• Transactions of the Korean Society of Mechanical Engineers
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• v.13 no.6
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• pp.1183-1192
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• 1989

본 논문에서는 평면변형률 상태하에서 안정하게 성장하는 균열선단에 집중 되어있는 강소성역의 해석에 역점을 두어 재결정법과 탄.소성유한요소법을 도입하여 안정 성장균열 선단에 형성되는 균열 성장저항에 직접적인 영향을 미치고 있는 소성 역의 크기나 형태에 대한 실험 및 해석을 하였다.

• Journal of Institute of Control, Robotics and Systems
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• v.4 no.5
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• pp.567-573
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• 1998

본 논문에서는 입력과 상태변수에 hard constraint가 있는 이산시간 시스템에 대한 새로운 이동구간 제어기를 제안한다. 제안된 이동구간제어기가 terminal ellipsoid constraint를 이용하여 지수 안정성(exponential stability)을 보장함을 보인다. Feasibility를 증가시키기 위하여 시스템을 안정 모드와 불안정 모드로 바꾸는 방법, constraint를 완화하는 방법을 제안한다. Constraint를 완화할 때 constraint를 만족시키지 못하는 부분의 성능을 개선시키는 방법을 제안하고 예제를 통해서 몇 가지 제안한 방법들을 비교한다.

• The Journal of the Korea Contents Association
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• v.14 no.11
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• pp.858-863
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• 2014

Through this study, we found out whether to measure objectively by using Transactional Analysis(TA) evaluating their own growth and benefit of health through the change of Ego-state, the personality structure and brain waves monitoring electric signals occurring in the brain of the human biological signals. According to the results of brain-wave test, M-type is brain-waves of healthy adults and a, ${\beta}$ were dominantly observed in the occipital while not sleeping. In particular, ${\beta}$ appears widely throughout the brain during nervous or concentrating metal activities and unlike N-type experimenters, ${\beta}$ was found to be dominant in M-type experimenters even in stable condition. N-type is brain waves of healthy adults and a, ${\beta}$ were dominantly observed in the occipital while not sleeping. In particular, unlike nervous or concentrating M-type, there was no noise such as tension and blink while resting. In addition, it turned out that subjects with high levels of A ego do not return quickly to the stable state and show a lot of Blinking and swallowing saliva, noise regardless of the pattern of Egogram. And brain waves of 11 people that the difference in data of OK-gram and Ego-state is the same in all items or less than -5 showed a low amplitude of $20{\mu}V$ in general. In conclusion, this study identified that the theory of personality pattern of Transactional Analysis Theory and brain-wave findings are consistent and also found out that brain waves are also associated according to each Ego-state of Egogram.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.37 no.7
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• pp.36-42
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• 2000

Some polarization characteristics of reflection type photopolymer are investigated. Photopolymer on a Mylar substrate alters an incoming linearly polarized laser beam to an elliptical polarization. Due to the rotation of the polarization, the recording gratings show different diffraction efficiencies. The rotation angle is of order of 10-50% for the tested samples. It is found that the polymer layer does not changes the polarization direction but the Mylar substrate alone distorts the incoming polarization to a comparable degree. As align the polarization states of photopolymers to be parallel with a laser using a He-Ne laser(633nm), which is not sensitive to that material, it was possible to make high diffraction efficiency gratings.

• Journal of the Institute of Electronics and Information Engineers
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• v.52 no.8
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• pp.140-147
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• 2015

In this paper, we propose a state feedback robust controller of 2-axis gimbal system which have bounded parametric uncertainty. The proposed controller is robust against dynamics variations of gimbal system and contains a dynamic compensator in order to improve a steady state error and a transient response. The stability of the closed-loop system is proved by Lyapunov approach. The performance of the proposed method is demonstrated by simulation on a 2-axis gimbal system.

• Proceedings of the KIEE Conference
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• 2001.07d
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• pp.2228-2230
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• 2001

TCP/IP 프로토콜을 사용하여 서버와 클라이언트를 연결하고 서버는 무선랜을 이용하여 여러 개의 디바이스를 제어할 수 있는 분산제어시스템을 구현했다. 디바이스의 제어 명령과 모니터링을 하는 클라이언트는 LAN을 통하여 서버에 접속한 후 디바이스 제어 명령을 서버에 전달한다. 서버는 디바이스 제어 명령을 수신한 후 실제 데이터만을 골라내어 디바이스가 받아들일 수 있는 데이터 형식으로 변환하여 RF 모듈을 통해 디바이스에 전달한다. 서버로부터 데이터를 수신한 디바이스는 제어명령을 실행한 후 센서는 디바이스의 상태를 체크하여 RF모듈을 통하여 서버에 전달한다. 다시 서버는 디바이스의 상태를 클라이언트가 받아들일 수 있는 데이터형식으로 변환하여 전달하고 클라이언트는 서버로부터 데이터를 수신하여 디바이스의 상태를 모니터링 한다. 각각의 디바이스는 자신만의 마이크로 프로세서를 가짐으로서 서버로부터 간단한 명령을 받아 각 프로세서가 스스로 판단하고 동작을 하게 된다. 서버와의 연결이 끊어질 경우 마이크로프로세서에 마지막 들어온 제어명령의 상태를 유지한다. 이 논문은 인터넷을 이용한 무선장치의 제어할 수 있는 안정된 시스템의 구현방법을 제시하며 서로 다른 프로토콜을 연결시키기 위하여 데이터의 구조를 변환시키고 여러 개의 디바이스가 안정된 동작을 도록 하는 방법을 제안했다.

• Journal of KIISE:Information Networking
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• v.29 no.2
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• pp.174-180
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• 2002

With the invention of MPLS and the Improvement in traffic engineering, multipath packet forwarding and dynamic load control has become a reality. A dynamic load control, while it can improve network efficiency by controlling loads between paths according to the network state, can lead to unstable and oscillating state because of the staleness of the state information. In this paper, we propose a efficient load control scheme which remains stable. The proposed scheme introduces prediction to reduce the staleness of state message and to prevent oscillation.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.5 no.5
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• pp.413-420
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• 2004

In this paper, the control algorithm of DC source device for inverter starting is proposed and the control method for compensating unbalance system source on operating time in the voltage type PWM converter with driving and regenerative faculty is suggested. The maintaining method of balancing condition for converter of AC source is used the compensating unbalanced status by current control loop. In order to solve the problem which the unbalanced system control is used to leakage transformer not equaled reactance by each phase in rectifier system. The proposed H/W and control algorithm of rectifier system is contributed to minimize of device and rising efficiency.

• Journal of the Korean Magnetics Society
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• v.27 no.2
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• pp.41-48
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• 2017

Recent study shows that ordered alloy of $L1_2$ $XPt_3$ (M = V, Cr, Mn, Co, and Fe) exhibits various magnetic phases such as ferromagnetic-to-antiferromagnetic transition at the $MnPt_3$ surface. Moreover, it has been argued that $CrPt_3$, in particular, possess large magnetocrystalline anisotropy and Kerr rotation with possible violation of Hund's rule. As such, we extend our work to thickness dependence of the magnetic structure of $CrPt_3$ thin film using density functional theory. Magnetic ground state of the bulk $CrPt_3$ turns out to be ferromagnetic (FM), where other magnetic phases such as A-type (A-AF), C-type (C-AF), and G-type antiferromagnetic (G-AF) state have higher total energies than FM by 0.517, 0.591, and 0.183 eV, respectively, and magnetic moments of Cr in bulk are respectively 2.807 (FM), 2.805 (A-AF), 2.794 (C-AF) and $2.869_{{\mu}_B}$ (G-AF). We extend our study to $CrPt_3$(001) thin films with CrPt-and Pt-termination. The thickness and surface-termination dependences of magnetism are investigated for 3-9 monolayers (ML), where different magnetic phases from bulk emerge: C-AF for CrPt-terminated 3 ML and G-AF for Pt-terminated 5 ML have energy difference relative to FM by 8 and 54 meV, respectively. Furthermore, thickness- and surface-termination-dependent magnetocrystalline anisotropies of the $CrPt_3$(001) films are discussed.

• Journal of Advanced Navigation Technology
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• v.21 no.6
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• pp.608-613
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• 2017

In this paper, we consider the stability bound for uncertainty of delayed state variables in the linear discrete interval time-varying systems with time-varying delay time. The considered system has an interval time-varying system matrix for non-delayed states and is perturbed by the unstructured time-varying uncertainty in delayed states with time-varying delay time within fixed interval. Compared to the previous results which are derived for time-invariant cases and can not be extended to time-varying cases, the new stability bound in this paper is applicable to time-varying systems in which every factors are considered as time-varying variables. The proposed result has no limitation in applicable systems and is very powerful in the aspects of feasibility compared to the previous. Furthermore. the new bound needs no complex numerical algorithms such as LMI(Linear Matrix Inequality) equation or upper solution bound of Lyapunov equation. By numerical examples, it is shown that the proposed bound is able to include the many existing results in the previous literatures and has better performances in the aspects of expandability and effectiveness.