932 resultados para market information processing


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Las valoraciones automatizadas (AVM según sus siglas en inglés) son modelos matemáticos de valoración que permiten estimar el valor de un inmueble o una cartera de inmuebles mediante la utilización de información de mercado previamente recogida y analizada. Las principales ventajas de los modelos AVM respecto a las valoraciones tradicionales son su objetividad, rapidez y economía. Existe regulación al respecto y estándares profesionales en otros países, no obstante en España los criterios de valoración mediante modelos AVM siguen siendo excesivamente básicos, al no establecer procesos concretos ni distinguir entre los diversos métodos estadísticos existentes y la aplicación adecuada de los mismos. Por otra parte, desde la publicación de la Circular 3/2008 del Banco de España se ha extendido el uso de este tipo de valoraciones en España para la actualización de valor de inmuebles en garantía de préstamos hipotecarios. La actual desregularización en nuestro país en cuanto a normativa de valoraciones automatizadas nos permite plantear propuestas y metodologías con el fin de aportar un punto de vista nuevo desde la investigación, la experiencia en otros países y la práctica empresarial más reciente. Este trabajo de investigación trata de sentar las bases de una futura regulación en España en materia de valoraciones masivas adaptadas al marco hipotecario español. ABSTRACT The Automated Valuation Models (AVM) are mathematically based valuation models that allow to estimate the value of a property or portfolio of properties by using market information previously collected and analyzed. The main advantages of the AVMs in comparison to traditional valuations are the objectivity, speed and economy. In other countries there is regulation and standards regarding the use of AVMs. However, in Spain the norms that apply to AVM valuations are still too basic, since these norms do not define specific processes and do not distinguish between the different statistical approaches available and their correct use. On the other hand, following the ratification of the 3/2008 Bank of Spain Circular the use of AVM models in Spain for the value update of mortgaged properties has increased. The current deregulation in Spain regarding Automated Valuation Models allows to provide propositions and methodologies in order to offer a new point of view based on the research, experience in other countries and the most recent professional practice. The present research thesis aims to provide basic principles and criteria for a future Spanish regulation on massive valuation in the context of the Spanish mortgage framework.

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Vivemos um período de transformações políticas, econômicas, sociais e culturais que, a todo instante, nos impõe desafios. Neste contexto, nas últimas décadas, o uso da tecnologia tem sido ampliado na realização de diversas atividades cotidianas, na divulgação de informações, na comunicação, como forma de expressão e organização da sociedade. A escola, enquanto instituição social, precisa reconhecer esta nova realidade, esta diferente possibilidade de aquisição e transformação de saber, para que possa intervir, ressignificar e redirecionar sua ação, a fim de atender as demandas de seu tempo. O objetivo geral desta pesquisa, a partir da apresentação e análise de experiências realizadas com o uso de Tecnologias da Informação e Conhecimento, é o de refletir sobre como inserir estas ferramentas no processo de ensinar e aprender na escola a partir da visão de professores e alunos, visando a formação integral do educando. Deste modo, no desenvolvimento, entendemos como necessário conhecer e considerar o contexto histórico, bem como as perspectivas relacionadas a escola e seus protagonistas (professores e estudantes) na chamada Sociedade da Informação e do Conhecimento. Ressaltamos a importância do docente (sua formação) e seu papel de mediador nos processos de aprendizagem, assim como a recepção à tecnologia, observando função e espaço de atuação desta. Destacamos experiências com a utilização de TDIC, realizada por professores e alunos, como a produção de game, revistas científicas, escrita de histórias, produções artísticas, blogs, vlogs, discussões em grupos presentes em redes sociais. A metodologia utilizada nesta pesquisa é qualitativa, na modalidade de pesquisa-ação e narrativa, em função do envolvimento com o grupo e com as atividades desenvolvidas, nas quais os participantes compartilham com o pesquisador suas histórias pessoais e de aprendizagem relacionadas às ações ou às atividades que realiza, fornecendo informações e indícios relevantes sobre o seu processo de formação ao longo do tempo. A revisão de literatura foi realizada por meio de análise bibliográfica e documental em livros, teses, dissertações, periódicos específicos sobre o assunto, além de artigos publicados na Internet. A coleta de dados foi realizada a partir de conversas informais, entrevistas semiestruturadas e filmagem dos relatos. A análise foi realizada a partir da abordagem hermenêutico-fenomenológica, que busca descrever e interpretar fenômenos da experiência humana, a fim de investigar a essência por meio da identificação de temas. Os resultados apontam para a necessidade e possibilidade da ampliação da utilização de TDIC como recurso no processo de ensino e aprendizagem, por meio de formação, diálogo, interação, intencionalidade, expectativas, esperança e seus desdobramentos.

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A prática do ioga tem se tornado cada vez mais popular, não apenas pelos benefícios físicos, mas principalmente pelo bem-estar psicológico trazido pela sua prática. Um dos componentes do ioga é o Prãnãyama, ou controle da respiração. A atenção e a respiração são dois mecanismos fisiológicos e involuntários requeridos para a execução do Prãnãyama. O principal objetivo desse estudo foi verificar se variáveis contínuas do EEG (potência de diferentes faixas que o compõem) seriam moduladas pelo controle respiratório, comparando-se separadamente as duas fases do ciclo respiratório (inspiração e expiração), na situação de respiração espontânea e controlada. Fizeram parte do estudo 19 sujeitos (7 homens/12 mulheres, idade média de 36,89 e DP = ± 14,46) que foram convidados a participar da pesquisa nas dependências da Faculdade de Saúde da Universidade Metodista de São Paulo. Para o registro do eletroencefalograma foi utilizado um sistema de posicionamento de cinco eletrodos Ag AgCl (FPz, Fz, Cz, Pz e Oz) fixados a uma touca de posicionamento rápido (Quick-Cap, Neuromedical Supplies®), em sistema 10-20. Foram obtidos valores de máxima amplitude de potência (espectro de potência no domínio da frequência) nas frequências teta, alfa e beta e delta e calculada a razão teta/beta nas diferentes fases do ciclo respiratório (inspiração e expiração), separadamente, nas condições de respiração espontânea e de controle respiratório. Para o registro do ciclo respiratório, foi utilizada uma cinta de esforço respiratório M01 (Pletismógrafo). Os resultados mostram diferenças significativas entre as condições de respiração espontânea e de controle com valores das médias da razão teta/beta menores na respiração controlada do que na respiração espontânea e valores de média da potência alfa sempre maiores no controle respiratório. Diferenças significativas foram encontradas na comparação entre inspiração e expiração da respiração controlada com diminuição dos valores das médias da razão teta/beta na inspiração e aumento nos valores das médias da potência alfa, sobretudo na expiração. Os achados deste estudo trazem evidências de que o controle respiratório modula variáveis eletrofisiológicas relativas à atenção refletindo um estado de alerta, porém mais relaxado do que na situação de respiração espontânea.

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O trabalho tem como proposta avaliar a postura das organizações nas mídias sociais digitais, considerando o fato de que esses novos ambientes virtuais têm modificado drasticamente a maneira pela qual elas promovem o relacionamento com seus públicos estratégicos. O objetivo principal da pesquisa é identificar e compreender como as organizações se posicionam diante de comentários desfavoráveis nas mídias sociais digitais que possam impactar sua imagem e reputação, bem como mostrar a importância de monitorar constantemente o consumidor e dialogar com ele nos canais digitais para evitar riscos à marca. A metodologia aplicada denomina-se Estudo de Casos Múltiplos, por meio da qual analisaram-se os comentários desfavoráveis às marcas: Vivo, Tim e Oi, na página do Facebook, durante o mês de setembro de 2015. Construiu-se um protocolo de pesquisa, e realizou-se o acompanhamento dessas marcas analisando-lhes os posts e os comentários desfavoráveis coletados no período. Constatou-se, após tais procedimentos que as operadoras apresentam frequentemente dificuldades para se relacionar com os públicos nas mídias sociais digitais, o que as coloca em risco quanto à sua imagem e reputação.

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A genetic annealing model for the universal ancestor of all extant life is presented; the name of the model derives from its resemblance to physical annealing. The scenario pictured starts when “genetic temperatures” were very high, cellular entities (progenotes) were very simple, and information processing systems were inaccurate. Initially, both mutation rate and lateral gene transfer levels were elevated. The latter was pandemic and pervasive to the extent that it, not vertical inheritance, defined the evolutionary dynamic. As increasingly complex and precise biological structures and processes evolved, both the mutation rate and the scope and level of lateral gene transfer, i.e., evolutionary temperature, dropped, and the evolutionary dynamic gradually became that characteristic of modern cells. The various subsystems of the cell “crystallized,” i.e., became refractory to lateral gene transfer, at different stages of “cooling,” with the translation apparatus probably crystallizing first. Organismal lineages, and so organisms as we know them, did not exist at these early stages. The universal phylogenetic tree, therefore, is not an organismal tree at its base but gradually becomes one as its peripheral branchings emerge. The universal ancestor is not a discrete entity. It is, rather, a diverse community of cells that survives and evolves as a biological unit. This communal ancestor has a physical history but not a genealogical one. Over time, this ancestor refined into a smaller number of increasingly complex cell types with the ancestors of the three primary groupings of organisms arising as a result.

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Recent studies of corticofugal modulation of auditory information processing indicate that cortical neurons mediate both a highly focused positive feedback to subcortical neurons “matched” in tuning to a particular acoustic parameter and a widespread lateral inhibition to “unmatched” subcortical neurons. This cortical function for the adjustment and improvement of subcortical information processing is called egocentric selection. Egocentric selection enhances the neural representation of frequently occurring signals in the central auditory system. For our present studies performed with the big brown bat (Eptesicus fuscus), we hypothesized that egocentric selection adjusts the frequency map of the inferior colliculus (IC) according to auditory experience based on associative learning. To test this hypothesis, we delivered acoustic stimuli paired with electric leg stimulation to the bat, because such paired stimuli allowed the animal to learn that the acoustic stimulus was behaviorally important and to make behavioral and neural adjustments based on the acquired importance of the acoustic stimulus. We found that acoustic stimulation alone evokes a change in the frequency map of the IC; that this change in the IC becomes greater when the acoustic stimulation is made behaviorally relevant by pairing it with electrical stimulation; that the collicular change is mediated by the corticofugal system; and that the IC itself can sustain the change evoked by the corticofugal system for some time. Our data support the hypothesis.

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Childhood exposure to low-level lead can permanently reduce intelligence, but the neurobiologic mechanism for this effect is unknown. We examined the impact of lead exposure on the development of cortical columns, using the rodent barrel field as a model. In all areas of mammalian neocortex, cortical columns constitute a fundamental structural unit subserving information processing. Barrel field cortex contains columnar processing units with distinct clusters of layer IV neurons that receive sensory input from individual whiskers. In this study, rat pups were exposed to 0, 0.2, 1, 1.5, or 2 g/liter lead acetate in their dam's drinking water from birth through postnatal day 10. This treatment, which coincides with the development of segregated columns in the barrel field, produced blood lead concentrations from 1 to 31 μg/dl. On postnatal day 10, the area of the barrel field and of individual barrels was measured. A dose-related reduction in barrel field area was observed (Pearson correlation = −0.740; P < 0.001); mean barrel field area in the highest exposure group was decreased 12% versus controls. Individual barrels in the physiologically more active caudoventral group were affected preferentially. Total cortical area measured in the same sections was not altered significantly by lead exposure. These data support the hypothesis that lead exposure may impair the development of columnar processing units in immature neocortex. We demonstrate that low levels of blood lead, in the range seen in many impoverished inner-city children, cause structural alterations in a neocortical somatosensory map.

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Neocortex, a new and rapidly evolving brain structure in mammals, has a similar layered architecture in species over a wide range of brain sizes. Larger brains require longer fibers to communicate between distant cortical areas; the volume of the white matter that contains long axons increases disproportionally faster than the volume of the gray matter that contains cell bodies, dendrites, and axons for local information processing, according to a power law. The theoretical analysis presented here shows how this remarkable anatomical regularity might arise naturally as a consequence of the local uniformity of the cortex and the requirement for compact arrangement of long axonal fibers. The predicted power law with an exponent of 4/3 minus a small correction for the thickness of the cortex accurately accounts for empirical data spanning several orders of magnitude in brain sizes for various mammalian species, including human and nonhuman primates.

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Motifs of neural circuitry seem surprisingly conserved over different areas of neocortex or of paleocortex, while performing quite different sensory processing tasks. This apparent paradox may be resolved by the fact that seemingly different problems in sensory information processing are related by transformations (changes of variables) that convert one problem into another. The same basic algorithm that is appropriate to the recognition of a known odor quality, independent of the strength of the odor, can be used to recognize a vocalization (e.g., a spoken syllable), independent of whether it is spoken quickly or slowly. To convert one problem into the other, a new representation of time sequences is needed. The time that has elapsed since a recent event must be represented in neural activity. The electrophysiological hallmarks of cells that are involved in generating such a representation of time are discussed. The anatomical relationships between olfactory and auditory pathways suggest relevant experiments. The neurophysiological mechanism for the psychophysical logarithmic encoding of time duration would be of direct use for interconverting olfactory and auditory processing problems. Such reuse of old algorithms in new settings and representations is related to the way that evolution develops new biochemistry.

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In optimal foraging theory, search time is a key variable defining the value of a prey type. But the sensory-perceptual processes that constrain the search for food have rarely been considered. Here we evaluate the flight behavior of bumblebees (Bombus terrestris) searching for artificial flowers of various sizes and colors. When flowers were large, search times correlated well with the color contrast of the targets with their green foliage-type background, as predicted by a model of color opponent coding using inputs from the bees' UV, blue, and green receptors. Targets that made poor color contrast with their backdrop, such as white, UV-reflecting ones, or red flowers, took longest to detect, even though brightness contrast with the background was pronounced. When searching for small targets, bees changed their strategy in several ways. They flew significantly slower and closer to the ground, so increasing the minimum detectable area subtended by an object on the ground. In addition, they used a different neuronal channel for flower detection. Instead of color contrast, they used only the green receptor signal for detection. We relate these findings to temporal and spatial limitations of different neuronal channels involved in stimulus detection and recognition. Thus, foraging speed may not be limited only by factors such as prey density, flight energetics, and scramble competition. Our results show that understanding the behavioral ecology of foraging can substantially gain from knowledge about mechanisms of visual information processing.

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Two and a half millennia ago Pythagoras initiated the scientific study of the pitch of sounds; yet our understanding of the mechanisms of pitch perception remains incomplete. Physical models of pitch perception try to explain from elementary principles why certain physical characteristics of the stimulus lead to particular pitch sensations. There are two broad categories of pitch-perception models: place or spectral models consider that pitch is mainly related to the Fourier spectrum of the stimulus, whereas for periodicity or temporal models its characteristics in the time domain are more important. Current models from either class are usually computationally intensive, implementing a series of steps more or less supported by auditory physiology. However, the brain has to analyze and react in real time to an enormous amount of information from the ear and other senses. How is all this information efficiently represented and processed in the nervous system? A proposal of nonlinear and complex systems research is that dynamical attractors may form the basis of neural information processing. Because the auditory system is a complex and highly nonlinear dynamical system, it is natural to suppose that dynamical attractors may carry perceptual and functional meaning. Here we show that this idea, scarcely developed in current pitch models, can be successfully applied to pitch perception.

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Computational neuroscience has contributed significantly to our understanding of higher brain function by combining experimental neurobiology, psychophysics, modeling, and mathematical analysis. This article reviews recent advances in a key area: neural coding and information processing. It is shown that synapses are capable of supporting computations based on highly structured temporal codes. Such codes could provide a substrate for unambiguous representations of complex stimuli and be used to solve difficult cognitive tasks, such as the binding problem. Unsupervised learning rules could generate the circuitry required for precise temporal codes. Together, these results indicate that neural systems perform a rich repertoire of computations based on action potential timing.

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The Brn-3 subfamily of POU domain genes are expressed in sensory neurons and in select brainstem nuclei. Earlier work has shown that targeted deletion of the Brn-3b and Brn-3c genes produce, respectively, defects in the retina and in the inner ear. We show herein that targeted deletion of the Brn-3a gene results in defective suckling and in uncoordinated limb and trunk movements, leading to early postnatal death. Brn-3a (-/-) mice show a loss of neurons in the trigeminal ganglia, the medial habenula, the red nucleus, and the caudal region of the inferior olivary nucleus but not in the retina and dorsal root ganglia. In the trigeminal and dorsal root ganglia, but not in the retina, there is a marked decrease in the frequency of neurons expressing Brn-3b and Brn-3c, suggesting that Brn-3a positively regulates Brn-3b and Brn-3c expression in somatosensory neurons. Thus, Brn-3a exerts its major developmental effects in somatosensory neurons and in brainstem nuclei involved in motor control. The pheno-types of Brn-3a, Brn-3b, and Brn-3c mutant mice indicate that individual Brn-3 genes have evolved to control development in the auditory, visual, or somatosensory systems and that despite differences between these systems in transduction mechanisms, sensory organ structures, and central information processing, there may be fundamental homologies in the genetic regulatory events that control their development.

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A simple evolutionary process can discover sophisticated methods for emergent information processing in decentralized spatially extended systems. The mechanisms underlying the resulting emergent computation are explicated by a technique for analyzing particle-based logic embedded in pattern-forming systems. Understanding how globally coordinated computation can emerge in evolution is relevant both for the scientific understanding of natural information processing and for engineering new forms of parallel computing systems.

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Advances in digital speech processing are now supporting application and deployment of a variety of speech technologies for human/machine communication. In fact, new businesses are rapidly forming about these technologies. But these capabilities are of little use unless society can afford them. Happily, explosive advances in microelectronics over the past two decades have assured affordable access to this sophistication as well as to the underlying computing technology. The research challenges in speech processing remain in the traditionally identified areas of recognition, synthesis, and coding. These three areas have typically been addressed individually, often with significant isolation among the efforts. But they are all facets of the same fundamental issue--how to represent and quantify the information in the speech signal. This implies deeper understanding of the physics of speech production, the constraints that the conventions of language impose, and the mechanism for information processing in the auditory system. In ongoing research, therefore, we seek more accurate models of speech generation, better computational formulations of language, and realistic perceptual guides for speech processing--along with ways to coalesce the fundamental issues of recognition, synthesis, and coding. Successful solution will yield the long-sought dictation machine, high-quality synthesis from text, and the ultimate in low bit-rate transmission of speech. It will also open the door to language-translating telephony, where the synthetic foreign translation can be in the voice of the originating talker.