• 전자공학회논문지 IE
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• v.46 no.4
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• pp.25-30
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• 2009

The cooling water circulation pipes had been used to drop the temperature of refractory outside shell of blast furnace by cooling plate or stave type. They were attacked by surrounding CO gas and it was the cause that they were corroded and the water inflow in the refractory due to leakage of water. So, the life of refractory material was shorten and changed for the worse the conditions of blast furnace. The automatic sensing device for water leakage of cooling pipe was developed to check the position of trouble by use the micro-process system when cooling water leak and then CO gas will be inflowed into the cooling pipe at the leakage position. The inflowed CO gas will be detected in the micro-process system and delivered the detected position of cooling plate or stave to main control room through the wireless-radio relay station. This system can be possible to detect the position of cooling plate or stave the water leakage part immediately and then deliver the signal to main control room by use the micro-process system and wireless-radio relay station. This system will develop the working condition from manual system to unmanned auto alarm system.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2017.11a
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• pp.215-217
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• 2017

기술의 발달에 따라 무인표지에도 기존의 등명기 이외에도 Racon, Fog Detector, 전기폰, 기상 및 해양 관측장비, 휴대폰 중계기 등 전력을 필요로하는 다양한 장비가 설치되고 잇는 실정인데 반해, 현재의 무인표지 전력제어시스템은 기존의 관습대로 등대 내 협소한 구내에 축전지, 충방전 조절기, 전력선 등이 널 부러져 있는 상태로서 효과적인 전력관리와 능률적이고도 안전한 전력 관리를 위하여는 종합적 전력제어시스템 설치가 필요한 실정이다.. 이 연구에서는 현재 무인표지의 전력 시스템을 체계적이고도 안전한 방법으로 관리 할 수 있으며, 축전지 잔량표시, 저전압 충전시스템, 낙뢰피해 방지 및 원격 감시기능 등 기능적인 측면에서도 뛰어난 성능을 가질 수 있도록 무인등대용 표준전력제어장치를 연구 개발하였다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.16 no.11
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• pp.1084-1094
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• 1991

Upon introducing satellite communication system to korea, one of the important problems to copy with is the effect from the probable intentional interference i. e. jamming. In this paper, we have considered the M any PSK signal and the soft limiter type, which contains hard limiter, nonhnear satellite transponder in environments of uplink tone or noise jamming plus Gaussian noise and downlink Gaussian noise. Using the derived error rate equation, we have evaluated numerically the error performance of BPSK and QPSK system, and shown in figures in terms of upink and downink earner to jamming rater(CJR) and limiting level. From the results we have known that tone jamming effect on the error performance in BPSK and QPSK signals in nonlinear satelhie shnnel become less with increasing the uplink CNR and with decreasing the liniting level. And in a tone jamming, the limiting level affects hardly on the error performance of both BPSK and QPSK signals. When limiting leveri is zero, BPSK and QPSK signals show the best error rate performance.

• 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.341-350
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• 2007

In this paper, the derivation of protection ratio is newly proposed for the detailed planning of frequency coordination in microwave relay networks, and computed results for protection ratio of co-channel and adjacent channel are illustrated over the actual system and its frequency. It is shown that the suggested method based upon availability prediction can be expressed in terms of composite fade margin, interference-to-noise ratio(I/N), net filter discrimination, and system parameters. According to results, for 6.7 GHz, 60 km, 64-QAM, and I/N= -6 dB at BER $10^{-6}$, composite fade margin and co-channel protection ratio provide 25.5 and 50.7 dB, respectively. Also, net filter discrimination and adjacent channel protection ratio are obtained as 26.3 and 24.4 dB, respectively, at the first adjacent channel of 40 MHz. The proposed method provides some merits in computing protection ratio for microwave relay networks in view of an easy extension and practical applications considering more detailed and various system parameters.

• Journal of Broadcast Engineering
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• v.23 no.2
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• pp.253-260
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• 2018

Personalized media broadcasting services can produce their own broadcasting contents with a variety of creative themes if they have just a transmission platform and devices that can obtain videos and voices of producers without the existing expensive equipment. In this paper, we develop and implement a new broadcasting system by applying this service framework to events such as seminars or academic conferences. The devices can be installed at each conference rooms and the integrated system transmitted to users. They can watch via their multi-resolution screen, such as smart-phones, laptops, and tablet PCs. It has the advantage of being able to receive real-time streaming and VOD services as well as additional information related to the conference. It is expected to provide convenience by allowing attendees to access the information via their devices, thereby creating an impact on participation and the underlying technology for the future research.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.20 no.11
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• pp.1145-1160
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• 2009

In this paper, a dual band microstrip antenna with soft surface for gapfiller applications is proposed. The proposed antenna with similar radiation pattern and gain is fabricated on RO4003 substrate with a dielectric constant of 3.38 and a thickness of 0.508 mm, and operates in IEEE 802.11a/b bands. The size of the antenna is $50{\times}56.5{\times}5.5\;mm^3$ and the ground plane size including soft surface structure is $175.0{\times}154.4\;mm^2$. The antenna is fed by coaxial cable. The simulated bandwidths of the antenna are 2.388~2.493 GHz and 5.561~6.051 GHz for VSWR<2. The gains are 10.63 dBi and 10.33 dBi, respectively, for the lower and upper bands.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.11B
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• pp.1696-1703
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• 2010

Increased demand for military satellite communications system and due to the depletion of resources of existing satellite communications frequencies, Ka-band and EHF-band satellite communication systems is growing demand for development. As a result, the study of rain attenuation mitigation for Ka/EHF-band frequencies has been achieved. The method to compensate rain attenuation on Ka-band(20/30) using the signal power measurement function in Digital Transponder of Next Military Satellite has been proposed in this paper. This method is more effective than generally used method by Beacon and UPC(uplink power control) in giving the precise rain attenuation measurement and correction.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.10A
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• pp.997-1005
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• 2008

In this paper, we propose an efficient space-time block coding (STBC) scheme in a cooperative satellite-terrestrial system. The proposed STBC scheme has code rate 1 for a 3 transmit antenna scheme. Because the channel matrix of the proposed scheme is orthogonal, we can use a simple linear decoding algorithm and also can expect improved performance over the conventional scheme. The simulation results demonstrate that the proposed scheme has improved performance for bit error rates (BER) than several conventional STBC schemes. In addition, we investigate performance simulation results by power imbalance between the terrestrial repeaters and satellite.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2018.06a
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• pp.71-72
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• 2018

학술대회에 발표된 논문은 이동형 저장장치 혹은 학회 홈페이지를 통해 배포된다. 이용자가 저자의 설명 없이 배포된 논문만으로는 내용을 이해하는 데에 한계가 있다. 이러한 한계를 해결하고 더 나아가 언제 어디서든 설명을 들을 수 있는 환경을 제공하기 위해 웹 기반으로 MPEG-DASH 기반의 학술대회 중계용 가상 포스터세션 서비스를 제안한다. 제안하는 서비스는 포스터 발표자의 영상을 가상공간에 배치하고 이를 MPEG-DASH 기반으로 전송한다. 가상공간은 구글의 WebVR API을 응용해 구현하여 별도의 프로그램 설치 없이 웹 기반으로 이용할 수 있으며 MPEG-DASH 기반의 전송을 통해 효율적인 대역폭 활용이 가능하다. 본 서비스를 통해 논문의 내용을 효과적으로 전달할 수 있을 것이며 새로운 학술대회의 패러다임 제시가 가능할 것으로 예상한다.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.46 no.12
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• pp.108-116
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• 2009

In this paper, we propose a Ethernet based audio distribution system with a new L1/L2 hybrid switching scheme, and evaluate its performance. The proposed scheme not only offers guaranteed low latency and jitter characteristics that are essentially required for the distribution of high-quality uncompressed audio traffic, and but also provide an efficient transmission of data traffic on the Ethernet environment. The audio distribution system with a proposed scheme consists of a master node and a number of relay nodes, and all nodes are mutually connected as a daisy-chain topology through up and downlinks. The master node generates an audio frame for each cycle of 125us, and the audio frame has 24 time slotted audio channels for carrying stereo 24 channels of 16-bit PCM sampled audio. On receiving the audio frame from its upstream node via the downlink, each intermediate node inserts its audio traffic to the reserved time slot for itself, then relays again to next node through its physical layer(L1) transmission - repeating. After reaching the end node, the audio frame is loopbacked through the uplink. On repeating through the uplink, each node makes a copy of audio slot that node has to receive, then play the audio. When the audio transmission is completed, each node works as a normal L2 switch, thus data frames are switched during the remaining period. For supporting this L1/L2 hybrid switching capability, we insert a glue logic for parsing and multiplexing audio and data frames at MII(Media Independent Interlace) between the physical and data link layers. The proposed scheme can provide a good delay performance and transmission efficiency than legacy Ethernet based audio distribution systems. For verifying the feasibility of the proposed L1/L2 hybrid switching scheme, we use OMNeT++ as a simulation tool with various parameters. From the simulation results, one can find that the proposed scheme can provides outstanding characteristics in terms of both jitter characteristic for audio traffic and transmission efficiency of data traffics.