2 resultados para Bivariate Bath-tub Shaped Failure Rate

em Universidade Federal do Rio Grande do Norte(UFRN)


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This essay proposes to research the success and failure in Education for Youth and Adults (known as EJA), based on the approval, failure and evasion rates in public schools belonging to the city of Natal, RN. Reflecting upon the reasons why some pupils from this program were dropping out of school while others kept on studying was a necessity. Therefore, we seek to know these subjects and their school environment. In the search this data, we set off by approaching the EJA politics, going through a historical path, highlighting significant facts to Brazilian and Natal history. While bringing together the pieces of information for this essay, we were lead to the State and City Education Department, in search of approval, failure and evasion rates from the year 2009. Based on these rates, two schools have been chosen: the first with a high failure rate and the second with a failure rate lower than the city average. The schools work was researched throughout the year 2010, through interviews with pupils, teachers, managers and employees; school files analysis; the analysis of files the establish the rules for EJA programs in the city of Natal. Nethertheless, this essay points to inner and outer factors which might come to contribute to the failure or success of pupils from the researched schools, emphasizing that the difference between those are in the team work present in the school with low failure rate

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The static and cyclic assays are common to test materials in structures.. For cycling assays to assess the fatigue behavior of the material and thereby obtain the S-N curves and these are used to construct the diagrams of living constant. However, these diagrams, when constructed with small amounts of S-N curves underestimate or overestimate the actual behavior of the composite, there is increasing need for more testing to obtain more accurate results. Therewith, , a way of reducing costs is the statistical analysis of the fatigue behavior. The aim of this research was evaluate the probabilistic fatigue behavior of composite materials. The research was conducted in three parts. The first part consists of associating the equation of probability Weilbull equations commonly used in modeling of composite materials S-N curve, namely the exponential equation and power law and their generalizations. The second part was used the results obtained by the equation which best represents the S-N curves of probability and trained a network to the modular 5% failure. In the third part, we carried out a comparative study of the results obtained using the nonlinear model by parts (PNL) with the results of a modular network architecture (MN) in the analysis of fatigue behavior. For this we used a database of ten materials obtained from the literature to assess the ability of generalization of the modular network as well as its robustness. From the results it was found that the power law of probability generalized probabilistic behavior better represents the fatigue and composites that although the generalization ability of the MN that was not robust training with 5% failure rate, but for values mean the MN showed more accurate results than the PNL model