1,186,799 research outputs found
Astrocladistics: Multivariate Evolutionary Analysis in Astrophysics
The Hubble tuning fork diagram, based on morphology and established in the
1930s, has always been the preferred scheme for classification of galaxies.
However, the current large amount of data up to higher and higher redshifts
asks for more sophisticated statistical approaches like multivariate analyses.
Clustering analyses are still very confidential, and do not take into account
the unavoidable characteristics in our Universe: evolution. Assuming branching
evolution of galaxies as a 'transmission with modification', we have shown that
the concepts and tools of phylogenetic systematics (cladistics) can be
heuristically transposed to the case of galaxies. This approach that we call
"astrocladistics", has now successfully been applied on several samples of
galaxies and globular clusters. Maximum parsimony and distance-based approaches
are the most popular methods to produce phylogenetic trees and, like most other
studies, we had to discretize our variables. However, since astrophysical data
are intrinsically continuous, we are contributing to the growing need for
applying phylogenetic methods to continuous characters.Comment: Invited talk at the session: Astrostatistics (Statistical analysis of
data related to Astronomy and Astrophysics
Evolutionary stability in quantum games
In evolutionary game theory an Evolutionarily Stable Strategy (ESS) is a
refinement of the Nash equilibrium concept that is sometimes also recognized as
evolutionary stability. It is a game-theoretic model, well known to
mathematical biologists, that was found quite useful in the understanding of
evolutionary dynamics of a population. This chapter presents an analysis of
evolutionary stability in the emerging field of quantum games.Comment: 38 pages, 2 figures, contributed chapter to the book "Quantum Aspects
of Life" edited by D. Abbott, P. Davies and A. Pat
Natural selection. III. Selection versus transmission and the levels of selection
George Williams defined an evolutionary unit as hereditary information for
which the selection bias between competing units dominates the informational
decay caused by imperfect transmission. In this article, I extend Williams'
approach to show that the ratio of selection bias to transmission bias provides
a unifying framework for diverse biological problems. Specific examples include
Haldane and Lande's mutation-selection balance, Eigen's error threshold and
quasispecies, Van Valen's clade selection, Price's multilevel formulation of
group selection, Szathmary and Demeter's evolutionary origin of primitive
cells, Levin and Bull's short-sighted evolution of HIV virulence, Frank's
timescale analysis of microbial metabolism, and Maynard Smith and Szathmary's
major transitions in evolution. The insights from these diverse applications
lead to a deeper understanding of kin selection, group selection, multilevel
evolutionary analysis, and the philosophical problems of evolutionary units and
individuality
Pseudo derivative evolutionary algorithm and convergence analysis
In this paper, a novel evolutionary algorithm (EA), called pseudo-derivative EA (called PDEA), is proposed. The basic idea of PDEA is to use pseudo-derivative, which is obtained based on the information produced during the evolution, and to help search the solution of optimization problem. The pseudo-derivative drives the search process in a more informed direction. That makes PDEA different from the random optimization methods. The convergence of PDEA is first analyzed based on systems theory. The convergence condition of PDEA is then derived though this condition is too strong to be satisfied. Next, this condition is relaxed based on the entropy theory. Finally, performances of PDEA are evaluated on the benchmark functions and an adaptive liquid level control system of a surge tank. The numeric simulation results show that PDEA is capable of finding the solutions to the optimization problems with good accuracy, reliability, and speed.</jats:p
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