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서정식,우종명,Seo Jeong-Sik,Woo Jong-Myung 한국전자파학회 2004 한국전자파학회논문지 Vol.15 No.10
본 논문에서는 보다 소형화된 마이크로스트립 패치 안테나를 제작하기 위해 패치 밑면과 접지면 상에 Iris를 수직으로 부착한 3차원 구조의 마이크로스트립 안테나를 설계$\cdot$제작하였다. 부착된 Iris에 의해 패치 밑면에 흐르는 전류의 경로 증가 및 패치 내부의 유전율이 증가되는 효과를 얻고자 하였으며, 제작결과 중심주파수 1.575 GHz에서 높이 9 mm의 평면형 마이크로스트립 패치 안테나(패치 길이 81.5 mm$\times$패치 폭 90 mm)와 비교하여, 지그재그형으로 Iris를 부착한 경우 최대 $79.1\%$(17 mm$\times$90 mm)의 안테나 길이 단축 효과가 나타났다. 이때 측정된 이득 -1.15 dBd, -10 dB 대역폭 $6.2\%$(98 MHz), E-면 HPBW $154^{\circ}$를 나타내어 본 논문에서 제안된 Iris 를 부착한 마이크로스트립 안테나가 소형화에 유효함을 확인하였다. In this paper, the 3-dimensional microstrip antenna, where the lis is attached near the patch, on the pound and both patch and ground in zigzag, is designed and fabricated to miniaturize size of antenna. The path of surface current and permittivity in patch are increased because of attached Iris near the patch, on the pound and patch and found. In particula., the maximum size reduction effect among the three-type of $79.1\%$(17 mm$\times$90 mm) was presented in zigzag-type compared with the rectangular microstrip patch antenna(MPA) with a height of 9 mm at the resonant frequency of 1.575 GHz. The gain showed -1.15 dBd, -10 dB bandwidth showed 6.2$\%$(98 MHz), and HPBW of E-plane showed $154^{\circ}$. As that result we could confirm that the 3-dimensional structure with attached Irises is the proper form for the miniaturization of microstrip antenna.
평판 도파로에서의 체렌코프 펌프 형태에 의한 광 매개증폭
서정식,Suh, Zung-Shik 한국광학회 2014 한국광학회지 Vol.25 No.1
We have analyzed the amplification of a signal wave in the optical parametric interactions of the pump, signal, and idler waves in planar waveguides, with the pump wave being Cerenkov radiation. Based on the coupled-mode theory, we have derived the first-order coupled-mode differential equations for no pump depletion. The equations can easily be solved numerically. The approximate analytical and numerical solutions of the equations show that the signal wave can be amplified parametrically. 평판 도파로에서 pump가 체렌코프 복사(Cerenkov radiation)의 파동인 경우, pump, signal, 그리고 idler 사이의 매개적 상호작용에 의한 signal의 증폭현상을 해석하였다. 결합모드 이론을 사용하여 pump의 고갈(depletion)을 무시할 수 있는 경우, 수치적 계산으로 쉽게 풀 수 있는 1차 결합모드 미분방정식을 유도하였다. 이 미분방정식의 근사해와 수치적 계산 예를 통해서 signal이 매개적으로 증폭될 수 있음을 보였다.
신경망 분석을 활용한 하수처리장 데이터 분석 기법 연구
서정식,김태욱,이해각,윤종호 한국환경과학회 2022 한국환경과학회지 Vol.31 No.7
With the introduction of the tele-monitoring system (TMS) in South Korea, monitoring of the concentration of pollutants discharged from nationwide water quality TMS attachments is possible. In addition, the Ministry of Environment is implementing a smart sewage system program that combines ICT technology with wastewater treatment plants. Thus, many institutions are adopting the automatic operation technique which uses process operation factors and TMS data of sewage treatment plants. As a part of the preliminary study, a multilayer perceptron (MLP) analysis method was applied to TMS data to identify predictability degree. TMS data were designated as independent variables, and each pollutant was considered as an independent variables. To verify the validity of the prediction, root mean square error analysis was conducted. TMS data from two public sewage treatment plants in Chungnam were used. The values of RMSE in SS, T-N, and COD predictions (excluding T-P) in treatment plant A showed an error range of 10%, and in the case of treatment plant B, all items showed an error exceeding 20%. If the total amount of data used MLP analysis increases, the predictability of MLP analysis is expected to increase further.
徐挺植 영남이공대학 산업기술연구소 1988 産業技術硏究 Vol.2 No.-
This study was carried out to investigate the weight loss and the NaCl gain of chinese cabbage samples during pickling in brine under different conditions including various salinities, brine temperature and leaf shape with relation to kimchi making. When the whole leaves of chinese cabbage samples were used for pickling, their weight loss ratio and NaCl gain increased significantly through all the period of pickling as brine salinity did. Drastic dehydration of pickled leaves occurred especially within 2 hours after brining, thereafter their rate of dehydration decreased greatly and their weight loss ratios in brine salinity 2, 5, 10, 15, 20% were 5.72, 14.81, 15.61, 17.34, 24.10% respectively 12 hours after brining. NaCl gain in pickled cabbage samples was increased greatly in the early stage of brining but it had the tendency to increase still thereafter. The content of NaCl of all the samples pickled at brine salinity 2, 5, 10% did, not reach 3% even 12 hours after brining while that of samples pickled at brine salinity 15,20% reached 3% in the brining time, 6. 7, 3. 8 hours respectively. As the temperature of brine rose, dehydration of pickled cabbage samples did not increase except at the early stage of brining but their NaCl gain increased significantly. In case of pickling of sliced leaves, weight loss ratio increased greatly, reaching twice as much as that of whole leaves at the same brining conditions 12 hours after brining but NaCl gain had no significant difference between them. On the other hand, it was shown that the very high correlations between NaCl gain and weight loss ratio in chinese cabbage samples pickled by the same brining conditions existed.