1,790 research outputs found

    Parallel Contests

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    A problem of Parallel Contests is raised and modeled. The equilibria in final situations of parallel contests are analyzed and characterized and the behaviours of contestants with different abilities’ parameters are explained. Given that the values of the prizes in the two contests are different, in equilibrium a group of strong players prefer entering into the contest with a higher prize. However, except the group of stronger ones, in equilibrium others will enter into both contests because they obtain equal expected revenue from the two contests, though these weak ones do not have equal probabilities to enter into the two parallel contests. Under the condition of rationalizability, this paper characterizes the respective distributions of contestants’ abilities in the two parallel contests, proves the existence of the equilibrium in parallel contests and completes the analysis of the parallel contests from the perspective of contestants.Parallel contests, Contest, Strategic behaviours

    Three Sequential Cases: from Symmetry to Asymmetry

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    Three critical cases, involving asymmetric and symmetric cases, in the sequential stages of the n-player repeated auctions are analyzed and compared. These cases might arise in a process of sequential, identical or equivalent auctions, where the auction result may reveal information about the strength or competitiveness of the participants. The behaviours of different players are characterized. Generally a player bids more aggressively when facing a strong player rather than a weak player. However a player favours competing with a weak one rather than a strong one. By applying the concept of Conditional Stochastic Dominance, revenues of players and the seller between the three stages are compared. It is proved that in this sequential process the information structure of the auctions changes and the seller’s revenue increases. Finally, this n-player asymmetric auction model can also be used to compare the revenues between high-bid and open auctions and especially the results first derived by Maskin and Riley (2000) in two-player case are proved to be valid in the n-player case.Asymmetric auction; Revenue comparison

    DJpsiFDC: an event generator for the process ggJ/ψJ/ψgg\to J/\psi J/\psi at LHC

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    DJpsiFDC is an event generator package for the process ggJ/ψJ/ψgg\to J/\psi J/\psi. It generates events for primary leading-order 222\to 2 processes. The package could generate a LHE document and this document could easily be embedded into detector simulation software frameworks. The package is produced in Fortran codes.Comment: 10 pages, 3 figure

    Nested Sampling and its Applications in Stable Compressive Covariance Estimation and Phase Retrieval with Near-Minimal Measurements

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    Compressed covariance sensing using quadratic samplers is gaining increasing interest in recent literature. Covariance matrix often plays the role of a sufficient statistic in many signal and information processing tasks. However, owing to the large dimension of the data, it may become necessary to obtain a compressed sketch of the high dimensional covariance matrix to reduce the associated storage and communication costs. Nested sampling has been proposed in the past as an efficient sub-Nyquist sampling strategy that enables perfect reconstruction of the autocorrelation sequence of Wide-Sense Stationary (WSS) signals, as though it was sampled at the Nyquist rate. The key idea behind nested sampling is to exploit properties of the difference set that naturally arises in quadratic measurement model associated with covariance compression. In this thesis, we will focus on developing novel versions of nested sampling for low rank Toeplitz covariance estimation, and phase retrieval, where the latter problem finds many applications in high resolution optical imaging, X-ray crystallography and molecular imaging. The problem of low rank compressive Toeplitz covariance estimation is first shown to be fundamentally related to that of line spectrum recovery. In absence if noise, this connection can be exploited to develop a particular kind of sampler called the Generalized Nested Sampler (GNS), that can achieve optimal compression rates. In presence of bounded noise, we develop a regularization-free algorithm that provably leads to stable recovery of the high dimensional Toeplitz matrix from its order-wise minimal sketch acquired using a GNS. Contrary to existing TV-norm and nuclear norm based reconstruction algorithms, our technique does not use any tuning parameters, which can be of great practical value. The idea of nested sampling idea also finds a surprising use in the problem of phase retrieval, which has been of great interest in recent times for its convex formulation via PhaseLift, By using another modified version of nested sampling, namely the Partial Nested Fourier Sampler (PNFS), we show that with probability one, it is possible to achieve a certain conjectured lower bound on the necessary measurement size. Moreover, for sparse data, an l1 minimization based algorithm is proposed that can lead to stable phase retrieval using order-wise minimal number of measurements

    Phonon and Raman scattering of two-dimensional transition metal dichalcogenides from monolayer, multilayer to bulk material

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    Two-dimensional (2D) transition metal dichalcogenide (TMD) nanosheets exhibit remarkable electronic and optical properties. The 2D features, sizable bandgaps, and recent advances in the synthesis, characterization, and device fabrication of the representative MoS2_2, WS2_2, WSe2_2, and MoSe2_2 TMDs make TMDs very attractive in nanoelectronics and optoelectronics. Similar to graphite and graphene, the atoms within each layer in 2D TMDs are joined together by covalent bonds, while van der Waals interactions keep the layers together. This makes the physical and chemical properties of 2D TMDs layer dependent. In this review, we discuss the basic lattice vibrations of monolayer, multilayer, and bulk TMDs, including high-frequency optical phonons, interlayer shear and layer breathing phonons, the Raman selection rule, layer-number evolution of phonons, multiple phonon replica, and phonons at the edge of the Brillouin zone. The extensive capabilities of Raman spectroscopy in investigating the properties of TMDs are discussed, such as interlayer coupling, spin--orbit splitting, and external perturbations. The interlayer vibrational modes are used in rapid and substrate-free characterization of the layer number of multilayer TMDs and in probing interface coupling in TMD heterostructures. The success of Raman spectroscopy in investigating TMD nanosheets paves the way for experiments on other 2D crystals and related van der Waals heterostructures.Comment: 30 pages, 23 figure

    The Reduced Order Method for Solving the Linear Complementarity Problem with an M-Matrix

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    In this paper, by seeking the zero and the positive entry positions of the solution, we provide a direct method, called the reduced order method, for solving the linear complementarity problem with an M-matrix. By this method, the linear complementarity problem is transformed into a low order linear complementarity problem with some low order linear equations and the solution is constructed by the solution of the low order linear complementarity problem and the solutions of these low order linear equations in the transformations. In order to show the accuracy and the effectiveness of the method, the corresponding numerical experiments are performed