11,578 research outputs found
Electromechanical behavior of BaTiO3 from first principles
Using an effective Hamiltonian parametrized from first principles, Monte
Carlo simulations are performed in order to study the piezoelectric response of
BaTiO3 in the ferroelectric tetragonal phase as a function of temperature. The
effect of an electric field on the phase behavior is also illustrated by a
simulation of the transformation of a rhombohedral domain into a tetragonal one
under a strong field.Comment: 3 pages, two-column style with 3 postscript figures embedded. Uses
REVTEX and epsf macros. Also available at
http://www.physics.rutgers.edu/~dhv/preprints/index.html#ag_pie
Scheduling commercial advertisements for television
The problem of scheduling the commercial advertisements in the television industry is investigated. Each advertiser client demands that the multiple airings of the same brand advertisement should be as spaced as possible over a given time period. Moreover, audience rating requests have to be taken into account in the scheduling. This is the first time this hard decision problem is dealt with in the literature. We design two mixed integer linear programming (MILP) models. Two constructive heuristics, local search procedures and simulated annealing (SA) approaches are also proposed. Extensive computational experiments, using several instances of various sizes, are performed. The results show that the proposed MILP model which represents the problem as a network flow obtains a larger number of optimal solutions and the best non-exact procedure is the one that uses SA
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