1,304 research outputs found
Distributed evolutionary algorithms and their models: A survey of the state-of-the-art
The increasing complexity of real-world optimization problems raises new challenges to evolutionary computation. Responding to these challenges, distributed evolutionary computation has received considerable attention over the past decade. This article provides a comprehensive survey of the state-of-the-art distributed evolutionary algorithms and models, which have been classified into two groups according to their task division mechanism. Population-distributed models are presented with master-slave, island, cellular, hierarchical, and pool architectures, which parallelize an evolution task at population, individual, or operation levels. Dimension-distributed models include coevolution and multi-agent models, which focus on dimension reduction. Insights into the models, such as synchronization, homogeneity, communication, topology, speedup, advantages and disadvantages are also presented and discussed. The study of these models helps guide future development of different and/or improved algorithms. Also highlighted are recent hotspots in this area, including the cloud and MapReduce-based implementations, GPU and CUDA-based implementations, distributed evolutionary multiobjective optimization, and real-world applications. Further, a number of future research directions have been discussed, with a conclusion that the development of distributed evolutionary computation will continue to flourish
Evolutionary games on graphs
Game theory is one of the key paradigms behind many scientific disciplines
from biology to behavioral sciences to economics. In its evolutionary form and
especially when the interacting agents are linked in a specific social network
the underlying solution concepts and methods are very similar to those applied
in non-equilibrium statistical physics. This review gives a tutorial-type
overview of the field for physicists. The first three sections introduce the
necessary background in classical and evolutionary game theory from the basic
definitions to the most important results. The fourth section surveys the
topological complications implied by non-mean-field-type social network
structures in general. The last three sections discuss in detail the dynamic
behavior of three prominent classes of models: the Prisoner's Dilemma, the
Rock-Scissors-Paper game, and Competing Associations. The major theme of the
review is in what sense and how the graph structure of interactions can modify
and enrich the picture of long term behavioral patterns emerging in
evolutionary games.Comment: Review, final version, 133 pages, 65 figure
A symbiosis between cellular automata and genetic algorithms
Cellular automata are systems which use a rule to describe the evolution of a population in a discrete lattice, while genetic algorithms are procedures designed to find solutions to optimization problems inspired by the process of natural selection. In this paper, we introduce an original implementation of a cellular automaton whose rules use a fitness function to select for each cell the best mate to reproduce and a crossover operator to determine the resulting offspring. This new system, with a proper definition, can be both a cellular automaton and a genetic algorithm. We show that in our system the Conway’s Game of Life can be easily implemented and, consequently, it is capable of universal computing. Moreover two generalizations of the Game of Life are created and also implemented with it. Finally, we use our system for studying and implementing the prisoner’s dilemma and rock-paper-scissors games, showing very interesting behaviors and configurations (e.g., gliders) inside these games
Centric selection: a way to tune the exploration/exploitation trade-off
In this paper, we study the exploration / exploitation trade-off in cellular
genetic algorithms. We define a new selection scheme, the centric selection,
which is tunable and allows controlling the selective pressure with a single
parameter. The equilibrium model is used to study the influence of the centric
selection on the selective pressure and a new model which takes into account
problem dependent statistics and selective pressure in order to deal with the
exploration / exploitation trade-off is proposed: the punctuated equilibria
model. Performances on the quadratic assignment problem and NK-Landscapes put
in evidence an optimal exploration / exploitation trade-off on both of the
classes of problems. The punctuated equilibria model is used to explain these
results
Fault tolerant and dynamic evolutionary optimization engines
Mimicking natural evolution to solve hard optimization problems has played an important
role in the artificial intelligence arena. Such techniques are broadly classified
as Evolutionary Algorithms (EAs) and have been investigated for around four decades
during which important contributions and advances have been made.
One main evolutionary technique which has been widely investigated is the Genetic
Algorithm (GA). GAs are stochastic search techniques that follow the Darwinian
principle of evolution. Their application in the solution of hard optimization problems
has been very successful. Indeed multi-dimensional problems presenting difficult search
spaces with characteristics such as multi-modality, epistasis, non regularity, deceptiveness,
etc., have all been effectively tackled by GAs.
In this research, a competitive form of GAs known as fine or cellular GAs (cGAs)
are investigated, because of their suitability for System on Chip (SoC) implementation
when tackling real-time problems. Cellular GAs have also attracted the attention
of researchers due to their high performance, ease of implementation and massive
parallelism. In addition, cGAs inherently possess a number of structural configuration
parameters which make them capable of sustaining diversity during evolution and
therefore of promoting an adequate balance between exploitative and explorative stages
of the search.
The fast technological development of Integrated Circuits (ICs) has allowed a considerable
increase in compactness and therefore in density. As a result, it is nowadays
possible to have millions of gates and transistor based circuits in very small silicon
areas. Operational complexity has also significantly increased and consequently other
setbacks have emerged, such as the presence of faults that commonly appear in the
form of single or multiple bit flips. Tough environmental or time dependent operating
conditions can trigger faults in registers and memory allocations due to induced radiation, electron migration and dielectric breakdown. These kinds of faults are known as
Single Event Effects (SEEs).
Research has shown that an effective way of dealing with SEEs consists of a combination
of hardware and software mitigation techniques to overcome faulty scenarios.
Permanent faults known as Single Hard Errors (SHEs) and temporary faults known
as Single Event Upsets (SEUs) are common SEEs. This thesis aims to investigate the
inherent abilities of cellular GAs to deal with SHEs and SEUs at algorithmic level. A
hard real-time application is targeted: calculating the attitude parameters for navigation
in vehicles using Global Positioning System (GPS) technology. Faulty critical
data, which can cause a system’s functionality to fail, are evaluated. The proposed
mitigation techniques show cGAs ability to deal with up to 40% stuck at zero and 30%
stuck at one faults in chromosomes bits and fitness score cells.
Due to the non-deterministic nature of GAs, dynamic on-the-fly algorithmic and
parametric configuration has also attracted the attention of researchers. In this respect,
the structural properties of cellular GAs provide a valuable attribute to influence their
selection pressure. This helps to maintain an adequate exploitation-exploration tradeoff,
either from a pure topological perspective or through genetic operations that also
make use of structural characteristics in cGAs. These properties, unique to cGAs, are
further investigated in this thesis through a set of middle to high difficulty benchmark
problems. Experimental results show that the proposed dynamic techniques enhance
the overall performance of cGAs in most benchmark problems.
Finally, being structurally attached, the dimensionality of cellular GAs is another
line of investigation. 1D and 2D structures have normally been used to test cGAs at
algorithm and implementation levels. Although 3D-cGAs are an immediate extension,
not enough attention has been paid to them, and so a comparative study on the dimensionality
of cGAs is carried out. Having shorter radii, 3D-cGAs present a faster
dissemination of solutions and have denser neighbourhoods. Empirical results reported
in this thesis show that 3D-cGAs achieve better efficiency when solving multi-modal
and epistatic problems. In future, the performance improvements of 3D-cGAs will
merge with the latest benefits that 3D integration technology has demonstrated, such
as reductions in routing length, in interconnection delays and in power consumption
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