• 한국산림과학회지
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• 제109권4호
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• pp.382-389
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• 2020

노천 광산 채굴지의 토양 물리·화학적 성질은 광산지 식생 복원의 가장 중요한 요인이다. 본 연구는 경상남도 산청군 고령토 광산의 고령토 폐석지와 식생 복원지 및 인접한 소나무 임분의 토양 성질을 비교하기 위하여 수행하였다. 고령토 채굴이 진행되고 있는 6개 지역을 선정하고 고령토 폐석지, 식생 복원지, 소나무 임분의 토양 10 cm 깊이에 물리·화학적 성질을 조사하였다. 토양 용적밀도는 고령토 폐석지가 1.51 g·cm-3로 식생 복원지 1.19 g·cm-3나 소나무 임분 0.93 g·cm-3에 비해 유의적으로(P < 0.05) 높게 나타났으며, 기상은 고령토 폐석지가 14.2%로 소나무 임분 32.6%에 비해 유의적으로 낮았다. 점토함량은 소나무 임분이 33.6%로서 고령토 폐석지 14.8%나 식생 복원지 18.7%에 비해 유의적으로 높았다. 토양구조 안정지수는 고령토 폐석지가 0.87%, 식생 복원지가 1.61%로 소나무 임분 7.75%에 비해 유의적으로 낮았다. 토양 pH는 고령토 폐석지 pH 6.68, 식생 복원지 pH 6.27로 소나무 임분 pH 5.31에 비해 유의적으로 높았다. 그러나 토양 유기탄소 농도는 고령토 폐석지 2.12 mg·g-1, 식생 복원지 5.00 mg·g-1, 소나무 임분 36.03 mg·g-1, 전질소 농도는 고령토 폐석지 0.07 mg·g-1, 식생 복원지 0.31 mg·g-1, 소나무 임분 2.08 mg·g-1로 고령토 폐석지와 식생 복원지는 소나무 임분에 비해 유의적으로 낮은 값을 보였다. 토양 내 유효 인 농도는 고령토 폐석지, 식생 복원지, 소나무 임분 사이에 유의적인 차이가 없었다. 토양 포타슘 농도는 고령토 폐석지 0.08 cmolc·kg-1과 식생 복원지 0.21 cmolc·kg-1로 소나무 임분 0.30 cmolc·kg-1에 비해 유의적으로 낮았다. 본 연구 결과에 따르면 고령토 노천 채굴지의 고령토 폐석지나 식생 복원지는 토양 용적밀도가 높고, 토양 유기탄소, 전질소, 유효 인, 교환성 포타슘 농도가 낮았으며 식생 복원지의 경우 토양 비옥도로 향상할 수 있는 관리 방안이 필요한 것으로 나타났다.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2003년도 봄 학술발표회 논문집
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• pp.605-612
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• 2003

In this study, the performance of the cut-off wall with the specific functional adsorption layers(containing SAC), which are formed in order to block harmful materials such as heavy metal ions contained in leachate (or outflow water) from either waste landfills or exhausted mines, was Investigated by determining experimental data such as hydraulic conductivities, unconfined compression strengths, adsorption capacities. The performance was compare to those of the present cut-off wall materials such as clay, bentonite-mixed soil, and soil-cement.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 2002년도 proceedings of the second asia international conference on tribology
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• pp.73-75
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• 2002

Recently, remarkable agreement has been reported between nonequilibrium molecular dynamics simulation and high-pressure Couette rheometry on squalane. We utilized the parameters obtained from this unique collaboration along with high-pressure viscometer measurements to calculate the elastohydrodynamic traction curve. A comparison with measured traction at 1.29 GPa shows excellent agreement, confirming the validity of the measurements and simulations. It should no longer be necessary to invoke a different rheological response to explain film thickness and traction.

• 한국군사과학기술학회지
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• 제16권2호
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• pp.118-129
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• 2013

Since the obstacles and mines are of the risk factors for operating ships and submarines, the active sonar system is inevitably used to avoid the hazards in ocean environment. In this paper, modeling and simulation algorithm is used for active sonar systemto quantify the measure of mission achievability, which is known as Measure of Effectiveness(MOE), specifically for detection in this study. MOE for detection is directly formulated as a Cumulative Detection Probability(CDP) calculated from Probability of Detection(PD) in range and azimuth. The detection probability is calculated from Transmission Loss(TL) and the sonar parameters such asDirectivity Index (DI) calculated from the shape of transmitted and received array, steered beam patterns, and Reverberation Level (RL). The developed code is applied to demonstrating its applicability.

• Wind and Structures
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• 제6권2호
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• pp.141-150
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• 2003

This paper presents galloping analysis of multiple-degree-of-freedom (MDOF) structural roofs with multiple orientations. Instead of using drag and lift coefficients and/or their combined coefficient in traditional galloping analysis for slender structures, this study uses wind pressure coefficients for wind force representation on each and every different orientation roof, facilitating the galloping analysis of multiple-orientation roof structures. In the study, influences of nonlinear aerodynamic forces are considered. An energy-based equivalent technique, together with the modal analysis, is used to solve the nonlinear MDOF vibration equations. The critical wind speed for galloping of roof structures is derived, which is then applied to galloping analysis of roofs of a stadium and a high-rise building in China. With the aid of various experimental results obtained in pertinent research, this study also shows that consideration of nonlinear aerodynamic forces in galloping analysis generally increases the critical wind speed, thus enhancing aerodynamic stability of structures.

• International Journal of CAD/CAM
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• 제5권1호
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• pp.11-18
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• 2005

The traditional method of manipulation of knots and degrees gives poor quality of surface, if compatibility of input curves is not good enough. In this work, a new algorithm of multiple refitting of curves has been developed using minimum energy based formulation to get compatible curves for skinning. The present technique first reduces the number of control points and gives smoother surface for given accuracy and the surface obtained is then skinned by compatible curves. This technique is very useful to reduce data size when a large number of data have to be handled. Energy based technique is suitable for approximating the missing data. The volumetric information can also be obtained from the surface data for analysis.

• 한국공간정보시스템학회:학술대회논문집
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• 한국공간정보시스템학회 2005년도 추계학술대회
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• pp.61-66
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• 2005

Spatiotemporal data mining represents the confluence of several fields including spatiotemporal databases, machine loaming, statistics, geographic visualization, and information theory. Exploration of spatial data mining and temporal data mining has received much attention independently in knowledge discovery in databases and data mining research community. In this paper, we introduce an algorithm Max_MOP for discovering moving sequences in mobile environment. Max_MOP mines only maximal frequent moving patterns. We exploit the characteristic of the problem domain, which is the spatiotemporal proximity between activities, to partition the spatiotemporal space. The task of finding moving sequences is to consider all temporally ordered combination of associations, which requires an intensive computation. However, exploiting the spatiotemporal proximity characteristic makes this task more cornputationally feasible. Our proposed technique is applicable to location-based services such as traffic service, tourist service, and location-aware advertising service.

• International Journal of Concrete Structures and Materials
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• 제4권1호
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• pp.45-49
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• 2010

The roller compacted concrete (RCC) is supposed to be isotropic, whereas the compaction of this material, which is achieved using the same machines used for the soil, appears only unidirectional, making the RCC an anisotropic material. In this experimental work, the influence of the phenomenon of compaction on the isotropy of the RCC is studied. This study was carried out through an evaluation of the compressive strengths and ultrasonic tests which were used for measurements of the elastic modulus and the dynamic Poisson's ratio of the RCC as well as a qualitative judgement of the RCC aspect at the hardened state. The results of this work proved the anisotropy of the RCC and they showed the sensitivity of the mechanical strengths and the elastic modulus to the compaction direction.

• Journal of electromagnetic engineering and science
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• 제12권1호
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• pp.55-62
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• 2012

Humanitarian demining is very important issue not only in mine affected courtiers but also for the courtiers which are technically, politically and financially supporting the mine affected courtiers. In order to achieve higher efficiency of the mine clearance operation, new technologies can significantly contribute to the societies. Since 2002, Tohoku University, Japan has developed a sensor system "ALIS" for humanitarian demining. ALIS is a hand-held dual sensor, which combines an electromagnetic induction sensor (EMI) and a Ground Penetrating Radar (GPR). ALIS has a real-time sensor tracking system based on a CCD camera and which enables the image reconstruction. We have tested ALIS in Cambodia and found that it can eliminate more than 70 % metal fragments. Since 2009, 2 sets of ALIS have detected more than 80 anti-personnel mines, and cleared more than 137,000 $m^2$ in Cambodia.

• 자원환경지질
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• 제33권6호
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• pp.557-563
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• 2000

Subsidence hazard has never been considered seriously until recent yews in Korea, although its socioeconomic impact on Korea becomes more and more enormous. There have been a few studies for the application of GIS analysis technique to the prediction of subsidence hazard. For GIS analysis, several factors, which are represented by coverage, are considered and selected for building a GIS model. Numerical method was used to quantify the importance of each factor in GIS model and the result from numerical modeling using FLAC was compared with that from previous research based on empirical methods. Analysis in 3-D needs more computer resources (i.e. memory). Therefore that in 2.5-D was considered to overcome the problem. Not only maximum vertical subsidence but also maximum horizontal strain and maximum slope have been considered for the assessment of subsidence hazard. The model can be easily modified for the purpose of applications in any subsidence area, especially cavern or abandoned mines under thick soil layer.