Biomedical subjects

H H Koester

Publications and source records attributed to H H Koester.

3 recordsLinked to original sources

PubMed2001

User performance with speech recognition: a literature review.

The application of speech recognition to the computer access needs of people with disabilities continues to grow, and a greater understanding of user performance with such systems is needed. This article reviews what is known about user performance with speech recognition systems, with a focus on its application to accommodation of physical disability. Although current systems offer the potential of text entry at 150 words per minute, the literature suggests that users actually achieve somewhere between 8 and 30 words per minute. Barriers that may contribute to this gap, such as the costs associated with correcting recognition errors, are reviewed, and directions for future research are proposed. A major need is for additional research involving users who have physical disabilities.

Communication Devices for People with Disabilities↗

PubMed1999

Adaptive one-switch row-column scanning.

Row-column scanning is a very slow method of communication. Options for increasing text entry rate include 1) dynamically changing the configuration of the row-column matrix or 2) using rate-enhancement techniques like word prediction, but evidence suggests that increased cognitive load imposed by these methods on the user can result in little or no improvement in text generation rate. An alternative we are investigating is adapting a system's scan delay during run-time. Our goal is to allow a scanning system to adjust its parameters "on the fly" (as opposed to the current practice of setting parameters during clinical assessments). This paper describes the evolution of a one-switch row-column scanning system that adapts its scan rate based on measurements of user performance. Two experiments have been performed to explore the effects of automatically adapting scan delay on users' text entry rate. Our results indicate that automatic adaptation has the potential to enhance text-entry rate without increasing task complexity.

Adult↗

PubMed1994

Learning and performance of able-bodied individuals using scanning systems with and without word prediction.

This study examines how the cognitive and perceptual loads introduced by a word prediction feature impact learning and performance. Two groups of able-bodied subjects transcribed text using two row-column scanning systems for 10 consecutive trials each. The two systems differed only in that one system had a word prediction feature. Subject groups differed in their order of system use. The results show that, under the conditions of this study, the word prediction system was not substantially more difficult to learn, but it did not yield a statistically significant improvement in text generation rate. This suggests that the cost of using this word prediction system balanced the benefit of the keystroke savings achieved by these subjects. The relationship between keystroke savings, cost in item selection rate, and improvement in text generation rate is explored in order to provide insight into this outcome.

Cognition↗