• Communications for Statistical Applications and Methods
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• 제18권2호
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• pp.257-266
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• 2011

The rapid development of airlines, has made airports busier and more complicated. The assignment of scheduled to available gates is a major issue for daily airline operations. We consider the over-constrained airport gate assignment problem(AGAP) where the number of flights exceeds the number of available gates, and where the objectives are to minimize the number of ungated flights and the total walking distance or connection times. The procedures used in this project are to create a mathematical model formulation to identify decision variables to identify, constraints and objective functions. In addition, we will consider in the AGAP the size of each gate in the terminal and also the towing process for the aircraft. We will use a greedy algorithm to solve the problem. The greedy algorithm minimizes ungated flights while providing initial feasible solutions that allow flexibility in seeking good solutions, especially in case when flight schedules are dense in time. Experiments conducts give good results.

• 한국융합학회논문지
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• 제10권8호
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• pp.165-170
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• 2019

2018년 국토교통부의 통계에 따르면, 연평균 항공교통이용자만 국내선 5.07%, 국제선 8.84%가 증가하였다. 한류의 열풍으로 인해 지속적인 외국인 관광객의 수요가 증가하고 있다. 동시에 개인의 삶의 질을 중요시하는 새로운 생활 문화가 자리잡아가고 있으며 이와 더불어 저가 항공사의 출현으로 인해 내국인의 해외 관광 또한 증가하고 있다. 따라서 효율적이고 정확한 항공 수요예측을 진행하여 체계적인 공항 인프라를 조성하는 것이 중요하다. 본 연구에서는 빅 데이터(big data)를 기반으로 하여 도심권 공항의 국내선 및 국제선 장기 수요예측을 진행하였다. 국내선의 경우 2028년 이후 인구 감소에 따라 공항이용객이 다소 감소할 것이며, 국제선은 GDP증가에 따라 지속적으로 증가할 전망이다. 따라서 미래의 항공수요에 대처하기 위해서는 국내 공항의 여객터미널 개선 및 확충이 절실하다.

• 농촌의학ㆍ지역보건
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• 제27권1호
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• pp.115-123
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• 2002

1997년 1월 1일부터 2001년 12월 31일까지 5년간 울릉군 보건의료원 응급실을 내원하여 헬리콥터를 이용하여 육지병원으로 후송된 환자를 조사하였다. 헬리콥터가 운행된 회수는 5년간 88회, 후송된 환자들은 110명으로 113건이었다. 헬리콥터의 연도별 운행 회수는 1997년은 13회(14.8%), 1998년에는 17회(19.3%), 1999년에는 18회(20.5%), 2000년에는 17회(19.3%), 2001년에는 23회(26.1%) 운행하여 연도에 따라 헬리콥터 운행 회수가 증가하는 경향을 보였다. 헬리콥터 종류는 해양경찰 헬리콥터가 46회(52.3%), 119 소방 헬리콥터가 19회(21.6%), 해군 헬리콥터는 14회(15.9%), 민간 헬리콥터가 7회(8.0%) 운행하였다. 후송 시간대는 오전 6시부터 오후 6시 이전까지 79회(89.8%)가 후송되었다. 후송 환자의 계절별 분포는 가을에 25회(28.5%), 봄에 23회(26.2%) 운행하였다. 최종 후송 지역은 경상북도 포항시 47건(43.1%), 강원도 강릉시 34건(31.2%), 대구광역시 16건(14.7%) 서울 10건(8.8%) 등의 순이었다. 후송 환자의 성별 분포는 남자가 71건(65.1%), 여자가 38건(34.9%)으로 남자가 많았다. 연령별 분포는 60세 이상이 31건(28.4%), 30대가 20건(18.3%), 40대가 16건(14.7%) 등의 순이었다. 진료과별 분포는 신경외과 42건(37.1%), 내과 21건(18.6%), 일반외과와 정형외과가 각각 13건(11.5%) 등의 순이었다. 질병별 분포는 뇌졸중이 27건(23.9%)으로 가장 많았으며, 골절이 13건(11.5%), 두부손상 11건(9.7%), 임신과 관련된 출혈 및 통증 10건(8.8%), 복막염 8건(7.1%) 등의 순이었다. 한국표준질병사인분류(3-KSCD)에 의한 분포는 순환기계의 질환(IX)이34건(30.1%), 손상, 중독및기타(XIX)가34건(30.1%), 소화기계질환(XI)이 23건(20.4%) 등의순이었다. 울릉도를 비롯한 도서지역의 응급환자 후송에는 헬리콥터의 이용이 필수적이다. 보다 효율적인 응급환자 후송을 위해서는 헬리콥터의 야간 운행, 헬리콥터 내의 환자감시장치 등의 의료장비의 확보, 공식적인 응급후송용 헬리콥터의 확보 및 이를 위한 법 제정 등이 이루어져야 할 것이다.

• 한국항공운항학회지
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• 제26권2호
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• pp.123-131
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• 2018

Air transport industry tries to enhance punctuality, stability and amenity for customer's satisfaction. Especially airlines and airports do make an effort as the distance between these two stakeholders and passengers are close. This research has empirically discussed the relationship between duty free shop purchase of passengers and the number of flights and hours of schedule delay at the airport. According to the result, the total sales of duty free shop sales have meaningful influence on the number of flights and hours of delay. In order to decrease such an impact, close cooperation between airports and duty free shops required.

• 한국항공운항학회지
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• 제26권4호
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• pp.13-19
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• 2018

Master plan plans for new airports should estimate the approximate scale of the airside's moorings and terminals. The size of the pavilion can be determined by complex factors such as the operating hours of the operating company, the frequency of operation, and the aircraft class. Among them, the number of flights is calculated using the Horon-jeff equation because of the relationship between the number of flights and the time occupied by the mains. Since this estimation formula is a simplified formula, it is necessary to verify the appropriateness of the method of estimating the scale and to suggest improvement directions. Therefore, in this study, we propose a method of estimating the size of the western flags by investigating and analyzing the main airports of overseas airports to determine whether the application of the Horon-jeff formula is appropriate.

• 한국정밀공학회지
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• 제20권8호
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• pp.185-193
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• 2003

The modular self-wiping co-rotating twin screw extruder (SWCOR) has become the most important of twin screw machines. Screw design is one of the most important factors in determining performance of screw extruder. The screw flight and screw channel geometry of SWCOR is determined by the screw diameter, centerline distance, helix angle, and flights number. The maximum allowable throughput rate on a twin screw extruder is determined by a combination of free volume and available specific torque. In this paper we designed geometrical parameters of extruder screw and presented optimal specific torque value in K=1.55, and then developed screw design program for the screw cutting by the use of JAVA API in the twin screw extruder.

• 대한기계학회논문집B
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• 제21권12호
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• pp.1615-1623
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• 1997

Numerical study on the chaotic stirring of the screw extruder model proposed has been performed. The velocity field was used in obtaining the trajectories of passive particles for studying the stirring effect of the screw extruder. Two nonlinear dynamical tools, that are Poincare sections and Lyapunov exponents, were used in analysing the stirring effect. The Poincare sections and the Lyapunov exponents show that the stirring effect is most satisfactory, when n(the number of flights in a section) is 1, for the case a (aspect ratio ; flight height divided by the spacing between flights) being O.1. It is also required to set n=3, or 5 at a= 0.2, 0.3 for a uniform stirring.

• 경영과학
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• 제30권1호
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• pp.1-14
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• 2013

We conduct the future studies suggested by Park and Seo [3]. They considered a seat inventory control problem in which flights depart sequentially during a similar time-interval and passengers purchase available seats depending on individual customer choice behavior. Customer choice behavior can lead to one among a horizontal shift, a diversion-up, and a booking loss when a desired fare class is unavailable. We investigate how seat availability calculation method, booking limit control mechanism, seat inventory capacity, number of booking class, type of seat demand influence on revenues in an airline industry through thorough computer simulation experiments.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2008년 영문 학술대회
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• pp.480-485
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• 2008

In this study, two types of ramjet intake were designed for the flight condition of Mach number 2 and 5 and numerical analysis was performed. In order to widen the flight envelope range(Mach number $2{\sim}6$), movable intake concept was applied. The central body was designed so that the capture area ratio which is one of most important factors of ramjet intake design could be adjusted. And various types of cowl and movable insert part of shell were designed in order to control throat area which could increase total pressure recovery. The numerical results showed that the designed ramjet intake could be applied in various flights Mach number.

• Clinics in Shoulder and Elbow
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• 제26권4호
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• pp.416-422
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• 2023

Background: Advancements in airport screening measures in response to 9/11 have resulted in increased false alarm rates for patients with orthopedic and metal implants. With the implementation of millimeter-wave scanning technology, it is important to assess the changes in airport screening experiences of patients who underwent total shoulder arthroplasty (TSA). Methods: Here, 197 patients with prior anatomic and reverse TSA completed between 2013 and 2020 responded to a questionnaire regarding their experiences with airport travel screening after their operation. Of these patients, 86 (44%) stated that they had traveled by plane, while 111 (56%) had not. The questionnaire addressed several measures including the number of domestic and international flights following the operation, number of false alarm screenings by the millimeter-wave scanner, patient body habitus, and presence of additional metal implants. Results: A total of 53 patients (62%) responded "yes" to false screening alarms due to shoulder arthroplasty. The odds of a false screening alarm for patients with other metal implants was 5.87 times that of a false screening alarm for patients with no other metal implants (P<0.1). Of a reported 662 flights, 303 (45.8%) resulted in false screening alarms. Greater body mass index was not significantly lower in patients who experienced false screening alarms (P=0.30). Conclusions: Patients with anatomic and reverse TSA trigger false alarms with millimeter-wave scanners during airport screening at rates consistent with prior reports following 9/11. Patient education on the possibility of false alarms during airport screening is important until improvements in implant identification are made. Level of evidence: IV.