980 resultados para conceptual representation


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Semantic Web Mining aims at combining the two fast-developing research areas Semantic Web and Web Mining. This survey analyzes the convergence of trends from both areas: Growing numbers of researchers work on improving the results of Web Mining by exploiting semantic structures in the Web, and they use Web Mining techniques for building the Semantic Web. Last but not least, these techniques can be used for mining the Semantic Web itself. The second aim of this paper is to use these concepts to circumscribe what Web space is, what it represents and how it can be represented and analyzed. This is used to sketch the role that Semantic Web Mining and the software agents and human agents involved in it can play in the evolution of Web space.

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Ontic is an interactive system for developing and verifying mathematics. Ontic's verification mechanism is capable of automatically finding and applying information from a library containing hundreds of mathematical facts. Starting with only the axioms of Zermelo-Fraenkel set theory, the Ontic system has been used to build a data base of definitions and lemmas leading to a proof of the Stone representation theorem for Boolean lattices. The Ontic system has been used to explore issues in knowledge representation, automated deduction, and the automatic use of large data bases.

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In early stages of architectural design, as in other design domains, the language used is often very abstract. In architectural design, for example, architects and their clients use experiential terms such as "private" or "open" to describe spaces. If we are to build programs that can help designers during this early-stage design, we must give those programs the capability to deal with concepts on the level of such abstractions. The work reported in this thesis sought to do that, focusing on two key questions: How are abstract terms such as "private" and "open" translated into physical form? How might one build a tool to assist designers with this process? The Architect's Collaborator (TAC) was built to explore these issues. It is a design assistant that supports iterative design refinement, and that represents and reasons about how experiential qualities are manifested in physical form. Given a starting design and a set of design goals, TAC explores the space of possible designs in search of solutions that satisfy the goals. It employs a strategy we've called dependency-directed redesign: it evaluates a design with respect to a set of goals, then uses an explanation of the evaluation to guide proposal and refinement of repair suggestions; it then carries out the repair suggestions to create new designs. A series of experiments was run to study TAC's behavior. Issues of control structure, goal set size, goal order, and modification operator capabilities were explored. In addition, TAC's use as a design assistant was studied in an experiment using a house in the process of being redesigned. TAC's use as an analysis tool was studied in an experiment using Frank Lloyd Wright's Prairie houses.

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This paper describes a system for the computer understanding of English. The system answers questions, executes commands, and accepts information in normal English dialog. It uses semantic information and context to understand discourse and to disambiguate sentences. It combines a complete syntactic analysis of each sentence with a "heuristic understander" which uses different kinds of information about a sentence, other parts of the discourse, and general information about the world in deciding what the sentence means. It is based on the belief that a computer cannot deal reasonably with language unless it can "understand" the subject it is discussing. The program is given a detailed model of the knowledge needed by a simple robot having only a hand and an eye. We can give it instructions to manipulate toy objects, interrogate it about the scene, and give it information it will use in deduction. In addition to knowing the properties of toy objects, the program has a simple model of its own mentality. It can remember and discuss its plans and actions as well as carry them out. It enters into a dialog with a person, responding to English sentences with actions and English replies, and asking for clarification when its heuristic programs cannot understand a sentence through use of context and physical knowledge.

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We present a set of techniques that can be used to represent and detect shapes in images. Our methods revolve around a particular shape representation based on the description of objects using triangulated polygons. This representation is similar to the medial axis transform and has important properties from a computational perspective. The first problem we consider is the detection of non-rigid objects in images using deformable models. We present an efficient algorithm to solve this problem in a wide range of situations, and show examples in both natural and medical images. We also consider the problem of learning an accurate non-rigid shape model for a class of objects from examples. We show how to learn good models while constraining them to the form required by the detection algorithm. Finally, we consider the problem of low-level image segmentation and grouping. We describe a stochastic grammar that generates arbitrary triangulated polygons while capturing Gestalt principles of shape regularity. This grammar is used as a prior model over random shapes in a low level algorithm that detects objects in images.

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We present a novel scheme ("Categorical Basis Functions", CBF) for object class representation in the brain and contrast it to the "Chorus of Prototypes" scheme recently proposed by Edelman. The power and flexibility of CBF is demonstrated in two examples. CBF is then applied to investigate the phenomenon of Categorical Perception, in particular the finding by Bulthoff et al. (1998) of categorization of faces by gender without corresponding Categorical Perception. Here, CBF makes predictions that can be tested in a psychophysical experiment. Finally, experiments are suggested to further test CBF.

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The conceptual component of this work is about "reference surfaces'' which are the dual of reference frames often used for shape representation purposes. The theoretical component of this work involves the question of whether one can find a unique (and simple) mapping that aligns two arbitrary perspective views of an opaque textured quadric surface in 3D, given (i) few corresponding points in the two views, or (ii) the outline conic of the surface in one view (only) and few corresponding points in the two views. The practical component of this work is concerned with applying the theoretical results as tools for the task of achieving full correspondence between views of arbitrary objects.

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Tsunoda et al. (2001) recently studied the nature of object representation in monkey inferotemporal cortex using a combination of optical imaging and extracellular recordings. In particular, they examined IT neuron responses to complex natural objects and "simplified" versions thereof. In that study, in 42% of the cases, optical imaging revealed a decrease in the number of activation patches in IT as stimuli were "simplified". However, in 58% of the cases, "simplification" of the stimuli actually led to the appearance of additional activation patches in IT. Based on these results, the authors propose a scheme in which an object is represented by combinations of active and inactive columns coding for individual features. We examine the patterns of activation caused by the same stimuli as used by Tsunoda et al. in our model of object recognition in cortex (Riesenhuber 99). We find that object-tuned units can show a pattern of appearance and disappearance of features identical to the experiment. Thus, the data of Tsunoda et al. appear to be in quantitative agreement with a simple object-based representation in which an object's identity is coded by its similarities to reference objects. Moreover, the agreement of simulations and experiment suggests that the simplification procedure used by Tsunoda (2001) is not necessarily an accurate method to determine neuronal tuning.

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A fundamental question in visual neuroscience is how to represent image structure. The most common representational schemes rely on differential operators that compare adjacent image regions. While well-suited to encoding local relationships, such operators have significant drawbacks. Specifically, each filter's span is confounded with the size of its sub-fields, making it difficult to compare small regions across large distances. We find that such long-distance comparisons are more tolerant to common image transformations than purely local ones, suggesting they may provide a useful vocabulary for image encoding. . We introduce the "Dissociated Dipole," or "Sticks" operator, for encoding non-local image relationships. This operator de-couples filter span from sub-field size, enabling parametric movement between edge and region-based representation modes. We report on the perceptual plausibility of the operator, and the computational advantages of non-local encoding. Our results suggest that non-local encoding may be an effective scheme for representing image structure.

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The question of how shape is represented is of central interest to understanding visual processing in cortex. While tuning properties of the cells in early part of the ventral visual stream, thought to be responsible for object recognition in the primate, are comparatively well understood, several different theories have been proposed regarding tuning in higher visual areas, such as V4. We used the model of object recognition in cortex presented by Riesenhuber and Poggio (1999), where more complex shape tuning in higher layers is the result of combining afferent inputs tuned to simpler features, and compared the tuning properties of model units in intermediate layers to those of V4 neurons from the literature. In particular, we investigated the issue of shape representation in visual area V1 and V4 using oriented bars and various types of gratings (polar, hyperbolic, and Cartesian), as used in several physiology experiments. Our computational model was able to reproduce several physiological findings, such as the broadening distribution of the orientation bandwidths and the emergence of a bias toward non-Cartesian stimuli. Interestingly, the simulation results suggest that some V4 neurons receive input from afferents with spatially separated receptive fields, leading to experimentally testable predictions. However, the simulations also show that the stimulus set of Cartesian and non-Cartesian gratings is not sufficiently complex to probe shape tuning in higher areas, necessitating the use of more complex stimulus sets.

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Desarrollar un amplio marco conceptual por el que habrá que transitar para poder llegar a una definición de un modo personal de entender la atención a las Necesidades Educativas Especiales, que en cualquier caso deberá de ser flexible y abierto. Evolución del pensamiento sobre los problemas de las Necesidades Educativas Especiales en los distintos momentos que marcan la evolución histórica de esta dimensión de la educación. El trabajo se estructura en tres núcleos: 1) la Educación Especial en su evolución histórica y conceptual; 2) situación jurídica y legal de la Educación Especial en España; 3) aspectos didáctico-organizativos de la escolarización de los alumnos con Necesidades Educativas Especiales. Se realiza una breve revisión histórica sobre el concepto y el desarrollo de la Educación Especial y se analiza la situación actual de la misma en Europa Occidental y en América del Norte. Se definen algunos conceptos relacionados con normalidad y anormalidad: normalidad y patología, teorías y modelos explicativos de la deficiencia, terminología utilizada y consecuencias, rehabilitación y Necesidades Educativas Especiales. Con respecto a la situación jurídica de la Educación especial en España, se analiza su tratamiento en la Ley General de Educación de 1970, en la Constitución de 1978 y en la LOGSE. Se abordan también algunos aspectos que han de ser considerados desde un punto de vista didáctico y organizativo de la integración de los alumnos con Necesidades Educativas Especiales. Entre otros se habla de la dimensión socio-cultural de la deficiencia, el entorno de los procesos de integración, las funciones que debe cumplir la escuela (ser mecanismo de socialización y control y ser agente de innovación y cambio social), la necesidad de adaptación e individualización de los diseños curriculares, los criterios de escolarización a aplicar a estos niños, como implementar programas de aplicación individualizada, y metodología a aplicar. Se añade un anexo con las disposiciones legales vigentes que ordenan el tratamiento de las Necesidades Educativas Especiales.

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Estudiar y analizar la relaci??n entre la familia y la escuela en el nivel de educaci??n infantil, que son los dos primeros contextos en los que los ni??os se desenvuelven, y de ah?? su importancia. Fuentes documentales sobre la materia. Consta de dos partes, la primera orientada a analizar las bases te??ricas de la familia, su contextualizaci??n, el marco educativo de la instituci??n familiar y el marco legislativo de la relaci??n familia-escuela. Y la segunda parte se orienta al estudio de la relaci??n familia escuela en educaci??n infantil, su importancia, los problemas de la relaci??n, los niveles de participaci??n y las implicaciones educativas. Se termina con unas conclusiones generales deducidas de los diferentes cap??tulos de la investigaci??n. En el ??ltimo cap??tulo se enumeran estas conclusiones: el concepto de familia ha cambiado, la formaci??n de los distintos componentes de la familia resulta imprescindible para educar correctamente a los ni??os/as, es preciso investigar la tem??tica familiar, es evidente la importancia que tiene la relaci??n entre la familia y la escuela aunando criterios que repercuten positivamente en el alumnado, la etapa de la educaci??n infantil es la m??s id??nea para iniciar dichos contactos, no es suficiente tener una legislaci??n que contemple la importancia de las relaciones entre la familia y la escuela, sino que es necesario una sensibilizaci??n social y un gran esfuerzo por parte de ambos contextos, en nuestro pa??s no existe una tradici??n en la relaci??n familia centro, el centro escolar debe poner todos los medios a su alcance para facilitar los contactos entre ambos ??mbitos, es necesario establecer las v??as de participaci??n familia centro, tanto en el proyecto curricular del centro como en la programaci??n general anual, debiendo elegirse en cada momento las que m??s se ajusten a los objetivos espec??ficos.