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published_or_final_version / Electrical and Electronic Engineering / Doctoral / Doctor of Philosophy

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The analysis of electromyographic (EMG) signals detected during muscle contraction provides important information to aid in the diagnosis and characterization of neuromuscular disorders. One important analysis measures neuromuscular jitter, which is the variability of the time intervals between two muscle fibre potentials (MFPs) belonging to the same motor unit over a set of discharges. Conventionally, neuromuscular jitter is measured using single fibre (SF) EMG techniques, which can identify individual MFPs by using a SF needle electrode. However, SF electrodes are expensive, very sensitive to needle movement and not easy to operate in practise. <br /><br /> A method is studied in this thesis for automatically measuring neuromuscular jitter in motor unit potentials (MUP), it measures jitter using routine EMG techniques, which detect MUPs using a concentric needle (CN) electrode. The method is based on the detection of near MFP contributions, which correspond to individual muscle fibre contributions to MUPs, and the identification of individual MFP pairs. The method was evaluated using simulated EMG data. After an EMG signal is decomposed into MUP trains, a second-order differentiator, McGill filter, is applied to detect near MFP contributions to MUPs. Then, using nearest neighbour clustering and minimum spanning tree algorithms, the sets of available filtered MUPs can be selected and individual MFPs can be identified according to the features of their shapes. Finally, individual MFP pairs are selected and neuromuscular jitter is measured. <br /><br /> Using the McGill filter, near MFP contributions to detected CN MUPs can be consistently detected across an ensemble of successive firings of a motor unit. The method is an extension of the work Sheng Ma, compared to previous works, more efficient algorithms are used which have demonstrated acceptable performance, and which can consistently measure neuromuscular jitter in a variety of EMG signals.

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Embodied interactions and learning have garnered a lot of interest among researchers and game designers in past years, especially with the recent development of consumer-level body sensory devices like the Microsoft Kinect. This study focused on examining whether embodied interactions, enabled by the Kinect, could lead to greater knowledge acquisition compared to traditional mouse-based interactions working with STEM-related (numeric systems) and language-related (Chinese character) learning in a virtual learning environment for adult learners. Embodied cognition, body movements and learning, cognitive processing theories were discussed as a theoretical framework for this study. A 3D virtual learning environment was designed, in which learners could interact with the instructional materials through either their body movements, or a mouse. The study utilized an experimental, two-group, pre- and posttest design. The experimental group used the Kinect-enabled embodied interactions and the control group used the traditional mouse-based interactions during an on-site learning intervention. Fifty-three adult participants were recruited and randomly assigned to either the experimental group or the control group. Scores from immediate posttest and delayed posttest between the two groups were compared with ANCOVA using pretest score as the covariate. Statistical results informed that embodied interactions enabled by the Kinect facilitated learning in numeric systems and Chinese characters for the participating adult learners. However, compared with the mouse interaction, the embodied interaction enabled by the Kinect did not lead to significantly better knowledge retention and application results in both immediate posttest and delayed posttest in numeric systems learning. And for Chinese characters learning, compared with the mouse interaction, the embodied interaction enabled by the Kinect did not lead to significantly better knowledge retention results in the immediate posttest either, but achieved significantly better performance in the delayed posttest. The study outcome implies that Kinect-based embodied interactions do not necessarily lead to better learning performances over traditional mouse-based interactions for adult learners. The performances may depend on subject areas, and at what time learners’ knowledge retrieval were evaluated. When designing computer-mediated learning modules, researchers and practitioners should not only look at the new technology and novel approaches to interacting with the computers, but also take the subject areas, learners, and time issues into consideration as well. / A Dissertation submitted to the Department of Educational Psychology and Learning Systems in partial fulfillment of the Doctor of Philosophy. / Summer Semester 2017. / June 23, 2017. / Embodied Interactions, Kinect, Learning / Includes bibliographical references. / Fengfeng Ke, Professor Directing Dissertation; Gordon Erlebacher, University Representative; Valerie J. Shute, Committee Member; Allan C. Jeong, Committee Member.

Use of real, authentic whole tasks in training has been the focus of current instructional theories and practical educational approaches (Merrill, 2002; Reigeluth, 1999; van Merrienboer & Kirschner, 2001). However, teaching authentic tasks poses challenges because of the complex nature of these tasks and the limited capacity of working memory. To overcome these challenges, van Merrienboer and Paas (1996) proposed the Four Components of Instructional Design (4C/ID) model to teach authentic complex skills without overloading the working memory. The model has four components: learning tasks, supportive information, procedural information, and part-task practice. Basing the 4C/ID model, Kester et al. (2001) suggest that presenting supportive information before and supportive information during the task practice would lead to more effective and efficient instruction than presenting the procedural information before and supportive during the practice tasks. Even though the ‘supportive before, procedural during’ information presentation format has been hypothesized to be superior to the other information presentation formats (i.e., supportive before, procedural before; supportive during, procedural before; supportive during, procedural during), not all empirical studies and findings confirm this particular hypothesis (Kester et al., 2001; Kester, Kirschner, & van Merrienboer, 2004a; Kester, Kirschner, & van Merrienboer, 2006). To explain these conflicting findings, differences in the degree to which learners were allowed or not allowed to review information presented prior to the practice session (learner control) was tested in this study. The purposes of this study were to (a) investigate the effects of the information presentation format on practice tasks, posttest, transfer test, mental effort, instructional efficiency, and performance efficiency, (b) investigate the effects of the learner control on practice tasks, posttest, transfer test, mental effort, instructional efficiency, and performance efficiency, (c) reveal the interaction effects, if there is, between the information presentation format and learner control on the practice tasks, posttest, transfer test, mental effort, instructional efficiency, and performance efficiency, and (d) assess the students’ attitudes toward the instructional modules. To accomplish these purposes, the study used 2x2 (n=4) factorial design to compare the effects of presenting supportive information before procedural information during the practice tasks with learner control (PS_L); presenting supportive information before procedural information during the practice tasks with system control (PS_S); presenting supportive information before procedural information during the practice with learner control (SP_L); and presenting supportive information before procedural information during the practice tasks with system control (SP_S). The dependent variables were practice task scores, post-test, transfer test, mental effort, time-on-task, instructional efficiency, and performance efficiency. The students completed a demographic survey, two modules with practice tasks, post-test, transfer test, and an attitude survey. The learner control group was enabled the students to go back and review supportive information during task practice within the entire course while the system control group were not able to go back to review the procedural information they receive prior to starting the task practice. Overall, ninety-hundred participants from a southern city in the United States are assigned to one of four conditions. The results revealed that students in the PS group performed significantly better on the practice tasks and posttest than students in the SP group; students in the learner control group performed significantly better than students in the system control group on the practice tasks and posttest. Even though no interaction found between the timing of information presentation format and learner control on the dependent variables, the post hoc results showed that presenting procedural information before the practice tasks with learner control led to a greater performance on the practice tasks, posttest, and instructional efficiency. Regarding to the post study learners’ attitude survey, the SP_L group showed more positive attitude toward the instruction than the other groups even though the PS_L group performed significantly better than the other groups. Overall, the study found some evidence that presenting procedural information before practice task was more effective and efficient than presenting supportive information before practice task when given learner control. In cases where it is possible to provide learner control (such as an online self-paced instructions), the findings in this study suggest that instructors use the PS presentation format. Considering the limitations of this study, the findings in this study are not conclusive. / A Dissertation submitted to the Department of Educational Psychology and Learning Systems in partial fulfillment of the Doctor of Philosophy. / Summer Semester 2017. / July 17, 2017. / cognitive load theory, four components of instructional design, instructional design, just in time model, learner control, timing of information presentation / Includes bibliographical references. / Allan C. Jeong, Professor Directing Dissertation; Gordon Erlebacher, University Representative; Vanessa P. Dennen, Committee Member; James Klein, Committee Member.