• Journal of Chest Surgery
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• v.34 no.6
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• pp.465-471
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• 2001

Background: Hypothermia protects the brain by suppressing the cerebral metabolism and it is performed well enough before the total circulatory arrest(TCA) in the operation of aortic disease. Generally, TCA has been performed depending on the rectal or nasopharyngeal temperatures; however, there is no definite range of optimal temperature for TCA or an objective indicator determining the temperature for safe TCA. In this study, we tried to determine the optimal range of temperature for safe hypothermic circulatory arrest by using the intraoperative electroencephalogram(EEG), and studied the role of EEG as an indicator of optimal hypothermia. Material and Method: Between March, 1999 and August 31, 2000, 27 patients underwent graft replacement of the part of thoracic aorta using hypothermia and TCA with intraoperative EEG. The rectal and nasopharyngeal temperatures were monitored continuously from the time of anesthetic induction and the EEG was recorded with a ten-channel portable electroencephalography from the time of anesthetic induction to electrocerebral silence(ECS). Result: On ECS, the rectal and nasopharyngeal temperatures were not consistent but variable(rectal 11$^{\circ}C$ -$25^{\circ}C$, nasopharynx 7.7$^{\circ}C$ -23$^{\circ}C$). The correlation between two temperatures was not significant(p=0.171). The cooling time from the start of cardiopulmonary bypass to ECS was also variable(25-127min), but correlated with the body surface area(p=0.027). Conclusion: We have found that ECS appeared at various body temperatures, and thus, the use of rectal or nasopharyngeal temperature were not useful in identifying ECS. Conclusively, we can not fully assure cerebral protection during hypothermic circulatory arrest in regards to the body temperatures, and therefore, the intraoperative EEG is one of the necessary methods for determining the range of optimal hypothermia for safe circulatory arrest. :

• Journal of Chest Surgery
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• v.34 no.10
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• pp.733-744
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• 2001

Background: The optimal therapeutic strategies for patients with coarctation of the aorta(CoA) and ventricular septal defect(VSD) remain controversial. This study was undertaken to determine the outcome and the need for reintervention following single-stage repair of coarctation with VSD in infants younger than 6 months. Material and Method: Thirty three consecutive patients who underwent single-stage repair of CoA with VSD, from January 1995 to December 2000, at Sejong General Hospital were reviewed retrospectively. Mean age and body weight at repair were 54$\pm$37 days(12 days-171 days) and 3.9$\pm$1.1 kg(1.5~6 kg), respectively. The surgical repair of CoA was performed under deep hypothermic circulatory arrest(CA) in the early period of the study and under regional cerebral perfusion through a direct innominate arterial cannulation without CA in the later period. The technique used in the repair of the CoA was resection and extended end-to-end anastomosis(EEEA; n=16) and extended side-to-side anastomosis(ESSA; n=2) in the early period, and resection and extended end-to-side anastomosis(EESA; n= 15) in the later period. The simultaneous closure of VSD was done with a Dacron patch(n= 16) and autologous pericardium(n=17). Aortic arch hypoplasia was present in 29 patients(88%) and its types were distal(n=18), complete(n=5), and complex(n=6)

• Journal of Chest Surgery
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• v.34 no.12
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• pp.924-929
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• 2001

Backgroun : The long-term survival after operation of patients with lung cancer invading the chest wall is known to be related to regional nodal involvement, completeness of resection and depth of chest wall involvement. In this study results of complete resection are reviewed to determine survival charateristics. Material and Method: Of 680 consecutive patients who were operated on for primary non-small cell carcinoma between 1988 and 1998, we retrospectively reviewed 55 patients(8.0%) who had complete resection for lung cancer invading the chest wall or parietal pleura. Result: Resection of the chest wall was on bloc in 29 patients(47.3％), and extrapleural in 26(52.7％). In the patients undergoing extrapleural resection, the depth of chest wall invasion was confined to the parietal pleura in all patients(100%). In the patients underging en bloc resection, the pathologic depth of invasion was into the parietal pleura alone in 9(31.0%) and into the chest wall in 20(69.0%). The follow-up rate of these patients was 100%. Hospital mortality was 5.4%(n=3). The actuarial 5-year survival rate was 26% for all hospital survivors(n=52). The actuarial 5-year survival rate of patients with T3N0M0 disease(29%) was better than that of T3N2M0 disease(18%), however, there was no significant(p=0.30) difference. The depth of chest wall invasion had no statistically significant effect on survival in our series, neither for patients with involved lymphatic metastasis nor for those without(p=0.99). Conclusion: These observations indicate that the good five year survival in patients with T3 NSCLC invading the chest wall resulted from complete resection. Survival of patients with lung cancer invading the chest wall after complete resection is dependent on the extent of nodal involvement and much less so on the depth of chest wall invasion.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.32 no.4
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• pp.249-256
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• 2019

This paper presents an optimization framework of electrical impedance tomography for characterizing electrical conductivity profiles of concrete structures in two dimensions. The framework utilizes a partial-differential-equation(PDE)-constrained optimization approach that can obtain the spatial distribution of electrical conductivity using measured electrical potentials from several electrodes located on the boundary of the concrete domain. The forward problem is formulated based on a complete electrode model(CEM) for the electrical potential of a medium due to current input. The CEM consists of a Laplace equation for electrical potential and boundary conditions to represent the current inputs to the electrodes on the surface. To validate the forward solution, electrical potential calculated by the finite element method is compared with that obtained using TCAD software. The PDE-constrained optimization approach seeks the optimal values of electrical conductivity on the domain of investigation while minimizing the Lagrangian function. The Lagrangian consists of least-squares objective functional and regularization terms augmented by the weak imposition of the governing equation and boundary conditions via Lagrange multipliers. Enforcing the stationarity of the Lagrangian leads to the Karush-Kuhn-Tucker condition to obtain an optimal solution for electrical conductivity within the target medium. Numerical inversion results are reported showing the reconstruction of the electrical conductivity profile of a concrete specimen in two dimensions.

• Proceedings of the Korean Fiber Society Conference
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• 2003.04a
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• pp.187-190
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• 2003

복잡한 형상을 지나는 고분자 유체의 유동 해석은 학문적인 관심 뿐만 아니라 고분자 가공 공정을 이해하는데 많은 도움을 주기 때문에 산업적으로도 그 중요성이 높다. 그러나, 기하학적 복잡성이나 재료 자체의 비선형성으로 인하여 해석적인 접근에 한계가 있기 때문에 다양한 수치 해석법을 이용한 유동 해석이 주를 이루고 있다. 특히 고분자 가공 공정의 수치 모사에 있어서는 수치 해석법을 적용하는데 있어서도 완전한 3차원 해석보다는 여러 가지 가정을 적용한 2차원 내지는 2.5차원 해석이 주를 이루고 있어서도 완전한 3차원 해석보다는 여러 가지 가정을 적용한 2차원 내지는 2.5차원 해석이 주를 이루고 있는 실정이다. (중략)

• Proceedings of the Korean Society for Information Management Conference
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• 1997.08a
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• pp.117-120
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• 1997

KCR3과 AACR2R이 온라인 환경 즉, 온라인 목록에 부합되도록 실제적인 개선방안을 제시하고 있다. 구두법과 약자, 즉 몇몇 구두법에 대한 재정리 및 약자에 대한 완전철자 사용, masterfile에서의 청구기호의 위치, 서명저자사항에서 공저서 및 공저자 등의 생략없는 완전한 나열, 주기사항에 내용 및 목차주기의 제공, 표목지시로 이용자에게 다양한 접근점의 부출 등을 제시함으로서 온라인 목록에 부합되는 합리적인 편목규칙이 성립될 수 있을 것이다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.11a
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• pp.230-230
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• 2009

가스절연 개폐장치 (Gas Insulated Switchgear : GIS)의 고체 스페이서에 경사 기능성 재료 (Functionally Graded Material : FGM)가 적용될 때, 절연성능이 크게 향상된다. 본 논문에서는 FGM 스페이서가 적용된 GIS의 전극 및 스페이서의 형상을 변경하여 최대전계를 완화시켰다. 이를 위해 완전요인실험 (Full Factorial Design : FFD)과 결합된 반응표면법 (Response Surface Methodology : RSM)의 최적화기법을 이용하여, 전극 및 스페이서의 최적 형상을 설계하였다.

• Proceedings of the Korea Association of Information Systems Conference
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• 1997.10a
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• pp.105-112
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• 1997

전자상거래(Electronic Commerce)를 광범위하게 활용하기 위해서는 시큐리티 확 보 방안이 먼저 마련되어야 한다. 전자상거래와 관련된 시큐리티 문제에는 통상적인 정보보 안 이외에 메시지 발신자의 신원을 증명하는 신원 인증과, 메시지 내용의 완전성 및 정확성 을 보장하는 메시지의 완전성 보장, 그리고 메시지의 송·수신을 증명하는 부인방지 등이 있 다. 본 논문에서는 전자상거래의 시큐리티 문제를 해결하는데 필요한 메시지 인증과 디지털 서명에 대해 소개하고, 또한 메시지 인증과 디지털 서명의 핵심적인 요소인 해쉬함수를 분 석한다.

• Proceedings of the Optical Society of Korea Conference
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• 2002.07a
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• pp.154-155
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• 2002

완전 광 3R(Retiming, Reshaping, Reamplification) 재생기는 WDM 시스템과 광 네트워크의 크기를 확장시키기 위하여 필요한 매우 중요한 소자이다. 완전 광 3R 재생기의 구현에서 입력 광 신호로부터 광 클락 추출은 가장 핵심적인 요소이다. 이러한 광 클락 추출을 위하여 모드락 레이저 다이오드와 다중 전극 DFB 레이저에서 self-pulsating 현상을 이용하는 방법이 많이 연구되고 있다. 독일의 HHI는 다중 전극 DFB 레이저에서 self-pulsating 현상을 이용하여 80 GHz 초고속 광 클락 추출과 25-82 GHz 전기적 튜닝 특성을 보였다. (중략)

• 월간 기계설비
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• s.237
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• pp.62-64
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• 2010

한국토지주택공사가 입찰업체 심사과정을 완전공개 하는 새로운 입찰심사제도를 도입하는 등 입찰 업체선정을 둘러싼 잡음을 제거하기 위해 발 벗고 나섰다. 한국토지주택공사(사장 이지송, 이하 LH)는 건설부조리를 뿌리 뽑고 기술력만으로 경쟁하는 공정한 입찰질서를 확립하기 위하여 "투명한 심사조직, 깨끗한 심사위원, 공정한 심사제도"를 모토로 LH 만의 독자적인 심사제도인 '투명하고 공정한 LH클린심사제도'를 마련 운영키로 했다. 이에 따라 지난 3월 4일부터 6일까지 시행하는 보금자리주택 2차 시범지구(구리갈매, 부천옥길, 시흥은 계) 설계용역 및 아산배방, 인천청라 U-City 구축사업 심사부터 성공적으로 적용했고, 앞으로 시행할 영종자동크린넷 등 모든 턴키심사에 적용한다고 밝혔다.