• Journal of the Korean Geosynthetics Society
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• v.12 no.1
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• pp.39-50
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• 2013

This study aims at investigating the behavior of the ground water level when installing upward soil nails that drain water as well. To do this, a series of down-scaled model tests were conducted. A model slope with weathered soils was prepared and then an artificial rain was scattered on the slope. The relative densities of soil specimen were 60%, 75%, and 90%, and the rainfall intensities 50mm/hr, 75mm/hr, 100mm/hr, and 125mm/hr, respectively. The experimental parameters, such as the ground water level, ratio of soil runoff, and failure mode of the slope were measured and analyzed. As the results, It may be concluded that the ground water level in the slope supported by drainable upward soil nails increases very gradually while the unsupported soil changes dramatically. In addition, the ground water level becomes constant and no failure occurs as time goes by. In case of the relative density of 75%, the runoff ratio seemed to increase up to about 8~15% after reinforcement.

• Journal of the Korea Concrete Institute
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• v.17 no.6 s.90
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• pp.975-982
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• 2005

Scientific community agrees about the fact that base Isolation provides interesting solutions to minimize the seismic risk. Reliability of such a technique is nowadays proofed by a large number of applications like public buildings, nuclear plants, bridges, etc. This paper reports the results of performance verification tests of the base isolated RC building with the laminated rubber bearings which is manufactured by enterprise in Korea. The shaking table tests were performed using a three story model scaled to 1/3 of the prototype RC apartment building. Several major earthquake records were scaled to different peak ground accelerations and used as input base excitations. Especially in this study, effect of earthquake characteristics on response reduction and effect of the intensity of excitations are studied. Through the verification tests, the validity of the applied base isolaion device and the response reduction effect against earthquakes are confirmed.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.7
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• pp.4588-4594
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• 2014

In this study, small scaled (1/30) laboratory chamber tests of the pile foundation for a lightweight concrete pavement system were carried out to evaluate the safety of a pile foundation on sandy soil. The testing ground was simulated in the field and a standard pile-loading test was conducted. The test piles were divided into 3 types, Cases A, B and C, which is the location from the center of the slab by applying a vertical load. The interval between the piles was set to 8 cm. As a result of the pile foundation model test, the pavement settled when the vertical load was increased to 12kg from 1.5kg in sandy soil ground, particularly the maximum settlement of 0.04mm. Judging from the model chamber test, Case A showed compressive deformation, whereas Case B represented the compression and tensile forces with increasing vertical load. Case C showed an increase in tensile strain.

• Fire Science and Engineering
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• v.26 no.6
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• pp.85-91
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• 2012

To reduce human life and property damage at the fire in a building, it is most critical to control flame spread in the early stage. Fire spread prevention measure generally includes fire resistance performance securing of structure member in the arson zone and use limitation based on combustion performance of finishing material. The latter is most fundamental fire safety design to determine flame spread, but domestic combustion test determines combustion performance by specimen sized fire test method. Thus, there are many restrictions in the determination of combustion performance by composite material such as sandwich panel. Especially, outer finishing material uses a variety of composite material such as dry bit, aluminum composite panel, and metal panel compared to inner finishing material. Therefore, this study would determine vertical fire spread features by a full scaled fire experiment through the test method of ISO 13785-2, an international test standard.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2008.04a
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• pp.178-183
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• 2008

A robot crane truck is being developed by the Bridge Inspection Robot Development Interface(BRIDI) for an automated and/or teleoperated bridge inspection. At the end of the telescoping boom allows the operator to scan the bridge structure under the deck trough the camera. Boom vibration induced by wind and deck movement can cause serious problems in this scanning system. This paper presents a control system to mitigate such vibration of the robot boom In the proposed control system an actuator is installed at the end of the working boom. This control system is studied using a mathematical model analysis with LQ control algorithm and a scaled model test in the laboratory. The study indicates that the proposed system is efficient for the vibration control of the robot booms, thereby demonstrating its immediate applicability in the field.

• Proceedings of the Acoustical Society of Korea Conference
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• 1994.06c
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• pp.111-115
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• 1994

In this paper, a variable time-scale modification using SOLA is proposed, which takes into consideration the different time-scaled characteristics of voiced and unvoiced speech. The conventional method performs time-scale modifiction at a uniform rate for all speech. For this purpose, voiced and unvoiced speech duration at various taling speeds were statistically analyzed. A clipping autocorrelation functio was applied to each analysis frame to detemine voiced and unvoiced speech to obtain respective variation rates. The results were used to perform variable time-scale modification to evaluate performance, a MOS test was conducted to compare the proposed voiced/unvoiced variable time-scale modification and the uniform SOLA method. Results indicate that the proposed method produces sentence quality superior to that of the conventional method.

• Proceedings of the KIPE Conference
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• 2016.07a
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• pp.357-358
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• 2016

This paper presents a dynamic, electric-thermal model for a photovoltaic (PV) cell that combines electrical and thermal parameters. In this model, the irradiance and ambient temperature are used to calculate the PV cell temperature based on a five-layer thermal model. The cell temperature is then used in the electrical model to accurately adjust the PV cell output electrical characteristics and power. A custom experimental setup was built to test and verify the electrical and thermal characteristics of the PV cell and its surrounding layers. The electric-thermal model is validated using experimental data in realistic scenarios. This PV model can be scaled up and used to simulate PV systems in wide variety of applications, extreme environmental conditions, and fault conditions in real-time.

• Proceedings of the Korea Concrete Institute Conference
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• 1992.10a
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• pp.179-184
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• 1992

Four 3-story 1/2 scaled large concrete panel structures were designed and tested to estimate the seismic resistance capacity of large concrete panel high rise building systems, Test specimens were modeled three story of 24 or 15 story buildings and set up to represent the actural stress of the building . The axial force was constant and the horizontal force was loaded by ductility ratio. Results indicated that the joints of specimens were behavied monolithically to maximum strength. It was shown that the joint box connecting system had lower maximum strength and energy dissipation capacity than welding connection system, but had better deformation capacity.

• Proceedings of the Korea Concrete Institute Conference
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• 1993.04a
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• pp.136-141
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• 1993

8 Wall specimens (1/2 scaled) used welded wire fabric (Ф=6mm) and ordinary deformed reinforcement(D6) of which their ultimate tensile strength were almost same were tested to investigate the inplane-flexural behavior. Test results show that : 1. The wall strength with welded wire fabric was 20% less than that with deformed bar. 2. The wall ductility ratio of welded wire fabric was 1/3 times than that of deformed bar, approximately. 3. It is recommened that lap splice of welded sire fabric should be avoided in critical fracture zone.

• Proceedings of the Korea Concrete Institute Conference
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• 1999.10a
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• pp.565-568
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• 1999

The objective of this study is to investigate the hysteretic behaviors of exterior beam-column joints with high strength concrete (f'c≒1000kg/$\textrm{cm}^2$) subjected to cyclic loads. Four exterior subassemblages scaled down about 60% were tested, whose variables were with/without shear reinforcements and with/without slab and spandrel beams. Hoop bars and hooked steel fibers were used as the shear reinforcements. The test results showed that using hooked steel fiber reinforced concrete with volume ratio 1.5% at beam-column joints was very effective to resist shear stress due to cyclic loads.