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백 플레인의 사각형 개구를 관통하는 전송 선로의 근사 해석법
정성우(Sung-Woo Jung),최범진(Beom-Jin Choi),최봉열(Bong-Yeol Choi),김기채(Ki-Chai Kim) 한국전자파학회 2010 한국전자파학회논문지 Vol.21 No.9
본 논문에서는 백 플레인의 개구를 관통하는 대칭 전송 선로 구조를 해석하기 위한 근사 해석법을 제안하고 있다. 제안된 방법은 백 플레인의 개구면 임피던스를 모멘트 법으로 계산하고, 이 값을 전송 선로에 병렬로 연결한 근사 등가 전송 선로를 해석하여 삽입 손실 특성을 계산하는 방법이다. 근사 해석법을 적용하여 계산한 결과, 정합이 되었을 때는 관통하는 전송 선로와 개구가 가까울수록 특정 주파수에서 삽입 손실이 증가하며, 부정합된 경우에는 특정 주파수에서 삽입 이득 현상이 나타나고 있다. 또한, 개구의 가로 길이가 세로 길이보다 전송 선로에 더 큰 영향을 미친다는 것도 확인하고 있다. 근사 해석법의 타당성을 검증하기 위해, 근사 해석법으로 계산된 삽입 손실 특성을 실험치 및 상용툴의 계산 결과와도 비교하였다. This paper presents the approximate analysis method for the symmetric transmission line crossing the aperture in an backplane. The method of moments is used to determine the aperture impedance for the construction of the equivalent transmission line that the aperture impedance apply to the transmission line as the shunt impedance. As the results, the insertion loss increases at the specific frequency range for the impedance matching. In the case of the mismatching, we are confirmed to the insertion gain at the specific frequency. Also the horizontal length of the aperture affects to the transmission line better than vertical length. The measurement of the insertion loss is performed to verify the theoretical analysis.
백 플레인의 개구를 통과하는 길이가 다른 전송 선로의 삽입 손실 특성
정성우(Sung-Woo Jung),김기채(Ki-Chai Kim) 한국전자파학회 2008 한국전자파학회논문지 Vol.19 No.2
본 논문에서는 무한히 넓은 백 플레인의 사각형 개구를 관통하는 길이가 다른 평행 2선 전송 선로에 대하여 백 플레인의 존재가 전송 선로에 미치는 영향을 검토하였다. 이론 해석에는 FDTD법을 사용하였으며, 길이가 다른 구조를 가지게 하는 부가 선로의 길이와 전송 선로의 간격 변화에 따른 반사 손실 및 삽입 손실 특성을 계산하여 백 플레인이 전송 선로에 미치는 영향을 고찰하였다. 그 결과, 전송 선로의 간격이 좁은 경우에는 부하측의 전송 선로가 안테나처럼 동작하여 삽입 이득 특성이 나타나고, 부가 선로의 길이가 길어지면 백 플레인에 의한 삽입 손실 특성이 현저히 나타남을 확인할 수 있었다. 반사 손실을 측정하고 수치 계산 결과와 비교하여 이론 해석의 타당성도 확인하였다. This paper presents the backplane effects for two-wire transmission line with different line length crossing the rectangular aperture in an infinite ground backplane. The FDTD method is used to determine the characteristics of the backplane insertion loss and return loss of the transmission line in accordance with the transmission line spacing and additional wire lengths. The results show that the insertion gain is obtained for the narrow spacing of the transmission line and the insertion loss is appeared for the transmission line with the additional wire. The measurements of return loss are performed to verify the theoretical analysis.
i-FireNet: 에지 AI 환경에서 실시간 산불감지를 위해 일반화 성능을 향상한 경량형 합성곱 신경망
정성우,유준혁 제어·로봇·시스템학회 2020 제어·로봇·시스템학회 논문지 Vol.26 No.9
Early detection of wildfire is critical to reduce the damage caused by delaying fire control within the golden time. A solution for detecting forest fires automatically is a deep-learning-based visual recognition system using autonomous drones. This paper proposes a new lightweight CNN(Convolutional Neural Network) model, called i-FireNet, that achieves increased classification accuracy and generalization performance for real-time detection of forest fire in the embedded computing environments such as drones. To better discern unresolved images of forest fires observed in the existing FireNet, this work presents an improved-FireNet(i-FireNet) CNN architecture by exploiting four novel design techniques, data augmentation, batch normalization, YCbCr pre-processing, and global average pooling. Experimental results show that the proposed i-FireNet increases the classification accuracy by 6.77% compared with the existing FireNet while maintaining its real-time performance in the edge device. Furthermore, the proposed architecture occupies 40% less memory space than the existing one. .
정성우,Anuj Parajuli,유창식,박성호,이종석,김아영,이종률,김찬욱,윤용식,박인자,임석병,김진천 대한대장항문학회 2019 Annals of Coloproctolgy Vol.35 No.5
Purpose: We investigated the sensitivity of various evaluating modalities in predicting a pathologic complete response (pCR) after preoperative chemoradiation therapy (PCRT) for locally advanced rectal cancer (LARC). Methods: From a population of 2,247 LARC patients who underwent PCRT followed by surgery at Asan Medical Center, Seoul, Korea from January 2007 to June 2016, we retrospectively analyzed 313 patients (14.1%) who showed a pCR after surgery. Transrectal ultrasound (TRUS), high-resolution magnetic resonance imaging (MRI), abdominopelvic computed tomography (AP-CT), and endoscopy were performed within 2 weeks prior to surgery. Results: Of the 313 patients analyzed, 256 (81.8%) had a pCR after radical surgery and 57 (18.2%) showed total regression after local excision. Preoperative TRUS, MRI, and AP-CT were performed in 283, 305, and 139 patients, respectively. Among these 3 groups, a prediction of a pCR of the primary tumor was made in 41 (14.5%), 51 (16.7%), and 27 patients (19.4%), respectively, before surgery. A prediction of a clinical N0 stage was made in 204 patients (88.3%) using TRUS, 130 (52.2%) using MRI, and 78 (65.5%) using AP-CT. Of the 211 patients who underwent endoscopy, 87 (41.2%) had a mention of clinical CR in their records. A prediction of a pathologic CR was made for 124 patients (39.6%) through at least one diagnostic modality. Conclusion: The various evaluation methods for predicting a pCR after PCRT show a predictive sensitivity of 0.15–0.41 for primary tumors and 0.52–0.88 for lymph nodes. Endoscopy is a relatively superior modality for predicting the pCR of the primary tumor of LARC patients.