• 한국공작기계학회논문집
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• 제17권2호
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• pp.13-22
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• 2008

For the accuracy correction of the micro-positioning industrial robot, micro-manipulator has been devised. The compliant mechanisms using piezoelectric actuators is necessary geometrically and structurally to be developed by the optimization approaches. The overall geometric advantage as the mechanical efficiencies of the mechanism are considered as objective functions, which respectively art the ratio of output displacement to input force, and their constraints are the vertical notion of supporting leg and the structural strength of manipulation. In optimizing the compliant mechanical amplifier, the sequential linear programming and an optimality criteria method are used for the geometrical dimensions of compliant bridges and flexure hinges. This paper presents the integrated design process which not only can maximize the mechanism feasibilities but also can ensure the positioning accuracy and sufficient workspace. Experiment and simulation are presented for validating the design process through the comparisons of the kinematical and structural performances.

• 통합자연과학논문집
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• 제6권2호
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• pp.100-103
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• 2013

Using computational approaches we can dock small molecules into the structures of Macromolecular targets and then score their potential complementarity to binding sites is widely used in hit identification and lead optimization techniques. This review seeks to provide the application of docking in structure-based drug design (binding mode prediction, Lead Identification and Lead optimization), and also discussed how to manage errors in docking methodology in order to overcome certain limitations of docking and scoring algorithm.

• 해양환경안전학회지
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• 제23권3호
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• pp.258-265
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• 2017

This paper validates a system identification method using mathematical optimization using sea trial measurement data as a benchmark. A fast time simulation tool, SIMOPT, and a Rheinmetall Defence mathematical model have been adopted to conduct initial hydrodynamic coefficient estimation and simulate ship modelling. Calibration for the environmental effect of sea trial measurement and sensitivity analysis have been carried out to enable a simple and efficient optimization process. The optimization process consists of three steps, and each step controls different coefficients according to the corresponding manoeuvre. Optimization result of Step 1, an optimization for coefficient on x-axis, was similar compared to values applying an empirical regression formulae by Clarke and Norrbin, which is used for SIMOPT. Results of Steps 2 and 3, which are for linear coefficients and nonlinear coefficients, respectively, was differ from the calculation results of the method by Clarke and Norrbin. A comparison for ship trajectory of simulation results from the benchmark and optimization results indicated that the suggested stepwise optimization method enables a coefficient tuning in a mathematical way.

• 한국해양환경ㆍ에너지학회지
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• 제19권3호
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• pp.194-202
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• 2016

본 연구에서는 10 MW급 부유식 파력-풍력 복합발전 시스템의 플랫폼 초기 개념설계를 위해 유한요소해석 기반 위상 최적화를 검토하였다. 실제 파력-풍력 복합발전 시스템 플랫폼의 위상최적화를 수행하기 전에 단순화된 구조설계 문제를 이용하여 효율적인 위상최적화 이론을 확인하고자 밀도법과 균질화설계법의 두 가지 위상최적화 이론을 적용하였다. 단순화된 설계 문제의 결과로부터 균질화설계법 이론을 파력-풍력 복합발전 시스템의 플랫폼 위상최적화에 적용하였다. 파력-풍력 복합발전 시스템의 플랫폼 개념설계를 위해서 유한요소해석 모델을 생성하고 설치해역의 해양환경하중을 고려하여 구조해석을 수행하였다. 설계파 및 조류와 같은 해양환경하중으로부터 기인하는 플랫폼 상의 압력과 계류삭의 인장력을 산출하기 위하여 동수력학 해석을 수행하였다. 구조해석을 위한 하중조건은 부유체 동수력학 해석으로부터의 결과와 파력-풍력 복합발전 시스템 중량을 고려하였고, 경계조건은 관성제거법을 사용하여 구현하였다. 밀도법 기반 파력-풍력 복합발전 시스템 플랫폼의 위상최적화 결과로부터 개념설계 단계에서 주요 구조부재의 배치방안을 제시하였다. 본 연구결과로부터 위상최적화는 부유식 파력-풍력 복합발전 시스템과 같은 새로운 형식의 해양구조물 개발에 있어서 주요 구조부재 배치의 개념설계에 대해 유용한 설계도구임을 확인하였다.

• 한국정보통신설비학회:학술대회논문집
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• 한국정보통신설비학회 2006년도 하계학술대회
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• pp.39-42
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• 2006

There are various analysis functions(including prediction of path loss, analyzing of capacity and coverage, etc.) of simulation tool to design and optimize the mobile communication network. Its reliability absolutely effects the performance of mobile communication network. Especially as the wireless network highly advancing focused on data service, it more needs to research and develop on the standard establishment of reliability of the simulation tool. Also it is important the systematic research how to improve the reliability of simulation tool. In this paper, to give the concrete process and skill about how to improve reliability, we define the kinds of reliability at first. And then we explain the comparison results between real field measurement data and theoretic simulation data.

• Journal of Computational Design and Engineering
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• 제3권3호
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• pp.266-273
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• 2016

Optimization of hole-making operations in manufacturing industry plays a vital role. Tool travel and tool switch planning are the two major issues in hole-making operations. Many industrial applications such as moulds, dies, engine block, automotive parts etc. requires machining of large number of holes. Large number of machining operations like drilling, enlargement or tapping/reaming are required to achieve the final size of individual hole, which gives rise to number of possible sequences to complete hole-making operations on the part depending upon the location of hole and tool sequence to be followed. It is necessary to find the optimal sequence of operations which minimizes the total processing cost of hole-making operations. In this work, therefore an attempt is made to reduce the total processing cost of hole-making operations by applying relatively new optimization algorithms known as shuffled frog leaping algorithm and proposed modified shuffled frog leaping algorithm for the determination of optimal sequence of hole-making operations. An industrial application example of ejector plate of injection mould is considered in this work to demonstrate the proposed approach. The obtained results by the shuffled frog leaping algorithm and proposed modified shuffled frog leaping algorithm are compared with each other. It is seen from the obtained results that the results of proposed modified shuffled frog leaping algorithm are superior to those obtained using shuffled frog leaping algorithm.

• 한국기계가공학회지
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• 제16권2호
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• pp.7-15
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• 2017

Recently, an electricity sensor system has been installed and operated to prevent failures and accidents by identifying whether a transformer is normal in advance of failure. This electricity sensor system is able to both measure and monitor the transformer's power and voltage remotely and send information to a manager when unusual operation is discovered. However, a battery is required to operate power detection devices, and battery systems need ongoing management such as regular replacement. In addition, at a maintenance cost, occasional human resources and worker safety problems arise. Accordingly, we apply a linear electromagnetic generator using vibration energy from a transformer for an electric sensor system's drive in this research and we conduct optimal design to maximize the linear electromagnetic generator's power. We consider design variables using the provided design method from Process Integration, Automation, and Optimization (PIAnO), which is common tool from process integration and design optimization (PIDO). In addition, we analyze the experiment point from the design of the experiments using "MAXWELL," which is a common electromagnet analysis program. We then create an approximate model and conduct accuracy verification. Finally, we determine the optimal model that generates the maximum power using the proven approximate kriging model and evolutionary optimization algorithm, which we then confirm via simulation.

• 반도체디스플레이기술학회지
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• 제15권4호
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• pp.86-91
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• 2016

End milling is an important and common machining operation because of its versatility and capability to produce various profiles and curved surfaces. This paper presents an experimental study of the cutting force variations in the end milling of SM25C with HSS(high speed steel) and carbide tool. This paper involves a study of the Taguchi design application to optimize cutting force in a end milling operation. The Taguchi design is an efficient and effective experimental method in which a response variable can be optimized, given various control and noise factors, using fewer resources than a factorial design. This study included feed rate, spindle speed and depth of cut as control factors, and the noise factors were different cutting tool in the same specification. An orthogonal array of $L_9(3^3)$ of ANOVA analyses were carried out to identify the significant factors affecting cutting force, and the optimal cutting combination was determined by seeking the best cutting force and signal-to-noise ratio. Finally, confirmation tests verified that the Taguchi design was successful in optimizing end milling parameters for cutting force.

• 한국기계가공학회지
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• 제12권4호
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• pp.114-122
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• 2013

This study introduces an optimization methodology for the determination of gate location that ensures the melt flow balance within a part cavity of injection mold. A new sequential direct-search scheme based on the recursive reduction of the designer-specified gate design area is developed, and it is integrated with a commercial flow simulation tool for optimization. To quantify the level of melt flow balance, we employ the maximum difference among the fill times for the melt fronts to reach the boundary elements of part cavity as objective function. The proposed methodology is successfully applied in the case study of melt flow balancing in molding of a bar code scanner model. The result shows that the melt flow balance at the optimized gate positions is significantly improved from that for the initial gate position.

• 한국정밀공학회지
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• 제26권4호
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• pp.120-127
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• 2009

Spindle units of machine tool are very important part in the manufacturing area. Recently high speed machining has become the main issue of metal cutting. To develop high speed machine tools, a lot of studies have been carried out for high speed spindle. Due to increase of the rotational speed of the spindle, there has been renewal of interest in vibration of spindle. This paper concerns the improvement of spindle design using design of experiments. To improve the design of critical speed and weight of spindle, the experiments using central composite method have been carried out. The targets are critical speed and weight of spindle. For optimization of critical speed and weight and optimization of only critical speed by operation of all area search through response optimizer, the result of analysis has improved design of each factor. Finite element analyses are performed by using the commercial codes ARMD, CATIA V5 and ANSYS workbench. From the results, it has been shown that the proposed method is effective for modification of spindle design to improve critical speed and weight.