The Effect of Tactile and Audio Feedback in Handheld Mobile Text Entry

Effects of tactile and audio feedback are examined in the context of touchscreen and mobile use. Prior experimental research is graphically summarized by task type (handheld text entry, tabletop text entry, non-text input), tactile feedback type (active, passive), and significant findings, revealing a research gap evaluating passive tactile feedback in handheld text entry (a.k.a. texting ). A passive custom tactile overlay is evaluated in a new experiment wherein 24 participants perform a handheld text entry task on an iPhone under four tactile and audio feedback conditions with measures of text entry speed and accuracy. Results indicate audio feedback produces better performance, while the tactile overlay degrades performance, consistent with reviewed literature. Contrary to previous findings, the combined feedback condition did not produce improved performance. Findings are discussed in light of skill-based behavior and feed-forward control principles described by Gibson (1966) and Rasmussen (1983)

Making Spatial Information Accessible on Touchscreens for Users who are Blind and Visually Impaired

Touchscreens have become a de facto standard of input for mobile devices as they most optimally use the limited input and output space that is imposed by their form factor. In recent years, people who are blind and visually impaired have been increasing their usage of smartphones and touchscreens. Although basic access is available, there are still many accessibility issues left to deal with in order to bring full inclusion to this population. One of the important challenges lies in accessing and creating of spatial information on touchscreens. The work presented here provides three new techniques, using three different modalities, for accessing spatial information on touchscreens. The first system makes geometry and diagram creation accessible on a touchscreen through the use of text-to-speech and gestural input. This first study is informed by a qualitative study of how people who are blind and visually impaired currently access and create graphs and diagrams. The second system makes directions through maps accessible using multiple vibration sensors without any sound or visual output. The third system investigates the use of binaural sound on a touchscreen to make various types of applications accessible such as physics simulations, astronomy, and video games

Optimizing Human Performance in Mobile Text Entry

Although text entry on mobile phones is abundant, research strives to achieve desktop typing performance "on the go". But how can researchers evaluate new and existing mobile text entry techniques? How can they ensure that evaluations are conducted in a consistent manner that facilitates comparison? What forms of input are possible on a mobile device? Do the audio and haptic feedback options with most touchscreen keyboards affect performance? What influences users' preference for one feedback or another? Can rearranging the characters and keys of a keyboard improve performance? This dissertation answers these questions and more. The developed TEMA software allows researchers to evaluate mobile text entry methods in an easy, detailed, and consistent manner. Many in academia and industry have adopted it. TEMA was used to evaluate a typical QWERTY keyboard with multiple options for audio and haptic feedback. Though feedback did not have a significant effect on performance, a survey revealed that users' choice of feedback is influenced by social and technical factors. Another study using TEMA showed that novice users entered text faster using a tapping technique than with a gesture or handwriting technique. This motivated rearranging the keys and characters to create a new keyboard, MIME, that would provide better performance for expert users. Data on character frequency and key selection times were gathered and used to design MIME. A longitudinal user study using TEMA revealed an entry speed of 17 wpm and a total error rate of 1.7% for MIME, compared to 23 wpm and 5.2% for QWERTY. Although MIME's entry speed did not surpass QWERTY's during the study, it is projected to do so after twelve hours of practice. MIME's error rate was consistently low and significantly lower than QWERTY's. In addition, participants found MIME more comfortable to use, with some reporting hand soreness after using QWERTY for extended periods

Musical Haptics

Haptic Musical Instruments; Haptic Psychophysics; Interface Design and Evaluation; User Experience; Musical Performanc

Target and Spacing Sizes for Smartphone User Interfaces for Older Adults: Design Patterns Based on an Evaluation with Users

The use of smartphones is becoming widespread among all sectors of the population. However, developers and designers do not have access to guidance in designing for specific audiences such as older adults. This study investigated optimal target sizes, and spacing sizes between targets, for smartphones user interfaces intended for older adults. Two independent variables were studied – target sizes and spacing between targets – for two common smartphone gestures – tap and swipe. Dependent variables were accuracy rates, task completion times, and participants’ subjective preferences. 40 older adults recruited from several daycare centers participated in both tasks and a post-session questionnaire. The recommendations drawn from the authors’ research support two interaction design patterns relative to touch target sizes for older adults, and are presented in this paper

Predicting and Reducing the Impact of Errors in Character-Based Text Entry

This dissertation focuses on the effect of errors in character-based text entry techniques. The effect of errors is targeted from theoretical, behavioral, and practical standpoints. This document starts with a review of the existing literature. It then presents results of a user study that investigated the effect of different error correction conditions on popular text entry performance metrics. Results showed that the way errors are handled has a significant effect on all frequently used error metrics. The outcomes also provided an understanding of how users notice and correct errors. Building on this, the dissertation then presents a new high-level and method-agnostic model for predicting the cost of error correction with a given text entry technique. Unlike the existing models, it accounts for both human and system factors and is general enough to be used with most character-based techniques. A user study verified the model through measuring the effects of a faulty keyboard on text entry performance. Subsequently, the work then explores the potential user adaptation to a gesture recognizer’s misrecognitions in two user studies. Results revealed that users gradually adapt to misrecognition errors by replacing the erroneous gestures with alternative ones, if available. Also, users adapt to a frequently misrecognized gesture faster if it occurs more frequently than the other error-prone gestures. Finally, this work presents a new hybrid approach to simulate pressure detection on standard touchscreens. The new approach combines the existing touch-point- and time-based methods. Results of two user studies showed that it can simulate pressure detection more reliably for at least two pressure levels: regular (~1 N) and extra (~3 N). Then, a new pressure-based text entry technique is presented that does not require tapping outside the virtual keyboard to reject an incorrect or unwanted prediction. Instead, the technique requires users to apply extra pressure for the tap on the next target key. The performance of the new technique was compared with the conventional technique in a user study. Results showed that for inputting short English phrases with 10% non-dictionary words, the new technique increases entry speed by 9% and decreases error rates by 25%. Also, most users (83%) favor the new technique over the conventional one. Together, the research presented in this dissertation gives more insight into on how errors affect text entry and also presents improved text entry methods

Target and Spacing Sizes for Smartphone User Interfaces for Older Adults: Design Patterns Based on an Evaluation with Users

The use of smartphones is becoming widespread among all sectors of the population. However, developers and designers do not have access to guidance in designing for specific audiences such as older adults. This study investigated optimal target sizes, and spacing sizes between targets, for smartphones user interfaces intended for older adults. Two independent variables were studied – target sizes and spacing between targets – for two common smartphone gestures – tap and swipe. Dependent variables were accuracy rates, task completion times, and participants’ subjective preferences. 40 older adults recruited from several daycare centers participated in both tasks and a post-session questionnaire. The recommendations drawn from the authors’ research support two interaction design patterns relative to touch target sizes for older adults, and are presented in this paper

Eignung von virtueller Physik und Touch-Gesten in Touchscreen-Benutzerschnittstellen für kritische Aufgaben

The goal of this reasearch was to examine if modern touch screen interaction concepts that are established on consumer electronic devices like smartphones can be used in time-critical and safety-critical use cases like for machine control or healthcare appliances. Several prevalent interaction concepts with and without touch gestures and virtual physics were tested experimentally in common use cases to assess their efficiency, error rate and user satisfaction during task completion. Based on the results, design recommendations for list scrolling and horizontal dialog navigation are given.Das Ziel dieser Forschungsarbeit war es zu untersuchen, ob moderne Touchscreen-Interaktionskonzepte, die auf Consumer-Electronic-Geräten wie Smartphones etabliert sind, für zeit- und sicherheitskritische Anwendungsfälle wie Maschinensteuerung und Medizingeräte geeignet sind. Mehrere gebräuchliche Interaktionskonzepte mit und ohne Touch-Gesten und virtueller Physik wurden in häufigen Anwendungsfällen experimentell auf ihre Effizienz, Fehlerrate und Nutzerzufriedenheit bei der Aufgabenlösung untersucht. Basierend auf den Resultaten werden Empfehlungen für das Scrollen in Listen und dem horizontalen Navigieren in mehrseitigen Software-Dialogen ausgesprochen