria, como para los modelos de 2 niveles con intercepto aleatorio y variables explicativas del primer nivel y del segundo nivel. El resultado obtenido es que los modelos multinivel mejoran la precisión de las estimaciones de los parámetros respecto a los modelos que no tienen en cuenta la estructura jerárquica de los datos<br>This thesis shows the fundamental concepts of the multilevel methodology, and the frequentist and bayesian approaches for multilevel models for binary responses. A comparative study between a method of analysis which does not consider the hierarchical structure of the data and two multilevel methods when applied to study of wheezing and its risk factors in the first year of life. A bayesian and frequentist methods were compared for fitting a two-level random slope model, with random intercept and random slope, and for a random intercept model with a two level explanatory variables. The results show that the multilevel models improve estimations accuracy of parameters regarding models which do not consider the hierarchical structure of the data.
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Maximiano, Nilcilene. "Perfil materno-infantil de nascimentos por parto duplo em uma amostra de puerperas no municipio do Rio de Janeiro, 1999-2001." Rio de Janeiro : [s.n.], 2002. http://teses.cict.fiocruz.br/pdf/maximianonm.pdf.
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Toledo, Hernández Cecília [UNESP]. "Modelo de gerenciamento da logística reversa integrado às questões estratégicas das organizações." Universidade Estadual Paulista (UNESP), 2010. http://hdl.handle.net/11449/106428.
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toledohernandez_c_dr_guara.pdf: 1092055 bytes, checksum: 0b2c543a0058afd866f34854073b41e5 (MD5)<br>Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)<br>O aumento do número de produtos com vida útil menor, a intensificação no uso do comércio eletrônico, leis cada vez mais exigentes de responsabilidade sobre descarte dos produtos e uma crescente consciência ambiental têm gerado um elevado número de retornos, fazendo crescer a importância da Logística Reversa para as empresas e para a sociedade, de forma geral. Contudo, constatou-se na literatura que se trata de uma área ainda pouco explorada, que carece de histórico e estatísticas que a mapeiem e, portanto, não existem dados concretos para se trabalhar e explorar as oportunidades de melhoria. Com o intuito de mitigar esta carência, foi realizada uma pesquisa bibliográfica acerca da relação entre a Logística Reversa e o desempenho empresarial, bem como uma pesquisa junto às empresas procurando verificar como se dá este relacionamento. A utilização de um método de pesquisa misto com estratégia exploratória possibilitou captar informação sobre os programas e atividades específicas da Logística Reversa nas empresas brasileiras. Como resultados principais desta tese obteve-se um modelo conceitual para abordar a Logística Reversa na estratégia das organizações e um conjunto de indicadores que possibilitam avaliar o seu desempenho. Adotou-se um Método de Tomada de Decisão com Múltiplos Critérios para ajudar na escolha dos indicadores, que foi a chave para o funcionamento adequado do modelo proposto. A validação do modelo, junto a especialistas das empresas envolvidas na pesquisa, demonstrou que seu uso é factível e que ele oferece alternativas sobre como intervir nas atividades da Logística Reversa no sentido de alinhá-la aos objetivos estratégicos das empresas.<br>The increase in the number of items with a lower useful life, the massive use of ecommerce, an increased environmental awareness and increasingly demanding laws on disposal of products responsibility, has created a elevated number of returns, making to grow the importance of Reverse Logistics for society and companies, in a general fashion. It was found in the literature, however, that Reverse Logistics is still a poorly explored activity, without historical and statistical data that maps it and consequently, there is no concrete data to work with and to explore the opportunities for improvement. With the goal of minimizing this deficiency, a bibliographic research about the relation between the Reverse Logistics and the business performance was made, besides a research along the companies seeking to verify how this relationship is made. Using a mixed research method with exploratory strategy allowed picking up information about the programs and specific activities of Reverse Logistics in Brazilian companies. As the main result of this thesis, a conceptual model for addressing the Reverse Logistics in the organizations strategy and a set of indicators that allow assessing their performance was obtained. A Multiple Criteria Decision Making was adopted to help in the choice of indicators, which was the key to the proper functioning of the proposed model. The validation of the model, along with experts from companies involved in research, has demonstrated that its use is feasible and it offers alternatives on how to intervene in the activities of Reverse Logistics in order to align it with the strategic objectives of companies.
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Silva, Cleide Aparecida Moreira. "Exploração de metodos de seleção de variaveis pela tecnica de regressão logistica para analise de dados epidemiologicos." [s.n.], 2006. http://repositorio.unicamp.br/jspui/handle/REPOSIP/313543.
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Orientador: Djalma de Carvalho Moreira Filho<br>Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Ciencias Medicas<br>Made available in DSpace on 2018-08-07T04:15:04Z (GMT). No. of bitstreams: 1
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Previous issue date: 2006<br>Resumo: Neste trabalho foi discutida a aplicação de dois métodos distintos de seleção de variáveis e modelos na análise de regressão logística múltipla: modelo hierarquizado e modelo selecionado pelo critério stepwise. Em um estudo caso-controle não-pareado realizado para identificar fatores de risco para o óbito neonatal em Campinas-SP foram analisadas variáveis sócio-econômicas, de morbidade materna e relacionadas à atenção à saúde. Foram selecionados 117 casos e 234 controles e as informações adicionais obtidas por meio de entrevista domiciliar. Pela análise de regressão logística múltipla com modelo hierarquizado foram identificados como fatores de risco para o óbito neonatal a renda familiar, a naturalidade da mãe, o número de moradores do domicílio, presença de sangramento vaginal, parto antecipado por problema de saúde, o número de orientações recebidas durante o pré-natal, a escolha do hospital para o parto, o tempo entre a internação e o parto, a idade gestacional, baixo peso ao nascer e Apgar do quinto minuto. As diferenças encontradas no modelo selecionado pelo critério stepwise foram: renda familiar que se mostrou associada à escolha do hospital, internação por problemas de saúde associada ao sangramento vaginal e naturalidade da mãe, contemplada apenas no modelo hierarquizado e associada ao parto precipitado. Houve também a inclusão de uma interação entre número de orientações recebidas e parto precipitado. A modelagem hierarquizada permitiu que variáveis associadas entre si ficassem no modelo final (colinearidade). A exploração das relações entre as variáveis foi realizada quando se empregou o procedimento stepwise. Independentemente da escolha do processo de seleção de variáveis ou modelo existem pontos que devem ser relevados: revisão exaustiva da literatura sobre o evento em estudo, análise univariada cuidadosa e avaliação das inter-relações ente as variáveis<br>Abstract: n this work it was discussed the application of two methods for selection of predictor variables and models in multiple logistic regression analysis: hierarchical model and a stepwise model. In a case-control study conduced to identify risk factors associated to neonatal mortality in Campinas, São Paulo, the effects of socio-economic, maternal morbidity and health care were studied. The study included 117 cases and 234 controls and the supplementary data were obtained from household interviews. The multiple logistic regression analysis, in a hierarchical model, identified as associated to neonatal death risk: income, immigration, number of dwellers, the choice of delivery hospital, vaginal bleeding, early delivery due to health problems, time elapsed between hospital admission and delivery, number of orientations received, gestational age, low birth weight and APGAR score at 5th minute. The differences found for the stepwise model were: income was associated with the choice of delivery hospital, vaginal bleeding was associated with early delivery due to health problems and immigration. Immigration was selected only by the hierarchical model and was associated with early delivery due to health problems. A interaction effect between number of orientations received and early delivery due to health problems was included in model selected by the stepwise procedure. The hierarchical modeling allowed associated variables to be in the final model (collinearity). The inter-relation between variables was investigated with the stepwise procedure. Independently of the choice of the process of selection of variables or models there are points that are important: exhaustive literature review, a careful univariate analysis and the evaluation of the relationships between two or more independent variables<br>Mestrado<br>Saude Coletiva<br>Mestre em Saude Coletiva
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Deilami, Moezi Sarem. "Optimization Models in Logistics." Doctoral thesis, Università degli studi di Bergamo, 2018. http://hdl.handle.net/10446/105201.
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In this thesis, we study three problems in logistics: Single Link Shipping, Vendor-Managed
Inventory (VMI) and Scheduling. Firstly, we review the single link shipping problem in the case
of multi-product and multi-modal shipping with given sets of frequencies and lead times. The
contribution is on the single link case, that is due to the introduction of different sets of frequencies
for each type of vehicles and to the introduction of lead times. Secondly, we introduce a two-echelon
vendor-buyer supply chain model under VMI, which is more applicable to real-world inventory
control systems. Then, considering that the objective function is very complex to solve exactly
by using conventional techniques, some solution algorithms are used. Finally, we introduce the
problem of scheduling on a single machine with focusing on Early/Tardy problem with distinct
due dates. Then, an INLP model is formulated and an algorithm is developed in order to solve
the single machine earliness and tardiness problem. For all the three problems, numerical results
are discussed.
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Rychnovský, Michal. "Scoring Models in Finance." Master's thesis, Vysoká škola ekonomická v Praze, 2011. http://www.nusl.cz/ntk/nusl-72256.
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The aim of the present work is to describe the application of the logistic regression model to the field of probability of default modeling, and provide a brief introduction to the scoring development process used in financial practice. We start by introducing the theoretical background of the logistic regression model; followed by a consequent derivation of three most common scoring models. Then we present a formal definition of the Gini coefficient as a diversification power measure and derive the Somers-type formulas for its estimation. Finally, the key part of this work gives an overview of the whole scoring development process illustrated on the examples of real business data.
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Coleti, Jamile de Campos 1991. "Transporte e intermodalidade do etanol brasileiro : uma aplicação de um modelo de equilíbrio parcial." [s.n.], 2015. http://repositorio.unicamp.br/jspui/handle/REPOSIP/286540.
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Orientador: Andrea Leda Ramos de Oliveira<br>Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Economia<br>Made available in DSpace on 2018-08-27T05:17:03Z (GMT). No. of bitstreams: 1
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Previous issue date: 2015<br>Resumo: A busca por fontes de energia renováveis tem aumentado a demanda mundial de etanol. O Brasil ocupa a posição de segundo maior produtor mundial de etanol, porém os custos para transportar essa produção são cada vez mais altos. Estima-se que os custos de transportes podem representar até 30% do valor total do produto para cargas agrícolas. Isto posto, o objetivo do trabalho é analisar as alternativas de transporte do etanol frente às condições logísticas vigentes no Brasil. Para tanto, propõe-se um modelo de equilíbrio parcial na forma de um Problema de Complementaridade Mista (PCM) aplicado ao etanol. Avaliaram-se três cenários distintos: o primeiro é o cenário base com rotas de transporte utilizando o modal rodoviário e intermodal; já o segundo estimou-se uma redução de 15% no valor do frete ferroviário; e no terceiro inclui-se novos projetos dutoviários em curso no país. O Cenário 3 apresentou os melhores resultados em termos de volume de comercialização, com um aumento de 0,20% em relação ao cenário base, indicando que os projetos viários que priorizam a intermodalidade, sobretudo através da dutovia, implicam em reduções no custo de transporte e conferem uma melhoria na eficiência do sistema logístico. Destaca-se também, que as hipóteses de intermodalidade dos cenários 2 e 3 refletiram-se em ganhos de competitividade no mercado internacional, isso porque 100% das rotas com destino ao mercado externo são intermodais, conclui-se então, que a intermodalidade acaba apresentando custos de transporte reduzidos e portanto, mostra-se mais competitiva<br>Abstract: The search for renewable energy sources has been increasing the global demand for ethanol. Brazil holds the position as the second largest world producer of ethanol, but the costs to transport this production are increasingly high. It is estimated that transport costs can represent up to 30% of the total value of the product for agricultural loads. That said, this study aimed is to analyze the ethanol transportation alternatives front to the logistics conditions prevailing in Brazil. To this end, it is proposed a partial equilibrium model as a Mixed Complementarity Problem (PCM) applied to ethanol. It was evaluated three different scenarios: the first it is a baseline scenario with shipping routes with road and intermodal modal, the second estimated that the 15% reduction in the value of rail freight and the third is included new pipelines projects in course in the country. The Scenario 3 presented the best results in terms of marketing volumes, with an increase of 0.20% compared to baseline, indicating that the road projects that priorize intermodality, especially through the pipeline, implying reductions in the cost of transport and provide an improvement in efficiency the logistics system. Also noteworthy is that the chance of intermodal scenarios two and three reflected in gains in competitiveness in the international market, this because 100% of the routes to the foreign market are intermodal, it is concluded that, intermodality just showing reduced transport costs and therefore shows to be more competitive<br>Mestrado<br>Desenvolvimento Economico, Espaço e Meio Ambiente<br>Mestra em Desenvolvimento Econômico
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Oliveira, Adalberto Luís Rodrigues de. "Otimização de recebimento e distribuição em unidades armazenadoras de soja." Universidade Federal do Paraná, 2005. http://repositorio.utfpr.edu.br/jspui/handle/1/767.
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Esse estudo tem por finalidade elaborar um modelo matemático para a maximização da receita proveniente da logística, estratégias do processo de obtenção, recebimento, armazenamento e distribuição de grãos visando a posterior comercialização ou exportação, quando o preço esperado poderá ser mais levado em função da sazonalidade e apresenta um programa computacional. Para tanto, foram abordados os aspectos teóricos dos métodos para a resolução de Problemas de Roteamento e Localização. Além disso, foi feito um detalhamento do Método de Roteamento de forma mais aplicada, bem como a descrição da forma utilizada para a distribuição da soja pela empresa Campagro. O programa computacional criado, bem como sua proposta de avaliação, foi aplicado a um conjunto de dados que envolveu 494 produtores da cidade de Campo Mourão e região e 7 entrepostos. O modelo elaborado, que levou em consideração principalmente a clusterização, mostrou que esse método faz com que haja um menor gasto de tempo e considera a menor distância possível entre entrepostos e produtores.<br>The following study whose objective is to elaborate a mathematics model to the maximization of the budget coming from the logistics, strategies of acquiring, receiving, storage and distribution process aiming the sale or exportation in order to get a higher price according to the season and presents a computational program. Thus, it was mentioned theoretical features of methods for solving the Localization and outing Problems. Besides that, it was accomplished a more applied detailing of the Routing Method as well as the description of the used form of distribution of soybean by Campagro company. The computational program and its evaluation proposal were applied to a set of data including 494 farmers of Campo Mourão and its region and 7 grains stores. The accomplished model, which considered mainly the clusterization, has shown that the use of such method provides time saving and it considers the smallest distance between the grains stores and the producers.
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Soto, Zuluaga Juan Pablo. "Reverse logistics: models and applications." Doctoral thesis, Universitat Pompeu Fabra, 2006. http://hdl.handle.net/10803/7338.
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En los últimos años la Logística Inversa se ha hecho relevante no solo para el mundo académico sino también para el empresarial. Las empresas dan cada día más importancia a esta área, debido a los factores medioambientales y a los beneficios derivados del mejoramiento de su proceso de devoluciones. Así mismo, para tener unos procesos de Logística Inversa eficientes y exitosos, es necesaria la colaboración entre los miembros de la cadena de suministro. Esta tesis se concentra en ambos aspectos, Colaboración y Logística Inversa.<br/>El propósito de esta tesis es doble; primero, analizar los problemas que sufren hoy en día las empresas en esta área, partiendo de una perspectiva general, y posteriormente analizando la industria editorial española. En segundo lugar, nosotros proponemos cuatro modelos matemáticos concernientes a los problemas de planificación que presentan las empresas cuando incorporan las devoluciones, y finalmente proponemos unas metodologías para solucionarlos.<br>During last years Reverse Logistics has become a relevant topic not only for academics but also for the business world. Companies are giving each day more and more importance to this field, because the environmental issues and the benefits that the company can obtain by the improvement of their return's processes. To obtain a successful and efficient Reverse Logistics processes there exist the need to collaborate along the supply chain. This thesis focuses on both of these two topics, Collaboration and Reverse Logistics. <br/>The aim of this thesis is twofold; first, we try to understand the returns processes' problems that companies are facing today from the management point of view, from a general perspective and afterwards on the editorial industry. Secondly, we propose some mathematical models and solution methods related to real planning problems faced by the companies when the returns are incorporated.
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Falasca, Mauro. "Quantitative Decision Models for Humanitarian Logistics." Diss., Virginia Tech, 2009. http://hdl.handle.net/10919/28774.
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Humanitarian relief and aid organizations all over the world implement efforts aimed at recovering from disasters, reducing poverty and promoting human rights. The purpose of this dissertation is to develop a series of quantitative decision models to help address some of the challenges faced by humanitarian logistics.
The first study discusses the development of a spreadsheet-based multicriteria scheduling model for a small development aid organization in a South American developing country. Development aid organizations plan and execute efforts that are primarily directed towards promoting human welfare. Because these organizations rely heavily on the use of volunteers to carry out their social mission, it is important that they manage their volunteer workforce efficiently. In this study, we demonstrate not only how the proposed model helps to reduce the number of unfilled shifts and to decrease total scheduling costs, but also how it helps to better satisfy the volunteers’ scheduling preferences, thus supporting long-term retention and effectiveness of the workforce.
The purpose of the second study is to develop a decision model to assist in the management of humanitarian relief volunteers. One of the challenges faced by humanitarian organizations is that there exist limited decision technologies that fit their needs while it has also been pointed out that those organizations experience coordination difficulties with volunteers willing to help. Even though employee workforce management models have been the topic of extensive research over the past decades, no work has focused on the problem of managing humanitarian relief volunteers. In this study, we discuss a series of principles from the field of volunteer management and develop a multicriteria optimization model to assist in the assignment of both individual volunteers and volunteer groups to tasks. We present illustrative examples and analyze two complementary solution methodologies that incorporate the decision maker's preferences and knowledge and allow him/her to trade-off conflicting objectives.
The third study discusses the development of a decision model for the procurement of goods in humanitarian efforts. Despite the prevalence of procurement expenditures in humanitarian efforts, procurement in humanitarian contexts is a topic that has only been discussed in a qualitative manner in the literature. In our paper, we introduce a two stage decision model with recourse to improve the procurement of goods in humanitarian relief supply chains and present an illustrative example. Conclusions, limitations, and directions for future research are also discussed.<br>Ph. D.
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Pereira, Juliana Rodrigues Dionisio. "Estabilidade assintótica de modelos logísticos com retardamento." Universidade de São Paulo, 2013. http://www.teses.usp.br/teses/disponiveis/55/55135/tde-12122013-095120/.
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Esta dissertação tem como objetivo principal estudar a estabilidade assintótica de Equações Diferenciais com Retardamento utilizando as técnicas desenvolvidas por Faria e Liz (2003). Para analisar a estabilidade assintótica, a abordagem utilizada neste trabalho é a de impor uma condição de dominância do termo sem retardo sobre a parte com retardo, possibilitando o estudo de soluções oscilatórias. Além disso, o estudo culminará em um teorema que garante essa estabilidade em uma Equação do tipo Lotka-Volterra, para a qual o método de Liapunov não se aplica. Para atingir o objetivo, estudou-se inicialmente a teoria geral de estabilidade de Equações Diferenciais Funcionais e a teoria de estabilidade para alguns tipos dessas equações<br>This paper\'s main objective is to study the asymptotic stability of Dierential Equations with Delay using the techniques developed by Faria and Liz (2003). To analyze the asymptotic stability, the approach used in this study is to impose a condition of dominance of the term without delay on the part delayed, allowing the study of oscillatory solutions. In addition, the study will culminate in a theorem ensures such stability in an equation Lotka-Volterra type, for which the Liapunov method does not apply. To achieve the objective, we studied initially the general theory of stability of Functional Dierential Equations and stability theory for some types of these equations
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Accorsi, Riccardo. "Integrated Models and Tools for Design and Management of Global Supply Chain." Doctoral thesis, Università degli studi di Padova, 2013. http://hdl.handle.net/11577/3422615.
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In modern and global supply chain, the increasing trend toward product variety, level of service, short delivery delay and response time to consumers, highlight the importance to set and configure smooth and efficient logistic processes and operations.
In order to comply such purposes the supply chain management (SCM) theory entails a wide set of models, algorithms, procedure, tools and best practices for the design, the management and control of articulated supply chain networks and logistics nodes.
The purpose of this Ph.D. dissertation is going in detail on the principle aspects and concerns of supply chain network and warehousing systems, by proposing and illustrating useful methods, procedures and support-decision tools for the design and management of real instance applications, such those currently face by enterprises.
In particular, after a comprehensive literature review of the principal warehousing issues and entities, the manuscript focuses on design top-down procedure for both less-than-unit-load OPS and unit-load storage systems. For both, decision-support software platforms are illustrated as useful tools to address the optimization of the warehousing performances and efficiency metrics. The development of such interfaces enables to test the effectiveness of the proposed hierarchical top-down procedure with huge real case studies, taken by industry applications.
Whether the large part of the manuscript deals with micro concerns of warehousing nodes, also macro issues and aspects related to the planning, design, and management of the whole supply chain are enquired and discussed.
The integration of macro criticalities, such as the design of the supply chain infrastructure and the placement of the logistic nodes, with micro concerns, such the design of warehousing nodes and the management of material handling, is addressed through the definition of integrated models and procedures, involving the overall supply chain and the whole product life cycle.
A new integrated perspective should be applied in study and planning of global supply chains. Each aspect of the reality influences the others. Each product consumed by a customer tells a story, made by activities, transformations, handling, processes, traveling around the world. Each step of this story accounts costs, time, resources exploitation, labor, waste, pollution. The economical and environmental sustainability of the modern global supply chain is the challenge to face.<br>Nelle moderne filiere logistiche-distributive globali, la crescente varietà dei prodotti, il livello di servizio, e la rapidità nel rispondere alla domanda del cliente, impongono una seria e ponderata progettazione ed organizzazione dei processi intra-inter aziendali. Con l'obiettivo di rispondere a tali criticità, le teorie di supply chain managment (SCM) propongono una vasta gamma di modelli, algoritmi, procedure, e strumenti per la progettazione, la gestione e il controllo delle articolate supply chain e dei principali nodi logistici.
Uno dei principali obiettivi di questa tesi di dottorato è approfondire nel dettaglio i processi e gli aspetti principali della filiera logistica e dei suoi principali buffer (i.e. sistemi di stoccaggio), illustrando metodi, modelli, procedure e sistemi di supporto decisionale per la progettazione e gestione di istanze reali, quotidianamente affrontate dalle aziende di tutto il mondo.
In particolare, dopo una completa rassegna della letteratura sui sistemi di stoccaggio, la tesi si concentra sulla descrizione di procedure decisionali top-down per la progettazione ed il controllo di sistemi di stoccaggio a prelievo frazionato (i.e. Order picking systems) e sistemi di stoccaggio ad unità di carico intere. Per entrambe le tipologie di sistemi, sono illustrati strumenti informatici di supporto alle decisioni per la valutazione e l'ottimizzazione delle prestazioni logistiche - operative. Lo sviluppo di tali interfacce permette di testare l'efficacia dei modelli e delle procedure decisionali proposte su significativi casi di studio di origine industriale.
Se la prima parte del manoscritto si concentra sugli aspetti micro intra-nodo della filiera distributiva, l'ultimo capitolo affronta le tematiche macro di filiera relative alla pianificazione, progettazione e gestione della infrastruttura della supply chain.
L'integrazione di macro criticità, come la locazione dei nodi logistici di produzione e distribuzione e l'instradamento dei flussi fisici lungo ed attraverso il network della supply chain, con micro criticità, inerenti la progettazione di nodi distributivi e di stoccaggio e la gestione del material handling, si realizza attraverso la definizione di modelli integrati di pianificazione strategica per l'ottimizzazione dell'intera filiera, lungo tutto il ciclo di vita del prodotto.
Una nuova prospettiva integrata deve essere applicata allo studio e la progettazione di articolate supply chain globali. Ogni aspetto della realtà dipende ed influenza gli altri lungo la filiera. Ogni prodotto acquistato e consumato dal cliente finale racconta una storia, fatta di attività, processi, trasformazioni subite, movimentazioni e trasporto in giro per il mondo. Ogni step di questo percorso richiede tempo, risorse, manodopera, generando costi, scarti, inquinamento.
In tale contesto, la sostenibilità economica ed ambientale delle moderne supply chain globali rappresenta la principale sfida da affrontare.
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Nori, Vijay S. "Algorithms for dynamic and stochastic logistics problems." Diss., Georgia Institute of Technology, 1999. http://hdl.handle.net/1853/24513.
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Andersson, Anja. "Logistic process models for Swedtrac." Thesis, Linköpings universitet, Kommunikations- och transportsystem, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-102751.
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Detta examensarbete har utförts hos Swedtrac Trafik AB som är ett dotterbolag till Swedtrac AB. Swedtrac Trafik AB har trafikutövartillstånd och erbjuder utbildningar inom alla trafiksäkerhetsrelaterade delar av järnvägsverksamheten. Företaget har också verksamhet som löser kundernas transportbehov. Swedtrac Trafik AB baserar sin verksamhetsutveckling på processer vilket innebär att en processorienterad verksamhetsstyrning behövs för att klara dagens allt intensivare konkurrens på en global marknad. Därför är en initial processmall nödvändig. Syftet med detta examensarbete är att kartlägga nuvarande processer och göra en processmall/ett flödesschema från kundbeställning till slutprodukt samt ge en klar bild över var i processerna det finns möjlighet till effektivisering. Detta arbete är en studie av företagets processer med utvald processkartläggningsmetod. I metoden ingår studiebesök, telefon- grupp- och personlig intervju. Resultatet från dessa sammanställningar ger en djupare insyn i den nuvarande processen. Vid processkart-läggningen utgår arbetet från två vinklar: den ena är en ”as-is” process (swim lane chart) som utifrån beskrivningar från avdelningarnas intervjuer har ritats upp ett flöde över nuläget. Den andra är en ”to-be” process där problem som hittas i nulägesflödet har getts förslag på åtgärder. Processkarläggningen bygger på en SS-modell(sjustegsmodell). Varje steg bidrar till processmallen och har sitt eget syfte, mål och ett centralt värde för processkartläggningen. Resultatet består av två processmallar samt förbättringsförslag för nuläget och för framtiden. Förbättringsförslagen baseras på en processanalys av ”as-is” och ”to-be” processen. Processmallarna konstrueras med hjälp av modelleringsspråket ”BPMN”. Genom att jämföra de två processerna kan problem och förbättringsmöjligheter identifieras. När onödiga aktiviteter eliminerats och icke värdeskapande aktiviteter ändrats till värdeskapande, leder det till en minskning av administrativa kostnader samt att processens förmåga och effektiviteter förbättras. Detta innebär att processen kommer att utvecklas till en mer värdeskapande process.
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Rashid, Mamunur. "Inference on Logistic Regression Models." Bowling Green State University / OhioLINK, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1214165101.
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Shen, Su 1973. "Logistics service network design : models, algorithms, and applications." Thesis, Massachusetts Institute of Technology, 2004. http://hdl.handle.net/1721.1/29424.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2004.<br>Includes bibliographical references (leaves 177-186).<br>Service network design is critical to the profitability of express shipment carriers. In this thesis, we consider two challenging problems associated with designing networks for express shipment service. The first problem is to design an integrated network for premium and deferred services simultaneously. Related existing models adapted to this problem are intractable for realistic instances of this problem: computer memory requirements and solution times are excessive. We introduce a disaggregate information-enhanced column generation approach for this problem that reduces the number of variables to be considered in the integer program from hundreds of thousands to only thousands, allowing us to solve previously unsolvable problem instances. The second problem is to determine the express package service network design in its entirety, including aircraft routings, fleet assignments, and package flow routings, including hub assignments. Existing models applied to this problem have weak associated linear programming bounds and hence, fail to produce quality feasible solutions. For example, for a small network design problem instance it takes days to produce a feasible solution that is provably near- optimal using the best performing existing model. To overcome these tractability challenges, we introduce a new model, referred to as the gateway cover and flow formulation. Applying our new formulation to the same network design instance, it takes only minutes to find an optimal solution.<br>(cont.) Applying our disaggregate information-enhanced column generation approach and gateway cover and flow formulation and solution approach to the network design problems of a large express package service provider, we demonstrate tens of millions of dollars in potential annual operating cost savings and reductions in the numbers of aircraft needed to perform the service. Moreover, we illustrate that, though designed for tactical planning, our new model and solution approach can provide insights for strategic decision-making, such as hub opening/closure, hub capacity expansion, and fleet composition and size.<br>by Su Shen.<br>Ph.D.
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Andriolo, Alessandro. "Responsible Inventory Models for Operation and Logistics Management." Doctoral thesis, Università degli studi di Padova, 2015. http://hdl.handle.net/11577/3424091.
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The industrialization and the subsequent economic development occurred in the last century have led industrialized societies to pursue increasingly higher economic and financial goals, laying temporarily aside the safeguard of the environment and the defense of human health. However, over the last decade, modern societies have begun to reconsider the importance of social and environmental issues nearby the economic and financial goals. In the real industrial environment as well as in today research activities, new concepts have been introduced, such as sustainable development (SD), green supply chain and ergonomics of the workplace. The notion of “triple bottom line” (3BL) accounting has become increasingly important in industrial management over the last few years (Norman and MacDonald, 2004). The main idea behind the 3BL paradigm is that companies’ ultimate success should not be measured only by the traditional financial results, but also by their ethical and environmental performances. Social and environmental responsibility is essential because a healthy society cannot be achieved and maintained if the population is in poor health. The increasing interest in sustainable development spurs companies and researchers to treat operations management and logistics decisions as a whole by integrating economic, environmental, and social goals (Bouchery et al., 2012).
Because of the wideness of the field under consideration, this Ph.D. thesis focuses on a restricted selection of topics, that is Inventory Management and in particular the Lot Sizing problem. The lot sizing problem is undoubtedly one of the most traditional operations management interests, so much so that the first research about lot sizing has been faced more than one century ago (Harris, 1913).
The main objectives of this thesis are listed below:
1) The study and the detailed analysis of the existing literature concerning Inventory Management and Lot Sizing, supporting the management of production and logistics activities. In particular, this thesis aims to highlight the different factors and decision-making approaches behind the existing models in the literature. Moreover, it develops a conceptual framework identifying the associated sub-problems, the decision variables and the sources of sustainable achievement in the logistics decisions. The last part of the literature analysis outlines the requirements for future researches.
2) The development of new computational models supporting the Inventory Management and Sustainable Lot Sizing. As a result, an integrated methodological procedure has been developed by making a complete mathematical modeling of the Sustainable Lot Sizing problem. Such a method has been properly validated with data derived from real cases.
3) Understanding and applying the multi-objective optimization techniques, in order to analyze the economic, environmental and social impacts derived from choices concerning the supply, transport and management of incoming materials to a production system.
4) The analysis of the feasibility and convenience of governmental systems of incentives to promote the reduction of emissions owing to the procurement and storage of purchasing materials. A new method based on the multi-objective theory is presented by applying the models developed and by conducting a sensitivity analysis. This method is able to quantify the effectiveness of carbon reduction incentives on varying the input parameters of the problem.
5) Extending the method developed in the first part of the research for the “Single-buyer” case in a "multi-buyer" optics, by introducing the possibility of Horizontal Cooperation. A kind of cooperation among companies in different stages of the purchasing and transportation of raw materials and components on a global scale is the Haulage Sharing approach which is here taken into consideration in depth.
This research was supported by a fruitful collaboration with Prof. Robert W. Grubbström (University of Linkoping, Sweden) and its aim has been from the beginning to make a breakthrough both in the theoretical basis concerning sustainable Lot Sizing, and in the subsequent practical application in today industrial contexts.<br>L’industrializzazione ed il conseguente sviluppo economico avvenuti nello scorso secolo hanno spinto le società industrializzate a perseguire obiettivi economico-finanziari sempre più alti, mettendo momentaneamente in secondo piano la tutela per l’ambiente e per la salute umana. Tuttavia, nel corso dell’ultimo decennio le moderne società hanno cominciato a riconsiderare l’importanza degli aspetti sociali ed ambientali contestualmente agli obiettivi economici. Nel mondo industriale, così come nell’attività di ricerca scientifica odierna, sono stati introdotti nuovi concetti quali lo sviluppo sostenibile, la green supply chain e l’ergonomia dei posti di lavoro. La nozione di “triple bottom line” (3BL) è divenuta sempre più importante nella gestione industriale negli ultimi anni (Norman and MacDonald, 2004). L’idea che sta alla base del concetto di 3BL è che il successo finale di una azienda non dovrebbe essere misurato solo in termini di risultati finanziari, ma anche dai risultati in ambito etico ed ambientale. I concetti di responsabilità sociale ed ambientale sono oggi essenziali poiché una società forte e sana non si può realizzare e mantenere se i singoli individui che la compongono non godono di ottima salute. L’interesse crescente verso lo sviluppo sostenibile spinge il mondo industriale e della ricerca scientifica a trattare i problemi di operations management con un approccio integrato, in modo da inglobare in un’unica procedura obiettivi economici, ambientali e sociali (Bouchery et al., 2012).
Vista la vastità degli aspetti contemplati dal settore, in questa tesi di dottorato si affronterà solo una parte ristretta dei molteplici aspetti in gioco, quelli della gestione delle scorte di magazzino e più in dettaglio della determinazione del lotto economico. Si tratta senza dubbio di uno dei problemi più tradizionali in ambito di operations management, tanto che il primo problema di lot sizing è stato affrontato più di un secolo fa (Harris, 1913).
Questo lavoro di tesi si pone i seguenti obiettivi principali:
1) Lo studio e l’analisi dettagliata della letteratura riguardante i problemi di Inventory Management e Lot Sizing a supporto della gestione delle attività produttive e logistiche. In particolare dopo aver analizzato i diversi fattori e approcci decisionali alla base dei modelli esistenti in letteratura, lo sviluppo di un innovativo framework concettuale identifica i sotto-problemi associati, le variabili decisionali e i principali aspetti che influenzano la sostenibilità nelle decisioni logistiche, aiutando a delineare i requisiti delle ricerche future.
2) L’elaborazione di nuovi modelli di calcolo a supporto dell’Inventory Management e del Lot Sizing sostenibile. A questo scopo è stata sviluppata una nuova procedura metodologica, elaborando un’applicazione matematica completa del metodo di Lot Sizing Sostenibile. Tale metodo è stato opportunamente validato con dati provenienti da casi reali.
3) La comprensione e l’applicazione delle tecniche di ottimizzazione multi-obiettivo al fine di analizzare l’impatto economico, ambientale e sociale nelle scelte di approvvigionamento, trasporto e gestione dei materiali in ingresso ad un sistema produttivo.
4) L’analisi della fattibilità e convenienza di sistemi governativi di incentivazione per promuovere la riduzione delle emissioni ambientali dovute alle attività di approvvigionamento e stoccaggio dei materiali di acquisto. Sfruttando i modelli sviluppati e conducendo una analisi di sensitività, è stato sviluppato un metodo basato sulla teoria multi-obiettivo per quantificare l’effetto di incentivi per la riduzione delle emissioni in relazione ai parametri in ingresso del problema.
5) L’estensione del metodo sviluppato per il caso di approvvigionamento tradizionale “Single-Buyer”, in ottica “multi-buyer” introducendo la possibilità di Cooperazione Orizzontale e Haulage Sharing da parte di aziende diverse nelle fasi di acquisto e trasporto di materia prima e componenti su scala globale.
Questo lavoro di ricerca è stato supportato da una proficua collaborazione con il Prof. Robert W. Grubbström (University of Linkoping, Svezia), e fin dall’inizio si è posto l’obiettivo di apportare un’innovazione sia nella base teorica riguardante il Lot Sizing sostenibile, sia nella conseguente applicazione pratica in contesti industriali a noi contemporanei.
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Jánoš, Andrej. "Vývoj kredit skóringových modelov s využitím vybraných štatistických metód v R." Master's thesis, Vysoká škola ekonomická v Praze, 2016. http://www.nusl.cz/ntk/nusl-262242.
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Credit scoring is important and rapidly developing discipline. The aim of this thesis is to describe basic methods used for building and interpretation of the credit scoring models with an example of application of these methods for designing such models using statistical software R. This thesis is organized into five chapters. In chapter one, the term of credit scoring is explained with main examples of its application and motivation for studying this topic. In the next chapters, three in financial practice most often used methods for building credit scoring models are introduced. In chapter two, the most developed one, logistic regression is discussed. The main emphasis is put on the logistic regression model, which is characterized from a mathematical point of view and also various ways to assess the quality of the model are presented. The other two methods presented in this thesis are decision trees and Random forests, these methods are covered by chapters three and four. An important part of this thesis is a detailed application of the described models to a specific data set Default using the R program. The final fifth chapter is a practical demonstration of building credit scoring models, their diagnostics and subsequent evaluation of their applicability in practice using R. The appendices include used R code and also functions developed for testing of the final model and code used through the thesis. The key aspect of the work is to provide enough theoretical knowledge and practical skills for a reader to fully understand the mentioned models and to be able to apply them in practice.
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Huang, Wei. "Optimization models for sourcing decisions in supply chain management." [Gainesville, Fla.] : University of Florida, 2004. http://purl.fcla.edu/fcla/etd/UFE0006605.
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Zegarra, Sofia Lilianne Villagarcia. "Diretrizes para a elaboração de um modelo de gestão dos fluxos de informações como suporte à logística em empresas construtoras de edifícios." Universidade de São Paulo, 2000. http://www.teses.usp.br/teses/disponiveis/3/3146/tde-18012002-111909/.
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Este trabalho objetiva propor diretrizes para a elaboração de um modelo de gestão de fluxo de informações como suporte à logística em empresas construtoras de edifícios. O foco da pesquisa limita-se especificamente à gestão de materiais, apesar da logística também abranger mão-de-obra, serviços e equipamentos. O objetivo da gestão de materiais é o de assegurar um fluxo continuo e sem interferências de materiais e componentes à obra, na quantidade requerida, com a qualidade especificada, no tempo e lugar certo, ao menor custo total. Estas diretrizes foram identificadas visando a uma integração funcional dentro da empresa construtora. Com base em um estudo de caso realizado em três empresas construtoras e em um levantamento e estudo bibliográfico, foram estudados os fluxos de informações ligados à gestão de materiais que ocorrem dentro das empresas construtoras. Desta maneira, identificaram-se os principais fatores que facilitam e que dificultam os fluxos de informações entre agentes relacionados com a gestão de materiais. Uma vez analisados estes fatores, foram identificadas as diretrizes objeto desta pesquisa e foi proposto um fluxo de informações modelo baseado exclusivamente nos casos estudados. Adicionalmente, foram discutidos alguns parâmetros a se levar em conta para avaliar o modelo proposto e conseguir uma melhoria continua dentro do processo. Também, foi brevemente discutida a forma como as parcerias com os fornecedores, o uso de produtos normalizados, a Internet e os códigos de barras poderiam inovar estes fluxos de informações e conseguir a integração tão almejada na cadeia de suprimentos.<br>This research aims to identify guidelines for developing an information flow management model to support materials management in building construction firms. The main purpose of building materials management is to have the required materials at the right place, at the right time, in the right quantity without prejudicing cost and quality. These guidelines were identified considering a functional integration within the construction firm. Based on three case studies developed in construction firms and a literature review, the materials management information flows inside the construction firm were studied. In this way, the principal factors that affect or enhance these information flows were analyzed. Once analyzed these factors, we were able to determine the best arrange for these flows and identify the guidelines and propose an information flow model based exclusively in the three cases studied. Besides this, we discussed the parameters that should be taken into account to guarantee a continuous improvement in the model proposed. Finally, we briefly discuss how partnering with suppliers, the use of normalized products, the Internet and the use of code bars could innovate traditional information flows and integrate the supply chain.
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Batchelor, John Stephen. "Trauma scoring models using logistic regression." Thesis, University College London (University of London), 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.418022.
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GOBBATO, LUCA. "Stochastic programming for City Logistics: new models and methods." Doctoral thesis, Politecnico di Torino, 2015. http://hdl.handle.net/11583/2596359.
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The need for mobility that emerged in the last decades led to an impressive increase in the number of vehicles as well as to a saturation of transportation infrastructures. Consequently, traffic congestion, accidents, transportation delays, and polluting emissions are some of the most recurrent concerns transportation and city managers have to deal with. However, just building new infrastructures might be not sustainable because of their cost, the land usage, which usually lacks in metropolitan regions, and their negative impact on the environment. Therefore, a different way of improving the performance of transportation systems while enhancing travel safety has to be found in order to make people and good transportation operations more efficient and support their key role in the economic development of either a city or a whole country. The concept of City Logistics (CL) is being developed to answer to this need. Indeed, CL focus on reducing the number of vehicles operating in the city, controlling their dimension and characteristics. CL solutions do not only improve the transportation system but the whole logistics system within an urban area, trying to integrate interests of the several. This global view challenges researchers to develop planning models, methods and decision support tools for the optimization of the structures and the activities of the transportation system. In particular, this leads researchers to the definition of strategic and tactical problems belonging to well-known problem classes, including network design problem, vehicle routing problem (VRP), traveling salesman problem (TSP), bin packing problem (BPP), which typically act as sub-problems of the overall CL system optimization. When long planning horizons are involved, these problems become stochastic and, thus, must explicitly take into account the different sources of uncertainty that can affect the transportation system.
Due to these reasons and the large-scale of CL systems, the optimization problems arising in the urban context are very challenging. Their solution requires investigations in mathematical and combinatorial optimization methods as well as the implementation of efficient exact and heuristic algorithms. However, contributions answering these challenges are still limited number. This work contributes in filling this gap in the literature in terms of both modeling framework for new planning problems in CL context and developing new and effective heuristic solving methods for the two-stage formulation of these problems.
Three stochastic problems are proposed in the context of CL: the stochastic variable cost and size bin packing problem (SVCSBPP), the multi-handler knapsack problem under uncertainty (MHKPu) and the multi-path traveling salesman problem with stochastic travel times (mpTSPs).
The SVCSBPP arises in supply-chain management, in which companies outsource the logistics activities to a third-party logistic firm (3PL). The procurement of sufficient capacity, expressed in terms of vehicles, containers or space in a warehouse for varying periods of time to satisfy the demand plays a crucial role. The SVCSBPP focuses on the relation between a company and its logistics capacity provider and the tactical-planning problem of determining the quantity of capacity units to secure for the next period of activity. The SVCSBPP is the first attempt to introduce a stochastic variant of the variable cost and size bin packing problem (VCSBPP) considering not only the uncertainty on the demand to deliver, but also on the renting cost of the different bins and their availability. A large number of real-life situations can be satisfactorily modeled as a MHKPu, in particular in the last mile delivery. Last mile delivery may involve different sequences of consolidation operations, each handled by different workers with different skill levels and reliability. The improper management of consolidation operations can cause delay in the operations reducing the overall profit of the deliveries. Thus, given a set of potential logistics handlers and a set of items to deliver, characterized by volume and random profit, the MHKPu consists in finding a subset of items which maximizes the expected total profit. The profit is given by the sum of a deterministic profit and a stochastic profit oscillation, with unknown probability distribution, due to the random handling costs of the handlers.The mpTSPs arises mainly in City Logistics applications. Cities offer several services, such as garbage collection, periodic delivery of goods in urban grocery distribution and bike sharing services. These services require the planning of fixed and periodic tours that will be used from one to several weeks. However, the enlarged time horizon as well as strong dynamic changes in travel times due to traffic congestion and other nuisances typical of the urban transportation induce the presence of multiple paths with stochastic travel times. Given a graph characterized by a set of nodes connected by arcs, mpTSPs considers that, for every pair of nodes, multiple paths between the two nodes are present. Each path is characterized by a random travel time. Similarly to the standard TSP, the aim of the problem is to define the Hamiltonian cycle minimizing the expected total cost.
These planning problems have been formulated as two-stage integer stochastic programs with recourse. Discretization methods are usually applied to approximate the probability distribution of the random parameters. The resulting approximated program becomes a deterministic linear program with integer decision variables of generally very large dimensions, beyond the reach of exact methods.
Therefore, heuristics are required. For the MHKPu, we apply the extreme value theory and derive a deterministic approximation, while for the SVCSBPP and the mpTSPs we introduce effective and accurate heuristics based on the progressive hedging (PH) ideas. The PH mitigates the computational difficulty associated with large problem instances by decomposing the stochastic program by scenario. When effective heuristic techniques exist for solving individual scenario, that is the case of the SVCSBPP and the mpTSPs, the PH further reduces the computational effort of solving scenario subproblems by means of a commercial solver. In particular, we propose a series of specific strategies to accelerate the search and efficiently address the symmetry of solutions, including an aggregated consensual solution, heuristic penalty adjustments, and a bundle fixing technique. Yet, although solution methods become more powerful, combinatorial problems in the CL context are very large and difficult to solve. Thus, in order to significantly enhance the computational efficiency, these heuristics implement parallel schemes.
With the aim to make a complete analysis of the problems proposed, we perform extensive numerical experiments on a large set of instances of various dimensions, including realistic setting derived by real applications in the urban area, and combinations of different levels of variability and correlations in the stochastic parameters. The campaign includes the assessment of the efficiency of the meta-heuristic, the evaluation of the interest to explicitly consider uncertainty, an analysis of the impact of problem characteristics, the structure of solutions, as well as an evaluation of the robustness of the solutions when used as decision tool. The numerical analysis indicates that the stochastic programs have significant effects in terms of both the economic impact (e.g. cost reduction) and the operations management (e.g. prediction of the capacity needed by the firm). The proposed methodologies outperform the use of commercial solvers, also when small-size instances are considered. In fact, they find good solutions in manageable computing time. This makes these heuristics a strategic tool that can be incorporated in larger decision support systems for CL.
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Isolan, Ilaria. "Environmental economics models for efficient and sustainable logistics systems." Doctoral thesis, Università degli studi di Padova, 2019. http://hdl.handle.net/11577/3427294.
Full textAbstract:
The Intergovernmental Panel on Climate Change (IPCC) reports that global warming poses a grave threat to the world’s ecological system and the human race. This phenomenon is very likely caused by increasing concentrations of carbon emissions, which mainly results from such human activities as fossil fuel burning and deforestation (IPCC, 2007). A powerful action is required to stabilize the rising temperatures, involving many countries with a common objective. As asserted by Stavins (2008), without an effective global climate agreement no result will be accomplished.
In order to mitigate global warming, the United Nations (UN), the European Union (EU), and many countries have introduced some policies and mechanisms to contain the total amount of greenhouse gas emissions. Among these, one of the primary legislations is the European Union Emission Trading System (EU-ETS). On the contrary, other nations still consider the efforts to mitigate global warming as obstacles to striving for economic growth. Therefore, without a comprehensive engagement, some actors are advantaged and more competitive in the global economy. Some others, involved in emission saving policies, have to face stronger investments and restrictions, with the risk of suffering economic disadvantages.
Since the emissions released by companies’ operational activities into the air are one of the main causes of global climate change (He et al. 2015), businesses are becoming increasingly conscious of their carbon footprint and have begun to incorporate environmental thinking into their business strategy and supply chain management.
In order to help managers driving companies towards sustainable and efficient purchasing decisions, in this research work the Sustainable Economic Order Quantity (S-EOQ) Model introduced by Battini et al. (2014) is improved by developing a bi-objective lot-sizing model with two different objective functions to minimize (costs and emissions) and integrating the Cap and Trade regulatory policy (characteristic of the EU-ETS). This S-EOQ model is useful in practice to support managers in understanding the Pareto frontier shape linked to a specific purchasing problem, defining the cost-optimal and emission-optimal solutions and identifying a sustainable quantity to purchase when a Cap and Trade mitigation policy is present.
The model behavior is analyzed according to variation in the market carbon price and it is analytically demonstrated that today carbon prices are still far too low to motivate managers towards sustainable purchasing choices.
Moreover, two innovative bi-objective Sustainable Joint Economic Lot Size (S-JELS) Models under a Cap and Trade policy are introduced (applying the Cap and Trade regulation only to the buyer or to both buyer and supplier), in order to consider costs and emissions related to a two-echelon supply chain, not only to the buyer. By considering two different objective functions to minimize (costs and emissions), both economic and sustainable issues are equally considered and integrated in the contest of a supply chain. In this way, the models lead the Decision Makers to more sustainable and efficient logistic and purchasing solutions, considering a supply chain point of view. With the purpose of helping companies analyzing the trade-offs among different supplies, the S-JELS models can be run iteratively for many sourcing options, in order to build the Pareto frontiers for each supplier and compare then the frontier shapes, the cost-optimal solutions and the emission-optimal ones.
One of the two S-JELS models presented (the one with Cap and Trade regulation applied only to the buyer) is then integrated into a procedure for assessing a Sustainable Supplier Selection. The objective is to provide the managers with numerical KPI and user-friendly graphs, in order to help them on analysing the trade-offs among different supplies and on evaluating the selection criteria for each potential supplier in an easier, faster, analytical and correct way.
In the end, it is presented a case study from the manufacturing industry. The objective is to help managers on carrying out a Sustainable Supplier Selection between a Domestic and a Far East sourcing, by applying the S-JELS model integrated in an AHP supplier selection procedure. The model is exploited in order to provide the Decision Makers (DMs) with the tools for selecting the best sourcing option for their company. The DMs by iterating the solution process can obtain and compare different Pareto frontiers, being able to consider trade-offs before taking a purchasing strategy decision.<br>Secondo l’Intergovernmental Panel on Climate Change (IPCC), il riscaldamento globale rappresenta una grave minaccia per il sistema ecologico mondiale e quindi anche per l’umanità. Questo fenomeno è causato in gran parte dall'aumento di emissioni di CO2, derivanti principalmente da attività umane come la combustione fossile e la deforestazione (IPCC, 2007). Risulta quindi necessaria una decisa azione per stabilizzare le temperature in aumento, tale da coinvolgere molti Paesi per il raggiungimento di un obiettivo comune; come sostenuto da Stavins (2008), senza un efficace accordo globale non sarà possibile raggiungere alcun risultato.
Al fine di mitigare il riscaldamento globale, le Nazioni Unite (ONU), l'Unione Europea (UE) e molti altri Paesi hanno introdotto politiche e meccanismi per contenere la quantità totale di emissioni di gas serra. Tra questi, una delle normative più rilevanti è l’European Union Emission Trading System (EU-ETS).
Altre Nazioni, al contrario, considerano gli sforzi per mitigare il global warming un ostacolo alla loro crescita economica e risultano quindi avvantaggiate e più competitive rispetto a quei Paesi coinvolti in politiche per la riduzione delle emissioni.
Dato che le emissioni rilasciate nell’aria dalle attività operative delle imprese sono una delle principali cause del cambiamento climatico globale (He et al., 2015), le aziende stanno prendendo consapevolezza del loro impatto ambientale e iniziano a seguire una filosofia più sostenibile sia a livello di strategia aziendale, che di gestione della supply chain.
In questo lavoro di ricerca, il Sustainable Economic Order Quantity (S-EOQ) Model introdotto da Battini et al. (2014) viene perfezionato, al fine di aiutare i manager a guidare le aziende verso decisioni di acquisto sostenibili ed efficienti. Si sviluppa un modello di dimensionamento del lotto con due diverse funzioni obiettivo da minimizzare (costi ed emissioni), inoltre viene integrata la politica di regolamentazione Cap and Trade, caratteristica dell’EU-ETS. Questo modello S-EOQ risulta utile per varie ragioni: comprendere la forma della di frontiera di Pareto associata ad uno specifico problema di acquisto; definire le soluzioni ottimali in termini di costi e di emissioni; identificare una quantità sostenibile di acquisto quando è presente una politica di Cap and Trade delle emissioni.
Il comportamento del modello viene analizzato in relazione alla variazione del prezzo delle emissioni di carbonio, dimostrando analiticamente che i prezzi attuali sono ancora troppo bassi per motivare i manager verso scelte di acquisto sostenibili.
Inoltre, vengono introdotti due Sustainable Joint Economic Lot Size (S-JELS) Models nell'ambito di una politica di Cap and Trade (applicando la regolamentazione solo al buyer o sia al buyer che al supplier), in modo da considerare i costi e le emissioni relativi ad una catena di fornitura, non solo al buyer. Considerando due differenti funzioni obiettivo da minimizzare (i costi e le emissioni), le problematiche economiche e sostenibili sono ugualmente tenute in considerazione e integrate nel contesto di una supply chain. In questo modo, i modelli supportano i manager nel prendere decisioni logistiche e di acquisto più sostenibili ed efficienti, considerando il punto di vista della supply chain. Con lo scopo di aiutare le aziende ad analizzare i trade-off tra diverse forniture, i modelli S-JELS possono essere eseguiti iterativamente per varie opzioni di sourcing, al fine di costruire le frontiere di Pareto per ciascun fornitore e confrontare quindi le forme della frontiera, le soluzioni ottimali in termini di costi e in termini di emissioni.
Uno dei due modelli S-JELS presentati (quello in cui la politica di Cap and Trade è applicata solo al buyer) viene inoltre integrato in una procedura per effettuare una Sustainable Supplier Selection. L'obiettivo è fornire ai decisori KPI numerici e grafici user-friendly, al fine di aiutarli ad analizzare i trade-off tra le diverse opzioni di fornitura e valutare quindi i criteri di selezione per ogni potenziale fornitore in modo più semplice, rapido, analitico e corretto.
Infine, viene presentato un caso studio del settore manifatturiero. L'obiettivo è quello di aiutare i manager a condurre una Sustainable Supplier Selection tra un fornitore Nazionale ed uno collocato nel Far East, applicando il modello S-JELS, integrato in una procedura AHP per la selezione dei fornitori. Tale modello viene dunque impiegato per fornire ai Decision Makers (DMs) gli strumenti per selezionare la migliore opzione di approvvigionamento aziendale. I DMs, iterando il modello, possono ottenere e confrontare diverse frontiere di Pareto, valutando così i trade-off prima di prendere una decisione in merito alla strategia di acquisto.
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SGARBOSSA, FABIO. "MODELS FOR EFFICIENCY OPTIMIZATION OF INDUSTRIAL PLANTS AND LOGISTICS." Doctoral thesis, Università degli studi di Padova, 2010. http://hdl.handle.net/11577/3426885.
Full textAbstract:
In the last decades, the global markets have driven the manufacturing and service companies to be more flexible and efficient as for goods and services operations are concerned. More attention has also been paid to the performance of productive and logistic systems. In fact, the strict relation between flexibility and competitiveness of companies and efficiency of their productive plants and logistics is well known.
It is important to define, monitor and improve the efficiency of industrial and logistic systems. Many definitions of efficiency have been introduced and the most important is the Overall Equipment Efficiency (OEE), introduced by Nakajima at the end of the ‘80s. This index quickly spread in many industrial fields and it connects the efficiency of productive and logistic systems to three main factors: the availability of systems, the quality of produced goods/services and the productive and logistics performance.
Between these factors, more attention has been paid to the parameter related to the availability of systems. Moreover, it is known that the availability is strictly linked to the survival behavior of systems.
In this field, the manuscript introduces several innovative theoretical models for the survival analysis of components and productive-logistics complex systems, with particular attention to the systems which operate in different operative conditions.
This thesis is structured in the following main parts:
1. Introduction of most important models of OEE and their relationship with availability of productive and logistic systems;
2. Discussion about the relation between survival behavior and operative conditions;
3. Definition and development of innovative theoretical models for the system reliability modeling and their validation thanks to several industrial applications;
4. Definition and development of innovative maintenance policies for the efficiency improvement, based on the extension of scientific literature, thanks to the theoretical models introduced in previous parts;
5. Definition of innovative model for the performance analysis of logistic systems, in particular for Automated Storage/Retrieval Systems and comparison with the existing models.
The research has also been carried out in collaboration with Prof. Hoang Pham, director of Department of Industrial and Systems Engineering, Rutgers University, Piscataway – New Jersey (USA), during a period the author spent as “visiting researcher” in the Quality and Reliability Engineering Laboratory of that department.
The present work has carried out to the publishing of several scientific contributions in relevant International Journals and Conferences, like International Journal of Mathematics in Operational Research, International Journal of System Science and IEEE Transactions on Man, Cybernetics and Systems.<br>Negli ultimi decenni, il mercato ha portato le aziende manifatturiere e di servizi ad essere più flessibili e efficienti nella produzione dei propri beni e servizi. Maggior attenzione è stata quindi posta nei confronti delle performance dei sistemi produttivi-logistici. É infatti noto lo stretto legame tra flessibilità e competitività delle aziende con l’efficienza degli impianti produttivi e della logistica caratterizzanti le stesse.
É importante quindi riuscire a definire, monitorare e migliorare l’efficienza degli impianti industriali e dei sistemi logistici. Sono stati introdotte numerose definizioni di efficienza, tra le quali la più importante è l’Overall Equipment Efficiency (OEE), introdotta alla fine degli anni ’80 da Nakajima. Tale indice si è presto diffuso in numerosi settori e lega l’efficienza dei sistemi produttivi e logistici a tre fattori principali: la disponibilità dei sistemi, la qualità dei beni/servizi e le performance produttive e logistiche.
Tra questi fattori, maggior attenzione è stata posta al parametro relativo alla disponibilità dei sistemi. Inoltre è noto come la disponibilità dei sistemi sia strettamente legata al comportamento affidabilistico dei sistemi stessi.
Su tale fronte, questo elaborato introduce innovativi modelli teorici per l’analisi dell’affidabilità e disponibilità di componente e sistemi logistico-produttivi, con particolare attenzione ai sistemi soggetti a diverse condizioni operative.
La tesi si articola in tali principali parti:
1. Introduzione ai principali modelli di OEE e loro legame con la disponibilità dei sistemi logistico-produttivi;
2. Discussione del legame stretto tra comportamento affidabilistico e condizioni ambientali;
3. Sviluppo di modelli teorici innovativi per la modellazione delle caratteristiche affidabilistiche e loro validazione tramite applicazioni industriali;
4. Definizione e sviluppo di nuove politiche manutentive basate sull’estensione della letteratura scientifica grazie ai modelli teorici precedentemente verificati, per il miglioramento degli indici di efficienza;
5. Definizione di un nuovo modello per l’analisi delle performance di sistemi logistici quali gli Automated Storage/Retrieval Systems e comparazione con i modelli esistenti in letteratura.
Il lavoro di tesi è stato sviluppato in stretta collaborazione anche con il Prof. Hoang Pham, direttore del Department of Industrial and Systems Engineering, Rutgers University, Piscataway – New Jersey (USA), grazie ad un periodo di ricerca di alcuni mesi svolto dall’autore presso Quality and Reliability Engineering Laboratory di tale dipartimento.
Il presente lavoro ha portato anche alla pubblicazione di diversi contributi su importanti riviste e convegni internazionali, quali International Journal of Mathematics in Operational Research, International Journal of System Science e IEEE Transactions on Man, Cybernetics and Systems.
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Pan, Li, and 潘莉. "Mathematical modeling for warehouse logistics: stock loading and order picking." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2012. http://hub.hku.hk/bib/B4784940X.
Full textAbstract:
Logistics makes extensive use of human and material resources to achieve a
target level of customer service at the lowest possible cost. It has been recognized
as a major key to success in commerce and industry, and continues to
evolve radically and grow in importance in recent years. Warehousing, as one
of the most costly elements of logistics, is often the central operation in most
logistics networks. Its successful management is critical in terms of both cost
and service. In this thesis, two problem areas in warehouse logistics are studied:
stock loading and order picking.
Stock loading is an essential operation in modern logistics. Improvement on
container capacity utilization and loading efficiency significantly reduces costs.
For a given set of boxes in different sizes and an unlimited number of identical
containers, the basic cargo loading problem is to determine the minimum
number of containers required. The problem is proven NP-hard. To tackle this
problem, a Tabu search optimization with a tree-based cargo loading algorithm
as its inner heuristic is proposed. This approach has flexibility in taking different
box conditions into consideration, and can find better solutions on average
than other recent meta- or heuristic algorithms.
Decreasing order sizes and increasing fuel costs provide a strong incentive for
the inner-city truck loading operation to utilize container space more efficiently
in transporting goods to multiple clients during one trip. This considers not
only traditional loading constraints, but also multi-drop requirements. A wallbuilding
heuristics based on a binary tree data structure is proposed to handle
these side constraints. A dynamic space decomposition approach, together with
a repacking and space amalgamation strategy, permits an efficient and effective
loading plan.
Order picking, one of the most critical warehousing operations, is the second
problem studied in this thesis. An analytical approximation model is proposed
based on probability modeling and queueing network theory applied to a synchronized
zone picker-to-part order picking system with different routing and
ABC-class inventory storage policies. The numerical results are compared and
validated via simulation. The resulting model can therefore be usefully applied
in the design and selection process of order picking systems.
The routing versus storage issues are further investigated with a simulation
model. This extends the existing research by evaluating multiple routing and
storage policies under varying operating conditions. Results show that the midpoint,
return and traversal routing policies generally perform best when paired
with perimeter, across-aisle and within-aisle storage strategies, respectively. Yet
performance is indeed dependent on demand patterns, zone sizes, batch sizes
and order sizes.
At first glance, order picking and stock loading operation seem to pursue
different objectives. However, they are two related operations conducted sequentially
from internal to the outbound side of warehousing. An efficient
order picking system is a precondition for an effective loading operation at the
shipping dock, especially when multiple orders need to be selected for consolidation
in shipment. The proposed loading algorithms and the order picking
system performance evaluation models can be used to further study the effective
integration of these two functions.<br>published_or_final_version<br>Mathematics<br>Doctoral<br>Doctor of Philosophy
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Tumaš, Natalja. "Logistinis (ribinis) kapitalo kaupimo modelis Lietuvos bankų sistemoje." Master's thesis, Lithuanian Academic Libraries Network (LABT), 2014. http://vddb.library.lt/obj/LT-eLABa-0001:E.02~2008~D_20140623_183535-34644.
Full textAbstract:
Tiriant kapitalo kitimą, dažniausiai remiamasi eksponentiniu kitimo dėsniu, tačiau toks kapitalo vertinimas nėra tikslus uždaroms, turinčioms ribotus išteklius sistemoms. Darbe sprendžiama kapitalo kitimo modeliavimo logistiniais modeliais problema. Šių modelių taikymas kapitalui yra praktiškai netyrinėtas. Tiriamo darbo objektas yra Lietuvos bankų sistemos kapitalas, tiriamas matematinės analizės metodais. Kadangi logistinis kapitalo kaupimo modelis galioja tik uždaroje sistemoje, todėl uždara sistema yra laikoma Lietuvos bankų sistema. Tyrimo tikslas - pritaikyti eksponentinį ir logistinį kapitalo kaupimo modelius, kapitalo augimui prognozuoti. Taip pat pritaikyti logistinį (ribinį) kapitalo kaupimo modelį Lietuvos bankų sistemoje, nustatant kapitalo kitimo tendencijas bei maksimalią kapitalo ribą. Darbas susideda iš trijų pagrindinių dalių. Pirmoje dalyje išnagrinėta Lietuvos bankų sistema, pateikti statistiniai duomenys apie Lietuvos komercinių bankų veiklą (kapitalas (aktyvai), akcinis kapitalas, akcininkų nuosavybė), kad būtų galima atlikti skaičiavimus remiantis eksponentiniu bei logistiniu kapitalo kaupimo modeliu; Antroje dalyje išnagrinėti eksponentinis ir logistinis kapitalo kaupimo modeliai; Trečioje dalyje yra atliekami tyrimai, kuriais patvirtinama darbo hipotezė, kad logistinis kapitalo kaupimo modelis yra tinkamas nustatyti kapitalo kaupimo tendencijas bei apskaičiuoti maksimalią kapitalo ribą Lietuvos bankų sistemoje. Pateikiami grafikai. Darbo apimtis – 78... [toliau žr. visą tekstą]<br>The main objective of the graduation paper is to use the logistic (marginal) model of capital accumultaion to the Lithuanian banking system. Particularly goals are to analyze Lithuanian banking system; analyze exponential growth model; analyze the logistic (marginal) model of capital accumulation; compare these models; perform the experimental research using exponential growth model and logistic (marginal) model of capital accumulation; evaluate the change tendencies of capital and maximal boundaries of growth in Lithuanian banking system; supply the empirical research conclusions. The analysis of the models of accumulation las lead to the conclusion that the logistic model allow for the modelling of development of the populations whose growth is limited by the insufficiency of resources. The logistic model of capital accumultation reflect the dynamics of the population's (capital's) growth more precisely. In the application of the logistic model of capital accumulation, the determination of the regression coefficients comes to be one of the most important and problematic tasks.
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Silva, Carlos Patricio Montenegro. "Inferência bayesiana em modelos de dinâmica de populações biológicas com termo de perturbação assimétrico." Universidade de São Paulo, 2016. http://www.teses.usp.br/teses/disponiveis/45/45133/tde-15052016-104959/.
Full textAbstract:
Neste trabalho de tese, estudamos o modelo de crescimento logístico de populações biológicas utilizando a abordagem de espaço de estados. Os estados não observados são as biomassas anuais, a equação de observação é linear e a equação de estado é não linear. As distribuições de probabilidade utilizadas para os termos de erro de observação aditivos são: Normal, t-student, Skew-normal e Skew-t. As distribuições Log-normal, Log-t, Log-skew-normal e Log-skew-t são consideradas para os erros de observação multiplicativos. A inferência nos modelos é realizada considerando-se métodos Bayesianos e as distribuições a posterior de interesse são aproximadas utilizando-se algoritmos MCMC e a aproximação de Laplace. Apresentamos duas aplicações, a primeira referente a pesca de camarão marinho na costa do Chile, na qual a variável observável é o rendimento médio anual de pesca (captura por unidade de esforço média). Na segunda é considerada a pesca de lagostim vermelho na costa de Chile, na qual além do rendimento médio anual da pesca, observa-se as estimativas anuais de biomassa vulnerável, obtidas através de estudos de área varrida. Para o primeiro conjunto de dados, os modelos com erros de observação multiplicativos têm melhor performance, particularmente os modelos Log-skew-normal e Log-skew-t. Considerando estes resultados, no segundo caso utilizamos somente erros multiplicativos e a distribuição a posteriori preditiva mostra que cada variável observável parece ter sua própria família de distribuição de probabilidades. Além disso, os resultados também revelam uma crescente complexidade do modelo ao incorporar a classe mais geral de distribuições assimétricas.<br>We study the logistic population growth model using a state-space approach. The non observable states are the annual biomass of the population with a linear observation equation and a non-linear state equation. The probability distribution used for the additives observation error terms are Normal, Student-t, Skew-normal and Skew-t, and Log-normal, Log-t, Log-skew-normal and Log-skew-t for multiplicative observation errors terms. The inference about the parameters of the models is performed using Bayesian methods, with MCMC algorithms and Laplace approximations. We present two applications to real data sets. The first in marine shrimp population off the coast of Chile, where observable variable is the average annual fishing yield. The second application is for the population of the red squat lobster off Chile, where in addition to the average annual fishing yield, a second observable variable was included. In the first case, the multiplicative observational errors models presented the best results. Particularly the Log-skew-normal and Log-skew-t models has the better performances. Considering these results, in the second application we use only multiplicative observation errors models.
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Martins, Maria Cristina. "Análise de resíduos projetados em modelos não-lineares de regressão: uma aplicação em crescimento de frutos." Universidade de São Paulo, 2013. http://www.teses.usp.br/teses/disponiveis/11/11134/tde-19022013-171004/.
Full textAbstract:
Alguns aspectos devem ser considerados nos trabalhos com frutíferas como o ponto adequado de colheita e estratégias de conservação, sendo fundamental a análise do crescimento e desenvolvimento dos frutos. Vários tipos de modelos estatísticos podem descrever os processos de crescimento envolvidos no sistema de produção vegetal, sendo os modelos não lineares considerados mais adequados para esse tipo de estudo. Para que os resultados obtidos no ajuste do modelo sejam válidos é necessário verificar a qualidade de ajuste por meio de uma análise dos resíduos. A distribuição dos resíduos ordinários para os modelos de regressão não linear, é matematicamente trabalhosa e os critérios de diagnóstico são falhos, principalmente em pequenas amostras. Diante de tal fato, Cook e Tsai (1985) definiram o resíduo projetado. O comportamento dos resíduos projetados é melhor do que o dos resíduos ordinários, pois suas propriedades são mais próximas das correspondentes ao resíduo ordinário da regressão normal linear. O ganho é substancial se o teste para a medida de não linearidade for significativo. Por meio dos ajustes dos modelos logístico e de Gompertz aos dados de comprimento de peras foi realizada a análise dos resíduos ordinários e dos resíduos projetados, a fim de evidenciar suas vantagens. Os resíduos projetados se mostraram viáveis para diagnóstico dos modelos e descartaram possíveis tendências apresentadas pelos resíduos normalizados.<br>Some aspects must be considered in the works with fruit tree such as the appropriate point of harvest and conservation strategies, being fundamental the analysis of growth and fruit developments. Several types of statistical models can describe the growth processes involved in plant production system and the non-linear models are considered more suitable for this type of study. For the results obtained from the model fit to be valid is necessary to check the quality of fit through a residual analysis. The distribution of the ordinary residuals in the non-linear regression models is mathematically complicated and the diagnostic criteria are not precise, mainly in small samples. To overcome this fact, Cook and Tsai (1985) defined the projected residual. The behaviour of the projected residuals is better than the ordinary residuals since their properties are closer to those corresponding to the ordinary residuals for the normal linear regression. The gain is substantial if the test for non-linearity is significant. Through the fit of the logistic and Gompertz models to the pears length data, it was performed an analysis of the ordinary and projected residuals in order to demonstrate their advantages. The projected residuals showed more feasible for the diagnostic of the models and ruled out possible trends presented by normalized residuals.
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Harris, Sinclair M. "Comparison of three Combat Logistic Force models." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from the National Technical Information Service, 1989. http://edocs.nps.edu/npspubs/scholarly/theses/1989/Mar/89Mar_Harris.pdf.
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Webster, Gregg. "Bayesian logistic regression models for credit scoring." Thesis, Rhodes University, 2011. http://hdl.handle.net/10962/d1005538.
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The Bayesian approach to logistic regression modelling for credit scoring is useful when there are data quantity issues. Data quantity issues might occur when a bank is opening in a new location or there is change in the scoring procedure. Making use of prior information (available from the coefficients estimated on other data sets, or expert knowledge about the coefficients) a Bayesian approach is proposed to improve the credit scoring models. To achieve this, a data set is split into two sets, “old” data and “new” data. Priors are obtained from a model fitted on the “old” data. This model is assumed to be a scoring model used by a financial institution in the current location. The financial institution is then assumed to expand into a new economic location where there is limited data. The priors from the model on the “old” data are then combined in a Bayesian model with the “new” data to obtain a model which represents all the available information. The predictive performance of this Bayesian model is compared to a model which does not make use of any prior information. It is found that the use of relevant prior information improves the predictive performance when the size of the “new” data is small. As the size of the “new” data increases, the importance of including prior information decreases
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Wang, Jie. "Incorporating survey weights into logistic regression models." Digital WPI, 2013. https://digitalcommons.wpi.edu/etd-theses/267.
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Incorporating survey weights into likelihood-based analysis is a controversial issue because the sampling weights are not simply equal to the reciprocal of selection probabilities but they are adjusted for various characteristics such as age, race, etc. Some adjustments are based on nonresponses as well. This adjustment is accomplished using a combination of probability calculations. When we build a logistic regression model to predict categorical outcomes with survey data, the sampling weights should be considered if the sampling design does not give each individual an equal chance of being selected in the sample. We rescale these weights to sum to an equivalent sample size because the variance is too small with the original weights. These new weights are called the adjusted weights. The old method is to apply quasi-likelihood maximization to make estimation with the adjusted weights. We develop a new method based on the correct likelihood for logistic regression to include the adjusted weights. In the new method, the adjusted weights are further used to adjust for both covariates and intercepts. We explore the differences and similarities between the quasi-likelihood and the correct likelihood methods. We use both binary logistic regression model and multinomial logistic regression model to estimate parameters and apply the methods to body mass index data from the Third National Health and Nutrition Examination Survey. The results show some similarities and differences between the old and new methods in parameter estimates, standard errors and statistical p-values.
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Erdemir, Ugur. "Optimizing warehouse logistics operations through site selection models : Istanbul, Turkey." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2003. http://library.nps.navy.mil/uhtbin/hyperion-image/03Mar%5FErdemir.pdf.
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Phangestu, Jimmi. "Optimisation Models for Medium-Long Term Logistics Planning in Mining." Thesis, Curtin University, 2017. http://hdl.handle.net/20.500.11937/57345.
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In the mining industry, the logistics planning problem involves a mining value chain that comprises stockpiles at multiple mines, a rail network, stockpiles at multiple ports, and shipping. The objective is to maximise the total material throughput subject to a range of operational and capacity restrictions. We develop and implement an effective computational model for solving this difficult large-scale problem. Testing on real case studies demonstrates the value of our methodology.
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Cavagnini, Rossana. "Stochastic programming models for distribution logistics, bikesharing and production management." Doctoral thesis, Università degli studi di Bergamo, 2019. http://hdl.handle.net/10446/128677.
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In this thesis, we study four different problems, all characterized by the presence of uncertainty. The first two of them deal with a distribution system in which transshipment and/or backordering are allowed. For the first problem, we propose a two-stage stochastic program, we provide complexity results and we show that considering uncertainty explicitly in the model leads to better solutions with respect to the ones provided by the corresponding deterministic program, especially if limited recourse actions are admitted. For the second distribution problem, we propose a multi-stage stochastic model. As the complexity increases with the number of stages, we first derive optimal policies useful for solving two polynomially solvable cases. Then, for the general case, we show that the rolling horizon heuristic performs well by properly decomposing the time horizon. For the third problem, we derive a two-stage stochastic model to optimize the allocation and rebalancing activities in a bikesharing system. After showing the benefits of modeling uncertainty, we compare the solution of our stochastic program with the one obtained by Newsvendor model-based heuristics and with the real implemented system. For the fourth problem, we propose a two-stage stochastic programming model that quantifies the impact of worker assignment decisions to produce through an exponential stochastic learning curve. After linearizing it through a mixed integer program that can be solved efficiently, we perform a rigorously designed computational study and statistical analysis to derive tactics and managerial insights for how an organization should plan its production operations about assignment, cross-training and practicing. Finally, given the complexity of solving stochastic integer programs (even for the two-stage case), we propose a methodology in order to obtain monotonic chains of lower bounds for problems hard to be solved and we present some preliminary results based on instances from the literature.
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Liorenšaitytė, Vilma. "Logistikos sistemų formalus imitacinis modeliavimas." Master's thesis, Lithuanian Academic Libraries Network (LABT), 2007. http://vddb.library.lt/obj/LT-eLABa-0001:E.02~2007~D_20070816_142240-69166.
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Šiuo metu egzistuoja įvairiausių sudėtingų sistemų imitacinių modelių kūrimo technologijų ir priemonių. Šiame darbe aiškinama, kaip imitacinis modelis gali būti integruojamas į verslo valdymo sistemą. Taip pat įvertinama, kad verlo valdymo sistemos gali būti paskirstytos atskiruose kompanijose ar kompiutersiuose. Šiame darbe bus išanalizuota koncepcija, kaip apjungti atskirus imitacinius modelius. Išanalizuota modelių integravimo į informacinę sistemą technologija. Pateikiami gamybos ir paskirstymo imitacinių modelių matematiniai aprašai, naudojant DEVS(Discrete Event Simulation) ir PLA(Piece-Linear Aggregates) specifikacijų metodus.<br>At present, a large number of modeling and simulation techniques and tools have been developed to deal with complex business systems. In this paper, we concentrate on scenario illustrating, how simulation models can be integrated in to business management system. Different infrastructure forms are possible, because services may be implemented on single machine or distributed throughout several companies’ networks. In this paper a concept will be analyzed - how to combine different simulation models. The technology for involvement of simulation models in to information systems will be created. Also the problem of simulation model transformation in to program code will be solved. For model formalization we can use a method of Piece-Linear Aggregates (PLA) that belongs to the class of time automata model. PLA method is close to Discrete Event Simulation (DEVS) formalism, which is used to create wide purpose simulation models.
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Al-Khatib, S. F. S. "Strategic logistics outsourcing : integrated models for evaluating and selecting Logistics Service Providers (LSPs) : upstream/downstream supply chain comparison." Thesis, Liverpool John Moores University, 2015. http://researchonline.ljmu.ac.uk/4406/.
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This research aims to maximize the logistics outsourcing benefits through developing new hybrid models for evaluating and selecting Logistics Service Providers (LSPs). The growing demand for logistics outsourcing and the increase in the number and type of LSPs highlight the increasing importance of the LSP evaluation and selection process. Firms use various approaches to evaluate and select their LSP partners. Most of these approaches seem to have overlooked the strategic side of the logistics outsourcing process. Additionally, the uncertainty issue of data, the complexity of the decision and the large number of criteria involved increase the attractiveness of the Multi-Criteria Decision-Making (MCDM) approaches. A comparative literature review was used in order to identify crucial factors and methods that are used in logistics literature in fragmented ways and therefore, to establish and design a conceptual framework and models for logistics outsourcing. First, a long list of evaluation criteria was developed. Three main dimensions were identified: logistics performance, logistics resources and logistics services. Then a conceptual framework was developed using the three main dimensions with their related factors. Based on the comparative literature review outcomes, a number of integrated models have been developed and used to achieve this aim with emphasis given to FDEMATEL, FTOPSIS and FQFD techniques. Whereas the FDEMATEL technique contributed to construct influence relationships between factors under each dimension, develop impact-relationship maps and identify dependent and independent success factors (ISFs), the FTOPSIS technique used the weighted success factors to evaluate, rank and select the best LSP in three case studies. Twenty-one ISFs have been identified to be used in the final approach. These ISFs consist of eight LKPIs, seven logistics services and six logistics resources and capabilities. All of the factors were used to evaluate and select the best LSP alternative and ISFs were used to conduct the evaluation process. Different sensitivity analysis tests are used to confirm models’ robustness. Based on the outcomes of both cases, decision makers can use independent factors alone to evaluate and select the best LSP, which simplified the logistics outsourcing process in our study. The FQFD technique was used to link the LSUs strategic objectives with logistics requirements and the ISFs to develop a new strategic logistics outsourcing approach. Finally, two case studies representing the supply chain upstream and downstream are used to demonstrate the new hybrid approach effectiveness. The comparison of both cases’ findings highlighted their differences in terms of strategic objectives, logistics requirements and ISFs.
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Fachini, Juliana Betini. "Análise de influência local nos modelos de riscos múltiplos." Universidade de São Paulo, 2007. http://www.teses.usp.br/teses/disponiveis/11/11134/tde-02102007-085202/.
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Neste trabalho, é apresentado vários métodos de diagnóstico para modelos de riscos múltiplos. A vantagem desse modelo é sua flexibilidade em relação aos modelos de risco simples, como, os modelos Weibull e log-logístico, pois acomoda uma grande classe de funções de risco, função de risco não-monótona, por exemplo, forma de "banheira" e curvas multimodal. Alguns métodos de influência, assim como, a influência local, influência local total de um indivíduo são calculadas, analizadas e discutidas. Uma discussão computacional do método do afastamento da verossimilhança, bem como da curvatura normal em influência local são apresentados. Finalmente, um conjunto de dados reais é usado para ilustrar a teoria estudada. Uma análise de resíduo é aplicada para a seleção do modelo apropriado.<br>In this paperwork is present various diagnostic methods for polyhazard models. Polyhazard models are a flexible family for fitting lifetime data. Their main advantage over the single hazard models, such as the Weibull and the log-logistic models, is to include a large amount of nonmonotone hazard shapes, as bathtub and multimodal curves. Some influence methods, such as the local influence, total local influence of an individual are derived, analyzed and discussed. A discussion of the computation of the likelihood displacement as well as the normal curvature in the local influence method are presented. Finally, an example with real data is given for illustration. A residual analysis is performed in order to select an appropriate model.
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Tagliaferro, Elaine Pereira da Silva. "Avaliação de risco de carie dentaria : estado da arte e estudo longitudinal sobre preditores de risco em escolares." [s.n.], 2008. http://repositorio.unicamp.br/jspui/handle/REPOSIP/290311.
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Orientador: Antonio Carlos Pereira<br>Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba<br>Made available in DSpace on 2018-08-10T00:54:06Z (GMT). No. of bitstreams: 1
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Previous issue date: 2008<br>Resumo: A avaliação de risco de cárie é uma ferramenta importante na odontologia, uma vez que favorece o planejamento das ações em saúde com base em evidência científica. Esta tese, composta por dois estudos, teve como objetivos: a) apresentar uma visão geral e atual da avaliação de risco de cárie dentária (Capítulo 1); e b) determinar quais variáveis clínicas, comportamentais, socioeconômicas e demográficas identificaram indivíduos com maior probabilidade de desenvolver incremento de cárie, em estudo longitudinal realizado em um período de sete anos (Capítulo 2). No primeiro estudo, uma revisão da literatura odontológica sobre avaliação de risco de cárie nos últimos 10 anos foi realizada, a fim de identificar os fatores/preditores de risco da doença em crianças e adolescentes. Para isso, uma busca de artigos científicos publicados entre 1997 e 2007 foi conduzida na base de dados MEDLINE. Os estudos foram conduzidos principalmente com escolares (n= 19), seguidos pelas pesquisas realizadas em crianças em idade pré-escolar (n=l1), adolescentes (n=8) e crianças de até dois anos (n=5). A experiência de cárie, condição gengival, contagem microbiológica, hábitos de higiene oral, concentração de minerais no biofilme dental, exposição ao fluoreto, nível socioeconômico e educacional, características demográficas, antropométricas, bem como hábitos bucais, dietéticos e de escovação foram as variáveis estudadas. A experiência passada de cárie foi o preditor dç risco predominante em todas as faixas etárias pesquisadas. Outras variáveis como os hábitos dietéticos, incluindo o consumo de açúcar, e os de escovação também podem ajudar a identificar indivíduos de alto risco de cárie. No segundo estudo, 206 escolares de três escolas de Piracicaba, estado de São Paulo, foram examinados no baseline e após sete anos pelos mesmos cirurgiões-dentistas, previamente calibrados, sob luz natural, usando espelho e sonda e seguindo as recomendações da Organização Mundial da Saúde para levantamentos epidemiológicos em saúde bucal. Os examinadores coletaram dados sobre as seguintes variáveis clínicas: cárie dentária, fluorose, higiene oral e presença de selante. Adicionalmente, informações sobre nível socioeconômico, uso de fluoreto, acesso a serviços odontológicos, hábitos dietéticos e de higiene oral foram obtidas no baseline por meio de questionário semi-estruturado enviado aos pais. Para testar a associação entre o incremento de superficies cariadas, perdidas e obturadas (CPOS) e as variáveis independentes, uma análise univariada foi conduzida utilizando-se o teste de Qui-quadrado ou o Exato de Fisher. A regressão logística múltipla foi usada para obter estimativas de Odds Ratios (OR), seus intervalos de confiança (IC) ao nível de 95% e níveis de significância. O modelo de predição demonstrou que os escolares com experiência de cárie em dentes permanentes (OR=2,49; IC=1,02-6,04; p=0,04) ou em dentes decíduos (OR=2,29; IC=1,24-4,23; p=0,00l), bem como aqueles cuja escolaridade máxima da mãe era de oito anos de estudo (OR=1,88; IC=1,03-3,45; p=0,03) apresentaram probabilidades significativamente superiores de apresentar incremento de CPOS. Os resultados desta tese demonstraram que o nível educacional materno pode identificar os escolares com risco de desenvolver a doença e que as variáveis relacionadas à experiência passada de cárie continuam sendo o principal preditor de risco<br>Abstract: Caries risk assessment is an important tool for dentistry, because it may help planning health actions based on scientific evidences. This thesis, composed of two studies, aimed to a) present an overview of caries risk assessment (Chapter 1); and b) determine which clinical, behavioral, socioeconomic and demographic variables could identify children with higher probability of developing caries increment in a seven-year longitudinal study (Chapter 2). In the first study, a search of the published English language literature from 1997 to 2007 was made for articles that reported on caries risk assessment in the MEDLINE database. The studies were conducted mainly in schoolchildren (n=19), followed by preschool children (n=11), adolescents (n=8), and infants (n=5). Variables such as caries experience, gingival status, microbiological counts, oral hygiene, plaque mineral concentration, fluoride history, socioeconomic and educationallevel, demographic, anthropometrical, oral, dietary and toothbrushing habits were studied. Past caries experience has been the predominant predictor of caries risk in 0-18-years old subjects. Other predictors such as dietary habits, including sugar intake, and toothbrushing habits may also help to identify high-risk individuals. Variables related to caries experience continue to be the main predictor of caries incremento In the second study, two hundred and six children from three schools in Piracicaba, Brazil, were examined at baseline and after 7 years by the same calibrated dentists in an outdoor setting, under natural light, using a dental mirror and probe following the World Health Organization recommendations for oral health surveys. The examiners collected data on the following clinical variables: dental caries, fluorosis, oral hygiene and presence of sealant. Moreover, information on socioeconomic level, fluoride usage, dental service utilization, dietary and oral hygiene habits was also obtained at baseline by means of a semi-structured questionnaire sent to the parents. In order to evaluate the association between the decayed, filling and missed surfaces (DMFS) increment and independent variables, a univariate analysis was performed using the Chi-square or Fisher exact tests. The multivariate logistic regression was used to estimate the adjusted Odds Ratio (OR), their 95% confidence intervals (C I) and significance levels. The prediction model demonstrated that the schoolchildren with caries experience in permanent (OR=2.49; CI=1.02-6.04; p=0.04) or primary teeth (OR=2.29; CI=1.24-4.23; p=0.001), as well as those whose mothers' educational level was up to eight years of schooling (OR=1.88; CI=1.03-3.45; p=0.03) were more prone to have DMFS increment. The results of this thesis demonstrated that the educational leveI of mothers could identify the schoolchildren at risk of developing the disease and that variables related to past caries experience continue to be the main risk predictor<br>Doutorado<br>Saude Coletiva<br>Doutor em Odontologia
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Ling, Kwok-tung, and 凌國棟. "Evolutionary optimisation of decision rules for production-distribution systems." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2003. http://hub.hku.hk/bib/B3124449X.
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Huang, Ximin, and 黄曦敏. "Mathematical models for coordination in supply chain management." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2011. http://hub.hku.hk/bib/B46604856.
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Čejková, Tereza. "Aplikace modelů diskrétní volby." Master's thesis, Vysoká škola ekonomická v Praze, 2008. http://www.nusl.cz/ntk/nusl-10520.
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This thesis treats with the theory, interpretation and application of the Discrete Choice Models. The theoretical part contains the Fitting the Logistic Regression Model, Testing for the Significance of the Coefficients, Testing for the Significance of the Model. The Multiple Logistic Regression is mentioned too. The model was applied to interview data from the International research called Reflex.
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Palaikytė, Rasa. "Logistiniai kapitalo kaupimo modeliai: gamybos (KOBB-DOUGLAS) funkcijos tyrimai." Master's thesis, Lithuanian Academic Libraries Network (LABT), 2014. http://vddb.library.lt/obj/LT-eLABa-0001:E.02~2008~D_20140623_183248-42068.
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Darbo tikslas – apžvelgus gamybos funkciją ir išnagrinėjus Cobb-Douglas gamybos funkciją sudaryti logistinį Cobb-Douglas gamybos funkcijos modelį panaudojant logistines funkcijas darbo ir kapitalo įvertinimui. Siekiant užsibrėžto tikslo, yra sprendžiami tokie uždaviniai: Apžvelgti gamybos funkciją ir jos savybes; Aprašyti Cobb-Douglas gamybos funkciją; Aprašyti logistines kapitalo kaupimo funkcijas; Pasiūlyti metodą gamybos išeigai skaičiuoti remiantis kapitalo ir darbo įeiga; Išanalizavus Cobb-Douglas gamybos funkcijos sudarymo principą ir pritaikius logistines funkcijas sudaryti gamybos funkcijos modelį 1899-1922 metų gamybos išeigai įvertinti. Nustatyti logistinės Cobb-Douglas gamybos funkcijos parametrus, kuriuos naudojant būtų galima rasti gamybos išeigą bei pateikti jų grafinį atvaizdavimą; Palyginti paprastos Cobb-Douglas funkcijos ir logistinės funkcijos modelio galimybes įvertinti gamybos išeigą 1899-1922 metais; Darbą sudaro pradiniai puslapiai, įvadas, analitinis skyrius, siūlomo sprendimo skyrius, eksperimentinis skyrius, išvados ir baigiamieji puslapiai. Pirmoje dalyje analizuojama gamyba, gamybos funkcija, jos savybės, Cobb-Douglas gamybos funkcija ir logistinės kapitalo kaupimo funkcijos. Antroje dalyje apibrėžiamas siūlomas sprendimas – logistinis Cobb-Douglas gamybos funkcijos modelis. Trečioje dalyje atliekamas logistinio Cobb-Douglas modelio sudarymas, skaičiuojami funkcijos parametrai, braižomi grafikai. Išvadose išdėstomi gauti rezultatai, kurių buvo... [toliau žr. visą tekstą]<br>The aim of the work is to analyze production function, Cobb-Douglas production function and create logistic Cobb-Douglas production function model using logistic functions for labour and capital evaluating. The main tasks are to review production function and its features, analyze Cobb-Douglas function and logistic capital accumulation models. After analysing Cobb-Douglas production function and logistic accumulation models propose logistic Cobb-Douglas production function model. Measure the coefficients of this model, and use it to calculate USA production output in 1899 -1922.Compare the possibilities of Cobb-Douglas production function and logistic Cobb-Douglas production function model to calculate production output. The methods used in the work are the following: general identification method, comparison, deduction, designing, analysis of alternatives, analysis of documents, synthesis, generalization, conversation methods, observation. Results – after analysing Cobb-Douglas production function and logistic capital accumulation models the logistic Cobb-Douglas production function model was created. It outlines the trend of USA production output in 1899 – 1922. It is better than simple Cobb-Douglas production function, because there is no need to find the values of labour and capital every year, because it is very difficult to measure these values. Also the logistic Cobb-Douglas production function model was created by using logistic accumulation recurrent relations... [to full text]
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Roberts, Brook R. "Measuring NAVSPASUR sensor performance using logistic regression models." Thesis, Monterey, California. Naval Postgraduate School, 1992. http://hdl.handle.net/10945/23952.
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Weng, Yu. "Maximum Likelihood Estimation of Logistic Sinusoidal Regression Models." Thesis, University of North Texas, 2013. https://digital.library.unt.edu/ark:/67531/metadc407796/.
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We consider the problem of maximum likelihood estimation of logistic sinusoidal regression models and develop some asymptotic theory including the consistency and joint rates of convergence for the maximum likelihood estimators. The key techniques build upon a synthesis of the results of Walker and Song and Li for the widely studied sinusoidal regression model and on making a connection to a result of Radchenko. Monte Carlo simulations are also presented to demonstrate the finite-sample performance of the estimators
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Richmond, James Howard. "Bayesian Logistic Regression Models for Software Fault Localization." Case Western Reserve University School of Graduate Studies / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=case1326658577.
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Joel, Teo Sze Ern. "EVALUATION OF CITY LOGISTICS SCHEMES WITH MULTI-AGENT SYSTEMS LEARNING MODELS." 京都大学 (Kyoto University), 2012. http://hdl.handle.net/2433/160991.
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Yu, Shaohua. "Optimization models and methods for tour planning in smart urban logistics." Thesis, université Paris-Saclay, 2020. http://www.theses.fr/2020UPAST045.
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La distribution urbaine désigne les activités de distribution de marchandises desservant les zones urbaines et les banlieues. Les progrès technologiques récents dans le domaine de la distribution sans personnel, ainsi que les nouvelles réglementations limitant l’utilisation des véhicules à moteur à combustion, vont modifier de manière significative la distribution urbaine de marchandises. En outre, le nouveau modèle commercial du commerce électronique apporte également de nouvelles opportunités et de nouveaux défis à la distribution urbaine de marchandises. Cette thèse se concentre sur un nouveau système de distribution visant à fournir de meilleurs services pour la distribution logistique urbaine. Nous allons tout d’abord étudier un système de livraison urbaine robotisé basé sur un fourgon qui peut transporter plusieurs robots, ce qui rend le système de distribution plus flexible et efficace. Ensuite, nous proposons d’intégrer la technologie de recharge en route et de recharge inverse dans le système de livraison urbaine robotisée par camionnette dans les opérations logistiques, afin d’économiser le temps pendant lequel les camionnettes électriques transportent les robots pour les recharger, ce qui augmente l’efficacité des systèmes de distribution. Enfin, nous incorporons les ramassages hybrides et les opérations de livraison dans le système de distribution urbaine robotisée basés sur des fourgons pour nous adapter au nouveau modèle commercial des entreprises de commerce électronique<br>Urban distribution refers to the distribution activities of goods serving urban areas and suburbs. Recent technological advances in unmanned distribution field, as well as new regulations limiting the use of combustion engine vehicles, will significantly change urban goods distribution. Besides, the new ecommerce business model also brings new opportunities and challenges to urban goods distribution. This thesis focuses on a novel distribution system to provide better services for urban logistics distribution. We first study a van-based robot urban delivery system and allow a van can carry multiple robot to make the distribution system more flexible. Then we incorporate en-route charging, and reverse charging technology into the van-based robot urban delivery system in logistics operations, to effectively use the time during which electric vans are carrying robots to recharge the robots, thereby increasing distribution systems’ efficiency. Finally, we incorporate hybrid pickup and delivery operations into the van-based robot urban distribution system to adapt to the new business model of e-commerce enterprises