• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.1
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• pp.379-384
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• 2006

Since the monolithic ceramic substrate was introduced for automotive catalytic converters, the durability of the substrate has been a continuing requirement to reduce the emission gas of vehicle. The substrate can occupy a volume as small as 82 $cm^3$ and as large as 8200 $cm^3$ to provide the required substrate for catalytic activity. The long-term durability varies with the size of the substrate from manufacture's point of view. Therefore This study presents that the response surface model using central composite design can explain size effect on the modulus of rupture in a cordierite ceramic monolithic substrate.

• Journal of the Korean Recycled Construction Resources Institute
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• v.8 no.2
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• pp.175-182
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• 2020

The application of epoxy coated reinforcements is increased as a means to prevent a corrosion of reinforcements embedded in reinforced concrete structures, However, epoxy coating may reduce the bond capacity between concrete and reinforcement, which results a longer development length and lap splice length. This paper aims to the possibility of modification in lap splice length from reduction of basic development length which was confirmed using a direct pull out test. Total 36 beam specimens were tested to compare the lap splice properties of normal and epoxy coated reinforcements with beam-end test for various lap lengths and diameters of reinforcements. According to the results on failure modes, deformations, and crack widths of this experiments, the modification factor of 1.2 should be used, though the direct bond capacity is assured through direct pull out test.

• Journal of Aerospace System Engineering
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• v.15 no.5
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• pp.43-49
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• 2021

This research shows how is designed, and its performance is evaluated on the ground for the VTOL drone before the flight test initiates. The targeted drone weight is approximately 45 kg including battery packs, and 4 motors are utilized to produce thrust and control directions. 30 min flight schedules were simulated to estimate the total power consumptions which result in 2.4 kWh. Then, two packs of 13-cells lithium-polymer battery with operating voltage ranging between 54 V and 44 V with up to 4 C-rate were fabricated to safely operate a VTOL drone. Moreover, the battery management system was installed to prevent over and under-voltage and over-current while running a battery system. To finally verify battery's performance, we conducted a ground evaluation for discharging battery tests at -10 ℃, 25 ℃ and 40 ℃, resulting in satisfying simulated power consumption conditions for flight schedules.

• Proceedings of the Korean Association of Geographic Inforamtion Studies Conference
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• 2004.03a
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• pp.579-585
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• 2004

지반정보DB는 NGIS 2단계 기본계획의 하나인 ‘지하지리정보’구축 시 프레임이 되는 정보로써 건설교통부는 '00년부터 전 국토를 대상으로 DB화하는 사업을 추진하고 있다. 그러나 이러한 정보가 지반의 개괄적인 상태파악에만 목적이 있을 뿐, 보유한 공학정보를 이용하여 지반해석과 상세설계에는 활용하지 못하고 있는 실정이다. 본 연구에서는 지반정보 DB에서 공간정보와 시추 및 공학시험정보를 실시간으로 불러들이고, 정의한 알고리즘에 따라 토공량 산정, 지지력 산정, 침하량산정, 연약지반 평가, 액상화 평가를 수행하는 GIS Client를 개발하였다. 사용자는 Client로 지도상에서 구간 및 각종정보를 입력할 수 있으며, 그 결과를 수치 혹은 평면도 형태로 제공받을 수 있다. 본 연구를 통해 지반정보 DB 수요를 건설계획 및 설계 등 실무 전반으로 넓힐 수 있으리라 기대된다.

• Annual Conference of KIPS
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• 2000.04a
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• pp.1017-1020
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• 2000

정보 시스템을 개발하고 관리하는 제반 활동들이 효율적으로 수행되고 있는지 점검하고 확인할 필요가 있다. 지금까지의 감리는 감리인의 정보 시스템 개발 및 감리경험에 의존하고 있으며, 평가방법에 있는 각 항목 기준이 애매하고, 정성적 평가로 인해 객관성이 결여되었다. 또한, 감리 정보 시스템이 개발되지 않아서 감리업무 평가에 활용되지 못하는 한계점이 있었다. 본 논문에서는 기존 감리업무의 제반 문제점을 해결하기 위하여 감리 정보 시스템의 모델을 제안하고, 시험 감리를 위한 감리 정보 시스템을 설계한다.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2005.11a
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• pp.47-55
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• 2005

A design of a dismantling mock-up system have been established based on the result that analyzed a characteristic of modules which need to design a virtual dismantling facility. A unit program composed of a various module such as a decommissioning database system. 3D dosimetric mapping that represents a distribution of a radionuclide contamination, a evaluation module for a dismantling schedule and cost A research of software architecture was carried out in order to Integrate these components that have been independently operated. The result was established an architecture that consis of a visualization module which could be visualized D&D activities and a simulation module which tan he evaluated a dismantling schedule and decommissioning cost.

• Journal of the Korean Geosynthetics Society
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• v.2 no.3
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• pp.3-9
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• 2003

Geosynthetics as a reinforcing material for earth structures have ever increased due to their excellent economy, fine external appearance, and easy construction. Geogrids are high-strength, orientated-polymer grid structures used to reinforce soil. This paper deals with the construction and sire monitoring for a 5.1m high-reinforcd slope with $75^{\circ}$ steep. The purpose of site monitoring is to evaluate the applicability of reforced slope with geogrid. Full scale field performance during and after construction was monitored by incorporating instrumentation including strain gauges on the geogrid, and horizontal and vertical movements.

• Journal of the Society of Disaster Information
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• v.16 no.4
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• pp.638-649
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• 2020

Purpose: The objective of this study is to evaluate the load carrying capacity of a target bridge structure based on the simple slab bridge of concrete over 20 years of public service. Method: By performing static loading test and dynamic loading test, the displacement, strain, impact factor, and natural frequency values were measured and evaluated through analysis method. Result: The main results of this study are as follows. First, the maximum displacement and maximum strain of S1 were assessed at 2.917 mm and 44.720 𝜇ε( tensile) and -13.760 𝜇ε(compression), respectively, with S2 maximum displacement and maximum strain being 2.100 mm and 4.870 𝜇ε(tensile), respectively. Second, the maximum measured impact factor was 0.191 in section S1 A-A, and the maximum measured impact factor was 0.155 in section S2 C-C. Third, the natural frequency was assessed at 6.086 Hz, and the measurement was found to be within the range of 6.152 Hz to 6.738 Hz. Conclusion: The tested bridge may be evaluated to show good behavior and characteristics for the design load.

• Journal of the Korean Geosynthetics Society
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• v.22 no.4
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• pp.1-8
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• 2023

Space exploration is at the forefront of human scientific endeavors, and planetary exploration rovers play a critical role in studying planetary surfaces. Rover performance is especially vital for safely navigating steep terrain and delicate landscapes found on planets like Mars and the Moon. This paper offers a comprehensive overview of a landing testbed designed to simulate challenging extraterrestrial terrain and loose regolith. The paper briefly outlines lunar crater region topographical features and highlights the importance of these simulations in rover testing. It then explores previous landing testbed developments and describes the design process for a landing testbed to be installed in the dirty thermal vacuum chamber at the Korea Institute of Civil Engineering and Building Technology. Once realized, this proposed landing testbed will enable precise evaluations of rover mobility and exploration capabilities under lunar-like conditions, including high vacuum and extreme temperatures.

• Journal of the Earthquake Engineering Society of Korea
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• v.3 no.2
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• pp.41-54
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• 1999

Because of relatively heavy dead weight of concrete itself and unavoidable heat of massive concrete in bridge piers, circular hollow columns are widely used in Korean highway bridges. Since the occurrence of 1995 Kobe earthquake, there have been much concerns about seismic design for various infrastructures, inclusive of bridge structures. It is, however, understood that there are not much research works for nonlinear behavior of circular hollow columns subjected to eqrthquake motions. The objective of this experimental research is to investigate nonlinear behavior of circular hollow reinforced concrete bridge piers under the quasi-static cyclic load, and then to enhance their ductility by strengthening the plastic hinge region with glassfiber sheets. Particularly for this test, constant 10 cyclic loads have been repeatedly actuated to investigate the magnitude of strength degradation for the displacement ductility factor. Important test parameters are seismic design, confinement steel ratio, axial force and load pattern. It is observed from quasi-static tests for 7 bridge piers that the seismically designed columns and the retrofitted columns show better performance than the nonseismically designed colums, i.e. about 20% higher for energy dissipation capacity and about 70% higher for curvatures.