3,673 research outputs found

    Intangible trust requirements - how to fill the requirements trust "gap"?

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    Previous research efforts have been expended in terms of the capture and subsequent instantiation of "soft" trust requirements that relate to HCI usability concerns or in relation to "hard" tangible security requirements that primarily relate to security a ssurance and security protocols. Little direct focus has been paid to managing intangible trust related requirements per se. This 'gap' is perhaps most evident in the public B2C (Business to Consumer) E- Systems we all use on a daily basis. Some speculative suggestions are made as to how to fill the 'gap'. Visual card sorting is suggested as a suitable evaluative tool; whilst deontic logic trust norms and UML extended notation are the suggested (methodologically invariant) means by which software development teams can perhaps more fully capture hence visualize intangible trust requirements

    Making the Most of Your Samples

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    We study the problem of setting a price for a potential buyer with a valuation drawn from an unknown distribution DD. The seller has "data"' about DD in the form of m≥1m \ge 1 i.i.d. samples, and the algorithmic challenge is to use these samples to obtain expected revenue as close as possible to what could be achieved with advance knowledge of DD. Our first set of results quantifies the number of samples mm that are necessary and sufficient to obtain a (1−ϵ)(1-\epsilon)-approximation. For example, for an unknown distribution that satisfies the monotone hazard rate (MHR) condition, we prove that Θ~(ϵ−3/2)\tilde{\Theta}(\epsilon^{-3/2}) samples are necessary and sufficient. Remarkably, this is fewer samples than is necessary to accurately estimate the expected revenue obtained by even a single reserve price. We also prove essentially tight sample complexity bounds for regular distributions, bounded-support distributions, and a wide class of irregular distributions. Our lower bound approach borrows tools from differential privacy and information theory, and we believe it could find further applications in auction theory. Our second set of results considers the single-sample case. For regular distributions, we prove that no pricing strategy is better than 12\tfrac{1}{2}-approximate, and this is optimal by the Bulow-Klemperer theorem. For MHR distributions, we show how to do better: we give a simple pricing strategy that guarantees expected revenue at least 0.5890.589 times the maximum possible. We also prove that no pricing strategy achieves an approximation guarantee better than e4≈.68\frac{e}{4} \approx .68

    Collisions of Jets of Particles from Active Galactic Nuclei with Neutralino Dark Matter

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    We examine the possibility that energetic Standard Model particles contained in the jets produced by active galactic nuclei (AGN) may scatter off of the dark matter halo which is expected to surround the AGN. In particular, if there are nearby states in the dark sector which can appear resonantly in the scattering, the cross section can be enhanced and a distinctive edge feature in the energy spectrum may appear. We examine bounds on supersymmetric models which may be obtained from the Fermi Gamma-ray Space Telescope observation of the nearby AGN Centaurus A.Comment: 20 pages, 9 figures; v2: version published in JCA

    Can intelligent optimisation techniques improve computing job scheduling in a Grid environment? review, problem and proposal

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    In the existing Grid scheduling literature, the reported methods and strategies are mostly related to high-level schedulers such as global schedulers, external schedulers, data schedulers, and cluster schedulers. Although a number of these have previously considered job scheduling, thus far only relatively simple queue-based policies such as First In First Out (FIFO) have been considered for local job scheduling within Grid contexts. Our initial research shows that it is worth investigating the potential impact on the performance of the Grid when intelligent optimisation techniques are applied to local scheduling policies. The research problem is defined, and a basic research methodology with a detailed roadmap is presented. This paper forms a proposal with the intention of exchanging ideas and seeking potential collaborators

    Reflection on Kurosawa Akira’s Movies

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    This senior project is a reflection of Kurosawa Akira’s movies. I discussed the film techniques he used and his cultural confidence. In addition, I talked about the connection between his movies and my adaption of Spring Bird

    Private Matchings and Allocations

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    We consider a private variant of the classical allocation problem: given k goods and n agents with individual, private valuation functions over bundles of goods, how can we partition the goods amongst the agents to maximize social welfare? An important special case is when each agent desires at most one good, and specifies her (private) value for each good: in this case, the problem is exactly the maximum-weight matching problem in a bipartite graph. Private matching and allocation problems have not been considered in the differential privacy literature, and for good reason: they are plainly impossible to solve under differential privacy. Informally, the allocation must match agents to their preferred goods in order to maximize social welfare, but this preference is exactly what agents wish to hide. Therefore, we consider the problem under the relaxed constraint of joint differential privacy: for any agent i, no coalition of agents excluding i should be able to learn about the valuation function of agent i. In this setting, the full allocation is no longer published---instead, each agent is told what good to get. We first show that with a small number of identical copies of each good, it is possible to efficiently and accurately solve the maximum weight matching problem while guaranteeing joint differential privacy. We then consider the more general allocation problem, when bidder valuations satisfy the gross substitutes condition. Finally, we prove that the allocation problem cannot be solved to non-trivial accuracy under joint differential privacy without requiring multiple copies of each type of good.Comment: Journal version published in SIAM Journal on Computation; an extended abstract appeared in STOC 201

    Development and characterization of a laser-induced acoustic desorption source

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    A laser-induced acoustic desorption source, developed for use at central facilities, such as free-electron lasers, is presented. It features prolonged measurement times and a fixed interaction point. A novel sample deposition method using aerosol spraying provides a uniform sample coverage and hence stable signal intensity. Utilizing strong-field ionization as a universal detection scheme, the produced molecular plume is characterized in terms of number density, spatial extend, fragmentation, temporal distribution, translational velocity, and translational temperature. The effect of desorption laser intensity on these plume properties is evaluated. While translational velocity is invariant for different desorption laser intensities, pointing to a non-thermal desorption mechanism, the translational temperature increases significantly and higher fragmentation is observed with increased desorption laser fluence.Comment: 8 pages, 7 figure

    Six Top Messages of New Physics at the LHC

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    Six top signatures provide a novel probe of new physics. We discuss production of six top quarks as the decay products of a pair of top partners in the setting of a composite Higgs model, and argue that the six top signal may generically provide one of the first final states to show a discrepancy. We construct an analysis based on quantities such as HTH_T and the numbers of jets which are tagged as boosted tops, WWs, or containing bb-tags, and show that the LHC with 3~ab−1^{-1} can discover top partners with masses up to around 2.5 TeV in the six top signature.Comment: 15 pages, 6 figures, and 2 table

    On base sizes for primitive groups of product type

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