• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 2005년도 춘계학술발표대회 개요집
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• pp.185-187
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• 2005

The reactor pressure vessel head of PWR has penetrations for control rod drive mechanism and instrumentation systems. The Primary coolant water and operating temperature can cause the stress-corrosion cracking of these nickel-based alloy penetrations. It is difficult to detect and size flaws such as SCC in the reactor head penetrations using conventional W methods because of complex geometry, Therefore, the utilities are using the TOFD technique for the detection and sizing of the flaw. This study shows the correlation between the ultrasonic wave direction and the orientation of the flaw and the range of flaw depth which can be detected by the TOFD techniques.

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 1997년도 추계학술발표회논문집(1)
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• pp.695-700
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• 1997

To enhance the safety of nuclear power plants, implementation of accident management has been suggested as one of most important programs. Specially, accident management strategies are suggested as one of key elements considered in development of the accident management program. In this study, generally applicable accident management strategies to domestic nuclear power plants are identified through reviewing several accident management programs for the other countries and considering domestic conditions. Identified strategies are as follows; 1) Injection into the Reactor Coolant System, 2) Depressurize the Reactor Coolant System, 3) Depressurize the Steam Generator, 4) Injection into the Steam Generator, 5) Injection into the Containment, 6) Spray into the Containment, 7) Control Hydrogen in the Containment. In addition, the systems and instrumentation necessary for the implementation of .each strategy are also investigated.

• 한국산학기술학회논문지
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• 제11권9호
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• pp.3417-3421
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• 2010

USN은 인간의 생활공간, 생활기기, 기계 등 모든 사물에 컴퓨팅 및 네트워킹 기능을 부여하여 환경과 상황의 자동인지를 통해 사용자에게 최적의 서비스를 가능하게 함으로써 인간생활의 편리성과 안정성을 고도화 하는 기술이라 할 수 있다. 본 논문에서는 이와 같은 USN기술을 이용하여 학습자의 학습환경을 실시간으로 파악하여 이를 기초로 최적의 학습환경으로 만들어주기 위한 학습지원시스템을 임베디드 시스템 기반으로 개발한다.

• International Journal of Contents
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• 제12권1호
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• pp.70-75
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• 2016

In this paper, we considered heterogeneous spectrum sharing system where the number of subcarriers of the primary user (PU) was twice as much as that of the secondary user (SU). In this case, due to non-orthogonality and inter-carrier interference (ICI) from SU to PU, it is difficult to satisfy the interference constraint of PU. In order to mitigate ICI and satisfy the interference constraint, we proposed a new transmission scheme of the SU with power allocation scheme. The proposed scheme will only generate subcarrier-by-subcarrier interference. Therefore, it can easily satisfy the interference constraint of the PR and enhance the capacity of the SU. In addition, we derived the ergodic capacity of the SU. Based on numerical results, we confirmed that the proposed schemes could guarantee SU with a reliable capacity while satisfying the interference constraint of the PU. In addition, the derived capacity well matched the numerical results.

• 센서학회지
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• 제5권4호
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• pp.47-56
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• 1996

속도제어루프내에서 외란의 각속도를 감지하여 짐발을 안정화시키기 위해 사용하는 동조자이로스코프에 대한 기본원리 및 특성을 분석하였다. 또한 비례모드 자이로스코프의 모델을 정확하게 제시하였으며, 제시된 모델은 공진 특성을 가지고 있기 때문에 기존에 사용하고 있는 2차 시스템 모델보다 실제 시스템의 특성과 유사하므로 일반적인 비례모드 자이로스코프에서도 적용 가능하다. 실제 시스템인 전자광학추적기에 사용할 경우 발생되는 문제점을 알아보고 그 해결 방안을 제시하였다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2000년도 제15차 학술회의논문집
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• pp.247-247
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• 2000

A new bioelectric impedance measurement method is proposed for the precise measurement of the bioelectric impedance. To obtain the impedance from the known applied a.c. current and the measured voltage signals, a frequency conversion circuit, like the mixer in heterodyne receivers, is introduced to reduce the frequency of the original current. It can be observed from several lines of derivation that the impedance is independent on the amplitude and phase of the mixing signals. This makes it possible to use low-speed analog-to-digital converters and thus utilize cheaper electronic parts in the implementation. The possibility of the method is shown by simulations, and a generic structure applicable to bioelectric impedance measurement devices is also proposed.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1996년도 하계학술대회 논문집 B
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• pp.1009-1011
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• 1996

This paper presents an approach to building multi-input and single-output fuzzy models for nonlinear data-based systems. Such a model is composed of fuzzy rules, and its output is inferred by simplified reasoning. Optimal structure and membership parameters for a fuzzy model are automatically and simultaneously identified by GA(Genetic Algorithm). Numerical examples are provided to evaluate the feasibility of the proposed approach. Comparison shows that the suggested approach can produce a fuzzy model with higher accuracy and a smaller number of fuzzy rules than the ones achieved previously in other methods.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1995년도 하계학술대회 논문집 B
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• pp.751-753
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• 1995

Practical controllers of industrial systems are usually designed and realized in continuous time domain. However, due to the programmable and flexible nature of digital computers and the speed and stability superioity of digital components over analog ones, it seems more effective to adapt digital controllers. When an existing analog controller performs satisfactory, it is often advantageous to use the digital redesign techinque to obtain an equlivalent digital controller which substitutes the analog one. One method of the digital redesign is to use a periodic gain. This method gives a riffle effect on the steady state response, although it's transient response is satisfactory. This paper suggests a method which eliminates or deminishes periodic ripples generated by the periodic function.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2001년도 ICCAS
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• pp.53.1-53
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• 2001

We have used many Instrumentations to acquire the performance data of vehicles for many years. but these could not satisfied with environment specifications (vibration, shock, temperature) and data processing speed to applicate the performance test for armored military vehicles because of having developed as a common vehicles/fixed installation equipments. So new rugged embedded measurement system required to do large data acquisition and high processing speed (Maximum sample rate : 1.25MHz/ch) with rugged environment specifications. We have developed embedded measurement system by using PXI(PCI eXtension for Instrumentation)bus interface which were composed of stand alone controller and versatile data acquisition boards(analog, digital, vision ...

• 전력전자학회논문지
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• 제23권6호
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• pp.381-388
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• 2018

A novel and simple algorithm for accurate calculation of RMS voltage is proposed in a digitally controlled grid-tie inverter system. Given that the actual frequency of grid voltage is continuously changing, the constant sampling frequency cannot be a multiple number of the fundamental frequency. Therefore, the RMS of grid voltage contains periodic oscillations due to the differences in the phase angle of sampled data during calculation. The proposed algorithm precisely calculates and updates the initial phase angle of the first sampled voltage in a half-cycle period using phase-locked loop, which is commonly utilized for phase angle detection in grid-tie inverter systems. The accuracy and dynamic performance of the proposed algorithm are compared with those of other algorithms through various simulations and experiments.