http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
여찬일,허영순,박시웅,김거식,강현서,C.I. Yeo,Y.S. Heo,S.W. Park,K.S. Kim,H.S. Kang 한국전자통신연구원 2023 전자통신동향분석 Vol.38 No.2
Space optical communication technology capable of large-capacity, high-speed, and low-latency communication can reduce the size, weight, and power consumption of radio frequency communications in existing satellite systems, thereby reducing launch costs, accommodating additional science instruments, and extending lifetime. Despite the high technical difficulty, various projects are being carried out in advanced countries regarding space technology for use in national security and defense, earth observation, and space communications. We review the advantages, key components, and development trends of space optical communication technology, which is attracting attention in applications such as satellite communications, intersatellite linking, and deep space communications.
Experimental Study on Leak-induced Vibration in Water Pipelines Using Fiber Bragg Grating Sensors
김대길,이아람,박시웅,여찬일,배철호,박형준 한국광학회 2022 Current Optics and Photonics Vol.6 No.2
Leak detection is one of the most important challenges in condition monitoring of water pipelines. Fiber Bragg grating (FBG) sensors offer an attractive technique to detect leak signals. In this paper, leak measurements were conducted on a water distribution pilot plant with a length of 270 m and a diameter of 100 mm. FBG sensors were installed on the pipeline surface and used to detect leak vibration signals. The leak was demonstrated with 1-, 2-, 3-, and 4-mm diameter leak holes in four different pipe types. The frequency response of leak signals was analyzed by fast Fourier transform analysis in real time. In the experiment, the frequency range of leak signals was approximately 340–440 Hz. The frequency shifts of leak signals according to the pipe type and the size of the leak hole were demonstrated at a pressure of 1.8 bar and a flow rate of 25.51 m 3 /h. Results show that frequency shifts detected by FBG sensors can be used to detect leaks in pipelines.
여찬일,허영순,류지형,박시웅,김성창,강현서,이길행,Yeo, C.I.,Heo, Y.S.,Ryu, J.H.,Park, S.W.,Kim, S.C.,Kang, H.S.,Lee, G.H. 한국전자통신연구원 2020 전자통신동향분석 Vol.35 No.2
In recent years, the unmanned aerial vehicle (UAV) assisted mobile free space optical (FSO) communication technique has attracted considerable attention regarding its aims to provide improved communication conditions for fixed-to-fixed FSO network and promising fronthaul and backhaul solutions for 5G+ wireless networks. This can be attributed to its outstanding advantages such as fast deployment and flexible network configuration. The UAV-assisted mobile FSO system can be used to provide cost-effective internet services in rural and remote areas and in hotspot areas that are characterized by increased data traffic. Additionally, it can be used to provide secure communication services under emergency circumstances. In this report, we review recent R&D trends in wireless network technology employing the UAV-assisted mobile FSO technique and key technologies for mobile FSO wireless networks. Furthermore, we introduce drone-based mobile FSO terminals and control systems that we have developed.
광 무선통신 터미널 자동 추적을 위한 영상개선 알고리즘 성능 비교
김거식,허영순,여찬일,박시웅,박형준 한국통신학회 2023 韓國通信學會論文誌 Vol.48 No.7
본 연구에서는 광 무선통신(Optical Wireless Communication, OWC) 시스템에서 터미널 간 자동 광 정렬 및추적 가능한 이미징 시스템을 개발하였으며, 특히, 원거리(1km 이상)에 위치한 터미널 추적 시 화질 저하로 인한검출 성능 한계를 극복하기 위해 다양한 영상개선 알고리즘 적용하고 성능을 비교하였다. 이를 위해 OWC 터미널추적용 타겟 이미지에 대한 학습데이터셋을 구축하고, 전이 학습을 통해 딥러닝 학습모델을 생성하였다. 현장 적용 실험을 통해 수집된 총 40장의 이미지셋에 대해, 영상개선 알고리즘 적용 전 검출 성능(mAP)는 90.0%이었으나, CLAHE(95%), FM(100%), MSR(100%), MSRCR(100%), AMSR(100%), DehazeNet(92.5%) 알고리즘 적용시 타겟 검출 성능 향상 효과를 확인하였다. 그리고, 타겟 검출 성능과 처리 속도를 고려했을 때, OWC 터미널의coarse tracking에는 CLAHE를 적용하는 것이 최적인 것으로 분석되었다.