• Geotechnical Engineering
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• v.12 no.6
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• pp.37-50
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• 1996

In this study, we collected data through the investigation of rock slopes of highway. By analyzing the collected data, the main factors of rock slope failure were studied. We studied on the failure types and scales according to rock types and geological structures in many rock slopes of highway. As a result, it was shown that many failed slopes were distributed in the areas of Cretaceous sedimentary rocks of south-eastern part in the Korean Peninsula and the Gneiss Complex in both Kyonggi-Do and Kangwon-Do. According to rock types, the following slope failure types were shown : that igneous rocks had the types of rock fall, plane failure, soil erosion and circular failure but had low failure frequency, and sedimentary rocks had predominantly the type of plane failure. Metamorphic rock showed the types of circular failure, wedge failure and plane failure due to poor rock qualities . According to geological structures, the following slope failure types were shown slope failure in igneous rocks was caused by joints, and in sedimentary rocks by bedding plane, and in metamorphic rocks by faults and poor rock qualities.

• Journal of Dental Rehabilitation and Applied Science
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• v.29 no.2
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• pp.163-173
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• 2013

When the mandible performs opening movement, the condyle-disk complex conducts sliding movement along the articular eminence. Thus, anatomic configuration of articular eminence is very important to normal movement of TMJ. The purpose of this study was to measure the posterior slope of the articular eminence and evaluate the effect of a pathologic bone change in the condylar head on the stiffness of articular eminence, and compare the differences of the articular eminence slope by gender and age using dental cone-beam CT. As using i-CAT Cone-Beam Computed Tomography, the CT images of 204 TMJs of 102 patients(43 men and 59 women, mean age: 37.7 years) who were diagnosed at Wonkwang University Sanbon Dental Hospital were evaluated. All images were converted into a TMJ analysis mode to observe the continuous sagittal section images and coronal section images of the joints. To observe and assess bone changes in the condyle, three dentists measured the stiffness of the articular eminence on the same images, and when two of the three dentists agreed on their reading, these results were adopted and recorded. The articular eminence slope, considering the condylar anatomic configuration, was measured in three regions, namely, lateral part, central part, and medial part of the condyle. In the cases of a normal condyle(NCBC) and a condyle(CBC) with bone change, the articular eminence slopes were $57.0^{\circ}$(NCBC) and $51.8^{\circ}$(CBC) at the medial part, $57.9^{\circ}$(NCBC) and $52.4^{\circ}$(CBC) at the central part, and $55.1^{\circ}$(NCBC) and $49.5^{\circ}$(CBC) at the lateral part of the condyle. And the articular eminence slope of the condyle with bone change demonstrated less steepness than that of normal condyle (p<0.05). The articular eminence slope showed mediolaterally that it was the steepest at the central, followed by at the medial, and at the lateral (p<0.05). There were no significant differences by the gender and the age (p.0.05).

• Korean Journal of Environment and Ecology
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• v.12 no.4
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• pp.373-380
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• 1999

The Byokryon-Daejangbong valley forest in Keumsan area at Hallyo-Haesang National Park was studied to investigate forest structure in relation to altitude and part of the slope. Forty-eight quadrats were set up in the valley forest along altitude of 200m to 650m and part of the slope. Density, mean DBH, and basal area of the canopy trees were 820~1873trees/ha, 10.7~14.6cm, and 17.7~22.2$\m^2$/ha, respectively. With increasing elevation mean DBH and basal area of tree stratum increased while density of tree stratum decreased. As elevation increased the importance values of Quercus mongolioa, Styrax japonica, Acer pseudo-sieboldiannum, and Sorbus alnifolia increased while those of Pinus thunbergii, Pinus densiflora, Prunus sargentii, Cornus kousa, and Eurya japonica decreased. The importance values of Fraxinus sieboldiana, Quercus variabilis, and Sorbus alnifolia increased as going from lower part to upper part of the slope. However, the opposite trend was found for the importance values of Styrax japonica, Lindera erythrocarpa, and Zelkova serrata, With incresing elevation number of species, species diversity, and evenness incresed and it was suggested that man interference was relatively severe. The range of similarity indices between elevation belts and between parts of the slope were 42.0~71.8% and 74.8~76.8%, respectively. According to importance values and cluster analysis, the studied valley forest was classified into four forest communities of Quercus serrata-Pinus densiflora community in low elevation belt, Carpinus laxiflora-deciduous tree species community in high elevation belt and lower and middle parts at middle elevation belt, Quercus variabilis-Carpinus laxiflora community in upper part at middle elevation belt, and Quercus mongolica-Styrax japonica community in top area. There were significantly positive correlation among Quercus serrata, Pinus densiflora, Pinus thunbergii, and Eurya japonica and among Carpinus laxiflora, Zelkova serrata, and Cornus walteri.

• Journal of Korean Tunnelling and Underground Space Association
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• v.21 no.5
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• pp.621-640
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• 2019

Quantitative stability assessment of underground cavities can be presented as a factor of safety based on the Shear Strength Reduction Method (SSRM). Also, SSRM is one of the stability evaluation methods commonly used in slope stability analysis. However, there is a lack of research that considers the relationship between the probability of occurrence of cavities in the ground and the potential failure surface of the slope at the same time. In this study, the effect of small underground cavities on the failure behavior of the slope was analyzed by using SSRM. Considering some of the glaciology studies, there is a case that suggests that there is a cavity effect inside the glacier in the condition that the glacier slides. In this study, the stability evaluation of underground cavities and slope stability analysis, where SSRM is used in geotechnical engineering field, was carried out considering simultaneous conditions. The slope stability analysis according to the shape and position change of underground cavities which are likely to occur in the lower part of a mountain road was analyzed by using SSRM in FLAC3D software and the influence of underground cavities on the slope factor of safety was confirmed. If there are underground cavities near slope potential failure surface, it will affect the calculation of a factor of safety. The results of this study are expected to be basic data on slope stability analysis with small underground cavities.

• The Journal of Engineering Geology
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• v.22 no.1
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• pp.1-13
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• 2012

The purpose of this work is to gain a better understanding of the interrelationships between geological structures and slope failure in sedimentary rocks. In the studied slopes, construction-related slope failure could only be observed on the south-dipping slopes. This indicates that slope stability may be dependent on the angular relationships between the dip direction of bedding and the orientation of the slope. Slope failure continued, post-construction, around large fault zones in the studied outcrop; these fault damage zones are, however, not easily recognized in the field. Here we suggest a new method that uses accumulated fracture density to precisely identify fault damage zones. Multiple-faced slopes are now increasingly being exposed during large-scale construction projects in South Korea. This multiple-faced slope analysis indicates that the stability of a slope should be evaluated by identifying domains, through the analysis of possible slopes and their angular relationships with bedding and other discontinuities, prior to construction. Therefore, careful consideration of geological structures such as bedding and other discontinuities, and their angular relationships during the design of cuttings through sedimentary rocks, will increase the efficiency of construction and enable the safe construction of more stable slopes that will retain their stability after construction.

• Proceedings of the Korean Society of Environment and Ecology Conference
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• 2000.04a
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• pp.153-155
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• 2000

• Proceedings of the Korean Society of Environment and Ecology Conference
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• 1999.04a
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• pp.124-125
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• 1999

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.31 no.1
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• pp.8-14
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• 1995

The behaviour of large school of sardine Sardinops melanosticta in and around the set-net were analyzed from sonar image recordings. The survey was conducted at Kishihata set-net in Japan from January 29th to February 22th 1992. The results obtained are summarized as follows ; 1. When large schools of sardine moved along the outside of the set-net. the shape of the school gradually changed, that was the front part extended forward in the direction of movement and the rear part concentrated in the same direction such that the school retained its original shape. 2. When large school of sardine entered the main-net of the set-net. the school was decentralized directly to the slope-net. to the central part. and to the opposite side, and then the fish school was concentrated as it moved directly to the slope-net. 3. When the size of the front part of the fish school enlarged. the maximum recorded moving speeds were 176cm/sec and 277cm/sec for schools inside and outside the set-net, respectively.

• Journal of Korean Tunnelling and Underground Space Association
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• v.2 no.2
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• pp.50-61
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• 2000

The ground around the portal of a tunnel is the most typical part showing the 3-dimensional mechanical behavior in the tunnel. The portal slope is constructed at the weathered soft rock-mass, and remains as a potential sliding mass. The slope failure around the tunnel portal may happen drastically and induce the great disaster; hence, for the permanent stability several special techniques are required. To solve this problem, the ground around the tunnel portal may be excavated in the arch shape to develop the arching effect in horizontal direction. With the arch-type portal slope, one can reduce considerably the excavation mass and the damage of environments. This approach has not been attempted yet due to the lack of understanding and the well-defined analyzing method, so the retaining wall type portal is more universal. The 3-dimensional finite element analyses were carried out to prove that the arch type is more advantageous in safety and cost than the right angle type. The influence of the tunnel construction sequence and the strength of the rock-mass on the slope stability was investigated by focusing on the maximum shear strain in the slope, and the yield zone at the tunnel face.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.30 no.11 s.254
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• pp.1461-1471
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• 2006

This paper presents the mathematical model for rolling behaviors of a small regular polygonal part on an inclined plane. Throughout the numerical analysis performed with the simulation program which has been experimentally validated, it is shown that the number of edges of the rolling polygonal part can be a measure for the energy dissipation rather than the coefficient of friction. The appropriate slope angle has been found to be around 20 degree for roughness-separation as well as shape-separation of polygonal parts which have small number of edges. In additions, the vibratory motion applied to the inclined plane is able to cause mixed parts to be separated more effectively according to the shape or the roughness. Finally, a couple of parts separation methods based on the analysis results are presented, and are validated through the numerical simulation.