• Journal of the Earthquake Engineering Society of Korea
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• v.27 no.1
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• pp.37-47
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• 2023

A new clamped mechanical splice system was proposed to develop structural performance and constructability for precast concrete connections. The proposed mechanical splice resists external loading immediately after the engagement. The mechanical splices applicable for both large-scale rebars for plants and small-scale rebars for buildings were developed with the same design concept. Quasi-static lateral cyclic loading tests were conducted with reinforced and precast concrete members to verify the seismic performance. Also, shaking table tests with three types of seismic wave excitation, 1) random wave with white noise, 2) the 2016 Gyeongju earthquake, and 3) the 1999 Chi-Chi earthquake, were conducted to confirm the dynamic performance. All tests were performed with real-scale concrete specimens. Sensors measured the lateral load, acceleration, displacement, crack pattern, and secant system stiffness, and energy dissipation was determined by lateral load-displacement relation. As a result, the precast specimen provided the emulative performance with RC. In the shaking table tests, PC frames' maximum acceleration and displacement response were amplified 1.57 - 2.85 and 2.20 - 2.92 times compared to the ground motions. The precast specimens utilizing clamped mechanical splice showed ductile behavior with energy dissipation capacity against strong motion earthquakes.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2003.03a
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• pp.148-156
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• 2003

Shaking table tests and pseudo-static analysis were performed, in this study, on newly-designed aseismatic L-type caisson quay walls, which were constructed by extending the bottom plate of gravity quay walls into the backfill soil. The L-type quay walls are expected to give economical benefits by reducing the cross-sectional area of the wall while maintaining its aseismatic efficiency as much as the classical caisson gravity quay wall. To confirm the effectiveness of the L-type structure, the geometry of L-type quay walls were varied for shaking table tests. And, to verify the influence of backfill soils on the seismic behavior of quay walls, additional shaking table tests were performed on the L-type quay wall after the backfill soils were replaced by gravels and light materials. As a result, it was found that L-type caisson quay walls are good earthquake resistant structures but increasing the length of bottom plate did not proportionally increase the effectiveness of the structure in its aseismatic performance. Replacing the backfill soils by the gravels and light materials, contrary to our expectation, was not an effective measure in improving the seismic performance of L-type caisson quay wall.

• 한국신재생에너지학회:학술대회논문집
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• 2005.11a
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• pp.599-603
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• 2005

To evaluate the performance of concentrating solar cookers, a parabolic solar cooker have been designed and constructed. Tests were carried out to define the performance characteristics of concentrating cookers under ambient conditions. The performance and test of the solar cooker were measured and conducted using the international standard procedure that was proposed at the Third World Conference on solar cooking. Stagnation temperature and water heating tests were carried out to determine the maximum temperature attained by the cooker and to evaluate the thermal performance of the cooker. The analysis showed that the solar cooker has maximum cooking power and efficiency 474W, 420W and 41%, 40%, respectively.

• Nuclear Engineering and Technology
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• v.55 no.3
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• pp.1181-1190
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• 2023

Hydraulic performance and flow resistance tests were performed to confirm the main parameters of the hydraulic instrumentation that can affect the pump performance of the reactor coolant pump. The flow resistance test offers important experimental data, which are necessary to predict the behavior of the primary coolant when the circulation of the reactor coolant pump is stopped. Moreover, the shape of the hydraulic section of the pump, which was considered in the test, was prepared to compare the mixed-flow- and axial-flow-type models, the difference in the number of blades of the impeller and diffuser, the difference in the shape of the impeller blade and its thickness, and the effect of coating at the suction bell. Additionally, five models of the hydraulic part were manufactured for the experiments. In this study, the differences in performance owing to the design factors were confirmed through the experimental results.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2005.10a
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• pp.53-66
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• 2005

[ $\cdot$ ] Performance can be evaluated beyond specification and requirements using existing pump tests $\cdot$ Bench testing of stressed fluids can deonstrate Retention of Performance

• Journal of the Earthquake Engineering Society of Korea
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• v.10 no.5 s.51
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• pp.107-115
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• 2006

The power supply system is one of the most important infrafacilities which should maintain their inherent function during and after earthquakes. This study was performed to analyze dynamic characteristics and seismic performance of Korean typical 154kV transformer porcelain bushing. For the purpose of this study, actual 154kV porcelain bushings were selected and tested on the shaking table. The vibration tests consist of modal identification tests, seismic performance tests, and fragility tests. The sine sweep waves, artificial earthquake waves, and continuous resonant sine waves were used as shaking table motions. This paper describes the test specimens, shaking facilities, and test methods. Natural frequencies and damping ratios of the bushing have been evaluated from the experimental data. The failure mode and the performance level of the Korean transformer bushing have been first identified in this study.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.9
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• pp.492-498
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• 2017

This study examined the bending performance of high strength and seismic purpose reinforcing bars experimentally with various parameters. For the experimental approach on the bending performance, the specimens were prepared with parameters, such as steel grades, diameters of reinforcing bars, and bending angles of reinforcing bars. Tensile strength tests on the reinforcing bars, the bending tests and re-bending tests, and the second tensile strength tests on the re-bended reinforcing bars were conducted. According to the test results on high strength and seismic purpose reinforcing bars, defects did not appear when the yield strength of the reinforcing bar was 500 MPa or less and the diameter was D13 or less, even when the first bending process was performed with a $135^{\circ}$ bending angle and a $2d_b$ inner radius. The bending performance decreased asthe strength and diameter of the reinforcing bars was increased. In addition, there was no significant difference between the general reinforcing bars and seismic purpose-reinforcing bars.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.41 no.11
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• pp.1472-1480
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• 2016

When disasters such as earthquake, flood, typhoon, fire and terrorism are occurred a video management system is required which can shoot video on the disaster site, and send it to a server located in the command center that can grasp at a glance the site conditions. In this paper, to know the performance elements information needed to construct the video management system. we presented a method of configuring an ad hoc network based on Wi-Fi direct communication. And we also evaluated the performance through built of environment for the video management system. The evaluated performance test items are 'packet flow tests according to the video compression ratios and the image sizes', 'packet flow tests according to the distance and traffic tests', 'packet flow tests according to whether LOS or not', and 'performance test of scenarios'.

• Korean Journal of Agricultural Science
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• v.44 no.4
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• pp.595-603
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• 2017

Crop growth and production cost are greatly influenced by management of environmental factors such as ambient temperature, humidity, and $CO_2$, especially in protected horticulture. Opening and closing of greenhouses is the most important operation for control of these ambient environmental factors, and precise and stable operation requires high performance window motors. In this study, a 400 W precise window motor was constructed, and its performance was evaluated for plastic and glass greenhouses. First, the motor was designed and fabricated by benchmarking of an advanced foreign product. Then, the performance was evaluated through vibration, PCB (Process Control Block), and load tests. Vibration tests resulted in averaged vibration displacement and velocity of the developed motor of 0.002 mm and 0.2267m/s, which were statistically significantly different from those of the target motor. Average vibration acceleration ($0.26m/s^2$) of the developed motor was also significantly different from that ($0.51m/s^2$) of the target motor. PCB tests showed 2 - 4 mm deviation from the target values, and confirmed the operating status and precision of the control. Load tests with a 300 kg load also showed acceptable operating status and durability. Current values were $1.31{\pm}0.06A$ and RPMs were in the range of 2.9 - 3.0. Considering the above results, the developed window motor would be competitive to the target foreign product.

• International Journal of Highway Engineering
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• v.15 no.2
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• pp.65-71
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• 2013

PURPOSES : The objective of this study is to evaluate the effect of physical characteristics of emulsion asphalt and aggregate on performance of chip seal pavements. METHODS : In order to evaluate the performance of chip seal materials, the sweep tests and Vialit Plate Shock tests were conducted on the mixtures with five emulsion asphalt binders and three aggregate types. The sweep tests was intended to investigate the change of bonding properties between emulsion asphalt and aggregate with curing time. The Vialit Plate Shock test was used to evaluate the bonding properties of chip seal materials at low temperatures. RESULTS : Results from sweep tests showed that polymer modified emulsion asphalt can reduce the curing time by 1.5 hour comparing with typical emulsion asphalt. It is also found that the Flakiness Index of aggregates and absorption rate of binder are the major factors affecting the bonding properties of chip seal materials. The Vialit Plate Shock test results showed that the average aggregate loss of CRS-2 is ten times higher than CRS-2P No.2 indicating that the use of polymer additives in emulsion asphalt can improve the performance of chip seal materials in low temperature region. CONCLUSIONS : The use of polymer in emulsion asphalt can decrease the curing time of chip seal materials and increase the bonding properties between aggregates and asphalt binder. It is also concluded that the lower Flakiness Index and absorption rate of aggregates can improve the performance of chip seal pavement.