With their tremendous success in broadcasting entertainment services, digital satellite systems are rapidly being viewed as viable service delivery vehicles. In parallel, both the demand for internet and multimedia se...
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ISBN:
(纸本)0780357973
With their tremendous success in broadcasting entertainment services, digital satellite systems are rapidly being viewed as viable service delivery vehicles. In parallel, both the demand for internet and multimedia services and the subsequent end-user demand for higher bandwidth are forcing network operators to search for mechanisms that can cost effectively provide high speed access to end-users. network operators are seriously considering satellite based networks to offer broadband and multimedia services to supplement and enhance their existing terrestrial networks. One solution is based on a geosynchronous (GEO) satellite system equipped with on-board processing and switching. Allowing for a maximum number of simultaneous users is an important element of this system, hence requiring effective connection admission control (CAC) and bandwidth on demand (BOD) algorithms. In this paper, a CAC scheme is studied for the uplink segment of a broadband GEO satellite network with an on-board ATM-like switch. A MF-TDMA scheme is used for the uplink access. The CAC algorithm investigated is ATM-based with heterogeneous traffic traversing the satellite network. performance evaluations of the CAC algorithm are done by detailed simulations. Connection blocking performance results are given for each type of traffic in the system.
In this paper, a stable adaptive fuzzy output tracking control scheme is developed for a single-input-single-output unknown nonlinear system. The main characteristics of the proposed adaptive fuzzy are: i) it does not...
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In this paper, a stable adaptive fuzzy output tracking control scheme is developed for a single-input-single-output unknown nonlinear system. The main characteristics of the proposed adaptive fuzzy are: i) it does not need the assumption that all the states of the system are available for full feedback, but introduces a high gain observer to estimate them. ii) it is composed of a robust control term and an equivalence fuzzy control so that it not only ensures the stability of closed -loop system, but also attenuates the effect of fuzzy approximation error on the tracking error of the system to arbitrary small level. iii) it is proved that the designed output feedback adaptive fuzzy control can recover the performance achieved under the state feedback controller.
We describe the design and implementation of secure network objects, which provide security for object-oriented network communication. The design takes advantage of objects and subtyping to present a simple but expres...
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Congestion control avoidance in computer networks is still a major unresolved issue. The applicability of previous congestion control mechanisms has to be demonstrated taking into account today's constraints. In t...
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ISBN:
(纸本)0819434353
Congestion control avoidance in computer networks is still a major unresolved issue. The applicability of previous congestion control mechanisms has to be demonstrated taking into account today's constraints. In this work, several schemes are studied in order to support differentiated services in a wide area, very high speed network. A three Class-of-Service (CoS) system is considered with various types of traffic. Node is then modelled by a tree queue system, each of which is dedicated to a set of traffic type. Fairness considerations are managed by the scheduling algorithm according to the priority of each CoS. Most of the traffic, particularly best effort traffic, remains bursty. Therefore, the aggregation of Markov Modulated sources used in this study attempts to generate realistic burstiness properties. Congestion control mechanisms deal with the well-known transient nature of the system behavior. In this context, there are some difficulties to establish relevant parameters for congestion state identification. The time-scale problem mainly lies in the congestion detection and the response-time of the congestion control mechanism. Several methods are compared according to various performance parameters such as delay, loss, average throughput or oscillations in traffic load. Those methods have to deal with two orthogonal constraints. One is to rub out transient behavior and imply a statistical view of the node state which takes time. The other is to react as soon as possible when a congestion occurs, that is to minimize response-time. Another issue addressed in this study is the action that sources take when a congestion is signaled. We evaluate the impact of control parameters for Additive/Multiplicative, Increase/Decrease algorithm applied to the source.
This paper describes advanced latency reduction architecture to serve MPEG-1 layer 3 (MP3) sound stream over low bit rate links with IPv6 PPP and its experimentation. Our new technique totally manages late frames and ...
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ISBN:
(纸本)0819434388
This paper describes advanced latency reduction architecture to serve MPEG-1 layer 3 (MP3) sound stream over low bit rate links with IPv6 PPP and its experimentation. Our new technique totally manages late frames and delay jitters in conjunction with rate adjustable stream service in application and jitter control mechanism in data link layer. We have implemented a new IPv6 PPP and rate control scheme experimentally under BSD Unix to fit slow links. We have also measured performance to decide QoS parameters carefully so it will be suitable for use in the real world.
With the increasing requirement for more bandwidth and high-speed networks, the asynchronous transfer mode (ATM) has become the main consideration of many academic and industrial entities. Also, the internet growth an...
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Linear Increase/Multiplicative Decrease (LIMD) has typically been the congestion control paradigm of choice in the traditional internet with tail-drop routers. In recent years, routers with fair packet dropping polici...
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Linear Increase/Multiplicative Decrease (LIMD) has typically been the congestion control paradigm of choice in the traditional internet with tail-drop routers. In recent years, routers with fair packet dropping policies (e.g. RED) are increasingly being deployed in the internet. In the context of a network with fair packet dropping routers, we challenge the popular notion that Linear Increase/Linear Decrease (LILD) is an unsuitable paradigm for congestion control, and present two key results: (a) LILD is both efficient and fair in the target environment. In fact, LILD outperforms LIMD in most respects. (b) By maintaining the history of transmission rates and loss profiles, congestion control algorithms can effectively distinguish between congestion-induced and non-congestion-induced loss. We present the LILD/H algorithm that combines the above features. LILD/H reacts gently to random/channel probe loss, and aggressively to congestion loss, thereby adapting effectively to the dynamics of the network. Consequently, we believe that LILD/H is a viable congestion control algorithm at the end host or the edge router in the future internet.
Local Multipoint Distribution Service is a solution to the "last mile problem" far broadband digital service access systems. A two-layer cellular network architecture can be used to increase signal coverage....
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ISBN:
(纸本)3540660828
Local Multipoint Distribution Service is a solution to the "last mile problem" far broadband digital service access systems. A two-layer cellular network architecture can be used to increase signal coverage. In such networks, a Multiple Access control (MAC) protocol is needed to manage the two-way communications between LMDS providers and their users. A novel MAC layer has been proposed for use in the EU/ACTS project CABSINET. However, the MAC layer should also be able to bear multiple service classes in order to support future users with a range of applications such as voice and internet access, as well as the video services. This paper presents an analysis of the CABSINET MAC layer performance when considered for use with multiple traffic types.
This paper presents a comparative study of parametric and structural identification methodologies when applied to the identification of an experimental nonlinear process. Several approaches for parametric identificati...
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This paper presents a comparative study of parametric and structural identification methodologies when applied to the identification of an experimental nonlinear process. Several approaches for parametric identification are presented, such as: i) linear mathematical model obtained through recursive least-squares (RLS), ii) linear model with estimation algorithm using multi-step-ahead, iii) Hammerstein model, iv) Volterra model and, v) bilinear model. Two structural approaches for neural network configuration are used: i) multilayer perceptron, and vii) radial basis function. An experimental evaluation is performed on a fan-and-plate process which exhibits complex features. Main characteristics of each identification methodologies and experimental results are assessed and compared using performance indices and validation response curves.
The proceedings contain 183 papers. The topics discussed include: enhancing survivability of mobile internet access using mobile IP with location registers;a new mobility model and its application in the channel holdi...
ISBN:
(纸本)0780354176
The proceedings contain 183 papers. The topics discussed include: enhancing survivability of mobile internet access using mobile IP with location registers;a new mobility model and its application in the channel holding time characterization in PCs network;hop-by-hop routing with node-dependent topology information;accessing multiple mirror sites in parallel: using tornado codes to speed up downloads;an effective and efficient traffic smoothing scheme for delivery of online VBR media streams;bounds on the performance of admission control and routing policies for general topology networks with multiple call classes;techniques for optimizing CORBA middleware for distributed embedded systems;supporting dynamic inter-class resource sharing: a multi-class QoS routing algorithm;a framework for call admission control and QoS support in wireless environments;integrated scheduling of unicast and multicast traffic in an input-queued switch;and RAP: an end-to-end rate-based congestion control mechanism for realtime streams in the internet.
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