Análise e desenvolvimento de algoritmos eficientes de programação linear para o problema de planejamento de sistemas de transmissão a longo prazo

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

Fluxo de potência ótimo em sistemas multimercados através de um algorítmo evolutivo multiobjetivo

Pós-graduação em Engenharia Elétrica - FEIS

Uma contribuição para a otimização de portfólios de séries heteroscedásticas usando projeto de experimento de misturas: uma abordagem do desirability aplicada a modelos

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Optimization of annatto (Bixa orellana L.) drying in fixed bed

ABSTRACT: The drying of annatto seeds (Bixa orellana L.), red piave cultivate, was studied in a fixed bed dryer. The best conditions were estimated to minimize the loss of coloring and to obtain final moisture of the seeds in appropriate levels to its conservation and maintenance of quality. The quantification of the influence of entrance variables in the final contents of bixin and moisture seeds and the identification of the optimal point was performed through the techniques of factorial design, response surfaces methodology, canonical analysis and desirability function. It was verified that the final moisture of the seeds may be estimated by a second-order polynomial model and that the final content of bixin is only significantly influenced by the time of drying being described properly by a linear model, for the seeds used in this study.

Aeroelastic stability analysis using linear matrix inequalities

The present work describes an alternative methodology for identification of aeroelastic stability in a range of varying parameters. Analysis is performed in time domain based on Lyapunov stability and solved by convex optimization algorithms. The theory is outlined and simulations are carried out on a benchmark system to illustrate the method. The classical methodology with the analysis of the system's eigenvalues is presented for comparing the results and validating the approach. The aeroelastic model is represented in state space format and the unsteady aerodynamic forces are written in time domain using rational function approximation. The problem is formulated as a polytopic differential inclusion system and the conceptual idea can be used in two different applications. In the first application the method verifies the aeroelastic stability in a range of air density (or its equivalent altitude range). In the second one, the stability is verified for a rage of velocities. These analyses are in contrast to the classical discrete analysis performed at fixed air density/velocity values. It is shown that this method is efficient to identify stability regions in the flight envelope and it offers promise for robust flutter identification.

Particle swarm optimization aplicada ao planejamento da expansão de sistemas de transmissão

Pós-graduação em Engenharia Elétrica - FEIS

Otimização de planos de manutenções de componentes de sistemas de distribuição de energia elétrica centrados em confiabilidade

Pós-graduação em Engenharia Elétrica - FEIS

Avaliação experimental de um sistema não linear para extração de energia através de vibrações utilizando material piezelétrico

Pós-graduação em Engenharia Mecânica - FEIS

Discovering promising regions to help global numerical optimization algorithms

We have developed an algorithm using a Design of Experiments technique for reduction of search-space in global optimization problems. Our approach is called Domain Optimization Algorithm. This approach can efficiently eliminate search-space regions with low probability of containing a global optimum. The Domain Optimization Algorithm approach is based on eliminating non-promising search-space regions, which are identifyed using simple models (linear) fitted to the data. Then, we run a global optimization algorithm starting its population inside the promising region. The proposed approach with this heuristic criterion of population initialization has shown relevant results for tests using hard benchmark functions.

The influence of self-weight of elastic 2D structures in topology optimization via numerical technique Smooth Evolutionary Structural Optimization (SESO)

This paper deals with topology optimization in plane elastic-linear problems considering the influence of the self weight in efforts in structural elements. For this purpose it is used a numerical technique called SESO (Smooth ESO), which is based on the procedure for progressive decrease of the inefficient stiffness element contribution at lower stresses until he has no more influence. The SESO is applied with the finite element method and is utilized a triangular finite element and high order. This paper extends the technique SESO for application its self weight where the program, in computing the volume and specific weight, automatically generates a concentrated equivalent force to each node of the element. The evaluation is finalized with the definition of a model of strut-and-tie resulting in regions of stress concentration. Examples are presented with optimum topology structures obtaining optimal settings. (C) 2012 CIMNE (Universitat Politecnica de Catalunya). Published by Elsevier Espana, S.L.U. All rights reserved.

Controle de qualidade em radioterapia: dosimetria de fótons em acelerador linear – Mevatron MXT

The treatment of a tumor with ionizing radiation is an ongoing process with well differentiated stages. These ones include the tumor diagnosis and location, the decision on the treatment strategy, the absorbed dose planning and calculation, the treatment administration, the absorbed dose verification and the evaluation of results in short and long terms. The quality of a radiotherapy procedure is closely linked to factors that may be classified as clinical, such as the diagnosis, the tumor location, the treatment strategy chosen and the continuous treatment reassessment; dosimetric or physical, such as the uncertainty in the dose calculation, its optimization and verification, the suitability of the equipment to provide a radiation beam consistent with the treatment planning; finally, others which are related to the practical application of radiotherapy treatment and the handling of the patient. In order to analyze the radiotherapy quality, one should realize that the three aspects (medical, physical or dosimetric and practical application) should be considered in a combined way. This means that numerous actions of the radiotherapists, medical physicists and technicians in radiotherapy should be held jointly and their knowledge level will significantly affect the treatment quality. In this study, the main physical parameters used in dosimetry are defined as well as determined experimentally for a linear accelerator Mevatron - MXT. With this, it is intended to provide recommendations for the physical aspects of Quality Assurance (QA) in the radiotherapy treatments, and these will usually be applied by professionals in Medical Physics. In addition to these instructions, it is recommended that additional texts are prepared to address in detail the clinical aspects of the treatments QA

Programação linear no planejamento do tratamento de câncer por radiocirurgia

Medical Physics has been reaching an important role among several lines in Science, providing means for the improvement of several theories and procedures. Currently, its main application is related with the use of ionizing radiations, specially, in treatment procedures such as Radiotherapy. Radiosurgery is a Radiotherapy technique which consists in administering a single tumoricidal dose of radiation exclusively to the tumorous lesion. It becomes then an interesting alternative to surgical treatment, mainly in cerebral metastases, which are the most frequent cerebral tumors in the central nervous system. The radio neurosurgical team works out a planning for the Radiosurgery treatment, aiming for obtaining an appropriate ideal treatment for each case. For the working out of this treatment planning, Computed Tomography images of the region to be treated are obtained, digitalized and later, fused with nuclear magnetic resonance images. Through these images, critical structures, organs at risk and lesions are localized. After this, calculations are made to determine three-dimensional positions of isocenters, isodose curves, prescribed dose, collimators sizes, position, numbers and respective weight of isocentric conformal fields, and others. The treatment planning is commonly based in desired levels of dose for specific types of tumors and organs at risk concerning the irradiated region. Theses levels of dose are chosen in a way that a high probability of cure may be achieved and meanwhile, that the probability of complications, in whichever organ at risk, may be minimal. Thus, many researches have been carried out, showing that mathematical techniques may help to obtain an optimal planning for the treatment of cerebral metastases. Among the methods of optimization in the study...(Complete abstract click electronic access below)

Planejamento de reativos em sistemas elétricos de potência multi-área através de modelos estocásticos

Pós-graduação em Engenharia Elétrica - FEIS

Análise de Tópicos Relevantes em Programação Linear e Aplicações no Ensino de Engenharia

Pós-graduação em Engenharia Elétrica - FEIS

Optimization of in situ derivatization SPME by experimental design for GC-MS multi-residue analysis of pharmaceutical drugs in wastewater

This paper presents the development of a procedure, which enables the analysis of nine pharmaceutical drugs in wastewater using gas chromatography-mass spectrometry (GC-MS) associated with solid-phase microextraction (SPME) for the sample preparation. Experimental design was applied to optimize the in situ derivatization and the SPME extraction conditions. Ethyl chloroformate (ECF) was employed as derivatizing agent and polydimethylsiloxane-divinylbenzene (PDMS-DVB) as the SPME fiber coating. A fractional factorial design was used to evaluate the main factors for the in situ derivatization and SPME extraction. Thereafter, a Doehlert matrix design was applied to find out the best experimental conditions. The method presented a linear range from 0.5 to 10 mu g/L, and the intraday and interday precision were lower than 16%. Applicability of the method was verified from real influent and effluent samples of a wastewater treatment plant, as well as from samples of an industry wastewater and a river.