• Journal of the Korean Geographical Society
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• v.46 no.2
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• pp.115-133
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• 2011

Yamada's mountain ordering is to be said as an upward system, because the area and volume of the mountains become the larger as more than two lower order mountains constitute the higher order mountain. However, his mountain ordering shows some limitations to totally understand the mountain systems and to systematically manage the various kinds of mountainous informations. Because the independent third, fourth and so on, as well as the second lower order mountains are included in the higher order mountain. In order to solve the problem above, the downward system is suggested as the alternative of his upward system. The downward system means that the higher order mountain is classified into the second lower order mountains, and the second lower order mountain is classified into the third lower order mountains and finally the 2nd order mountain classified into the 1st order mountains. The method to classify a certain mountain systematically into all mountainous elements and the new nomenclature to be used for the classified elements are developed, using the downward system above. And the structure of database could be also suggested for the integrated and systematic management of mountain informations.

• Proceedings of the Korean Society of Disaster Information Conference
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• 2016.11a
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• pp.181-182
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• 2016

방조제 차수공사를 실시하는 현장 지반의 하부에 철재이물질과 돌망태 와이어 등이 매립되어 있는 것으로 확인된 상황에서 강널말뚝(sheet pile)을 풍화대까지 항타하는 것이 현실적으로 불가능하므로 상부는 철재이물질(돌망태 등)이 없는 심도까지 T-4 및 Vibro Hammer 에 의한 강널말뚝(sheet pile)을 이용하여 차수하고, 철재이물질과 돌망태 와이어 등이 매립되어 있는 것으로 확인된 하부 풍화대까지는 그라우팅에 의한 차수를 시도하는 현장차수방법을 시공하여 성공적으로 차수결과를 얻을 수 있었다.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.30 no.2
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• pp.61-68
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• 2018

This study was conducted to propose the optimum minimum requirement of cutoff system composed of the impermeable soil layer and vertical barrier in offshore landfill for prevention pollution leakage by seepage, advection, and dispersion numerical analyses under steady state. According to the study results, the minimum requirement of impermeable soil layer is below $1{\times}10^{-6}cm/s$ of hydraulic conductivity with more than 500 cm thickness or a system with equivalent cutoff effect. The minimum requirement of vertical barrier is below $1{\times}10^{-6}cm/s$ of hydraulic conductivity with more than 50 cm thickness or a system with equivalent cutoff effect. In addition, the vertical barrier should be embedded enough to seal securely with the impermeable soil layer for working cutoff effect.

• Journal of the Korean Geosynthetics Society
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• v.18 no.4
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• pp.97-106
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• 2019

This study was conducted to propose a reasonable requirement regulation of barrier system of rubble mound revetment offshore landfill for preventing contaminant leakage. The barrier is composed with bottom layer and side barrier. The bottom layer was assumed as impermeable clay layer and side barrier was composed with HDPE sheet (primary element) and mid-protection layer (supplementary element). Seepage-advection-dispersion numerical analysis has been conducted using SEEP/W and CTRAN/W programs under steady flow. As the results, the minimum required barrier regulations for hydraulic conductivity and thickness of the bottom layer were suggested. For side barrier, the extended length of HDPE sheet and the hydraulic conductivity of mid-protection layer were also suggested.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.5C
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• pp.351-358
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• 2006

The purpose of this study is to recommend the simulation method and procedure of behaviors of CFRD(Concrete Faced Rockfill Dam) concrete face slab with impoundment by centrifuge tests, to examine the effects of the flexural rigidity of the concrete face slab on the face slab deformation from the centrifuge tests, and to evaluate the effects of the stiffness of face supporting zone on the displacement and moment of face slab by numerical analysis which is verified by the centrifuge tests. In this study, the centrifuge tests on the two model dams with the concrete face slab of different flexural rigidity were carried out. Also, the centrifuge tests were simulated by numerical analysis of which input material properties were obtained by the triaxial tests on the model materials. The validity of numerical analysis was evaluated by comparison between the results of centrifuge tests and numerical simulation. The deformation pattern of the concrete face slab was examined with the various stiffness of the face supporting zone by numerical analysis. From the results of centrifuge tests, the effects of face slab thickness on the deformation of face slab were negligible. From the results of centrifuge tests and numerical analysis, it was found that the amplitude of the maximum displacement of face slab and the position where the maximum displacement was mobilized with impoundment were affected by the stiffness of face supporting zone rather than the flexural rigidity of concrete face slab.

• Journal of Soil and Groundwater Environment
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• v.7 no.1
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• pp.41-51
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• 2002

Recently, domestic waste landfills are constructed sometimes on seashore area to provide large landfill area. In order to strengthen the foundation of landfills and to prevent the infiltration of leachate through the bottom, many cases of constructing cement hardened liners on seashore clays are found. In these cases, it is possible to have cracks in the hardened liners due to settlement with waste load since the stiffness of the hardened liner Is greater than that of clay liners. In this study, the capability of Self-Sealing and Self-Healing (SSSH) liner made with a seashore clay in the metropolitan landfill to prevent the percolation of water and leachate is examined using flexible-wall permeameter test and using uniaxial compression test. Applicability of SSSH to weathered granitic soil is also examined for self-sealing capabilities. The result of Flexible permeameter test for SSSH with the seashore clay showed that permeability obtained was lower than permeability criteria of Korean waste management law. The permeability and strength characteristics of SSSH with granitic soil and bentonite showed better results than with the seashore clay.

• Journal of The Geomorphological Association of Korea
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• v.17 no.2
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• pp.1-13
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• 2010

The technique of mountain ordering developed by Yamada(1999) has been tested to two small islands (Namhaedo: 301km², Geojedo: 378km²). The results and experiences above were extended and applied to the whole area of the southern part of Korean Peninsula. Three areas such as Seorak-Taebaek Mountains, Jiri-Deogyu Mountains, and Youngnam Alps are identified as the highest, 5th order mountains. 10 areas are classified as the 4th order and 87 areas as the 3rd order. It is suggested that the 5th order mountains are related to the axis of uplift and the 4th and 3rd order mountains have the same direction (NE-SW) as that of the secondary mountain systems in the Korean Peninsula. The logarithmic values of number, area, and relative altitude of the ordered mountains have the linear relationship with the order, as the laws of stream order. The several mountains which are not included in the existing mountain systems could be identified among the ordered mountains, and those mountains could be used as the basis to understand the geological structure of the Korean Peninsula. Most of the National Parks and the Provincial Parks are distributed on the 3rd, 4th, 5th order mountains. It is especially confirmed that the Songnisan National Park take a role to link the Seorak-Taebaek Mountains and Jiri-Deogyu Mountains as a important ecological axis. Therefore, it would be validated that the technique of mountain ordering has the practical values as well as the geomorphological significances.

• Journal of KIISE:Computer Systems and Theory
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• v.26 no.8
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• pp.875-883
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• 1999

서로 다른 기하학적 모델링 시스템에 사용되는 곡선 및 곡면의 자료 교환에서, 시스템이 지원하는 그 곡선 및 곡면의 최대 차수에 제한이 있을 때, 낮은 차수로의 차수 감소가 필요하다. 본 논문에서는 근사 변환에 의한 B-spline 곡선의 차수 감소 방법을 제시한다. 기존의 Bzier 곡선의 차수감소 방법들을 적용하고, 그 방법들을 비교 분석한다. B-spline 곡선의 knot 제거 알고리즘이 자료 감소를 위해 차수 감소 과정에 적용된다.Abstract The degree reduction of B-splines is required in exchanging parametric curves and surfaces of the different geometric modeling systems because some systems limit the supported maximal degree. We propose an approximate degree reduction method of B-spline curves using the existing Bzier degree reduction methods. Knot removal algorithm is used to reduce data in the degree reduction process.

• Proceedings of the Korean Association of Geographic Inforamtion Studies Conference
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• 2008.10a
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• pp.203-204
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• 2008

EGM96 지구중력장모델을 개선시킨 EGM2008 지구중력장모델이 미국 NGA에 의해 발표됨에 따라, 본 연구에서는 EGM2008지구중력장모델을 한반도 지역을 대상으로 최대차수 360으로 해석하여 기존의 지구중력장모델인 EGM96(360차수) 및 EIGEN-GL04C(360차수)와 비교하였다. 또한 EGM2008은 기존의 구면조화분석한계인 360차수를 뛰어넘고 있으므로 격자 간격 $30'{\times}30'$ 및 $15'{\times}15'$, 그리고 $10'{\times}10'$로 각각 해석하여 지오이드고를 계산하고 정확도를 평가하였다. 정확도 평가는 우리나라의 수준점에서 GPS측량을 실시한 464점의 GPS/leveling 데이터를 활용하였다. 평가결과 EGM2008(360차수)은 $-0.100{\pm}0.183m$를 나타내 EGM96(360차수)결과인 $0.156{\pm}0.238m$에 비해 상당한 정확도의 개선을 가져왔으며, 2190차수의 고차항으로 해석한 결과 $-0.069{\pm}0.140m$ 더욱 정확한 결과를 얻을 수 있음을 확인하였다.

• The Journal of the Korea institute of electronic communication sciences
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• v.11 no.1
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• pp.81-86
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• 2016

Three hundred years ago, the fractional differential equation that is one of concept of fractional calculus released. Now, many researchers continue to try best effort applying into the control engineering, mathematics and physics. In this paper, the dynamics equation which is represented by Van der Pol, represent integer order and fractional order that having real order. Then this paper performs the comparisons between integer and real order as time series and phase portrait according to variation of parameter value for real order.