16,292 research outputs found

    Unique intermetallic compounds prepared by shock wave synthesis

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    Technique compresses fine ground metallic powder mixture beyond crystal fusion point. Absence of vapor pressure voids and elimination of incongruous effects permit application of technique to large scale fabrication of intermetallic compounds with specific characteristics, e.g., semiconduction, superconduction, or magnetic properties

    Bits Through Bufferless Queues

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    This paper investigates the capacity of a channel in which information is conveyed by the timing of consecutive packets passing through a queue with independent and identically distributed service times. Such timing channels are commonly studied under the assumption of a work-conserving queue. In contrast, this paper studies the case of a bufferless queue that drops arriving packets while a packet is in service. Under this bufferless model, the paper provides upper bounds on the capacity of timing channels and establishes achievable rates for the case of bufferless M/M/1 and M/G/1 queues. In particular, it is shown that a bufferless M/M/1 queue at worst suffers less than 10% reduction in capacity when compared to an M/M/1 work-conserving queue.Comment: 8 pages, 3 figures, accepted in 51st Annual Allerton Conference on Communication, Control, and Computing, University of Illinois, Monticello, Illinois, Oct 2-4, 201

    Understanding the Fano Resonance : through Toy Models

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    The Fano Resonance, involving the mixing between a quasi-bound `discrete' state of an inelastic channel lying in the continuum of scattering states belonging to the elastic channel, has several subtle features. The underlying ideas have recently attracted attention in connection with interference effects in quantum wires and mesoscopic transport phenomena. Simple toy models are provided in the present study to illustrate the basics of the Fano resonance in a simple and tractable setting.Comment: 17 pages, 1 figur

    EACOF: A Framework for Providing Energy Transparency to enable Energy-Aware Software Development

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    Making energy consumption data accessible to software developers is an essential step towards energy efficient software engineering. The presence of various different, bespoke and incompatible, methods of instrumentation to obtain energy readings is currently limiting the widespread use of energy data in software development. This paper presents EACOF, a modular Energy-Aware Computing Framework that provides a layer of abstraction between sources of energy data and the applications that exploit them. EACOF replaces platform specific instrumentation through two APIs - one accepts input to the framework while the other provides access to application software. This allows developers to profile their code for energy consumption in an easy and portable manner using simple API calls. We outline the design of our framework and provide details of the API functionality. In a use case, where we investigate the impact of data bit width on the energy consumption of various sorting algorithms, we demonstrate that the data obtained using EACOF provides interesting, sometimes counter-intuitive, insights. All the code is available online under an open source license. http://github.com/eaco

    CORRELATION OF CERTAIN ATTITUDES WITH PERSONALITY TRAITS

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    Purpose.--The purpose of this study is to determine how much, if any, relationship exists between certain attitudes in individuals and their composite percentile scores in intelligence tests, and certain traits in personality in a group of ninety-eight college freshmen at the Kansas State Teachers College of Pittsburg, Kansas. Procedure.--The Pearson formula for determining the coefficient of correlation was used and correlations made on all the data obtained from testing forty-three freshmen men and fifty-five freshmen women. That is, attitudes toward the church, toward communism, and toward birth control were correlated with each of the personality traits of neuroticism, introversion-extroversion, self-sufficiency, and dominance-submission, and also with the intelligence test results. Findings.--The main findings of this study were: (1) There was not a single high correlation, as correlations go, and none that meets the statistical demands for significance, (2) The results seem to agree with similar studies that have been made

    Regular and Singular Pulse and Front Solutions and Possible Isochronous Behavior in the Short-Pulse Equation: Phase-Plane, Multi-Infinite Series and Variational Approaches

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    In this paper we employ three recent analytical approaches to investigate the possible classes of traveling wave solutions of some members of a family of so-called short-pulse equations (SPE). A recent, novel application of phase-plane analysis is first employed to show the existence of breaking kink wave solutions in certain parameter regimes. Secondly, smooth traveling waves are derived using a recent technique to derive convergent multi-infinite series solutions for the homoclinic (heteroclinic) orbits of the traveling-wave equations for the SPE equation, as well as for its generalized version with arbitrary coefficients. These correspond to pulse (kink or shock) solutions respectively of the original PDEs. Unlike the majority of unaccelerated convergent series, high accuracy is attained with relatively few terms. And finally, variational methods are employed to generate families of both regular and embedded solitary wave solutions for the SPE PDE. The technique for obtaining the embedded solitons incorporates several recent generalizations of the usual variational technique and it is thus topical in itself. One unusual feature of the solitary waves derived here is that we are able to obtain them in analytical form (within the assumed ansatz for the trial functions). Thus, a direct error analysis is performed, showing the accuracy of the resulting solitary waves. Given the importance of solitary wave solutions in wave dynamics and information propagation in nonlinear PDEs, as well as the fact that not much is known about solutions of the family of generalized SPE equations considered here, the results obtained are both new and timely.Comment: accepted for publication in Communications in Nonlinear Science and Numerical Simulatio

    Impact of Rural-urban Labour Migration on Education of Children: A Case Study of Left behind and Accompanied Migrant Children in India

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    In developing countries, seasonal labour migration from rural to urban or from backward to developed region is a household livelihood strategy to cope with poverty. In this process, the children of those migrants are the worst affected whether they accompany their parents or are left behind in the villages. The present paper explores the impact of temporary labour migration of parent(s) on school attendance of the children between 6–14 years and their dropping out from the school through an analysis of the cases from both the ends of migration stream in India. Data was collected from thirteen construction sites of Varanasi Uttar Pradesh and nine villages of Bihar by applying both qualitative and quantitative techniques. It is evident from the study that the migrants through remittances improve school accessibility for the left behind children and bridge gender gap in primary school education. However, among the accompanying migrant children of construction workers, many remain out of school and many are forced to drop out and some of them become vulnerable to work as child labour due to seasonal mobility of their parents. Thus, mainstreaming these children in development process is a big challenge in attaining the goal of universal primary education and inclusive growth in the country like India

    Phases, many-body entropy measures and coherence of interacting bosons in optical lattices

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    Already a few bosons with contact interparticle interactions in small optical lattices feature a variety of quantum phases: superfluid, Mott-insulator and fermionized Tonks gases can be probed in such systems. To detect these phases -- pivotal for both experiment and theory -- as well as their many-body properties we analyze several distinct measures for the one-body and many-body Shannon information entropies. We exemplify the connection of these entropies with spatial correlations in the many-body state by contrasting them to the Glauber normalized correlation functions. To obtain the ground-state for lattices with commensurate filling (i.e. an integer number of particles per site) for the full range of repulsive interparticle interactions we utilize the multiconfigurational time-dependent Hartree method for bosons (MCTDHB) in order to solve the many-boson Schr\"odinger equation. We demonstrate that all emergent phases -- the superfluid, the Mott insulator, and the fermionized gas can be characterized equivalently by our many-body entropy measures and by Glauber's normalized correlation functions. In contrast to our many-body entropy measures, single-particle entropy cannot capture these transitions.Comment: 11 pages, 7 figures, software available at http://ultracold.or
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