• Nuclear industry
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• v.19 no.7 s.197
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• pp.31-34
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• 1999

99년 6월 21일 오전 11시. 울진 3호기의 모든 전산 설비의 날짜 및 시간이 2000년 00시 00분으로 변경되어 발전소의 모든 설비들은 2000년과 똑같은 상황하에서 운전되고 있었고 원자로 출력, 발전기 출력도 정상 상태를 유지하고 있었다. Y2K 종합 실증 실험은 50여분 동안 진행되었으며, 2000년 연도 전환 시험, 날짜 지정 시험, 윤년 인식 시험, 그리고 마지막으로 안전 설비 동작 시험순으로 시험이 진행되는 동안 아무런 설비의 이상 징후나 이상 상태 발생 없이 성공적으로 시험이 완료되었다. 지난 일년여 동안 Y2K 문제 해결을 위해 노력해온 모든 직원들의 노고가 한순간에 보상받는 순간이기도 했다. Y2K 종합 실증 실험이 끝나고 난후에 주제어실과 현장의 주요 설비들이 전보다 더 신뢰가 가고 튼튼해 보였던 것은 나만의 느낌이 아니었으리라 생각한다. 그 동안 수고한 모든 이들의 정성이 범국가적 아니 범세계적 핫이슈인 Y2K 문제를 원전의 울타리 밖으로 멀리 쫓아 버렸으며, 청정 에너지원인 원자력을 국민들로부터 더욱더 사랑받을 수 있도록 하는 계기가 되었다고 자평하고 싶다. 그 동안 울진 3호기 Y2K 종합 실증 시험을 마치기까지의 추진 경위와 Y2K 실증 시험 결과, 그리고 향후 대책 등에 대해서 간단히 소개하고자 한다.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.30 no.2
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• pp.12-20
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• 2002

Three dimentional unsteady Euler equations are solved and an integration method is presented to predict the dynamic stability derivatives of transonic missiles. Results for the Basic Finner model are compared with several experimental data to vaildate the prediction capability of the present method. The variations of dynamic stability derivatives are discussed with respect to angle of attack, Mach number, and rotation rate. Results show that shock waves between fins enhance the pitch-damping characteristics in transonic region. Results also imply that the Euler equations can give the damping coefficients with comparable accuracy.

• Proceedings of the Membrane Society of Korea Conference
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• 1997.10a
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• pp.33-36
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• 1997

1. 서론 : 압력-구동 막공정을 분리공정에 응용시 커다란 장해는 막표변과 내부에 용존 및 부유물질들의 성장과 침착현상이다. 지난 수년 동안에 여러 연구자들이 유체의 불안정성을 이용하여 농도분극과 오염현상을 효과적으로 제거할 수 있음을 보였다.(생략)

• 전기의세계
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• v.26 no.2
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• pp.30-34
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• 1977

1977년 2월 1일 당연구소는 시내수표동에 있는 전기회관에서 상공부장관과 내빈다수를 모시고 현판식을 가졌다. 그동안 중전기시험소설립추진위원회는 1년간 계획과 검토를 거쳐 전기업계의 숙원이던 본 연구소가 대통령각하를 설립자로 모시고 관민공동출원으로 재단법인으로 설립등기를 마치고 업무를 개시하여 1980년 정상가동을 목표로 업무를 착수하였다. 본고에서는 설립경위와, 사업계획에 관해 알아보고자 한다.

• Aerospace Engineering and Technology
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• v.2 no.2
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• pp.1-10
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• 2003

An airship is statically unstable, because it has no wing, comparatively small tail and large hull. Hence, an accurate prediction of dynamic stability is critical. In this study, dynamic stability data of the Mid-Size Airship is acquired through forced oscillation wind tests. The test was done in BAR LAMP which is Birhle Applied Research Inc's facility located in Germany. The test was composed with 16 static runs and 26 dynamic runs. As a result, dynamic characteristics of the airship depends on sideslip angle, angular rate and its direction as well as angle of attack. Generally, it is obtained that 3 directional moments have damping, but normal force, side force, and cross-derivatives are unstable. The dynamic derivatives are not sensitive to control surfaces, but have nonlinear dependency on sideslip angle.

• Journal of the Society of Naval Architects of Korea
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• v.36 no.3
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• pp.60-70
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• 1999

The longitudinal stability characteristics of a Wing-In-Ground Effect Craft are quite different from that of the conventional airplane due to the existence of force and moment derivatives with regard to height. This stability characteristics plays a great role in designing a safe and efficient WIG due to its potential danger in sea surface proximity. The static and dynamic stability criteria are derived from the motion equations of WIG in the framework of small disturbance theory and discussed in the paper. The static and dynamic stability analyses of a 20-passenger WIG are conducted based on the wind tunnel test data and the dynamic motion behaviors are investigated for the change of the design parameters. Finally, the flying quality of the 20-passenger WIG is analysed at the cruising condition according to the military regulations.

• Journal of the Korea Institute of Military Science and Technology
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• v.2 no.2
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• pp.61-69
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• 1999

A dynamic stability test was performed to determine dynamic stability derivatives for the pure pitching motion of air-to-ground missile model in the low speed wind tunnel. The free vibration technique was employed to acquire oscillation characteristics of the model for damping coefficients. Damping coefficients are obtained by the method of logarithmic decrement. Results show good damping effects and stability capability at Mach numbers 0.1 and 0.2, with the angle of attack ranging from -15 to +20 degrees.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.34 no.6
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• pp.83-91
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• 2006

An advanced method of Relaxed Static Stability (RSS) is utilized for improving the aerodynamic performance of modern version supersonic jet fighter aircraft. The flight control system utilizes RSS criteria in longitudinal axis to achieve performance enhancements and improve stability. The flight control law of T-50 advanced trainer employs RSS concept in order to improve the aerodynamic performance and guarantee aircraft stability. The longitudinal center of gravity(X-c.g) varies as a function of external stores, fuel state and gear position. Shifts in X-c.g relate directly to longitudinal static margin in aircraft stability. This paper deals the maximum aft X-c.g for critical aircraft loadings and checks static margin limits using sensitivity such as damping, natural frequency, gain and phase margin. And nonlinear analysis was conducted for such as short period input. And also, this paper shows the T-50 aircraft stability based on the result of high angle of attack flight such as upright and inverted departure.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.40 no.10
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• pp.888-893
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• 2012

This paper described the wind tunnel testing apparatus and technique to acquire the dynamic stability derivatives of large slenderness ratio air vehicle such as the guided missiles or rockets. There have been few difficulties in conducting wind tunnel testing for slender long rocket due to the size limitation of the test section size and the installation of oscillation equipments. In this study, the dynamic stability balance was used as the wind tunnel technique for obtaining the dynamic stability derivatives. Through the wind tunnel testing, the experimental apparatus for slender air vehicle's oscillation is established. The measured data showed that it is possible to acquire the dynamic stability derivatives of large slenderness ratio rocket, properly.

• KIPS Transactions on Software and Data Engineering
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• v.5 no.5
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• pp.231-242
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• 2016

In order to meet rapid changes of Web information, it is necessary to extend the current Web technologies to represent both the valid time and location of each fact and knowledge, and reason their relationships. Until recently, many researches on qualitative temporal reasoning have been conducted in laboratory-scale, dealing with small knowledge bases. However, in this paper, we propose the design and implementation of a parallel qualitative temporal reasoner, MRQUTER, which can make reasoning over Web-scale large knowledge bases. This parallel temporal reasoner was built on a Hadoop cluster system using the MapReduce parallel programming framework. It decomposes the entire qualitative temporal reasoning process into several MapReduce jobs such as the encoding and decoding job, the inverse and equal reasoning job, the transitive reasoning job, the refining job, and applies some optimization techniques into each component reasoning job implemented with a pair of Map and Reduce functions. Through experiments using large benchmarking temporal knowledge bases, MRQUTER shows high reasoning performance and scalability.