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Latin America Transactions, IEEE (Revista IEEE America Latina)

Issue 3 • Date June 2010

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Displaying Results 1 - 15 of 15
  • Closed Loop Identification Using Takagi Sugeno Models

    Page(s): 199 - 204
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (484 KB)  

    The continuous advances in systems theory have been based on precise process models, experimental models who includes the information of actuators, sensors, uncertainties and nonlinearities. The study presented as follows is focused on the development of a technique for closed loop identification using Youla Parametrization combined with Neuro Fuzzy nets. The proposed methodology have been evaluated over SISO and MIMO plants achieving great precision on the different cases where is tested, resulting on an excellent option for process models construction for development of new theories in control design. View full abstract»

    Open Access
  • Handoff Traffic Acceptance Criteria with QoS Guarantee for the CDMA 1xEV-DO RA System

    Page(s): 205 - 213
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (568 KB)  

    In this article two new criteria for handoff traffic acceptance based on the received signal power and the buffer occupation percentage are proposed. The proposed criteria are evaluated in conjunction with the data schedulers Max C/I (Maximum Carrier Interference) and PF (Proportional Fair). The evaluation is carried out through HTTP source models and using QoS metrics such as the average packet delay, the throughput and the loss percentage in function of handoff traffic load. The results showed that depending on the chosen criterion, it is possible to assure the QoS of CDMA 1xEV-DO RA system and still to accept a good amount of handoff traffic. View full abstract»

    Open Access
  • Hybrid Algorithms for Routing and Assignment Wavelengths in Optical Networks

    Page(s): 214 - 220
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (639 KB)  

    This paper presents a strategy for the solution of the WDM optical networks planning. Specifically, the problem of Routing and Wavelength Allocation (RWA) in order to minimize the amount of wavelengths used. In this case, the problem is known as the Min-RWA. Two meta-heuristics (Tabu Search and Simulated Annealing) are applied to take solutions of good quality and high performance. The key point is the degradation of the maximum load on the virtual links in favor of minimization of number of wavelengths used; the objective is to find a good compromise between the metrics of virtual topology (load in Gb/s) and of the physical topology (quantity of wavelengths). The simulations suggest good results when compared to some existing in the literature. View full abstract»

    Open Access
  • A Model for Bundled Conductors Considering a Non-Homogeneous Distribution of the Current through Subconductors

    Page(s): 221 - 228
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (595 KB)  

    This paper describes an alternative procedure to obtain an equivalent conductor from a bundled conductor, taking into account the distribution of the current in subcondutors of the bundle. Firstly, it is introduced a brief background about the concept of Geometric Mean Radius (GMR) and how this methodology is applied to define an equivalent conductor and its electric parameters. Emphasizing that the classical procedure, using GMR, is limited to premise which the current is equally distributed through subconductors. Afterwards, it is described the development of proposed method and applications for an equivalent conductor obtained from a conventional transmission line bundled conductor and from an equivalent conductor based on a bundle with compressed SF6 insulation system, where the current is unequally distributed through subconductors. View full abstract»

    Open Access
  • Luminance Optimization in Closed Environments by Simulated Annealing

    Page(s): 229 - 235
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (622 KB)  

    This work presents a novel automated method for optimization of luminaries distribution in closed environments using a simulated annealing method. The input variables of the optimization method are: luminance level, luminance uniformity, installation cost and operational cost. In addition to the development of an automated method, this work offers a graphic tool to improve the environment data input and to present the results of the luminance project. To develop an optimized project, the method requires the following information: luminary type, environment destination, environment blueprint and reflection wall conditions. In the results, we show the method's performance changing the simulated annealing method parameters such as initial temperature, temperature decrease rate and number of iterations at the same temperature. We also compare the results of the developed method with results presented by the lumen method and with a project developed by a specialist. In conclusion, the use of a simulated annealing optimization method for this luminance project facilitates developing an efficient tool optimizing all the parameters previously mentioned. View full abstract»

    Open Access
  • Multi Objective Evolutionary Algorithm Applied to the Optimal Power Flow Problem

    Page(s): 236 - 244
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (711 KB)  

    This work presents the application of a multiobjective evolutionary algorithm (MOEA) for optimal power flow (OPF) solution. The OPF is modeled as a constrained nonlinear optimization problem, non-convex of large-scale, with continuous and discrete variables. The violated inequality constraints are treated as objective function of the problem. This strategy allows attending the physical and operational restrictions without compromise the quality of the found solutions. The developed MOEA is based on the theory of Pareto and employs a diversity-preserving mechanism to overcome the premature convergence of algorithm and local optimal solutions. Fuzzy set theory is employed to extract the best compromises of the Pareto set. Results for the IEEE-30, RTS-96 and IEEE-354 test systems are presents to validate the efficiency of proposed model and solution technique. View full abstract»

    Open Access
  • Transmission of Electric Energy: a Bibliographic Review

    Page(s): 245 - 258
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (704 KB)  

    The reforms carried out in various energy markets assign a central place to the transmission and hence this has created a dynamic research area, which is reported in this paper. There are various research topics, so it is required to identify the different areas and scientific advances in the field. Setting the types of assumptions used in the models and the influence of dynamic variables such as generation, demand and flow control will allow a better understanding of market dynamics. A comprehensive literature review is performed and in a context of power markets the most recent and relevant research in the evolution of the transmission is assessed. The paper presents topics of economic regulation and market mechanisms, planning, financial assessment, assignment, network congestion, economic and technical modeling methods and the influence of transmission technologies in the energy market. Research has sought to provide coupling mechanisms between economic and technical concepts, in order to provide feasible solutions to the electricity market. The debate about which is the best mechanism for the regulation of transmission, the planning model and the allocation of transmission costs, are still in force. The new contributions are focused on the impact of transmission on the market and the social benefits of the proposed mechanisms for transmission expansion. View full abstract»

    Open Access
  • A Formal Model for the Requirements Diagrams of SysML

    Page(s): 259 - 268
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (524 KB)  

    There are several notations to build a model: textual, graphical and by using mathematics. The Object Management Group (OMG) has developed a graphical notation to model systems called SysML (system modeling language); this notation includes the modeling of the system requirements. In this paper a precise model of the requirements diagrams of SysML is presented. This model is made using a modeling language called Alloy, which has been used to formally specify UML diagrams. View full abstract»

    Open Access
  • A Study of the Compartimentalized Knapsack Problem with Additional Restrictions

    Page(s): 269 - 274
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (582 KB)  

    The Compartimentalized Knapsack Problem has been reported in the literature to generate cutting patterns of problems in two stages. The problem has constrained case, which are considered limits on the number of compartments and items in the knapsack. An exact algorithm that involves the resolution of various knapsacks and heuristics based on upper bound has already been developed. In this paper we present the problem with mathematical models and propose new strategies for resolving the constrained case. View full abstract»

    Open Access
  • Application of Bayesian Networks to Assist the Expansion of the Digital Inclusion of Elderly People

    Page(s): 275 - 279
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (481 KB)  

    This article presents the construction of a bayesian network as a tool to assist an initiative of elderly digital inclusion, accomplished at the Federal University of Santa Catarina, in their nucleus of studies for people of third age that participate in computer science classes in a homogeneous group as for the age group. Detected the need to form people to aid in those classes, students of the own group, denominated multipliers, were identified previously with appropriate profile for the function. That previous identification of elderly knowledge multipliers was accomplished with the aid of a bayesian network, which identifies the characteristics of that profile in the initial moment of the classes. View full abstract»

    Open Access
  • Conflicts in AspectJ: Restrictions and Solutions

    Page(s): 280 - 286
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (643 KB)  

    A conflict among aspects happens when two or more aspects compete for its activation. The treatment of conflicts should provide mechanisms for the detection and resolution of the same ones, with the objective of avoiding that the software execution will be uncertain and unstable. However, the mechanisms provided by the programming aspect-oriented tools can be really limited, being this the case of AspectJ. In consequence, the resolution of certain conflicts becomes a critical problem since it drives to the restructuring of the code of the aspects. In this work the conflicting situations are identified that they are critical in AspectJ and particular and general solutions are delineated to the problem. View full abstract»

    Open Access
  • Creational Object-Oriented Design Pattern Applied to the Development of Software Tools for Electric Power Systems Dynamic Simulations

    Page(s): 287 - 295
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (684 KB)  

    The development of software for dynamic simulation of electrical power systems requires a comprehensive range of complex studies, which encompasses many areas of electrical engineering as well as software engineering. This study aims at to develop an efficient strategy applied to the development of software tools for dynamic power systems simulations studies. The proposed strategy is based on the object-oriented creational pattern. This approach has the advantage of makes easy the application development process, by performing a mapping between block diagram model representation and the corresponding specialized classes. Firstly, a conceptual mapping between block diagram and the object-oriented paradigm, based on the Factory Method, is carried out. After that, some flexible strategies are presented in order to obtain an improved efficiency for the numerical routines, based on the Builder standard. This allows for the parameterization of the selected numerical integration techniques. The proposed strategy was evaluated by using a 4-generator multi-machine power system. The simulation results shown that the proposed strategy was able to provides a good power system dynamic performance. View full abstract»

    Open Access
  • Development of Method for Research in Natural Language of Software Components

    Page(s): 296 - 303
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (583 KB)  

    A library of software components exerts an important role in corporative level, supporting the documentation, specification, storage and recovery of components. This work considers the storage and the recovery of software components with the use of an interface in natural language. A method to generate a representation form is described, to be stored in the library, for the texts that describe the characteristics of the components that live in the library. The text of the consult generated by the user is also represented the same way in order to allow the comparison between the descriptions of the components of the library and the user question. Additionally the method allowed to determine the similarity between parts of the representations of the text of the characteristics with the text of the consult, returning as resulted the components that better take care of the user question in order decreasing of priority. View full abstract»

    Open Access
  • Digital Video Watermarking in DWT Domain Using Chaotic Mixtures

    Page(s): 304 - 310
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (964 KB)  

    This paper presents a public video watermarking algorithm, whose robustness depends on the embedding energy, which must be limited due to the degradation of video sequence caused by the same watermark signal. The proposed algorithm embeds a perceptually recognizable binary pattern, such as owner's logotype. Firstly the video sequences are segmented by each scene, and then the binary watermark pattern is embedded into Discrete Wavelet Transform (DWT) domain of the randomly selected scene blocks. To increase the security of the proposed scheme, the biary watermark pattern is mapped to a noise like binary pattern using a chaotic mixing method, before its embedding. Simulation results show the watermark imperceptibility and robustness against several attacks, such as noise contamination, frame dropping, frame averaging and frame swapping; the evaluation results also show that the extracted watermark pattern is sufficiently clear, although the watermarked video sequence may suffered several attacks. View full abstract»

    Open Access
  • Extraction of Execution Patterns in Multi-Agent Systems

    Page(s): 311 - 317
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (617 KB)  

    Multi-agent executions become a difficult to follow task when there are lots of agents working concurrently. Programmers need to know if the system is working according to their expectations. In such situations, debugging tools are useful to follow the execution traces, but are not enough for such complex systems. An alternative solution is to save the execution traces (logs) in data warehouses, where they will be analysed through data mining techniques and queries. These techniques offer the programmer a summary of the execution parameters and even the discovery of unexpected patterns. View full abstract»

    Open Access

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.

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Meet Our Editors

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