• Journal of Broadcast Engineering
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• v.12 no.1 s.34
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• pp.11-27
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• 2007

T-DMB(Terrestrial-Digital Multimedia Broadcasting) for portable and mobile broadcasting service was officially launched in the metropolitan area of Korea in December 2005. The development of interactive data services and the expansion of T-DMB network have been now progressed, and the regional T-DMB broadcasters will be selected in the near future. Although it is important to evaluate service area and reduce a fringe area for optimizing RF coverage of T-DMB, there was no professional system to support those works, and therefore lots of resources in budget, manpower and time were required. The measurement considering characteristics of SFN(Single Frequency Network) is essential in the implementation of T-DMB network which needs to control synchronization, spacing and output power of transmitters. In addition, mobile measurement, enough measured parameters for many-sided analysis of reception quality, efficient management of enormous measured data and representation of measured results on the electronic map are also important in evaluating service area. In this paper, we derived requirements for a new measurement system in T-DMB by considering the above details, and we proposed and developed an integrated measurement and analysis system. The developed system was applied to the implementation of T-DMB network of KBS and field tests, and it proved its efficiency and accuracy in result.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.11 no.6
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• pp.289-294
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• 2011

In this paper, we developed a phone call display system or "alimi" for displaying the received phone data at limited space that can not carry a mobile phone and and its validity was confirmed. It consists of a data communication application transmitting the phone data via bluetooth, a RF data repeater to extend the range of data communication, and a display system part for displaying the received phone data to the phone user. It has economy in terms of system installation because the implementation of the proposed system is simple and low cost installation is possible. As ordinary mobile phones users using the system can easily utilize it by downloading the application on the app. store, it has economy and convenience checking whether a call is received.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.18 no.3 s.118
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• pp.315-322
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• 2007

In this paper, active integrated antenna with left hand circular polarization(LHCP) for a transmitter of UHF RFID reader has been described. A novel rectangular ring patch as a radiator of the active antenna is proposed for easier impedance matching, smaller patch size, and LHCP characteristics. An amplification circuit is placed in the opening area of the radiator and is combined with it to work as oscillating circuit around 915 MHz. From the test results, impedance bandwidth of 29 MHz, 3 dB axial ratio bandwidth of 20 MHz, 3 dB beamwidth of 85 degree, and effective radiation power of 8.8 dBm have been obtained.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.15 no.7
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• pp.661-668
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• 2004

A novel method to reject the spurious signals which are occurred at Weaver-type low-IF transmitter was proposed in this paper. The spurious signals are generated by the gain and phase imbalances of I/Q channel or imperfect characteristics of 90$^{\circ}$ phase shifter in local oscillator for I/Q channel source. By deriving the gain and phase-based functions from RF spurious signal with the channel imbalance information, the lie channel imbalances were deduced as functions with magnitude and sign dependent on I/Q channel imbalance degree. The proposed method compensates the estimated I/Q channel imbalances by correlation values between the down-converted signal obtained by squaring the output signal itself using a simple mixer and the modified baseband signal. By comparing two signals after A/D conversion, the magnitude and sign of each type of imbalances can be determined separately and simultaneously. Based on the I/Q channel imbalance compensation, the spurious signals can be reduced by adjusting the gain and phase values of I or Q channel signal. The way to estimate the channel imbalances of the up-conversion mixer was presented and verified by using theoretical derivations and computer simulations.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.11A
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• pp.1661-1671
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• 2000

본 고에서는 한국통신(Korea Telecom) IMT-2000 시험시스템(이하: Trial system 라고 함) 단말기용 전력증폭단으로 적용하기 위한 다단구동증폭기 및 전력증폭기를 GaAs MMIC로 설계 구현하는 기술을 제시하였다. 설계된 구동증폭기는 3단으로구성하여 RF(Radia Frequency) 송신신호(1955$\pm$70MHz)대역에서 2단 (중간단)의 이득 조정범위가 40 dB이상이 될 수 있도록 능동부품인 MESFET를 Cascade 형으로 구성하고 MESFET의 게이트(gate)에 조정전압을 인가하는 증폭기를 설계하여 GaAs MMIC화 1 침(크기4$\times$5 mm)으로 제작하였다. 아울러, 본 논문에서는 제시한 구동증폭기는 동작주파수 대역폭 범위기 3.5배이고 출력전력은 15dBmm 이며, 출력전력이득이 25~27dB이고 반사계수는 -15~20dB이며 이득평탄도 3dB(동작주파수 대역폭내)로써 Trial system용 단말기의 최종단인 전력증폭단의 출력단 특성을 효과적으로 나타내었다. 그리고, 전력 증폭기는 2개의 입력단에서 출력되는 신호를 분배하는 전력분배기와 병렬구조인 4개의 증폭단에서 출력되는 출력신호를 외부에서 접속하는 전력결합기를 접소하여 구성하였으며 RF(Radio Frequency) 주파수(1955 $\pm$70NHz)에서 대역폭을 4배로 설계하여 광대역인 대역폭을 구현하였고 출력전력은 570mW이며, 출력부가효율(PAE; Power Added Efficency)가 -15$\pm$20dB이고, 이득 평탄도(Gain flatness)는 동작주파수 대역내에서 0.5dB이며 입출력 전압정재파비(Input & Output VSWR)가 13이하인 고출력 전력증포기를 GaAs MMIC화 1칩 (크기; 3$\times$4mm)으로 제작하였다.의 다양성이나 편리성으로 변화하는 것이 국적을 바꾸는 것보다 어려운 시 대가 멀지 않은 미래에 도래할 것이다. 신세기 통신 과 SK 텔레콤에는 현재 1,300만명이 넘 는 고객이 있으며. 이들 고객은 어 이상 음성통화 중심의 이동전화 고객이 아니라 신세기 통신과 SK텔레콤이 함께 구축해 나갈 거대란 무선 네트워크 사회에서 정보화 시대를 살아 갈 회원들이다. '컨텐츠의 시대'가 개막되는 것이며, 신세기통신과 SK텔레콤은 선의의 경쟁 과 협력을 통해 이동인터넷 서비스의 컨텐츠를 개발해 나가게 될 것이다. 3배가 높았다. 효소 활성에 필수적인 물의 양에 따른 DIAION WA30의 라세미화 효율에 관하여 실험한 결과, 물의 양이 증가할수록 그 효율은 감소하였다. DIAION WA30을 라세미화 촉매로 사용하여 아이소옥탄 내에서 라세믹 나프록센 2,2,2-트리플로로에틸 씨오에스터의 효소적 DKR 반응을 수행해 보았다. 그 결과 DIAION WA30을 사용하지 않은 경우에 비해 반응 전환율과 생성물의 광학 순도는 급격히 향상되었다. 전통적 광학분할 반응의 최대 50%라는 전환율의 제한이 본 연구에서 찾은 DIAION WA30을 첨가함으로써 성공적으로 극복되었다. 또한 고체 염기촉매인 DIAION WA30의 사용은 라세미화 촉매의 회수 및 재사용이 가능하게 해준다.해준다.다. TN5 세포주를 0.2 L 규모 (1 L spinner flask)oJl에서 세포간의 응집현상 없이 부유배양에 적응,배양시킨 후 세포성장 시기에 따른 발현을 조사한 결과 1 MOI의 감염조건 하에서는 $0.6\times10^6$cell/mL의 early exponential시기의 세포밀도에서 72시간 배양하였을 대 최대 발현양을 나타내었다. 나타내었다. $\beta$4 integrin의 표현이 침투 능력을 높이는 역할을 하나 이때에는 laminin과 같은 리간드와의 특이

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.38 no.2
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• pp.195-199
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• 2010

(255,223) RS(Reed-Solomon) code which is the CCSDS(Consultative Committee for Space Data Systems) standard was used in the STSAT-3 to correct errors during the downlink of payload data. The RS encoder developed by VHDL was implemented in MMU(Mass Memory Unit). Moreover, the RS decoder developed by C-language was implemented in the DRS(Data Receiving System) of ground station. In this paper, we reported the design and analysis results of RS(255,223) for STSAT-3. The BER(Bit Error Rate) performance from MMU to DRS was confirmed through the downlink test at 16 Mbps. Also, the error correction performance and capability of RS(255,223) was tested by the manual attenuation of the RF(Radio Frequency) signal in the X-band transmitter resulting in putting some errors in the communication line.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.17 no.3
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• pp.183-188
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• 2017

This paper is for the a study on home healthcare system for a patient using SAW Tag. This system is useful when there's a patient in home. Many patients are wounded in restroom. But restroom is very private place and nobody want to be disturbed here. The place where the patient is most injured in the house is the toilet, and it is the point where the privacy of the individual should be kept and the patient's condition should be checked and cope with in case of emergency. And using saw tag, we can calculate position and ID through reflected rf signal. Therefore we propose a general home healthcare system. The management system utilized a seat bed system to monitor at-home patients. The system mounts a bio-signal measuring unit on a toilet seat, measures a bio-signal from the bio-signal measuring unit, and the measured bio-signal is transmitted to the main server through the user's smart phone. With proposed system, we can expand operation area to silver town where many patients are cared. In this paper we developed sensor system and saw tag positioning system and showed the result.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.7
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• pp.292-299
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• 2013

In this paper, we developed a data transmission system over coaxial cable based on the IEEE 802.15.3 MAC and Ultra-Wideband(UWB) Physical Layer. This system is capable of operation in both wireless and wired medias. When operating on coax cable it is capable of Gigabit bi-directional data rate operation on in-home coax wiring and over Hybrid-Fiber-Coax(HFC) cable infrastructure. The developed system transceives command, control and data over a 75 ohm coax system in a home or office. This system operates at a center frequency of 4GHz with a total occupied bandwidth of 1.33Ghz centered on 4GHz. The system uses BPSK modulation and sends symbols at a maximum power level of +15dBm. It has been tested and works through up to three CATV RF splitters in a home environment.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.34 no.2
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• pp.135-138
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• 1998

This paper describes the construction and experimetal results of prototype digital telesounder developed to monitor remotely the fish school entered in setnet. The telesounder consists of the sea station and land station. The former consists of an ultrasonic transceiving part of 50 KHz, a hand made 16 bits single board computer (SBC), and a RF MODEM of 9600 bps for data link. The SBC controls the trigger signal to transmit the ultrasonic pulse, maximum detection range, sampling rate in analog to digital converter and data link. The sampling rate of echo data was 80 ${\mu}$s. The later consists of a RF MODEM same as the former one and 486 notebook computer which displays the echogram and saves its raw data. The authors carried out some experiments to confirm the practical use of the telesounder. At results the echogram obtained on the land station is sufficiently good and clear to monitor the behavior of fish school in setnet.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.23 no.6
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• pp.1602-1609
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• 1998

In this paper, the design and implementation of the novel RF front end circuit for CDMA based PCS phone is described. This novel scheme is realized by building the power amplifier module combined with duplexer. The dielectric filters which are parts of duplexer are broken up and relocated into the module. Electromagnetic analysis for via holes and coupling between narrow transmissio lines is icluded to design a circuit. The combined moule has been minimaturized to be as small as 1.5CC. It has satisfied IS-95 requirements for linearity performances of CDMA signal at 24-dBm output power as well as played apart as a duplexer. The operating current of about 95mA has been saved owing to both rearranging dielectric filters and limiting operating point to class-B by considering real working power range of CDMA phones.