• The Journal of the Korea Contents Association
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• v.10 no.4
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• pp.10-18
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• 2010

This paper presents a optimization of sigmoid activation function parameter using genetic algorithms and pattern recognition analysis in input space of two spirals benchmark problem. To experiment, cascade correlation learning algorithm is used. In the first experiment, normal sigmoid activation function is used to analyze the pattern classification in input space of the two spirals problem. In the second experiment, sigmoid activation functions using different fixed values of the parameters are composed of 8 pools. In the third experiment, displacement of the sigmoid function to determine the value of the three parameters is obtained using genetic algorithms. The parameter values applied to the sigmoid activation functions for candidate neurons are used. To evaluate the performance of these algorithms, each step of the training input pattern classification shows the shape of the two spirals.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2009.04a
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• pp.35-39
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• 2009

The equal distribution of the gravity as well as the topographic data is an essential factor in the precision geoid determination. In this study, the area where needs the supplementary gravity survey is assigned through a simulation to build the 5cm level geoid. Based on the current distribution of the gravity data which results in the 8cm level of the precision over all, we extract the area which shows the errors larger than 30 cm. Then, the area is assumed to be filled with gravity data with 2km interval which is turned out to be successfully improving the overall accuracy up to 5cm. Therefore, it is recommended that the supplementary gravity survey should be conducted in mountainous area such as eastern and mid-northern part of Kangwon-Do to achieve the 5cm accuracy on the geoid.

• Journal of Korean Library and Information Science Society
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• v.49 no.2
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• pp.59-78
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• 2018

This study is to suggest the concrete application plan of BIBFRAME under the development of BIBFRAME as library specific ontology for linked open data. The several research methods are used as the literature reviews, the case study of LC and LD4P, and the survey of cataloging librarians which is to grasp understanding level of the linked data related terms and requirements for constructing LOD. The application plan is suggested as follows. First, publishing name authority data and subject heading in LOD are prominent as the startup with creating terms list or vocabulary in LOD that has been used in library for controlled vocabulary and data value. Second, it is needed to develop BIBFRAME application and extension modeling in Korea, to map KORMARC and the properties and classes of BIBFRAME, and to develop the editor and MARC to BIBFRAME Transformation Tools. Third, the systematical training for cataloging librarians is designed to regard BIBFRAME related works as the librarian's main field. Therefore, this study would contribute to seek the practical application plan for BIBFRAME in Korea.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.27 no.2
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• pp.159-167
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• 2009

To obtain the gravity data with consistent quality and good distribution over Korea, to overcome the difficulties in constructing precision geoid from biased distribution of ground data, to resolve the discrepancy between the ground and ocean gravity data, an airborne gravity survey was conducted from Dec. 2008 to Jan. 2009. The data was measured at the average flying height of 3,000m and the data with cross-over error of 2.21mGal is obtained. The geoid constructed using this airborne gravity data shows the range of 9.34 $\sim$ 33.88m. Comparing the geoid with respect to the GPS/levelling data, a precision of 0.145m is obtained. After fitting, the degree of fit to GPS/levelling data was calculated about 5cm. It was found that there exists large biases in the area of south-western and northern part of the peninsular which is considered to be the effect of distorted vertical datum in Korea. Thus, more investigation on vertical datum would be needed in near future.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.20 no.6
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• pp.621-629
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• 2008

Procedures involved in the refinement of the regional geoid for the area encompassing the Korean peninsula and the East Sea are described, and the computational results are provided. A comparison between the geoid height data, the mean sea surface height and the final product of the refinement work is provided and analyzed. The regional marine geoid thus refined seems to have a better resolution, in terms of its correlation with the bathymetry, and shows the bottom features in a more detailed manner when compared with previously used procedures. The general pattern of the computed geoid profile matches reasonably well with the existing studies, where the correlations between the refined regional marine geoid and the bathymetry are (1) 0.44 for the area $117{\sim}142.5^{\circ}E/24{\sim}52^{\circ}N$ and (2) 0.47 for the area $127{\sim}142.5^{\circ}E/32{\sim}50^{\circ}N$ in the East Sea respectively.

• Journal of Creative Information Culture
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• v.6 no.2
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• pp.77-88
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• 2020

The purpose of this study is to statistically analyze the correlation between CS Unplugged education and the computational thinking of gifted and talented students. In this study, qualitative research was conducted for 17 students in 5th grade gifted class at an elementary school in the city of Yongin. Students participated in 10 hours of CS unplugged classes. Student questionnaire, class journals, student activity sheets, and student interview records were collected and qualitatively analyzed. In order to supplement the qualitative data, computational thinking ability tests were also administered. The results of the study are as follows. First, CS unplugged education plays an effective role in improving CT of gifted and talented students. Second, it was not every sub-area of CT that CS unplugged education brought statistically significant improvements in. Third, CS unplugged education is suitable to be presented as the first step of the SW curriculum for gifted and talented students.

• 레미콘
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• no.1 s.74
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• pp.46-55
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• 2003

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.29 no.1
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• pp.81-89
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• 2011

The previous land gravity data in Korea showed locally biased irregular distribution. Especially, this problem was more serious in the mountainous area where the data density was significantly low. The same problem appeared in GPS/Levelling data thus the precision of the geoid could not be improved. From 2008, new gravity and GPS/Levelling data has been collected by the unified control point and survey on the benchmark project which were funded by the national geographic information institute. The newly obtained data has much better distribution and precision so that it could be used for update precision of geoid model. In this study, the new precision geoid has been calculated based old and new gravity data and this model showed 5.29cm of precision compared to 927 points of GPS/Levelling data. And the degree of fit and precision of hybrid geoid has been calculated 2.99cm and 3.67cm. The new gravimetric geoid has been updated about 27% over whole country. And it showed 42% of precision update due to collection of new gravity data on the Kangwon/Kyeongsang area which showed quite low distribution. In 2010, about 4,000 points of gravity and 300 points of GPS/Levelling data has been obtained by unified control and survey on benchmark project. We expect that new data will contribute to updating geoid precision and veri tying precision more objectively.

• Korean Chemical Engineering Research
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• v.48 no.1
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• pp.45-52
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• 2010

Two different imide oligomers(6FDA-ODA/APA and 6FDA-MDA/MA) having crosslinkable end groups were prepared by using a solution imidization method and their properties were investigated. Also, semi-interpenetrating polymer networks(semi-IPN) were prepared using the blends of imide oligomers with polyetherimide $Ultem^{(R)}$, which is used in dual-ovenable packaging materials. The characteristic properties of semi-IPN films were interpreted by using TGA, Thin Film Diffusion Analyzer, and WAXD. Molecular weights of imide oligomers were successfully controlled utilizing 2-aminophenylacetylene(APA) and maleic anhydride(MA) as an endcapping agent. Exotherm reactions by crosslinking appeared and the amount of exthotherm heat was linearly increased as the content of imide oligomers was increased. For semi-IPNs of $Ultem^{(R)}$ and imide oligomers, 5% and 10% weight loss temperatures increased as the contents of imide oligomers were increased. Diffusion coefficient and water uptake of semi-IPNs decreased as the content of imide oligomers was increased, which might be resulted from hydrophobic fluorine group and high packing density. It was concluded that relatively low thermal stability and hydrolytic stability of polyetherimide $Ultem^{(R)}$ were improved by incorporating new developed imide oligomers.

• Journal of the Korea Convergence Society
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• v.9 no.1
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• pp.21-29
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• 2018

The purpose of this study is to explore supporting strategies for teaching and learning based on students' effect recognition and continuous intention in college flipped learning. It was analyzed 426 data by multivariate analysis of variance (MANOVA) by examining student's effect recognition and continuous intention on 15 flipped learning classes of K-university in Chungnam. The characteristics of learners were male, senior students, students who knew flipped learning, students who did not have previous experience, and students who were learning video at anytime. As a teaching strategy, it was found that effect recognition and continuous intention were high in the supplementary deepening flipped learning class and natural science or engineering area. As a teaching and learning supporting strategies, First, the university should develop and operate flipped class learning strategy program for females and low-grade students. Second, it should support the development of good flipped learning design and operation model of instructor. Third, it should support the development of high quality online learning contents that students can learn from time to time. Fourth, it should support the strengthening of teaching competency to develop and operate flipped learning classes. This study can be used as basic data to support and spread the effective flipped learning classes of the university in the future.