• 제어로봇시스템학회:학술대회논문집
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• 1997.10a
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• pp.692-695
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• 1997

Nonlinear robust attitude controller for 3-axis stabilized spacecraft is designed. Robust stability analysis for nonlinear spacecraft system with disturbance is conducted. External disturbances and parametric uncertainties decrease Spacecraft's attitude pointing accuracy. Sliding Mode Control(SMC) provides stability of system in the face of these disturbances and uncertainties. The concept of quadratic boundedness and quadratic stability are applied to the robust analysis for the nonlinear spacecraft system subject to bounded disturbance torques. Numerical simulation is conducted to compare the analysis result and actual nonlinear simulation. The simulation show that analysis result is valid.

• Proceedings of the IEEK Conference
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• 2000.06d
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• pp.155-158
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• 2000

In this paper, we propose a Windows-based presentation system using laser pointer mouse. Major-characteristics of this system is to synchronize the laser pointing position with the PC cursor such that the laser can function as not only pointer, but also a PC mouse. It is shown that we use a special pattern to coincide the coordinate of the camera capture image with that of the pc window. We finally show its feasibility by some experiments with the implemented system.

• The Journal of the Acoustical Society of Korea
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• v.15 no.2E
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• pp.8-13
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• 1996

The pseudomedian filter was designed to be a computationally effecient alternative to the median filter. However, a thorough analysis ofter pseudomedian filter reveals some important differences between its response and that of the median filter. This paper develops some formal properties of the pseudomedian filter. The root signal analysis demonstrates the close relatonship between the median and pseudomedian filters while pointing out important and useful differences.

• Journal of The Korean Astronomical Society
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• v.38 no.2
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• pp.223-226
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• 2005

We present the results of a 21cm radio continuum aperture synthesis mosaic of the Large Magellanic Cloud (LMC), made by combining data from 1344 separate pointing centers using the Australia Telescope Compact Array (ATCA) and the 64-m Parkes single-dish telescope. The resolution of the mosaicked images is 55' ( 10 pc, using a distance to the LMC) and a region $10^{\circ}{\times}12^{\circ}$ is surveyed.

• Proceedings of the Korean Geotechical Society Conference
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• 2000.03b
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• pp.387-394
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• 2000

In the present study, laboratory pull-out tests with screw anchors are carried out to investigate behavior characteristics of underground structures applied uplift seepage forces. Small scaled pull-out tests in sand were conducted under saturated condition. And then, it was observed that the upward displacement as well as the pullout load varied with spacing of the anchor. Also, analyses have been performed with the aim of pointing out the effects of various parameters on the group effect of the screw anchors.

• Proceedings of the ESK Conference
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• 1995.10a
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• pp.46-55
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• 1995

The multimedia documents becomes the most natural user interface for CSCW(Conputer Supported Cooperative Work) in distributed environment. The objective of this study is to propose a multimedia document architecture and to develop a system that can manage it well. The new architecture is for revisable documents and is the basic layer for hypermedia documents. A good document architecture for CSCW must support pointing, marking, and editing over a part of documents. The user views, version control, and full- content search are also desirable features. In this paper, we discuss the basic concept of a new document architecture for CSCW. We also present the user interfaces for spatio-temporal compositions of multimedia documents.

• Proceedings of the Korean Information Science Society Conference
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• 2003.04c
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• pp.564-566
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• 2003

재래의 TV의 경우 채널변경, 볼륨조절 등의 비교적 간단한 조작만이 필요했던 반면 앞으로 보편화될 인터랙티브 TV는 부가기능의 다양화로 좀더 복잡한 인터렉션을 요구한다. 인터렉티브 TV조작에 사용되는 기술은 트랙볼이나 조이스틱 같은 포인팅 디바이스를 리모콘에 부착하는 방법, 키보드를 이용한 입력, 팜탑 컴퓨터, 음성입력 등 다양한 방법이 있다. 본 논문에서는 초음파센서를 이용한 새로운 입력장치인 소나팬(SonarPen)에 대해 소개하고자 한다.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10b
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• pp.1103-1106
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• 1996

Disturbance Accommodating Attitude control logic for 3-axis stabilized spacecraft is designed and compared with PIID control logic. PID controller provide the zero steady error for constant disturbances. PIID controller detect and cancel disturbances upto the ramp input. PID control logic is designed as the main control logic. We designed the disturbance observer to detect the effect of disturbance using the sinusoidal function. The detected disturbance are compensated by the additional control logic. The comparison simulation is conducted between PIID and PIID with DAC. The simulation results show that PIID with DAC shows the better attitude pointing accuracy.

• The Bulletin of The Korean Astronomical Society
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• v.32 no.1
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• pp.42.2-42.2
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• 2007

• 한국정보디스플레이학회:학술대회논문집
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• 2006.08a
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• pp.571-576
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• 2006

We review work performed by our group and collaborators in the area of exciton formation. There are three components: (i) measurement of singlet fractions, (ii) analysis of magnetic resonance measurements, and (iii) models of exciton formation. We find that the fraction of singlet excitons is a controllable quantity, pointing the way to a new generation of all-fluorescent organic light emitting devices.