SLALOM을 이용한 전광 직렬-병렬 데이터 형식 변환기

이성철,이기철,이석,박진우,Lee, Sung-Chul,Lee, Ki-Chul,Lee, Seok,Park, Jin-Woo 한국광학회 2002 한국광학회지 Vol.13 No.5

In this paper, we propose new simple schemes for all-optical serial-to-parallel and parallel-to-serial data format converters based on a semiconductor laser amplifier in a loop mirror (SLALOM) for all-optical data processing. They have the advantages of simple and easily expandable structure, efficient operation and easy implementation. We implement the proposed all-optical data converters. and experimentally demonstrate their operation. 본 논문에서는 SLALOM(Semiconductor Laser Amplifier in a Loop Mirror)을 사용하여 광신호를 직렬 데이터 형식에서 병렬 데이터 형식으로 또는 병렬 데이터 형식에서 직렬 데이터 형식으로 데이터 형식을 전광으로 변환할 수 있는 전광 직렬-병렬 데이터 형식 변환기의 구조가 제안되었다. 이 구조들은 간단하고 확장이 쉽고 효율적으로 동작하며 쉽게 구현될 수 있다. 제안된 데이터 형식 변환기를 구현하여 동작을 실험적으로 입증하였다.

FBG 센서를 이용한 강연선 전달길이 측정

이성철,최송이,신경준,김재민,이환우,Lee, Seong-Cheol,Choi, Song-Yi,Shin, Kyung-Joon,Kim, Jae-Min,Lee, Hwan-Woo 한국전산구조공학회 2015 한국전산구조공학회논문집 Vol.28 No.6

In this paper, an experimental program has been conducted to investigate transfer length in high strength concrete members pretensioned through a seven-wire strand with FBG sensors. To measure transfer length, five members were fabricated, which had a length of 3 m and a cross-section of $150{\times}150mm$. It was measured that the concrete compressive strength was 58MPa at pretensioning. Test results indicated that more precise and reliable measurement on the transfer length was attained with FBG sensors than conventional gauges attached on concrete surface. Through comparing the measured transfer length and predictions, applicability of several transfer length models in literature was investigated. This paper can be useful for relevant research field such as investigation on the bond mechanism of a seven-wire strand in concrete members. 본 논문에서는 프리텐션된 고강도 콘크리트 부재에서의 전달길이를 측정하기 위해 FBG 센서가 기입된 스마트 강연선을 활용하여 실험을 수행하였다. 전달길이 측정을 위해 길이 3m, 단면 $150{\times}150mm$의 고강도 콘크리트 시험체를 총 5개 제작하였으며, 프리텐션 도입 시 콘크리트 압축강도는 58MPa로 측정되었다. 실험 결과 콘크리트 표면에 부착하는 기존의 전기 저항식 게이지보다 FBG 센서로부터 보다 정밀하고 신뢰성있는 강연선의 전달길이를 계측할 수 있는 것으로 나타났다. 계측결과로부터 산정된 강연선 전달길이를 기존의 여러 모델들과 비교하였으며, 이를 통해 고강도 콘크리트 부재에서의 전달길이 산정에 대한 기존 모델들의 적용성을 분석하였다. 본 연구 내용은 향후 강연선의 부착 특성 분석 등의 관련 분야 연구 등에 유용할 것으로 기대된다.

유한요소법에 의한 박판곡선부채의 좌굴해석

이성철,Lee, Sung Chul 대한토목학회 1991 대한토목학회논문집 Vol.11 No.2

A computer program for the linear elastic buckling anlalysis of thin walled members is developed using a 3-node triangular shell element. The element has real stiffness value for a kinematic degree of freedom associated with rotation about the surface normal at each node. The validity of the present computer program is demonstrated through the plate buckling analysis and the lateral-torsional buckling analysis of a straight beam. Then, simply supported circular arches subjected to uniform bending are analyzed and the results are compared with existing solutions. 평면내에서의 비틀림에 대한 강성도를 갖는 3절점 삼각형 shell요소를 사용하여 박판으로 이루어진 곡석 또는 직선부재의 선형 탄성좌굴 해석을 위한 컴퓨터 프로그램을 개발 하였다. 판의 좌굴 해석과 보의 횡 비틈 좌굴해석을 통하여 본 프로그램의 타당성을 입증하였고, 이를 순수 휨을 받는 양단의 단순지지된 원호 아치의 좌굴해석에 적용시켜 그 결과들을 다른 연구 결과들과 비교 검토하여 보았다.

소아의 이소성 경부흉선 1예

이성철,양석진,김우기,Lee, Seong-Cheol,Yang, Seok-Jin,Kim, Woo-Ki 대한소아외과학회 1996 소아외과 Vol.2 No.1

Aberrant migration of thymic tissue occurs as an ectopic thymus in the mediastinum, base of skull, tracheal bifurcation, and cervical region. A recent review of the literature by Nowak et al. showed over 70 reported cases of aberrant thymus or thymic cyst in patients who presented with primary neck masses. Authors experienced a case of ectopic cervical thymus and reviewed the literature. A one-year-old boy with left neck swelling which had been noticed since one month of age visited out patient clinic. Ultrasonography showed a well-defined cystic mass containing homogeneous, low-echogenic content locating in the lateral aspect of the left carotid sheath. Operation was performed under the impression of branchial cleft cyst. At surgery, a multiseptated, well-encapsulated, brownish and doughy mass which was extending into the vicinity of the carotid bifurcation with sland stalk-like portion ending between the hypoglossal nerve and external carotid artery was excised completely. The cut-surface showed homogenous solid mass, and on frozen section the tissue revealed a normal thymic histology. Postoperative ultrasonography showed bilateral thymus in the superior mediastinum. The patient has no immunologic problem and is doing well now. 1세된 남아에서 세열낭종을 의심한 좌측 경부 종양이 수술을 시행한 결과 고형종양이였고, 조직검사상 이소성 흉선으로 판명되었다. 술후 초음파상 흉선은 정상적으로 있었고, 현재 환자의 면역기능은 아무 이상없이 정상으로 자라고 있다.

냉간 압축 하에서 금속 분말의 치밀화 거동

이성철,김기태,Lee, Seong-Cheol,Kim, Gi-Tae 대한기계학회 2002 大韓機械學會論文集A Vol.26 No.1

Densification behavior of aluminum alloy(A16061) powder was investigated under cold compaction. Experimental data were obtained under triaxial compression with various loading conditions. A special form of the Cap model was proposed from experimental data of A16061 powder under triaxial compression. The proposed yield function and several yield functions in the literature were implemented into a finite element program (ABAQUS) to compare with experimental data for densifcation behavior of A16061 powder under cold isostatic pressing and die compaction. The agreement between finite element calculations from the proposed yield function and experimental data is very good under cold isostatic pressing and die compaction.

타원형 기어의 와이어커팅을 위한 설계

이성철,Lee, Sung-Chul 한국트라이볼로지학회 2007 한국트라이볼로지학회지 (Tribol. Lubr.) Vol.23 No.4

The CAD model of a elliptical gear for wire cutting has been developed. The rolling contact of pitch ellipses whose rotation axes coincide with their focus has been analyzed, and the perimeter of the pitch ellipse has been divided into equal-length segments by the number of teeth. A master tooth profile, which is a composite curve of circular arcs that represents involute, has been introduced. The elliptical gear has been designed by imposing the master tooth on the divided points of the pitch ellipse, and a full fillet has been achieved between neighbour teeth. Thus, the whole profile of an elliptical gear is a composite curve of arcs only, and consequently NC codes for wire cutting can be easily generated. Furthermore, a computer simulation program is developed to verify the mesh of the elliptical gear.

유관 압박나사를 이용한 거골하 관절유합술

이성철,정홍근,전지용,유제욱,Lee, Sung-Chul,Jung, Hong-Geun,Chun, Ji-Yong,Yu, Je-Wook 대한족부족관절학회 2005 대한족부족관절학회지 Vol.9 No.1

Purpose: To analyze the overall clinical outcome, overall assessment, and patient's satisfaction rate of subtalar arthrodesis using the cannulated compression screw. Materials and Methods: This study is based on 17 patients, 17 feet who underwent subtalar arthrodesis using the cannulated compression screw from March, 1997 to March, 2004 with at least 1 year follow-up. The average follow-up period was 33.0 months (12 to 72 months). Functional results were assessed using the American Orthopaedic Foot and Ankle Society Ankle-Hindfoot (AOFAS) score, and Visual Analysis Scale (VAS) pain score, patients' returning to previous occupation and patients' satisfaction rate were also evaluated. Results: The mean AOFAS scores at final follow-up were 80.4 points (range $66{\sim}92$). The satisfactory rates were as follow. Thirteen patients (76.4%) were at least satisfied with surgical result at final follow-up. Patients' VAS pain score was average 2.8 points ($1{\sim}6$). Fourteen (82.3%) patients returned to previous job at mean postoperative period of 11.3 months (range 3-18 months). Patients' work efficiency after returning to previous occupation was 68.7% (range $33{\sim}100%$). There were 9 complications which were 3 cases of sural nerve injury, 1 case of valgus malunion, and 5 cases of the hindfoot residual pain. Conclusion: We obtained the satisfactory functional results with relatively high patient satisfaction rate of 76%. So we conclude that subtalar arthrodesis using the cannulated compression screw is a reliable method for addressing the painful end-stage subtalar osteoarthritis and unreconstructible comminuted calcaneal fractures. However we also found out that average 11 months were necessary for patients to return to their job.

담도 폐쇄증에서 광범위 간문부 절제 및 간문부-공장 문합술의 치료성적

이성철,Lee, Seong-Cheol 대한소아외과학회 1997 소아외과 Vol.3 No.2

Extended porta hepatis dissection and hepatic portojejunostomy was performed on 14 biliary atresia patients during last 13 years by a single surgeon. The average age at operation was 68 days(range from 37 days to 98 days). The patients were admitted for 8 weeks postoperatively for administration of parenteral antibiotics. There was one operative mortality due to acute hepatic necrosis. Among 13 patients remaining, 12(92.5 %) became chemically jaundice-free within 36 weeks postoperatively(average 16.8 weeks). the earliest 8 weeks, and in one patients jaundice persisted. Five(38.5 %) patients developed cholangitis after operation. Among jaundice-free patients, one patient died of unrelated disease 2 years after hepatic portojejunostomy, who underwent left lateral segmentectomy because of a biloma. Eleven survivors(78.6 %) are jaundice-free. The oldest one is 13 years old, enjoying a normal life. The mean period of follow-up is 7 years and 3 months.

가와사끼 병에 합병된 간기능 이상소견에 대한 임상적 및 병리조직학적 소견

이성철,차한,나송이,김희섭,박호진,신미경,Lee, Sung-Chul,Tchah, Hann,Na, Song-Yi,Kim, Hee-Sup,Park, Ho-Jin,Shin, Mi-Kyeong 대한소아소화기영양학회 2000 Pediatric gastroenterology, hepatology & nutrition Vol.3 No.1

Purpose: The aim of this research is to examine the abnormal liver function complicated with Kawasaki disease (KD) and to analyze its clinical characteristics and complications. Methods: Ninty eight cases were diagnosed as having KD, among which thirty four cases had abnormal alanine aminotransferase (ALT) (>30 IU/L). These abnormal ALT cases were evaluated in terms of age and sex distribution, major symptoms, complications, laboratory and histopathologic findings. Results: Male to female ratio was 2.4:1 and most patients (91.2%) were under 5 years of age. Cervical lymphadenopathy was observed in 3 cases (8.8%); and recurred cases were two (5.8%). Average fever duration was 8 days; average length of hospitalization was 9 days; and average recovery period was 13 days. Immediately after admission, positive CRP was observed in 31 cases (91.2%), leukocytosis (> $10,000/mm^3$) in 26 cases (76.0%), thrombocytosis (> $450,000/mm^3$) in 7 cases (20.6%), and anemia (<10 gm/dl) in 7 cases (20.6%), respectively. GB hydrops or cholecystitis were noted in 3 cases (8.8%), abnormal ECG finding in 1 case (2.9%), coronary dilatation or aneurysm in 2 cases (5.9%). Liver biopsy was done in four cases and revealed mild infiltration of lymphocytes on the portal area and mild bile duct proliferations. Conclusion: The abnormal liver function was noted in 34.7% of KD patients, and subsided all within one month. But the liver function test should be checked closely in patients of the abnormal liver function test complicated with KD despite of its good prognosis.

뇌실복강간 단락술(Ventriculoperitoneal Shunt)을 시행한 환자에서의 서혜부 탈장의 빈도와 특성

이성철,이혁준,김기홍,정성은,박귀원,김우기,Lee, Seong-Cheol,Lee, Hyuk-Joon,Kim, Ki-Hong,Chung, Sung-Eun,Park, Kwi-Won,Kim, Woo-Ki 대한소아외과학회 2000 소아외과 Vol.6 No.2

Ventriculoperitoneal shunt(VP shunt) for hydrocephalus is thought to inhibit the closure of processus vaginalis and promote inguinal hernia by increasing intraabdominal pressure. To estimate the patency rate of processus vaginalis and the incidence and characteristics of the inguinal hernia, 262 cases of VP shunt in early childhood between January 1980 and May 1998 at Seoul National University Children Hospital were reviewed retrospectively. Inguinal hernia developed in 28 cases(10.7 %), but six patients had an inguinal hernia before the VP shunt was placed. Patients who had a VP shunt before 6 months of age developed inguinal hernia in 16.2 %(12/74) of cases, patients shunted between 6 months and 2 years had an incidence of 12.4 %(11/89) and only 5.1 %(5/99) of patients operated upon after 2 years of age developed hernias. Twenty-two patients out of 256 cases (8.6 %) developed inguinal hernia after VP shunt, with male predominance(M : F=4.5:1). Eight patients developed inguinal hernia bilaterally(36.4 %). It is suggested that at least 14% of processus vaginalis is patent until 2 years old.