Since multi-objective optimizations are becoming more important in engine calibration, the paper investigates multi-objective genetic algorithms in the application of engine optimization. Although several multi-object...
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Since multi-objective optimizations are becoming more important in engine calibration, the paper investigates multi-objective genetic algorithms in the application of engine optimization. Although several multi-objective genetic algorithms have been developed and some have been applied successfully in the automotive industry, it is difficult to determine which multi-objectivegenetic algorithm outperforms others in finding the set of optimal solutions or Pareto-optimal front in a practical multi-objective optimization problem. Based on some widely used multi-objective genetic algorithms, the paper proposes a combined scheme to deal with the difficulties in finding the optimal solution set during the engine calibration process. In the proposed approach the real-coded representation is employed in the genetic algorithm and the elitist strategy is applied for each multi-objectivegenetic algorithm used. To assess the proposed approach, two computational examples are given to minimize the brake specific fuel consumption and to maximize the output power torque simultaneously. The results show that the proposed approach is well suited to multi-objective optimization in engine calibration.
A significant class of decision making problems consists of choosing actions, to be carried out simultaneously, in order to achieve a trade-off between different objectives. When such decisions concern complex systems...
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A significant class of decision making problems consists of choosing actions, to be carried out simultaneously, in order to achieve a trade-off between different objectives. When such decisions concern complex systems, decision support tools including formal methods of reasoning and probabilistic models are of noteworthy helpfulness. These models are often built through learning procedures, based on an available knowledge base. Nevertheless, in many fields of application (e.g. when dealing with complex political, economic and social systems), it is frequently not possible to determine the model automatically, and this must then largely be derived from the opinions and value judgements expressed by domain experts. The BayMODE decision support tool (Bayesian multiobjective Decision Environment), which we describe in this paper, operates precisely in such contexts. The principal component of the program is a multi-objective Decision Network, where actions are executed simultaneously. If the noisy-OR assumptions are applicable, such a the model has a reasonably small number of parameters, even when actions are represented as non-binary variables. This makes the model building procedure accessible and easy. Moreover, BayMODE operates with a multi-objective approach, which provides the decision maker with a set of non-dominated solutions, computed using a multi-objectivegenetic algorithm.
multi-objective genetic algorithms (MOGAs) are finding increasing popularity as researchers realize their potential for obtaining good solutions to mining problems in large databases. Parallel multi-objectivegenetic ...
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multi-objective genetic algorithms (MOGAs) are finding increasing popularity as researchers realize their potential for obtaining good solutions to mining problems in large databases. Parallel multi-objective genetic algorithms (pMOGAs) attempts to reduce the processing time needed for computing the fitness functions and to reach an acceptable solution. We propose two different master slave models of pMOGA. Our proposed models exploit both data parallelism by distributing the data being mined across various processors, and control parallelism by distributing the population of individuals across all available processors. These models are implemented through a cluster computing environment and we measure the speed up of pMOGA over its sequential counterpart.
This work proposes the application of multi-objective genetic algorithms to obtain Fuzzy Rule-Based Systems with a better trade-off between interpretability and accuracy in linguistic fuzzy modelling problems. To do t...
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This work proposes the application of multi-objective genetic algorithms to obtain Fuzzy Rule-Based Systems with a better trade-off between interpretability and accuracy in linguistic fuzzy modelling problems. To do that, we present a new post-processing method that by considering selection of rules together with the tuning of membership functions gets solutions only in Pareto zone with the highest accuracy. This method is based on the well-known SPEA2 algorithm, applying approriate genetic operators and including some modifications to concentrate the search in the desired Pareto zone.
作者:
Kaya, MehmetFirat Univ
Dept Comp Engn Data Min & Bioinformat Lab TR-23119 Elazig Turkey
We propose an efficient method using multi-objectivegenetic algorithm (MOGAMOD) to discover optimal motifs in sequential data. The main advantage of our approach is that a large number of tradeoff (i.e., nondorr nate...
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ISBN:
(纸本)9783540748243
We propose an efficient method using multi-objectivegenetic algorithm (MOGAMOD) to discover optimal motifs in sequential data. The main advantage of our approach is that a large number of tradeoff (i.e., nondorr nated) motifs can be obtained by a single run with respect to conflicting objectives: similarity, motif length and support maximization, To the best of our knowledge, this is the first effort in this direction. MOGAMOD can be applied to any data set with a sequential character, Furthermore, it allows any choice of similarity measures for finding motifs. By analyzing the obtained optimal motifs, the decision maker can understand the tradeoff between the objectives. We compare MOGAMOD with the three well-known motif discovery methods, AlignACE, MEME and Weeder. Experimental results on real data set extracted from TRANSFAC database demonstrate that the proposed method exhibits good performance over the other methods in terms of runtime, the number of shaded samples and multiple motifs.
Availability allocation is required when the manufacturer is obliged to allocate proper availability to various components in order to design an end product to meet specified requirements. This paper proposes a new mu...
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Availability allocation is required when the manufacturer is obliged to allocate proper availability to various components in order to design an end product to meet specified requirements. This paper proposes a new multi-objectivegenetic algorithm, namely simulated annealing based multi-objectivegenetic algorithm (saMOGA), to resolve the availability allocation and optimization problems of a repairable system, specifically a parallel-series system. Compared with a general multi-objectivegenetic algorithm, the major feature of the saMOGA is that it can accept a poor solution with a small probability in order to enlarge the searching space and avoid the local optimum. The saMOGA aims to determine the optimal decision variables, i.e. failure rates, repair rates, and the number of components in each subsystem, according to multiple objectives, such as system availability, system cost and system net profit. The proposed saMOGA is compared with three other multi-objective genetic algorithms. Computational results showed that the proposed approach could provide higher solution quality and greater computing efficiency. (c) 2006 Elsevier B.V. All rights reserved.
This paper presents an optimization investigation on methanol synthesis reactor in the face of catalyst deactivation using multi-objective genetic algorithms. Catalyst deactivation is a challenging problem in the oper...
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This paper presents an optimization investigation on methanol synthesis reactor in the face of catalyst deactivation using multi-objective genetic algorithms. Catalyst deactivation is a challenging problem in the operation of methanol synthesis reactor and has an important role on productivity of the reactor. Therefore, determination of the optimal temperature profile along the reactor could be a very important effort in order to cope with catalyst deactivation. Our previous studies clarify the benefits of a two-stage reactor over a single stage reactor. In this study, an optimal temperature trajectory is obtained for each stage of the corresponding two-stage reactor. Here, steady state optimization is performed in six different activity levels by maximizing the yield and minimizing the temperature of the first stage of the reactor. multi-objective genetic algorithms are used to solve this two-objective optimization. The set of optimal solutions obtained for six activity levels represents an optimal temperature trajectory for each stage, which has been extended and proposed as adynamic optimization. This optimization resulted in an additional 3.6% yield, during the course of 4-year process. (c) 2006 Elsevier B.V. All rights reserved.
This paper is concerned with the multi-objective Next Release Problem (MONRP), a problem in search-based requirements engineering. Previous work has considered only single objective formulations. In the multi-objectiv...
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ISBN:
(纸本)9781595936974
This paper is concerned with the multi-objective Next Release Problem (MONRP), a problem in search-based requirements engineering. Previous work has considered only single objective formulations. In the multi-objective formulation, there are at least two (possibly conflicting) objectives that, the software engineer wishes to optimize. It is argued that the multi-objective formulation is more realistic, since requirements engineering is characterised by the presence of many complex and conflicting demands, for which the software engineer must find a suitable balance. The paper presents the results of ail empirical study into the suitability of weighted and Pareto optimal geneticalgorithms, together with the NSCA-II algorithm, presenting evidence to support the claim that NSGA-II is well suited to the MONRP. The paper also provides benchmark data to indicate the size above which the MONRP becomes non-trivial.
There has been a considerable body of work on search-based test;data, generation for branch coverage. However, hitherto, there has been no work on multi-objective branch coverage. In many scenarios a single-objective ...
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ISBN:
(纸本)9781595936974
There has been a considerable body of work on search-based test;data, generation for branch coverage. However, hitherto, there has been no work on multi-objective branch coverage. In many scenarios a single-objective formulation is unrealistic: testers will want, to find test;sets that meet. several objectives simultaneously in order to maximize the value obtained front the inherently expensive process of running the test, cases and examining the output they produce. This paper introduces multi-objective branch coverage. The paper presents results front a case study of the twin objectives of branch coverage, and dynamic memory consumption for both real and synthetic programs. Several multi-objective evolutionary algorithms are applied. The results show that multiobjective evolutionary algorithms are Suitable for this problem, and illustrates the way in which a Pareto optimal search can yield insights into the trade-offs between the two simultaneous objectives.
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