10,807 research outputs found
(Almost) Everything You Always Wanted to Know About Deterministic Control Problems in Stratified Domains
We revisit the pioneering work of Bressan \& Hong on deterministic control
problems in stratified domains, i.e. control problems for which the dynamic and
the cost may have discontinuities on submanifolds of R N . By using slightly
different methods, involving more partial differential equations arguments, we
(i) slightly improve the assumptions on the dynamic and the cost; (ii) obtain a
comparison result for general semi-continuous sub and supersolutions (without
any continuity assumptions on the value function nor on the
sub/supersolutions); (iii) provide a general framework in which a stability
result holds
ESTIMATION OF INCOME DISTRIBUTION AND DETECTION OF SUBPOPULATIONS: AN EXPLANATORY MODEL
Inequality and polarization analyses are complementary but conceptually different. They are usually implemented independently in practic e, with different a priori assumptions and different tools. In this paper, we develop a unique method to study simultaneously these different and complementary concerns. Based on mixture models, the method we develop includes at the same time : an estimation of income distribution with no a priori assumptions - a decomposition in several homogeneous subpopulations - an explanatory model to study the structure of the income distribution.
Power Estimation in LTE systems with the General Framework of Standard Interference Mappings
We devise novel techniques to obtain the downlink power inducing a given load
in long-term evolution (LTE) systems, where we define load as the fraction of
resource blocks in the time-frequency grid being requested by users from a
given base station. These techniques are particularly important because
previous studies have proved that the data rate requirement of users can be
satisfied with lower transmit energy if we allow the load to increase. Those
studies have also shown that obtaining the power assignment from a desired load
profile can be posed as a fixed point problem involving standard interference
mappings, but so far the mappings have not been obtained explicitly. One of our
main contributions in this study is to close this gap. We derive an
interference mapping having as its fixed point the power assignment inducing a
desired load, assuming that such an assignment exists. Having this mapping in
closed form, we simplify the proof of the aforementioned known results, and we
also devise novel iterative algorithms for power computation that have many
numerical advantages over previous methods.Comment: IEEE Global SIP 201
Probing double parton scattering via associated open charm and bottom production in ultraperipheral collisions
In this article, we propose a novel channel for phenomenological studies of
the double-parton scattering (DPS) based upon associated production of charm
and bottom quark pairs in well-separated rapidity
intervals in ultra-peripheral high-energy proton-nucleus collisions. This
process provides a direct access to the double-gluon distribution in the proton
at small- and enables one to test the factorised DPS pocket formula. We have
made the corresponding theoretical predictions for the DPS contribution to this
process at typical LHC energies and beyond and we compute the
energy-independent (but photon momentum fraction dependent) effective cross
section.Comment: 15 pages, 7 figs., 1 table. One fig. added. Version accepted for
publication at EPJ
Prediction of pressure drop in multiphase horizontal pipe flow
Empirical correlations were tested against reliable two phase pipe flow data for the prediction of pressure drop. Correlations are recommended for the prediction with stratified and annular type flows. When these correlations were adapted to three phase gaswater-oil pipe flow in general they predicted for intermittent slug type flows. Momentum balance models could not be successfully adapted to the prediction of pipe three phase pressure drop
Texture Zeros and Weak Basis Transformations
We investigate the physical meaning of some of the "texture zeros" which
appear in most of the Ansatze on quark masses and mixings. It is shown that
starting from arbitrary quark mass matrices and making a suitable weak basis
transformation one can obtain some of these sets of zeros which therefore have
no physical content. We then analyse the physical implications of a
four-texture zero Ansatz which is in agreement with all present experimental
data.Comment: 11 pages, typeset using revte
Exclusive heavy quark-pair production in ultraperipheral collisions
In this article, we study the fully differential observables of exclusive
production of heavy (charm and bottom) quark pairs in high-energy
ultraperipheral and collisions. In these processes, the nucleus
serves as an efficient source of the photon flux, while the QCD interaction of
the produced heavy-quark pair with the target ( or ) proceeds via an
exchange of gluons in a color singlet state, described by the gluon Wigner
distribution. The corresponding predictions for differential cross sections
were obtained by using the dipole -matrix in the McLerran--Venugopalan
saturation model with impact parameter dependence for the nucleus target, and
its recent generalization, for the proton target. Prospects of experimental
constraints on the gluon Wigner distribution in this class of reactions are
discussed.Comment: 21 pages, 18 figures, improved conclusio
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