• Journal of Intelligence and Information Systems
• /
• v.25 no.4
• /
• pp.89-103
• /
• 2019

Recently, various approaches to recommendation systems have been studied in terms of the quality of recommendation system. A recommender system basically aims to provide personalized recommendations to users for specific items. Most of these systems always recommend the most relevant items of users or items. Traditionally, the evaluation of recommender system quality has focused on the various predictive accuracy metrics of these. However, recommender system must be not only accurate but also useful to users. User satisfaction with recommender systems as an evaluation criterion of recommender system is related not only to how accurately the system recommends but also to how much it supports the user's decision making. In particular, highly serendipitous recommendation would help a user to find a surprising and interesting item. Serendipity in this study is defined as a measure of the extent to which the recommended items are both attractive and surprising to the users. Therefore, this paper proposes an application of serendipity measure to recommender systems to evaluate the performance of recommender systems in terms of recommendation system quality. In this study we define relevant or attractive unexpectedness as serendipity measure for assessing recommendation systems. That is, serendipity measure is evaluated as the measure indicating how the recommender system can find unexpected and useful items for users. Our experimental results show that highly serendipitous recommendation such as item-based collaborative filtering method has better performance than the other recommendations, i.e. user-based collaborative filtering method in terms of recommendation system quality.

• Korean Journal of Comparative Education
• /
• v.23 no.5
• /
• pp.53-75
• /
• 2013

This article explores the impact of mergers on the experiences of students. A case design is used to gain an in-depth understanding of the students in a Korean university that was combined with a two-year college in 2007. Semi-structured interviews of 11 direct entrants, 5 transfer students, and 7 professors were conducted in 2010 for the data collection. The results suggest that mergers do not necessarily ensure the integration of the students involved. Since mergers pose enormous challenges to both transfer students and direct entrants, university leaders need to give careful attention to students' persistence and integration as the campus changes. The results also reveal that students' experience of mergers may be affected by cultural backgrounds as well as the hierarchical structure of higher education. In Korean society, where credentialism prevails, mergers can have different impacts on students who come from initial institutions of differing perceived quality, and thus mergers may incite tension among the students. In light of these concerns, this study's findings highlight the importance of student integration as a key element in mergers.

• Journal of Practical Engineering Education
• /
• v.10 no.1
• /
• pp.73-79
• /
• 2018

The purpose of this study is to explore the supporting scenario to promote vocational training in North Korea in terms of cooperation level. To this end, we have embarked on a regional and industry based vocational training program by predicting the political and social situation of North Korea and staging three scenarios systematically. These scenarios were designed originally based on the Futures Group methodology. The first scenario is to establish a technical training center in one area, focusing on the electrical, electronics, and clothing sectors. The second scenario is to set up a pilot campus of vocational training college in one region by selecting the electric, electronic, and automobile industries as its main industries. The third scenario is to establish five vocational training college campuses in North Korea, focusing on electricity and electronics, IT manufacturing, telecommunications, heavy industry, and women-specialized industries. We suggested the followings: First, establishing goals and strategies for North Korean vocational training and establishing road maps. Second, the North Korean vocational training governance system needs to be established. Third, R & D infrastructure for vocational training needs to be established. Fourth, HRD and HRM system in North Korea vocational training field needs to be established. In addition, the role of public and private employment services centers to provide them should be strengthening.

• Journal of Convergence for Information Technology
• /
• v.9 no.6
• /
• pp.121-129
• /
• 2019

The purpose of this study is to investigate how the variables of parenting styles and dependency on the smart phone affect college students' satisfaction to campus life, to seek the better ways for the college students to fit into the new environment, and to offer the practical tips based on our findings. In this study, we applied the regression analysis to verify the relationship among the variables related to the satisfaction to university life and the mediating effect of dependency on the smart phone. The results of this study suggest that the positive rearing attitude, which is the subfactor of parenting styles, has a negative effect on the dependency on the smart phone, and that dependency on the smart phone has a negative effect on the satisfaction to college life. At the same time it is found out that the negative rearing attitude has a positive effect on dependency on the smart phone, and that dependency on the smart phone has a negative effect on the satisfaction to the college life. In addition, the dependency on the smart phone has a partial mediating effect on the relationship between the positive/negative rearing attitudes and dependency on the smart phone. Based on these findings, we recommended the better ways to improve college students' satisfaction to their college lives.

• Journal of the Korean Applied Science and Technology
• /
• v.38 no.3
• /
• pp.651-661
• /
• 2021

Eruca sativa, called arugula, is a perennial plant in the Brassicaceae family, an edible plant commonly used in Italian cuisine. To study as a cosmetic material application E. sativa was extracted with 70% ethanol (ES). Then ES was fractionated using n-hexane, chloroform, ethyl acetate, n-butyl alcohol and water (EHex, EEA, ECHCl₃, EBuOH and EDW). EEA showed mushroom tyrosinase inhibitory activity. ES, EEA and EBuOH showed inhibition of tyrosinase activity. As a result, ES is expected to have skin whitening efficacy. ES was applied to 0.05, 0.1% the toner and emulsion formulation to test the stability. The anti-microbial activity of eight bacteria and fungi including Staphylococcus aureus and Propionibacterium acnes which cause dermatitis and acne was evaluated. EEA showed effects in all of microorganisms. The toner and emulsion containing ES with 0.05, 0.1% were passed in the challenge test. At -20, 4, 25, 55 ℃ and daylight, there was no significant change on pH, viscosity for 4 months. However, emulsions had phase separation phenomenon at 55 ℃, so the base formulation needs improvement. In addition, through the skin penetration test, EEA penetrated 0.058% in 6 hr, predicting the clinical efficacy. This means that E. sativa can contribute whitening agent and the synergistic effect of preservatives.

• Journal of Advanced Navigation Technology
• /
• v.24 no.6
• /
• pp.566-572
• /
• 2020

In a wireless power transmitter, the characteristics and effects of wireless power transmission between two induction coils are investigated, and a power converter circuit and a battery charger/discharger circuit using wireless power transmission technology are proposed. The advantage of wireless power transmitters and wireless chargers is that, instead of the existing plug-in-mounted wired charger (OBC; on-board charger), the user can wirelessly charge the battery without connecting the power source when charging power to the battery. There is. In addition, the advantage of wireless charging can bring about an energy efficiency improvement effect by using the secondary side rectifier circuit and the receiving coil, but the large-capacity long-distance wireless charging method has a limitation on the transmission distance, so many studies are currently being conducted. The purpose of the study is to study the transmitter circuit and receiver circuit of a wireless power transmission device using a primary coil, a secondary coil, and a half bridge series resonance converter, which can transmit power of a non-contact type power transmitter. As a result, a new topology was applied to improve the power transmission distance of the wireless charging system, and through an experiment according to each distance, the maximum efficiency (95.8%) was confirmed at an output of 3 kW at an 8 cm transmission distance.

• Journal of the Korea Institute of Building Construction
• /
• v.22 no.6
• /
• pp.543-551
• /
• 2022

The mechanical performance and vibration damping ratio performance of a specimen according to the polymer mixing rate were evaluated for polymer modified mortar. As a polymer, Styrene Butadiene Rubber(SBR) liquid polymer with a solid content of about 49~51% was used, and the polymer content was increased by liquid 5%. The specimen was 40*40*160(mm), and after curing, compressive strength, flexural strength, and vibration damping ratio were measured using the ultrasonic pulse method. As a result, it was found that the compressive strength decreased as the polymer was mixed, but the flexural strength was increased. The vibration damping ratio increased by 11% at 5% polymer, 28% at 10% polymer, 33% at 15% polymer, and 72 at 20% polymer. I was found that the incorporation of the polymer was very effective to reduce the vibration of the mortar. In addition, through SEM and SEM-EDS analysis, it is determined that the cause of vibration reduction due to polymer mixing is that the polymer film formed in the transition zone of aggregate and internal voids buffered the vibration of the mortar inside. Taken together, in the scope of this study, the appropriate polymer mixing ratio for reducing the vibration of mortar is judged to be about 7.5%.

• Korean Journal of Culture and Social Issue
• /
• v.23 no.2
• /
• pp.159-181
• /
• 2017

The current study is the first attempt to review the [Korean Journal of Psychology: Culture and Social Issues] systematically. For the past 22 years from 1994 to 2015, 464 articles have been published in the Journal. We analyzed the 337 empirical research articles, with respect to their objectives, predictor and outcome variables, and their methodologies. Most of the studies dealt with variables at individual level; some dealt with variables of the community and socio-cutural environment level. Many of the studies included general population, not necessarily social minorities. The results were compared with the literature on the social issues that Koreans perceive as social issues. Also it is noteworthy that many studies failed to specify such demographic characteristics as age, gender, and locality of their participants in the articles. Based on the analysis results, we discussed the roles of psychology and of the Journal in the contemporary Korean context.

• Journal of the Korean Society of Industry Convergence
• /
• v.26 no.6_2
• /
• pp.1011-1017
• /
• 2023

In this study, the harmless crack size (a_hml) by double shot peening (DSP) using shot balls with different diameters was evaluated on carburized, quenched-tempered SCM822H steel. The minimum crack size (a_NDI) detectable by non-destructive inspection was also evaluated. The relationship between the crack size (a_25,50) that reduces the fatigue limit by 25% and 50% and a_hml was evaluated. The residual stress of DSP was greater in SP_(0.6+0.08) than SP_(0.8+0.08) and appeared deeper in the depth direction. In addition, the hardness below the surface appeared larger. The fatigue limit of DSP increased 2.07 times and 1.95 times compared to non-SP. All a_hml of the DSP specimen was determined at the depth (a). The compressive residual stress distribution affects a_hml, and the a_hml of SP_(0.6+0.08), which has a large compressive residual stress and a high fatigue limit, appeared large. a_hml of SP_(0.6+0.08) introduced deeper than the residual stress of SP_(0.8+0.08) is larger in the range of As=1.0-0.3. Since the residual stress in the thickness direction has a greater effect on a_hml than the residual stress at the surface, it is necessary to introduce it more deeply. The relation of a_hml, a_25,50, and a_NDI were evaluated in the point for safety and reliability.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
• /
• v.17 no.5
• /
• pp.95-104
• /
• 2022

This study aims to find out the influence of the intolerance of uncertainty on entrepreneurial intention by focusing on the start-up support system awareness. While most of existing studies focused on the positive psychological variables and individual environmental characteristics influencing on the entrepreneurial intention, this study has taken a look at the influence of the intolerance of uncertainty as the psychological variable to the entrepreneurial intention to negatively act on the entrepreneurial intention. As a result of the analysis, the intolerance of uncertainty under the control of entrepreneurship and gender is shown to have the negative (-) influence on the entrepreneurial intention and has high level of recognition on the start-up support system perception, and the start-up support system perception is confirmed to have positive (+) influence on the entrepreneurial intention. And, it also indicates that, with respect to the influence of the intolerance of uncertainty on the entrepreneurial intention, the start-up support system perception has the partial medium effect. Following this result of the study, it provides following indications: First the existing studies on the entrepreneurial intention had not covered the intolerance of uncertainty but it is confirmed as the psychological variable with negative influence on the entrepreneurial intention. Second, it is feasible for the preliminary start-up businesses may turn the fear on start-up failure into positive entrepreneurial intention with the start-up support system perception as the leading vehicle. And, third, based on the result, the government should enhance the start-up support system perception even more by seeking ways of efficient publicity to enable more preliminary start-up businesses to participate in diverse start-up support policies. Lastly, it discusses the limitations of this study as well as proposal for ensuing study plans.