• The Transactions of The Korean Institute of Electrical Engineers
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• v.66 no.8
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• pp.1172-1180
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• 2017

This study analyzed competition in peak load plants between CCGT and GT instead of competition between base and peak load plants like in previous studies. In common overseas power markets, CCGT and GT claim certain market shares as peak load plants with the latter boasting a high utilization rate as reserve plants. In South Korea, however, there has been no introduction of GT in the market that opened in 2001 with no analysis cases of GT's economy as a peak load plant. The current power market of South Korea is run on the cost-based pool, which allows for no price spikes. Since the capacity payment criteria for compensations for missing money are set based on GT generators, the power market uses GT generators as marginal plants. The purposes of this study were to analyze the competitive edge of GT generators as peak load plants in the domestic power market of South Korea and identify the causes of GT's failure in market entry, thus assessing the adequacy of market signals in the domestic power market.

• Journal of Advanced Marine Engineering and Technology
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• v.35 no.6
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• pp.779-785
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• 2011

Prediction of the transient pressure variations and performance parameters has been carried out for an SI engine using one of commercial software, GT-POWER. Various models were applied for the calculation of properties of the plenum chamber, exhaust manifold and catalytic convertor which are very important components included in the intake and exhaust systems.

• Journal of Advanced Marine Engineering and Technology
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• v.36 no.8
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• pp.1050-1060
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• 2012

As an approach to high-efficiency of SOFC system, SOFC/GT Hybrid system is effective. However, if the output size of the system belongs to the marine class of dozens MWs, the introduction of the cooling system of GT system, which is used as sub-system, makes its related devices complicated and also makes its control difficult. Accordingly, for the marine use, SOFC/GT (non-cooling)Hybrid system looks more suitable than SOFC/GT(cooling)Hybrid system. This study established the SOFC/GT (non-cooling)Hybrid system, and examined the operating temperature & current density of the stack for the system, pressure ratio of the gas turbine, the influence of TIT(Turbine Inlet Temperature) on system performance, etc. through the simulation process. Through this research process, this study was able to confirm that electrical efficiency rises in spite of the increase in the required power for the air compressor, and there exists a limited range of temperatures for operation in TIT.

• Journal of Advanced Marine Engineering and Technology
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• v.36 no.5
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• pp.586-594
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• 2012

A future type ship power system requires both economic and eco-friendliness. That is, this should be reduced the discharge quantity of air pollutants and green-house gases as well as have high energy efficiency. Recently, gas turbines have been realized a lot of technical development in terms of efficiency and safety, and are widening the example of their adoption to a GT/ST hybrid system in a power plant as well as an aviation use. This paper reviewed the performance characteristics of a GT/ST hybrid system of several ten MW class, not large capacity, with a simulation in order to evaluate the possibility of a GT/ST hybrid system for ships. The reviewed GT/ST hybrid system has maximum 49 % efficiency, has the highest efficiency point for TIT, and has a 70~75 % and 25~30 % load ratio for a gas turbine and a steam turbine respectively.

• Journal of ILASS-Korea
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• v.23 no.1
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• pp.1-8
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• 2018

In this study, the effects of variation in cam phasing and valve lift of exhaust valves by using Cam-in-Cam system on combustion and emission characteristics for diesel engine were investigated under GT-POWER simulation environment. This paper showed analytic result of combustion characteristics and diesel exhaust valve's control with GT-Power 1-D detail model. As a result, it was found that volumetric efficiency and IMEP were decreased as the exhaust valve opening and closing timing is advanced due to its internal EGR effects. Also, it was found that NOx emission were decreased as EVC timing was retarded. These show that the retarding the exhaust valve closing and opening while keeping the duration at constant can be effective for controlling AFR and mixing rate in diffusion combustion of diesel engine.

• Proceedings of the KIEE Conference
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• 2004.11d
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• pp.83-88
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• 2004

As the electric system is getting larger to meet the increasing demand for electric power, the rating of power apparatus is becoming inevitably higher in its working voltage and larger in its capacity. According to KEPCO reports, power transformers in the KEPCO system have undergone troubles such as winding short insulation breakdowns every year since 1981. the cause of this troubles were high one line grounding fault currents in KEPCO systems that had direct grounding systems. KEPCO has installed the NGR(neutral grounding reactor) to lower this fault current and reduced winding short insulation breakdowns in power transformers. But when a circuit breaker opened a no load bus, some trips of circuit breakers for protecting transformer have occurred by mal-operation of 59GT(overvoltage ground relay) that detect disconnection of NGR. Therefore, in this paper, we analyzed the cause and examined the effect of time delav circuit to prevent wrong operation of 59GT.

• Journal of Advanced Marine Engineering and Technology
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• v.36 no.1
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• pp.40-50
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• 2012

The electrification of the waste heat of stack is necessary to enhance the efficiency of fuel cell system. For this purpose, the hybrid SOFC/GT/ST system is suitable. The purpose of this work is to predict the performance of methane fueled SOFC/GT/ST hybrid power system and to analyze the influence of operating temperature of stack, current density of stack, and gas turbine pressure ratio. According to the analysis, it is proved that the SOFC/GT/ST hybrid system suppress the rapid decrease in efficiency and lead to the significant improvement of efficiency as compared with SOFC system.

• Journal of Advanced Marine Engineering and Technology
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• v.32 no.2
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• pp.256-261
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• 2008

The purpose of this study is to propose practicable configurations against Rapid Load Down like propeller racing of ships which have been using SOFC/GT hybrid system on board. This paper suggests four kinds of countermeasures against propeller racing. The types A and B keep a fixed load of SOFC and save a surplus electric power to a storage system. In types of C and D, the load of SOFC is changed with the propeller racing. The best desirable countermeasure for Rapid Load Down depends upon the size of the ship, the propulsion power, and the characteristics of the engine system.

• Journal of Korean Physical Therapy Science
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• v.17 no.1_2
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• pp.77-83
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• 2010

Background: In recent days, Taping has introduced developing to improve our muscle power and sustaining power more than a fixed idea that taping only functions for muscles and protection of the articulation. Method: This study were conducting in two weeks - 2009 September 1 to September 14 - investigating at random 24 normal adults in H university located at Jinju Korea and the result of experimentation how the application of kinesio taping and Bang-gue taping(B-GT) to rectus abdominal muscle has an effect on the improvement of abdominal muscle strength. Results: the following conclusion was drawn up: 1. As a result of each experience man and woman with abdominal muscle strength, each experience all man and woman with abdominal muscle strength(p=0.01) came out to have interrelation difference. 2. As a result of comparing B-GT with age-abdominal muscle strength, B-GT(p=0.02) came out to have interrelation difference. 3. As a result of comparing after before kinesio taping and after before B-GT with abdominal muscle strength, after before kinesio taping and after before B-GT(p=0.00) came out to have interrelation difference. Also, as a result of comparing after kinesio B-GT, after kinesio B-GT(p=0.03) came out to have interrelation difference. Conclusion: As mentioned above, this study showed how the application of kinesio taping and B-GT to affected the improvement of abdominal muscle strength.

• Journal of Advanced Marine Engineering and Technology
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• v.33 no.4
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• pp.484-496
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• 2009

The strengthened regulations for atmospheric emissions from ships like MARPOL Annex VI have caused a necessity of new, alternative power system in ships for the low pollutant emissions and the high energy efficiency. This paper attempts to investigate the configuration of SOFC/GT hybrid power system for LNG tanker taking into account the safety and to analyze the influence of design parameters on the system performance. The simulation results provide the basic data for the design and efficiency improvement of SOFC/GT hybrid system and indicate the guidelines for the safe system operation.