• Journal of the Korean GEO-environmental Society
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• v.16 no.12
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• pp.5-12
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• 2015

Since blasting noise is impact noise, it will give a sudden shock to the human. In the case, such as the blast vibration, it has given aging buildings and livestock great damage to move the vibration along ground in nearby regions. In this study, the influence of the blasting generated during excavation was analyzed for effects on regional. A couple of field and laboratory surveys about geological were carried out to figure out the geological ratio in the study-performed area. Blast vibration noise was compared to the domestic and abroad case studies and each of the institutions permissible standards established the most appropriate criteria in site condition. The vibration velocity of blasting vibration exploits the values which were measured from test blasting on the ground in order to examine blasting effect. Considering the blasting point as the shortest distance from safety facilities (farms, private houses, etc.), the examination of the influence range, which was derived from the vibration velocity of blasting vibration, was performed to figure out how the point affected the safety facilities. Three-dimensional numerical analysis was performed a time history analysis in order to analyze the behavior of the structure for a dynamic blast load, which was determined in three directions of the blast vibration value. The results of three-dimensional numerical analysis and the blasting effect of blasting vibration estimation equation blasting vibration of impact circle with accompanying test blasting were compared. And the analysis confirmed similar results figures.

• Journal of the Korean Geotechnical Society
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• v.18 no.1
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• pp.101-112
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• 2002

In this study, a new methodology fur the assessment of liquefaction potential is proposed and characteristics of the proposed methodology are verified. The experimental parameter of this methodology, that is, the plastic shear strain trajectory, is compared with the dissipated energy. It is shown that this parameter can express the liquefaction behavior which is generated by excess pore water pressure. This methodology takes advantage of the shear strain time history determined from the site response analysis based on the real time history of earthquake. In this site response analysis, shock type and vibration type records of similar predominant frequency are inputted. The liquefaction safely factors based on the proposed methodology and Korean detailed assessment related to the classical method are calculated from the results of the site response analysis and laboratory dynamic tests. Through this study, it is found that the proposed methodology can not only simulate the liquefaction behavior of saturated soils hut also express the seismic characteristics reasonably : leading type, predominant frequency, maximum acceleration, duration time.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2013.04a
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• pp.708-713
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• 2013

본 연구의 목적은 400km/h 급 고속철도 소음저감용 방음벽 상단장치를 개발하기 위함이다. 이를 위해 우선 현장에서의 소음측정을 통한 400km/h 급 고속철도(HEMU) 및 300km/h 급 KTX의 주파수특성을 분석하였다. 그리고, 해석적 기법(BEM) 및 시작품 제작을 통한 실내실험을 수행하여 3dB(A) 이상의 소음을 저감시킬 수 있는 상단장치를 설계하였다. 마지막으로, 상단장치 시작품을 제작하여 옥외시험실에서의 성능시험을 수행하였으며, 고속철도의 주파수특성을 반영한 상단장치 설치 전후의 감음량을 평가하였다.

• Computational Structural Engineering
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• v.9 no.4
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• pp.107-115
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• 1996

Displacement response is one of the important parameter to determine vibration characteristics of bridge structure. Reliable estimate of displacement response is obtained economically from integration of measured acceleration data in frequency domain. Proper sampling rate of frequency in discretization process of measured acceleration is proposed. Comparison of integrated and directly measured displacement response from laboratory experiment for a cantilever beam shows good agreement each other. Mode shape obtained from estimated displacement response also closely match with analytical result, thus the developed method is proved to be effective in practical use.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2003.05a
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• pp.313-316
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• 2003

This paper presents stand-alone electric power generator using bridge vibration for charging system of health monitoring sensor unit of bridge structure. In this paper, a novel electric power generator utilizing vertical vibration is proposed, which has minimum effect of armature reaction, and the related mechanical and electrical design equations are obtained and then a pilot electric power generator has been implemented. Moreover, the free oscillation test reveals that diode characteristics of rectifier is dominant factor in charging process. Also, simulation results with the Namhae bridge data showed the validity and effectiveness for stand-alone electric power generation.

• Journal of the Korean GEO-environmental Society
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• v.11 no.11
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• pp.47-54
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• 2010

Nowadays, geosynthetics for reinforcement and protection are widely applied to the waste landfill site. Current research indicates the potential for progressive failure in geosynthetic-soil system depends on the interface shear strength governed by several intrinsic factors such as moisture, normal stress, chemical, etc. In particular, the effect of the acidity and basicity from the leachate is intensively reviewed to assess the chemical reaction mechanism of interface shear strength under the cyclic loading condition. New multi-purpose interface apparatus(M-PIA) has been manufactured and the cyclic direct shear tests using submerged geosynthetics and soils under the different chemical conditions have been performed, consequently, the thickness of interface and shear stress degradation are verified. The basic schematic of the Disturbed State Concept(DSC) is employed to estimate the shear stress degradation in the interface, then, normalized disturbed function is obtained and analyzed to describe the shear stress degradation of geosynthetic-soil interface with chemical influence factors under dynamic condition.

• Journal of the Korean GEO-environmental Society
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• v.3 no.3
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• pp.65-77
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• 2002

Based from the results of various field and laboratory tests, it was determined that VCCP(Vibrated Crushed-stone Compaction Pile) Method is more effective compared to SCP(Sand Compaction Pile) Method. VCCP method effectively increases soil bearing capacity and reinforces soil and slopes, prevents liquefaction, enhances drainage. But when it comes to the engineering design these factors are not considered, instead designs are performed using practical methods and equations. Furthermore, this method is very economical since crushed stone can be used instead of sand and it can be also used in off-shore construction. In this paper, it will be synthetically considered technical state at the present time, research object after this and necessity of research for VCCP Method.

• Transactions of the Korean Society of Mechanical Engineers
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• v.15 no.3
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• pp.824-833
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• 1991

본 연구에서는 차체구조계의 진동모드 변수와 차실음향계의 음향모드변수들이 어떻게 관련되어 차실소음을 결정하는 가를 밝혔다. 그 결과, 수치해석 결과의 효용 성을 높이고 실내소음 평가방법을 체계화 시킬 수 있었으며, 효과적인 소음저감을 위 한 유용한 자료를 얻을 수가 있었다. 한편, 이제까지의 차실소음의 응답해석에서 가 장 큰 오차의 발생요인은 차체의 구조진동 모드데이타인데, 본 연구에서는 유한요소해 석 대신 모드시험 결과를 이용함으써, 유한요소 모델리이 어려운 경우의 소음 해석의 신뢰도를 높일수가 있었다.

• Magazine of the Korea Concrete Institute
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• v.10 no.4
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• pp.171-182
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• 1998

Vibration-controlled concrete has been developed by using various concrete mixtures, such as latex, rubber powders, plastic resins and polystyrene(styrofoam). As part of the recycling research of obsolete aged tires and plastic materials, various vibration-reducing mixtures are used for 10 concrete panels having above 200 kg/cm$^2$ in uniaxial compressive strength. Plywood box with sand uniformly saturated by the raining device has been used for the analysis of the impact wave, of which data have been transfered by the FFT technique to comparatively investigate damping ratios of 10 concrete panels.According to wave propagation analysis on vibration-controlled concrete for this research, it can be concluded that Latex concrete has relatively larger damping ratios than those for noncontrolled normal concrete in a similar compressive strength

• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.6D
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• pp.675-683
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• 2009

A Basic experimental study for the development of vibration-power generation system from the vibration energy of urban infrastructure, such as a railroad, highway, and bridges, was carried out to harvest electricity from moving vehicles. Starting with the proposal of vibration power generator which converts vibration energy to an electric power by using self-induction technology, the research explains the basic concept of self-induction technology and the dynamic characteristics of a ibration power generator. Also, in order to analyze the correlation of an electromotive force from vibration power generator which depends on external force and vibration speeds, many indoor experiments with various variables were achieved. Based on the experimental results, a vibration power generator system's ability were analyzed. With those results, basic data of vibration power generator system to acquire the maximum available power was confirmed.