5,124 research outputs found

    Concurrent cell rate simulation of ATM telecommunications network.

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    A formalism for describing and simulating systems with interacting components.

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    This thesis addresses the problem of descriptive complexity presented by systems involving a high number of interacting components. It investigates the evaluation measure of performability and its application to such systems. A new description and simulation language, ICE and it's application to performability modelling is presented. ICE (Interacting ComponEnts) is based upon an earlier description language which was first proposed for defining reliability problems. ICE is declarative in style and has a limited number of keywords. The ethos in the development of the language has been to provide an intuitive formalism with a powerful descriptive space. The full syntax of the language is presented with discussion as to its philosophy. The implementation of a discrete event simulator using an ICE interface is described, with use being made of examples to illustrate the functionality of the code and the semantics of the language. Random numbers are used to provide the required stochastic behaviour within the simulator. The behaviour of an industry standard generator within the simulator and different methods of number allocation are shown. A new generator is proposed that is a development of a fast hardware shift register generator and is demonstrated to possess good statistical properties and operational speed. For the purpose of providing a rigorous description of the language and clarification of its semantics, a computational model is developed using the formalism of extended coloured Petri nets. This model also gives an indication of the language's descriptive power relative to that of a recognised and well developed technique. Some recognised temporal and structural problems of system event modelling are identified. and ICE solutions given. The growing research area of ATM communication networks is introduced and a sophisticated top down model of an ATM switch presented. This model is simulated and interesting results are given. A generic ICE framework for performability modelling is developed and demonstrated. This is considered as a positive contribution to the general field of performability research

    Optimistic Hard Real Time Analysis of Connectionless Self Similar Traffic in ATM Networks

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    Network parameters were referred and background traffic types reference traffic background network utilization and number of hop connections. This paper describes Asymmetric digital subscriber simulation model developed using ADSL. ADSL is integrated with IP and ATM in order to provide QOS using this model a comparison study between network using IP and ATM over ADSL is provided. In general all the proposed schemes solve many of the fundamental issues faced by optical burst switching networks thereby making more practical and efficient in the near feature. Finally the proposed algorithm were fed with this information and from their outcome we derived our results and conclusions

    High performance computing and communications: FY 1995 implementation plan

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    Augmented Thevenin Model for the Harmonic Analysis of Switching Circuits

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    This article addresses the use of the Thevenin equivalent model in the case of switching circuits. An augmented Thevenin model is proposed, based on a well-established augmented equivalent approach for the analysis of periodically switched linear networks. It can profitably be used to provide a time-invariant equivalent description of a switching network and to investigate on the harmonics behavior at any of its ports even upon the varying of one of its internal parameters. This makes the article interesting for harmonic analysis purposes as, for instance, in the analysis and troubleshooting of electromagnetic interference or in the monitoring of a system behavior through the assessment and analysis of some of its spectral components. The model has also the advantage to be simple in its implementation. The feasibility and potentiality of the method are verified via simulations and comparisons with the results obtained by applying the augmented equivalent approach to the case of a dc\u2013dc Buck converter

    Simulation and analytical performance studies of generic atm switch fabrics.

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    As technology improves exciting new services such as video phone become possible and economically viable but their deployment is hampered by the inability of the present networks to carry them. The long term vision is to have a single network able to carry all present and future services. Asynchronous Transfer Mode, ATM, is the versatile new packet -based switching and multiplexing technique proposed for the single network. Interest in ATM is currently high as both industrial and academic institutions strive to understand more about the technique. Using both simulation and analysis, this research has investigated how the performance of ATM switches is affected by architectural variations in the switch fabric design and how the stochastic nature of ATM affects the timing of constant bit rate services. As a result the research has contributed new ATM switch performance data, a general purpose ATM switch simulator and analytic models that further research may utilise and has uncovered a significant timing problem of the ATM technique. The thesis will also be of interest and assistance to anyone planning on using simulation as a research tool to model an ATM switch

    Air Traffic Control

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    Improving air traffic control and air traffic management is currently one of the top priorities of the global research and development agenda. Massive, multi-billion euro programs like SESAR (Single European Sky ATM Research) in Europe and NextGen (Next Generation Air Transportation System) in the United States are on their way to create an air transportation system that meets the demands of the future. Air traffic control is a multi-disciplinary field that attracts the attention of many researchers, ranging from pure mathematicians to human factors specialists, and even in the legal and financial domains the optimization and control of air transport is extensively studied. This book, by no means intended to be a basic, formal introduction to the field, for which other textbooks are available, includes nine chapters that demonstrate the multi-disciplinary character of the air traffic control domain

    Loosely-Tied Distributed Architecture for Highly Scalable E-Learning System

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