• Journal of Korea Society of Digital Industry and Information Management
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• v.11 no.3
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• pp.159-177
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• 2015

As smart phones become more common nowadays, mobile instant messengers such as kakao talk and line are used as essential communication tools exchanging information between individuals. Also, the mobile instant messengers extend their use to business area beyond communication between individuals. This study is on how factors of mobile instant messenger such as perceived security, perceived privacy, perceived enjoyment and perceived interactivity affect business continual usage intention through perceived usefulness. The proposed model is based on Expectation-Confirmation Theory of Oliver and Technology Acceptance Mode of Bhattacherjee. For an analysis, 159 survey responses were collected from the office workers in Seoul and nearby cities, having experiences of mobile instant messengers. To validate the proposed research model, PLS analysis is performed with the valid 154 questionnaires. The path analysis results are as follows. First, perceived security has a positive effect on expectation-confirmation. Second, perceived enjoyment has a positive effect on perceived usefulness. Third, perceived interactivity has a positive effect on both perceived usefulness and expectation-confirmation. Fourth, perceived usefulness has a positive usefulness on satisfaction and continual usage intention of mobile instant messenger. Last, expectation-confirmation has a positive effect on perceived usefulness, and satisfaction has a positive effect on continual usage intention of mobile instant messenger. Since the mobile instant messenger may bring a pressure of work and a violation of privacy, it is necessary that the company provide a guideline for use of the mobile instant messenger and establish the in-house mobile instant messenger system.

• Journal of the Korea Convergence Society
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• v.10 no.8
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• pp.283-289
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• 2019

The purpose of this study was to classify the elementary school students to latent groups according to the type of mobile phone usage and to verify the relationship with mobile phone dependency. The latent profile analysis was conducted using the first grade panel data of the elementary school in the Korea Children 's Youth Panel in 2016. The results found 3 latent classes of mobile phone usage: family and friend concentration (Type1), family concentration low level (Type2) and essential (Type3). The results of multiple regression analysis for verifying the relationship between mobile phone use type and mobile phone dependency showed a significant effect. The Type 2 showed more dependency than the Type 1, and the Type 1 showed more dependency than the Type 3. These findings provided basis for the guideline of mobile phones use and for proper intervention to prevent mobile phone dependency for elementary school students.

• Journal of Digital Convergence
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• v.12 no.10
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• pp.299-308
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• 2014

Today, a number of users using smartphone is very rapidly increasing by development of smartphone performance and providing various services. Also, they are using it for enjoying various services(cloud service, game, banking service, mobile office, etc.). today's mobile security solution is simply to detect malicious code or stay on the level of mobile device management. In particular, the services which use sensitive information, such as certificate, corporation document, personal credit card number, need the technology which are prevented from hacking and leaking it. Recently, interest of these mobile security problems are increasing, as the damage cases been occurred. To solve the problem, there is various security research such as mobile virtualization, ARM trustzone, GlobalPlatform for mobile device. Therefore, in this paper, I suggested efficient method that uses the mobile virtualization techniques of certification, security policy and access control, password/key management, safe storage, etc. and Trustzone of ARM for preventing information leakage and hacking.

• The Journal of the Korea institute of electronic communication sciences
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• v.11 no.1
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• pp.113-118
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• 2016

This study found that there are problems in sending mails at the postal service reception desks and proposes a system which transmits address information to POSNET(the terminals at post office reception) without the use of an additional security system based on address information which is stored in the terminals of mobile phones. The system proposed transforms the information of users into two-dimensional barcode(QR code) of the POSNET and a number of address information is texturized and transmitted to the POSNET with the use of how to read QR code and LAN such as bluetooth. When the system proposed is connected to the postal reception system, it can create and output mail addresses for mobile computers automatically and contribute to better performance for the post office reception clerks and better economic results.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2011.05a
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• pp.277-280
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• 2011

After the concept of Cloud Computing was first introduced, IT industry had focused on it. The Cloud Computing market is increasing as many major coporations have been participating in it. Now, the possibility of Mobile Cloud Computing has rising. Needless to say, the growth of Mobile Cloud Computing is explosive. Mobile industry changes its operational system from FeaturePhone to SmartPhone which are based on iPhone or Android. The number of Smart phone users in Korea exceeds 10 millions. Through this study, we will examine sorts and acctual situations of available domestic and international Mobile Cloud Computing Services in SmartPhone. Also, we will investigate the problems of current Mobile Cloud Computing and present the solutions.

• YAKHAK HOEJI
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• v.60 no.3
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• pp.112-117
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• 2016

A liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated for the determination of caffeine in forensic aqueous sample. The centrifuged sample ($100{\mu}l$) was diluted 50-fold with distilled water. The diluted sample ($400{\mu}l$) was then diluted further with $200{\mu}l$ of 0.1% formic acid solution and $400{\mu}l$ of acetonitrile containing 500 ng of caffeine-(3-methyl-$^{13}C_3$) prior to LC-MS/MS analysis. The mobile phase was composed of 0.1% formic acid in distilled water (A) and acetonitrile (B). Chromatographic separation was performed by using a Zorbax SB-C18 ($100mm{\times}2.1mm$ i.d., $3.5{\mu}m$) column and caffeine was eluted within 1.1 min. Linear least-squares regression with a 1/x weighting factor was used to generate a calibration curve with the coefficients of determination ($r^2=0.9983$). The lower limit of quantification was $25ng/ml$ for the analyte. The process efficiency was 98.6~100.1%. Intra- and inter-day precisions were not more than 2.1% and 1.7%, while intra- and inter-day accuracies were ranged from -6.8 to 4.5%, respectively. The suitability of the method was examined by analyzing unknown forensic aqueous samples.

• The Journal of the Korea institute of electronic communication sciences
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• v.8 no.9
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• pp.1359-1364
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• 2013

After platform changed from PC-based internet to mobile, SNS became new interactive media which relaces face-to-face interaction. the SNS users have already begun to recognize SNS as daily necessity. SNS market has been subdivided. In other words, SNS has entered into a period of vertical SNS that focus on contents and specific target. Therefore, It is necessary to analyze users for SNS planners. For this reason, analyzing why office workers who have the most powerful purchasing power use SNS is meaningful for SNS planners. Therefore, in this study, we analyzed the reasons for using SNS of office workers by studying relationship among office workers' stress, social support, self-expression and the use of SNS. As a result, the use of SNS has a significantly positive correlation with social support and self-expression. The self-expression in the SNS is not associated with stress, but rather it is the characteristics of the office workers. However the social support in the SNS affects to stress.

• Journal of Digital Convergence
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• v.12 no.2
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• pp.277-283
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• 2014

Recently, various cloud service has been being provided on mobile devices as well as desktop pc and server computer. Also, Smartphone users are very rapidly increasing, and they are using it for enjoying various services(cloud service, game, banking service, mobile office, etc.). So, research to utilize resources on mobile device has been conducted. In this paper, We have suggested efficient method of cloud resource management by using information of available physical resources(CPU, memory, storage, etc.) between mobile devices, and information of physical resource in mobile device. Suggested technology is possible to guarantee real-time process and efficiently manage resources.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.20 no.6
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• pp.83-96
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• 2010

The rapid spread of smart phone in recent years changes not only personal life but also work environment of organizations. Moreover, smart phone provoke service combination between industries and transit the digital paradigm in our society because of the character that anyone can develop or use the application of smart phone. Under these circumstances, the government hastens the construction of mobile-government in order to improve national services and communication with people. However, since security threats on smart phone become more critical recently, we should hurry the counter measures against mobile threats or we will face obstacles to the activation of mobile-government. On this article, we suggest the methods of information security and the Mobile-government Information Security Management System(M-ISMS) on the smart phone use environment for building up the secure and convenient mobile system in the national institution.

• The Journal of Information Systems
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• v.23 no.1
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• pp.185-202
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• 2014

ERP, a typical enterprise application, helps companies to increase their productivity and to support their decision makings. ERP is composed of diverse functions that are optimized under PC environment, whereas the ERP applications on a mobile platform have many constraints such as a small screen, limited resolution, and computing power. Because all the functions of a ERP legacy system are not required for ERP on a mobile device, the core functions of the ERP system should be selected to increase system efficiency. In this study, two main methods were used; interviews and log analyses. The end users using a ERP system were interviewed for their perceptions, and log data analyses were made for the hitting number of specific ERP functions. The differences between the actual usage based on log data and users' cognitive preferences about ERP functions were analysed. Finally, the functional differences between users' perception and actual usage were suggested for some practical implications.