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Search Results: 1 - 10 of 98133 matches for " Maria Cristina Szpak;Neves-Jr "
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Um método evolucionário para sintonia de controladores PI/PID em processos multivariáveis
Arruda, Lúcia Valéria R. de;Swiech, Maria Cristina Szpak;Neves-Jr, Flávio;Delgado, Myriam Regattieri;
Sba: Controle & Automa??o Sociedade Brasileira de Automatica , 2008, DOI: 10.1590/S0103-17592008000100001
Abstract: nonlinear multiple-input multiple-output (mimo) processes which are common in industrial plants are characterized by significant interactions and nonlinearities among their variables. thus, the tuning of several controllers in complex industrial plants is a challenge for process engineers and operators. this paper addresses the problem of simultaneously tuning n proportional-integral-derivative (pi/pid) controllers in a coupled multivariable process as a multi-criteria optimization problem. a multi objective genetic algorithm modified by a niching technique with castes formation is proposed to solve this problem. the optimization is carried out in two levels. in the first level a local function that considers both the integral time squared error (itse) and the minimum variance criteria is computed to separately evaluate the performance of each closed loop. thereafter, a global cost function that considers all the loops is used to compute a set of solutions (a set of pi/pid parameters) to the optimization problem. the proposed system was applied to the control of a fluid catalytic cracking (fcc) unit, and its performance was compared to dynamic matrix control (dmc). the results show the applicability and effectiveness of the proposed method.
Um modelo híbrido (CLP-MILP) para scheduling de opera??es em polidutos
Magat?o, Leandro;Arruda, Lúcia Valéria Ramos de;Neves-Jr, Flávio;
Pesquisa Operacional , 2008, DOI: 10.1590/S0101-74382008000300007
Abstract: this work is motivated by the need of optimization in the pipeline-oil distribution scenario. the considered problem involves the short-term scheduling of activities in a specific pipeline. the pipeline is 93.5 km in length, and it connects refinery and harbor tankfarms, conveying different types of commodities (gasoline, diesel, kerosene, etc). an optimization model was developed to determine the pipeline scheduling with improved efficiency. such model combines constraint logic programming (clp) and mixed integer linear programming (milp) in an integrated clp-milp framework. the proposed model uses decomposition strategies, continuous time representation, and intervals that represent time constraints (time windows). real cases were solved in a reduced computational time (order of seconds). the computational results have demonstrated that the model is able to define new operational points to the pipeline, providing significant cost saving. indeed the clp-milp model is an efficient tool to aid the operational decision-making within this real-world pipeline scenario.
Redes dinamicas cognitivas aplicadas no controle supervisório de um fermentador
Mendon?a, Márcio;Arruda, L. V. R.;Neves-Jr, Flávio;
Sba: Controle & Automa??o Sociedade Brasileira de Automatica , 2011, DOI: 10.1590/S0103-17592011000400003
Abstract: this paper uses dynamic cognitive networks (dcn) as an intelligent tool for supervisory control. the dcns are an evolution of fuzzy cognitive maps (fcm). intelligent systems and tools use expert knowledge to build models with inference and / or decision taking abilities. a supervisory control architecture for an alcoholic fermentation process is developed from the acquisition of empirical knowledge from an expert. the objective of the supervisor is to operate the process in normal and critical situations. for this, we propose the use of a dcn model with new types of concepts and relationships that not only represent cause-effect as in fcm models. simulation results are presented to validate the architecture developed.
Identifica??o genética de modelos por pólos e zeros baseada no compromisso entre os erros de polariza??o e variancia
Arruda, L.V.R.;Fávaro, Sílvio;Neves-Jr., F.;
Sba: Controle & Automa??o Sociedade Brasileira de Automatica , 2003, DOI: 10.1590/S0103-17592003000200001
Abstract: this work proposes a genetic algorithm (ga) to solve process estimation problems when the real process presents high orders polynomials (complexity model) or non-linearities, non-minimum phase behavior, etc. the algorithm finds the best linear model in the pole and zero form to represent the real plant using its input and output signals. a new chromosome representation was introduced and a new ''fitness'' function based on the tradeoff bias x variance was developed. to validate this genetic estimator, simulations studies were done and the ga performance was compared with one obtained by use of the traditional least square estimation method.
Identifica o genética de modelos por pólos e zeros baseada no compromisso entre os erros de polariza o e variancia
Arruda L.V.R.,Fávaro Sílvio,Neves-Jr. F.
Sba: Controle & Automa??o Sociedade Brasileira de Automatica , 2003,
Abstract: Este trabalho prop em um algoritmo genético aplicado ao problema de identifica o de plantas n o-lineares, de fase n o-mínima ou plantas lineares de ordem superior. O algoritmo proposto tem como objetivo encontrar um modelo linear na forma de pólos e zeros e de ordem reduzida, que melhor represente a planta real, a partir dos sinais de entrada e saída. Uma proposta inovadora para a representa o dos indivíduos e fun o de ''fitness'' foi desenvolvida neste trabalho. Esta fun o de fitness representa o compromisso entre os erros de polariza o e variancia do modelo estimado. Já a representa o proposta divide o espa o de busca em dois subespa os: um destinado à busca de pólos e zeros de natureza real e outro com a finalidade de se encontrar os pólos e zeros complexos. Resultados de simula o s o utilizados para ilustrar o desempenho do estimador genético desenvolvido.
Ensino da lideran?a em enfermagem: um estudo bibliométrico
Neves, Vanessa Ribeiro;Sanna, Maria Cristina;
Acta Paulista de Enfermagem , 2012, DOI: 10.1590/S0103-21002012000200024
Abstract: objectives: to quantify and describe the characteristics of scientific production on the teaching of nursing leadership concerning the type of publication, year, vehicle, country, language and theme. methods: a descriptive and bibliometric study conducted in databases of the bvs, using descriptors: teaching, leadership and nursing. results: over 37 years, we identified 73 publications, mostly found in the medline database and consisting of original articles published in north american journals, written in english, and dealing with teaching strategies. conclusions: the scientific production was sparse but constant during the study period, authored predominantly by north americans, and published in scientific journals in the united states, which indicated the necessity to develop research on the subject in brazil.
Mixoma Cardíaco: Patologia e Correla??o Clínica em Material de Ressec??o Cirúrgica
Ferreira,Maria Cristina Furian; Pott Jr.,Henrique;
Arquivos de Medicina , 2009,
Abstract: introduction: the cardiac myxoma (cm) is a primary tumor of the heart, often of unknown etiology prevalent in adults in the third and sixth decades of life. it is characterized by abnormal cell proliferation of multipotencial mesenchymal subendocardial cells jeopardizing the route of entry of one or both ventricles. although its pathogenesis is poorly understood, it is known that their clinical manifestations may be varied according to topography and cardiac involvement. in this study, we intend to describe the morphologic aspects of cm and associate them to the patient’s clinical data, and to discuss the pathogenesis of mc. methods: this retrospective study, type case series used samples of surgical resection ?xed in formalin 10% from patients with echocardiographic diagnosis of mc, operated from 2007 to 2008. results: we describe the anatomo-clinical characteristics of six cardiac myxomas of the left atrium in patients aged between 19 and 69 years. macroscopically it were identi?ed two anatomic types. the clinical presentation produced by the cardiac tumor included non-speci?c events and manifestations related to left ventricular ?lling obstruction or embolization to the brain vessels. it was also established that the clinical presentation correlates with the tumor aspect. conclusions: although the mc are histologically benign, they can be lethal due to its strategic position. its increasing incidence and morbidity is necessary to include this nosological entity in the differential diagnosis of diseases that presents as cerebral thromboembolism and heart failure syndromes. the symptoms presented by patients correlates with the appearance, size, mobility and location of the tumor.
Influência da antibiose exercida por actinomicetos às estirpes de Bradyrhizobium SPP., na nodula??o da soja
Pereira, Jo?o Carlos;Neves, Maria Cristina Prata;Drozdowicz, Adam;
Pesquisa Agropecuária Brasileira , 1999, DOI: 10.1590/S0100-204X1999000100014
Abstract: the aim of this work was to evaluate the antibiotic spectrum of actinomycetes from cerrado soils and their influence on soybean nodulation. strains br 29, br 33, br 40, br 85, br 86, br 96, 47/587, 3b-7 and 4a-5 of bradyrhizobium spp. were characterized by their natural resistence to antibiotics produced by 204 actinomycete isolates. the strains br 29 and br 96 of b. elkanii were sensitive to 5.2% and 9.9% the products of actinomycete isolates, respectively, while br 33 was sensitive up to 20.3%. the antagonistic effects caused by actinomycete exclusively to br 29 and br 33 were 1.6% and 5.7% respectively. this effect was not observed for strains br 40 and br 96. single and multistrains inoculations in the presence or absence of actinomycetes affected soybean nodulation. on double strain inoculations, with br 33 and br 29 mixed with actinomycete 370 there was a decrease in nodule occupancy by br 29 from 94.1% to 83.7% with concomitant increase in the occupying of br 33 from 6.7% to 17.2%. the results indicate the importance of ecological studies on actinomycetes population in order to access their role in the establishment of efficient nodulation.
Dinamica das popula??es bacterianas em solos de Cerrados
Pereira, Jo?o Carlos;Neves, Maria Cristina Prata;Drozdowicz, Adam;
Pesquisa Agropecuária Brasileira , 1999, DOI: 10.1590/S0100-204X1999000500011
Abstract: among tropical environments, cerrados stand out because of its agriculture potencial. although microorganisms play an important role on soil sustainability and crop production, few information is available on the effects of soil management systems on cerrado's microbial ecology. in this study the effects of environmental conditions and soil management practices on bacterial populations were evaluated. bacterial population densities in soil under native vegetation were variable and diferentiated. actinomycetes densities varied from 1.7 to 50 x 104 cfu/g dry soil in sete lagoas region, brazil, whereas bacterial populations in both the first and second year of land use were similar and higher than those from soil under native vegetation in the planaltina region. soil management practices did not cause strong modifications in the equilibrium among actinomycetes populations obtained from both spores and hyphal. the spore/hypha ratios varied from 1.1 to 5.8. correlation coefficients among actinomycetes and other bacteria populations were signifficant in soybeans rhizospheres. results show that soil management practices used for soybean cultivation in cerrado soils may influence the equilibrium of bacterial populations.
Características de idosos acometidos pela doen a de Alzheimer e seus familiares cuidadores principais
Paula Cristina Barros de Matos,Maria das Neves Decesaro
Revista Eletr?nica de Enfermagem , 2012,
Abstract: O objetivo deste trabalho foi caracterizar idosos acometidos pela doen a de Alzheimer e seus familiares cuidadores principais. Trata-se de estudo descritivo, realizado no município de Maringá-PR, no período de dezembro de 2010 a mar o de 2011, desenvolvido com oitenta cuidadores. Os dados foram coletados por meio de entrevista e analisados porprocedimentos estatísticos com análise por frequência simples e percentual absoluto. A maioria dos cuidadores era do sexo feminino, com idade média de 54,8 anos, casada, com 8 anos ou mais de estudo, e possuía algum problema de saúde. Dos idosos, a maioria era do sexo feminino, com idade média de 80,8 anos, tinha 3 anos ou menos de estudo, possuía comorbidades e estava no estágio moderado da doen a. Conhecer o perfil dos cuidadores e doentes pode contribuir para ado o de estratégias de interven o por parte dos profissionais de saúde que atendam as necessidades de forma individualizada e humanizada.
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