44,189 research outputs found

    Sufficient conditions for unique global solutions in optimal control of semilinear equations with C1C^1-nonlinearity

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    We consider a C1C^1-semilinear elliptic optimal control problem possibly subject to control and/or state constraints. Generalizing previous work we provide a condition which guarantees that a solution of the necessary first order conditions is a global minimum. A similiar result also holds at the discrete level where the corresponding condition can be evaluated explicitly. Our investigations are motivated by G\"unter Leugering, who raised the question whether our previous results can be extended to the nonlinearity ϕ(s)=ss\phi(s)=s|s|. We develop a corresponding analysis and present several numerical test examples demonstrating its usefulness in practice

    Throughput Scaling Laws for Wireless Networks with Fading Channels

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    A network of n communication links, operating over a shared wireless channel, is considered. Fading is assumed to be the dominant factor affecting the strength of the channels between transmitter and receiver terminals. It is assumed that each link can be active and transmit with a constant power P or remain silent. The objective is to maximize the throughput over the selection of active links. By deriving an upper bound and a lower bound, it is shown that in the case of Rayleigh fading (i) the maximum throughput scales like logn\log n (ii) the maximum throughput is achievable in a distributed fashion. The upper bound is obtained using probabilistic methods, where the key point is to upper bound the throughput of any random set of active links by a chi-squared random variable. To obtain the lower bound, a decentralized link activation strategy is proposed and analyzed.Comment: Submitted to IEEE Transactions on Information Theory (Revised

    Squeezed States and Hermite polynomials in a Complex Variable

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    Following the lines of the recent paper of J.-P. Gazeau and F. H. Szafraniec [J. Phys. A: Math. Theor. 44, 495201 (2011)], we construct here three types of coherent states, related to the Hermite polynomials in a complex variable which are orthogonal with respect to a non-rotationally invariant measure. We investigate relations between these coherent states and obtain the relationship between them and the squeezed states of quantum optics. We also obtain a second realization of the canonical coherent states in the Bargmann space of analytic functions, in terms of a squeezed basis. All this is done in the flavor of the classical approach of V. Bargmann [Commun. Pur. Appl. Math. 14, 187 (1961)].Comment: 15 page

    O(αs)O(\alpha_s) Corrections to BXse+eB \to X_s e^+ e^- Decay in the 2HDM

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    O(αs)O(\alpha_s) QCD corrections to the inclusive BXse+eB \to X_s e^+ e^- decay are investigated within the two - Higgs doublet extension of the standard model (2HDM). The analysis is performed in the so - called off-resonance region; the dependence of the obtained results on the choice of the renormalization scale is examined in details. It is shown that O(αs)O(\alpha_s) corrections can suppress the BXse+eB \to X_s e^+ e^- decay width up to 1.5÷31.5 \div 3 times (depending on the choice of the dilepton invariant mass ss and the low - energy scale μ\mu). As a result, in the experimentally allowed range of the parameters space, the relations between the BXse+eB \to X_s e^+ e^- branching ratio and the new physics parameters are strongly affected. It is found also that though the renormalization scale dependence of the BXse+eB \to X_s e^+ e^- branching is significantly reduced, higher order effects in the perturbation theory can still be nonnegligible.Comment: 16 pages, latex, including 6 figures and 3 table
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