167 research outputs found

    A New Framework for Network Disruption

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    Traditional network disruption approaches focus on disconnecting or lengthening paths in the network. We present a new framework for network disruption that attempts to reroute flow through critical vertices via vertex deletion, under the assumption that this will render those vertices vulnerable to future attacks. We define the load on a critical vertex to be the number of paths in the network that must flow through the vertex. We present graph-theoretic and computational techniques to maximize this load, firstly by removing either a single vertex from the network, secondly by removing a subset of vertices.Comment: Submitted for peer review on September 13, 201

    An analytical error model for quantum computer simulation

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    Quantum computers (QCs) must implement quantum error correcting codes (QECCs) to protect their logical qubits from errors, and modeling the effectiveness of QECCs on QCs is an important problem for evaluating the QC architecture. The previously developed Monte Carlo (MC) error models may take days or weeks of execution to produce an accurate result due to their random sampling approach. We present an alternative analytical error model that generates, over the course of executing the quantum program, a probability tree of the QC's error states. By calculating the fidelity of the quantum program directly, this error model has the potential for enormous speedups over the MC model when applied to small yet useful problem sizes. We observe a speedup on the order of 1,000X when accuracy is required, and we evaluate the scaling properties of this new analytical error model

    On the methodological unification in electroencephalography

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    BACKGROUND: This paper presents results of a pursuit of a repeatable and objective methodology of analysis of the electroencephalographic (EEG) time series. METHODS: Adaptive time-frequency approximations of EEG are discussed in the light of the available experimental and theoretical evidence, and applicability in various experimental and clinical setups. RESULTS: Four lemmas and three conjectures support the following conclusion. CONCLUSION: Adaptive time-frequency approximations of signals unify most of the univariate computational approaches to EEG analysis, and offer compatibility with its traditional (visual) analysis, used in clinical applications

    Evaluating the Viability of 100 Per Cent Container Inspection at America’s Ports

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    As U.S. maritime security adapts to the terrorist threat, we argue that quantitative analysis should be used to evaluate security initiatives and present a case study of one proposed measure: 100 percent scanning of containers entering the United States. By assessing the minimum attack likelihood required to justify increased inspection costs, we conclude that 100 percent scanning is cost-effective only if the attack damages or likelihood of an attack are quite high. Even so, additional land and labor transaction costs could render adoption infeasible unless scanning technologies improve significantly

    Yaco: A user conducted visualization tool for supporting cache optimization

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    Abstract. To enhance the overall performance of an application it is necessary to improve the cache access behavior. In this case, a cache visualizer is usually needed for fully understanding the runtime cache activities and the access pattern of applications. However, it does not suffice if only visualizing what happened. More importantly, a visualizer has to provide users with the knowledge about the reason for cache misses and to illustrate how the cache behaves at the runtime. This is also the goal of YACO (Yet Another Cache-visualizer for Optimization). Different from existing tools, YACO uses a top-down approach to direct the user step-by-step to detect the problem and the solution.

    Applying Risk Assessment to Secure the Containerized Supply Chain

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    Over the past decades, container transport has been booming with an annual average growth of 9.3% increasing its modal share from 6.3% in 1980 to over 25% currently. The world’s largest container ports now handle over 20 million 20-ft-equivalent units (TEUs) per annum and have shown spectacular growth over the past years, with the main pivot of growth being the Far East. The global flow of containers represents the lifeblood of modern economies, without which we would not be able to enjoy the way of life that we have. This unfortunately is exactly one of the criteria terrorists are known to apply when selecting their targets, rendering the global containerized supply chain a potentially attractive target
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