Pain from the musculoskeletal system is very common in the modern society. Chronic musculoskeletal pain syndromes causes not only individual suffering but also dysfunctions of movements and postural control, as large costs for the society. In spite of significant efforts, there is a shortage of knowledge on effective prevention, diagnoses and rehabilitation of different chronic musculoskeletal pain syndromes. The general aims of this thesis was to investigate the predictive value of physical, sociodemographic, and psychosocial-behavioural variables for pain reduction after multimodal rehabilitation in patients with chronic low back or neck pain, and to develop and evaluate tests for objective and quantitative evaluation of characteristic sensorimotor disturbances in chronic neck pain. Logistic regression models revealed that unchanged pain intensity could be predicted with good precision while reduced pain intensity after rehabilitation was poorly predicted by the baseline variables. Altered pain intensity in chronic low back pain was predicted by high pain intensity, low levels of pain severity and high affective distress, while reduced pain intensity for patients with chronic neck pain were predicted by high endurance, low age, high pain intensity, low need of being social along with optimistic attitudes on how the pain will interfere with daily life, and few vegetative symptoms. One of the conclusions was that objective measures of specific sensorimotor disturbances should improve the precision by which treatment-induced effects can be assessed and predicted. A study was designed to objectively and quantitatively evaluate a large numbers of different sensorimotor characteristics in a small group of patients with chronic neck pain of different aetiology (whiplash-related and insidious). Kinematic data was recorded during different motor tasks, involving cervical rotations, arm movements and standing. In comparison to a group of asymptomatic control subjects, patients with chronic neck pain was characterised by slower movements, poor balance, reduced cervical stability during perturbations, altered smoothness of movement (jerk index), and reduced movement precision (variable error and variability in range of motion). The sensorimotor variables velocity of arm movements and cervical stability, could correctly classified nearly 90% of the subjects as having chronic neck pain or being asymptomatic. There was a large diversity of sensorimotor disturbances among the individual patients. This was confirmed in a regression model that failed to separate the groups insidious neck pain (sensitivity 44%) and WAD (sensitivity 67%). By investigating associations between the different sensorimotor variables, close relations was found between the repositioning acuity and variability in range of motion, and between standing balance and cervical stability/ standing balance during perturbation. These two groups of variables were only weakly related to each other and to smoothness of movement and movement velocity. The results indicate that chronic neck pain is characterised by specific sensorimotor deficits, and that there are common pathophysiological mechanisms in chronic neck pain of different aetiology. However, the lack of associations between several sensorimotor disturbances indicates that different mechanisms are involved. The thesis indicates that objective sensorimotor tests should be used to improve the quality of functional assessments in chronic neck pain. Methods that objectively and quantitatively measure e.g. movement precision, balance and cervical stability are also needed in order to evaluate current treatment methods and to develop new rehabilitation programs for specific sensorimotor deficits.

Le processus de fabrication des pièces usinées arrive à maturité concernant la fabrication assistée par ordinateur et la maîtrise du procédé d'usinage. Aujourd'hui, les perspectives d'améliorations importantes sont liées à l'optimisation de la commande numérique et de ses interactions avec le reste du processus de fabrication. L'objectif de cette thèse est donc de maîtriser les briques de base de la commande numérique pour optimiser le processus d'usinage 5 axes grande vitesse des surfaces complexes. La création d'une commande numérique ouverte nécessite le développement des algorithmes qui transforment le programme d'usinage en consignes échantillonnées pour les axes de la machine. La première partie des travaux consiste à rendre la géométrie suffisamment continue notamment pour les trajets interpolés linéairement en 5 axes qui présentent des discontinuités en tangence. Ensuite, l'interpolation temporelle du trajet crée la trajectoire d'usinage respectant les contraintes cinématiques et en particulier le jerk de chacun des 5 axes de la machine. L'implémentation matérielle de ces algorithmes permet de piloter une machine d'usinage grande vitesse 5 axes avec une commande numérique ouverte. Ainsi, les verrous technologiques associés aux commandes numériques industrielles sont levés et la chaîne numérique est entièrement contrôlée de la CFAO jusqu'au déplacement des axes. La maîtrise complète de la commande numérique offre la possibilité de définir exactement le trajet d'usinage à partir de la CAO sans introduire les écarts géométriques inhérents aux formats de description standards. L'interpolation de la trajectoire d'usinage directement sur la surface à usiner améliore de manière significative la qualité et la productivité de l'usinage des surfaces complexes. La commande numérique PREMIUM-OpenCNC permet la validation expérimentale de ces travaux et ouvre de nombreuses autres voies d'amélioration du processus de fabrication.

This diploma thesis deals with the application of three methods to limit resonances of critical frequencies and with a description of their influence on speed control loop of linear drive. The first damping method involved the use of an electro-magnetic tilger attached to the structure of stand on critical locations. The second method involved the use of a jerk decoupling in linear direct drives. A Cauer-filter that was activated in the controller of linear motor was added to both methods. The appropriate measuring technique for these frequencies was systematically analysed and selected. Further in this document models of mechanical structure and controlling are described. Matlab®/Simulink® software was used for the data processing and the modification of models according to the real structure.

This thesis studies real-time reference ramping of human input for remotely operated vehicles and its effect on system control, power usage, and user experience. The implementation, testing, and evaluation were done on the remotely operated Blueye Pioneer underwater drone. The developed method uses minimum jerk trajectories for transitioning between varying target velocities with a constant end jerk target. It has a low computational cost and runs in real-time on the Blueye Pioneer underwater drone. The presented method produces a well-defined reference with continuous position, velocity, and acceleration states that can be used in the feedback loop. Experiments and simulations show that the method produces a smoother and more predictable motion path for the user. The motions are better suited for video recordings and remote navigation, compared to the direct usage of human input velocity. The smoother reference reduces the controller tracking error, the peak control input, and the energy usage. The introduced acceleration reference state is used for feedforward control on the system. It improves the feeling of controlling the drone by reducing the system lag, the position tracking error, and the rise time for velocity changes.

The purpose of this thesis was to observe psychological, physiological, and performance changes to determine when two high-level weightlifters were peaked for a major competition. We addressed this purpose by conducting a two-part case study series with one USA international level female and one USA national level male weightlifter. Both athletes were considered to be peaked on competition day. The results support our hypothesis that jumping performance would be peaked on competition day corresponding with an increased recovery and decreased stress state. However, contrary to our hypothesis, each athlete exhibited small decreases in muscle size leading into the competition relative to baseline values. Further, changes in inflammatory markers were inconsistent for each athlete and were not reduced as hypothesized. Based on our findings, this investigation supports the use of overreaching and tapering for individual strength-power athletes providing insight into underlying psychological and physiological basis for observed changes in performance.

No description available.

As the frontiers and futures of work evolve, humans and machines will begin to share a more cooperative working space where collaboration occurs freely amongst the constituent members. To this end, it is then necessary to determine how information should flow amongst team members to allow for the efficient sharing and accurate interpretation of information between humans and machines. Shared situation awareness (SSA), the degree to which individuals can access and interpret information from sources other than themselves, is a useful framework from which to build design guidelines for the aforementioned information exchange. In this work, we present initial Augmented/virtual reality (AR/VR) design principles for shared situation awareness that can help designers both (1) design efficacious interfaces based on these fundamental principles, and (2) evaluate the effectiveness of candidate interface designs based on measurement tools we created via a scoping literature review. This work achieves these goals with focused studies that 1) show the importance of SSA in augmented reality-supported tasks, 2) describe design guidelines and measurement tools necessary to support SSA, and 3) validate the guidelines and measurement tools with a targeted user study that employs an SSA-derived AR interface to confirm the guidelines distilled from the literature review. / Doctor of Philosophy / As the way in which humans work and play changes, people and machines will need to work together in shared spaces where team members rely on one another to complete goals. To make this interaction happen in ways that benefit both humans and machines, we will need to figure out the best way for information to flow between team members, including both humans and machines. Shared situation awareness (SSA) is a helpful concept that allows us to understand how people can get and understand information from sources other than themselves. In this research, we present some basic ideas for designing augmented reality (AR) tools that help people work together in better ways using SSA as a guiding framework. These ideas can help designers (1) create AR tools that work well based on these basic ideas and (2) test how well different interface designs work using specially developed tools we made. We completed user studies to (1) show how important SSA is when using AR to help with tasks, (2) explain the design ideas and tools needed to support SSA, and (3) test these ideas and tools with a study that uses an AR tool, based on SSA, to make sure the guidelines we got from reading other research are correct.

Cette thèse porte sur la modélisation et vérification des signatures en ligne. La première partie a pour thème principal la modélisation biomécanique des mouvements de la main. Un modèle basé sur le critère de Minimum de Secousse (MS) a été choisi parmi plusieurs théories du contrôle moteur. Ensuite, le problème de la segmentation des trajectoires en traits qui correspondent au modèle cinématique choisi a été étudié, ce qui a conduit à la mise au point d'une méthode de segmentation itérative. Le choix du modèle et de la méthode de segmentation sont basé sur le compromis entre la qualité de reconstruction et la compression. Dans la deuxième partie, le modèle polynomial issu du critère de MS est volontairement dégradé. Les zéros non-Réels des polynômes sont jetés et les effets de cette dégradation sont étudiés dans une perspective de vérification biométrique. Cette dégradation est équivalente à la technique connue sous le nom d’Infinity Clipping, initialement appliqué à des signaux de parole. Pour les signatures en ligne, comme pour la parole, la préservation de l'information essentielle a été observée sur des tâches de vérification de signature. En fait, en utilisant seulement la distance de Levenshtein sur la représentation dégradée, un taux d'erreur comparable à ceux des méthodes plus élaborées a été obtenu. En outre, la représentation symbolique issue de l’Infinity Clipping permet d’établir une relation conceptuelle entre le nombre de segments obtenus par la segmentation itératif basée sur le MS et la complexité de Lempel-Ziv. Cette relation est potentiellement utile pour l'analyse des signatures en ligne et pour l’amélioration des systèmes de reconnaissance / This thesis deals with the modelling and verification of online signatures. The first part has as main theme the biomechanical modelling of hand movements associated to the signing gesture. A model based on the Minimum Jerk (MJ) criterion was chosen amongst the several available motor control theories. Next, the problem of signature trajectory segmentation into strokes that better fit the chosen kinematic model is studied, leading to the development of an iterative segmentation method. Both the choice of the model and the segmentation method are strongly based on the tradeoff between reconstruction quality and compression. On the second part, the polynomial model provided by the MJ criterion is intentionally degraded. The non-Real zeroes of the polynomials are discarded and the effects of this degradation are studied from a biometric verification perspective. This degradation is equivalent to the signal processing technique known as Infinity Clipping, originally applied to speech signals. On signatures, as for speech, the preservation of essential information was observed on signature verification tasks. As a matter of fact, using only the Levenshtein distance over the infinitely clipped representation, verification error rates comparable to those of more elaborate methods were obtained. Furthermore, the symbolic representation yielded by the infinity clipping technique allows for a conceptual relationship between the number of polynomial segments obtained through the Minimum Jerk-Based iterative segmentation and the Lempel-Ziv complexity. This relationship is potentially useful for the analysis of online signature signals and the improvement of recognition systems

Thesis (MScPhysio (Physiotherapy))--University of Stellenbosch, 2009. / The ability to walk has been rated by stroke patients as one of the most important goals of their rehabilitation. Knee control is a key element in normal gait. Currently, treatment options aimed at improving poor knee control in stroke patients are often costly, need specialised equipment and have poor patient compliance. The purpose of the current study was to assess whether medial patellar taping could improve knee control in stroke patients. Gait speed, dynamic standing balance, knee alignment and whether the subjects experienced any subjective stabilising effect on the knee after taping were tested. Twenty subjects diagnosed with hemiplegia after a stroke served as their own controls in a repeated measures experimental study. Results indicated that dynamic standing balance as tested by the Step Test (p=0.063) and the Timed-up-and-go test (p=0.099) (Wilcoxon test) showed marginal improvement after taping. This improvement in dynamic standing balance may indicate that neuro-motor control and/or eccentric knee control had improved. There was no change in walking speed and knee alignment as tested by change in the Q-angle (Wilcoxon test). However, a decrease in the Q-angle correlated with an improvement in dynamic standing balance as tested by the Step Test (p=0.029) (Spearman‟s test). Participants with decreased Q-angles after taping possibly had better knee alignment and were more willing to accept weight on their affected leg indicating a change in quadriceps activation. No change in walking speed (p=0.351) (Wilcoxon test) before and after taping may indicate that there was no change in the magnitude of contraction and/or concentric activity in the quadriceps muscle. Thirty percent of the participants reported a subjective change in knee stability after taping. Subjective change did not, however, significantly correlate with either of the balance tests, walking speed or Q-angle measurements. The possibility that medial patellar taping may be useful in treating poor knee control in stroke patients during dynamic balance activities should be investigated further.

<p>The transmission is probably the drivetrain component with the greatest impact on driveability of an automatic transmission equipped vehicle. Since the driver only has an indirect influence on the gear shift timing, except for situations like kick-down accelerations, it is desirable to improve shift quality as perceived by the driver. However, improving shift quality is a problem normally diametrically opposed to minimizing transmission clutch energy dissipation. The latter has a great impact on transmission lifetime, and has to be defined and taken into consideration along with the notion of shift quality. The main focus of this thesis is the modeling of a drivetrain of an automatic transmission vehicle, and the implementation in MatLab/Simulink, including the first to second gear upshift. The resulting plant based on the derived equations is validated using data from a test vehicle equipped with a torque sensor located at the transmission output shaft. The shaft torque is more or less proportional to the driveline jerk, and hence of great interest for control purposes. Control strategies are discussed and a PID controller structure is developed to control the first to second gear upshift, as opposed to the traditional open-loop upshift control. Furthermore, the proposed controller structure uses the transmission output torque and the differential speed of the engaging clutch as inputs, to control the clutch pressure and the engine output torque, respectively. The structure is unsophisticated and transparent compared to other approaches, but shows great theoretical results in terms of improved shift quality and decreased clutch wear.</p>