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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Analýza síly testů hypotéz / Statistical tests power analysis

Kubrycht, Pavel January 2016 (has links)
This Thesis deals with the power of a statistical test and the associated problem of determining the appropriate sample size. It should be large enough to meet the requirements of the probabilities of errors of both the first and second kind. The aim of this Thesis is to demonstrate theoretical methods that result in derivation of formulas for minimum sample size determination. For this Thesis, three important probability distributions have been chosen: Normal, Bernoulli, and Exponential.
2

Detec??o de isquemia card?aca em diferentes deriva??es utilizando redes neurais artificiais e um classificador h?brido Gaussiano e Bayesiano

Schutte, Wallinson Oliveira 29 November 2017 (has links)
Submitted by Raniere Barreto (raniere.barros@ufvjm.edu.br) on 2018-04-13T17:44:56Z No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) wallinson_oliveira_schutte.pdf: 2955879 bytes, checksum: 7d21ec1707fa5cf82b0b96642d27fa03 (MD5) / Rejected by Rodrigo Martins Cruz (rodrigo.cruz@ufvjm.edu.br), reason: Verificar refer?ncia e keywords. on 2018-04-20T15:00:26Z (GMT) / Submitted by Raniere Barreto (raniere.barros@ufvjm.edu.br) on 2018-05-15T18:16:15Z No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) wallinson_oliveira_schutte.pdf: 2955879 bytes, checksum: 7d21ec1707fa5cf82b0b96642d27fa03 (MD5) / Approved for entry into archive by Rodrigo Martins Cruz (rodrigo.cruz@ufvjm.edu.br) on 2018-05-15T19:38:43Z (GMT) No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) wallinson_oliveira_schutte.pdf: 2955879 bytes, checksum: 7d21ec1707fa5cf82b0b96642d27fa03 (MD5) / Made available in DSpace on 2018-05-15T19:38:43Z (GMT). No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) wallinson_oliveira_schutte.pdf: 2955879 bytes, checksum: 7d21ec1707fa5cf82b0b96642d27fa03 (MD5) Previous issue date: 2017 / O presente estudo prop?e o desenvolvimento de duas ferramentas para se fazer a classifica??o de batimentos card?acos a fim de detectar a Isquemia Card?aca. Uma baseada em propriedades da Distribui??o Normal e Teorema de Bayes e a outra baseada em Redes Neurais Artificiais. Utilizando o banco de dados Long-Term ST Database, foi efetuado um filtro de dados, que foram agrupados pelas seguintes deriva??es: A-S, E-S, A-I, ML2, MV2, ML3, V4 e V5. Por meio dos algoritmos propostos, implementados por interm?dio da Linguagem de Programa??o PHP, p?de-se verificar a deriva??o mais prop?cia a se detectar essa doen?a. Foi poss?vel observar as deriva??es V5 e A-S com melhores resultados utilizando-se o algoritmo h?brido. Na V5, foi obtido Sensibilidade de 100%, Especificidade de 97%, Valor Preditivo Positivo de 95.89% e Valor Preditivo Negativo de 100% e, na A-S, valores de 99.22%, 99.99%, 99.99% e 99.61% para Sensibilidade, Especificidade, Valor Preditivo Positivo e Valor Preditivo Negativo. O algoritmo de Redes Neurais Artificiais apresentou o melhor resultado para deriva??o A-S com 99.98%, 100%, 100% e 99.99% para Sensibilidade, Especificidade, Valor Preditivo Positivo e Valor Preditivo Negativo respectivamente. Tamb?m foi calculado o intervalo de confian?a para propor??es populacionais com 95% de confian?a, a fim de se estabelecer n?veis de precis?o das bases utilizadas. / Disserta??o (Mestrado Profissional) ? Programa de P?s-Gradua??o em Tecnologia, Sa?de e Sociedade, Universidade Federal dos Vales do Jequitinhonha e Mucuri, 2017. / The present study proposes the development of two tools to classify heart beats in order to detect cardiac ischemia. One based on properties of Normal Distribution and Bayes' Theorem and the other based on Artificial Neural Networks. Using the Long-Term ST Database, a data filter was performed, which was grouped by the following derivations: A-S, E-S, A-I, ML2, MV2, ML3 and V4, V5. By means of the algorithms proposed, implemented through the PHP Programming Language, we could verify the most favorable derivation to detect this disease. It was possible to observe the V5 and A-S leads with better results using the hybrid algorithm. In V5, 100% sensitivity, 97% specificity, 95.89% positive predictive value and 100% negative predictive value were obtained, and in A-S, values of 99.22%, 99.99%, 99.99% and 99.61% for sensitivity, specificity, positive predictive value, and negative predictive value. The algorithm of Artificial Neural Networks presented the best result for A-S derivation with 99.98%, 100%, 100% and 99.99% for sensitivity, specificity, positive predictive value and negative predictive value respectively. We also calculated the confidence interval for population proportions with 95% confidence in order to establish precision levels of the bases used. / El presente estudio propone el desarrollo de dos herramientas para la clasificaci?n de los latidos del coraz?n con el fin de detectar la isquemia card?aca. Uno basado en las propiedades de la Distribuci?n Normal y el Teorema de Bayes y el otro basado en las Redes Neuronales Artificiales. Utilizando la base de datos Long-Term ST Database, se llev? a cabo un filtro de datos, que fueron agrupados seg?n las siguientes derivaciones: a-S, E, S, A-I, ML2, MV2, ML3, V4 y V5. Por medio de los algoritmos propuestos, implementado a trav?s del lenguaje de programaci?n PHP, pudimos comprobar la derivaci?n m?s favorable para detectar esta enfermedad. Fue posible observar las derivaciones V5 y A-S con mejores resultados utilizando el algoritmo h?brido. En V5 se obtuvo una sensibilidad del 100%, uma especificidad del 97%, 95.89% de valor predictivo positivo y 100% de valor predictivo negativo y en A-S, valores de 99.22%, 99.99%, 99.99% y 99.61% para la sensibilidad, especificidad, valor predictivo positivo, y valor predictivo negativo respectivamente. El algoritmo de Redes Neuronales Artificiales present? el mejor resultado para la derivaci?n A-S con 99.98%, 100%, 100% y 99.99% para la sensibilidad, especificidad, valor predictivo positivo y valor predictivo negativo, respectivamente. Tambi?n fue calculado el intervalo de confianza para proporciones de las poblaciones con 95% de confianza con el fin de establecer los niveles de confianza precisi?n de las bases utilizadas

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