• Journal of Advanced Marine Engineering and Technology
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• v.39 no.9
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• pp.973-980
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• 2015

With their wide geographical distribution, unconventional resources are continuously compared against conventional resources, but their development is expanding because TRRs (Technical Recoverable Resources) are similar to conventional resources. In particular, there is active development of unconventional gas resources such as shale gas, tight gas, CBM (coalbed methane) and gas hydrate. However, it is difficult to calculate the material properties of unconventional resources, especially the gas content, with current geophysical logging technology. Additionally, some overseas companies have monopolies on related equipment and materials. Therefore, this study developed a reservoir PCS (Pressure Core Sampler). It can collect core samples without gaseous loss by maintaining high pressure from the moment the core is sampled and record pressure and temperature in real time. Successful performance testing was also carried out for official verification of the manufactured PCS. The reservoir PCS will contribute to the acquisition of geophysical well logging data as well as accurate and reliable cores.

• Journal of the Korean Operations Research and Management Science Society
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• v.17 no.1
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• pp.41-41
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• 1992

In the real world situations that some jobs need be processed only on certain limited machines frequently occur due to the capacity restrictions of machines such as tools fixtures or material handling equipment. In this paper we consider n-job non-preemptive and m parallel machines scheduling problem having two machines group. The objective function is to minimize the sum of earliness and tardiness with different release times and due dates. The problem is formulated as a mixed integer programming problem. The problem is proved to be Np-complete. Thus a heuristic is developed to solve this problem. To illustrate its suitability and efficiency a proposed heuristic is compared with a genetic algorithm and tabu search for a large number of randomly generated test problems in ship engine assembly shop. Through the experimental results it is showed that the proposed algorithm yields good solutions efficiently.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.43 no.2
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• pp.172-178
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• 2015

The control moment gyroscope(CMG) which is well known as an effective high-torque-generating device is applicable to space vehicles, airplanes, ships, automobiles, robotics, etc. for attitude stabilization and maneuver. This paper deals with the overall details of 100Nm-class CMG development for various industrial applications, and provides the activities and results associated with the CMG system-level requirement analysis, the motor subsystem design/manufacturing/integration, the construction of ground support equipment, and the performance test and evaluation. The performance test reveals that the CMG generates the torque output more than 120Nm in as-designed operation of spin motor and gimbal motor.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.56 no.2
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• pp.155-162
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• 2020

The adjudication of Korean Maritime Safety Tribunal (KMST) was analyzed to collect basic data to identify the cause of the risk that did not appear in the current data provided by the fishermen's occupational accidents of the National Federation of Fisheries Cooperative (NFFC) in stow net fishing vessel from 2015 to 2019. The personnel's carelessness was the most common in 29 out of 33 accidents (87.9%), followed by 25 cases (75.8%) of inadequacy of instructions, 24 cases (72.7%) of inadequacy of education on hazard factor, 20 cases (60.6%) of no personal protection equipment, 18 cases (54.5%) of poor guard, 17 cases (51.5%) of inadequacy of work method, 16 cases (48.5%) of absence of emergency stop button, 14 cases (42.4%) of work practice of poor safety precautions that affected more than 40% of all accidents as accident causes. These causes had a strong influence on each other, and the ratio of accident causes is high. With this relationship, accidents can be prevented or the severity of human injury can be reduced if types of accident process can be estimated with a scenario, and the key points before the accident in the scenario are switched to safe points.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.56 no.2
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• pp.183-192
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• 2020

This study conducted the experiment for the development of the low pressure type SCR system. The experimental equipment of SCR system was installed, which was widely used as the nitrogen oxides abatement system, and the demonstration experiment was conducted to see that it met the Tier III regulation according to the IMO NOx Technical Code. The SCR system demonstration experiment was divided into three stages: SCR system component operation test, engine parameter test by engine load, and NOx abatement performance and ammonia slip verification test. The final performance of the SCR system was verified through analysis of NOx abatement performance and ammonia slip test results for each load variation.

• Journal of the Korean Society of Marine Environment & Safety
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• v.20 no.1
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• pp.78-85
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• 2014

LNG-RV has the additional equipments that enable to re-gastify liquefied LNG in LNG carrier. This vessel has Submerged Turret Loading(STL) system which transports gas through submarine terminal. When LNG-RV is operating at sea, the opening condition is formed by detaching STL equipment from a vessel. The primary objective of the current work is to estimate accurate speed loss for the opening condition of the LNG-RV employing numerical calculations and model tests. In the model tests, resistance and self-propulsion tests are carried out for the bare-hull and the opening condition without STL. In addition to these, flow visualization utilizing tuft is used to make the flow patterns visible, in order to get a qualitative or quantitative information for inner part in case of detaching the STL.

• The KSFM Journal of Fluid Machinery
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• v.19 no.4
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• pp.48-53
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• 2016

The centrifugal separator which uses gravity separation method for oil-water separation, rotating at high-speed, is one of the most commonly used device for controlling the amount of the oil in waste water collected in bilge. The IMO (International Maritime Organization) has set regulations, also known as MARPOL 73/78, for the prevention of marine pollution. In addition, DET NORSKE VERITAS (DNV) has set standards regarding the assignment of Environmental Class Notation, CLEAN or CLEAN DESIGN, of ships. One of the requirements for classification is that in addition to conforming to MARPOL 73/78, more stringent measures must be taken as well. One of these measures is to limit the oil concentration in bilge water to less than 5ppm. So in this study, an Oil-Water Separator (OWS) is used together with multiple separating plates as a filtration system to be used as an oil-water separation device. The OWS operates using centrifugal separation in which the mixture is separated by centrifugal forces. The main purpose of this paper is to present the OWS separation efficiency according to the rotation speed, mass-flow rate, the angle and the number of stacked layers of the laminated plate using Computational Fluid Dynamics (CFD). Improvements to the device will be investigated from these results.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2004.11a
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• pp.57-61
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• 2004

According to the research result of existing regarding the seabed organic sediment, contamination it flows from the land and the sea become the enemy in the coastal water. It was caused with the summer season water temperature rise and dispersing recall respect advancement. Phosphorus which is a main reason of red tide actual condition came to reveal vast quantity with the facts that it gushes. Specially, in the case of the coastal closing waters and the nursery, as the corpse and the fresh fish washing veterinarian was imbrued, it is the actual condition where is more deepened. Consequently the development of shallow layer dredging method of that suction power which is stabilized is demanded to be able to dredge only the sediment layer which has not become the pressure and is a main reason of being imbrued. The dredging methods using the pressure difference minimize the suction of the seabed sediment. This method is stable that suction power which occurs from guard difference of the guard and the guard of the dredging system inland water. That's why it is possible to sort dredging of the organic sediment ranging in upper layer sediment and it will be able to expect the minimization of dredging quantity. Increase of the expense that it followsin orthocenter with the fact will not grow. Because the pressure difference of the dredger inland water is occurred by the suction power. Maintenance administrative costs are reduced, because the one of smallest dredging system maneuvers and the barge which affixes an integrated operation system is mainly in a resting. To reduce a dredging hour, it will be able to solve in the condensed water as operating the jar guard post.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2002.05a
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• pp.205-208
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• 2002

When establishing the submarine optical fiber table between international and domestic, marine survey in advance it grasps the submarine geological features which is accurate and a depth of water condition. And the route which is safe for selecting and submarine optical fiber cable laying it is a work which secures an ease one location. If also, the PLGR the submarine of optical fiber table root the sea contamination material (rope, wire and net) it removes in advance and if the submarine of the optical fiber cable ease it does to arrive safely. And it is a work the Plough and ROV laying work hour laying work efficiency improvement and laying equipment it will be able to protect. So, This paper presents the monitoring system of ship information management and operation for marine survey and PLGR work in submarine optical fiber table construction enterprise. In order to achieve these purpose, overall serial multi-port communication modulo of configuration, realtime processing for management and operation of receiving data, realtime graph and a printout are described.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.9
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• pp.1796-1807
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• 2017

The domestic warship propulsion system is at the stage of a hybrid propulsion system changing from a mechanical propulsion system and the propulsion system becomes complicated so it is expected that the function of ECS(Engineering Control System) that controls and monitors the warship propulsion system becomes important. Recently the development of ECS has progressed domestically, so that verification of reliability and stability is required in the process of ECS development. The simulator to be proposed is composed of HILS, it can be divided into a shaft-line dynamics model of the simulating power transmission, a controller model of the simulating the control of the equipment, and a communication model communicating with the ECS. In this paper, we developed simulator for ECS verification for CODLOG hybrid propulsion system, set scenario, and conducted simulation.