• Journal of the Institute of Electronics and Information Engineers
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• v.49 no.9
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• pp.215-224
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• 2012

Using password on system is easy to build and shorten the access time to authorize user, which is high in use for vary system that requires users' authorization. Many input device are able to perform the password system easily, such as PC, smart-phone, tablet PC, etc. Beside the high usability of password, physical attack occurs when user put their password on the device, known as Shoulder Surfing attack. It used to be formed in numbers, characters or mix of different kinds, but new kind of password arose. Exploiting image or making scenarios are those kinds which are able to reflect users' intentions. Not many estimation exists for new password, so there's need to be standard for those new password for highlighting usability and accessability. In this paper, we propose password system with simple image and switching key-board to test statistical method to estimate usability on the password.

• Journal of the HCI Society of Korea
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• v.10 no.1
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• pp.19-27
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• 2015

As the mobile content industry is growing, mobile health (m-health) market is expanding based on various contents. It has developed in the way of utilizing health contents through mobile device such as smart phone among young people. This study aims to examine the usage of m-health application and factors of continuous usage among students in Seoul National University. The result is expected to provide a foundation for future health promotion programs utilizing m-health. The study analyzes the difference of application usage tendency based on demographic characteristic and the continuous usage, and compared the level of knowledge, attitude, belief, and practice (KABP) of mobile health application. 28% of the total sample population uses the application continuously, and their KABP level was higher than that of users that stopped using. This study goes beyond the previous studies of service satisfaction and acceptance analysis on the marketing level, and is meaningful in that it has analyzed the m-health application usage from the public health point of view.

• Journal of Korean Clinical Health Science
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• v.2 no.2
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• pp.148-157
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• 2014

Purpose. This study compares and analyzes customer service on customer satisfaction and customer royalty on customer satisfaction targeting the customers visiting a hospital or a clinic which is franchised or not. And it aims at helping business rationalization for a medical institution. Methods. This paper conducts a survey and selects a sample of 670 customers except the missing value targeting the customers of 4 primary health care institutions and 4 bigger health care institutions in Seoul and Gyeonggi province. It conducts frequency analysis for the purpose of investigating the respondents' generic characteristic and factor of their medical institution selection, and factor analysis, reliability analysis and regression analysis for the hypothesis testing. Results. The first hypothesis testing result is significant in level of significance of 0.01. The second one is the same as the first one, but the dummy variable shows a negative regression coefficient(-0.479). The third one is significant in level of significance of 0.01, but the forth one is not significant. And the respondents prioritize website(Home page) and convenience in use of a hospital procedure for selecting a hospital or a clinic. Conclusions. The additional analysis finds that the franchised group has more satisfaction than none franchised group. But in case of their royalty, the average of franchised and none franchised groups are not significantly different. Therefore, the results of this paper reveal to support the results of the advanced researches.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.16 no.4
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• pp.752-758
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• 2012

SNS(Social Networking Services) is oneline service that enable users to construct human network through their relation on web, such as following relation, friend relation, and etc. Recently, owing to the advent of digital devices (smart phone, tablet PC) which embedded GPS some applications which provide services with spatial relevance and social relevance have been released. Such an online service is called LBSNS. It is required to use spatial filtering so as to build the LBSNS system that enable users to subscribe information of interesting area. For spatial filtering, user and tweet attaches location information which divide into static property presenting fixed area and dynamic property presenting user's area changed along the moving user. In the case of using a location information including dynamic property, Continuous query occurred from the moving user causes the problem in server. In this paper, we propose spatial filtering algorithm using Virtual Grid for reducing frequency of query, and conclude that frequency of query on using Virtual Grid is 93% decreased than frequency of query on not using Virtual Grid.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.9
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• pp.1903-1909
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• 2011

This paper presents the development of a core module for integrating data from vehicle by the convergence technology of mobile telematics and black-box. This emerging technology can be referred to as Black-box in Mobile (BIM). For the development of BIM, sensors and cameras were realized in a driving robot. Relevant hardware implementation was achieved to verify the functionality of BIM. The transmitted signal from the driving robot was confirmed in an Android-based portable device. Existing Black-boxes were mostly developed by major transportation companies and focused only on storing data. The proposed BIM offers not only data storage but also easy-to-use real-time monitoring while in motion. In addition, the vehicle can be monitored on parking through shock sensors. This development is considered commercially viable as it is achieved via software implementation.

• KIISE Transactions on Computing Practices
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• v.20 no.12
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• pp.688-693
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• 2014

With the advent of ubiquitous environments, the smart phone has come into wide use and the demand for various content increases. Thus, in order to efficiently utilize limited resources cognitive radio technology is regarded as a possible solution. Besides spectrum sensing or access schemes, the provision of VoIP traffic service for secondary users with limited spectrum resources is a very important issue. In this paper, a resource allocation and control system for VoIP QoS provision in cognitive radio networks is proposed. Firstly, as the system model, the time structure of the network is addressed and, according to the structure, a bandwidth broker is proposed. In addition, based on available bandwidth estimated by the bandwidth broker, a connection admission control for secondary users is developed. It is demonstrated that the provision of VoIP QoS is greatly affected by channel utilization, the number of channels, and the length of timeslot.

• The Journal of the Korea Contents Association
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• v.14 no.12
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• pp.565-573
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• 2014

We have various e-commerce like on-line banking, stock trading, shopping using a PC or SmartPhone. In e-commerce, two parties use the certificate for identification and non-repudiation but, the attack on the certificate user steadily has been increasing since 2005. The most of hacking is stealing the public certificate and private key files. After hacking, the stolen public certificate and private key file is used on e-commerce to fraud. Generally, the private key file is encrypted and saved only with the user's password, and an encrypted private key file can be used after decrypted with user password. If a password is exposed to hackers, hacker decrypt the encrypted private key file, and uses it. For this reason, the hacker attacks user equipment in a various way like installing Trojan's horse to take over the user's certificate and private key file. In this paper, I propose the management method to secure private key of PKI using One Time Password certification technique. As a result, even if the encrypted private key file is exposed outside, the user's private key is kept safely.

• The Journal of the Korea Contents Association
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• v.14 no.12
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• pp.950-958
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• 2014

According to the rapid spreading of smart phone, the use of social network service(SNS) is also increasing rapidly. Social network service(SNS) which plays an important role in customer relationship management and brand management is becoming more important. This study aims to find out if differences exist in the perceptions of service quality and the consumer behaviors between Korean and Chinese consumers using SNS. In order to achieve the objectives of the study, the literatures of service quality and consumer behavior theory is reviewed. And based on the literature reviews, dimensions related to service quality and consumer behavior are derived and T-test is used to identify the differences. According to the analysis, significant differences exist in the perceptions of service quality and consumer behaviors between Korean and Chinese consumers using SNS. The results not only provide theoretical evidences for further SNS study but also provide practical evidences for companies in their overseas expansion.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37B no.11
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• pp.975-983
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• 2012

Multi network interface has become common phenomenon for mobile devices such as smart phone which has 3G, LTE-advanced, WiFi. Consequently, there are researches for a transmission strategies using multiple paths below on end-to-end connection. MPTCP which is proposed and being standardized by the IETF as a new transport protocol can perform concurrent multipath transfer using multiple network interfaces. However, current MPTCP has performance degradation when it use heterogeneous networks which have quite different network characteristics. Therefore, this paper proposes the packet scheduling scheme and receiver-based recovery scheme to reduce the performance degradation due to reordering problem. Also, simulation results show that the proposed scheme can improve throughput and retransmission performance.

• The Journal of Korean Association of Computer Education
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• v.16 no.4
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• pp.23-31
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• 2013

The purpose of this study is to examine if educational programs to intervene with smartphone addiction developed for elementary school students are effective in reducing their smartphone overuse that has been rapidly increasing nowadays. To attain the goal, the study analyzes internet addiction intervention programs previously developed with the cognitive behavior therapy of which effectiveness has been verified in psychotherapy for those showing addiction, and based on that, it develops and applies educational programs to intervene with smartphone addiction. The conclusions the paper has drawn are as follows: First, educational programs to intervene with smartphone addiction are effective in reducing the tendencies of smartphone addiction of those students using smartphones too much for their irrational thinking or habitual behavior. Second, educational programs to intervene with smartphone addiction will facilitate behavioral changes regarding negative factors of smartphone addiction such as maladaptation in everyday life or tolerance and also help the reconstruction of elementary school students' positive cognition on smartphone use.