• Proceedings of the KIEE Conference
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• 1991.07a
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• pp.286-291
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• 1991

Most of the failures of rotating machine are stator coil insulation failures. The insulation diagnostic testing for high voltage motors and generators are only megger test and P. I Test which is applied DC voltage until now. But it was impossible to judge insulation deterioration status of high voltage rotating machinery by above testing. In other words, even though the megger measurement values are fairly high, they used to be failed from time to time. Therefore in order to excute reliable and detailed diagnosis of insulation deterioration for rotating machinery, the tangent delta test, the alternating current test and the partial discharge test shall be applied to the insulation diagnostic testing on site.

• Proceedings of the Korean Geotechical Society Conference
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• 2008.10a
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• pp.1204-1211
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• 2008

Compression index is one of the important characteristic numbers in soft soil engineering. Since 1940's, many researchers have suggested various practical solutions to define the compression index of clay using other soil properties. But, these results are only can give us an outline of soft soil behavior. In this study, the relationships between pore water pressure dissipation test results and compression index were suggested using comparison results of both tests. This relationships are based on basic concept of consolidation phenomena, essential difference between pore water pressure dissipation test and consolidation test, and disagreements between theoretical time factor and real time factor. To identify proportional factor of proposed equation, Geotechnical investigation results of Kwang-Yang(KY) site and Busan New Port(BN) site were used. The proportional factor was 0.0031 from 20 to 50% of consolidation rate where correlation parameter($R^2$) is 0.9051.

• Journal of the Korean Society of Clothing and Textiles
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• v.32 no.9
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• pp.1387-1396
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• 2008

The objective of this study was to identify differences between internet fashion shoppers and non-shoppers in their fashion shopping orientation and attitude toward internet shopping site service. Also behavior of internet shoppers and non-shoppers was compared by gender. Twelve hundred and ninety two responses were obtained from an online survey. 20 items were used to measure shopping orientation and 13 items to measure attitude toward internet shopping site service, which were modified from previous studies. Some demographics and internet familiarity were asked. Factor analysis, t-test, chi-square test, and regression were conducted. Factor analysis produced five fashion shopping orientation factors such as fashion oriented, shopping oriented, brand oriented, personality oriented, and value oriented. Attitude toward internet shopping site service were classified into three factors, at-site service, after purchasing service, and product information. Internet fashion shoppers and non-shoppers were significantly different in most items of shopping orientation and attitude toward internet site service. Internet shoppers were likely to be fashion oriented, to enjoy shopping, to pursue brandname and personality, and to concern price more than non-shoppers were. Internet shoppers also had more favorable attitude toward product information and at-site service. Also, shoppers were more familiar than non-shoppers to the internet in terms of duration of web-browsing. Ratio of men and women differed significantly for shopper vs. non-shopper groups. Female shoppers were likely to be more fashion, shopping. and value oriented but to have less favorable attitude for after purchasing service than male shoppers.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 1997.04a
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• pp.257-264
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• 1997

Seismic responses of the Hualien large scale seismic test model on a layered soil site are estimated for two recorded earthquakes and the analysis results are then compared and evaluated with the recorded responses. The method adopted for the analysis is based on substructuring method using a lumped parameter model in both the frequency and time domain. the study results indicate that the proposed method can reasonably estimate the earthquake responses of a soil-structure interaction system for engineering purposes.

• Tunnel and Underground Space
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• v.33 no.6
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• pp.472-482
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• 2023

The grid-type or room-and-pillar method is applied for the purpose of mining horizontally buried minerals. In this study, design and pilot test were performed to apply the room-and-pillar method which uses natural rock as a rock pillar to the construction of underground space. The area where the pilot test was conducted was in stone mine and had good rock conditions with an appropriate depth (about 30 m) to apply the pilot test. The pilot test site was selected by reviewing accessibility and ground conditions and then site construction was performed through detailed ground investigation and design. The pilot test was designed with a column shape of 8×8 m and a cross-section of 8×12 m. The blasting pattern was determined through test blasting at the site, and blasting of 3 m excavation with 89 holes was performed. Through field observations, the average width of 12.5 m and the average height of 8.3 m were measured. Therefore, it is possible to proceed similar to the cross-sectional shape considered in the design.

• Proceedings of the KIEE Conference
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• 2006.04a
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• pp.75-77
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• 2006

In this paper, the technology of the conformance test for Broadcast Web Site Service (BWS) which is one of the data services of the T-DMB (Terrestrial Digital Multimedia Broadcasting) is proposed. First, the standard of the BWS Service is introduced and then the method of the conformance test of BWS bitstream and BWS receiver module is provided. A BWS bitstream analyzer is implemented for use in verifying the transmitted BWS bitstreams. To provide a means for the receiver manufactures to verify their own BWS receiver modules, a receiver test suite is developed including BWS test bitstreams and a BWS reference receiver module. The BWS bitstream analyzer includes the analysis function for the conformance test of MOT protocol, HTML, PNG, MNG, JPEG, and Ecma Script. Also, it was actually used for verifying the BWS test bitstreams. In the course of developing a HWS receiver module, 4he BWS receiver module under test can be verified by comparing the results of the BWS reference receiver module with those of the receiver module under test. when the same BWS test bitstreams are fed into the two receiver modules.

• Earthquakes and Structures
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• v.15 no.1
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• pp.1-8
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• 2018

A new site classification system and site coefficients based on local site conditions in Korea were developed and implemented as a part of minimum design load requirements for general seismic design. The new site classification system adopted bedrock depth and average shear wave velocity of soil above the bedrock as parameters for site classification. These code provisions were passed through a public hearing process before it was enacted. The public hearing process recommended to modify the naming of site classes and adjust the amplification factors so that the level of short-period amplification is suitable for economical seismic design. In this paper, the new code provisions were assessed using dynamic centrifuge tests and by comparing the design response spectra (DRS) with records from 2016 Gyeongju earthquake, the largest earthquake in history of instrumental seismic observation in Korea. The dynamic centrifuge tests were performed to simulate the representative Korean site conditions, such as shallow depth to bedrock and short-period amplification characteristics, and the results corroborated with the new DRS. The Gyeongju earthquake records also showed good agreement with the DRS. In summary, the new code provisions are reliable for representing the site amplification characteristic of shallow bedrock condition in Korea.

• Nuclear Engineering and Technology
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• v.53 no.10
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• pp.3247-3255
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• 2021

As Probabilistic Safety Assessments (PSAs) are thoroughly conducted for the Site Operating States (SOSs) for a single unit, multi-unit Probabilistic Safety Assessments (MUPSAs) are ongoing worldwide to address new technical challenges or issues. In South Korea, the determination of the site operating states for a single site requires a logical approach with reasonable assumptions due to the fact that there are 4-8 operating units for each site. This paper suggests a simulation model that gives a reasonable expectation of the site operation states using the Monte-Carlo method as a stochastic approach and deterministic aspects such as operational policies. Statistical hypothesis tests were conducted so that the reliance of the simulation results can be guaranteed. In this study, 7 units of the Kori site were analysed as a case study. The result shows that the fraction of full power for all 7 units is nearly 0.45. For situations when more than two units are not in operation, the highest fraction combination was obtained for Plant Operation State (POS) 8, which is the stage of inspection and repairment. By entering various site operation scenarios, the simulation model can be used for the analysis of other site operation states.

• Journal of the Korea Concrete Institute
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• v.27 no.4
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• pp.419-426
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• 2015

The purpose of this study is to investigate experimentally the optimum mix design and site application case of soil mixing wall (SMW) method which is cost-effective technique for construction of walls for cutoff wall and excavation support as well as for ground improvement before constructing LNG storage tank typed under-ground. Considering native soil condition in site, main materials are selected ordinary portland cement, bentonite as a binder slurry and also it is applied $1,833kg/m^3$ as an unit volume weight of native soil, Variations for soil mixing wall are as followings ; (1) water-cement ratio 4cases (2) mixing velocity (rpm) 3levels (3) bleeding capacity and ratio, compressive strength in laboratory and site application test. As test results, bleeding capacity and ratio are decreased in case of decreasing water-cement ratio and increasing mixing velocity. Required compressive strength (1.5 MPa) considering safety factors in site is satisfied with the range of water-cement ratio 150% below, and test results of core strength are higher than those of specimen strength in the range of 8~23% by actual application of element members including outside and inside in site construction work. Therefore, optimum mix design of soil mixing wall is proposed in the range of unit cement $280kg/m^3$, unit bentonite $10kg/m^3$, water-cement ratio 150% and mixing velocity 90rpm and test results of site application case are satisfied with the required properties.

• Korean Journal of Agricultural and Forest Meteorology
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• v.14 no.2
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• pp.89-97
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• 2012

This study was conducted to estimate forest site productivity and productive areas of Quercus acutissima and Quercus mongolica using environmental factors including climatic variables. Using the data set from digital forest site map and forest climatic map, a total of 42 environmental variables were regressed on site index for developing the best site index equations for Quercus acutissima and Quercus mongolica. Five to six environmental factors by species were selected as independent variables in the best site index equations. For the site index equations, three evaluation statistics (i.e., mean difference, standard deviation of difference, and standard error of difference) were applied to the test data set for the validation of the results, The site index equations fitted well to the test data set with relatively low bias and variation. As a result, it was concluded that the site index equations by species were well capable of estimating site quality. Finally, based on the site index equations, the productive areas by species were estimated by applying GIS technique to the digital forest maps. In addition, the distribution of productive areas by species was illustrated.