901 resultados para Two term control systems
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Linear single-stage vibration isolation systems have a limitation on their performance, which can be overcome passively by using linear two-stage isolations systems. It has been demonstrated by several researchers that linear single-stage isolation systems can be improved upon by using nonlinear stiffness elements, especially for low-frequency vibrations. In this paper, an investigation is conducted into whether the same improvements can be made to a linear two-stage isolation system using the same methodology for both force and base excitation. The benefits of incorporating geometric stiffness nonlinearity in both upper and lower stages are studied. It is found that there are beneficial effects of using nonlinearity in the stiffness in both stages for both types of excitation. Further, it is found that this nonlinearity causes the transmissibility at the lower resonance frequency to bend to the right, but the transmissibility at the higher resonance frequency is not affected in the same way. Generally, it is found that a nonlinear two-stage system has superior isolation performance compared to that of a linear two-stage isolator.
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Pós-graduação em Ciência e Tecnologia Animal - FEIS
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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In this work a Nonzero-Sum NASH game related to the H2 and H∞ control problems is formulated in the context of convex optimization theory. The variables of the game are limiting bounds for the H2 and H∞ norms, and the final controller is obtained as an equilibrium solution, which minimizes the `sensitivity of each norm' with respect to the other. The state feedback problem is considered and illustrated by numerical examples.
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Solid-organ transplant recipients present a high rate of non-adherence to drug treatment. Few interventional studies have included approaches aimed at increasing adherence. The objective of this study was to evaluate the impact of an educational and behavioral strategy on treatment adherence of kidney transplant recipients. In a randomized prospective study, incident renal transplant patients (n = 111) were divided into two groups: control group (received usual transplant patient education) and treatment group (usual transplant patient education plus ten additional weekly 30-min education/counseling sessions about immunosuppressive drugs and behavioral changes). Treatment adherence was assessed using ITAS adherence questionnaire after 3 months. Renal function at 3, 6, and 12 months, and the incidence of transplant rejection were evaluated. The non-adherence rates were 46.4 and 14.5 % in the control and treatment groups (p = 0.001), respectively. The relative risk for non-adherence was 2.59 times (CI 1.38-4.88) higher in the control group. Multivariate analysis demonstrated a 5.84 times (CI 1.8-18.8, p = 0.003) higher risk of non-adherence in the control group. There were no differences in renal function and rejection rates between groups. A behavioral and educational strategy addressing the patient's perceptions and knowledge about the anti-rejection drugs significantly improved the short-term adherence to immunosuppressive therapy.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Composting is considered a process that enables adding value to organic solid waste turning them into organic fertilizer. In this process, factors such as mishandling the windrow, failed to control the temperature, aeration and moisture content will result in the quality of waste decomposition, and thus affect the quality of the final compound. Decentralized systems such as home composting, composting in restaurants, food courts and schools are one of the solutions for valuing these waste in a non expensive way and with greater quality. For this purpose, the project aims to analyze the conditions for composting of solid waste of the University Restaurant of Rio Claro- SP, through two different composting systems: manual revolving windrow and static pile. It was found that in University Restaurant (RU) on average 33% by weight of the total waste generated in the property are capable of composting. In this sense, in order to investigate the preliminary process operation parameters were mounted one manual windrow composed of 100% of the UR waste and a static pile composed of 60% of the UR waste and 40% of pruning and grass residues (PG). This study analyzed the manual revolving windrow and static pile systems for the parameters: moisture content, pH, C / N ratio and temperature. The study of the proportions of the PG and UR waste pointed to the need for pruning and grass residues addition for composting, considering that the manual revolving windrow composed by 100% of the UR waste had no satisfactory performance due to low temperatures measured during 60 days analysis. The best ratio for manual revolving windrow method analyzed in this study was 60% of the UR waste and 40% of PG waste, in dry weight. From this proportion a static pile was assembled, composed of 60% of UR waste e 40% of PG waste from the maintenance activities of the green area of the university. The biological activity in the static pile reached the maximum temperature of ...
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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In this paper, we propose an extension of the invariance principle for nonlinear switched systems under dwell-time switched solutions. This extension allows the derivative of an auxiliary function V, also called a Lyapunov-like function, along the solutions of the switched system to be positive on some sets. The results of this paper are useful to estimate attractors of nonlinear switched systems and corresponding basins of attraction. Uniform estimates of attractors and basin of attractions with respect to time-invariant uncertain parameters are also obtained. Results for a common Lyapunov-like function and multiple Lyapunov-like functions are given. Illustrative examples show the potential of the theoretical results in providing information on the asymptotic behavior of nonlinear dynamical switched systems. (C) 2012 Elsevier B.V. All rights reserved.
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The human eye is sensitive to visible light. Increasing illumination on the eye causes the pupil of the eye to contract, while decreasing illumination causes the pupil to dilate. Visible light causes specular reflections inside the iris ring. On the other hand, the human retina is less sensitive to near infra-red (NIR) radiation in the wavelength range from 800 nm to 1400 nm, but iris detail can still be imaged with NIR illumination. In order to measure the dynamic movement of the human pupil and iris while keeping the light-induced reflexes from affecting the quality of the digitalized image, this paper describes a device based on the consensual reflex. This biological phenomenon contracts and dilates the two pupils synchronously when illuminating one of the eyes by visible light. In this paper, we propose to capture images of the pupil of one eye using NIR illumination while illuminating the other eye using a visible-light pulse. This new approach extracts iris features called "dynamic features (DFs)." This innovative methodology proposes the extraction of information about the way the human eye reacts to light, and to use such information for biometric recognition purposes. The results demonstrate that these features are discriminating features, and, even using the Euclidean distance measure, an average accuracy of recognition of 99.1% was obtained. The proposed methodology has the potential to be "fraud-proof," because these DFs can only be extracted from living irises.