• Journal of the Korean Geotechnical Society
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• v.33 no.9
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• pp.49-60
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• 2017

The purpose of this study is to investigate the behavior of a single batter pile with repeated lateral loading through model tests. Repeated loads were applied in one direction and two directions, and lateral resistance and bending moment were analyzed by varying the relative density of the ground. As a result, lateral resistance and maximum bending moment were increased in the order of Out batter, Plumb, and In batter when one-way and two-way dynamic lateral loads were applied. The depth at the maximum bending moment was more deeper with the loading. The moments at bottom layer were decreased in the order of Out batter, Plumb, and In batter but upper moments were increased with the same order. Also, various bottom and upper moments were small when the two-way dynamic lateral load was applied compared to one-way lateral load.

• Journal of the Korean GEO-environmental Society
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• v.6 no.1
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• pp.73-82
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• 2005

Generally, to evaluate a slope stability of the geosynthetic reinforced soil slope, the modified version of limit equilibrium method can be used. In most cases, resisting effects of reinforcement are dealt with considering an increased shear strength on the potential slip surface. However, it is not clear that the methods satisfy all three equilibrium equations. In this study, the new slope stability analysis method in which not only reinforcing effects of geosynthetics can be considered but also all three equilibrium equation can be satisfied is proposed. A number of illustrative examples, including published load test of large-scale reinforced retaining wall and centrifuge model tests on the geotextile reinforced soil slopes, are also analyzed. As a result, it is shown that the newly suggested method produces a relatively accurate factor of safety.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.31 no.3
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• pp.387-400
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• 2021

The increase in number of streaming platforms and contents thereof, owing to an advancement of cloud environment, has triggered the rapid proliferation of illegally replicated contents as well as legal contents. This necessitates the development of technology capable of discriminating the copyright infringement of various contents. The Korea Copyright Protection Agency operates a video content demonstration system using AI, but it has limitations on distortions such as resolution changes. In this paper, we propose the powerful mechanism using skeleton, which is resistant against distorted video contents and capable of discriminating copyright infringement of platforms streaming illegal video contents. The proposed mechanism exploits the calculation of Hamming distance to the original video by converting collected data into binary ones for the efficient calculation. As a result of the experiment, the proposed mechanism have demonstrated the discrimination of illegally replicated video contents with an accuracy of 94.79% and average magnitude of 215KB.

• Journal of the Korean Geotechnical Society
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• v.24 no.4
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• pp.23-36
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• 2008

This study describes model tests on instrumented rectangular-shaped passive row piles embedded in horizontal sand-ground undergoing lateral soil movement. We tried to find the property of row piles dependent on the shape of pile, including the position of the pile in row, pile spacing, and soil movement. The results of test are as follows. The lateral earth pressure diagram variously appeared to be triangle, trapezoid and rectangular by shape and position of pile. The outer pile has a larger bending moment than the inner pile in the case of B-type, the inner piles has larger one than outer pile in case of H-type. $R_f$ (the ratio of resistance to lateral soil movement) was found to increase with increasing pile spacing irrespective of pile-shape. Y/L (location of action of lateral resistance force) for $d_s$ (displacement of soil) and $S_h$ (spacing of pile) appeared to be nearly regular position, and H-type is higher than B-type.

• Journal of the Korean Geotechnical Society
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• v.25 no.10
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• pp.5-15
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• 2009

This paper presents the results of full-scale uplift load tests performed on 24 passive anchors grouted to various lengths at Okchun and Changnyong site. Rock anchors were installed over a wide range of rock types and qualities with a fixed anchored depth of 1~6 m. The majority of installations used D51 mm high grade steel rebar to induce rock failure prior to rod failure. However, a few installations included the use of D32 mm rebar at relatively deeper anchored depth so as to induce rod failure. In many tests, rock failure was reached and the ultimate loads were recorded along with observations of the shape and extent of the failure surface. In addition to field tests, laboratory pullout tests were conducted to determine bond strength and bond stress-shear slip relation at the tendon/grout interface when a corrosion protection sheath is installed in the cement-based grout. The test results show that the ultimate tendon-grout bond strength is measured from 18~25% of unconfined compressive strength of grout. One of the important results from these tests is that the measured strains along the corrosion protection sheath were so small that practically the reduction of bond strength by the presence of sheath would be negligible.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.30 no.4C
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• pp.175-183
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• 2010

The load distribution and deflection of large diameter piles are investigated by lateral load transfer method (p-y curve). The emphasis is on the effect of the soil continuity in a laterally loaded pile using 3D finite element analysis. A framework for determining a p-y curve is calculated based on the surrounding soil stress. The parametric studies that take into account the soil continuity are also presented in this paper. Through comparisons with results of field load tests, it is found that the prediction by the present approach is in good agreement with the general trend observed by in situ measurements and thus, represents a significant improvement in the prediction of a laterally loaded pile behavior. Therefore, a present study considering the soil continuity would be more economical pile design.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.13 no.3
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• pp.222-228
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• 2008

We conducted a dynamic analysis of an underwater test collector, which operates on extremely soft soil of deep-seafloor. The underwater test collector consists of nodule pick-up device, vehicle tracks, nodule crusher, loading frame and electric-electronic system. The weight of underwater test collector is about 8600 kg. The average normal pressure, that the underwater test collector supports, is about 6.0 kPa. The dynamic analysis model of underwater test collector is developed using commercial software RecurDyn-LM and Visual Fortran 90. A terramechanics model of extremely soft soil is implemented to the software based on user-written subroutine and applied to the dynamic analysis of the underwater test collector model. The dynamic responses of test collector are studied with respect to track velocities, terrain conditions, and coefficients of added mass and drag.

• Journal of the Korean Geotechnical Society
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• v.26 no.7
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• pp.117-133
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• 2010

A hybrid system of soil-nailing and compression anchor is proposed in this paper; the system is composed of an anchor bar (installed at the tip) with two PC strands and a steel bar. After drilling a hole, installing proposed hybrid systems, and filling the hole with grouting material, prestress is applied to the anchor bar to restrict the deformation at the head and/or to prevent shallow slope failures. However, since the elongation rate of PC strand is much larger than that of steel bar, yield at the steel bar will occur much earlier than at the PC strand. It means that the yield load of the hybrid system will be overestimated if we simply add yield loads of the two - anchor bar and PC strands. It might be needed to try to match the yielding time of the two materials by applying the prestress to the anchor bar. It means that the main purpose of applying prestress to the anchor bar should be two-fold: to restrict the deformation at the nail head; and more importantly, to maximize the design load of the hybrid system by utilizing load transfer mechanism that transfers the prestress applied at the tip to the head through anchor bar. In order to study the load transfer mechanism in a systematic way, in-situ pullout tests were performed with the following conditions: soil-nailing only; hybrid system with the variation of prestress stresses from 0 kN to 196 kN. It was found that the prestress applied to the anchor system will induce the compressive stress to the steel bar; it will result in decrease in the slope of load-displacement curve of the steel bar. Then, the elongation at which the steel bar will reach yield stress might become similar to that of PC strands. By taking advantage of prestress to match elongations at yield, the pullout design load of the hybrid system can be increased up to twice that of the soil-nailing system.

• Proceedings of the Technology Innovation Conference
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• 1996.12a
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• pp.325-340
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• 1996

산업성장 잠재력과 기술개발과의 관계는 기술개발을 통해 산업이 어떻게 성장될 수 있는가를 보여주는 관계를 말한다. 첫째는, 산업의 출현(Emergence)이다. 이는 기술개발에 의해 새로운 산업이 발달되는 경우를 말한다. Microcomputer의 출현이 그 대표적 예이다. 둘째, 산업의 재생(Revitalization) 이다. 하향곡선을 그리는 산업이 기술혁신을 통해 새로운 마켓을 개척하여 다시 활기를 띄게 되는 경우이다. 전자 장난감이 장난감 시장의 활성화를 가져온 경우가 이에 속한다. 셋째, 산업의 대체(Substitution)현상은 기술개발에 의해 기존의 산업이 새로운 산업으로 대체되는 경우를 말한다. 진공관 이 트랜지스터를 대체된 경우나 LP가 Compact Disc등으로 대체된 경우도 이에 속한다. 마지막으로, 산업의 퇴보(Decline)는 기술의 개발이 오히려 산업자체의 퇴보나 침체를 가져오는 경우를 말한다. 마모에 저항력이 강한 고무가 타이어산업의 침체를 간져온 경우가 이에 속한다. 본 논문은 과거 10여 년간의 한국의 각종 기업의 기술개발 사례를 통해 이러한 4가지 패턴의 산업성장잠재력에 그러한 기술개발이 어떠한 역할을 하여 왔는가를 규명하고, 한국기업의 기술개발 현황파악을 통한 당면한 문제점을 분석한다. 아울러 한국의 기업들이 한국적 경제 및 경영 환경하에서 어떠한 기술개발과 혁신을 통해 산업성장 잠재력에 기여할 수 있는가를 토론한다.

• Proceedings of the KSR Conference
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• 2011.05a
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• pp.423-426
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• 2011

The excessive axial load occurred in an immovable zone of continuous welded rail(CWR) tracks threatens the security of running trains due to the track buckling in extreme hot summer. The influence factors, such as rail temperature for compressive stress, ballast resistance for track stiffness and initial imperfection of track for tracks irregularity are uncertain track parameters that are randomly varied by climate conditions, operating conditions and maintenance of track etc. So, buckling of CWR tracks has very high uncertainties. Therefore, applying the probabilistic approach method is essential in order to rationally consider the uncertainty and randomness of the various parameters. In this study, buckling sensitivity analysis was carried out with respect to the characteristics of probability distribution of lateral ballast resistance using the buckling probability evaluation system of CWR tracks developed by our research team.