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Junior, Márcio Fernando Stabile. "Melhorando o desempenho de agentes BDI Jason através de filtros de percepção." Universidade de São Paulo, 2015. http://www.teses.usp.br/teses/disponiveis/45/45134/tde-05022016-160602/.
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Um dos problemas do paradigma BDI quando se integram agentes a ambientes virtuais ou simuladores é a ausência de controle sobre as suas percepções. Não havendo alguma forma de percepção direcionada ao objetivo, o agente pode ser inundado por informações irrelevantes causando um aumento injustificado do tempo de processamento. Com o objetivo de fornecer um maior controle sobre as percepções do agente e reduzir o seu tempo de resposta, este trabalho apresenta um mecanismo de filtragem das percepções para o interpretador Jason que visa eliminar aquelas percepções que podem ser ignoradas. Para tal, foram propostos e implementados alguns tipos de filtros pré-definidos, que foram aplicados a três cenários diferentes. Através de validações estatísticas apropriadas, mostrou-se que a aplicação de filtros de percepção pode reduzir em até 80% o tempo de processamento de um agente, sem afetar significativamente o seu desempenho medido em termos de sua função de utilidade.When agents are supposed to be integrated to virtual environments virtual or simulators, one of the BDI paradigms major concerns is the lack of control over the agents perceptions. Without having any form of goal directed perceptions, the agent may be flooded by irrelevant information thus causing an unjustified increase in processing time. In order to provide greater control on the agents perceptions and to reduce its time response, this work presents a filtering perception mechanism for the Jason interpreter, aimed at eliminating those perceptions that can be ignored. To this end, some types of pre-defined filters have been proposed, implemented, and applied to three different scenarios. Through appropriate statistical validation methods, it was shown that applying perception filters can reduce up to 80 % of an agents processing time, without significantly affecting its performance measured in terms of its utility function.
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Mora, Michael da Costa. "Um Modelo formal e executável de agentes BDI." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 1999. http://hdl.handle.net/10183/3955.
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Modelos BDI (ou seja, modelos Beliefs-Desires-Intentions models) de agentes têm sido utilizados já há algum tempo. O objetivo destes modelos é permitir a caracterização de agentes utilizando noções antropomórficas, tais como estados mentais e ações. Usualmente, estas noções e suas propriedades são formalmente definidas utilizandos formalismos lógicos que permitem aos teóricos analisar, especificar e verificar agentes racionais. No entanto, apesar de diversos sistemas já terem sido desenvolvidos baseados nestes modelos, é geralmente aceito que existe uma distância significativa entre esta lógicas BDI poderosas e sistemas reais. Este trabalho defende que a principal razão para a existência desta distância é que os formalismos lógicos utilizados para definir os modelos de agentes não possuem uma semântica operacional que os suporte. Por “semântica operacional” entende-se tanto procedimentos de prova que sejam corretos e completos em relação à semântica da lógica, bem como mecanismos que realizem os diferentes tipos de raciocínio necessários para se modelar agentes. Há, pelo menos, duas abordagens que podem ser utilizadas para superar esta limitação dos modelos BDI. Uma é estender as lógicas BDI existentes com a semântica operacional apropriada de maneira que as teorias de agentes se tornem computacionais. Isto pode ser alcançado através da definição daqueles procedimentos de prova para as lógicas usadas na definição dos estados mentais. A outra abordagem é definir os modelos BDI utilizando formalismos lógicos apropriados que sejam, ao mesmo tempo, suficientemente poderosos para representar estados mentais e que possuam procedimentos operacionais que permitam a utilizaçao da lógica como um formalismo para representação do conhecimento, ao se construir os agentes. Esta é a abordagem seguida neste trabalho. Assim, o propósito deste trabalho é apresentar um modelo BDI que, além de ser um modelo formal de agente, seja também adequado para ser utilizado para implementar agentes. Ao invés de definir um novo formalismo lógico, ou de estender um formalismo existente com uma semântica operacional, define-se as noções de crenças, desejos e intenções utilizando um formalismo lógico que seja, ao mesmo tempo, formalmente bem-definido e computacional. O formalismo escolhido é a Programação em Lógica Estendida com Negação Explícita (ELP) com a semântica dada pelaWFSX (Well-Founded Semantics with Explicit Negation - Semântica Bem-Fundada com Negação Explícita). ELP com a WFSX (referida apenas por ELP daqui para frente) estende programas em lógica ditos normais com uma segunda negação, a negação explícita1. Esta extensão permite que informação negativa seja explicitamente representada (como uma crença que uma propriedade P não se verifica, que uma intenção I não deva se verificar) e aumenta a expressividade da linguagem. No entanto, quando se introduz informação negativa, pode ser necessário ter que se lidar com programas contraditórios. A ELP, além de fornecer os procedimentos de prova necessários para as teorias expressas na sua linguagem, também fornece um mecanismo para determinar como alterar minimamente o programa em lógica de forma a remover as possíveis contradições. O modelo aqui proposto se beneficia destas características fornecidas pelo formalismo lógico. Como é usual neste tipo de contexto, este trabalho foca na definição formal dos estados mentais em como o agente se comporta, dados tais estados mentais. Mas, constrastando com as abordagens até hoje utilizadas, o modelo apresentanto não é apenas uma especificação de agente, mas pode tanto ser executado de forma a verificar o comportamento de um agente real, como ser utilizado como mecanismo de raciocínio pelo agente durante sua execução. Para construir este modelo, parte-se da análise tradicional realizada na psicologia de senso comum, onde além de crenças e desejos, intenções também é considerada como um estado mental fundamental. Assim, inicialmente define-se estes três estados mentais e as relações estáticas entre eles, notadamente restrições sobre a consistência entre estes estados mentais. Em seguida, parte-se para a definição de aspectos dinâmicos dos estados mentais, especificamente como um agente escolhe estas intenções, e quando e como ele revisa estas intenções. Em resumo, o modelo resultante possui duas características fundamentais:(1) ele pode ser usado como um ambiente para a especificação de agentes, onde é possível definir formalmente agentes utilizando estados mentais, definir formalmente propriedades para os agentes e verificar se estas propriedades são satifeitas pelos agentes; e (2) também como ambientes para implementar agentes.
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Schmitz, Tiago Luiz. "Modelo anÃmico para raciocÃnio normativo organizacional de um agente BDI." reponame:Repositório Institucional da UFSC, 2016. https://repositorio.ufsc.br/xmlui/handle/123456789/162840.
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Tese (doutorado) - Universidade Federal de Santa Catarina, Centro Tecnológico, Programa de Pós-Graduação em Engenharia de Automação e Sistemas, Florianópolis, 2016.Made available in DSpace on 2016-05-24T17:55:52Z (GMT). No. of bitstreams: 1 339439.pdf: 2591225 bytes, checksum: 28846e10881c1ec7357d34d37a38f3c8 (MD5) Previous issue date: 2016
Em sistemas multiagentes abertos dotados de sistemas normativos é necessário que os agentes sejam capazes de deliberar sobre as normas do sistema e seus desejos pessoais. Considerando que os agentes normativos têm recursos limitados, é necessário raciocinar também sobre os recursos disponÃveis e se eles são suficientes para alcançar o objetivo implicado por uma norma. Nesta direção, o objetivo principal da tese é desenvolver uma arquitetura e um processo de raciocÃnio que juntos são capazes de deliberar sobre normas e desejos, levando em consideração os recursos finitos. Para atingir esse objetivo, o conceito de ânimo (THAYER, 1989) foi tomado como ponto de partida para propor uma arquitetura capaz de representar as informações necessárias para o agente deliberar sobre as normas e desejos. O processo de deliberação proposto mapeia essas informações em um problema de programação inteira mista e através de um solver obtém o conjunto de desejos e normas, que produz o melhor benefÃcio ao agente. Como cenário de aplicação dos conceitos estabelecidos nessa tese, foi desenvolvido o planejamento de trajetória on-line para um veÃculo aéreo não tripulado. Conferindo a este autonomia para deliberar sobre as rotas a serem percorridas. Os resultados obtidos nessa tese são: uma arquitetura de agente capaz de raciocinar sobre normas e desejos considerando recursos limitados e uma implementação da arquitetura proposta.
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Schmitz, Tiago Luiz. "Modelo anímico para raciocínio normativo organizacional de um agente BDI." reponame:Repositório Institucional da UFSC, 2016. https://repositorio.ufsc.br/xmlui/handle/123456789/168639.
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Tese (doutorado) - Universidade Federal de Santa Catarina, Centro Tecnológico, Programa de Pós-Graduação em Engenharia de Automação e Sistemas, Florianópolis, 2016.Made available in DSpace on 2016-09-27T04:03:27Z (GMT). No. of bitstreams: 1 339439.pdf: 2591225 bytes, checksum: 28846e10881c1ec7357d34d37a38f3c8 (MD5) Previous issue date: 2016
Em sistemas multiagentes abertos dotados de sistemas normativos é necessário que os agentes sejam capazes de deliberar sobre as normas do sistema e seus desejos pessoais. Considerando que os agentes normativos têm recursos limitados, é necessário raciocinar também sobre os recursos disponíveis e se eles são suficientes para alcançar o objetivo implicado por uma norma. Nesta direção, o objetivo principal da tese é desenvolver uma arquitetura e um processo de raciocínio que juntos são capazes de deliberar sobre normas e desejos, levando em consideração os recursos finitos. Para atingir esse objetivo, o conceito de ânimo (THAYER, 1989) foi tomado como ponto de partida para propor uma arquitetura capaz de representar as informações necessárias para o agente deliberar sobre as normas e desejos. O processo de deliberação proposto mapeia essas informações em um problema de programação inteira mista e através de um solver obtém o conjunto de desejos e normas, que produz o melhor benefício ao agente. Como cenário de aplicação dos conceitos estabelecidos nessa tese, foi desenvolvido o planejamento de trajetória on-line para um veículo aéreo não tripulado. Conferindo a este autonomia para deliberar sobre as rotas a serem percorridas. Os resultados obtidos nessa tese são: uma arquitetura de agente capaz de raciocinar sobre normas e desejos considerando recursos limitados e uma implementação da arquitetura proposta.
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Torres, Jorge Alberto Rangel. "Uma arquitetura para animar agentes autônomos em ambientes virtuais usando o modelo BDI." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2004. http://hdl.handle.net/10183/90427.
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Humanos virtuais são modelos computacionais de pessoas. Se necessário, podem apresentar uma aparência bastante realista, baseada em princípios fisiológicos e biomecânicos. Além disso, são capazes de comportar-se de forma autônoma e inteligente em ambientes dinâmicos, podendo apresentar até mesmo individualidade e personalidade. Humanos virtuais podem ser utilizados como atores sintéticos. Tais atores têm sido usados em uma série de aplicações com a finalidade de simular a presença de atores reais. A indústria de jogos por computador requer personagens que sejam capazes de reagir apropriadamente a eventos e circunstâncias inesperadas, e até mesmo de alterar o progresso do jogo com seus cursos de ação autônomos. Um modo natural para desenvolver tais personagens prevê o uso de técnicas de inteligência artificial, em particular aquelas relacionadas às áreas de agentes autônomos e sistemas multiagentes. Neste trabalho, propõese o uso do modelo BDI (Belief-Desire-Intention) para modelar agentes cognitivos, com a finalidade de implementar personagens animados. O modelo BDI é uma abordagem bastante conhecida e bem sucedida para o desenvolvimento de agentes autônomos em sistemas multiagentes. Trata-se de uma arquitetura poderosa para sistemas dinâmicos e complexos, nos quais agentes podem precisar agir sob informação incompleta e incorreta sobre o seu ambiente e os outros habitantes. Esta dissertação reúne um modelo articulado para animação de personagens, o qual requer a especificação de movimento em cada junta individualmente, e um interpretador para AgentSpeak(L), uma linguagem de programação orientada a agentes que implementa a arquitetura BDI. Foi desenvolvida uma interface que permite que o sistema de raciocínio de um agente, baseado em BDI, seja usado para dirigir o comportamento de um personagem em um sistema de animação. O uso de AgentSpeak(L) é uma abordagem promissora para a especificação em alto nível de animações complexas por computador. O modelo conceitual e sua implementação são apresentados em capítulos distintos. Esta separação visa simplificar a compreensão do modelo proposto, permitindo primeiro analisá-lo em um nível mais alto de abstração, para então verificar detalhes de programação. Este trabalho apresenta também duas animações 3D, usadas para ilustrar a abordagem proposta. A principal animação apresentada envolve um agente situado em um ambiente dinâmico; o agente continuamente percebe o ambiente e raciocina para determinar como agir sobre ele, baseado em seu estado mental BDI. A outra aplicação é bastante simples, mas útil para mostrar algumas questões que são relevantes para obter-se mais eficiência em programas AgentSpeak(L).Virtual humans are computational models of people. If necessary, they can portray a very realistic appearance, based on biomechanical and physiological principles. Besides, they are able to behave in an autonomous and intelligent way in dynamic environments, and even to exhibit individuality and personality. Virtual humans can be used as synthetic actors. Such kind of actors have been used in several applications, such as games, in order to simulate the presence of real actors. The computer-game industry requires characters that are able to react appropriately to unexpected events and circumstances, and even to change the game progress with their autonomous courses of actions. A natural way for developing such characters is by the use of artificial intelligence techniques, in particular those related to the areas of autonomous agents and multi-agent systems. In this work, the use of the Belief-Desire-Intention (BDI) model for cognitive agents in order to implement animated characters is proposed. The BDI model is a well-known and successful approach for the development of autonomous agents in multiagent systems. It is a very powerful architecture for dynamic and complex systems where agents may need to act under incomplete and incorrect information on other agents and their environment. This work brings together an articulated model for character animation, which requires the specification of motion on each joint individually, and an interpreter for AgentSpeak(L), an agent-oriented programming language that implements the BDI architecture. I have developed an interface that allows the BDI-based agent reasoning system to be used for guiding the behaviour of a character in an animation system. The use of AgentSpeak(L) is a promising approach for the high-level specification of complex computer animations. The conceptual model and its implementation are presented in distinct chapters. This separation aims at simplifying the comprehension of the proposed model, allowing its analysis first at a higher abstraction level, and after that to check programming details. This work also presents two 3-D animations used to illustrate the proposed approach. The main animation presented involves an agent that is situated in a dynamic environment; the agent continuously perceives the environment and reasons on how to act upon it based on its BDI mental state. The other application is quite simple, but useful to show some issues that are relevant for obtaining better performance from AgentSpeak(L) programs.
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Gelaim, Thiago Angelo. "Modelo de agentes e-BDI integrando confiança baseado em sistemas multi-contexto." reponame:Repositório Institucional da UFSC, 2016. https://repositorio.ufsc.br/xmlui/handle/123456789/167782.
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Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro Tecnológico, Programa de Pós-Graduação em Ciência da Computação, Florianópolis, 2016.Made available in DSpace on 2016-09-20T04:19:59Z (GMT). No. of bitstreams: 1 339453.pdf: 2208666 bytes, checksum: ae7c28d4d2b6fa440042d4447582854e (MD5) Previous issue date: 2016
Em sistemas multiagente, seus integrantes precisam interagir a fim de realizar seus objetivos. Existem situações em que entidades mal-intencionadas fazem parte do ambiente. Desta forma, para decidir com quem interagir é preciso considerar o comportamento dos candidatos. Neste contexto, mecanismos de confiança são utilizados como forma de proteção contra entidades fraudulentas. Na literatura são encontrados diversos modelos de confiança, em muitos casos considerando mais o aspecto funcional do modelo do que a sua influência no ciclo de raciocínio do agente. De acordo com a perspectiva do agente, um modelo de confiança é como uma caixa-preta . O objetivo deste trabalho é propor um modelo de agente em que a confiança faça parte de seu raciocínio. O modelo proposto, inspirado em BDI, é definido a partir de um sistema multi-contexto e faz uso de um modelo computacional de emoções, visando vincular a subjetividade das experiências do agente com a definição de confiança.
Abstract : In multiagent systems, its members need to interact in order to fulfill its goals. There are situations where malicious entities are inhabiting the environment. Thus, to decide with whom to interact it is necessary to consider the behavior of the candidates. In this context, trust mechanisms are used as a protection against fraudulent entities. The literature presents various trust models, in many cases considering more functional aspect of the model than its influence on the agent s reasoning cycle. According to the agent s perspective, a trust model is like a black box . The goal of this work is to propose an agent model where trust is part of its reasoning. The proposed model, inspired by BDI, is defined as a multi-context system and makes use of a computational model of emotions aiming to link the subjectivity of the agent s experiences with the definition of trust.
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Gelaim, Thiago Angelo. "Modelo de agentes e-BDI integrando confiança baseado em sistemas multi-contexto." reponame:Repositório Institucional da UFSC, 2016. https://repositorio.ufsc.br/xmlui/handle/123456789/162829.
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Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro Tecnológico, Programa de Pós-Graduação em Ciência da Computação, Florianópolis, 2016.Made available in DSpace on 2016-05-24T17:54:52Z (GMT). No. of bitstreams: 1 339453.pdf: 2208666 bytes, checksum: ae7c28d4d2b6fa440042d4447582854e (MD5) Previous issue date: 2016
Em sistemas multiagente, seus integrantes precisam interagir a fim de realizar seus objetivos. Existem situações em que entidades mal-intencionadas fazem parte do ambiente. Desta forma, para decidir com quem interagir é preciso considerar o comportamento dos candidatos. Neste contexto, mecanismos de confiança são utilizados como forma de proteção contra entidades fraudulentas. Na literatura são encontrados diversos modelos de confiança, em muitos casos considerando mais o aspecto funcional do modelo do que a sua influência no ciclo de raciocÃnio do agente. De acordo com a perspectiva do agente, um modelo de confiança é como uma  caixa-preta . O objetivo deste trabalho é propor um modelo de agente em que a confiança faça parte de seu raciocÃnio. O modelo proposto, inspirado em BDI, é definido a partir de um sistema multi-contexto e faz uso de um modelo computacional de emoções, visando vincular a subjetividade das experiências do agente com a definição de confiança.
Abstract : In multiagent systems, its members need to interact in order to fulfill its goals. There are situations where malicious entities are inhabiting the environment. Thus, to decide with whom to interact it is necessary to consider the behavior of the candidates. In this context, trust mechanisms are used as a protection against fraudulent entities. The literature presents various trust models, in many cases considering more functional aspect of the model than its influence on the agent s reasoning cycle. According to the agent s perspective, a trust model is like a  black box . The goal of this work is to propose an agent model where trust is part of its reasoning. The proposed model, inspired by BDI, is defined as a multi-context system and makes use of a computational model of emotions aiming to link the subjectivity of the agent s experiences with the definition of trust.
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Jeannes, Fernanda Mendez. "Um Modelo de Agente Econômico Cognitivo em um Sistema Microeconômico com Base no Conceito de Agentes BDI." Universidade Catolica de Pelotas, 2009. http://tede.ucpel.edu.br:8080/jspui/handle/tede/112.
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Previous issue date: 2009-12-22Simulações sociais em sistemas de agentes têm sido um tema presente na comunidade de Inteligência Artificial. O presente trabalho aborda estudos de conceitos relativos a um sistema microeconômico para modelagem de agentes econômicos cognitivos, com comportamento de consumidor e de produtor, com base no conceito do modelo de agentes BDI. A fim de destacar a importância desta modelagem, trabalhos relacionados à área de pesquisa são examinados, enfatizando a originalidade deste modelo de agente econômico cognitivo. Também são apresentados conceitos básicos inerentes a esta modelagem, tais como: trocas sociais e econômicas, e as interações entre os agentes. O conteúdo de microeconomia apresentado aborda os conceitos básicos de mercado e dos modelos de consumidor e de produtor utilizados na modelagem. Do mesmo modo, é apresentado um estudo do modelo de agentes BDI para a modelagem de agentes reativos e cognitivos. Estudos sobre um modelo básico de comportamento do consumidor, o processo de tomada de decisão e formação de comportamento e sobre Teoria da Firma são apresentados para embasar o comportamento dos agentes. Por fim, o modelo de um agente econômico cognitivo, com comportamento de consumidor e de produtor, é apresentado, bem como os resultados da simulação de um mercado com quatro agentes econômicos cognitivos
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Silva, Diego Gonçalves. "AgentSpeak(PL): uma nova linguagem de programação para agentes BDI com um modelo integrado de Redes Bayesianas." Universidade do Vale do Rio dos Sinos, 2011. http://www.repositorio.jesuita.org.br/handle/UNISINOS/3434.
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Quando este trabalho foi iniciado não era possível desenvolver de forma prática e direta softwares com agentes inteligentes onde suas crenças poderiam ser probabilidades relacionadas com seu ambiente, visto que as definições formais das linguagens disponíveis não previam tal possibilidade. Quando essa necessidade precisava ser levada em conta e implementada, devia-se lançar mão de técnicas avançadas de programação onde deveria haver a integração de ambientes de desenvolvimentos e linguagens, a fim de tornar a implementação factível. Este trabalho teve como objetivo o desenvolvimento de uma nova linguagem de programação orientada a agentes denominada AgentSpeak(PL), baseada em AgentSpeak(L), com o intuito de agregar o conceito de crenças probabilísticas através do uso de Redes Bayesianas sendo implementada através de uma extensão da ferramenta de programação Jason.
When this work was started it was not possible to develop so practical and straightforward software with intelligent agents where their beliefs could likely be related to their environment, as the settings formal language available did not foresee such a possibility. When this necessity had to be taken into account and implemented, one should resort of advanced programming techniques where there should be integration of development environments and languages in order to make the implementation feasible. This study aimed to develop a new language agent oriented programming called AgentSpeak (PL), based on AgentSpeak (L) with the intention of creating the concept of probabilistic beliefs through the use of Bayesian networks being implemented through an extension Jason's programming tool.
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Rosa, Stefan de Oliveira. "HRCSystem: sistema multiagente BDI como auxílio na gestão de profissionais por competências." Universidade do Vale do Rio do Sinos, 2009. http://www.repositorio.jesuita.org.br/handle/UNISINOS/2280.
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Previous issue date: 3Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
Este trabalho apresenta o desenvolvimento do HRCSystem (Sistema de Consulta a Recursos Humanos), desde concepção até os experimentos de validação. Intrínseco ao desenvolvimento do sistema estão os conceitos de áreas como Gestão de Projetos, Gestão por Competências e Engenharia de Software Orientada a Agentes. O principal objetivo do HRCSystem é auxiliar gerentes de projetos na escolha de um profissional que seja mais adequado à realização de uma atividade, considerando características de qualificação e disponibilidade deste profissional. Para isso, o HRCSystem implementa um modelo cognitivo para representar conceitos de competência humana e processos de gestão de competência de natureza psicológica. Este modelo cognitivo de competências também é proposto na dissertação, sendo outro importante resultado deste trabalho. Metodologias como TROPOS, Prometheus e Métodos Derivados de ITS (Intelligent Tutoring System) dão suporte às fases de análise e projeto do sistema. A fase de implementação é executada com aux
This work presents the development of the HRCSystem (System to Query Human Resources) from conception up to the experiments for validation. Intrinsic to the development of the application are the concepts of research areas as Project Management, Competencies Management and Agent-Oriented Software Engineering. HRCSystem goal is to assist project managers in choosing a professional that is more appropriate for some activity, considering the competencies and availability of the professional. To do so, HRCSystem implements a cognitive model aimed to represent human competency concepts and competence management processes of psychological nature. This cognitive model of competencies is also proposed in this work, being another important result of it. Methodologies like TROPOS, Prometheus and Methods Derived from ITS ( Intelligent Tutoring System) support analysis and design phases of the system. The implementation phase is executed with the help of AgentSpeak(L) language and JASON tool. Finally, both model and s
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Šalbaba, Vojtěch. "Multiagentní simulační model pro letecké formace." Master's thesis, Vysoké učení technické v Brně. Fakulta informačních technologií, 2013. http://www.nusl.cz/ntk/nusl-236382.
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This thesis deals with designing a model for simulation and visualisation of air combat tactics. It introduces air combat environment and describes a process for its modeling. Thesis describes basics of air combat, its principles and importance of chosen tactics. Using Jason programming language, artificial agents are created and chosen tactics are implemented. The process of implementing tacitcs is described from analysis to final implementation. Finaly, various types of agents are tested in mock combat against each other.
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White, Alan Gordon. "CAMP-BDI : an approach for multiagent systems robustness through capability-aware agents maintaining plans." Thesis, University of Edinburgh, 2017. http://hdl.handle.net/1842/31465.
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Rational agent behaviour is frequently achieved through the use of plans, particularly within the widely used BDI (Belief-Desire-Intention) model for intelligent agents. As a consequence, preventing or handling failure of planned activity is a vital component in building robust multiagent systems; this is especially true in realistic environments, where unpredictable exogenous change during plan execution may threaten intended activities. Although reactive approaches can be employed to respond to activity failure through replanning or plan-repair, failure may have debilitative effects that act to stymie recovery and, potentially, hinder subsequent activity. A further factor is that BDI agents typically employ deterministic world and plan models, as probabilistic planning methods are typical intractable in realistically complex environments. However, deterministic operator preconditions may fail to represent world states which increase the risk of activity failure. The primary contribution of this thesis is the algorithmic design of the CAMP-BDI (Capability Aware, Maintaining Plans) approach; a modification of the BDI reasoning cycle which provides agents with beliefs and introspective reasoning to anticipate increased risk of failure and pro-actively modify intended plans in response. We define a capability meta-knowledge model, providing information to identify and address threats to activity success using precondition modelling and quantitative quality estimation. This also facilitates semantic-independent communication of capability information for general advertisement and of dependency information - we define use of the latter, within a structured messaging approach, to extend local agent algorithms towards decentralized, distributed robustness. Finally, we define a policy based approach for dynamic modification of maintenance behaviour, allowing response to observations made during runtime and with potential to improve re-usability of agents in alternate environments. An implementation of CAMP-BDI is compared against an equivalent reactive system through experimentation in multiple perturbation configurations, using a logistics domain. Our empirical evaluation indicates CAMP-BDI has significant benefit if activity failure carries a strong risk of debilitative consequence.
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Fagundes, Moser Silva. "Integrating BDI model and Bayesian networks." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2007. http://hdl.handle.net/10183/10422.
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Individualmente, as linhas de pesquisa da Inteligência Artificial têm proposto abordagens para a resolução de inúmeros problemas complexos do mundo real. O paradigma orientado a agentes provê os agentes autônomos, capazes de perceber os seus ambientes, reagir de acordo com diferentes circunstâncias e estabelecer interações sociais com outros agentes de software ou humanos. As redes Bayesianas fornecem uma maneira de representar graficamente as distribuições de probabilidades condicionais e permitem a realização de raciocínios probabilísticos baseados em evidências. As ontologias são especificações explícitas e formais de conceituações, que são usadas em uma variedade de áreas de pesquisa, incluindo os Sistemas Multiagentes. Contudo, existem aplicações cujos requisitos não podem ser atendidos por uma única tecnologia. Circunstâncias como estas exigem a integração de tecnologias desenvolvidas por distintas áreas da Ciência da Computação. Esta dissertação trata a integração do modelo de agentes BDI (Belief-Desire-Intention) e das redes Bayesianas. Além disso, é adotada uma abordagem baseada em ontologias para representar o conhecimento incerto dos agentes. O primeiro passo em direção a integração foi o desenvolvimento de uma ontologia para representar a estrutura das redes Bayesinas. Esta ontologia tem como principal objetivo permitir a interoperabilidade agentes compatíveis com a arquitetura proposta. No entanto, a ontologia também facilita o entendimento necessário para abstrair os estados mentais e processos cognitivos dos agentes através de elementos das redes Bayesianas. Uma vez construída a ontologia, a mesma foi integrada com a arquitetura BDI. Através da integração do modelo BDI com as redes Bayesianas foi obtida uma arquitetura cognitiva de agentes capaz de deliberar sob incerteza. O processo de integração foi composto de duas etapas: abstração dos estados mentais através de elementos das redes Bayesianas e especificação do processo deliberativo. Finalmente, foi desenvolvido um estudo de caso, que consistiu na aplicação da arquitetura proposta no Agente Social, um componente de um portal educacional multiagente (PortEdu).Individually, Artificial Intelligence research areas have proposed approaches to solve several complex real-world problems. The agent-based paradigm provided autonomous agents, capable of perceiving their environment, reacting in accordance with different situations, and establishing social interactions with other software agents and humans. Bayesian networks provided a way to represent graphically the conditional probability distributions and an evidence-based probabilistic reasoning. Ontologies are an effort to develop formal and explicit specifications of concepts, which have been used by a wide range of research areas, including Multiagent Systems. However, there are applications whose requirements can not be addressed by a single technology. Circumstances like these demand the integration of technologies developed by distinct areas of Computer Science. This work is particularly concerned with the integration of Belief-Desire-Intention (BDI) agent architecture and Bayesian networks. Moreover, it is adopted an ontology-based approach to represent the agent’s uncertain knowledge. To bring together those technologies, it was developed an ontology to represent the structure of Bayesian networks knowledge representation. This ontology supports the interoperability among agents that comply with the proposed architecture, and it also facilitates the understanding necessary to abstract the agents’ mental states and cognitive processes through elements of Bayesian networks. Once specified the ontology, it was integrated with the BDI agent architecture. By integrating BDI architecture and Bayesian networks, it was obtained a cognitive agent architecture capable of reasoning under uncertainty. It was performed in two stages: abstraction of mental states through Bayesian networks and specification of the deliberative process. Finally, it was developed a case study, which consists in applying the probabilistic BDI architecture in the Social Agent, a component of a multiagent educational portal (PortEdu).
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Cioffi, Francesca. "Applicazione del linguaggio ad agenti Jason per la programmazione di alto livello di robot." Bachelor's thesis, Alma Mater Studiorum - Università di Bologna, 2009. http://amslaurea.unibo.it/8448/.
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I sistemi software rivestono nel campo dell'informatica un ruolo di fondamentale importanza. Negli ultimi anni una caratteristica richiesta ai sistemi è la decentralizzazione del controllo, nell'ottica di un sistema visto come
connessioni di parti che possono interagire, e dove ciascuna parte possiede un certo grado di autonomia nella scelta delle attività che devono essere compiute.
In tale contesto si introduce il paradigma degli agenti, in quanto include sia aspetti relativi ai modelli computazionali, sia aspetti relativi ai linguaggi.
Nella tesi si esplora l'applicazione del linguaggio di programmazione Jason applicato alla programmazione dei controllori di robot. In particolare, si esplora ciò che riguarda il comportamento individuale dell'agente.
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Zheng, Ning. "Mediation modeling and analysis forhigh-throughput omics data." Thesis, Uppsala universitet, Statistiska institutionen, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-256318.
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There is a strong need for powerful unified statistical methods for discovering underlying genetic architecture of complex traits with the assistance of omics information. In this paper, two methods aiming to detect novel association between the human genome and complex traits using intermediate omics data are developed based on statistical mediation modeling. We demonstrate theoretically that given proper mediators, the proposed statistical mediation models have better power than genome-wide association studies (GWAS) to detect associations missed in standard GWAS that ignore the mediators. For each ofthe modeling methods in this paper, an empirical example is given, where the association between a SNP and BMI missed by standard GWAS can be discovered by mediation analysis.
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Truong, Chi Quang. "Integrating cognitive models of human decision-making in agent-based models : an application to land use planning under climate change in the Mekong river delta." Thesis, Paris 6, 2016. http://www.theses.fr/2016PA066580/document.
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L'objectif initial de cette thèse est d'apporter une solution à ce problème en proposant, premièrement, une approche cognitive basée sur le paradigme appelé Belief-Desire-Intention (BDI) pour représenter les processus de prise de décision des acteurs humains, et deuxièmement, une validation de cette approche dans le contexte d'un modèle complet de changement d'usage des sols dans lequel la plupart des facteurs cités ci-dessus sont également simulés. Le résultat de ce travail est une approche générique qui a été validée sur un modèle intégrant le changement d'usage des sols d'une région située dans le Delta du Mékong au Vietnam. Nos contributions principales sont les suivantes : Intégration d’une architecture BDI au sein d'une plateforme de modélisation à base d'agents (GAMA) ;Conception d’un cadre générique baptisé « Multi-Agent Based Land-Use Change » (MAB-LUC) permettant de modéliser et de simuler les changements d’usage des sols en prenant en compte les décisions des agriculteurs ;Proposition d’une solution permettant d’intégrer et d’évaluer les facteurs socio-économiques et environnementaux dans le cadre de la planification agraire et d’intégrer MAB-LUC dans le processus existant proposé par la FAO.Ce travail, au-delà du cas d’étude concernant le Delta du Mékong, a enfin été conçu de façon générique afin que la méthodologie utilisée puisse être généralisée à la modélisation de systèmes socio-écologiques où les facteurs humains doivent être représentés avec précisionThe initial goal of this thesis has been then to address this problem by proposing, on one hand, a cognitive approach based on the Belief-Desire-Intention (BDI) paradigm to represent the decision-making processes of human actors in agent-based models and, on the second hand, a validation of this approach in a complete land-use change model in which most of the factors cited above have also been simulated.The outcome of this work is a generic approach, which has been validated in a complex integrated land-use change model of a small region of the Vietnamese Mekong Delta. Our main contributions have been:The integration of the BDI architecture within an agent-based modeling platform (GAMA); The design of the Multi-Agent Based Land-Use Change (MAB-LUC) framework that can take into account the farmers’ decision-making in the land-use change processes;The proposal of a solution to assess the socio-economic and environmental factors in land-use planning and to integrate the MAB-LUC framework into the land-use planning process of. I conclude by showing that this work, designed in a generic fashion, can be reused and generalized for the modeling of complex socio-ecological systems where individual human factors need to be represented accurately
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Faccin, João Guilherme. "Preference and context-based BDI plan selection using machine learning : from models to code generation." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2016. http://hdl.handle.net/10183/138209.
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A tecnologia de agentes surge como uma solução que fornece flexibilidade e robustez para lidar com domínios dinâmicos e complexos. Tal flexibilidade pode ser alcançada através da adoção de abordagens já existentes baseadas em agentes, como a arquitetura BDI, que provê agentes com características mentais de crenças, desejos e intenções. Essa arquitetura é altamente personalizável, deixando lacunas a serem preenchidas de acordo com aplicações específicas. Uma dessas lacunas é o algoritmo de seleção de planos, responsável por selecionar um plano para ser executado pelo agente buscando atingir um objetivo, e tendo grande influência no desempenho geral do agente. Grande parte das abordagens existentes requerem considerável esforço para personalização e ajuste a fim de serem utilizadas em aplicações específicas. Nessa dissertação, propomos uma abordagem para seleção de planos apta a aprender quais planos possivelmente terão os melhores resultados, baseando-se no contexto atual e nas preferências do agente. Nossa abordagem é composta por um meta-modelo, que deve ser instanciado a fim de especificar metadados de planos, e uma técnica que usa tais metadados para aprender e predizer resultados da execução destes planos. Avaliamos nossa abordagem experimentalmente e os resultados indicam que ela é efetiva. Adicionalmente, fornecemos uma ferramenta para apoiar o processo de desenvolvimento de agentes de software baseados em nosso trabalho. Essa ferramenta permite que desenvolvedores modelem e gerem código-fonte para agentes BDI com capacidades de aprendizado. Um estudo com usuários foi realizado para avaliar os benefícios de um método de desenvolvimento baseado em agentes BDI auxiliado por ferramenta. Evidências sugerem que nossa ferramenta pode auxiliar desenvolvedores que não sejam especialistas ou que não estejam familiarizados com a tecnologia de agentes.Agent technology arises as a solution that provides flexibility and robustness to deal with dynamic and complex domains. Such flexibility can be achieved by the adoption of existing agent-based approaches, such as the BDI architecture, which provides agents with the mental attitudes of beliefs, desires and intentions. This architecture is highly customisable, leaving gaps to be fulfilled in particular applications. One of these gaps is the plan selection algorithm that is responsible for selecting a plan to be executed by an agent to achieve a goal, having an important influence on the overall agent performance. Most existing approaches require considerable effort for customisation and adjustment to be used in particular applications. In this dissertation, we propose a plan selection approach that is able to learn plans that provide possibly best outcomes, based on current context and agent’s preferences. Our approach is composed of a meta-model, which must be instantiated to specify plan metadata, and a technique that uses such metadata to learn and predict plan outcomes. We evaluated our approach experimentally, and results indicate it is effective. Additionally, we provide a tool to support the development process of software agents based on our work. This tool allows developers to model and generate source code for BDI agents with learning capabilities. A user study was performed to assess the improvements of a tool-supported BDI-agent-based development method, and evidences suggest that our tool can help developers that are not experts or are unfamiliar with the agent technology.
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Emmerich, Franck. "Anticipating a bid/no-bid decision model for an ICT service company." Thesis, Högskolan i Gävle, Avdelningen för Industriell utveckling, IT och Samhällsbyggnad, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:hig:diva-25896.
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This report analyses and describes how the bid/no-bid decisions are made at one ICT service company. The analysis is based on current available research within the area of multi criteria decision analysis to enhance the company’s decision process. It proposes how the bid engagement decision can be structured and evaluated. Through a questionnaire at the ICT company, data from its own bids was collected to identify the factors perceived to be relevant to the bid/no bid decision. It is found that the factors can vary depending on industry, market and potentially bid situation, requiring experts’ assessment of which factors to use for each bid situation. Concluding the study, an initial bid model is proposed, but with reservations due to lack of validation in real life situations. A recommendation to expand the existing bid model with probability distribution based risk estimates is made.
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Zimmer, Janek. "Initialisierung des LM mit künstlichen Eingangsdaten zur Abschätzung orografischer Effekte auf die Niederschlagsverteilung bei idealisierten Strömungssimulationen." Universitätsbibliothek Leipzig, 2017. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-222260.
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Das Lokalmodell (LM) wurde für eine Reihe von Sensitivitätsuntersuchungen bezüglich orografischer Beeinflussung von Niederschlag verwendet. Für die Initialisierung des Modells mit Anfangs- und Randdaten wurde ein Schema entwickelt, welches eine horizontal homogene und stationäre Strömung aus einem einzelnen Vertikalprofil der benötigten atmosphärischen Variablen erstellt. Dabei wird hier auch der horizontale Luftdruckgradient berücksichtigt, wodurch eventuelle Auswirkungen der Coriolisterme auch ohne eine sehr große Entfernung des Zielgebietes vom Modellrand untersucht werden können. Simulationen mit idealisierten Eingangsfeldern können zur Verdeutlichung des Einflusses eines orografischen Hindernisses auf das dreidimensionale Strömungsfeld dienen. Außerdem sind sie zur Validierung bestimmter Parametrisierungen geeignet, da sich im Gegensatz zu realen Randdaten keine überlagerten synoptisch-skaligen Störungen im Modellgebiet befinden. Die hier verwendete Konvektionsparametrisierung nach Tiedtke (1989) zeigt unterschiedlich ausgeprägte Niederschlagsverteilungen und Flächenmittel in Abhängigkeit von der unterliegenden OrografieThe Lokalmodell (LM) has been used for a series of sensitivity studies treating orographic modification of precipitation. An initialization technique has been developed which generates a horizontally homogeneous and stationary flow out of a single vertical profile of the required atmospheric variables. Herein, the horizontal pressure gradient is considered as well, allowing to investigate the influence of the Coriolis terms without the need for the area under investigation to be far away from the model boundaries. Simulations with idealized initialization fields can help to illustrate the influence of orographic obstacles on the three-dimensional flow field. Furthermore, they enable to validate certain parameterizations because of the missing synoptic-scale disturbances, which are present using real boundary data. The chosen parameterization of convection after Tiedtke (1989) shows different distributions of precipitation and its area-averaged values depending on the underlying orography
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Bischof, Dorothea. "Modellorientierte Therapie bei Störungen des Leseerwerbs." Doctoral thesis, Humboldt-Universität zu Berlin, 2020. http://dx.doi.org/10.18452/21345.
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Ein ausreichendes Lesetempo, eine hohe Lesegenauigkeit und ein entwickeltes Leseverständnis sind in fast allen Schulfächern Voraussetzung für eine erfolgreiche Teilnahme am Unterricht. Internationale Schulleistungsstudien belegen, dass ein hoher Anteil von Schülern bereits in der Grundschule unzureichende Lesekompetenzen aufweist und daher auf zusätzliche Förder- oder Therapiemaßnahmen angewiesen ist. Im Hinblick darauf wurden in einem Gruppen-Prä-Post-Follow-Up-Design mit zweifacher Prä-Messung zwei unterschiedliche Interventionen zur Verbesserung der Lesefähigkeiten bei Zweit- und Drittklässlern evaluiert: Ein modellgeleitetes Therapieverfahren zur Verbesserung der Lesegeschwindigkeit von Wörtern und ein von Eltern durchgeführtes Fördertraining zur Verbesserung der Lesegenauigkeit und Lesegeschwindigkeit von Pseudowörtern. Zur Teilnahme an den Interventionen wurden 58 Zweit- und Drittklässler mit einem gravierenden Leserückstand ausgewählt und entweder dem Therapieprogramm oder dem Fördertraining zugeteilt. Beide Gruppen erhielten über 5 Wochen ein tägliches 45-minütiges Training. Während das Training der Therapiegruppe von einem ausgebildeten Therapeuten durchgeführt wurde und in der Schule stattfand, wurde das Training der Fördergruppe von Eltern zu Hause durchgeführt. Es wurden Veränderungen in der Lesegeschwindigkeit, dem Leseverständnis und verschiedenen Blickbewegungsparametern ausgewertet.In order to follow the lessons in school, children must be able to read with speed as well as with accuracy and a proven ability to comprehend texts. International school performance studies show that a high proportion of students already have inadequate reading skills in elementary school and therefore need additional support or therapy measures. Based on this observation, an evaluation of two different interventions among second- and third-graders is reported: A pre-post follow-up design with double pre-measurement, aiming at the increase of the students' reading skills. A model-guided therapy method for improving the reading speed of words and a parental training course for the improvement of reading accuracy and reading speed of pseudowords. 58 second- and third-graders with a serious reading backlog were selected to participate in the interventions and were assigned to either the therapy program or the parental training. Both groups received daily 45-minute training over a 5 week period. While the training of the therapy group was held by a therapist and took place at school, the training of the support group was carried out by parents at home. Changes in reading speed, reading comprehension and various eye movement parameters were evaluated.
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Rianço, Nelson Manuel Sobral. "Modelo com regimes para os preços e a liquidez de acções em bolsa." Master's thesis, Faculdade de Ciências e Tecnologia, 2009. http://hdl.handle.net/10362/4096.
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Dissertação apresentada à Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa para obtenção do grau de mestre em Matemática e Aplicações - Ramo Actuariado, Estatística e Investigação OperacionalLiquidez, nos mercados de acções, pode ser definida por várias quantidades concorrentes directamente observadas. Através da revisão da literatura concluímos que, apesar de um grande número de opiniões e dimensões da liquidez, os mais discutidos são o bid-ask spread (seguidamente designado por BAS) ver [12], [15],[26], [40], [46], [96], [108], [124] e [127] e o volume das transacções em [35], [104],[113], [132] e as suas referências. Uma série de estudos empíricos referenciados nos estudos citados, mostram a influência recíproca da liquidez nos níveis dos preços e dos níveis dos preços nas diversas medidas de liquidez. Iremos reportar neste trabalho, a análise estatística de ambos, o BAS e o volume das transacções, para um grande conjunto de acções estudadas, mostrando que a quantidade que tem melhores propriedades estatísticas que permitem o modelo log-normal é o volume das transacções expressa na moeda local. Propomos um modelo para a evolução do preço das acções em bolsa que incorpora a informação contida nos valores da liquidez expressa na moeda local. O modelo é dado por um sistema de equações diferenciais estocásticas, uma para o preço e outra para a liquidez, têm parâmetros de mudança de regime que mudam de acordo com as transformações dos limiares pelas trajectórias do processo. Por meio de um estudo de simulação, apresentamos algumas das propriedades do modelo e mostramos que permite recuperar algumas das características da evolução de uma acção típica do mercado de acções português.
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Moreira, Clarisse. "Bid/No-bid decisions in the international construction industry : A comparison between theoretical and practical perspectives." Thesis, Umeå University, Umeå School of Business, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-5721.
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Bid/no-bid decisions in international construction markets are considered difficult, being characterized by its uncertainties and complexities, especially in today’s highly competitive market. Additionally, it is claimed by some authors that many companies still utilize tools and methods that are fragmented, incomplete and rudimentary based on “personal intuition” or “previous-experience-based” (Han and Diekmann 2001a; Han and Diekmann 2001b). On the other hand, other authors emphasize that most of the bid/no-bid models found in the literature ‘remained in academic circles and did not find their way into the practical world’ (Wanous et al, 2000, pp.457). Thus, the focus of this work is to make a contribution towards the reduction of the actual gap between theoretical and practical bidding decision models and contribute to the development of a consistent model that could satisfactorily support the bid/no-bid decision for international construction projects. This way, an investigation of the practical bid/no-bid decision models is performed combined with an evaluation of the degree of applicability of theoretical models in practice. The research is based on a multiple case study analysis. The results suggest that although bidding decisions are still based on subjective judgments, the process applied by companies is formal and highly structured. It is a defined routine with a clear sequence of steps to be followed in which relevant information is analyzed by experienced staff. Additionally, it is designed to be followed by all bids in the companies, including formal presentations for the top management of the companies, who are actively involved in the decision. However, the results also reinforce that although some features of theoretical models can be observed in practice, none of them is being fully employed. Thus, it is possible to affirm that, although the current theoretical models bring some important highlights to bidding situations, they are still not fully suitable for the international construction environment. An important contribution can be done not only to the academic field but also to managerial one if future research focuses on the improvement of the practical models.
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Farrenkopf, Thomas. "Applying semantic technologies to multi-agent models in the context of business simulations." Thesis, Edinburgh Napier University, 2017. http://researchrepository.napier.ac.uk/Output/1033149.
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Agent-based simulations are an effective simulation technique that can flexibly be applied to real-world business problems. By integrating such simulations into business games, they become a widely accepted educational instrument in the context of business training. Not only can they be used to train standard behaviour in training scenarios but they can also be used for open experimentation to discover structure in complex contexts (e.g. complex adaptive systems) and to verify behaviours that have been predicted on the basis of theoretical considerations. Traditional modelling techniques are built on mathematical models consisting of differential or difference equations (e.g. the well-known system dynamics approach). However, individual behaviour is not visible in these equations. This problem is addressed by using software agents to simulate individuals and to model their actions in response to external stimuli. To be effective, business training tools have to provide sufficiently realistic models of real-world aspects. Ideally, system effects on a macroscopic level are caused by behaviour of system components on a more microscopic level. For instance, in modelling market mechanisms market participants can explicitly be modelled as agents with individual behaviour and personal goals. Agents can communicate and act on the basis of what they know and which communication acts they perform. The evolution of the market then depends on the actions of the participants directly and not on abstract mathematical expressions. Generally, agent-based modelling is a challenging task, when modelling knowledge and behaviour. With the rise of the so-called semantic web ontologies have become popular, allowing the representation of knowledge using standardised formal languages which can be made available to agents acting in a simulation. However, the combination of agent-based systems with ontologies has not yet been researched sufficiently, because both concepts (web ontology languages and agent oriented programming languages) have been developed independently and the link has not yet been built adequately. Using ontologies as a knowledge base allows access to powerful standardised inference engines that offer leverage for the decision process of the agent. Agents can then determine their actions in accordance with this knowledge. To model agents using ontologies creates a new perspective for multi-agent simulation scenarios as programming details are reduced and a separation of modelling aspects from coding details is promising as business simulation scenarios can be set up with a reduced development effort. This thesis focuses on how ontologies can be integrated utilising the agent framework Jadex. A basic architecture with layered ontologies and its integration into the belief-desire-intention (BDI) agent model is presented. The abstract level of the approach guarantees applicability to different simulation scenarios which can be modelled by creating appropriate ontologies. Examples are based upon the simulation of market mechanisms within the context of different industries. The approach is implemented in the integrated simulation environment AGADE which incorporates agent-based and semantic technologies. Simulations for different scenarios that model typical market scenarios are presented.
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Soto, Vaquero José Ricardo. "Evaluación de una prueba estadística para detectar endogeneidad en modelos Bid de uso de suelo." Tesis, Universidad de Chile, 2019. http://repositorio.uchile.cl/handle/2250/170778.
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Memoria para optar al título de Ingeniero CivilLos modelos de uso de suelo permiten analizar la interacción entre los sistemas de transporte y el mercado inmobiliario. Esto los vuelve una herramienta de gran importancia para la toma de decisiones que concluye en proyectos como una línea de metro, un edificio comercial o un nuevo plano regulador. Considerando el alcance y consecuencias que tienen esta clase de proyectos en la sociedad, resulta fundamental que los modelos propuestos sean consistentes y permitan realizar pronósticos que reflejen la realidad en escenarios futuros. Los modelos de uso de suelo actuales son desarrollados bajo un enfoque Bid de máxima postura aleatoria, que podrían sufrir de endogeneidad debido, entre otras cosas, a la omisión de atributos, difíciles de medir pero muy influyentes en lo observado. La detección y correc- ción de endogeneidad ha sido estudiada ampliamente en el contexto de elecciones discretas (Louviere et al., 2005; Guevara, 2015), pero no en el caso particular del modelo Bid. Se han desarrollado múltiples metodologías para estimar modelos Bid (Ellickson, 1981; Lerman y Kern, 1983) que varían en términos de eficiencia. En consideración de lo anterior, esta memoria propone el desarrollo de una prueba de hipótesis basada en la prueba de especificación de Hausman y McFadden (1984) que logre detectar endogeneidad en modelos Bid. La principal ventaja que presenta el test propuesto frente a otras opciones es el no requerir de supuestos adicionales ni del uso de variables instrumentales para ser aplicado. Para estudiar el test propuesto se desarrolla un experimento de Monte Carlo donde se evalúan los indicadores de size distortion y poder empírico del test, los que son contrastados con el método de funciones de control. Este último se propone como alternativa pese al inconveniente de exigir el uso de variables instrumentales. El experimento simula una ciudad monocéntrica compuesta por hogares de dos estratos socioeconómicos donde se realiza un remate de viviendas a partir de un conjunto de atributos dado, logrando un equilibrio de mercado controlando la distribución de hogares por estrato y suponiendo un precio pagado igual a la máxima postura observada. Luego, se procede a estimar el modelo omitiendo un atributo de la simulación, que deriva en una fuente de endogeneidad que permite evaluar el test. La simulación concluye que la prueba desarrollada es capaz de detectar endogeneidad bajo ciertas condiciones. No obstante, existen casos donde el test puede fallar. En particular, cuando la valoración del atributo omitido es diferente para cada estrato se observan caídas en el poder empírico del test. Por otra parte, la comparación realizada con funciones de control muestra que este último posee mayor poder, mas el uso de variables instrumentales sigue representando un inconveniente que el test propuesto logra subsanar.
Fondecyt No. 1150590
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Wilsdorf, Michael, Gabi Fischer, and Astrid Ziemann. "Einfluss der vertikalen Auflösung der Eingangsprofile bei einem Schallstrahlenmodell." Universität Leipzig, 2009. https://ul.qucosa.de/id/qucosa%3A16343.
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In der folgenden Ausarbeitung soll der Einfluss der vertikalen Auflösung der Eingangsprofile auf die Schallausbreitungsrechnungen eines Schallstrahlenmodells näher untersucht werden. Der Grund hierfür liegt in dem Auftreten eines „Schichtenproblems“ bei der Arbeit mit einem solchen Modell. Das bedeutet, dass je größer die vertikale Auflösung der Eingangsprofile ist, desto mehr weicht die mit dem Computermodell bestimmte Lösung von der analytischen ab. Im folgenden Beitrag werden verschiedene vertikale Auflösungen untersucht und es wird gezeigt, dass eine höhere Auflösung dieses Problem lösen kann. Die Berechnungen erfolgen mit dem Schallstrahlenmodell SMART. Dieses Modell basiert auf der Berechnung des Weges, den der Schall in einer geschichteten Atmosphäre zurücklegt. Die Berechnungsgrundlage für das Strahlenmodell bilden dabei aus Radiosondendaten interpolierte, sowie klimatologisch klassifizierte Temperatur- und Windprofile. Diese Untersuchungen stellen eine notwendige Grundlage bei der Analyse und Interpretation der durch ein Strahlenmodell gewonnenen Dämpfungsberechnungen dar.In the following article, effects of the vertical resolution of input data on numerical sound attenuation simulations are investigated. The reason for this lies in the occurrence of a „layer problem“ during work with such a model. That means, even larger the vertical resolution of the input profiles is, so much more the calculated answer deviates from the analytic. Therefore, different vertical resolutions are examined. The analyzed results show that a higher resolution can solve this problem. Calculations are carried out using the sound ray model SMART which considers the dependency of sound ray propagation on stratified atmosphere. As a basis for calculating the sound ray paths interpolated and climatologically classified profiles of temperature and wind obtained from radiosonde data are utilized. These investigations provide a basis for the analysis and interpretation of attenuation calculations derived from a sound ray model.
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Rose, Melanie. "Soul Line Dancing Among African American Women in the Church: an Expectancy-value Model Approach." Thesis, University of North Texas, 2012. https://digital.library.unt.edu/ark:/67531/metadc149658/.
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Guided by the expectancy value model of achievement choice, this study examined the relationships among expectancy value constructs (expectancy related beliefs and subjective task values), effort and intention for future participation in a culturally specific dance, soul line, among African American adult women in the church setting. Participants were 100 African American women who were members of the women’s ministries from four predominantly African American churches in the Dallas/Ft. Worth metropolitan area. Participants completed a 20-minute soul line session and responded to survey questions, validated in previous research, assessing their expectancy-related beliefs, subjective task values, effort, intention for future participation and physical activity. This was the first study to use the expectancy value model as a guide to determine motivations attached to physical activities among African American adult women. Usefulness, a component of subjective task values, emerged as a predictor of intention for future participation. Eighty-one percent of the women did not meet physical activity guidelines for aerobic activity. Of those inactive women 60% indicated an interest in doing soul line dancing often at their church after one short exposure to the activity as indicated by the strongest possible response to both intention questions. A slightly smaller percent of the active women provided with a strong positive response for future intention. These findings suggest that soul line dancing is a practical avenue to increase physical activity among African American women in the church. Future research should test this theoretical model on a wider variety of individuals who are sedentary to physically active, measure actual participation, and directly measure BMI and physical activity.
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Alotaibi, Saud Saad. "The international contractor's decision to invest : a strategic risk management decision model for public private partnership projects in Saudi Arabia." Thesis, Heriot-Watt University, 2016. http://hdl.handle.net/10399/3161.
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One of the main sources of risks that influence potential project success is the project selection decision, especially for international contractor organisations looking for an opportunity to invest in public private partnership projects in foreign countries. Project selection decision, which involves the bid/no bid decision, is a critical investment decision needs to be made based on concrete project evaluation and risks identifications; where negative-risk is in place if there is an absence of a rational basis at the time of making such a decision. Thus, negative consequences of such a decision might occur. The bid/no bid decision necessitates an effective project evaluation and risk identification from various aspects with consideration of several internal and external factors in order to achieve project success. Bidding for PPP projects overseas without efficiently applying risk management tools and techniques to evaluate both the project and the organisation’s current situation and capability might result either in large losses or consumption of time and resources that could have been avoided. The prime aim of this research is to develop a strategic investment decision model from the perspective of risk management, in order to facilitate the decisions of international contractors who intend to invest in public private partnership projects in the Saudi Arabian construction industry. This aim requires establishing a link between the risk management process and the organisation's strategy and its current situation, and identifying risks involved in the bid/no bid decision, PPP projects, and international investment in order to provide an effective computer-based model that is capable of organising the bid/no bid decision in a rational, logical, flexible, and user-friendly manner. The pragmatic triangulation philosophy approach is adopted as the best research methodology that allows two types of research strategy to be combined in order to accomplish the research aim and objectives. Thus, the methods used are qualitative interviews and a quantitative questionnaire-based survey. The findings of this research identified critical success factors of international contractors’ bidding decisions for PPP projects in the Saudi Arabian construction industry. In particular, seventy-seven factors affecting the bid/no bid decision were used as a foundation for development of a Strategic Risk Management Decision Model (SRMDM), available at www.srmdm.com.
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Tang, Yuxiao. "Valuation of Mortgage Backed Securities with Prepayment using BDT Model and Monte Carlo Methods." Digital WPI, 2015. https://digitalcommons.wpi.edu/etd-theses/1184.
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Mortgage backed securities are one of the most important asset classes available to fixed income investors. They are also essential to the functioning of the financial and housing market by providing liquidity to the home mortgage market. Proliferation and wide spread acceptance of mortgage backed securities resulted in a significant deduction of the interest rates for home mortgages. The 2007-2010 financial crisis sparked enhanced scrutiny of the accuracy of the pricing of mortgage backed securities. The purpose of the present thesis is to develop a computer based mathematical methodology to accurately price individual mortgages that are the fundamental assets underlying every mortgage backed security. The focus of this paper is to correctly account for inherent interest rate and prepayment risk. Default risk is not subject of this project. Interest rate risk is handled in the framework of the arbitrage free Black-Derman-Toy (BDT) model. Public Securities Association’s (PSA) model is used to simulate prepayment risk. Monte Carlo simulation methodology is developed to evaluate the properly discounted current value of the risky cash flows and hence value the mortgages. The computational algorithms are implemented in R.
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Chandrasekar, Kameshwar. "Search-space Aware Learning Techniques for Unbounded Model Checking and Path Delay Testing." Diss., Virginia Tech, 2006. http://hdl.handle.net/10919/27048.
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The increasing complexity of VLSI designs, in recent years, poses serious challenges while ensuring the correctness of large designs for functionality and timing. In this dissertation, we target two related problems in Design Verification and Testing: Unbounded Model Checking and Path Delay Fault Testing, that commonly suffer from extremely large memory requirements. We propose efficient representations and intelligent learning techniques that reason on the problem structure and take advantage of the repeated search space, thereby alleviating the memory required and time taken to solve these problems.
In this dissertation, we exploit Automatic Test Pattern Generation (ATPG) for Unbounded Model Checking (UMC). In order to perform unbounded model checking, we need the core image / preimage computation engines that perform forward / backward reachability analysis. First, we develop an ATPG engine, with search-space aware learning, that computes ``all solutions" for a given target objective and stores it as a decision diagram. We propose efficient decision selection heuristics and derive a suitable cut-set metric to quickly obtain a compact solution set. The solution set that is obtained, with the initial state set as the objective, represents the one-cycle preimage. In order to use the preimage state set as the objective in the subsequent iterations, we propose efficient techniques to convert a decision diagram into clauses/circuit. We propose a node-based conversion scheme that derives the functionality of each node in the decision diagram. The proposed scheme contains the size of the state set and helps to iteratively compute the preimage for many cycles until a fixed point / desired state is reached.
Further, we gear the ATPG engine to directly compute the circuit cofactors, rather than individual solutions. The circuit cofactors contain a large number of solutions and hence capture a larger solution space. We also propose efficient learning techniques to prune the cofactor space and accelerate preimage computation. Then, we develop an exclusive image computation procedure that branches on the combinational inputs of the circuit and projects the values on the next state flip-flops as the image. We perform learning on the input solution space and incrementally store the image obtained as a decision diagram. We consistently show, with our experimental results, that our techniques are better than the existing techniques in terms of both performance and capacity.
In the case of delay testing, we consider the test generation for path delay fault (PDF) model, which is the most accurate in characterizing the cumulative effect of distributed delays along each path in a circuit. The main bottle-neck in the ATPG for PDFs is the exponential number of paths in a circuit. In this work, we use the circuit information to analyze the common segments shared by different paths in a circuit. Based on the common sensitization constraints, we propose to identify the ``untestable core of segments" that cannot be sensitized together. We use these segments to identify the conflict search space for a huge number of untestable path delay faults apriori and prune them on-the-fly during test generation. Experimental results show that a huge number of untestable path delay faults are identified and it helps to accelerate test generation.Ph. D.
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Vimjam, Vishnu Chaithanya. "Strategies for SAT-Based Formal Verification." Diss., Virginia Tech, 2007. http://hdl.handle.net/10919/26078.
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Verification of digital hardware designs is becoming an increasingly complex task as the designs are incorporating more functionality, becoming complex and growing larger in size. Today, verification remains a bottleneck in meeting time-to-market requirements and consumes more than 70% of the overall design-costs. Traditionally, verification has been done using simulation-based approaches, where a set of appropriate test-stimuli is used by the designer. As the designs become more complex, however, simulation-based techniques often fail to capture corner-case errors. Furthermore, unless exhaustively tested, these approaches do not guarantee the correctness of a system with respect to its specifications. As a consequence, formal methods for design verification have been sought after. In formal verification, the conformance of a design to a given set of specifications is proven mathematically, thereby leaving no room for unexplored search spaces. Despite the exponential time/memory complexities often involved within the formal approaches, they have shown promise in capturing subtle bugs, which were missed otherwise.
In this dissertation, we focus on Boolean Satisfiability (SAT) based formal verification, which has gained tremendous importance in the recent past. Importantly, SAT-based approaches often alleviate the memory explosion problem, which had been a bottleneck of the traditional symbolic (Binary Decision Diagram based) approaches. In SAT-based techniques, the set of verification tasks are converted into a set of Boolean formulae, which are checked for satisfiability using a SAT solver. These problems are often NP-complete and are prone to an explosion in the required run-time. To overcome this, we propose novel strategies which utilize both structural and logical information of a sequential circuit. In particular, we devise techniques to extract non-trivial invariants of a design, strengthen properties such that they can be proven faster and interleave bounded reachability analysis with bounded model checking. We provide the necessary algorithms and implementation details in order to automate the proposed techniques. Experiments conducted on a variety of benchmark circuits show that orders of magnitude improvement in overall run-times can be achieved via our techniques compared to the existing state-of-the-art SAT-based approaches.Ph. D.
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Gruber, Alfred. "A taxonomy of risk-neutral distribution methods : theory and implementation /." [S.l. : s.n.], 2003. http://www.gbv.de/dms/zbw/362419094.pdf.
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Morgado, Joana Nazaré de Castro Soares. "A modelling approach to estimate the incidence of salmonellosis in humans in Portugal." Master's thesis, Universidade de Lisboa. Faculdade de Medicina Veterinária, 2015. http://hdl.handle.net/10400.5/8861.
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Dissertação de Mestrado Integrado em Medicina VeterináriaEstimates of foodborne illness are relevant for setting food safety priorities and making public health policies. Salmonella spp. is one of the most important pathogens causing foodborne disease. In 2010, despite its progressive decrease in the European Union (EU), the incidence of salmonellosis was still 21.5 cases per 100,000 inhabitants, with a total of 99,020 confirmed cases of human salmonellosis reported by the 31 countries of the EU Member States (MSs). The objectives of this study are to estimate the burden of illness of salmonellosis in Portugal, to account for the domestically acquired, foodborne illness, while identifying data gaps and areas for further research. Estimates of illness due to Salmonella were based on data from 2000-2010 of the Portuguese reported laboratory-based surveillance system, relevant international literature and the Portuguese census population for 2010. The model approach - Burden of Illness (BoI) - defined as the impact of a health problem in an area or population measured by the incidence or number of cases, required accounting for underreporting and underdiagnosis, and estimating the proportion of illness domestically acquired and through foodborne transmission. The uncertainty was accounted with Monte Carlo simulations with 100,000 iterations, generating a mean estimate and 90% credible interval, using the program @Risk 6 (Palisades Corporation). The estimated number of salmonellosis cases is approximately 93 (52,04 –111,23) times higher than the reported from surveillance (239 cases of salmonellosis in 2010). It was estimated that there were 22,201 (11,476 – 35,956) episodes of domestically acquired foodborne Salmonellosis in Portugal for 2010. The multipliers for underreporting and underdiagnosis in Portugal were of 1 and 111.23, respectively. This was the first study to estimate foodborne salmonellosis cases in Portugal.
RESUMO - A análise de dados referentes à incidência de doenças de origem alimentar é crucial para a melhoria da segurança alimentar e para a revisão das políticas de Saúde Pública num país. A Salmonella spp. é um dos agentes etiológicos de zoonoses transmitidas por alimentos de maior relevância em todo o mundo. Em 2010, apesar da redução progressiva da sua incidência na União Europeia (EU), ainda se atingem valores de 21,5 casos de salmonelose por 100.000 habitantes nos 31 Estados-Membro (EM) da UE. Este estudo teve por objectivos: calcular a “Carga de Doença” causada por Salmonella spp. em Portugal; estimar os casos de salmonelose domesticamente adquiridos e de origem alimentar; e identificar lacunas no sistema de vigilância existentes, propondo linhas de investigação futuras. Os dados obtidos para calcular a incidência de salmonelose em Portugal, num período de tempo entre 2000 e 2010, foram recolhidos no sistema de vigilância de índole laboratorial; em artigos científicos e no recenseamento da população Portuguesa em 2010. O modelo criado, descrito como o que estima a “Carga da Doença”, caracteriza o impacto de um problema de saúde numa área ou população, através da incidência ou do número de casos observados. Faz ajustamentos para possíveis casos que não são reportados pelo sistema de vigilância e para casos que, apesar de existirem, não foram diagnosticados. Termina por calcular a proporção de casos de salmonelose contraídos por via alimentar e adquiridos domesticamente, incorporando a incerteza que os resultados possam acarretar. A incerteza foi calculada pelo método Monte Carlo, no programa @Risk 6 (Palisade Corporation), com simulações de 100.000 iterações, criando uma média estimativa e intervalos de credibilidade de 90%. O modelo de “Carga de Doença” gerou ocorrências de casos de salmonelose, 93 (52,04 –111,23) vezes superiores aos reportados pelo sistema de vigilância vigente (239 casos de salmonelose em 2010). Em 2010, foram estimados 22,201 (11,476 – 35,956) episódios de salmonelose transmitida por via alimentar e adquirida domesticamente. Os “multiplicadores” obtidos para a “subnotificação” e o “subdiagnóstico” foram, respectivamente, de 1 e 111,23. Este trabalho, pioneiro no cálculo da incidência de casos de salmonelose em Portugal por exposição alimentar, pretende ser um contributo válido e rigoroso para o estudo científico de uma doença, de grande incidência e da maior importância, em saúde pública.
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Kathstede, Gerd. "Die Verfassungsmässigkeit der Gewerbesteuer und das Modell der kommunalen Einkommen- und Gewinnsteuer (BDI-VCI-Modell) /." Aachen : Shaker, 2008. http://d-nb.info/989282570/04.
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Zimmer, Janek. "Initialisierung des LM mit künstlichen Eingangsdaten zur Abschätzung orografischer Effekte auf die Niederschlagsverteilung bei idealisierten Strömungssimulationen." Wissenschaftliche Mitteilungen des Leipziger Instituts für Meteorologie ; 37 = Meteorologische Arbeiten aus Leipzig … und Jahresbericht … des Instituts für Meteorologie der Universität Leipzig ; 11 (2006), S. 149-152, 2006. https://ul.qucosa.de/id/qucosa%3A15515.
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Das Lokalmodell (LM) wurde für eine Reihe von Sensitivitätsuntersuchungen bezüglich orografischer Beeinflussung von Niederschlag verwendet. Für die Initialisierung des Modells mit Anfangs- und Randdaten wurde ein Schema entwickelt, welches eine horizontal
homogene und stationäre Strömung aus einem einzelnen Vertikalprofil der benötigten atmosphärischen Variablen erstellt. Dabei wird hier auch der horizontale Luftdruckgradient berücksichtigt, wodurch eventuelle Auswirkungen der Coriolisterme auch ohne eine sehr große Entfernung des Zielgebietes vom Modellrand untersucht werden können. Simulationen mit idealisierten Eingangsfeldern können zur Verdeutlichung des Einflusses eines orografischen Hindernisses auf das dreidimensionale Strömungsfeld dienen. Außerdem sind sie zur Validierung bestimmter Parametrisierungen geeignet, da sich im Gegensatz zu realen Randdaten keine überlagerten synoptisch-skaligen Störungen im Modellgebiet befinden. Die hier verwendete Konvektionsparametrisierung nach Tiedtke (1989) zeigt unterschiedlich ausgeprägte Niederschlagsverteilungen und Flächenmittel in Abhängigkeit von der unterliegenden Orografie.The Lokalmodell (LM) has been used for a series of sensitivity studies treating orographic modification of precipitation. An initialization technique has been developed which generates a horizontally homogeneous and stationary flow out of a single vertical profile of the required atmospheric variables. Herein, the horizontal pressure gradient is considered as well, allowing to investigate the influence of the Coriolis terms without the need for the area under investigation to be far away from the model boundaries. Simulations with idealized initialization fields can help to illustrate the influence of orographic obstacles on the three-dimensional flow field. Furthermore, they enable to validate certain parameterizations because of the missing synoptic-scale disturbances, which are present using real boundary data. The chosen parameterization of convection after Tiedtke (1989) shows different distributions of precipitation and its area-averaged values depending on the underlying orography.
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Jurcevic, Sanja. "MicroRNA expression profiling in endometrial adenocarcinoma." Doctoral thesis, Örebro universitet, Institutionen för hälsovetenskap och medicin, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:oru:diva-41640.
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Musaad, Salma MA. "Anthropometric Measures of Obesity and the Association with Asthma and Other Allergic Disorders: Cincinnati Children’s Allergy and Immunology Clinic Cohort." University of Cincinnati / OhioLINK, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1192570691.
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Castro, Millades de Carvalho. "Risco na variação de preços agropecuários: um estudo para os mercados de soja, milho e boi gordo no município de Rio Verde-GO, 2004 a 2014." Universidade Federal de Goiás, 2016. http://repositorio.bc.ufg.br/tede/handle/tede/6057.
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Fundação de Amparo à Pesquisa do Estado de Goiás - FAPEG
Volatility in the prices of commodities and the financial return of agricultural activities affect the choice of what to produce. The present work investigates volatilities in prices of cattle, soybeans, and corn in Rio Verde (GO, Brazil), the choice of this region should be the importance of the city in the state and national agricultural production. For this study, we analyze weekly prices of corn, soybeans and cattle in Rio Verde spot market from 2004 to 2014, using Time Series Analysis and Value at Risk. The examination of the series pointed to the presence of a conditional variance. Therefore the ARCH / GARCH models were applied. The model selected to soybean was the IGARCH (2.1) and to corn and cattle the EGARCH (1.1). Due to disproportion between the traded prices and volumes it was not possible to perform the VAR series comparison. Therefore we used the ratio between the VAR and revenue of each product to compare between markets. Results showed a higher ratio for the cattle series indicating that volatility affects cattle producers’ income more than that of soybean or corn producers in Rio Verde (GO), which resulted in the reduction of this activity in the region.
A volatilidade nos preços das commodities e o retorno financeiro das atividades agropecuárias afetam a escolha do que produzir. O presente trabalho visa investigar as volatilidades nos preços do boi e das culturas de soja e milho para o município de Rio Verde (GO, Brasil), no período de 2004 a 2014, a escolha dessa região deve-se a importância do município na produção agropecuária estadual e nacional. Para tanto, utilizou-se de dados semanais de preços de milho, soja e boi no mercado físico de Rio Verde no período de 2004 a 2014. A metodologia usada foi a usual de análise de séries temporais e cálculo do Value at Risk (VaR). O exame das séries apontou a presença de variância condicional, sendo então aplicados os modelos ARCH/GARCH.O modelo selecionado para soja foi o IGARCH (2,1) e para milho e boi o EGARCH (1,1). Posteriormente, o cômputo do VaR para cada uma das séries não é suficiente para comparação, devido a desproporção entre os preços e os volumes negociados. Logo, para que fosse possível a comparação entre os mercados, utilizou-se da razão entre VaR e a receita de cada produto. Os resultados apontaram que em média, a razão foi maior para a série bovina. Portanto, a volatilidade compromete a receita dos produtores bovinos mais do que os agricultores de milho e soja no município de Rio Verde (GO), o que implicou na redução dessa atividade na região.
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Weber, Christoph. "Uncertainty in the electric power industry : methods and models for decision support /." New York : Springer, 2005. http://aleph.unisg.ch/hsgscan/hm00145851.pdf.
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Hess, Euodia. "Boron-doped Diamond Sensors for the Determination of Organic Compounds in Aqueous Media." Thesis, University of the Western Cape, 2010. http://etd.uwc.ac.za/index.php?module=etd&action=viewtitle&id=gen8Srv25Nme4_5310_1305022937.
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In electrochemical oxidation treatment of wastewater, the electrode material is an important parameter in optimizing oxidative electrochemical processes, since the mechanism and products of several anodic reactions are known to depend on the anode material. The electrochemical oxidation of benzaldehyde, nitrobenzene and m-cresol on bare boron-doped diamond (BDD) electrode was investigated. Cytochrome c was then electrochemically immobilsed onto the functionalized BDD electrode by cyclic voltammetry. Oxidation and reduction reaction mechanism of each flavonoid was studied. There was one oxidation and reduction peaks for quercitin and catechin respectively, and two oxidation and two reduction peaks for rutin. The cytochrome c modified BDD electrode showed good sensitivity for all three flavonoids and low detection limits i.e. 0.42 to 11.24 M as evaluated at oxidation and reduction peaks, respectively.
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Loonat, Naadhira. "Investigating depression and quality of life in adults diagnosed with HIV or AIDS." Thesis, University of the Western Cape, 2009. http://etd.uwc.ac.za/index.php?module=etd&action=viewtitle&id=gen8Srv25Nme4_5878_1363780893.
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HIV and AIDS are disease conditions that have led to high mortality rates in Southern Africa since the late 1970s. The socio-economic system has led to the unequal spread of resources&rsquo
and vulnerability and exposure to HIV is more prevalent in poorer communities. The added burden of life stresses cause for many to be isolated and stigmatised and are often not equipped with the necessary support and coping skills to deal with the magnitude of these circumstances. There is a high prevalence of mental disorders and especially depression amongst individuals infected with either HIV or AIDS. Research shows that stressful life events can impact HIV course progression and impacts the QoL of those infected with HIV or AIDS. Given the social and psychological context of HIV and AIDS, the aim of the study was to examine the relationship between depression and QoL in a sample of adults diagnosed with HIV or AIDS. This quantitative, cross-sectional study used the Becks Depression Inventory II (BDI II) and the Quality of Life Enjoyment and Satisfaction Questionnaire (Q-LES-Q), to measure the variables concerned. This battery of
questionnaires was administered to a purposive sample of adult individuals diagnosed with HIV or AIDS residing in a previously disadvantaged area in the Cape Metropole region. Using SPSS,
data was analysed and descriptive and inferential statistics were conducted. The study found that there were more women than men with HIV or AIDS that were found to be depressed (mild, moderate and severe depression). Furthermore, the depressive state increased when the progression of the disease increased. There were generally no significant differences in the QoL
experienced within various areas of life and overall life satisfaction experienced. However, the QoL experienced in work was lower. There was a significant relationship between the depressed state and QoL and life satisfaction experienced in household duties and tasks. The contribution of this study includes informing the larger research project, with regards to future treatment
regimes. It will update statistics on the prevalence of depression and QoL of adults diagnosed with HIV or AIDS in the area. This study is framed within a biopsychosocial model and is
theoretically underpinned by Beck&rsquo
s theory of depression. Key words: HIV, AIDS, adults, depression, quality of life (QoL), Beck Depression Inventory II (BDI II), Quality of Life Enjoyment and Satisfaction Questionnaire (Q-LES-Q), Antiretrovirals (ARV&rsquo
s), prevalence data, correlations.
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Kathstede, Gerd [Verfasser]. "Die Verfassungsmäßigkeit der Gewerbesteuer und das Modell der kommunalen Einkommen- und Gewinnsteuer (BDI/VCI-Modell) / Gerd Kathstede." Aachen : Shaker, 2008. http://d-nb.info/1162792221/34.
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Vandi, Silvia. "Progettazione e Sviluppo di un BDI Personal Assistant Agent per la generazione di Warning in ambito medico: il sistema Trauma Tracker come caso di studio." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2018. http://amslaurea.unibo.it/15585/.
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Trauma Tracker è un progetto che nasce da una collaborazione tra l'università di Bologna ed il Trauma Center dell'ospedale Bufalini di Cesena, con l'obiettivo di creare un assistente digitale in grado di assistere i medici tracciando il trauma e creando automaticamente report. La tesi si pone come obiettivo lo studio e lo sviluppo prototipale di un agente cognitivo basato su modello BDI per la generazione automatica di Warning durante la gestione di un trauma, estendendo le funzionalità del sistema esistente.
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Lendacký, Peter. "Modely úrokovej miery a ocenenie úrokových opcií." Master's thesis, Vysoká škola ekonomická v Praze, 2010. http://www.nusl.cz/ntk/nusl-18693.
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The interest rate dynamics is an important fundamental for valuation more complex structures of interest rate derivatives. The goal of this diploma thesis is to describe the use of models of interest rate for interest rate option pricing. The paper could be logically divided into two parts, the theoretical one and practical one. In the first part the essentials for pricing theory are introduced as risk neutrality, martingales, stochastic differential calculus, and theory of arbitrage. On their basis four basic yield curve models are derived, Vasicek model, model Cox-Ingersoll-Ross , Black-Derman-Toy and two factor Heath-Jarrow-Morton model. Second part provides the analysis of yields of U.S. Treasury bonds with different maturity. At the end CIR model and BDT binomial tree are used for valuation of option on 10 years yield.
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Palijanskas, Marius. "Inovacijų diegimas Lietuvos įmonėse: proceso plėtra bei ekonominis vertinimas." Master's thesis, Lithuanian Academic Libraries Network (LABT), 2008. http://vddb.library.lt/obj/LT-eLABa-0001:E.02~2008~D_20080929_113541-06707.
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Magistro baigiamajame darbe nagrinėjama Lietuvos įmonių inovacinė veikla, inovacijų išlaidų dinamika, palyginami inovatyvių įmonių produktyvumo ir darbo našumo duomenys, bei aptariamos inovacijų finansavimo šaltinių tendencijos. Siekiant įvertinti inovacijų diegimo Lietuvose įmonėse proceso plėtrą bei ekonominį jo aspektą, pateikiama statistinių skaičiavimų bei teorinių prielaidų, nusakančių netiesioginį inovacijų poveikį šalies ekonomikos konkurencingumui, bendram šalies inovatyvumo potencialui. Siekiama pateikti situacijos analizę ne tik Lietuvoje, bet ir palyginti Lietuvą Europos Sąjungos šalių kontekste. Tam tikrų rodiklių (apyvartos, darbo našumo, finansavimo šaltinių ir pan.) išskyrimas įgalina plačiau įžvelgti priežastis bei veiksnius įtakojančius šalies įmonių inovatyvumo laipsnį. Magistro baigiamasis darbas susideda iš trijų dalių. Teorinėje darbo dalyje yra nagrinėjami inovacijų sąvokų ir inovacinės veiklos teoriniai aspektai, galimos inovacijų rizikos, konkurencingumo didinimo prielaidos, palankių inovatyviam verslui sąlygų sukūrimas. Tiriamojoje darbo dalyje yra atliktas Lietuvos įmonių inovacinės veiklos bei plėtros galimybių vertinimas, nustatyta inovacijų įtaka atskiriems rodikliams, jų dydis bei svarba, taip pat santykinai palyginami Lietuvos atskiri inovatyvumo indeksai su ES šalimis. Trečiojoje darbo dalyje pateikiamas Lietuvos inovacinės veiklos modelis ES šalių pavyzdžiu, kuriame nurodomas naujas modifikuotas Inovatyvumo indeksas.The aim of the master thesis is analysis of Lithuanian companies innovative activities, dynamics of innovation costs, comparing innovative companies‘ and labour productivity, also discussing about finance support tendencies of innovations. To rate process development and establishment of innovations in Lithuanian companies, likewise economical it aspect, it is shown by using statistical methods and theoretical tendencies analysis, which proves indirect innovations impact into country‘s competitiveness, also overal innovations potential in the country. Furthermore, it is done with a showing situation context not only in Lithuania, but also compares it with Europe Union countries. Certain indicators exclusion (like turnover, labour productivity, sources of finance support) helps to enlarge a view of the reasons, likewise enabling factors for innovation degree of country companies. Master Final Work consists of three parts. In theoretic part there is researching of innovation concept and innovative activity theoretical aspects, possible risks for innovations, suggestions for competitiveness improving. In practise part of the work, there are established estimation of innovative Lithuanian companies’ activities and development opportunities, determined innovation influence over certain indicators, their sizes and interests, either comparison of distinct innovative indexes of Lithuania and Europe Union countries. On the third part of the work there is composed Lithuanian... [to full text]
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Künkler, Boris. "Mechanismenorientierte Lebensdauervorhersage unter Berücksichtigung der Mikrostruktur : Modellentwicklung, Verifikation und Anwendung /." Düsseldorf : VDI-Verl, 2007. http://bvbr.bib-bvb.de:8991/F?func=service&doc_library=BVB01&doc_number=016244991&line_number=0001&func_code=DB_RECORDS&service_type=MEDIA.
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Liu, Jinxiang. "Investigation of low cycle fatigue in shot peened components." Düsseldorf VDI-Verl, 2009. http://d-nb.info/996623914/04.
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Lanzetta, Vitor Bianchi. "Uma comparação entre modelos de previsão de preços do boi gordo paulista." Universidade de São Paulo, 2018. http://www.teses.usp.br/teses/disponiveis/11/11132/tde-17072018-145429/.
Full textAbstract:
O estudo comparou o desempenho preditivo dos modelos de previsão de redes neurais e de suavização exponencial, empregando dados diários do preço da arroba do boi gordo futuro (BM&FBOVESPA) entre janeiro de 2010 até dezembro de 2015. Os resultados mostram que modelos relativamente mais complexos como redes neurais não necessariamente apresentam melhor desempenho se comparados a modelos mais simples, e também mostram que a classificação relativa muda conforme variam as medidas de ajuste e/ou horizonte de previsão além de vantagens associadas a combinação de diversos modelos.This study compared the predictive performance between neural network models and exponential smoothing, using daily data of live cattle future price (BM&FBOVESPA) from January 2010 to December 2015. The results show that relatively more complex models like neural networks do not necessarily display better performance compared to simpler ones. Results also shows that relative classification changes with respect to adjust measures and/or forecast horizons changes besides advantages achieved by model combinaion.
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Le, Fleur Celeste Catherine. "Comparing the BDI II and the HADS (HADS-D) as a screening tool for depression amongst HIV infected individuals attending a public health clinic." Thesis, University of the Western Cape, 2011. http://etd.uwc.ac.za/index.php?module=etd&action=viewtitle&id=gen8Srv25Nme4_2733_1363786537.
Full textAbstract:
This study utilised secondary data from a larger study that looked at individuals that are already infected by HIV which is entitled Implicative personal dilemmas and cognitive conflicts in health decision making in HIV positive adults and adults with AIDS. The primary aim of the larger study was to examine the cognitive construction of the individual and how they utilised their individual resources to construct who they are and how they perceived the difficulties and challenges that they face and the decisions they make regarding their health. HIV and AIDS is a debilitating disease and it affects millions worldwide. South Africa, presently, has the largest burden of this disease with those between the ages of 15 &ndash
49 years of age being most affected. As previously
mentioned the decisions that individuals make can impact on their health. Decisions to take necessary precautions such as protected sex during sexual intercourse can decrease the
progression of the disease. Decisions made regarding abstinence of risky behaviour as well as being committed to taking medication could also positively impact health. People living with HIV and AIDS find it
difficult to adjust to the challenges that this disease presents. Depression is often experienced due to the changes in self image and perception. Studies show that
females are twice more likely to experience depression than men. There has however been no conclusive evidence showing the reason for this, however, the perception of stress based on
gender could shed some light on this matter and how these perceptions can increase the likelihood of women being more vulnerable to depression. Due to the limitation of this study, it will
only look at depression as it relates to HIV and AIDS. Psychological problems such as depression can hamper the adjustment process and the effect of depression is evident in that it can lower the CD 4 + cells. Not only are those
living with HIV and AIDS affected by depression, but they also have a lifetime prevalence to depression. It is important to have an effective screening tool for depression so that the detection of this
disease can be made and effective treatment can be implemented to enhance health. The sample consisted of 113 adult participants that have already been diagnosed with HIV and AIDS. The
primary aim of this study was to compare the Beck&rsquo
s Depression Inventory II (BDI II) and the Hospital Anxiety and Depression Scale &ndash
(the Depression component) (HADS-D) as a screening tool
for depression. Exploratory Factor Analysis revealed a 5 factor structure which accounted for 60.14 % of the total variance. The HADS yielded one factor accounting for 14.33% of total variance. The BDI II has proven to be more a reliable measure of depression with 0.89 according to the Cronbach&rsquo
s Alpha co efficient opposed to 0.375 as per the HADS-D. The secondary aim was to establish
the sociodemographic and disease profiles of the participants under study.
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Chang, Su Eun. "A bid-rent network equilibrium model." Thesis, University College London (University of London), 2004. http://discovery.ucl.ac.uk/1446893/.
Full textAbstract:
This thesis discusses the development of a new model for investigating the relationship between transport and the location of activities. The research consists of three stages. In the first phase, the structural features of the relationship, which are the characteristics of locations, the decision-making processes of households, and the interaction between transport and land-use, are identified. Existing approaches are reviewed using these three components. The review shows that no existing framework satisfactorily represents the requirements in modelling the relationship. Secondly, a bid-rent network equilibrium model is developed. The modelling is considered in terms of competition for locations. Difficulties in analysing the unique characteristics of locations, namely heterogeneity and indivisibility, are discussed. A hedonic interpretation is incorporated to overcome the difficulties. The model represents the decision-making processes of households using the framework of an n-player non-cooperative game. The Nash equilibrium for this game is defined. The game is accompanied by the systematic interactions between transport and land-use. A mutual adjustment process addresses these interactions. A bi-level mathematical programme is suggested to embody the three components. The resulting formulation is interpreted as an oligopolistic Cournot game, which is an approximation of the n-player non- cooperative game. The functional relationship between the decision variables of the upper and lower levels in the bi-level model produces endogenously-determined transport impedance and locational attractiveness. The model incorporates a multiclass framework to consider interclass interactions, which establishes a multiclass bid-rent network equilibrium model. A heuristic algorithm is provided for the solution-finding technique of the bid-rent network equilibrium model. The algorithm combines a path-based routine for calculating the equilibrium solution to the lower level with the Newton-Raphson procedure for estimating the parameters of the hedonic-based stochastic bid-rent function in the upper level. The operation of the algorithm is examined using simple numerical examples. The final stage is an application of the bid-rent network equilibrium model to a real network. A medium sized city is chosen for the case study. The objective of the third stage is to demonstrate the ability of the model to investigate the relationship between transport and the location of activities. A base run and two policy runs are simulated. The base run means a simulation conducted using surveyed data. The policy runs represents the introduction of a congestion charge and the release of land for housing development. Class specific spatial behaviour is obtained. The behaviour is demonstrated using network performance indices representing transport impedance and locational attractiveness. Some policy implications of the simulation are presented.
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Larson, Dana Elizabeth. "Feeling Sad? Maybe You are Just Uncertain! A Predictive Test for Depression." TopSCHOLAR®, 2013. http://digitalcommons.wku.edu/theses/1318.
Full textAbstract:
The current study examined the relationship between depression and uncertainty within the stress-diathesis model. Depression is a mental health disorder that is wide spread within our society. However, few causes of this disease have been able to be identified. Studies in uncertainty have shown that it is a major stressor in day-to-day life. Previous research has shown that individuals with high levels of uncertainty show higher levels of depression. The stress-diathesis model, a model originally developed to explain differences in development of schizophrenia, provides a theoretically meaningful way to combine these two concepts. The model states that a person who is likely to develop a disease has an internal mechanism, a diathesis, that will be triggered upon presentation of a stressor. This study tested the idea that uncertainty can be used as a stressor to activate diathesis within an individual, aiding in the prediction of depression. In total, 163 participants were randomly assigned one of three conditions, an uncertainty threat, an affirmation condition, and a control condition. Participants were given pre and post independent variable measures of depression and anxiety. Findings suggest that uncertainty activated negative emotions differentially within the participants, resulting in higher levels of negative affects after the uncertainty threat, especially for participants who already scored relatively higher on depression indicators. These results hint at a possible understanding of why depression rates and diagnosis rates of mental health issues rise during economic downturn and other times of strong uncertainty.