Optimization Method of a Japanese Keypad Location for Flick Input on a Smartphone

Abstract

This paper proposes an optimization method of a Japanese keypad location in a smartphone to improve its usability for flick input. This design is based on (i) electromyogram (EMG) measurements in flicking keys on a full-size keypad, (ii) a calculation of percent maximum voluntary contraction (%MVC) from the EMG data and its approximation with a response surface, and (iii) formulation of an optimum keypad location problem and its solution by an optimization technique. This paper demonstrates an application and ascertains the validity of the proposed method by a usability test based on comfort, accuracy, and speed.