• Journal of the Korean Geophysical Society
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• v.7 no.1
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• pp.31-40
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• 2004

When surveying the cultural heritages especially in the case of stone structures, preserving their original state is of primary importance. For the effective assessment of survey results of stone structure, the dynamic characteristics of that system should be considered. Dynamic characteristics of stone masonry structures depend on several factors such as coefficients of friction, contact conditions, and number of layers of bonding stones. These factors can be estimated by using the dynamic analysis results. This paper describes a method for natural frequency determination of traditional stone arch bridge subjected to compressive force. For this purpose, multi-layered granite brick models of for arch bridge were made and fundamental frequencies corresponding increasing axial forces were measured.

• Korean Journal of Agricultural Science
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• v.38 no.1
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• pp.101-108
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• 2011

In forest work, working conditions are very hard to improve. The proper distribution of work time and good posture is believed to bring about direct improvements such as accident prevention. On this, this study has analyzed forest workers' posture and their working hours in order to improve their working conditions in stone channel work. Authors has chosen several core elements of stone channel work to focus on, which include stone masonry, excavation of bed, moving stone, directing work, choosing stone, and breaking stone. The ratio of real working time over total working time was shown as 84.6%. As for the time ratio of each elemental work over the real working time, the stone masonry was 60.4%, the directing work was 15.1%, moving stone was 12.1%, choosing stone was 7.1%, breaking stone was 3.3%, and excavation of bed was 2.0%. According to the analytical results provided by OWAS, the ratio of category III (Work posture has a distinctly harmful effect on the musculoskeletal system) has shown that moving stone turned out 65.2%, choosing stone was 61.5%, stone masonry was 46.1%, breaking stone was 14.3%, excavation of bed was 12.5% and directing work was 6.8%. Furthermore, the ratio of category IV (Work posture with an extremely harmful effect on the musculoskeletal system) has shown that excavation of bed turned out 37.5%, breaking stone was 28.6%, stone masonry was 27.3%, choosing stone was 7.7%, moving stone was 6.1% and directing working was 4.5%. These results are expected to be utilized for the improvement with respect to both working methods in the stone channel work and the workers' working posture.

• Journal of Technologic Dentistry
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• v.41 no.4
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• pp.287-293
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• 2019

Purpose: To evaluate the accuracy of the 3D printed die models and to investigate its clinical applicability. Methods: Stone die models were fabricated from conventional impressions(stone die model; SDM, n=7). 3D virtual models obtained from the digital impressions were manufactured as a 3D printed die models using a 3D printer(3D printed die models;3DM, n=7). Reference model, stone die models and 3D printed die models were scanned with a reference scanner. All dies model dataset were superimposed with the reference model file by the "Best fit alignment" method using 3D analysis software. Statistical analysis was performed using the independent t-test and 2-way ANOVA (α=.05). Results: The RMS value of the 3D printed die model was significantly larger than the RMS value of the stone die model (P<.001). As a result of 2-way ANOVA, significant differences were found between the model group (P<.001) and the part (P<.001), and their interaction effects (P<.001). Conclusion: The 3D printed die model showed lower accuracy than the stone die model. Therefore, it is necessary to further improve the performance of 3D printer in order to apply the 3D printed model in prosthodontics.

• Journal of Korean Association for Spatial Structures
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• v.8 no.5
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• pp.67-74
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• 2008

Multi-layered stone masonry monuments, such as stone pagoda can be modeled as a multi-degrees of freedom system. The dynamic behavior of these structures are mainly influenced by contour condition of contacting surface of stones. In this case the mass of the system can be easily estimated, mean while the estimation of stiffness at junction is not simple. In this paper a method for estimating the spring constant at the contacting surface of stone in proposed. This paper describes a method of computational modelling technique for structural analysis of stone pagodas using measurement of natural frequency and eigenvalue analysis. For this purpose Five story stone pagoda in Cchongnimsa site was selected as a model.

• Journal of the Korean Geosynthetics Society
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• v.5 no.1
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• pp.15-23
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• 2006

Sand Compaction Pile and Stone Column method have been used in widely during several decades as a technique to reinforce soft soils and increasing ultimate bearing capacity, accelerate consolidation settlement of the foundation ground. Stone column method, making a compaction pile using crushed stone, is a soft ground improvement method. However, stone column method is difficult to apply to the ground which is not mobilized enough lateral confine pressure because no bulging failure resistance. Hence, in present study, development the geogrid reinforced stone column system for settlement reduction and wide range of application of stone columns. To develop this system, triaxial compression tests were conducted for evaluation which is about behavior characteristics of stone column on replacement rate and confine pressure. Then, 3-dimensional numerical analysis were evaluated for application of the GRSC (geogrid reinforced stone column) system as evaluate behavior characteristics and settlement reduction effect of stone column reinforced by geogrid on types and reinforcing depth change of geogrid.

• Journal of the Earthquake Engineering Society of Korea
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• v.21 no.5
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• pp.237-244
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• 2017

This study proposes a numerical model to explain the closely placed double modes in the vibration of a layered stone pagoda system. The friction surface between the stones is modelled as the Timoshenko finite element while each stone layer is modelled as a rigid body. It is assumed that the irregular asperity on the friction surface enables the stone to be excited. This results in the closely placed modes that are composed of natural modes and self-excited modes. To examine the validity of the proposed model, a set of modal testing and analysis for a layered stone pagoda mock-up model has been conducted and a set of closely placed double modes are extracted. Applying the extended sensitivity-based system identification technique, the various system parameters are identified so that the modal parameters of the proposed numerical model are the same with those of the experimental mock-up. For a horizontal impulse excitation, the simulated acceleration responses are compared with measurements.

• Explosives and Blasting
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• v.22 no.1
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• pp.81-91
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• 2004

Samples examined in this paper were selected from Samwoo building stone, Sinra building stone, Gana building stone, and Chung gin building stone in Kyunggi province and Whakwang industry, Gomoch building stone, and Sejin building stone in Kyungbuk province. The point of this study is to examine the physical and mechanical features of Pochun rock, Munkyung rock and Ildong rock through specific gravity, porosity, absorption, point load test, triaxial compressive test Brazilian test, petrology test and chemical analysis test.

• Proceedings of the Korean Geotechical Society Conference
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• 2009.03a
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• pp.702-706
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• 2009

From the result of analysis the necessity of root fixing stone construction through the result of finite element method, following results were acquired. 1. The consolidation settlement by stone weight is small amount so that it is interpreted there is no stone settlement reducing effect by root fixing stone. 2. It is interpreted that there is no effect existence and nonexistence of the heaving soil to the settlement. 3. There is little settlement reducing effect by root fixing stone but there may be protection of excavation effect. Therefore, for long-term stability, installing the root fixing stone to the section where the typhoon effect directly would be proper.

• Journal of Conservation Science
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• v.35 no.1
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• pp.41-49
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• 2019

This study analyzes the material characteristics of stone tools of the Paleolithic period excavated from the Osong site, located at the project site for the creation of the Osong 2nd Life Science Complex, and estimates the provenance of the stone materials. Because the stones had been buried for a long time, their surfaces had become heavily weathered yellow or yellowish-brown, and the magnetic susceptibility values varied from 0 to 15(${\times}10^{-3}SI$). The excavated stone tools were rocks with various magnetic susceptibility values that could not be specified. Five stone tools subjected to destructive analysis were divided into two groups, one with a value of 1-3(${\times}10^{-3}SI$) and the other with a value of 5-9(${\times}10^{-3}SI$), both based on visible characteristics. The results of the thin-section analysis showed that most of the stone tools were basaltic rocks comprising plagioclase, quartz, and pyroxene, and some had iron content as high as 20 wt.%. These findings and the present geological map suggest that the stone tools were not made from the surrounding rocks because there are no areas containing basaltic rocks surrounding Bongsan-ri in Osong-eup. Andesite and tuff are distributed along with basaltic rocks in the Doan-myeon area in Jeongpyeong-gun, Chungcheongbuk-do Province, but the distance from the excavation site is too far. To determine whether this region is actually related to the provenance of the raw rock, it is necessary to conduct additional field surveys and comprehensive and precise analyses.

• Journal of Korean Society on Water Environment
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• v.21 no.4
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• pp.368-378
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• 2005

Inorganic matters originated from stone quarries and manufacturing plants could alter the ecological characteristics of adjacent aquatic systems, especially the structure and function of benthic macroinvertebrate community. In such situation, the locality of stone quarry and the quantity of inorganic matters would be important factors that determined the disturbing strength to the benthic macroinvertebrate community. Locality patterns of stone quarries were classified into 3 types in relation to the stream ecosystem; stream-proximity, upstream-inclusion and tributary-inclusion type. In the result of species:abundance analysis, stone quarry B (upstream-inclusion type) showed geometric distribution, while others showed broken-stick distribution pattern. The benthic macroinvertebrate communities closer to stone quarries showed smaller species numbers and standing crops among all types of stone quarries. However the values of species evenness index were not seriously different between controls and directly affected sites. These results indicated that the effect of inorganic disturbance would differ from those of organic pollution that induced the highly dominant state occupied by tolerant species. Number of occurred species, standing crops, community indices and biotic indices indicated that the community of upstream-inclusion type was the most seriously damaged from the inorganic disturbance, and the community would be very simple and unstable. Tributary-inclusion stone quarry heavily damaged to tributary system in biologically, but influence to the main stream seemed to be depended on the scale of main stream. Among 3 types of stone quarry localities, stream-proximity type induced the least damages to benthic macroinvertebrate community, though the degrees of damage were different along with distances between stream and stone quarry.