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Editorial (p. 3), Gerardo Sierra

SPECIAL SECTION: Natural Language Processing

Natural Language Syntax Description using Generative Dependency Grammar (pp. 5-18)

The paper presents a practical solution to describe natural language syntax. This solution is based on a Generative Dependency Grammar (GDG). A theoretical definition of these grammars and some of their proprieties is given. GDG are implemented in a declarative computer language GRAALAN (Grammar Abstract Language). The paper shortly present the features of GRAALAN and, after that, a more detailed implementation of natural language syntax description is given. GRAALAN offers for natural language syntactic description some strong features that respond to the following requests: a compact description, the possibility to express the syntax and the agreement and to specify the errors met in a text. The description has also the feature of reversibility. The paper presents some conclusions concerning the using of GRAALAN to describe the syntax (among others natural language features).

Modeling a Quite Different Machine Translation using Lexical Conceptual Structure (pp. 27-31)

The goal of this study is to outline the readability of an Example-Based Machine Translation for any pair of languages by means of the language-independent properties of the lexical conceptual structure (LCS). We describe LCS as a representation of traditional dependency relationships and use in experiments an isolated pair of verbs, extracted from Orwell’s “1984” parallel English – Romanian texts. We discuss the mental models in terms of specific knowledge structures. Finally, we present LCS-Based Machine Translation from the point of view of a complex adaptive system and present our ongoing work in order to capture the neutral linguistic core of any mental model corresponding to the real world.

Named Entity Recognition in Hindi using Maximum Entropy and Transliteration (pp. 33-41)

Named entities are perhaps the most important indexing element in text for most of the information extraction and mining tasks. Construction of a Named Entity Recognition (NER) system becomes challenging if proper resources are not available. Gazetteer lists are often used for the development of NER systems. In many resource-poor languages gazetteer lists of proper size are not available, but sometimes relevant lists are available in English. Proper transliteration makes the English lists useful in the NER tasks for such languages. In this paper, we have described a Maximum Entropy based NER system for Hindi. We have explored different features applicable for the Hindi NER task. We have incorporated some gazetteer lists in the system to increase the performance of the system. These lists are collected from the web and are in English. To make these English lists useful in the Hindi NER task, we have proposed a two-phase transliteration methodology. A considerable amount of performance improvement is observed after using the transliteration based gazetteer lists in the system. The proposed transliteration based gazetteer preparation methodology is also applicable for other languages. Apart from Hindi, we have applied the transliteration approach in Bengali NER task and also achieved performance improvement.

REGULAR PAPERS

Visualización 3D de Deformación y Corte de Objetos Virtuales basada en Descomposición Ortogonal (pp. 43-47)

Se muestra la implementación gráfica de un nuevo modelo para la renderización de fuerzas de contacto durante la interacción háptica dentro de ambientes virtuales 3D para  deformación y corte de objetos virtuales con propiedades dinámicas y superficiales complejas. Se define un algoritmo simple para la triangulación de un objeto virtual, empleando algoritmos clásicos para la detección de colisiones. Se desarrolló un algoritmo para la visualización del corte de la malla triangular así como para el cálculo de las dinámicas de la malla durante el corte. Se presentan imágenes de la plataforma utilizando OpenGL y Visual C++, para la parte gráfica y el dispositivo Falcon para la retroalimentación háptica.

3D Visualization of Deformation and Cut of Virtual Objects based on Orthogonal Decomposition

We present graphic implementation of a novel model for contact force rendering during the haptic interaction in 3D virtual environment. It is applied during cut and deformation of virtual objects with complex dynamic and surface properties. We define the simple algorithm for triangulation of the virtual object using the classic algorithm of detection of collisions. The algorithm is proposed that allows visualizing of the cutting triangular net as well as the calculation of the dynamics of the net during the cut. We present the corresponding images using OpenGL and Visual C++ for the graphic module and Falcon device for haptic feedback.

An Extended Video Database Model for Supporting Finer-Grained Multi-Policy and Multi-Level Access Controls (pp. 49-62)

The growing amount of multimedia data available to the average user has reached a critical phase, where methods for indexing, searching, and efficient retrieval are needed to manage the information overload. Many research works related to this field have been conducted within the last few decades and consequently, some video database models have been proposed. Most of the modern video database models make use of hierarchical structures to organize huge amount of videos to support video retrieval efficiently. Even now, among open research issues, video database access control is still an interesting research area with many proposed models. In this paper, we present a hybrid video database model which is a combination of the hierarchical video database model and annotations. In particular, we extend the original hierarchical indexing mechanism to add frames and salient objects at the lowest granularity level in the video tree with the aim to support multi-level access control. Also, we give users more solutions to query for videos based on the video contents using annotations. In addition, we also suggest the original database access control model to fit the characteristics of video data. Our modified model supports both multiple access control policies, meaning that a user may be affected by multiple polices, and multi-level access control, meaning that an authorization may be specified at any video level. Theoretical analyses and experimental results with real datasets are presented that confirm the correctness and efficiency of our approach.

Multiplicador Electrónico para Encoder Incremental (pp. 63-67)

Se presenta el diseño y simulación de un multiplicador electrónico para encoders incrementales, el sistema consiste en un decodificador que extrae el total de la información contenida en la señal de cuadratura, esta  información da referencia para resoluciones en  1x, 2x y 4x. Este multiplicador tiene como propósito elevar la resolución de la señal de retroalimentación, empleando el mismo encoder. Se diseña totalmente con circuitos digitales para su implementación en lógica reconfigurable.

Electronic Multiplicator for Incremental Encoder

We present design and experiments on simulation of the electronic multiplicator for incremental encoders. The system consists in a decoder that extracts the total information contained in the quadrature signal. This information is used as reference for 1x, 2x and 4x resolutions. The purpose of the multiplicator is to increment the resolution of the feed back signal using the same encoder. It is designed completely in digital circuits for its implementation in the reconfigurable devices.

Distance Online Learning and Evaluation Framework (pp. 69-74)

In this paper, the authors present the concept of a system for Distance Object Learning and Evaluation (DOLE), which can be used during the teaching-learning process as a virtual learning environment. The term Distance Object Learning is used here for learning over a computer network or the Internet about real world entities that are distinguishable from others. The DOLE system concept uses standards for Learning Object Metadata (LOM) at different levels of abstraction. The objective of the resulting system is not only the correct and retrievable description of the course material covered by the LOM but also the further use of parts of the LOM data set for the generation of learning materials and students' learning development assessment, which can be represented by quizzes and tests. The Distance Object Learning and Evaluation system concept outlined in this paper is based in part on an earlier version of an E-learning Assessment System for Young learners (EASY). DOLE extends the concept of EASY by a learning component and by posing system generated questions with the help of a forward-chaining inference engine to find out about a specific item (object) of the domain of instruction. As the questioning process is bidirectional ("open" questions can be asked by the system as well as by the learner), DOLE is more targeted at advanced and adult learners than at young learners. The ultimate goal is to use the DOLE system concept as a part of a virtual college or university.

Computadoras de Bolsillo como una Alternativa para el Control de Servomotores en Robótica (pp. 75-79)

Este trabajo muestra el diseño de un sistema básico de control para servomotores convencionales, implementado en una computadora de bolsillo. La particularidad de esta realización radica en la interfaz hardware conformada por un microcontrolador que conecta al respectivo servomotor con el PDA a través del puerto serie de éste último. El sistema es de propósito general y se puede adaptar sin cambios drásticos a cualquier aplicación similar.

PDA Computers as an Alternative for Servo Motors Control in Robotics

This paper presents a system that allows for control of conventional servo motors using PDA computers. The advantage of the proposed implementation is related to hardware interface, namely, to the usage of the specialized microcontroller that connects PDA with the servo motor using serial port of the PDA. The system can be easily adapted to other similar applications.

Diseño de un Coprocesador Matemático de Precisión Simple usando el Spartan 3E (pp. 81-89)

Una Unidad de Punto Flotante (Floating Point Unit en inglés) o, más comúnmente conocido como, coprocesador matemático y es un componente de la CPU especializado en las operaciones de punto flotante. Las operaciones básicas que toda FPU puede realizar son las aritméticas (suma y multiplicación), si bien algunos sistemas más complejos son capaces también de realizar cálculos trigonométricos o exponenciales. No todas las CPUs tienen una FPU dedicada. En ausencia de FPU, la CPU puede utilizar programas en microcódigo para emular una función en punto flotante  a través de la unidad aritmético-lógica (ALU), la cual reduce el costo del hardware a cambio de una sensible pérdida de velocidad. El objetivo de  este articulo, es mostrar como puede ser implementado un coprocesador matemático  utilizando VHDL, para su implementación en cualquier FPGA.

Design of Mathematical Coprocessor of Simple Precision using Spartan 3E

Floating Point Unit (FPU) is also known as mathematical coprocessor and is a specialized component of the CPU dedicated to floating point operations. Basic operations of any FPU are arithmetic (sum and multiplication), though some more complex systems are also able to perform trigonometric or exponential calculations. Not all CPUs have an additional FPU. If there is no FPU present, then CPU can use some programs written in microcode for emulation of floating point operations using arithmetic-logical unit (ALU). This reduces the cost of the hardware but slow down the processing speed. The purpose of this paper is to propose an implementation of the mathematical coprocessor using VHDL, for its further implementation in FPGA.