32 research outputs found

    Time evolution of damage under variable ranges of load transfer

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    We study the time evolution of damage in a fiber bundle model in which the range of interaction of fibers varies through an adjustable stress transfer function recently introduced. We find that the lifetime of the material exhibits a crossover from mean field to short range behavior as in the static case. Numerical calculations showed that the value at which the transition takes place depends on the system's disorder. Finally, we have performed a microscopic analysis of the failure process. Our results confirm that the growth dynamics of the largest crack is radically different in the two limiting regimes of load transfer during the first stages of breaking.Comment: 8 pages, 7 figures, revtex4 styl

    Markets in Higher Education. Rhetoric or Reality?

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    On-chip COMA cache-coherence protocol for microgrids of microthreaded cores

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    This paper describes an on-chip COMA cache coherency protocol to support the microthread model of concurrent program composition. The model gives a sound basis for building multi-core computers as it captures concurrency, abstracts communication and identifies resources, such as processor groups explicitly and where mapping and scheduling is performed dynamically. The result is a model where binary compatibility is guaranteed over arbitrary numbers of cores and where backward binary compatibility is also assured. We present the design of a memory system with relaxed synchronisation and consistency constraints that matches the characteristics of this model. We exploit an on-chip COMA organisation, which provides a flexible and transparent partitioning between processors and memory. This paper describes the coherency protocol and consistency model and describes work undertaken on the validation of the model and the development of a co-simulator to the Microgrid CMP emulator.
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