• Journal of Intelligence and Information Systems
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• v.14 no.3
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• pp.133-154
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• 2008

The data imbalance problem which can be uncounted in data mining classification problems typically means that there are more or less instances in a class than those in other classes. In order to solve the data imbalance problem, there has been proposed a number of techniques based on re-sampling with replacement, adjusting decision thresholds, and adjusting the cost of the different classes. In this paper, we study the feasibility of the combination usage of the techniques previously proposed to deal with the data imbalance problem, and suggest a combination method using genetic algorithm to find the optimal combination ratio of the techniques. To improve the prediction accuracy of a minority class, we determine the combination ratio based on the F-value of the minority class as the fitness function of genetic algorithm. To compare the performance with those of single techniques and the matrix-style combination of random percentage, we performed experiments using four public datasets which has been generally used to compare the performance of methods for the data imbalance problem. From the results of experiments, we can find the usefulness of the proposed method.

• Journal of Digital Convergence
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• v.13 no.9
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• pp.169-175
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• 2015

The significant changes of convergence study in the 21st century is the shift from theoretical-based instruction to computer-based instruction. This study investigated the student's cognitive engagement in TPB(Theory of Planned Behavior) of accounting information classes in the Digital Convergence Era. Hypothesis test was conducted from 99 accounting information learners from four year course university in the Gyeonggi-do. A questionnaire was given and analyzed. The results showed. First, the TPB variables han a positive effect on intrinsic curiosity of students. Second, the subjective norm of TPB variables could develop student's enjoyment. Subject norm could have a positive effect on enjoyment. The results of this study may contribute to propose desirable ways of improving the psychological states in the relationship between TPB and cognitive engagement. In the future, variables of cognitive engagement will be compliment to analyze.

• Journal of Korean Academy of Nursing
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• v.48 no.2
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• pp.232-240
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• 2018

Purpose: The aim of this study is to identify the types of gambling among adolescents and provide basic prevention information regarding adolescents' gambling problems. Methods: Secondary data from representative national survey on 2015 Youth Gambling Problems of Korea Center on Gambling Problems were used. Using latent class analysis (LCA), 13 gambling types such as offline and online games of 14,011 adolescents were classified, and gambling experiences and characteristics were analyzed. Results: The subgroups of adolescent gambling were identified as four latent classes: a rare group (84.5% of the sample), a risk group (1.0%), an offline group (11.9%), and an expanded group (2.6%). The types and characteristics of gambling among the latent classes differed. In the risk group, adolescents participated in online illegal sports betting and internet casino, and gambling time, gambling expenses, and the number of gambling types were higher than other groups. Conclusion: Gambling frequently occur among adolescent, and the subtypes of gambling did not reveal homogeneous characteristics. In order to prevent adolescent gambling problems, it is a necessary to develop tailored prevention intervention in the nursing field, which is appropriate to the characteristics of adolescent gambling group and can help with early identification.

• Korean Journal of Health Education and Promotion
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• v.22 no.3
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• pp.65-81
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• 2005

Objectives: This study was conducted to describe child perceived health knowledge, health education needs, and health behaviors by sex as a representative general characteristic and examined their associations for students' better health behavior changes. Methods: The survey participants were 410 fourth to sixth grade students in two elementary schools in Seoul, Korea. A total of 12 classes in two elementary schools were randomly selected and all students of the selected classes participated in the self-administered survey. The questionnaire contained the items of perceived health knowledge, health education needs (health topics which they want to know more), health behavior, and general characteristics. Results: Perceived health knowledge, health education needs, and health behaviors were, generally, better among girls than boys. Sexual differences were not large in perceived health knowledge, health education needs, health behaviors. Perceived health knowledge had significant positive correlation with health behaviors both in boys and girls(p <.01). The correlation between perceived health knowledge and health behaviors(r =.36) was two fold greater than correlation between health education needs and health behaviors(r =.18) among boys; where as the two correlations were similar to each other among girls. The significant factors were perceived health knowledge, sex, grade, and health education needs in order, and the four factors described health behaviors in 21.0%. The higher perceived health knowledge, girls, lower grade, and more health education needs was associated with the better health behaviors. Conclusions: There was significant sexual difference of the relationship between health knowledge, health education needs, and health behaviors among children. Perceived health knowledge was more important factor to improve health behaviors among boys while perceived health knowledge and health education needs had equal importance on health behaviors among girls. Therefore, knowledge building should be an essential part of health education class goals for building better health behaviors.

• Journal of Korean Elementary Science Education
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• v.39 no.1
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• pp.54-68
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• 2020

The purpose of this study is to investigate how elementary teachers perceive and practice using Visual Thinking (VT) in science classes. For this, we collected 161 VT teaching materials for science that uploaded on the elementary teacher's online communities, and analyzed the characteristics. Also we interviewed four elementary teachers who have used VT in science class. The results are as follows. First, VT teaching materials shared in teacher's online communities were most often used to review the science concepts that students learned. Most of the materials required 'remember' among the Cognitive Process, and most of them provided layouts for VT activities. Second, the participants were using VT materials to review the science concepts they learned, so that students remember them. Third, the participants were satisfied because of the beliefs of effects as follows: facilitating learning and reviewing what students had learned; increasing students' positive reactions and confidence; learning through the interation among learners; the formation of habits thinking visually; indirect experiences of science class; possibility of class corresponding to learner characteristics. Fourth, the participants had difficulties in preparing for the VT science class, such as the burden of making VT materials, the long preparation time, concerns over overlapping contents, consideration of learners' VT skills, and the themselves' drawing ability. Furthermore, they also had difficulties in proceeding for the class, like different preference among learners about Visualization and loss of objectives in science class using VT. Fifth, the participants needed support as follows: platform to share students' VT results; VT case books and teachers' guidebooks; physical environment.

• Journal of the Korean Institute of Educational Facilities
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• v.16 no.6
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• pp.3-12
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• 2009

Reports on population movement(2000-2030) by the National Statistical Office show that the number of elementary school age population will be decreased by 1.4million from 2005 to 2020. It will effect both school size and the policies for school facilities, which have focused on downsizing class as the high standard of OECD nations. As the unfolding evidence is emerging that a number of schools and classes will be emptied out by 2030. This study aims at developing a objective and scientific device for estimate the number of students at future and evaluating the validity of school establishment. In doing so, it explores the relationship between the changing factors and the number of students. It proposes four factors such as the changes of population, the fertility rate, the number of apartment occupant and movement of population. As the result of the statistic analysis on the correlation coefficient, it finds out that the change of apartment occupant has a close correlation with the change in the number of student and has a deep effect on the establishment of school. Finally, it shows the construction of school according to urban developments during 1999-2008 in Incheon Metro-City. This study would help the authorities to expect the future number of student and to restrict overbuilding of surplus classes, finally the reasonable expenditure for school facilities.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.24 no.8B
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• pp.1480-1489
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• 1999

In this paper, we propose a new post-processing method which can solve a problem of MSDS(Mean Squared Difference of Slope) method. Using that method the blocking artifacts can significantly be reduced without any restriction, which is a major drawback of block-based DCT compression method. In this approach, the OSLD(Overlapped Sub-Laplacian Distribution) of dequantized block boundary pixel difference values is defined and used to categorize each block of an image into one of four types. Those types are also classified into one of two classes: an edge and a non-edge classes. A slope across the block boundary is used to quantify discontinuity of the image. If an absolute estimated quantization error value of a DCT coefficient is greater than the corresponding quantization step size, it is saturated to the step size in the edge class. The proposed post-processing method can improve not only the PSNR value up to 0.1~O.3 dB but visual quality without any constraints determined by ad-hoc manner.

• Journal of the Korea Society of Computer and Information
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• v.11 no.3
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• pp.281-289
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• 2006

Even though software developing environment has been changing to Web basis very fast, there are just few studies of quality metric or estimation model for Web software. In this study after analyzing the correlation between the risk level and property of objects using linear regression, six middle sized industrial system has been used to propose the correlation model of size and Number of Classes(NOC), size and Number of Methods(NOM), complexity and NOC, and complexity and NOM. Among of six systems 5 systems(except S06) have high correlation between size(LOC) and NOM, and four systems(except S04 & S06) have high correlation between complexity and NOC / NOM. As Web software architecture with three sides of Server, Client and HTML, complexity of each sides has been compared, two system(S04, S06) has big differences of each sides compleity values and one system(S06) has very higher complexity value of HTML, So the risk level could be estimated through NOM to improve maintenance in case of that the system has no big differences of each sides complexity.

• Journal of the Korea Society of Computer and Information
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• v.18 no.12
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• pp.217-223
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• 2013

The purpose of this paper is to compare and analyze TOEIC scores of two kinds of courses opened at a university and the distribution of TOEIC scores of two groups. In addition, this paper will examine the ability of participants and the used instructional materials and equipment. The university has two kinds of TOEIC courses; one is a four-week intensive course opened in summer and winter vacations, where students participate in the classes from 9:00 a.m. to 4:00 p.m. The other is a regular TOEIC course, offering one-hour class every day from Monday to Friday during the university semester (15 weeks). This paper points out how important, the EFL/ESL teacher education, teaching materials, teaching methods and e-learning in operating more effective classes. The intensive TOEIC course and the regular TOEIC course include 120 hours and 75 hours a semester, respectively. Unfortunately, both courses have such a limited amount of time that students cannot achieve their fluent and perfect command of English. For Korean student to master English in a limited amount of both time and resources, the development of effective and qualitative EFL/ESL Intensive courses is essential.

• Journal of Species Research
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• v.8 no.2
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• pp.197-214
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• 2019

The taxonomic hierarchy of the phylum Proteobacteria was assessed, after which the isolation and classification state of Proteobacteria species with valid names for Korean indigenous isolates were studied. The hierarchical taxonomic system of the phylum Proteobacteria began in 1809 when the genus Polyangium was first reported and has been generally adopted from 2001 based on the road map of Bergey's Manual of Systematic Bacteriology. Until February 2018, the phylum Proteobacteria consisted of eight classes, 44 orders, 120 families, and more than 1,000 genera. Proteobacteria species isolated from various environments in Korea have been reported since 1999, and 644 species have been approved as of February 2018. In this study, all novel Proteobacteria species from Korean environments were affiliated with four classes, 25 orders, 65 families, and 261 genera. A total of 304 species belonged to the class Alphaproteobacteria, 257 species to the class Gammaproteobacteria, 82 species to the class Betaproteobacteria, and one species to the class Epsilonproteobacteria. The predominant orders were Rhodobacterales, Sphingomonadales, Burkholderiales, Lysobacterales and Alteromonadales. The most diverse and greatest number of novel Proteobacteria species were isolated from marine environments. Proteobacteria species were isolated from the whole territory of Korea, with especially large numbers from the regions of Chungnam/Daejeon, Gyeonggi/Seoul/Incheon, and Jeonnam/Gwangju. Most Halomonadaceae species isolated from Korean fermented foods and solar salterns were halophilic or halotolerant. Air-borne members of the genera Microvirga, Methylobacterium, and Massilia had common characteristics in terms of G+C content, major respiratory quinones, and major polar lipids.