Doctoral Degrees (Computer Science and Informatics)
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Browsing Doctoral Degrees (Computer Science and Informatics) by Author "Blignaut, P. J."
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Item Open Access Enhancing the user experience for a word processor application through vision and voice(University of the Free State, 2011) Beelders, Tanya René; Blignaut, P. J.English: Multimodal interfaces may herald a significant improvement on current GUIs which have been commonplace until now. It is also possible that a multimodal interface could provide a more intuitive and natural means of interaction which, simultaneously, negates the reliance on traditional, manual means of interaction. Eye gaze and speech are common components of natural human-human communication and were proposed for use in a multimodal interface for a popular word processor for the purposes of this study. In order for a combination of eye gaze and speech to be a viable interface for a word processor, it must provide a means of text entry and facilitate editing and formatting of the document contents. For the purposes of this study a simple speech grammar was used to activate common word processing tasks, as well as for selection of text and navigation through a document. For text entry, an onscreen keyboard was provided, the keys of which could be pressed by looking at the desired key and then uttering an acceptable verbal command. These functionalities were provided in an adapted Microsoft Word 2007® to increase the customisability and possibly the usability of the word processor interface and to provide alternative means of interaction. The proposed interaction techniques also had to be able to execute typical mouse actions, such as point-and-click. The usability of eye gaze and speech was determined using longitudinal user testing and a set of tasks specific to the functionality. Results indicated that the use of a gravitational well increased the usability of the speech and eye gaze combination when used for pointing-and-clicking. The use of a magnification tool did not increase the usability of the interaction technique. The gravitational well did, however, result in more incorrect clicks due to natural human behaviour and the ease of target acquisition afforded by the gravitational well. However, participants learnt how to use the interaction technique over the course of time, although the mouse remained the superior pointing device. Speech commands were found to be as usable, or even more usable, than the keyboard and mouse for editing and selection purposes, although navigation was hindered to some extent. For text entry purposes, the keyboard far surpasses eye gaze and speech in terms of performance as an input method as it is both faster and results in fewer errors than eye gaze and speech. However, even though the participants were required to complete a number of sessions and a number of text entry tasks per session, more practice may be required for using eye gaze and speech for text entry. Subjectively, participants felt comfortable with the multimodal interface and also indicated that they felt improvement as they progressed through their sessions. Observations of the participants also indicated that as time passed, the participants became more adept at using the multimodal interface for all necessary interactions. In conclusion, eye gaze and speech can be used instead of a pointing device and speech commands are recommended for use within a word processor in order to accomplish common tasks. For the purposes of text entry, more practice is advocated before a recommendation can be made. Together with progress in hardware development and availability, this multimodal interface may allow the word processor to further exploit emerging technologies and be a forerunner in the use of multimodal interfaces in other applications.Item Open Access Using eye-tracking to assess the application of divisibility rules when dividing a multi-digit divident by a single digit divisor(University of the Free State, 2017-09) Potgieter, Pieter Henri; Blignaut, P. J.English: The Department of Basic Education in South Africa has identified factorisation as a problem area in Mathematics for Grade 9 learners. Establishing the foundation for factorisation begins at earlier grades. If learners know the divisibility rules, they can help them to determine the factors of numbers. The divisibility rules are presented to learners in Grade 5 for the first time. When a true/false question is used to assess learners' ability to determine whether a dividend is divisible by a certain divisor, the teacher has no insight in the learners’ reasoning because he or she is only in possession of the final answer, which could be correct or incorrect. If the answer is correct, the teacher does not know if the learner (i) guessed the answer, (ii) correctly applied the divisibility rule, or (iii) incorrectly applied the divisibility rule. To improve the credibility of the assessment, learners can be requested to provide a reason for their answer. However, if the reason is correct, the teacher still does not know whether the learners correctly applied the divisibility rule – regardless of whether the answer is correct or not. A pre-post experiment design was used to investigate the effect of revision on the performance of learners and also the difference in gaze behaviour of learners before and after revision of divisibility rules. About 1000 learners from Grade 4 to Grade 7 of two schools were assessed by means of a paper-based assessment on their knowledge of the divisibility rules before and after revision. The gaze behaviour of 155 learners was also recorded before and after revision. It was found that revision had an impact on learner performance per divisor for nearly all grades that participated in the test for both schools. The gaze behaviour was measured as the percentage of fixation time on the digits of the dividend. It was found that revision had an effect on the gaze behaviour for learners who indicated the reason incorrectly before revision and the answer and reason correctly after revision. However, revision did not have an impact on the gaze behaviour of learners who indicated the answer and reason correctly before and after revision. It was found that the correctness of the answer did not have an impact on the gaze behaviour (except for divisor 6) for learners who indicated the reason correctly. However, revision had an impact on the gaze behaviour for learners who indicated the answer incorrectly and reason correctly before revision, as well as for learners who had both the answer and reason correctly after revision for divisor 6. This infers that eye-tracking can be used to determine whether the divisibility rule was applied correctly or incorrectly. Eye-tracking also revealed that learners who did not know the divisibility rules, only inspected the last two digits of the dividend before indicating their answer. The study suggests that when a teacher has access to the learner’s answer, reason and gaze behaviour, he or she will be in a position to identify if the learner (i) guessed the answer, (ii) applied the divisibility rule correctly, (iii) applied the divisibility rule correctly but made mental calculation errors, or (iv) applied the divisibility rule incorrectly. An instrument is proposed that can be used by teachers to assess learners on divisibility rules where learners only have to indicate whether a dividend is divisible by a divisor. Eye-tracking will predict whether the learner knows the divisibility rule. For 85% of learners who provided the correct answer, their gaze behaviour corresponded with the reason provided. The study concluded, therefore, that eye-tracking can, to a large extent, correctly identify whether learners, who indicated correctly if a dividend is divisible by a certain single digit divisor, applied the divisibility rules correctly.