• Journal of the Korean Society of School Health
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• v.28 no.3
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• pp.200-210
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• 2015

Purpose: This study aimed to examine the use of smart phones and their relationship with self-efficacy and academic achievement among students in 5th to 6th grade. Methods: 954 students in $5^{th}$ to $6^{th}$ grade were selected from three elementary schools in K City through purposive sampling. Data of 591 respondents were analyzed by $x^2$ test, ANOVA, correlation analysis and multiple regression analysis using the SPSS/WIN program. Results: First, 64% of the students possessed a smart phone and female students used their phone more than male students. 47.5% of the students said they first used a smartphone in their $5^{th}$ grade and 11.7% said in their 6th grade. Second, heavier use of smart phones was related to a lower level of self-efficacy (p<.001). Third, the more the students used a smart phone, the less they achieved in academic performance (Korean language: p<.001, mathematics: p<.01). Finally, the biggest factor influencing smart phone addiction was longer use of smart phones. In addition, lower self-efficacy and lower ability to adapt to difficult tasks were the factors influencing the increase in smart phone addiction. Less use of smart phones and higher self-efficacy resulted in higher achievement in academic performance. Conclusion: It is essential to decrease students' use of smart phones and improve their self-efficacy and academic performance. Intervention programs to reduce the use of smart phones should include a profound interest, a personality-oriented educational environment and sufficient dialogues with students at home, schools and the local society, beyond simple regulations to prevent adverse effects.

• Journal of the Korea Society of Computer and Information
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• v.27 no.11
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• pp.157-163
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• 2022

In this paper, we propose to develop a Bluetooth Health Device Profile (HDP)-based smartphone system to utilize it for early detection of urinary tracts diseases that occur a lot in cats. Therefore, based on Bluetooth HDP, we developed a device and mobile application system (Mycatner®) that can monitor cat activity, toilet usage, urinary disease, and health status, and evaluated its availability to monitor cat health status. The specific feature of this system is that it can measure the number of cat urination frequencies to identify abnormal conditions suspected of urinary tract diseases early, and second, it can be tested with urine test paper and shared with animal hospitals, reducing time and cost. As a result, it is evaluated that the developed device capable of wireless monitoring the urinary system health status of cats is the first in our knowledge.

• KIPS Transactions on Computer and Communication Systems
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• v.4 no.8
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• pp.253-258
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• 2015

From the point of view of u-healthcare, heart rate is so useful for both illness for taking care of patients and wellness for improving the level of health and wellbeing. It is because heart rate is a significant clinical variable for all kinds of diseases as well as an indicator of the intensity of exercise. Recently, a number of various wearable heart rate monitors have been released to check people's status in the body by monitoring their heart rates. In addition, a number of smartphone applications have been released to conveniently monitor the status of exercise by using heart rate monitors. However, all of these applications are limited to a personal usage. In this paper, we will design a system to simultaneously monitor heart rates coming from multiple users in a real-time, and develop an Android application to apply the system. The application mainly features a simultaneous monitoring of heart rates coming from multiple users, allowing to be effectively applied to fitness centers.

• Journal of Agricultural Extension & Community Development
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• v.19 no.4
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• pp.833-857
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• 2012

This study was carried out aiming to provide information and enhance the satisfaction of real-time smartphones users on Rural Amenity Resources Information Services. For this purpose, domestic and international discussions and surveys on technology developments and expert analysis smartphone technology were reviewed. And empirical data were collected from 600 people through structured questionnaires including smart-phone experience, smartphone usage behavior, the required content, service items, service quality, Through this information, the content of rural amenity resources, how to take advantage of smart phones. Service Plan and developed, and a rural village locations to target mobile phone technology, the content was established. Through the preference analysis of the collected data, we designed the contents of rural amenity resources information based on smart-phone. It will be helpful to enhance the interchange between urban and rural such as farmer's market and rural tourism.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.8 no.6
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• pp.2070-2086
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• 2014

As a kind of personal lifelog data, activity data have been considered as one of the most compelling information to understand the user's habits and to calibrate diagnoses. In this paper, we proposed a robust algorithm to sampling rates for human activity recognition, which identifies a user's activity using accelerations from a triaxial accelerometer in a smartphone. Although a high sampling rate is required for high accuracy, it is not desirable for actual smartphone usage, battery consumption, or storage occupancy. Activity recognitions with well-known algorithms, including MLP, C4.5, or SVM, suffer from a loss of accuracy when a sampling rate of accelerometers decreases. Thus, we start from particle swarm optimization (PSO), which has relatively better tolerance to declines in sampling rates, and we propose PSO with an adaptive boundary correction (ABC) approach. PSO with ABC is tolerant of various sampling rate in that it identifies all data by adjusting the classification boundaries of each activity. The experimental results show that PSO with ABC has better tolerance to changes of sampling rates of an accelerometer than PSO without ABC and other methods. In particular, PSO with ABC is 6%, 25%, and 35% better than PSO without ABC for sitting, standing, and walking, respectively, at a sampling period of 32 seconds. PSO with ABC is the only algorithm that guarantees at least 80% accuracy for every activity at a sampling period of smaller than or equal to 8 seconds.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.27 no.6
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• pp.1347-1359
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• 2017

SQLite database is a file-based DBMS(Database Management System) that provides transactions, and it is loaded on smartphone because it is appropriate for lightweight platform. AS the usage of smartphone increased, SQLite-related crimes can occur. In this paper, we proposed a new concealing method for SQLite db file and a detection method against it. As a result of concealing experiments, it is possible to intentionally conceal 70bytes in the DB file header and conceal original data by inserting artificial pages. But it can be detected by parsing 70bytes based on SQLite structure or using the number of record and index. After that, we proposed detection algorithm for concealed data.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.7
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• pp.3238-3246
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• 2013

The progress of Information Technology enables people can communicate each others using the Internet. As a smartphone proliferates, many free mobile VoIP(Voice over IP) application are developed and accepted by smartphone users. In this study we investigate the factors affecting the acceptance of mobile VoIP applications and the structural relationship among these factors. We review the related works and extract the related factors and build a research model describing the causal relationship among these factors. We conduct an empirical study - a survey and statistical analysis - to verify the research model. EFA(Exploratory Factor Analysis) is applied for variables in the survey and SEM(Structural Equation Model) is used to reveal the structural relationship among the factors. We can find that two factors - usefulness of mobile VoIP and social influence - positively affect usage intention and actual use. These findings imply that it is required to emphasize the benefits of mobile VoIP use and add S/W functionalities enhancing social influence.

• The KIPS Transactions:PartD
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• v.19D no.4
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• pp.281-292
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• 2012

A wide variety of smartphone applications is increasing the usage time of smartphone. Due to the increased time, it becomes difficult to providing stable services to users with limited battery capacity. The past works have been performed the power management of mobile device toward long-lasting battery development or low-power electric devices. However as the complexity of software embedded into system are increased, the research interests of the software power analysis is also increased. Among these studies on the software power analysis, model-based analysis technique is one of major interests because it can be able to analyze the power consumption before the development of source codes, then the analysis result can be used in the development of the software system, This paper suggests a model-based power analysis technique using UML state machine diagram. Our proposed technique estimates the power consumption by the simulation of Perti-net which is transformed from the state machine diagram.

• Journal of Intelligence and Information Systems
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• v.17 no.4
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• pp.193-212
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• 2011

Mobile instant messaging service is surfacing to an important keyword in the mobile market together with popularization of Smart phones. Mobile instant messaging service in Korea has become popular to the degree of 87.9% usages from total Smartphone holders, and it is expected that using populations will be more enlarged afterwards if considering a fact that its populations of Smartphone is continuously being increased after exceeding 10 million persons (Trend Monitor, June 2011). In the instant messaging market where competitions have been deepened day by day, raising customer's royalties will be the key for company's business survivals and goals of corporate marketing strategies. It could be said that understanding on which factors affect to customer retentions and royalties is very important. Specially, as changing status is being progressed very quickly in case of innovative mobile services like the instant messaging service, research necessities on how many do consumers use the services after accepting them, how much do consumers use them variously, and whether does it connect to long-term relations have been increased, but studies on such matters are in insufficient situations actually. Therefore, this study examined on which effects were affected to use-diffusion and loyalty factors from perceived customer vales' factors having been occurred after accepting the mobile instant messaging service, namely 'functional value', 'monetary value', 'emotional value', and 'social value'. Also, the study looked into what kind of roles do the service usage and using variety play to service's continued using intents as a loyalty index, recommending intents to others, and brand switching intents. And then the study laid the main purpose in trying to provide implications for enhancing customer securities and royalties on the mobile instant messaging service through research's results. The research hypotheses are as follows; H1: Perceived values will affect influences to royalties. H2: Use-Diffusion will affect influences to loyalty. H3: Perceived value will affect influences to loyalty. H4: The use-diffusion will play intermediating roles between perceived values and loyalty. Total 276 cases among collected 284 ones were used for the statistical analysis by SPSS ver. 15 package. Reliability, Factor analysis, regression were done. As the result of research, 'monetary value' and 'emotional value' affected to 'usage' among perceived value factors, and 'emotional value' was appeared as affecting the largest influence. Besides, the usage affected to constant-using intents and recommending intents to others, and using varieties were displayed as affecting to recommending intents to others. On the other hand, 'Using' and 'Using diversity' were appeared as not affecting to 'brand switching intentions'. Meanwhile, as the result of recognizing about effects of perceived values on the loyalty, it was appeared such like 'continued using intents' affected to'functional value', 'monetary value', and 'social value' first, and also 'monetary value', 'emotional value', and 'social value' affected to 'recommending intents to others'. On the other hand, it was shown such like only 'social value' affected influences to 'brand switching intents', and thus contrary results with the factor 'constant-using intents' were displayed. So, it seems that there are many applications to service provides who are worrying about marketing strategies for making consumer retains (constant-using) and new consumer's inductions (brand-switching intents). Finally, as a result of looking into intermediating roles of the use-diffusion factor in relations between conceived values and royalties at hypothesis 4, 'using' and 'using diversity' were displayed as affecting significant influences all together. Regarding to research result's implications, for expanding and promoting continued uses of the mobile instant messaging service by service providers: First, encouraging recognitions on the perceived value connected to users' service usage are necessary. Second, setting up user's use-diffusion strategies are required so as to enhance the loyalty after understanding a fact that use-diffusion patterns affecting to the service's loyalty are different. Finally, methods of raising customer loyalties and making constant relationships have to be grouped by analyzing on what are the customer value's factors that can satisfy users in competitive alterations.

• Journal of Digital Convergence
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• v.10 no.5
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• pp.339-349
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• 2012

Smartphones which represent to the Mobile convergence, is the rapid spread, more than half of Korean are using. Accordingly, mobile apps that run on smartphone market is growing at a rapid pace. However, most studies on smartphone and mobile apps are focusing on the technology acceptance and improvement of function. So, this study is to suggest promotion strategy to each mobile apps, analyzed through three phases. First phase is the frequency analysis that deduct most frequently used mobile apps. Second phase is association rules that found to associate between mobile apps. Finally, to analyze deduction techniques for acquired 5 mobile apps to target variable in pre-2 phase use total 35 variables of 20 mobile apps categories, demographic variables, amount of PC, movie, music, book, game usage and fees per month.