5,645 research outputs found
Effective Fitness Landscapes for Evolutionary Systems
In evolution theory the concept of a fitness landscape has played an
important role, evolution itself being portrayed as a hill-climbing process on
a rugged landscape. In this article it is shown that in general, in the
presence of other genetic operators such as mutation and recombination,
hill-climbing is the exception rather than the rule. This descrepency can be
traced to the different ways that the concept of fitness appears --- as a
measure of the number of fit offspring, or as a measure of the probability to
reach reproductive age. Effective fitness models the former not the latter and
gives an intuitive way to understand population dynamics as flows on an
effective fitness landscape when genetic operators other than selection play an
important role. The efficacy of the concept is shown using several simple
analytic examples and also some more complicated cases illustrated by
simulations.Comment: 11 pages, 8 postscript figure
Use of genetic algorithms and gradient based optimization techniques for calcium phosphate precipitation
Phase equilibrium computations constitute an important problem for designing and optimizing crystallization processes. The Gibbs free
energy is generally used as an objective function to find phase amount and composition at equilibrium. In such problems, the Gibbs free
energy may be a quite complex function, with several local minima. This paper presents a contribution to handle this kind of problems by
implementation of an optimization technique based on the successive use of a genetic algorithm (GA) and of a classical sequential quadratic
programming (SQP) method: the GA is used to perform a preliminary search in the solution space for locating the neighborhood of the
solution. Then, the SQP method is employed to refine the best solution provided by the GA. The basic operations involved in the design of
the GA developed in this study (encoding with binary representation of real values, evaluation function, adaptive plan) are presented. Several
test problems are first presented to demonstrate the validity of the approach. Then, calcium phosphate precipitation which is of major interest
for P-recovery from wastewater, has been chosen as an illustration of the implemented algorithm
An evolutionary approach to the optimisation of autonomous pod distribution for application in an urban transportation service
For autonomous vehicles (AVs), which when deployed in urban areas are called āpodsā, to be used as part of a commercially viable low-cost urban transport system, they will need to operate efficiently. Among ways to achieve efficiency, is to minimise time vehicles are not serving users. To reduce the amount of wasted time, this paper presents a novel approach for distribution of AVs within an urban environment. Our approach uses evolutionary computation, in the form of a genetic algorithm (GA), which is applied to a simulation of an intelligent transportation service, operating in the city of Coventry, UK. The goal of the GA is to optimise distribution of pods, to reduce the amount of user waiting time. To test the algorithm, real-world transport data was obtained for Coventry, which in turn was processed to generate user demand patterns. Results from the study showed a 30% increase in the number of successful journeys completed in a 24 hours, compared to a random distribution. The implications of these findings could yield significant benefits for fleet management companies. These include increases in profits per day, a decrease in capital cost, and better energy efficiency. The algorithm could also be adapted to any service offering pick up and drop of points, including package delivery and transportation of goods
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