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Latin America Transactions, IEEE (Revista IEEE America Latina)

Issue 6 • Date Dec. 2012

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Displaying Results 1 - 19 of 19
  • Evaluation of a model for voice enhancement system of two channels

    Page(s): 2195 - 2200
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (664 KB)  

    A dual channel system for speech enhancement is proposed and evaluated under babbling noise. A two stage dual channel structure of adaptive filters is used with different microphones, one directional for receiving the desired signal and the other omni directional for receiving the ambient noise which for this model is mainly babbling. Simple Root Mean Square (RMS), Itakura-Saito Distance (ISD) and subjective evaluation tests are made in order to ease comparisons. Using a simple adaptive filter, it is not enough to reduce background noise while maintaining the intelligibility of enhanced speech. Therefore, a noise emphasizing channel is used in order to achieve a better noise canceling. This work is done as precedent for the implementation of a system capable of diminish the noise from voices different than the target by using adaptive filter structures offering good results but small enough to be embedded in hearing aid devices. View full abstract»

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  • Graph-reduction algorithm for finding shortest path in Geographic Information Systems

    Page(s): 2201 - 2208
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (666 KB)  

    Geographic Information Systems are computer systems that are used to store and manipulate information closely related to its geographical position. This technology has developed so rapidly in the past two decades that is already accepted as an essential tool for effective use of such information. An application of Geographic Information System is the shortest path search between two locations. The problem solved in this paper is to present a road network of a map (all objects) through a graph for subsequente network analysis, specifically for finding the shortest path and respond quickly to the users. We propose an algorithm for reducing a graph and an algorithm for searching shortest path in the reduced graph by the proposed algorithm. These results can be subsequently applied to Geographic Information Systems. View full abstract»

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  • Wheeled Mobile Robots: A review

    Page(s): 2209 - 2217
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (613 KB)  

    Robotics is a fast developing and exciting field with multiple applications which span from robot manipulators to mobile robots. This paper presents a literature review on wheeled mobile robots. We point out the main considerations to be taken into account when designing this class of robots. The main control problems are recalled as well as the corresponding solutions. Finally, we summarize the most important approaches used to render mobile robots autonomous. View full abstract»

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  • A hybrid algorithm for optimal placement of switches devices in electric distribution systems

    Page(s): 2218 - 2223
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (511 KB)  

    This paper presents a new formulation for tie switches and sectionalizers placement in distribution systems taking into consideration reliability and investments costs. The proposed algorithm uses six indexes defined by the distribution system data to apply a heuristic based on expert knowledge. A solution methodology based on fuzzy logic in conjunction with a genetic algorithm is proposed to determine the best sections for switches devices placement. The costs associated with installation of switch devices is calculated. Two real distribution feeders are used to evaluate the algorithm. The results show that the algorithm is efficient in selecting sections with high potential for switch allocation. View full abstract»

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  • Conflict Resolution Mechanism in the Electricity Sector Through the Experts Panel - The Chilean Case

    Page(s): 2224 - 2231
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (834 KB)  

    One of the main challenges facing the electricity sector worldwide is the design of efficient markets. In particular, the mechanisms used to solve regulatory conflicts are a crucial element of a regulatory regime and a major determinant of the risks borne by private investors. We use the case of the Chilean electricity sector to analyze the evolution of mechanisms for conflict resolution. We propose a conceptual framework based on bargaining theory that explains the behavior of market agents. This methodological approach describes the evolution of conflict resolution following the introduction of the Experts Panel in 2004, in particular, the reduction in the number of conflicts. This interpretation can be extended to other electricity markets in the region. View full abstract»

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  • Obtaining of better strategies for the frequency control in the electrical power system of Ecuador ( First Part )

    Page(s): 2232 - 2240
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (746 KB)  

    For the correct operation of the electric systems the frequency must remain around his nominal value's. The election of the frequency control strategies suitable in the electric systems is a task complicated by the great quantity of information demanded by the selection criteria . In the search of the better strategies the model of the system for different scenarios becomes essential. This work presents the better frequency control strategies on the base of the simulation of the behavior of the interconnected system Ecuador - Colombia. This paper is divided in two parts: the first part presents the model of the interconnected system Ecuador - Colombia and in the second part the better strategies of the frequency control will be developed. View full abstract»

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  • Unbalanced Three-Phase Induction Motors Starting and Arc Welding Machines Short-Circuit Modeling

    Page(s): 2241 - 2248
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (512 KB)  

    Three-Phase Induction Motors (TIM) and Arc Welding Machines (AWM) are loads of special behavior widely used in industrial and commercial installations, and therefore may contribute significantly to the deterioration of the quality of energy supplied by utilities. This paper proposes a modeling in constant power of the unbalanced TIM starting using Genetic Algorithm (GA) and AWM short-circuit based on their statics characteristics curves. The proposed models are compared with the conventional models in the literature. The results showed the good performance of the proposed models, allowing a more precise analysis of the real requests of these loads. View full abstract»

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  • A Graphical Modeling Language for Home Automation

    Page(s): 2249 - 2255
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (863 KB)  

    Home automation systems have emerged as one of the most attractive fields in engineering, thanks to the burgeoning demand from society for information systems. Today, the development of these systems is confined to the immediate context of the solution and is platform-dependent. This has intensified the need for suitable tools to tackle their development while enhancing quality and productivity. On one hand, domain specific languages allow the description of the system by means of graphic models easily and intuitively, using domain concepts. On the other hand, the model driven development approach stands out as a good option for solving the problems of the existing methods, as well as contributing tools that pioneer the development of domain specific languages. The present article proposes an alternative methodology and tools for the development of home automation applications following the model driven approach together with the use of a domain specific language. View full abstract»

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  • A Process Framework for the Software and Related Services Acquisition Based on the CMMI-ACQ and the MPS.BR Acquisition Guide

    Page(s): 2256 - 2262
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (814 KB)  

    The work presented in this paper has as main goal to define a process framework for software acquisition and related services, adherent to the recommendations and good practices of the existents models for process improvement: CMMI-ACQ and MPS.BR Acquisition Guide. In addition, the study also aims to provide the development of a free software tool to support the implementation and execution of the process framework defined and thus, making the tool also adherent to the models used as basis. Therefore, the paper presented seeks to provide an initial understanding of the project and discusses the steps taken during the project development, presenting the mapping results from comparing between models, followed by the framework description, resulted of mapping. Finally, we present some results obtained with the evaluation of the framework by experts. View full abstract»

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  • An Automatic Framework for Segmentation and Digital Inpainting of 2D Frontal Face Images

    Page(s): 2263 - 2272
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1336 KB)  

    Nowadays applications that use face images as input for people identification have been very common. In general, the input image must be preprocessed in order to fit some normalization and quality criteria. In this paper, we propose a computational framework composed of digital image quality computation, segmentation of the damaged regions on face images by statistical decision, morphological operators and image restoration by inpainting techniques. Additionally, in this work we propose a new method for digital inpainting that considers as relevant information for such restoration the neighboring pixel intensities as well as prior information extracted from an image database. To assess the efficiency of the computational framework proposed, we have used 2D face images from public databases. The results show that our inpainting method performs similarly to the traditional ones on quasi-homogeneous regions and gives better results when the damaged areas includes complex image patterns. View full abstract»

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  • CoolEdu - A Collaborative Multiagent Model for Decentralized Ubiquitous Education Environments

    Page(s): 2273 - 2279
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (652 KB)  

    The recent use of mobile devices and the widespread adoption of wireless computer networks have stimulated mobile and ubiquitous computing research. In this context, education is being considered one of the main application areas. The ability to accurately track the learner's position through a location system and the context awareness support allow the discovery of new pedagogical opportunities. Nowadays, there are several approaches to the organization of ubiquitous computing environments, even though the majority of them employ a centralized architecture. This approach brings some benefits, like easing the access to the learner profiles, but it also has some disadvantages intrinsic to the model, like scalability concerns and the physical separation between the learners and their profile data. This article proposes a collaboration model created for decentralized environments, capable of improving the learning process through the stimulus to the interaction between learners. This approach is modeled using agents, employing on a socio-interactionist model based on the "most capable pair" concept first introduced by Vygotsky. View full abstract»

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  • Genetic Algorithms Applied in Face Recognition

    Page(s): 2280 - 2285
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (559 KB)  

    Face recognition methods are computationally very expensive and use too much memory and processing time. An example of a method that allocates many computer resources is the Principal Component Analysis (PCA). In order to reduce processing time, was developed in this paper a method using only genetic algorithms to perform face recognition and comparison in the PCA method obtains higher accurate rates and less processing time. View full abstract»

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  • Table of Contents [includes the editorial to the issue]

    Page(s): 2286 - 2291
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    Freely Available from IEEE
  • Internet of Information and Services: A Conceptual Architecture for Integrating Services and Contents on the Future Internet

    Page(s): 2292 - 2300
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (759 KB)  

    Worldwide, dozens of projects to redesign the Internet are in progress under the banner of the so-called Future Internet research. Some proposals argue that the most important thing is to design to accommodate information exchanging, a.k.a. information-centrism. Others argue that the most important thing is to design to accommodate service-based applications. In this paper, we defend the idea that the most important thing is to design to integrate both aspects in a cohesive way. To do so, architectural blueprints should be able to solve indirections generally, to allow mobility and semantic rich search for services and contents, as well as location, hiring and dynamic invocation of services. In this paper, we propose a single conceptual architecture capable of integrating the service- and information-centric approaches for the Future Internet. We call this approach as Internet of Information and Services (IoIS). View full abstract»

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  • Model for designing Intelligent Tutorials Systems using Conceptual Maps and knowledge-based Systems

    Page(s): 2301 - 2308
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (767 KB)  

    Intelligent Tutorials Systems have demonstrated their effectiveness in various applications of the teaching-learning processes. However; its construction involves a complex and intense work of knowledge engineering, which prevents a more general use and optimal use. In this work provides a model that integrates the knowledge-based systems, the Conceptual Maps and Intelligent Tutorials Systems that favors the design of these systems, taking into account the facilities and naturalness of the Conceptual Maps. The proposed model is the basis for the design and implementation of HEMCI computational tool, which is under development, and promotes the development of Intelligent Tutoring Systems to computer non-expert users. Finally, an example of the model described for the teaching-learning process of the basic theory of combinational logic approach. View full abstract»

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  • Proposal and Evaluation of Load-Dependent Distributed Scheduling Algorithm for WiMAX in Mesh Mode

    Page(s): 2309 - 2315
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (622 KB)  

    The IEEE 802.16 standard defines a broadband access network technology called WiMAX, that besides the point-to-multipoint mode it also defines a mesh mode. In this paper we propose a modification of scheduling defined in the standard for the mesh mode to incorporate dependence on the node's load. The performance of the load-dependent distributed scheduling is compared with the distributed scheduling and the centralized scheduling of the standard, using NS-2 simulator with a modified WiMAX module. According to the simulations results, the load-dependent distributed scheduling algorithm outperformed the standard distributed algorithm in terms of the evaluated metrics. View full abstract»

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  • Supporting Virtual Meetings in Distributed Scrum Teams

    Page(s): 2316 - 2323
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (826 KB)  

    Scrum has gained surprising momentum as an agile project management approach. It provides effective social integration by building up social team capital, and it provides much needed control and coordination mechanisms. Especially, daily Scrum meetings ensure an open channel for communication. However, this channel has been threatened by distributed software development which has highly been adopted in software industries. To support virtual meetings regardless physical locations of team members, we developed a 3D tool based on Scrum life cycle. The tool provides a virtual world consisted in technology to hold meetings in a Scrum context. We used a questionnaire to evaluate the usability and effectiveness of the tool with undergraduate students. View full abstract»

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  • Thermal insulation in houses and sheds

    Page(s): 2324 - 2330
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (645 KB)  

    The optimized design of thermal insulations of residential houses and industrial buildings is increasingly required in order to save energy and reduce maintenance cost. However, quality standards in the construction business in Latin America usually do not include user-friendly optimization methods to assess the best insulation in each region. In general, users do not have technical background and end up solving thermal problems using heating and air conditioning systems. Moreover, most people do not know how to reduce energy costs and spend large amounts of money because they believe that is the price to pay for comfort. In this paper a computational tool to analyze the influence of thermal insulation on heat transfer through the roof of buildings is presented. The application displays the advantages of installing different thermal insulation in different weather conditions in various regions of Argentina, and provides comparative figures to assist cost optimizations. View full abstract»

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  • When and How to use the online configurator in the Automobile Industry

    Page(s): 2331 - 2341
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (649 KB)  

    In the Mass Customization (CM), the product configurator helps the customers to identify their individual needs and assists to transform these needs into a customized product. The objective of this paper is to verify relation between online configurators and their features with business variables of automobile companies. The sample consists of 134 automobile companies located in 31 different countries corresponding to 38.83% of the worldwide car production in 2008. The logistic regression (logit) confirmed the relation between online configurators and their features with the business variables. It also identifies the online configuration's set of features correlating with an increase in the sale of vehicles. View full abstract»

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Aims & Scope

IEEE Region 9 provides IEEE Latin America Transactions to enable the publication of non-published and technically excellent papers from Latin American engineers, in Spanish or Portuguese languages.

Full Aims & Scope

Meet Our Editors

Editor-in-Chief
José Antonio Jardini (Brasil)
IEEE Fellow Member