10 research outputs found

    Correção de referência de relógio para fluxo de transporte MPEG-2 em FPGA

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    Dissertação (mestado) - Universidade Federal de Santa Catarina, Centro Tecnológico, Programa de Pós-Graduação em Engenharia Elétrica, Florianópolis, 2014O Fluxo de Transporte (Transport Stream - TS) MPEG-2 é um formato amplamente utilizado em sistemas de TV Digital para a transmissão de áudio, vídeo e informações relacionadas a programa. Entre outras informações, um fluxo de transporte carrega uma referência de tempo, conhecida como Referência de Relógio de Programa (Program Clock Reference - PCR), a qual é um retrato do relógio de 27 MHz do sistema. Esta informação permite a recuperação do relógio nos receptores, o qual garante a correta apresentação do conteúdo e até mesmo controla interfaces de saída. Porém, se o tempo de chegada dos pacotes de transporte variar durante a transmissão ou o processamento, tal cenário pode levar a erros no relógio do sistema, o que é conhecido como jitter. Os métodos tradicionais para a correção da informação do relógio de programa normalmente são baseadas em contadores/acumuladores de 27MHz com ponto flutuante, porém, não mitigam o jitter de PCR completamente. Métodos mais recentes usam contador/acumulador controlado por semáforo, e até mesmo propõem um esquema de adaptação de taxa integrada à correção da referência de relógio, a qual resulta em baixos níveis de jitter na saída. Além disto, não há estudos a respeito da implementação dos métodos controlados por semáforo em processadores de fluxo de transporte. Com isto, o presente trabalho propõe uma metodologia para implementação em FPGA, utilizando linguagem de descrição de hardware. Os resultados obtidos validam o uso dos métodos controlados por semáforo e mostram que a estrutura proposta é efetiva, com o benefício de eliminar efeitos de metaestabilidade.Abstract: The MPEG-2 Transport Stream is a standard format commonly used in digital TV systems for conveying audio, video and program-related information. Among other data, a transport stream also encapsulates a timing reference, known as program clock reference, which is a snapshot of the 27 MHz system clock. This information allows clock recovery in receivers, which provides correct content presentation and even drives output interfaces. However, if the arrival time of transport packets change during transmission or processing, such a scenario may lead to system clock errors, which is known as jitter. Traditional methods for correcting the program clock reference information are normally based on 27 MHz counters/floating-point accumulators and do not completely mitigate jitter. More recent methods use a semaphore-controlled counter/accumulator and even propose a joint adaptation and clock reference correction, which result in low jitter levels at the output. Nevertheless, there is no study concerning the implementation of semaphore-controlled methods in transport stream processors. Given that, the present work proposes an implementation methodology for FPGA, using hardware description language. The related results validate the use of semaphore-controlled methods and show that the proposed structure is effective, with the benefit of avoiding metastability effects

    The telecommunications and data acquisition report

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    Deep Space Network operations, engineering, and implementation are reported. Developments in Earth-based radiotechnology as applied to other research programs in the fields of Geodynamics, Astrophysics, and programs related to radio searchers (instrumentation and methods) in extraterrestrial areas in the microwave region of the electromagnetic spectrum are also presented

    A flexible medium access control framework for multimedia application support in wireless ATM

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    Includes bibliographical references.The field of wireless communications has seen phenomenal development over the last decade. With the current abundance of applications that use broadband multimedia over wired networks it is logical that users will want to have access to these same multimedia streams [rom a mobile terminal. Wireless solutions for connectivity to networks such as Ethernet networks already exist, however, a method of supporting access to an ATM network from a mobile terminal has not yet been standardised. Transporting ATM data over the wireless medium poses a number of problems. The Medium Access Control (MAC) layer of any proposed wireless ATM network would be responsible for resolving many of these problems. Unfortunately, research into MAC layers is hampered by the fact that most existing MAC layers cannot be modified in order to experiment with the effectiveness of the many MAC protocol techniques that exist

    Kommunikation und Bildverarbeitung in der Automation

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    In diesem Open-Access-Tagungsband sind die besten Beiträge des 9. Jahreskolloquiums "Kommunikation in der Automation" (KommA 2018) und des 6. Jahreskolloquiums "Bildverarbeitung in der Automation" (BVAu 2018) enthalten. Die Kolloquien fanden am 20. und 21. November 2018 in der SmartFactoryOWL, einer gemeinsamen Einrichtung des Fraunhofer IOSB-INA und der Technischen Hochschule Ostwestfalen-Lippe statt. Die vorgestellten neuesten Forschungsergebnisse auf den Gebieten der industriellen Kommunikationstechnik und Bildverarbeitung erweitern den aktuellen Stand der Forschung und Technik. Die in den Beiträgen enthaltenen anschaulichen Beispiele aus dem Bereich der Automation setzen die Ergebnisse in den direkten Anwendungsbezug

    Demystifying Internet of Things Security

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    Break down the misconceptions of the Internet of Things by examining the different security building blocks available in Intel Architecture (IA) based IoT platforms. This open access book reviews the threat pyramid, secure boot, chain of trust, and the SW stack leading up to defense-in-depth. The IoT presents unique challenges in implementing security and Intel has both CPU and Isolated Security Engine capabilities to simplify it. This book explores the challenges to secure these devices to make them immune to different threats originating from within and outside the network. The requirements and robustness rules to protect the assets vary greatly and there is no single blanket solution approach to implement security. Demystifying Internet of Things Security provides clarity to industry professionals and provides and overview of different security solutions What You'll Learn Secure devices, immunizing them against different threats originating from inside and outside the network Gather an overview of the different security building blocks available in Intel Architecture (IA) based IoT platforms Understand the threat pyramid, secure boot, chain of trust, and the software stack leading up to defense-in-depth Who This Book Is For Strategists, developers, architects, and managers in the embedded and Internet of Things (IoT) space trying to understand and implement the security in the IoT devices/platforms

    Shortest Route at Dynamic Location with Node Combination-Dijkstra Algorithm

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    Abstract— Online transportation has become a basic requirement of the general public in support of all activities to go to work, school or vacation to the sights. Public transportation services compete to provide the best service so that consumers feel comfortable using the services offered, so that all activities are noticed, one of them is the search for the shortest route in picking the buyer or delivering to the destination. Node Combination method can minimize memory usage and this methode is more optimal when compared to A* and Ant Colony in the shortest route search like Dijkstra algorithm, but can’t store the history node that has been passed. Therefore, using node combination algorithm is very good in searching the shortest distance is not the shortest route. This paper is structured to modify the node combination algorithm to solve the problem of finding the shortest route at the dynamic location obtained from the transport fleet by displaying the nodes that have the shortest distance and will be implemented in the geographic information system in the form of map to facilitate the use of the system. Keywords— Shortest Path, Algorithm Dijkstra, Node Combination, Dynamic Location (key words

    Sixth Goddard Conference on Mass Storage Systems and Technologies Held in Cooperation with the Fifteenth IEEE Symposium on Mass Storage Systems

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    This document contains copies of those technical papers received in time for publication prior to the Sixth Goddard Conference on Mass Storage Systems and Technologies which is being held in cooperation with the Fifteenth IEEE Symposium on Mass Storage Systems at the University of Maryland-University College Inn and Conference Center March 23-26, 1998. As one of an ongoing series, this Conference continues to provide a forum for discussion of issues relevant to the management of large volumes of data. The Conference encourages all interested organizations to discuss long term mass storage requirements and experiences in fielding solutions. Emphasis is on current and future practical solutions addressing issues in data management, storage systems and media, data acquisition, long term retention of data, and data distribution. This year's discussion topics include architecture, tape optimization, new technology, performance, standards, site reports, vendor solutions. Tutorials will be available on shared file systems, file system backups, data mining, and the dynamics of obsolescence

    GSI Scientific Report 2014 / GSI Report 2015-1

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