• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1999.05a
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• pp.415-421
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• 1999

This paper indicate that phase resolved partial discharge patterns are investigated on PET films containing artificial void of varing dimensions. In this study, we measured phase-resolved PD patterns and statistical parameter from PET specimens with IGT(insulation/airgap/insulation) structure by IEC 270 standard. Measurement system is the conventional PD detector using digital signal processing technique. The relationship of diameter and location of artificial void was discussed through the difference of $\pi$-q-n distribution and statistical analysis.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2015.05a
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• pp.171-172
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• 2015

Recently, it is the global warming phenomenon because of the greenhouse gas exhaustion caused by and the environment problem is serious. And it is the situation where the problem of the exhaustion of resource because of the indiscriminate picking of the that is the raw material of the cement, limestone and natural aggregate are emphasized. In addition, thus the cement reduction amount of use and substitute material research is the urgent actual condition with the gas emission, which here it is generated in conducting compression molding in the building stone manufacturing process performance degradation phenomenon and fire resistance, and problem of the durability. Therefore, in this research, the waste porcelain is applied to the artificial stone and the durability property of the artificial stone according to it tries to be investigated.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.36 no.4
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• pp.259-264
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• 2023

In this study, we devised a parametric analysis workflow for efficiently analyzing the material properties of 3D woven materials. The parametric model uses wire spacing in the woven materials as a design parameter; we generated 2,500 numerical models with various combinations of these design parameters. Using MATLAB and ANSYS software, we obtained various material properties, such as bulk modulus, thermal conductivity, and fluid permeability of the woven materials, through a parametric batch analysis. We then used this large dataset of material properties to perform a regression analysis to validate the relationship between design variables and material properties, as well as the accuracy of numerical analysis. Furthermore, we constructed an artificial neural network capable of predicting the material properties of 3D woven materials on the basis of the obtained material database. The trained network can accurately estimate the material properties of the woven materials with arbitrary design parameters, without the need for numerical analyses.

• Computers and Concrete
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• v.31 no.4
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• pp.327-335
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• 2023

The most popular building material, concrete, is intrinsically linked to the advancement of humanity. Due to the ever-increasing complexity of cementitious systems, concrete formulation for desired qualities remains a difficult undertaking despite conceptual and methodological advancement in the field of concrete science. Recognising the significant pollution caused by the traditional cement industry, construction of civil engineering structures has been carried out successfully using Geopolymer Concrete (GPC), also known as High Performance Concrete (HPC). These are concretes formed by the reaction of inorganic materials with a high content of Silicon and Aluminium (Pozzolans) with alkalis to achieve cementitious properties. These supplementary cementitious materials include Ground Granulated Blast Furnace Slag (GGBFS), a waste material generated in the steel manufacturing industry; Fly Ash, which is a fine waste product produced by coal-fired power stations and Silica Fume, a by-product of producing silicon metal or ferrosilicon alloys. This result demonstrated that GPC/HPC can be utilised as a substitute for traditional Portland cement-based concrete, resulting in improvements in concrete properties in addition to environmental and economic benefits. This study explores utilising experimental data to train artificial neural networks, which are then used to determine the effect of supplementary cementitious material replacement, namely fly ash, Ground Granulated Blast Furnace Slag (GGBFS) and silica fume, on the compressive strength, tensile strength, and modulus of elasticity of concrete and to predict these values accordingly.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1997.04a
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• pp.301-304
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• 1997

Effects of volatile impurities on deterioration characteristics of XLPE were investigated. Block type plate with needle-plane electrode and artificial void filled with $N_2$gas or humidity was subjected under high electric field. The dyed region by oxidation reaction around the artificial void filled with humidity was detected before tee initiation. Electrical tree was started from the tip of void filled with $N_2$gas earlier than humidity.

• Journal of the Korean Ceramic Society
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• v.47 no.5
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• pp.445-449
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• 2010

The purpose of this study is to improve recycling rate of the waste glasses by investigating bloating mechanism. In this study, we use waste glass(W/G) and hard clay(H/C) as raw materials. The artificial lightweight aggregates were formed by plastic forming($\phi$=10 mm) and sintered by fast firing method at different temperatures(between 700 and $1250^{\circ}C$). The physical properties of the aggregates such as bulk specific gravity, adsorption and microstructure of surface and cross-section are investigated with the sintering temperature and rate of W/G-H/C contents. As the result of the bulk specific gravity graphs, we can found out the inflection point at content of W/G 60 wt%. From the microstructure images, we considered the artificial lightweight aggregates content of W/ G over 60wt% are distributed numerous micro-pores by organic oxidation without Black Core and the artificial lightweight aggregates of W/G below 60 wt% are distributed macro-pores with Black Core.

• Korean Journal of Environment and Ecology
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• v.35 no.3
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• pp.256-264
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• 2021

Rapid urbanization around the world has negatively affected wildlife habitats, including birds. Wild birds settled in the city are adapting to the changed surroundings, and are typically known to make nests using materials that are easy to find around the city. This study was conducted for the purpose of analyzing the nesting materials on the Paridae using artificial bird nests installed in cities. In this study, the researchers established a total of 33 artificial bird nests in urban parks (22) and forests (11) in Cheonan-si, Chungcheongnam-do. Then we collected 4 artificial bird nests in urban parks (18.19%) and 5 in urban forests (45.46%) to compare the characteristics of bird nest materials by the nest, species, and urban green area types. Eight nests, excluding a nest abandoned by a pair of Paridae, were used for the material analysis. The collected nests were dried, and classified into natural materials (vegetable materials, animal materials, moss, and soil) and artificial materials (cotton, paper pieces, plastics, vinyl, and synthetic fibers), and then each nest was weighed. The classification result shows that the portion of moss (50.65%) was the highest in all nests, followed by soil (21.43%), artificial material (13.95%), vegetable material (5.78%), animal material (4.57%), and others (3.59%) in that order. Artificial materials were used in all nests in urban green areas. Moreover, although the Paridae used about 5.16% more vegetable material than the Parus varius, it was not significant (t=2.17, p=0.07). Plant materials and soil were most preferred in urban forests, and moss, animal, and artificial materials were widely used in that order in urban parks. There was a significant difference in the use of vegetable materials between urban parks and urban forests (t=3.07, p<0.05^*). In the habitats like urbanized and dry areas, where artificial materials are highly accessible, artificial materials replaced some roles of natural materials. This study is a basic study for the analysis of the types of materials used in artificial bird nests to understand the habitat system of urban ecosystems. It can be used as the basic data for ecological studies and conservation of the Paridae species.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.6 no.3
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• pp.86-96
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• 2003

This study aims to improve system for the enlargement of artificial planting spaces through grasp several problems about it and related system in domestic and foreign. In order to improve system for the extension of artificial planting spaces in the urban area following plans have been presented. First, it is necessary to launch various bonus, subsidies and incentives for making planting spaces in the urban area. Second, subdivision of related regulations for using diverse planting methods is needed. Third, government has to take the initiative in pushing on with planting of artificial spaces. Fourth, it is necessary to development of concrete techniques. Finally, it is desirable to plant artificial spaces which animal and plant can live, low effect to environment and material can be circulated although the value of plantation as a meaning of simple green also are admitted. Planting of artificial spaces should be introduced in a positive light for conservation and restoration of urban ecosystem.

• Journal of Korean Association for Spatial Structures
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• v.7 no.5
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• pp.67-74
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• 2007

The unsymmetrically layered artificial material model is consistently introduced to find the optimum topologies of the plate structures. Reissner-Mindlin (RM) plate theory is adopted to formulate the present 9-node plate element considering the first-order shear deformation of the plates. In the topology optimization process, the strain energy to be minimized is employed as the objective function and the initial volume of structures is adopted as the constraint function. In addition, the resizing algorithm based on the optimality criteria is used to update the hole size introduced in the proposed artificial material model. Several numerical examples are rallied out to investigate the performance of the proposed technique. From numerical results, the proposed topology optimization techniques are found to be very effective to produce the optimum topology of plate structures. In particular, the proposed unsymmetric stiffening layer model make it possible to produce more realistic stiffener design of the plate structures.

• The Korean Journal of Food And Nutrition
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• v.31 no.5
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• pp.631-639
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• 2018

The purpose of this study was to investigate the characteristics of macaroons prepared using natural color materials (Opuntia ficus-indica var. saboten (Re-N), mulberry leaf (Gr-N), pumpkin (Ye-N), and cocoa powder (Br-N)) and corresponding artificial food colorants (red (Re-A), yellow (Ye-A), green (Gr-A) and brown (Br-A)). The moisture content of macaroons prepared using natural color material was higher compared to the macaroons prepared using artificial food colorant. DPPH and ABTS radical scavenging activity was similar in both types of macaroons. Lightness and redness of Re-N, Gr-N, Ye-N, and Br-N macaroons were lower than Re-A, Gr-A, Ye-A and Br-A macaroons. Yellowness of Re-N was higher because of the browning reaction. The texture profile analysis revealed lower hardness when natural color powder was employed. In the sensory evaluation, overall acceptability was not significantly different between natural colored and artificial colored macaroons. As a result, macaroons with the natural color material were softer and showed higher antioxidative activity, however, organoleptic properties were not much different when compared with macaroons with artificial colors. Apparently, it is stated that more studies on the development of macaroons with more enhanced physical functionality and good taste using natural materials should be performed.