• Proceedings of the Korean Society of Marine Engineers Conference
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• 2002.05a
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• pp.267-272
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• 2002

The electric heat pump requiring HCFCs as a refrigerant has been for most residential air-conditioners in Korea. They cause a surge up electric power demand during summer. Moreover, the use of HCFCs and HFCs causes a serious problem to the global environment such as global warming and ozone layer destruction. An absorption chiller and heater could solve such problems. It was built and tested for analyzing the performance of the absorption chiller/heater. Experiment was done with a 1.5RT household absorption chiller and heater. It was experimented that the cooling capacity, gas capacity, COP were researched by the temperature of cooling water. The change of the cooling water temperature have effect the temperature(or pressure) of the parts on absorption chiller The result of the change of the cooling water temperature have the effects of the absorption chillers. This data will help to operate the household absorption chiller and heater.

• Journal of Advanced Marine Engineering and Technology
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• v.33 no.7
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• pp.1068-1074
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• 2009

This paper describes a study for the buoy which should be operated by a stand-alone power system. The field of this study is related to a power system operated by two batteries which depends on the load power. The fluctuation of the voltages makes the life cycle of the battery shorten. The control algorithm has been proposed for reducing the voltage pulsation of the battery by operation strategy according to using purpose such as main or sub power supply system. The power system with battery is separated two parts and this has been proved through a simulation and a sea experiment. In order for the experiment to use a wireless monitoring system has been installed in buoy. This paper shows an excellent test result of wireless monitoring system for buoy.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.20 no.5
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• pp.570-575
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• 2011

Ultrasonic metal welder is consisted of power supply, transducer, booster, and horn. Precise designing is required since each parts' shape, length and mass can affect driving frequency and vibration mode. This paper analyzed Cu sheet deposition characteristics using ultrasonic metal welder and tension tester. A horn suitable for 40,000Hz was attached to the ultrasonic metal welder in order to weld Cu plates. The Cu sheet welding was done with different amplitude, pressure, and welding time, and its maximum tension was measured with tension tester. Maximum tension of 153.87N was obtained when the pressure was 2.0bar, amplitude was 80%, and welding time was 0.30s. Therefore, excessive welding condition negatively influences maximum tension measurement result.

• The Journal of Sustainable Design and Educational Environment Research
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• v.10 no.3
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• pp.9-16
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• 2011

As a result of rapid aging speed in our society, many problems related to elderly people have happened in many parts of our society. Among them, supply for elderly facilities is one of the biggest problems. In downtown areas, despit of the high demand for elderly facilities, there is not enough supplement of them due to the lack of real estates. Considering the situations above, this study proposes multi generation complex which combining the school and elderly welfare facility. This combination not only brings financial benefits but also has positive effects on cultural exchanges between generations.

• Proceedings of the KSR Conference
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• 2010.06a
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• pp.1360-1365
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• 2010

The TBO of main unit of propulsion control devices on high-speed railway vehicles proposed by the makers is appropriated 10 years cycle, but the maintenance of internal device are proceeding before coming to the particular period of time. In the Future, increasing of the failure probability occurred by increasing train service and obtaining spare parts are predicted that it would be difficult. the propulsion control devices develop is needed in other to the ease maintenance, cost savings and ensuring related domestic technologies when considering operating on long term of high-speed railway vehicles. In this paper, we proposed development a way that current-controlled type propulsion control devices using the newest power semiconductors which is easy to supply and demand through identifying performance and characteristics of existing current-controlled type propulsion control devices of high-speed railway vehicles.

• Proceedings of the KSR Conference
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• 2010.06a
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• pp.25-29
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• 2010

Safety of railroad is result of reliability which is received from test & evaluation of system. Railroad system is consisted of various sub system such as vehicle, supply of electric power, signal, communication, rail track construction, operation. To secure safety of railroad, evaluation about parts, assembly, sub system, whole system etc.. that compose railroad is essential. In this paper, I wish to describe for results that analyze korean tilting vehicle's derailment coefficient developed by national research achievement. Confirmed that is possible even if speed up, curved line department running speed that estimate korean tilting vehicle's running safety in curved line track of Jungang Line about 20 km/h than present operating speed.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.33 no.3
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• pp.10-21
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• 2010

Promotion system can be used as strategical management weapon to enhance the sales power. Planned order system has some similarities with promotion system to create purchasing power and to supply the service parts with low price on purpose. The only difference is whether it is prearranged event or not. The effectiveness of forecasting has increased with normal state of ordering process. However, the accuracy of forecasting has diminished with irregular state of ordering, such as demand occurrences by unexpected climate change or intended planned order by the company. A planned order system is examined through the process of computing the effectiveness on the basis of forecasting in this paper. And it is suggested that how to increase the accuracy of forecasting capability under the planned order system.

• IE interfaces
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• v.18 no.3
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• pp.308-316
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• 2005

Delayed repair to the failure of weapon system can cause enormous damages to military operation. Various materials like diagnostic equipment, general and special tools, technical manuals(maintenance manual and illustrated parts breakdown) and drawing documents are required for maintenance. For existing weapon systems the distributed environment of these various materials reduces the maintenance effectiveness of maintenance crew. In this paper, to provide the information of maintenance procedures and supply to the maintenance crew we develope a digital interactive electronic technical manual of the technical documents which can be used easily in computer through question and answer method and improve maintenance effectiveness and minimized repairing time.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.33 no.3
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• pp.185-189
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• 2009

Focused ion beam system was designed, which includes LMIS, electrostatic lens and high voltage power supply. Control program is updated for high speed image processing. The details of vibration-free vacuum system and other important electrical parts were trouble-shooted for appropriately controlling high acceleration voltages.

• The Transactions of the Korean Institute of Power Electronics
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• v.5 no.4
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• pp.327-334
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• 2000

In this paper, the circuit model using circuit averaging method for full bridge for full bridge converter is suggested. This model can represent the physical characteristics of converter circuits appropriately. At most of high capacity DC-DC converter application parts, full bridge converter is adapted for main circuit of power supply. Design and analysis of full bridge converter is no trouble with circuit model. The validity of circuit model is verified through computer simulation and practical welding experiment of welding machine with full bridge converted model.