Properties of disjoint paths between a given source (S) and destination (D) in data manipulator networks are examined. The condition that must be present to have disjoint paths through the network for a given S and D ...
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Properties of disjoint paths between a given source (S) and destination (D) in data manipulator networks are examined. The condition that must be present to have disjoint paths through the network for a given S and D pair is presented. It is proven that the maximum number of disjoint paths for any S/D pair is two, and a method for finding the routing tags that specify these paths is given. The effect of a fault in a given stage of the network on the number of S/D pairs that can be connected is also discussed.< >
Mapping cyclic reduction, a known approach for the parallel solution of tridiagonal systems of equations, onto the MasPar MP-1, nCUBE 2, and PASM parallel machines is discussed. Each of these represents a different mo...
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Mapping cyclic reduction, a known approach for the parallel solution of tridiagonal systems of equations, onto the MasPar MP-1, nCUBE 2, and PASM parallel machines is discussed. Each of these represents a different mode of parallelism. Issues addressed are SIMD/MIMD trade-offs, the effect on execution time of increasing the number of processors used, the impact of the inter-processor communications network on performance, the importance of predicting algorithm performance as a function of the mapping used, and the advantages of a partitionable system. Analytical results are validated by experimentation on all three machines.< >
It is suggested that, while high-level-language and OS abstractions have evolved gradually and intelligently over the years with respect to single-instruction, single-data stream machines, these abstractions should no...
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It is suggested that, while high-level-language and OS abstractions have evolved gradually and intelligently over the years with respect to single-instruction, single-data stream machines, these abstractions should not necessarily be provided in early generations of parallel supercomputers. Experience with low-level programming must precede the definition and evolution of abstractions for such machines. Future systems will naturally evolve to the correct level of abstraction, but experimentation with current machines must proceed as much as possible at levels that allow direct examination and evaluation of machine characteristics. Further, new software and hardware techniques should be developed to provide services that will be necessary, such as secure access to multiuser devices.< >
A technique for architectural evaluation that has been used with good results and that is applicable to most experimental and commercial machines is proposed. This technique is that of careful experimentation on a bar...
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A technique for architectural evaluation that has been used with good results and that is applicable to most experimental and commercial machines is proposed. This technique is that of careful experimentation on a bare system, i.e. one without a resident kernel, operating system, or high-level language support. The experimentation involves the implementation of simple algorithms designed to utilize the basic features of the architecture and exploit its unique features. This technique makes possible the analysis of an architecture without the complexities introduced by most operating systems and compilers and can yield insight beneficial in future language, compiler, operating system, application, and system design. Hybrid SIMD/MIMD architectures are considered as an example.< >
Features of an explicitly parallel language targeted for reconfigurable massively parallelprocessing systems capable of operating in the SIMD (single-instruction-stream, multiple-data-stream) and SPMD (single-program...
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Features of an explicitly parallel language targeted for reconfigurable massively parallelprocessing systems capable of operating in the SIMD (single-instruction-stream, multiple-data-stream) and SPMD (single-program, multiple-data-stream) modes of parallelism are presented (SPMD is a subset of MIMD (multiple-instruction stream, multiple-data stream)). All aspects of the language have been provided with an SIMD-mode version and an SPMD-mode version that are functionally equivalent. The language facilitates experimentation with and exploitation of massively parallel SIMD/SPMD machines. Aspects of data management (variable specification, data manipulation operations, etc.) and control-flow constructs (data dependent and processor address dependent) are examined.< >
The excellent remote sensing ability of synthetic aperture radar(SAR)will be misled seriously when it encounters deceptive jamming which possesses high fidelity and *** this paper,the dynamic synthetic aperture(DSA)sc...
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The excellent remote sensing ability of synthetic aperture radar(SAR)will be misled seriously when it encounters deceptive jamming which possesses high fidelity and *** this paper,the dynamic synthetic aperture(DSA)scheme is used to extract the difference between the true and false targets.A simultaneous deceptive jamming suppression and target reconstruction method is proposed for a single channel SAR system to guarantee remote sensing *** system model is formulated as a sparse signal recovery problem with an unknown parametric dictionary to be *** iterative reweighted method is employed to jointly handle the dictionary parameter learning and target reconstruction problem in an majorization-minimization framework,where a surrogate function majorizing the Gaussian entropy in the objective function is introduced to circumvent its *** dictionary parameter learning,the grid mismatching problem in a fixed grid based method is ***,the proposed method can reap a super resolution ***,a simple yet effective DSA section scheme is developed for the SAR data excerpting,in which only two DSAs are *** results about location error and reconstruction power error reveal that the proposed method is able to achieve a good performance in deceptive jamming suppression.
This paper proposes a two-step general framework for reversible data hiding(RDH)schemes with controllable contrast *** first step aims at preserving visual perception as much as possible on the basis of achieving high...
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This paper proposes a two-step general framework for reversible data hiding(RDH)schemes with controllable contrast *** first step aims at preserving visual perception as much as possible on the basis of achieving high embedding capacity(EC),while the second step is used for increasing image *** the second step,some peak-pairs are utilized so that the histogram of pixel values is modified to perform histogram equalization(HE),which would lead to the image contrast ***,for HE,the utilization of some peak-pairs easily leads to over-enhanced image contrast when a large number of bits are ***,in our proposed framework,contrast over-enhancement is avoided by controlling the degree of contrast *** the second step can only provide a small amount of data due to controlled contrast enhancement,the first one helps to achieve a large amount of data without degrading visual *** RDH method which can achieve high EC while preserve good visual quality,can be selected for the first *** fact,Gao et al.’s method is a special case of our proposed *** addition,two simple and commonly-used RDH methods are also introduced to further demonstrate the generalization of our framework.
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