• Journal of the Ergonomics Society of Korea
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• v.30 no.1
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• pp.259-264
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• 2011

Does preferred hand show better performance than non-preferred hand in smart phone text entry using one hand. Is the performance of subjects who use left-preferred hand in smart phone text entry worse than that of others who use right preferred hand among the right handed. This study tried to address these two questions. Thirty young male undergraduate students typed a text using a smart phone which has a touch-based QWERTY keyboard two times with both hands, right and left hand, respectively. The completion time, errors were measured in the text entry tasks. All of participants were right handed, but half of them preferred right hand if they have to use one hand in smart phone text entry and other half preferred left hand. The percentage that preferred hand has better performance than non-preferred hand in smart phone text entry using one hand is less than 90% for right-preferred hand and less than 70% for left-preferred hand. The performance of left hand preferred students is not worse than that of the right hand preferred in one hand text entry of smart phone.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.12 no.6
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• pp.279-283
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• 2012

In is paper, we design and implement the low power, high speed touch screen controller that calculates and outputs the coordinate of touch point on the touch screen of mobile devices. The system clock is 10HMz, the number of input channels is 21, standby current is $20{\mu}A$, dynamic range of input is 140pF~400pF and the response time is 0.1ms/frame. It contains the power management unit for low power, automatic impedance calibration unit in order to adapt to humidity, temperature and evaluation board, adjacent key and pattern interference suppression unit, serial interface unit of I2C and SPI. The function and performance is verified by using FPGA and $0.18{\mu}m$ CMOS standard process. The implemented touch screen is designed for using in the double layer ITO(Indium Thin Oxide) module with diamond pattern and single layer ITO module for cost-effective which are applied to mobile phone or smart remote controller.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.21 no.1
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• pp.135-141
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• 2011

Recent advances in mobile devices and development of various mobile applications dealing with private information of users made user authentication in mobile devices a very important issue. This paper presents a new user authentication method based on touch screen interfaces. This method uses for authentication the PIN digits as well as the exact locations the user touches to input these digits. Our method is fully compatible with the regular PIN entry method which uses numeric keypads, and it provides better usability than the behavioral biometric schemes because its PIN registration process is much simpler. According to our experiments, our method guarantees EERs of 12.8%, 8.3%, and 9.3% for 4-digit PINs, 6-digit PINs, and 11-digit cell phone numbers, respectively, under the extremely conservative assumption that all users have the same PIN digits and cell phone numbers. Thus we can guarantee much higher performance in identification functionality by applying this result to a more practical situation where every user uses distinct PIN and sell phone number. Finally, our method is far more secure than the regular PIN entry method, which is verified by our experiments where attackers are required to recover a PIN after observing the PIN entry processes of the regular PIN and our method under the same level of security parameters.

• Journal of Industrial Convergence
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• v.20 no.11
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• pp.191-196
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• 2022

In the fintech field, financial transactions with smart phones are actively conducted. User authentication technology is essential for safe financial transactions. PIN authentication through the existing security keypads is convenient to input but has weaknesses in security and others. The biometric authentication technique is secure, but there is a possibility of false positive and false negative authentication. To compensate for this, two-factor authentication is used. In this paper, we propose the 1.5-factor authentication that can increase convenience and security through PIN input with biometric authentication. It provides the stability of fingerprint authentication and convenience of two or three PIN inputs, and this makes safe financial transaction possible. Since biometric authentication is performed at the same time when entering PIN, while security is required by applying fingerprint authentication to the area touched while entering PIN. The User authentication is performed while ensuring convenience to input through additional PIN input in situations where high safety is required, and Safe financial transactions are possible.

• Journal of Korea Society of Digital Industry and Information Management
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• v.6 no.4
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• pp.237-250
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• 2010

The present paper focuses on the comparison of user experience of mobile phone keypad and touchpad. Mobile phone has recently adopted a touchpad keyboard style and it gives users advantages and disadvantages as well. This paper examined usability, usefulness, affect and attitude of those two keyboard styles and disclosed interesting outcomes. First, keypad is better than touchpad in usefulness and usability. Second, touchpad is better than keypad in affect. Finally, touchpad is better than keypad in attitude. Overall, although touchapd is evaluated as worse keyboard in usability and usefulness, test subjects favored touchpad keyboard because it is more emotional and affective. It implies new digital device including mobile phone has to get more affective appeal to the young users and emotion will be a key point in digital consumption.

• Proceedings of the Korea Information Processing Society Conference
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• 2003.11c
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• pp.1767-1770
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• 2003

PDA 는 터치패드 방식의 문자 입력을 한다. 따라서 사용자에게 긴 입력을 요구할 때 불편한 환경을 제공한다. 따라서 이미지의 특정 지점을 마우스로 선택함으로 문자입력을 대신하여 인증을 함으로써 편리한 환경을 제공한다. 보안을 제공하기 위하여 초기 이미지에 따른 이미지의 배열 정보 및 입력된 값을 해시코드화 하여 인증 및 키교환이 안전하게 이루어진다. HASH와 SEED 암호화 알고리즘을 적용하여 효율적이고, 전송 메시지의 무결성을 보장하며 내부 참여자에 의한 정보 유출이 있더라도 안전한 전자지불 프로토콜 시스템을 설계 및 구현하였다.

• Proceedings of the KAIS Fall Conference
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• 2010.05a
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• pp.221-224
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• 2010

본 논문에서는 레이저 포인터를 이용하여 지능형 오피스 환경을 자유롭게 제어 할 수 있는 지능형 정보처리 시스템을 제안한다. 저가의 웹캠을 이용하여 카메라로부터 입력된 레이저 포인터 스팟의 위치를 자동 검출한 후 검출된 위치좌표정보를 컴퓨터상의 제어 명령 이벤트와 매칭 시킨다. 매칭이 이루어 진 후 사용자는 레이저 포인터를 이동시키면서 보조자의 도움 없이 자유롭게 디스플레이 화면을 제어할 수 있다. 사용자는 화면상의 임의의 영역을 특정 명령영역으로 지정할 수 있는 가상 키패드 인터페이스를 통해 특정 프로그램이나 가전 기기를 제어할 수 있다. 실험 결과를 통해 제안한 시스템이 기존의 원격 제어 방법에 비해 가격이나 성능 면에서 뛰어난 결과를 보임을 확인할 수 있다.

• Journal of Korea Multimedia Society
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• v.17 no.10
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• pp.1213-1219
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• 2014

Keypad used in the portable terminal based on the touch screen such as current smart phones is complex on the input method because of placement for use a small screen on a character or number button and is inconvenient. In this paper, we propose a combination method for the Hangul through touch and drag. First, only keypad for consonants is displayed, if a single consonant is selected by touch, then the keypad for vowels will be displayed around the consonant. Dragging in the keypad is combined into a vowel by depending on the drag path. This method can input Hangul by rapid and intuitive process compared to conventional methods. Simulation results show that the proposed method is very efficient in terms of speed and convenience compared to the conventional methods.

• Journal of Korean Institute of Industrial Engineers
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• v.38 no.2
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• pp.80-88
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• 2012

This paper focuses on small touch key size and spacing that affect the usability of the smart phones. The experiments examined thirty-six different touch key designs, combinations of four touch key sizes (width (mm) ${\times}$height (mm); $4{\times}4$, $4{\times}7$, $7{\times}4$, and $7{\times}7$), and nine spacings (horizontal (mm)${\times}$vertical (mm); $0{\times}0$, $0{\times}1$, $0{\times}3$, $1{\times}0$, $1{\times}1$, $1{\times}3$, $3{\times}0$, $3{\times}1$, and $3{\times}3$). Forty participants volunteered in the experiment. The completion time, error rate, identification discomfort, and control discomfort were measured. The results revealed that the touch key sizes of $7{\times}7$ and $7{\times}4$ provide the best performance in terms of the error rate measure, while the touch key size of $7{\times}7$ provides the best results for other measures. In addition, touch key spacings of $1{\times}1$, $1{\times}3$ and $3{\times}1$ are regarded as the best for all the measures. The results of this study suggest a practical approach for the small touch key design for the smart phones.

• Journal of Korean Institute of Industrial Engineers
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• v.37 no.1
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• pp.30-40
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• 2011

In recent years, driver information systems (DIS's) became popular and the use of DIS's increased significantly. A majority of DIS's provides touch-screen interfaces because of intuitiveness of the interaction and the flexibility of interface design. In many cases, touch-screen interfaces are mainly manipulated by fingers. In this case, investigating the effect of touch-key sizes on usability is known to be one of the most important research issues, and lots of studies address the effect of touch-key size for mobile devices or kiosks. However, there is few study on DIS's. The importance of touch-key size study for DIS's should be emphasized because it is closely related to safety issues besides usability issues. In this study, we investigated the effect of touch-key sizes of DIS's while simulated driving (0, 50, and 100km/h) considering driving safety (lateral deviation, velocity deviation, total glance time, mean glance time, total time between glances, mean number of glances) and usability of DIS's (task completion time, error rate, subjective preference, NASA TLX) simultaneously. As a result, both of driving safety and usability of DIS's increased as driving speed decreased and touch-key size increased. However, there were no significant differences when touch-key size is larger than a certain level (in this study : 17.5mm).