• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.9-10
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• 2011

본 논문에서는 자기 공명 방식의 무선전력전송과 기존의 전자기 유도 방식의 특성을 회로 해석에 K 인버터를 적용하여 비교하였다. K 인버터가 적용된 등가회로를 이용하여 시스템 효율과 임피던스 매칭 조건, 입 출력 전력 값을 유도하였다. 그 결과 최대 효율이 되는 임피던스 매칭 조건을 만족시키면 전자기 유도 방식과 자기 공명 방식은 서로 같은 효율로 전력전송이 가능하였다. 하지만 자기 공명 방식이 전자기 유도 방식에 비해 임피던스 매칭을 할 수 있는 자유도가 더 크고, 입 출력 전력 제어에 있어서 더 나은 장점을 가지고 있었다.

• 한국정보통신설비학회:학술대회논문집
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• 2007.08a
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• pp.50-54
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• 2007

현재 국내에서 ITS(Intelligent Transport Systems) 통신방식으로 이 용되고 있는 DSRC 방식은 TTA(한국정보통신기술협회)의 기술표준으로서 대전시,전주시에 적용되어 BIS(Bus Information Service)에 이용되고 있고,최근 고속도로 ETCS(Electronic Toll Collection System)가 DSRC방식으로 전국고속도로 Tollgate 에서 2007년 연말에 개통될 예정이다. DSRC 방식은 2000년에 TTA(한국정보통신기술협회)에서 기술표준이 제정되어 현재 1Mbps 의 Data 용량을 가진다. DSRC 방식의 물리링크 변조방식은 ASK(Amplitude Shift Keying)로 ITS 확장 서비스 적용을 위해 변조방식을 QPSK(Quadrature Phase Shift Keying )로 개선하게 되면 이론적으로 4배의 Data Rate 향상이 이루어진다. 물리적인 RF 변조방식을 ASK에서 QPSK로 바꿔 간단히 Data Rate을 개선하게 되면 회로구현의 경제성이 향상되어 DSRC 응용 서비스가 활성화 될 것이다.

• Proceedings of the Korean Information Science Society Conference
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• 2004.04b
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• pp.445-447
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• 2004

본 논문에서는 컴포넌트 기반 시스템 개발시 시스템간의 상호운용성을 높일 수 있는 방도를 제시하는데 있다. 다시 말하자면 다른 웹 서비스 방식과 분산 객체 방식의 컴포넌트 기반 시스템들의 상호운용 성숙 정도를 측정하려는 시도에 있다. 적용 사례에서는 클라이언트는 .NET 환경을 서버는 EJB 환경 상에서 개발된 EJB와 .NET 컴포넌트는 웹 서비스 방식과 IIOP.NET를 이용한 분산객체 방식 두 가지 방식으로 상호운용 하였다. 본 논문에서는 이 두 가지 상이한 상호운용 방식에 대하여 성숙도 모델인 LISI를 기반으로 상호운용 측정 기법을 적용하여 상호운용 능력을 측정하려 노력하였다. LISI 상호운용 능력을 측정한 결과 웹 서비스에 의한 방식이 분산 객체 방식보다 높은 상호운용 능력이 있음이 나타난다.

• The KIPS Transactions:PartC
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• v.12C no.5 s.101
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• pp.679-686
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• 2005

Because EPON access network shares a medium and aggregates the traffic from EPON subscribers, scheduling media access control on EPON bandwidth allocation is very important. Furthermore DBA mechanism of EPON based on TDMA is out of specification and up to implementation. This paper deals with a DBA method to guarantee the QoS of the delay sensitive traffic on the base of best-effort service and delay priority queue management. The proposed method performs virtual scheduling algorithm for the integrated traffic. It uses the same MAC messages and tries to guarantee the QoS of higher priority traffic first with a simple DBA architecture. We evaluate the algorithm for traffic delay according to polling interval and traffic load of upstream and downstream. The results show that the proposed method can guarantee the QoS of the delay sensitive traffic with priority of the service classes.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.40 no.6
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• pp.48-57
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• 2003

In this paper, An 8${\times}$l ID-IDCT processor with adder-based distributed arithmetic(DA) and bit-serial method Is presented. To reduce hardware cost and to improve operating speed, the proposed 8${\times}$1 ID-IDCT used the bit-serial method and DA method. The transform of coefficient equation results in reduction in hardware cost and has a regularity in implementation. The sign extension computation method reduces operation clock. As a result of logic synthesis, The gate count of designed 8${\times}$1 1D-IDCT is 17,504. The sign extension processing block has gate count of 3,620. That is 20% of total 8${\times}$1 ID-IDCT architecture. But the sign extension processing block improves more than twice in throughput. The designed IDCT processes 50Mpixels per second and at a clock frequency of 100MHz.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.11a
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• pp.429-432
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• 2008

Cathodic Protection Method was introduced as a corrosion protection method of metals under the ground or sea. Since 1970, it was applied to corrosion protection method of reinforced concrete structures. After 1990, this method has been used around the world, and its usability was proved. But this method has some problems on the aspect of construction and economy. In order to solve these problems, Cathodic Protection Method by using high durable metal spray was developed. First, the specimen was covered with anodic materials (Zn, Al) by using metal spray. And a performance of corrosion protection was confirmed by measuring corrosion current of specimen. Through the result of experiment, it is possible to know that Cathodic Protection Method by using high metal spray is good to protect to corrosion on reinforced concrete structures.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.2A
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• pp.183-190
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• 2008

The balanced Tx diversity with same data on two antennas can have better or lower performance than STBC Tx diversity, depending on the difference between each phase of two channels when the received signal is processed with MRRC. Therefore, using the feedback information based on the phase estimation in each channels, the better scheme of the balanced Tx diversity and STBC Tx diversity can be selected. However, when the phase condition changes during the transmission as the selected Tx. diversity scheme, the decoded bit can be erroneous because the previously estimated phase and newly estimated phase is different. In this case, the receiver should request the re-transmission of the just received signal to the transmitter part. Through computer simulation, it is shown that the combined scheme of the balanced Tx diversity and STBC Tx. diversity has better performance than STBC Tx diversity.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.17 no.3
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• pp.55-61
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• 2017

In DVB-S3 standard of satellite broadcasting systems, FTN technique is applied to LDPC codes with (1+7) PSK modulation. In standard, BICM-ID and BCJR decoding method are considered to alleviate performance degradation due to FTN processing. BICM-ID method improves performance by calculating a new LLR from hard-decision value of decoder output. BCJR also improves performance by calculating forward and backward matrix each other. However these two methods require high computational complexity. Therefore this paper proposed modified decoding method in order to reduce computational complexity without performance degradation.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.42 no.6
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• pp.522-528
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• 2014

A UHF/VHF full-duplex communication using monopole and dipole antenna has been widely used for cube satellite applications. This kind of communication system requires a dedicated structure panel for antenna integration, which is the one of the disadvantages of the conventional communication system from the accommodation point of view considering the extremely limited volume of the cube satellite. In this study, to maximize the accommodation efficiency of the cube satellite, the commercial UHF half-duplex antenna combined with buck converter for communication modes transition has been considered in the communication system design. Its effectiveness has been verified through link budget analysis based on the antenna specifications and satellite's operation conditions. In addition, the antenna deployment mechanism for the synchronous release of multi-antennas has also been introduced.

• Journal of the Korea Convergence Society
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• v.6 no.2
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• pp.57-64
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• 2015

Inductive Power Transfer (IPT) systems have successfully been developed and used to replace traditional conductive power transfer systems where physical connection is either inconvenient or impossible, such as biomedical implants, undersea vehicles, and contactless battery chargers of robots, for providing power to movable or detachable loads. Inductive Coupling uses magnetic fields to transfer power. There is a primary coil, which generates a magnetic field. Then there is another secondary coil which is composed of a capacitor and a coil, the capacitor creates a circuit with the primary and secondary coils. This paper discusses design method and several implementation alternatives for wireless energy transmission systems. It presents realization examples for these alternatives. Wireless energy transmission is investigated in numerous convergence applications due to its simplicity and advantages.