Parallel Finite Element Analysis System Based on Domain Decomposition Method Bridges

이준성,염곡 강이,이은철,이양창,Lee, Joon-Seong,Shioya, Ryuji,Lee, Eun-Chul,Lee, Yang-Chang Computational Structural Engineering Institute of 2009 한국전산구조공학회논문집 Vol.22 No.1

본 논문에서는 대규모 3차원 구조해석에 필요한 병렬 유한요소해석을 위한 영역분할법의 적용에 대해 묘사하였다. 영역분할법을 사용한 병렬 유한요소법 시스템을 개발하였다. 절점 생성시, 절점들간의 거리가 특정절점에서의 공간함수와 같아지면 절점이 생성되어 진다. 이 절점공간함수는 퍼지지식처리에 의해 조절되어 진다. 기본적인 요소생성은 데로우니 삼각화 기법을 적용하였다. 자동요소생성 시스템을 이용한 영역분할법은 3차원 해석에 큰 도움이 된다. 공간함수와 유사하게 절점들간의 유한요소해석을 위한 병렬 수치 알고리즘으로서 영역분할법을 전체의 해석영역을 완전히 여러 개의 작은 영역으로 겹치지 않게 나누는 공역구배인 반복적 솔버와 결합시켰다. 개발된 시스템의 효용성에 대한 성능을 몇 가지 예를 통해 제시하였다. This paper describes an application of domain decomposition method for parallel finite element analysis which is required to large scale 3D structural analysis. A parallel finite element method system which adopts a domain decomposition method is developed. Node is generated if its distance from existing node points is similar to the node spacing function at the point. The node spacing function is well controlled by the fuzzy knowledge processing. The Delaunay triangulation method is introduced as a basic tool for element generation. Domain decomposition method using automatic mesh generation system holds great benefits for 3D analyses. Aa parallel numerical algorithm for the finite element analyses, domain decomposition method was combined with an iterative solver, i.e. the conjugate gradient(CG) method where a whole analysis domain is fictitiously divided into a number of subdomains without overlapping. Practical performance of the present system are demonstrated through several examples.

결정질 실리콘 태양전지용 실리콘 기판의 표면 미세구조에 따른 곡강도 특성

이준성,권순우,박하영,김영도,김형준,임희진,윤세왕,김동환,Lee, Joon-Sung,Kwon, Soon-Woo,Park, Ha-Young,Kim, Young-Do,Kim, Hyeong-Jun,Lim, Hee-Jin,Yoon, Se-Wang,Kim, Dong-Hwan 한국재료학회 2009 한국재료학회지 Vol.19 No.1

The influence of various surface morphologies on the mechanical strength of silicon substrates was investigated in this study. The yield for the solar cell industry is mainly related to the fracturing of silicon wafers during the manufacturing process. The flexural strengths of silicon substrates were influenced by the density of the pyramids as well as by the size and the rounded surface of the pyramids. To characterize and optimize the relevant texturing process in terms of mechanical stability and the fabrication yield, the mechanical properties of textured silicon substrates were investigated to optimize the size and morphology of random pyramids. Several types of silicon substrates were studied, including the planar type, a textured surface with large and small pyramids, and a textured surface with rounded pyramids. The surface morphology and a cross-section of the as-textured and fractured silicon substrates were investigated by scanning electron microscopy.

화학적 기상 반응에 의한 탄화규소 피복 흑연의 시뮬레이션(Ⅰ)

이준성,최성철,Lee, Joon-Sung,Choi, Sung-Churl 한국세라믹학회 2001 한국세라믹학회지 Vol.38 No.9

2차원적 몬테 칼로 시뮬레이션을 사용하여, 화학적 기상 반응법에 의한 탄화규소 전환층의 생성에 미치는 온도의 영향을 조사하였다. 화학적 기상 반응법은 실리카의 열탄화 환원법에 근거하며, 흑연 기판의 탄소와 실리카 반응기체와의 화학적 반응에 의하여 탄화규소 전환층을 형성하는 방법이다. 탄화규소는 반응기체의 확산 및 반응과 같은 열적활성화 과정을 통하여 생성되기 때문에 탄화규소 전환층의 형성은 온도에 크게 의존함을 알 수 있다. 본 연구에서는 몬테 칼로법을 사용하여 삼각격자로 배열된 2차원적인 계에서 흑연 기판의 미세 기공을 따라 확산된 반응기체와 탄소와의 반응에 의해서 탄화규소가 형성되는 과정을 시뮬레이션을 행하였다. 반응 온도를 1900K, 2000K, 2100K, 2200K로 조건을 달리하여 시뮬레이션 하였으며, 그 계산 결과를 실험 결과와 비교하여 재현성을 검토하고 탄화규소 전환층의 두께와 화학적 조성 구배에 대한 반응 온도의 영향을 검증하기 위한 것이다. A two-dimensional Monte Carlo simulation has been used to investigate the effect of the reaction temperature on the formation of the silicon carbide conversion layer near the surface of graphite substrate The carbothermal reduction of silica is the reaction mechanism of silicon carbide formation on graphite substrate by chemical vapor reaction methods. The chemical composition of silicon carbide conversion layer gradually changes from carbon to silicon carbide because gaseous reactants diffuse through micropores within graphite substrate and react with carbon at the surface of inner pores. The simulation was carried out under the condition of reaction temperature at 1900K, 2000K, 2100K and 2200K for 500MCS. It was found from the results of simulation that the thickness of silicon carbide conversion layer increases with reaction temperature.

몬테카를로 시뮬레이션을 이용한 확률론적 파괴역학 수법의 적용성 검토

이준성(Joon-Seong Lee),곽상록(Sang-Log Kwak),김영진(Young-Jin Kim) Korean Society for Precision Engineering 2001 한국정밀공학회지 Vol.18 No.10

경피용 BCG 접종후 시간경과에 따른 결핵반응 양전률의 비교

이준성(Joon Sung Lee),황경태(Kyung Tai Whang),조성훈(Sung Hoon Cho),전민철(Min Cheol Jeon),김영훈(Young Hoon Kim) 대한소아알레르기호흡기학회(구 대한소아알레르기 및 호흡기학회) 1998 소아알레르기 및 호흡기학회지 Vol.8 No.2

N/A Purpose: During the childhood, Mantoux test is very popular for detecting tuberculous infection and also useful for evaluating the immunity against tuberculosis after BCG vaccination. But, the response and conversion rate are affected by the age of vaccination, the quality of vaccine, the duration after vaccination, and the frequency of the test. Because of local side effect and technical problem of intradermal BCG vaccination, percutaneous multipuncture technique of BCG vaccination was recently introduced and used. However, there has been a study on the conversion rate and side effect only at 3 month after multipuncture BCG vaccination. This study was to evaluate of the differences of the Mantoux reactions and conversion rates according to the duration(3 month, 9 month, and 15 month) after vaccination, gestational age, sex, and feeding type. Methods: 174 neonates(155 of full term infants, 19 of preterm infants) who were born at the Kangnam St. Mary’s Hospital were given multipuneture BCG vaccination within 4weeks after birth between July, 1995 and June 1997. All subjects took Mantoux test using 5TU PPD{NIH, Korea) at 3 month, 9 month and 15 month. BCG injections and interpretation the result of the Mantoux test was done by the same person. Results: 1) The positive rates of Mantoux test which was done at 3 month, 9 month and 15 month after vaccination, were 38.7%, 58.1%, 71.6% in the full term infant group and 31.6%, 31.6%, 47.4% in the preterm infant group, respectively. 2) The size of induration in Mantoux test, which was done at 3 month, 9 month and 15 month after vaccination were 7.3 mm, 9.4 mm, and 10.6 mm in the full term infant group and 5.6 mm, 7.7 mm, 9.2 mm in the preterm infant group, respectively. The size of induration was significantly lower in the preterm infant group as compared with that of the full term infant group 9 month after vaccination. 3) The positive conversion rate, from less than 5 mm to more than 10 mm, was 6.3%(3 infants out of 48 infants who were negative Mantoux test at 3 month became positive at 9 month) and 26.3%(5 infants out of 19 infants who were negative at 9 month became positive at 15 month) in the full term infant group, and 33.3%(one infant out of 5 infants who were negative at 9 month became positive at 15 month). 4) There is no difference in conversion rate of Mantoux test according to the sex and feeding type in both groups 5) Complication rate for multipuncture was 3.2%, which was led by local ulceration and fever in the full term infant group, and 5.3%, which is only fever in the preterm infant group. Conclusion: This results indicate that the size of induration and conversion rate is increased with the duration after vaccination, and the smaller size in the preterm group at 9 month after vaccination maybe due to immunological immaturity of preterm group,

기관지세척액 태아성암항원(Carcinoembryonic Antigen)의 진단적 가치에 대한 연구

이준성 ( Joon Seong Lee ),안상용 ( Sang Yong Ahn ),나우균 ( Uh Kyun Na ),이승원 ( Seung Won Lee ),정연태 ( Yeon Tae Chung ),박춘식 ( Chun Sik Park ) 대한결핵 및 호흡기학회 1987 Tuberculosis and Respiratory Diseases Vol.34 No.3

중합효소 연쇄반응법 ( Polymerase Chain Reaction ) 을 이용한 Helicobacter pylori 의 검출

이준성(Joon Seong Lee),송동화(Dong Wha Song),박찬욱(Chan Wook Park),이문성(Moon Sung Lee),조성원(Sung Won Cho),심찬섭(Chan Sup Shim),진소영(So Young Jin) 대한내과학회 1995 대한내과학회지 Vol.49 No.3

N/A Objectives: Helicobacter pylri (H. pylori) infection is now known to be the major cause of chronic gastritis, and is strongly associated with peptic ulcer disease and gastric cancer. But no unanimity exists among investigators about which method represents an appropriate gold standard for diagnosing H. pylori infection. Polymerase chain reaction(PCR) has great potential for improving the ability to diagnose infectious diseases caused by fastidious or slow growing bacterias. But its clinical usefulness as a diagnostic tool for H. pylori is uncertain. Methods: We performed endoscopic biopsy of stomach (>3 pieces, at antrum) for the rapid urease test (CLO stain) and PCR in 11 patients with duodenal ulcer, 2 patients with gastric ulcer, 3 patients with combined gastric and duodenal ulcer, 2 patients with gastric cancer, and 12 patients with gastritis. In preliminary study, endoscopic instruments were tested for residual H. pylori using PCR after combined manual and machine-cleaning and ultrasonic washing with disinfection in 5 patients with positive CLO test. Gastric biopsy tissues were digested in proteinase K(F.C.: 500pl/ml) for DNA extraction, and PCR amplification was performed by using 20 base oligonucleotide primers(CAM 2, CAM 4) homologous to a portion of the 1.9-kb fragment. PCR assay amplified a 203 bp product which was analyzed by agarose gel electrophoresis. Results: 1) in preliminary study, H. pylori were detected by PCR in 4 postendoscopic samples of working channels and biopsy forceps of 2 patients, and 1 preendoscopic sample of biopsy forceps, 2) Of the 30 patients, 19(63.3%) were positive for H. pylori by PCR, 17(56.7%) were positive by CLO test and silver staining. 3) The grade of severity of gastritis on H-E stain was well correlated with the grade of H. pylori infection on Warthin-Starrry silver stain(r=0.651, p<0.01). 4) Discordant results between PCR & other diagnostic tools were 3 cases. Repeat PCR tests disclosed the same results. Conclusion: PCR test of H. pylori is the most sensitive and reproducible test and can overcome the disadvantages of other diagnostic techniques showing less sensitivity and specificity, but it must be dealt with caution of instrumental contamination.

3차원 균열을 갖는 구조물에 대한 건전성 평가(I)

이준성(Lee, Joon-Seong) 한국산학기술학회 2012 한국산학기술학회논문지 Vol.13 No.8

3차원 유한요소법은 구조물에 존재하는 표면균열과 내재균열들의 응력확대계수를 구하는데 이용되어 진다. 기하모델, 즉 솔리드모델은 3차원 균열들을 포함하고 있다. 국부적인 절점밀도가 선택되어 지면 자동적으로 기하모델 영역에 중첩되어 지며 절점은 버블패깅 방법에 의해 생성되어지고 10절점 사변형 솔리드요소는 데라우니 삼각화 기 술에 의해 생성하였다. 시스템의 정확도와 효용성을 체크하기 위해 인장하중을 받는 평판에 하나의 균열이 존재하는 경우의 응력확대계수를 구해 Raju-Newnam식과 비교하여 5%이내의 차이를 보였다. 또한, 인장하중을 받는 평판에 두 개 균열이 존재하는 경우의 해석을 통해 상호 간섭 효과를 분석하였다. Three Dimensional finite element method (FEM) was used to obtain the stress intensity factor for subsurface cracks and surface cracks existing in inhomogeneous materials. A geometry model, i.e. a solid containing one or several 3D cracks is defined. Several distributions of local node density are chosen, and then automatically superposed on one another over the geometry model. Nodes are generated by the bubble packing, and ten-noded quadratic tetrahedral solid elements are generated by the Delaunay triangulation techniques. To examine accuracy and efficiency of the present system, the stress intensity factor for a semi-elliptical surface crack in a plate subjected to uniform tension is calculated, and compared with Raju-Newman’s solutions. Then the system is applied to analyze interaction effects of two dissimilar semi-elliptical cracks in a plate subjected to uniform tension.

총류탄 기반 침투형 Smart Grenade Robot 개발

이준성(Joon Seong Rhee),박민수(Min Su Park) 제어로봇시스템학회 2012 제어로봇시스템학회 합동학술대회 논문집 Vol.2012 No.7

In this paper, We designed a Rifle Grenade Launched Smart Grenade Robot for surveillance, reconnaissance and precision attack in urban buildings, bunkers, tunnels and caves. We present an effective man-transportable robot system for military operations which is composed of a mobile platform, explosion device, rifle grenade and OCU(Operating Control Unit). The mobile platform equipped with a MCU(Micro Control Unit), low light CCD camera and 2-wheel driving mechanism for driving mechanism. The explosion device has two types for attacking and disabling enemies. For attacking uses high explosive shell and for disabling enemies uses CS Gas. Rifle Grenade is used for launching the robot to a far distance and for protecting the robot from the shock. And the OCU is designed to control and monitor the robot remotely. A military operator can set up the robot system and can control and monitor the robot through OCU. An important point in this Rifle Grenade Launched Smart Grenade Robot design is to design a lightweight robot system which weighs less than 1.5kg for launching, and mounting a small explosion device in the mobile platform.

세기관지염 환아에서 혈청 Tryptase 및 요 N - methylhistamine 치의 역할

이준성(Joon Sung Lee),천선아(Sun Ah Chun),조성훈(Sung Hoon Cho) 대한소아알레르기호흡기학회(구 대한소아알레르기 및 호흡기학회) 1994 소아알레르기 및 호흡기학회지 Vol.4 No.2

N/A Bronchiolitis and bronchopneumonia are common lower airway diseases usually caused by respiratory viral infection in infancy. Especially, bronchiolitis may be the initial manifestation of asthma in many infants. These two disorders have mutual clinical manifestation and pathophysiology. To evaluate the involvement of histamine and mast cell in clinical feature and pathophysiology of bronchiolitis during infancy, we measured serum tryptase as mast cell activation marker and urinary N-methylhistamine levels in 20 patients with broncholitis, bronchopneumonia respectively and 20 normal infants. The results were as follows: 1. There were no significant difference in sreum tryptase levels among bronchiolitis, bronchopneumonia and normal infants. 2. Urinary N-methylhistamine levels in infants with bronchiolitis were significantly raised than those in normal infants (<0.001) and than those in bronchopneumonia infants (<0.01). 3. Serum IgE levels in infants with bronchiolitis were significantly raised than those in infants with bronchopneumonia and normal infants (<0.01), but those in infants with bronchopneumonia were not significantly raised than those in normal infants. 4. In bronchiolits, there was significant negative correlation between urinary N-methylhistamine levels and Pa02 (r= -0.52, p=0.021), but there was no significant correlation in bronchopneumonia(r= -0.40, p=0.081). 5. In bronchiolitis, there was siginifant correlation between urinary N-methylhistamine levels and serum IgE levels (r= 0.55, p=0.012). These results suggest that histamine contributes to the pathogenesis of bronchiolitis in infancy. But it did not come from mast cells and the cellular source of histamine could not be established in bronchiolitis. Elevation serum IgE levels influences on the increment of histamine release, which partially causes hypoxia in bronchiolitis,