46 resultados para Packet switching (Data transmission)
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In a general way, in an electric power utility the current transformers (CT) are used to measurement and protection of transmission lines (TL) 1 The Power Line Carriers systems (PLC) are used for communication between electrical substations and transmission line protection. However, with the increasing use of optical fiber to communication (due mainly to its high data transmission rate and low signal-noise relation) this application loses potentiality. Therefore, other functions must be defined to equipments that are still in using, one of them is detecting faults (short-circuits) and transmission lines insulator strings damages 2. The purpose of this paper is to verify the possibility of using the path to the ground offered by the CTs instead of capacitive couplings / capacitive potential transformers to detect damaged insulators, since the current transformers are always present in all transmission lines (TL's) bays. To this a comparison between this new proposal and the PLC previous proposed system 2 is shown, evaluating the economical and technical points of view. ©2010 IEEE.
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The frequency spectrums are inefficiently utilized and cognitive radio has been proposed for full utilization of these spectrums. The central idea of cognitive radio is to allow the secondary user to use the spectrum concurrently with the primary user with the compulsion of minimum interference. However, designing a model with minimum interference is a challenging task. In this paper, a transmission model based on cyclic generalized polynomial codes discussed in [2] and [15], is proposed for the improvement in utilization of spectrum. The proposed model assures a non interference data transmission of the primary and secondary users. Furthermore, analytical results are presented to show that the proposed model utilizes spectrum more efficiently as compared to traditional models.
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The main objective is to analyze the performance of some codecs supported by Asterisk with and without encryption using RTP and SRTP, respectively, providing important data for decision-making in the implementation of a VoIP system with Asterisk. Thus, it is possible to realize both codecs as the protocol can be chosen depending on the application, or the system's main feature is the speed packet switching, security level or lower tolerance for unsuccessful calls. For this, tests were made with the codec with and without the use of cryptography to obtain some findings on the use of the same, giving more attention to the response time for the start of a call.
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Pós-graduação em Engenharia Elétrica - FEIS
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A gravidade do paciente ou o número de intervenções nem sempre serão proporcionais à carga de trabalho de enfermagem. Este estudo descritivo teve como objetivo demonstrar a trajetória da construção de um aplicativo (software) com o conteúdo do Nursing Activities Score e suas características operacionais. Foi realizado um teste piloto com 12 pacientes seguindo-se a coleta de dados por 90 dias consecutivos em 123 pacientes. Houve compatibilidade na transmissão de dados do Personal Digital Assistent para o computador de mesa, via wireless. A construção do aplicativo resultou em um sistema com coleta e administração de dados e permitiu realizar a interface gráfica. A utilização do aplicativo possibilita o uso de um sistema tecnológico para aplicação diária, com alimentação de um banco de dados sobre as características dos cuidados requeridos. Conhecendo a evolução destas variáveis durante a internação, o enfermeiro poderá planejar, intervir e avaliar a qualidade do cuidado.
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This article has the purpose to review the main codes used to detect and correct errors in data communication specifically in the computer's network. The Hamming's code and the Ciclic Redundancy Code (CRC) are presented as the focus of this article as well as CRC hardware implementation. Each code is reviewed in details in order to fill the gaps in the literature and to make it accessible to the computer science and engineering students as well as to anyone who may be interested in learning the technique to treat error in data communication.
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Currently, there has been an increasing demand for operational and trustworthy digital data transmission and storage systems. This demand has been augmented by the appearance of large-scale, high-speed data networks for the exchange, processing and storage of digital information in the different spheres. In this paper, we explore a way to achieve this goal. For given positive integers n,r, we establish that corresponding to a binary cyclic code C0[n,n-r], there is a binary cyclic code C[(n+1)3k-1,(n+1)3k-1-3kr], where k is a nonnegative integer, which plays a role in enhancing code rate and error correction capability. In the given scheme, the new code C is in fact responsible to carry data transmitted by C0. Consequently, a codeword of the code C0 can be encoded by the generator matrix of C and therefore this arrangement for transferring data offers a safe and swift mode. © 2013 SBMAC - Sociedade Brasileira de Matemática Aplicada e Computacional.
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Faced with an imminent restructuring of the electric power system, over the past few years many countries have invested in a new paradigm known as Smart Grid. This paradigm targets optimization and automation of electric power network, using advanced information and communication technologies. Among the main communication protocols for Smart Grids we have the DNP3 protocol, which provides secure data transmission with moderate rates. The IEEE 802.15.4 is another communication protocol also widely used in Smart Grid, especially in the so-called Home Area Network (HAN). Thus, many applications of Smart Grid depends on the interaction of these two protocols. This paper proposes modeling, in the traditional network simulator NS-2, the integration of DNP3 protocol and the IEEE 802.15.4 wireless standard for low cost simulations of Smart Grid applications.
Recebimento de dados GNSS via Internet em RTCM 3 e conversão para RINEX utilizando a plataforma J2ME
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Changes are occurring worldwide, including the area of positioning using Global Navigation Satellite Systems in mobile devices such as mobile phones or laptops. This is due to the great improvement and availability of Internet services to these mobile devices. The accuracy and speed of data transmission for these devices makes the technology of sending / receiving data via an internet targeted for optimization. The optimization could allow obtaining, in real-time, coordinates (latitude, longitude and altitude) of suitable quality for users of GPS (Global Positioning System) devices that have wireless Internet access, such as those used to control the eet, locomotion, navigation, agriculture, etc. . The use of the protocol NTRIP (Networked Transport of RTCM via Internet Protocol) in GPS applications is growing every day. Applications are available in C, which creates an opportunity for development with a focus on multiplatform environments. In this context, we propose an application, implemented in a multiplatform environment and the use of NTRIP, able to run on a mobile device for receiving GNSS data
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The technologies are rapidly developing, but some of them present in the computers, as for instance their processing capacity, are reaching their physical limits. It is up to quantum computation offer solutions to these limitations and issues that may arise. In the field of information security, encryption is of paramount importance, being then the development of quantum methods instead of the classics, given the computational power offered by quantum computing. In the quantum world, the physical states are interrelated, thus occurring phenomenon called entanglement. This study presents both a theoretical essay on the merits of quantum mechanics, computing, information, cryptography and quantum entropy, and some simulations, implementing in C language the effects of entropy of entanglement of photons in a data transmission, using Von Neumann entropy and Tsallis entropy.
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Pós-graduação em Ciência da Computação - IBILCE