• 수산해양기술연구
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• 제28권2호
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• pp.208-215
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• 1992

Concept of primary solidification mode control was adopted to obtain optimal solidification crack resistance, hot ductility, corrosion resistance and toughness for austenitic stainless steel. By controlling primary solidification phase as primary $\delta$ and containing no ferrite at room temperature, optimal solidification crack resistance, hot ductility, corrosion resistance and cryogenic toughness could be obtained. The optimum chemical composition of austenitic stainless steel ranges 1.46~1.55(Creq/Nieq ratio) calculated by Schaeffler's equation.

• PNF and Movement
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• 제1권1호
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• pp.27-32
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• 2003

Objectives : The purpose of this study was conducted to find change and development of the proprioceptive neuromuscular facilitation(PNF). Methods: This is a literature study with books, seminar and book for the international courses. Results: Combination of isotonic has been started by Mr and Mrs Johnson after Miss Knott passed away. It is that the terms of maximum resistance changed into optimal or appropriate resistance. It is focus on activities. Maximum resistance focus not only activities but also irradiation have to fit with normal functions. PNF has enough for the motor control concepts and international classification of functioning(ICF)of WHO. Conclusions: PNF has changed and developed with giving resistance method. It is that changed from maximal resistance to optimal resistance. But it is smaller concept than maximum resistance. Even though PNF founded 60 years ago, it is enough for new concepts that is motor control and learning.

• Journal of Advanced Marine Engineering and Technology
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• 제26권1호
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• pp.59-67
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• 2002

The comparison of $J_{Rice}$-resistance considering a few strength ratio in Rice J-integral formula and $J_{\delta}$-resistance curves converted from experimental CTOD using appropriate strength chosen according to strain hardening level, n=10.6 (A533B steel) and n=8.1 (BS4360 steel) is carried out. The optimal dimensionless strength ratio like the factor of revision, (see full text)reflecting strain hardening level in Rice\`s experimental formula is found out and the reliability of appropriate reference strength chosen according to strain hardening level in different materials is investigated through doing that CTOD is transformed from $J_{\delta}$-integral using relationship between J-integral and CTOD. The results are as follows; 1) The optimal factor of revision is when m equals to 3 in (see full text) for Rice's and the above optimal factor of revision multiplies by coefficient, η in Rice's experimental formula instead of n=2, 2) and the pertinent reference strength for high strain hardening material like BS4360 steel is ultimate strength, $\sigma_{u}$ and for material like A533B steel is ultimate-flow strength, $\sigma_{u-f}$. The incompatible of the behavior of both experimental J-resistance curves using Rice's formula and CTOD-resistance curves for A533B and BS4360 steel by Gordon, et al., could be corrected using the optimal factor of revision in Rice\`s and the pertinent reference strength in J=$m_{j}$${\times}$$\sigma_{i}$${\times}$CTOD.

• Journal of Ship and Ocean Technology
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• 제9권3호
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• pp.1-13
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• 2005

A design procedure for a ship with minimum total resistance has been developed using a numerical optimization method called SQP (Sequential Quadratic Programming) to search for optimized hull form and CFD(Computational Fluid Dynamics) technique. The friction resistance is estimated using the ITTC 1957 model-ship correlation line formula and the wave making resistance is evaluated using a potential-flow panel method based on Rankine sources with nonlinear free surface boundary conditions. The geometry of hull surface is represented and modified using B-spline surface patches during the optimization process. Using the Series 60 hull ($C_B$ =0.60) as a base hull, the optimization procedure is applied to obtain an optimal hull that produces the minimum total resistance for the given constraints. To verify the validity of the result, the original model and the optimized model obtained by the optimization process have been built and tested in a towing tank. It is shown that the optimal hull obtained around $13\%$ reduction in the total resistance and around $40\%$ reduction in the residual resistance at a speed tested compared with that of the original one, demonstrating that the present optimization tool can be effectively used for efficient hull form designs.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1988년도 한국자동제어학술회의논문집(국내학술편); 한국전력공사연수원, 서울; 21-22 Oct. 1988
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• pp.370-373
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• 1988

Althouah there have been many attempts to control weld quality in resistance spot welding processes, design method for an on-line feedback controller based upon process dynamics has not been suggested. This is due to the fact that the resistance spot welding is a highly complicated process, whice involves the interaction of electrical, thermal, mechanical and metallurgical phenomena. In this paper, an optimal control method based on FDM model with shunt effect is presented, which can regulate the nugget size, at the same time minimizing the control heat input. Optimal PI gain of the controller were determined by numerical optimization. Simulation results show that, as a result of the proposed optimal control, the weld nugget can be made to approach a desired nugget size with less control heat input than that required for the conventional spot welding process in the face of the shunt effect.

• 한국항해항만학회지
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• 제48권4호
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• pp.249-260
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• 2024

본 논문에서는 컨테이너선의 조파 저항을 효율적으로 감소시킬 수 있는 기술과 관련하여 연구한 내용을 정리하였다. 컨테이너선에 적용이 가능한 조파저항 저감 기술을 개발하고 실선 설계에 사용하기 위하여 최적화 알고리즘, 선체 형상 변경 알고리즘, 선박 성능 예측 알고리즘, 자동화 알고리즘 그리고 반복적 최적 설계 기법을 적용하여 선형 최적 설계를 수행할 수 있는 컴퓨터 프로그램을 개발하였다. 선형최적 설계에 있어서 중요한 요소인 설계 변수의 적절한 설정과 설계 변수의 하한과 상한을 효율적인 설정을 위하여 민감도 분석 알고리즘을 개발하여 선형 최적 설계에 적용하였다. 개발된 컴퓨터 프로그램의 신뢰성과 실선 적용성을 예측하기 위하여 전 세계적으로 다양한 연구가 진행된 컨테이너선인 KCS(KRISO Container Ship) 선박에 대한 선형 최적 설계를 수행하였다. KCS 선박의 설계 속도인 Fn=0.26에서 선형 최적 설계를 수행하였으며, 대상 선박인 KCS 선박의 선형과 선형 최적 설계의 결과로써 도출된 선박의 선형에 대한 수치해석을 수행하여 조파 저항, 파형 그리고 파고를 구하고 서로 비교하였다. 결론적으로, 최적 선박은 대상 선박과 비교하여 조파 저항이 80.60% 감소하였고, 배수량과 침수 표면적은 각각 1.54%, 1.21% 감소하는 것을 알 수 있었다.

• 한국식물병리학회지
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• 제14권6호
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• pp.594-597
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• 1998

The optimal quantity of inoculum was determined to screen resistance of garlic cultivars against Sclerotium cepivorum and 30 cultivars was tested. The growth of the pathogen in detached roots, Disease incidence was increased when the inoculum density was raised form 10 to 100 sclerotia. The optimal inoculum density to differentiate resistance or susceptibility of garlic cultivars was seemed to be 50 sclerotia. The cultivars collected from England, Japan, Nepal and Turkey, and cultivars such as common red, PI1356104 and PI135693 were less than the other cultivars in their disease incidence. The growth of S. cepivorum in detached roots varied from 23 to 33 mm according to garlic cultivars. There was no relationship between the disease incidence and the growth in detached roots. The sclerotial germination was increased significantly when root extract was extract was added. The addition of only distilled water resulted in 13% germination, but the addition of 0.25 g of root extract in 100 ml distilled water resulted in more than 85% germination. There was no difference in the stimulation of sclerotial germination among cultivars which showed different resistance.

• 한국전기전자재료학회논문지
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• 제17권4호
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• pp.367-372
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• 2004

Two new extraction methods for the thermal Resistance of HBT(Heterojunction Bipolar Transistors) are proposed. First, the analytical expression, based on the thermal characteristics that the base to emitter junction voltage drops with the increase of junction temperature, is derived. Second, the thermal resistance equation that can predict the measured DC(Direct Current) data optimally is derived. These optimal thermal resistance expression is applied to the 2 finger 2${\times}$20${\mu}{\textrm}{m}$-AlGaAs/GaAs HBT and shows the good agreement with the measured data.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 추계학술대회 논문집 전력기술부문
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• pp.37-39
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• 2008

This paper suggests a decision scheme for optimal insertion resistance in an Superconducting Fault Current Limiter (SFCL) application to reduce the transformer inrush current. This scheme and the SFCL model are implemented using Electromagnetic Transient Program (EMTP). We determine the optimal SFCL resistance by EMTP simulation, and this value is applied to model the SFCL by EMTP. The simulation results show the validity and effectiveness of the suggested scheme and the ability of a SFCL to reduce the inrush current.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2014년도 춘계 학술논문 발표대회
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• pp.4-5
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• 2014

Planning earthmoving haul-route must be preceded for appropriate equipment fleet assignment. However, traditional haul-route planning methods have limitations relative to practical usage because multiple variables (e.g., grade/rolling resistance, length, equipment's weight etc.) should be considered at a time. Genetic algorithm(GA) was introduced to improve these traditional methods. However, GA based haul-route planning method still remains in inefficiency relative to computation performance. This study presents a new haul-route searching method that computes an optimal haul-route using GA. The system prototype is developed by using MATLAB(ver. 2008b). The system identifies an optimal haul-route by considering equipment type, soil type, and soil condition.