• 한국통신학회논문지
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• 제24권6A호
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• pp.894-904
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• 1999

본 논문에서는 실제 채널 환경에 효율적인 암호 통신을 제공하는 동기식 스트림 암호 통신 체계를 설계하였으며, 그 암호 시스템의 비도를 분석하였다. 제안된 시스템의 주요 구성 부분은 동기 패턴, 세션 키, 키 수열 발생기이며, 이에 대한 시스템 성능을 랜덤성, 주기, 선형 복잡도, 상관 면역도에 따라 비도 분석하여 무선 채널에 적합함을 판정하였다. 시뮬레이션 결과는 10-1과 10-2채널 오류 환경에서 영상 신호를 이용하여 암복호의 타당성으로 나타내었다.

• 수산해양기술연구
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• 제28권1호
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• pp.27-38
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• 1992

The paper presents a digital speed control approach of induction motor systems by using a digital redesign method and adopting a well known 2nd order model as the system model equation. The basic concept using the modeling equation is induced from the control theory stand point such that we can describe usually the motor system connected by inverter, generator and load etc. just as a mechanical system to be controlled. The concept does not demand us the complicated vector-based modeling equation adopted in the traditional methods for the speed control of induction motor. The effectiveness of the servo control system composed by the above mentioned design concept is illustrated by the experimental results in the presence of step reference change and generator load variation. It is observed from the experimental results that the steady state error of the experimental set up becomes zero after some regulation time and the induction motor system is robust in spite of reference signal change and load variation of generator.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 추계학술대회 논문집 전력기술부문
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• pp.429-431
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• 2001

The vertically integrated power industry was divided into six generation companies and one market operator, where electricity trading was launched at power exchange. In this environment, the profits of each generation companies are guaranteed according to utilization of their own generation equipments. This paper represents on generator maintenance scheduling and efficient bidding strategies for generation equipments through the calculation of the contract and the application of each generator cost function based on the past demand forecasting error and market operating data.

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 1996년도 춘계학술발표회논문집(1)
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• pp.367-373
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• 1996

H$_{\infty}$ robust control theory is applied to the nuclear steam generator level control. Nuclear steam generator has the properties such as nonlinearity, non-minimum phase, and so, has some difficulties on level control. In a nuclear plant, it is more important to keep the operating variables under certain safety limits against various uncertainties than to meet the optimal performance. The designed H$_{\infty}$ controller shows robust level control against modelling error, disturbance in the nonlinear simulation. As the H$_{\infty}$ controller has both robustness and design transparency, it is adequate to the automation of level control and in licensibility

• International Journal of Contents
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• 제14권4호
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• pp.65-69
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• 2018

The objective of this study was to conduct a radiation shielding analysis for the facility equipped with radiation generator. The analysis was carried out in two aspects. First, from the aspect of the effect caused by primary and leakage radiation. Second, effect of scattered radiation was evaluated by applying a simple calculation method based on a scattering rate concept since effect of scattered radiation is significantly important at maze entrance of the radiation facility. The calculated results obtained using the simple method were compared to the results calculated using Geant4 code and the measured values. The results calculated by the suggested method indicate that slight error exists in a radiation shielding analysis done at the maze entrance comparing to other two results, while the results evaluated at the outside of the maze entrance door are relatively consistent with other values.

• Nuclear Engineering and Technology
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• 제55권10호
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• pp.3515-3524
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• 2023

A reinforcement learning framework is proposed for the control problem of outlet steam pressure of the once-through steam generator(OTSG) in this paper. The double-layer controller using Proximal Policy Optimization(PPO) algorithm is applied in the control structure of the OTSG. The PPO algorithm can train the neural networks continuously according to the process of interaction with the environment and then the trained controller can realize better control for the OTSG. Meanwhile, reinforcement learning has the characteristic of difficult application in real-world objects, this paper proposes an innovative pretraining method to solve this problem. The difficulty in the application of reinforcement learning lies in training. The optimal strategy of each step is summed up through trial and error, and the training cost is very high. In this paper, the LSTM model is adopted as the training environment for pretraining, which saves training time and improves efficiency. The experimental results show that this method can realize the self-adjustment of control parameters under various working conditions, and the control effect has the advantages of small overshoot, fast stabilization speed, and strong adaptive ability.

• 한국통신학회논문지
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• 제34권6C호
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• pp.619-625
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• 2009

이 논문은 ITU-T Recommendation J.83 Annex B에서 패킷 동기화와 에러 검출을 위해 사용된 패리티 체크섬 생성기의 병렬 구조를 제안한다. 제안된 병렬 처리 구조는 기존의 직렬 처리 구조에서 일어나는 병목현상을 제거하여 패리티 체크섬을 생성하는데 필요한 처리 시간을 상당히 줄여준다. 실험 결과는 제안된 병렬 처리 구조가 16%의 면적증가로 처리 속도를 83.1%나 줄일 수 있다는 것을 보여준다.

• 동력기계공학회지
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• 제16권1호
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• pp.19-23
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• 2012

This thesis is the result of conducting an analysis to find the solution to the phenomenon of power stoppage due to the disconnection of a CT (Current Transformer) because of vibration. The CT which measures the most essential current is used in power industries as part of a generator protection relay. When it comes to the bottom plate of a CT, nonconductor; such as bakelite and laminates; these material elements should be used because it is impossible to utilize the conductor when measuring the current of a generator which carries a high current if you use other materials. These nonconductor's material properties are irregular and interpretation errors often occur because the weight is light. In addition, since the change of dynamic characteristics which are related to the temperature often occur, it is important to match the real situation by considering an error of interpretation rather than selecting the quality of the material. Lastly, the conclusion that the study drew is that it is possible to avoid the resonance by utilizing three changes to the components to solve the problem concerning the high vibration which is caused by non-conductive objects. These changes are the most crucial points in this thesis: First, material changes to the Plate. Second, weight changes to the Coil. Third, thickness changes to the Plate.

• 한국정밀공학회지
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• 제24권5호
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• pp.56-61
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• 2007

In the braking of railway rolling stock, the slip that is the relative velocity between train body and its wheel affects the adhesive force which is connected to the braking force. The coefficient of the adhesive force changes in accordance with the slip and the condition of a rail road. Namely, its value increases upon the maximum on a rail condition, and there it declines conversely while the magnitude of slip keeps rising on. First, this paper introduced a reference slip generator so that can utilize maximum adhesive forces with a disturbance observer for estimating unmeasurable current adhesive forces which is as an input of the generator. And, an adaptive sliding-mode control system has been synthesized for minimizing the error between reference and current slip. Finally the effectiveness of the proposed control system is evaluated by computer simulation.

• 항공우주기술
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• 제9권1호
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• pp.93-97
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• 2010

액체산소/케로신을 사용하는 가스발생기 사이클 액체로켓엔진의 비추력 해석을 수행하였다. 본 해석 방법으로 재연한 300톤급 엔진의 시스템 성능은 문헌에 보고된 결과와 비교하여 비추력 0.1%, 최적 연소압 12%의 오차를 보였다. 오차의 주요 원인은 문헌에 공개되지 않은 서브시스템의 성능모델 차이와 가스발생기 생성물의 물성 모델 차이로 판단된다. 막냉각이 적용되는 30톤급 1단용 엔진의 경우, 연소압 68 bar에서 혼합비 2.2가 최적 비추력 조건인 것으로 평가되었으며 최적 조건은 주어진 성능 모델에 따라 달라질 수 있다.