• Korean Journal of Optics and Photonics
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• v.25 no.3
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• pp.150-154
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• 2014

The conditions under which a composite retarder consisting of two different retardation plates can be operated as a tunable quarter-wave plate are derived. The explicit expressions for the azimuthal angle of a linear polarizer and those of two retardation plates to generate circularly polarized light are presented as a function of retardation angles. Those expressions for the azimuthal angles derived using the Jones matrix formalism are verified as identical to the expressions derived from the analysis of the trajectory on a Poincar$\acute{e}$ sphere. A couple of examples are presented for generating circularly polarized light when two identical retardation plates are used.

• Journal of Korean Society for Quality Management
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• v.5 no.1
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• pp.20-22
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• 1977

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2001.10a
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• pp.138-143
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• 2001

Based on mild slope equation and parabolic approximation the forward diffraction of monochromatic waves by a straight breakwater are studied numerically. The characteristics and effects of stem wave along breakwater and the relations between the stem wave and incident wave angle are discussed.

• Proceedings of the Korean Information Science Society Conference
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• 2001.10b
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• pp.64-66
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• 2001

현재 VoD 시스템은 마이크로소프트(Microsoft Corporation)에서 제공하는 WMS(Windows Media Server)를 사용하여 많이 구축하고 있다. 이 때 시스템의 QoS는 WMS의 성능에 크게 의존하기 때문에 WMS 의 성능을 동적으로 분석할 필요가 있다. 본 연구에서는 WMS 의 성능 분석을 위해 제안된 에이전트 시스템 모델(agent system model)에서 WMS와 인터페이스를 하는 에이전시(agency) 부분을 개발한다. 에이전시는 WMS가 클라이언트들에게 스트림 서비스를 제공하는 과정을 모니터링하고, 성능 분파에 필요한 데이터를 수집하여 저장하고, WMS 가 성능 향상을 위해 필요한 조치를 실행하게 한다.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.4 no.2
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• pp.72-82
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• 1992

To accurately estimate nearshore current in shallow water regions. it is necessary to investigate the irregular wave transformation characteristics and radiation stress produced by random sea waves. This research is to investigate the application or the individual wave Analysis Method. the Component Wave Analysis Method and Representative Wave Analysis Method in the shallow water region. These methods were estimated by wave shallowing transformation when the waves propagate from deep water to shallow water region b)r generating regular waves, two component waves and irregular waves (Bretschneider-Mitsuyasu type). That is, the Indivisual Wave Analysis Method is to investigate from the viewpoint of shallow water transformation of wave statistical characteristics and their zero-down-crossing waves (wave height period and wave celerity). And the component Wave Analysis Method is to investigate from the view point of shallow water transformation of basic frequency component wave and their interference frequency component wave. In addition, this research is to compare the measured mean water level elevation with the calculated one from radiation stress of irreguar waves that is assumed in the three methods above.

• Journal of Sasang Constitutional Medicine
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• v.11 no.1
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• pp.41-61
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• 1999

The purpose of this article is to investigate Lee Je-rna'os viewpoint of Morpho-Image. In the first place, I will define the viewpoint of Morpho-Image as the the structure of recognition and study it through bibliographic study on Lee Je-ma's work. The conclusions summarized as follows; 1. The structure of recognition, represented in "Gyukchigo(格致藁)" "Dongyi Soose Bowon Sasang Chobonkyon(東醫壽世保元四象草本卷)", is based on Taigi(太極), Liangyi(兩儀), Sasang(四象). There are the mind of Taigi(太極), the mind of Liangyi(兩儀) separated from Taigi(太極), the mind of Sasang(四象) separated from Liangyi(兩儀). The mind of Taigi(太極) is the mind of center, the mind of Liangyi(兩儀) is the mind of the mind and body(or the wisdom and action). Two axis, the mind(or wisdom) and the body(or action), cross and make Sasang(四象), affair-mind-body-object which classifies all affairs and objects of humans, society, and the universe as four types. 2. Lee Je-ma summarized everything in view of Sasang(四象), Sasang(四象) in view of Liangyi(兩儀), Liangyi(兩儀) in view of Taigi(太極). 3. The procedure of recognition above is described in , , . Such is transformed in terms of human body and described in .

• Journal of the Korean Institute of Telematics and Electronics A
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• v.28A no.1
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• pp.15-22
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• 1991

New design method of small-sized 3-dB $0^{\circ}/180^{\circ}$ ring hybrid and Wilkinson power divider using both lumped elements and distributed elements are presented. At the center frequency of 900 MHz 3-dB $0^{\circ}/180^{\circ}$ ring hybrid and Wikinson power divider are designed and tested. Good agreements are obtained between measured and theoretical modeling results, and at the same time the circuit area is reduced by more than 70% compared with the discributed-type circuits.

• Korean Journal of Optics and Photonics
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• v.18 no.1
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• pp.84-89
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• 2007

Bell states have been investigated in a Hong-Ou-Mandel interferometer using photon pairs from a type-1 SPDC. The four kinds of the Bell states, $|{\Psi}^+>,|{\Psi}^->,|{\Phi}^+>,|{\Phi}^->$ are created by placing 2 HWPs, 2 QWPs at outputs of the interferometer. They show an average visibility of 77% in the coincidence measurement.

• Transactions of the Korean Society of Mechanical Engineers
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• v.17 no.12
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• pp.3166-3178
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• 1993

The turbulent flow characteristics of impinging jet have been investigated by the hot wire anemometry with a movable impinging wall. Turbulences were generated by the meshed jet as well as the typical round jet and their characteristics were compared, of mean velocity profiles, turbulent intensities. Reynolds stresses, similarities and their centerline flow behaviors. The meshed jet tends to make shear layer wider than the normal one in the initial region and the velocity profiles of the normal jet is rather contractive being compared with those of the meshed one near the wall. The effect of meshed exit appears only within 4D at the begining of jets and the cascading process of the meshed one marches more rapidly than that of the normal jet. The wall effects appear in the downstream of about 0.85 H to the impinging wall for every case of wall positions in both nozzles.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2004.05b
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• pp.655-657
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• 2004

채널 레벨 컨트롤러는 DWDM(Dense Wavelength Division Multiplexing) 방식의 OXC(Optical Cross Connect), OADM(Optical Add/Drop Multiplexer), 광 증폭기(EDFA : Erbium Doped Fiber Amplifier) 둥의 시스템에서 채널별 광신호의 세기를 조절하여 시스템의 신뢰성을 높이는 중요한 제어기다. 본 논문에서는 12채널 VOA(Variable Optical Attenuator) 4개를 사용하여 40채널의 광 신호 레벨을 제어할 수 있는 컨트롤러를 구현하였다. 각 채널의 광 신호 레벨을 제어하는데 하나의 마이크로 프로세서가 5개의 채널을 제어하고 총 8개의 마이크로프로세서로 40채널을 분산 제어하도록 구성하였다. 또한 외부와 통신을 하고 사용자로부터의 명령을 각각의 마이크로프로세서에 전달하기 위한 마이크로프로세서를 추가하였으며, 출력되는 광 신호의 세기를 측정하여 VOA를 제어하는데 있어서 VOA 출력에서 바로 PD(Photo Detector)로 입력하여 AWC(Arrayed Waveguide Grating) 출력에서 광 신호를 다시 분파하여 PD에 입력하는 번거로움을 개선하였다.