• Journal of Pharmaceutical Investigation
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• v.22 no.3
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• pp.237-240
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• 1992

A series of biodegradable block copolymers consisting of $poly({\gamma}-benzyl\;L-glutamate)$ (PBLG) and poly(ethylene oxide) (PEO)-lactoselactone were prepared by polymerization of PEO-lactoselactone and ${\gamma}-benzyl$ L-glutamate-N-carboxyanhydride and characterized by IR and NMR. From circular dichroism measurements, it was found that the polymers exist in the ${\alpha}-helical$ conformation. Block copolymer microspheres were prepared by solvent-extraction-precipitation method for their primary evaluation for medical and biological applications.

• Proceedings of the KIEE Conference
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• 2001.11b
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• pp.296-298
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• 2001

This paper represents protective management system for transmission line involving the UPFC(Unified Power Flow Controller) device, which is the most vigorous component of FACTS. The presence of the UPFC significantly affects the line parameters of transmission system, which are also influenced by the distance relay setting. Moreover, depending on the UPFC location and its parameters, zones of setting the distance relay will be changed. Therefore, established protective system should be taken into account the variable injected voltage of the UPFC and constructed data base system.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2007.10a
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• pp.70-73
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• 2007

The forming characteristics of cup-rod combined extrusion process were investigated with process parameter change. Simultaneous forward rod extrusion and backward cup extrusion was conducted with magnesium alloy, AZ31B. Process parameters such as forward extrusion ratio, backward extrusion ratio, and working temperature were controlled in a specific region and the effects of the parameter change were examined. Surface crack was developed in a certain state of the process parameters combination. The crack-free forming limit of the alloy in the combined process was disclosed by the parameter study. The microstructures of the initial and extruded workpieces were observed.

• The KSFM Journal of Fluid Machinery
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• v.9 no.4 s.37
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• pp.13-19
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• 2006

For axial-type turbines which operate at partial admission, a performance prediction model is developed. In this study, losses generated within the turbine are classified to windage loss, expansion loss and mixing loss. The developed loss model is compared with experimental results. Particularly, if a turbine operates at a very low partial admission rate, a circular-type nozzle is more efficient than a rectangular-type nozzle. For this case, a performance prediction model is developed and an experiment is conducted with the circular-type nozzle. The predicted result is compared with the measured performance, and the developed model quite well agrees with the experimental results. So the developed model could be applied to predict the performance of axial-type turbines which operate at various partial admission rates or with different nozzle shape.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2014.10a
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• pp.142-143
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• 2014

해양사고의 원인을 파악하기 위해 해양사고 관련자의 특성(연령별, 해기면허별)을 분석해보면, 상급 항해사가 관련된 사고는 33.5%이며, 하급 항해사가 관련된 사고는 64.1%로 항해사의 급수별로 해양사고 관련 비율에 차이가 있으며, 특히 하급 항해사가 관련된 해양사고의 비율이 상급 항해사와 비교할 때 상대적으로 높았다. 이러한 하급해기사 면허 소자자의 경우 그 동안 상급 해기사 면허 소지자에 비해 해기교육을 이수할 기회가 적었으므로, 기초적인 부분에 대한 교육이 먼저 이루어져아 할 것으로 판단된다. 그러므로, 이러한 기초적인 부분에 대한 교육을 수행할 수 있는 사무실 환경에 보급이 가능한 보급형 시뮬레이션 시스템 개발이 필요하다. 이에, 하급 항해사의 과실에 의해 발생되는 사고를 줄일 수 있도록 비교적 영세한 해운업체에도 보급이 가능한 하급 해기사 평가용 시뮬레이션 시스템을 개발하였다.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2018.11a
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• pp.343-345
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• 2018

한국형 e-Navigation 중 SV20은 국적선 중 여객선(연안/국제) 및 서비스 요청 선박을 대상으로 선내시스템 원격모니터링 서비스를 제공하여 해상 관련 정보를 실시간으로 수집하고 분석하여 해상에서 선박의 안전을 증진하기 위해 개발 중인 시스템이다. 이러한 SV20 시스템을 모든 서비스 대상 선박에 적용하기 위해서 범용화가 필요하다. 그러나 선박마다 선형, 조종성능, 각종 장비 등의 차이점이 많아 범용화가 쉽게 이루어지지 않고 있다. 본 연구에서는 현재까지 진행 중인 한국형 e-Navigation 서비스 대상 선박의 사례 연구를 통해 선박이 가지는 특성을 비교하고 분류하여, SV20 항행안전모듈 범용화 방안을 제시한다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2017.05a
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• pp.394-396
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• 2017

In various types of UAV systems, which have been developed recently, the communication system that is responsible for the connection between the ground control unit and the UAV is called the data link.Especially, in the data link used in systems for transmission of surveillance images from UAV in real time, stability of communication should be ensured. In this paper, the design of the data link modem was proposed for the purpose of applying for UAV for surveillance. And, the designed wad verified through the performance measurement of the implemented systems.

• Journal of the Korean Society of Propulsion Engineers
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• v.13 no.6
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• pp.24-33
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• 2009

The present study deals with the optimization of the leading edge shape around a wing-body junction to minimize the strength of the horseshoe vortex, which is one of the main factor generating the secondary flow losses. For this purpose, approximate optimization method is used for the optimization. The study is performed by using $FLUENT^{TM}$ and $iSIGHT^{TM}$. The total pressure coefficient for the optimized model was decreased about 9.79% compared with the baseline model.

• Proceedings of KOSOMES biannual meeting
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• 2017.04a
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• pp.89-89
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• 2017

해양경찰 소형 경비정에 주로 장착되었던 물분사(water jet type) propeller가 중대형 경비함으로 점차 확대되고 있으며, 축 형식은 2~4축, 유동을 제어하는 bucket 유형도 DRB, CSU(SRB) 방식으로 나뉘어져 있다. 그러나, W/Jet 추진기 고유의 운동 특성이 반영된 조함법의 연구가 부족한 편이다. 여기서는 함정에 장착된 W/Jet 유형별 SHS를 통하여 직접 구현해 보고, SHS 구현이 현실적으로 어려운 함정은 해양경찰 함정장들의 면담을 통하여 습득한 것을 이론적으로 구현 제시하여, 함정 조함시 지식적인 인적오류를 최소화하여 W/jet 추진기가 장착된 함정 승조원의 조함 능력 향상 및 안전운항에 기여하고자 한다.

• Proceedings of the KSME Conference
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• 2004.04a
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• pp.1732-1737
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• 2004

In this paper, a small supersonic wind tunnel is designed and built to study the flow characteristics of a supersonic impulse turbine cascade. The flow is visualized by means of a single pass Schlieren system. The supersonic cascade with 3-dimensional supersonic nozzle was tested over a wide range of nozzle installation angle. Highly complicated flow patterns including shocks, nozzle-cascade interaction and shock boundary layer interactions are observed.