132 research outputs found

    Adaptation of variable-bit-rate compressed video for transport over a constant-bit-rate communication channel in broadband networks.

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    by Chi-yin Tse.Thesis (M.Phil.)--Chinese University of Hong Kong, 1995.Includes bibliographical references (leaves 118-[121]).Chapter 1 --- Introduction --- p.1Chapter 1.1 --- Video Compression and Transport --- p.2Chapter 1.2 --- VBR-CBR Adaptation of Video Traffic --- p.5Chapter 1.3 --- Research Contributions --- p.7Chapter 1.3.1 --- Spatial Smoothing: Video Aggregation --- p.8Chapter 1.3.2 --- Temporal Smoothing: A Control-Theoretic Study。 --- p.8Chapter 1.4 --- Organization of Thesis --- p.9Chapter 2 --- Preliminaries --- p.13Chapter 2.1 --- MPEG Compression Scheme --- p.13Chapter 2.2 --- Problems of Transmitting MPEG Video --- p.17Chapter 2.3 --- Two-layer Coding and Transport Strategy --- p.19Chapter 2.3.1 --- Framework of MPEG-based Layering --- p.19Chapter 2.3.2 --- Transmission of GS and ES --- p.20Chapter 2.3.3 --- Problems of Two-layer Video Transmission --- p.20Chapter 3 --- Video Aggregation --- p.24Chapter 3.1 --- Motivation and Basic Concept of Video Aggregation --- p.25Chapter 3.1.1 --- Description of Video Aggregation --- p.28Chapter 3.2 --- MPEG Video Aggregation System --- p.29Chapter 3.2.1 --- Shortcomings of the MPEG Video Bundle Scenario with Two-Layer Coding and Cell-Level Multiplexing --- p.29Chapter 3.2.2 --- MPEG Video Aggregation --- p.31Chapter 3.2.3 --- MPEG Video Aggregation System Architecture --- p.33Chapter 3.3 --- Variations of MPEG Video Aggregation System --- p.35Chapter 3.4 --- Experimental Results --- p.38Chapter 3.4.1 --- Comparison of Video Aggregation and Cell-level Multi- plexing --- p.40Chapter 3.4.2 --- Varying Amount of the Allocated Bandwidth --- p.48Chapter 3.4.3 --- Varying Number of Sequences --- p.50Chapter 3.5 --- Conclusion --- p.53Chapter 3.6 --- Appendix: Alternative Implementation of MPEG Video Aggre- gation --- p.53Chapter 3.6.1 --- Profile Approach --- p.54Chapter 3.6.2 --- Bit-Plane Approach --- p.54Chapter 4 --- A Control-Theoretic Study of Video Traffic Adaptation --- p.58Chapter 4.1 --- Review of Previous Adaptation Schemes --- p.60Chapter 4.1.1 --- A Generic Model for Adaptation Scheme --- p.60Chapter 4.1.2 --- Objectives of Adaptation Controller --- p.61Chapter 4.2 --- Motivation for Control-Theoretic Study --- p.64Chapter 4.3 --- Linear Feedback Controller Model --- p.64Chapter 4.3.1 --- Encoder Model --- p.65Chapter 4.3.2 --- Adaptation Controller Model --- p.69Chapter 4.4 --- Analysis --- p.72Chapter 4.4.1 --- Stability --- p.73Chapter 4.4.2 --- Robustness against Coding-mode Switching --- p.83Chapter 4.4.3 --- Unit-Step Responses and Unit-Sample Responses --- p.84Chapter 4.5 --- Implementation --- p.91Chapter 4.6 --- Experimental Results --- p.95Chapter 4.6.1 --- Overall Performance of the Adaptation Scheme --- p.97Chapter 4.6.2 --- Weak-Control verus Strong-Control --- p.99Chapter 4.6.3 --- Varying Amount of Reserved Bandwidth --- p.101Chapter 4.7 --- Conclusion --- p.103Chapter 4.8 --- Appendix I: Further Research --- p.103Chapter 4.9 --- Appendix II: Review of Previous Adaptation Schemes --- p.106Chapter 4.9.1 --- Watanabe. et. al.'s Scheme --- p.106Chapter 4.9.2 --- MPEG's Scheme --- p.107Chapter 4.9.3 --- Lee et.al.'s Modification --- p.109Chapter 4.9.4 --- Chen's Adaptation Scheme --- p.110Chapter 5 --- Conclusion --- p.116Bibliography --- p.11

    A control-theoretic approach to adapting VBR compressed video for transport over a CBR communications channel

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    Application of Finite-Time Stability Concepts to the Control of ATM Networks

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    When dealing with the stability of a system, a distinction should be made between classical Lyapunov Stability and Finite-Time Stability (FTS) (or Short-Time Stability). The concept of Lyapunov Asymptotic Stability is largely known to the control community; on the other hand a system is said to be finite-time stable if, once we fix a time-interval, its state does not exceeds some bounds during this time-interval. Often asymptotic stability is enough for practical applications, but there are some cases where large values of the state are not acceptable, for instance in the presence of saturations. In these cases, we need to check that these unacceptable values are not attained by the state; for these purposes FTS could be used. Some early results on FTS can be found in [9], [12] and [8]; more recently the concept of FTS has been revisited in the light of recent results coming from Linear Matrix Inequalities (LMIs) theory, which has allowed to find less conservative conditions guaranteeing FTS and finite time stabilization of uncertain, linear continuous-time systems (see [3]). In this note we consider the problem of applying some sufficient conditions for finite time stabilization to design the control algorithm of an ATM network described via a discrete-time system. The extended abstract is organized as follows: in Section 2 we provide a sufficient condition for finite time stabilization of a discrete time system; in Section 3 we detail the model of an ATM network; finally in Section 4 some concluding remarks and plans for the final version of the paper are given

    A study of the transmission of VBR encoded video over ATM networks.

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    by Ngai Li.Thesis (M.Phil.)--Chinese University of Hong Kong, 1997.Includes bibliographical references (leaves 66-69).Chapter 1 --- Introduction --- p.1Chapter 1.1 --- Video Compression and Transport --- p.2Chapter 1.2 --- Research Contributions --- p.6Chapter 1.2.1 --- Joint Rate Control of VBR Encoded Video --- p.6Chapter 1.2.2 --- Transporting VBR Video on LB Controlled Channel --- p.7Chapter 1.3 --- Organization of Thesis --- p.7Chapter 2 --- Preliminary --- p.9Chapter 2.1 --- Statistical Characteristics of MPEG-1 Encoded Video --- p.9Chapter 2.2 --- Temporal and Spatial Smoothing --- p.14Chapter 2.2.1 --- Temporal Smoothing --- p.14Chapter 2.2.2 --- Spatial Smoothing --- p.15Chapter 2.3 --- A Single Source Control-Theoretic Framework for VBR-to-CBR Video Adaptation --- p.16Chapter 3 --- Joint Rate Control of VBR Encoded Video --- p.19Chapter 3.1 --- Analytical Models --- p.21Chapter 3.2 --- Analysis --- p.27Chapter 3.2.1 --- Stable Region --- p.29Chapter 3.2.2 --- Final Value of the State Variables --- p.33Chapter 3.2.3 --- Peak Values of Buffer-occupancy Deviation and Image- quality Fluctuation --- p.35Chapter 3.2.4 --- SAE of Buffer-occupancy Deviation and Image-quality Fluc- tuation --- p.42Chapter 3.3 --- Experimental Results --- p.43Chapter 3.4 --- Concluding Remarks --- p.48Chapter 4 --- Transporting VBR Video on LB Controlled Channel --- p.50Chapter 4.1 --- Leaky Bucket Access Control --- p.51Chapter 4.2 --- Greedy Token-usage Strategy --- p.53Chapter 4.3 --- Non-greedy Token-usage Strategy --- p.57Chapter 4.4 --- Concluding Remarks --- p.60Chapter 5 --- Conclusions --- p.62Chapter 5.1 --- Joint Rate Control of Multiple VBR Videos --- p.62Chapter 5.2 --- LB Video Compression --- p.63Chapter 5.3 --- Further Study --- p.64Chapter 5.4 --- Publications --- p.65Bibliography --- p.6

    Dynamic bandwidth allocation in ATM networks

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    Includes bibliographical references.This thesis investigates bandwidth allocation methodologies to transport new emerging bursty traffic types in ATM networks. However, existing ATM traffic management solutions are not readily able to handle the inevitable problem of congestion as result of the bursty traffic from the new emerging services. This research basically addresses bandwidth allocation issues for bursty traffic by proposing and exploring the concept of dynamic bandwidth allocation and comparing it to the traditional static bandwidth allocation schemes

    Design of a transport coding scheme for high-quality video over ATM networks

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    Caption title.Includes bibliographical references (p. 38-39).Supported by ARPA. F30602-92-C-0030 Supported by the Laboratory for Information and Decision Systems, Massachusetts Institute of Technology. DAAH04-95-1-0103V. Parthasarathy, J.W. Modestino and K.S. Vastola

    Traffic Management and Congestion Control in the ATM Network Model.

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    Asynchronous Transfer Mode (ATM) networking technology has been chosen by the International Telegraph and Telephony Consultative Committee (CCITT) for use on future local as well as wide area networks to handle traffic types of a wide range. It is a cell based network architecture that resembles circuit switched networks, providing Quality of Service (QoS) guarantees not normally found on data networks. Although the specifications for the architecture have been continuously evolving, traffic congestion management techniques for ATM networks have not been very well defined yet. This thesis studies the traffic management problem in detail, provides some theoretical understanding and presents a collection of techniques to handle the problem under various operating conditions. A detailed simulation of various ATM traffic types is carried out and the collected data is analyzed to gain an insight into congestion formation patterns. Problems that may arise during migration planning from legacy LANs to ATM technology are also considered. We present an algorithm to identify certain portions of the network that should be upgraded to ATM first. The concept of adaptive burn-in is introduced to help ease the computational costs involved in virtual circuit setup and tear down operations

    Preliminary study of cooperation in hybrid ad-hoc networks

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    In this paper, we present a first approach to evolve a cooperative behavior in ad hoc networks. Since wireless nodes are energy constrained, it may not be in the best interest of a node to always accept relay requests. On the other hand, if all nodes decide not to expend energy in relaying, then network throughput will drop dramatically. Both these extreme scenarios are unfavorable to the interests of a user. In this paper we deal with the issue of user cooperation in ad hoc networks by developing the algorithm called Generous Tit-For-Tat. We assume that nodes are rational, i.e., their actions are strictly determined by self-interest, and that each node is associated with a minimum lifetime constraint. Given these lifetime constraints and the assumption of rational behavior, we study the added behavior of the network.En este proyecto mostramos un primer acercamiento a la evolución de las redes Ad-Hoc cooperativas. Puesto que los nodos wireless disponen de energía finita, puede que no estén interesados en aceptar transmitir tráfico de otros nodos. Por otra parte, si ningún nodo decide gastar energía en retransmitir tráfico de otros, entonces la tasa de transferencia en la red cae críticamente. Estos casos extremos son desfavorables para el usuario. En este trabajo tratamos estas cuestiones gracias al desarrollo de un algoritmo llamado "Generous Tit-For Tat". Asumiremos que los nodos son egoístas y tienen energía finita, así que las decisiones se determinarán por propio interés y cada nodo será asociado con un tiempo limitado de energía. Dadas esas limitaciones y la suposición del comportamiento racional estudiaremos el comportamiento agregado de la red.En aquest treball mostrem una primera aproximació a l'evolució de les xarxes Ad-Hoc cooperatives. Donat que els nodes wireless disposen d'energia finita, poden no estar interessats en transmetre tràfic d'altres nodes. Per altra banda, si cap node decideix gastar energia en passar tràfic d'altres, llavors la tassa de transferència a la xarxa cau críticament. Aquests casos extrems son desfavorables per l'usuari. En aquest treball tractem aquestes qüestions gràcies al desenvolupament d'un algoritme anomenat "Generous Tit-For-Tat". Assumirem que els nodes son egoistes y tenen energia finita, així que les decisions es determinaran pel seu propi interès i cada node s'associarà amb un temps limitat d'energia. Donades aquestes limitacions y la suposició del comportament racional, estudiarem el comportament agregat de la xarxa.Nota: Aquest document conté originàriament altre material i/o programari només consultable a la Biblioteca de Ciència i Tecnologia
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