In order to design full-envelop flight control law for a certain helicopter, a novel method based on multi-objective genetic algorithm (MOGA) is put forward. In this method, the design of flight control law is viewed ...
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ISBN:
(纸本)9780819473622
In order to design full-envelop flight control law for a certain helicopter, a novel method based on multi-objective genetic algorithm (MOGA) is put forward. In this method, the design of flight control law is viewed as a multi-objective optimization problem(MOP) where obtaining optimal performances in each designed flight envelop are treated as sub-objective and that in all designed flight envelop as objective, flight control law's parameters to be searched as decision variables, corresponding performance criteria as constraints. For the MOP, MOGA is used to get the optimal parameters of flight control law in all designed flight envelops. Finally, the novel method is applied to the flight control law's design for the helicopter's pitch motion, the simulation results show that the parameters are feasible and the performances are satisfactory, which further prove that the method is effective.
This paper covers an investigation on the effects of diversity control in the search performances of single-objective and multi-objective genetic algorithms. The diversity control is achieved by means of eliminating d...
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This paper covers an investigation on the effects of diversity control in the search performances of single-objective and multi-objective genetic algorithms. The diversity control is achieved by means of eliminating duplicated individuals in the population and dictating the survival of non-elite individuals via either a deterministic or a stochastic selection scheme. In the case of single-objectivegeneticalgorithm, onemax and royal road R-1 functions are used during benchmarking. In contrast, various multi-objective benchmark problems with specific characteristics are utilised in the case of multi-objective genetic algorithm. The results indicate that the use of diversity control with a correct parameter setting helps to prevent premature convergence in single-objective optimisation. Furthermore, the use of diversity control also promotes the emergence of multi-objective solutions that are close to the true Pareto optimal solutions while maintaining a uniform solution distribution along the Pareto front.
In this paper, optimal corrective control actions are presented to restore the secure operation of power system for different operating conditions. geneticalgorithm (GA) is one of the modern optimization techniques, ...
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ISBN:
(纸本)9781905593361
In this paper, optimal corrective control actions are presented to restore the secure operation of power system for different operating conditions. geneticalgorithm (GA) is one of the modern optimization techniques, which has been successfully applied in various areas in power systems. Most of the corrective control actions involve simultaneous optimization of several objective functions, which are competing and conflicting each other. The multi-objective genetic algorithm (MOGA) is used to optimize. the corrective control actions. Three different procedures based on GA and MOGA are proposed to alleviate the violations of the overloaded lines and minimize the transmission line losses. The first procedure is based on corrective switching of the transmission lines and generation re-dispatch. The second procedure is carried out to determine the optimal siting and sizing of distributed generation (DG). While, the third procedure is concerned into solving the generation-load imbalance problem using load shedding. Numerical simulations are carried out on two test systems in order to examine the validity of the proposed procedures.
In order to facilitate the tryout or simulation process at the end of a manual auto panel drawing die face design process, we use finite element analysis (FEA) and a multi-objective genetic algorithm (MOGA) to find al...
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In order to facilitate the tryout or simulation process at the end of a manual auto panel drawing die face design process, we use finite element analysis (FEA) and a multi-objective genetic algorithm (MOGA) to find all the Pareto optimal solutions in one go and to achieve the optimal design of an auto panel drawing die face instead of transforming multi-objective functions into a single objective function, and employ a novel mesh morphing technique to achieve fast modification of parametric or non-parametric addendum surfaces and binder surfaces on drawing die faces without going back to CAD for reconstruction of geometric models or to FEA for remodeling. We use an auto panel drawing die face design process as an example to illustrate the application and effectiveness of this proposed approach, and come to the conclusion that the proposed approach is more effective than the traditional manual FEA method and the 'trial-and-error' approach in optimizing an auto panel drawing die face design. (c) 2007 Elsevier Ltd. All rights reserved.
The optimization of time-fixed linearized impulsive rendezvous with control uncertainty is investigated. One performance index related to the variances of the terminal state error is defined as the performance index o...
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The optimization of time-fixed linearized impulsive rendezvous with control uncertainty is investigated. One performance index related to the variances of the terminal state error is defined as the performance index of robustness which is calculated by linear covariance method. The two-objective optimization problem of minimizing the total characteristic velocity and the performance index of robustness is formulated based on the Clohessy-Wiltshire (C-W) system and solved by the nondominated sorting geneticalgorithm. The Pareto-optimal solution sets of one homing rendezvous mission are provided and the Pareto optimality is verified by comparing with the fuel-optimal and the robustness-optimal solutions. It is shown that the proposed approach can quickly investigate the relation between the fuel cost and the trajectory robustness, besides evaluate different rendezvous maneuver schemes. (c) 2007 Elsevier Masson SAS. All rights reserved.
In this paper, a mixed-model assembly line (MMAL) sequencing problem is studied. This type of production system is used to manufacture multiple products along a single assembly line while maintaining the least possibl...
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In this paper, a mixed-model assembly line (MMAL) sequencing problem is studied. This type of production system is used to manufacture multiple products along a single assembly line while maintaining the least possible inventories. With the growth in customers' demand diversification, mixed-model assembly lines have gained increasing importance in the field of management. Among the available criteria used to judge a sequence in MMAL, the following three are taken into account: the minimization of total utility work, total production rate variation, and total setup cost. Due to the complexity of the problem, it is very difficult to obtain optimum solution for this kind of problems by means of traditional approaches. Therefore, a hybrid multi-objectivealgorithm based on shuffled frog-leaping algorithm (SFLA) and bacteria optimization (BO) are deployed. The performance of the proposed hybrid algorithm is then compared with three well-known geneticalgorithms, i.e. PS-NC GA, NSGA-II, and SPEA-II. The computational results show that the proposed hybrid algorithm outperforms the existing geneticalgorithms, significantly in large-sized problems. (c) 2007 Elsevier Ltd. All rights reserved.
The sequencing of products for mixed-model assembly line in Just-in-Time manufacturing systems is sometimes based on multiple criteria. In this paper, three major goals are to be simultaneously minimized: total utilit...
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The sequencing of products for mixed-model assembly line in Just-in-Time manufacturing systems is sometimes based on multiple criteria. In this paper, three major goals are to be simultaneously minimized: total utility work, total production rate variation, and total setup cost. A multi-objective sequencing problem and its mathematical formulation are described. Due to the NP-hardness of the problem, a new multi-objective particle swarm (MOPS) is designed to search locally Pareto-optimal frontier for the problem. To validate the performance of the proposed algorithm, various test problems are solved and the reliability of the proposed algorithm, based on some comparison metrics, is compared with three distinguished multi-objective genetic algorithms (MOGAs), i.e. PS-NC GA, NSGA-II, and SPEA-II. Comparison shows that MOPS provides superior results to MOGAs.
The effectiveness of a supervisory fuzzy control technique for reduction of seismic response of a smart base isolation system is investigated in this study. To this end, a first generation, base isolated, benchmark bu...
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The effectiveness of a supervisory fuzzy control technique for reduction of seismic response of a smart base isolation system is investigated in this study. To this end, a first generation, base isolated, benchmark building is employed for numerical simulation. The benchmark structure under consideration has eight stories and an irregular plan. Furthermore it is equipped with low damping elastomeric bearings and magnetorheological (MR) dampers for seismic protection. The proposed control technique employs a hierarchical structure of fuzzy logic controllers (FLC) consisting of two lower-level controllers (sub-FLC) and a higher-level supervisory controller. One sub-FLC has been optimized for near-fault earthquakes and the other sub-FLC is well-suited for far-fault earthquakes. These sub-FLCs are optimized by use of a multi-objective genetic algorithm. Four objectives, i.e. reduction of peak superstructure acceleration, peak isolation system deformation, RMS superstructure acceleration and RMS isolation system deformation are used in a multi-objective optimization process. When an earthquake is applied to the benchmark building, each of the sub-FLCs provides different command voltages for the semi-active controllers and the supervisory fuzzy controller appropriately combines the two command voltages based on a fuzzy inference system in real time. Results from numerical simulations demonstrate that isolation system deformation as well as superstructure responses can be effectively reduced using the proposed supervisory fuzzy control technique in comparison with a sample clipped optimal controller. (C) 2006 Elsevier Ltd. All rights reserved.
multi-objective genetic algorithm based on Pareto optimum is much suitable for solving multi-objective optimization problems. The relations between individuals and some features about these relations are discussed. It...
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multi-objective genetic algorithm based on Pareto optimum is much suitable for solving multi-objective optimization problems. The relations between individuals and some features about these relations are discussed. It is proved that the individuals of an evolutionary population can be classified by the idea of quick sort. At the same time, the approach to maintain diversity of solutions by clustering algorithms is discussed, and the clustering algorithm based on hierarchical aggregation is also discussed. Then by using the quick sort algorithm and the clustering procedure, an algorithm of constructing a new evolutionary population is proposed. It is shown by theoretic analysis and experimental results that the convergent speed of the algorithm discussed is more efficient than the other existing algorithms.
Flow shop problems as a typical manufacturing challenge have gained wide attention in academic fields. In this paper, we consider a bi-criteria permutation flow shop scheduling problem, where weighted mean completion ...
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Flow shop problems as a typical manufacturing challenge have gained wide attention in academic fields. In this paper, we consider a bi-criteria permutation flow shop scheduling problem, where weighted mean completion time and weighted mean tardiness are to be minimized simultaneously. Since a flow shop scheduling problem has been proved to be NP-hard in strong sense, an effective multi-objective particle swarm (MOPS), exploiting a new concept of the Ideal Point and a new approach to specify the superior particle's position vector in the swarm, is designed and used for finding locally Pareto-optimal frontier of the problem. To prove the efficiency of the proposed algorithm, various test problems are solved and the reliability of the proposed algorithm, based on some comparison metrics, is compared with a distinguished multi-objective genetic algorithm, i.e. SPEA-II. The computational results show that the proposed MOPS performs better than the geneticalgorithm, especially for the large-sized problems.
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