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김동준,정종문,김정현,황하청,정재윤,조윤희,임현교,구제환,최은하,조광섭,Jin, D.J.,Jeong, J.M.,Kim, J.H.,Hwang, H.C.,Chung, J.Y.,Cho, Y.H.,Lim, H.K.,Koo, J.H.,Choi, E.H.,Cho, G.S. 한국진공학회 2010 Applied Science and Convergence Technology Vol.19 No.1
관경이 수 mm인 세관 램프 내부에서 플라즈마의 확산을 조사하기 위하여 이극성(ambipolar) 확산방정식을 해하였다. 반경 방향의 확산에 의한 유리관 벽에서의 플라즈마 소멸 특성시간은 $\tau_r\;=\;(r_0/2.4)^2/D_a$로 주어진다. 반경 $r_0{\sim}1\;mm$이고 이극성 확산계수 $D_a{\sim}0.01\;m^2/s$ 이면, $\tau_r{\sim}17\;{\mu}s$이다. 이는 램프의 교류전원 구동에서 플라즈마를 유지하기 위한 구동 최소 주파수 ~30 kHz에 해당한다. 고전압이 인가되는 전극부에 발생한 고밀도의 플라즈마가 양광주로 확산되는 특성시간은 $\tau_z{\sim}0.1\;s$이다. 고밀도 플라즈마 경계에서의 시간에 대한 확산속도는 $t{\sim}10^{-6}\;s$일 때 $u_D{\sim}10^2\;m/s$이고, $t{\sim}10^{-3}\;s$이면 그 속도는 $u_D{\sim}1\;m/s$로 느려진다. 따라서 램프 길이 ~1 m에 대하여 전극부에서 생성된 고밀도 플라즈마가 양광주 전체로 확산되는 시간은 수 초가 걸린다. The ambipolar diffusion equation has been solved in a fine-tube lamp of a few mm in diameter. In the diffusion of radial direction, the plasma diffuses and vanishes away at the glass wall by recombination with the characteristic time of plasma loss is given by $\tau_r\;=\;(r_0/2.4)^2/D_a$. With the radius $r_0{\sim}1\;mm$ and the ambipolar diffusion coefficient $D_a{\sim}0.01\;m^2/s$, the vanishing time is calculated $\tau_r{\sim}10\;{\mu}s$ which corresponds to the least value of frequency 30 kHz for the sustaining the plasma in the operation of high voltage AC-power. In the diffusion of longitudinal z-direction, a high density plasma generated at the area of a high voltage electrode, diffuses into the positive column with the characteristic time $\tau_z{\sim}0.1\;s$. The plasma diffusion velocity at the boundary of high density plasma is $u_D{\sim}10^2\;m/s$ at the time $t{\sim}10^{-6}$ s and the diffusion velocity becomes slow as $u_D{\sim}1\;m/s$ at $t{\sim}10^{-3}\;s$. Therefore, for the long lamp of 1 m, it takes about several seconds for the high density plasma at the area of electrode to diffuse through the whole positive column space.
증례 : 아메바성대장염에 유발된 다발성 관절염의 1 치험례
김동준 ( D. J. Kim ),조승환 ( S. H. Cho ),김홍수 ( H. S. Kim ),서주영 ( C. Y. Suh ) 대한내과학회 1968 대한내과학회지 Vol.11 No.4
1. A case of polyarthritis secondary to amebic colitis is reported, and this is considered to be a first case in Korea. 2. The diagnosis of amebic colitis was established by the isolation of the ameba from the stool and the subsequent rapid response of the
김동준(D.J. Kim),이종주(J.J. Lee),문영환(Y.H. Moon) 대한전기학회 2010 대한전기학회 학술대회 논문집 Vol.2010 No.11
This paper describes the dynamic modeling of Doubly-Fed Asychronous generator (DFAG) including both rotor and PLL dynamics for transient stability study in power systems. The suggested DFAG machine model uses the stator field orientation reference frame and Per Unit generator parameters. This suggested DFAG model is verified by running both the steady state conditions and rotor current step dynamic test using 6-machine and 23-bus system.
김동준(D.C.KIM),김태형(T.H.KIM),김종원(J.W.KIM),김정훈(J.H.KIM),이강묵(K.M.LEE) 한국자동차공학회 1998 한국자동차공학회 춘 추계 학술대회 논문집 Vol.1998 No.11_2
Today's metal-forming industry is looking for fast, effective and reliable techniques for product designs. If required final products are not known, trial and error techniques are often utilized for manufacturing products. However, these techniques are not adequate for current increasingly competitive markets, where rapid product developments are needed for staying in business. For this reason, lots of leading metal-forming industries are taking advantage of the Computer Aided Engineering(CAE) for their product and process designs. Through the CAE application in product developments, thousands of hours required for trial and error can be eliminated for metal-forming industries depending on empirical rules and intuition of engineers. The CAE plays an important role in reducing cost and development time of a product and achieving high quality products in a competitive market. However, lots of domestic metal-forming industries are not concerned about the application of CAE for their products, even if the CAE for metal-forming simulation is very popular in the U.S. and Europe at the present time. In this paper, an attempt is made to highlight the importance and application of CAE in forging and casting processes by means of specific examples that have been successfully performed at Samsung Electro-Mechanics Co.<br/>
SSD 방법을 이용한 Cut transition 검출 모델
박성민(Sungmin Park),윤의녕(Ui Nyoung Yoon),조근식(Geun-Sik Jo) 한국정보과학회 2020 정보과학회논문지 Vol.47 No.7
샷 경계 검출은 영상 콘텐츠 분석을 위한 필수적인 기술로 꾸준히 연구되고 있다. 본 논문에서는 기존 연구의 단점을 보완하고 Cut transition의 정확한 위치를 찾아내기 위해 SSD(Single Shot Multibox Detector) 방법을 이용한 종단간학습(End-to-End Learning) 모델을 제안한다. 여러 개의 Cut transition을 예측하기 위해 SSD의 다중 스케일 특징 맵(Multi-Scale Feature Map)과 Default box 개념을 적용하였으며, Cut transition의 특징 정보를 강화하기 위해 이미지 비교 방법 중 하나인 Image Concatenation 개념을 모델에 결합하였다. 제안하는 모델은 최신 연구와 비교하여 다시 레이블링을 한 ClipShots 데이터셋과 TRECVID 2007 데이터셋에서 각각 88.7%, 98.0%의 정확도를 보였다. 또한 기존의 딥러닝 모델보다 정답에 가까운 범위를 검출할 수 있었다. Shot boundary detection is constantly being studied as an essential technique for analyzing video content. In this paper, we propose an End-to-End Learning model using the SSD (Single Shot Multibox Detector) method to resolve the shortcomings of the existing research and to identify the exact location of the cut transition. We applied the concept of the Multi-Scale Feature Map and Default box of the SSD to predict multiple cut transitions, and combined the concept of Image Concatenation, one of the image comparison methods, with the model to reinforce the feature information of the cut transitions. The proposed model showed 88.7% and 98.0% accuracy in the re-labeled ClipShots and TRECVID 2007 datasets, respectively, compared to the latest research. Additionally, it detected a range closer to the correct answer than the existing deep learning model.