• Journal of KIISE
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• v.44 no.3
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• pp.232-238
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• 2017

Application response time is critical to end-user response time in Android smartphones. Due to the plentiful resources of recent smartphones, storage I/O response time becomes a major key factor in application response time. However, existing storage I/O trace tools for Android and Linux give limited information only for a specific I/O layer which makes it difficult to combine I/O information from different I/O layers, because not helpful for application developer and researchers. In this paper, we propose a novel storage I/O trace tool for Android, called AIOPro (Android I/O profiler). It traces storage I/O from application - Android platform - system call - virtual file system - native file system - page cache - block layer - SCSI layer and device driver. It then combines the storage I/O information from I/O layers by linking them with file information and physical address. Our evaluations of real smartphone usage scenarios and benchmarks show that AIOPro can track storage I/O information from all I/O layers without any data loss under 0.1% system overheads.

• KIPS Transactions on Software and Data Engineering
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• v.2 no.9
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• pp.615-620
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• 2013

With the development of smartphones, the number of applications for smartphone increases sharply. As a result, users need to try several times to find their favorite apps. In order to solve this problem, we propose a recommendation system to provide an appropriate app list based on the user's log information including time stamp, location, application list, and so on. The proposed approach learns three recommendation models including Naive-Bayesian model, SVM model, and Most-Frequent Usage model using temporal and spatial attributes. In order to figure out the best model, we compared the performance of these models with variant features, and suggest an hybrid method to improve the performance of single models.

• KIPS Transactions on Software and Data Engineering
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• v.4 no.12
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• pp.561-570
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• 2015

With the advance of IT technology, contents from digital multimedia devices and softwares are widely used and distributed. However, novice uses them for illegal purpose and hence there are needs for protecting contents and blocking illegal usage through multimedia forensics. In this paper, we present a forensic technique for identifying digital imaging source using sensor pattern noise. First, the way to acquire the sensor pattern noise which comes from the imperfection of photon detector against light is presented. Then, the way to identify the similarity of digital imaging sources is explained after estimating the sensor pattern noises from the reference images and the unknown image. For the performance analysis of the proposed technique, 10 devices including DSLR camera, compact camera, smartphone and camcorder are tested and quantitatively analyzed. Based on the results, the proposed technique can achieve the 99.6% identification accuracy.

• Journal of the Korean Society for Library and Information Science
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• v.57 no.1
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• pp.5-21
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• 2023

The purpose of this study is to analyze how library visitors use spaces in the library and to make suggestions for improving library use environments. Library use patterns were analyzed by tracking the users' smartphone WiFi. A library located in Seoul, Korea was selected and detectors were installed in the library. The suggestions from the results analyzing data collected between September, 2016 and December, 2016 were as followed. 27.17% of library visitors used a space in the library. Among them, 28.69% used the lobby to return their checked-out materials. Therefore, the library is recommended to install a device in the area in which users are easy to return their items. Additionally, since the spatial relationship between cultural program room and book shelves was low, those programs might be improved by providing library materials related with them.

• Journal of Digital Convergence
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• v.17 no.12
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• pp.467-472
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• 2019

Growing smartphone usage in South Korea has also accelerated the pace of development of mobile games, but competition is intensifying as the market grows. As one of the factors for the success of the game in this mobile game market, UI has been presented, suggesting that the design of such mobile game UI should be approached in terms of designing the user's experience, along with its function, aesthetic expression, function-oriented design and information delivery before. In this paper, we propose an effective lobby layout of mobile RPG using experience among UX factors. Through the layout classification of Ernest Adams and Andrew Rollings, we selected 9 mobile RPGs in the 20th place of google play cumulative sales rankings and analyzed the layout of the lobby. As a result, the lobby layout of the game, which led the first market success of the mobile RPG genre, The result was that it became the standard of the boxed game. It can be interpreted that the lobby layout, which is similar to the game used previously by the user, is effective because low entry barriers and learning are unnecessary due to the experience of using the existing RPG. Future studies may produce a common layout of a broad genre if studies are conducted to measure the optimum UX for other genres than RPG.

• Annals of Occupational and Environmental Medicine
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• v.35
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• pp.50.1-50.11
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• 2023

Background: The rise in telecommuting or non-face-to-face work owing to the coronavirus disease 2019 pandemic has fueled conversations regarding the "right to disconnect." Although evidence suggests that receiving work-related communications through telecommunication devices outside of work hours may lead to various symptoms and illnesses, limited research has been undertaken on these symptoms. This study therefore aims to investigate the correlation between receiving work communications through telecommunication devices after work hours and the occurrence of work-related headaches and eyestrain in full-time, non-shift white-collar workers. Methods: This study used data from the 6th Korean Working Conditions Survey. The frequency of using telecommunication devices for work purposes outside of working hours was divided into five categories: "Every day," "Several times a week," "Several times a month," "Rarely," and "Never." Work-related headaches and eyestrain were categorized based on a "yes" or "no" response to the survey questions. Descriptive statistics, χ² tests, and multiple logistic regression analyses were performed using SPSS 27.0. Results: After adjusting for sex, age, income level, education, occupation, workplace size, work hours, and sleep disorders, the odds ratio (OR) of work-related headaches and eyestrain based on frequency of telecommunication device usage were as follows: "rarely" (OR: 1.292; 95% confidence interval [CI]: 1.111-1.503), "several times a month" (OR: 1.551; 95% CI: 1.249-1.926), "several times a week" (OR: 1.474; 95% CI: 1.217-1.784), and "every day" (OR: 1.548; 95% CI: 1.321-1.813). Conclusions: Employees who use telecommunication devices for work after regular hours are more susceptible to experiencing work-related headaches and eyestrain compared to those who do not. However, there is a dearth of research examining the physical and mental health impacts of using telecommunication devices for after-hours work. Furthermore, the existing preventative measures in Korea are insufficient. Consequently, it is imperative to develop effective measures and conduct additional research to address this issue.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.4
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• pp.2349-2354
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• 2014

While the number of smart phone subscribers excessing 30 million people, Korea is leaping into the 'smart powerhouse' from IT powerhouse. The popularizat+ion of smart devices so called 'PC in the hand', brought surely change to people's life style, and also it had led to a revolutionary change to and also to business and government. In several corporations of each countries, a variety of smart devices smart devices such as smart phone, tablet PC and E-books have been developing. Nowadays, the usage of the smart phone is not only the simple function calling. It has become a culture of the terminal type in the hand anywhere at any time, which makes can communicate with the others in anywhere and anytime. However, some of the subscribers who visit the website for PC version with the mobile devices screen, can feel kind of discomfort while surfing the net on a smartphone devices because the install of the existing video and flash files and the screen size for computer is not available for mobile devices. Therefore, in this paper, we studied on effective mobile contents generation program using QR code that is two dimensions bar code under the smart device environment. Also, unlike previous QR code generator that decorate standardized design, we realize an original QR code generation system from user perspective.

• Journal of Digital Convergence
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• v.13 no.10
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• pp.501-508
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• 2015

This study intends to look into the perception gap among Korean and Chinese consumers regarding the product attitudes toward smart phones and repurchase intention as well as the user experience. First, this study showed that there are gaps among Korean and Chinese consumers, regarding smart phones, toward their experiences of usage satisfaction, usefulness, design satisfaction, and evaluation from other people and that Chinese consumers have higher awareness of every experience element concerning UI than Korean consumers. Second, concerning the difference in the product attitudes toward smart phones, it turns out that Chinese consumers also have higher awareness of it than Korean consumers. Third, regarding the difference in repurchase intention for smart phones among Korean and Chinese consumers, this study shows that Chinese consumers are likely to have more intention than Korean consumers. because their average value is higher than Korean consumers' even though the difference are not statistically significant. This study is expected to have academic meaning(significance) for providing basic materials of comparative study between two countries regarding the user experience about smart phone as well as some useful implications for the competitive power improvement of Korean smart phone related companies in China.

• Journal of the Korea Society of Computer and Information
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• v.24 no.12
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• pp.201-207
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• 2019

In this paper, we propose an effective method to block illegal gambling advertisement on social media. With the increase of smartphone and internet usage, users can easily access various information while sharing information such as text and video with a large number of others. In addition, illegal sports gambling advertisements are also continue to be transmitted on SNS. To avoid most surveillance networks, users are easily exposed to illegal sports gambling advertisement images by including phrases in the images that indicate illegal sports gambling advertisements. In order to cope with these problems, we proposed a method to actively block illegal sports gambling advertisements in a way different from the conventional passive methods. In this paper, we select words frequently used for illegal sports gambling, classifies them into three groups according to their importance, calculate WF for each word using weighted formula by degree of relevance and frequency, and then sum the WF of the words in the image. Blocking, warning, and passing were determined by cv, the total of WF. Experimenting with the proposed method, 193 out of 200 experimental images were correctly judged with 96.5% accuracy, and even though 7 images were illegal sports gambling advertisements. Further research is needed to block 3.5% of illegal sports betting ads that cannot be blocked in the future.

• KIISE Transactions on Computing Practices
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• v.22 no.8
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• pp.375-380
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• 2016

The proliferation of online social networking services (OSNSs) and smartphones has enabled people to easily make friends with a large number of users in the online communities, and interact with each other. This leads to an increase in the usage rate of OSNSs. However, individuals who have immersed into their digital lives, prioritizing the virtual world against the real one, become more and more isolated in the physical world. Thus, their socialization processes that are undertaken only through lots of face-to-face interactions and trial-and-errors are apt to be neglected via 'Add Friend' kind of functions in OSNSs. In this paper, we present a friend recommendation system based on the on/off-line contextual information for the OSNS users to have more serendipitous offline interactions. In order to accomplish this, we modeled both offline information (i.e., place visit history) collected from a user's smartphone on a 3D tensor, and online social data (i.e., friend relationships) from Facebook on a matrix. We then recommended like-minded people and encouraged their offline interactions. We evaluated the users' satisfaction based on a real-world dataset collected from 43 users (12 on-campus users and 31 users randomly selected from Facebook friends of on-campus users).