• Journal of the Korea Institute of Information and Communication Engineering
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• v.5 no.1
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• pp.118-124
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• 2001

In this paper, we proposed the novel digital watermarking for color still image using the characteristics of human visual system and the distribution of DCT coefficients. We insert watermark signal in the chromatic components of YCrCb color space according the characteristics of the human visual system that chromatic component are less sensitive than achromatic components. In order to extract the watermark signal, we use the relationship among the DCT coefficients of watermarked image without using original one. Simulation results show that the proposed watermarking method is better quality on invisibility than the conventional methods.

• Proceedings of the KIEE Conference
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• 2005.07d
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• pp.3069-3071
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• 2005

정밀 유도무기체계는 매우 큰 복잡도를 가지는 탄재 소프트웨어와 다양한 입출력을 가지는 하드웨어로 구성된다. 이에 대한 시험장비는 유도무기체계에 탑재되는 소프트웨어에 대한 검증 및 모든 입출력 신호를 수용할 수 있는 성능을 보유하여야 한다. 시험장비에 요구되는 일반적인 조건은 고속처리, 다양한 입출력 기능, 신호 변환 장치 등을 포함하고 Hard Real Time 실행성능을 만족하여야 하며, 각각의 하위 시스템을 통합 운영하기 위한 실시간 인프라 구조 소프트웨어가 구축되어야 한다. 본 논문에서는 실시간 운영체제를 탑재하고 다중 프로세서를 장착한 VME 기반의 임베디드 시스템 설계 방안 및 개발 장비에 관하여 기술하였다.

• Proceedings of the KIEE Conference
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• 1995.11a
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• pp.169-171
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• 1995

Automatic control equipment in hydro power plant, such as turbine governor or automatic voltage regulator have to act promptly against for variation of power system, so it is necessary to check and test continuously. During last five years, the performance test of automatic control equipment was performed about 20 units of hydro turbine generator. In this process, because it has complex connection and before calibration, signal conditioner was developed as an auxiliary equipment for performance test. It includes function of signal amplifier, transducer, and meters. As a result of use this equipment for electric governor test at soyang-gang hydro power plant, it was possible to find output data equal to old one.

• Proceedings of the Korean Society for Emotion and Sensibility Conference
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• 2000.11a
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• pp.127-130
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• 2000

HP를 비롯한 장치나 소프트웨어 관련 업체들은 인터넷에서 통용될 수 있도록 다양한 모니터들의 평균이 되는 sRGB 색공간을 제안하고 이를 기본 색공간으로 사용하고 있다. 본 연구에서는 sRGB 색공간과 XYZ 색공간 사이의 변환프로그램을 개발하여 웹 안전색으로 통용되고 있는 216가지의 디지털신호에 대해 sRGB 색공간에서 재현될 XYZ 색좌표를 예측해 보았다. 또한 실제로 두 대의 모니터에 216가지의 디지털 신호를 입력시켰을 때 재현된 색의 XYZ 색좌표를 측정하여 예측된 결과와의 차이를 비교함으로써 sRGB 색공간의 실효성을 분석하였다.

• Journal of Broadcast Engineering
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• v.8 no.4
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• pp.452-464
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• 2003

In this paper, a multi-view 3D video processor was designed and implemented with several FPGAs for real-time applications. The 3D video processor receives 2D images from cameras (up to 16 cameras) and converts then to 3D video format for space-multiplexed 3D display. It can cope with various arrangements of 3D camera systems (or pixel arrays) and resolutions of 3D display. Tn order to verify the functions of 3D video Processor. some evaluation-board were made with five FPGAs.

• Proceedings of the Korea Institute of Convergence Signal Processing
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• 2000.08a
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• pp.65-68
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• 2000

In this paper, as a compatible software radio transmission system, Digital-Radio conversion system which can directly change the digital signal generated by the logic circuit into radio signal is proposed. By the vector synthesis method, the digital signals can change directly into radio signal. If such a circuit is realized, RF circuit and an antenna can be composed by the simple one device, and the radio is directly controlled and performed by the software processing which is the essence of software radio. This Digital-Radio conversion system of this paper give many number of communication channels being offered by PN code and offer a hardware design flexibility by digitization, therefore it decrease the percentage ratio of hardware of system and give a more flexible function of software basis. In this paper, this proposed Digital-Radio conversion system is called D/R converter, and the principle of this D/R converter, radio signal generation algorithm is explained and the performance characteristics of proposed algorithm is shown in time base by the computer simulation method.

• The Journal of the Korea institute of electronic communication sciences
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• v.16 no.6
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• pp.1175-1182
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• 2021

The receiver of each radio telescope of KVN, has a sampler that converts astronomical radio signal to digital data. The ability of this sampler (the bandwidth, sampling frequency, and sampling bits) is improved by sqrt(n), if the bandwidth is increased by n times, and the number of observable objects increases exponentially in the case of continum spectrum radio sources. As the bandwidth increases, there are the more spectrum lines that can be simultaneously monitored in the radio source. This will greatly expand the research area in astronomical radio observation. For this reason, we are trying to independently develop the technology of the fast digital sampler. Therefore, based on the research experience and technology accumulated so far, An ability of sampling up to 3.5 GHz, that can vary the sampling frequency and can observe in a wider band, was designed and made for proto-type. In this study, we introduce the development details and test results for new sampling system.

• Journal of the Korean Society for Precision Engineering
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• v.23 no.5 s.182
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• pp.77-84
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• 2006

This paper describes the design and implementation of a robot's gripper control system. In order to safely grasp an unknown object using the robot's gripper, the gripper should detect the force of gripping direction and the force of gravity direction, and should perform the force control using the detected forces and the robot's gripper control system. In this paper, the robot's gripper control system is designed and manufactured using DSP(Digital Signal Processor), and the gripper is composed of two 6-axis force/moment sensors which measures the Fx force(force of x-direction), Fy force, Fz force, and the Mx moment(moment of x-direction), My moment, Mz moment at the same time. The response characteristic test of the system is performed to determine the proportional gain Kp and the integral gain Ki of PI controller. As a result, it is shown that the developed robot's gripper control system grasps an unknown object safely.

• KSCI Review
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• v.15 no.1
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• pp.225-228
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• 2007

컴퓨터 영상 화면을 아날로그 음성영상신호로 변환한 후 무선으로 송신하여 처리하기 때문에 해상도가 낮아 화질이 떨어진다. 또한 대형프로젝션TV에 보낼 영상화면의 단말기 RGB포트에 게이트웨이를 직접 연결해야 하는 불편이 따른다. 이러한 문제를 해결하기 위하여 이 논문에서는 IEEE802.11b/g 무선네트워크 기반에서 대용량 영상데이터를 최대 54Mbps의 속도로 송수신할 수 있는 무선통신시스템 개발과 이를 게이트웨이에 적용하여 영상데이터까지 무선으로 처리할 수 있도록 하는 장치를 개발하고, 대용량 영상데이터 송수신 처리 소프트웨어를 개발한다.

• Korean Journal of Crystallography
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• v.8 no.1
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• pp.38-47
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• 1997

A new weighing sensor for the automatic diameter control system of the crystal growth is developed in this study. This weighing sensor measures the frequency of the vibrating element which is lineally changing with respect to weight. The signal and the power of this system are transmitted without any physical contact, so that this sensor offers high accuracy and resolution. This system consists of a string, a sinusoidal wave generator, an automatic amplification adjusting circuit, signal transformers and a PCB. 4 kinds of programs are developed for checking DAC, weight calibration and controlling growth process. The measurements of the standard deviation and the resolution show $\pm0.10g$(measured at every second) and $5{\times}10^{-5}$, respectively, This weighing sensor is effective under high pres-sure of 200 atm, high temperature and vacuum condition. The weighing system can control the temperature in the accuracy of $\pm0.025^{\circ}C$ with the 'signal divider'. The optical quality single crystals of $(YGd)_3Sc_2Ga_3O_{12},\;Er-Y_3Sc_2Al_3O_{12},\;and\;Bi_{12}GeO_{20}$ have been grown by Czo-chralski method using this auto-diameter control system.