• 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.