• Journal of Communications and Networks
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• v.8 no.2
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• pp.151-157
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• 2006

In a continuously expanding wireless world, the number of radio systems increases every day and efficient spectrum usage becomes a more significant requirement. Ultra-wideband (UWB) and cognitive radio are two exciting technologies that offer new approaches to the spectrum usage. The main objective of this paper is to shed the first light on the marriage of these two important approaches. The strength of orthogonal frequency division multiplexing (OFDM) based UWB in co-existing with licensed systems is investigated. The opportunity concept is defined, and the requirements of the opportunistic spectrum usage are explained. It is proposed to take the UWB-OFDM from the current underlay implementation, and evolve it to a combined underlay and opportunistic spectrum usage technology, leading to cognitive UWB-OFDM. This way, we aim at making UWB more competitive in the wireless market with extended range, higher capacity, better performance, and a wide variety of applications.

• Journal of the Architectural Institute of Korea Structure & Construction
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• v.34 no.7
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• pp.27-34
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• 2018

The energy consumption of apartment houses is affected by various factors. The criteria for assessing current energy usage are area, region and purpose. The purpose of this study is to obtain the reliability of the method of evaluating the existing energy consumption certificate and to derive usable evaluation factors according to the correlation of factors affecting energy consumption. The research process collects energy usage data for apartment houses in Daegu and calculates statistical results through correlation analysis and multiple regression analysis. As a result, it was found that the power energy is influenced by the yearly factor of physical characteristics, and the heat energy and total energy usage are influenced by the energy source which is energy characteristic factor.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.4
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• pp.1489-1503
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• 2018

Spectrum reuse has attracted much concern of researchers and scientists, however, the dynamic spectrum access is challenging, since an individual secondary user usually just has limited sensing abilities. One key insight is that spectrum usage forecasting among secondary users, this inspiration enables users to obtain more informed spectrum opportunities. Therefore, spectrum usage forecasting is vital to cognitive radio networks (CRNs). With this insight, a spectrum usage forecasting model for the occurrence of primary users prediction is derived in this paper. The proposed model is based on auto regressive enhanced primary user emergence reasoning (AR-PUER), which combines linear prediction and primary user emergence reasoning. Historical samples are selected to train the spectrum usage forecasting model in order to capture the current distinction pattern of primary users. The proposed scheme does not require the knowledge of signal or of noise power. To verify the performance of proposed spectrum usage forecasting model, we apply it to the data during the past two months, and then compare it with some other sensing techniques. The simulation results demonstrate that the spectrum usage forecasting model is effective and generates the most accurate prediction of primary users occasion in several cases.

• Journal of Korea Technology Innovation Society
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• v.13 no.4
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• pp.772-793
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• 2010

In this paper, author estimated economic scale of radiation usage in Korea using Input-Output table 2005 and other micro data published. This estimation focused all kind of radiation usage in whole economic activity. Estimation of economic scale is quantitative analysis for how much radiation usage increase productivity and welfare. Economic scale estimation of radiation usage in Korea 2005 is 6,297 Billion Won and it occupies 0.74% of GDP. It is smaller level compared with that of US and Japan. It is 1.5% of GDP in US (1997) and 1.2% of GDP in Japan (2005). Radiation usage in industrial sector is 5,775 Billion Won and it is 0.68% of GDP. Radiation usage in agriculture sector is 171 Billion Won and it is 0.02% of GDP. Radiation usage in medical sector is 351 Billion Won and it is 0.04% of GDP. This implied that radiation usage in industrial sector is larger than other sector. Use of medical radiology may be enlarge in the future due to population structure. The result that radiation usage occupied 0.74% of GDP arouse contribution of radiation usage in daily life. It helps people to have more understanding and public acceptance for radiation.

• Journal of Information Technology Services
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• v.14 no.2
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• pp.1-14
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• 2015

As mobile distribution environment is changing rapidly and competition is more intensive in businesses today, technology based self service have been changed and developed. Among the change, financial institutes and consumers are interested in mobile banking services. This study attempted to investigate the impact of service convenience value on customer satisfaction and re-usage intention, and investigated the moderate effect of technology anxiety in the relationship between service convenience value and mobile banking service usage. For this study, data were gathered from respondents who have experience using mobile banking service and analyzed by structural equation model. A convenience value affected consumer satisfaction and re-usage intention toward mobile banking service. Also, this study found that the more technology anxiety, the less re-usage intention. The results show that management and investment to improve convenience value and to reduce technology anxiety make consumers' satisfaction and re-usage intention toward mobile banking service.

• English Language & Literature Teaching
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• v.16 no.3
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• pp.101-117
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• 2010

This study examines whether English users at a U.S. university apply avoidance strategy in using English articles. All participants had learned English for at least 10 years and had used English for at least 15 years at the time of the data collection, so they made an ideal sample to examine the differences between native speakers of English and non-native speakers of English, in terms of avoidance strategy usage of English articles. To examine whether non-native speakers avoid using a certain feature when unsure of the correct usage, the mean differences of each article usage between NS and NNS groups were calculated and compared. On the basis of results showing that there are no statistically significant differences in terms of article usage between the groups, it is concluded that the highly advanced level participants did not use avoidance strategy in English articles, and that the type of English article and the task type did not affect learners' avoidance strategy usage. This research is expected to provide teachers and researchers with information about highly advanced level L2 language speakers' usage patterns with regards to avoidance strategy.

• Proceedings of the Korea Information Processing Society Conference
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• 2014.11a
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• pp.1136-1138
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• 2014

Recently, predicting personality with the help of smartphone usage is become very interesting and attention grabbing topic in the field of research. At present there are some approaches towards detecting a user's personality which uses the smartphones usage data, such as call detail records (CDRs), the usage of short message services (SMSs) and the usage of social networking services application. In this paper, we focus on the predicting user attitude based on MBTI theory by using their smartphone usage data. We used Naïve Bayes and SVM classifier for classifying user personalities by extracting some features from smartphone usage data. From analysis it is observed that, SVM classifier works well as compared to Naïve Bayes.

• Journal of Internet Computing and Services
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• v.21 no.4
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• pp.77-85
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• 2020

The purpose of this study is to explore the changing trajectory of using educational media through longitudinal data analysis. We categorize the feature of using educational media as usage for learning, usage for information, and usage for the game. We explore the longitudinal changing patterns of usage for learning, usage for information, and usage for the game by LGM(Longitudinal Growth Modeling). We also find the gender difference between these longitudinal changing trajectories. We used 3,499 samples of KYPS middle school second-grade panel data. We found these results: (a) Both usage for learning and information are statically significant variability in initial level and rate of change. Both of the changing trajectories have increased. (b) Girls have a higher rate of the change both in the usage of learning and information than boys over time. (c) There is a statistically significant individual variability in initial levels and rate of change in the usage of the game over time. (d) Boys have a higher rate of initial value than girls in the usage of games, but there is no significant difference in the rate of changing trajectories.

• Journal of Information Technology Services
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• v.6 no.3
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• pp.1-26
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• 2007

In this paper, we identified factors that affect the usage of UCC, which is becoming increasingly popular in our society and throughout the globe. Four hypotheses were tested using a new integrative model of UCC usage, which is built up by incorporating the TAM and the PA(pleasure-arousal)model. We analyzed the data collected in our survey of 258 individual UCC users during the period from Oct 2006 to Dec 2006. We found that pleasure and arousal showed a strong significant effect on individual's UCC usage, supporting the findings of the exiting research on TAM. To be specific, arousal had an effect on the UCC usage through its effect on pleasure and self efficacy. Pleasure affected the UCC usage in two ways: First, pleasure affected UCC usage through increasing the ease of UCC service. At the same time, pleasure had a direct effect on the UCC usage. Contrary to what the prior research on technology acceptance suggested, we found ease of use and social influence had no significant effect on individual’s UCC usage. We suggest that this finding of no effect of ease of use and social influence has an important implication in understanding the UCC usage. That is, the UCC usage may be motivated by different factors than those which inspire other technology acceptance behavior. The UCC users may be engaging in a creative activity enjoying the sheer pleasure of creating UCC, self expression, and sharing what they want to tell. Intrinsic motivation rather than extrinsic motivation seems to click this new type of technology users.

• 한국경영정보학회:학술대회논문집
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• 2007.06a
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• pp.80-86
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• 2007

In this paper, we identified factors that affect the usage of UCC, which is becoming increasingly popular in our society and throughout the globe. Four hypotheses were tested using a new integrative model of UCC usage, which is built up by incorporating the TAM and the PAD(pleasure-arousal-dominace)model. We analyzed the data collected in our survey of 258 individual UCC users during the period from Oct 2006 to Dec 2006. We found that pleasure and arousal showed a strong significant effect on individual's UCC usage, supporting the findings of the exiting research on TAM. To be specific, arousal had an effect on the UCC usage through its effect on pleasure and self efficacy. Pleasure affected the UCC usage in two ways: First, pleasure affected UCC usage through increasing the ease of UCC service. At the same time, pleasure had a direct effect on the UCC usage. Contrary to what the prior research on technology acceptance suggested, we found ease of use and social influence had no significant effect on individual's UCC usage. We further found that such effects of the ease of use and pleasure factors are more positive in the entertainment-based UCC than in the relationship-based UCC.