Villagarcía Wanza, Horacio A.
In the first paragraph of the Introduction of the book the authors say "The definition of computer architecture has generated many discussions since the emergence of what could be considered the first computer in 1943, the ENIAC". Later they add "The main idea of all the proposals made in this direction is the same: define of computer components in different levels of study to produce a hierarchical description and to facilitate their understanding and design”. The authors' goal is to provide a textbook (written in Spanish) that systematically collect the most important techniques of design and evaluation of computer architectures.
López, Ricardo A.
The microcontrollers are embedded in our way of life and are found in many devices. The ability of Very High Scale Integration (VLSI) - with almost exponential growth in recent years makes these devices every day contain functions previously unthinkable.
Therefore, a grouping of these networked devices creates a very powerful system, which equipped with a standard protocol that allows interconnection to the Internet gives you a virtually unlimited range of scalability. For these reasons, this thesis studied the implementation of a network of microcontrollers, defining functions equivalent to those with Supervisory Control and Data Acquisition (SCADA) of great scale. Based...
Lanzarini, Laura Cristina; Villa Monte, Augusto; Estrebou, César Armando
E-mail texts are hard to process due to their short length. In this article, the use of a diffuse neural network that is capable of identifying the most relevant terms in a set of e-mails is proposed. The associations between these terms will be measured through association rules built with the terms identified by the network. The metrics support, confidence and interest of the rules will be used to qualify the corresponding terms. The method proposed has been used to process e-mails of the PACENI Project (Support Project for Improving First-Year Teaching in Courses of Studies in Exact and Natural...
Luo, Xu-Ren; Yin, Te-Lung
In this paper, we present a new reversible data hiding scheme that utilizes the wavelet transform and better exploits the large wavelet coefficient variance to achieve high capacity and imperceptible embedding. Our scheme differs from those of previous studies in that the wavelet coefficients histogram rather than the gray-level histogram is manipulated. In addition, we design intelligent histogram-shifting rules to avoid the decimal problem in grayscale pixel values after recovery process to achieve reversibility. Small changes in the wavelet coefficients after embedding process are important factors contributing to low visual distortion in the marked image. Furthermore, an important property of...
Cenci, Karina M.; Ardenghi, Jorge Raúl
We propose a distributed solution for the group mutual exclusion problem based on priorities, in a network with no share memory whose members only communicate by messages. The proposed algorithm is composed by two players: groups and processes, groups are passive players while processes are active players. For the coordination access to the resource, each group has assigned a quorum. The groups have associated a base priority in each stage, meanwhile the processes have the same level priority. An important feature is that processes have associated a time to participate in the group in each stage. The message complexity obtain,...
Leiva, Lucas; Acosta, Nelson
This paper presents a parallel architecture for a radial basis function (RBF) neural network used for pattern recognition. This architecture allows defining sub-networks which can be activated sequentially. It can be used as a fruitful classification mechanism in many application fields. Several implementations of the network on a Xilinx FPGA Virtex 4-(xc4vsx25) are presented, with speed and area evaluation metrics. Some network improvements have been achieved by segmenting the critical path. The results expressed in terms of speed and area are satisfactory and have been applied to pattern recognition problems.
Akhtar, Nasim; Rashid, Mamunur; Islam, Shafiqul; Kashem, Mohammod Abul; Kolybanov, Cyrll Y.
Data compression offers an attractive approach to reducing communication cost by using available bandwidth effectively. It also secures data during transmission for its encoded form. In this paper an index based position oriented lossless text compression called PIPC ( Position Index Preserving Compression) is developed. In PIPC the position of the input word is denoted by ASCII code. The basic philosopy of the secure compression is to preprocess the text and transform it into some intermediate file which can be compressed with better efficiency and which exploits the natural redundancy of the languaje in making the transformation. The proposed algorithm...
When IBM's John Backus first developed the Fortran programming language, back in 1957, he certainly never dreamt that it would become a world-wide success and still be going strong many years later. Given the oft-repeated predictions of its imminent demise, starting around 1968, it is a surprise, even to some of its most devoted users, that this much-maligned language is not only still with us, but is being further developed for the demanding applications of the future. What has made this programming language succeed where most slip into oblivion? One reason is certainly that the language has been regularly standardized....
Almeida Martins, Nardênio; El'youssef, Ebrahim Samer; De Pieri, Edson Roberto; Lombardi, Warody Claudinei; Jungers, Marc
In this paper, a trajectory tracking control for a nonholonomic mobile robot subjected to uncertainties and disturbances in the kinematic model is proposed. An adaptive variable structure controller based on the sliding mode theory is used, and applied to compensate these uncertainties and disturbances. To minimize the problems found in practical implementation using classical variable structure controllers, and eliminate the chattering phenomenon as well as compensate disturbances a neural compensator is used, which is nonlinear and continuous, in lieu of the discontinuous portion of the control signals present in classical forms. The proposed neural compensator is designed by a modeling...