Heidi Horstmann Koester

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This paper presents a variety of outcomes data from 24 experienced users of automatic speech recognition (ASR) as a means of computer access. To assess usage and satisfaction, we conducted an in-person survey interview. For those participants who had a choice of computer input methods, 48% reported using ASR for 25% or less of their computer tasks, while(More)
We designed and evaluated an agent that recommends a pointing device gain for a given user, with mixed success. 12 participants with physical impairments used the Input Device Agent (IDA), to determine a recommended gain based on their performance over a series of target acquisition trials. IDA recommended a gain other than the Windows default for 9 of 12(More)
A keystroke-level model of user performance was developed to predict the improvement in text generation rate with a word prediction system relative to letters-only typing. Two sets of model simulations were tested against the actual performance of able-bodied and spinal cord injured subjects. For Model 1A, user parameter values were determined independently(More)
Automatic adaptation has the potential to enhance the performance of a wide variety of assistive technologies. This paper describes two adaptive assistive technologies: (1) a "smart wheelchair" that selects its operating mode based on current task requirements and (2) a row-colunm scanning keyboard that changes its scanning rate to conform to the(More)
Single-switch scanning is a technique used by some individuals for spoken and/or written communication. We developed a method for adjusting the settings in a single-switch scanning interface to increase a user's text entry rate (TER). We evaluated that method with nine individuals who use single-switch scanning to communicate. Text entry rates improved by(More)
Fourteen individuals with various motor impairments performed a series of text entry exercises. Performance measures were collected which indicate overall performance (speed and error rate) and classification of errors. Such performance metrics could be useful in assessing the computer access skills of clients, and recommending software, hardware, or(More)
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