Work-related musculoskeletal disorders (WMSDs) cost US industries billions annually and reduce quality of life for those afflicted. Passive exoskeletons (EXOs) have emerged as a potential intervention to reduce worker exposures to WMSD risk factors. As EXO adoption is rising, EXO manufacturers are designing and producing new EXOs in accordance with growing demand. However, there are no standardized EXO evaluation protocols and EXO use recommendations, due in part to insufficient information on the reliability of EXO evaluation measures. The purpose of this thesis was to quantify the reliability of common EXO evaluation measures, using both traditional approaches a more advanced statistical approach (i.e., Generalizability Theory), while also identifying potential effects of EXO type, work task, and individual differences. This work used data from a recently completed EXO evaluation study, conducted in Virginia Tech's Occupational Ergonomics and Biomechanics Lab. Forty-two total participants completed simulated occupational tasks, in two separate experimental sessions on different days, while using an arm-support EXO (ASE) and a back-support EXO (BSE). Several outcome measures reached excellent within-session reliability within four trials for many tasks considered. Between-session reliability levels were lower than within-session levels, with outcome measures reaching moderate-to-good reliability for most tasks. Interindividual differences accounted for the largest proportion of variance for measurement reliability, followed by the experimental session. For all tasks, outcome measures reached excellent dependability levels, with many achieving excellent levels within five total trials. Inconsistencies observed in between-session reliability levels and dependability levels suggest that additional training and EXO familiarity may affect measurement reliability of outcome measures differently for some tasks, unique to each EXO type. These discrepancies emphasize the importance for additional research into this topic. Overall, the current findings indicate that many of the commonly used EXO evaluation measures are reliable and dependable within five trials and one experimental session, providing a potential foundation for standardized EXO assessment protocols. / Master of Science / Work-related musculoskeletal disorders (WMSDs) are a substantial economic burden and impair the quality of life for affected workers. Passive exoskeletons (EXOs), which use springs or elastic material to distribute the load placed on workers during manual labor, are a possible solution to reduce worker exposure to WMSD risk factors. EXO adoption is rising, but there are no standardized procedures to test the effectiveness of EXOs or standardized recommendations for EXO use. The purpose of this thesis was to determine the reliability of EXO evaluation measures commonly used in prior research, using both traditional reliability calculation methods alongside a more advanced method (i.e., Generalizability Theory). Data from a recently completed study were used, which were collected from 42 participants in two separate experimental sessions on two different days. Participants completed tasks intended to simulate manual work, using either an arm-support exoskeleton – which supported their upper arms during relevant tasks, or a back-support exoskeleton – which supported their lower back during relevant tasks. Many of the tasks and outcome measures reached excellent reliability within four repetitions in a single day. When examining reliability of evaluations across days, we found reliability levels were lower than levels obtained from a single day. All tasks and outcome measures reached excellent dependability levels, with many requiring only five trials to reach excellent levels. Reliability increased with the number of trials in an EXO evaluation experiment. Moreover, our results revealed that the EXO type being used and the biological sex of a participant both influence reliability, but individual participant differences had the greatest effect on measurement reliability. This research reveals possible experimental conditions required for reliable, efficient, and cost-effective EXO research, facilitating the development of a standardized EXO evaluation protocol.

An across-subjects, post-test only design was used in two experiments to assess the impact of interspersing additional math problems (i.e., briefer problems and/or longer problems) among target math problems on students’ persistence when completing computer-delivered math multiplication problems. In Experiment 1, high school students who worked only target problems completed 32% more target problems and worked 22% longer than those who had briefer problems interspersed. Problem completion rates were significantly higher for those who had briefer problems interspersed. These results suggest that altering assignments by interspersing additional, briefer discrete tasks does not always enhance, and in some instances may hinder academic responding. Stimulus preference and within-trial contrast effects provided possible explanations for these results and indicated that interspersing longer problems could, perhaps, cause students to increase persistence. Experiment 2 was designed to replicate Experiment 1 and extend this line of research by investigating the stimulus preference and within-trial contrast hypothesizes. To increase the number of participants and allow for the evaluation of three conditions, college students served as participants for Experiment 2. In Experiment 2, no significant differences among groups (i.e., control group with only target problems, experimental group with brief problems interspersed, and experimental group with long problems interspersed) were found in the amount of time before college students quit working or in their problem completion accuracy levels. Interspersal of the long problems significantly reduced the number of target problems completed. The results failed to support stimulus preference or within-trial contrast theories. Discussion focuses on theoretical and applied implications related to the additive interspersal procedure, the discrete task completion hypothesis, and the delay reduction hypothesis. Applied implications suggest that educators avoid interspersing longer discrete tasks and exercise caution when interspersing brief tasks.

BACKGROUND: Prospective memory difficulties are one of the most common deficits following acquired brain injury. The application of smartphones as a compensatory aid to these difficulties has shown promising results. This study looked to investigate these benefits further. OBJECTIVE: The aims of this study were to investigate whether receipt of reminder prompts through ones smartphone improved completion of pre-planned tasks, in addition to whether it also had secondary implications for participant's wellbeing, confidence, independent functioning, and whether it had any impact on caregiver strain levels. METHOD: This study used an ABAB case series design with mild to moderate acquired brain injury. Task completion rates were monitored across four phases (prompts vs. no prompts). Quantitative questionnaires were administered pre, post and at three months follow up to assess coping with memory difficulties. A qualitative questionnaire explored the perceived impact of the smartphone reminders on everyday functioning, in addition to a 3 month follow up measure assessing attrition rates in smartphone use. RESULTS: Visual inspection analysis suggested greater task completion when reminders were provided. The quantitative questionnaires showed increased use of a Smartphone as reminder device post intervention and at follow up. A basic thematic analysis highlighted a perception that the smartphone system increased task completion, confidence in coping with memory demands, supported emotional wellbeing and reduced dependence on others. As a memory aid it was also less stigmatising and promoted dignity. The three month follow up questionnaire highlighted that all participants continued to use their smartphone as a memory aid. CONCLUSIONS: Use of a smartphone as a memory compensation aid may improve completion of pre-set tasks. Secondary benefits may include increased confidence in coping with memory demands, reduced dependence on others for help, and reduced anxiety or frustration around forgetting.

Educators of students with moderate and severe intellectual disabilities face a significant challenge in preparing their students while in school to function, acquire, and maintain skills that would facilitate successful performance in the workforce while in supported and/or independent employment after graduation. The field of special education still debates about the best way to teach students with moderate intellectual disabilities, the best setting for their instruction and the best instructional schedule. The current research investigated the effectiveness and efficiency of three instructional schedules in the skill acquisition and generalization of two-way radio usage to report task completion by high school students with moderate intellectual disabilities. The instructional schedules investigated were: (a) community-based instruction only (CBI), (b) community based instruction plus simulated instruction in the classroom-same day (CBISC) and (c) simulated instruction in the classroom only (SICO). A Multiple Probe Design across participants with intermittent probe trials within each instructional group, and an added generalization phase (Horner & Baer, 1978; Tawney & Gast, 1984; Alberto & Troutman, 2003) was employed in this study. Nine high school students with moderate intellectual disabilities, three in each instructional schedule, were taught to use a two-way radio to report task completion. The results of the study revealed that the CBI instructional schedule was the overall most efficient instructional schedule for skill acquisition. Two of the CBI participants required the least number of trials to learn to use a two-way radio to report task completion. The second most efficient schedule was the CBISC and the least efficient instructional schedule was the SICO. Based on Mean scores, learning efficiency appeared to be greater for the participants in the CBI and CBISC instructional schedule. These participants required the least number of intrusive prompts. Results indicated that the SICO instructional scheduled was more efficient for only one participant. This participant only required verbal prompts for acquisition of the skill. However, participant one on the SICO instructional schedule required the most intrusive prompts of all participants across groups. For generalization, the CBISC instructional schedule appeared to be the most effective. In this schedule, the two participants that concluded the study generalized the skill across three novel settings with 100% accuracy. The SICO schedule, also had two participants generalized the skill across three novel settings; however, one participant in that group failed to generalize the skill in two settings. The CBI instructional schedule appeared to be the least effective for skill generalization in this study. In this schedule, only one participant generalized the skill in all three novel settings.

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Traditionella arbetsrelaterade stressorer har sedan drygt ett decennium kompletterats med ambivalens kring arbetsuppgifters färdigställande (”task completion ambiguity”) och ambivalens kring arbetsresultatets kvalitet (”task quality ambiguity”) som konstaterats ha samband med arbetstrivsel. Föreliggande enkätstudie syftade till att undersöka hur sambanden mellan dessa faktorer ser ut bland sångare. Utöver arbetstrivsel undersöktes också samband med upplevd press från andra och sig själv samt psykisk ohälsa, rösthälsa och fysisk hälsa. Totalt deltog 74 svenska operasångare. Sambandsanalyserna visade att arbetstrivsel inte förklaras av någon av studievariablerna. Ambivalens kring arbetsuppgifters färdigställande samvarierade bara med ambivalens kring arbetsresultatets kvalitet medan press och psykisk ohälsa samvarierade med alla studievariabler utom ambivalens kring arbetsuppgifters färdigställande. Resultaten avseende operasångare skiljer sig därmed från tidigare studier på andra yrkesgrupper vilket kan hänga samman med att sångare upplever andra faktorer som viktigare för sin trivsel och arbetsrelaterade hälsa.

With the advent of the modern technological age, a plethora of electronic tools and devices are available in numbers as never before. While beneficial and ex-ceedingly useful, these electronic devices require users to operate them. When designing systems capable of observing and acting upon an environment, the number of devices can become unmanageable. Previously, middleware sys-tems were designed for large-scale computational systems. However, by apply-ing similar concepts and distributing logic to autonomous agents residing on the devices, a new paradigm in distributed systems research on lightweight de-vices is conceivable. Therefore, this research focuses upon the development of a lightweight middleware that can reside on small devices enabling the capabil-ity for these devices to act autonomously. In this research, analyses determined the most advantageous methods for solving this problem. Defining a set of requirements for the necessary middle-ware as well as assumptions for the environment and system in which it would operate achieved a proper research focus. By utilizing concepts already in ex-istence such as peer-to-peer networking and distributed hash tables, devices in this system could communicate effectively and efficiently. Furthermore, creat-ing custom algorithms for communicating with other devices, and collaborating on task assignments achieved an approach to solving the consensus problem in real time. The resulting middleware solution allowed a demonstration to prove the effi-cacy. Using three devices capable of observing the environment and acting up-on it, two tests highlighted the capabilities of the consensus-finding mechanism as well as the ability of the devices to respond to changes in the environment autonomously.

This study employed the theoretical framework of Albert Bandura???s social cognitive theory, to investigate how differing levels of self-efficacy impact on both the type and degree of self-regulatory behaviour employed by the students when composing music in a high school music program. The literature review revealed an abundance of related research suggesting a strong relationship between self-efficacy and self-regulated behaviour in the ???core??? academic domains of education. In contrast, there was no specific research found that had examined self-efficacy and self-regulation in the context of students composing music. An independent school in Sydney served as the research site, with sixty-eight students of varied year levels and musical experience participating in the study. Students used stand alone computers, the software ???Cubase??? and MIDI keyboards as they completed a task that involved creating an original piece of music in a genre of their own choice, over a series of four composition sessions. A mixed methodology was employed to determine if the influence of the students??? self-efficacy beliefs upon their self-regulation in a creative activity were consistent with existing research. Data were collected using a mixture of weekly measures and self-report scales, combined with a variety of questionnaires, logs, tally sheets and interviews. Eight variables, including the self-regulatory sub-processes of goal setting-strategic planning, intrinsic motivation, goal orientation, task expectation, time on task, task completion, monitoring were analysed together with an additional variable, defined as creative ability, to determine if evidence could be found of a relationship between self-efficacy and these specific behaviours while composing. The results suggest that the pre-task (Week 1) measure of self-efficacy was closely associated with the students??? use of the eight self-regulatory dimensions as well as their perceived level of creative ability. Weekly self-efficacy measures also suggested that students??? employ self-regulated sub-processes proportionally to their respective levels of self-efficacy. Importantly, the more efficacious students employed a wider and more sophisticated repertoire of self-regulated behaviour when composing in contrast to the less efficacious students. Self-efficacy was also identified as a key factor amongst students who were initially identified as being naive self-regulators, but who through the duration of the task, modified their behaviour to become more skilful self-regulators. Throughout the study, the consistent level of interaction between self-efficacy and the use of self-regulated behaviours were aligned with findings in the core ???academic??? disciplines of education.

This study employed the theoretical framework of Albert Bandura???s social cognitive theory, to investigate how differing levels of self-efficacy impact on both the type and degree of self-regulatory behaviour employed by the students when composing music in a high school music program. The literature review revealed an abundance of related research suggesting a strong relationship between self-efficacy and self-regulated behaviour in the ???core??? academic domains of education. In contrast, there was no specific research found that had examined self-efficacy and self-regulation in the context of students composing music. An independent school in Sydney served as the research site, with sixty-eight students of varied year levels and musical experience participating in the study. Students used stand alone computers, the software ???Cubase??? and MIDI keyboards as they completed a task that involved creating an original piece of music in a genre of their own choice, over a series of four composition sessions. A mixed methodology was employed to determine if the influence of the students??? self-efficacy beliefs upon their self-regulation in a creative activity were consistent with existing research. Data were collected using a mixture of weekly measures and self-report scales, combined with a variety of questionnaires, logs, tally sheets and interviews. Eight variables, including the self-regulatory sub-processes of goal setting-strategic planning, intrinsic motivation, goal orientation, task expectation, time on task, task completion, monitoring were analysed together with an additional variable, defined as creative ability, to determine if evidence could be found of a relationship between self-efficacy and these specific behaviours while composing. The results suggest that the pre-task (Week 1) measure of self-efficacy was closely associated with the students??? use of the eight self-regulatory dimensions as well as their perceived level of creative ability. Weekly self-efficacy measures also suggested that students??? employ self-regulated sub-processes proportionally to their respective levels of self-efficacy. Importantly, the more efficacious students employed a wider and more sophisticated repertoire of self-regulated behaviour when composing in contrast to the less efficacious students. Self-efficacy was also identified as a key factor amongst students who were initially identified as being naive self-regulators, but who through the duration of the task, modified their behaviour to become more skilful self-regulators. Throughout the study, the consistent level of interaction between self-efficacy and the use of self-regulated behaviours were aligned with findings in the core ???academic??? disciplines of education.

The main body of this thesis consists of six appended papers. In the  first two, different  cooperative surveillance problems are considered. The second two consider different aspects of the trajectory planning problem, while the last two deal with observer design for mobile robotic and Euler-Lagrange systems respectively.In Papers A and B,  a combinatorial optimization based framework to cooperative surveillance missions using multiple Unmanned Ground Vehicles (UGVs) is proposed. In particular, Paper A  considers the the Minimum Time UGV Surveillance Problem (MTUSP) while Paper B treats the Connectivity Constrained UGV Surveillance Problem (CUSP). The minimum time formulation is the following. Given a set of surveillance UGVs and a polyhedral area, find waypoint-paths for all UGVs such that every point of the area is visible from  a point on a waypoint-path and such that the time for executing the search in parallel is minimized.  The connectivity constrained formulation  extends the MTUSP by additionally requiring the induced information graph to be  kept recurrently connected  at the time instants when the UGVs  perform the surveillance mission.  In these two papers, the NP-hardness of  both these problems are shown and decomposition techniques are proposed that allow us to find an approximative solution efficiently in an algorithmic manner.Paper C addresses the problem of designing a real time, high performance trajectory planner for an aerial vehicle that uses information about terrain and enemy threats, to fly low and avoid radar exposure on the way to a given target. The high-level framework augments Receding Horizon Control (RHC) with a graph based terminal cost that captures the global characteristics of the environment.  An important issue with RHC is to make sure that the greedy, short term optimization does not lead to long term problems, which in our case boils down to two things: not getting into situations where a collision is unavoidable, and making sure that the destination is actually reached. Hence, the main contribution of this paper is to present a trajectory planner with provable safety and task completion properties. Direct methods for trajectory optimization are traditionally based on a priori temporal discretization and collocation methods. In Paper D, the problem of adaptive node distribution is formulated as a constrained optimization problem, which is to be included in the underlying nonlinear mathematical programming problem. The benefits of utilizing the suggested method for  online  trajectory optimization are illustrated by a missile guidance example.In Paper E, the problem of active observer design for an important class of non-uniformly observable systems, namely mobile robotic systems, is considered. The set of feasible configurations and the set of output flow equivalent states are defined. It is shown that the inter-relation between these two sets may serve as the basis for design of active observers. The proposed observer design methodology is illustrated by considering a  unicycle robot model, equipped with a set of range-measuring sensors. Finally, in Paper F, a geometrically intrinsic observer for Euler-Lagrange systems is defined and analyzed. This observer is a generalization of the observer proposed by Aghannan and Rouchon. Their contractivity result is reproduced and complemented  by  a proof  that the region of contraction is infinitely thin. Moreover, assuming a priori bounds on the velocities, convergence of the observer is shown by means of Lyapunov's direct method in the case of configuration manifolds with constant curvature. / QC 20100622 / TAIS, AURES