217,721 research outputs found
Evolutionary algorithms for dynamic optimization problems: workshop preface
Copyright @ 2005 AC
Flavor structure from misalignment of inner products in noncommutative geometry
In this letter, we consider an idea that induces flavor structure from inner
products in noncommutative geometry. Assuming proper components of vectors
in enlarged representation space for fermions, we can induce the
waterfall texture for Yukawa matrices retaining gauge interactions are
universal. The hierarchy of the Yukawa interactions is a consequence of
"misalignment" between the vectors and .Comment: 6pages, 1 table, the final version to appear in JHE
Asymmetric vortex solitons in nonlinear periodic lattices
We reveal the existence of asymmetric vortex solitons in ideally symmetric
periodic lattices, and show how such nonlinear localized structures describing
elementary circular flows can be analyzed systematically using the
energy-balance relations. We present the examples of rhomboid, rectangular, and
triangular vortex solitons on a square lattice, and also describe novel
coherent states where the populations of clockwise and anti-clockwise vortex
modes change periodically due to a nonlinearity-induced momentum exchange
through the lattice. Asymmetric vortex solitons are expected to exist in
different nonlinear lattice systems including optically-induced photonic
lattices, nonlinear photonic crystals, and Bose-Einstein condensates in optical
lattices.Comment: 4 pages, 5 figure
Genetic algorithms with elitism-based immigrants for changing optimization problems
Copyright @ Springer-Verlag Berlin Heidelberg 2007.Addressing dynamic optimization problems has been a challenging task for the genetic algorithm community. Over the years, several approaches have been developed into genetic algorithms to enhance their performance in dynamic environments. One major approach is to maintain the diversity of the population, e.g., via random immigrants. This paper proposes an elitism-based immigrants scheme for genetic algorithms in dynamic environments. In the scheme, the elite from previous generation is used as the base to create immigrants via mutation to replace the worst individuals in the current population. This way, the introduced immigrants are more adapted to the changing environment. This paper also proposes a hybrid scheme that combines the elitism-based immigrants scheme with traditional random immigrants scheme to deal with significant changes. The experimental results show that the proposed elitism-based and hybrid immigrants schemes efficiently improve the performance of genetic algorithms in dynamic environments
Effective range expansion in various scenarios of EFT(\notpi)
Using rigorous solutions, we compare the ERE parameters obtained in three
different scenarios of EFT(\notpi) in nonperturbative regime. A scenario with
unconventional power counting (like KSW) is shown to be disfavored by the PSA
data, while the one with elaborate prescription of renormalization but keeping
conventional power counting intact seems more promising.Comment: 6 pages, 3 tables, no figure, revtex4-1, minor revisions, to appear
in EP
Light-Driven Hydrogen Production from Aqueous Solutions Based on a New Dubois-Type Nickel Catalyst
In this work, we report a new photocatalytic system that links multifunctional semiconductor nanocrystals with emerging water-soluble molecular catalysts made of earth-abundant elements for H2 generation [Ni(P2RN2R′)2(BF4)2]4−, R = Ph, R′ = [PhSO3]− (NiS). This noble metal free hybrid exhibits remarkable catalytic activity with a turnover number of 511 for H2 production and a photon-to-H2 conversion efficiency of 12.5%. The mechanistic insight into such high efficiency in this photocatalytic system was examined using a combination of steady-state emission and time-resolved absorption spectroscopy
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