Designing optimum stylus keyboard layout for Turkish language using a decomposition-based heurisitc

Abstract

Due to continuous and revolutionary developments in communication technology; the importance and application areas of mobile devices, which can be sampled by PDA's, hand terminals and 3G cellular phones, are increasing day after day. Owing to physical limitations, generally these devices could only be used by stylus keyboards, which can be typed by stylus, single finger and so on. In this study; data entry by stylus keyboards is analysed from ergonomics view, also the precautions, which should be taken to keep the stylus keyboard users against the cumulative trauma disorders, are explored. A literature survey for the most important of these precautions, optimization of stylus keyboard layout in other languages, is made in detail. Two stylus keyboard layouts; one for the classical longitudinal shaped as QWERTY and the other for square shaped keyboard which is believed to be more efficient, are designed. For layout optimization, a Quadratic Assignment Problem model is established and solved by a newly developed decomposition based and deterministic heuristic. New designed two stylus keyboard layouts are tried to be compared with currently in use layouts for Turkish; F and Turkish Q layouts. Comparisons are made with three tecniques; computer aided simulation by randomly selected Turkish e-texts, estimating the typing speeds of expert users for all layouts by using Fitts‟ Law - a Human Computer Interaction model and finally by plotting learning curves of subjects, by the help of a test package coded for this study, following a laboratory procedure. It is concluded that, new generated longitudinal and square layouts have higher typing speeds and average distance per digraph values compared with standard QWERTY and F layouts.