21,992 research outputs found

    Policy compass: FCM-based policy impact evaluation using public open data

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    This paper presents how Fuzzy Cognitive Map (FCM) technique can be applied by a policy maker to support the policy impact evaluation using the example of Policy Compass, an EU research project. The practical usage example on interest rate policy shows the potential of FCMs as a policy impact modelling tool. Through the provision of a more intuitive and easier means of using open data based on FCM techniques, the Policy Compass project can play a critical role for both policy maker and lay public to evaluate the policy impact and prepare for future policy making

    Speculations on Isolated Lepton Events at HERA

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    Speculations on mechanisms which might be responsible for events with an isolated high p_T lepton, a hadron jet and missing energy, as observed in the H1 experiment at HERA, are discussed.Comment: LaTeX, 6 pages, 2 figures, presented at the XXXI Conference of Theoretical Physics "Matter to the Deepest", Ustron, Poland, September 5-11, 200

    TeV scale mirage mediation in NMSSM

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    We study the next-to-minimal supersymmetric standard model. We consider soft supersymmetry breaking parameters, which are induced by the mirage mediation mechanism of supersymmetry breaking. We concentrate on the mirage mediation, where the so-called mirage scale is the TeV scale. In this scenario, we can realize the up-type Higgs soft mass of O(200) GeV, while other masses such as gaugino masses and stop masses are heavy such as 1 TeV or more. Cancellation between the effective \mu-term and the down-type Higgs soft mass ameliorates the fine-tuning in the electroweak symmetry breaking even for \mu=O(500) GeV. The mixing between the doublet and singlet Higgs bosons is suppressed by (\lambda/\kappa)/tan\beta. Then the lightest doublet Higgs mass naturally reaches 125 GeV lifted by the new quartic coupling. The higgsino and singlino are light and their linear combination is the lightest superparticle.Comment: 24 pages, 24 figures, Numerical analysis is replaced with the version calculated by NMSSMTools. Comments and references are added on the suppressed doublet-singlet mixing and cases in which the 125 GeV boson is the 2nd lightest CP-even scalar. The version accepted by JHE

    A Characterization of Visibility Graphs for Pseudo-Polygons

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    In this paper, we give a characterization of the visibility graphs of pseudo-polygons. We first identify some key combinatorial properties of pseudo-polygons, and we then give a set of five necessary conditions based off our identified properties. We then prove that these necessary conditions are also sufficient via a reduction to a characterization of vertex-edge visibility graphs given by O'Rourke and Streinu

    Inflation with blowing-up solution of cosmological constant problem

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    The cosmological constant problem is how one chooses, without fine-tuning, one singular point Λeff=0\Lambda_{eff}=0 for the 4D cosmological constant. We argue that some recently discovered {\it weak self-tuning} solutions can be viewed as blowing-up this one point into a band of some parameter. These weak self-tuning solutions may have a virtue that only de Sitter space solutions are allowed outside this band, allowing an inflationary period. We adopt the hybrid inflation at the brane to exit from this inflationary phase and to enter into the standard Big Bang cosmology.Comment: LaTeX file of 20 pages including 2 eps figure

    Magnetic Excitations and Continuum of a Field-Induced Quantum Spin Liquid in α\alpha-RuCl3_3

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    We report on terahertz spectroscopy of quantum spin dynamics in α\alpha-RuCl3_3, a system proximate to the Kitaev honeycomb model, as a function of temperature and magnetic field. An extended magnetic continuum develops below the structural phase transition at Ts2=62T_{s2}=62K. With the onset of a long-range magnetic order at TN=6.5T_N=6.5K, spectral weight is transferred to a well-defined magnetic excitation at ℏω1=2.48\hbar \omega_1 = 2.48meV, which is accompanied by a higher-energy band at ℏω2=6.48\hbar \omega_2 = 6.48meV. Both excitations soften in magnetic field, signaling a quantum phase transition at Bc=7B_c=7T where we find a broad continuum dominating the dynamical response. Above BcB_c, the long-range order is suppressed, and on top of the continuum, various emergent magnetic excitations evolve. These excitations follow clear selection rules and exhibit distinct field dependencies, characterizing the dynamical properties of the field-induced quantum spin liquid

    Reconstruction of Fundamental SUSY Parameters

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    We summarize methods and expected accuracies in determining the basic low-energy SUSY parameters from experiments at future e+^+e−^- linear colliders in the TeV energy range, combined with results from LHC. In a second step we demonstrate how, based on this set of parameters, the fundamental supersymmetric theory can be reconstructed at high scales near the grand unification or Planck scale. These analyses have been carried out for minimal supergravity [confronted with GMSB for comparison], and for a string effective theory.Comment: 8 pages, latex, 7 figures, expanded version of contributions to the proceedings of ICHEP.2002 (Amstersdam) and LCWS.2002 (Jeju Island

    Interoperability framework for supporting information-based assistance in the factory

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    The aim of this paper is to propose new interoperability solution, based on Info-Engine framework and web services technology to support data exchange and extraction from PLM system, specially the Windchill tool. This solution will be implemented as a connector module of more generic framework, named Digital Factory Assistant (DFA). The DFA framework aims to provide factory workers by a set of knowledge and information based decision support to improve their activity performance

    Size effect on magnetism of Fe thin films in Fe/Ir superlattices

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    In ferromagnetic thin films, the Curie temperature variation with the thickness is always considered as continuous when the thickness is varied from nn to n+1n+1 atomic planes. We show that it is not the case for Fe in Fe/Ir superlattices. For an integer number of atomic planes, a unique magnetic transition is observed by susceptibility measurements, whereas two magnetic transitions are observed for fractional numbers of planes. This behavior is attributed to successive transitions of areas with nn and n+1n+1 atomic planes, for which the TcT_c's are not the same. Indeed, the magnetic correlation length is presumably shorter than the average size of the terraces. Monte carlo simulations are performed to support this explanation.Comment: LaTeX file with Revtex, 5 pages, 5 eps figures, to appear in Phys. Rev. Let
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