• KEPCO Journal on Electric Power and Energy
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• v.2 no.3
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• pp.403-407
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• 2016

In general, drum-type boilers are designed for base load duty and applied under constant pressure operation mode. Recently, however conditions often occur that even drum-type boilers have to operate at partial load conditions. A feasibility study on adopting the sliding pressure operation for drum-type boiler was conducted, and corresponding performance changes and effects on the equipment were analyzed by utilizing a process simulation model. As a result, the conclusion was reached that drum type boilers are able to adopt the sliding pressure operation and can improve of net efficiency at part load operation in spite of the Rankine cycle efficiency reduction due to the decreases in main steam pressure. Because of thank to improvement of high pressure turbine stage-1 internal efficiency and power savings of boiler feed water pump. The sliding pressure operation is advantageous in terms of stress level relief for boiler tube as well as maintaining the rating steam temperature at part load condition. However, cautions are required because the drum boilers have poor dynamic response characteristics which may get worse during the sliding pressure operation.

• Journal of the Korean Society for Precision Engineering
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• v.19 no.12
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• pp.70-77
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• 2002

Necessity of the tole-operation has been increased in many fields. Since the Internet is inexpensive and available all over the world, it is a strong candidate for the transmission media of the tole-operation. However, the Internet has random time delays that may cause instability in the system especially if the tole -operation is bilateral. In the past few years many attempts have been made to overcome the random time delay, So far, they are still insufficient in terms of performance. The ‘Variable holding time’ is introduced to improve the performance of the ‘Event based tole-operation’ which controls a system with a non-time action reference. By holding each event for proper time, the system can quickly respond and be stabilized. The proper holding time should be selected based on the characteristics of the task that the system performs. The factors that reflect those characteristics are investigated. The fuzzy logic is employed to obtain the proper holding time for each event while the tole-operation system is in operation. The experimental results presented in this paper verify effectiveness of the proposed method.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.32 no.1
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• pp.44-51
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• 2009

A bonded warehouse is the warehouse located in bonded area. It functions not only as a general warehouse but also as a place for managing the work related to import and export bonded goods. As a general warehouse, it uses the rack system to store the goods and the folk lift truck to move the unitized goods. The operation of the storing system closely related to the efficiency of space uses in a warehouse and vehicle working. Thus, vehicle performance measured in distance units in the ware-house could be used as one of the key performance measure in warehouse system. This paper focuses on the operation efficiency of the bonded warehouse which uses rack system for the storing and the folk lift truck for moving goods. The method of load allocation for balancing the rack uses and vehicle operation for maximizing efficiency are the specific concerns in this paper. The simulation study is conducted to find a policy for efficient vehicle operation based on balanced rack utilization, and the favorable result for the system operation would lead the usable proposal in vehicle operation.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.16 no.5
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• pp.49-59
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• 2021

This study researched the relationship of effect of management awareness of corporate members, system buildup and strategic operation on corporate performance through industry-university collaboration networking. The result of the study are as follows. First, as the importance of industry-university collaboration, system buildup networking was proved to provide the greatest influence on the corporate performance. Second, it presents to form the bond of sympathy with members on corporate management which is built through industry-university collabora-tion. Third is the importance of strategic operation. Strategic operation was prove to have high influence on corporate performance. Fourth is to prove the relationship between system buildup and strategic operation of industry-university collaboration networ- king. The system buildup provides an important impact on corporate strategic operation. Fifth is the system buildup through management awareness by through industry-university collaboration. Lastly, the relationship between management awareness and corporate performance was found to be significant. Management awareness of members can be presented as an important variable on corporate performance. This study is to present the fact that it is important to secure competitiveness of small and medium-sized businesses, to develop a way for creative improvement and to secure a way for strengthening the competitiveness, and to strengthen the corporate competitiveness through reinforcement of industry- university collaboration networking.

• Journal of the East Asian Society of Dietary Life
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• v.23 no.6
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• pp.850-861
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• 2013

This study aimed at investigating any differences perceived between the contractor and the contractee based on an importance-performance analysis (IPA) of foodservice quality attributes. Questionnaires were distributed to 200 personnel concerned in the Busan, Ulsan and Kyungnam areas and a total of 134 valid responses were used for analysis. Of the 23 foodservice quality attributes, the factors of 'food quality', 'employee service', 'hygiene and safety', 'customer orientation' and 'operation quality' were induced from a scale purification process through the exploratory factor analysis. The level of importance (p<0.01) of the 'hygiene and safety' factor and 'employee service' factor was not found to be significantly different between the groups. In the level of performance, the factors of 'food service', 'employee service', 'customer orientation' and 'operation quality' were found to be perceived significantly lower than expected by the contractor group. In the importance level, 'food quality', 'employee service', 'hygiene and safety', 'customer orientation' and 'operation quality' were rated by the contractor as 4.03, 4.30, 4.27, 4.01 and 4.12 points, respectively. In contrast, in the performance level, perceived 'food quality', 'employee service', 'hygiene and safety', 'customer orientation' and 'operation quality' were evaluated as 3.57, 3.94, 4.06, 3.83 and 3.95 points, respectively.

• Journal of Energy Engineering
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• v.17 no.3
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• pp.161-166
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• 2008

The purpose of this study is to apprehend the behavior of exhaust gas flow from gas turbine during part load operation in Heat Recovery Steam Generator. As a first step of this work, internal flow characteristics according to HRSG types were examined by CFD analysis. Next step, tube temperature according to gas turbine 53% and 100% load conditions were calculated by results of CFD and those were compared with temperature data gathered from real plant. Finally, thermal performance due to part load operation was calculated to estimate the influence of heat transfer in superheater. In addition, new type of device is suggested to eliminate the uneven temperature distribution of tubes during part load operation.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.67 no.11
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• pp.1549-1554
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• 2018

Recently the design of railway systems have been performed, based on the analysis of operational conditions and service targets, it is to optimize the effectiveness and efficiency of system operation. Many RAMS requirements have been developed to transform operation conditions into system design characteristics. However, our railway industry has not actived the application of RAMS into system design performance. According to short of RAMS application, many technologies that have been developed are not only applied the existing systems that is operating, but also have not succeed to apply for new systems. In order to design the effective and efficient railway systems that are optimized to operation conditions and service targets, a systems approach and RAMS management are necessary in railway development, operation and maintenance. Therefore, in this study, the RAMS performance requirement design methods are discussed. the allocation methods from system level to each devices of subsystems.

• Proceedings of the KSR Conference
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• 2008.06a
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• pp.684-690
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• 2008

LRT System Application Project is performed for the purpose of technical advancement and stabilization of K-AGT system from the viewpoint of practical use and commercialization. For those purpose, the performance test and evaluation procedure for signaling system have been developed, including the scheme of verifying the performance and function of signaling system under driverless multiple train operation environment. In this paper, multiple train operation scheme in K-AGT test line is presented. Test schemes for maintaining the safety distance between trains, operation scenario considering shunting and turning of train, and dia operation schemes in test line are reviewed while researching test vehicle features, route condition and running pattern. Additional equipments for testing each scheme are also reviewed.

• Proceedings of the KIEE Conference
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• 2000.07b
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• pp.687-689
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• 2000

Molten Carbonate Fuel Cell (MCFC) with high electrical efficiency and low environmental effect has been developed for the commercial application of power generation fields. Recently we have built a 25 kW molten carbonate fuel cell power generation system and tested it. The MCFC system is composed of diverse peripheral units such as reformer, pre-heater, water purifier. electrical loader, gas supplier, and recycling systems. The stack itself was made of 40 cells of $6.000 cm^2$ area each. The stack showed an output of 28.6 kW power and a reliable performance at atmospheric operation. while in pressurized operation the stack showed an output 25.6 kW lower than the atmospheric operation. The reason of lower performance of pressurized operation was caused from a gas cross over shown in few cells in the stack.

• International Journal of Railway
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• v.4 no.4
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• pp.81-85
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• 2011

This paper discusses the development of a generic train operation model from a set of Korean Urban Transit Regulations such as Regulation for Train Operation of Urban Transit, Regulation for Safety Requirements of Urban Transit and so on. It is to communicate with various stakeholders on urban transit system, and to elicit copious requirements in performance of the urban transit train operation based on the model.