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Latin America Transactions, IEEE (Revista IEEE America Latina)

Issue 3 • Date April 2012

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Displaying Results 1 - 25 of 26
  • Table of Contents [includes the editorial to the special issue]

    Publication Year: 2012 , Page(s): 1667 - 1679
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    Freely Available from IEEE
  • A New Aspect of Walsh-Hadamard Coding over Rayleigh Fading Channels

    Publication Year: 2012 , Page(s): 1680 - 1685
    Cited by:  Papers (1)
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    This paper analyzes the performance of Walsh-Hadamard coded modulation schemes that arise by traditional spreading and multiplexing of antipodal information bits with standard Walsh-Hadamard matrices, over fully interleaved flat Rayleigh fading channels. The resulting Pulse Amplitude Modulation (PAM) constellations are processed by an optimum Maximum A posteriori Probability (MAP) vector detector at the receiver, including external diversity combining. Tight upper and lower bounds are derived for the mean bit error probability, verified by extensive Monte Carlo simulations. The results show that the exploited inherent time diversity of the coded modulation scheme provides substantial gains over standard BPSK modulation for fully interleaved Rayleigh fading channels, without any bit rate reduction (for rate 1 codes) or mean symbol energy increase. The performance is enhanced by increasing the size of the Walsh-Hadamard matrices with the drawback of increased detection complexity and higher instant power variations. View full abstract»

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  • Controlling Physical Objects via the Internet using the Arduino Platform over 802.15.4 Networks

    Publication Year: 2012 , Page(s): 1686 - 1689
    Cited by:  Papers (1)
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    In this work, we expanded the Arduino's capabilities by adding an 802.15.4 wireless module, in order to expose its functionality as a Web of Things node. The second contribution of our work is a careful description of the necessary steps to make a heterogeneous network interoperate and the implementation of a network stack for the 4 most representative hardware platforms, as used by the relevant research community (Arduino, SunSPOT, TelosB, iSense), in the form of a software library, named mkSense, which enables their intercommunication. Moreover, we describe the design and implementation of a software library which can be used for building “intelligent software” for the Web of Things. View full abstract»

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  • Design of a Comb Generator for High Capacity Coherent-WDM Systems

    Publication Year: 2012 , Page(s): 1690 - 1696
    Cited by:  Papers (1)
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    This paper presents a theoretical model developed for estimating the power, the optical signal to noise ratio and the number of generated carriers in a comb generator, having as a reference the minimum optical signal do noise ratio at the receiver input, for a given fiber link. Based on the recirculating frequency shifting technique, the generator relies on the use of coherent and orthogonal multi-carriers (Coherent-WDM) that makes use of a single laser source (seed) for feeding high capacity (above 100 Gb/s) systems. The theoretical model has been validated by an experimental demonstration, where 23 comb lines with an optical signal to noise ratio ranging from 25 to 33 dB, in a spectral window of ~ 3.5 nm, are obtained. View full abstract»

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  • Efficient Robust Broadband Beamforming Algorithms Using Variable Loading

    Publication Year: 2012 , Page(s): 1697 - 1702
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    Steering angle errors are known to be a major cause of performance degradation of adaptive beamformers, especially when the signal of interest is present in the measurements. Diagonal loading is one of the most widely used and effective methods to improve robustness of adaptive beamformers. This paper presents two robust beamforming algorithms using efficient realisation techniques. The techniques do not use a pre-steered array and allow an array designer to specify the frequency response of the processor in the look direction and steered the main beam of specified frequency response in an arbitrary direction. The proposed techniques are computationally efficient. The techniques used in the paper extend two previously published techniques used for narrow band beamforming to broadband beamforming. Simulation results exhibit enhanced robustness performance of the broadband beamformer. View full abstract»

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  • Frequency-Reuse Planning of the Down-Link of Distributed Antenna Systems with Maximum-Ratio-Combining (MRC) Receivers

    Publication Year: 2012 , Page(s): 1703 - 1709
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    Distributed antenna systems (DAS) have been shown to considerably outperform conventional cellular systems in terms of capacity improvement and interference resilience. However, the influence of frequency reuse planning on the performance of DAS remains relatively unknown. To partially fill this gap, this paper presents a comparative analysis of the down-link of DAS versus conventional cellular systems using different values of frequency reuse factor. The analysis assumes Rayleigh fading channels and it also considers maximum-ratio-combining (MRC) receivers at the user terminals to exploit diversity both in the transmission and reception links. Numerical evaluation of the analytical expressions shows that, in general, for most of the cases DAS can achieve better performance figures than conventional cellular systems using considerably smaller values of frequency reuse factor. Conversely, DAS can significantly improve the throughput (2x-3x) and power consumption (6-10 dB) of conventional systems when using the same frequency reuse factor. An interesting result shows that in some particular cases DAS outperform conventional cellular systems no matter the frequency reuse factor used by the latter one, which indicates an effective capacity gain provided by the combined operation of DAS and MRC receivers. View full abstract»

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  • Improving Out-of-Band Power Emissions in OFDM Systems using Double-length Symbols

    Publication Year: 2012 , Page(s): 1710 - 1718
    Cited by:  Papers (1)
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    A method that improves the out-of-band power emissions in wireless systems that use orthogonal frequency division multiplexing (OFDM) in their air interface is proposed in this paper. The key idea behind this approach is to obtain the output signal using an inverse discrete Fourier transform (IDFT) calculation with double length, when compared to the single-length IDFT computation that takes place in a conventional OFDM system. Double-length symbols provide implicit continuity in half of the original union points of the whole transmission, and can be used in conjunction with other well-known techniques already proposed in the literature (e.g., spectral precoding). The use of cyclic prefix and suffix strategies is also presented for time-varying channels, enabling the accommodation of the output signal in the same original bandwidth (i.e., without affecting the sampling rate). Obtained results show important reductions in the out-of-band power emissions, which can be even further improved when combined with rate-one spectral precoding techniques. Since the output signal is completely obtained in a digital way, the proposed approach is suitable for future applications that are foreseen in the area of software defined radio (SDR) and cognitive radio (CR). View full abstract»

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  • Toward Flexible Security and Trust Hardware Structures for Mobile-Portable Systems

    Publication Year: 2012 , Page(s): 1719 - 1722
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    Mobile and portable computing devices are claiming an increasingly big part of recent and future IT user applications. However, in security demanding environments like financial, government or crisis management systems, the mobile, portable world is unable to provide a strong security infrastructure capable of supporting a high level of trust to related mobile applications. In this paper, we discuss the existing hardware attempts toward providing strong security and trust mechanisms for mobile-portable systems. We focus our analysis on the Trusted Computing Group initiative for mobile trust and highlight the design and implementation problems of such endeavor. We propose using hardware efficient cryptographic algorithms for the Hardware mobile trust environments capable of supporting flexible security protocols and suggest Elliptic Curve cryptography and associated Pairing Based protocols as the best approach toward this end. View full abstract»

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  • Design and performance considerations in stand alone PV powered telecommunication systems

    Publication Year: 2012 , Page(s): 1723 - 1729
    Cited by:  Papers (3)
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    With the continuous increase observed in stand alone photovoltaic (SAPV) systems powering telecommunication stations worldwide, the deeper understanding of factors which significantly affect the short and long term performance of the SAPV becomes a necessity. This paper analyses design and performance considerations and factors that affect the performance of the SAPV such as PV sizing, the effect of shadowing, temperature, and dust, and shows how these can lead to reduction in power output of the SAPV and cause a permanent progressive degradation of the PV cells and the entire PV generator. The need for standardized maintenance procedures and remote monitoring and inspection is highlighted, and a careful design phase is promoted for SAPV systems to remain a preferred power alternative for telecommunication applications. View full abstract»

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  • A non-reducible Meyer‑Muller's like elliptic curve cryptosystem

    Publication Year: 2012 , Page(s): 1730 - 1733
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    In this paper we present a novel variant of Meyer-M-uller's elliptic curve cryptosystem. Unlike Meyer- M-uller's proposal and its Chua-Ling's variant, the one presented here is not reducible to Rabin-Williams' cryptosystem. This is formally proven under the assumption that computing half points on elliptic curves defined over the ring Z/nZ is hard when the factorization of n is unknown. View full abstract»

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  • A Traffic Classification Agent for Virtual Networks Based on QoS Classes

    Publication Year: 2012 , Page(s): 1734 - 1741
    Cited by:  Papers (1)
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    Internet growth drives the emergence and usage of new applications, which have specific requirements for Quality of Service (QoS). Thus, differentiation of packets which belong to certain QoS classes becomes a crucial factor to ensure the desirable quality for the applications. Within this context, this paper proposes an agent for real-time traffic classification based on QoS classes for virtual network environments, which aims at forwarding the flow to the adequate virtual network according to the QoS class. The study was made using the Mininet emulator and the Openflow Protocol. And the study showed that the agent using the Naive Bayes method performs the more suitable classification in real time. View full abstract»

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  • ACTkit: A Framework for the Definition and Enforcement of Role, Content and Context-based Access Control Policies

    Publication Year: 2012 , Page(s): 1742 - 1751
    Cited by:  Papers (1)
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    This work describes a framework, called ACTkit, for the definition and enforcement of dynamic access control policies on (multi-tiered) information systems. ACTkit embodies a language for defining security policies built out of role-, context- and content-based access control rules and an access control module responsible for the policy enforcement. A model, which has been defined as an extension of Hierarchical RBAC to provide a precise semantics for the security policies, is also presented and discussed. View full abstract»

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  • Aiming at Higher Network Security through Extensive Penetration Tests

    Publication Year: 2012 , Page(s): 1752 - 1756
    Cited by:  Papers (3)
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    Modern enterprise infrastructures adopt multilayer network architectures and heterogeneous server environments in order to efficiently fulfill each organization's goals and objectives. These complex network architectures have resulted in increased demands of information security measures. Each organization needs to effectively deal with this major security concerns, forming a security policy according to its requirements and objectives. An efficient security policy must be proactive in order to provide sufficient defense layers against a variety of known and unknown attack classes and cases. This proactive approach is usually interpreted wrongly in only up-to-date software and hardware. Regular updates are necessary, although, not enough, because potential mis-configurations and design flaws cannot be located and patched, making the whole network vulnerable to attackers. In this paper we present how a comprehensive security level can be reached through extensive Penetration Tests (Ethical Hacking). We present a Penetration Test methodology and framework capable to expose possible exploitable vulnerabilities in every network layer. Additionally, we conducted an extensive analysis of a network penetration test case study against a network simulation lab setup, exposing common network mis-configurations and their security implications to the whole network and its users. View full abstract»

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  • Analysis and Implementation of Anti-Forensics Techniques on ZFS

    Publication Year: 2012 , Page(s): 1757 - 1766
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    This paper presents a strategy to implement anti-forensics techniques on ZFS file system developed by Sun Microsystems (Oracle Corporation) that brings benefits and functionality based on easy administration and robust design. The forensic research in this file system has already started and in this work we apply the anti-forensic methods, thinking that the solution to these problems lies in understanding the own details of this file system. View full abstract»

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  • Analyzing characteristics of malicious PDFs

    Publication Year: 2012 , Page(s): 1767 - 1773
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    This paper presents an analysis of some characteristics from malicious PDFs files. This characteristics where examined on a testbed of 11,104 malicious and 8,668 non malicious files, the malicious samples includes some 0days and files used on the wild for focused attacks. The PDF format is showed very quickly only to help understand the attack vectors. The malicious PDF files attacks are on the wild for almost three years, and recently this kind of attacks are incrementing, and the techniques used to hide from anti-virus software are growing in complex, so this is why is important now to work on understand how this malicious PDF files are formed. View full abstract»

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  • Anonymous, Fair and Untraceable Micropayment Scheme: Application to LBS

    Publication Year: 2012 , Page(s): 1774 - 1784
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    The new mobile devices can access data networks and they can also execute complex applications. In this work, we present the first micropayment system adapted to these devices, accomplishing the security properties that guarantees the privacy of users and avoids the financial risks. Moreover, the payment phase has been designed as a fair exchange, where the user U sends coupons to the provider P and U will receive the requested good, information or service. Along this fair exchange, the anonymity and the untraceability of users are assured. We should take into account that the current smart-phones have a lot of computation capabilities and they also have location systems like GPS. The combination of both technologies can be useful to build new ubiquitous applications and services based on the user location. In our work, we also show how our micropayment scheme can be adapted to the payment of Location-Based Services (LBS) using mobile devices and assuring the security requirements. View full abstract»

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  • Assessment Model for Opportunistic Routing

    Publication Year: 2012 , Page(s): 1785 - 1790
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    This paper proposes an assessment model, based on a new taxonomy, which comprises an evaluation guideline with performance metrics and experimental setup to aid designers in evaluating solutions through fair comparisons. Simulation results are provided based on the proposed model considering Epidemic, PROPHET, Bubble Rap, and Spray and Wait, and showing how they perform under the same set of metrics and scenario. View full abstract»

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  • Children and Adolescent Risk Environment Characterization to Use Information Technologies and Communications (ICT): Case Merida, Venezuela

    Publication Year: 2012 , Page(s): 1791 - 1797
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    To care and protect children is, undoubtedly, one of the most important indicators of civic development in society. In the context of relationships established between the children and new technologies, especially the Internet, there have been two positions: one of them is in favor to use Internet as an educational tool and the other one establishes the need to protect children against the risks of its use. This paper describes the results of a research carried out in 2009-2010 in the city of Mérida, Venezuela. We used statistical analysis to establish statistically significant relationships between the characteristics of minors who use the Internet and their likelihood of being victims of crime through web. Results allowed us to define the profiles of young who lives in Merida in relation to technologies and the risk of its use, emphasizing that 5 of 10 children interviewed had had personal contact with individuals that they knew through the internet. Finally, it could be proven that the likelihood of risk that children and youth users of Information Technology and Communication ICT, is determined by the modes of use (time and place of use, safety measures, etc.) and certain demographic characteristics (age, education level, etc.). View full abstract»

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  • Computational Intelligence Applied on Cryptology: a brief review

    Publication Year: 2012 , Page(s): 1798 - 1810
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    Many cryptographic techniques have been developed and several were broken. Recently, new models have arisen with different and more complex approaches to cryptography and cryptanalysis, like those based on the Computational Intelligence (CI). Different bio-inspired techniques can be found in the literature showing their effectiveness in handling hard problems in the area of cryptology. However, some authors recognize that the advances have been slow and that more efforts are needed to take full advantage of CI techniques. In this work, we present a brief review of some of the relevant works in this area. The main objective is to better understand the advantages of applying CI on cryptology in the search for new ways of improving computer security. View full abstract»

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  • Impact of Churn on Object Management Policies Deployed in CDN-P2P Systems

    Publication Year: 2012 , Page(s): 1811 - 1816
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    In this paper, we study the impact of churn on object management policies deployed in a CDN-P2P system. The effectiveness of buffer enlargement and replicating control, in reducing the effects of churn on these policies, is analyzed. We have found that neither the simply enlargement of peers' storage capacity nor a zero replicating strategy are effective actions to improve performance of an object management policy. Policies that implements different caching strategies are evaluated, and a YouTube video collection, which records over 1.6 million video's log, is used in our experimental studies. View full abstract»

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  • Internet Traffic Classification Using the Index of Variability

    Publication Year: 2012 , Page(s): 1817 - 1823
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (590 KB)  

    Internet Traffic Classification aims at the identification of the Internet application that generates a given sequence of packets. Shallow Packet Inspection (SPI) is a new family of classification techniques that only use information available in the external header of packets and the statistical characterization of the traffic process. Therefore, these techniques are applicable even to encrypted or obfuscated traffic. The packet arrival process is a particularly interesting features for traffic classification, as it is difficult to significantly modify it. This paper proposes a classification technique based on a classification feature called Index of Variability, which evaluates the traffic source burstiness over various time scales in order to discriminate among different classes of Internet applications. Experimental results show that this classification method operates effectively both on synthetic and real traffic traces. Synthetic traffic traces make it possible to estimate the classification error rate achieved by the classification algorithm. The usage of real traces allows us to compare the performance of the method to the performance obtained with Deep Packet Inspection (DPI) techniques, showing that SPI and DPI yields similar results. View full abstract»

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  • LOPD Compliance and ISO 27001 legal requirements in the Health Sector

    Publication Year: 2012 , Page(s): 1824 - 1837
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    In a society based on information, the Safety Management Systems (ISMS) are increasingly critical for businesses. Within the Management of Information Security issues are very critical in certain sectors, such as the processing of personal data for the Health Sector, where a bad use of them can mean irreparable damage to their owners and organizations are obligation to protect them. This paper presents a real case of success that allowed to solve issues related to privacy of patient information at the time of making the quotation of these consultations, as well as compliance with the Organic Law for the protection of Personal Data (OLPD) in environments health and other benefits of the implemented solution. View full abstract»

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  • Performance Evaluation of a Scheduler for the ONU-BS of Integrated EPON-WiMAX Networks

    Publication Year: 2012 , Page(s): 1838 - 1843
    Cited by:  Papers (1)
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    The integration of WiMAX networks with EPON networks combine the large bandwidth availability in optical access networks with the mobility provided by wireless technologies. In this integration, a WiMAX bandwidth scheduler that takes into account the variability of the channel capacity provided by the EPON scheduler is quite important, since the granted bandwidth must be sufficient to support the QoS of WiMAX connections. This paper evaluates the performance of a standard-compliant WiMAX uplink scheduler designed to the ONU-BS. The evaluation is conducted using integrated simulators for the WiMAX and for the EPON components. Simulation results show that the proposed scheduler is able to provide QoS to the subscriber stations. View full abstract»

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  • Real-Time Industrial Communication over IEEE802.11e Wireless Local Area Networks

    Publication Year: 2012 , Page(s): 1844 - 1849
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    This paper proposes a real-time communication scheme for wireless local area network (WLAN) infrastructure. This strategy was called Group Sequential Communication (GSC). The GSC has the main goal to reduce the network overhead due to the Polling, Ack and QoS Null Frames of Hybrid Coordination Function Controlled Channel Access (HCCA) in IEEE 802.11e, because it uses a Virtual Token Passing procedure to priority the real-time communication over WLAN. In order to improve the confiability of the new scheme is presented a fault-tolerant mechanism based on Block-Ack strategy to avoid missing real-time messages. The GSC was implemented in NS2 and simulation results have proved the superior performance of GSC in comparison with HCCA for real-time industrial communications. View full abstract»

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  • Ubiquitous computing multidisciplinary endeavour

    Publication Year: 2012 , Page(s): 1850 - 1852
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    Nowadays, an increasing number of sensors are becoming embedded in the everyday objects or in the environment at a low cost. Accordingly, our living environments are populated by an increasing number of artefacts, i.e., objects enhanced with sensing, computation and networking abilities. In addition, people are increasingly using mobile devices as intermediaries between themselves and the artefacts. As a result of this continuing trend, an elementary Ambient Intelligence (AmI) infrastructure has become installed, though still fragmented, information appliances are commercially available, and Ubiquitous Computing (UbiComp) applications are being deployed. This paper discusses the course of UbiComp evolution since its inception and the inevitable criticality of interdisciplinary approaches in UbiComp. We conclude by highlighting the impact of UbiComp introduction in society and future opportunities that may rise in this exciting field of science. 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
Mirela Sechi Moretti Annoni Notare
mirela@ieee.org
+55(48)9981-4823