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Latin America Transactions, IEEE (Revista IEEE America Latina)

Issue 1 • Date Jan. 2012

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Displaying Results 1 - 25 of 52
  • Table of Contents [includes the editorial to the special issue]

    Page(s): 1125 - 1134
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    Freely Available from IEEE
  • Admission Control for QoS Provision in Wireless Mesh Networks

    Page(s): 1135 - 1142
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    This work presents an admission control mechanism for multi-hop wireless mesh networks based on the IEEE 802.11e standard and the OLSR routing protocol. This mechanism, called CAC-OLSR, aims at ensuring that traffic flows with quality of service (QoS) requirements are only admitted in the mesh network if it has available resources in order to provide flow requirements. In addition, QoS requirements of previously admitted traffic flows cannot be violated. The proposal was evaluated with NS-2 simulations. View full abstract»

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  • An Improved Multiobjective Search Method Applied to Single Frequency Networks Planning

    Page(s): 1143 - 1148
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    This paper proposes a simpler and efficient approach to optimize digital television coverage and costs planning using a modified version of the well-known local search algorithm Hill Climbing. The results, taken from a real scenario in central Brazil, show the efficiency and applicability of the method by comparing results with other memetic strategies based on hybridation. View full abstract»

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  • Analyzing Real Time Communication Over FlexRay

    Page(s): 1149
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    In this paper we present an approach to timing analysis of applications communicating over a FlexRay bus, taking into consideration the specific aspects of the publish subscribe paradigm. We give an overview of works dealing with Data Distribution Service (DDS), scheduling over FlexRay and scheduling over the Control area Network (CAN). We are interesting in real time Quality of Service (QoS) for DDS. We specially focus on real time communication on static and dynamic FlexRay bus. We give our approach to calculate deadline on a DDS distribution using the equal Flexibility. We give also DDS and the task models for the computation. In Many distributed embedded real-time applications, like military, automobile, aeronautique data produced in one component of the system needs to be shared with other components of the system. The middleware Data Distribution Service DDS is divided into two components: the Data-Centric Publish-Subscribe DCPS layerand the Data local Reconstruction Layer DLRL. The DCPS layer transports data from publishers to subscribers according to Quality of Service QoS constraints associated with the data topic, publisher, and subscriber. The DLRL allows distributed data to be shared by local objects located remotely from each other as if the data is local. The DLRL is built on top of the DCPS layer. DDS impose of Service in transmission between publishers and subscribers. The transmission of data is managed by the real time bus. Real time applications use CAN or FlexRay bus. The challenge is to deal with a configuration using DDS middleware over FlexRay bus. The goal of using QoS in DDS is that all DataReaders read temporally valid data. DDS proveides QosPolicies specifically targeted to minimum latency, predictable real-time operation in high performance distributed data-critical systems. The DEADLINE QosPolicy expresses the maximum duration within which a DataReader expects a data-object instance to be updated. Our research team was interested in the- LifeSpan (LS) Qos which concerns the Topic and the Data Writer entities. It specifies the maximum duration of validity of the data written by the DataWriter. They developed [6] an algorithm that calculate data distribution deadline. The following assumptions are considered: all nodes, data objects, and scheduling parameters are known a priori; each DataReader/DataWriter has a local node, where it originates.; the period of a DataWriter is always less than its Lifespan; and the offered deadline period is always less then the requested deadline period. This work gives an analysis for deadline computation on a FlexRay bus. The goal is to consider the data-centric publish- subscribe (DCPS) and to use DDS Qos. Both Dynamic segment and static segment are considered. We are currently working on a project to implement deadline computation with C language in order to finalize our works dealing with our DDS implementation. View full abstract»

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  • Design of Automatic Meter Reading based on Zigbee

    Page(s): 1150 - 1155
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    This paper describes the study about Automatic Meter Reading (AMR) in indoor environments, implementing a WSN (Wireless Sensor Network) based on Zigbee technology. Automatic Meter Reading is used for remote collection of the utilities data. And these utilities may means electricity, gas, water consumption data or any other. Our concentration will be on Electricity power monitoring system which can monitor power quality, can remotely control power service which will enable prepaid billing. View full abstract»

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  • Introduction to the Software-defined Radio Approach

    Page(s): 1156 - 1161
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    Telecommunications have been in constant evolution during past decades. Among the technological innovations, the use of digital technologies is very relevant. Digital communication systems have proven their efficiency and brought a new element in the chain of signal transmitting and receiving, the digital processor. This device offers to new radio equipments the flexibility of a programmable system. Nowadays, the behavior of a communication system can be modified by simply changing its software. This gave rising to a new radio model called Software Defined Radio (or Software-Defined Radio - SDR). In this new model, one moves to the software the task to set radio behavior, leaving to hardware only the implementation of RF front-end. Thus, the radio is no longer static, defined by their circuits and becomes a dynamic element, which may change their operating characteristics, such as bandwidth, modulation, coding rate, even modified during runtime according to software configuration. This article aims to present the use of GNU Radio software, an open-source solution for SDR specific applications, as a tool for development configurable digital radio. View full abstract»

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  • Parking spaces detection in indoor environments based on Zigbee

    Page(s): 1162 - 1167
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    This paper describes the study about parking spaces detection in indoor environments, implementing a WSN (Wireless Sensor Network) based on Zigbee technology. Our study focuses on the analysis of the received power when a vehicle is parked or not, by monitoring the RSSI (Received Signal Strength Indicator) field defined in the MAC layer as the IEEE 802.15.4 describes. We focus in the analysis of three factors: data processing time, the influence of distance in received power and the attenuation effect in the signal when propagates, which determine the network topology to deploy and the validity of our location model. View full abstract»

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  • Performance Measurement Simulations for Analog-to-Digital Converters

    Page(s): 1168 - 1174
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    This paper concisely presents several common used techniques for measuring the dynamic performance of analog-to-digital conversion. Details about very critical tasks concerning spectral analysis are focused, showing examples to better justify the use of such techniques. It is shown how important is to precisely define the input frequency used for spectral analysis to enhance precision of results. This paper also proposes that the use of window deconvolution eases computation of the harmonics for performance analysis as compared with other commonly used techniques. The most relevant metrics applied for measuring performance are reviewed and demonstrated as a self-contained study. Simulation results are confronted with a commercial analog-to-digital converter. View full abstract»

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  • The Integration of the Satellite Communications with the Terrestrial Mobile Network (UMTS)

    Page(s): 1175 - 1179
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    Nowadays, the knowledge about the new technologies is indispensible for companies that depend on them to be developed as well as to keep ahead of the competitors. The main goal of this paper is to present an availability study that allows the integration of the Satellite Communications with the Terrestrial Mobile Network (UMTS), providing global roaming to the T-UMTS (Terrestrial Universal Mobile Telecommunications System) users. The accomplished simulation shows the availability of fragmenting the PDUs (Protocol Data Units) to improve the throughput in the satellite link. View full abstract»

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  • VHDL Implementation of a Flexible and Synthesizable FFT Processor

    Page(s): 1180 - 1183
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    This paper presents the current stage of development of a fast Fourier transform (FFT) processor in VHDL. This processor uses fixed-point as numeric representation, taking advantage of the facilities provided by the IEEE fixed point package. Its main advantages is that it is being developed as fully parameterizable processor, in a way that the number of bits, fixed point position and number of points computed in the FFT can be easily changed. It is also able to be used in several applications such as classification algorithms and communications systems. An open source prototype core has been developed and it can perform a complete FFT transform using radix-2 with decimation in time. Results and details of this implementation are presented. View full abstract»

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  • Video Quality Assessments on Digital TV and Video Streaming services using Objective Metrics

    Page(s): 1184 - 1189
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    There is a wide range of telecommunications services that transmit voice, video and data through complex transmission networks and in some cases, the service has not an acceptable quality level for the end user. In this sense the study of methods for assessing video quality and voice have a very important role. This paper presents a classification scheme, based on different criteria, of the methods and metrics that are being studied in recent years. This paper presents how the video quality is affected by degradation in the transmission channel in two kinds of services: Digital TV (ISDB-TB) due the fading in the air interface and video streaming service on an IP network due packet loss. For Digital TV tests was set up a scenario where the digital TV transmitter is connected to an RF channel emulator, where are inserted different fading models and at the end, the videos are saved in a mobile device. The tests of streaming video were performed in an isolated scenario of IP network, which are scheduled several network conditions, resulting in different qualities of video reception. The video quality assessment is performed using objective assessment methods: PSNR, SSIM and VQM. The results show how the losses in the transmission channel affects the quality of end-user experience on both services studied. View full abstract»

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  • VoIP Quality Enhancement with Wideband Extension Method in Broadband Networks

    Page(s): 1190 - 1194
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    Voice over Internet Protocol (VoIP) is one of the most important technologies in the world of communication. In this work, end-users connect via ADSL modem to broadband IP network and a variety of multimedia services utilized in this network. VoIP is the most important services in the broadband network and attempts focused on improving quality of voice in VoIP toward the quality of voice in PSTN. Perceived voice quality is an important function in VoIP applications. The main aim is to find an efficient speech enhancement method for perceptual optimization of voice quality. In this work, use bandwidth extension (BWE) method to estimate wideband envelope and improve quality and intelligibility. This method applies to some common codecs (e.g. G.711/ G.726/ G.729/ iLBC, speex) and then evaluates quality with ITU P.862.2 (wideband PESQ). Simulation takes under both low packet loss conditions and non packet loss conditions. The results illustrate that the BWE algorithm can achieve reliable perceived voice quality in comparison with the previous condition. View full abstract»

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  • Intrapreneur: An Emerging Setting in Business Economy

    Page(s): 1195 - 1200
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    This paper is an outcome from a literature research in databases of institutions' public libraries. It provides definitions about entrepreneurship, entrepreneurs, their characteristics and types. Corporate intrapreneurs or entrepreneurs are conceptualized and referenced and their characteristics are compared with those of traditional managers, entrepreneurs and intrapreneurs. It highlights the role of intrapreneurs in today's organizations, their contributions, bringing profitability through their actions, innovations, the change in organizational culture, as well as satisfaction and commitment. Intrapreneurs or corporate entrepreneurs are individuals who don't want to build and own a business, but work endeavoring internally in their jobs as if the companies were their and represent a new emerging configuration in business economics. Entrepreneurship to exist it is necessary to have people with entrepreneurial skills and develop employees, without the intrapreneurs there is no innovation in organizations. View full abstract»

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  • The nuclear energy power: challenges and innovations in medicine

    Page(s): 1201 - 1202
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    Nuclear Medicine is a medical area that uses a little quantity of radioactive material, added or not a medicine, with the objective to investigate and minimize/cure diseases. View full abstract»

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  • A Comparative Analysis of Accounting Software

    Page(s): 1203 - 1207
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    This work aims at analysing and comparing accounting softwares. Three out the principals current softwares used in the accounting enterprises are analysed. Among the obtained results, it is possible to indicate that Domínio Plus is the most used software; Radar is the most efficient; and Rubi the most specific for RH tasks. View full abstract»

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  • A Comparative Study On The Architecture Of Social Networks Facing Users Great Demand

    Page(s): 1208 - 1214
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    The social networking sites are places that allow people to share ideas, objectives and values. The challenge for social networking sites has been to keep its services available and functioning properly in order to serve its users and attract new ones. The objective of this research is to present a comparative study of the solutions found by Social Networks - Facebook, MySpace and Twitter - to investigate similarities or differences in the logical architecture of these systems. Such analysis is particularly relevant for those seeking more information on system architecture to meet a great demand of users. View full abstract»

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  • A DARP Based Approach for Implementation of Car Pooling Systems

    Page(s): 1215 - 1220
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    The increasing number of cars is an important issue for big cities administrations and several problems are related to this phenomenon, such as air pollution, traffic jams, drivers stress and so on. A potential solution for this problem is the use of car polling systems, which support the process of car sharing among users. However, current systems only work as a channel where providers and consumers can arrange shared cars for public transport. This work extends this idea via the use of DARP (Dial-a-Ride Problem) and metaheuristic concepts so that the allocation of rides can be carried out in an autonomous and dynamic way. The main aim of this approach is to optimize and facilitate the sharing process of personal cars, so that the number of vehicles in the roads can be reduced together with all the problems that such vehicles raise on. View full abstract»

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  • A New Change Detection Algorithm for Visual Surveillance System

    Page(s): 1221 - 1226
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    This paper describes the implementation of a background subtraction approach for indoor surveillance applications and presents a novel change detection algorithm. This algorithm uses a color similarity metric that considers the information of magnitude and phase of the difference between the background model and each video frame, both represented in the RGB color space. One of the advantages of such combination is that both features, magnitude and phase, take into account the intensity and the chromaticity information from a color image. The approach was tested using the PETS2004 database obtaining acceptable results. View full abstract»

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  • A Proposal for Reference Architecture for Personal Assistant Software Based on SOA

    Page(s): 1227 - 1234
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    Several efforts have been made towards creating personal assistant software (PAS) to help people in their daily life activities, at home or at work. In spite of the complexity PASs can have, most of the works focuses on developing solutions only for very specific tasks, without supporting integration and interoperation with other systems (including other PASs) and with enterprise systems and their respective business processes. Aiming at coping with these requirements, this work presents an open reference architecture for PASs, allowing that interoperable instances can be derived, personalized, implemented and deployed according to users' profiles and to enterprises' processes. An instance of a PAS has been derived and its results are discussed. View full abstract»

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  • A Semi-Automated Distributed Decision Support System Virutal Enterprises

    Page(s): 1235 - 1242
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    This paper presents a distributed collaborative decision support framework for problem resolution in partnerships of autonomous and heterogeneous enterprises. The developed prototype for conceptual model's verification and validations is composed by three important elements: a collaborative discussion tool via argumentation with moderation, flexible decision protocol and tools for previous impact of the decision by performance evaluation methods. View full abstract»

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  • A Systematic Mapping on the Role-Permission Relationship in Role Based Access Control Models

    Page(s): 1243 - 1250
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    Access control is a key component of security in any computer system. In the last two decades, the research on Role Based Access Control Models was intense. One of the most important components of a Role Based Model is the Role-Permission Relationship. In this paper, the technique of systematic mapping is used to identify, extract and analyze many approaches applied to establish the Role-Permission Relationship. The main goal of this mapping is pointing directions of significant research in the area of Role Based Access Control Models. View full abstract»

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  • Access control and collaborative authoring on the Semantic Web.

    Page(s): 1251 - 1255
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    Access control continues to be a major challenge in the information security area. Mechanisms such as OpenID and FOAF+SSL become necessary to supply decentralized authentication, to provide security and to assist in the management of users and their access to resources. Moreover, expectations of collaborative creation and editing still need support to promote Linked Data regardless of the application server. This article presents the mechanisms for decentralized access control and its application possibilities. Also featured are viable alternatives to implement collaborative creation and editing within the context of the Semantic Web. View full abstract»

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  • An Efficient Approach of Scheduling with Call Admission Control to Fixed WiMAX Networks

    Page(s): 1256 - 1264
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    The major challenge for the second decade of this century is the implementation of access to high-speed internet, known as broadband internet. Thus, the IEEE (Institute of Electrical and Electronics Engineers) has developed a new standard for wireless access, called IEEE 802.16. Also known as WiMAX (Worldwide Interoperability for Microwave Access), it is an emerging technology for next generation wireless networks which supports a large number of users, both mobile and nomadic (fixed), distributed across a wide geographic area. Based on these assumptions, and considering that the standard does not specify a scheduling algorithm, a new scheduler with call admission control was proposed based on Latency-Rate (LR) server theory and with system characteristics as specified by the system standard using the WirelessMAN-OFDM (Orthogonal Frequency Division Multiplexing) air interface. The proposed scheduler calculates the time frame (TF) in order to maximize the number of stations allocated in the system while managing the delay required for each user. Properties of this proposal have been investigated theoretically and through simulations. The results of simulations show that an upper bound on the delay can be achieved for a large range of network loads, with bandwidth optimization. View full abstract»

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  • An Overview of the Use of Metadata in Agriculture

    Page(s): 1265 - 1267
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    Metadata is data that fully describes the data and the areas they represent, allowing the user to decide on their use as best as possible. Allow reporting on the existence of a set of data linked to specific needs. The use of metadata has the purpose of documenting and organizing a structured organizational data in order to minimize duplication of efforts to locate them and to facilitate maintenance. It also provides the administration of large amounts of data, discovery, retrieval and editing features. The global use of metadata is regulated by a technical group or task force composed of several segments such as industries, universities and research firms. Agriculture in particular is a good example for the development of typical applications using metadata is the integration of systems and equipment, allowing the implementation of techniques used in precision agriculture, the integration of different computer systems via webservices or other type of solution requires the integration of structured data. The purpose of this paper is to present an overview of the standards of metadata areas consolidated as agricultural. View full abstract»

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  • Analysis and Performance of Traffic of Voice and Video in Network Indoor PLC

    Page(s): 1268 - 1273
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    With the development of PLC technology (Power Line Communication), which allows data transmission at high speed by the power grid. Emerged as a technology solution for last mile for transmission triple play. This article presents the analysis of VoIP and streaming videos in high definition through a residential indoor PLC network. 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