• 한국항공운항학회:학술대회논문집
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• 2016.05a
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• pp.68-72
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• 2016

본 연구는 외국인 승무원의 팀 배속이 한국승무원과의 팀웍, 팀만족, 직무성과에 미치는 영향을 밝힘으로써 효율적인 외국인 승무원 관리방안을 모색하고 나아가 한국인 및 외국인 객실승무원의 단합된 팀웍으로 최상의 고객서비스를 제공하는 데 그 목적이 있다. 본 연구는 문헌연구와 실증연구를 바탕으로 진행하였으며 외국인 승무원의 팀 배속이 한국승무원과의 팀웍, 팀만족도, 직무성과에 미치는 영향 관계를 규명하였다. 설문은 K항공사 객실승무원을 대상으로 496부를 설문 조사하였으며 자료를 수집하고 분석한 결과, 외국인 승무원의 팀 배속이 한국승무원과의 팀웍, 팀만족, 직무성과에 긍정적인 영향을 미치는 것으로 나타났다.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.2
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• pp.101-103
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• 2006

최근 LNG 선박에 승무할 인력의 심각한 부족이 예상되고 있는 가운데, 국내는 물론 국외에서도 인력양성을 위한 교육훈련센터의 개설 등 활발한 움직임이 보이고 있다. 그러나 이러한 LNG 교육훈련센터에서는 독자적으로 개발한 교육훈련 프로그램에 입각하여 교육생을 모집하고 있으며, 따라서 세계적으로 통일된 높은 수준의 교육훈련을 기대하기 어려운 실정이다. 이 발표에서는 국제해사대학연합의 LNG 활동의 일환으로 추진된 아시아 LNG 교육훈련센터의 개요와 센터에서 개발된 표준 교육훈련 프로그램에 대하여 설명하고자 하며, 이러한 교육훈련과정이 향후 전세계 LNG 교육훈련의 표준을 정립하는데 초석이 되도록 노력하고자 한다.

• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.259-260
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• 2008

This paper presents fractional frequency reuse (FFR) with sub-channel borrowing to improve spectral efficiency of the wireless broadband (WiBro) system. FFR has constraints on usable sub-channels to balance the interference and cell capacity. Our FFR with sub-channel borrowing allows use of the dedicated sub-channels assigned to neighboring cells. Simulation results show that the proposed FFR with sub-channel borrowing improves the performance of the WiBro system.

• Journal of the Korean Society for Precision Engineering
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• v.22 no.8 s.173
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• pp.182-191
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• 2005

It is very important to obtain a high quality of bone image for an accurate ultrasonic measurement of bone mineral density. In this study, we suggested a technique to acquire an optimal image by adapting an acoustic lens and a properly selected ultrasonic probe. Also, we have applied an image processing algorithm with which automatically makes a decision of brightness and contrast of image by generating threshold level, a composition of ultrasonic data, an elimination of noise using modified median filter, and a real time interpolation. We could confirm much improved resolution of bone image with acoustic lens attached to the ultrasonic probe and with the image processing algorithm suggested in this study. Therefore, it became possible to precisely diagnose the osteoprosis using ultrasonic imaging technique.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.10a
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• pp.245-248
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• 1997

The distilled water is used for the ultrasonic wave propagating material in the measurements of broadband ultrasonic attenuation (BUA) that is applied in industrial and medical applications, The acoustic impedance of water is significantly changed with its temperature. Therefore, the quantitative evaluation of BUA with temperature and the ultrasonic wave propagating distance is highly needed. In this study, we evaluated the variation of attenuation with change in temperature. To measure the variation of BUA in the low frequency region at the temperatures, 27$^{\circ}C$, 29$^{\circ}C$, and 31$^{\circ}C$, we tested the Plyethylene, Teflon, MC-Nylon, Urethane specimens and analyzed the center frequency, frequency bandwidth, spectral peak amplitude. The results showed that BUA value appeared to be lower with increasing temperature. This may be due to the fact that the frequency feature of ultrasonic wave is affected by not only the specific gravity, acoustic impedence, but material crystalline, porosity, the distance of ultrasonic wave propagation in water.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.29 no.6 s.237
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• pp.787-794
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• 2005

Nowadays chronic degenerative diseases such as arthritis are increasing rapidly, even though acute infectious diseases are decreasing due to the advance of modern medicine. Although many of remedies are developed for arthritis healing, there is no precise medical prescription, and pathogenesis is not examined exactly. In this study, we confirmed gene expression of BMP 1A, BMP 2B, osteonectin and MGP which are genes related with bone formation in osteoblast by using ultrasonic stimulation. Through this study, we also evaluated the fact that ultrasound could be applied to arthritis healing by making activated osteoblast induce remodeling of cartilage. As a result of this research, BMP 2B and MGP have higher rates of expression in specific ultrasound mode. In conclusion, it is expected that ultrasound could be used efficiently for healing arthritis if we use ultrasounds according to symptoms of arthritis on reasonable terms.

• Journal of the Korean Operations Research and Management Science Society
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• v.27 no.4
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• pp.67-86
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• 2002

This paper considers subway crew scheduling problem. Crew scheduling is concerned with finding a minimum number of assignments of crews to a given timetable satisfying various restrictions. Traditionally, crew scheduling problem has been formulated as a set covering or set partitioning problem possessing exponentially many variables, but even the LP relaxation of the problem is hard to solve due to the exponential number of variables. In this paper. we propose two basic techniques that solve the subway crew scheduling problem in a reasonable time, though the optimality of the solution is not guaranteed. We develop an algorithm that solves the column-generation problem in polynomial time. In addition, the integrality of the solution is accomplished by variable-fixing technique. Computational result for a real instance is reported.

• Transactions of Materials Processing
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• v.17 no.4
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• pp.292-301
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• 2008

Type 2 compressed natural gas(CNG) storage vessels for automobiles are becoming widely used. They are not only supplied to automakers in Korea, such as Hyundai Motors, but increasingly, they are being exported overseas. Autofrettage is a process that produces beneficial residual stresses in a vessel by subjecting it to excessive internal pressure. This strengthens the vessel and improves its fatigue resistance. This paper presents research investigating the autoftettage process and residual stresses it produces in type 2 CNG storage vessels. A finite element analysis technique and a closed form equation are used. Then, fatigue resistance is analyzed through a fatigue evaluation performed according to ASME section VIII.

• Journal of the korean Society of Automotive Engineers
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• v.4 no.2
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• pp.47-57
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• 1982

Smoke, Hydrocarbon and Garbon Monoxide emissions of concern in environmental pollution on AVDS-170-2D diesel engine were studied experimentally and past studies on emissions of diesel engine were investigate. Engine speed and load were considered as variable factors influencing the emissions. The test results of a multicylinder, direct injection and turblcharged 4 cycle diesel engine were compared with past studies. Both emission levels of experimental study and past studies were markedly influenced by engine operation factors. The results obtained in this study can be summarized as follows; 1) Smoke intensity is proportional to engine load and varies with engine speed. 2) Hydrocarbon and nitric oxides emissions vary with engine speed and load. 3) Garbon monoxide emission is insensitive to engine speed and varies with engine load.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.22 no.3
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• pp.33-49
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• 2014

The object of this study is to verify the effects of job stress on burnout and job satisfaction of flight attendants and to confirm the difference in the effect on the consciousness of full service carrier and low cost carriers' flight attendants. In order to confirm, the study examines the relationship between job stress, burnout, and job satisfaction of airline cabin attendant. A survey was done for 55days from January 5th 2014 on flight attendants and total 200 valid samples were analysed. The results of the study demonstrated significant relationship and difference in job stress, burnout and job satisfaction of flight attendants between full service carrier and low cost carrier. As a result, the study is significant as it satisfaction between divergent airline work environment.