Uma extensão temporal a teoria das coberturas parcimoniosas

Orientador: Jacques WainerDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Matematica Estatistica e Ciencia da ComputaçãoResumo: Nesta dissertação propõe-se uma extensão temporal à Teoria das Coberturas Parcimoniosas. Esta teoria provê um fundamento teórico ao processo de raciocínio diagnóstico, como um raciocínio abdutivo baseado nos modelos que associam causas à suas conseqüências (ou doenças com seus sinais e sintomas). A extensão temporal proposta para a Teoria das Coberturas Parcimoniosas possibilita associar a cada doença a evolução temporal dos seus sinais e sintomas. A eliminação de hipóteses temporalmente inconsistentes minimiza uma das maiores limitações da Teoria das Coberturas Parcimoniosas: a teoria pode incluir um grande número de hipóteses alternativas. Além do mais, a inclusão de aspectos temporais a uma extensão da teoria que inclua informações probabilísticas também elimina o problema de rejeições incorretas de hipóteses quando um sintoma necessário não estiver presente. A extensão temporal proposta é aplicada a um problema de diagnóstico médico em que o tempo é importante na diagnose. Os resultados obtidos foram bastante satisfatórios, como a construção rápida da base de conhecimento, a eliminação significativa do número de hipóteses e a redução do tempo gasto na obtenção da solução do problema. Finalmente, são apresentadas as contribuições, limitações e extensões futuras desta dissertaçãoAbstract: In this work we propose a temporal extension to the Parsimonious Covering Theory. This theory provides a theoretical foundation for the diagnostic reasoning process as an abdutive reasonig based on models that associate causes with their consequences (or diseases and their symptoms). Our temporal extension of the Parsimonious Covering Theory allows one to associate to a disease a temporal evolution of symptoms. The elimination of temporally inconsistent hypothesis minimizes one of the greatest limitation of the Parsimonious Covering Theory: the theory may include a large number of alternative hypothesis. Furthermore, the inclusion of temporal aspects to an extension of this theory that includes probabilistic information also eliminates the problem of incorrectly rejecting hypothesis if a necessary symptom has not yet ocurred. Finally, the limitations of the representation formalism and the problems with the temporal reasoning in a diagnostic system are also describedMestradoMestre em Ciência da Computaçã

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