• Journal of KIISE:Software and Applications
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• v.32 no.6
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• pp.542-553
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• 2005

Recommendation systems analyze user preferences and recommend items to a user by predicting the user's preference for those items. Among various kinds of recommendation methods, collaborative filtering(CF) has been widely used and successfully applied to practical applications. However, collaborative filtering has two inherent problems: data sparseness and the cold-start problems. If there are few known preferences for a user, it is difficult to find many similar users, and therefore the performance of recommendation is degraded. This problem is more serious when a new user is first using the system. In this paper we propose a method of integrating additional feature information of users and items into CF to overcome the difficulties caused by sparseness and improve the accuracy of recommendation. In our method, we first fill in unknown preference values by using the probability distribution of feature values, then generate the top-N recommendations by applying collaborative filtering on the modified data. We call this method of filling unknown preference values as data blurring. Several experimental results that show the effectiveness of the proposed method are also presented.

• Journal of The Korean Association For Science Education
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• v.26 no.2
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• pp.222-231
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• 2006

The purposes of this study were to survey internal engagement in science fair and explore the causal relationship between internal engagement and motivation for participation. A written questionnaire on queries into motivation for participation and internal engagement were developed and tested. The subjects were 1066 students from 4th to 9th grade who had participated in the Youth Science Contest under the auspices of the Korea Science Foundation. Interest and commitment were selected as constructing factors of internal engagement. Through exploratory factor analysis, preference, reward, and social motivation were determined to be the factors affecting the motivation to participate. Boys showed higher internal engagement than girls, and interest and commitment were found to be higher in elementary school students(p<0.01). There was no difference in interest among elementary school students; however, fourth grade students showed lower commitment than other students(p<0.01). Ninth grade students showed the lowest interest and commitment among junior high school students(p<0.01). To explore the causal relationship between internal engagement and factors influence internal engagement, path analysis was used. The selected model illustrated how reward motivation affected commitment directly, and how preference motivation affected interest directly but only commitment indirectly through interest. Reward motivation affected commitment with a standardized direct effect coefficient of 0.17. Preference motivation affected interest with a standardized direct effect coefficient of 0.75 and commitment with a standardized total effect coefficient of 0.63(direct effect; 0.27 and indirect effect; 0.36). In addition, interest affected commitment with a standardized direct effect coefficient of 0.49. Social motivation did not affect interest and commitment and reward motivation did not affect interest.

• Journal of the Korean Applied Science and Technology
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• v.39 no.4
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• pp.507-516
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• 2022

The purpose of this study was to investigate the effect of rotational preference on body stability based on COP and EMG analysis in an quiet standing after turn in the left and right directions. The subjects of this study were 16 subjects with a high lateral preference for the right hand and foot. The subjects of this study were 16 subjects with high unilateral preference for the right hand and foot, and three rotational direction conditions (QS: quiet standing, LT: 10 turns on the left, RT: 10 turns on the right) were performed. In order to evaluate the stability in an quiet standing after turning, the results were derived and analyzed using a COP plate and an EMG. As a result of the study, LT and RT were larger than QS for all COP variables, but there was no difference according to the direction of turning. In EMG, RT showed larger muscle activity than the QS according to the rotational direction in left and right gastrocnemius. In conclusion, although all subjects had a high right lateral preference, there was no effect of rotational preference in COP, and gastrocnemius showed the effect of rotational preference.

• Science of Emotion and Sensibility
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• v.9 no.2
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• pp.101-109
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• 2006

If a salesperson is able to juage consumers' purchasing preferences by looking at their eyebrows shapes, he might be able to set up his sales strategies that will be helpful for the sales. In order to set up this kind of strategy, the difference of purchasing preferences in relation to the eyebrows shapes must be defined clearly. The purpose of this study is to analyze the difference of purchasing preferences according to eyebrows shapes. We group eyebrows shapes into five classes in physiognomy, and Analyze the difference of purchasing preferences according to eyebrows shapes. The result shows that compared with people with rising tails of eyebrows, people with declined ones prefer common, simple, gentle and noble clothing image.

• Science of Emotion and Sensibility
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• v.8 no.2
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• pp.129-135
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• 2005

The purposes of this study were to investigate the subjective preference for odors, which has been an important factor for selecting fabric softner, and to identify the structure of sensibility of odors. Among six different odors, the subjects preferred freesia, blue bianca, violet, herb, green tea, and peach, in that order. Compared to male subjects, female subjects preferred freesia, herb, and blue bianca. The structure of odor sensibility to freesia showed 5 different factors and the odor sensibility to peach showed 6 different factors. Therefore, the structure of odor sensibility according to different odors was a bit different. Common factors of freesia odor and peach odor were aesthetics, character, excitement and intensity.

• Journal of KIISE
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• v.43 no.10
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• pp.1144-1153
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• 2016

Group recommendation analyzes the characteristics and tendency of a group rather than an individual and provides relevant information for the members of the group. Existing group recommendation methods merely consider the average and frequency of a preference. However, if the users' preferences have large deviations, it is difficult to provide satisfactory results for all users in the group, although the average and frequency values are high. To solve these problems, we propose a method that considers not only the average of a preference but also the deviation. The proposed method provides recommendations with high average values and low deviations for the preference, so it reflects the tendency of all group members better than existing group recommendation methods. Through a comparative experiment, we prove that the proposed method has better performance than existing methods, and verify that it has high performance in groups with a large number of members as well as in small groups.

• Science of Emotion and Sensibility
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• v.8 no.3
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• pp.253-263
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• 2005

In this study, the basic purpose was to identify the characteristics of the perception response of the elements that have an influence on the information search process for an assessment of product preference. Also, the relationship between the characteristics and the preference of products were reviewed in terms of the experience of the use of products. For this, photos of mobile phones and proposal-type products were selected and the experimental stimulant and experiments were conducted in two steps. In the first experiment, observations were made on the photos of the proposed products and they were arranged in the order of preference. In the second experiment, the part with the first attention in the preference assessment was marked by using the product photos that were previously selected and ranking them from 1 to 10. Two conclusions were obtained from the results of the experiment. First, the experimental memory information with the experience of the use of the products activates an interpretational response to the various constitutional elements included in the object for conception in the process of a preference rating. Second, no product use experience induces the reaction that perceptually accepts the esthetical elements included in the object for perception, regardless of preference.

• Journal of the Korean Chemical Society
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• v.54 no.5
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• pp.643-649
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• 2010

In this study, the relationships among high school students' epistemological views on theory and data, science process skills, the perceptions of the preferred laboratory learning environment and attitudes toward laboratory work were investigated. The results indicated that science process skills, all subcategories of the perceptions of the preferred laboratory learning environment (student cohesiveness, open-endedness, integration, rule clarity, and material environment) and attitudes toward laboratory work were significantly correlated with epistemological views on theory and data. The results of multiple regression analysis revealed that science process skills, open-endedness and material environment and attitudes toward laboratory work significantly predicted epistemological views on theory and data.

• Journal of the Korean earth science society
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• v.31 no.2
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• pp.172-184
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• 2010

This study is to investigate the problem solving styles according to the left /right brain preference among earth science gifted students. We took the R/LCT and the test of BPI to investigate the brain preference of earth science gifted students (N=16), and took S-CPST to investigate the problem solving styles on them. In the R/LCT, the earth science gifted students were classified into 3 groups (8 left-brain preference students, 7 right-brain preference students, 1 middle-brain preference student). In the BPI, 8 students had the appearance of left-brain preference, whereas 8 students had the appearance of right-brain preference. According to the result of S-CPST, first the left brain preference students tended to resolve a problem into simple components, then they put together each simple component. They prefer to solve a problem using numbers and mathematical signs logically, but they were afraid of giving trouble to describe own idea with pictures. Whereas the right brain preference students solved a problem with 3 steps. First, they saw an overall form of problem. Second, they tried to analyze each simple component of it, and then, made up all in one. Also, the right brain preference students observed the intuitive pattern of problem first, and then suggested the various problem solving methods later, and they took a solving plan using a picture in detail. In sum, earth science gifted students are unequal in problem solving styles according to the left/right brain preference. Thus, a teaching-learning method needs to be developed based on left/right brain preference for more effective gifted education.

• Journal of Science Education
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• v.44 no.1
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• pp.61-73
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• 2020

Teachers are the most important factor contributing to determining the quality of education. Therefore, the quality of teachers should be improved to enhance the quality of education. Teacher's competencies are defined as the skills required for teaching profession, that is, the ability to perform not only in teaching activities, but also in guidance and class management. The purpose of this study is to analyze the competencies of science teachers that elementary, middle and high school students want. To this end, 332 elementary, middle and high school students were asked to describe their preferred science teacher's competencies and avoiding science teacher's competencies as an open questionnaire. The resulting concepts were analyzed by semantic network analysis (SNA). The results of this study are as follows: 1) The competencies of science teachers that students prefer varied. This suggests that most students think positively about science teachers. In addition, it is possible to show students the positive or preferred competencies of teachers in various ways. 2) The students wanted teachers to explain the theories and concepts related to scientific phenomena through experiments. They also preferred hands-on activities and experience in science class. 3) The students put emphasis on the class-related contents in the competencies of science teachers. Accordingly, the image of science teachers and science itself should be enhanced through the improvement of science teaching methods and positive attitudes toward students. It is expected that further research on the image according to specific teaching methods of science teachers will be conducted based on the findings of this study.