• 제목/요약/키워드: Hybrid genetic operators

검색결과 17건 처리시간 0.021초

조기수렴 저감을 위한 해밍거리와 적합도의 혼합 유전 연산자 (Hybrid Genetic Operators of Hamming Distance and Fitness for Reducing Premature Convergence)

  • 이홍규
    • 한국항행학회논문지
    • /
    • 제18권2호
    • /
    • pp.170-177
    • /
    • 2014
  • 유전 알고리즘은 강인한 탐색과 최적화 기술이기는 하나 조기 수렴과 국부 최적해에 수렴하는 문제점들을 내포하고 있다. 모집단의 다양성이 작은 값으로 수렴할수록 탐색능력이 감소하고, 국부 최적해에 수렴하지만, 모집단의 다양성이 높은 값으로 수렴할수록 탐색능력이 증가하고 전역 최적해에 수렴할 수 있으나 유전 알고리즘은 발산할 수도 있다. 유전 알고리즘이 전역 최적해에 수렴하는 것을 보장하기 위해서는 유전 연산자가 적절하게 선정되어야 한다. 본 논문에서는 조기 수렴으로부터 벗어나기 위하여 모집단의 다양성을 유지하도록 평균해밍거리와 적합도 값을 혼합한 함수를 이용한 유전 연산자들을 제안하였다. 모의실험을 통하여 다양성의 유지를 위한 돌연변이 연산자와 수렴 특성의 향상을 위한 다른 유전자들의 효과를 확인할 수 있었으며, 본 논문에서 제안한 유전 연산자들이 조기 수렴이나 국부 최적해에 수렴하는 경우를 피하는데 유용한 방법임이 확인되었다.

레이저 토치의 절단경로 생성을 위한 혼합형 유전알고리즘 (A Hybrid Genetic Algorithm for Generating Cutting Paths of a Laser Torch)

  • 이문규;권기범
    • 제어로봇시스템학회논문지
    • /
    • 제8권12호
    • /
    • pp.1048-1055
    • /
    • 2002
  • The problem of generating torch paths for 2D laser cutting of a stock plate nested with a set of free-formed parts is investigated. The objective is to minimize the total length of the torch path starting from a blown depot, then visiting all the given Parts, and retuning back to the depot. A torch Path consists of the depot and Piercing Points each of which is to be specified for cutting a part. The torch path optimization problem is shown to be formulated as an extended version of the standard travelling salesman problem To solve the problem, a hybrid genetic algorithm is proposed. In order to improve the speed of evolution convergence, the algorithm employs a genetic algorithm for global search and a combination of an optimization technique and a genetic algorithm for local optimization. Traditional genetic operators developed for continuous optimization problems are used to effectively deal with the continuous nature of piercing point positions. Computational results are provided to illustrate the validity of the proposed algorithm.

병렬의 동일기계에서 처리되는 순서의존적인 작업들의 스케쥴링을 위한 유전알고리즘 (A Genetic Algorithm for Scheduling Sequence-Dependant Jobs on Parallel Identical Machines)

  • 이문규;이승주
    • 대한산업공학회지
    • /
    • 제25권3호
    • /
    • pp.360-368
    • /
    • 1999
  • We consider the problem of scheduling n jobs with sequence-dependent processing times on a set of parallel-identical machines. The processing time of each job consists of a pure processing time and a sequence-dependent setup time. The objective is to maximize the total remaining machine available time which can be used for other tasks. For the problem, a hybrid genetic algorithm is proposed. The algorithm combines a genetic algorithm for global search and a heuristic for local optimization to improve the speed of evolution convergence. The genetic operators are developed such that parallel machines can be handled in an efficient and effective way. For local optimization, the adjacent pairwise interchange method is used. The proposed hybrid genetic algorithm is compared with two heuristics, the nearest setup time method and the maximum penalty method. Computational results for a series of randomly generated problems demonstrate that the proposed algorithm outperforms the two heuristics.

  • PDF

Hybrid genetic-paired-permutation algorithm for improved VLSI placement

  • Ignatyev, Vladimir V.;Kovalev, Andrey V.;Spiridonov, Oleg B.;Kureychik, Viktor M.;Ignatyeva, Alexandra S.;Safronenkova, Irina B.
    • ETRI Journal
    • /
    • 제43권2호
    • /
    • pp.260-271
    • /
    • 2021
  • This paper addresses Very large-scale integration (VLSI) placement optimization, which is important because of the rapid development of VLSI design technologies. The goal of this study is to develop a hybrid algorithm for VLSI placement. The proposed algorithm includes a sequential combination of a genetic algorithm and an evolutionary algorithm. It is commonly known that local search algorithms, such as random forest, hill climbing, and variable neighborhoods, can be effectively applied to NP-hard problem-solving. They provide improved solutions, which are obtained after a global search. The scientific novelty of this research is based on the development of systems, principles, and methods for creating a hybrid (combined) placement algorithm. The principal difference in the proposed algorithm is that it obtains a set of alternative solutions in parallel and then selects the best one. Nonstandard genetic operators, based on problem knowledge, are used in the proposed algorithm. An investigational study shows an objective-function improvement of 13%. The time complexity of the hybrid placement algorithm is O(N2).

대칭 순회 판매원문제를 위한 Subtour 보존 교차 연산자 (Subtour Preservation Crossover Operator for the Symmetric TSP)

  • 석상문;이홍걸;변성철
    • 대한산업공학회지
    • /
    • 제33권2호
    • /
    • pp.201-212
    • /
    • 2007
  • Genetic algorithms (GAs) are very useful methods for global search and have been applied to various optimization problems. They have two kinds of important search mechanisms, crossover and mutation. Because the performance of GAs depends on these operators, a large number of operators have been developed for improving the performance of GAs. Especially, many researchers have been more interested in a crossover operator than a mutation operator. The reason is that a crossover operator is a main search operator in GAs and it has a more effect on the search performance. So, we also focus on a crossover operator. In this paper we first investigate the drawback of various crossovers, especially subtour-based crossovers and then introduce a new crossover operator to avoid such drawback and to increase efficiency. Also we compare it with several crossover operators for symmetric traveling salesman problem (STSP) for showing the performance of the proposed crossover. Finally, we introduce an efficient simple hybrid genetic algorithm using the proposed operator and then the quality and efficiency of the obtained results are discussed.

Shipyard Skid Sequence Optimization Using a Hybrid Genetic Algorithm

  • Min-Jae Choi;Yung-Keun Kwon
    • 한국컴퓨터정보학회논문지
    • /
    • 제28권12호
    • /
    • pp.79-87
    • /
    • 2023
  • 본 연구는 조선소 소조립 공정에서 스키드 투입 순서 최적화를 통해 전체 작업시간을 단축시키는 새로운 유전 알고리즘 방법을 제안한다. 하나의 해는 스키드 번호들의 순열로 표현되며 그러한 표현에 적합한 유전 연산자들을 적용하였다. 또한 탐색 성능의 개선을 위해 UniDev라 불리우는 기존의 휴리스틱 알고리즘을 적절하게 변형하여 유전 알고리즘과 결합하였다. 특히 UniDev에서 느린 스키드 탐색 부분을 그리디 알고리즘의 형태로 변경하였다. 매우 큰 규모의 문제에 대해 시뮬레이션을 수행한 결과 Multi-Start 탐색과 UniDev기반 혼합형 유전알고리즘에 비해 본 연구에서 제안하는 방법이 안정적으로 작업시간을 최소화함을 관찰하였다.

Particle Swarm Assisted Genetic Algorithm for the Optimal Design of Flexbeam Sections

  • Dhadwal, Manoj Kumar;Lim, Kyu Baek;Jung, Sung Nam;Kim, Tae Joo
    • International Journal of Aeronautical and Space Sciences
    • /
    • 제14권4호
    • /
    • pp.341-349
    • /
    • 2013
  • This paper considers the optimum design of flexbeam cross-sections for a full-scale bearingless helicopter rotor, using an efficient hybrid optimization algorithm based on particle swarm optimization, and an improved genetic algorithm, with an effective constraint handling scheme for constrained nonlinear optimization. The basic operators of the genetic algorithm, of crossover and mutation, are revisited, and a new rank-based multi-parent crossover operator is utilized. The rank-based crossover operator simultaneously enhances both the local, and the global exploration. The benchmark results demonstrate remarkable improvements, in terms of efficiency and robustness, as compared to other state-of-the-art algorithms. The developed algorithm is adopted for two baseline flexbeam section designs, and optimum cross-section configurations are obtained with less function evaluations, and less computation time.

다목적 시뮬레이션 통합 하이브리드 유전자 알고리즘을 사용한 수동 조립라인의 동기 작업 모델 (A Synchronized Job Assignment Model for Manual Assembly Lines Using Multi-Objective Simulation Integrated Hybrid Genetic Algorithm (MO-SHGA))

  • 무하마드 임란;강창욱
    • 산업경영시스템학회지
    • /
    • 제40권4호
    • /
    • pp.211-220
    • /
    • 2017
  • The application of the theoretical model to real assembly lines has been one of the biggest challenges for researchers and industrial engineers. There should be some realistic approach to achieve the conflicting objectives on real systems. Therefore, in this paper, a model is developed to synchronize a real system (A discrete event simulation model) with a theoretical model (An optimization model). This synchronization will enable the realistic optimization of systems. A job assignment model of the assembly line is formulated for the evaluation of proposed realistic optimization to achieve multiple conflicting objectives. The objectives, fluctuation in cycle time, throughput, labor cost, energy cost, teamwork and deviation in the skill level of operators have been modeled mathematically. To solve the formulated mathematical model, a multi-objective simulation integrated hybrid genetic algorithm (MO-SHGA) is proposed. In MO-SHGA each individual in each population acts as an input scenario of simulation. Also, it is very difficult to assign weights to the objective function in the traditional multi-objective GA because of pareto fronts. Therefore, we have proposed a probabilistic based linearization and multi-objective to single objective conversion method at population evolution phase. The performance of MO-SHGA is evaluated with the standard multi-objective genetic algorithm (MO-GA) with both deterministic and stochastic data settings. A case study of the goalkeeping gloves assembly line is also presented as a numerical example which is solved using MO-SHGA and MO-GA. The proposed research is useful for the development of synchronized human based assembly lines for real time monitoring, optimization, and control.

A Hybrid Optimized Deep Learning Techniques for Analyzing Mammograms

  • Bandaru, Satish Babu;Deivarajan, Natarajasivan;Gatram, Rama Mohan Babu
    • International Journal of Computer Science & Network Security
    • /
    • 제22권10호
    • /
    • pp.73-82
    • /
    • 2022
  • Early detection continues to be the mainstay of breast cancer control as well as the improvement of its treatment. Even so, the absence of cancer symptoms at the onset has early detection quite challenging. Therefore, various researchers continue to focus on cancer as a topic of health to try and make improvements from the perspectives of diagnosis, prevention, and treatment. This research's chief goal is development of a system with deep learning for classification of the breast cancer as non-malignant and malignant using mammogram images. The following two distinct approaches: the first one with the utilization of patches of the Region of Interest (ROI), and the second one with the utilization of the overall images is used. The proposed system is composed of the following two distinct stages: the pre-processing stage and the Convolution Neural Network (CNN) building stage. Of late, the use of meta-heuristic optimization algorithms has accomplished a lot of progress in resolving these problems. Teaching-Learning Based Optimization algorithm (TIBO) meta-heuristic was originally employed for resolving problems of continuous optimization. This work has offered the proposals of novel methods for training the Residual Network (ResNet) as well as the CNN based on the TLBO and the Genetic Algorithm (GA). The classification of breast cancer can be enhanced with direct application of the hybrid TLBO- GA. For this hybrid algorithm, the TLBO, i.e., a core component, will combine the following three distinct operators of the GA: coding, crossover, and mutation. In the TLBO, there is a representation of the optimization solutions as students. On the other hand, the hybrid TLBO-GA will have further division of the students as follows: the top students, the ordinary students, and the poor students. The experiments demonstrated that the proposed hybrid TLBO-GA is more effective than TLBO and GA.

A Novel Algorithm for Optimal Location of FACTS Devices in Power System Planning

  • Kheirizad, Iraj;Mohammadi, Amir;Varahram, Mohammad Hadi
    • Journal of Electrical Engineering and Technology
    • /
    • 제3권2호
    • /
    • pp.177-183
    • /
    • 2008
  • The particle swarm optimization(PSO) has been shown to converge rapidly during the initial stages of a global search, but around global optimum, the search process becomes very slow. On the other hand, the genetic algorithm is very sensitive to the initial population. In fact, the random nature of the GA operators makes the algorithm sensitive to initial population. This dependence to the initial population is in such a manner that the algorithm may not converge if the initial population is not well selected. In this paper, we have proposed a new algorithm which combines PSO and GA in such a way that the new algorithm is more effective and efficient and can find the optimal solution more accurately and with less computational time. Optimal location of SVC using this hybrid PSO-GA algorithm is found. We have also found the optimal place of SVC using GA and PSO separately and have compared the results. It has been shown that the new algorithm is more effective and efficient. An IEEE 68 bus test system is used for simulation.