Chaos is a similar and random process which is very sensitive to initial value in deterministic system. It is a performance of nonlinear dynamical system with built-in randomness. Combined with the advantages and disa...
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Chaos is a similar and random process which is very sensitive to initial value in deterministic system. It is a performance of nonlinear dynamical system with built-in randomness. Combined with the advantages and disadvantages of the present chaos encryption model, the paper proposes a chaotic stream cipher model based on chaos theory, which not only overcomes finite precision effect, but also improves the randomness of chaotic system and output sequence. The Sequence cycle theory generated by the algorithm can reach more than 10600 at least, which completely satisfies the actual application requirements of stream cipher system.
Existing OpenMP cost models does not give enough thought to the implementation details of OpenMP programs so they cannot be applied widely to different types of parallel loops. To solve this problem, this study extend...
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Fuzz testing is an automated black-box testing technique providing random data as input to a software system in the hope to find vulnerability. In order to be effective, the fuzzed input must be common enough to pass ...
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In order to achieve higher estimation accuracy of the embedding change rate of a stego object, an ensemble learning-based estimation method is presented. First of all, a framework of embedding change rate estimation b...
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While multicore processors increase throughput for multi-programmed and multithreaded codes, many important applications are single threaded and thus do not benefit. Automatic parallelization techniques play an import...
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ISBN:
(纸本)9781479914449
While multicore processors increase throughput for multi-programmed and multithreaded codes, many important applications are single threaded and thus do not benefit. Automatic parallelization techniques play an important role in migrating singe threaded applications to multicore platforms. Unfortunately, the prevalence of control flow, recursive data structures, and general pointer accesses in ordinary programs renders the traditional automatic parallelization techniques unsuitable. Parallel-Stage Decoupled Software Pipelining (PS-DSWP) is proposed to exploit fine-grained pipeline parallelism lurking in ordinary programs with the existence of all kinds of dependences, including arbitrary control dependences, at the instruction level. But it requires knowledge of architectural properties and hardware support of a communication channel and two special instructions. We propose an improved PS-DSWP algorithm based on OpenMP in this paper. It is implemented without relying on CPU architectures by using a high level intermediate representation. Moreover, the Program Dependence Graph (PDG) used in the algorithm is built based on the basic blocks, which exploits coarser-grained parallelism than the original PS-DSWP transformation with PDG based on instructions. OpenMP is employed in our algorithm to assign task and implement synchronization among threads while avoiding dependence on hardware support. We evaluate the loops with complex memory patterns and control flow, which cannot be dealt with by traditional techniques, on multicore platform. As a result, they can be parallelized and gain significant performance improvement with our algorithm. We obtain a maximum speedup as high as 2.07x and on average 1.39x with 5 threads.
When implementing SPMD programs on multi core platforms, whole function vectorization is an important optimization method. SPMD program has drawback that lots of instructions across multi threads are redundant which i...
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When implementing SPMD programs on multi core platforms, whole function vectorization is an important optimization method. SPMD program has drawback that lots of instructions across multi threads are redundant which is sustained in vectorization. This paper proposes to alleviate this overhead by detecting scalar operations and extract them out in vectorization instructions. An algorithm is designed to deal with control flow and data flow synchronously in which convergent and invariance analysis is employed to statically identify convergent execution and invariant values or instructions. Our algorithm is effectively on implementing SPMD programs on multi core platforms. The experiments show our method could improve the execution efficiency by 13.3%.
Integrating a large number of simple cores on the chip to provide the desired performance and throughput, microprocessor has entered the many core era. In order to fully extract the ability of the many core processor,...
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ISBN:
(纸本)9781479952465
Integrating a large number of simple cores on the chip to provide the desired performance and throughput, microprocessor has entered the many core era. In order to fully extract the ability of the many core processor, we propose speedup models for many core architecture in this paper. Under the assumption of Hill-Marty model, we deduce our formulas based on Gustafson's Law and Sun-Ni's Law. Then, compared with the Hill-Marty model, we theoretically analyze the best allocation under the given resources. Furthermore, we apply the conclusions of our models to evaluate current many core processors and predict concrete future architecture. Our results show that the many core architecture is capable of extensive scalability and being beneficial to promote the performance, especially heterogeneous one. By using simple analytical models, we provide a better understanding of architecture design and our work complement existing studies.
Traditional multicast protocol forms multicast trees rooted at different sources to forward packets. If the multicast sources and receivers are in different domains, these trees will produce a great number of multicas...
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Traditional multicast protocol forms multicast trees rooted at different sources to forward packets. If the multicast sources and receivers are in different domains, these trees will produce a great number of multicast states in the backbone, resulting in poor scalability. Therefore, we propose a one Wide-Sense Circuit Tree per Traffic Class based inter-domain multicast (WSCT-TC), in which a Wide-Sense Circuit Tree (WSCT) is established for a class of multicast traffic. The WSCT is established in the backbone, along which multicast packets are forwarded by label switching. The spec of WSCT can be reconfigured according to the QoS (Quality of Service) requirement of multicast applications, to provide preferable QoS. Simulating experiment shows that WSCT-TC behaves better scalability.
Measurements of ZZ production in the ℓ+ℓ−ℓ′+ℓ′− channel in proton–proton collisions at 13 TeV center-of-mass energy at the Large Hadron Collider are presented. The data correspond to 36.1 fb−1 of collisions collec...
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Measurements of ZZ production in the ℓ+ℓ−ℓ′+ℓ′− channel in proton–proton collisions at 13 TeV center-of-mass energy at the Large Hadron Collider are presented. The data correspond to 36.1 fb−1 of collisions collected by the ATLAS experiment in 2015 and 2016. Here ℓ and ℓ′ stand for electrons or muons. Integrated and differential ZZ→ℓ+ℓ−ℓ′+ℓ′− cross sections with Z→ℓ+ℓ− candidate masses in the range of 66 GeV to 116 GeV are measured in a fiducial phase space corresponding to the detector acceptance and corrected for detector effects. The differential cross sections are presented in bins of twenty observables, including several that describe the jet activity. The integrated cross section is also extrapolated to a total phase space and to all standard model decays of Z bosons with mass between 66 GeV and 116 GeV, resulting in a value of 17.3±0.9[±0.6(stat)±0.5(syst)±0.6(lumi)] pb. The measurements are found to be in good agreement with the standard model. A search for neutral triple gauge couplings is performed using the transverse momentum distribution of the leading Z boson candidate. No evidence for such couplings is found and exclusion limits are set on their parameters.
For the first time, the γ decay of excited states has been observed in a nucleus situated in the quadrant south-east of doubly magic Sn132, a region in which experimental information so far is limited to ground-state...
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For the first time, the γ decay of excited states has been observed in a nucleus situated in the quadrant south-east of doubly magic Sn132, a region in which experimental information so far is limited to ground-state properties. Six γ rays with energies of 50, 86, 103, 227, 357, and 602 keV were observed following the β-delayed neutron emission from Cd85133, populated in the projectile fission of a U238 beam at the Radioactive Isotope Beam Factory at RIKEN within the EURICA project. The new experimental information is compared to the results of a modern realistic shell-model calculation, the first one in this region very far from stability, focusing in particular on the π0g9/2−1⊗ν1f7/2 particle-hole multiplet in In83132. In addition, theoretical estimates based on a scaling of the two-body matrix elements for the πh11/2−1⊗νg9/2 analog multiplet in Tl127208, one major proton and one major neutron shell above, are presented.
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