• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제55권11호
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• pp.541-546
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• 2006

In a levitation magnet system with large air gap, numerical method is needed because analytic method cannot consider the leakage flux properly. This paper conducted an optimal design of a levitation magnet system with large air gap which was used for an OLED system, where evolution strategy was adopted for optimal design algorithm. Levitation forces near the initial design were calculated first by using finite element method to reduce the computation time. During the optimization process, levitation forces of arbitrary dimension were obtained using the interpolation of the levitation forces which were calculated previously Weight of the maget system was chosen as the object function and it was used minimized.

• 한국기계가공학회지
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• 제11권1호
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• pp.68-75
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• 2012

In this study, the optimal synthesis of planar steering mechanisms for vehicles is studied. The author minimized the steering error between two front wheels subject to the constraints of transmission angles. Nonlinear programming methods such as BFGS method and golden section search method are used for this optimization. As numerical examples, Ackermann's steering mechanism, 6-link and 10-link planar mechanism are adopted to check the usefulness of this method. Consequently, among the three optimized mechanisms, 10-link planar one conducts far more accurate performance subject to tight constraints of transmission angles.

• Journal of Advanced Marine Engineering and Technology
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• 제30권7호
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• pp.800-807
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• 2006

This paper introduces the hull deflection analysis method by using the direct measurements. Accordingly, this paper demonstrates how the hull deflection data is obtained by the reverse calculations using the bending moments from the stain gauge and bearing reactions from jack-up method. Where the hull deflection data provided by this research is used for the shafting alignment calculations for identical or similar vessels, shafting failures due to hull deflections can be minimized. It will also save time and expenses associated finite element method to predict hull deflections.

• 한국공작기계학회논문집
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• 제17권6호
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• pp.35-42
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• 2008

Most of tasks for vertical surface work in shipyard have been accomplished by human workers. However, such manual work often causes injury to workers, also the production cost becomes high due to increasing individual wage. To cope with the circumstance, shipbuilding companies try to introduce wall-climbing robots for carrying out such kind of tasks. In designing a wall-climbing robot, it is essential to minimize its own weight to improve the performance such as moving speed and power saving. For such purpose. this study proposes a method of optimal design for a wall-climbing robot using a genetic algorithm with multi-objective function. Specifically, the thickness of the robot base is minimized to reduce the weight while maintaining the allowable strength and avoiding the resonance frequencies. The proposed method is applied to the design of a wall-climbing robot, and the result shows that the method is useful at an early design stage.

• Bulletin of the Korean Chemical Society
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• 제35권7호
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• pp.1933-1938
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• 2014

Despite increasing importance of in vitro cell-based assays for the assessment of nanoparticles (NPs) cytotoxicity, their suitability for the assessment of NPs toxicity is still in doubt. Here, limitations of widely used cell viability assay protocol (i.e., MTT asssay) for the cytotoxicity assessment of P25 $TiO_2$ NPs were carefully examined and an alternative toxicity assessment method to overcome these limitations was proposed, where the artifacts caused by extracellularly formed formazan and light scattered by agglomerated NPs were minimized by measuring only the intracellular formazan via image cytometric methods.

• 대한임베디드공학회논문지
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• 제11권4호
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• pp.209-218
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• 2016

This paper proposes a new lifetime aware buffer mapping method of a synchronous dataflow (SDF) graph on a hybrid memory system with DRAM and PRAM. Since the number of write operations on PRAM is limited, the number of written samples on PRAM is minimized to maximize the lifetime of PRAM. We improve the utilization of DRAM by mapping more buffers on DRAM through buffer sharing. The problem is formulated formally and solved by an optimal approach of an answer set programming. In experiment, the buffer mapping method with buffer sharing improves the PRAM lifetime by 63%.

• 유공압시스템학회논문집
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• 제5권1호
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• pp.13-19
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• 2008

The typical hydraulic system of hoist is composed of a hydraulic supply unit, a directional control valve, counter balance valve, and flow control valves. The flow capacity coefficients of flow control valves should be adjusted so that the hoist is operated at moderate speed and the hydraulic energy loss is minimized. However, it is difficult to adjust the flow coefficients of flow control valves by trial and error for optimal operation. Here, the steady state model of the hoist hydraulic system including the differential cylinder circuit is derived and the optimal flow capacity coefficients of flow control valves are obtained using the complex method that is one kind of constrained direct search method.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2002년도 추계학술대회 논문집
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• pp.42-45
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• 2002

In this paper, multiphase optimization of machine Tool structure is presented. The final goal is to obtain 1) light weight, 2) statically and dynamically rigid. and 3) thermally stable structure. The entire optimization process is carried out in three phases. In the first phase, multiple static optimization problem with two objective functions is treated using Pareto genetic algorithm. where two objective functions are weight of the structure and static compliance. In the second phase, maximum receptance is minimized using simple genetic algorithm. And the last phase, thermal deflection to moving heat sources is analyzed using Predictor-Corrector Method. The method is applied to a high speed line center design which takes the shape of back-column structure.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2014년도 추계학술대회 논문집
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• pp.771-772
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• 2014

In this paper, the integrated design method of suction muffler in compressor was studied. There are three things to consider when designing this. First, the transmission loss was maximized to consider the noise reduction. Second, dissipation energy of fluid flow was minimized for energy efficiency. Finally, acoustical resonance frequency of suction muffler was controlled because energy efficiency can be increased by supercharging of refrigerant. Therefore, suction muffler was designed to have the specific resonance frequency. The input impedance was used for designing target acoustical resonance frequency. Topology optimization was used for optimization method.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 하계학술대회 논문집 A
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• pp.3-5
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• 2001

When a fault occurs on distribution network. blackout region may happen, then it should be restored as fast as possible to minimize interruption of electric service. In this paper. A near optimal method to restore distribution network is proposed. For an optimal restoration, the number or switching operations must be minimized. The proposed method generates a general restoration plan for any distribution network fault and designed to reduce switching operations considering available load transfers. In this method overall process time can reduce with heuristic rules, which make a reduction of search space before restoration process. To achieve a near optimal solution, multiple load transfer algorithm is proposed too.