• Science of Emotion and Sensibility
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• v.11 no.4
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• pp.575-588
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• 2008

This study is to inquire respective patterns of mental models caused by wrongful usages which can be experienced when a user who is used to a keypad-based mobile phone starts using a touch screen mobile phone and to find out the features of the user's logical process of correcting such wrongful usages to a new mental model. In addition, design improvement to be considered for easy generation of the mental model regarding touch screen mobile phones was reviewed in this study. We set up test subjects for the most frequently used seven high priority functions among touch screen phone functions and carried out the subject assessment together with interview surveys after the video observation experiment. Our test results show that test subjects who were used to keypad-based mobile phones tend to use operation knowledge related to the computer operational system(Window) or the web browse, navigation including Tap or Double Tap in order to correct the mental model when a wrongful usage is made. In addition, the result of comparison and analysis of the subject assessment and the video observation experiment data shows that wrongful usages of touch screen mobile phones mostly occurred in the field of 'information feedback' and 'navigation' among mobile phone components.

• Journal of the Korea Society of Computer and Information
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• v.14 no.7
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• pp.73-80
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• 2009

Internet accidents have skyrocketed every year. It always has been threatened by the methods such as hacking and Spyware. The majority of security accident is formed of the loss of authentication information, and the internal user who is not authorized. The importance of security is also emphasized when someone tries to do something accessing to the main information system. Accordingly, Biometrics has been used in many ways. OTP, however, must have a few devices accessing to several systems, and Biometrics involve some risk of mis-recognition rate and mis-denial rate. It also has the risk possible to access to the main information system when losing OTP. This research reduced risks about the loss as separating RFID leader for mobile, Tag and the accessor's cellular phone, and is about pseudo random validation key generated from the administration system through contact with RFID leader for mobile and Tag. As sending the key to user's cell phone which is already registered, security is strengthened more than existing connection methods through the ID and password. RFID for mobile not generalized to the present has been studied as a tool accessing to the main information system.

• The Journal of the Korea Contents Association
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• v.6 no.9
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• pp.98-107
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• 2006

By improving performance of mobile machine(3D engine, 3D accelerator chip set, etc) and developing wireless network technology, a demand for actual contents of users is being increased rapidly. But, there are some difficulties yet for the speedy development of actual contents because of the limitation of development resources that is dependent on each mobile device's different performance. In general, much of the animated character-creation work for mobile environment is still done manually by experienced animator with the method of key frame processing. However, it needs a lot of time and more costs for creating motion. Additionally, it is possible to cause a distortion of motion. In this paper, I solved the difficulties by using a optical motion capture system, it was able to acquire accurate motion data more easily and quickly, and then it was possible to make 3D dance contents efficiently. Also, I showed techniques of key reduction and controlling frame number for using huge amounts of motion capture data in mobile environment which requires less resources. In making 3D dance contents, using an optical motion capture system was verified that it was more efficient to make and use actual-reality contents by creating actual character motion and by decreasing processing time than existing method.

• Journal of Korea Multimedia Society
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• v.10 no.3
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• pp.373-380
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• 2007

In this paper we propose a new efficient authentication protocol that reduces overheads of computation for digital signature generation/verification on mobile devices in the Personal Area Network (PAN). In particular, we focus on eliminating the traditional public key operations on mobile devices without any assistance of a signature server. Moreover, the proposed protocol provides a simplified procedure for certificate status management to alleviate communication and computational costs on mobile devices in the PAN.

• Proceedings of the Korea Information Processing Society Conference
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• 2009.11a
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• pp.635-636
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• 2009

공개키 암호 시스템을 이용하는 공인인증서는 IT 기술의 발달과 함께 e-Banking, e-Commerce, e-Finance 등 다양한 분야에서 사용자 인증을 제공하는 수단으로 사용되고 있다. 그러나 최근에 다양한 해킹툴과 사용자 PC의 취약점을 이용하여 PC에 저장된 공인인증서가 유출되는 사고가 발생하면서 전자금융에 대한 안전성을 위협받고 있다. 따라서 본 논문에서는 기존에 공인인증서를 하드디스크에 저장하여 발생하였던 문제점을 해결하고자 모바일 디바이스를 이용하여 전자서명을 수행하는 MobiSign의 공인인증서 이동방식 및 전자서명 방식을 분석한다. 또한 모바일 환경에서 악성코드에 의해서 발생할 수 있는 MobiSign 서비스의 보안 위협을 분석한다.

• Journal of Digital Convergence
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• v.10 no.2
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• pp.161-169
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• 2012

It requires a lot of costs and manpower to manage the election system. The electronic voting scheme is needed to make the election system to be economic and fair. Especially, wide spread use of smart phones and wireless networks makes the mobile voting is of major concern. In mobile voting scheme, a smart phone user can vote regardless of the places. In this paper, the mobile voting scheme is proposed where candidates can guarantee fairness of the election system. We analyze mobile voting requirements and create the mobile ID which has legal binding forces and PKI based digital signature keys. In the proposed scheme, a voter's ballot is signed by all candidates using undeniable multi-signature scheme. During the counting stage, the multi-signature on the ballot is not verified without help of all candidates.

• Journal of Convergence Society for SMB
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• v.5 no.3
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• pp.21-26
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• 2015

As mobile contents grow up, In App Billing is brisk at applications including mobile contents. But some of users don't pay and use charged content for free to use cheating payment module or hacking through applications. Call this bypass payment. Applications, helping bypass, are Freedom, IAP Cracker, and DNS server suggested by the hacker named Borodin. In case of mobile game, Despite sell a lot of charged content but income is different revenue in sales log with real profits. Because of users using bypass payment application. Management plan to bypass payment are checking OrderID, encrypting public key and verifying receipt.

• Journal of Advanced Marine Engineering and Technology
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• v.39 no.6
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• pp.656-661
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• 2015

The goal of this paper is to analyze the performance of a word autocomplete system for mobile devices such as smartphones, tablets, and PCs. The proposed system automatically completes a partially typed string into a full word, reducing the time and effort required by a user to enter text on these devices. We collect a large amount of data from Twitter and develop both unigram and bigram dictionaries based on the frequency of words. Using these dictionaries, we analyze the performance of the word autocomplete system and devise a keystroke profit rate and recovery rate as new evaluation metrics that better describe the characteristics of the word autocomplete problem compared to previous measures such as the mean reciprocal rank or recall.

• Proceedings of the Korea Multimedia Society Conference
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• 2003.11a
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• pp.158-161
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• 2003

1985년 N. Koblitz와 V. Miller가 각각 독립적으로 제안한 타원곡선 암호시스템(ECC : Elliptic Curve Cryptosystems)은 유한체 위에서 정의된 타원곡선 군에서의 이산대수 어려움에 기초한다. 타원곡선 암호시스템은 다른 공개키 시스템에 비해 보다 짧은 길이의 키만으로도 동일한 수준의 안전도를 유지할 수 있다는 장점으로 인하여, 스마트카드나 모바일 시스템 등에서와 같이 메모리와 처리능력이 제한된 하드웨어에도 이식 가능한 장점이 있다. 본 논문에서는 타원곡선 암호시스템에 필요한 유한체 연산을 이진체(Binary Finite Field)인 GF(2$^{193}$ )과 OEF(Oprimal Extension Field) 상에서 VHDL 언어를 사용하여 구현을 하였고 각 연산의 성능을 비교하였다.

• Proceedings of the Korean Society of Computer Information Conference
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• 2014.07a
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• pp.45-48
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• 2014

디지털 콘텐츠의 급속한 보급과 더불어 휴대용 단말기를 이용한 eBook 관련 콘텐츠의 개발이 점증하고 있는 추세에 유통 다변화를 통한 보급 확대를 위해 스마트 TV를 통한 VOD 방송콘텐츠와 연동하여 전자책을 사용자에게 즉시로 제공할 수 있는 시스템이 요구되고 있다. 본 연구에서는 스마트 TV 방송콘텐츠를 기반으로 한 eBook 콘텐츠의 VOD 서비스를 하이브리드형으로 휴대 스마트 기기에 제공하기 위한 효과적인 시스템의 구성과 DRM 전략을 위한 프레임워크를 제시하고 프로토타입 시스템을 제안한다.