851 resultados para Path feasibility
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Incluye Bibliografía
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A low-cost electrochemical method was developed for the determination of trace-level of methyl parathion (MP) based on the properties of graphite-modified basal plane pyrolytic graphite electrode (graphite-bppg). A combination of graphite-bppg with square-wave voltammetric (SWV) analysis resulted in an original, sensitive and selective electrochemical method for determination of MP pesticide in drinking water. The electrode was constructed and the electrochemical behavior of MP was studied. Immobilization is achieved via film modification from dispersing graphite powder in deionized water and through pipeting a small volume onto the electrode surface allowing the solvent to volatilize. The strong affinity of the graphite modifier for the phosphorous group of the MP allowed the deposition of a significant amount of MP in less than 60 seconds. The cyclic voltammetric results indicate that the graphite-bppg electrode can enhance sensitivity in current intensity towards the quasi-reversible redox peaks of the products of the cathodic reduction of the nitro group at negative potential (peak I = 0.077 V and peak II = –0.062 V) and that the cathodic irreversible peak (peak III = –0.586 V) in comparison with bare bppg electrode and is also adsorption controlled process. Under optimized conditions, the concentration range and detection limit for MP pesticide are respectively 79.0 to 263.3 mmol L-1 and 3.00 mmol L-1. The proposed method was successfully applied to MP determination in drinking water and the performance of this electrochemical sensor has been evaluated in terms of analytical figures of merit.
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The Economic Commission for Latin America and the Caribbean (ECLAC), Subregional Headquarters for the Caribbean, and secretariat of the Caribbean Development and Cooperation Committee (CDCC) convened a Seminar on Caribbean Development Thinking: The Path Covered and the Way Forward, in Port of Spain on 21 October 2009. The meeting was attended by representatives of the following CDCC member countries: Dominica, Grenada, Guyana, Jamaica, Saint Lucia, Saint Kitts and Nevis, Saint Vincent and the Grenadines, Suriname and Trinidad and Tobago. Representatives of the following organizations of the United Nations system also attended: the International Labour Organisation (ILO); Joint United Nations Project on HIV/AIDS (UNAIDS); and the United Nations Development Programme (UNDP). The following intergovernmental organizations were represented: the Caribbean Community (CARICOM); the Caribbean Development Bank (CDB); the Caribbean Regional Negotiating Mechanism/Caribbean Community (CRNM/CARICOM); Delegation of the European Commission in Trinidad and Tobago; the Organisation of American States (OAS); and the Organisation of Eastern Caribbean States (OECS). The University of the West Indies (UWI) also participated. The list of participants appears as annex I to this report.
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As capoeiras - áreas alteradas por ação antrópica que se encontram em estágios de regeneração espontânea de cobertura florestal - são componentes da paisagem rural de grande significado na Amazônia. No último Censo Agropecuário, as áreas de capoeira perfaziam 4,5 milhões de hectares em toda a Região Norte. Uma literatura crescentemente importante considera tais áreas proxy de economias rurais decadentes e insustentáveis, sobre as quais se ergue uma pecuária de corte eficiente e sustentável. Este artigo procura estabelecer os diferentes tipos de capoeira que se constatam na economia rural da Amazônia, associando-as às diferentes formas de produção, cujos sistemas se expressam dinamicamente como trajetórias tecnológicas concorrentes. A partir daí a) demonstra que parte dessas áreas resulta de mudanças positivas nos sistemas produtivos que produzem capoeiras com grande capacidade de regeneração – estando associada, portanto, a inovações relevantes para o desenvolvimento da Região numa perspectiva que incorpora critérios de sustentabilidade ambiental; b) demonstra que os tipos de capoeira que indicam degradação, pela baixa capacidade de regeneração, se associam à pecuária de corte, a qual na Região tem apresentado dificuldades estruturais de modernização técnica e c) indica que o ambiente institucional, favorecendo os sistemas que produzem capoeira degradada em detrimento daqueles que produzem capoeiras de rápida recomposição, podem aprisionar (levar a um lock-in) a economia agrária da região nas piores soluções, tanto econômica, quanto social e ecologicamente.
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In this paper, we propose a hybrid methodology based on Graph-Coloring and Genetic Algorithm (GA) to solve the Wavelength Assignment (WA) problem in optical networks, impaired by physical layer effects. Our proposal was developed for a static scenario where the physical topology and traffic matrix are known a priori. First, we used fixed shortest-path routing to attend demand requests over the physical topology and the graph-coloring algorithm to minimize the number of necessary wavelengths. Then, we applied the genetic algorithm to solve WA. The GA finds the wavelength activation order on the wavelengths grid with the aim of reducing the Cross-Phase Modulation (XPM) effect; the variance due to the XPM was used as a function of fitness to evaluate the feasibility of the selected WA solution. Its performance is compared with the First-Fit algorithm in two different scenarios, and has shown a reduction in blocking probability up to 37.14% when considered both XPM and residual dispersion effects and up to 71.42% when only considered XPM effect. Moreover, it was possible to reduce by 57.14% the number of wavelengths.
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Several cognitive tests have been developed to evaluate specific aspects of human and animal learning and memory. These tests have been used for early detection of cognitive deficits and to monitor the treatment of dogs with cognitive impairment. Thus, this article evaluated the feasibility of cognitive tests for use in canine neurology clinical routines and the suitability of the different tests to accomplish this aim. Fifteen healthy adult dogs were used for the cognitive tests of reward approach learning, object approach learning, object discrimination learning, reversal learning, delayed non-matched to position, and delayed non-matched to sample to assess different aspects of memory. No difference was observed between tests of delayed non-matched to position (3.13 +/- 2.23 days) and delayed non-matched to sample (3.20 +/- 2.40 days) (P = 0.944). However, dogs had greater difficulty in reversal learning (8.47 +/- 2.61 days) than in object discrimination learning (4.60 +/- 1.64 days) (P <= 0.001). Based on the tests performed, the delayed non-matched to position test may be performed in clinical routine if the owner and the veterinarian have time available, because this test is sensitive to evaluate dogs with cognitive impairments, but requires approximately 10 days of training. Thus, elderly dogs are excellent experimental models to study pathological aging based on their similarities with some human brain diseases, such as Alzheimer disease. (C) 2014 Elsevier Inc. All rights reserved.
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In general, pattern recognition techniques require a high computational burden for learning the discriminating functions that are responsible to separate samples from distinct classes. As such, there are several studies that make effort to employ machine learning algorithms in the context of big data classification problems. The research on this area ranges from Graphics Processing Units-based implementations to mathematical optimizations, being the main drawback of the former approaches to be dependent on the graphic video card. Here, we propose an architecture-independent optimization approach for the optimum-path forest (OPF) classifier, that is designed using a theoretical formulation that relates the minimum spanning tree with the minimum spanning forest generated by the OPF over the training dataset. The experiments have shown that the approach proposed can be faster than the traditional one in five public datasets, being also as accurate as the original OPF. (C) 2014 Elsevier B. V. All rights reserved.
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This paper aims to contribute to the three-dimensional generalization of numerical prediction of crack propagation through the formulation of finite elements with embedded discontinuities. The analysis of crack propagation in two-dimensional problems yields lines of discontinuity that can be tracked in a relatively simple way through the sequential construction of straight line segments oriented according to the direction of failure within each finite element in the solid. In three-dimensional analysis, the construction of the discontinuity path is more complex because it requires the creation of plane surfaces within each element, which must be continuous between the elements. In the method proposed by Chaves (2003) the crack is determined by solving a problem analogous to the heat conduction problem, established from local failure orientations, based on the stress state of the mechanical problem. To minimize the computational effort, in this paper a new strategy is proposed whereby the analysis for tracking the discontinuity path is restricted to the domain formed by some elements near the crack surface that develops along the loading process. The proposed methodology is validated by performing three-dimensional analyses of basic problems of experimental fractures and comparing their results with those reported in the literature.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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This paper introduces the Optimum-Path Forest (OPF) classifier for static video summarization, being its results comparable to the ones obtained by some state-of-the-art video summarization techniques. The experimental section has been conducted using several image descriptors in two public datasets, followed by an analysis of OPF robustness regarding one ad-hoc parameter. Future works are guided to improve OPF effectiveness on each distinct video category.
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In Computer-Aided Diagnosis-based schemes in mammography analysis each module is interconnected, which directly affects the system operation as a whole. The identification of mammograms with and without masses is highly needed to reduce the false positive rates regarding the automatic selection of regions of interest for further image segmentation. This study aims to evaluate the performance of three techniques in classifying regions of interest as containing masses or without masses (without clinical findings), as well as the main contribution of this work is to introduce the Optimum-Path Forest (OPF) classifier in this context, which has never been done so far. Thus, we have compared OPF against with two sorts of neural networks in a private dataset composed by 120 images: Radial Basis Function and Multilayer Perceptron (MLP). Texture features have been used for such purpose, and the experiments have demonstrated that MLP networks have been slightly better than OPF, but the former is much faster, which can be a suitable tool for real-time recognition systems.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)