• Resources Recycling
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• v.29 no.6
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• pp.104-113
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• 2020

Bubble size in froth flotation has long been recognized as a key factor which affects the bubble residence time, the bubble surface area flux (Sb) and the carrying rate (Cr). This paper presents method of bubble size measurement, relationship between operating variables and gas dispersion properties in flotation column. Using high speed camera and image analysis system, bubble size has been directly measured as a function of operating parameters (e.g., superficial gas rate (Jg), superficial wash water rate (Jw), frother concentration) in flotation column. Relationship compared to measured and estimated bubble size was obtained within error ranges of ±15~20% and mean bubble size was 0.718mm. From this system the empirical relationship to control the bubble size and distribution has been developed under operating conditions such as Jg of 0.65~1.3cm/s, Jw of 0.13~0.52cm/s and frother concentration of 60~200ppm. Surface tension and bubble size decreased as frother concentration increased. It seemed that critical coalescence concentration (CCC) of bubbles was 200ppm so that surface tension was the lowest (49.24mN/m) at frother concentration of 200ppm. Bubble size tend to increase when superficial gas rate (Jg) decreases and superficial wash water rate Jw and frother concentration increase. Gas holdup is proportional to superficial gas rate as well as frother concentration and superficial wash water rate (at the fixed superficial gas rate).

• Journal of Advanced Navigation Technology
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• v.25 no.3
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• pp.248-255
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• 2021

The main causes of the July 2013 OZ 214 accident were poorly performed approach and the failure to recognize the autothrottle in the HOLD position which the automated speed control was not provided. The pilots late decision for go-around was also a critical factor leading to the accident. The B777 POM restricts the use of FLCH mode beyond the FAF. This research utilized the QAR data of an airline's B777 fleet in the period of two years where 44 cases were found. In many cases, the FLCH mode was used for rapid descent from an higher than normal situation. In addition, in the base turn, continuous use of FLCH mode even when the path was below the glide path were observed. Airports with elevation above 500 ft MSL had a higher rate of occurrence. In this research, the proper descent planning and vertical path monitoring, and the adherence to the limitation set in the manuals and the stabilized approach criteria were re-emphasized as mitigation to reduce event occurences.

• The Journal of the Korea Contents Association
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• v.21 no.8
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• pp.213-220
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• 2021

The purpose of this study is to pave the way to promote the institutional commitment of the students enrolled by identifying the factors that affects on their institutional commitment. The data collection was conducted starting from November 19, 2020 until November 26, 2020 by using online questionnaires and 220 participants were from C-university students in Chang-won, Kyung-nam Province. As a result of analysis, the average score for institutional commitment was 3.30, the average level of satisfaction of university life was 3.62, the cultural climate was 3.39 and the level of satisfaction for extracurricular program was 3.48, which was in high range. Institutional commitment has a positive correlation between the level of satisfaction of university life, the level of satisfaction for extracurricular programs(p<.001). The most critical factor that affects the institutional commitment was the level of satisfaction of university life and the level of satisfaction for extracurricular programs, the cultural climate in order. The result can be interpreted that institutional commitment is influenced by students' major and the level of satisfaction of university life and the level of satisfaction for extracurricular programs, and the level of satisfaction of university life has relatively high level of influence out of other factors, indicating that the effort to improve the institutional commitment of the students is needed at the collegiate level.

• Journal of Korea Entertainment Industry Association
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• v.15 no.2
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• pp.1-10
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• 2021

The purpose of this study is to explore a significant HPWS(High Performance Work System) model for the entertainment industry. HPWS is one of the most studied themes for managing human resources as well as a set of practices to elicit employees' commitment to an organization. Recently, the entertainment industry is growing rapidly, but it is difficult for entertainment firms to retain a stable profit unlike the manufacturing industry. This is because the performance of entertainment business tends to rely heavily on the capabilities and synergy of human resources. In order to suggest a systematic way to manage these, this research identified an effective HPWS model for entertainment business and provides a competitive advantage to entertainment firms, using ANP(Analytic Network Process). ANP is a multicriteria decision making technique that allows dependences and feedbacks among decision elements in the hierarchical or network structures in a holistic manner. The pairwise comparison data that prioritized the criteria of HPWS was collected from 28 team leaders in entertainment firms. According to our results, the most critical factor for HPWS in entertainment business is "employee involvement in decision-making." The sub-factors such as "open communication," "distributive decision-making," and "performance-driven reward" have a greater effect. These findings could provide implications for entertainment firms to determine which practices should be taken into account to accomplish HPWS.

• The Journal of Korean Society for School & Community Health Education
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• v.23 no.4
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• pp.17-28
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• 2022

Objectives: This study aimed to provide the measures for improving the self-directed learning ability and the reference data for substantializing the educational programs by verifying the main factors affecting the self-directed learning ability of dental hygiene students in reality when the learners' autonomy is emphasized than ever. Methods: From June 20 to July 4, 2022, an online survey was conducted targeting total 218 dental hygiene students. The collected data was analyzed by using the SPSS Program Version 22.0. Results: First, in the results of analyzing differences in detailed items of self-directed learning ability according to the general characteristics, the 'students who entered the department of dental hygiene by considering their aptitude and interest' showed higher results than the 'students who entered the department by considering their high school record'. Second, when the academic efficacy, study immersion, and problem-solving ability of dental hygiene students were higher, their self-directed learning ability was also high. Third, the factor that had the greatest effect on self-directed learning ability of dental hygiene students was problem-solving ability, which was followed by academic efficacy and study immersion. Conclusion: Putting together the results above, in order to cultivate the problem-solving ability of dental hygiene students, it would be necessary to operate the problem-solving-centered simulation course that could foster critical thinking, interactions with others, and creative approach and solution to problems in dental medical site. It would be also possible to improve their academic efficacy by applying the learning mentoring & one-to-one learning counseling program, and also strengthening proper feedbacks for learners. Moreover, the study immersion could be strengthened by developing and operating the emotion-based learning motivation program & learning coaching program through the process of verifying the potential and growth needs of learners, exploring one's own resources through learning diagnosis/introspection, and exploring the career-related vision for strengthening the learning motivation, which could have positive effects on the improvement of self-directed learning ability.

• The Journal of the Korea Contents Association
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• v.22 no.9
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• pp.1-18
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• 2022

This study critically analyzed the user experience (UX) of mobile applications, focusing on the advertising platforms of mobile applications for culture and arts content. This study aims to examine the direction for growth of the related mobile applications and propose alternative approaches to improve usability. In this study, a mobile app named 'Moviepre' was selected, and a heuristic evaluation was performed for in-depth exploration. For the selected case, the UX Honeycomb model was reconstructed to analyze useful, usable, desirable, findable, accessible, and credible elements of the case. First, since the users' preference for the price factor did not show a significant correlation with the usefulness of the content and the interface, it is necessary to make sure that the mobile application has unique values to gain a competitive advantage in the market. Second, by adopting customer path stages for analysis, the result indicated that users continuously interact with the service from the first moment they are aware of the mobile application. Third, if the user feels uncomfortable, it is likely that these factors hinder the establishment of a long-term relationship between the users and the mobile application. Finally, brand identity should be clearly established, and brand image strategy needs to be developed to satisfy users' expectations that high-quality culture and arts content will be available through the mobile application.

• Journal of Digital Convergence
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• v.20 no.5
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• pp.525-535
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• 2022

The purpose of this study is to identify the factors influencing the user's continuous usage intention of computer games. A research model was developed which shows that the independent variables of value, expectation confirmation, perceived enjoyment affect user satisfaction and continuous usage intention. To test the six hypotheses, survey data were collected from 104 respondents, and hypotheses tests as well as a confirmatory factor analysis were conducted using a partial least square analysis tool. The statistical analysis result showed that expectation confirmation had a significant positive effect on satisfaction, and satisfaction also had a strong positive effect on the game user's continuous usage intention. Perceived enjoyment showed a highly strong positive effect on satisfaction. In addition, satisfaction was found to have full mediation effects in the relationship between expectation confirmation and continuous usage intention, and perceived enjoyment and continuous usage intention respectively. This result provides an important implication that continuous usage intention occurs through user satisfaction, and also indicates the contribution of this study for the game industry. Another contribution of this study is to introduce critical independent variables from the marketing and information technology domains in order to explain continuous usage intention of computer games.

• Science of Emotion and Sensibility
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• v.26 no.2
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• pp.85-102
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• 2023

This study aims to examine whether emotional clarity predicts low levels of social interaction anxiety among senior citizens and to verify whether self-esteem and self-efficacy play a critical role as mediators between them. An online survey measuring emotional clarity, social interaction anxiety, self-esteem, and self-efficacy was conducted with 217 Korean senior citizens. The analysis revealed that emotional clarity in old age predicted lower social interaction anxiety. Besides, self-esteem mediated the relationship between emotional clarity and social interaction anxiety, while self-efficacy did not produce consistent results. That is, recognizing one's emotions increases one's self-esteem, which reduces social interaction anxiety, but this mediating effect could not be confirmed through self-efficacy. This result emphasizes that recognizing one's emotions in old age is an important factor in facilitating interaction with others, and shows that individuals can be comfortable in relational situations because emotional clarity increases one's self-esteem. Finally, the implications of this study and the future direction of this research area were discussed.

• Composites Research
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• v.36 no.4
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• pp.281-287
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• 2023

Environmental pollution from waste and the climate crisis, due to rising global average temperatures, are reaching critical levels threatening human survival. Research is ongoing across various fields to solve this problem, with a key focus on developing eco-friendly, carbon-neutral materials. Our study aimed to integrate natural fibers, known for their environmentally friendly properties and lower carbon emissions, with carbon fibers. In general, combining high-strength and low-strength materials results in intermediate properties. However, we found that certain properties in our study exceeded those of typical carbon fiber composite materials. To validate this, we produced both carbon fiber composite materials and carbon fiber/natural fiber hybrid composite materials. We then compared their mechanical properties using a range of specific tests. Our results revealed that the hybrid composite material exhibited superior bending strength and fracture toughness compared to the carbon fiber composite material. We also identified the underlying mechanisms contributing to this strength enhancement. This breakthrough suggests that the use of hybrid composite materials may allow the production of stronger structures. Moreover, this can play a significant role in mitigating environmental pollution and the climate crisis by reducing carbon emissions, a major contributing factor to these global challenges.

• Journal of Service Research and Studies
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• v.12 no.3
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• pp.45-59
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• 2022

This study attempted to investigate how the transformational leadership perceived by flowers of telemarketing organizations. In particular, this study explored the moderating effect of followership in the relationship between transformational leadership and organizational performance. To verify the research model, 321 surveys collected from 10 domestic call centers were analyzed. Reliability, correlation, factor analysis, and hierarchical regression analysis were performed, and as a result of the analysis, it was found that the transformational leadership in the telemarketing organizations had a positive effect on organizational performance. In addition, it was confirmed that goal consistency, proactive participation, critical thinking, and team spirit, which are the four sub-variables of followership, all have a positive (+) effect on organizational performance, and both goal consistency and proactive participation moderate the relationship between transformational leadership and organizational performance. Considering the special working environment of telemarketing organizations, the results of this study suggest the need for a corporate educational role to increase transformational leadership and followership and the need to build environments by setting up an atmosphere for members to exercise follow-up, and opening up communication structures for members to follow.