• Convergence Security Journal
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• v.14 no.7
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• pp.29-36
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• 2014

In this study, we design and develop a VLC test-bed system which has been recently issued and focused as good convergence technology in the world. We classify the developed system into transmission part including analog LED driver module, digital signal modulation module, and receiver part with light sensing module and signal demodulation module. Then we introduce important characteristics and components. We analyze some factors for each module. To validate the communication of the designed VLC system, we develop a VLC sender-receiver simulator which can control the dimming factor and flicker-free effect. From the developed system, we observed about 12Mbps of data transmission rate with 0.5m~1m of distance, without packet loss. We verified the real-time communication with multimedia streaming which can be considered as very high date rate. The developed system and technology will be useful for some converged data services like indoor positing, home appliances, and indoor parking system.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.16 no.5
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• pp.27-32
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• 2016

In general, IoT(Internet of things) designate the intelligence technologies and services which interact all necessity information between human and things, things and thing and things and systems with all things connecting through the internet based. The smart home in present of IoT environment fuses the daily supplies/equipment which needs to use for the private life with the internet of things that is the fruit of the converged business through all most private consumption related in vastly. The concept of smart home has been built around early 2000s due to the spread of high speed internet and advanced of smart electronics and internet, furthermore influencing by the enhancement of wireless network and smart devices, it is advanced as a smart home within the internet of things environment. Smart home service inside the house which most closely implemented with personal life is being developed and advanced in various forms. These developments may exert a positive effect, but if it does not resolve the security issues for the smart home service, then it may cause a big plague of privacy and personal life.

• Convergence Security Journal
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• v.13 no.4
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• pp.61-68
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• 2013

Compared to the past, the number of disabled people in Korea is continuing to increase. As for the scope of the disability, it is expanding as well since it now includes all types of illnesses, car accidents, complications resulting from aging, industrial accidents and others accidents. Attempts are made in terms of applying sports game method that grafts IT technology in order to ensure that the disabled people participate continually in sports. While casting away the notion of play which was the role of a game in the past, new roles and domains were developed. In fact, serious game genre is what leads this change. Because serious game is leading the game industry fast, centered on education, sports, fitness and medical use, its market value can be considered very significant since it can be both fund and effective as it targets the disabled who cannot enjoy sports easily in reality. Accordingly, this research seeks to present the direction for the application of serious game for the disabled people by analyzing the current situation pertaining to the integrated and converged cases applied to the field of sports for the disabled when it comes to the serious game that uses contents based on the IT technology.

• Proceedings of the KIEE Conference
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• 2000.07a
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• pp.99-101
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• 2000

Different optimization algorithms have been proposed to solve real and reactive power optimization problems. Most of all, linear programming techniques that employed a simplex method have been extensively used. But, the growth in the size of power systems demands faster and more reliable optimization techniques. An Interior Point(IP) mehod is based on an interior point approach to aim the solution trajectory toward the optimal point and is converged to the solution faster than the simplex method. This paper deals with the use of Successive Linear Programming(SLP) for the solution of the Security Constrained Economic Dispatch(SCED) problem. This problem is solved using the IP method. A comparison with simplex method shows that the interior point technique is reliable and faster than the simplex algorithm.

• Journal of Environmental Science International
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• v.27 no.7
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• pp.499-507
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• 2018

Agricultural meteorological information is an important resource that affects farmers' income, food security, and agricultural conditions. Thus, such data are used in various fields that are responsible for planning, enforcing, and evaluating agricultural policies. The meteorological information obtained from automatic weather observation systems operated by rural development agencies contains missing values owing to temporary mechanical or communication deficiencies. It is known that missing values lead to reduction in the reliability and validity of the model. In this study, the hierarchical Bayesian spatio-temporal model suggests replacements for missing values because the meteorological information includes spatio-temporal correlation. The prior distribution is very important in the Bayesian approach. However, we found a problem where the spatial decay parameter was not converged through the trace plot. A suitable spatial decay parameter, estimated on the bias of root-mean-square error (RMSE), which was determined to be the difference between the predicted and observed values. The latitude, longitude, and altitude were considered as covariates. The estimated spatial decay parameters were 0.041 and 0.039, for the spatio-temporal model with latitude and longitude and for latitude, longitude, and altitude, respectively. The posterior distributions were stable after the spatial decay parameter was fixed. root mean square error (RMSE), mean absolute error (MAE), mean absolute percentage error (MAPE), and bias were calculated for model validation. Finally, the missing values were generated using the independent Gaussian process model.

• ETRI Journal
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• v.40 no.6
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• pp.745-758
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• 2018

A wide range of studies in various disciplines has focused on the Internet of Things (IoT) and cyber-physical systems (CPS). However, it is necessary to summarize the current status and to establish future directions because each study has its own individual goals independent of the completion of all IoT applications. The absence of a comprehensive understanding of IoT and CPS has disrupted an efficient resource allocation. To assess changes in the knowledge structure and emerging technologies, this study explores the dynamic research trends in IoT by analyzing bibliographic data. We retrieved 54,237 keywords in 12,600 IoT studies from the Scopus database, and conducted keyword frequency, co-occurrence, and growth-rate analyses. The analysis results reveal how IoT technologies have been developed and how they are connected to each other. We also show that such technologies have diverged and converged simultaneously, and that the emerging keywords of trust, smart home, cloud, authentication, context-aware, and big data have been extracted. We also unveil that the CPS is directly involved in network, security, management, cloud, big data, system, industry, architecture, and the Internet.

• Management & Information Systems Review
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• v.35 no.2
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• pp.99-118
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• 2016

With the development of Internet and popularization of smartphones over recent years, social network services are experiencing rapid growth. On top of this, smartphone gaming market is showing a rapid growth and the use of mobile social games is on the significant rise. The occurrence of game data manipulation targeting these services and personal information leakage is highlighting the importance of social gaming security. This study is intended to propose development plans effective and efficient in social game services by figuring out factors putting effects on security dependent behavior of social game users in Korea and carrying out a practical study on the casual relationship between factors influencing security dependent behavior through recognized behavioral control and attitudes for privacy infringement of these factors. To do this, proposed was a study model in which the HBM(Health Belief Model) allowing the social game user to influence security dependent behavior was expanded and applied as a major variable. To verify the study model of this study practically, a survey was conducted among university students in Seoul-based K University and S University who had experienced using social game services. According to the study findings, firstly, the perceived seriousness turned out to provide positive influence to trust. But, the perceived seriousness turned out not to put positive effects on self-efficacy. Secondly, the perceived probability turned out not to put positive effects on self-efficacy and trust. Thirdly, the perceived gain turned out to put positive effects on self-efficacy and trust. Fourthly, the perceived disorder turned out not to put positive effects on self-efficacy and trust. Fifthly, self-efficacy turned out to put positive effects on trust. But, self-efficacy turned out not to put positive effects on security dependent behavior. Sixthly, trust turned out not to put positive effects on security dependent behavior. This study is intended to make a strategic proposal so that social game users can raise awareness of their level of security perception and security willingness through this.

• Journal of the Korea Convergence Society
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• v.8 no.3
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• pp.101-114
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• 2017

This is the study of descriptive research to look into influence factors about how married middle-aged male' job stress, job security, depression, family bond, subjective health status and social support have an effect on the quality life. We collected data by giving questionnaires to 149 middle-aged males between the ages of 40 to 49, living B & D metropolitan city and J city, and used the SPSS/WIN18.0 version to analyze. The correlated factors of quality of life included job stress(r=-.544, p<.001), depression(r=-748, p<.001), job security(r=.566, p<.001), subjective health status(r=.537, p<.001), family bond(r=.712, p<.001) and social support(r=.739, p<.001). Factors influencing quality of life are depression, social support, family bond, subjective health status, current employment period and regular exercise. Therefore, a good quality middle-aged life, it will be needed to lower the depression, expand the social support system, improve family bond and subjective health status, increase employment period.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.3
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• pp.1510-1532
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• 2017

In smart grid, privacy implications to individuals and their families are an important issue because of the fine-grained usage data collection. Wireless communications are utilized by many utility companies to obtain information. Network coding is exploited in smart grids, to enhance network performance in terms of throughput, delay, robustness, and energy consumption. However, random linear network coding introduces a new challenge for privacy preserving due to the encoding of data and updating of coefficients in forwarder nodes. We propose a distributed privacy preserving scheme for random linear network coding in smart grid that considers the converged flows character of the smart grid and exploits a homomorphic encryption function to decrease the complexities in the forwarder node. It offers a data confidentiality privacy preserving feature, which can efficiently thwart traffic analysis. The data of the packet is encrypted and the tag of the packet is encrypted by a homomorphic encryption function. The forwarder node random linearly codes the encrypted data and directly processes the cryptotext tags based on the homomorphism feature. Extensive security analysis and performance evaluations demonstrate the validity and efficiency of the proposed scheme.

• The Journal of Society for e-Business Studies
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• v.15 no.3
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• pp.63-83
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• 2010

IPTV(Internet Protocol Television) is an innovation technology to lead the new media age. Internet protocol television (IPTV) is a next generation television converged with the Internet which are delivered portal services such as information search, games, movies, home shopping and banking. Generally, service quality affects to adopt or use these technologies. Quality of experience (QoE) is more issue to be considered than service quality because of the technological restriction and limitation that IPTV is accessed by the Internet. The QoE is defined as the cognitive and experienced quality measured with users through an experiment and is conceptually related to service quality. The objective of this paper is to suggest a methodology to measure the QoE of IPTV using a user testing. We find significant factors affecting QoE of IPTV through an exploratory study and measure QoE scores. We found the nine factors of graphics, picture, accuracy, access method, quality of contents, usability, security, and performance important for QoE. The QoE scores of picture, graphics, and quality of contents gained over the average score, but the overall score for IPTV service providers was not high and the QoE needs to be improved.