• Information Systems Review
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• v.9 no.2
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• pp.15-39
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• 2007

Mobile games have emerged as the most innovative entertainment technology, adding new revenue streams, taking advantage of the potential of wireless applications and service offerings. Mobile games, like any other types of computer game, offer a unique value for users in providing an exciting digital experience in virtual worlds. In this paper, we attempt to investigate the demographic factors which play critical roles in determining the level of playing times; classify mobile gamers based on their motives for playing games; and empirically test differences in their demographic factors and mobile game usage. Statistical results show that significant differences in playing times exist, depending upon their age, gender, mobile device, mobile phone usage, mobile game experiences, and preferred games genres. Applying Factor analysis, we have identified Escape, Social interaction, Challenge and Competition, Fantasy, Diversion and Relaxation, Ease of Accessibility as key motivators for playing mobile games. Additional cluster analysis shows that the categorization of gamers, according to their usage habits and the key motivators for playing, can be made as follows: Multi-gamers, Communication-focused gamers and Mobile active-gamers. Further correlation of these grouping with socio-economic data shows the significant differences in gaming habits and patterns of mobile phone use.

• Health Policy and Management
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• v.24 no.1
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• pp.56-70
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• 2014

Background: Korea shows rapid population aging and increase in healthcare service use and expenditure. Also, this would be accelerated because of the baby boomers who will be 65 years old and more in 2020. Chronic disease is another reason that increases the use of healthcare service and expenditure of the middle- and old-aged households. Catastrophic health expenditure (CHE) is the index which can indicate the households' burden of health spending. Despite the importance, there are few studies on CHE of middle- and old-aged households and especially no panel study yet. This is the reason that this study is carried out. Methods: This study used 3-year data from the Korea Welfare Panel Study conducted from 2009 to 2011. We defined CHE if a household's health expenditure is equal or greater than the threshold value if income remaining after subsistence needs has been met. We used 4 different threshold values which are 10%, 20%, 30%, and 40%. In order to look at the households which experienced CHE, we conducted panel logit analysis after correspondence analysis and conditional transition probability analysis. Results: This study showed three notable results. First, there has been a difference among age groups, which implies that the older people are, the more easily they can experience CHE. Second, the households with no private insurance are shown to have a higher CHE occurrence rate. Lastly, there has been a significant difference among the kinds of chronic diseases. The households which have cancer, cerebrovascular disease, and heart disease have a higher CHE occurrence rate. However, the households with diabetes have no significant effects to CHE occurrence. Also, hypertension has a negative effect to the occurrence. Conclusion: With the results, it can be implied that elderly people with chronic disease are more needed in medical coverage and healthcare. Also, private insurance can play its role in protecting households from CHE. Therefore, it needs to conduct studies on CHE especially about different age groups, private insurance, and chronic disease.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.4
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• pp.2945-2950
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• 2015

While perfluoroalkane (PFA), a liquid state nucleating agent for a rigid polyurethane foam (RPUF) to enhance the thermal insulation property, has the excellent nucleating characteristics, it is very expensive as well as environmentally harmful due to the fluoride compound. Many researches, therefore, have been performed to develop the alternative nucleating agents to replace PFA. In the present work, a multi-wall carbon nanotube (MWCNT) was used as a sloid state nucleating agent, and thereby the effects on the property changes of the RPUF were carried out. Average cell size decreased from 165.6 for base RPUF to $162.9{\mu}m$ and cell uniformity was also enhanced, showing the standard cell-size deviation of 45.6 and 35.2, respectively. While k-factor of base PUF was $0.01763kcal/m.hr.^{\circ}C$, that of the sample with 0.01 phr MWCNT showed 1.02% reduced value of $0.01745kcal/m.hr.^{\circ}C$. Though the compressive yield stress is nearly the same as $0.030{\times}105Pa$ for the both samples, initial modulus of the sample with 0.01 phr MWCNT was higher than that of base sample. it was considered as the results that small amount of MWCNT could play a sufficient role as the effective nucleating agent for RPUF, showing that an echo-friendly RPUF with reduced-cost could be fabricated, which has an enhanced thermal and mechanical properties.

• Journal of the Korea Society for Simulation
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• v.22 no.3
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• pp.1-6
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• 2013

The ecosystem is the complex system consisting of various biotic and abiotic factors and the factors interact with each other in the hierarchical predator-prey relationship. Since the competitive relation spatiotemporally occurs, the initial state of population density and species distribution are likely to play an important role in the stability of the ecosystem. In the present study, we constructed a lattice model to simulate the three-trophic ecosystem (predatorprey- plant) and using the model, explored how the ecosystem stability is affected by the initial density. The size of lattice space was $L{\times}L$, (L=100) with periodic boundary condition. The initial density of the plant was arbitrarily set as the value of 0.2. The simulation result showed that predator and prey coexist when the density of predator is less than or equal to 0.4 and the density of prey is less than or equal to 0.5. On the other hand, when the predator density is more than or equal to 0.5 and the density of prey is more than or equal to 0.6, both of predator and prey were extinct. In addition, we found that the strong nonlinearity in the interaction between species was observed in the border area between the coexistence and extinction in the species density space.

• 한국벤처창업학회:학술대회논문집
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• 2018.11a
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• pp.201-213
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• 2018

This paper empirically analyzed whether or not professional college students' Protean career attitudes affect entrepreneurial intention through employability and entrepreneurship, and whether or not they have practical training experiences can make a difference in such influence. For this reason, a questionnaire survey was conducted on about 240 students at specialized universities in Seoul and the Gyeonggi province for one month beginning on June 1, 2018. Of the 220 collected questionnaires, 214 parts in total were selected for final analysis, except for the 6 parts of the answer sheet which were not sure if there was a missing value or not. The main findings are as follows. First, it has been confirmed that the professional career attitude of Protean has influenced employability and entrepreneurial intention, but has not directly influenced entrepreneurial intention. Secondly, it has been confirmed that the employability and entrepreneurship have have a positive influence on the entrepreneurial intention. Thirdly, it has been confirmed that employability and entrepreneurship play a role as a fully mediated role in the relationship between the attitude of the Protean career and the entrepreneurial intention. Fourthly, considering the characteristics of the vocational college, there is no difference in the influence of employability and entrepreneurship on the entrepreneurial intentions, but the influence of the protean career attitude on employability and entrepreneuriship was different depending on whether or not they had the practical training experiences. This study is to analyze the relationship between the protean career attitude and the entrepreneurial intention in the aspect of employment and entrepreneurial activation of young people.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.3
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• pp.568-578
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• 2021

Patents that are research results from industry-university cooperation (IUC) are a source of innovation, and play an important role in economic growth, such as technology transfer and commercialization. For this reason, there are many efforts to revitalize IUC, but in general, company patents are achievements that can be commercialized, rather than research achievements, so not all patents are used for business, even after their creation as the outcome of IUC. Therefore, this research supports the design of measures in which IUC can ultimately be linked to successful utilization of patents by identifying the purposes of IUC, even after it has been successfully promoted, and patents have been filed as a result. To this end, first, the patents registered for industry-academia cooperation in the United States are collected, and second, a predictive model is designed, with unexpired and expired patents predicted using machine learning techniques. The final identified patents are intended to derive available factors in terms of marketability and technicality. This study is expected to help predict the utilization of unexpired and expired patents, and is expected to contribute to setting goals for research results from technical cooperation between corporate and university officials planning early IUC.

• Journal of Digital Convergence
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• v.20 no.2
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• pp.77-90
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• 2022

The recent introduction of working from home due to COVID-19 has created a situation where it is difficult for organizational leaders to face their members in person, making it difficult for leadership in the general meaning to exert influence on subordinates. In this situation, this study attempted to suggest a self-leadership in which members of the organization motivate themselves and lead themselves as an alternative. In particular, this study attempted to confirm that self-leadership can be useful to MZ generation. In order to verify the effectiveness of self-leadership, job engagement was used as a dependent variable, and the mediation effect of loneliness was verified to determine how members' self-leadership affects their job engagement. In addition, it was confirmed how the self-leadership of members affects loneliness differently depending on the situational factors of overall justice. This study suggests that self-leadership can play a positive role in the current COVID-19 situation and generation MZ, and that the value of justice should be considered more important in each organization.

• Journal of Korean Tunnelling and Underground Space Association
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• v.11 no.1
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• pp.47-56
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• 2009

Rock bolts and shotcrete play a crucial role as a main support system in the underground space. Thus, the safety of the underground space may be affected by the defect of rock bolts. In order to evaluate the rock bolt integrity by using non-destructive technique, the transmission method of the guided ultrasonic waves, which are generated by using the piezo disk elements has been successfully performed. The energy generated by the piezo disk elements, however, is not enough for the rock bolts in the field. In addition, the piezo disk elements should be installed at the end of the steel bar during construction of the rock bolts. The purpose of this study is the devolvement of the reflection method, which may generate enough energy, and the application in the field rock bolts. Both laboratory and field tests are carried out. The guided ultrasonic waves with high energy are generated by the hammer impact with the center punch, and the AE sensor is used to measure the reflected guided waves. The received guided waves are analyzed by the wavelet transform. The peak value of the wavelet transform produces the energy velocity, which is used for the evaluation of the rock bolt integrity. The energy velocity increases with an increase in the defect ratio in both laboratory and field rock bolts. This study demonstrates that the hammer-impact reflection method may be a suitable method for the evaluation of the rock bolt in the field.

• The Journal of the Korea Contents Association
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• v.14 no.4
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• pp.355-367
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• 2014

The purpose of this research is to find the specific structure with factors that affect online game users' positive word of mouth(WOM) for online game companies to maintain existing and new users. In previous studies the influence of characteristics of online games and attributes of users on intention to play online games is mainly focused on. However online games are products with communication on network, so that critical mass through diffusion as well as the use of product by individual consumers is important issues. Therefore, it is necessary to consider network externality effect that the more value can be obtained by more game users. The authors verified that the influence of the variables like social mass and critical mass, affecting consumers' attitude and WOM. According to the research results, social norm and critical mass have significant influence on positive attitude and WOM intention for online games. Another results verified that social norm and users' attitude affect positive WOM intention directly. These results suggest managerial implication regarding social norm and critical mass to online game companies that desire for WOM to get more online game users.

• Journal of the Korean Data and Information Science Society
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• v.26 no.3
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• pp.619-630
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• 2015

The purpose of this study is to provide basic information to develop a game strategy plan of a team in a future by identifying the patterns of attack and pass of national men's professional volleyball teams and extracting core key words related with volleyball game performance to evaluate game performance using 'social network analysis' and 'text mining'. As for the analysis result of 'social network analysis' with the whole data, group '0' (6 players) and group '1' (11 players) were partitioned. A point of view the degree centrality and betweenness centrality in 'social network analysis' results, we can know that the group '1' more active game performance than the group '0'. The significant result for two group (win and loss) obtained by 'text mining' according to two groups ('0' and '1') obtained by 'social network analysis' showed significant difference (p-value: 0.001). As for clustering of each network, group '0' had the tendency to score points through set player D and E. In group '1', the player K had the tendency to fail if he attack through 'dig'; players C and D have a good performance through 'set' play.