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.

듀얼 에너지 CT의 가상 단색 영상을 이용한 영상 교정 팬텀과 금속 인공음영에 관한 연구

이준성,이승훈,박주경,이선영,김진기,Lee, Jun seong,Lee, Seung hoon,Park, Ju gyung,Lee, Sun young,Kim, Jin ki 대한방사선치료학회 2017 대한방사선치료학회지 Vol.29 No.1

목 적: 이중선원 듀얼에너지 CT(DS-DECT)의 가상 단색 영상을 이용해서 영상의 질 향상과 선량학적 영향에 대한 방사선치료계획 이용의 유용성을 평가하고자 한다. 대상 및 방법: DS-DECT를 이용하여 듀얼에너지(80/Sn 140 kVp)와 싱글에너지(120 kVp) 영상을 획득하였다. 영상 교정 팬텀 실험을 위해서 40-140 keV 범위로 단색 영상을 재구성했다. 선량 측정용 고체물등가팬텀 연구에서는 64, 69, 88, 105 keV 단색 영상을 선택했다. 스테인리스 스틸을 포함한 고체물등가팬텀에 $10{\times}10cm^2$ 조사야, SSD 100 cm, 10 MV 광자선, 100 MU 조사선량, 단일빔으로 치료계획을 수립하였다. 방사선량측면도 자료는 중심축에 위치한 4개의 지점에서 구했다. 싱글에너지 CT에서 획득한 다색 영상을 기준영상으로 하고, 가상 단색 영상의 선량학적 결과를 분석하였다. 결 과: 낮은 단색 에너지 수치에서 평균 감약이 증가했다. 7개의 물질 중에서 Teflon이 에너지 의존성이 가장 컸고, 10 keV 수치 상승으로 CT number가 평균 2.48 % 감소했다. 저밀도 공기에서는 단색 에너지에 대한 에너지 의존성이 없었다. Polystyrene, Acrylic은 70 keV 이상에서 안정한 CT number를 나타내었다. CT-ED 변환 곡선은 80 keV 단색 영상과 120 kVp 다색 영상이 비슷하였다. 단색 영상의 에너지가 증가할수록 금속의 식별 능력이 향상되었다. 줄무늬 인공음영은 105 keV 단색 영상에서 높은 감소를 보였지만, 여전히 남아 있었다. 다색 영상과 비교하여 각 영상에 따른 방사선치료계획의 선량학적 차이는 ${\pm}0.7%$ 미만이었다. 결 론: 듀얼에너지 영상의 획득은 싱글에너지에 비해 피폭선량을 감소시킬 수 있고, 가상 단색 영상은 CT number 보정에 유용하였다. 향상된 영상의 질은 인체의 기하구조 묘사와 전자 밀도 분포 형성에 도움이 될 것으로 사료된다. Purpose: To evaluate the image quality improvement and dosimetric effects on virtual monochromatic images of a Dual Source-Dual Energy CT(DS-DECT) for radiotherapy planning. Materials and Methods: Dual energy(80/Sn 140 kVp) and single energy(120 kVp) scans were obtained with dual source CT scanner. Virtual monochromatic images were reconstructed at 40-140 keV for the catphan phantom study. The solid water-equivalent phantom for dosimetry performs an analytical calculation, which is implemented in TPS, of a 10 MV, $10{\times}10cm^2$ photon beam incident into the solid phantom with the existence of stainless steel. The dose profiles along the central axis at depths were discussed. The dosimetric consequences in computed treatment plans were evaluated based on polychromatic images at 120 kVp. Results: The magnitude of differences was large at lower monochromatic energy levels. The measurements at over 70 keV shows stable HU for polystyrene, acrylic. For CT to ED conversion curve, the shape of the curve at 120 kVp was close to that at 80 keV. 105 keV virtual monochromatic images were more successful than other energies at reducing streak artifacts, which some residual artifacts remained in the corrected image. The dose-calculation variations in radiotherapy treatment planning do not exceed ${\pm}0.7%$. Conclusion: Radiation doses with dual energy CT imaging can be lower than those with single energy CT imaging. The virtual monochromatic images were useful for the revision of CT number, which can be improved for target coverage and electron densities distribution.

數種의 天然物을 이용한 瘙痒症治療에 대한 實驗的 硏究

이준성,서형식,노석선,Lee, Jun-Seong,Seo, Hyeong-Sik,No, Seok-Seon 대한한방안이비인후피부과학회 2001 한방안이비인후피부과학회지 Vol.14 No.1

확률론적 파괴역학을 도입한 CANDU 압력관의 예리한 결함에 대한 건전성평가

이준성,곽상록,김영진,박윤원,Lee, Jun-Seong,Gwak, Sang-Rok,Kim, Yeong-Jin,Park, Yun-Won 대한기계학회 2002 大韓機械學會論文集A Vol.26 No.4

This paper describes a probabilistic fracture mechanics(PFM) analysis based on Monte Carlo(MC) simulation. In the analysis of CANDU pressure tube, the depth and aspect ratio of an initial semi-elliptical surface crack, a fracture toughness value and delayed hydride cracking(DHC) velocity are assumed to be probabilistic variables. As an example, some failure probabilities of piping and CANDU pressure tube are calculated using MC method with the stratified sampling MC technique, taking analysis conditions of normal operations. In the stratified MC simulation, a sampling space of probabilistic variables is divided into a number of small cells. For the verification of analysis results, a comparison study of the PFM analysis using other commercial code is carried out and a good agreement was observed between those results.

건성안 환자에서 쇼그렌증후군의 빈도 및 임상양상

이준성,최원,이신석,윤경철.Jun Sung Lee. MD. Won Choi. MD. Shin Seok Lee. MD. Kyung Chul Yoon. MD. PhD 대한안과학회 2012 대한안과학회지 Vol.53 No.4

Purpose: To investigate the prevalence and clinical aspects of Sjögren syndrome in patients who were diagnosed with dry eye syndrome in Korea. Methods: The medical records of patients who were diagnosed with dry eye syndrome in a dry eye clinic during a 2-year period (March 2008 to March 2010) and were followed up for more than 3 months were reviewed retrospectively. Results: A total of 206 patients were included in the present study. Fifty-eight patients (28%) had Sjögren syndrome and 39 patients (19%) showed primary Sjögren syndrome. Sjögren syndrome patients showed poorer results than non-Sjögren syndrome patients in ocular surface disease index score (OSDI), tear break up time, Schirmer test score, and ocular surface staining score using the Oxford scheme (p < 0.05). Among the patients with primary Sjögren syndrome, 27 patients were SSA (anti-Ro antibodies) or SSB (anti-La antibodies) positive and 12 patients were sero-negative. There were no statistically significant differences in objective or subjective parameters between the sero-positive and sero-negative groups. Conclusions: Sjögren syndrome was observed in 28% of all dry eye patients, in two-thirds of severe dry eye patients. Sjögren syndrome patients showed more severe clinical aspects than dry eye patients with non-Sjögren syndrome. Diagnosing Sjögren syndrome through systemic evaluation is necessary in the patients with severe dry eye. J Korean Ophthalmol Soc 2012;53(4):499-504

L1210과 HL60 암세포에 대한 야생식물의 세포독성 검색

이준성,민병선,배기환,Lee, Jun-Sung,Min, Byung-Sun,Bae, Ki-Hwan 한국생약학회 1996 생약학회지 Vol.27 No.3

For the search of anticancer compounds from natural products, 43 plants were extracted with benzene and methanol, separately, and the extracts were screened for the cytotoxicity against L1210 and HL60 cancer cell lines. From the results, 22 samples in benzene extracts showed cytotoxicity against L1210 cells and 23 samples against HL60 cells, respectively. However, any methanol extracts did not exhibit cytotoxicity against two cancer cell lines, it suggested that cytotoxic compounds seemed to have low polarity. $ED_{50}$ values less than $5\;{\mu}g/ml$ were observed in 14 and 9 samples in benzene extracts against L1210 and HL60 cancer cells, respectively.

齒牙 및 齒周疾患에 使用되는 藥物에 관한 文獻的 考察

이준성,유현신,서형식,노석선,Lee, Jun-Seong,Rheu, Hyun-Sin,Seo, Hyung-Sik,Rho, Seok-Seon 대한한방안이비인후피부과학회 2001 한방안이비인후피부과학회지 Vol.14 No.2

The result were as follows: 1. Apply the drug to the Dental and Paradental digease is used to be very busy on the Gypsum Fibrosum( 石膏) and Asari herba cum Radice(細辛). 2. Apply the drug to the Dental and Paradental digease is clearing away heat and helping sweat 3. Apply the drug to the Dental and Paradental digease is cold and hot. 4. Apply the drug to the Dental and Paradental digease is pungent, bitter and sweet. 5. Apply the drug to the Dental and Paradental digease is non-toxic. 6. Apply the drug to the Dental and Paradental digease is used to be very busy on the chanel of liver and stomach.

산후부종(産後浮腫)에 대(對)한 문헌적(文獻的) 고찰(考察)

이준성,류동열,Lee, Jun-Seong,Ryu, Dong-Yeol 대전대학교 한의학연구소 1995 한의학연구소 논문집 Vol.4 No.1

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.

網膜中心動脈閉鎖 患者 1例에 對한 臨床的 考察

이준성,류현신,서형식,노석선,Lee, Jun-Seong,Ryu, Hyeon-Sin,Seo, Hyeon-Sik,No, Seok-Seon 대한한방안이비인후피부과학회 2001 한방안이비인후피부과학회지 Vol.14 No.2

In the Clinical study on 1 Case of Patient with Obstruction of the retinal artery, the results were as follows. 1. Obstruction of the retinal artery is acute disease that vision isdiminished fastly and become a blindness. 2. It belong to the cathegory of Pock Maeng(暴盲) in Oriental Medicine. 3. The causes of Obstruction of the retinal artery were the yin-deficiency of liver and kidney, the stagnation of vital energy and blood stasis, the abundance of phlegm-heat, the yang-deficiency of spleen and kidney, the yin-deficiency of spleen and kidney, the nonfastness of primordial energy etc. 4. We could get the effective result by providing the patient with Jinkansikpung-tang-gami(鎭肝熄風湯加味) in the acute period 5. In Acupuncture treament and other treament, Electro-acupuncture theraphy ana Lodestone theraphy were useo for neurologic stimulation, Body acupuncture and Auricula-acupuncture were used for promoting the circulation of vital energy and blood.