• KSII Transactions on Internet and Information Systems (TIIS)
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• v.14 no.3
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• pp.1313-1336
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• 2020

Cognitive radio (CR) is regarded as an effective approach to avoid the inefficient use of spectrum. However, CRNs have more special security problems compared with the traditional wireless communication systems due to its open and dynamic characteristics. Primary user emulation attack (PUEA) is a common method which can hinder secondary users (SUs) from accessing the spectrum by transmitting signals who has the similar characteristics of the primary users' (PUs) signals, and then the SUs' quality of service (QoS) cannot be guaranteed. To handle this issue, we first design a multiple-phase energy detection scheme based on the cooperation of multiple SUs to detect the PUEA more precisely. Second, a joint SUs scheduling and power allocation scheme is proposed to maximize the weighted effective capacity of multiple SUs with a constraint of the average interference to the PU. The simulation results show that the proposed method can effectively improve the effective capacity of the secondary users compared with the traditional overlay scheme which cannot be aware of the existence of PUEA. Also the good delay QoS guarantee for the secondary users is provided.

• The Journal of Information Systems
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• v.29 no.1
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• pp.267-287
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• 2020

Purpose Online platform companies can increase the spread of content by communicating with users who have diverse preferences through social networks. Previous studies show the mixed effect on the network overlap, and there was a limited examinations for the underlying mechanism. This study expects high academic and practical implications that can be provided by studying on the user's viewership network. The purpose of this research is to examine the effects of network overlap on the users' viewership for creators of user-generated content in YouTube. We explain the direct and in-direct effects through the content sharing and the valence of user ratings. Design/methodology/approach The data contains 45 channels and 4,085 video clips from YouTube. We control the effect of the categories, channel characteristics, and vide clip characteristics on the viewership. PROCESS macro were used to analyze the direct and in-direct effects of network overlap. Findings The analysis results showed that the network overlap directly affect on the users' viewership. The variable decreases the moderators (i.e., content sharing and the valence of user ratings). This result implies that the users can not satisfy their need for uniqueness which is achieved by content sharing and rating in the overlapped network.

• Journal of the Korean Home Economics Association
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• v.43 no.11 s.213
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• pp.197-210
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• 2005

The purposes of this study were to examine: (1) the extent to which school-age children used computer games; (2) whether there were differences between children who played computer games to a greater extent and children who played computer games to a normal extent in their levels of depression, anxiety, self-esteem, and social anxiety; and (3) whether children's social withdrawal, aggression, and mothers' psychological control explained the extent of children's computer game playing. The subject were 270 children in the 6th grade. It was found that $55.6\%$ of the children were normal users, $39.3\%$ of the children were somewhat heavy users, and $5.2\%$ of the children were heavy users of computer games. There was a gender difference in the proportions of heavy computer game playing. That is, there were more heavy users among boys than among girls. It was also found that social withdrawal, aggression, and mothers' psychological control were significant predictors of the extent of children's computer game playing. That is, the levels of children's social withdrawal, aggression, and their perceptions of mothers' psychological control predicted the degree to which children played computer games.

• Journal of Auto-vehicle Safety Association
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• v.10 no.4
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• pp.54-59
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• 2018

While the advanced trffic environment systems are developed recently, the traffic systems for transportation vulnerable are still under development and their social life are limited as well. In order to the secure their mobility rights, it had been required to set up the particular system for the traffic welfare. One of the significant items is the express bus operation for wheelchair users. Thus, the research of development and operation for express buses with wheelchair users was funded by the Korean government. Before the express bus development for wheelchair users based on the current bus model, this study set up the evaluation method for the bus rollover characteristics to ensure occupant safety using the finite element method. The partial bus model was developed corresponding to the full bus model response under rollover event and the evaluation method based on two model (full bus model and partial bus model) responses is planned to apply the model development of express bus modification for wheelchair users.

• Journal of Korean Academy of Nursing
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• v.53 no.2
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• pp.155-166
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• 2023

Purpose: Although heated tobacco product (HTP) use among adolescents is an emerging public health problem, little is known about the frequency and quantity of HTP use. Thus, we investigated the associations between the frequency and quantity of HTP use and smoking characteristics (i.e., combustible cigarette [CC] and electronic cigarette [EC] use, and attempts to quit smoking) among CC-smoking adolescents. Methods: We analyzed nationally representative data from 2,470 Korean adolescents who were current CC smokers. To investigate our aim, we conducted multinomial logistic and logistic regression analyses. Results: We found that daily and heavier CC users had greater likelihoods of more frequent and heavier HTP use. In addition, dual users of CCs and ECs were more likely to use HTPs more frequently and heavily than CC users who did not use ECs. Moreover, daily EC users had the highest risk of frequent and heavy HTP use. The frequency and quantity of HTP use were not associated with attempts to quit smoking. Compared to CC-only use, dual use of CCs and HTPs was not associated with quitting attempts, and triple use of CCs, ECs, and HTPs was associated with a lower likelihood of quitting attempts. Conclusion: HTP use was less likely to displace CC use and promote attempts to quit smoking. Thus, strict regulations are required to prevent the promotion of HTPs as a substitute for CCs or as a means of quitting smoking. Additionally, health professionals should consider preventive interventions for HTP, as well as CC and EC use among adolescents.

• Journal of the Korean Society of Clothing and Textiles
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• v.47 no.5
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• pp.873-890
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• 2023

This study analyzed users' emotional responses to VI character design through YouTube comments. The researchers applied text-mining to analyze 116,375 comments, focusing on terms related to character design and characteristics of VI. Using the BERT model in sentiment analysis, we classified comments into extremely negative, negative, neutral, positive, or extremely positive sentiments. Next, we conducted a co-occurrence frequency analysis on comments with extremely negative and extremely positive responses to examine the semantic relationships between character design and emotional characteristic terms. We also performed a content analysis of comments about Miquela and Shudu to analyze the perception differences regarding the two character designs. The results indicate that form elements (e.g., voice, face, and skin) and behavioral elements (e.g., speaking, interviewing, and reacting) are vital in eliciting users' emotional responses. Notably, in the negative responses, users focused on the humanization aspect of voice and the authenticity aspect of behavior in speaking, interviewing, and reacting. Furthermore, we found differences in the character design elements and characteristics that users expect based on the VI's field of activity. As a result, this study suggests applications to character design to accommodate these variations.

• Journal of Distribution Science
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• v.12 no.7
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• pp.103-110
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• 2014

Purpose - This study attempts to examine the new concept of mobile internet users' lifestyles through empirical analyses based on the i-VALS concept study that had classified the VALS program, among others, aiming at internet users. Research design, data, and methodology - A total of 300 questionnaire copies were distributed, of which 273 were collected; only 244 were used for the empirical study after excluding some inappropriate or unusable ones. To analyze the data collected, the SPSS/WIN 19.0 statistical package was used, and the lifestyles of mobile internet users were reclassified after analyzing the reliability and validity of the responses. Results - The study involved the empirical analyses of the new concept of the mobile internet users' lifestyles based on the i-VALS concept study, of which the subjects were internet users. Conclusion - It is possible to provide enterprises with more systematic and objective fundamental data based on the characteristics of mobile internet users' lifestyles, to help enterprises with their establishment of market segmentation strategies for promoting mobile shopping in the future.

• Asia pacific journal of information systems
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• v.20 no.4
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• pp.125-147
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• 2010

This paper Introduces an electronic auction service to be provided on Interactive TV (T-auction). This converged service is expected to much enhance the quality of the service to current online auction users through vivid visualization and live Interactive experience. Our study focuses on how the characteristics of the interactive TV-based shopping platform can affect users' attitudes towards the converged service. To develop our proposed research model, we extended the technology acceptance model and integrated it with a hedonic factor, or perceived enjoyment to reflect the dual characteristics of the converged system. We also adopted the variable of intermediary trust In the service as a critical mediating determinant for a successful commutations-mediated commerce. The research model was verified with an empirical study conducted on 970 Korean online auction users. Results show that both trust and perceived usefulness positively affect user adoption of the service. Trust had not only a direct effect on users' attitudes toward T-auction but also an indirect one by mediating the service quality, information quality, perceived enjoyment and ease of use. Meanwhile, the hedonic factor of T-auction contributes to increasing both the level of the intermediary's trust and its perceived usefulness. Users' enjoyment also was found to help form a positive attitude toward T-auction services. Theoretical and practical implications of this study for current e-auction service providers and potential t-auction service providers are also discussed.

• Journal of Nutrition and Health
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• v.43 no.3
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• pp.294-303
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• 2010

Various types of health functional foods (HFF) are popularly used among middle-aged. We surveyed 946 middle-aged in Korea for HFF use and significant variables for their HFF use including demographic characteristics, health related variables and nutritional beliefs. The use prevalence of HFF was 58.9%, and among all types of HFF, red ginseng products were taken most frequently, followed by nutritional supplements, ginseng products > mushroom products. HFF was taken more frequently in subjects from high monthly family income (p < .001), and in those from families with a high socioeconomic status (p < .001) in comparison to each corresponding group. Mean age of users was higher than nonusers (p < .001). Self concern about health (p < .001) and usage ratio of HFF by family (p < .001) were higher in users than in nonusers of HFF. Total dietary assessment score was not different in two groups, and users had a more positive view concerning the potential health benefit of HFF than nonusers (p < .001). Most users of HFF took HFF when they were healthy (52.8%) and experienced a little effect through the HFF use (51.2%). Most users of HFF obtained the information on HFF through family and relatives (30.5%) and most of them purchased HFF at pharmacy or oriental medicine clinics (44.5%). HFF users preferred multivitamin and Ca-supplements most among the vitamin mineral supplements belonged to HFF. Given the widespread use of HFF and inappropriate usage of HFF among subjects, the proper use of these products for the contribution to their optimal nutrition and overall health is a subject that should be formed through practical nutrition education considering the various variables affecting their HFF use.

• Culinary science and hospitality research
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• v.23 no.7
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• pp.97-111
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• 2017

As a single-person household emerges as an important consumer group, an Online-to-Offline or Offlineto-Online(O2O) service market is rapidly growing. This study attempted to verify the effects of convenience and webrooming characteristics of O2O service using the Technology Acceptance Model (TAM). The purpose of this study was to investigate the effects of the convenience and webrooming of food O2O service on users' perceived ease of use and perceived usefulness, and the effects of perceived ease of use and perceived usefulness on purchase intention of O2O services. Using a convenience sampling technique, an online survey was conducted through Google survey from April 16 to April 30, 2017 and was distributed to 447 O2O service users. A total of 320 questionnaires were included in the final analysis. The results showed that convenience had a significant effect on users' perceived ease of use as well as perceived usefulness. In addition, users' perceived ease of use had a significant impact on users' perceived usefulness. Finally, both perceived ease of use and perceived usefulness positively affected users' purchase intention of O2O services. These findings suggest that differentiated events, promotions, and store information should be provided when launching O2O service because webrooming is a more important factor in enhancing perceived usefulness than the perceived ease of use.