• 한국재료학회:학술대회논문집
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• 한국재료학회 2002년도 추계학술발표강연 및 논문개요집
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• pp.124-124
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• 2002

• 디지털산업정보학회논문지
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• 제8권2호
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• pp.199-211
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• 2012

There have been studies to evaluate valuation of firms by using patents in various ways. Also, the theory that value of patents helps enterprise's growth is valid in economics. However, when evaluating the value of the company, through the patent evaluation has not been used. Because of previous studies researched relation between patents and firms only at certain points. To solve this problem, this study intends to analyze lag between patent and profitability of the firms. In this study, we classified top 100 software firms in the United States through PBR, PER and value of intangible assets by using cluster analysis. And we applied Almon's distributed lag model to each cluster to find out lag between patent and profitability of the firms. As a result, in the cluster of more valuable companies, patents have an effect on profitability of the firms at regular lags. This study indicates that the patents are an important indicator to assess companies.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2005년도 International Meeting on Information Displayvol.I
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• pp.513-514
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• 2005

In plasma processing reactors, it is common practice to control plasma density and ion bombardment energy by manipulating excitation voltage and frequency. In this paper, a dually excited capacitively coupled rf plasma reactor is self-consistently simulated with a three moment model. Effects of phase differences between primary and secondary voltage waves, simultaneously modulated at various combination of commensurate frequencies, on plasma properties are investigated. The simulation results show that plasma potential and density as well as primary self-dc bias are nearly unaffected by the phase lag between the primary and the secondary voltage waves. The results also show that, with the secondary frequency substantially lower than the primary frequency, secondary self-dc bias remains constant regardless of the phase lag. As the secondary frequency approaches to the primary frequency, however, the secondary self-dc bias becomes greatly altered by the phase lag, and so does the ion bombardment energy at the secondary electrode. These results demonstrate that ion bombardment energy can be more carefully controlled through plasma simulation.

• 디지털융복합연구
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• 제10권8호
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• pp.341-346
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• 2012

본 연구에서는 이러닝 환경에서의 학습참여도에 플로우 경험과 인터넷 중독이 미치는 영향을 고찰하였다. 학습참여도는 이러닝 웹 로그 분석을 통해 학습컨텐츠 접속횟수, 접속시간 및 지연시간(컨텐츠 업로드 시간과 접속시간의 시차)을 산정하여 활용하였으며, 이러한 학습참여 변인과 학업성취도간의 관계 또한 분석되었다. 연구결과, 플로우 경험은 모든 이러닝 참여 관련변인과 유의한 관계가 있는 것으로 나타났으며, 인터넷 중독은 지연시간과 유의한 관계가 있는 것으로 파악되었다. 그리고 여학생은 남학생에 비해 더 자주, 더 오래 학습컨텐츠에 접속한 것으로 나타났다. 이러닝 참여 변인 중에서는 접속횟수와 지연시간이 학업성취도에 유의한 영향을 미치는 것으로 파악되었다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1988년도 추계학술대회 논문집 학회본부
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• pp.426-429
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• 1988

A Microprocessor Based Digital Control System is inherently contained a control lag for processing the control program and a data detection time lag. This two types of time lag may cause the system to become unstable. In this paper proposed predictive state observer is used to solve the two time lag problems. I-P control algorithm is used to attain deadbeat response by adjusting the observer gain to overcome the parameter variation or with disturbance. The speed response shows good performance through computer simulation.

• 한국군사과학기술학회지
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• 제3권2호
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• pp.121-130
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• 2000

A practical method is proposed to improve hit probability of the digital gun fire control system, when the measured rate of the tracking sensor becomes biased under some operational situation. For ground moving target it is shown that the well-known Kalman filter which uses position measurement only can be optimally used to eliminate the rate bias error. On the other hand, for 3D moving aircraft we present a new algorithm which incorporate FIR-type filter, which uses position and rate measurement at the same time, and the fixed-lag smoother using position measurement only, and show that it has the optimal performance in terms of both estimation accuracy and response time.

• 전기학회논문지
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• 제62권6호
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• pp.756-761
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• 2013

This paper propose the new demodulation method that can detect resolver signal's peak at the time of position estimation when the position information is required during current controller period. The proposed method is performed in a synchronous demodulation way with exciting signal and also cover a capability which can compensate the lag element of exciting signal caused by the resolver's inductive component and filter circuit. This paper carried out the experiment to investigate the validity and performance of the suggested method by using the test board made up of DSP and demodulation circuit. The test results show that the proposed method is theoretically clear and work completely as expected from making sure of sampling resolver signal's peak at the time of position estimation. In addition, Software position tracking algorithm is executed with the demodulated signals generated by the suggested method and an exact position can be estimated.

• 한국정밀공학회지
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• 제14권4호
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• pp.88-96
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• 1997

This paper suggests a new non-linear friction compensation for digital control systems. This control adopts a hysteresis nonlinear element which can introduce the phase lead of the control system to compensate the phase delay comes from the inherent time delay of a digital control. A proper Lyapunov function is selected and the Lyapunov direct method is used to prove the asymptotic stability of the suggested control.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1996년도 추계학술대회 논문집
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• pp.987-993
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• 1996

This report suggests a new non-linear friction compensation for digital control systems. This control adopts a hysteric nonlinear clement which can introduce the phase lead of the control system to compensate the phase delay comes from the inherent time delay of a digital control. The Lyapunov direct method is used to prove the asymtotic stability of the suggested control, and the stability and the effectiveness are verified analytically and experimentally on a single axis servo driving system.

• 디지털산업정보학회논문지
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• 제6권2호
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• pp.129-141
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• 2010

In network service environment, cultures from diversified fields are easily accessible thanks to the convenient digital content services. Unfortunately, unauthorized access and indiscreet misuse behaviors have deprived content owners of their copyrights. This study suggests an integrity-ensured model applicable for forensic evidence of digital content infringement in network service environment. The suggested model is based on MPEG-21 core components for digital content protection and the system is designed in connection with the components of digital content forensics. Also, the present study suggests an efficient technology to protect and manage computer forensic evidence and digital content by authorizing digital content use and catching infringing logs of authorized users without lag in network environment for the benefit of network security and reliability.