966 resultados para Interdisciplinary
Resumo:
The fabrication of heavy-duty printer heads involves a great deal of grinding work. Previously in the printer manufacturing industry, four grinding procedures were manually conducted in four grinding machines, respectively. The productivity of the whole grinding process was low due to the long loading time. Also, the machine floor space occupation was large because of the four separate grinding machines. The manual operation also caused inconsistent quality. This paper reports the system and process development of a highly integrated and automated high-speed grinding system for printer heads. The developed system, which is believed to be the first of its kind, not only produces printer heads of consistently good quality, but also significantly reduces the cycle time and machine floor space occupation.
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This work investigated listeners` sense of the temporal expression of tonal modulation. One experiment described the effects on retrospective reproductions of sudden and gradual modulations to close and distant keys. The results showed that modulations elicit time underestimations as an inverse function of interkey distances, with a major impact for sudden modulations. A proposed vectorial model - ""Expected Development Fraction"" (EDF) - describes the development of expectations when an interkey distance is traversed during a certain time interval. This expected development is longer than the perceived duration, leading to underestimation of the time.
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The image reconstruction using the EIT (Electrical Impedance Tomography) technique is a nonlinear and ill-posed inverse problem which demands a powerful direct or iterative method. A typical approach for solving the problem is to minimize an error functional using an iterative method. In this case, an initial solution close enough to the global minimum is mandatory to ensure the convergence to the correct minimum in an appropriate time interval. The aim of this paper is to present a new, simple and low cost technique (quadrant-searching) to reduce the search space and consequently to obtain an initial solution of the inverse problem of EIT. This technique calculates the error functional for four different contrast distributions placing a large prospective inclusion in the four quadrants of the domain. Comparing the four values of the error functional it is possible to get conclusions about the internal electric contrast. For this purpose, initially we performed tests to assess the accuracy of the BEM (Boundary Element Method) when applied to the direct problem of the EIT and to verify the behavior of error functional surface in the search space. Finally, numerical tests have been performed to verify the new technique.
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In this work we study the existence and regularity of mild solutions for a damped second order abstract functional differential equation with impulses. The results are obtained using the cosine function theory and fixed point criterions. (C) 2009 Elsevier Ltd. All rights reserved.
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This work deals with the existence of mild solutions for a class of impulsive functional differential equations of the neutral type associated with the family of linear closed (not necessarily bounded) operators {A(t) : t is an element of 1}. (C) 2009 Elsevier Ltd. All rights reserved.
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This paper proposes the use of the q-Gaussian mutation with self-adaptation of the shape of the mutation distribution in evolutionary algorithms. The shape of the q-Gaussian mutation distribution is controlled by a real parameter q. In the proposed method, the real parameter q of the q-Gaussian mutation is encoded in the chromosome of individuals and hence is allowed to evolve during the evolutionary process. In order to test the new mutation operator, evolution strategy and evolutionary programming algorithms with self-adapted q-Gaussian mutation generated from anisotropic and isotropic distributions are presented. The theoretical analysis of the q-Gaussian mutation is also provided. In the experimental study, the q-Gaussian mutation is compared to Gaussian and Cauchy mutations in the optimization of a set of test functions. Experimental results show the efficiency of the proposed method of self-adapting the mutation distribution in evolutionary algorithms.
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In this paper we study the existence of mild solutions for a class of first order abstract partial neutral differential equations with state-dependent delay. (C) 2008 Elsevier Ltd. All rights reserved.
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We show the results in Chalishajar [Controllability of mixed Volterra-Fredholm-type integro-differential systems in Banach space, J. Franklin Inst. 344(1) (2007) 12-21] and Chang and Chalishajar [Controllability of mixed Volterra-Fredholm type integro-differential systems in Banach space, J. Franklin Inst., doi:10.1016/j. jfranklin.2008.02.002] are only valid for ordinary differential control systems. As a result the examples provided cannot be recovered as applications of the abstract results. (C) 2008 The Franklin Institute. Published by Elsevier Ltd. All rights reserved.
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We study the existence of mild solutions for a class of impulsive neutral functional differential equation defined on the whole real axis. Some concrete applications to ordinary and partial neutral differential equations with impulses are considered. (C) 2010 Elsevier Ltd. All rights reserved.
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In order to refute the interpretation that racial democracy in Brazil has simply been an illusion or ruse of white supremacy, the authors analyze the participation of Black leaders in the elaboration of the Brazilian national imaginary in the 1940s. They argue that during that period, racial democracy was a powerful instrument for mobilizing Blacks as well, whether as nationalists or anti-racists. The authors explore one of the most important sources through which this ideology was forged by a key figure of the Black intelligentsia, Abdias do Nascimento, with his column in the Diario Trabalhista [Laborite Daily] entitled ""Problems and Aspirations of Black Brazilians"". In this column, Nascimento published dozens of interviews with Black leaders and common people that demonstrate the foundations, principles, and interests involved in the construction of a racial democracy.
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In an article in this journal, Boeckx & Hornstein (2006a) present data from Brazilian Portuguese (BP) as an argument in favor of the Movement Theory of Control (MTC). In this reply, I show that the data presented by those authors do not necessarily argue for a movement analysis of BP finite subjects nor of nonfinite control. I also show that BP provides arguments against the MTC when inflected infinitives are considered. Inflected infinitives may be used in BP in partial control structures, which makes it explicit that a singular matrix argument may control a syntactically plural null subject and shows that these two positions cannot be related by movement. Additionally, I show that the MTC makes the wrong predictions when a language with inflected infinitives is considered.
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This article presents the results of a comparative study on socio-spatial structures in Rio de Janeiro and Sao Paulo in 2000. We drew on data from the national Demographic Census by weighted areas to construct the Erikson, Goldthorpe, and Portocarrero (EGP) classification and the International Socio-Economic Index (ISEI), both widely used in social stratification studies. This information was then submitted to group analyses for the two cities, allowing comparison of the presence of social groups in each city. Next, using spatial statistics, we assessed the spatial distribution of the socio-economic classes and the presence of social segregation in the two metropolitan areas. The results suggest the presence of strong similarity between the social structures in the two cities, also marked by similarly intense patterns of social segregation at the metropolitan level.
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The solidification of intruded magma in porous rocks can result in the following two consequences: (1) the heat release due to the solidification of the interface between the rock and intruded magma and (2) the mass release of the volatile fluids in the region where the intruded magma is solidified into the rock. Traditionally, the intruded magma solidification problem is treated as a moving interface (i.e. the solidification interface between the rock and intruded magma) problem to consider these consequences in conventional numerical methods. This paper presents an alternative new approach to simulate thermal and chemical consequences/effects of magma intrusion in geological systems, which are composed of porous rocks. In the proposed new approach and algorithm, the original magma solidification problem with a moving boundary between the rock and intruded magma is transformed into a new problem without the moving boundary but with the proposed mass source and physically equivalent heat source. The major advantage in using the proposed equivalent algorithm is that a fixed mesh of finite elements with a variable integration time-step can be employed to simulate the consequences and effects of the intruded magma solidification using the conventional finite element method. The correctness and usefulness of the proposed equivalent algorithm have been demonstrated by a benchmark magma solidification problem. Copyright (c) 2005 John Wiley & Sons, Ltd.
Resumo:
When and how did the Brazilian Black movement appear in the social sciences? What are the theoretical approaches and explanations for the 20th century emergence and development? This article will address these principal issues by analyzing studies that have taken on the topic of collective black mobilization from various disciplinary vantage points, particularly, Sociology, History and Anthropology.