• Polymer(Korea)
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• v.36 no.2
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• pp.245-250
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• 2012

Branched polypropylenes (PP) with long chain branch were prepared by solid state reaction with three different branching agent of 0.3 wt% content. The chemical structures, non-isothermal crystallization behavior and complex viscosity of the branched PP were investigated by FTIR, DSC, optical microscope, and dynamic rheological measurement. The chemical structure of the branched PP was confirmed by the existence of =C-H stretching peak of the branching agent at 3100 $cm^{-1}$. There was no distinct change in melting temperature in case of PP-D-0-3 and PP-F-0-3, but PP-H-0-3 indicated a decrease in melting temperature. The decrease in melting temperature was interpreted by the fact that the degradation reaction of PP was more dominant than branched reaction, and confirmed by a decrease in complex viscosity. The non-isothermal crystallization behavior of the branched PP was analyzed using by Avrami equation. The Avrami exponent of PP was 3, and the values of the branched PP with DVB and FS were below 3. The activation energy of PP calculated by Kissinger method was 25 kJ/mol, and there were no big difference in activation energies of the branched PPs compared to PP.

• Polymer(Korea)
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• v.37 no.4
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• pp.494-499
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• 2013

Modified polypropylene (m-PP) was fabricated by furfuryl sulphide (FS) as branching agent and m-PP/nano-filler composites were prepared with silicate and multi-walled carbon nanotube (MWCNT), using a twin screw extruder. The chemical structures and thermal properties of the m-PP were investigated by FTIR and DSC. The chemical structure of the m-PP was confirmed by the existence of =C-H stretching peak of the branching agent at 3100 $cm^{-1}$. There was no district change in melting temperature in case of m-PP, but a certain increase in crystallization temperature was notified and the increase was in the range of $10-20^{\circ}C$. The rheological properties, filler dispersion and foaming behaviors of the m-PP/nano-filler composites were investigated by dynamic rheometer, X-ray diffractometer (XRD) and scanning/transmission electron microscope (SEM/TEM). m-PP/nano-filler composites showed a high complex viscosity at a low frequency, an increase in melt elasticity, and a high shear thinning effect. Compared to pure PP, m-PP and m-PP/nano-filler composites were sufficient to enhance the foaming behavior.

• Korean Journal of Construction Engineering and Management
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• v.15 no.2
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• pp.104-111
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• 2014

Due to the structure of advanced installment sales of houses which is a construction industrial structure unique to Korea and the Project Financing (PF) project structure that includes construction companies' debt guarantee agreements, the changes in accounting methods resulting from the introduction of K-IFRSs are expected to act in a direction to deteriorate construction businesses' financial statements. Therefore, K-IFRSs are an important issue that can seriously affect the entire domestic construction industry and construction businesses are conceiving strategies to respond to the introduction of K-IFRSs. From this viewpoint, this study was intended to empirically analyze the effect of the introduction of K-IFRSs on construction businesses utilizing financial data applied with the K-IFRSs recently announced. In the analysis, the EDFs were calculated by business using the existing accounting standards GAAP and using K-IFRSs and the results were compared with each other. The results of the analysis indicated that most construction businesses were adversely affected by the introduction of K-IFRSs. It is also considered that businesses with relatively good financial statements under the existing accounting standards GAAP would be affected more by the introduction of K-IFRSs than other businesses. In addition, the introduction of K-IFRSs is expected to have larger effects on large construction businesses that have been providing debt guarantees for PF projects than on small or medium sized construction businesses.

• Journal of KIISE:Databases
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• v.36 no.3
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• pp.198-214
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• 2009

Trajectories of RFID tags can be modeled as a line, denoted by tag interval, captured by an RFID reader and indexed in a three-dimensional domain, with the axes being the tag identifier (TID), the location identifier (LID), and the time (TIME). Distribution of tag intervals in the domain space is an important factor for efficient processing of a query for tracing tags and is changed according to arranging coordinates of each domain. Particularly, the arrangement of LIDs in the domain has an effect on the performance of queries retrieving the traces of tags as times goes by because it provides the location information of tags. Therefore, it is necessary to determine the optimal ordering of LIDs in order to perform queries efficiently for retrieving tag intervals from the index. To do this, we propose LID proximity for reordering previously assigned LIDs to new LIDs and define the LID proximity function for storing tag intervals accessed together closely in index nodes when a query is processed. To determine the sequence of LIDs in the domain, we also propose a reordering scheme of LIDs based on LID proximity. Our experiments show that the proposed reordering scheme considerably improves the performance of Queries for tracing tag locations comparing with the previous method of assigning LIDs.

• Education of Primary School Mathematics
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• v.16 no.1
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• pp.57-70
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• 2013

This study is aimed to compare the area of geometry of elementary mathematics textbooks in korea and china. Through this study, we would like to suggest some guidelines in order to develop geometric curriculum and textbooks in korea and to search for more efficient methods of learning mathematics. For this, we have looked through the general characteristics of geometry domain in mathematics curriculums and the textbooks in korea and china. Furthermore, we have found the similarities and differences while comparing specific contents in the two countries. The followings are the conclusions of this study. First, The mathematics curriculum in korea is divided into 'figure' domain, but the one in china is divided into 'space and figure' domain, which deals with figure and measurement. And china constructs the contents of the basic figure as a whole unit. Second, korea gives clear learning aims about contents whereas china gives learning activities. Lastly, when starting teaching a plain figure, korea focuses on checking and finding definitions and characters through fundamental figures. However, china focuses on figuring out components and the relations among them throughout various plain figure activities.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.33 no.4
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• pp.325-331
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• 2015

This paper suggests an intersection method to improve the accuracy of three-dimensional position from heterogeneous satellite stereo images, and addresses validation of the suggested method following the experimental results. The three-dimensional position is achieved by determining an intersection point of two rays that have been precisely adjusted through the sensor orientation. In case of conventional homogeneous satellite stereo images, the intersection point is generally determined as a mid-point of the shortest line that links two rays in at least square fashion. In this paper, a refined method, which determines the intersection point upon the ray adjusted at the higher resolution image, was used to improve the positioning accuracy of heterogeneous satellite images. Those heterogeneous satellite stereo pairs were constituted using two KOMPSAT-2 and QuickBird images of covering the same area. Also, the positioning results were visually compared in between the conventional intersection and the refined intersection, while the quantitative analysis was performed. The results demonstrated that the potential of refined intersection improved the positioning accuracy of heterogeneous satellite stereo pairs; especially, with a weak geometry of the heterogeneous satellite stereo, the greater effects on the accuracy improvement.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.10
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• pp.635-646
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• 2016

This paper proposes a housing business model, where the presale and Chonsei housing are supplied under a presale system at the same time based on the characteristic correlation between the housing presale market and Chonsei market in Korea. Markowitz portfolio theory was used to review the risk diversification effects from the changes in the ratio between the presale housing supply and the Chonsei housing supply. The housing sale price indicator was used as a proxy variable to determine the presale housing supply. The housing Chonsei price indicator was used as a proxy variable to determine the Chonsei housing supply. The proposed housing business model was applied to major areas in Korea to examine the risk diversification effect. Comparisons of the regional portfolio analyses showed that the flexibility of the proposed housing business model can be quite effective because each regional housing market exhibits different characteristics. Market participants, such as developers, construction companies, consumers, and government, can expect various effects through the proposed housing business model. Nevertheless, policy support is necessary for practical applications of the proposed housing business model. In particular, public funds from the government need to be introduced.

• Korean Journal of Heritage: History & Science
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• v.45 no.3
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• pp.212-223
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• 2012

Pigments used paintings, ornaments, weapons and various objects have been recognised as important elements to ascertain the history, manufacturing technique and cultural migration. Since the understanding of composition of pigments by analysis began in 1963, its technique and methodology has much advanced in recent years; recent study used the portable X-ray Fluorescence as non-destructive analysis has been practiced in particular. However the study on pigments necessitates overall and systematic research because it is difficult to understand periodical and regional use of pigments. by fractional studies. Therefore this research investigates the coloring materials and painting techniques of the scroll painting depicting preaching scene of Sakyamuni Buddha in Daeungjeon Hall, a main hall of Bulguk temple, through scientific analysis and comparison of various pigments which had been applied to the buddhist paintings of Joseon Dynasty. Consequently, it is confirmed that the scroll painting used pigments of white lead[$2PbCO_3{\cdot}Pb(OH)_2$] for ground layer and used mixture of different pigments such as cinnabar (HgS) minium($Pb_3O_4$) malachite($2CuO{\cdot}CO_2{\cdot}H_2O$) hematite($Fe_2O_3$) gold(Ag) for presenting various colors on the painting layer. It has been also believed that mineral pigments were applied to the scroll painting, yet it is difficult to confirm whether it is natural or synthetic pigments because the crystal structures of pigments were not analyzed. The results of this study, however, provide useful reference data for the understanding of the components of pigments and manufacturing techniques of buddhist scroll paintings, in particular, of Joseon Dynasty.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.17 no.3
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• pp.321-328
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• 2019

The detection performances of the NaI(Tl), $LaBr_3$(Ce) and $CeBr_3$ scintillation detectors, which can be used to rapidly evaluate the major artificial radionuclides deposited on the soil surface in a nuclear accident or radiological emergency, were compared. Detection performance was assessed by calculating the minimum detectable activity (MDA). The detection efficiency of each detector for artificial radionuclides was semi-empirically determined using mathematical modelling and point-like sources having certified radioactivity. The background gamma-ray energy spectrum for MDA evaluation was obtained from relatively wide and flat grassland, and the MDA values of each detector for the major artificial radionuclides that could be released in nuclear accidents were calculated. As a result, the relative MDA values of each detector regarding surface deposition distribution at normal environmental radiation level were evaluated as high in the order of the NaI(Tl), $LaBr_3$(Ce), and $CeBr_3$ detectors. These results were compared based on each detector's intrinsic and measurement environment background, detection efficiency, and energy resolution for the gamma-ray energy region of the radionuclide of interest.

• Journal of The Korean Society of Grassland and Forage Science
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• v.40 no.4
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• pp.259-264
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• 2020

The aim of this study was to investigate the feasibility of discrimination 12 different cultivar of sorghum × sudangrass hybrid (Sorghum genus) seed through near infrared spectroscopy (NIRS). The amount of samples for develop to the best discriminant equation was 360. Whole samples were applied different three spectra range (visible, NIR and full range) within 680-2500 nm wavelength and the spectrastar 2500 Near near infrared was used to measure spectra. The calibration equation for discriminant analysis was developed partial least square (PLS) regression and discrimination equation (DE) analysis. The PLS discriminant analysis model for three spectra range developed with mathematic pretreatment 1,8,8,1 successfully discriminated 12 different sorghum genus. External validation indicated that all samples were discriminated correctly. The whole discriminant accuracy shown 82 ~ 100 % in NIR full range spectra. The results demonstrated the usefulness of NIRS combined with chemometrics as a rapid method for discrimination of sorghum × sudangrass hybrid cultivar through seed.