3,144 research outputs found

    Reversing conditional orderings

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    We analyze some specific aspects concerning conditional orderings and relations among them. To this purpose we define a suitable concept of reversed conditional ordering and prove some related results. In particular we aim to compare the univariate stochastic orderings ≤ st, ≤ hr, and ≤ lr in terms of differences among different notions of conditional orderings. Some applications of our result to the analysis of positive dependence will be detailed. We concentrate attention to the case of a pair of scalar random variables X, Y ​. Suitable extensions to multivariate cases are possible

    The decreasing percentile residual life aging notion

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    Earlier researchers have studied some aspects of the classes of distribution functions with decreasing ?-percentile residual life (DPRL(?)), 0Reliability theory, Hazard rate, Stochastic orders, Aging notions, Nonparametric estimation, Strongly uniform consistency

    On the Stereochemistry of the Cations in the Doping Block of Superconducting Copper-Oxides

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    Metal-oxygen complexes containing Cu,- Tl-, Hg-, Bi- and Pb-cations are electronically active in superconducting copper-oxides by stabilizing single phases with enhanced TcT_c, whereas other metal-oxygen complexes deteriorate copper-oxide superconductivity. Cu, Tl, Hg, Bi, Pb in their actual oxidation states are closed shell d10d^{10} or inert s2s^2 pair ions. Their electronic configurations have a strong tendency to polarize the oxygen environment. The closed shell dd ions with low lying nd10nd9(n+1)snd^{10}\leftrightarrow nd^9(n+1)s excitations form linear complexes through dz2sd_{z^2}-s hybridization polarizing the apical oxygens. Comparatively low nd9(n+1)snd^9(n+1)s excitation energies distinguish Cu1+,3+,Tl3+,Hg2+\rm Cu^{1+,3+}, Tl^{3+}, Hg^{2+} from other closed shell d10d^{10} ions deteriorating copper-oxide superconductivity, {\it e.g.} Zn2+\rm Zn^{2+}.Comment: 5 pages, uses REVTEX. To be published in: J. Superconductivity, Proc. Int. Workshop on "Phase Separation, Electronic Inhomogenities and Related Mechanisms for High T_c Superconductors", Erice (Sicily) 9-15 July 199

    Stochastic comparisons of nonhomogeneous processes

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    The purpose of this paper is to describe various conditions on the parameters of pairs of nonhomogeneous Poisson or birth processes under which the corresponding epoch or inter-epoch times are stochastically ordered in various senses. We derive results involving the usual stochastic order, the multivariate hazard rate order, the multivariate likelihood ratio order, and the multivariate mean residual life order. A sample of applications involving generalized Yule processes, load-sharing models, and minimal repairs in reliability theory, illustrate the usefulness of the new results

    Security by Spatial Reference:Using Relative Positioning to Authenticate Devices for Spontaneous Interaction

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    Spontaneous interaction is a desirable characteristic associated with mobile and ubiquitous computing. The aim is to enable users to connect their personal devices with devices encountered in their environment in order to take advantage of interaction opportunities in accordance with their situation. However, it is difficult to secure spontaneous interaction as this requires authentication of the encountered device, in the absence of any prior knowledge of the device. In this paper we present a method for establishing and securing spontaneous interactions on the basis of emphspatial references that capture the spatial relationship of the involved devices. Spatial references are obtained by accurate sensing of relative device positions, presented to the user for initiation of interactions, and used in a peer authentication protocol that exploits a novel mechanism for message transfer over ultrasound to ensures spatial authenticity of the sender

    The Resistive-Plate WELL with Argon mixtures - a robust gaseous radiation detector

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    A thin single-element THGEM-based, Resistive-Plate WELL (RPWELL) detector was operated with 150 GeV/c muon and pion beams in Ne/(5%CH4_4), Ar/(5%CH4_4) and Ar/(7%CO2_2); signals were recorded with 1 cm2^2 square pads and SRS/APV25 electronics. Detection efficiency values greater than 98% were reached in all the gas mixtures, at average pad multiplicity of 1.2. The use of the 109^9{\Omega}cm resistive plate resulted in a completely discharge-free operation also in intense pion beams. The efficiency remained essentially constant at 98-99% up to fluxes of \sim104^4Hz/cm2^2, dropping by a few % when approaching 105^5 Hz/cm2^2. These results pave the way towards cost-effective, robust, efficient, large-scale detectors for a variety of applications in future particle, astro-particle and applied fields. A potential target application is digital hadron calorimetry.Comment: presented at the 2016 VIenna Conf. On instrumentation. Submitted to the Conference proceeding

    Probabilistic Analysis of Facility Location on Random Shortest Path Metrics

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    The facility location problem is an NP-hard optimization problem. Therefore, approximation algorithms are often used to solve large instances. Such algorithms often perform much better than worst-case analysis suggests. Therefore, probabilistic analysis is a widely used tool to analyze such algorithms. Most research on probabilistic analysis of NP-hard optimization problems involving metric spaces, such as the facility location problem, has been focused on Euclidean instances, and also instances with independent (random) edge lengths, which are non-metric, have been researched. We would like to extend this knowledge to other, more general, metrics. We investigate the facility location problem using random shortest path metrics. We analyze some probabilistic properties for a simple greedy heuristic which gives a solution to the facility location problem: opening the κ\kappa cheapest facilities (with κ\kappa only depending on the facility opening costs). If the facility opening costs are such that κ\kappa is not too large, then we show that this heuristic is asymptotically optimal. On the other hand, for large values of κ\kappa, the analysis becomes more difficult, and we provide a closed-form expression as upper bound for the expected approximation ratio. In the special case where all facility opening costs are equal this closed-form expression reduces to O(ln(n)4)O(\sqrt[4]{\ln(n)}) or O(1)O(1) or even 1+o(1)1+o(1) if the opening costs are sufficiently small.Comment: A preliminary version accepted to CiE 201
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