• 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.

• Journal of Korea Society of Industrial Information Systems
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• v.17 no.5
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• pp.43-51
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• 2012

Smart phones provide variety of functions like world processing, chatting, web browsing, etc. for users. Therefore, efficiency of the keypad that are used in text entry are becoming more important. But, in traditional english mobile keypad, text entry speed is not efficient because simple placement of characters in accordance with the order of characters. In this paper, we propose the improved english keypad for smart phone using the frequency information of english characters and bigram. And, we verified that the proposed keypad is more efficient than other keypads through the experiment.

• Journal of the Ergonomics Society of Korea
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• v.23 no.2
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• pp.105-120
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• 2004

With the new technology and the popularization of mobile phone. the functions and designs of mobile phone have been varied rapidly. However. based on the user's level of familiarity on mobile phone function and knowledge of information technology. the using behaviors of mobile phone. especially between the young users who are well acquainted with the latest function and technology and the over middle-aged users who are relatively not. would be quite different. A survey was conducted to investigate the various using behaviors of mobile phone in different age groups. The total number of six hundred and sixty-seven people from age seventeen to sixty participated in this study. The participants were divided into young group (age between 17 to 29) and the over middle-aged group (age between 40 to 60) to compare the difference group considered design. price. and function of the mobile phone as three important factors. on the other hand. the over middle-aged group considered quality of communication. price and ease of use as three important factors. All the respondents of the young group know how to use the text messaging function. however for the over middle-aged group. 40% of the respondents knows how to use the text messaging function. The over middle-aged group seemed mainly use the mobile phone for voice communication. however the young group had a tendency to communicate each other with short text message rather than through voice conversation. Twenty percentage of young group responded that they had an experience of pain or discomfort at the thumb. the thenar eminence area. or carpus area during pushing the mobile phone keypad. The excessive frequent use of keypad may cause the risk of repetitive strain injury (RSI). The results of this study could provide important information to understand the way of using mobile phone in different age groups. and also could be used to design and market the mobile phone.

• Design & Manufacturing
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• v.11 no.1
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• pp.34-38
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• 2017

Deformation frequently occurring in injection molded products is a phenomenon displayed due to uneven shrinkage distribution and orientation of the whole molded product. Shrinkage deformation is a very serious problem because it causes deformation of the molded article and shortens the performance of the product. In this paper, we are focusing on the warpage of keypad in mobile phone. In other words, we focused on minimizing keypad deformation. In the study, the Taguchi method was applied to find the injection molding conditions that minimize the deformation of the keypad. In the case of this keypad, the main factors influencing the shrinkage deformation were predicted as the melting temperature, coolant temperature and cooling time. In addition, the optimum molding conditions were obtained and the shrinkage strain was minimized. Experiments for the Taguchi method and verification of optimal molding conditions were performed using an injection molding analysis program.

• 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.

• Journal of Korea Game Society
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• v.9 no.2
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• pp.13-22
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• 2009

Recently, mobile games are developed as the various genre and form with the hardware performance improvement and communication network speed increase of the mobile phone. But it shows the limit of the game material to be developed, because the mobile game has to play by using only the keypad handing of the mobile phone. In this research, 'Flip On / Off interface' and 'Microphone interface' were developed in order to utilize the physical device of the mobile phone as the game interface. 'Flip On / Off interface' and 'Microphone interface' have the advantage that there is no need to purchase a device as an additional interface with utilizing the hardware of the mobile phone itself and the progressing of a game is smooth in comparison with the keypad method of the pre-existence mobile game because the interface waiting time for a call response is short. Moreover, by applying to a commercializing game, the developed interface tests, we confirmed an availability at the commercialization inspection standards on mobile phone without the heap memory deficiency phenomenon to be smooth of an operation. Furthermore, in the result of usability evaluation accessability, reliability, and aesthetics were rated as 'high'. The results of this research reveal that the interface environment of the mobile game limited to a keypad will be able to be made with diversification.

• Journal of the Ergonomics Society of Korea
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• v.24 no.1
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• pp.47-53
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• 2005

The purpose of this study was to evaluate performance and subjective satisfaction of mobile phone's interface elements considering the elderly users. First, mobile phone's interface elements were outlined recent foreign and domestic studies. Then, final three mobile phone's interface elements were determined by expert rating, AHP analysis, and questionnaire analysis. Objective and subjective measures were then used to determine the effects of several specific design parameters and aging differences on performance of mobile phones. In this experiment, 38 subjects and 4 independent variables were used to measure task completion time and user's subjective satisfaction. The statistical analyses indicated significant aging differences between older people and younger people in terms of keypad type and bell sound level in performance. Significant aging differences were also found for user subjective satisfaction. It is suggested that some major results from this study be used to develop mobile phone design guidelines that are more usable and accessible for most users, particularly for older users.

• Journal of the Korean Institute of Intelligent Systems
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• v.19 no.6
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• pp.814-820
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• 2009

The arrangement of the general 12-button cellular phone keypad is unified with one or two kind. In general, the several alphabets are arranged in one key. When inputting an English, countries which do not speak English use multi-tap method. We can input next alphabet by pressing key repeatedly. We address the problem of finding multi-tap-based keypad designs which minimize the number of key presses for various case. Genetic algorithms is proposed method for optimal keypad designs. We are to maintain the number of keys, which is ranged from 8 to 12. We also show experimental using non-alphabetically-constrained and alphabetically-constrained arrangement, respectively. Finally, we give improved keypad designs.

• Journal of the Ergonomics Society of Korea
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• v.26 no.3
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• pp.117-124
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• 2007

A few people are frequently using Korean text entry function in the mobile phone. To make matters worse, too many kinds of Korean text entry methods exist in the market, compelling mobile phone users to learn how to input texts all over again, whenever they purchase a new mobile phone. The purpose of this study is to propose a universal design of Korean text entry method for mobile phones. Several experiments and several questionnaire surveys were conducted in order to induce design factors for the universal design. Participants were mobile phone users with the diverse levels of text entry expertise and with the diverse ages. The results of this investigation were identical, irrespective of participants' age and expertise. The efficiency of the text entry method was not more important factor than memorability. The layout of vowels to keypad was preferred to map just 3 strokes to the 3 buttons so that users can make for themselves vowels that they want to input. The preference on the consonants layout was different according to investigation methods. According to the survey, it was preferred that consonants were arranged by alphabet order. However, the result of text entry speed measurement was that the arrangement by alphabet order was not superior to the typical arrangement. Such results may be used to design mobile phones for diverse users.

• 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.