A Thumb Stroke-Based Virtual Keyboard for Sight-Free Text Entry on Touch-Screen Mobile Phones

The use of QWERTY on most of the current mobile devices for text entry usually requires users’ full visual attention and both hands, which is not always possible due to situational or physical impairments of users. Prior research has shown that users prefer to hold and interact with a mobile device with a single hand when possible, which is challenging and poorly supported by current mobile devices. We propose a novel thumb-stroke based keyboard called ThumbStroke, which can support both sight-free and one-handed text entry on touch-screen mobile devices. Selecting a character for text entry via ThumbStroke completely relies on the directions of thumb movements at anywhere on a device screen. We evaluated ThumbStroke through a longitudinal lab experiment including 20 sessions with 13 participants. ThumbStroke shows advantages in typing accuracy and user perceptions in comparison to Escape and QWERTY and results in faster typing speed than QWERTY for sight-free text entry

Improving the Accuracy of Mobile Touchscreen QWERTY Keyboards

In this thesis we explore alternative keyboard layouts in hopes of finding one that increases the accuracy of text input on mobile touchscreen devices. In particular, we investigate if a single swap of 2 keys can significantly improve accuracy on mobile touchscreen QWERTY keyboards. We do so by carefully considering the placement of keys, exploiting a specific vulnerability that occurs within a keyboard layout, namely, that the placement of particular keys next to others may be increasing errors when typing. We simulate the act of typing on a mobile touchscreen QWERTY keyboard, beginning with modeling the typographical errors that can occur when doing so. We then construct a simple autocorrector using Bayesian methods, describing how we can autocorrect user input and evaluate the ability of the keyboard to output the correct text. Then, using our models, we provide methods of testing and define a metric, the WAR rating, which provides us a way of comparing the accuracy of a keyboard layout. After running our tests on all 325 2-key swap layouts against the original QWERTY layout, we show that there exists more than one 2-key swap that increases the accuracy of the current QWERTY layout, and that the best 2-key swap is i ↔ t, increasing accuracy by nearly 0.18 percent