• Proceedings of the Korea Institute of Fire Science and Engineering Conference
• /
• 2010.04a
• /
• pp.333-339
• /
• 2010

본 연구는 제연구역 출입문의 자동폐쇄장치를 개발하기 위한 기초 연구로서, 자동폐쇄장치의 프로세스와 자동폐쇄조절장치의 기구학적 메커니즘 정립 및 기구 모델링을 바탕으로 자동폐쇄장치의 해석이론을 정립하였고, 해석이론을 바탕으로 한 운동해석 시뮬레이션을 통해 폐쇄력 장치를 선정하고 자동폐쇄조절장치의 각 요소를 개발할 수 있는 엔지니어링 데이터 구축과 원천기술을 확립하였다. 자동폐쇄장치의 개발에 유연성과 탄력성을 줄 수 있고, 자동폐쇄장치의 개발로 인해 연기의 제어수단과 기술적 대책마련과 제연시스템의 높은 신뢰성과 안정성을 확보할 수 있을 것으로 본다.

• Clinical and Experimental Pediatrics
• /
• v.52 no.4
• /
• pp.494-498
• /
• 2009

Purpose : Applicability of transcatheter closure of atrial septal defect (ASD) has been expanded by accumulation of clinical experiences and evolutions of the device. This study was performed to evaluate the safety and efficacy of transcatheter closure of ASD with Amplatzer septal occluder (ASO) in young children less than 3 years of age. Methods : From May 2003 to December 2005, 295 patients underwent transcatheter closure of ASD with ASO in the Severance Cardiovascular Hospital, Yonsei University Health System. Among them, 51 patients less than 3 years of age were enrolled in this study. We investigated procedural success rate, rate of residual shunt, frequency of complications, procedure/fluoroscopy time, and need of modified techniques for device implantation. Results : The median age was 2.1 years and median body weight was 12 kg. Implantation of device was successful in 50 patients (98%). Seven patients (15%) showed a small residual shunt 1 day after the procedure, but complete occlusion had been documented at 6 month follow-up in all patients (100%). The pulmonary to systemic flow ratio (Qp/Qs), peak systolic pulmonary artery pressure, and peak systolic right ventricular pressure had decreased significantly after closure of ASD. There were 2 complications including device embolization (1, 2%) and temporary groin hematoma (1, 2%). Conclusion : Transcatheter closure of ASD with ASO can be performed with satisfactory results and acceptable risk even in young children less than 3 years of age. We could suggest that even in very young children with ASD, there is no need to wait until they grow to a sufficient size for the transcatheter closure.

• Clinical and Experimental Pediatrics
• /
• v.50 no.5
• /
• pp.469-475
• /
• 2007

Purpose : This study was performed to compare the safety, efficacy and clinical results of the Amplatzer septal occluder (ASO) for closure of secundum atrial septal defect (ASD) with surgery. Methods : One hundred fifteen patients diagnosed as isolated secundum ASD in Gil Medical Center, Gachon University of Medicine from January 2000 to July 2006 were included. Seventy patients underwent surgical repair of ostium secundum ASD. Forty-five consecutive patients were treated with percutaneous closure using ASO. We compared the mortality, morbidity, hospital stay, and efficacy between two groups. Results : Male to female ratio was 1:2.4. The mean age and the size of defects were not statistically different. No mortality occurred in either group. The success rate was 97.8% in the device group and 100% in the surgical group. The overall rate of complications was higher in the surgical group than in the device group (64.0 vs. 15.6%, P<0.05). Hospital stay was shorter in the device group than in the surgical group ($4.2{\pm}1.2$ vs. $12.4{\pm}4.7days$, P<0.0001). Residual shunt rates were more frequent in the device group (8.9%) than in the surgical group (4.3%) at discharge. All residual shunts disappeared at 3 months follow-up. Conclusion : Percutaneous closure of ASD using ASO is a safe and effective alternative to surgical repair. The indications of percutaneous ASD closure with ASO would be expanded by accumulation of experiences and evolutions of device.

• Electronics and Telecommunications Trends
• /
• v.28 no.4
• /
• pp.10-22
• /
• 2013

최근 기술발전으로 인해 선박에 디지털 및 전자장비들이 도입되었고, 폐쇄적인 구조에서 IT기반의 개방형, 통합형 형태로 바뀌어가고 있다. 특히, 국제해사기구에서 추진하고 있는 'e-navigation'은 조선 및 선박에 IT 융합의 새로운 패러다임을 제공하고 있다. 이를 위해, 관련된 국제 표준화 기구들에서는 다양한 표준들을 제정 또는 개정 중에 있다. 본고에서는 조선 IT 관련 국제 표준화 기구들에 대해 소개하고, 각 표준화 기구의 역할과 최근 동향에 대해서 살펴보았다. 그리고, 낙후된 국내 조선 기자재 산업을 위한 향후 국제 표준화 방향에 대해 정리하였다.

• Fire Science and Engineering
• /
• v.24 no.3
• /
• pp.106-112
• /
• 2010

This study carried out the motion analysis of auto closing systems as basis study for development of auto closing systems for door in smoke control zone. This study established process of auto closing systems and analysis theory based on kinematics mechanism thesis and mechanism modelling of auto closing control units. And this study established engineering data construction and a source technology that can design each element of auto closing control units that choose closing force units through motion analysis simulation based on analysis theory. Therefore, it can give flexibility and elasticity of auto closing units development from this study. Also, it sees that can ready control means and technological countermeasure of smoke by development of auto closing units and secure high reliancity and stability of smoke control systems.

• Clinical and Experimental Pediatrics
• /
• v.48 no.2
• /
• pp.158-164
• /
• 2005

Purpose : We reviewed the therapeutic results of various Duct-Occlud coils(pfm AG, $K{\ddot{o}}ln$, Germany) to evaluate the efficacy of the most-recently modified Duct-Occlud coil(Nit-Occlud) in the transcatheter closure of patent ductus arteriosus(PDA), including large defects more than 4 mm in diameter. Methods : Two hundred and five patients who underwent percutaneous PDA occlusion using Duct-Occlud devices from March 1996 to December 2003 were enrolled and four types of Duct-Occlud [Standard(S), Reinforced(R), Reinforced reverse cone(RR) and Nit-Occlud(N)] were used in this study. The patients were followed up by echocardiogram and physical examination before discharge, one month, six months and 12 months after the procedure. Results : The rate of residual shunt according to the type of Duct-Occlud were as follows : S-54%, R-72%, RR-50%, N-14%(P<0.05 compared with other devices) at one month, S-25%, R-44%, RR-37%, N-0%(P<0.05 compared with other devices) at six months, S-8%, R-8%, RR-4%, N-0%(P<0.05 compared with S and R) at 12 months and later. Nit-Occlud coil showed the complete occlusion of PDA after six months of follow-up, even in 12 patients with relatively large PDA(>4 mm). Conclusion : The transcatheter closure of PDA using Duct-Occlud was an effective treatment and our study revealed that a Nit-Occlud coil which showed higher rate of occlusion even in PDA with large diameters over than 4 mm, was a more effective modality compared to previous devices.

• Information and Communications Magazine
• /
• v.30 no.10
• /
• pp.46-52
• /
• 2013

최근 기술 발전과 더불어 해양에서의 안전과 환경보호를 위해 선박에서의IT기술 특히 정보통신 기술과의 융합에 대한 중요성이 증가되고 있다. 특히, 국제해사기구에서 추진하고 있는 e-navigation은 조선 및 선박에 IT 융합의 새로운 패러다임을 제공하고 있다. 이를 위해, 선박에 디지털 및 전자장비들이 도입되고 있으며, 통신의 형태도 폐쇄적인 선박 통신 구조에서 개방형, 통합형 형태로 변화되어가고 있다. 본 고에서는 해양 안전을 위해 국제해사기구에서 추진하고 있는 e-navigation과 이를 실현하기 위한 조선-IT 융합 특히 선박에서의 통신과 관련된 기술동향에 대해서 살펴보았다. 특히, IEC와 ISO와 같은 국제 표준화 기구들의 역할과 최근 동향 및 향후 국제표준화 방향에 대해 정리하였다.

• Clinical and Experimental Pediatrics
• /
• v.52 no.4
• /
• pp.488-493
• /
• 2009

Purpose : The aim of this study was to assess the efficacy and safety of recent-generation patent ductus arteriosus (PDA) closure devices applied by a new selection strategy according to the characteristics of each PDA. Methods : From February 2003 to January 2006, 138 patients underwent transcatheter closure of PDA (study group). According to the size and morphology of each ductus, a COOK Detachable Coil or 'flex' PFM Nit-Occlud was used for a small ductus (group 1, n=43); 'medium' PFM Nit-Occlud (group 2, n=49) for a moderate ductus; and an Amplatzer Duct Occluder (group 3, n=46) for a large ductus. The 83 patients who underwent transcatheter closure of PDA from February 2000 to January 2003 were defined as the comparison group. The Qp/Qs ratio, pulmonary/aorta pressure ratio, and MD of the ductus were compared. Immediate and follow-up results including residual shunts and complications were also evaluated and compared among groups. Results : In all 138 patients, complete occlusions were confirmed without major complications, while procedure failure (n=2, 2.2%), device embolization (n=1, 1.1%), and persistent residual shunt (n=4, 4.5%) were documented in the comparison group. Total complication rates were lower in the study group than in the comparison group (study group, 1.4%; comparison group, 9.0%; P<0.05). Conclusion : A novel strategy adopting the merits of various recent-generation devices for transcatheter closure of PDA provides excellent clinical results with minimal risk.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.9 no.6
• /
• pp.24-29
• /
• 2001

Adaptive valve timing control is one of the promising techniques to accomplish the optimized mixture formation and combustion depending on the load and speed, which is needed to meet the future challenges in reducing fuel consumption and exhaust emissions. The behavior and the effect of adaptive valve timing control system has been investigated by computer simulation, which simulates the gas dynamics in engines. Improved fuel economy can be achieved by reduction of pumping loss under low and mid load conditions. EIVC(Early Intake Valve Closing) strategy turns out to be superior to LIVC(Late Intake Valve Closing) strategy in reducing fuel consumption. Deterioration of combustion quality can be overcome by introducing LIVO(Late Intake Valve Opening) strategy, which increases turbulent intensity in cylinders. Furthermore, LIVO can reduce HC emission by decreasing the required amount of fuel to be injected during cold start.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.30 no.10 s.253
• /
• pp.1293-1297
• /
• 2006

In this paper, kinematic analysis of a double-action link-type die set for enclosed die forging is carried out. The structure of the die set and its operational principle during enclosed die forging are introduced in detail. A closed-form solution of the relative velocity of the middle plate with respect to the upper plate after the upper and lower dies are enclosed is given in terms of the link lengths and the distance from the lower pin to the upper pin of the link system. The effect of the link lengths on both strokes and velocities is investigated. It has been shown that the relative velocity of the middle plate with respect to the upper plate varies almost linearly with the stroke of the upper plate.