• 한국연소학회:학술대회논문집
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• 2000.12a
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• pp.160-167
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• 2000

We investigated a uniform temperature zone, produced by double flame structure of a coflow CH4/air partially premixed flame, to be used as a temperature calibration source for laser diagnostics. A broadband N2 CARS(coherent anti-Stokes Raman spectroscopy) system with a modeless laser was used for temperature measurement. When the stoichiometric ratio was 1.5, we found the uniform temperature zone in radial direction of the flame of which the averaged temperature was 2110 K with standard deviation 24 K. In the stoichiometric ratio range between 2.0 and 2.5, we found very stable temperature-varying zones in vertical direction at the center of the flame. The size of the zone was approximately 15 mm and it covered a temperature range from 300 K to 1900 K. We also suggest that this zone can be used as a calibration source for 2-D PLIF(planar laser induced flurescence) temperature measurement.

• Journal of Satellite, Information and Communications
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• v.8 no.4
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• pp.12-16
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• 2013

This paper we introduce operated public test-bed satellite system configuration for satellite communications and usage for services via COMS(Communication, Ocean and Meteorological Satellite). According to trial public test-bed operation, the broadband multimedia services are expected to be available at the next generation VSAT services due to the increasing of Ka-band utilization. In addition, UHD broadcasting services via satellite is expected to improve the universal accessibility of broadcast services.

• Satellite Communications and Space Industry
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• v.13 no.1 s.28
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• pp.118-124
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• 2006

HAPS(High Altitude Platform Station) which is defined as a station located on an object at an altitude of 20 to 50 km and at a specified, nominal, fixed point relative to the earth is promising technology capable of providing broadband multimedia services. In this study, economical aspects of HAPS service are analyzed by estimating the revenue and costs incurred by the service. To evaluate the profitability of HAPS service, the number of subscribers is estimated and then the net present value (NPV), payback period, and the rate of return on investment (ROI) are calculated under various scenarios

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.28 no.3
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• pp.51-56
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• 2014

The flat power spectrum of the transmitter output signal for the desired frequency range is ideal to achieve the best performance of ultrashort pulse reflectometry. However, the power spectrum of a typical pulse generator decreases significantly as frequency increases. A configuration of three chirped waveforms was employed to improve the power spectrum of the transmitter signal at higher frequencies. To determine the amplification gain required for higher frequency components, three chirped waveforms were theoretically generated and their power spectra were measured using numerical band-pass filters. Based on the results of numerical computations, the three chirp configuration was successfully applied to the design of the transmitter for a broadband system.

• Proceedings of the KIPE Conference
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• 2008.06a
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• pp.174-176
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• 2008

국내 원격검침시스템은 전기, 가스, 수도 사업자가 독립적으로 시스템을 개발하고 있어 각 검침시스템간의 상호운영성을 보장하지 못할 뿐만 아니라, 원격검침시스템 개발에 대한 중복투자가 이뤄지고 있다. 고속전력선통신 기반의 통합검침시스템을 구축하고 통신프로토콜을 통일하게 되면 각 사업자별 검침용 통신비를 절감할 수 있을 뿐만 아니라, 장비의 유지보수 비용도 절감할 수 있어 저비용으로 효율적인 원격검침이 가능하게 될 것으로 예상된다. 본 논문에서는 전력선통신기반의 통합검침 시스템의 구성과 설계된 통합검침시스템의 성능을 검증하기 위한 실증시험망 구축결과에 대해 소개한다.

• Proceedings of the Korea Information Processing Society Conference
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• 2007.05a
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• pp.1453-1456
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• 2007

본 논문은 안정적인 품질을 제공하고 개방된 외부 인터페이스를 통해 외부 시스템등과도 연동이 손쉽게 되며 다양한 형태의 문서들(doc, hwp, pdf, jpg 등)과 동영상에 대한 공유가 가능한 통합 공유 시스템 개발에 관한 것으로 타 공유 솔루션보다 확장성, 안정성, 기능성 면에서 차별화 되는 특징을 가지며 사업 현실에 적용이 유리한 이점을 제공한다. 또한 BcN(Broadband Convergence Network)서비스의 중심에 있는 IMS(IP Multimedia Subsystem)와 연동되게 구성 되어 있으므로, 3rd 파티 어플리케이션의 이식도 가능하여 새로운 번들형 서비스를 손쉽게 만들어 낼 수 있고 그 개발비용을 최소화 하여 유사 솔루션에 대한 가격 경쟁력을 쉽게 확보할 수 있는 이점을 수반한다.

• ETRI Journal
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• v.29 no.6
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• pp.725-735
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• 2007

This paper describes a line element planar antenna with three frequency bands. To obtain broadband characteristics, a modified planar antenna that has semi-elliptical elements based on the characteristics of a line element planar antenna is proposed and analyzed by the finite difference time domain method. Return loss characteristics are discussed as functions of the eccentricity values of semi-ellipse at each element. The broadbanding of the modified planar antenna is implemented based on the results. The planar antenna with three systems (an 800 MHz band cellular phone, a third-generation cellular phone, and a 2.4 GHz band wireless LAN system) is considered as an application example.

• Proceedings of the IEEK Conference
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• 1998.06a
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• pp.38-41
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• 1998

Due to the increasing demand to multimedia services over wireless communication network, LMDS(Local Multipoint Distribution Service) has been proposed as an alternate approach for broadband wireless access network. But LMDS, Which uses the mmwavelength radio spectrum, has been limited for unknown microwave frequency characteristics. In this paper, we analyze the parameters related to the system design on 28GHz frequency: Propagation path loss and rainfall attenuation. Based on these analytical results, the proper cell size in Korea is determined. We also analyze the bit error rate and frame loss rate for various kinds of digital modulation schemes(QAM 4, 16, 64, 256). Finally, we apply to ㅍ service to evaluate a call blocking rate, efficiency and channel capacity.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2000.05a
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• pp.348-351
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• 2000

In order to enact the technical standard of RF(Radio Frequency) in domestic, this paper analyzes the trends and the technical specifications of high performance radio local area network, for example HIPERLAN(Europe), U-Nll(U.S.A), broadband mobile access system(Japan). The contents of this paper are helpful to make a rule for the desirable national technical standard of high performance radio local area network.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.16 no.9
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• pp.809-818
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• 1991

We investigate the onsiderations of design issues for a bradband ATM network. Three kimds of network design requirement are considered ; user grade-of-service(GOS) requirements. Network manager requirements, and system designer requirements. In this work, e are focusing on the balancing problems among performance measures. We suggest that design parameters for a bradband ATM echange would be tuned within the acceptable sets by a layering concept on the peformance objectives.