4,323 research outputs found

    D2D Data Offloading in Vehicular Environments with Optimal Delivery Time Selection

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    Within the framework of a Device-to-Device (D2D) data offloading system for cellular networks, we propose a Content Delivery Management System (CDMS) in which the instant for transmitting a content to a requesting node, through a D2D communication, is selected to minimize the energy consumption required for transmission. The proposed system is particularly fit to highly dynamic scenarios, such as vehicular networks, where the network topology changes at a rate which is comparable with the order of magnitude of the delay tolerance. We present an analytical framework able to predict the system performance, in terms of energy consumption, using tools from the theory of point processes, validating it through simulations, and provide a thorough performance evaluation of the proposed CDMS, in terms of energy consumption and spectrum use. Our performance analysis compares the energy consumption and spectrum use obtained with the proposed scheme with the performance of two benchmark systems. The first one is a plain classic cellular scheme, the second is a D2D data offloading scheme (that we proposed in previous works) in which the D2D transmissions are performed as soon as there is a device with the required content within the maximum D2D transmission range..

    Nucleon Spin Structure with hadronic collisions at COMPASS

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    In order to illustrate the capabilities of COMPASS using a hadronic beam, I review some of the azimuthal asymmetries in hadronic collisions, that allow for the extraction of transversity, Sivers and Boer-Mulders functions, necessary to explore the partonic spin structure of the nucleon. I also report on some Monte Carlo simulations of such asymmetries for the production of Drell-Yan lepton pairs from the collision of high-energy pions on a transversely polarized proton target.Comment: talk delivered to the "International Workshop on Structure and Spectroscopy", Freiburg, March 19-21, 2007; 18 pages, RevTeX4 style, 8 figures with 10 .eps file

    Big image of Galois representations associated with finite slope pp-adic families of modular forms

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    We consider the Galois representation associated with a finite slope pp-adic family of modular forms. We prove that the Lie algebra of its image contains a congruence Lie subalgebra of a non-trivial level. We describe the largest such level in terms of the congruences of the family with pp-adic CM forms.Comment: 23 pages; revision of Section 2 (see Remark 2.4) and improvement of Proposition 4.14, plus minor changes. Published in "Elliptic Curves, Modular Forms and Iwasawa Theory. In Honour of John H. Coates' 70th Birthday, Cambridge, UK, March 2015", Springer Proceedings in Mathematics & Statistics, Vol. 188, 201

    Popularity

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    What makes you popular among your high-school peers? And what are the labor market returns to popularity? We investigate these questions using an objective measure of popularity derived from sociometric theory: the number of friendship nom- inations received from schoolmates. We provide novel evidence that early family en- vironment, school composition and school size play a signicant role in determining popularity. We show that the estimated wage return to one additional nomination is about 2 percent the popularity premium. This amounts to roughly 40 percent of the return to one more year of education. A revised version of this paper is published in the Fall 2013 issue of the Journal of Human Resources

    Time-resolved dynamics of granular matter by random laser emission

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    Because of the huge commercial importance of granular systems, the second-most used material in industry after water, intersecting the industry in multiple trades, like pharmacy and agriculture, fundamental research on grain-like materials has received an increasing amount of attention in the last decades. In photonics, the applications of granular materials have been only marginally investigated. We report the first phase-diagram of a granular as obtained by laser emission. The dynamics of vertically-oscillated granular in a liquid solution in a three-dimensional container is investigated by employing its random laser emission. The granular motion is function of the frequency and amplitude of the mechanical solicitation, we show how the laser emission allows to distinguish two phases in the granular and analyze its spectral distribution. This constitutes a fundamental step in the field of granulars and gives a clear evidence of the possible control on light-matter interaction achievable in grain-like system.Comment: 16 pages, 7 figure
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