902 resultados para Permutation Ordered Binary Number System


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This study evaluates the influence of different cartographic representations of in-car navigation systems on visual demand, subjective preference, and navigational error. It takes into account the type and complexity of the representation, maneuvering complexity, road layout, and driver gender. A group of 28 drivers (14 male and 14 female) participated in this experiment which was performed in a low-cost driving simulator. The tests were performed on a limited number of instances for each type of representation, and their purpose was to carry out a preliminary assessment and provide future avenues for further studies. Data collected for the visual demand study were analyzed using non-parametric statistical analyses. Results confirmed previous research that showed that different levels of design complexity significantly influence visual demand. Non-grid-like road networks, for example, influence significantly visual demand and navigational error. An analysis of simple maneuvers on a grid-like road network showed that static and blinking arrows did not present significant differences. From the set of representations analyzed to assess visual demand, both arrows were equally efficient. From a gender perspective, women seem to took at the display more than men, but this factor was not significant. With respect to subjective preferences, drivers prefer representations with mimetic landmarks when they perform straight-ahead tasks. For maneuvering tasks, landmarks in a perspective model created higher visual demands.

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This paper deals with a stochastic stability concept for discrete-time Markovian jump linear systems. The random jump parameter is associated to changes between the system operation modes due to failures or repairs, which can be well described by an underlying finite-state Markov chain. In the model studied, a fixed number of failures or repairs is allowed, after which, the system is brought to a halt for maintenance or for replacement. The usual concepts of stochastic stability are related to pure infinite horizon problems, and are not appropriate in this scenario. A new stability concept is introduced, named stochastic tau-stability that is tailored to the present setting. Necessary and sufficient conditions to ensure the stochastic tau-stability are provided, and the almost sure stability concept associated with this class of processes is also addressed. The paper also develops equivalences among second order concepts that parallels the results for infinite horizon problems. (C) 2003 Elsevier B.V. All rights reserved.

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PURPOSE. To compare intraoperative injection of triamcinolone and ciprofloxacin in a controlled-release system (DuoCat) with prednisolone and ciprofloxacin eye drops after cataract surgery.METHODS. In this randomized, double-masked, controlled trial, a total of 135 patients undergoing cataract surgery were randomly allocated to two groups: 67 patients treated after surgery with prednisolone 1% and ciprofloxacin 3% eye drops four times daily (week 1), three times daily (week 2), twice daily (week 3), and once daily (week 4) and 0.3% ciprofloxacin drops four times daily (weeks 1 and 2), and 68 patients treated at the end of surgery with a sub-Tenon's injection of 25 mg triamcinolone and 2 mg ciprofloxacin in biodegradable microspheres. The patients were examined on postoperative days 1, 3, 7, 14, and 28. The main outcome measures were postoperative anterior chamber cell and flare, intraocular pressure (IOP), lack of anti-inflammatory response, and presence of infection.RESULTS. No significant differences were observed between the groups in anterior chamber cell (P > 0.14) and flare (P > 0.02) at any postoperative visits. The mean (99% confidence interval) differences in IOP between the prednisolone and triamcinolone groups on days 1, 3, 7, 14, and 28 were -0.4 mm Hg (-2.1 to 1.3), 0.0 mm Hg (-1.4 to 1.3), 0.0 mm Hg (-1.1 to 1.1), -0.2 mm Hg (-1.1 to 0.8), and -0.1 mm Hg (-1.1 to 0.9), respectively. No patient had a postoperative infection.CONCLUSIONS. One injection of DuoCat had a therapeutic response and ocular tolerance that were equivalent to conventional eye drops in controlling inflammation after cataract surgery. (Clinical-Trials. gov number, NCT00431028.) (Invest Ophthalmol Vis Sci. 2009; 50: 3041-3047) DOI: 10.1167/iovs.08-2920

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

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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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Economic dispatch (ED) problems have recently been solved by artificial neural network approaches. Systems based on artificial neural networks have high computational rates due to the use of a massive number of simple processing elements and the high degree of connectivity between these elements. The ability of neural networks to realize some complex non-linear function makes them attractive for system optimization. All ED models solved by neural approaches described in the literature fail to represent the transmission system. Therefore, such procedures may calculate dispatch policies, which do not take into account important active power constraints. Another drawback pointed out in the literature is that some of the neural approaches fail to converge efficiently toward feasible equilibrium points. A modified Hopfield approach designed to solve ED problems with transmission system representation is presented in this paper. The transmission system is represented through linear load flow equations and constraints on active power flows. The internal parameters of such modified Hopfield networks are computed using the valid-subspace technique. These parameters guarantee the network convergence to feasible equilibrium points, which represent the solution for the ED problem. Simulation results and a sensitivity analysis involving IEEE 14-bus test system are presented to illustrate efficiency of the proposed approach. (C) 2004 Elsevier Ltd. All rights reserved.

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

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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This paper presents a proposal for a Quality Management System for a generic GNSS Surveying Company as an alternative for management and service quality improvements. As a result of the increased demand for GNSS measurements, a large number of new or restructured companies were established to operate in that market. Considering that GNSS surveying is a new process, some changes must be performed in order to accommodate the old surveying techniques and the old fashioned management to the new reality. This requires a new management model that must be based on a well-described procedure sequence aiming at the Total Management Quality for the company. The proposed Quality Management System was based on the requirements of the Quality System ISO 9000:2000, applied to the whole company, focusing on the productive process of GNSS surveying work.

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A constructive heuristic algorithm (CHA) to solve distribution system planning (DSP) problem is presented. The DSP is a very complex mixed binary nonlinear programming problem. A CHA is aimed at obtaining an excellent quality solution for the DSP problem. However, a local improvement phase and a branching technique were implemented in the CHA to improve its solution. In each step of the CHA, a sensitivity index is used to add a circuit or a substation to the distribution system. This sensitivity index is obtained by solving the DSP problem considering the numbers of circuits and substations to be added as continuous variables (relaxed problem). The relaxed problem is a large and complex nonlinear programming and was solved through an efficient nonlinear optimization solver. Results of two tests systems and one real distribution system are presented in this paper in order to show the ability of the proposed algorithm.

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A method for the attachment of 2-mercaptothiazoline (MTZ) to modified silica gel has been developed. In the first step, a new silylant agent was synthesized, named SiMTZ, by the reaction between MTZ molecule and chloropropyltrimethoxysilane (SiCl). SiMTZ and tetraethylortosilicate were co-condensed in the presence of n-dodecylamine, a neutral surfactant template, to produce a modified ordered hexagonal mesoporous silica named HMTZ. The modified material contained 0.89 +/- 0.03 mmol of 2-mercaptothiazoline per gram of silica. FT-IR, FT-Raman, Si-29- and C-13-NMR spectra were in agreement with the proposed structure of the modified mesoporous silica in the solid state. HMTZ material has been used for divalent mercury adsorption from aqueous solution at 298 I K. The series of adsorption isotherms were adjusted to a modified Langmuir equation. The maximum number of moles of mercury adsorbed gave 2.34 +/- 0.09 mmol/g of material. The same interaction was followed by calorimetric titration on an isoperibol calorimeter. The HMTZ presented a high capacity for the removal of the contaminant mercury from water. The Delta H and Delta G values for the interaction were determined to be -56.34 +/- 1.07 and -2.14 +/- 0.11 kJ mol(-1). This interaction process was accompanied by a decrease of entropy value (- 182 J mol(-1) K-1). Thus, the interaction between mercury and HMTZ resulted in a spontaneous thermodynamic system with a high favorable exothermic enthalpic effect. (c) 2007 Elsevier B.V. All rights reserved.

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Borate glasses present an absorption coefficient very close to that of human tissue. This fact makes some borates ideal materials to develop medical and environmental dosimeters. Glass compositions with calcium tetraborate (CaB4O7) and calcium metaborate (CaB2O4), such as the xCaB(4)O(7) - (100-x)CaB2O4 System (0 <= x <= 100 wt%) were obtained by the traditional melting/quenching method. A phenomenon widely known as the 'boron anomaly' was observed in our thermal analysis measurements, as indicated by the increase of T, and the appearance of a maximum value in the composition with 40 wt% of CaB2O4. The Dy doped and Li co-doped 80CaB(4)O(7)-20CaB(2)O(4) (Wt%) glass samples were studied by the thermoluminescence technique. The addition of Dy improved the signal sensitivity in about three times with respect to the undoped glass sample. The addition of Li as a co-dopant in this glass caused a shift to a lower temperature of about 20 degrees C in the main glow peak. The structural analysis of the 80CaB(4)O(7)-20CaB(2)O(4) (wt%) undoped and doped samples were studied through infrared absorption. We have noted an increase in the coordination number of the boron atoms from 3 to 4, i.e., the conversion of the BO3 triangular structural units into BO4 tetrahedra. (c) 2006 Elsevier B.V. All rights reserved.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)