• Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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• 2001.02a
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• pp.189-192
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• 2001

In order to design thermally trigger controlled persistent current switch (PCS) for superconducting magnet system, it is very important to know information of applied adiabatic method and condition to get designed resistance and characteristics In this paper, we used cotton-gummed tape as thermal insulator and derived experimentally averaged thermal conductivity of it around 10K on the assumption that adiabatic structure of PCS is shape of pipe. The result value is about 0.29 W/mK and it is verified reasonable value by computer simulation and experiment of test PCS. Test PCS was designed and manufactured different dimensions. The experimental results of test PCS were in good agreement with the calculated results.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.33A no.5
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• pp.10-23
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• 1996

In this paper, the reverse link performance evaluation with synchronous CDMA is analyzed in the PCS system, which is the schem based on proposed method of KMT-PCS to increase the capacitance of cellular CDMA system. We make the baseband system model of CDMA reverse link, and then analyze system performance and subsystem techniques considering effect of channel and power control that are improtant factor influencing system performance in the PCS system. Based on this result, the paper presents primary technique analyses required at synchronous reverse link proposed by the KMT, which compose of initial synchronization range in initial synchronization step and control signal period in the synchronization maintenance step.

• Proceedings of the IEEK Conference
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• 1999.06a
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• pp.203-206
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• 1999

This paper describe the design and fabrication of a Multilayer helical antenna for PCS cellular phone. It has been designed for commercial PCS cellular phone by HP-HFSS and fabricated with diameter of 7.6mm and height of 9mm. As a result, the antenna was well-operated in the frequency ranges of 1.75~1.87㎓ for the application of PCS system. We obtained omni-directional radiation pattern, gain of -0.9㏈i and bandwidth of 180MHz.

• Proceedings of the IEEK Conference
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• 2001.06a
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• pp.189-192
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• 2001

In this paper, We designed and implemented 20 watt high power amplifier which can be used for the commercial services in band of 1.86 ~ 1.870Hz at PCS. In order to satisfy ACPR, We designed by using the ADS(Advanced Design System)ver1.3. The HPA is fabricated on tepron substrate($\varepsilon_{{\gamma}}$ =3.15, H=0.78mm, T=0.02mm). The implemented HPA measured The ACPR characteristics at $\pm$ 885kHz, $\pm$ 1.25MHz, $\pm$2.25MHz. The HPA meets specification with good ACPR. The HPA is expected to use as a commercial product of PCS base station.roduct of PCS base station.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2003.11a
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• pp.473-477
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• 2003

In this paper, a integrated structure of a two-element microstrip patch antenna with two feeds for GPS/PCS dual-band operation is proposed. The radiating element for PCS operation is a novel broad band low-profile cylindrical monopole top-loaded with a shorted meander patch, which gives linearly polarized conical radiation pattern and size reduction of patch due to meander line. The radiating element for GPS operation is a novel square-ring microstrip patch with truncated corners and slits. which provide circularly polarized broadside radiation patterns and size reduction due to slots. using dielectric substrate in GPS antenna of proposed antenna provide to improve isolation between two feeds and reduce size of patch. The proposed antenna achieves the bandwidth and polarization requirements of GPS and PCS systems.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.9
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• pp.1563-1571
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• 2008

In this paper, dynamics modeling of a PEMFC is performed by electro-chemical equations. The developed PEMFC simulation model is implemented using MATLAB Simulink in order to design an optimal PCS for fuel cell systems. In addition, by use of the developed model as an input source of PCS, the validity of the proposed dynamic characteristic model of the PEMFC is verified by various simulation and experimental results.

• Proceedings of the Korean Information Science Society Conference
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• 1999.10c
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• pp.694-696
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• 1999

최근에는 Non-PC 디바이스들을 위한 Embedded OS들이 PCS, PDA, 핸드헬드(Handheld) 컴퓨터, 터미널, 산업용 제어기 및 다른 소형 컴퓨터에서부터 인터넷 TV, 디지털 셋탑 박스, 웹폰, 인터넷 디바이스, 및 Mobile Computing 분야에 이르기까지 다양한 분야에서 그 요구가 급증하고 있다. 현재 이러한 응용들은 사용자의 응답시간이 빠른 표준 API(Application Programming Interface)의 사용을 필요로 한다. Window System의 Application을 개발하기 위해서는 보통 Win32 API를 사용한다. 그런, Win32 API에서 제공하는 자료형과 관련 함수들이 크기가 크고 속도가 느려서 소형의 적은 메모리와 빠른 속도를 필요로 하는 PCS 단말기에는 적합하지가 않다. 따라서 기존의 API의 기능을 충실히 수행하면서 PCS에 최적화된 API에 대한 연구가 필요하다. 본 논문에서는 PCS 정보단말기용 소형 운영체제에 적합한 API를 GWES(Graphics, Windowing, and Events Subsystem) 모델을 기반으로 설계하였으며 사용자 응답시간 지연을 해결하기 위해서는 Event 처리를 최소화하는 다중 메시지 처리 방식을 개발하였다.

• The Transactions of the Korean Institute of Power Electronics
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• v.15 no.1
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• pp.60-68
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• 2010

Recently, Power Conditioning System (PCS) tends to require more compact, higher efficiency and power density with better performance. A novel topology consisted of LLC resonant inverter and Low Frequency (LF) cyclo-converter for connecting to utility line is able to meet these requirements. The technical operating analysis is described and 1kW prototype is tested and verified the performances through connecting the 110Vac 60Hz utility line. Efficient results are described.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.34S no.3
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• pp.1-11
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• 1997

Since the radio spectrum is limited, future wireless system will have micro cellular architecture in order to provide multimedia traffic services on personal communicatons network. The small coverage area of micro cellular systems results in frequent hadnoffs and location updates. We focuse on network load and terminal power due to frequent location updates and propose a location tracking scheme using embedded-pager PCS terminals. The proposed scheme is expected to minimize theconsumption of PCS terminal powr and improve the receiving rate of callee because of the power saving mechanism and the embedded-pager PCS terminal. This paper proposes signaling flows among the network elements for the proposed location tracking scheme. The signaling flows are accomodated to not only the existed network architectures but alsothe ATM backbone network arcitecture. To verify the signaling flows, we used petri-Net model. The resutls show that the signaling flows are suitable to our proposed location tracking scheme.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.5 no.4
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• pp.817-821
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• 2001

In this paper, we design a microstrip patch antenna using 3-dimensional microstrip transition with the VSWR 1.3 over the PCS band (1.75 -1.87 GHz). We study experimentally the effect of the antenna parameters on antenna input impedance. And using the proposed antenna, we fabricate a polarization diversity any antenna and discuss the possibility of antenna for PCS base station.