• Journal of IKEEE
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• v.15 no.2
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• pp.179-189
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• 2011

This paper presents an SVC based multi-channel transmission technique. Transmission of high definition multimedia and its service efficiency can be significantly improved by the proposed method. In this method, the HD stream is divided into the two layer streams, i.e., a base layer stream and an enhancement layer stream. The divided streams are transmitted through a primary channel and an auxiliary channel, respectively. The proposed technique provides a noble mode switching technique which enables a seamless service of HD multimedia even under the conditions of abrupt and intermittent deterioration of the auxiliary channel. When the enhancement layer stream is disrupted by the channel monitoring in the mode switching algorithm, the algorithm works further to maintain the spatial and time resolution of the HD multimedia by upsampling and interpolating the base layer stream, consequently serving for the non disrupted play of the media. Moreover, the adoption of an adaptive switching algorithm significantly reduces the frequency of channel disruption avoiding the unnecessary switching for the short period variations of the channel. The feasibility of the proposed technique is verified through the simulation study with an example application to the simultaneous utilization of both Ku and Ka bands for HD multimedia broadcasting service. The rainfall modeling and the analysis of the satellite channel attenuation characteristics are performed to simulate the quality of service performance of the proposed HD broadcasting method. The simulation results obtained under a relatively poor channel (weather) situations show that the average lasting period of enhancement layer service is extended from 9.48[min] to 23.12[min] and the average switching frequency is reduced from 3.84[times/hour] to 1.68[times/hour]. It is verified in the satellite example that the proposed SVC based transmission technique best utilizes the Ka band channel for the service of HD broadcasting, although it is characterized by its inherent weather related poor reliability causing severe limitations in its independent application.

• Proceedings of the KIEE Conference
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• 1999.07d
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• pp.1614-1616
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• 1999

Epoxy resin has been used as matrix resin of advanced composites owing to ideally suitable properties and inherent physical and chemical properties for electrical and electronic insulation. In this paper, in order to evaluate the performance of epoxy composites for out door insulation, variations of tracking resistance were investigated on the complex ageing parameter. Also, IPN methods were introduced in order to improve performance for out door use. As a result, it was confirmed that tracking resistance were degraded with complex ageing parameters. But, it was confirmed that specimen of IPN structure have the better tracking resistance properties than SIN structure by moisture absorption aging.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.96-99
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• 2005

Fiber optic connector, ferrule, is a device to connect and align fiber optics cable on fiber-optic communication system. In this paper, Structural analysis was performed to analyze bed and frame structure of co-axial grinding machine. Deformation and modal analysis for natural frequency was performed using ANSYS Designspace program to analyze structural characteristics. New improved model of bed and frame structure was proposed based on initial basic model.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.173-176
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• 2005

In this paper, a study on Web-based application using commercial CAE program, ANSYS is performed. Customized analysis, site or user oriented specific analysis, is suitable to user and user's demand who has little experience in structural analysis for specific CAE analysis. Customized analysis methodology using ANSYS Workbench SDK is presented through the web-based application. Case Studies of mobile phone about the implementation of web-based application are also presented as an example.

• Journal of Pharmaceutical Investigation
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• v.20 no.1
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• pp.1-5
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• 1990

Effect of an angiotensin inhibitor (AAS; loading dose of 25, 50, $100{\mu}g/kg$ and maintenance dose of 12.5, 25,$50{\mu}g/ka/hr$) on the pharmacokinetics of propranolol (4 mg/kg i.v.) was studied in rabbits. Plasma concentrations and relative bioavailability of propranolal increased upto 127-175% by AAS coinjection. The urinary excretion of propranolol decreased by AAS. Dosage regimen of propranolol should be adjusted when it is administered with AAS.

• Electronics and Telecommunications Trends
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• v.29 no.6
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• pp.1-13
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• 2014

GaN(Gallium Nitride)는 3.4eV의 넓은 에너지 갭으로 인하여 고전압에서 동작이 가능하고, 분극전하를 이용한 캐리어 농도가 높아 높은 전류밀도와 전력밀도를 얻을 수 있으며, 높은 전자 이동도와 포화 속도로부터 고속 동작이 가능하여 고주파 고출력 고효율 소형의 전력증폭기 소자의 재료로 적합하다. 본고에서는 민수 및 군수 겸용 Ku-대역 및 Ka-대역 GaN 고출력 전력증폭기(SSPA: Solid-State Power Amplifier)와 관련된 GaN 전력증폭 소자, GaN 전력증폭기 MMIC(Microwave Monolithic Integrated Circuit), 내부정합 패키지형 GaN 전력증폭기 및 GaN SSPA에 대하여, 국내외 특허 기술동향과 연구개발 기술동향을 중심으로 고찰하고자 한다. 국외의 GaN 고주파 고출력 전력증폭기 기술의 연구동향이나 특허동향을 심층분석하여 연구개발에 활용하고자 한다.

• 전기의세계
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• v.31 no.6
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• pp.445-449
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• 1982

This Paper describes the influence of additive concentrations and sintering temperature on the surge protection performance in ZnO ceramic varistors. It is found from the experiments that the metal-oxide semiconductors based oi ZnO with an additive incorporation of 0.50% molx(Bi$\_$2/O$\_$3/+MnO+CoO+Cr$\_$2/O$\_$3/+2Sb$\_$2/O$\_$3/) and sintered at 1250.deg. C present excellent V-I characteristics in view of transient surge suppression. Gapless arrester element with aluminum electrodes shows also good reliability against impulse shock and marks a low voltage clamping ratio(V$\_$1KA/V$\_$1mA/<2.0) compared with the conventional SiC varistors.

• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.331-332
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• 2008

A horn antenna having dual-band and dualpolarization operation is proposed. To implement a small-sized structure providing circular polarizations in the Ka- and K-band, the antenna is designed by using the horn radiator on the basis of a conical helix which is exited by two ports for TX and RX in both ends. Through a design optimization process, a compactdual-band and dual-polarized horn antenna having high gain and high isolation performance was realized.

• Journal of the Korean housing association
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• v.1 no.1
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• pp.65-76
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• 1990

Sugok Villiage. of the prospective flooded villiages for building Im Ha Dam, is selected as the studied place. Primarily, the purpose of this study is invested, recerded about traditional living environment, and then searched to find out possibilites on the context of the inheritance of analyzing about life contents and space. The result of this study are as follows:1) In composition of living environment, thinking view on confucianism and living view on folk beliefs are considered as important element2) Hierarchy of life environment is appeared of above and below space.(focused on JONG KA) and inner and outer space(boarded on pine forest) on the other hand according to living territory life environment can be divided into five territories.3) Confucian ideas, social status, folk beliefs and economics has been affected about formation of individual life. Accordingly, I believe that true inheritance of traditional culture was, through preserving mental contents as well as physical contents, possible.

• Journal of the Korean Applied Science and Technology
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• v.7 no.1
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• pp.49-62
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• 1990

In order to synthesize N,N-di-(polyoxyethylene) perfluoroacyl amines and the surface active monoperfluoroacyl aza crown ethers, it is performed as follow. Six of N,N-di(polyoxyethylene) perfluoro acyl amines were synthesized from perfluoroalkanoic acids with ethanol followed by oxyethylation with triethylene glycol mono chloride or tetra ethylene glycol mono chloride and six of N-perfluor acyl monoaza crown ethers by cyclization of corresponding N,N-di(polyoxy ethylene} perfluoro acyl amines with p-toluene suflonic chloride-NaOH/dioxane, p-toluene sulfonyl chloride KOH/dioxane and benzene sulfonic chloride-KOH/dioxane systems.