• Journal of the Korean Data and Information Science Society
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• v.22 no.4
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• pp.691-699
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• 2011

Land sliding is one of well-known nature disaster. As a part of effort to reduce damage from land sliding, many researchers worked on increasing prediction ability. However, because previous studies are conducted mostly by non-statisticians, previously proposed models were hardly statistically justifiable. In this paper, we predicted the probability of land sliding using the logistic regression model. Since most explanatory variables under consideration were correlated, we proposed the final model after backward elimination process.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10b
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• pp.771-774
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• 1996

This paper presents a continuous time varying sliding surface that allows faster tracking and really guarantees robust contro land smooths control inputs. And this method is evaluated by applying to robot manipulator.

• The KSFM Journal of Fluid Machinery
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• v.9 no.5 s.38
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• pp.7-13
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• 2006

In the present study, we develop an analysis module to be applicable to design of sliding thrust bearings. The pressure equation is solved by using the finite element method. Average lubricant temperature is obtained from using the energy balance method. The module developed has been applied to three types of thrust bearing, such as tapered-land thrust bearings of angular and diamond types, and tilting-pad thrust bearings. Effects of the dam of the tapered-lad thrust bearings have also been investigated. It has been seen that the tapered-land thrust bearings of angular type result in the highest load capacity, while the tilting pad thrust bearings result in the lowest lubricant temperature. It has also been seen that the dam in the tapered-land thrust bearings increases both the load capacity and lubricant temperature.

• Tribology and Lubricants
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• v.13 no.1
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• pp.21-27
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• 1997

The friction and wear behavior of undulated surfaces made of tin base babbit are examined experimentally at the low sliding speed with severe loading condition. Steel is used as counterface disk material under pin-on-disk type sliding condition. Undulated surfaces can improve the friction and wear properties under dry friction condition since undulated surfaces trap wear particles in their cavities and prohibit wear particles from agglomerating. However, under boundary lubrication condition, friction and wear properties of undulated surfaces are inferior to those of flat surfaces. It is shown that land width and the ratio of wear volume to cavity volume are the most important factors in friction behavior of undulated surfaces under dry friction condition, and there exists optimum land width minimizing friction and wear of undulated surfaces.

• Proceedings of the Korean Geotechical Society Conference
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• 2008.03a
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• pp.875-883
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• 2008

The amount of granite distribution area occupies about 40 - 50% of Korean Peninsula. The granite irregularly Intruded through preCambrian to Tertiary times but in Jurassic time so called, Daebo granite most widely crops out in Korean Peninsula. In addition to Bulkuksa Grante which intruded at Cretaceous time crops out at the southern part of Korean Peninsula and in northern part Triassic Songrim Granite is distributed. These granites have equigranular texture and are relatively isotropic. Their uniaxial compressive strength is above $1,500kg/cm^2$ and also seismic velocity is over 2,000m/sec. When these rocks receive a weathering action, the feldspar weathers first and the quartz grains remain plentifully to make the "Masato(Korean name)". Also when the granite receives a weathering action, quite often it make sheeting joint which is topographically parallel to the earth surface and also make a (so called, onion structure. These weathering phenomena easily make a land sliding when it is heavy rain and weathering surface is irregular.

• The Journal of Engineering Geology
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• v.31 no.3
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• pp.269-281
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• 2021

Land creeping is the imperceptibly slow, steady, downward movement o f slope-forming soil or rock. Because creep-related failures occur frequently on a large scale without notice, they can be hazardous to both property and human life. Korea Forest Service has operated the prevention and response system from land creeping which has been on the rise since 2018. We categorized and proposed three survey steps (e.g., preliminary, regional, detailed) for investigation of creeping susceptibility site with a focus on geophysical mapping of a selected test site, Yongheung-dong, Pohang, Korea. The combination of geophysical (dipole-dipole electrical resistivity tomography and reciprocal seismic refraction technique, well-logging), geotechnical studies (standard penetrating test, laboratory tests), field mapping (tension cracks, uplift, fault), and comprehensive interpretation of their results provided the reliable information of the subsurface structures including the failure surface. To further investigate the subsurface structure including the sliding zone, we performed high-resolution geophysical mapping in addition to the regional survey. High-resolution seismic velocity structures are employed for stability analysis because they provided more simplified layers of weathering rock, soft rock, and hard rock. Curved slip plane of the land creeping is effectively delineated with a shape of downslope sliding and upward pushing at the apex of high resistive bedrock in high-resolution electrical resistivity model with clay-mineral contents taken into account. Proposed survey steps and comprehensive interpretation schemes of the results from geological, geophysical, and geotechnical data should be effective for data sets collected in a similar environment to land-creeping susceptibility area.

• Journal of the Korean Geotechnical Society
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• v.38 no.5
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• pp.19-33
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• 2022

Newmark's sliding block analysis is the most commonly used method for predicting earthquake-induced permanent displacement of embankment slopes. Additionally, it yields the amount of slip circle sliding using the limit equilibrium theory. Thus, permanent displacement does not occur until the seismic load exceeds the yield acceleration, which induces sliding of the slip circle. The evolution of Newmark's sliding block analysis has been made by introducing the numerical seismic response analysis results since it was introduced. This study compares seismic performance evaluation results for the example enclosure dam section with the analysis methods. As a result, earthquake-induced permanent displacement using Newmark's sliding block analysis did not occur for the enclosure dam, indicating a high safety factor. However, nonlinear response history analysis gave reasonable results.

• Journal of Korean Society on Water Environment
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• v.26 no.4
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• pp.691-699
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• 2010

In recent years, increases in impervious areas with rapid urbanization and land use changes are causing numerous hydrologic cycle and environmental problems. Impermeable pavement have a various defect such as collection rainwater, decreasing of sliding resistance, and etc. In this study, the hydrologic cycle effect of permeable pavement were analyzed by the experiment and the numerical simulation. The numerical model used was a modified SWMM especially for considering the hydrologic cycle effect of permeable pavement. The parameters of modified SWMM were revised by the experimental results. Also, the effects of runoff quantity reduction are reviewed when permeable pavement is applied to Incheon Cheongna watershed. The hydrologic cycle analysis of Incheon Cheongna watershed, continuous simulations of urban runoff were performed. The analysis results of permeable pavement setup effect on runoff are follows: the surface runoff after permeable pavement setup decreases to 74.35% of the precipitation whereas the surface runoff before permeable pavement setup amounts to 81.38% of the precipitation; the infiltration after permeable pavement setup increases to 15.13% of the precipitation whereas the infiltration before permeable pavement setup amounts to 8.32% of the precipitation.

• Korean Journal of Agricultural Science
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• v.25 no.1
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• pp.97-106
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• 1998

This study was carried out to investigate the problem of analysis method of circular sliding, which uses a high rate to work out a countermeasure for landslides. The results of this study were summarized as follows : 1. As a result of the analysis of sliding surface along the soil layers in forty model slopes, the boundary layer in weathered soil and weathered rock indicated a very high possibility of sliding than in other places. 2. Because most landslides in Korea occur along the discontinuity face at the boundary of soil layers, below 2m. from land surface, it is a good method for safe design to work the countermeasure for these kinds of landslides in cutting slopes. 3. When the inclination of slopes is fixed and the length of slopes is changed, the cercular sliding slopes were more safe as the soil layers are more shallow and the length of slopes are shorter, but the safety ratio of infinite sliding slopes was same as the other even though their length of slopes was different. 4. As a result of the analysis by cercular sliding analysis method and infinite sliding analysis method with some condition that the inclination of slopes was $30^{\circ}$ degree, because most landslides in Korea occur at this condition, these methods indicated different results to each other as well as cercular sliding analysis method showed too much safety ratio than infinite sliding analysis method.

• Transactions of Materials Processing
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• v.18 no.7
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• pp.565-571
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• 2009

This paper is concerned with the analysis on the surface stress profiles of perfectly plastic material in backward extrusion process. Due to heavy surface expansion appeared usually in the backward extrusion process, the tribological conditions along the interface between the material and the punch land are very severe. In the present study, the analyses have focused to reveal the surface conditions at the contact boundary for various punch shapes in terms of surface expansion, contact pressure, and relative movement between punch and workpiece which consists of sliding velocity and distance, respectively. Punch geometries adopted in the analysis include concave, hemispherical, pointed and ICFG recommended shapes. Extensive simulation has been conducted by applying the rigid-plastic finite element method to the backward extrusion process under different punch geometries. The simulation results are summarized in terms of surface expansion, contact pressure, sliding velocity and sliding distance at different reduction in height, deformation patterns, and load-stroke relationship, respectively.