95,587 research outputs found
Differential evolution with an evolution path: a DEEP evolutionary algorithm
Utilizing cumulative correlation information already existing in an evolutionary process, this paper proposes a predictive approach to the reproduction mechanism of new individuals for differential evolution (DE) algorithms. DE uses a distributed model (DM) to generate new individuals, which is relatively explorative, whilst evolution strategy (ES) uses a centralized model (CM) to generate offspring, which through adaptation retains a convergence momentum. This paper adopts a key feature in the CM of a covariance matrix adaptation ES, the cumulatively learned evolution path (EP), to formulate a new evolutionary algorithm (EA) framework, termed DEEP, standing for DE with an EP. Without mechanistically combining two CM and DM based algorithms together, the DEEP framework offers advantages of both a DM and a CM and hence substantially enhances performance. Under this architecture, a self-adaptation mechanism can be built inherently in a DEEP algorithm, easing the task of predetermining algorithm control parameters. Two DEEP variants are developed and illustrated in the paper. Experiments on the CEC'13 test suites and two practical problems demonstrate that the DEEP algorithms offer promising results, compared with the original DEs and other relevant state-of-the-art EAs
Neutrino Propagation In Color Superconducting Quark Matter
We calculate the neutrino mean free path in color superconducting quark
matter, and employ it to study the cooling of matter via neutrino diffusion in
the superconducting phase as compared to a free quark phase. The cooling
process slows when quark matter undergoes a second order phase transition to a
superconducting phase at the critical temperature . Cooling subsequently
accelerates as the temperature decreases below . This will directly impact
the early evolution of a newly born neutron star should its core contain quark
matter. Consequently, there may be observable changes in the early neutrino
emission which would provide evidence for superconductivity in hot and dense
matter.Comment: 12 pages, 5 figure
Optimisation of Mobile Communication Networks - OMCO NET
The mini conference “Optimisation of Mobile Communication Networks” focuses on advanced methods for search and optimisation applied to wireless communication networks. It is sponsored by Research & Enterprise Fund Southampton Solent University.
The conference strives to widen knowledge on advanced search methods capable of optimisation of wireless communications networks. The aim is to provide a forum for exchange of recent knowledge, new ideas and trends in this progressive and challenging area. The conference will popularise new successful approaches on resolving hard tasks such as minimisation of transmit power, cooperative and optimal routing
An Improved Differential Evolution Algorithm for Maritime Collision Avoidance Route Planning
High accuracy navigation and surveillance systems are pivotal to ensure efficient ship route planning and marine safety. Based on existing ship navigation and maritime collision prevention rules, an improved approach for collision avoidance route planning using a differential evolution algorithm was developed. Simulation results show that the algorithm is capable of significantly enhancing the optimized route over current methods. It has the potential to be used as a tool to generate optimal vessel routing in the presence of conflicts
Fast micro-differential evolution for topological active net optimization
This paper studies the optimization problem of topological active net (TAN), which is often seen in image segmentation and shape modeling. A TAN is a topological structure containing many nodes, whose positions must be optimized while a predefined topology needs to be maintained. TAN optimization is often time-consuming and even constructing a single solution is hard to do. Such a problem is usually approached by a ``best improvement local search'' (BILS) algorithm based on deterministic search (DS), which is inefficient because it spends too much efforts in nonpromising probing. In this paper, we propose the use of micro-differential evolution (DE) to replace DS in BILS for improved directional guidance. The resultant algorithm is termed deBILS. Its micro-population efficiently utilizes historical information for potentially promising search directions and hence improves efficiency in probing. Results show that deBILS can probe promising neighborhoods for each node of a TAN. Experimental tests verify that deBILS offers substantially higher search speed and solution quality not only than ordinary BILS, but also the genetic algorithm and scatter search algorithm
Neutrino scattering rates in the presence of hyperons from a Skyrme model in the RPA approximation
The contribution of Lambda hyperons to neutrino scattering rates is
calculated in the random phase approximation in a model where the interaction
is described by a Skyrme potential. Finite temperature and neutrino trapping
are taken into account in view of applications to the deleptonization stage of
protoneutron star cooling. The hyperons can remove the problem of ferromagnetic
instability common to (nearly) all Skyrme parametrizations of the
nucleon-nucleon interaction. As a consequence, there is not any longer a pole
at the transition in the neutrino-baryon cross section. However there still
remains an enhancement in this region. In the absence of ferromagnetism the
mean free path in npLambda matter is reduced compared to its value in np matter
as consequence of the presence of this additional degree of freedom. At high
density the results are very sensitive to the choice of the Lambda-Lambda
interaction.Comment: 21 pages, 13 figure
Applications of the wave packet method to resonant transmission and reflection gratings
Scattering of femtosecond laser pulses on resonant transmission and
reflection gratings made of dispersive (Drude metals) and dielectric materials
is studied by a time-domain numerical algorithm for Maxwell's theory of linear
passive (dispersive and absorbing) media. The algorithm is based on the
Hamiltonian formalism in the framework of which Maxwell's equations for passive
media are shown to be equivalent to the first-order equation, , where is a linear differential
operator (Hamiltonian) acting on a multi-dimensional vector built of the
electromagnetic inductions and auxiliary matter fields describing the medium
response. The initial value problem is then solved by means of a modified time
leapfrog method in combination with the Fourier pseudospectral method applied
on a non-uniform grid that is constructed by a change of variables and designed
to enhance the sampling efficiency near medium interfaces. The algorithm is
shown to be highly accurate at relatively low computational costs. An excellent
agreement with previous theoretical and experimental studies of the gratings is
demonstrated by numerical simulations using our algorithm. In addition, our
algorithm allows one to see real time dynamics of long leaving resonant
excitations of electromagnetic fields in the gratings in the entire frequency
range of the initial wide band wave packet as well as formation of the
reflected and transmitted wave fronts.Comment: 23 pages; 8 figures in the png forma
Next-to-Next-to-Leading Electroweak Logarithms in W-pair Production at ILC
We derive the high energy asymptotic behavior of gauge boson production cross
section in a spontaneously broken SU(2) gauge theory in the
next-to-next-to-leading logarithmic approximation. On the basis of this result
we obtain the logarithmically enhanced two-loop electroweak corrections to the
differential cross section of W-pair production at ILC/CLIC up to the second
power of the large logarithm.Comment: 17 pages, LaTeX, Eqs. (31) and (35) correcte
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