Objective. Dry electrodes have an advantage over gel-based 'wet' electrodes by providing quicker set-up time for electroencephalography recording; however, the potentially poorer contact can result in noisier recordings. We examine the impact that this may have on brain-computer interface communication and potential approaches for mitigation. Approach. We present a performance comparison of wet and dry electrodes for use with the P300 speller system in both healthy participants and participants with communication disabilities (ALS and PLS), and investigate the potential for a data-driven dynamic data collection algorithm to compensate for the lower signal-to-noise ratio (SNR) in dry systems. Main results. Performance results from sixteen healthy participants obtained in the standard static data collection environment demonstrate a substantial loss in accuracy with the dry system. Using a dynamic stopping algorithm, performance may have been improved by collecting more data in the dry system for ten healthy participants and eight participants with communication disabilities; however, the algorithm did not fully compensate for the lower SNR of the dry system. An analysis of the wet and dry system recordings revealed that delta and theta frequency band power (0.1-4 Hz and 4-8 Hz, respectively) are consistently higher in dry system recordings across participants, indicating that transient and drift artifacts may be an issue for dry systems. Significance. Using dry electrodes is desirable for reduced set-up time; however, this study demonstrates that online performance is significantly poorer than for wet electrodes for users with and without disabilities. We test a new application of dynamic stopping algorithms to compensate for poorer SNR. Dynamic stopping improved dry system performance; however, further signal processing efforts are likely necessary for full mitigation.

Requirements in the development of application-specific integrated circuits (ASICs) continue to increase. This leads to more complexities in handling and processing the requirements, which often causes inconsistencies in the requirments. To better manage the resulting complexities, ASIC development is evolving into a model-based process. This thesis is part of a continuing research into the application and evolution of a model-based process for ASIC development at the Robert Bosch GmbH. It focuses on providing methologies that enable tracing of ASIC requirements and specifications as part of a model-based development process to eliminate inconsistencies in the requirements. The question of what requirements are and, what their traceability means, is defined and analysed in the context of their relationships to models. This thesis applies requirements engineering (RE) practices to the processing of ASIC requirements in a development environment. This environment is defined by availability of tools which are compliant with some standards and technologies. Relying on semi-formal interviews to understand the process in this environment and what stakeholders expect, this thesis applies the standards and technologies with which these tools are compliant to provide methodologies that ensures requirements traceability. Effective traceability methods were proven to be matrices and tables, but for cases of fewer requirements (ten or below), requirement diagrams are also efficient and effective. Furthermore, the development process as a collaborative effort was shown to be enhanced by using the resulting tool-chain, when the defined methodologies are properly followed. This solution was tested on an ASIC concept development project as a case study.

Biomechanics research investigating the knee kinematics of youth participants is very limited. The most accurate method of measuring knee kinematics utilizes invasive procedures such as bone pins. However, various experimental techniques have improved the accuracy of gait kinematic analyses using minimally invasive methods. In this study, gait trials were conducted with two participants between the ages of 11 and 13 to obtain the knee flexion-extension (FE), adduction-abduction (AA) and internal-external (IE) rotation angles of the right knee. The objectives of this study were to (1) conduct pilot experiments with youth participants to test whether any adjustments were necessary in the experimental methods used for adult gait experiments, (2) apply a Triangular Cosserat Point Element (TCPE) analysis for Soft-Tissue Artifact (STA) correction of knee kinematics with youth participants, and (3) develop a code to conduct a Principal Component Analysis (PCA) to find the PCA-defined flexion axis and calculate knee angles with both STA and PCA-correction for youth participants. The kinematic results were analyzed for six gait trials on a participant-specific basis. The TCPE knee angle results were compared between uncorrected angles and another method of STA correction, Procrustes Solution, with a repeated measures ANOVA of the root mean square errors between each group and a post-hoc Tukey test. The PCA-corrected results were analyzed with a repeated measures ANOVA of the FE-AA correlations from a linear regression analysis between TCPE, PS, PCA-TCPE and PCA-PS angles. The results indicated that (1) youth experiments can be conducted with minor changes to experimental methods used for adult gait experiments, (2) TCPE and PS analyses did not yield statistically different knee kinematic results, and (3) PCA-correction did not reduce FE-AA correlations as predicted.

Human motion capture technology is a powerful tool for advancing the understanding of human motion biomechanics (Andriacchi and Alexander, 2000). This is most readily accomplished by applying retroreflective markers to a participant’s skin and tracking the position of the markers during motion. Skin and adipose tissue move independently of the underlying bone during motion creating error known as soft tissue artifact (STA), the primary source of error in human motion capture (Leardini et al., 2005). (Solav et al., 2014) proposed and (Solav et al., 2015) expanded the triangular Cosserat point element (TCPE) method to reduce the effect of STA on derived kinematics through application of a marker cluster analyzed as a set of triangular Cosserat point elements. This method also provides metrics for three different modes of STA. Here the updated TCPE method (Solav et al., 2015) was compared to the established point cluster (PC) method of (Andriacchi et al., 1998) and the marker position error minimizing Procrustes solution (PS) method of (Söderkvist and Wedin, 1993) in two implant-based simulations, providing quantitative measures of error, and standard gait analysis, providing qualitative comparisons of each method’s determined kinematics. Both of these experiments allowed the TCPE method to generate observed STA parameters, informing the efficacy of the simulation. The TCPE method’s performance was similar to the PS method’s in the implant simulations and in standard gait. The PC method’s results seemed to be affected by numerical instability: simulation trial errors were larger and standard gait results were only similar to the other methods’ in general terms. While the PS and TCPE results were comparable, the TCPE method’s physiological basis provided the added benefit of non-rigid behavior quantization through its STA parameters. In this study, these parameters were on the same order of v magnitude between the standard gait experiments and the simulations, suggesting that implant simulations could be valuable substitutes when invasive methods are not available.

Titel:Vilken inverkan kan en artefakt med symboliskt och historiskt laddat värde ha, i syfte att omvrida en företagskultur?  Syftet med denna studie är att undersöka hur människor upplever och förstår ett kul- turellt förändringsinitiativ, utifrån en artefakt med symboliskt och historiskt laddat värde. Detta genom att titta på ett specifikt fall för att i realtid kunna studera hur artefakten påverkar människornas värderingar, föreställningar, innebörder och känslor kopplat till artefakten. Studiens ändamål är att bidra med fördjupad kunskap inom organisationsforskningen och fenomenet företagskultur.  Studien är en explorativ fallstudie vilken genomfördes med hjälp av observationer, semistrukturerade intervjuer samt granskning av fältanteckningar. Organisationsmedarbetare som är direkt involverade i och påverkade av organissationsförändringsinitiativet observerades delvis i sin arbetsmiljö och under intervjuer. Intervjuerna baserades på den artefakt som lett förändringsinitiativet med fokus på organsiationsmedarbetarnas upplevelser och förståelse av artefakten/förändringen. För att analysera empirimassan användes tematisk analys.  Studien har kommit fram till att artefakter som karaktäriseras av gemensamma före- ställningar och positiv attityd kan användas för att kunna omdefiniera grundläggande antaganden och omvrida kulturen. Studiens empiriska fynd visar även att det kan upp- stå en konflikt med att använda en historisk laddad artefakt med starka band till det förflutna. Förklaringen är att symboler är kontextberoende, där den nutida kontexten inte överensstämmer med de kollektiva föreställningarna. De meningsskiljaktigheter som uppstår kan bidra till att försvaga kulturen istället för den goda tanken om att förstärka den. De negativa attityderna kan orsaka splittring, vilket blir svårt för led- ningen att använda i sitt kulturprogram.

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Diffusion Tensor Imaging (DTI) is a magnetic resonance imaging (MRI) technique used to measure in-vivo anisotropic water diffusion. This can give useful information regarding white matter integrity and has the potential to provide important biomarkers in spinal cord injury. One of the largest challenges in DTI of the spinal cord is the presence of metal which causes geometric distortions, signal pile-up, and signal voids. Because most patients with spinal cord injury have some amount of metal hardware implanted for stabilization, it is important to confront issues involving metal as DTI of the spinal cord becomes more widely examined. This study examined the characteristics of metal artifact in DTI images for several spinal surgical implants via imaging of phantoms constructed with implements suspended in agar gel to provide a homogeneous surrounding medium for analysis. A cervical spine phantom implanted with pedicle screws was also used to simulate in-vivo imaging. Optimization of the DTI sequence was also considered using different metal artifact reduction techniques including view-angle-tilting, slice thickness, and field of view size. Minor reduction in metal artifact was achieved using these techniques. The resulting image data shows that imaging near metal may be feasible in some circumstances, particularly when implantation is minimal. Also, using the cervical spine phantom it was shown that it should be possible to acquire DTI data close to the location of metal implants and thus examine DTI values of the injured spinal cord superior to the injury site. / Mechanical Engineering

Studies have shown that modeling errors due to unaccounted for soft-tissue deformations – known as soft-tissue artifact (STA) – can reduce the efficacy and usefulness of musculoskeletal simulations. Recent work has proven that adding degrees of freedom (DOF) to the joint definitions of a musculoskeletal model’s lower limbs can significantly change the prediction of an individual’s kinematics and dynamics while simultaneously improving estimates of their mechanical work. This indicates that additional modeling complexity may mitigate the effects of STA. However, it remains to be determined whether adding DOF to the lower limb joints can impact a model’s satisfaction of Newton’s Second Law of Motion, or whether a specific number of DOF must be incorporated in order to produce the most biomechanically accurate simulations. To investigate these unknowns, I recruited ten subjects of variable body-mass-indices (BMI) and recorded subject walking data at three speeds normalized by Froude number (Fr) using optical motion capture and an instrumented treadmill (eight male, two females; mean ± s.d.; age 21.6 ± 2.87 years; BMI 25.1 ± 5.1). Then, I added DOF to the lower limb joints of OpenSim’s 23 DOF lower body and torso model until it minimized the magnitude of the pelvis residual forces and moments for a single, representative subject trial (BMI = 24.0, Fr = 0.15). These artificial residual forces and moments are applied at the pelvis to maintain the model’s orientation in space by satisfying Newton’s Second Law. Finally, I simulated all 30 trials with both the original and the edited model and observed how the biomechanical predictions of the two models differed over the range of subject BMIs and walking speeds. After applying both the original and the edited model to the entire data set, I found that the edited model resulted in statistically lower (α = 0.05) residual forces and moments in four of the six directions. Then, after investigating the impact of changes in BMI and Froude number on these residual reductions, I found that two of the six directions exhibited statistically significant correlations with Froude number while none of the six possessed correlations with BMI. Therefore, adding DOF to the lower limb joints can improve a model’s dynamic consistency and combat the effects of STA, and simulations of higher speed behaviors may benefit more from additional DOF. For BMI, it remains to be determined if a higher BMI indicates greater potential for residual reduction, but it was shown that this method of tuning the model for one representative subject was agnostic to BMI. Overall, the method of tuning the model for one representative subject was found to be quite limited. There were multiple subject trials for which reduced residuals corresponded to drastic changes in kinematic and dynamic estimates until they were no longer representative of normal human walking. Therefore, it is possible to improve dynamic consistency by adding DOF to the lower limb joints. But, for biomechanically relevant estimates to be consistently preserved and soft-tissue artifact to be completely minimized, subject-specific model tuning is likely necessary. / Mechanical Engineering

This dissertation entitled, Exploring Design Thinking for Instructional Practice, is situated in the cognitive rigor of design thinking instructional practice and engineering design-based capstone courses. The content of the instructional practice connects with educators employing a wide range of intellectual activities or cognitive tasks in formulating their curriculum. Key attributes of design thinking were identified through a focused literature review with an emphasis on theoretical propositions applicable to instructional practice. This dissertation contains two manuscripts: (a) an exploration of the theoretical literature related to design thinking explicating implications for instructional practice, and (b) a case study involving a small, purposive, sample of undergraduate faculty members teaching engineering design-based courses with findings broadly applicable to design processes in college curricula. The faculty participants in the case study were educators at a large, public, research-intensive university in the southeastern region of the United States. The data analyses involved triangulation of semi-structured interviews conducted with faculty participants and their design-based course materials, including syllabi and lesson plan materials. The study's thematic findings were not tied to engineering but rather course design, design process, and course management. The findings show the utility of artifact creation for learning with understanding for everyone, not just engineers and other traditional designers. Overall, the dissertation contributes to pedagogy that promotes student-centered engagement for learning with understanding. It recommends design thinking instructional practice for inclusion in designing and making artifacts of constructed knowledge for learning with understanding engagements across the academy. / Doctor of Philosophy / This dissertation entitled, Exploring Design Thinking for Instructional Practice, integrates a wide range of intellectual activities also referred to as cognitive tasks of student-centered design thinking activities. In this dissertation, these tasks are useful for tackling problems that are not well-defined, such as, open-ended, real-world problems. Examples of this pedagogy are useful for educators considering and/or implementing design thinking in their curricula. This dissertation contains two manuscripts: (a) an exploration of the theoretical literature related to design thinking from theory to artifact making, and (b) a case study involving undergraduate faculty members teaching design thinking in design-based courses. The study's faculty participants were educators teaching engineering capstone courses at a large, public, research university in the southeastern region of the United States. Their students design and make solutions for open-ended, real-world problems that are not in textbooks and do not have "right" answers. The study's data collection phase involved interviews with the faculty participants and course materials (syllabi, lesson plan materials, handouts, and course websites). Data analysis produced three robust themes: course design, design process, and course management. These themes suggest that a design thinking instructional practice belies perceptions that design thinking is tied exclusively to engineering and other traditional design disciplines. The findings suggest that design thinking pedagogy engages students in creation of artifacts, learning with understanding, hands-on experiential learning in iterations, use of productivity tools, teamwork, and new starting points when outcomes do not meet expectations. Overall, the findings suggest design thinking pedagogy promotes student-centered design thinking activities.