• Korean Journal of Remote Sensing
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• v.36 no.5_2
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• pp.989-1006
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• 2020

Building change monitoring based on building detection is one of the most important fields in terms of monitoring artificial structures using high-resolution multi-temporal images such as CAS500-1 and 2, which are scheduled to be launched. However, not only the various shapes and sizes of buildings located on the surface of the Earth, but also the shadows or trees around them make it difficult to detect the buildings accurately. Also, a large number of misdetection are caused by relief displacement according to the azimuth and elevation angles of the platform. In this study, object-based building detection was performed using the azimuth angle of the Sun and the corresponding main direction of shadows to improve the results of building change detection. After that, the platform's azimuth and elevation angles were used to detect changed buildings. The object-based segmentation was performed on a high-resolution imagery, and then shadow objects were classified through the shadow intensity, and feature information such as rectangular fit, Gray-Level Co-occurrence Matrix (GLCM) homogeneity and area of each object were calculated for building candidate detection. Then, the final buildings were detected using the direction and distance relationship between the center of building candidate object and its shadow according to the azimuth angle of the Sun. A total of three methods were proposed for the building change detection between building objects detected in each image: simple overlay between objects, comparison of the object sizes according to the elevation angle of the platform, and consideration of direction between objects according to the azimuth angle of the platform. In this study, residential area was selected as study area using high-resolution imagery acquired from KOMPSAT-3 and Unmanned Aerial Vehicle (UAV). Experimental results have shown that F1-scores of building detection results detected using feature information were 0.488 and 0.696 respectively in KOMPSAT-3 image and UAV image, whereas F1-scores of building detection results considering shadows were 0.876 and 0.867, respectively, indicating that the accuracy of building detection method considering shadows is higher. Also among the three proposed building change detection methods, the F1-score of the consideration of direction between objects according to the azimuth angles was the highest at 0.891.

• Journal of Korea Entertainment Industry Association
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• v.14 no.3
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• pp.27-40
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• 2020

The marathon has long been established as a representative lifestyle for all ages. With the recent expansion of the Work and Life Balance trend across the society, marathon with a relatively low barrier to entry is gaining popularity among young people in their 20s and 30s. By analyzing the issues and related words of the marathon event, we will analyze the spottainment elements of the marathon event that is popular among young people through keywords, and suggest a development plan for the differentiated event. In order to analyze keywords and related words, blogs, cafes and news provided by Naver and Daum were selected as analysis channels, and 'JTBC Marathon' and 'Culture' were extracted as key words for data search. The data analysis period was limited to a three-month period from August 13, 2019 to November 13, 2019, when the application for participation in the 2019 JTBC Marathon was started. For data collection and analysis, frequency and matrix data were extracted through social matrix program Textom. In addition, the degree of the relationship was quantified by analyzing the connection structure and the centrality of the degree of connection between the words. Although the marathon is a personal movement, young people share a common denominator of "running" and form a new cultural group called "running crew" with other young people. Through this, it was found that a marathon competition culture was formed as a festival venue where people could train together, participate together, and escape from the image of a marathon run alone and fight with themselves.

• Proceedings of the Technology Innovation Conference
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• 1996.12a
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• pp.265-295
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• 1996

This paper investigates empirically the relationship between various business portfolio properties (particularly technological properties) and chaebol′s performance using data on the 50 largest chaebols in Korea. In addition to the traditional indexes to measure diversification such as entropy index we calculated inter-industry technological similarity using R&D expenditure data by industry and 1990 Input-output Table in Korea, and obtained chaebol-level technological relatedness and internal transaction proportion from chaebols′business profile, inter-industry technological similarity and 1990 input-output table. We applied factor analysis on 13 business portfolio property indexes and showed that they could be grouped into 3 dimensions, diversification scope, inter-business relatedness and degree of vertical integration. In this paper, using 50 largest chaebols′financial data (1989-1994), we analyzed empirically the effect of business portfolio properties on ROS (Return On Sales) which is conventional index for firm performance and on TFP(Total Factor Productivity) growth which is a pure measure of firm performance. To utilize the advantage of panel data, FEM(Fixed Effect Model) and REM(Random Effect Model) were used. The empirical result shows that the entropy index as a measurement of inter-business relatedness is not significant but technological relatedness index is significant. OLS estimates on pooled data were considerably different from FEM or REM estimates on panel data. By introducing interaction effect among the three variables for business portfolio properties, we obtained three findings. First, only VI (Vertical integration) has a significant positive correlation with ROS. Second, when using TFP growth as an dependent variable, both TR(Technological Relatedness) and f[ are significant and positively related to the deepened variable. Third, the interaction term between TR and VI is significant and negatively affects TFP growth, meaning that TR and VI are substitutes. These results suggest strategic directions on restructuring business portfolio. As VI is increased, chaebols will get more profit. A higher level of either TR or W will increase TFP growth rate. but increase in both TR and VI will have a negative effect on TFP growth. To summarize, certain business portfolio properties such as VI and TR can be considered "resources" themselves since they can affect profit rate and productivity growth. VI and TR have a synergy effect of change in profit rate and productivity growth. VI increases ROS and productivity growth, while TR increases productivity growth representing a technological synergy effect.

• Korean Journal of Materials Research
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• v.1 no.3
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• pp.115-124
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• 1991

In this study, the relationship between mechanical properties and the effects of second phase in tri-phase steel which was composed of ferrite-martensite-bainite was investigated. In order to obtain different microstructure of ferrite+martensite(DP), ferrite+bainite(F+B), and ferrite+martensite+bainite(TP, different heat treatment has been accomplished. The effects of volume fraction and microstructure of each specimen were studied on tensile property, Charpy impact energy and stretch-flangeability. As the bainite content in triphase steels increased, the tensile strength, and yield strength decreased as well as the reduction of area and strength-uniform elongation increased. However, ferrite-bainite steel had high yield ratio and yield point elongation. The Charpy impact energy of TP and F+B steel was higher than that of DP steel. In addition, the characteristics of hole expanding limit($\lambda$) of TP steel and F+B steel were higher than that of DP steel. These mechanical properties of tri-phase steel have been improved, because bainite could be deformed easily within ferrite matrix. The effect of bainite on ductility in tri-phase steel has been found to be favorable. In this experiment, tri-phase steel contained within 27% bainite volume fraction had good nechanical properties and superior stretch-flangeability.

• Journal of the Korean Society for Nondestructive Testing
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• v.18 no.3
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• pp.172-180
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• 1998

It is attempted to verify the Quantitative relationship between fracture mechanical parameters (${\Delta}K$, $K_{max}$) and X-ray parameters (residual stress, half-value breadth) of A12009-15v/o $SiC_w$ composite, and normalized SS41 steel. In this study, fatigue crack propagation test were carried out and X-ray diffraction was applied to fatigue fractured surface in order to investigate the change of residual stress and half-value breadth on fatigue fractured surface. And it is loaded prestrain to each tensile specimen, A12009-15v/o $SiC_w$ composite(0.3, 0.5, 1, 1.5, 2%) and normalized SS41 steel(0.63, 2.25, 7.50, 13.7, 20%), for investigating plastic strain rate using nondestructive measurement method. X-ray diffraction was applied to the prestrained tensile specimens in order to measure the change of residual stress and half-value breadth.

• Asian-Australasian Journal of Animal Sciences
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• v.25 no.9
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• pp.1205-1215
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• 2012

This study was conducted to establish genetic criteria for phenotypic characteristics of Hanwoo cattle based on allele frequencies and genetic variance analysis using microsatellite markers. Analysis of the genetic diversity among 399 Hanwoo cattle classified according to nose pigmentation and coat color was carried out using 22 microsatellite markers. The results revealed that the INRA035 locus was associated with the highest $F_{is}$ (0.536). Given that the $F_{is}$ value for the Hanwoo INRA035 population ranged from 0.533 (white) to 1.000 (white spotted), this finding was consistent with the loci being fixed in Hanwoo cattle. Expected heterozygosities of the Hanwoo groups classified by coat colors and degree of nose pigmentation ranged from $0.689{\pm}0.023$ (Holstein) to $0.743{\pm}0.021$ (nose pigmentation level of d). Normal Hanwoo and animals with a mixed white coat showed the closest relationship because the lowest $D_A$ value was observed between these groups. However, a pair-wise differentiation test of $F_{st}$ showed no significant difference among the Hanwoo groups classified by coat color and degree of nose pigmentation (p<0.01). Moreover, results of the neighbor-joining tree based on a $D_A$ genetic distance matrix within 399 Hanwoo individuals and principal component analyses confirmed that different groups of cattle with mixed coat color and nose pigmentation formed other specific groups representing Hanwoo genetic and phenotypic characteristics. The results of this study support a relaxation of policies regulating bull selection or animal registration in an effort to minimize financial loss, and could provide basic information that can be used for establishing criteria to classify Hanwoo phenotypes.

• The Korean Journal of Applied Statistics
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• v.29 no.7
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• pp.1201-1212
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• 2016

Value at Risk (VaR) for market risk management is a favorite method used by financial companies; however, there are some problems that cannot be explained for the amount of loss when a specific investment fails. Conditional Tail Expectation (CTE) is an alternative risk measure defined as the conditional expectation exceeded VaR. Multivariate loss rates are transformed into a univariate distribution in real financial markets in order to obtain CTE for some portfolio as well as to estimate CTE. We propose multivariate CTEs using multivariate quantile vectors. A relationship among multivariate CTEs is also derived by extending univariate CTEs. Multivariate CTEs are obtained from bivariate and trivariate normal distributions; in addition, relationships among multivariate CTEs are also explored. We then discuss the extensibility to high dimension as well as illustrate some examples. Multivariate CTEs (using variance-covariance matrix and multivariate quantile vector) are found to have smaller values than CTEs transformed to univariate. Therefore, it can be concluded that the proposed multivariate CTEs provides smaller estimates that represent less risk than others and that a drastic investment using this CTE is also possible when a diversified investment strategy includes many companies in a portfolio.

• Journal of The Korean Association For Science Education
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• v.34 no.5
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• pp.491-497
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• 2014

The purpose of this study is to investigate the structural relationships among the attitude toward science and science motivation such as affective characteristics, and self-regulated learning strategy such as cognitive factor of science achievement. 853 middle school students residing in Seoul completed questionnaires about attitude toward science, science motivation, and self-regulated learning strategy. The sample variance-covariance matrix was analysed using AMOS 20.0, and a maximum likelihood minimization function. The results are as follows: First, attitude toward science, science motivation and self-regulated learning strategy of middle school students were all found to have a significant direct effect on science achievement. Second, attitude toward science and science motivation in middle school students has a direct effect on the self-regulated learning strategy. Third, attitude toward science in middle school students has a substantial indirect effect on science achievement mediated by their self-regulated learning strategy. Forth, science motivation in middle school students has indirect effect on science achievement mediated by their self-regulated learning strategy. Therefore, in order to improve science achievement among middle school students, teachers should consider synthetically the affective characteristics such as attitude toward science and science motivation, and cognitive factor such as self-regulated learning strategy.

• Investigative Magnetic Resonance Imaging
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• v.11 no.2
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• pp.110-118
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• 2007

Purpose: The objective of this work to construct eigenvalue maps that have information of magnitude of three primary diffusion directions using diffusion tensor images. Materials and Methods: To construct eigenvalue maps, we used a 3.0T MRI scanner. We also compared the Moore-Penrose pseudo-inverse matrix method and the SVD (single value decomposition) method to calculate magnitude of three primary diffusion directions. Eigenvalue maps were constructed by calculating of magnitude of three primary diffusion directions. We did investigate the relationship between eigenvalue maps and fractional anisotropy map. Results: Using Diffusion Tensor Images by diffusion tensor imaging sequence, we did construct eigenvalue maps of three primary diffusion directions. Comparison between eigenvalue maps and Fractional Anisotropy map shows what is difference of Fractional Anisotropy value in brain anatomy. Furthermore, through the simulation of variable eigenvalues, we confirmed changes of Fractional Anisotropy values by variable eigenvalues. And Fractional anisotropy was not determined by magnitude of each primary diffusion direction, but it was determined by combination of each primary diffusion direction. Conclusion: By construction of eigenvalue maps, we can confirm what is the reason of fractional anisotropy variation by measurement the magnitude of three primary diffusion directions on lesion of brain white matter, using eigenvalue maps and fractional anisotropy map.

• Journal of Internet Computing and Services
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• v.18 no.3
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• pp.19-28
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• 2017

Collaborative filtering (CF) is a system that interprets the relationship between a user and a product and recommends the product to a specific user. The CF model is advantageous in that it can recommend products to users with only rating data without any additional information such as contents. However, there are many cases where a user does not give a rating even after consuming the product as well as consuming only a small portion of the total product. This means that the number of ratings observed is very small and the user rating matrix is very sparse. The sparsity of this rating data poses a problem in raising CF performance. In this paper, we concentrate on raising the performance of latent factor model (especially SVD). We propose a new model that includes product similarity information and co occurrence information in SVD. The similarity and concurrence information obtained from the rating data increased the expressiveness of the latent space in terms of latent factors. Thus, Recall increased by 16% and Precision and NDCG increased by 8% and 7%, respectively. The proposed method of the paper will show better performance than the existing method when combined with other recommender systems in the future.