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Search Results: 1 - 10 of 599942 matches for " A.;De Pieri "
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Experimental study applied to an industrial robot by using variable structure controllers and friction compensation
Garcia, A.;De Pieri, E. R.;Guenther, R.;
Journal of the Brazilian Society of Mechanical Sciences , 2002, DOI: 10.1590/S0100-73862002000400008
Abstract: control of an industrial robot is mainly a problem of dynamics. it includes non-linearities, uncertainties and external perturbations that should be considered in the design of control laws. in this work, two control strategies based on variable structure controllers (vsc) and a pd control algorithm are compared in relation to the tracking errors considering friction. the controller's performances are evaluated by adding an static friction model. simulations and experimental results show it is possible to diminish tracking errors by using a model based friction compensation scheme. a scara robot is used to illustrate the conclusions of this paper.
Experimental study applied to an industrial robot by using variable structure controllers and friction compensation
Garcia A.,De Pieri E. R.,Guenther R.
Journal of the Brazilian Society of Mechanical Sciences , 2002,
Abstract: Control of an industrial robot is mainly a problem of dynamics. It includes non-linearities, uncertainties and external perturbations that should be considered in the design of control laws. In this work, two control strategies based on variable structure controllers (VSC) and a PD control algorithm are compared in relation to the tracking errors considering friction. The controller's performances are evaluated by adding an static friction model. Simulations and experimental results show it is possible to diminish tracking errors by using a model based friction compensation scheme. A SCARA robot is used to illustrate the conclusions of this paper.
Ground-state fidelity in the BCS-BEC crossover
A. Khan,P. Pieri
Physics , 2009, DOI: 10.1103/PhysRevA.80.012303
Abstract: The ground-state fidelity has been introduced recently as a tool to investigate quantum phase transitions. Here, we apply this concept in the context of a crossover problem. Specifically, we calculate the fidelity susceptibility for the BCS ground-state wave function, when the intensity of the fermionic attraction is varied from weak to strong in an interacting Fermi system, through the BCS-BEC crossover. Results are presented for contact and finite-range attractive potentials and for both continuum and lattice models. We conclude that the fidelity susceptibility can be useful also in the context of crossover problems.
Confidence level estimation and analysis optimization
A. Favara,M. Pieri
Physics , 1997,
Abstract: This note proposes a method, which can be applied to searches and more in general to any cross section measurement, to maximize the analysis sensitivity.
Controle farmacognóstico das raízes de Heteropteris aphrodisiaca O. Mach. (Malpighiaceae)
Marques, Luís C.;Pieri, Celina de;Roman-Júnior, Walter A.;Cardoso, Mara L. C.;Milaneze-Gutierre, Maria A.;Mello, Jo?o C. P.;
Revista Brasileira de Farmacognosia , 2007, DOI: 10.1590/S0102-695X2007000400021
Abstract: the roots of heteropteris aphrodisiaca, called " nó-de-cachorro" (dog-knot) for their morphological similarity to the canine penis, are used in popular medicine as an aphrodisiac or stimulant, and to treat dysentery. the objective of the present study was to characterize these roots morphoanatomically and physico-chemically. for the analyses, histological slides were prepared, and aqueous, hydro-ethanol, and ketone extracts were analyzed, from root samples collected in the state of mato grosso, in different seasons of the year. the roots are tuberous, cylindrical, and covered with a striated suber. the cortex, composed of parenchymatous tissue, has no sclerified elements, but shows abundant druses and prismatic crystals of calcium oxalate, as well as idioblasts containing polyphenols. in the secondary xylem, gelatinous fibers are abundant, typical for the roots of species of the brazilian cerrado (savanna). the physical and chemical analyses revealed greater losses through desiccation in the samples collected in spring and summer. water was the best extraction liquid. total ash content of the samples ranged from 3.4% in summer to 5.3% in autumn. total phenol content was higher in spring (10.2%), suggesting this season as the most appropriate to harvest the plant drug. chromatographic analyses through tlc and hplc were employed using the flavonoids neoastilbin, astilbin, and isoastilbin as markers. the rf values were 0.60, 0.68 and 0.74, and the retention time were 16.44, 16.91 and 18.08 min, respectively.
Evaluating the effects of introduction of computers in Brazilian public schools Avaliando os efeitos da introdu o de computadores em escolas públicas brasileiras
Sergio Pinheiro Firpo,Renan Gomes De Pieri
Revista Brasileira de Inova??o , 2012,
Abstract: This paper analyzes the effects of using computers and other information and communication technologies in schools. For this, we evaluate the first stage of a program that distributed computers and other computer accessories and trained teachers from schools belonging to municipalities with low HDI. We estimate the program’s impact on student performance variables and school resources variables. As a result, we find that despite the significant increase in access to computer and science labs by participant schools, the program’s impact in the short term is negative on performance of students of grades 4th and 8th. However, for students in 4th grade, this negative result is smaller over time, indicating that there seems to be a long term positive effect, although small, between younger children and exposed to new information technologies. This result is not found for the 8th grade, where we find longterm outcomes null or negative, indicating that older children, when exposed to information technology in schools, do not exhibit learning gains. Resumo O presente artigo tem como objetivo analisar os efeitos do uso de computadores e outras tecnologias de informa o e comunica o nas escolas. Para isso, avalia-se a primeira etapa de um programa que distribuiu computadores e outros acessórios de informática e treinou professores de escolas pertencentes a municípios com baixo IDH. Estimou-se o impacto do programa sobre variáveis de desempenho dos alunos e variáveis de recursos nas escolas. Como resultado, observa-se que, a despeito do aumento significativo do acesso aos laboratórios de informática e ciência pelas escolas participantes, o impacto do programa no curto prazo tende a ser negativo sobre o desempenho dos alunos da 4a e 8a séries do ensino fundamental. Contudo, para alunos da 4a série, esse resultado negativo fica menor em termos absolutos ao longo do tempo, indicando que parece haver um efeito de longo prazo positivo, porém pequeno, entre crian as mais novas e expostas às novas tecnologias de informa o. Tal resultado n o é encontrado para a 8a série, onde foram verificados resultados de longo prazo nulos ou negativos, indicando que crian as mais velhas, quando expostas a tecnologias de informa o nas escolas, n o apresentam ganhos de aprendizado.
R&D ADMINISTRATION IN THE HIGH TECHNOLOGY INDUSTRY: HOW TO MANAGE A PARADOX ADMINISTRA O DE P&D NA INDúSTRIA DE ALTA TECNOLOGIA: COMO GERENCIAR UM PARADOXO?
Nobuiuki Costa Ito,Mihail de Pieri Mirica
Future Studies Research Journal : Trends and Strategies , 2011, DOI: 10.7444/future.v2i2.60
Abstract: The competitive environment of the knowledge age is getting more complex, dynamic, and fast-moving each day. The high tech industry is intensively tied to its effects and demands for innovation, so the field of Research and Development must act strategically, generating innovations and granting success and sustainability to the business. However, there is a paradox in R&D which may lay traps and obstacles disguised by the busy day-to-day activity of the organization. The purpose of this paper is to point out directions that managers may take to cope with these contradictions in R&D administration. The R&D paradox is rooted in the conflict between exploitation, achieved by continual improvement through incremental innovation, and by exploration, which seeks new opportunities in the creation of new technologies through disruptive innovations. These two sides of the paradox demand different, and sometimes even divergent, organizations. Top management leadership is crucial for the acceptance and balancing of the contradictions created by this paradox, and can align exploitation/exploration through distributive and integrative decisions and transform companies into truly ambidextrous organizations. Key-words: Research & Development. Innovation. Paradox. Ambidextrous organizations. Strategy. O ambiente competitivo da Era do Conhecimento é cada vez mais complexo, dinamico e veloz. A indústria de alta tecnologia vive intensamente esses efeitos e as exigências por inova es. Assim, a área de P&D atua estrategicamente, gerando inova es e garantindo o sucesso e a sustentabilidade do negócio. Entretanto, existe um paradoxo na área de P&D que pode criar armadilhas e obstáculos mascarados pela correria das atividades diárias. Este é um estudo é realizado por meio de uma revis o bibliográfica e argumenta o teórica. O objetivo deste trabalho é indicar caminhos para os gerentes conduzirem as atividades de P&D sob uma perspectiva do paradoxo exploit / explore. O paradoxo da P&D é causado pelo conflito entre eficiência, obtida por melhorias contínuas por intermédio de inova es incrementais, e pela explora o, que busca novas oportunidades na cria o de novas tecnologias pelas inova es de ruptura. Essas duas faces do paradoxo exigem organiza es diferentes e, frequentemente, divergentes. A lideran a da alta administr
Paradiplomacia y descentralización política: breve análisis sobre las contribuciones del Comité de las Regiones en la Unión Europea
Vítor Stuart Gabriel de Pieri
Meridiano 47 : Boletim de Análise de Conjuntura em Rela??es Internacionais , 2010,
Abstract: Em época de crise financeira na zona do Euro, causada principalmente pela falta de políticas fiscais articuladas e condizentes com as políticas monetárias regionais - observadas especialmente nos PIIGS (Portugal, Irlanda, Itália, Grécia e Espanha) - é interessante refletir sobre pontos positivos do processo de integra o européia. Um dos maiores méritos do avan o da integra o foi a descentraliza o das decis es políticas relacionadas ao Desenvolvimento Regional, responsável pela melhoria das condi es sócio-espaciais de países como Espanha, Portugal e Grécia.
Reduced-Order Modelling of the Bending of an Array of Torsional Micromirrors
A. Molfese,A. Nannini,F. Pieri
Computer Science , 2007,
Abstract: Reduced-Order Modelling of the Bending of an Array of An array of micromirrors for beam steering optical switching has been designed in a thick polysilicon technology. A novel semi-analytical method to calculate the static characteristics of the micromirrors by taking into account the flexural deformation of the structure is presented. The results are compared with 3D coupled-field FEM simulation.
Lamella formation and emigration from the water by a laboratory colony of Biomphalaria glabrata (SAY) in flow-through system
Dannemann, Ricardo D. A.;Pieri, Otavio S.;
Memórias do Instituto Oswaldo Cruz , 1992, DOI: 10.1590/S0074-02761992000500016
Abstract: lamella formation and emigration from the water were investigated in juvenile biomphalaria glabrata reared at two temperatures in aquaria with a constant water flow. most snails (97.4%) reared at the lower temperature (21- c) formed lamella at the shell aperture and emigrated from the water, whereas only 10.1% did so at 25- c. eighty percent of emigrations at 21- c occurred within a period of 15 days, 70-85 days after hatching. a comparison of the studies done so far indicates that the phenomenon may be affected by the ageing of snail colonies kept in the laboratory and their geographic origin, rather than the rearing conditions. this hypothesis, however, requires experimental confirmation.
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