972 resultados para iterated local search
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This study, now on presentation, comes as a result of a special relationship established with East Timor. Not necessarily through the several historical presences in that territory but, above all, through the emotional and personal relationships with some of the political and religious leaders of this young country. An invitation, made in 2007 by Xanana Gusmão, led us throughout the whole territory in a short time of three weeks, running the summer of 2008. Its purpose was the analysis, on the ground, of the possibility of installing local administration in a country which had recently became independent. Timor, as a result of its history, but mostly of the anthropological characteristics of its people, is an openly multicultural nation. The ancestral origins of their communities, its scattered kingdoms that spray along such a small territory, its leaders and many dialects, associated with the long portuguese presence, as well as other occupations made by foreign countries, especially Indonesia, became a cultural melting pot truly unique. Here and there we heard the people and interviewed and met the 432 local elected leaders of the country. We interviewed village elders and meet with politicians, priests, teachers and journalists. We have interpreted, or tried to, the actual conditions and cautions that must be observed in preparing the legal framework to govern the municipality in East Timor: its elective, functional, financial and oversight aspects. We have reviewed Timor’s history and took Cape Verde’s example as an international reference on its public administration, mostly its local authorities. We made also the obvious reference to the portuguese local government’s history. From search, and much of the observed and studied, remains a selfless contribution to the implementation of local government in East Timor, with alerts that incorporate conclusions and suggestions.
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We propose a stylized model of a problem-solving organization whoseinternal communication structure is given by a fixed network. Problemsarrive randomly anywhere in this network and must find their way to theirrespective specialized solvers by relying on local information alone.The organization handles multiple problems simultaneously. For this reason,the process may be subject to congestion. We provide a characterization ofthe threshold of collapse of the network and of the stock of foatingproblems (or average delay) that prevails below that threshold. We buildupon this characterization to address a design problem: the determinationof what kind of network architecture optimizes performance for any givenproblem arrival rate. We conclude that, for low arrival rates, the optimalnetwork is very polarized (i.e. star-like or centralized ), whereas it islargely homogenous (or decentralized ) for high arrival rates. We also showthat, if an auxiliary assumption holds, the transition between these twoopposite structures is sharp and they are the only ones to ever qualify asoptimal.
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Cortical folding (gyrification) is determined during the first months of life, so that adverse events occurring during this period leave traces that will be identifiable at any age. As recently reviewed by Mangin and colleagues(2), several methods exist to quantify different characteristics of gyrification. For instance, sulcal morphometry can be used to measure shape descriptors such as the depth, length or indices of inter-hemispheric asymmetry(3). These geometrical properties have the advantage of being easy to interpret. However, sulcal morphometry tightly relies on the accurate identification of a given set of sulci and hence provides a fragmented description of gyrification. A more fine-grained quantification of gyrification can be achieved with curvature-based measurements, where smoothed absolute mean curvature is typically computed at thousands of points over the cortical surface(4). The curvature is however not straightforward to comprehend, as it remains unclear if there is any direct relationship between the curvedness and a biologically meaningful correlate such as cortical volume or surface. To address the diverse issues raised by the measurement of cortical folding, we previously developed an algorithm to quantify local gyrification with an exquisite spatial resolution and of simple interpretation. Our method is inspired of the Gyrification Index(5), a method originally used in comparative neuroanatomy to evaluate the cortical folding differences across species. In our implementation, which we name local Gyrification Index (lGI(1)), we measure the amount of cortex buried within the sulcal folds as compared with the amount of visible cortex in circular regions of interest. Given that the cortex grows primarily through radial expansion(6), our method was specifically designed to identify early defects of cortical development. In this article, we detail the computation of local Gyrification Index, which is now freely distributed as a part of the FreeSurfer Software (http://surfer.nmr.mgh.harvard.edu/, Martinos Center for Biomedical Imaging, Massachusetts General Hospital). FreeSurfer provides a set of automated reconstruction tools of the brain's cortical surface from structural MRI data. The cortical surface extracted in the native space of the images with sub-millimeter accuracy is then further used for the creation of an outer surface, which will serve as a basis for the lGI calculation. A circular region of interest is then delineated on the outer surface, and its corresponding region of interest on the cortical surface is identified using a matching algorithm as described in our validation study(1). This process is repeatedly iterated with largely overlapping regions of interest, resulting in cortical maps of gyrification for subsequent statistical comparisons (Fig. 1). Of note, another measurement of local gyrification with a similar inspiration was proposed by Toro and colleagues(7), where the folding index at each point is computed as the ratio of the cortical area contained in a sphere divided by the area of a disc with the same radius. The two implementations differ in that the one by Toro et al. is based on Euclidian distances and thus considers discontinuous patches of cortical area, whereas ours uses a strict geodesic algorithm and include only the continuous patch of cortical area opening at the brain surface in a circular region of interest.
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ETHNOPHARMACOLOGICAL RELEVANCE: The aim of this survey was to describe which traditional medicines (TM) are most commonly used for non-communicable diseases (NCD - diabetes, hypertension related to excess weight and obesity) in Pacific islands and with what perceived effectiveness. NCD, especially prevalent in the Pacific, have been subject to many public health interventions, often with rather disappointing results. Innovative interventions are required; one hypothesis is that some local, traditional approaches may have been overlooked. MATERIALS AND METHODS: The method used was a retrospective treatment-outcome study in a nation-wide representative sample of the adult population (about 15,000 individuals) of the Republic of Palau, an archipelago of Micronesia. RESULTS: From 188 respondents (61% female, age 16-87, median 48,), 30 different plants were used, mostly self-prepared (69%), or from a traditional healer (18%). For excess weight, when comparing the two most frequent plants, Morinda citrifolia L. was associated with more adequate outcome than Phaleria nishidae Kaneh. (P=0.05). In case of diabetes, when comparing Phaleria nishidae (=Phaleria nisidai) and Morinda citrifolia, the former was statistically more often associated with the reported outcome "lower blood sugar" (P=0.01). CONCLUSIONS: Statistical association between a plant used and reported outcome is not a proof of effectiveness or safety, but it can help select plants of interest for further studies, e.g. through a reverse pharmacology process, in search of local products which may have a positive impact on population health.
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This paper describes Question Waves, an algorithm that can be applied to social search protocols, such as Asknext or Sixearch. In this model, the queries are propagated through the social network, with faster propagation through more trustable acquaintances. Question Waves uses local information to make decisions and obtain an answer ranking. With Question Waves, the answers that arrive first are the most likely to be relevant, and we computed the correlation of answer relevance with the order of arrival to demonstrate this result. We obtained correlations equivalent to the heuristics that use global knowledge, such as profile similarity among users or the expertise value of an agent. Because Question Waves is compatible with the social search protocol Asknext, it is possible to stop a search when enough relevant answers have been found; additionally, stopping the search early only introduces a minimal risk of not obtaining the best possible answer. Furthermore, Question Waves does not require a re-ranking algorithm because the results arrive sorted
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Peer-reviewed
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En el año 2007 el Instituto Rosarista de Acción Social y varios profesores de distintas facultades, en un esfuerzo por integrar la docencia, la investigación y la extensión, crean el Equipo interdisciplinario de estudios en desarrollo local. La iniciativa buscaba contribuir a la formulación de respuestas a problemáticas del desarrollo local por medio de la implementación de proyectos en una comunidad. Para ello, los profesores articularon sus capacidades y conocimientos en la construcción de un programa de intervención integral en el sector de El Codito. La búsqueda por construir, desde un análisis integral, procesos que atiendan los retos que impone el subdesarrollo, hace que la propuesta del Equipo Interdisciplinario sea muy interesante. Es por eso que en el capítulo 1de esta sistematización se considera pertinente rescatar las acciones del equipo a través de una sistematización de su experiencia desde sus inicios en el año 2007, hasta su desintegración en el 2013. En los capítulos 2 y 3, de manera detallada, se recoge el diagnóstico, la planificación y la ejecución de dos de los proyectos que se implementaron en el sector de El Codito: la “Escuela juvenil de formación en democracia, proyectos sociales y trabajo comunitario para el sector El Codito” e “Imaginarios y representaciones sociales en torno a la discapacidad en comunidades vulnerables. Estudio de caso sector El Codito, Bogotá.”. Por último, se presentan algunas conclusiones, lecciones aprendidas y recomendaciones de esta experiencia de trabajo comunitario.
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Empirical orthogonal functions (EOFs) are widely used in climate research to identify dominant patterns of variability and to reduce the dimensionality of climate data. EOFs, however, can be difficult to interpret. Rotated empirical orthogonal functions (REOFs) have been proposed as more physical entities with simpler patterns than EOFs. This study presents a new approach for finding climate patterns with simple structures that overcomes the problems encountered with rotation. The method achieves simplicity of the patterns by using the main properties of EOFs and REOFs simultaneously. Orthogonal patterns that maximise variance subject to a constraint that induces a form of simplicity are found. The simplified empirical orthogonal function (SEOF) patterns, being more 'local'. are constrained to have zero loadings outside the main centre of action. The method is applied to winter Northern Hemisphere (NH) monthly mean sea level pressure (SLP) reanalyses over the period 1948-2000. The 'simplified' leading patterns of variability are identified and compared to the leading patterns obtained from EOFs and REOFs. Copyright (C) 2005 Royal Meteorological Society.
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This paper deals with the design of optimal multiple gravity assist trajectories with deep space manoeuvres. A pruning method which considers the sequential nature of the problem is presented. The method locates feasible vectors using local optimization and applies a clustering algorithm to find reduced bounding boxes which can be used in a subsequent optimization step. Since multiple local minima remain within the pruned search space, the use of a global optimization method, such as Differential Evolution, is suggested for finding solutions which are likely to be close to the global optimum. Two case studies are presented.
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Much is known about the functional mechanisms involved in visual search. Yet, the fundamental question of whether the visual system can perform different types of visual analysis at different spatial resolutions still remains unsettled. In the visual-attention literature, the distinction between different spatial scales of visual processing corresponds to the distinction between distributed and focused attention. Some authors have argued that singleton detection can be performed in distributed attention, whereas others suggest that even such a simple visual operation involves focused attention. Here we showed that microsaccades were spatially biased during singleton discrimination but not during singleton detection. The results provide support to the hypothesis that some coarse visual analysis can be performed in a distributed attention mode.
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Firms outsource through connecting to local and global supply bases and making such connections produces costs of search and evaluation, which are a function of transaction characteristics and firm capabilities. We argue that firms outsource more when those costs are low. Hence, domestic subsidiaries of multinational firms, with low cost access to both local and global supply bases, outsource more than either domestic firms or foreign subsidiaries, as confirmed by evidence from a large data panel. We also propose that among foreign subsidiaries, distance from the home country co-determines search and evaluation costs such that subsidiaries from more distant countries outsource less. This is confirmed for geographic distance, but a positive effect is found for political distance and a mixed effect for cultural distance.
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Brazil`s State of Sao Paulo Research Foundation
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We present parallel algorithms on the BSP/CGM model, with p processors, to count and generate all the maximal cliques of a circle graph with n vertices and m edges. To count the number of all the maximal cliques, without actually generating them, our algorithm requires O(log p) communication rounds with O(nm/p) local computation time. We also present an algorithm to generate the first maximal clique in O(log p) communication rounds with O(nm/p) local computation, and to generate each one of the subsequent maximal cliques this algorithm requires O(log p) communication rounds with O(m/p) local computation. The maximal cliques generation algorithm is based on generating all maximal paths in a directed acyclic graph, and we present an algorithm for this problem that uses O(log p) communication rounds with O(m/p) local computation for each maximal path. We also show that the presented algorithms can be extended to the CREW PRAM model.
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This essay aims to discuss local development under the prospect of coordinated intervention of multiple organizations, considering different thematic areas of action, different economic sectors and regions of origin; structured in different methodologies and owners of different social technologies field of expertises. Search to identify determinants, facilitators, and restrictive factors of cross sectorial and cross organizational coordination processes for a common purpose. The field research was conducted at a region of State of Minas Gerais, Brazil, where a group of 13 organizations that fit the profile described above, joined up to work jointly, facilitating the environment for local development. The region is between those with the lowest incomes in Brazil. The objective of this study was to verifry what extent the practices implemented by the organizations context (the municipality in question has population of less than 40.000 inhabitants), are contributing to the formation and / or strengthening of a local scene of more opportunities that compete for the quality of life of the population. To meet this goal were interviewd 52 citizens between representatives of organizations, the government, civil society and citizens directly benefit from the Sustainable Araçuaí iniciative, using the semi-structured interview. The result has been the relationship between partnerships determining factors, facilitators and restrictive labour, structured on a conceptual map, and the perception of the impact that these actions have caused coordinates the council from the perspective of the interviewees