건식 식각 공정을 위한 초고속 병렬 연산 시뮬레이터 개발

이제희,권오섭,반용찬,원태영,Lee, Jae-Hee,Kwon, Oh-Seob,Ban, Yong-Chan,Won, Tae-Young 대한전자공학회 1999 電子工學會論文誌, D Vol.d36 No.10

This paper report the implementation results of Monte Carlo numerical calculation for ion distributions in plasma dry etching chamber and of the surface evolution simulator using cell removal method for topographical evolution of the surface exposed to etching ion. The energy and angular distributions of ion across the plasma sheath were calculated by MC(Monte Carlo) algorithm. High performance MPP(Massively Parallel Processing) algorithm developed in this paper enables efficient parallel and distributed simulation with an efficiency of more than 95% and speedup of 16 with 16 processors. Parallelization of surface evolution simulator based on cell removal method reduces simulation time dramatically to 15 minutes and increases capability of simulation required enormous memory size of 600Mb. 건식 식각 공정을 시뮬레이션하기 위하여, 플라즈마 챔버 내의 식각 이온 거동 메카니즘을 몬테카를로 수치해석 방식으로 구현하였고, 식각 이온의 거동에 의한 기판의 식각 형상을 확인하기 위하여 셀 방식의 표면 전진기를 개발하였다. 몬테카를로 수치 계산의 단점인 과다한 계산 시간을 효과적으로 감소시키기 위하여, CRAY T3E 병렬 컴퓨터와 여러대의 워크스테이션을 연결한 MPI 환경에서 몬테카를로 병렬 계산 알고리즘을 개발하였다. 본 연구에서 개발한 몬테카를로 병렬 계산 알고리즘은 95% 이상의 효율성을 보이며, 16개의 프로세서를 사용하였을 때 16의 스피드업(Speedup) 값을 얻었다. 또한 셀 방식의 병렬 연산 표면 전진기를 이용하여 토포그래피 시뮬레이션을 수행한 결과에서, 셀의 개수가 2갭만 개 일 때, 약 600Mb 이상의 메모리가 소요되므로 단일 워크스테이션 환경에서는 불가능한 계산이 본 연구에서 개발한 병렬 계산 알고리즘을 이용하였을 때 32개의 프로세서에서 15분의 계산시간이 소요되었다.

대안적 방식의 극영화 제작 워크숍 수업모델에 대한 이론적 고찰

이제희(Lee, Jae Hee) 한국영화학회 2012 영화연구 Vol.0 No.54

‘I was only combining time and space, but from that moment on I was pressed into telling stories,’ explained German director Wim Wenders. An understanding of spatial and temporal setting and its effect on the narrative of a film is essential for the filmmaker. And his or her cinematic vision should be expressed in the form of an image and sound throughout the process of filming. This article examines the components of what should be taught in the context of the frame of a moving image through an introductory fiction film production workshop course. Based on the notion of spatial-temporal and audio-visual aesthetics, it requires consideration from various perspectives of the frame; framing and its meaning, visual structure and composition which are culturally wrought and practised, fundamentals of narration in the frame and image sequencing project employed in visual storytelling. This article covers the basics of a pictorial and dramatic vision through an aesthetic contemplation on the basis of various filmtheories from the tradition of formalism to Deleuze. Ultimately, the goal of this study is to make students be well versed in the theory and practice of narrative film production from both aesthetic and technical perspectives.

석탄 화력발전소의 비산재를 이용한 건식 CO₂ 흡수제 제조 및 특성 연구

이제희(Jae Hee Lee),위정호(Jung Ho Wee) 大韓環境工學會 2013 대한환경공학회지 Vol.35 No.8

본 논문에서는 석탄화력발전소에서 배출되는 비산재의 CO₂ 건식흡수제의 첨가제 및 담체로써의 효과를 검토하였다. 이를 위해 필요에 따라 비산재와 CO₂ 포집 유효 성분인 NaOH, CaO 및 물을 조합하여 여러 종류의 흡수제를 제조한 후, CO₂흡수 실험을 포함한 흡수제의 특성 분석을 수행하였다. 그 결과, 조건에 따라 흡수율과 흡수 온도, 속도 및 탈기 현상 등, 비산재 투입에 의한 다양한 효과를 확인할 수 있었고 NaOH, CaO 및 비산재와 물이 첨가되어 제조된 흡수제에서 비산재 효과가 가장 크게 나타났다. 550℃에서 본 흡수제의 CO₂ 흡수율은 비산재가 첨가되지 않은 흡수제에 비해 35.6% 높았고 흡수종료 후, CO₂ 탈기 현상도 관측되었다. 이는 비산재 첨가 때문으로 흡수제 내, 유효 성분들이 비산재 주변으로 분산도가 높고 상대적으로 미세한 입자로 존재하였다. 또한 비산재의 담체 역할이 확인되며 NaOH로 인해 흡수제 내 포졸란 반응이 억제되기 때문이다. 탈기 현상도 비산재 첨가로 인한 현상으로 NaOH, CaO가 비산재와 물리, 화학적 결합을 형성하여 Na와 Ca에 포집되어 있는 CO₂의 결합력이 약화되기 때문으로 판단된다. This paper investigates the effect of coal-fired fly ash on dry CO₂ sorbents as the supports and additives. For this purpose, various kinds of dry sorbent were manufactured by mixing fly-ash, the primary CO₂ absorption components (NaOH and CaO) and water with their different combination. Thereafter, their CO₂ absorption performance and the property were analyzed. As a result, variation of absorption efficiency and temperature as well as CO₂ desorption of the sorbents are confirmed, which may be primarily ascribed to fly-ash addition to the sorbents. Particularly, fly-ash effect is strongly measured in the sorbent manufactured by mixing all four components (named WNCF sorbents). Absorption efficiency of WNCF sorbents at 550℃ is 35.6% higher than that of fly- ash free sorbent and desorption is solely observed in WNCF sorbents. Fly-ash in WNCF sorbents leads to increase the dispersity of CO₂ absorption components and decrease their particle size in the sorbents. In addition, fly-ash is used as the supports and pozzolanic reaction is hindered by NaOH in WNCF sorbent. Furthermore, CO₂ desorption from the sorbents may be due to fly-ash. The interaction between fly-ash and CO₂ absorption components substantially attenuate the strength between captured CO₂ in CaO and NaOH.

다변량 대량 데이터 내의 소량의 이상 데이터 원인 규명을 위한 학습 및 추론

이제희(Jae-Hee Rhee),이상형(Sang Hyoung Lee) 대한전자공학회 2018 대한전자공학회 학술대회 Vol.2018 No.6

In this paper, we propose a method of learning and reasoning about the factors causing a small amount of abnormal data in multivariate large dataset. Here, the normal and the abnormal data are distributed together in an interval of similar values in the univariate comparison. We propose two probabilistic analysis methods to solve this problem: 1. the ratio analysis of normal/abnormal data in a probability interval and 2. the likelihood analysis of individual univariate factors. These two methods are evaluated by applying them to the existing decision tree mode using the dataset obtained from the acutual automotive parts production process.

인간-로봇 협업을 위한 물리적 상호작용 확률 모델링 기술의 활용 및 평가

이제희(Jae-Hee Rhee),이상형(Sang Hyoung Lee) 대한전자공학회 2018 대한전자공학회 학술대회 Vol.2018 No.6

In human-robot collaboration task, a human and a robot should be able to interact with each other and achieve a common goal. Communication between these two entities is essential to achieve the goal. The physical interaction of human-robot can be used as important information for the communication. In this paper, we propose a method for probabilistic modeling of the physical interaction of human-robot and its evaluation with task-parameterized gaussian mixture model. For this purpose, the robot and the human are involved in the task of transporting objects together.

불균질부 방사선치료 시 계획 선량의 정확성 평가

김찬용,이제희,곽용국,하민용,Kim, Chan Yong,Lee, Jae Hee,Kwak, Yong Kook,Ha, Min Yong 대한방사선치료학회 2013 대한방사선치료학회지 Vol.25 No.2

목 적: 불균질부를 포함하고 있는 치료부위의 치료계획 시 불균질 경계면에서의 TPS상 선량분포와 phantom을 이용하여 측정된 실제 선량분포를 비교하여 그 차이를 알아보고자 한다. 대상 및 방법: 4 cm 두께의 solid water phantom 사이에 폐와 유사한 밀도를 가진 8 cm 두께의 cork (density: 0.23 $g/cm^2$)를 위치시켜 phantom을 제작하여 CT 영상을 획득하였으며, 본원에서 사용하고 있는 Pinnacle 치료계획 시스템의 Collapsed-cone(CC) convolution 선량계산 알고리즘을 이용하여 6/15 MV 광자선으로 치료 계획된 선량분포와 실제 phantom에 EBT2 필름을 삽입해 측정한 선량을 비교 평가하였다. 또한 실제 폐암 환자와 유사한 치료계획을 비교하기 위해 Phantom 내부에 치료하고자 하는 종양부위(target volume)로 가정한 파라핀($3{\times}3{\times}3$ cm)을 Location "A" (일반조직과 떨어져있는 가상의 종양: 섬모델)와 Location "B" (일반조직과 붙어있는 가상의 종양: 반도모델)에 삽입하여 CT scan 후 치료계획을 시행하였다. 선량계획과 동일한 조건으로 Phantom을 set-up 후 Phantom의 paraffin target volume 경계면 A (Ant방향), B (Rt방향), C (Post 방향) point에 필름을 삽입하고 방사선을 조사하여 측정된 선량을 TPS선량과 비교평가 하였다. 결 과: 불균질 phantom을 이용한 계획선량과 측정선량과의 차이는 solid water와 cork 경계면을 제외한 부분에서 선량차이가 크지 않았지만 밀도가 급격히 변화하는 첫 번째 구간과 두 번째 구간에서 -5.4%~-12.6%의 선량감소를 보였다. 또한 paraffin target을 삽입한 실험에서는 Location "A"의 경우 실제 측정선량이 A, B, C point에서 각각 -2.5~-4.7%, -2.3~-2.8%, -4.5~-8.8%의 낮은 선량을 나타냈으며, Location "B"의 경우에도 A, B, C point에서 각각 0.08~5.27%, -3.17~-4.74%, -7.86~-11.56%의 선량 차이를 나타내었다. 결 론: 이번 연구의 결과 불균질부 내에서의 치료계획 시스템의 계획된 선량과 실제 측정된 선량에 오차의 가능성이 확인되었다. 급속도로 발전하고 있는 방사선 치료기술과 그만큼 정밀함을 요하는 치료계획 시 이러한 가능성에 대해 인지하고 선량검증에 대한 여러 방법들을 연구하고 개발하는 것이 치료의 발전과 필수적으로 동반되어야 할 것이며 본원에서도 이번 연구를 통해 치료계획 시 발생할 수 있는 변수에 대해서 더 주의 깊게 판단하고 적용할 수 있을 것으로 사료된다. Purpose: We are to find out the difference of calculated dose of treatment planning system (TPS) and measured dose in case of inhomogeneous organ structure. Materials and Methods: Inhomogeneous phantom is made with solid water phantom and cork plate. CT image of inhomogeneous phantom is acquired. Treatment plan is made with TPS (Pinnacle3 9.2. Royal Philips Electronics, Netherlands) and calculated dose of point of interest is acquired. Treatment plan was delivered in the inhomogeneous phantom by ARTISTE (Siemens AG, Germany) measured dose of each point of interest is obtained with Gafchromic EBT2 film (International Specialty Products, US) in the gap between solid water phantom or cork plate. To simulate lung cancer radiation treatment, artificial tumor target of paraffin is inserted in the cork volume of inhomogeneous phantom. Calculated dose and measured dose are acquired as above. Results: In case of inhomogeneous phantom experiment, dose difference of calculated dose and measured dose is about -8.5% at solid water phantom-cork gap and about -7% lower in measured dose at cork-solid water phantom gap. In case of inhomogeneous phantom inserted paraffin target experiment, dose difference is about 5% lower in measured dose at cork-paraffin gap. There is no significant difference at same material gap in both experiments. Conclusion: Radiation dose at the gap between two organs with different electron density is significantly lower than calculated dose with TPS. Therefore, we must be aware of dose calculation error in TPS and great care is suggested in case of radiation treatment planning on inhomogeneous organ structure.

호흡동조 방사선치료용 팬텀의 제작 및 유용성 평가

이양훈,이제희,유숙현,Lee, Yang-Hoon,Lee, Jae-Hee,Yoo, Suk-Hyun 대한방사선치료학회 2010 대한방사선치료학회지 Vol.22 No.2

Purpose: The purpose of this study is that through production of phantom for respiration gated radiotherapy, assessing appropriacy of exposure dose for the therapy using RPM (Real-time Position Management). Materials and Methods: We located measurement object on the phantom for respiration gated radiotherapy made of 2 linear actuator, acrylic panel, stanchion, iron plate ets. to drive (up, down, front, back). Using 4D CT scan, we analyzed patient's respiration and reproduced the movement by computer. On the phantom, we located a 2D-Array (PTW) and an White water phantom (4.5 cm) and used DMLC (interval 2 cm) in the field size $10{\times}10\;cm$, then exposed 21EX X-ray 100 MU, in the case of phantom was (1) static (2) moving (3) gated using RPM respectively gantry $0^{\circ}$ and $90^{\circ}$ We measured with a 0.125 CC ionization chamber (PTW) on the phantom (7.5 cm) in the same condition. Results: Ionization chamber: There were within 0.3% of error with gating respiration and approximately 2% of error without gating in the same condition. 2D-Array: Gantry $90^{\circ}$, field size $10{\times}10\;cm$, using DMLC. There were within 3% of error with gating respiration and approximately 16% of error without gating. Conclusion: The phantom for respiration gated radiotherapy makes plans considering patient's movement, quantitative analysis of exposure dose and proper assessment therapy for IMRT patients using RPM possible.

전산화 단층촬영 모의치료기 정도관리 팬텀의 유용성 평가

황세하,민제순,이제희,박흥득,Hwang, Se-Ha,Min, Je-Sun,Lee, Jae-Hee,Park, Heung-Deuk 대한방사선치료학회 2009 대한방사선치료학회지 Vol.21 No.2

Purpose: The purpose is to evaluate efficiency of the CT simulator QA phantom manufactured for daily QA. Materials and Methods: We made holes ($1{\times}100{\times}1\;mm$) to verify accuracy between image and real measurement in polystyrene phantom and made 1 mm holes to verify table movement accuracy at superior and inferior 100 mm to the center of the phantom and inserted radiopacity material. To evaluate laser alignment, we made cross mark on the right and left side at phantom and to evaluate CT number accuracy we made 3 cylindrical holes and inserted equivalence material of bone, water, air in them. After CT scanning the phantom, We evaluated accuracy between image and real measurement, accuracy of table movement, laser, and CT number using exposed image. Results: It was measured that the accuracy between image and real measurement was ${\pm}0.3\;mm$, table movement accuracy was ${\pm}0.3\;mm$, laser accuracy was ${\pm}0.5\;mm$ from 7th January to 7th March in 2008 as within the reference point ${\pm}1\;mm$. In the CT number accuracy of bone was ${\pm}10\;HU$, air was ${\pm}5\;HU$, water was ${\pm}5\;HU$ as within the reference point is ${\pm}10\;HU$. Conclusion: We was able to perform CT simulator QA and laser equipment QA more conveniently and fast using manufactured phantom at the same time. We will be able to make more accurate treatment plan that added to QA procedures using images at previous daily QA.

방사선 치료 시 치료실 내에서 발생하는 오존에 관한 고찰

곽용국,윤일규,이제희,유숙현,Kwak, Yong-Kuk,Yoon, Il-Kyu,Lee, Jae-Hee,Yoo, Suk-Hyun 대한방사선치료학회 2009 대한방사선치료학회지 Vol.21 No.2

Purpose: Measure the ozone level in the treatment room while treating a patient so want to know the degree of contamination caused by ozone occurrence. Materials and Methods: Use the linear accelerator (Clinac 21EX, Varian, USA) with the ozone meter (series-200, aeroQual, New Zealand) and water phantom (Wellhofer, IBA, Germany) is irradiated the radiation so that measured the ozone generation level according to MU, dose-rate, SSD, field size, energy, delay time and put the ozone meter in the treatment room actually while treating a patient so measured the daily ozone level variation. Results: While irradiating the radiation, degree of ozone contamination wasn't affected by the energy but mostly in case of electron beam, ozone level was higher than photon beam. The higher dose-rate (0.016~0.025 ppm/hr), the farther SSD (0.018~0.030 ppm/hr), the wider field sizes (0.016~0.025 ppm/hr), the more MU (0.018~0.046 ppm/hr), it occurred high ozone level. Ozone decrement according to delay time changed the background level (0.016 ppm/hr) after elapsed time of 10 minutes from irradiating radiation. And daily ozone occurrence level in the treatment room was below ozone standard level 0.1 ppm/hr (average:0.06 ppm/8 hr) but it could confirm that ozone generation level was included the level (max:0.038 ppm/hr) above 0.02 ppm/hr which patient could perceive. Conclusion: Through ozone level according to variation of certain conditions, actually in the treatment room ozone generation level didn't damaged to patients or workers. Commonly peoples think that ozone was harmful gas but it thought that small amount of ozone generation level while treating a patient was beneficial in the treatment room through air purge action of pathogenic germ or virus sterilization.

전립선암의 세기조절 방사선치료 시 불균질부에 의한 선량변화에 관한 고찰

윤일규,박장필,이제희,박흥득,Yoon, Il-Kyu,Park, Jang-Pil,Lee, Jae-Hee,Park, Heung-Deuk 대한방사선치료학회 2007 대한방사선치료학회지 Vol.19 No.2

Purpose: The pelvic phantom was fabricated in the following purposes: (1) Dose verification of IMRT plan using Eclipse planning computer, (2) to study the interface effect at the interface between rectal wall and air. The TLD can be inserted in the pelvic phantom to confirm the dose distribution as well as uncertainty at the interface. Materials and Methods: A pelvic phantom with the dimension of 30 cm diameter, 20 cm height and 20 cm thickness was fabricated to investigate the dose at the rectal wall. The phantom was filled with water and has many features like bladder, rectum, and prostate and seminal vesicle (SV). The rectum is made of 3 cm-dimater plastic pipe, and it cab be blocked by using a plug, and film can be inserted around the rectal wall. The phantom was scanned with Philips Brillance scanner and various organs such as prostate, SV, and rectal wall, and bladder wall were delineated. The treatment parameters used in this study are the same as those used in the protocols in the SNUH. TLD chips are inserted to the phantom to evaluate the dose distribution to the rectal wall (to simulate high dose gradient region), bladder wall and SV (to simulate the high dose region) and 2 spots in anterior surface (to simulate the low dose region). The TLD readings are compared with those of the planning computer (ECLIPSE, Varian, USA). Results: The target TLD doses represented as the prostate and SV show excellent agreements with the doses from the RTP within +/-3%. The rectal wall doses measured at the rectal wall are different from the those of the RTP by -11%. This is in literatures called as an interface effect. The underdosages at the rectal wall is independent of 3 heterogeneity correction algorithm in the Eclipse RTP. Also the low dose regions s represented as surface in this study were within +/-1%. Conclusion: The RTP estimate the dosage very accurately withihn +/-3% in the high dose (SV, or prostate) and low dose region (surface). However, the dosage at the rectal wall differed by as much as 11% (In literatures, the underdosage of 9$\sim$15% were reported). This range of errors occurs at the interface, for example, at the interface between lung and chest wall, or vocal cord. This interface effect is very important in clinical situations, for example, to estimate the NTCP (normal tissue complication probability) and to estimate the limitations of the current RTP system. Monte-carlo-based RTP will handle this issue correctly.