• Journal of the Korea Institute of Building Construction
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• v.18 no.3
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• pp.305-312
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• 2018

This study is about the development of a non-sintered binder (NSB) which does not require a sintering process by using the industrial by-products Phosphogypsum (PG), Waste Lime (WL) and Granulated Blast Furnace Slag (GBFS). In this report, through SEM analysis of the NSB paste hardening body, micropore analysis of paste using the mercury press-in method and microstructure observation were executed to consider the influence of the formation of the pore structure and the distribution of pore volume on strength, and the following conclusions were reached. 1) Pore structure of NSB paste of early age is influenced by hydrate generation amount by GBFS and activator. 2) Through observing the internal microstructure of NSB binder paste, it was found that the strength expression at early age due to hydration reaction was achieved with a large amount of ettringite serving as the frame with C-S-H gel generated at the same time. It was confirmed that C-S-H gel wrapped around ettringite, and as time passed, the amount generated continually increased, and C-S-H gel tightly filled the pores of hardened paste, forming a dense network-type web structure. 3) For NSB-type cement, the degree of formation of gel pores below $10{\mu}m$ had a greater influence on strength improvement than simple pore reduction by charging capillary pores, and the pore size that had the greatest effect on strength was micropores with diameter below $10{\mu}m$.

• Korean Journal of Construction Engineering and Management
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• v.24 no.5
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• pp.3-11
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• 2023

Building information modeling (BIM) can help to visualize and manage the building-related information at the object-based level, and it is possible to help link the tasks in the network of Hanok construction. While many studies have significant interest in using BIM for modern construction, there is only few studies to observe the use of BIM for traditional construction, commonly called Hanok construction in South Korea. Hence, the main goal of this study is to develop a system dynamic model for investigating how the BIM can be widely used for Hanok construction. To this end, this study identified the factors influencing the BIM uses for the Hanok construction, developed a causal loop diagram (CLD) to investigate the interrelationships among the factors, and provided a final model based on the mathematical definitions. Based on the scenario analysis, it is demonstrated that the support to building Hanok and education cost for BIM positively influence activating and using the BIM for the Hanok construction. Based on the dynamics of the factors identified in this study, it is important to consider expanding support for Hanok construction and education cost for BIM to successfully integrate and utilize BIM in the construction industry.

• Journal of the Korean BIBLIA Society for library and Information Science
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• v.15 no.2
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• pp.71-96
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• 2004

The purpose of this study is to describe major concepts related to W3C OWL and ISO Topic Maps and to provide the result of comparison and analysis regarding semantic expression power between two ontology languages. This paper is comprised of the following parts: 1) describing URI and namespace concepts that are fundamental building block of effective ontology construction; 2) offering detailed explanation of major Topic Map concepts such as topics, associations, and occurrences; 3) providing how to accomplish the second purpose of cataloging(grouping related items when displaying the search result) using Topic Map; and 4) finally explaining the difference between two ontology languages in terms of semantic expression power.

• Journal of Korean Society of Steel Construction
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• v.27 no.3
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• pp.281-288
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• 2015

Seismic members like damper do not have any treatment of preventing story stiffness reduction after elastic yielding of stories causing story collapse. This paper suggests a method able to prevent story stiffness reduction using high-strength steel. This paper suggests these also : (1) High-strength steel stud column reinforcing story stiffness reduction until story drift 0.02rad can be designed in small area without adjusting layout. (2) Suggested seismic member installing at lowest level shows effects to preventing deformation concentration under huge seismic waves.

• Journal of the Korean Society for Advanced Composite Structures
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• v.3 no.4
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• pp.27-37
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• 2012

The construction of a moment connection for a rectangular hollow section (RHS) column and a H-shaped beam is difficult because the RHS is a closed section. When a inner diaphragm is used for such a connection, in general, it is installed after cutting the HSS columns, which results in increased construction work. This paper suggests a new fabrication method to overcome such problems: An inner diaphragm is welded to inside a C-shaped section first, and then a column is fabricated by welding two C-shaped sections. This fabrication method is superior to a classic method in terms of constructibility. An experimental and a numerical study using Ansys 9.0 were performed in order to compare the strength of connections with respect to the presence of concrete, the corner shape of diaphragm, and the axis of loading. The experimental results including initial stiffness and ultimate loads are reported and the analytical results including load transfer mechanism, degree of stress concentration, and strain distribution are also reported.

• International journal of steel structures
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• v.18 no.4
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• pp.1318-1324
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• 2018

This paper evaluates the effects of door opening, collar stiffener, and initial imperfection on the ultimate strength of a 10 MW wind tower. The lower segment of the tower was modeled to investigate the ultimate strength using steel cylindrical shell elements of finite element program ABAQUS. The wind tower was classified into three categories; without opening nor stiffener (C1), with opening but no stiffener (C2), and with opening and stiffener (C3). The C2 and C3 were further divided into long axis and short axis categories depending on the position of the opening. Result from linear and nonlinear analyses shows that the bigger the opening the bigger the reduction in strength and the same thing goes for the initial imperfection ratio or ovality of the shell. Also, there is a significant decreased in strength as the initial imperfection ratio increases by as high as 18.08%.

• Journal of the Korean Applied Science and Technology
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• v.13 no.3
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• pp.83-94
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• 1996

EMA-co-DAMA were synthesized from 2-diethylaminoethyl metacrylate and ethylhexyl metacrylate in acrylmonomer. To facilitate water emulsification, acrylic copolymer was cationized by acetic acid to produce acetated acrylic copolymer. The structures of the synthesized copolymer and acetated copolymers were confirmed by IR, NMR, and molecular weight was measure by GPC, and C.H.N elemental analysis. Acetated acrylic copolymers were perfectly emulsified in water and showed increased emulsion stability. Polymer dispersion for cement modifier[(PDCM-PED) water proof agent of cement for concrete in building construction] was prepared by blending of the guaternized acrylic copolymer syndisized above, sodium silicate, sodium gluconate and oleic acid emulsion. The result with prepared polymer dispersion of cement modifier was examined, and it was found that excellent waterprooffing effect ; Water permeability ratio is 0.50 under the water pressure of $100g/cm^2$ and 0.60 under $3kg/cm^2$, and water absorption ratio is $0.42{\sim}0.50$ and $1.0{\sim}1.02$ compressive strength ratio at mixed of water/PDCM-PED is 50 times.

• Bulletin of the Korean Chemical Society
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• v.22 no.8
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• pp.857-866
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• 2001

Efficient syntheses of PGI2 analogue 2a and its epimer 3 have been accomplished. Using aryl iodide 6 as the common intermediate, either radical or palladium-assisted tandem alkene insertion strategies have been employed for construction of the benzoprostacyclin framework.

• Microbiology and Biotechnology Letters
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• v.21 no.3
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• pp.214-220
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• 1993

The mating type a of yeast, Saccharomyces cerevisiae mutant with hmla2-102 and sir3-8ts was changed to type alpha by changing the growth temperature from 25C to 35C. A temperature-sensitive expression vector system was constructed using mating factor alpha1 (Mfalpha1) gene encoding alpha factor which is expressed in the type alpha cells. Vectors with different copy numbers were constructed by joining the promoter and pre or prepro-secretion single sequence of Mfalpha1 to promoterless PHO5' gene as a reporter gene.

• Journal of the Korean Recycled Construction Resources Institute
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• v.9 no.1
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• pp.92-99
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• 2021

CaO-based by-products composed of CaO, SO3, Al2O3, etc. are generally used as raw materials for CaO compounds. When applied to the recovered water of ready-mixed concrete, the hydration reaction of the powder material is accelerated and concrete performance can be improved. In this study, activated sludge was prepared to apply to the recovered water of ready-mixed concrete by mixing CaO-based hot-rolled slag(C12A7) in the recycling water of ready-m ixed concrete. Cem ent paste setting time and mortar compressive strength performance tests confirmed the effect on the hydration reaction. Therefore, the possibility of concrete application using activated sludge was confirmed.