• 항공우주정책ㆍ법학회지
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• 제5권
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• pp.303-320
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• 1993

The construction of New Seoul International Airport is under way despite much controversy. Among much discussed, but not well-formulated controversy is the possibility of the airport as a hub in the North Asia Region. This paper specifies the factors which render it possible for an airport to be a regional hub. Then each factor is applied to the new airport to see whether it can function as a hub airport. Also examined is the qualitative cost and benefit calculation related to the hub function. The usual discussion has missed one big point of cost side of hub function in the belief that the hub only produces benefits to the national economy where the airline and airport industry belong; earlier-than-expected congestion and the necessity to expand the airport sufficiently enough to accommodate the increasing air demand. An airport as a hub is determined by several factors; geographical location ; economic status of the country where the airport belongs ; bilateral air service agreements according to which the airlines can exercise the route rights; the airport charges which directly influence the cost structure of the carriers ; international aviation and airport related policies of each country in the region ; airport capacity etc. The tentative implications of this paper are the followings; first, the new airport is able to function as a regional hub in the transpacific routes which connect Asian countries and North America. That is, directional hubbing by the airlines is implicated; second, the main benefits may be accrued to american airlines exercising all the route rights in the Asian region; third, the governmental effort to make the new airport a regional hub must take caution in optimizing the hubbing level (% of transitting passengers and freight) between the benefits and the costs. Further Studies may include optimal level of hubbing for the new airport and, quantification of the impact of the new airport on the national economy depending on the degree of hubbing.

• 소성∙가공
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• 제21권7호
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• pp.453-458
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• 2012

The flange hub is a main component of an automotive steering system. Dimensional precision of the flange hub is very important for precise control of the steering force. Consequently, the process design for precision forming of a flange hub is required. The teeth of the flange hub are generally formed by bending. In this study, the formability of flange bending was investigated using FE simulations. For the optimum process conditions, the flange is bent by movement of an insert die, and the die angle and bending length are selected as $90^{\circ}$ and 4mm respectively.

• 한국항만경제학회지
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• 제20권1호
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• pp.21-42
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• 2004

This paper addresses the operation, problems, and development policy of Gwangyang Port, Korea. This paper aims to analyze the operation condition and problems of Gwangyang Port and suggest long-term policies for developing Gwangyang Port as a logistic hub in northeast period. It is made up of three main sections: the operation, problems, and forecast of freight volumes; analysis of operational results of Gwangyang Port; development strategies of Gwangyang Port as a Logistics Hub. This paper was mainly based on a review of current papers/reports, an analysis of secondary data, and questionnaire survey. The major development strategies identified consisted of expansion regular service sea-route, formation of inter-modal transportation system, strengthening of port sales for Gwangyang port's recognition, securing operation-profits by fixed cargo volume, and promotion of free tread zone.

• Industrial Engineering and Management Systems
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• 제9권2호
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• pp.88-96
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• 2010

This paper presents a two-phase quantitative framework to aid the decision making process for effective selection of an efficient freight logistics hub from 8 alternatives in Thailand on the North-South economic corridor. Phase 1 employs both multiple regression and Pearson Feature selection to find the important criteria, as defined by logistics hub score, and to reduce number of criteria by eliminating the less important criteria. The result of Pearson Feature selection indicated that only 5 of 15 criteria affected the logistics hub score. Moreover, Genetic Algorithm (GA) was constructed from original 15 criteria data set to find the relationship between logistics criteria and freight logistics hub score. As a result, the statistical tools are provided the same 5 important criteria, affecting logistics hub score from GA, and data mining tool. Phase 2 performs the fuzzy stochastic AHP analysis with the five important criteria. This approach could help to gain insight into how the imprecision in judgment ratios may affect their alternatives toward the best solution and how the best alternative may be identified with certain confidence. The main objective of the paper is to find the best alternative for selecting freight logistics hub under proper criteria. The experimental results show that by using this approach, Chiang Mai province is the best place with the confidence interval 95%.

• 소성∙가공
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• 제21권7호
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• pp.397-402
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• 2012

The flange hub is a main component in an automotive steering system. In general, the flange hub are fabricated by mechanical machining, which is a process where material waste is inevitable. It is well-known that a net-shape cold forging cannot only reduce material waste but can also improve the mechanical strength of the final product. Thus, a forging process design was conducted for production of a flange hub. Significant spring-back occurs around the flange due to its small thickness in conjunction with the residual stresses after forging. In order to achieve the required dimensional accuracy, a process design with appropriate spring-back control is needed. In this study, a modification of the forging die was designed based on FE analysis with the purpose of spring-back compensation. Four kinds of different die designs were evaluated and the optimum design has two times less spring-back than the initial design. The compensation angle of the optimum design is 0.5 degrees. The results have been experimentally confirmed by cold forging of a flange hub and comparing the amount of spring-back between the actual component and the FE analysis.

• 한국유체기계학회 논문집
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• 제14권3호
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• pp.59-64
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• 2011

Wind turbine frame will be required to be longer, lighter, more reliable and more consistent. Therefore it is necessary to lose weight of the wind turbine hub. Light-weight Design of a wind turbine is required to be at least 20 years. Therefore, this paper investigates the development for wind turbine rotor hub using design of topology optimization. The model is a pitch regulated wind turbine with three rotor blades where the main frame is made of nodular iron. For optimization, calculating stresses based on displacements and based on these data to carry out a verification of static and fatigue strength carried out. For this verification, two kind of analysis is used. One is static analysis and the other is fatigue analysis. Then the rotor hub of wind turbine frame is optimized using topology method.

• 한국항공운항학회지
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• 제20권4호
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• pp.50-56
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• 2012

Rotor system is a very important part which produce lift, thrust and control force in helicopter. Component of rotor system must have structural integrity for applied load. The estimation of structural integrity is regarded greatly as important in aerospace field. In this study, the process of structural analysis performed for bearingless main rotor system of helicopter. The composite flexbeam and torque tube of bearingless main rotor are very thick, so 3D layered soild elements of MSC.PATRAN were used to get the finite element analysis results. To estimate structural integrity, non-linear static analysis considering geometric non-linearity is performed. In addition, detailed finete element analysis and non-linear static analysis are performed to consider the stress concentration for fitting effect and contact surface. The estimation process of structural integrity for bearingless main rotor system of helicopter may help the design.

• 한국항공운항학회지
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• 제23권2호
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• pp.40-50
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• 2015

This study deals with transfer passengers in hub airports. The research objective is to derive measures for transfer passenger quantity enhancement at Incheon International Airport by applying Analytic Hierarchy Process. In pursuing the above objective, this study conducted a survey to evaluate various selection criteria for choosing transfer airports and ranked attributes in weight order with Analytic Hierarchy Process. Furthermore, based on the trend analysis of Incheon International Airport's transfer passenger movement, this paper analysed main transit routes of Incheon International Airports against competitor airports among the region. The main result found from the study is flight frequency, ticket price and connecting hour were the most important 3 factors when people choose transit airports. Therefore, it is recommended government, airport authority and airlines to cooperate closely to meet the transfer passengers' needs on frequency, price and transit hour of flights.

• 한국항만경제학회지
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• 제29권2호
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• pp.39-61
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• 2013

동북아 지역내 경제성장을 끌고 나가는 중국은 해운항만 분야에서는 환적화물의 흐름과 초대형 선박들의 기항지 선택 및 선사들의 네트워크 구축에 대한 영향을 통하여 동북아 단일 시장의 통합을 선도하고 있으며, 지역내 주요 항만들에 다양한 영향을 주고 있다. 이 연구는 중국 주요 항만-상해항, 천진항, 홍콩항 포함-들의 개발과정과 항만들간 개발의 상호관계를 시계열적으로 고찰함으로써 중국 항만의 미래를 조망하는 데에 유익한 시사점을 도출하는 데에 초점을 두고 있다. 주요 항만의 개발과정과 특성은 다음과 같다. 홍콩항은 고베항의 터미널을 세분화 전략보다는 물동량의 증가 추이에 따라 단계적으로 시설을 대형화하는 전략을 취하면서 운영의 안정성을 추구하였다. 상해항은 물동량의 지속적 증가에도 불구하고 2000년대 초까지 확장에 보수적 태도를 견지하였으며, 컨테이너 부두시설을 집중화하여 시설 대형화의 장점을 취하고 있다. 천진항도 타 중국항만과 유사하게 물동량의 증가에 따라 단계적 부두 확충과 부두시설의 집중과 특화 전략을 취하고 있다. 중국 거점항만들에 대한 패널자료와 패널회귀분석은 이들 항만들이 각기 독자적 수요기반을 갖고 있음을 시사하고 있으며, 항만들간 상관관계가 1980년대에는 낮았지만, 1990년대 이후 점차적으로 동시적 상관관계가 높아지는 것을 나타냈다.

• 한국항만학회지
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• 제13권1호
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• pp.11-26
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• 1999

The subject of port efficiency is one of the important issues facing port authorities and policy makers today. A number of studies have been undertaken which compare ports in terms of their efficiency. But any port comparison can only be valid and meaningful if a port’s efficiency is compared with a similar port. The main objective of this paper is to introduce a systematic approach to identifying similar ports based on the technique of principal component analysis and cluster analysis. And it seeks to identify the most important factors underlying the port classification. Lack of awareness of which factors differentiate ports has resulted in an unnecessary collection of data which are of limited use in port classification. This paper has identified five groupings of similar ports within which port comparision can be justifiably made. This approach can be used for any future port comparision.