46,203 research outputs found

    An information theory for preferences

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    Recent literature in the last Maximum Entropy workshop introduced an analogy between cumulative probability distributions and normalized utility functions. Based on this analogy, a utility density function can de defined as the derivative of a normalized utility function. A utility density function is non-negative and integrates to unity. These two properties form the basis of a correspondence between utility and probability. A natural application of this analogy is a maximum entropy principle to assign maximum entropy utility values. Maximum entropy utility interprets many of the common utility functions based on the preference information needed for their assignment, and helps assign utility values based on partial preference information. This paper reviews maximum entropy utility and introduces further results that stem from the duality between probability and utility

    Extended Minimal Flavour Violating MSSM and Implications for B Physics

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    The recently reported measurements of the CP asymmetry a(psi K) by the BABAR and BELLE collaborations are in good agreement with the standard model (SM) prediction, resulting from the unitarity of the CKM matrix. The so-called minimal flavour violating (MFV) supersymmetric extensions of the standard model, in which the CKM matrix remains the only flavour changing structure, predict a(psi K) similar to the one in the SM. With the anticipated precision in a(psi K) and other CP asymmetries at the B factories and hadron colliders, one hopes to pin down any possible deviation from the SM. We discuss an extension of the MFV-supersymmetric models which comfortably accommodates the current measurements of the CP asymmetry a(psi K), but differs from the SM and the MFV-supersymmetric models due to an additional flavour changing structure beyond the CKM matrix. We suggest specific tests in forthcoming experiments in B physics. In addition to the CP-asymmetries in B-meson decays, such as a(psi K) and a(pi pi), and the mass difference Delta M_s in the Bs-bar(Bs) system, we emphasize measurements of the radiative transition b -> d gamma as sensitive probes of the postulated flavour changing structure. Interestingly, the CKM-unitarity analysis in the Extended-MFV model also allows solutions rho < 0, as opposed to the SM and the MFV models for which only rho > 0 solutions are now admissible, implying gamma > pi/2, where gamma=- arg (Vub). Such large values of gamma are hinted by the current measurements of the branching ratios for the decays B -> pi pi and B -> K pi.Comment: 35 pages, 12 figures. Theoretical analysis modified in view of the recent CP violation observed in B-> J/Psi K decays. Resulting constraints on the model parameters are recompute

    Thermal response of large area high temperature superconducting YBaCuO infrared bolometer

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    Thermal analysis of large area high temperature superconducting infrared detector operating in the equilibrium mode (bolometer) was performed. An expression for the temperature coefficient beta=1/R(dR/dT) in terms of the thermal conductance and the thermal time constant of the detector were derived. A superconducting transition edge bolometer is a thermistor consisting of a thin film superconducting YBaCuO evaporated into a suitable thermally isolated substrate. The operating temperature of the bolometer is maintained close to the midpoint of the superconducting transition region where the resistance R has a maximum dynamic range. A detector with a strip configuration was analyzed and an expression for the temperature rise (delta T) above the ambient due to a uniform illumination with a source of power density P(sub i) was calculated. An expression for the thermal responsivity of the detector was derived using the thermal diffusion analysis with appropriate boundary conditions. It was found that the thermal responsibility depends upon the spatial modulation frequency and the angular frequency of the incoming radiation. The problem of the thermal cross talk between different detector elements was addressed. In the case of monolithic HTS detector array with a row of square elements of dimensions 2a and CCD or CID readout electronics the thermal spread function was derived for different spacing between elements. This analysis can be critical for future design and applications of large area focal plane arrays as broad band optical detectors made of granular thin films HTS YBaCuO

    Design and Simulation of Wave Shaping Schemes for a Virtual Data Communication and Impaired Link Environment System for Advanced ICT Education

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    Design and Simulation of Waves Shaping Schemes for a Virtual Data Communication and Impaired Link Environment System for Advanced ICT Education is aimed at providing a simulator for the performance of digital filtering of signals for data communication experiments with the aid of MATLAB. A fundamental aspect of signal processing is filtering. Filtering involves the manipulation of the spectrum of a signal by passing or blocking certain portions of the spectrum, depending on the frequency of those portions. This work is designed to provide a flexible platform for teaching the operations of waves shaping schemes (lowpass, bandpass and highpass) modelled over an additive white Gaussian noise (AWGN) channel. Keywords – Lowpass, Bandpass, Highpass, MATLAB
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