Mathematical decomposition technique applied to the probabilistic power flow problem

In this paper a framework based on the decomposition of the first-order optimality conditions is described and applied to solve the Probabilistic Power Flow (PPF) problem in a coordinated but decentralized way in the context of multi-area power systems. The purpose of the decomposition framework is to solve the problem through a process of solving smaller subproblems, associated with each area of the power system, iteratively. This strategy allows the probabilistic analysis of the variables of interest, in a particular area, without explicit knowledge of network data of the other interconnected areas, being only necessary to exchange border information related to the tie-lines between areas. An efficient method for probabilistic analysis, considering uncertainty in n system loads, is applied. The proposal is to use a particular case of the point estimate method, known as Two-Point Estimate Method (TPM), rather than the traditional approach based on Monte Carlo simulation. The main feature of the TPM is that it only requires resolve 2n power flows for to obtain the behavior of any random variable. An iterative coordination algorithm between areas is also presented. This algorithm solves the Multi-Area PPF problem in a decentralized way, ensures the independent operation of each area and integrates the decomposition framework and the TPM appropriately. The IEEE RTS-96 system is used in order to show the operation and effectiveness of the proposed approach and the Monte Carlo simulations are used to validation of the results. © 2011 IEEE.

An application of a modified constructive heuristic algorithm to transmission expansion planning

Transmission expansion planning (TEP) is a non-convex optimization problem that can be solved via different heuristic algorithms. A variety of classical as well as heuristic algorithms in literature are addressed to solve TEP problem. In this paper a modified constructive heuristic algorithm (CHA) is proposed for solving such a crucial problem. Most of research papers handle TEP problem by linearization of the non-linear mathematical model while in this research TEP problem is solved via CHA using non-linear model. The proposed methodology is based upon Garver's algorithm capable of applying to a DC model. Simulation studies and tests results on the well known transmission network such as: Garver and IEEE 24-bus systems are carried out to show the significant performance as well as the effectiveness of the proposed algorithm. © 2011 IEEE.

Domain reduction using GRASP construction phase for transmission expansion planning problem

This paper proposes a new strategy to reduce the combinatorial search space of a mixed integer linear programming (MILP) problem. The construction phase of greedy randomized adaptive search procedure (GRASP-CP) is employed to reduce the domain of the integer variables of the transportation model of the transmission expansion planning (TM-TEP) problem. This problem is a MILP and very difficult to solve specially for large scale systems. The branch and bound (BB) algorithm is used to solve the problem in both full and the reduced search space. The proposed method might be useful to reduce the search space of those kinds of MILP problems that a fast heuristic algorithm is available for finding local optimal solutions. The obtained results using some real test systems show the efficiency of the proposed method. © 2012 Springer-Verlag.

Relações entre os conhecimentos, as atitudes e a confiança dos alunos do curso de licenciatura em Matemática em resolução de problemas geométricos

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Implantação de sistemas de segurança e saúde no trabalho em empresas fabricantes de baterias automotivas

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

A resolução de problemas na licenciatura em Matemática: análise de um processo de formação no contexto do estágio curricular supervisionado

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Análise do processo de gestão de portfólio de projetos seis sigma em indústrias brasileiras do setor automotivo

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

PARFOR e a formação inicial dos professores: um estudo sobre a confiança, as atitudes e as estratégias em relação à resolução de problemas

The mathematical problem solving is very important in the student's school career, leading him to develop his creativity and self-confidence. The way the teacher explains specific content may interfere in the student learning. Some researches show that the teacher trust and his problem solving rapport lead to a more satisfying job. This research focused on students of the course PARFOR at UNESP Bauru. This work was performed in order to investigate the affinity, trust and attitudes toward mathematical problem solving, the performance from who have positive and negative attitudes and the results that may be generated during class

Um estudo sobre a resolução de problemas e suas relações com a afetividade

This research aims at examining the relationship between the performance of elementary school students Cycle I in problem solving and attitudes toward mathematics. For this, a research was conducted at a state school in the city of Bauru which was selected for convenience. Participants were randomly selected consisting of 75 students, of whom 21 were third years and 57 were of three classes of fifth year. The instruments used for data collection were: a informative questionnaire to characterize the students in age, grade, favorite subjects and the least liked, among others, an attitude scale, Likert type, to examine the attitudes toward mathematics; a interviews with 11 selected students according to scores on the attitudes and mathematical problems to be solved through the method of thinking aloud. The results showed that the major difficulties encountered by students in solving problems were: to understand the problems, formalizing the reasoning, recognize in the problem the algorithms needed for its resolution, make calculations with decimal numbers, do combinatorics, using the sum of equal portions instead of multiplying, self-confidence and autonomy in what he was doing, and others; participants with positive attitudes towards mathematics showed greater confidence to solve problems as well as a greater understanding on what was required by them, but were not detected significant relation between the attitudes and performance, since it was unfavorable

Masticatory performance of complete denture wearers after using two adhesives: a crossover randomized clinical trial

Statement of problem Masticatory performance analysis of conventional complete denture wearers who use denture adhesives is scarce in the dental literature. Purpose The purpose of this study was to assess the effect of the use of 2 denture adhesives on the masticatory performance of conventional complete denture wearers by means of a crossover study. Material and methods Forty individuals who were edentulous received new maxillary and mandibular complete dentures, and, after an adaptation period, were submitted to masticatory performance analysis without denture adhesive (control). The participants were randomly divided and assigned to 2 protocols: protocol 1, denture adhesive 1 (Ultra Corega cream tasteless) use during the first 15 days, followed by no use of denture adhesive over the next 15 days (washout), and then use of denture adhesive 2 (Ultra Corega powder tasteless) for 15 days; protocol 2, denture adhesive 2 (Ultra Corega powder tasteless) use during the first 15 days, followed by no use of denture adhesive during the next 15 days (washout), and then use of denture adhesive 1 (Ultra Corega cream tasteless) for 15 days. The masticatory performance was assessed immediately after the use of denture adhesive by means of the sieve method, in which participants were instructed to deliberately chew 5 almonds for 20 chewing strokes. Masticatory performance was calculated by the weight of comminuted material that passed through the sieves. Data were analyzed by a 1-way ANOVA for paired samples and the multiple comparison of means by using the Bonferroni test (α=.05). Results A significant increase in masticatory performance was noted after using the Ultra Corega cream (mean, 32.6%) and Ultra Corega powder (mean, 31.2%) when compared with the control group (mean, 19.8%) (P<.001). No significant difference was found between the 2 denture adhesives evaluated. Conclusion The use of denture adhesive improved the masticatory performance of conventional complete denture wearers. No difference was found in masticatory performance with the use of cream or powder denture adhesive.

Masticatory performance of complete denture wearers after using two adhesives: a crossover randomized clinical trial

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Programação no ensino de matemática utilizando Processing 2: Um estudo das relações formalizadas por alunos do ensino fundamental com baixo rendimento em matemática

Pós-graduação em Educação para a Ciência - FC

Optimal attitude corrections for cylindrical spacecraft

A first order analytical model for optimal small amplitude attitude maneuvers of spacecraft with cylindrical symmetry in an elliptical orbits is presented. The optimization problem is formulated as a Mayer problem with the control torques provided by a power limited propulsion system. The state is defined by Seffet-Andoyer's variables and the control by the components of the propulsive torques. The Pontryagin Maximum Principle is applied to the problem and the optimal torques are given explicitly in Serret-Andoyer's variables and their adjoints. For small amplitude attitude maneuvers, the optimal Hamiltonian function is linearized around a reference attitude. A complete first order analytical solution is obtained by simple quadrature and is expressed through a linear algebraic system involving the initial values of the adjoint variables. A numerical solution is obtained by taking the Euler angles formulation of the problem, solving the two-point boundary problem through the shooting method, and, then, determining the Serret-Andoyer variables through Serret-Andoyer transformation. Numerical results show that the first order solution provides a good approximation to the optimal control law and also that is possible to establish an optimal control law for the artificial satellite's attitude. (C) 2003 COSPAR. Published by Elsevier B.V. Ltd. All rights reserved.

Inteligência artificial e teoria de resolução de problemas

Este artigo é uma tentativa de delinear as principais características da pesquisa numa nova área de estudos a chamada Inteligência Artificial (AI). Os itens 1 e 2 constituem um rápido histórico da AI e seus pressupostos básicos. O item 3 trata da teoria de resolução de problemas, desenvolvida por A. Newell e H. Simon. O item 4 procura mostrar a relevância da AI para a Filosofia, em especial para a filosofia da Mente e para a Teoria do Conhecimento.

Meio ambiente e enfermagem: suas interfaces e inserção no ensino de graduação

A degradação ambiental vem modificando nosso cenário de forma acelerada e interferindo negativamente no processo saúde-doença de toda a comunidade. No entanto, o meio ambiente vem sendo concebido como um simples cenário, algo externo ao ser humano, não onde estamos inseridos e no qual acontecem suas interações e inter-relações. A complexidade dos problemas ambientais clama pela adoção de medidas que superem práticas assistencialistas, levando à adoção de práticas transdisciplinares que avancem na promoção da saúde. Neste artigo procura-se discutir, nesta perspectiva, a necessidade de inserção nos cursos de graduação em saúde a temática saúde e meio ambiente, adotando como exemplo um curso de enfermagem do interior paulista que inseriu uma disciplina relacionada ao tema. Analisa também o papel do enfermeiro na relação com o meio ambiente segundo a representação social dos alunos, trabalhada a partir do Discurso do Sujeito Coletivo. Nota-se que é fundamental discutir essa temática ambiental entre os profissionais da saúde, a fim de que eles se empoderem desse conhecimento e consigam identificar problemas relacionados à questão ambiental, propondo ações resolutivas e preventivas, juntamente com a comunidade, procurando amenizar os riscos ambientais a que todos estão expostos. Reforça-se a profundidade do papel dos profissionais de saúde diante dos problemas ambientais, buscando a saúde em uma perspectiva ampliada de promoção da saúde.