• The Transactions of the Korean Institute of Electrical Engineers C
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• v.53 no.8
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• pp.420-424
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• 2004

This paper presents experimental data from model windings with different arrangement of coil in order to provide information to design a 22.9kV class HTS transformer. Before experiment, the composite insulation of two different type of HTS transformers are investigated. The first basic of investigation is a breakdown characteristic of liquid nitrogen and flashover characteristic on the GFRP surface under ac and impulse, The second investigation is insulation design, manufacture and test of model windings. These include a AC withstand voltage test of 50 kV rms and a lighting impulse test of 150 kV at peak.

• International Journal of Highway Engineering
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• v.17 no.6
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• pp.47-54
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• 2015

PURPOSES : The objective of this study is to evaluate the early adhesive characteristic of asphalt emulsions, including polymer-modified emulsions, for chip seals using the surface energy concept, the bitumen bond strength (BBS) test, and the Vialit test. METHODS : Two general methods, the BBS test and Vialit test, were applied to investigate the bond strength and the aggregate loss, respectively. A new theory, the surface free energy (SFE) theory, was used to evaluate the adhesive characteristic between the emulsion and the aggregate. Based on the theory, the contact angles were measured, and then the surface energy components were calculated. Using those components, the work of adhesion (Wa) was calculated for each emulsion. To ensure reliable results, all the tests were performed under the same conditions, i.e., at $25^{\circ}C$ for 240 minutes of curing time. For the materials, three emulsions (CRS-2, CRS-2L, and CRS-2P) and one aggregate type (granite) were employed. RESULTS AND CONCLUSIONS : Under the same conditions, the modified emulsions showed better adhesive characteristics and curing behaviors than the unmodified emulsions. In addition, there was no significant difference between the various modified emulsions. One of the important findings is that the analysis by Wa presents more sensitive results than other methods. The results of the Wa showed that the CRS-2P emulsion has the best adhesive characteristics. Consequently, the use of modified emulsions for chip seals could prevent aggregate loss and allow open traffic earlier.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.11a
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• pp.405-408
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• 2008

This study, as mock-up test for applying Polylon Fiber engineering method to the field, analyzed the fundamental characteristics and the fireproof characteristics of high strength concrete mixed with Polylon Fiber 0.05% and the results are summarized as followings. From the characteristic of the fresh concrete, both slump flow and air content were appeared to satisfy target range. And from the characteristic of hardened concrete, all compressive strengths according to the curing conditions were appeared to satisfy design standard strength of 60 MPa. From the fireproof characteristic, small scaling and spalling phenomenon were partially appeared on the surface part of specimens, but generally the excellent fireproof capacities were appeared. From the characteristic of temperature hysteresis, the highest temperature and the average temperature of reinforcing part after fire-resistant test for 3 hours were $531^{\circ}C$ and $405{\circ}C$, respectively and then satisfied fireproof standard of the Ministry of Land Transportation and Maritime Affairs.

• Journal of Korean Association for Spatial Structures
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• v.9 no.2
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• pp.77-82
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• 2009

ETFE is the abbreviation of Ethlene Tetra Fluoro Ethlene, a sort of colorless and transparent granules. The advantage of ETFE film has chemical resistance, anti-stick property, very lightly material. The thickness of ETFE film is used to from 50 ${\mu}m$ to 300 ${\mu}m$ and have superior ability of daylight transmission and elongation, while the strength is lower than of fabric membrane. The tensile strength of ETFE film changes from 40Mpa to 60Mpa and the tensile strain at break can get to about 300-400%. The mechanical characteristic test of ETFE film is described in this paper. The tensile strain at break, the tensile strength and the stress-strain curve are obtained from the test. And then it was analyzed stress-strain characteristic by temperature and mechanical characteristic by cycling load.

• Journal of KIISE:Software and Applications
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• v.33 no.10
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• pp.836-850
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• 2006

Nowadays, due to the rapidly increasing number of package software products, quality test has been emphasized for package software products. When testing software products, one of the most important factors is to select metrics which form the bases for tests. In this paper, the types of package software are represented as characteristic vectors having probabilistic relationships with metrics. The characteristic vectors could be regarded as indicators of software type. To assign the metrics for each software type, the past test metrics are collected and analyzed. Using Bayesian belief network, the dependency relationship network of the characteristic vectors and metrics is constructed. The dependency relationship network is then used to find the proper metrics for the test of new package software products.

• Wind and Structures
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• v.22 no.5
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• pp.555-571
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• 2016

A hanging-type sand-retaining wall is a very common sand-blocking fence structure used to prevent sand movement. This type of wall is widely used along the Qinghai-Tibet and Gobi desert railways in Xinjiang, Western China. To analyze the characteristics of wind-sand flow fields under the effect of such a sand fence structure, a wind tunnel test and a field test were carried out. The wind tunnel test showed the zoning characteristics of the flow fields under the effect of the hanging-type sand-retaining wall, and the field test provided the sediment transport data for effective wind-proof interval and the sand resistance data in the front and behind the sand-retaining wall. The consistency of the wind-sand flow fields with the spatial distribution characteristic of wind-carried sand motion was verified by the correspondences of the acceleration zone in the flow field and the negative elevation points of the percentage variations of the sand collection rate. The spatial distribution characteristic of the field sand collection data further showed the spatial structural characteristic of the sandy air currents under the action of the hanging-type sand-retaining wall and the sand resistance characteristic of the sand-retaining wall. This systematic study on the wind-sand flow fields under the control of the hanging-type sand-retaining wall provides a theoretical basis for the rational layout of sand control engineering systems and the efficient utilization of a hanging-type sand-retaining wall.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.54 no.4
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• pp.243-250
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• 2005

Test methodology is diversity by devices and the number of test pattern is tremendous because the digital circuit includes TTL and CMOS family ICs as well as high density devices such as ROM and RAM. Accordingly, the quick and effective test strategy is required to enhance the test productivity. This paper proposes the test strategy which is able to be applied efficiently to the diversity devices on the digital circuit board by analyzing the structure and characteristic of the digital device. Especially, this test strategy detects the faulted digital device or the faulted digital circuit on the digital board using SSA(Serial Signature Analysis) technique based on the polynomial division theory The SSA technique identifies the faults by comparing the reminder from good device with reminder from the tested device. At this time, the reminder is obtained by enforcing the data stream obtained from output pins of the tested device on the LFSR(Linear Feedback Shift Register) representing the characteristic equation. Also, the method to obtain the optimal signature analysis circuit is explained by furnishing the short bit input streams to the long bit input streams to the LFSR having 8, 12, 16, 20bit input/output pins and by analyzing the occurring probability of error which is impossible to detect. Finally, the effectiveness of the proposed test strategy is verified by simulating the stuck at 1 errors or stuck at 0 errors for several devices on typical 8051 digital board.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2001.05a
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• pp.159-162
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• 2001

A combined finite element and experimental study based on the characteristic length method is performed to investigate the strength and behavior of the pin joint in composite control rod. The failure is estimated by the Yamada-Sun and Tsai-Wu criteria on the characteristic curve. The gap elements are used to simulate the contact between the pin and the composite fitting with hole. The accuracy and applicability of the method are validated by the joint tests. All the specimens were failed in the bearing mode in the test and finite element analysis, and good agreement was found between the predicted and test results on the joint strength of composite control rod.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.9 no.1
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• pp.59-63
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• 2008

This paper analyze the operating characteristic of RCB due to the synthesize harmonic current. The RCB of rated sensitivity electric current with 30[mA] test to operating characteristic by synthesize harmonic current and it analyzed the tripping operation due to a harmonic current. The test result, the operating current of RCB changed by synthesize harmonic current.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2009.05a
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• pp.57-60
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• 2009

Exothermic and ignition characteristic of igniter is very important factor in engine performance. Since the igniter performance is effected by Hydrogen Peroxide decomposition rate, we have to test the preliminary catalyst performance test. In this report, after making igniter using hydrogen peroxide/kerosene, a thermal characteristic were examined by comparing hydrogen peroxide mass and catalyst mass. And then we study ignition characteristic of the affects of O/F ratio using the previous data.