• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.53 no.2
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• pp.204-209
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• 2017

In order to use PUR/CuO Composites as the sealing materials for ships equipment, this research has been performed. PUR/CuO composites are produced by using ultrasonic waves. The increase of CuO leads to increase in the tensile strength and shore hardness. The cumulative wear volume shows a tendency to increase in proportional to sliding distance. As the CuO particles of these composites indicated, the friction coefficient was slightly increased. The major failure mechanisms were lapping layers, deformation of matrix, plowing, debonding of particles and microcracking by scanning electric microscopy photograph of the wear tested surface.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.56 no.1
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• pp.71-81
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• 2020

This paper proposes a possibility of using active front-end rectifier with the SVPWM method for induction motor speed control, which is applicable to small electric propulsion boats. The proposed method can produce a more precise sinusoidal input current waveform and a higher power factor than conventional methods. Its speed, torque, input current, DC voltage, and load current control performance are similar to or better than those of conventional methods. Through computer simulations using the PSIM program, the validity of the proposed method was verified by comparing and analyzing the characteristics of the conventional methods and the proposed method.

• Transactions of the Korean Society of Mechanical Engineers
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• v.17 no.8
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• pp.2023-2032
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• 1993

This study suggests a new type shaft generating system driven by hydrostatic transmission suitable for small size vessels. Since the shaft generating system is affected ceaselessly by disturbances such as speed variation in pump driving speed and variation in external load, a robust servo control must be implemented to obtain stable electric power with constant frequency. Thus, in this study, a digital robust servo control algorithm is applied to the controller design. By the experiment and the numerical computation, the frequency variation characteristics of the generating system under various disturbances are investigated. Conclusively, it is said that the shaft generating system proposed in this study shows excellent control performances.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.64 no.6
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• pp.878-884
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• 2015

In this paper, Power Management System(PMS) simulator for Liquid Nature Gas Carrier(LNGC) is developed. Major components of power system for LNGC, such as generator, diesel engine and governor, transformer, circuit breaker, and 3 phase loads models are built based on MATLAB/SIMULINK. With these designed major parts, PMS simulator modeling is carried out. Based on MATLAB/Graphical User Interface, PMS simulator control for LNGC, and Human Machine Interface for monitoring is designed. PMS simulator for LNGC carries out simulation according to sequence of characteristics analysis. By comparing results of predicted simulation for each sequence to that of characteristics analysis, the reliability of PMS simulator for LNGC will be verified.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.11b
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• pp.453-458
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• 2002

This paper deals with the vibration reduction of hull mount system of ship structures brought by ER smart structures. The hull mount is used to isolate the vibration of equipment from the host structures. Utilizing the tunable characteristics of ER fluids, ER inserts are made in the hull mount structure. Different types of ER inserts are proposed and the vibration characteristics are investigated. A hull mount structure is made and the influence of ER inserts are experimentally studied. An extensive modal test is empirically conducted to identify natural frequencies and mode shapes according to the applied electric field and the types of ER insert. The frequency tunable characteristics of ER inserts can be applied to many mounting structures for vibration reduction.

• Korean Journal of Computational Design and Engineering
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• v.16 no.5
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• pp.323-330
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• 2011

Large number of part design such as for aircraft and automotive development is preceded by functional or sectional design groups for efficiency. With the assembly development of large number of parts, interferences and gaps can be found when the parts and sub-assemblies by those design groups are to be assembled. When rainwater come into the space among parts and is not be drained sufficiently, rainwater within the structure can backflow to gaps or unexpected outlets, which may cause severe problems of part corrosion and electric shock. This research has developed a method and a program to simulate backflow of rainwater within space among parts, which can find unexpected outlets and gaps as in real situation. The developed program can not only simulate up and downstream of liquid, but also the flow with multiple channels of division and joining. The developed method can also be applied to aircraft and ship design process.

• Proceedings of the KIEE Conference
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• 2004.07d
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• pp.2643-2645
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• 2004

The underwater system autonomously is navigated by using the wireless communication system, which receives the control signal from surface ship. The study proposes the new media access control protocol for underwater vehicles network in the view of communication distance and as CSMA(Carrier Sense Multiple Access) for the existing networks is intended to communication network using the high speed media such as electric signal or microwave signal, and thus it may introduce the reduction in throughput when applying the protocols to underwater communication network.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.1063-1066
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• 2003

A flow-meter and its measurement controller was developed for a hydraulic system. This study, for development of positive displacement flow-meter, consist of PIC(Peripheral Interface Controller) controller with MR(Magneto-resistive) sensors. This flow-meter is used valve position indicator for valve control system by hydraulic. The MR sensors are used for the rotation of OVAL gear that detecting device. In the ship environments, consideration that necessary explosive proof. Thus electro device or electro flow-meter needs explosion design for electric circuit. We designed noncontact type flow-meter and evaluated the safety and measuring abilities.

• Proceedings of the KIEE Conference
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• 1998.07b
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• pp.650-653
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• 1998

In this paper, when we control Elevation Angle and Azimuth Angle of Antenna, intend to implement sensor system for stabilization control of antenna pedestral system because of wind in land, wave and external disturbances such as rolling, pitching, and yawing. Therefore, this sensor system is consist of Tilt Sensor for measuring absolute angle of roll ing and pitching, Level Rate Sensor, Cross Level Rate Sensor, Azimuth Rate Sensor for controlling short_term azimuth angle and Flux Gate Sensor for measuring long_term azimuth angle.

• Proceedings of the Safety Management and Science Conference
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• 2009.11a
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• pp.209-221
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• 2009

In the steel industry, steel is manufactured and processed to produce a variety of steel products. The industry provides fundamental materials to the whole range of industries including car, ship, electric appliance and construction industries, so that it is very important as an infrastructure industry. The steel manufacture process involves aerial work, many danger factors caused by the treatment with hazardous gases including BFG and COG and by high pressure gases including H2, O2, N2 and LPG. It requires the management over the large area because many workers work in a plant. The potential dangers in the steel plant were identified and the effect of the danger assessment was verified through the analysis of the danger assessment for the steel plant. The allowed degree of danger was lowered after the improvement through the danger assessment in the plant where the case studies were conducted, which indicates that the danger assessment is highly effective.