• Journal of applied mathematics & informatics
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• 제32권3_4호
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• pp.539-546
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• 2014

This paper introduces the approximation and a proposed method to deal the optimum location network selection problem such that the total cost is minimized. For the proposed method, we derived a feasible solution and the variance. To compare the performances of the approximation and the proposed method, computer simulation is also implemented. The result showed the solutions being optimum with 74% for the proposed method and 57% for the approximation. When the solutions is not optimum, maximum and average deviations are below 4% and 2% respectively. The results indicate a slightly better performance of the proposed method in a certain case.

• 한국소음진동공학회논문집
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• 제12권6호
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• pp.478-487
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• 2002

This paper presents a hybrid method to compute the solutions of an optimization Problem. The present hybrid algorithm is the synthesis of an artificial life algorithm and the random tabu search method. The artificial life algorithm has the most important feature called emergence. The emergence is the result of dynamic interaction among the individuals consisting of the system and is not found in an individual. The conventional artificial life algorithm for optimization is a stochastic searching algorithm using the feature of artificial life. Emergent colonies appear at the optimum locations in an artificial ecology. And the locations are the optimum solutions. We combined the feature of random-tabu search method with the conventional algorithm. The feature of random-tabu search method is to divide any given region into sub-regions. The enhanced artificial life algorithm (EALA) not only converge faster than the conventional artificial life algorithm, but also gives a more accurate solution. In addition, this algorithm can find all global optimum solutions. The enhanced artificial life algorithm is applied to the optimum design of high-speed, short journal bearings and its usefulness is verified through an optimization problem.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 1994년도 가을 학술발표회 논문집
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• pp.9-16
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• 1994

In the discrete optimum design, occasionally, the solutions oscillate between the feasible and the infeasible resions during the series of redesigns of members with discrete sections. This phenomenon may be caused inherently by the discontinuity of variables of commercially available sections in the database. In this paper, in-depth investigation into the oscillation in the discrete optimization and its control has been conducted. When the structure is optimized through element optimization, the oscillation can be divided into two categories, local and global oscillations. An algorithm which controls these phenomena is suggested and numerical examples demonstrate the oscillation in optimum solutions and the effectiveness of the control strategy suggested here.

• Structural Engineering and Mechanics
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• 제73권2호
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• pp.153-165
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• 2020

The effect of soil foundation plays active role in optimum design of steel space frames when included. However, its influence on design can be calculated after a long iterative procedure. So it requires longer computer time and more computational effort if it is done properly. The main purpose of this study is to investigate how these effects can be calculated in more practical way in a shorter time. The effects of semi-rigid column bases are taken into account in optimum design of steel space frames. This study is carried out by using JAYA algorithm which is a novel and practical method based on a single revision equation. The displacement, stress and geometric size constraints are considered in the optimum design. A computer program is coded in MATLAB to achieve corporation with SAP2000-OAPI (Open Application Programming Interface) for optimum solutions. Four different steel space frames including soil structure interaction taken from literature are investigated according to different semi-rigidly supported models depending on different rotational stiffness values. And the results obtained from analyses are compared with the results available in reference studies. The results of the study show that semi-rigidly supported systems in the range of appropriate rotational stiffness values offer practical solutions in a very short time. And close agreement is obtained with the studies on optimum design of steel space frames including soil effect underneath.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 추계학술대회논문집A
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• pp.698-702
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• 2001

This paper presents a combinatorial method to compute the solutions of optimization problem. The present hybrid algorithm is the synthesis of an artificial life algorithm and the random tabu search method. The hybrid algorithm is not only faster than the conventional artificial life algorithm, but also gives a more accurate solution. In addition, this algorithm can find all global optimum solutions. And the enhanced artificial life algorithm is applied to optimum design of high-speed, short journal bearings and the usefuless is verified through this example.

• Steel and Composite Structures
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• 제22권3호
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• pp.521-535
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• 2016

A Harmony Search (HS) and Genetic Algorithms (GA), two powerful metaheuristic search techniques, are used for minimum weight designs of different truss structures by selecting suitable profile sections from a specified list taken from American Institute of Steel Construction (AISC). A computer program is coded in MATLAB interacting with SAP2000-OAPI to obtain solution of design problems. The stress constraints according to AISC-ASD (Allowable Stress Design) and displacement constraints are considered for optimum designs. Three different truss structures such as bridge, dome and tower structures taken from literature are designed and the results are compared with the ones available in literature. The results obtained from the solutions for truss structures show that optimum designs by these techniques are very similar to the literature results and HS method usually provides more economical solutions in multi-element truss problems.

• 인터넷정보학회논문지
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• 제17권3호
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• pp.19-24
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• 2016

최소오차 엔트로피 알고리듬(MEE)은 충격성 잡음 환경에서 성능이 우수한 것으로 알려져 있다. 이 논문에서는 충격성 잡음에 대한 강인성의 견지에서 MEE 알고리듬의 최적해와 특성을 연구하였다. 큰 오차 값의 영향을 경감하는 요인들과 최적 가중치의 움직임에 대한 분석을 통하여 MEE의 최적해가 충격성 잡음으로부터 안정적으로 유지되도록 하는 주된 역할은 크기 조정된 입력 엔트로피가 담당하고 있음이 밝혀졌다. 시뮬레이션 결과에서, MEE의 최적해는 MSE 성능기준의 최적해와 같은 값을 가짐을 보였다.

• Structural Engineering and Mechanics
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• 제68권5호
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• pp.633-638
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• 2018

One of the important problems in the vehicle design is vehicle handling and stability. Effective parameters which should be considered in the vehicle handling and stability are roll angle, camber angle and scrub radius. In this paper, a planar vehicle model is considered that two right and left suspensions are double wishbone suspension system. For a better analysis of the suspension geometry, a kinestatic model of vehicle is considered which instantaneous kinematic and statics relations are analyzed simultaneously. In this model, suspension geometry is considered completely. In order to optimum design of double wishbones suspension system, a multi-objective genetic algorithm is applied. Three important parameters of suspension including roll angle, camber angle and scrub radius are taken into account as objective functions. Coordinates of suspension hard points are design variables of optimization which optimum values of them, corresponding to each optimum point, are obtained in the optimization process. Pareto solutions for three objective functions are derived. There are important optimum points in these Pareto solutions which each point represents an optimum status in the model. In other words, corresponding to any optimal point, a specific geometric position is determined for the suspension hard points. Each of the obtained points in the Pareto optimization can be selected for a special design purpose by designer to create an optimum condition in the vehicle handling and stability.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2004년도 춘계학술대회논문집
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• pp.400-403
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• 2004

This paper presents an optimum design of journal bearings using a hybrid method to find the solutions of optimization problem. The present hybrid algorithm, namely Enhanced Artificial Life Algorithm(EALA), is a synthesis of an artificial life algorithm(ALA) and the random tabu search(R-tabu) method. EALA is applied to the optimum design of journal bearings supporting simple rotor. The applicability of EALA to optimum design of rotor-bearing system is exemplified through this study.

• 대한산업공학회지
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• 제12권2호
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• pp.33-44
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• 1986

This research is concerned with group scheduling problems in multi-stage manufacturing system with dependent setup time. The objective of the research is to develop and evaluate a heuristic algorithm for determining group sequence and job sequence within each group to minimize total tardiness in multi-stage manufacturing systems with sequence dependent group setup time. The group scheduling heuristic algorithm is developed and evaluated by comparisons with twenty-seven problems with the known optimum solutions and 144,000 random schedules of a large variety problems. The results indicate that the proposed heuristic algorithm gets the same optimum solutions for the problems and also provides the good solutions in comparison with the random schedules of the large variety problems. A numerical example is given to illustrate the heuristic algorithm.