965 resultados para object modeling from images
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Real time Tritium concentrations in air in two chemical forms, HT and HTO, coming from an ITER-like fusion reactor as source were coupled the European Centre Medium Range Weather Forecast (ECMWF) numerical model with the Lagrangian Atmospheric-particle dispersion model FLEXPART. This tool was analyzed in nominal tritium discharge operational reference and selected incidental conditions affecting the Western Mediterranean Basin during 45 days during summer 2010 together with surface “wind observations” or weather data based in real hourly observations of wind direction and velocity providing a real approximation of the tritium behavior after the release to the atmosphere from a fusion reactor. From comparison with NORMTRI - a code using climatologically sequences as input - over the same area, the real time results have demonstrated an apparent overestimation of the corresponding climatologically sequence of Tritium concentrations in air outputs, at several distances from the reactor. For this purpose two development patterns were established. The first one was following a cyclonic circulation over the Mediterranean Sea and the second one was based on the plume delivered over the Interior of the Iberian Peninsula and Continental Europe by another stabilized circulation corresponding to a High Pressure System. One of the important remaining activities defined then, was the qualification tool. In order to validate the model of ECMWF/FLEXPART we have developed of a new complete data base of tritium concentrations for the months from November 2010 to March 2011 and defined a new set of four patterns of HT transport in air, in each case using real boundary conditions: stationary to the North, stationary to the South, fast and very fast displacement. Finally the differences corresponding to those four early patterns (each one in assessments 1 and 2) has been analyzed in terms of the tuning of safety related issues and taking into account the primary phase o- - f tritium modeling, from its discharge to the atmosphere to the deposition on the ground, will affect to the complete tritium environmental pathway altering the chronic dose by absorption, reemission and ingestion both from elemental tritium, HT and from the oxide of tritium, HTO
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This paper discusses the target localization problem in wireless visual sensor networks. Additive noises and measurement errors will affect the accuracy of target localization when the visual nodes are equipped with low-resolution cameras. In the goal of improving the accuracy of target localization without prior knowledge of the target, each node extracts multiple feature points from images to represent the target at the sensor node level. A statistical method is presented to match the most correlated feature point pair for merging the position information of different sensor nodes at the base station. Besides, in the case that more than one target exists in the field of interest, a scheme for locating multiple targets is provided. Simulation results show that, our proposed method has desirable performance in improving the accuracy of locating single target or multiple targets. Results also show that the proposed method has a better trade-off between camera node usage and localization accuracy.
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Vision extracts useful information from images. Reconstructing the three-dimensional structure of our environment and recognizing the objects that populate it are among the most important functions of our visual system. Computer vision researchers study the computational principles of vision and aim at designing algorithms that reproduce these functions. Vision is difficult: the same scene may give rise to very different images depending on illumination and viewpoint. Typically, an astronomical number of hypotheses exist that in principle have to be analyzed to infer a correct scene description. Moreover, image information might be extracted at different levels of spatial and logical resolution dependent on the image processing task. Knowledge of the world allows the visual system to limit the amount of ambiguity and to greatly simplify visual computations. We discuss how simple properties of the world are captured by the Gestalt rules of grouping, how the visual system may learn and organize models of objects for recognition, and how one may control the complexity of the description that the visual system computes.
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Visual responses of neurons in parietal area 7a are modulated by a combined eye and head position signal in a multiplicative manner. Neurons with multiplicative responses can act as powerful computational elements in neural networks. In the case of parietal cortex, multiplicative gain modulation appears to play a crucial role in the transformation of object locations from retinal to body-centered coordinates. It has proven difficult to uncover single-neuron mechanisms that account for neuronal multiplication. Here we show that multiplicative responses can arise in a network model through population effects. Specifically, neurons in a recurrently connected network with excitatory connections between similarly tuned neurons and inhibitory connections between differently tuned neurons can perform a product operation on additive synaptic inputs. The results suggest that parietal responses may be based on this architecture.
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Beyond the inherent technical challenges, current research into the three dimensional surface correspondence problem is hampered by a lack of uniform terminology, an abundance of application specific algorithms, and the absence of a consistent model for comparing existing approaches and developing new ones. This paper addresses these challenges by presenting a framework for analysing, comparing, developing, and implementing surface correspondence algorithms. The framework uses five distinct stages to establish correspondence between surfaces. It is general, encompassing a wide variety of existing techniques, and flexible, facilitating the synthesis of new correspondence algorithms. This paper presents a review of existing surface correspondence algorithms, and shows how they fit into the correspondence framework. It also shows how the framework can be used to analyse and compare existing algorithms and develop new algorithms using the framework's modular structure. Six algorithms, four existing and two new, are implemented using the framework. Each implemented algorithm is used to match a number of surface pairs. Results demonstrate that the correspondence framework implementations are faithful implementations of existing algorithms, and that powerful new surface correspondence algorithms can be created. (C) 2004 Elsevier Inc. All rights reserved.
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A intenção de rotatividade refere-se à probabilidade de os indivíduos deixarem o seu trabalho atual. Este tema se tornou relevante para as organizações por ser um potencial problema que pode afetar a competitividade das organizações, entre outros motivos. Acredita-se que alguns dos indivíduos com intenção de rotatividade possivelmente buscam meios de comunicação, novas tecnologias, como a rede social profissional LinkedIn objetivando disseminar suas informações profissionais, localizar oportunidades profissionais, obter mais contatos e informações sobre o mercado de trabalho, entre outras possibilidades. Desse modo, a intenção de rotatividade pode ser avaliada como um fator antecedente à adoção individual da rede social profissional LinkedIn. Este estudo analisou os fatores antecedentes que podem influenciar a intenção de uso e o comportamento de uso da rede social profissional LinkedIn, apoiando-se na perspectiva teórica da Teoria Unificada de Aceitação e Uso da Tecnologia (UTAUT), de Venkatesh et al (2003), e na escala de intenção de rotatividade, de Siqueira et al (2014) e Van Dam (2008). A pesquisa fundamenta-se em uma abordagem de investigação quantitativa na qual os dados foram coletados por meio de um instrumento de pesquisa com a obtenção de 292 questionários respondidos, o que possibilitou a validação dos relacionamentos entre os construtos componentes do modelo de pesquisa desenvolvido para o estudo da adoção individual da rede social profissional LinkedIn. Para realizar o teste das hipóteses do estudo, procedeu-se a análise de equações estruturais, com base no PLS-PM (Partial Least Squares Path Modeling) a partir do qual foram apresentadas medidas satisfatórias para os construtos investigados e o modelo proposto, sendo significativas todas as relações entre os construtos. Os resultados obtidos por esta pesquisa confirmam a influência dos fatores antecedentes Expectativa de Desempenho, Expectativa de Esforço, Influência Social e Intenção de Rotatividade na intenção de uso da rede social profissional LinkedIn. O estudo concluiu que Expectativa de Desempenho revelou-se o fator que mais influencia na intenção de uso do LinkedIn, pois há a percepção de que ao utilizar o LinkedIn pode-se obter benefícios profissionais, entre outros aspectos. O segundo fator que apresentou maior influência na intenção de uso do LinkedIn foi a intenção de rotatividade, uma vez que alguns dos indivíduos, ao adotarem o LinkedIn, provavelmente tendem a mostrar para as outras pessoas/organizações interessadas quais são os seus talentos, suas experiências, competências, além de obter mais contatos, entre outros motivos. Já a Expectativa de Esforço demonstrou que alguns indivíduos percebem que é fácil a interação desta tecnologia. A Influência Social constatou que existe a percepção dos indivíduos quanto à influência da sua rede de contatos na intenção de uso do LinkedIn.
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Purpose - To generate a reflectance model of the fundus that allows an accurate non-invasive quantification of blood and pigments. Methods - A Monte Carlo simulation was used to produce a mathematical model of light interaction with the fundus at different wavelengths. The model predictions were compared with fundus images from normal volunteers in several spectral bands (peaks at 507, 525, 552, 585, 596 and 611nm). Th e model was then used to calculate the concentration and distribution of the known absorbing components of the fundus. Results - The shape of the statistical distribution of the image data generally corresponded to that of the model data; the model however appears to overestimate the reflectance of the fundus in the longer wavelength region.As the absorption by xanthophyll has no significant eff ect on light transport above 534nm, its distribution in the fundus was quantified: the wavelengths where both shape and distribution of image and model data matched (<553nm) were used to train a neural network which was then applied to every point in the image data. The xanthophyll distribution thus found was in agreement with published literature data in normal subjects. Conclusion - We have developed a method for optimising multi-spectral imaging of the fundus and a computer image analysis capable of estimating information about the structure and properties of the fundus. Th e technique successfully calculates the distribution of xanthophyll in the fundus of healthy volunteers. Further improvement of the model is required to allow the deduction of other parameters from images; investigations in known pathology models are also necessary to establish if this method is of clinical use in detecting early chroido-retinopathies, hence providing a useful screening and diagnostic tool.
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The polyparametric intelligence information system for diagnostics human functional state in medicine and public health is developed. The essence of the system consists in polyparametric describing of human functional state with the unified set of physiological parameters and using the polyparametric cognitive model developed as the tool for a system analysis of multitude data and diagnostics of a human functional state. The model is developed on the basis of general principles geometry and symmetry by algorithms of artificial intelligence systems. The architecture of the system is represented. The model allows analyzing traditional signs - absolute values of electrophysiological parameters and new signs generated by the model – relationships of ones. The classification of physiological multidimensional data is made with a transformer of the model. The results are presented to a physician in a form of visual graph – a pattern individual functional state. This graph allows performing clinical syndrome analysis. A level of human functional state is defined in the case of the developed standard (“ideal”) functional state. The complete formalization of results makes it possible to accumulate physiological data and to analyze them by mathematics methods.
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Neural Networks have been successfully employed in different biomedical settings. They have been useful for feature extractions from images and biomedical data in a variety of diagnostic applications. In this paper, they are applied as a diagnostic tool for classifying different levels of gastric electrical uncoupling in controlled acute experiments on dogs. Data was collected from 16 dogs using six bipolar electrodes inserted into the serosa of the antral wall. Each dog underwent three recordings under different conditions: (1) basal state, (2) mild surgically-induced uncoupling, and (3) severe surgically-induced uncoupling. For each condition half-hour recordings were made. The neural network was implemented according to the Learning Vector Quantization model. This is a supervised learning model of the Kohonen Self-Organizing Maps. Majority of the recordings collected from the dogs were used for network training. Remaining recordings served as a testing tool to examine the validity of the training procedure. Approximately 90% of the dogs from the neural network training set were classified properly. However, only 31% of the dogs not included in the training process were accurately diagnosed. The poor neural-network based diagnosis of recordings that did not participate in the training process might have been caused by inappropriate representation of input data. Previous research has suggested characterizing signals according to certain features of the recorded data. This method, if employed, would reduce the noise and possibly improve the diagnostic abilities of the neural network.
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Предложена структурная модель полутонового изображения. Структурная модель предполагает инвариантное относительно аффинных преобразований описание выделенных в изображении объектов. Форма объекта полностью определяет его описание и представлена его граничным контуром и функцией оптической плотности, которая определена в пределах этого контура. Предложено определение контура полутонового изображения как последовательности, состоящей из отрезков прямых и дуг кривых, причем эти отрезки прямых и дуги кривых являются особыми линиями поверхности, которая соответствует полутоновому изображению. Рассматривается пример использования структурной модели в процессе обработки полутоновых изображений медицинских препаратов, полученных по методу Кирлиан.
Classification of Paintings by Artist, Movement, and Indoor Setting Using MPEG-7 Descriptor Features
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ACM Computing Classification System (1998): I.4.9, I.4.10.
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In this chapter we provide a comprehensive overview of the emerging field of visualising and browsing image databases. We start with a brief introduction to content-based image retrieval and the traditional query-by-example search paradigm that many retrieval systems employ. We specify the problems associated with this type of interface, such as users not being able to formulate a query due to not having a target image or concept in mind. The idea of browsing systems is then introduced as a means to combat these issues, harnessing the cognitive power of the human mind in order to speed up image retrieval.We detail common methods in which the often high-dimensional feature data extracted from images can be used to visualise image databases in an intuitive way. Systems using dimensionality reduction techniques, such as multi-dimensional scaling, are reviewed along with those that cluster images using either divisive or agglomerative techniques as well as graph-based visualisations. While visualisation of an image collection is useful for providing an overview of the contained images, it forms only part of an image database navigation system. We therefore also present various methods provided by these systems to allow for interactive browsing of these datasets. A further area we explore are user studies of systems and visualisations where we look at the different evaluations undertaken in order to test usability and compare systems, and highlight the key findings from these studies. We conclude the chapter with several recommendations for future work in this area. © 2011 Springer-Verlag Berlin Heidelberg.
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A szerző az alkalmazott többszektoros modellezés területén a lineáris programozási modellektől a számszerűsített általános egyensúlyi modellekig végbement változásokat tekinti át. Egy rövid történeti visszapillantás után a lineáris programozás módszereire épülő nemzetgazdasági szintű modellekkel összevetve mutatja be az általános egyensúlyi modellek közös, illetve eltérő jellemzőit. Egyidejűleg azt is érzékelteti, hogyan lehet az általános egyensúlyi modelleket a gazdaságpolitikai célok konzisztenciájának, a célok közötti átváltási lehetőségek elemzésére és általában a gazdaságpolitikai elképzelések érzékenységi vizsgálatára felhasználni. A szerző az elméleti-módszertani kérdések taglalását számszerűsített általános egyensúlyi modell segítségével illusztrálja. _______ The author surveys the changes having taken place in the field of multi-sector modeling, from the linear programming models to the quantified general equilibrium models. After a brief historical retrospection he presents the common and different characteristic features of the general equilibrium models by comparing them with the national economic level models based on the methods of linear programming. He also makes clear how the general equilibrium models can be used for analysing the consistency of economic policy targets, for the investigation of trade-off possibilities among the targets and, in general, for sensitivity analyses of economic policy targets. The discussion of theoretical and methodological quuestions is illustrated by the author with the aid of a quantified general equilibrium model.
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Chaconne, Transcription for Piano in D minor J.S. Bach (arr. Ferruccio Busoni) Reflets dans l'eau from Images, Book 1 Claude Debussy A la Albeniz Rodion Shchedrin Basso Ostinato from Two Polyphonic Pieces Sonata-Reminiscenza, Op. 38, No. 1 Nikolai Medtner Die Loreley, S. 532 Franz Liszt Hungarian Rhapsody No. 6