358 resultados para MAPPINGS
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We present a non-linear symplectic map that describes the alterations of the magnetic field lines inside the tokamak plasma due to the presence of a robust torus (RT) at the plasma edge. This RT prevents the magnetic field lines from reaching the tokamak wall and reduces, in its vicinity, the islands and invariant curve destruction due to resonant perturbations. The map describes the equilibrium magnetic field lines perturbed by resonances created by ergodic magnetic limiters (EMLs). We present the results obtained for twist and non-twist mappings derived for monotonic and non-monotonic plasma current density radial profiles, respectively. Our results indicate that the RT implementation would decrease the field line transport at the tokamak plasma edge. (C) 2010 Elsevier B.V. All rights reserved.
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Structured meaning-signal mappings, i.e., mappings that preserve neighborhood relationships by associating similar signals with similar meanings, are advantageous in an environment where signals are corrupted by noise and sub-optimal meaning inferences are rewarded as well. The evolution of these mappings, however, cannot be explained within a traditional language evolutionary game scenario in which individuals meet randomly because the evolutionary dynamics is trapped in local maxima that do not reflect the structure of the meaning and signal spaces. Here we use a simple game theoretical model to show analytically that when individuals adopting the same communication code meet more frequently than individuals using different codes-a result of the spatial organization of the population-then advantageous linguistic innovations can spread and take over the population. In addition, we report results of simulations in which an individual can communicate only with its K nearest neighbors and show that the probability that the lineage of a mutant that uses a more efficient communication code becomes fixed decreases exponentially with increasing K. These findings support the mother tongue hypothesis that human language evolved as a communication system used among kin, especially between mothers and offspring.
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Scenarios for the emergence or bootstrap of a lexicon involve the repeated interaction between at least two agents who must reach a consensus on how to name N objects using H words. Here we consider minimal models of two types of learning algorithms: cross-situational learning, in which the individuals determine the meaning of a word by looking for something in common across all observed uses of that word, and supervised operant conditioning learning, in which there is strong feedback between individuals about the intended meaning of the words. Despite the stark differences between these learning schemes, we show that they yield the same communication accuracy in the limits of large N and H, which coincides with the result of the classical occupancy problem of randomly assigning N objects to H words.
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The design of binary morphological operators that are translation-invariant and locally defined by a finite neighborhood window corresponds to the problem of designing Boolean functions. As in any supervised classification problem, morphological operators designed from a training sample also suffer from overfitting. Large neighborhood tends to lead to performance degradation of the designed operator. This work proposes a multilevel design approach to deal with the issue of designing large neighborhood-based operators. The main idea is inspired by stacked generalization (a multilevel classifier design approach) and consists of, at each training level, combining the outcomes of the previous level operators. The final operator is a multilevel operator that ultimately depends on a larger neighborhood than of the individual operators that have been combined. Experimental results show that two-level operators obtained by combining operators designed on subwindows of a large window consistently outperform the single-level operators designed on the full window. They also show that iterating two-level operators is an effective multilevel approach to obtain better results.
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We discuss a strong version of the Dunford-Pettis property, earlier named (DP*) property, which is shared by both l(1) and l(infinity) It is equivalent to the Dunford-Pettis property plus the fact that every quotient map onto c(0) is completely continuous. Other weak sequential continuity results on polynomials and analytic mappings related to the (DP*) property are shown.
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Given a branched covering of degree d between closed surfaces, it determines a collection of partitions of d, the branch data. In this work we show that any branch data are realized by an indecomposable primitive branched covering on a connected closed surface N with chi(N) <= 0. This shows that decomposable and indecomposable realizations may coexist. Moreover, we characterize the branch data of a decomposable primitive branched covering. Bibliography: 20 titles.
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Interoperability of water quality data depends on the use of common models, schemas and vocabularies. However, terms are usually collected during different activities and projects in isolation of one another, resulting in vocabularies that have the same scope being represented with different terms, using different formats and formalisms, and published in various access methods. Significantly, most water quality vocabularies conflate multiple concepts in a single term, e.g. quantity kind, units of measure, substance or taxon, medium and procedure. This bundles information associated with separate elements from the OGC Observations and Measurements (O&M) model into a single slot. We have developed a water quality vocabulary, formalized using RDF, and published as Linked Data. The terms were extracted from existing water quality vocabularies. The observable property model is inspired by O&M but aligned with existing ontologies. The core is an OWL ontology that extends the QUDT ontology for Unit and QuantityKind definitions. We add classes to generalize the QuantityKind model, and properties for explicit description of the conflated concepts. The key elements are defined to be sub-classes or sub-properties of SKOS elements, which enables a SKOS view to be published through standard vocabulary APIs, alongside the full view. QUDT terms are re-used where possible, supplemented with additional Unit and QuantityKind entries required for water quality. Along with items from separate vocabularies developed for objects, media, and procedures, these are linked into definitions in the actual observable property vocabulary. Definitions of objects related to chemical substances are linked to items from the Chemical Entities of Biological Interest (ChEBI) ontology. Mappings to other vocabularies, such as DBPedia, are in separately maintained files. By formalizing the model for observable properties, and clearly labelling the separate concerns, water quality observations from different sources may be more easily merged and also transformed to O&M for cross-domain applications.
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Observational data encodes values of properties associated with a feature of interest, estimated by a specified procedure. For water the properties are physical parameters like level, volume, flow and pressure, and concentrations and counts of chemicals, substances and organisms. Water property vocabularies have been assembled at project, agency and jurisdictional level. Organizations such as EPA, USGS, CEH, GA and BoM maintain vocabularies for internal use, and may make them available externally as text files. BODC and MMI have harvested many water vocabularies alongside others of interest in their domain, formalized the content using SKOS, and published them through web interfaces. Scope is highly variable both within and between vocabularies. Individual items may conflate multiple concerns (e.g. property, instrument, statistical procedure, units). There is significant duplication between vocabularies. Semantic web technologies provide the opportunity both to publish vocabularies more effectively, and achieve harmonization to support greater interoperability between datasets. - Models for vocabulary items (property, substance/taxon, process, unit-of-measure, etc) may be formalized OWL ontologies, supporting semantic relations between items in related vocabularies; - By specializing the ontology elements from SKOS concepts and properties, diverse vocabularies may be published through a common interface; - Properties from standard vocabularies (e.g. OWL, SKOS, PROV-O and VAEM) support mappings between vocabularies having a similar scope - Existing items from various sources may be assembled into new virtual vocabularies However, there are a number of challenges: - use of standard properties such as sameAs/exactMatch/equivalentClass require reasoning support; - items have been conceptualised as both classes and individuals, complicating the mapping mechanics; - re-use of items across vocabularies may conflict with expectations concerning URI patterns; - versioning complicates cross-references and re-use. This presentation will discuss ways to harness semantic web technologies to publish harmonized vocabularies, and will summarise how many of the challenges may be addressed.
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Foram analisados espectros óticos de fenda longa de 29 galáxias que hospedam núcleos ativos (AGNs), sendo 6 galáxias Seyfert 1, 18 galáxias Seyfert 2, 4 Rádio-galáxias de linhas estreitas (NLRG) e 1 Rádio-galáxia de linhas largas (BLRG). Estas galáxias apresentam emissão por gás de alta excitação que se estende em alguns casos a 10 kpc do núcleo. O objetivo do presente trabalho consiste em estudar e caracterizar as propriedades físicas da região estendida de linhas estreitas (ENLR) destes objetos bem como propriedades da fonte central. A distribuição radial de parâmetros que caracterizam o gás emissor em cada galáxia, tais como brilho superficial das linhas de emissão, densidade do gás, massa, extinção e excitação são obtidos. Estes valores característicos são comparados entre as diferentes classes de atividade nuclear presentes em nossa amostra, bem como às propriedades de galáxias normais com o mesmo tipo de Hubble quando possível. Nós encontramos que a massa de gás ionizado é consistente com a hipótese de que o gás é “originado” na fotoionização pela fonte central das nuvens de HI préexistentes na galáxia hospedeira. Os valores observados das razões entre as linhas estreitas de emissão são comparados com os obtidos através de modelos de fotoionização gerados com o código MAPPINGS Ic, obtendo os parâmetros do modelo – densidade, índice espectral da distribuição de energia e da metalicidade do gás – que melhor reproduzem as observações. Observamos que a variação da abundância química do gás é necessária para explicar o espalhamento nos valores observados. Adicionalmente, comparamos os valores observados com os obtidos com modelos de choques gerados por Dopita & Sutherland. Investigamos também a influência da emissão proveniente de regiões HII ao espectro observado – a qual concluímos ser importante particularmente nas regiões emissoras mais distantes do que 2 kpc do núcleo. Nós determinamos a luminosidade ionizante da fonte central nos AGNs usando a aproximação de que as nuvens de gás são limitadas por radiação, e obtivemos os correspondentes valores para o fator de cobertura do gás. Esta luminosidade ionizante foi então comparada com a luminosidade observada em raios-X na banda 2 –10 keV, através de aproximações para a distribuição espectral de energia (SED). Para 9 galáxias Seyfert 2 a luminosidade observada está disponível, e verificamos que nosso método recupera a luminosidade do AGN em raios-X – assim como obtida dos dados do satélite ASCA – bem como identifica os 3 casos Compton espessos. Por fim, investigamos a natureza do contínuo infravermelho (IR) médio e distante – comparandose a luminosidade observada no IR, calculada a partir dos fluxos IRAS, com a luminosidade predita para um toro que envolve a fonte central absorvendo a radiação incidente e re-emitindo esta no infravermelho. Encontramos que a luminosidade observada no IR é consistente com a luminosidade predita para o torus.
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Foram analisados espectros óticos de fenda longa das galáxias Seyfert 1 ESO362-G18 e Seyfert 2 ESO362-G8. Estas duas galáxias apresentam emissão por gás de alta excitação em forma anisotrópica, possivelmente devido a colimação por um tóro de poeira. O objetivo do presente trabalho consiste em estudar o contínuo e a região estendida de linhas de emissão (ENLR) destes objetos. Este trabalho constitui-se no primeiro estudo detalhado realizado sobre estas galáxias. A população estelar em cada galáxia e caracterizada em função da distância ao núcleo. O contínuo nuclear e estudado em termos de duas componentes: a população estelar e a componente AGN (\Active Galatic Nuclei"). Observa-se a presença desta componente AGN na gal axia Seyfert 1 ESO362-G18. A galáxia Seyfert 2 não permite observar esta componente AGN mesmo depois de subtraída a componente de população estelar. Nas duas galáxias observa-se importante contribuição de população de idade intermediária ( 5 108 anos). A partir das linhas estreitas de emissão, mapeamos a excitação do gás interestelar ao longo da ENLR. As razões entre estas linhas de emissão são reproduzidas a partir de um modelo de fotoionização de duas componentes - uma componente limitada por matéria ("matter-bounded") e uma componente limitada por ionização ("ionization-bounded"). Este modelo, construído utilizando o código de fotoionização MAPPINGS Ic, se propõe a resolver os problemas apresentados pelos modelos tradicionais de uma componente apenas. A partir dos resultados obtidos com o modelo de duas componentes, determinamos o fator de preenchimento e o fator de cobertura do gás em função da distância ao núcleo. Utilizamos estes parâmetros para testar a consistência do modelo proposto. Por fim realizase o cálculo de balanço de fótons e estuda-se a natureza do contínuo infravermelho (IR) médio e distante - comparando-se a luminosidade observada no IR, calculada a partir dos fluxos IRAS, com a luminosidade predita para um tóro que envolve a fonte modelada e re-emite a radiação incidente no infravermelho.
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Why don’t agents cooperate when they both stand to gain? This question ranks among the most fundamental in the social sciences. Explanations abound. Among the most compelling are various configurations of the prisoner’s dilemma (PD), or public goods problem. Payoffs in PD’s are specified in one of two ways: as primitive cardinal payoffs or as ordinal final utility. However, as final utility is objectively unobservable, only the primitive payoff games are ever observed. This paper explores mappings from primitive payoff to utility payoff games and demonstrates that though an observable game is a PD there are broad classes of utility functions for which there exists no associated utility PD. In particular we show that even small amounts of either altruism or enmity may disrupt the mapping from primitive payoff to utility PD. We then examine some implications of these results.
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O papel dos municípios na garantia da provisão de serviços de saúde no âmbito do Sistema Único de Saúde é crescente, sendo cada vez mais necessário repensar novas formas de financiamento e apoio para fortalecer uma gestão mais eficiente e racional. Esse trabalho vem no sentido de identificar como os municípios estão garantindo essa provisão, dentro de um cenário de restrição orçamentária imposto pelos limites com despesas de pessoal. A metodologia conta com uma primeira abordagem exploratória dos gastos municipais, que revelaram impactos, sendo o principal o aumento das despesas com terceiros após a aprovação da Lei de Responsabilidade Fiscal. A partir dessa análise foi elaborada uma amostra representativa dos municípios do Estado de São Paulo, para detectar como eles conduzem a execução da política de saúde, por meio de entrevistas e de levantamento de informações sobre as formas de contratação de pessoas e serviços no âmbito municipal, ambas recolhidas junto a gestores municipais. Os resultados reforçam a necessidade de investimentos que contemplem as desigualdades intermunicipais e o questionamento no estabelecimento de limites iguais em realidades totalmente desiguais.
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Why don't agents cooperate when they both stand to gain? This question ranks among the most fundamental in the social sciences. Explanations abound. Among the most compelling are various configurations of the prisonerís dilemma (PD), or public goods problem. Payoffs in PDís are specified in one of two ways: as primitive cardinal payoffs or as ordinal final utility. However, as final utility is objectively unobservable, only the primitive payoff games are ever observed. This paper explores mappings from primitive payoff to utility payoff games and demonstrates that though an observable game is a PD there are broad classes of utility functions for which there exists no associated utility PD. In particular we show that even small amounts of either altruism or jealousy may disrupt the mapping from primitive payoff to utility PD. We then examine some implications of these results ñ including the possibility of conflict inducing growth.
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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The quarrel on the urban intensific use of determined areas of the city is carried through in some levels of the society, which had to the fact to bring direct influences the population that inhabits it. The question to become an area to intensific use, implies in determining that the local infrastructure has the capacity to take care of to a bigger amount of people, inhabitants or passers-by. In the quarter of Ponta Negra, in Natal city (state of RN), its condition of area to intensific use to the municipal Law 27/2000 happened due that it starts to allow a bigger level of occupation of part of the quarter. This law has a direct relation with the installation of a complementary infrastructure in the quarter, to put does not send to its complementation and maintenance, what it takes the consequences that are felt by the population. This work has as main objective the identification of the decurrent significant consequences of the creation of Ponta Negra s Intensific Use Zone, according to vision of the population of the quarter. The way followed for this involves the compatible bibliography research with the subject, analysis of documents that treat on the quarter, mappings of the area in search of a physical characterization and mainly, an application of questionnaire next to local population. In this questionnaire it is the main point of the necessary collection of data to the work, indicating the point of view of the population not only on the negative points, but also on the positive points that had happened since the creation of Intensific Use Zone. The answers indicate problems of natures social, infrastructure and enviromental, compatible with the problems of other areas that had passed the same for process, as point the studied bibliography, indicating imperfections in the planning process and maintenance of Ponta Negra s Intensific Use Zone