388 research outputs found
Adaptive intelligence applied to numerical optimisation
The article presents modification strategies theoretical comparison and experimental results achieved by adaptive heuristics applied to numerical optimisation of several non-constraint test functions. The aims of the study are to identify and compare how adaptive search heuristics behave within heterogeneous search space without retuning of the search parameters. The achieved results are summarised and analysed, which could be used for comparison to other methods and further investigation
The K\"ahler-Ricci flow with positive bisectional curvature
We show that the K\"ahler-Ricci flow on a manifold with positive first Chern
class converges to a K\"ahler-Einstein metric assuming positive bisectional
curvature and certain stability conditions.Comment: 15 page
Quantum Scattering from Classical Field Theory
We show that scattering amplitudes between initial wave packet states and
certain coherent final states can be computed in a systematic weak coupling
expansion about classical solutions satisfying initial value conditions. The
initial value conditions are such as to make the solution of the classical
field equations amenable to numerical methods. We propose a practical procedure
for computing classical solutions which contribute to high energy two particle
scattering amplitudes. We consider in this regard the implications of a recent
numerical simulation in classical SU(2) Yang-Mills theory for multiparticle
scattering in quantum gauge theories and speculate on its generalization to
electroweak theory. The generalization of our results to complex trajectories
allows its application to it any wave packet to coherent state transition.
Finally, we discuss the relevance of these results to the issues of baryon
number violation and multiparticle scattering at high energies.Comment: 20 pages, JHU-TIPAC-940003, HUTP-A0/007, Latex, uses prepictex.tex,
pictex.tex, and postpictex.tex (available by ftp from [email protected]) to
produce figure
A higher order control volume based finite element method to prodict the deformation of heterogeneous materials
Materials with obvious internal structure can exhibit behaviour, under loading, that cannot be described by classical elasticity. It is therefore important to develop computational tools incorporating appropriate constitutive theories that can capture their unconventional behaviour. One such theory is micropolar elasticity. This paper presents a linear strain control volume finite element formulation incorporating micropolar elasticity. Verification results from a micropolar element patch test as well as convergence results for a stress concentration problem are included. The element will be shown to pass the patch test and also exhibit accuracy that is at least equivalent to its finite element counterpart
Interaction Energies of Generalised Monopoles
Generalisations of the 't Hooft-Polyakov monopole which can exhibit repulsion
only, attraction only, and both attraction and repulsion, between like
monopoles, are studied numerically. The models supporting these solitons are
SO(3) gauged Higgs models featuring Skyrme-like terms.Comment: 46 pages, including 22 postscript figures, LaTex forma
Long range forces and limits on unparticle interactions
Couplings between standard model particles and unparticles from a nontrivial
scale invariant sector can lead to long range forces. If the forces couple to
quantities such as baryon or lepton (electron) number, stringent limits result
from tests of the gravitational inverse square law. These limits are much
stronger than from collider phenomenology and astrophysics.Comment: 7 pages, revtex; v2 minor changes and added reference
A Dynamic Island-Based Genetic Algorithms Framework
This work presents a dynamic island model framework for helping the resolution of combinatorial optimization problems with evolutionary algorithms. In this framework, the possible migrations among islands are represented by a complete graph. The migrations probabilities associated to each edge are dynamically updated with respect to the last migrations impact. This new framework is tested on the well-known 0/1 Knapsack problem and MAX-SAT problem. Good results are obtained and several properties of this framework are studied
Polyurethane Elastomers as Maxillofacial Prosthetic Materials
A series of polyurethane elastomers based on an aliphatic diisocyanate and a polyether macroglycol was polymerized with various crosslink densities and OH/NCO ratios. Stoichiometries yielding between 8,600 and 12,900 gm/ mole/crosslink and an OH/NCO ratio of 1.1 resulted in polymers with the low modulus, yet high strength and elongation necessary for maxillofacial applications.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/68299/2/10.1177_00220345780570040501.pd
Production and Decay of D_1(2420)^0 and D_2^*(2460)^0
We have investigated and final states and
observed the two established charmed mesons, the with mass
MeV/c and width MeV/c and
the with mass MeV/c and width
MeV/c. Properties of these final states, including
their decay angular distributions and spin-parity assignments, have been
studied. We identify these two mesons as the doublet predicted
by HQET. We also obtain constraints on {\footnotesize } as a function of the cosine of the relative phase of the two
amplitudes in the decay.Comment: 15 pages in REVTEX format. hardcopies with figures can be obtained by
sending mail to: [email protected]
Measurement of the branching fraction for
We have studied the leptonic decay of the resonance into tau
pairs using the CLEO II detector. A clean sample of tau pair events is
identified via events containing two charged particles where exactly one of the
particles is an identified electron. We find . The result is consistent with
expectations from lepton universality.Comment: 9 pages, RevTeX, two Postscript figures available upon request, CLNS
94/1297, CLEO 94-20 (submitted to Physics Letters B
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