1,545 research outputs found

    Soft Error Analysis and Mitigation at High Abstraction Levels

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    Radiation-induced soft errors, as one of the major reliability challenges in future technology nodes, have to be carefully taken into consideration in the design space exploration. This thesis presents several novel and efficient techniques for soft error evaluation and mitigation at high abstract levels, i.e. from register transfer level up to behavioral algorithmic level. The effectiveness of proposed techniques is demonstrated with extensive synthesis experiments

    Theories and Models for Internet Quality of Service

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    We survey recent advances in theories and models for Internet Quality of Service (QoS). We start with the theory of network calculus, which lays the foundation for support of deterministic performance guarantees in networks, and illustrate its applications to integrated services, differentiated services, and streaming media playback delays. We also present mechanisms and architecture for scalable support of guaranteed services in the Internet, based on the concept of a stateless core. Methods for scalable control operations are also briefly discussed. We then turn our attention to statistical performance guarantees, and describe several new probabilistic results that can be used for a statistical dimensioning of differentiated services. Lastly, we review recent proposals and results in supporting performance guarantees in a best effort context. These include models for elastic throughput guarantees based on TCP performance modeling, techniques for some quality of service differentiation without access control, and methods that allow an application to control the performance it receives, in the absence of network support

    Congestion and admission control in WDM optical networks

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    The demand for more communication bandwidth and network resources, has pushed researchers to find faster and more reliable data communication networks. Wavelength division multiplexing (WDM) is a promising technology to meet such increasing demands. To make use of the WDM networks, some issues need to be dealt with. This thesis discusses three problems, constraint-based path selection. Congestion Control and Admission Control. When selecting a path between the source and destination, in which some constraints are present, the choice of the path can have dramatic effects on the Quality of Service (QoS). Three path selection algorithms are compared in order to achieve optimum path selection. These algorithms are presented and analyzed in this thesis. The algorithms do not just deal with one path selection constraint but k-constraints. Two controllers are presented: A proposed congestion controller and the second is a call admission controller in circuit switched networks. The proposed congestion control algorithm is based on the fuzzy logic technique and aims to control the congestion in a WDM network through an adequate adjustment of the delay on the calls that are in the queue of the server. The adaptive admission controller for circuit switched networks is based on the optimization of resources in the network. Numerous Simulation results are presented which show the performance of each controller

    Data validation and reliability calculations in digital protection systems

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