• Journal of Korean Institute of Industrial Engineers
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• v.35 no.1
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• pp.109-118
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• 2009

While driving, the manual use of a mobile phone is heavily restricted due to the interference with the primary driving task. An alternative would be the use of speech interface. The current study aims to provide a guideline to implementation of a speech interface to the mobile phone. To do so, an expert evaluation was made and it revealed that a speech interface requires less workload, less performance degradation of the driving task than that of the keypad interface. To make speech interfaces more usable, new improvements are suggested. Subjective workload can be reduced and user satisfaction can be improved without degrading the primary task performance, for instance, by letting the user interrupt the speech of the phone, eliminating the repetitive words, letting the user know clearly what makes an error, providing a way to go back to the previous state, reducing the usage of keypad buttons and reducing the amount of the information on the screen.

• KIPS Transactions on Software and Data Engineering
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• v.2 no.6
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• pp.423-432
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• 2013

Smart phones have been technologically advanced in many ways from basic cellular phones. However, most of all smart phone users in Korea still have been using the traditional Korean character keypads used in the basic cellular phones. It would be required to develop new keypads on smart phones with touch screen. In this paper, we extended the three standard Korean character keypads - Cheonjiin, Naragul, and SKY-Hangul - by adding dragging function on touch screen, then we compared writing speeds of the keypads based on the number of touching buttons and moving distance of the finger while writing a sentence. In addition, we proposed two new Korean keypads - 's-Gana' and 's-Bada', which are more suitable on smart phones. s-Gana assigned 7 representative consonants and 5 representative vowels in order on the 4x3 keypad, and s-Bada assigned consonants and vowels by considering their frequency of use. s-Gana and s-Bada keypads showed 3~19% and 9~24% of performance improvement, respectively, compared with the standard Korean keypads. Finally, we set up 5 requisites of SELF-T in order to evaluate the usability of Korean character keypads in smart phones, then we compared the keypads using the requisites.

• 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 Korea Game Society
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• v.7 no.3
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• pp.67-76
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• 2007

As the performance of game consoles is so highly progressed that services such as internet browsing become available on the consoles, the need for text input schemes on game consoles is rapidly raised. In this paper, we present a text input method of alphabet characters and several symbols using a gamepad, which is a widely used input device for most game consoles. Just like other text input methods using gamepad, our method allows users to enter texts by manipulating the gamepad with a user interface displayed on the screen of the console. A key idea of this paper is to present the user interface that is similar to the $4{\times}3$ keypad on mobile phones. The motivation of this idea is a principle that the experience of using a text input tool can be transferred to another tool that has similar interface. Another motivation is that the keyboard-based interface is too complex to be easily manipulated by simple input from a keypad, which is four orthogonal directions and several fire signals. Since most of keys on keypad of $4{\times}3$ keys are represented by a combination of two orthogonal directions, users feel easier in entering texts using keypad-based interface. We prove this argument in this paper by a user test of ten subjects. After about two experiment sessions, subjects reach 13 WPM in average, which proves that the proposed text input method enables much faster text input than the existing keyboard-based text input methods.

• Journal of the Korea Convergence Society
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• v.8 no.6
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• pp.37-44
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• 2017

Mobile devices provide various services through payment and authentication by inputting important information such as passwords on the screen with the virtual keypads. In order to infer the password inputted by the user, the attacker captures the user's touch location information. The attacker is able to infer the password by using the location information or to obtain password information by peeping with Google Glass or Shoulder Surfing Attack. As existing secure keypads place the same letters in a set order except for few keys, considering handy input, they are vulnerable to attacks from Google Glass and Shoulder Surfing Attack. Secure keypads are able to improve security by rearranging various shapes and locations. In this paper, we propose secure keypads that generates 13 different shapes and sizes of Tetris and arranges keypads to be attached one another. Since the keypad arranges different shapes and sizes like the game, Tetris, for the virtual keypad to be different, it is difficult to infer the inputted password because of changes in size even though the attacker knows the touch location information.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.26 no.5
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• pp.656-661
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• 2022

Password with a combination of 4-digit numbers has been widely adopted for various authentication systems (such as credit card authentication, digital door lock systems and so on). However, this system could not be safe because the 4-digit password can easily be stolen by predicting it from the fingermarks on the keypad or display screen. Furthermore, due to the prolonged COVID-19 pandemic, contactless method has been preferred over contact method in authentication. This paper suggests a new password input method based on eyeblink pattern analysis in video sequence. In the proposed method, when someone stands in front of a camera, the sequence of eyeblink motions is captured (according to counting signal from 0 to 9 or 9 to 0), analyzed and encoded, producing the desired 4-digit decimal numbers. One does not need to touch something like keypad or perform an exaggerated action, which can become a very important clue for intruders to predict the password.

• Journal of the Ergonomics Society of Korea
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• v.35 no.6
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• pp.569-580
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• 2016

Objective: This study aims to identify the most effective keyboard layout in the area of performance for securing usability in a smart watch-using environment and to verify the usability of touch keyboard calibrated by hand. Background: It is necessary to understand the environmental characteristics in using the smart watch and to secure the usability of touch keyboard based on this understanding in order to take account of the users who use the touch screen in the extreme input conditions caused by the small screen of a smart watch. Method: 30 participants in this study were required to input characters using the QWERTY keyboard and 3x4 keypad (Naratgul, Chunjiin), which were familiar with them, in order to grasp the keyboard layout suitable in the smart watch- using environment; the performance (error rate, performance time) of this case was measured. In addition, 30 participants in this study were required to input the characters setting the QWERTY keyboard with calibrated touch area and the one with uncalibrated touch area, based on the characteristics of touch behavior, by finger typing the keyboard, with the performance (error rate and performance time) of this case measured. Results: QWERTY keyboard (93.3sec) is found to be 31.2% faster than Naratgul keyboard, a kind of 3x4 keypad, and 43.6% faster than Chunjiin keyboard, in the area of efficiency, in the results of the usability evaluation regarding the keyboard layout. QWERTY keyboard with calibrated touch area (7.5%) is found to be 23.5% improved compared to the QWERTY keyboard with uncalibrated touch area (9.8%) in the area of accuracy (error rate). The results of the usability evaluation regarding the QWERTY keyboard with touch area calibrated by finger typing the keyboard and QWERTY keyboard with calibrated touch area (80.7sec) is found to be 5.7% improved compared to QWERTY keyboard with uncalibrated touch area (85.6sec) in the area of efficiency (performance time). Conclusion: QWERTY keyboard is found to have an effective layout in the area of efficiency in the smart watch-using environment, and its improved usability is verified in the areas of accuracy and efficiency in the QWERTY keyboard with a touch area calibrated by finger typing the keyboard. Application: The results of this study may be used to set up the basic touch keyboard of the smart watch. The input usability is expected to secure the smart watch-using environment, which is an extreme input condition by applying QWERTY keyboard with touch area calibrated by finger typing the keyboard.

• Archives of design research
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• v.17 no.3
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• pp.441-448
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• 2004

Mobile devices such as mobile phones or PDAs are considered as main interlace tools in ubiquitous computing environment. For searching information in mobile device, it should be possible for user to input some text as well as to control cursor for navigation. So, we should find efficient interlace method for text input in limited dimension of mobile devices. This study intends to suggest a new approach to mobile interaction using camera based virtual keyboard for text input in mobile devices. We developed a camera based virtual keyboard prototype using a PC camera and a small size LCD display. User can move the prototype in the air to control the cursor over keyboard layout in screen and input text by pressing a button. The new interaction method in this study is evaluated as competitive compared to mobile phone keypad in left input efficiency. And the new method can be operated by one hand and make it possible to design smaller device by eliminating keyboard part. The new interaction method can be applied to text input method for mobile devices requiring especially small dimension. And this method can be modified to selection and navigation method for wireless internet contents on small screen devices.

• The Journal of the Korea Contents Association
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• v.11 no.12
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• pp.12-18
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• 2011

Most smartphone use virtual keypads based on touch-pad. The virtual keypads often make typographical errors because of the physical limitations of device such as small screen and limited input methods. To resolve this problem, many similar word-finding methods have been studied. In the paper, we propose an edit distance method (a well-known string similarity measure) that is modified to consider various types of virtual keypads. The proposed method effectively covers typographical errors in various keypads by converting an input string into a physical key sequence and by reflecting characteristics of virtual keypads to edit scores. In the experiments with various keypads, the proposed method showed better performances than a typical edit distance method.

• The KIPS Transactions:PartA
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• v.12A no.7 s.97
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• pp.597-604
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• 2005

The paper describes implementation of smartphone edition based on embedded Linux, which is composed of smartphone middleware and basic applications. Existing smartphone platforms entails loyalty expenses and has difficulties on customization due to the closed policy of their source codes. Although GPE - based on embedded Linux has solved the loyalty issues, other problems are remained unsolved. Since GPE has been designed for relatively large PDA-level devices, applications are generally inoperable under the condition of small LCD size and input methods without touch-screen; the condition is typical limitations of the smartphones. In the implemented smartphone edition of the paper no loyalty is required, because the smartphone edition is based on embedded Linux. It also supports keypad-only operating functionality such as moving between folders or running applications with operations. Besides, it provides more user-friendly environment to use the smartphone editionscreen interfaces and indicatorsto those of the regular cellular phones.