• Journal of Information Technology Services
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• v.7 no.1
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• pp.195-204
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• 2008

As the dependency to network system and demands of efficient storage systems rapidly grows in every networking filed, the current trends initiated by explosive networked data grow due to the wide-spread of internet multimedia data and internet requires a paradigm shift from computing-centric to data-centric in storage systems. Furthermore, the new environment of file systems such as SAN(Storage Area Network) is adopted to the existing storage paradigm for providing high availability and efficient data access. We describe the design issues and system components of $SANique^{TM}$, which is the cluster file system based on SAN environment. We, especially, present the comparative results of performance analysis for the intensive I/O test by using the DBMSs that are operated at the top of cluster file system $SANique^{TM}$, EXT3 and NFS respectively.

• Journal of the Korean Society for Railway
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• v.10 no.6
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• pp.800-805
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• 2007

The critical speed of railway bogie is very important in terms of the verification of the vehicle design procedure and safety. The dynamic performance of bogie is tested on the railway roller rig in a laboratory in place of field testing on track. But, the testing on the full scale roller rig caused many problems relating to test costs, test time and has the difficulty in test condition setup. To overcome these problems, scaled models were used in the filed of railway vehicle design and test. In this paper, we have studied the critical speed of scaled bogie model. We have made the 1/5 scaled bogie, the scaled roller rig and analyzed the critical speed of the scaled bogie through the numerical simulation and running test of the scaled bogie. We have confirmed that the analysis results of the critical speed correspond with the test results.

• Proceedings of the Korean Geotechical Society Conference
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• 2003.03a
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• pp.385-392
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• 2003

Traditional forms of river and coastal structures have become very expensive to build and maintain, because of the shortage of natural rock. Geotextile tubes hydraulically or mechanically filled with dredged materials have been applied in hydraulic and coastal engineering in recent years(shore protection structure, detached breakwater, groins and jetty). Recently, new preliminary design criteria supported by model and prototype tests, and some stability analysis calculations have been studied. In this study, the numerical analysis was performed to investigate the behavior of geotextile tube with various properties of geotextile and hydraulic pumping conditions. Numerical analysis was executed to compare with the results from the large-scale field model tests, and also compared the results of 2-D plane strain analysis and 3-D FEM analysis. A geotextile tube was modeled using the commercial finite element analysis program ABAQUS and the one-quarter of tube was modeled. Behavior of geotextile tube during the hydraulic pumping procedure was analyzed by comparing the large-scale field model test and numerical analysis. The shape variation and maximum tube height between the numerical analysis results and large-scale filed test results are turned out to be a good agreement.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.2405-2408
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• 2011

In recent time, the cause analysis and the reduction of the track irregularity have become the most important issue in the ballasted track on the high-speed railway bridge. This is because that the frequency of the maintenance work at the bridge expansion joint zone is on the rise. The track irregularity on the railway bridge starts at the end of the bridge-deck and spreads along the bridge. Due to the dynamic vibration and the thermal expansion of the bridge, the compaction of the ballast gravel on the bridge expansion joint zone become loose and then the progress of the track irregularity result from the train-induced dynamic impact is accelerating further. Among the several options for reducing the track irregularity on the bridge expansion joint zone, the application and efficiency of the zero longitudinal restraint(ZLR) and tied sleeper are investigated in this paper. Field test construction has been conducted, then the progress of the track irregularity and the frequency of the maintenance work are analyzed before and after the filed test construction. Of the two methods, it is shown that the installation of the ZLR seems to be better than the tied sleeper.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.2125-2128
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• 2011

The continuous welded rail(CWR) track without the rail expansion joint has many advantages over the conventional track in a variety of fields including the speed-up and the ride comport. However, due to the excessive axial force in the CWR and the track-bridge interactive behavior, inevitably, the rail expansion joint must be installed at the vulnerable zone such as the bridge end zone, etc. In this rail expansion joint zone, the frequency of the maintenance work to repair the track irregularity is on the rise. This is because that the creep of the sleeper is occurred in the moveable zone of the rail expansion joint. In this study, among the several options for reducing the track irregularity on the rail expansion joint zone, the application and efficiency of the tied sleeper is investigated. Field test construction has been conducted, then the progress of the track irregularity and the frequency of the maintenance work are analyzed before and after the filed test construction.

• Proceedings of the IEEK Conference
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• 2004.06b
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• pp.379-382
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• 2004

In this paper we fabricated a test panel for AMOLED on glass and PET substrate. The test panel consisted of the various size of OTFTs and OLEDs and the current driving capability of OTFTs for OLEDs has been investigated. OTFTs were made of the inverted staggered structure and employed polyvinylphenol (PVP) as the gate insulator and pentacene thin film as the active layer. The OTFTs produced the filed effect mobility of $0.3 cm^2/V.sec$ and on/off current ratio of $10^5$. OLEDs consisted of TPD for HTL and Alq3 for EML with 35nm thick, generating green monochrome light. We found that OTFT with channel length of 70${\mu}m$ and channel width of over 3.5mm provided the sufficient current to OLED to generate the luminescence of $0.3Cd/m^2$.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.10
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• pp.3898-3904
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• 2010

In order to analyze the transient characteristics for distributed generation located with the secondary feeders, this paper constructs a Distributed Generations Filed Test Center which can produce transient characteristics such as voltage sag, swell, interruption, harmonic and so on. And also this paper proposes the test results for the interconnection of distributed generations. The results show the effectiveness for the utility technical guidelines for distributed generations with the secondary feeders.

• Journal of the Korean Society of Clothing and Textiles
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• v.37 no.7
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• pp.864-873
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• 2013

This study analyzed the correlation between the sources of the complaints and various factors such as gender, garment type, fabric type, textile material and washing methods for products. This survey utilized a total of 2,609 consumer apparel product complaint cases filed with the Korea Consumer Agency between 1997 and 2009. In regards to consumer liability: it was found that more incidents of failures due to carelessness were reported among men's clothes, knitted garments, cotton clothes, polyester clothes, wool blend clothes, pants, shirts, sportswear, and laundry only clothes. In regards to dry cleaner's liability: women's goods, woven clothes, silk clothes, cotton blend clothes, jackets, shirts and hanbok, and dry clean only clothes indicated problems more frequently. In regards to manufacture's liability: women's clothes, woven clothes, wool clothes, silk clothes, wool blend clothes, polyester blend clothes, formal dress clothes, jackets, hanbok, and dry clean only clothes indicated problems more frequently. This study provides consumers with information necessary to take preventive measures and basic information that can be utilized to improve the quality of production and services by understanding the sources of dissatisfaction, type of clothes found with problems, and the main causes of consumer complaints for garment products according to who is liable.

• Proceedings of the KIEE Conference
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• 1996.07c
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• pp.1825-1827
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• 1996

In this study, the Joint of 345kV OF $1C{\times}2000mm^2$ cable was developed to keep up with the trends that need higher-voltage & capacity underground transmission line. The type of joint developed was based on the two kinds of models that have had a good reliability internationally. The mechnic and electric characteristics of the sample specimen was managed in detail when it was manufactured and estimated. Especially, in order to prove the reliability of usage for 30 years, the method of long term aging test was studied. As a result of test, we knew that the joint developed had a good performance. From this study, it can be thought that future ultra-high voltage underground transmission line could be constructed by domestic technology.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.8 no.1
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• pp.27-36
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• 2005

Geosynthetic reinforcements may be damaged during its installation in the filed. The installation damage mainly depends on two factors such as materials used and construction activities. This paper describes the results of a series of field tests, which are conducted to assess the installation damage of geogrid according to different maximum grain sizes of fills (40, 60, and 80 mm). These tests are done in three sites for twelve different kinds of geogrids. After field tests, the changes in tensile strength of the geogrids is determined from wide width tensile tests using both damaged and undamaged specimens. In the results of tests, tensile strength of the relatively flexible geogrids after field installation tests was decreased about from 20% to 40% according to the increment of the maximum grain size. On the other hand, for the relatively stiff geogrids, the loss of the tensile strength after site installation was examined below 5.2% independent of the maximum grain size of the soils. The results of this study show that the installation damage significantly depends on the stiffness of geogrid and is more obvious to a flexible geogrid and a fill material having higher maximum grain size.