• 한국해양공학회지
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• 제34권5호
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• pp.361-370
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• 2020

We developed a heavy-duty work class ROV trencher named URI-T (Underwater robot it's trencher) that can conduct burial and maintenance tasks for underwater cables and small diameter pipelines. It requires various supporting systems, including a dynamic positioning (DP) vessel, launch and recovery system (LARS), A-frame, and winch in order to perform burial tasks because of its dimensions (6.5 m × 5.0 m × 4.5 m, 20 t) and the tough working environment. However, operating a DP vessel has disadvantages as it is expensive to rent and operate and it is difficult to adjust the working schedule for some domestic coast construction cases. In this paper, we propose a method using a barge instead of a DP vessel to avoid the above disadvantages. Although burying the cable and pipeline using a barge has lower working efficiency than a DP vessel, it can save construction expenses and does not require a large crew. The proposed method was applied over two months at the construction of the water supply in Yokji-do, and the results were verified.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회B
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• pp.3215-3220
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• 2007

Gas-liquid separator has been designed for the sake of reducing expenses associated with production operations. To date, a number of gas-liquid separators have been installed and put to use for various applications. Despite the advantages of simple and compact configuration of separator with no moving part, its efficient operation is limited in terms of total pressure losses, separation performance and flow-induced noise and vibration, which are closely associated with the very complicated flow phenomena involved. In the present study, a gas-liquid centrifugal separator with a swirl vane is investigated for the purpose of water separation from compressed moisture air. The 3D Navier-Stokes equations are numerically solved using a fully implicit finite volume scheme. Based upon the obtained solutions, tangential velocities, centrifugal forces, vortices and total pressure losses are analyzed to find out the best design parameters. From the present study, several attempts are made to improve the performance of conventional separators of centrifugal type.

• 산업공학
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• 제17권1호
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• pp.71-77
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• 2004

At the present time, container transportation plays a key role in the international logistics and the efforts to increase the productivity of container logistics become essential for Korean trucking companies to survive in the domestic as well as global competition. This study suggests an approach for determining fleet size for container road transportation with dynamic demand. Usually the vehicles operated by the transportation trucking companies in Korea can be classified into three types depending on the ways how their expenses occur; company-owned truck, mandated truck which is owned by outsider who entrust the company with its operation, and rented vehicle (outsourcing). Annually the trucking companies should decide how many company-owned and mandated trucks will be operated considering vehicle types and the transportation demands. With the forecasted monthly data for the volume of containers to be transported a year, a heuristic algorithm using tabu search is developed to determine the number of company-owned trucks, mandated trucks, and rented trucks in order to minimize the expected annual operating cost. The idea of the algorithm is based on both the aggregate production planning (APP) and the pickup-and-delivery problem (PDP). Finally the algorithm is tested for the problem how the trucking company determines the fleet size for transporting containers.

• 한국태양에너지학회:학술대회논문집
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• 한국태양에너지학회 2008년도 춘계학술발표대회 논문집
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• pp.80-85
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• 2008

A PVIB(Photovoltaic in Building) system is united by a constituent outer covering and can expect dual effects that reduce expenses for the establishment of a PV system. It is a profitable technology because it does not need a building as it is a stand alone PV system. This paper presents design, operational features analysis, and PCS(Power Conditioning System) of grid-connected 30kW PVIB set up on the library of Dongshin University. For a sustainable photovoltaic system in this area, the data of the PVIB system are collected and analyzed by monitoring system using LabView. PCS of the grid-connected PVIB system, also, is designed for optimal operation with characteristics suggested in this paper.

• 수산경영론집
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• 제28권1호
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• pp.51-70
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• 1997

The fishing industry of Korea is now i a critical transitional stage. That is, broadly speaking, there are two dominant factors that constrain the further development of Korea fishey and effective competition in the international fishing industry. First of all, the global fishing industry has experienced many significant changes due to the execution of U.N, maritime law, the establishment of EEZ(the Exclusive Economic Zones), the increased roles of WTO(the World Trade Organization) as well as Korea being a member of OECD(the Organization for Economic Co-operation and Development). Second, the fishing industry of Korea is faced with the following domestic troubles, such as the icreasing fishing expenses, insufficient labor supply, and the collapse of traditional local co-operative organizations of fishing villages, etc. However, the demand for aquatic products of home consumers not only continues to increase but also is shifting to select more valuable species, completely ignoring the above-mentioned serious pressures incurred by the Korean fishery. To solve these problems and keep developing steadily, it is necessary for the fishing industry of Korea to adopt a more active and flexible development pattern in order to reset up the regional economic base in fishing villages nation-wide and make the exploitation of fishing resources balance. The paper gives an reconsideration to the primary alternatives facing the Korean fishery and its prospective roles in a realistic and far-sighted attitude. It may serve as an endeavour in seeking an outlet for the fishing industry of korea to advance forwardly and lastingly.

• 한국환경과학회지
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• 제14권3호
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• pp.335-343
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• 2005

The objective of this research is to evaluate a feasibility of wastewater reuse by membrane treatment with vibrating membrane separation equipment. Molecular weight of compounds in wastewater, permeability of membrane and retentate characterization after membrane filtration were investigated in order to determine appropriate membrane pore size and materials for wastewater treatment. Selected membrane was evaluated with vibration membrane separation equipment to optimize operating conditions. The following conclusion are drawn. 1. We got as following test results after the distribution of particles in the semiconductor wastewater, are made up of $1\~20{\mu}m$. Si, gold and Al in turn are contained in semiconductor wastewater. 2. Recovery rate is changeless under increasing recovery rate in operation. Though a value can be if pressure can be changed, the highest value of permeate rate is presented in 150 psi. 3. The AS-100(polysulpone) was selected as the most appropriate membranes for the treatment of semi-conductor wastewater to VSEP system. The fouling almost did not occur during this experiments. The analyses of treated water with VSEP system showed conductivity: 0.059,us/cm, TDS: 40mg/l, COD: 20mg/l, SS : 5mg/l, n-Hexane: 8.3mg/l. Comparing previous systems, operating expenses is decreased by more $50\%$.

• 한국수소및신에너지학회논문집
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• 제25권2호
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• pp.139-144
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• 2014

A Fuel Cell is one of the solving to reduce greenhouse gases. Despite the high efficiency and environmental friendly of Household Fuel Cell System it has hardly obtained popularity mainly due to its high prices. In order to encourage use of the system prices and operational expenses need to become economical. In this study, optimization through simulation was conducted to find out the optimal operational condition. As a result of simulation the system is operated with DSS operation from 5 O'clock until 19 O'clock for 13 hours at the constant output of 0.4kW to maximize reduction of energy rate. Furthermore, instead of the domestic system with the rated output of 1kW, rated output of the system should be reduced to 0.4 - 0.6kW which can promote installation of household Fuel Cell System.

• 한국건설관리학회:학술대회논문집
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• 한국건설관리학회 2006년도 정기학술발표대회 논문집
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• pp.111-116
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• 2006

정부는 BTL(Build-Transfer-Lease)사업으로 교육시설 분야에 2005년부터 3년간 13조원의 재원을 투여하여 교육시설을 획기적으로 개선하겠다고 발표하였으며, 현재 각 지역교육청별로 교육시설물에 대한 BTL 사업을 지속적으로 발주하고 있는 추세이다. 이에 본 연구에서는 교육시설물에 대한 현행 BTL 사업 적격성 평가방식의 효율성 제고를 위해 객관적이며 효율적으로 정량적 VFM 분석을 실시할 수 있는 BTL 사업 적격성 평가 시스템의 핵심 모듈을 제안하였으며, 이를 통해 명확한 BTL 사업수행 비용에 대한 예측 및 적격성 평가방식의 도입을 위한 기초자료를 제시하고자 한다.

• 대한공간정보학회지
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• 제12권2호
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• pp.73-77
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• 2004

대도시의 도심 정체나 대중교통 장려책과 같은 요소로 인해 대중교통에 대한 관심과 이용도가 증가하고 있다. 그러나 노선의 설계나 배분에 관한 연구가 미흡하고 적절한 정량적인 방법론이 구축되어 있지 않기 때문에 설계, 운영에 어려움을 겪고 있다. 노선의 공급과잉이나 공급부족으로 인해 접근성이 지역간에 편중되어 나타나며, 도시 각 구역의 정류장은 다른 지역으로 이동하는 시간과 비용, 심적 부담에 있어 큰 편차를 보이고 있다. 한편, Space Syntax 이론은 도시공간이나 건축공간의 접근성을 공간의 기하학적인 연결구조에 기반하여 정량적으로 산출하는데 사용되는 이론이다. 본 연구는 Space Syntax 이론을 대중교통 문제에 효과적으로 적용하기 위해 알고리즘을 수정하였으며, GIS를 이용하여 간략한 가상의 네트워크를 구축한 후 이를 적용하는 과정을 예시하였다.

• 한국건설관리학회논문집
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• 제8권5호
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• pp.132-141
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• 2007

BTL 사업 대상 중 교육시설물은 교육인적자원부에 따르면 2007년까지 3개년에 걸쳐 13조원 이상 규모의 BTL 민간투자 사업을 발주하기로 하는 등 교육시설물의 건설은 국내 공공시설물 건설 사업에서 큰 비중을 점하고 있다. 본 연구에서는 교육시설물 BTL 사업의 비용 항목 중 운영관리비에 해당되는 위생관리비 산정 방법을 제시하였다. 또한 이를 바탕으로 유지관리 시스템의 주요 모듈을 개발하고, 개발된 모델의 타당성을 입증하기 위해 대안별 비용의 비교 분석을 실시하였다.