• The KIPS Transactions:PartB
• /
• v.19B no.1
• /
• pp.31-36
• /
• 2012

In recent years, there has been increasing interest in recommender systems which provide users with personalized suggestions for products or services. In particular, researches of collaborative filtering analyzing relations between users and items has become more active because of the Netflix Prize competition. This paper presents the reinforcement learning approach for collaborative filtering. By applying reinforcement learning techniques to the movie rating, we discovered the connection between a time sequence of past ratings and current ratings. For this, we first formulated the collaborative filtering problem as a Markov Decision Process. And then we trained the learning model which reflects the connection between the time sequence of past ratings and current ratings using Q-learning. The experimental results indicate that there is a significant effect on current ratings by the time sequence of past ratings.

• Journal of Digital Convergence
• /
• v.12 no.8
• /
• pp.329-335
• /
• 2014

Collaborative filtering has been popular in commercial recommender systems, as it successfully implements social behavior of customers by suggesting items that might fit to the interests of a user. So far, most common method to find proper items for recommendation is by searching for similar users and consulting their ratings. This paper suggests a new similarity measure for movie recommendation that is based on genre interest, instead of differences between ratings made by two users as in previous similarity measures. From extensive experiments, the proposed measure is proved to perform significantly better than classic similarity measures in terms of both prediction and recommendation qualities.

• The Journal of Society for e-Business Studies
• /
• v.19 no.3
• /
• pp.125-141
• /
• 2014

Nowadays, overflowing data produced every second from the internet make people to be difficult to search for the useful information. That's why people have invented and developed unique tools that they get some relevant information. In this paper, the recommender system, one of the effective tools, is used and it helps us to get the useful information that we want by using demographic information to predict new items of interest. The demographic recommender system in this paper computes users' similarity using demographic information, age and gender. So we performed demographic analysis on movie ratings on Internet Movie Database (IMDB) web site that movies are rated by thousands of people, where users submitted a movie rating after they watched a recent popular film. Meanwhile, we can understand that user's ratings, among various determinants of box office, is very essential factor in the study on recommendation of movie. This paper is aimed at analyzing movie average ratings directly given by film viewers, categorizing them into groups by sex and age, investigating the entire group and finding the representative group by examining it with F-test and T-test. This result is used to promote and recommend for the target group only. Therefore, this study is considerably significant as presenting utilization for movie business as well as showing how to analyze demographic information on movie ratings on the web.

• Journal of Information Science Theory and Practice
• /
• v.2 no.3
• /
• pp.18-28
• /
• 2014

Reddit is a large user generated content (USG) website in which users form common interest groups and submit links to external content or text posts of user-created content. The web site operates on a voting system whereby registered users can assign positive or negative ratings to both submitted content and comments made to submitted content. While Reddit is a pseudonymous site, with users creating usernames but providing no biographical data, an informal survey posted to a large shared interest community yielded 734 responses including age and gender of users. This provided a large amount of contextual biographical data with which to analyse user profiles at the first level of Computer Mediated Discourse Analysis (CMDA), articulated by Susan Herring. The results indicate that older Reddit users both formulate more complex writing and enjoy more success when rated by other users. Gender data was incomplete and as such only tentative results could be proposed in that regard.

• KDI Journal of Economic Policy
• /
• v.43 no.3
• /
• pp.1-32
• /
• 2021

With CB data in South Korea, this study examines whether the credit risk of borrowers changes when the regulation on bank mortgage supply is relaxed. We analyze the effect of deregulation on LTV and DTI limits in the Seoul-metropolitan area in August 2014 with a difference-in-difference approach. We find that the probability of delinquency is lower in the Seoul metropolitan area after the deregulation than in other urban areas. The effect is noticeable among low-income and low-credit borrowers. We also find that borrowers change their debt structure to reduce the interest costs utilizing their improved access to bank mortgages. The findings suggest the necessity to consider the burden of the high interest costs of unsecured loans for debtors with low incomes and low credit ratings in designing housing finance regulations.

• The Korean Journal of Community Living Science
• /
• v.28 no.3
• /
• pp.461-479
• /
• 2017

This study was to investigate the appearance orientation and body shape management of adolescents in Daejeon. A survey was performed from December 16th~28th 2015 and 355 respondents were collected for analysis. 45.9% of the subjects were middle school students, whereas 54.1% of them were high school ones. The female and high school students tended to show higher ratings in lookism tendency and interests in beauty care, whereas male and middle school students tended to show higher ratings in physical satisfaction than the others. More than 40% of the respondents perceived them fatter than the standard weight, in particular, girls and the ones with opposite-sex friend perceived them fatter than their actual conditions. On body shape satisfaction, female and high school students indicated lower satisfaction. For body shape management, 75% of the female and 40% of the male students had tried weight control. The frequency and the duration time of exercise had higher for boys than girls, and the ones with opposite-sex friend than without. For methods of weight control, girls were more likely to do diet control, whereas boys were more committed to exercise. In general, students with high appearance orientation tended to control taking snacks and fast food or did diet control for body shape management. Conclusively, continued interest and guidance, not only at home but also in school, is required for students so that they can do proper body shape management to fulfill their appearance orientation and they will improve academic performance by gaining confidence through their appearance satisfaction.

• Korean Journal of Construction Engineering and Management
• /
• v.19 no.1
• /
• pp.90-102
• /
• 2018

In preparation of the increase in the domestic debts and the rise in the US interest rate, the Korean government has started to strengthen the regulation on the property market since 2017. So, it is likely that the sales in the domestic construction market would be decreased. Even in the overseas plant projects market, as there has been the continuous increase in the cost and the resulting increase in the losses, it looks hard for the large construction companies to keep their credit ratings as they are now. This study is designed to check Korean government's property policy and any possible problems caused by the overseas and domestic economic environment, which include the property market policy, interest rate, rise in the property price and lackluster sales in housing market. It showed the change in the credit ratings by finding out the sales, work capability, sales in non-governmental projects, operating profits and PF contingency liabilities. For this study, the questionnaires were sent to 30 practical experts to analyze the effect of the risk factor on the outside credit rating of large construction companies.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.14 no.2
• /
• pp.793-803
• /
• 2013

This study was performed to determine the usefulness of scanpath similarity analysis as one of new web usability testing. The 5 websites of public institutions were used and 15 students participated. First of all, eye movements were tracked and visual appeal ratings were measured as participants freely viewed each website for 3 seconds. Subsequently in continuously tracking the eye movements we asked the participants to perform 17 missions. Finally, in interview the participants rated on satisfaction, awareness, and mission difficulty. Results of this study showed that scanpath similarity had a significant relationship with both the visual appeal ratings(first impression) and the satisfaction. In other words, higher the visual appeal ratings were related to higher scanpath similarity. This result showed that measurement such as scanpath similarity of eye movements could become an objective index for usability testing instead of subjective evaluation such as the satisfaction. We discussed possibility that the usability testing by using the scanpath similarity with both fixation and duration on eye movements will find more appropriately inference on observers' experiences in websites.

• Journal of Intelligence and Information Systems
• /
• v.28 no.1
• /
• pp.311-328
• /
• 2022

Because of the spread of smartphones due to the development of information and communication technology, online shopping mall services can be used on computers and mobile devices. As a result, the number of users using the online shopping mall service increases rapidly, and the types of products traded are also growing. Therefore, to maximize profits, companies need to provide information that may interest users. To this end, the recommendation system presents necessary information or products to the user based on the user's past behavioral data or behavioral purchase records. Representative overseas companies that currently provide recommendation services include Netflix, Amazon, and YouTube. These companies support users' purchase decisions by recommending products to users using ratings, purchase records, and clickstream data that users give to the items. In addition, users refer to the ratings left by other users about the product before buying a product. Most users tend to provide ratings only to products they are satisfied with, and the higher the rating, the higher the purchase intention. And recently, e-commerce sites have provided users with the ability to vote on whether product reviews are helpful. Through this, the user makes a purchase decision by referring to reviews and ratings of products judged to be beneficial. Therefore, in this study, the correlation between the product rating and the helpful information of the review is identified. The valuable data of the evaluation is reflected in the recommendation system to check the recommendation performance. In addition, we want to compare the results of skipping all the ratings in the traditional collaborative filtering technique with the recommended performance results that reflect only the 4 and 5 ratings. For this purpose, electronic product data collected from Amazon was used in this study, and the experimental results confirmed a correlation between ratings and review usefulness information. In addition, as a result of comparing the recommendation performance by reflecting all the ratings and only the 4 and 5 points in the recommendation system, the recommendation performance of remembering only the 4 and 5 points in the recommendation system was higher. In addition, as a result of reflecting review usefulness information in the recommendation system, it was confirmed that the more valuable the review, the higher the recommendation performance. Therefore, these experimental results are expected to improve the performance of personalized recommendation services in the future and provide implications for e-commerce sites.

• Journal of Science Education
• /
• v.33 no.2
• /
• pp.248-257
• /
• 2009

The purpose of this study is to investigate the learning achievement of students who has taken the play-based and activity-oriented programs in the class. These new science class programs and instrument to measure student learning achievement were developed for the "Constellation Favorite" lesson of 4th grade students and Those are verified by science education experts, teachers in serve. The subjects of this study consist of 121 students in four classes who were selected on the basis of midterm examination result before teaching treatment. They were divided into two categories with two classes per each category, one class for experimental group and the other class for control group. The experimental groups were given five classes including five play-based class programs. The control groups were given five conventional instruction-type classes. The students were given questionnaires to test their interest ratings. The results show about 17% increase of their learning achievement with (p<0.005) by independent sample T-test method and 40% increase of interest rating in play-based class sample compared to normal class sample. In conclusion, the play-based science class program is found to enhance the students' learning achievement and to interest the students more effectively.