• Journal of Information Technology Services
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• v.11 no.4
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• pp.181-194
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• 2012

The one of the most meaningful change in the recent ubiquitous environment is the omnipresence of public digital display device for providing ubiquitous information. It is the important issue to provide publicity as well as adaptive information to each user in the field of the public digital display device. This research proposes the idea ensuring fast response speed by the selection of user preference function. The preference function is selected by statistics using Zipf distribution in the system comprising mobile device and digital display device based on NFC (Near Field Communication). The idea is proved by CPM-GOMS model and the improvement of user response can be achieved.

• Journal of the HCI Society of Korea
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• v.11 no.1
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• pp.29-38
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• 2016

Mobile tour guide applications help tourists to search for and visit their surrounding POIs(Points of Interest) of their locations and to obtain their guide information. With the development of wearable devices like smart watches and wearable glasses, people using multiple mobile devices are increasing; a tourist may use a hand-held device, a wearable device or both to obtain tour information. However, most mobile tour guides using mobile devices provide the tour information with little consideration of their hand-held and wearable characteristics. In particular, a tourist with multiple mobile devices who search for the tour information from multiple mobile devices must input their intention separately to each device. To alleviate these problems, we propose a mobile tour guide system with the following features: one is to reduce redundant user input by sharing the touring context between hand-held and wearable devices; the other is to present tour information according to capabilities and usage pattern of the devices. The proposed system guides tourists by complementing disadvantage of the devices and also minimizes user interaction between applications and tourists.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.8 no.2
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• pp.709-722
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• 2014

In the $21^{st}$ century, IT reform has led to the development of cyber-infrastructure owing to the outstanding enhancement of computer and network performance. The ripple effect has continued to increase. Accordingly, this study suggests a new computational research environment using mobile devices. In order to simplify the access of supercomputer, Science AppStore, task management and virtualization technologies are developed on mobile devices. User can be able to research by utilizing computational science SW such as compressible flow solver and nano device simulation tool that in installed on supercomputer in mobile environments. Also, this research environment makes it possible to monitor the simulation result and covers 14 university, 33 subjects, and 1,202 individuals.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.22 no.11
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• pp.1511-1517
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• 2018

Mobile Device-to-Device (D2D) caching networks can transmit multimedia data to users directly without passing through any network infrastructure by storing popular multimedia contents in advance that are popular among many mobile users at caching server devices (CSDs) in distributed manners. Thus, mobile D2D caching networks can significantly reduce backhaul traffic in wired networks and service latency time of mobile users. In this paper, we propose an efficient transmission scheme that can enhance the transmission efficiency of mobile D2D caching networks by using multiple CSDs that are caching the contents that are popular among mobile users. By sorting the multiple CSDs that are caching a content that mobile users want to receive according to their channel gains, the proposed scheme can reduce the complexity of algorithm significantly, compared to an optimal scheme based on Brute-force searching, and can also obtain much higher network transmission efficiency than the existing Blanket and Opportunistic transmission schemes.

• Journal of the Korea Society of Computer and Information
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• v.22 no.6
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• pp.95-100
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• 2017

Recently, as stress has become a major threat to people's health, there is a growing interest in wearable stress management services for stress relief. In this paper, we developed a wearable device(Care-on) capable of extracting changeable human voice information at each site and a Healthcare App(S-Manager) that enables stress management in real time using the wearable device. It collects and analyzes variable real-time voice information for each part of the person's body. And It also provides the ability to monitor stress conditions in a mobile environment and provide feedback on the analysis results in step by step in the mobile environment. We tested the developed wearable devices and app in a mobile environment and analyzed the results to confirm their usefulness.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2011.10a
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• pp.765-768
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• 2011

At present, the smart mobile device has been big recognition in general due to fusion, mobility and convenience. On the one hand Industy also needs smart mobile device because more and complex data processing. Hereupon this thesis will study reflected industry needs smart mobile pad's design structure, and applicable area to use this device.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.12
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• pp.5614-5633
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• 2018

Mobile Edge Computing (MEC) and Wireless Power Transfer (WPT) are both recognized as promising techniques, one is for solving the resource insufficient of mobile devices and the other is for powering the mobile device. Naturally, by integrating the two techniques, task will be capable of being executed by the harvested energy which makes it possible that less intrinsic energy consumption for task execution. However, this innovative integration is facing several challenges inevitably. In this paper, we aim at prolonging the battery life of mobile device for which we need to maximize the harvested energy and minimize the consumed energy simultaneously, which is formulated as residual energy maximization (REM) problem where the offloading ratio, energy harvesting time, CPU frequency and transmission power of mobile device are all considered as key factors. To this end, we jointly optimize the offloading ratio, energy harvesting time, CPU frequency and transmission power of mobile device to solve the REM problem. Furthermore, we propose an efficient convex optimization and sequential unconstrained minimization technique based combining method to solve the formulated multi-constrained nonlinear optimization problem. The result shows that our joint optimization outperforms the single optimization on REM problem. Besides, the proposed algorithm is more efficiency.

• International Journal of Advanced Culture Technology
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• v.10 no.4
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• pp.547-554
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• 2022

Due to the expansion of non-face-to-face services, the demand for user identification for mobile devices is increasing. Recently, mobile resident registration cards, mobile driver's licenses, etc. are installed in mobile phones and used for user identification and authentication services. In order to identify a user online, unique identification information of the online user is required. In particular, in order to provide information only to online users, it is necessary to accurately deliver information to a mobile device owned by the user. To make this service possible, it was realized with the advent of mobile electronic notice service. However, the identification of online service users and information on mobile devices owned or subscribed by the relevant users require safe management as personal information, and it is also necessary to increase the convenience of online service users. In this paper, we propose an operating standard for providing a mobile electronic notice service that sends electronic notice using a mobile device owned by the user. The mobile electronic notice service is a service that provides notices expressed in electronic information to the recipient's cell phone, mobile app, e-mail, etc. Therefore, as the use of mobile electronic notification service increases and the provision and use of connecting information to identify users increases, it is necessary to expand the mobile electronic notification service while safely protecting users' personal information.

• Proceedings of the Korea Information Processing Society Conference
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• 2006.11a
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• pp.455-458
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• 2006

John Carmack who invented the 3D games let us know about the great 3D world and because of the MIDP 2.0(Mobile Information Device Profilers entering, it is not a fame to achieve playing 3D games with a mobile device. The data offered by iResearch market consultation show that the figure of mobile game players all around the world will take a steady increase from 290 million in 2005 to 1030 million in 2008, and the market income will mount up from $10,200 million to $52.000 million.3D games will be a current, the most famous kind of mobile games. In this paper I design 3D application based on J2ME (Java 2 Micro Edition) and implement a freely removable 3D object which happened in a 3D scene by receiving the keyboard response of mobile device with WTK (Wireless Too.Kit) simulator.

• 한국정보통신설비학회:학술대회논문집
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• 2008.08a
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• pp.17-20
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• 2008

A clustering scheme for ad hoc networks is aimed at managing a number of mobile devices by utilizing hierarchical structure of the networks. In order to construct and maintain an effective hierarchical structure in ad hoc networks where mobile devices may move at high mobility, the following requirements must be satisfied. The role of each mobile device for the hierarchical structure is adaptive to dynamic change of the topology of the ad hoc networks. The role of each mobile device should thus change autonomously based on the local information. The overhead for management of the hierarchical structure is small. The number of mobile devices in each cluster should thus be almost equivalent. This paper proposes an adaptive multihop clustering scheme for highly mobile ad hoc networks. The results obtained by extensive simulation experiments show that the proposed scheme does not depend on mobility and node degree of mobile devices in the ad hoc network, which satisfy the above requirements.