• Journal of Aerospace System Engineering
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• v.16 no.3
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• pp.35-41
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• 2022

UAM (Urban Air Mobility) is a new safe, secure, and more sustainable air transportation system for passengers and cargo in urban environments. Commercial operations of UAM are expected to start in 2025. Since production rates of UAM are expected to be closer to cars than conventional aircraft, the airworthiness methodology for UAM must be prepared for mass production. Composite materials are expected to be mainly used for UAM structures to reduce weight. In this paper, the composite material qualification method was derived and the materials were applied for small aircraft application. It is expected to reduce the airworthiness certification time by applying composite material qualification system and its database.

• The Korean Journal of Air & Space Law and Policy
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• v.26 no.1
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• pp.93-125
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• 2011

The International Civil Aviation Convention (Chicago Convention) has been a backbone of international air transport system whereby air transport between States should be based on bilateral agreements, and in particular, international airfares, which are set up through IATA(International Air Transport Association) rate-fixing machinery could be approved by the governments concerned. International airfares are fares for transporting passenger and freight and their conditions between two or more countries. However, since U.S. pursued th deregulation policy in 1978 whereby routes, capacity and fares could be freely determined by airlines, many States have been following so called open-skies agreements. In many cases, aeronautical and competent authorities have been reviewing whether airlines' commercial activities including air fares could possibly conflict with free competition rules envisaged in relevant laws and regulations. As competition among airlines gets intense, airlines often resort to cooperation with other airlines in the forms such as equity exchange, M&A, code-sharing, fares consultation and resource pooling, mainly with a view to effectively use resources available and to avoid monopoly situation resulting from excessive and destructive competition among players. Whereas bearing in mind that application of competition laws is important to secure consumers' interests by preventing airlines's malpractices such as bargaining exorbitant fares, it is also important to comprehensively consider as many factors as possible, from that unilateral measure by governments may bring about retaliatory measures by the governments affected, to that airlines' cooperative practices may rather increase consumers' benefits by lowering air fares.

• Journal of the Korean Society of Marine Environment & Safety
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• v.28 no.6
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• pp.946-954
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• 2022

More than half of barges have been surveyed and designated as an "unmanned barge". The main advantage of the unmanned barge is that it can carry more cargo equivalent to 25 percent of freeboard compared to that of a manned barge. In contrast, it needs an onboard crew barge because the bargeman is in charge of several tasks during sailing such as mooring or unmooring barges to or from a wharf, dropping and heaving up an anchor and turning on and of navigational lights and shapes. The instant recognition is that a tug assume the responsibility of operating a barge; however, different situations exist in which the shipper, as the operator of the barge, hires a tug. Although a tug might be a carrier of a barge under a specific contract, the master of the tug should fulfill his duty to complete its voyage. Most masters are not provided with the particulars of a barge and the information regarding the bargemen onboard, which is believed not to respect the master's authority and lead to an unintended violation of relevant laws. This paper presents three recommendations for resolving these issues: the policy approach for changing unmanned barges to manned barges, issuing a minimum safe manning certificate, and providing the master of tug information on the barge and the crew onboard. Thus, the proposed approach can be expected to improve the crew's working conditions, diminish the violation of the maximum number of persons onboard the barge, and ensure the authority of the master of tug through such recommendations.

• Journal of Korean Society of Transportation
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• v.15 no.3
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• pp.75-92
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• 1997

추월가능성을 판단하기 위해서 앞을 바라볼 수 있어야 하는 거리를 추월시거라 한다. 적절한 추원시거의 확보는 2차선 도로의 효율성과 운전자의 안전성 제고 및 도로설계시 매우 중요하다. 이러한 목적을 위하여 추월시거를 산정할 수 있는 여러 모형이 개발되었으나, 실제 교통상황을 반영하기에 많은 문제점을 안고 있음이 지적되고 있다. 따라서 본 논문은 기존 모형들의 이론적 배경을 고찰하고, 각 모형의 단점과 한계를 파악하여, 운전자의 실제 추월형태를 고려한 새로운 추월시거산정모형을 개발하는데 주안점을 두고 있다. 본 논문에서 개발한 PASS모형은 현재 미국에서 도로설계시 기준으로 사용되고 있는 AASHTO모형을 보완하여 구축하였다. 기존의 모형들은 서로 다른 조건을 가정하여 개발되었기 때문에 각 모형들의 추월시거 산정값을 비교분석하는데 어려움이 있다. 하지만 PASS모형은 운전자의 반응시간, 차량의 길이, 차량의 가속능력 등 실제 추월시거 산정시 반드시 고려해야 할 중요한 요소들을 특성치로 반영할 수 있게 함으로써 다양한 추월 상황과 현실적인 교통상황을 폭넓게 수용할 수 있는 장점을 갖고 있다. 본 논문에서는 새로 개발한 P SS모형을 이용하여 얻은 결과와 기존의 AASHTO모형, MUTCD모형, Glennon모형을 통해 얻은 결과를 비교하였으며, PASS모형에 우리나라 현실에 적합한 특성치를 적용하여 2차로 도로의 추월시거를 산정하였다. 이 결과 현재 우리나라 도로용량편람에서 제시하고 있는 추월기능구간 기준인 450m가 설계속도가 낮은 일반국도에는 타당함을 확인할수 있었다. 그러나, 설계속도가 높은 화물타의 운행빈도가 높은 고속국도의 경우, 재검토가 필요할 것으로 판단된다.기존의 광유계 윤활제에 비하여 대단히 고가하는 문제점을 갖고 있다. 그러나 윤활 마찰면의 다양화와 가혹한 사용조건은 자성유체 윤활제의 연구개발 필요성을 크게 증대시키고 있다.xed Effects Model)을 결정하고, 각각에 해당하는 통계모형을 구축하였다. 이 결과 (1) 업종 및 기업규모별로 그룹간에 유의한 특성이 발견되었으며, (2) R&D 및 광고투자는 기업의 시장성과를 설명하는 중요한 변수이나, (3) R&D 투자의 경우는 광고에 비해 불확실성이 존재하는 것으로 나타났고, (4) 수리모형에서 도출된 한계원리가 통계모형에서도 유효한 것으로 드러났다.등을 토대로 한 10대 산업을 육성하기 위하여 과학기술부는 기술수요조사를 바탕으로 49개 주요기술을 도출하여, 과학기술 일류 국가 실현, 국민소득 2만불 달성이라는 국가적 슬로건을 내걸고 “차세대 성장동력” 창출을 위한 범정부차원의 기획과 연구비의 집중투자를 추진하고 있다.달성하기 위해서는 종합류류 전산망의 시급한 구축과 함께 화물차의 적재율을 높이고 공차율을 낮출 수 있는 운송체계의 수립이 필요한 것으로 판단된다. 그라나 이러한 화물전용차선의 효과는 단기적인 치유책일 수밖에 없기 때문에 물류유통 시설의 확충을 위한 사회간접자본의 구축을 서둘러 시행하여야 할 것이다.으로 처리한 Machine oil, Phenthoate EC 및 Trichlorfon WP는 비교적 약효가 낮았다.>$^{\circ}$E/$\leq$30$^{\circ}$NW 단열군이 연구지역 내에서 지하수 유동성이 가장 높은 단열군으로 추정된다. 이러한 사실은 3개 시추공을 대상으로 실시한 시추공 내 물리검층과

• Journal of Korea Port Economic Association
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• v.30 no.3
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• pp.209-230
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• 2014

The purpose of this study is to have a main change of korea logistics industry analysis and take in the whole situation and the characteristics about a logistics firms. In korean logistics industry, The rate of a carriage is among the low-level as compared with the increasingly high prices for diesel. besides, a national logistics cost and the sales in the transportation industry has increased steadily. On the other hand, the number of trucks and transfer companies has decreased steadily. This change is attributed to expansion of logistics firm size through the limit on a raise in the number of trucks and introduction of a direct consignment system. But medium and small logistics firm size is dwindling in numbers. In the meantime, 2PL since early 2000s has rapidly rose as powerful players in logistics industry by a strong Support of the parent companies. Government and academia have long noted the limit and problems of 2PL system and emphasize on the necessity of activating the 3PL system. So this study divided broadly into two groups that the primary characteristics of korea logistics industry are 2PL and 3PL. Through the results of this study, the management and financial perspectives mean that there is a considerable difference between 2PL and 3PL.

• Journal of Navigation and Port Research
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• v.39 no.1
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• pp.45-53
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• 2015

These days Container Terminals are focusing on increasing the quantity of containers and shipping lines choose Terminals by referring to the key elements of a terminal to perform the overall operation the fastest such as the location of the terminal, discharging ability, keeping environment, and other elements related to shipping in general. Container terminal is able to offer On-Dock service has become an important factor for shipping lines to choose that terminal. In this paper, we propose an algorithm for On-Dock system work algorithm, the algorithm Empty container exports, Full Container algorithm and The aim of our study focus on both container's gate out time and search for the effective terminal operation which is using the general On-Dock system through several algorithm like container batch priority, gate in and out job priority and empty container yard equipment allocation rule based on the automatic allocation method and manual allocation scheme for container. Gathering these information, it gives the priority and yard location of gate-out containers to control. That is, by selecting an optimum algorithm container, container terminals Empty reduces the container taken out time, it is possible to minimize unnecessary re-handling of the yard container can be enhanced with respect to the efficiency of the equipment. Operations and operating results of the Non On-Dock and On-Dock system is operated by the out work operations (scenarios) forms that are operating in the real Gwangyang Container Terminal derived results. Gwangyang Container terminal and apply the On-Dock system, Non On-Dock can be taken out this time, about 5 minutes more quickly when applying the system. when managing export orders for berths where On-Dock service is needed, ball containers are allocated and for import cargoes, D/O is managed and after carryout, return management, container damage, cleaning, fixing and controlling services are supported hence the berth service can be strengthened and container terminal business can grow.