• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2005.05a
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• pp.395-400
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• 2005

Nano-scale fabrication of silicon substrate based on the use of atomic force microscopy (AFM) was demonstrated. A specially designed cantilever with diamond tip, allowing the formation of damaged layer on silicon substrate by a simple scratching process, has been applied instead of conventional silicon cantilever for scanning. A thin damaged layer forms in the substrate at the diamond tip-sample junction along scanning path of the tip. The damaged layer withstands against wet chemical etching in aqueous KOH solution. Diamond tip acts as a patterning tool like mask film for lithography process. Hence these sequential processes, called tribo-nanolithography, TNL, can fabricate 2D or 3D micro structures in nanometer range. This study demonstrates the novel fabrication processes of the micro cantilever and diamond tip as a tool for TNL using micro-patterning, wet chemical etching and CVD. The developed TNL tools show outstanding machinability against single crystal silicon wafer. Hence, they are expected to have a possibility for industrial applications as a micro-to-nano machining tool.

• Agricultural and Biosystems Engineering
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• v.1 no.1
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• pp.7-15
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• 2000

Optimization was considered from three perspectives : minimum grain loss, minimum damaged grain loss, and minimum power consumption. Factors affecting combine performance were classified as control, adjustable, and environmental. Control and adjustable factors were optimized by the parameter design developed by Taguchi. Environmental factors were used as input for optimization. Optimum range for control and adjustable factors are presented. Parameter design was adequate to obtain the optimum levels of control factors and optimum range of adjustable factors.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 1993.10a
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• pp.714-726
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• 1993

Optimization was considered from three perspectives ; minimum grain loss, minimum damaged grain loss, and minimum power consumption. Factors affecting combine performance were classified as control , adjustable , and environmental. Control and adjustable factors were optimized by the parameter design developed by Tajuchi. Environmental factors were used as input for optimization Optimum range for control and adjustable factors are presented. Parameter design was adequate to obtain the optimum levels of control factors and optimum range of adjustable factors.

• Journal of People, Plants, and Environment
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• v.22 no.6
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• pp.641-651
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• 2019

The purpose of this study is to derive institutional improvement methods for promoting the Damaged Area Restoration Project in greenbelts. The current status of greenbelts in Gyeonggi-do, where greenbelts are extensively distributed was analyzed, and the relevant laws and regulations were reviewed to suggest measures to promote the restoration project. The area of damaged areas within greenbelts in Gyeonggi-do was 6,121,024 m², accounting for about 0.52% of the total area of greenbelts, and more than 80% was found to be located in Namyangju (55.49%), Hanam (16.48%), and Siheung (8.68%). Various measures to improve the policy were examined as follows: reducing the minimum size of the restoration project area; adjusting baseline of recognizing range of damaged areas; introducing the right of claim for land sale; allowing long-term unexecuted urban parks to be replaced as alternative sites for parks and green spaces; simplifying administrative procedures; and allowing public participation. All of them are expected to promote the restoration project within greenbelts. In results, when the minimum size of area for the restoration project was reduced from 10,000 m² into 5,000 m², 3,000 m² and 2,000 m², the ratio of the number of combinable lots to the total number of lots increased from 4.4% to 18.8%, 38.8%, and 55.9% respectively in Namyangju. Morever, when the recognizable ranges of the restoration project were extended to the structures obtaining building permit as of March 30, 2016 and obtaining use approvals before December, 2017, the number of applicable lots increased by 5.1% and 9.2% respectively.

• Geomechanics and Engineering
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• v.24 no.4
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• pp.323-335
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• 2021

This paper aims to estimate the range of the excavation damaged zone (EDZ) formation caused by the tunnel boring machine (TBM) advancement through dynamic three-dimensional large deformation finite element analysis. Large deformation analysis based on Coupled Eulerian-Lagrangian (CEL) analysis is used to accurately simulate the behavior during TBM excavation. The analysis model is verified based on numerous test results reported in the literature. The range of the formed EDZ will be suggested as a boundary under various conditions - different tunnel diameter, tunnel depth, and rock type. Moreover, evaluation of the integrity of the tunnel structure during excavation has been carried out. Based on the numerical results, the apparent boundary of the EDZ is shown to within the range of 0.7D (D: tunnel diameter) around the excavation surface. Through series of numerical computation, it is clear that for the rock of with higher rock mass rating (RMR) grade (close to 1st grade), the EDZ around the tunnel tends to increase. The size of the EDZ is found to be direct proportional to the tunnel diameter, whereas the depth of the tunnel is inversely proportional to the magnitude of the EDZ. However, the relationship between the formation of the EDZ and the stability of the tunnel was not found to be consistent. In case where the TBM excavation is carried out in hard rock or rock under high confinement (excavation under greater depth), large range of the EDZ may be formed, but less strain occurs along the excavation surface during excavation and is found to be more stable.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.19 no.1
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• pp.121-133
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• 2016

It was required to evaluate ecological restorations in a comprehensive way in order to systematically manage conservation areas such as DMZ and national parks in South Korea. In this research we developed a new approach to evaluating ecological restorations with more various indexes than vegetation covering-related indexes. By analyzing damaged areas in the vicinity of DMZ, major damaged types were identified as six classes: landform modification, surface loss, soil pollution, soil physio-chemical modification, vegetation decline and vegetation damaged. From literature review, 39 indexes were selected and were grouped into four divisions: soil property, vegetation growth & structure, habitat property and landscape structure & functions. By conducting a survey with the selected indexes targeting relevant experts, data on relative importance among the divisions and indexes by damaged type were collected. As a result, it was found that the orders and values of weighted values of the divisions were different by damaged type: for example, soil property (0.402), vegetation growth & structure (0.209), habitat property (0.225), landscape structure & function (0.163) for "landform modification"; but soil property (0.171), vegetation growth & structure (0.401), habitat property (0.270), landscape structure & function (0.158) for "vegetation decline". Similarly, evaluation indexes showed different orders and values of relative importance, easiness in field measurement and representativeness for the division by damaged type, and the values were used for calculating importance factor for each index. In the evaluation table, score1 and score2 were made by the importance factors of indexes multiplied by distribution values which present grades and by the weighted values of divisions. In conclusion, while dealing with the damaged type was considered significant for evaluating and managing restorations, further tests on this table with a range of cases were needed to improve its quality.

• Computers and Concrete
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• v.22 no.2
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• pp.143-152
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• 2018

This paper deepens the finite element modeling (FEM) method to reproduce the compressive behavior of partially steel-jacketed (PSJ) RC columns by means of the Concrete Damaged Plasticity (CDP) Model available in ABAQUS software. Although the efficiency of the CDP model is widely proven for reinforced concrete columns at low confining pressure, when the confinement level becomes high the standard plasticity parameters may not be suitable to obtain reliable results. This paper deals with these limitations and presents an analytically based strategy to fix the parameters of the Concrete Damaged Plasticity (CDP) model. Focusing on a realistic prediction of load-bearing capacity of PSJ RC columns subjected to monotonic compressive loads, a new strain hardening/softening function is developed for confined concrete coupled with the evaluation of the dilation angle including effects of confinement. Moreover, a simplified efficient modeling approach is proposed to take into account also the response of the steel angle in compression. The prediction accuracy from the current model is compared with that of existing experimental data obtained from a wide range of mechanical confinement ratio.

• Proceedings of the Korea Concrete Institute Conference
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• 2000.04a
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• pp.757-762
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• 2000

The target of this study is to compare and analyze the strengthening effect of damaged reinforced concrete beams under unloading and loading conditions through the simulation of strengthening condition in real structures. The conclusion of test results are as follows : For the concrete beam wrapped at the side in addition to be strengthened at the bottom, the strength and stiffness increase. although the flexural capacity depends on the strengthening method, it generally shows that the strength improve in the range of 22% to 39% in comparison with the specimen without strengthening. In case of applying th equation suggested by CangaRao & Vijay for the wraped concrete beam, it must be modified because it is likely to overestimate the flexural capacity considering the height of wrapping as the width of concrete. The strength an stiffness of reinforced concrete beams in proportion to the percentage of damage decrease. Damaged beams, which are strengthened by CFS, is structurally efficient and show reduction of strength comparing with the specimen without strengthening but stiffness is increasing.

• Structural Monitoring and Maintenance
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• v.1 no.3
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• pp.339-356
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• 2014

This study has been motivated to evaluate the practicality of numerical simulation of impedance monitoring for damage detection in steel column connection. In order to achieve the objective, the following approaches are implemented. Firstly, the theory of electro-mechanical (E/M) impedance responses and impedance-based damage monitoring method are outlined. Secondly, the feasibility of numerical simulation of impedance monitoring is verified for several pre-published experimental examples on steel beams, cracked aluminum beams, and aluminum round plates. Undamaged and damaged steel and aluminum beams are simulated to compare to experimental impedance responses. An aluminum round plate with PZT patch in center is simulated to investigate sensitive range of impedance responses. Finally, numerical simulation of the impedance-based damage monitoring is performed for a steel column connection in which connection bolts are damaged. From the numerical simulation test, the applicability of the impedance-based monitoring to the target steel column connection can be evaluated.

• Journal of the Korean Association of Geographic Information Studies
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• v.4 no.4
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• pp.72-78
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• 2001

In this study, high spatial resolution of IKONOS 1m image and Red(0.63~0.69) band, NIR(0.76~0.90) band in 4m image, which are the same wavelength range as Landsat TM band 3, 4, were used for extraction of the front areas of B. Xylophilus in Geuje island where is located in southern part of Korea. Moreover, since they have higher spatial resolutions than Landsat TM, they have been used for lots of studies in the field of forest and vegetation. In the results, it was validated by GPS field survey, spectral histogram analysis of IKONOS NIR band was significant available method for extracting the front areas of B. Xylophilus. In this study, 15 points were verified as real damaged trees of 22 sample points extracted from GPS field survey. This study was not only extracted the damaged trees by B. Xylophilus but also suggested the possibility of using IKONOS images for the study on the forest damages by any disease and insect pests.