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The Pareto fitness genetic algorithm: Test function study. Wei-Ming Chen 2011.11.03. Outline. The Pareto fitness genetic algorithm (PFGA ) Experimental results Performance measures Conclusion. PFGA. Double ranking strategy (DRS )
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The Pareto fitness genetic algorithm: Test function study Wei-Ming Chen 2011.11.03
Outline • The Pareto fitness genetic algorithm (PFGA) • Experimental results • Performance measures • Conclusion
PFGA • Double ranking strategy (DRS) • R’(i) : how many j that solution j performs better than solution i • the DRS of solution i :
PFGA • Population size adaptive density estimation (PADE) • The cell width on i-th dimension Wdi • Wi : the width of the non-inferior cell
PFGA • Each dimension : pieces • Total : near N pieces
PFGA • Fitness function :
PFGA • Selection operation • “binary stochastic sampling without replacement” • Normalizing the fitness of each considered individual by dividing it by the total fitness • Generate R1 => find which individual is there • Generate R2 => find another individual
PFGA • Elitist external set : the set of non-dominated individuals • updated at each generation
Performance measures • some quantitative measures are used to evaluate the trade-off surface fronts (E. Zitzler, K. Deb, L. Thiele, Comparison of multi-objective evolutionary algorithms) • The convergence to the Pareto optimal front. • The distribution and the number of non-dominated solutions found. • The spread of the given set.
Conclusion • A new MOEA design was proposed in this paper!! • a modified ranking strategy, a promising sharing procedure and a new fitness function design • a relatively good performance when dealing with different Pareto front features
Conclusion • Although the MOEA comparison may be useful, we think that the aim of the multi-objective optimization is not to decide which algorithm outperforms the other but how to deal with difficult problems, which genetic operator may be more suitable for which algorithm to solve a given kind of problems, how to extract the best features from the existing approaches and why not to hybridize some of them to provide better problems’ solutions.