• Proceedings of the Korean Society of Marine Engineers Conference
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• 2011.06a
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• pp.188-188
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• 2011

This paper describes the propagation characteristics of acoustic signals as a function of distance from the location of partial discharge(PD) occurrence to analyze correlation between discharge magnitude and acoustic signal in insulation oil. We fabricated a decoupler and an amplifier to measure acoustic signals produced by PD. The amplifier has the gain of 40 dB and the frequency bandwidth of 1.6 kHz~1.6 MHz. After a comparative calibration by a standard pulse generator and a coupling capacitor, we analyzed the propagation characteristics of acoustic signals in insulation oil as a function of distance.

• Journal of Advanced Marine Engineering and Technology
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• v.38 no.9
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• pp.1119-1124
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• 2014

This paper describes the emergency situation which occurs in Drilling Rig power system. Especially, we focused on power system transient characteristics on propulsion motor load and generator elimination situation in Drilling Rig operation. We performed numerical simulation and analyzed the result for power system transient stability characteristics on each condition for excitation system and governor control system using ETAP (Electrical Transient Analysis Program).

• Journal of Advanced Marine Engineering and Technology
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• v.16 no.4
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• pp.50-59
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• 1992

The paper presents a digital speed control approach of induction motor systems by using a digital servo control method and a well-known second order differential equation as model. The basic concept of using the modeling equation stated in the above is induced from the control theory stand point such that we can describe usually the motor system connected by inverter, generator and load etc, just as a mechanical system to be controlled. The concept does not demand us the complicated vector-based modeling equation adopted in the traditional methods for the speed control of induction motor. Futhermore, the proposed speed control system can be treated as a single input and single output system. The effectiveness of the servo control system obtained by the above-mentioned design concept is illustrated by the experimental results in the presence of both step reference changes and load variations. It is observed from the experimental results that the steady state-error of the experimental set up becomes zero after some regulation time and the induction motor system is robust in spite of reference signal changes and load variations.

• Journal of Advanced Marine Engineering and Technology
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• v.18 no.1
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• pp.101-113
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• 1994

This research has presented and experimental investigation on the characteristics of turbulent wake past a rectanular cylinder, according to various width/height ratio such as B/H=2.0, 2.79, 3.0, and 4.0 in a uniform shear flow. In order to perform this study, a special shear flow generator which produces the uniform shear flow has been designed and manufactured. It is found that the characteristics of the wake in a uniform shear flow are quite different from those of a uniform flow and vary with shear rate. And also, the formation of regular vortex structure is concerned with shear rate.

• Journal of Advanced Marine Engineering and Technology
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• v.24 no.3
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• pp.106-112
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• 2000

Since the oil crisis, we have been concerned about the energy saving techniques of electric generating systems. As a part of the effort to save energy, automatic electric load sharing device was developed. Usually, ship's electric generating system consists of two or three sets of generator. And, electric generating system is operated as single or parallel operation mode according to the demanded electric power. Therefore, it is important to investigate generators operating mode for the supply of required electric power in the ship in order to decrease the operating cost. So, this paper suggests the method to solve the optimal electric load distribution problem by dynamic programming. And, this thesis indicates that the proposed method is superior to the lagrange multiplier's method in obtaining optimal load distribution solution in the ship's electric generating system.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2002.05a
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• pp.233-238
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• 2002

This paper propose the construction of fault diagnosis engine for diesel generator engine and rule inference method to induce rule for fuzzy inference from the monitored data of diesel engine. The proposed fault diagnosis system is constructed the Malfunction Diagnosis Engine(MDE) and Hierarchy of Malfunction Hypotheses(HME), It is Proposed the rule reduction method of knowledge base for concerning data among the various analog data.

• Journal of Advanced Marine Engineering and Technology
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• v.33 no.3
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• pp.395-402
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• 2009

This paper presents the newly developed Pareto-based multi-objective Bees Algorithm with weighted sum technique for solving a power system multi-objective nonlinear optimization problem. Specifically, the Pareto-based Bees Algorithm with memorized zone has been developed to alleviate both difficulties from classical techniques and intelligent techniques for multi-objective problems (MOP) and successfully applied to an Environmental/Economic (electric power) dispatch (EED) problem. This multi-objective Bees Algorithm has been examined and applied to the standard IEEE 30-bus six-generator test system. Simulation results have been compared to those obtained using other approaches. The comparison shows the potential and effectiveness of the proposed Bees Algorithm for solving the multi-objective EED problem.

• Journal of Advanced Marine Engineering and Technology
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• v.28 no.5
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• pp.746-753
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• 2004

In this paper, the Power Management System(PMS) which based on a decision making system according to power strategy is proposed and implemented. PMS is designed to have functions of power monitoring. controlling, synchronizing load sharing and monitoring of driving engine, etc. PMS consists of the internet communication system(ICS). Remote Management System(RMS) and Sensor Driver System (SDS) ICS transmits the monitoring and supervisory data via Internet to Remote Management System(RMS) in real-time SDS detects various power system data on local generator and utility via I/O interface system. I/O interface system receives various status data and outputs control signals. Implemented PMS is tested with dummy signal to verify proposed functions and shows good results. For future study implemented PMS will be tested under real load condition to merchandize.

• Journal of Advanced Marine Engineering and Technology
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• v.28 no.2
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• pp.367-375
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• 2004

We have developed a highly efficient boiler system using the 2,600cc Diesel engine. In this system, the co-generation concept is utilized in that the electric power is produced by the generator connected to the engine, and waste heat is recovered from both the exhaust gases and the engine itself by the shell-and-tube heat exchangers. The heat exchanger connected to the engine outlet is specially designed such that it not only recovers waste heat effectively from the exhaust gases, but significantly reduces an engine noise. It is found that the total efficiency(thermal efficiency plus electric power generation efficiency) of this system reaches maximum 96.3％ which is about 15％ higher than the typical Diesel engine boiler system currently being used worldwide.

• Journal of Advanced Marine Engineering and Technology
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• v.21 no.4
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• pp.356-363
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• 1997

Many research works have been carried out to investigate the factors governing the performance of diesel engine. The area of the study has been focused on reducing both of NOx and smoke because of many difficulties to reduce them simultaneously in diesel engines. One of the efforts is an application of EGR technology to reduce NOx emission, which is very effective, but increases other emissions and makes fuel economy worse. In order to solve the problem, EGR is employed with water emulsified fuel and tested in this paper. Emulsified fuel is produced by centrifugal mixer and the amount of water is controlled by water injector and pulse generator, and EGR rate is controlled with 6-step control valve. The chamber pressure, fuel consumption and emissions are measured with various values of both EGR and water mixing rate, The results show that NOx emission is reduced much rather and smoke is also reduced simultaneously.