• 한국항해항만학회지
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• 제28권5호
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• pp.365-372
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• 2004

LNG 운반선은 항해중 외부로부터 다량의 열 침입으로 인해 많은 BOG가 발생하며 통상 이는 선박엔진의 연료로 사용된다. 화주의 입장에서 이러한 BOG의 발생과 소비는 화물의 손실을 의미하며, 따라서 선주와 화주 사이에는 BOR에 대해 만선항해를 기준으로 0.15%/day 이하가 되도록 운송계약을 체결한다. LNG 운반선의 항해사관 입장에서는 자신이 승무하고 있는 선박의 BOR에 대한 정확한 지식을 바탕으로 선박을 운항할 필요가 있으나 실제로는 막연한 경험에 의존하고 있는 실정이다. 따라서 본 연구에서는 신체온도분포 및 외부로부터의 침입열량에 관한 정밀 열설계 기술을 토대로 본선의 해기사들이 보다 간편하게 BO를 예측할 수 있는 간단한 모델을 제시하였다. 그리고 개발된 모델을 사용하여 연구대상 선박의 설제 기상조건을 토대로 만선 및 공선항해에 대하여 각각 BOR을 계산하였으며 이를 실측자료와 비교, 검토하였다. 본 연구에서 제시된 BOG 예측방법은 현재 운항중인 LNGC에서 BOG를 관리하는 유용한 도구로 사용될 것으로 기대된다.

• 대한공간정보학회지
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• 제23권3호
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• pp.95-106
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• 2015

유휴공간은 기존 도로의 선형개량 및 신규노선 건설, 도로 확장공사 등으로 도로 본래 기능을 상실하여 방치된 도로 부지로 추가적인 활용이 가능한 공간이다. 그러나 현재 일부 유휴공간은 과적 검문소, 자재 적치장, 차량 대기소 등의 소극적인 유지관리와 활용이 이루어지고 있지만 대부분의 유휴공간에 대한 체계적인 관리방안과 활용방안이 필요한 실정이다. 본 연구에서는 공간정보 오픈 플랫폼(브이월드)를 이용하여 유휴공간의 입지조건, 지형특성, 지역 및 문화 특성을 분석하고 유휴공간의 유형을 분류하기 위한 기준을 정립하였다. 유휴공간의 유형에 따라 공간정보 오픈 플랫폼을 이용해 3차원 모델링을 수행하고 주변 환경과 경관을 고려한 활용 및 개발 모델을 제시하였다. 향후 강원권 국도 유휴공간의 개발계획 및 설계방안을 도출하여 유휴공간의 활용에 도움이 되고자 하였다.

• 한국ITS학회 논문지
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• 제21권5호
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• pp.183-196
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• 2022

국내의 경우 대중교통 최소서비스 수준 분석을 통해 대중교통 접근성을 평가하고 있으나 이는 운영자 측면의 평가로 이용자 측면의 대중교통 접근성 분석은 이루어지지 않고 있다. 이에 본 연구에서는 알뜰교통카드 데이터를 이용하여 이용자의 대중교통 접근성을 분석한 결과 법정동보다 법정리의 접근시간 및 거리가 크며, 대중교통 접근성이 낮은 유형을 분류하여 분석한 결과 전체 평균 접근 시간에 비해 유형 1은 95%, 유형 2는 64% 더 크게 나타났다. 이러한 대중교통 접근성 문제 해결을 위해 델파이 조사를 통한 실시간 수요대응 자율주행 대중교통차량의 효율적인 도입 방안을 제시하고자 하였다. 델파이 조사 결과 기능은 환승연계 및 D2D, 서비스는 예약 및 정보제공서비스, 노선 운영 방식은 준동적 및 동적 운영, 접근거리는 300m, 노선 운행 거리는 10km, 정시성은 5분 이내와 같이 9개 항목에 대해 전문가들의 의견이 일치하였다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 춘계학술대회 논문집
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• pp.332-336
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• 2011

IN THIS STUDY, BASED ON THE TYPE OF HIGH SPEED RAILWAY TRACK VIBRATION CHARACTERISTICS WERE MEASURED AT KTX VEHICLE. KTX ROUTE BALLASTED TRACK HAS BEEN INSTALLED TOGETHER WITH THE CONCRETE TRACK. CONCRETE MUST BE TRACK IRREGULARITY THAN BALLASTED TRACK, VEHICLES VIBRATION VALUES THAT ARE SMALLER. ALSO, IN TERMS OF MAINTENANCE, CONCRETE TRACK IS KNOWN TO BE MORE FAVORABLE THAN THE BALLASTED TRACK. PHASE 2 IS THE KTX, DAEGU - BUSAN IS A SECTION OF CONCRETE TRACK. IN THIS STUDY, "KUUNG-BU HIGH-SPEED RAILWAY LINES" INSTALLED ON THE CONCRETE TRACK AND BALLASTED TRACK KTX FROM THE VEHICLE WHEN INSTALLED BETWEEN RAILS, SLEEPER AND BALLAST ON THE TRACK WAS MEASURED VIBRATIONS.

• 한국토양비료학회지
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• 제47권2호
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• pp.80-84
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• 2014

Phosphorus (P) is an essential nutrient for all living organisms. P is mostly obtained from mined rock phosphate. However, existing rock phosphate reserves could be exhausted in the next 50-100 years. As Korea is totally dependent on imported rock phosphate, we should seek for solution to overcome the P depletion by efficient use and recycling. For this, this study suggested a P flow model to identify the location and flow route of P in urban area based on traditional material flow analysis. The type of P entering the urban areas are fertilizer, food and feed. Each type of P is used in agriculture, human consumption and animal husbandry. After going through each process, P is moved to waste management facilities within food waste, excreta and sewage. Some portion of P in waste are buried, incinerated and discharged, which can be reservoir of P in the future.

• 대한조선학회논문집
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• 제47권3호
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• pp.469-475
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• 2010

The operation scenarios, types of ice, draft and propulsion system are important design point on the beginning stage of the ice breaking vessel. The concept of hull form in ice breaking vessel has to compromise the performance according to the operation route especially if ship is operating in ice and ice free water. The several hull forms were proposed to optimize the capability of the vessel in this paper. The effect of hull form according to type of ice is also discussing and explaining the ice resistance in each ice type as like pack ice, brash ice, level ice, rubble ice and ice ridge. The draft effect was examined and propulsion system for example FPP(Fixed pitch propeller), CPP(Controllable pitch propeller) and POD system was compared focusing on the propulsion efficiency.

• Journal of Advanced Marine Engineering and Technology
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• 제32권8호
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• pp.1192-1200
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• 2008

This paper is concerned with the thermal design of the $138,000m^3$ class membrane type LNGC. To predict the temperature distribution, BOG and BOR, 3-dimensional numerical calculation was carried-out for the quarter of No.3 LNG tank. These sequence analyses were performed under the standard conditions of IMO ship design condition, USCG ship design condition and the Korean flag LNGC's route condition according to the 6-voyage modes. As the results, temperature behavior, heat flux, total penetrating heat, BOG and BOR were obtained, and those were compared with the maneuvering results considering the real temperature variation of air and sea water temperature at noon time. For securing the safety of LNGC during the ballast voyage, optimum control patterns of pressure and temperature in LNG tank is suggested in this paper.

• 한국세라믹학회지
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• 제29권11호
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• pp.855-862
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• 1992

Thermoelectric power, electrical conductivity and Hall effect were measured, as functions of temperature in the range of 100 to 600 K, on polycrystalline Bi4/3Sb2/3Te3 which had been prepared via uniaxial hot-pressing at different temperatures in the range of 373 K to 773 K, aiming at searching a profitable processing route to a polycrystalline thermoelectric material, a promising, viable alternative to a single crystalline one. It was found that, with increasing temperature of pressing under a fixed pressure, the material, normally a p-type prior to being hot-pressed, underwent a transition to n-type. This transition was confirmed to be due to plastic deformation during hot-pressing and interpreted as being attributed to the change of the major ionic defect BiTe' into TeBi˙at temperature high enough for structure elements mobility. Thermoelectric figure-of-merit of the hot-pressed material was discussed in connection with the p-n transition in addition to microstructure.

• 한국경영과학회지
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• 제29권4호
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• pp.175-187
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• 2004

We consider the simultaneous selection of part routes for multiple part types in Flexible Manufacturing Systems (FMSs). Using an optimization framework we investigate two alternative route assignment policies. The one, called routing mix policy in the literature, specifies the optimal proportion of each part type to be produced along its alternative routes, assuming that the proportions can be kept during execution. The other one, which we propose and call pallet allocation policy, partitions the pallets assigned to each part type among the routes. The optimization framework used is a nonlinear programming superimposed on a closed queueing network model of an FMS which produces multiple part types with distinct repeated visits to certain workstations. The objective is to maximize the weighted throughput. Our study shows that the simultaneous use of multiple routes leads to reduced bottleneck utilization, improved workload balance, and a significant increase in the FMS's weighted throughput, without any additional capital investments. Based on numerical work, we also conjecture that pallet allocation policy is more robust than routing mix policy, operationally easier to implement, and may yield higher revenues.

• 한국항만경제학회:학술대회논문집
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• 한국항만경제학회 2007년도 정책세미나 및 국제학술대회
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• pp.37-50
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• 2007

Taking advantage of geographical position of Korea located on the main route of world-wide service, Port Logistics Industry can be strategic industry which secures international competitiveness necessary for Korea to be hub of Northeast Asian's logistics. Along with the advent of super large container vessel, world ports environment changed from "milkway" type, which means vessel calls every port for service to "Hub & Spoke" type, which means vessel calls regional central port and feeder service for the rest ports. As environment changes, regional ports in Northeast Asia are competing each other tougher and tougher and introducing or developing port logistics information system based on state-of-the-art technology in order to adapt themselves to new environment, thus to be Hub port. Taking this situation into consideration, we want to define clearly the meaning and scope of port logistics IT and review the global trend of port logistics IT. Finally we want to find future development of port logistics IT which we have to achieve.