• Journal of KIISE:Software and Applications
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• v.37 no.10
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• pp.736-744
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• 2010

Log data collected from mobile devices contain diverse and meaningful personal information. However, it is not easy to implement a context-aware mobile agent using this personal information due to the inherent limitation in mobile platform such as memory capacity, computation power and its difficulty of analysis of the data. We propose a method of selective inference for modular Bayesian Network for context-aware mobile agent with effectiveness and reliability. Each BN module performs inference only when it can change the result by comparing to the history module which contains evidences and posterior probability, and gets results effectively using a method of influence score of the modules. We adopt memory decay theory and virtual linking method for the evaluation of the reliability and conservation of casual relationship between BN modules, respectively. Finally, we confirm the usefulness of the proposed method by several experiments on mobile phones.

• Journal of the HCI Society of Korea
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• v.6 no.1
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• pp.27-33
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• 2011

The battery lifetime is one of the most important factors in product qualities of mobile devices such as mobile phones, MP3 players, PMP. It is used to be displayed by a 'battery bar' icon with uniformly divided three or four blocks. However, several manufacturers of mobile phones have assigned uneven time ratios to each battery block because they believe that it can make users feel more long in battery lifetime. In this study, two experiments were performed. The first is to verify the effects of the uneven time ratios in each battery block on users' cognitive awareness of battery lifetime. The second is to investigate whether the compatibility between battery displays and actual time ratios affects the users' time perceptions. The results show that as low battery bar is maintained for a long time, users tend to be aware of the battery lifetime shorter. On the contrary, maintaining full battery status longer does not affect the users' time perception. These results can be applied as the guidelines for determining proper time ratios in designing the battery bar indicator of mobile devices.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.11 no.6
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• pp.207-214
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• 2011

In this paper, using Zigbee-based wireless sensor networks and Lego MindStorms NXT robot, a remote monitoring and navigation system for mobile robot has been developed. Mobile robot can estimate its position using encoder values of its motor, but due to the existing friction and shortage of motor power etc., error occurs. To fix this problem and obtain more accurate position of mobile robot, a ultrasound module on wireless sensor networks has been used in this paper. To overcome disadvantages of ultrasound which include straightforwardness and narrow detection coverage, we rotate moving node attached to mobile robot by $360^{\circ}$ to measure each distance from four fixed nodes. Then location of mobile robot is estimated by triangulation using measured distance values. In addition, images are sent via a network using a USB Web camera to smart phone. On smart phones we can see location of robot, and images around places where robot navigates. And remote monitoring and navigation is possible by just clicking points at the map on smart phones.

• Journal of the Korea Society of Computer and Information
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• v.25 no.8
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• pp.173-179
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• 2020

The purpose of this study was to examine the effects of peer attachment and parental abuse on adolescents' dependence on mobile phones and the mediating effect of self-esteem. For this study, I used the panel data of the 7th year of the 1st grade of the elementary school for the Korean Children and Youth Panel Survey provided by the Korea Youth Policy Institute. A total of 1,937 adolescents were selected to analyze causal relationship among variables, and SPSS 26.0 and AMOS 26.0 were used to verify research problem. As a result of the study, First, the better the relationship with peers, the higher the self-esteem and the less the dependence on their mobile phone. On the other hand, the more severe the abuse, the lower the self-esteem and the higher the dependence on mobile phones. Second, Self-esteem was found to have a significant effect on peer attachment and abuse on mobile phone dependence. Based on these results, I would like to provide them as basic data for helping positive development of adolescents.

• Journal of Digital Convergence
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• v.14 no.8
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• pp.383-391
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• 2016

Purpose: This study was conducted to analyze the effect of ego resilience, peer attachment and mobile phone-related characteristics on mobile phones functional uses, focused on the use of SNS & messenger and music and internet in middle school students. Methods: The subjects were 217 middle school students in 2 cities. Results: The factors affecting mobile phones SNS & messenger usages were interpersonal relation, viability of ego-resilience in male, and communication of peer attachment in female. The factors affecting internet usages were curiosity of ego-resilience in both sexes. The factors affecting music usages were viability of ego-resilience in both sexes. Conclusion: Education and management about mobile phone functional use should be made, by intervening reflected subregions effect factors of peer attachment and ego-resilience.

• Journal of the Ergonomics Society of Korea
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• v.25 no.4
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• pp.51-62
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• 2006

The concept of universal design has recently emerged as an important aspect of product design. Universal design is considerably analogous to ergonomic design in a way that it takes the capabilities and limitations of users into consideration during the product development process. However, relatively few studies have been devoted to reflect the practical use of ergonomic principles on universal design. This research attempts to develop a universal design index for mobile phone design to quantify how well a product complies with principles of universal design. The research also emphasizes on ergonomic principles as a basis of evaluation. A generation of the evaluation items was done by cross-checking among the personal, activity and product components. Personal components consist of human characteristics including age, physique, perceptual capacity, life-style, etc. Activity components were derived from those scenarios of mobile phone use while product components were composed of the parts to which a user interacts. Further analysis systematically generated a universal index from relationship matrices among the three components. The index was then used to test its suitability by applying to the evaluation of mobile phones currently on the market. This study demonstrates a development process through which evaluations can be made possible for universal design. The research suggests an improved approach to the appraisal of how well mobile phones are universally designed based on ergonomic principles.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2017.05a
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• pp.800-801
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• 2017

Location-based services (LBS) are used in various applications such as emergency support, navigation, location, traffic routes, information gathering, and entertainment due to the rapid growth of information communication technologies and mobile phones. In general, locations are represented by coordinates and are related to terrain. These are of great interest in mobile-based data transmission. This paper proposes a method to exchange the contact of the other party by detecting the movement of the mobile phone of the individual user based on the location-based service. The proposed method extracts motion using the acceleration sensor of the mobile phone and transmits the location and time information to the server when the motion continues for a predetermined time. Attempts to establish a connection between users who are experiencing motion in mobile phones in the short distance have been made from the server. Once the connection between the users is made, the encrypted contact is received from the server. Experimental results show that the proposed method can exchange data by minimizing the processing in the handset compared with the existing method.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2012.10a
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• pp.51-52
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• 2012

Safety at sea continues to be an important topic for research. The factors that contribute to safety issues are often complex and unclear. Lack of non-technical skills in such areas as communication, teamworking, situational awareness, decision making etc. are well documented as directly affecting safety in high risk work settings such as on board merchant vessels. Competence in non-technical skills can be affected by various habits and circumstances that influence a worker and result in either positive thinking and behaviour or negative thinking and behaviour. Negative thinking can cause stress, anger, frustration; loneliness etc. and this can possibly result in behaviour or actions that undermine the safety of crew and ship. Factors that may contribute to these negative thoughts and behaviours are many and varied and this paper will be looking at one aspect: mobile phone use. In the Republic of Korea, dependency on mobile phones is uniquely high. Maritime students are also susceptible to such dependency and this paper will demonstrate that the symptoms associated with mobile phone addiction and dependency, and in particular the symptoms of withdrawal, are important factors that need to be mitigated in order to improve safety at sea. Although the benefits of mobile phones are many it will be suggested that over-reliance, dependency or addiction can result in negative thinking or behaviour that may directly or indirectly contribute to the factors that cause incidents and accidents at sea. It will be suggested that the most appropriate method of dealing with this problem is twofold: firstly, through training at the educational level and secondly, by encouraging the shipping industry and government to invest more into providing seafarers with better access to the communication methods that they are used to on shore in order to improve work conditions.

• Land and Housing Review
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• v.14 no.2
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• pp.109-124
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• 2023

The purpose of this study was to implement a mobile application to evaluate the residential performance of Hanoks anytime and anyplace free of time and space constraints made possible by mobile devices such as smart phones. To effectively evaluate the performance of Hanoks, the mobile application includes architectural information and help functions to ease the usability by the general public. In addition, it is designed to be intuitively understood through the presentation of field photos through empirical cases in line with the functional characteristics of smart phones. To test the functionality of the mobile application, a field evaluation was conducted at the Set-yi-seo Literature Center in Eunpyeong Hanok Village. The findings of this study provide a basis for using smart phone based applications for evaluating buildings such as Hanoks in the future. It can be used as a model for developing future user-friendly performance evaluation applications for public Hanok research and development.

• Journal of Korea Society of Digital Industry and Information Management
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• v.7 no.3
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• pp.85-95
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• 2011

Smart phones, greatly expanding in the recent mobile market, are equipped with various features compared to existing feature phones and provide the conveniences to in several ways. The camera, one of the features of a smartphone, creates the digital contents, such photos and videos, and plays a role for the media which transmits information, such as video calls and bar code reader. QR-Code recognition is also one of the camera features. It contains a variety of information in two-dimensional bar code type in matrix format, and makes it possible to obtain the information by using smart phones. This paper analyzes the method of QR-Code recognition, password method-the existing user-authentication technique, smart card, biometrics and voice recognition and so on and thenn designs a new user-authentication technique. The proposed user-authentication technique is the technique in which QR-Code, which can be simply granted is read by smart phones and transmitted to a server, for authentication. It has the advantages in view that it will simply the process of authentication and conteract the disadvantages, such as brute force attack, man-inthe-middle attack, and keyboard hacking, which may occur in other authentication techniques.