• Journal of Digital Convergence
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• v.17 no.12
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• pp.1-11
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• 2019

The purpose of this study is to investigate factors influencing educational performance and mediating effects of learning presence in the university flipped learning classroom. For achieving this purpose, self-regulation, learning presence, and collaborative preference were selected as learner variables, and perceived academic achievement and learning engagement were selected as variables for educational performance. To investigate causal relationships among the variables, 39 university students who took 16 week course flipped-learning class participated self-reported survey. Collected data were analyzed by multiple regression and mediation analyses. The results were as follows: first, learning presence and self-regulation affected learning engagement, and moreover, the learning presence mediated between self-regulation and learning engagement. Second, only learning presence affected perceived academic achievement. Therefore, various strategies for effective flipped learning should be considered, and well-designed classroom activities that can promote learners self-regulation, learning presence, and learning engagement are needed to successful flipped learning.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.18 no.2
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• pp.129-134
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• 2000

To utilize the survey method using the geodetic satellite GPS, we tried to analysis the GPS/Leveling and the geopotential model of the 26 GPS observation points including 23 BM and 3 triangulation points with approximately 16-km interval selected from the Andong geographic map with a scale of 1:250,000. The average deviations of the geopotential model calculated from the results of analysis to the GPS/Leveling and the previously developed geopotential models(EGM96, OSU91A, and KGEOID), are 0.493 m, 0.277 m, and 0.195 m, respectively and RMS errors are $\pm$0.299 m, $\pm$0.152 m, and $\pm$ 0.133 m. The general trend of geoid undulations, however, shows an increasing pattern to the NW-SE direction. It has been also reported that the geoid undulation related with topographic-highs and geoid-highs although very poor relationship is shown in this area.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.27 no.2
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• pp.213-223
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• 2009

In geoid modelling field, it is very important the GPS/leveling data because it could be check-out the accuracy of gravimetric geoid and computed the hybrid geoid. In this study, GPS surveying was accomplished in the test area including mountainous area to improve the GPS/leveling data density in Korea. And the geometric geoidal heights was calculated using the GPS/leveling data in the test area and the accuracy of the geoidal heights was analyzed. For this study, GPS surveying was accomplished on the 211 1st and 2nd order benchmarks in Gyeongbuk province and 198 GPS/leveling data were achieved after both baseline analysis and network adjustment. Geometric geoidal heights were calculated using these 198 GPS/leveling data and the accuracy analysis was done by comparison with the geoidal heights from EGM2008 geopotential model. The results showed that the bias and standard deviation computed from 190 GPS/leveling data after gross removal was -0.185$\pm$0.079m. And also, the accuracy analyses according to the benchmark order, baseline length, and altitude were accomplished.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.7
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• pp.2522-2527
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• 2010

The aim of this study was to investigate the tyrosinase inhibitory activity and antimicrobial activity by mixtures of ultrasonicated chitosan and Maillard reaction products. Analysis of tyrosinase was purified from potato and confirmed by active staining after SDS-PAGE. Maillard reaction products (MRPs) were formed from various sugars (glucose, fructose, galactose, xylose, arabinose or ribose) and cystein. MRPs inhibited the tyrosinase purified from potato. The highest tyrosinase inhibitory activity was shown by MRP from glucose and cystein. Ultrasonicated chitosan (over 1 hr) showed antimicrobial activity at the concentration of 1% against E. coli and S. aureus. For the development of antibrowning agent with antimicrobial activity, tyrosinase inhibitory and antimicrobial activity by the mixtures of ultrasonicated chitosan and MRP were tested. 1:1 mixture of ultrasonicated chitosan and MRP from glucose and cystein was the best antibrowning agent having antimicrobial activity.

• Resources Recycling
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• v.10 no.4
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• pp.42-47
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• 2001

Recycling of aluminum dross is a significant issue in domestic aluminum industry. In this study, formed ceramic materials were prepared using aluminum dross mixed with feldspar powders to investigate its application as industrial materials and utilization of aluminum dross. In the prepared sample, feldspar was melted at the sintered temperature, and its phase was trans-formed into amorphous, and spinel ($MgA1_2$$O_4$) phase in the dross was remained clearly. Density of the test specimen Increased from 0.91 to 0.65 gr/㎤ and water absorbance decreased from 2.5 to 1.7f% with increasing of sintered time at the sintered temperature $1220^{\circ}C$ with composition of feldspar 55 wt%, dross 40wt% and bentonite 5 wt%. At the same experimental conditions, bending strength of the test specimen was 10.8 MPa, and heat conductivity was 0.34 W/m.K with sintered time 30 minutes.

• Polymer(Korea)
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• v.28 no.4
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• pp.335-343
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• 2004

Carmustine (l,3-bis(2-chloroethyI)-1-nitrosourea, BICNU) used as antineoplastic drug for the treatment of brain tumor is not appropriate for the long term delivery, because it has short biological half life. Therefore, poly(D,L-lactide-co-glycolide) (PLGA) is useful as drug carrier for the long term delivery due to bulk erosion property. Glycolide monomer is applied to release of BICNU owing to non-toxic and monomeric components after biodegradation of PLGA. In this study, BICNU-loaded PLGA wafers with or without glycolide monomer were fabricated by conventional direct compression method for the sustained release of BICNU. These wafers were observed for their release profiles of BICNU and degradation rates by SEM, NMR, and GPC. Furthermore, we make multi-layer wafers and compare them with release profiles of conventional wafer. From these results, drug release of BICNU-loaded PLGA wafers was increased with increasing the glycolid monomer contents. We confirmed that glycolide monomer and BICNU contents in barrier-layer influenced the drug release profiles and degradation rate.

• Journal of KIISE:Computer Systems and Theory
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• v.36 no.1
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• pp.1-8
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• 2009

Oligonucleotide design is known as a time-consuming work in Bioinformatics. In order to accelerate the oligonucleotide design process, one of the most widely used approaches is the prescreening unreliable regions using hashing(or seeding) method represented by BLAST. Since the seeding is originally proposed to increase the sensitivity for local alignment, the specificity should be considered as well as the sensitivity for the oligonucleotide design problem. However, a measure of evaluating the seeds regarding how adequate and efficient they are in the oligo design is not yet proposed. we propose a novel measure of evaluating the seeding algorithms based on the discriminability and the efficiency. By the proposed measure, five well-known seeding algorithms are examined. The spaced seed is recorded as the best efficient discriminative seed for oligo design.

• Journal of The Korean Association of Information Education
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• v.23 no.5
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• pp.441-449
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• 2019

With the introduction of the 2015 revised curriculum, software education became mandatory in elementary school. The practical subject in the content for the software education consists of information ethics, algorithms, programming, and computer science. Especially, elementary school encourages the unplugged activities. Unplugged activities are preferred among the teachers in the education field as a teaching-learning method. However, those teachers pointed out that the lack of suitable unplugged activity materials was the biggest challenge. In addition, it was pointed out that the existing materials were not suitable for achievement standards, and there are many simple playing-oriented educations that are not linked to computing activities. In this study, we developed an unplugged activity-oriented robot that can be used for the elementary students to learn the basic control structure suggested in the achievement criteria SW education and to develop creative problem solving ability through various activities using sensors. The effectiveness was verified through the software class using the developed robot in this study.

• Knowledge Management Research
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• v.22 no.3
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• pp.17-29
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• 2021

The purpose of this study is to analyze investment performance by applying dynamic methodologies that reflect market expectations rather than traditional static methodologies in applying the glide path of target date fund. In calculating market expectations, the number of distributed shares in the ETF market was used, and the dynamic glide path model portfolio considering market expectations in the analysis period from late 2011 to October 2020 could show better results than the existing static glide path. According to the analysis, increasing the portion of risky assets at a time when the number of shares in the ETF's distribution increases, and in the opposite case, reducing the portion of risky assets is advantageous for profit. The results of this study are expected to provide useful theoretical and practical implications for researchers and asset management workers who are interested in knowledge management from a broad perspective beyond the boundary of pension asset management to the public fund market and ETF market.

• Journal of The Korean Association of Information Education
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• v.23 no.1
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• pp.19-27
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• 2019

This study analyzed the effect of an unplugged educational program which focuses on the algorithm execution time analysis on enhancing the computational thinking of the third grade students. An unplugged educational program was developed by following the procedures of the ADDIE model based on the result of the demand analysis conducted with 70 incumbent elementary school teachers and 120 third grade students. The developed program was applied to 24 third grade students for 36 classes in six days and a comparison was made through pre-post comparison tests with 24 students who were taught with a board game program for the same period of time. As a result, the unplugged education program which focuses on the algorithm execution time analysis is deemed to have positive effect on the computational thinking of the third grade students.