• Journal of Navigation and Port Research
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• v.39 no.6
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• pp.515-521
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• 2015

The purpose of this study was to analyze the weights of obstacle factors against mutual access of towed trailers of car-ferry between South Korea and China using Fuzzy-AHP. To this end, factors were first selected through literature research and finally selected through in-depth interviews with a group of experts in cargoes who are currently in car-ferry companies. Selected high rank obstacle factors included unstable service provision, limited policy support, and additional costs being incurred and among them, unstable service provision was identified as the most serious obstacle factor through analysis. Eleven measurement variables selected include insufficient supply of container yard, trailer insurance and management issues, insufficient special equipment, insufficient specialized manpower, limited input service courses, insufficient marketing and public relations strategies, and increasing transportation costs and among them, increasing equipment returning costs due to unbalanced cargo gathering were identified as the most serious obstacle factor through analysis followed by limited input service courses, insufficient special equipment, delays in procedures, and occurrence of additional procedures in order of precedence.

• Journal of the Korean Geotechnical Society
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• v.29 no.11
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• pp.49-60
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• 2013

The plan for major design-build projects of railway link among countries in gulf area (GCC) and freight rail construction is recently announced, but Korean companies have a hard time tendering due to special geotechnical condition in the Middle East. The major geotechnical risks during railway construction in the Middle East are related to ground improvement of soft Sabkha ground, wind-blown sand mitigation measure, dune sand compaction, and construction of large-scale cut and embankment. In this study, the characteristics of special geotechnical condition and potential geotechnical risks during railway construction in the Middle East are discussed on the basis of field observation, literature review, and field and laboratory test results.

• Journal of Korea Port Economic Association
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• v.32 no.2
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• pp.39-57
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• 2016

Many countries are developing transportation technologies aimed at reducing environmental pollution and the environmental burden. For example, environmentally friendly transportation routes and methods are being used to improve inland waterways in Europe. Against this backdrop, a case study was conducted on special cargo (weight cargo, earth and sand, etc.) on Korea's Gyeong-In Ara Waterway, an inland waterway connecting the Han River and the West Sea, serving a distribution function. The results of the analysis showed that coastal shipping could be promoted using the waterway, including a positive synergy among environmental, economic, and social aspects. That is, by shifting from overland transportation to marine transportation, it is possible to reduce environmental pollution, ease traffic congestion, decrease traffic accidents, and shorten the licensing period for the weight cargo demand of the northern area of the Han River. In this respect, the Gyeong-in Ara Waterway could become an environmentally friendly transportation route, promoting coastal shipping in Korea. However, for this to occur, support systems such as subsidies for marine transportation and using the inland waterway are required, as happens in the EU. Furthermore, existing policies to promote coastal shipping should be improved and applied more broadly.

• Journal of the Korean Society of Marine Environment & Safety
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• v.23 no.6
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• pp.661-668
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• 2017

The purpose of this study is to analyze the chemical reaction pathway for explosion accident of mixed cargo. The analysis used a structural scenario using event-tree analysis. Structural scenarios were constructed by estimating various chemical reaction paths in the content of the mixed cargo accident recorded in the written verdict. The analytical method was applied to three kinds of analysis: chemical analysis based on chemical theory, quantitative analysis using chemical reaction formula, and probabilistic analysis through questionnaire. As a result of analysis, the main pathway of the accident occurred in three ways: the path of explosion due to the reaction of concentrated sulfuric acid with water, the path of explosion due to the reaction of metal and mixed acid, and the path of explosion by synthesizing with special substances. This result is similar to the path recorded in the validation, and it leads to thar the proposed path analysis method is valid. The proposed method is expected to be applicable to chemical reaction path estimation of various chemical accidents.

• Journal of the Society of Naval Architects of Korea
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• v.31 no.3
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• pp.135-144
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• 1994

The coupled vibration of the deck house and stern structure, which was experienced on a 12,900 TDW Ro/Ro ship, has been studied. It was a large-scale vibration problem where the structure resonates with the propeller excitation at the first blade passing frequency. After discussing the structural characteristics of the ship, the vibration characteristics measured ducting the sea-trial are presented and compared with the analysis results which are based on a 3 dimensional finite element(FE) model. The FE model is also used to verify various reinforcement options and to predict their effectiveness. A substantial reduction or the vibration was confirmed during the sea-trial after installing a few selected reinforcement. The forced vibration response, which is computed using the FE model, is compared with the measured data. The change of the vibration characteristics according to loading conditions is also studied.

• Tribology and Lubricants
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• v.12 no.1
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• pp.1-5
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• 1996

자성유체는 자연에서 추출한 것이 아니라 자화성(Magnetizability)과 유도성(Flowability)을 동시에 갖도록 합성한 특수액체이다. 자성유체는 1960년대 중반에 미국의 NASA에서 처음 개발된 이후로 윤활, 밀봉, 감쇄, 의료 등의 분야에서 응용연구가 많이 진행되었기 때문에 고도의 정밀도를 요하는 항공, 우주산업, 컴퓨터와 반도체 분야 등에서 실용화가 크게 진전되고 있다. 특수물질일 자성유체는 전기적으로 도체인 10nm 정도의 미세한 자기입자(Magnetic particles)에 코팅을 한 후, 이것을 물, 탄화수소, 플루오르카본, 에스터 등의 매개유체(Carrier Fluids)에 혼합시켜서 콜로이드 상태로 사용하게 된다. 자성유체는 미세한 자기입자들이 매개유체내에서 서로 충돌하면서 반발력을 발생시켜서 상호간에 늘 콜로이드 상태를 유지하고 있으며, 이 특수유체가 자기장의 영향을 받게 되면 점도가 증가하면서 특이한 성질을 갖게 된다. 상대 접촉 운동면에 경계마찰이나 혼합마찰을 하게 되면 윤활상태는 비교적 나쁘다. 이러한 마찰지역에 콜로이드상의 자성유체 윤활제를 공급하면 기존의 윤활제에 비하여 대단히 효과적으로 윤활을 할 수 있게 된다. 그러나 자성유체 윤활제가 마찰부위에 원활하게 공급하기 위해서는 미끄럼 마찰부에서 자기장을 잘 형성시킬 수 있는 도체이어야 하기 때문에 특별한 윤활 시스템 설계가 제시되어야 한다. 자성유체 윤활제는 합성으로 제조된 특수물질로 여러가지 장점을 갖고는 있으나 기존 윤활유와의 적합성, 마찰열, 밀봉압력 등의 조건에서 제한적으로 사용될 수 밖에 없으므로 항공, 우주 산업이나 석유 화학분야와 같이 특수 환경에서만 사용되고, 또한 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 정압주입시험에서도 확인된다.. It was resulted from increase of weight of single cocoon. "Manta"2.5ppm produced 22.2kg of cocoon. It is equal to 9% increase in index, as compared to that of control. In case

• Korean Journal of Heritage: History & Science
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• v.54 no.4
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• pp.60-77
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• 2021

From 2007 to 2011, four Goryeo Dynasty vessels, namely the Taean treasure ship, Taean Mado Shipwreck No.1, No.2, No.3 were discovered in Taean area, Chungcheongnam-do province. From the shipwrecks, 175 pieces of mokkan (wooden tablet) were excavated. These mokkans are the only case of Goryeo Dynasty and represent the unique usage of mokkan as cargo tags, after the paper replaced the wooden tablets as writing materials. The Taean mokkans provide details, such as the year, recipient, port of origin, types of the cargo, quantity and unit, the name of the responsible person for shipment. Thus, they enable us to speculate about the characteristics of the cargo. Furthermore, through studying the writing style, form, material and manufacturing method, researchers can extract which form and characteristics were favored at that time. The Taean mokkans have no preset style for writing. Therefore, they can be written selectively and freely. And since the mokkan were attached to cargos, mokkans with furrows on upper side were favored, and efficiency and simplification of the manufacturing process were priorities in making mokkans. The Taean mokkans can be compared to those from the Shinan ship and the Quanzhou ship because those are of the same era and use. On the writing styles and information, Chinese mokkans are focused on the cargo owners, while The Taean mokkan includes more detailed information, such as the recipients. In forms, Chinese mokkans have maximum thickness of 1.0 centimeter and have pointed edges in lower parts, while mokkans from Taean do not have fixed thickness or edges. Furthermore, Chinese mokkans and Korean mokkans have different styles from manufacturing methods and material selections. These differences between Chinese and Goryeo mokkan are related to the differences between littoral-transport Goryeo ships and ocean-transport Chinese ships, such as shipping distances, types of cargo, shipping systems, packing methods, and transport operators. At the moment, because there are only small amount of data and materials of Chinese mokkan, comparative studies regarding Goryeo and Chinese mokkan can only be fragmentary. However, this article can be a base from which to expand the scope of Goryeo mokkan studies.

• Proceedings of the Safety Management and Science Conference
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• 2000.05a
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• pp.351-360
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• 2000

선석배정문제는 항만운영 및 관리의 첫단계이며, 각 항만의 지리적, 자연적 특성에 따라 매우 독특하면서 복잡한 성향을 띠고 있다. 특히, 인천항은 그 지리적 특성상 갑문이라는 특수한 시스템과 많은 종류의 화물을 취급하기 때문에 만성적인 체선·체화 현상을 보이고 있으며 많은 물류비의 상승 등 경쟁력을 상실하고 있는 실정이다. 본 연구에서는 인천항의 갑문이용과 선석의 배정문제에 있어서 실제 인천항을 운영하는 전문가 집단의 지식을 규칙화하고, 실제자료를 토대로 갑문의 영향을 분석하여 보다 효율적으로 운영할 수 있는 시스템과 예기치 못한 상황에 대한 대처를 원활히 할 수 있는 선석운영 의사결정지원시스템을 구축하였다. 특히 본 연구에서는 기존 연구에서 고려하지 못한 갑문을 중심으로 교차제한사항과 선석운영의 효율을 높일 수 있는 이안을 예상한 입항선박을 고려하였으며, 더 나아가 사용자로 하여금 쉽고 빠르게 선석을 운용할 수 있도록 개선된 그래픽 사용자 인터페이스(Graphic user Interface)를 갖는 대화식 접근법(User interactive approach)체제의 실시간 선석운영 의사결정지원시스템을 개발하였다.

• Journal of Korea Port Economic Association
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• v.26 no.3
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• pp.42-55
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• 2010

This paper primarily deals with a decision-making for determining the number of voyages in each ship size under a specific port structure in order to minimize the total transport cost consisting of transport cost at sea, queuing cost in port, and inventory cost in yard. As a result of computer simulation using queuing model characterized by inter-arrival time distribution, we were able to find out some combination of voyage numbers of 3 ship-size(50,000-ton, 100,000-ton, and 200,000-ton), where the total transport cost can be minimized under a specific port structure. The simulation model also allows us to figure out any trade-off relationship among sea transport cost, queuing cost in port, and inventory cost in yard. Put it differently, an attempt to reduce the sea transport cost by increasing the number of voyages of the largest ship size, the transport cost incurred in both port and yard is hypothesized to be increased and vice versa. Consequently, Port managers are required to adjust the number of annual number of voyages allocated in each ship size, put into the sea lines for importing raw materials, in order to optimize the transport costs incurred under the specific port system. We may consider a net present value(NPV) model for performing an economic feasibility analysis on port investment project. If a total discounted net benefit, including cost savings, exceeds the initial investment for an additional berth construction, then we accept the port investment project. Otherwise, we reject the proposed port investment plan.

• Fire Science and Engineering
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• v.31 no.2
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• pp.119-126
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• 2017

This study examined the soundness, vibration, and size of ambulances currently used in Korea as well as the comfort and convenience of ambulancesin Korea. The target vehicles were measured and investigated using the currently used freight type, van type, and Benz ambulance. Currently, the ambulance standards in Korea have only formal production standards, and there is no regulation on safety for ambulances, space regulation for first aid, comfort, and convenience. Therefore, comparative experiments on the comfort and convenience were measured using noise and vibration measurement experiments, and research was conducted on the size and interior rearrangement of ambulances to investigate the areas that can improve the comfort and convenience. The noise measurementsshowed that the noise was large in the order of the van type, Benz type, and freight type. In the case of a speed of 40 km/h or more, the noise measurement result was 60 to 70 dB or more. In the case of vibration, the Benz type and van type ambulance were good, and the vibration of the freight type showed the worst result, highlighting the need for improvement. Lastly, it is not possible to increase the internal size of the structure of domestic ambulance. On the other hand, it is important that through ambulance relocation and the position of first aid personnel, it will be possible to use it more comfortably and conveniently.