• The Journal of the Acoustical Society of Korea
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• v.21 no.2E
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• pp.91-97
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• 2002

One of the most important things in mobile phone service is Hand-Off (H/O). Meantime soft H/O and softer H/O have been used between the same generations (2G↔2G) and there is little problem. With user's needs and the development of communication technology, the system with different generation coexists and pilot beacon and time-periodic beacon are used for H/O between generations (2.5G↔2G) to start service, but it is not economic and efficient. To improve such problems, ENHHO developed in April 2001 has recently used. Unfortunately, this method also has the defect of momentary cutoff of communication information during the procedure of H/O in case of more than 5 pilot signals. Accordingly, we suggest algorithm to improve the problem of ENHHO and examines its propriety by analyzing the results of field survey using the algorithm.

• Journal of Information Technology Services
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• v.12 no.4
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• pp.205-218
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• 2013

Recently, due to the proliferation of smartphones, users of mobile banking services which are based in wireless Internet without constraint of the time and places are significantly increased. In the study, considering the characteristics of mobile banking services based on the smartphone and the user behavior. we analyse the factors which have an effect on the behavioral intention to use mobile banking services based on the smartphone. For this purpose, we use the model which is based on Technology Acceptance Model (TAM) and add two constructs:the perceived enjoyment and the perceived risk. A survey data for 194 students at the K cyber university is used for statistical analysis. As a result, the perceived ease of use affects the perceived usefulness and the perceived enjoyment, and the perceived ease of use. And the perceived usefulness and perceived enjoyment affect continuous intention to use. On the other hand, the hypothesis which the perceived risk would affect adversely the continuous intention to use is rejected. Through this study, we expect to provide the useful implications for the smartphone banking services and contribute to the development of strategy for them.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.7 no.4
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• pp.834-848
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• 2013

To effectively use these functions many kinds of human-phone interface are used such as touch, voice, and gesture. However, the most important touch interface cannot be used in case of hand disabled person or busy both hands. Although eye tracking is a superb human-computer interface method, it has not been applied to smartphones because of the small screen size, the frequently changing geometric position between the user's face and phone screen, and the low resolution of the frontal cameras. In this paper, a new eye tracking method is proposed to act as a smartphone user interface. To maximize eye image resolution, a zoom lens and three infrared LEDs are adopted. Our proposed method has following novelties. Firstly, appropriate camera specification and image resolution are analyzed in order to smartphone based gaze tracking method. Secondly, facial movement is allowable in case of one eye region is included in image. Thirdly, the proposed method can be operated in case of both landscape and portrait screen modes. Fourthly, only two LED reflective positions are used in order to calculate gaze position on the basis of 2D geometric relation between reflective rectangle and screen. Fifthly, a prototype mock-up design module is made in order to confirm feasibility for applying to actual smart-phone. Experimental results showed that the gaze estimation error was about 31 pixels at a screen resolution of $480{\times}800$ and the average hit ratio of a $5{\times}4$ icon grid was 94.6%.

• Journal of the Korean Society for Precision Engineering
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• v.25 no.9
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• pp.86-94
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• 2008

A total stroke of an opening or closing motion of a hinge mechanism in a folder-type mobile phone is composed of two portions. In the first portion, human fingers act a force to open or close the folder. In this portion, the rotating folder compresses the coil spring installed in the mechanism. In the last portion, this compressed coil spring generates a torque to rotate the folder. The main merit of this study is that we have designed a hinge mechanism to be operated by a uniform torque in the first portion of the total stroke. The uniform torque means that it is constant along the folder's swing angle. This mechanism will give softer feeling to human fingers. A pair of contours in the mechanism plays an important role. It transforms rotation into translation in the first portion; on the other hand, it transforms translation into rotation in the last portion. In this study, we have developed an algorithm to obtain the pair of contour curves. We divided the total contour curves into finite sub-intervals. Assuming that the curves in every sub-interval are parabolas, we have obtained the coefficients of them by solving systems of nonlinear equations recursively.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.9 no.3
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• pp.8-18
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• 2010

A total stroke of an opening or closing motion of a hinge mechanism for a folder-type mobile phone is composed of two portions. In the first portion, human fingers act a torque to open or close the folder. In this portion, the rotating folder compresses the coil spring installed in the hinge mechanism. In the last portion, this compressed coil spring generates a torque to rotate the folder. In this study, we have developed an algorithm to design a hinge mechanism to be operated by an arbitrary continuous torque in the first portion of the total stroke. Consequently, we can design hinge mechanisms that satisfy various demands of consumers. A pair of contours installed in the mechanism plays an important role. It transforms the folder's rotational motion into translation to compress the coil spring in the first portion; on the other hand, it transforms translational motion into the folder's rotation in the last portion. Using this algorithm we have designed the pair of the contour curves operated by an arbitrary continuous torque.

• Journal of the Korea Society of Computer and Information
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• v.16 no.2
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• pp.217-224
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• 2011

Existing wire based physical security system solutions show limitations in time and space. In order to solve these deficiencies, a remote physical security system has been implemented using smart phone based on mobile cloud computing technique. The security functions of mobile cloud computing technique include mobile device user authentication, confidentiality of communication, integrity of information, availability of system, and target system access control, authority management and secure hand off etc. Proposed system has been constructed as remote building management system using smart phone, and also has been efficient to reduce energy cost (5~30%), result of system average access and response time 7.082 second. This systems are evaluated to have high efficiency compared to performance.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.7 no.2
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• pp.202-215
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• 2013

The generalization trend of smartphones has brought many smartphone games into daily lives. These games are mainly dependent on the interactions on the display of the phone using finger touches. On the other hand, functions for detecting the positions and actions of the phones such as gyro-sensors have been rapidly developed over the former orientation sensors and acceleration sensors. Though it has become technologically possible to detect the users' motion via the smartphone devices and to use the phone device directly as the game device, it is hard to find the actualized cases. This paper proposes a new paradigm that includes basic frameworks and algorithms for the games combining the motion tracking and mutual communications on the smartphones and presents the details of its implementation and results.

• Proceedings of the KSRS Conference
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• v.2
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• pp.713-716
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• 2006

The technique of the information communication are advanced recently and a performance enhance of a hand carried computing device was developed rapidly. Mobile Communication Carrier developed currently the phone navigation and are carrying out the service. But such service localizes at the vehicle movement. In This paper, we explain a system structure for the pedestrian navigation of the Wireless Internet Platform for Interoperability(WIPI) mobile phone which contains the MS-Based Global Positioning System(GPS) internally. And we verified the result to be developed by this method that proposes.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2005.06a
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• pp.429-434
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• 2005

In this paper, we investigated EM wave absorption property of EM wave absorbers prepared with sendust. The EM wave absorbers have good EM wave absorption properties in 1 GHz ${\sim}$ 3 GHz. On the other hand, the absorption band of the EM wave absorber coated with $Al(OH)_3$ larger than non-coated one. Pulverization effect of sendust on EM wave absorption properties was also investigated.

• Journal of Institute of Control, Robotics and Systems
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• v.13 no.12
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• pp.1160-1166
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• 2007

This paper presents the design and implementation of an embedded image stabilization control system for a mobile phone with a built-in camera. Image stabilization is a family of techniques for reducing image blur resulting from minute camera shake due to hand-held shooting, thereby allowing the use of shutter speeds slower than values normally required to obtain sharp images. A mechanical image stabilizer mechanism developed for a camera mobile phone is introduced and a digital control system as a part of the image stabilization system is designed and implemented on an 8-bit microcontroller with integer arithmetic in C. This paper focuses primarily on issues that need to be taken into consideration for fixed-point implementation of the digital controller. Several experimental results are presented to demonstrate the performance of the implemented image stabilization control system.