An integer programming approach to optimize typing methods on smartphones

Today, smartphones are extensively used for different purposes such as text messaging, emails, browsing the Internet, and even creating and editing documents. As a result, touchscreen keyboards have become one of the dominant textentry methods. Finding an optimal typing method for smartphones not only increases typing speed but also reduces finger fatigue and other health risks. In this paper, an integer programming model is developed to determine the optimal typing method for virtual keyboards on smartphones with the objective of minimizing finger movement time. The model is based on Fitts' law to predict finger movement time, digram linguistic tables for the relative frequencies of key transitions in common English, and the 7^th basic typing phenomenon (also known as the alternate-hand advantage). Six different commonly used typing methods on touchscreen keyboards for smartphones are presented and comparisons are drawn in order to determine the optimal method that minimizes total typing time. The paper also compares the performance of the touchscreen keyboard on two popular smartphones in the market.