45,363 research outputs found

    The Value-of-Information in Matching with Queues

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    We consider the problem of \emph{optimal matching with queues} in dynamic systems and investigate the value-of-information. In such systems, the operators match tasks and resources stored in queues, with the objective of maximizing the system utility of the matching reward profile, minus the average matching cost. This problem appears in many practical systems and the main challenges are the no-underflow constraints, and the lack of matching-reward information and system dynamics statistics. We develop two online matching algorithms: Learning-aided Reward optimAl Matching (LRAM\mathtt{LRAM}) and Dual-LRAM\mathtt{LRAM} (DRAM\mathtt{DRAM}) to effectively resolve both challenges. Both algorithms are equipped with a learning module for estimating the matching-reward information, while DRAM\mathtt{DRAM} incorporates an additional module for learning the system dynamics. We show that both algorithms achieve an O(ϡ+δr)O(\epsilon+\delta_r) close-to-optimal utility performance for any ϡ>0\epsilon>0, while DRAM\mathtt{DRAM} achieves a faster convergence speed and a better delay compared to LRAM\mathtt{LRAM}, i.e., O(δz/ϡ+log⁑(1/ϡ)2))O(\delta_{z}/\epsilon + \log(1/\epsilon)^2)) delay and O(δz/ϡ)O(\delta_z/\epsilon) convergence under DRAM\mathtt{DRAM} compared to O(1/ϡ)O(1/\epsilon) delay and convergence under LRAM\mathtt{LRAM} (δr\delta_r and δz\delta_z are maximum estimation errors for reward and system dynamics). Our results reveal that information of different system components can play very different roles in algorithm performance and provide a systematic way for designing joint learning-control algorithms for dynamic systems

    Convergence and Growth Linkages Between North and South

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    Using cross-sectional data for 98 countries for 1960-85, this paper shows that growth of per capita GDP depends negatively on initial income levels, as implied by the convergence hypothesis, as well as on international differences in investment rates in physical and human capital. There is some evidence of slight economies of scale (1.06) among the industrial countries. The evidence in favor of the convergence hypothesis is strongest for the countries of the OECD and Latin America, and weakest for Asia. Growth in Latin America and Africa is lower than elsewhere even after allowing for international differences in initial income levels, scale, schooling and capital investment. Analysis of Solow residuals for the OECD countries (for which capital stock data are available) shows convergence in rates of technical progress, suggesting that convergence of per capita GDPs is not Just a function of differences in investment rates. The linkage between per capita GDP and the real exchange rate is found to be strong for the OECD and Asia, weak for Africa and negative for Latin America.

    Generalized Bose-Fermi statistics and structural correlations in weighted networks

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    We derive a class of generalized statistics, unifying the Bose and Fermi ones, that describe any system where the first-occupation energies or probabilities are different from subsequent ones, as in presence of thresholds, saturation, or aging. The statistics completely describe the structural correlations of weighted networks, which turn out to be stronger than expected and to determine significant topological biases. Our results show that the null behavior of weighted networks is different from what previously believed, and that a systematic redefinition of weighted properties is necessary.Comment: Final version accepted for publication on Physical Review Letter

    Inverse Avalanches On Abelian Sandpiles

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    A simple and computationally efficient way of finding inverse avalanches for Abelian sandpiles, called the inverse particle addition operator, is presented. In addition, the method is shown to be optimal in the sense that it requires the minimum amount of computation among methods of the same kind. The method is also conceptually nice because avalanche and inverse avalanche are placed in the same footing.Comment: 5 pages with no figure IASSNS-HEP-94/7

    Anti-inflammatory cytokines in asthma and allergy: interleukin-10, interleukin-12, interferon-gamma.

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    Interleukin-10 (IL-10) is a cytokine derived from CD4+ T-helper type 2 (T(H2)) cells identified as a suppressor of cytokines from T-helper type 1(T(H1)) cells. Interleukin-12 (IL-12) is produced by B cells, macrophages and dendritic cells, and primarily regulates T(H1) cell differentiation, while suppressing the expansion of T(H2) cell clones. Interferon-gamma (IFN-gamma) is a product of T(H1) cells and exerts inhibitory effects on T(H2) cell differentiation. These cytokines have been implicated in the pathogenesis of asthma and allergies. In this context, IL-12 and IFN-gamma production in asthma have been found to be decreased, and this may reduce their capacity to inhibit IgE synthesis and allergic inflammation. IL-10 is a potent inhibitor of monocyte/macrophage function, suppressing the production of many pro-inflammatory cytokines. A relative underproduction of IL-10 from alveolar macrophages of atopic asthmatics has been reported. Therapeutic modulation of T(H1)/T(H2) imbalance in asthma and allergy by mycobacterial vaccine, specific immunotherapy and cytoline-guanosine dinucleotide motif may lead to increases in IL-12 and IFN-gamma production. Stimulation of IL-10 production by antigen-specific T-cells during immunotherapy may lead to anergy through inhibition of CD28-costimulatory molecule signalling by IL-10s anti-inflammatory effect on basophils, mast cells and eosinophils

    Study of pesudoscalar transition form factors within light front quark model

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    We study the transition form factors of the pesudoscalar mesons (Ο€,Ξ·\pi,\eta and Ξ·β€²\eta^{\prime}) as functions of the momentum transfer Q2Q^2 within the light-front quark model. We compare our results with the recent experimental data by CELLO, CLEO, BaBar and Belle. By considering the possible uncertainties from the quark masses, we illustrate that our predicted form factors can fit with all the data, including those at the large Q2Q^2 regions.Comment: 10 pages, 4 figures, accepted for publication in Phys. Rev.

    Supersolid phases in the extended boson hubbard model

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    We present a comprehensive numerical study on the ground state phase diagram of the two-dimensional hardcore boson extended Hubbard model with nearest (V1V_1) and next nearest neighbor (V2V_2) repulsions. In addition to the quantum solid and superfluid phases, we report the existence of striped supersolid and three-quarter (quarter) filled supersolid at commensurate density ρ=0.75\rho=0.75 (0.25) due to the interplay of V1V_1 and V2V_2 interactions. The nature of three-quarter filled supersolid and the associated quantum solid will be discussed. Quantum phase transition between the two supersolids of different symmetries is observed and is clearly of first order.Comment: 4 pages, 6 figure

    Commensurate lock-in and incommensurate supersolid phases of hardcore bosons on anisotropic triangular lattices

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    We investigate the interplay between commensurate lock-in and incommensurate supersolid phases of the hardcore bosons at half-filling with anisotropic nearest-neighbor hopping and repulsive interactions on triangular lattice. We use numerical quantum and variational Monte Carlo as well as analytical Schwinger boson mean-field analysis to establish the ground states and phase diagram. It is shown that, for finite size systems, there exist a series of jumps between different supersolid phases as the anisotropy parameter is changed. The density ordering wavevectors are locked to commensurate values and jump between adjacent supersolids. In the thermodynamic limit, however, the magnitude of these jumps vanishes leading to a continuous set of novel incommensurate supersoild phases.Comment: 5 pages, 5 figures, added new results, changed title and conclusio
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