구조응력을 이용한 하중 전달형 십자 양면 비대칭 필렛 용접 시험편의 피로강도 평가

김성민,김영남,이승현,김명현,Kim, Seong-Min,Kim, Young-Nam,Lee, Seung-Hyun,Kim, Myung-Hyun 대한용접접합학회 2012 대한용접·접합학회지 Vol.30 No.6

Fatigue tests and analyses were carried out to investigate fatigue strength and crack initiation point of load-carrying asymmetric double bevel cruciform welded joints. Mesh-insensitive structural stress approach was adopted to estimate high precise fatigue life and crack initiation point. Two different case material and weld shape were considered in this study. Results of fatigue tests and analyses were compared and discussed in consideration of applicability of structural stress approach as the reliable fatigue assessment method of cruciform welded joints.

2005년도 소아 서혜부 탈장치료 경향

김성민,김대연,김상윤,김성철,김우기,김재억,김재천,박귀원,서정민,송영택,오정탁,이남혁,이두선,전용순,정상영,정을삼,최금자,최순옥,한석주,허영수,홍정,최승훈,Kim, Seong-Min,Kim, Dae-Yeon,Kim, Sang-Yoon,Kim, Seong-Chul,Kim, Woo-Ki,Kim, Jae-Eok,Kim, Jae-Chun,Park, Kwi-Won 대한소아외과학회 2006 소아외과 Vol.12 No.2

Inguinal hernia is the most common disease treated by the pediatric surgeon. There are several controversial aspects of management 1)the optimal timing of surgical repair, especially for preterm babies, 2)contralateral groin exploration during repair of a clinically unilateral hernia, 3)use of laparoscope in contralateral groin exploration, 4)timing of surgical repair of cord hydrocele, 5)perioperative pain control, 6)perioperative management of anemia. In this survey, we attempted to determine the approach of members of KAPS to these aspects of hernia treatment. A questionnaire by e-mail or FAX was sent to all members. The content of the questionnaire were adapted from the "American Academy of Pediatrics (AAP) Section on Surgery hernia survey revisited (J Pediatr Surg 40, 1009-1014, 2005)". For full-term male baby, most surgeons (85.7 %) perform an elective operation as soon as diagnosis was made. For reducible hernia found in ex-preterm infants already discharged from the neonatal intensive care unit (NICU), 76.2 % of surgeons performed an elective repair under general anesthesia (85.8 %). 42.9 % of the surgeons performed the repair just before discharge. For same-day surgery for the ex-premature baby, the opinion was evenly divided. For an inguinal hernia with a contralateral undescended testis in a preterm baby, 61.9 % of surgeons choose to 'wait and see' until 12 month of age. The most important consideration in deciding the timing of surgery of inguinal hernia in preterm baby was the existence of bronchopulmonary dysplasia (82.4 %), episode of apnea/bradycardia on home monitoring (70.6 %). Most surgeons do not explore the contralateral groin during unilateral hernia repair. Laparoscope has not been tried. Most surgeons do not give perioperative analgesics or blood transfusion.

Synthesis and Application of the Novel Azomethine Metal Complexes for the Organic Electroluminescent Devices

김성민,김진순,신동명,김영관,하윤경,Kim, Seong Min,Kim, Jin Sun,Sin, Dong Myeong,Kim, Yeong Gwan,Ha, Yun Gyeong Korean Chemical Society 2001 Bulletin of the Korean Chemical Society Vol.22 No.7

New azomethine metal complexes were synthesized systematically and characterized. Beryllium, magnesium, or zinc ions were used as a central metal cation and aromatic azomethines (L1-L4) were employed as a chelating anionic ligand. Emission peaks o f the complexes in both solution and solid states were observed mostly at the region of 400-500 nm in the luminescence spectra, where blue light was emitted. Three of them (BeL1 (Ⅰ), ZnL2 (Ⅱ), and ZnL3 (Ⅲ)) were sublimable and thus were applied to the organic light-emitting devices (OLED) as an emitting layer, respectively. The device including the emitting layer of Ⅰ exhibited white emission with the broad luminescence spectral range. The device with the emitting layer of Ⅱ showed blue luminescence with the maximum emission peak at 460 nm. Their ionization potentials, electron affinities, and electrochemical band gaps were investigated with cyclic voltammetry. The electrochemical gaps of 2.98 for I, 2.70 for Ⅱ, and 2.63 eV for Ⅲ were found to be consistent with their respective optical band gaps of 3.01, 2.95 and 2.61 eV within an experimental error. The structure of OLED manufactured in this study reveals that these complexes can work as electron transporting materials as well.

상장간막동맥 증후군의 복강경 수술 및 3차원재건 복부 전산화단층촬영 영상을 이용한 추적관찰 -1예보고-

김성민,김성훈,권인규,김명준,형우진,최승훈,Kim, Seong-Min,Kim, Sung-Hoon,Kwon, In-Kyou,Kim, Myoung-Joon,Hyoung, Woo-Jin,Choi, Seung-Hoon 대한소아외과학회 2005 소아외과 Vol.11 No.2

Superior mesenteric artery (SMA) syndrome is a rare disorder caused by extrinsic compression of the third portion of the duodenum by the SMA. The operative treatment of choice is bypassing the obstructed duodenal segment by duodenojejunostomy. We report one case of SMA syndrome treated by laparoscopic duodenojejunostomy and followed up by 3D-reconstructive CT scan. A fifteen-year-old boy with intermittent vomiting and weight loss was admitted. Ultrasonography showed narrowing of the distance between the SMA and aorta. Hypotonic duodenography showed dilatation of duodenal third portion and barium stasis. On 3Dreconstructive CT scan, the angle between SMA and aorta was $37^{\circ}$. The postoperative course was uneventful. Three months later, he had gained 3 kg of weight and the angle between SMA and aorta increased to $38-39^{\circ}$ on 3D reconstructive CT scan. Laparoscopic duodenojejunostomy for bypassing the obstructive duodenum in SMA syndrome is a feasible and safe method.

잔존 총배설강 기형 수술 후 발생한 요도-질 누공에 대한 전방 시상 경직장적 접근 술식 (Anterior Sagittal Transrectal Approach, ASTRA) 1 례보고

김성민,김창우,김병규,오정탁,한석주,Kim, Seong-Min,Kim, Chang-Woo,Kim, Byoung-Kyu,Oh, Jung-Tak,Han, Seok-Joo 대한소아외과학회 2007 소아외과 Vol.13 No.1

The authors applied anterior sagittal transrectal apporach (ASTRA) for the repair of urethrovaginal fistula which developed after total repair of persistent cloaca. The patient had been diagnosed to have persistent cloaca, double uterus and double vagina, and received PSARP, excision of right-side uterus and vagina, and left vaginal switch operation at 22 months old. After operation, the patient admitted several times due to frequent urinary tract infection and ectopic stone formation in bladder and neovagina. Urethro-neovaginal fistula was confirmed by cystoscopy and corrected with ASTRA. Postoperative voiding cystourethrogram showed no fistula tract. ASTRA showed improved surgical field, minimized ureterocystic damage, and preserved perirectal nerve due to limited incision of rectum.

신설 프리캐스트 콘크리트 포장 시공방법 및 설계지침 개발

김성민,박희범,양성철,한승환,Kim, Seong-Min,Park, Hee-Beom,Yang, Sung-Chul,Han, Seung-Hwan 한국도로학회 2008 한국도로학회논문집 Vol.10 No.2

This study was conducted to investigate the feasibility of the expedite construction of new pavement systems using precast concrete slabs and to develop the design and construction guide based on the results of the experimental construction. Half scale concrete slabs were designed and fabricated and the optimal reinforcement design, linkages between the slabs in the longitudinal and transverse directions, and the grouting methods were investigated. The experimental construction was performed fast and easily by assembling two slabs in the longitudinal direction and the other two in the transverse direction. The slabs were leveled and the pockets and the space between the slab bottom and the underlying layer were grouted. From the experimental construction, details about the design and construction of the precast pavements were acquired. Finally, the design and construction guide for the newly constructed precast concrete pavement systems was developed. 본 연구는 프리캐스트 콘크리트 슬래브를 이용한 급속 신설 도로 포장 공법의 국내 적용성을 분석하기 위한 기초 연구를 수행하고 시험시공을 통해 선설 프리캐스트 포장의 설계 및 시공 지침을 개발하기 위하여 수행되었다. 시험시공을 위해 가로, 세로, 깊이가 각각 실제 포장 슬래브의 1/2 크기인 슬래브를 설계하여 제작하였으며 이에 적합한 철근배근, 종방향과 횡방향의 연결부, 그라우팅 방법 등에 대하여 분석을 수행하였다. 이러한 슬래브를 이용하여 종방향과 횡방향으로 두 개씩 총 4 개의 슬래브를 연결하여 평탄성을 조절한 후 포켓 부분과 슬래브 하부의 공간을 그라우팅 함으로써 시공을 신속 용이하게 수행하였다. 시험 시공을 수행하며 프리캐스트 포장의 설계 및 시공과 관련된 세부 사항을 면밀히 분석하였으며 이에 바탕을 두어 프리캐스트 슬래브를 이용하여 급속하게 신설 도로를 건설할 때의 설계 및 시공 지침을 개발하였다.

Analysis Models of Concrete Slabs-on-Grade Considering Horizontal Resistance at Slab Bottom and Behavior under Thermal Loads

김성민,안주옥,Kim Seong-Min,An Zu-Og Computational Structural Engineering Institute of 2006 한국전산구조공학회논문집 Vol.19 No.3

The behavior of the concrete slabs on grade considering the horizontal resistance at the slab bottom, which exists due to the shear resistance of the foundation and the friction between the slab and the foundation, has been investigated when the slabs-on-grade are subjected to the thermal load. Analytical formulations have been developed to include the effect of the horizontal resistance at the slab bottom employing the thin plate on an elastic foundation that is widely used for the analysis of concrete slabs-on-grade and rigid pavement systems. Finite element formulations have then been developed using the plate bending elements and the flat shell elements. The solutions from the analytical and numerical models have been compared and showed very good agreement. The sensitivity of the horizontal resistance to the stresses of the concrete slab has been investigated with various values of the slab thickness, elastic modulus, and vortical stiffness of the foundation when subjected to the temperature gradient between the top and bottom of the slab and the uniform temperature drop throughout the slab depth. The analysis results show that the horizontal resistance at the plate bottom can significantly affect the stresses of the slab when the thermal loads are applied. 지반위에 놓인 콘크리트 슬래브가 온도하중을 받을 때 지반의 전단저항과 슬래브 하부와 지반과의 마찰 등에 의해 생기는 슬래브 하부의 수평저항을 고려하여 지반위에 놓인 콘크리트 슬래브의 거동을 분석하였다. 지반위의 콘크리트 슬래브와 강성도로포장의 해석에 널리 사용되는 탄성지반위의 얇은 판을 이용하여 슬래브 하부의 수평저항을 고려하기 위한 해석 공식을 유도하였다. 이를 이용하여 판요소와 쉘요소를 이용한 유한요소법에 의한 모델을 개발하여 수치해석 결과를 도출하였다. 해석 공식과 수치해석 모델을 이용한 해석 결과를 비교 분석하였고 매우 비슷한 결과가 도출 되는 것을 알 수 있었다. 슬래브의 상부와 하부에 온도 차이가 있을 때와 슬래브의 온도가 전체적으로 감소할 때, 콘크리트 슬래브의 응력 분포에 슬래브 하부의 수평저항이 미치는 민감성을 여러 가지의 다른 슬래브의 두께, 탄성계수, 그리고 지반의 수직탄성계수 등을 고려하여 분석하였다. 해석 결과에서 온도하중을 받을 때 슬래브 하부의 수평저항은 슬래브의 응력에 매우 큰 영향을 미칠 수 있다는 것을 발견하였다.

측정 불확도 이론 및 사례 연구(1)

김성민,Kim, Seong-Min 한국제품안전협회 2008 제품안전 Vol.170 No.-

경쟁입찰방식을 이용한 최초공모주의 발행가격결정에 관한 연구

김성민,Kim, Seong-Min 한국재무관리학회 1998 財務管理論叢 Vol.4 No.1

기존의 최초공모주 발행제도하에서는 일반투자자의 공모주식수요에 대한 의사가 공모가 결정과정에 반영될 수 있는 기회가 없음으로 인해 최초공모주의 심각한 저가발행 현상이 나타나고 있다. 이에 대한 문제점을 보완 개선하기 위하여 본 연구는 기업공개시 주식매각의 한 방안으로 경쟁입찰방식을 제시하였으며, 우리 나라 실정에 맞는 입찰모형의 설정을 위한 제반요인들을 조사 분석하였다. 또한, 경쟁입찰방식을 통한 최초공모주 발행의 장점과 경쟁입찰방식과 관련하여 예상되는 경제적 제 문제들을 공개입찰을 통한 장외등록기업 사레와 공기업민영화 사례를 통해 간접적으로 유추 검토하였다. 경쟁입찰방식하에서는 발행기업의 진실된 가치와 시장투자자들의 최초공모주에 대한 수요의사가 입찰과정을 통해 최적공모가격 결정에 적절히 반영되어 기존의 발행방식과 비교해 저평가율도 낮아질 것으로 기대되며, 심각한 문제가 없을 것이라는 판단하에 본 논문은 경쟁입찰방식을 통한 최초공모주발행이 기존의 발행방식에 대한 하나의 경제적 대안으로 선호될 수 있음을 보여 주었다.

라플라스 신호원에 대한 최소평균제곱오차 홑 양자기의 지지역에 관하여

김성민,나상신,Kim, Seong-Min,Na, Sang-Sin 한국통신학회 2006 韓國通信學會論文誌 Vol.31 No.10C

이 논문은 라플라스 밀도 함수에 대한 최적 흩 양자기의 지지역의 증가는 양자점의 개수와 대수적인 관계가 있음을 보여준다. 구체적으로, 분산이 1인 라플라스 밀도함수에 대해서 양자정의 개수 N이 증가할 때 최적 양자기의 경계값에 의해 결정되는 지지역과 $\frac 3{\sqrt{2}}1n\frac N 2$의 비율이 1로 수렴함을 보여준다. 또한 극한 상한값을 유도하여 최적 지지역의 로그적 증가가 그 값을 초과하지 않음을 보였다. 이 결과들로부터 이전부터 경험적으로 연구되어 온 최적 지지역의 로그 증가를 확인 할 수 있다. This paper shows that the support growth of an optimum (minimum mean square-error) scalar quantizer for a Laplacian density is logarithmic with the number of quantization points. Specifically, it is shown that, for a unit-variance Laplacian density, the ratio of the support-determining threshold of an optimum quantizer to $\frac 3{\sqrt{2}}1n\frac N 2$ converges to 1, as the number of quantization points grows. Also derived is a limiting upper bound that says that the optimum support cannot exceed the logarithmic growth by more than a constant. These results confirm the logarithmic growth of the optimum support that has previously been derived heuristically.