• 한국에너지공학회:학술대회논문집
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• 한국에너지공학회 2004년도 추계 학술발표회 논문집
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• pp.95-100
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• 2004

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2010년도 춘계학술대회 논문집
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• pp.855-856
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• 2010

• 대한수학회논문집
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• 제16권4호
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• pp.667-677
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• 2001

We consider a nonsmooth multiobjective opimization problem(PE) involving locally Lipschitz functions and define gen-eralized invexity for locally Lipschitz functions. Using Fritz John type optimality conditions, we establish Fritz John type sufficient optimality theorems for (PE) under generalized invexity.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2002년도 추계학술대회논문집
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• pp.128-133
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• 2002

The main obstacle to high track density in HDD is the structural resonances of the suspension. The most critical mode is sway mode and second torsion mode, when a data is read and written. It is common fact that the effect of two modes is smaller when a thickness is bulky. But the stiffness of suspension is smaller, the slider can follow a disk better. Because these two fact are reciprocal, a compromise is needed. So we investigated another method to improve band width without changing of the thickness of suspension but with changing of the shape. In this paper, we use two method - Sensitivity analysis and SIP using ADS. And we obtained the optimized value close to target value.

• 대한기계학회논문집A
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• 제24권5호
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• pp.1246-1253
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• 2000

Wire ropes are widely used in cable car, suspension bridge and elevator, etc. and there has been a growing need for ropes of large diameter. The theoretical procedures to obtain the stiffness coefficients of wire ropes, using previously reported theory, are programmed and the verification of the program is made. The effects of lay angle on the stiffness of strand are researched and comparisons on stiffness of rope are made according to the lay type. Axial stiffness optimization problems with coupling and torsional stiffness constraints are formulated and the effects of constraints on other stiffness coefficients on axial stiffness optimization are investigated.

• International Journal of Safety
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• 제9권2호
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• pp.6-10
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• 2010

The flash point of liquid solution is one of the most important flammability properties that used in hazard and risk assessments. Minimum flash point behaviour (MFPB) is showed when the flash point of a liquid mixture is below the flash points of the individual components. In this paper, the lower flash points for the flammable binary system, n-decane+n-octanol, were measured by Pensky-Martens closed cup tester. This binary mixture exhibited MFPB. The measured flash points were compared with the values calculated by the Raoult's law and the optimization method using van Laar and UNIQUAC equations. The optimization method were found to be better than those based on the Raoult's law, and successfully estimated MFPB. The opimization method based on the van Laar equation described the experimentally-derived data more effectively than was the case when the prediction model was based upon the UNIQUAC.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2001년도 추계학술대회논문집 II
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• pp.1266-1272
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• 2001

This paper discusses the multi-level optimization method in dynamic optimization problems, through stiffened plate of ship structures. In structural optimization, the computational cost increases rapidly as the number of design variables increases. And we need a great amount of calculation and time on problems of modified dynamic characteristics of large and complicated structures. In this paper, the multi-level optimization is proposed, which decreases computational time and cost. The dynamic optimum designs of stiffened plate that control the natural frequency and minimize weight subjected to constraints condition are derived. It is shown that the results are effective in the optimum modification for dynamic characteristics of the stiffened plate.

• 한국항행학회논문지
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• 제13권5호
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• pp.736-741
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• 2009

본 논문은 분할된 선형배열안테나를 사용하는 다중 사용자 MIMO 기술에서 코드북(codebook)을 운용 환경에 따라 최적화 하는 기술을 제안한다. 제안하는 기술은 공간상관도가 없는 MIMO 채널을 가정하여 디자인된 코드북을 각 순방향 링크의 송신 공간상관행렬을 이용하여 컬러링(coloring)하는 기술이며, 이를 위해 필요한 각 링크의 송신 상관행렬을 제한된 양의 long-term 피드백을 통해 피드백하는 기술을 제안한다. Zero-forcing maximum eigenmode transmission 기술을 사용하는 다중 사용자 MIMO 시스템에서, 제안하는 코드북 최적화 기술의 성능을 분석하였으며, 제안하는 기술이 적은양의 추가 피드백 정보량으로 다양한 운용 환경에 적응적으로 코드북을 최적화함을 보인다.

• 멤브레인
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• 제9권4호
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• pp.193-201
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• 1999

기존의 정수처리 공정인 응집 침전 과정을 대체하여 분리막을 이용한 상수처리 시스템의 개발을 목적으로한다. 따라서 4가지 형태의 정수처리 공정과 분리막의 분획 분자량을 변화시켰을 때 막 투과수의 변화와 안정적이며 높은 투과수를 얻기 위해 필요한 운전 조건의 최적화를 실험하였다 실험결과 한외여과막이 정밀여과막보다 막 투과수 감소경향이 완만했으며 초기 투과수 회복율은 더 높았다. 수질 분석의 결과 한회여과막이 정밀 여과막보다 우수하였지만 전처리에 의한 차이는 나지 않았다. 운전 조건에 따른 flux 는 온도, 선속도가 높을수록 압력이 낮을수록 flux 감소율이 적은 경향을 나타내었다.

• 제어로봇시스템학회논문지
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• 제17권10호
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• pp.1029-1036
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• 2011

An energy-efficient reference walking trajectory generation algorithm is suggested utilizing allowable ZMP (Zero-Moment-Point) region, which maxmizes the energy efficiency for cyclic gaits, based on three-dimensional LIPM (Linear Inverted Pendulum Model) for biped robots. As observed in natural human walking, variable ZMP manipulation is suggested, in which ZMP moves within the allowable region to reduce the joint stress (i.e., rapid acceleration and deceleration of body), and hence to reduce the consumed energy. In addition, opimization of footstep planning is conducted to decide the optimal step-length and body height for a given forward mean velocity to minimize a suitable energy performance - amount of energy required to carry a unit weight a unit distance. In this planning, in order to ensure physically realizable walking trajectory, we also considered geometrical constraints, ZMP stability condition, friction constraint, and yawing moment constraint. Simulations are performed with a 12-DOF 3D biped robot model to verify the effectiveness of the proposed method.