• Publications of The Korean Astronomical Society
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• v.26 no.4
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• pp.159-168
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• 2011

We constructed two test server systems for KMTNet data management. One is the photometry database server which is optimized for stable operation, and the other is the photometric data process server which is optimized for fast I/O between devices. The performances of servers and data storage units were tested using various methods. Database upload was also checked using five different methods. From tests, we concluded that the most efficient method to upload photometric data processing results to database is the use of three nodes with job scheduler under the InnoDB engine. In this study we provide the test results for prototype servers for KMTNet data management.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.1B
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• pp.34-41
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• 2002

In this paper, the algorithms increase the capacity of the forward link channel are studied in the DS-CDMA mobile communication system with the technology of transmit antenna array. Through of the implementation of the test bed with PC and DSP boards, the hardware implementation and optimization of the algorithms, the operation scenario and architecture of the test bed, are considered. In addition, the performance analyses are achieved about the execution time of the algorithms.

• Proceedings of the KIEE Conference
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• 2001.07c
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• pp.1811-1813
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• 2001

In order to obtain the useful data for quality control of the pole transformer and supply the stable electric power in distribution line, The evaluation of performance for low-loss pole transformer had been performed for new products and ones under operation for several years in distribution line. As the results, we found that the rate of fail were very high in gaskette, short-circuit strength and temperature-rise test, especially 48 percent in gaskette test.

• 유체기계공업학회:학술대회논문집
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• 2006.08a
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• pp.313-316
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• 2006

As Decentralized Generation(DG) becomes more reliable and economically feasible, it is expected that a higher application of DG units would be interconnected to the existing grids. This new market penetration of DG technologies is linked to a large number of factors like technologies costs and performances, interconnection issues, safety, market regulations, environmental issues or grid connection constrains. Korea Electric Power Corporation (KEPCO) has researched performance characteristics of the 60k W class 1) basic start-up & shutdown operation analysis 2) interconnection test 3) MGT -absorption chiller-heater system in the local condition. Variations of heat recovery from exhaust gas has measured according to micro gas turbine output of 15, 30, 45, 60kW. From those results, the performance of the MGT-absorption chiller/heater system has been evaluated. The suggested strategy and experience for the evaluation of the distributed generation will be used for the introduction of other distributed generation technologies into the grid in the future.

• Proceedings of the KSME Conference
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• 2001.11b
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• pp.83-88
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• 2001

This paper presents modelling and analyzing method of centrifugal chiller which has a rated capacity of 200 RT(703 kW) through on-site performance test. Field data of chiller installed in the clean-room building of KIST have been collected, Simple models were developed for predicting the heat exchangers and system performances by regression of chiller operation data during 5 days in August. The models proposed here account for the effect of variations of cooling capacity, temperatures and flow rates of secondary fluids. The models are consistent with real performance data from June to September within ${\pm}5%$ error. The COP of centrifugal chiller are estimated under the standard rating conditions and reduced mass flow rate of chilled and cooling water.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1992.10a
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• pp.204-208
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• 1992

The purpose of this research is to construct the experimental test set-ups and establish a series of performance test program for the domestically developed fluid couplings, and to provide a software to store and utilize these experimental data which can be used to improve the performance of the fluid coupling and solve on the job problems confronted in operation. The performance test consists of taking measurement of torque rpm and efficiency of the fluid coupling for three different amount of working fluid inside with various loads to the output shaft and finally investigating the torque rpm and efficiency characteristics of the fluid coupling with respect to these parameters. The results of this study can contribute valuable references tot the development of variable speed fluid coupling and torque converter currently pursued by the domestic industry.

• Journal of the Korean Society for Precision Engineering
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• v.24 no.2 s.191
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• pp.47-57
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• 2007

The vibration environment essentially companied by vehicle operation on the road is determined by the shape of road surface, which is called profile. In general, the profile and severity of unpaved road is an important issue in the reliability of durability test for vehicles. In order to maintain severity of unpaved road, it is necessary to develop profilometer system. We developed profilometer system which is composed of data processing computer, power unit, air compressor and sensors. This paper focuses on the severity management of unpaved test courses using neural networks. This paper presents the maintenance range for cross-country course in CPG(Chang-won Proving Ground) and the evaluation of similarity degree between unpaved roads.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2007.11a
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• pp.165-169
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• 2007

Qualification test range for Lox/Kerosene gas generator cyle liquid rocket engine was determined by considering engine dispersion and flight inlet conditions. With various pump characteristics, the operation range of components and system was investigated through dispersion analysis. The variation of engine performance shows opposite trends in calibration and dispersion.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2006.04a
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• pp.3-9
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• 2006

Among many fabrication methods of composite materials, filament winding is the most effective method for fabricating axis-symmetric structures such as pressure tanks and pipes. Filament wound pressure tanks are under high internal pressure during the operation and it has the complexity in damage mechanisms and failure modes. Fiber optic sensors, especially FBG sensors can be easily embedded into the composite structures contrary to conventional electric strain gages (ESGs). In addition, many FBG sensors can be multiplexed in single optical fiber using wavelength division multiplexing (WDM) techniques. In this paper, we fabricated several filament wound pressure tanks with embedded FBG sensors and conducted some kinds of experiments such as an impact test, a bending test, and a thermal cycling test. From the experimental results, it was successfully demonstrated that FBG sensors are very appropriate to composite structures fabricated by filament winding process even though they are embedded into composites by multiplexing.

• Proceedings of the KSR Conference
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• 2007.11a
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• pp.453-457
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• 2007

AGT system is a kind of light railway train. AGT system use of concrete track and rubber tire, so it can be reduce the noise and vibration, compare to the normal train system. And, the dynamic responses of normal bridge are influenced by the dynamic characteristics of bridge, the speed of vehicle and the surface roughness of railway. But the AGT system bridge is influenced not only the above facts but also the guiderail unevenness, because, AGT vehicle steered by guiderail. So, in this study, optimized service condition is suggested for the design and operation of AGT system, by the means of experimental study. The experiments are executed for PSC bridge with length of 30m, at the AGT test line in Kyongsan. The test results are compared and investigated according to the prominence. In the test result, the guiderail prominence influenced on the dynamic response of bridge. It shows a increase as compared with no guiderail prominence in the dynamic response value acceleration, displacement, stain.