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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
431

Terminal Behavioral Modeling of Electric Machines for Real-time Emulation and System-level Analysis

Nazari, Arash 20 September 2022 (has links)
Stability and sustainability of operation of interconnected power converter systems has been an important focus of study in the field of power electronics and power systems. With ever-increasing application of electrical machines by means of electrification of vehicles, airplanes and shipboards, detailed study of the relating dynamics is very important to ensure the proper implementation and stable behavior of the overall system. In this work, the application of the black box approach study of the power converters has been expanded to the electrical machines. Using this modeling method, it is possible of have accurate behavior of electrical and mechanical terminals of the machine without the detailed information about the internal structure of the machine, material characteristics or topology of the machine. Instead, accurate model of electrical and mechanical terminals of the machine are achieved by measuring specific frequency responses of the machine to distinguish dynamic relation of the various electrical and mechanical quantities of the machine. The directly measured frequency responses, are coupled with the dynamics of the source and load in the electrical and mechanical terminals of the machine thus in order to decoupled the described couplings a mathematical process is used that results in decoupling of the controller and drive on the electrical side and the dynamics of the mechanical load and mechanical shaft at the mechanical terminal of the machine. Resulting model is the linear time invariant representation of the electrical machine at a specific operating point. Additionally, this work represents the application of this modeling method for accurate measurement of internal parameters of the machine such as inductances and mechanical inertia and characterization of the mechanical shaft coupler. Resulting unterminated model of the machine is a very important matter of information for system integrators and electrical and mechanical designs related to the application of the machine, to ensure the stable and sustainable operation of the machine. This work for the first time, represents the experimental implementation of this terminal behavioral modeling method for studying electrical machines as well as describes some of the practical limitations of this methodology. By incorporating and integrating a combination of commercially available devices such as frequency response analyzer, Hardware-In-The-Loop (HIL), Power-Hardware-In-The-Loop (PHIL), a test setup has been developed that is capable of control, operate and study arbitrary frame small-signal related measurements required for terminal behavioral study of the electrical machines. Resulting model of the machine that has been extracted from this modeling method is then used to compare in time domain with the real machine in the case of transient change in the mechanical load on the shaft to discover the validity of this modeling procedure. / Master of Science / According to the data from the International Energy Agency, around half of the electricity used globally is consumed by electric motors. Moreover, the growth in the electrical vehicle industry will increase their application even further, hence the development of high-fidelity models of electric machines for real-time emulation, system-level analyses, and stability studies still stands out as an important and needed research focus. New modeling concepts that go beyond the standard industry practice can be used at the design and integration stage to ensure the stable behavior of the overall system. Furthermore, convenient testing and identification pressures can help ensure the long-term operation of the system. Aligned with this trend, this thesis is studying permanent magnet synchronous machines (PMSM) using small-signal terminal-behavioral three-port networks. Having such a behavioral model of the machine available provides many opportunities for system integrators, and even enables an in-situ system observation and stability assessment at both the machine's electrical and mechanical interfaces. This capability can undoubtedly be of high importance in practice, as it is offering new insights into dynamic interactions of the electro-mechanical systems, the governor or turbine control design in ships, aircrafts, electrical vehicles, and even large synchronous machines in power plants. A so-called characterization testbed has been built that combines Hardware-In-The-Loop (HIL) and Power-Hardware-In-The-Loop (PHIL) environments, with sensor-interface boards that are used to properly scale measured signals for machine control. The Frequency-Response-Analyzer is used to sweep the proper electrical or mechanical terminal of the machine by perturbing the proper control signal within the machine controller running in PHIL and reading d-q currents, voltages, torque, and speed variables whose dynamic ratios are then obtained without the need for interrupting the normal operation of the electrical machine. The capability of acquiring such a detailed model of the machine while the machine is in operation is an important benefit of this modeling method, in comparison to the conventional identification methods widely applied in the industry. The resulting model is a linearized time invariant representation of the electrical machine at a specific operating point of interest, and can be used by system integrators to ensure the stability of the system using well known stability assessment methodologies. Furthermore, this modeling strategy has been experimentally verified for the first time on electrical machines, and the resulting model has been compared with the transient behavior of the machine in the presence of a step change in the mechanical load of the machine.
432

Applications of Motor Variability for Assessing Repetitive Occupational Tasks

Sedighi, Alireza 07 June 2017 (has links)
The human body has substantial kinetic and kinematic degrees-of-freedoms, so redundant solutions are available for the central nervous system (CNS) to perform a repetitive task. Due to these redundancies, inherent variations exist in human movement, called motor variability (MV). Current evidence suggests that MV can be beneficial, and that there is an inverse association between MV and risk of injury. To better understand how the CNS manipulates MV to reduce injury risks, we investigated the effects of individual differences, task-relevant aspects, and psychological factors as modifiers of MV. Earlier work found that experienced workers adapted more stable movements than novices in repetitive lifting tasks. To expand on this, we quantified how MV differs between experienced workers and novices in different lifting conditions (i.e., lifting asymmetry and fatigue). Three different measures (cycle-to-cycle SD, sample entropy, and the goal equivalent manifold) were used to quantify MV. In a symmetric lifting task, experienced workers had more constrained movement than novices, and experienced workers exhibited more consistent behavior in the asymmetric condition. Novices constrained their movements, and could not maintain the same level of variability in the asymmetric condition. We concluded that experienced workers adapt stable or flexible strategies depending on task difficulty. In a prolonged lifting task, both groups increased their MV to adapt to fatigue; they particularly increased variability in a direction that had no effects on their main task goal. Developing fatigue also makes it difficult for individuals maintain the main goal. Based on these results, we conclude that increasing variability is an adaptive strategy in response to fatigue. We also assessed variability in gait parameters to compare gait adaptability using a head-worn display (HWD) compared with head-down displays for visual information presentation. An effective strategy we observed for performing a cognitive task successfully during walking was to increase gait variability in the goal direction. In addition, we found that head-up walking had smaller effects on MV, suggesting that HWDs are a promising technology to reduce adverse events during gait (e.g., falls). In summary, these results suggest that MV can be a useful indicator for evaluating some occupational injury risks. / Ph. D. / Whenever an individual performs a repetitive task, we can observe variations in their movement patterns. The magnitude of these variations, which are called motor variability, may be related to the risk of injury. To better understand this relationships, we investigated how different risk factors affect the patterns of human movement. In two studies, we compared movement patterns of experienced workers and novices in a repetitive lifting task. In a simple, brief lifting task, novices had more variations in their movement patterns. However, novices did not have the same level of variation in asymmetric lifting tasks, and constrained their movement more than experienced workers. Experienced workers, though, had a similar level of variation in both simple and more difficult lifting conditions. We concluded that whether stable or flexible movement pattern are used depends on task difficulty and the level of experience. In a longer-duration lifting task, both experienced workers and novices increased variations in their movement patterns over time, and we believe that these increases were an adaptation to fatigue. In a third study, we investigated the differences between variations in walking pattern when people use different types of information display (i.e., paper, cellphone, and smart glasses). Using smart glasses had a smaller effect on movement patterns, suggesting that this technology is potentially is safer than other types of display. In summary, these results suggest that studying the variations in human movement patterns can be a useful indicator to evaluate the risk of injury.
433

Skillnader i prestation vid dual task-tester mellan individer med och utan främre korsbandsskada / Differences in performance in dual task-tests between individuals with and without anterior cruciate ligament injury

Laguna Ek, Anton, Elm, Anton January 2024 (has links)
Introduktion: Efter en främre korsbandsskada och korsbandsrekonstruktion (ACLR) drabbas många av en upprepad skada. En anledning kan vara att en ACL-skada medför neuroplastiska förändringar som kan ge ett ökat neurokognitivt beroende. Det här kan i sin tur innebära en nedsatt kapacitet att utföra motoriska uppgifter med samtidiga sekundära uppgifter – även kallat dual task-förmåga. Graden av neurokognitivt beroende mäts ofta genom dual task-tester (DT-tester) där den s.k. DT-kostnaden då kan komma att avslöjas. Syfte: Att undersöka om individer med ACLR visar större DT-kostnad än oskadade individer under hopptest med sekundära kognitiva uppgifter. Därtill att undersöka om självskattad psykologisk beredskap har ett samband med dual task-kostnaden hos individer med ACLR. Metod: 20 personer med ACLR och 20 personer utan knäbesvär utförde drop jump-test med sekundära kognitiva uppgifter (DT-testet). Både motoriska och kognitiva prestationer utvärderades. Gruppernas prestationer jämfördes mellan varandra med oberoende T-test. För kartläggning av psykologisk beredskap, omfattande känslor, självförtroende och riskbedömning användes enkäten Anterior Cruciate Ligament Return to Sport after Injury (ACL-RSI). För att bedöma sambandet mellan ACL-gruppens prestationer på DT-testet och totalpoängen på ACL-RSI användes Pearson’s korrelationskoefficient. Resultat: De oberoende t-testen bekräftade att ACL-gruppen presterade sämre än kontrollgruppen på DT-testet. I den motoriska uppgiften hade ACL-gruppen medelvärdet 85 % och kontrollgruppen 94,6 %. I den kognitiva uppgiften hade ACL-gruppen medelvärdet 66.7 % och kontrollgruppen 82,9%. Det uppvisades ett svagt positivt men ej signifikant samband mellan ACL-gruppens prestationer på DT-testet och ACL-RSIs totalpoäng. Konklusion: ACL-gruppen presterade sämre än kontrollgruppen på DT-test med sekundär kognitiv utmaning. Däremot visade sig psykologisk beredskap inte influera ACL-gruppens prestation på DT-testet. Resultaten styrker hypotesen att individer med ACLR har svårare att utföra DT-test med sekundära kognitiva utmaningar, men inte hypotesen att lägre psykologisk beredskap negativt påverkar deras prestationer.
434

Extracting muscle synergies from human steady and unsteady locomotion: methods and experiments

Santuz, Alessandro 23 August 2018 (has links)
Die Notwendigkeit, sich über unebene, sich ständig verändernde Gelände zu bewegen, gehört zu unserem täglichen Leben. Das zentrale Nervensystem muss daher eine erhöhte Menge an Information integrieren, um mit der Unvorhersehbarkeit äußerer Störungen zurechtkommen zu können. Die Folge dieser erhöhten Beanspruchung könnte eine flexible Kombination der modularen Organisation von Bewegungssteuerung sein. Auf Kosten der Genauigkeit der Bewegung wäre es so möglich, dass das System reagiert, indem es die Robustheit (Fähigkeit mit Fehlern umzugehen) seiner Steuerung erhöht. Jedoch sind die Strategien, die das zentrale Nervensystem zur Organisation der Bewegung verwendet, immer noch schlecht verstanden. Eine Möglichkeit besteht darin, dass Bewegungen zustande kommen durch eine kleine Anzahl linear kombinierter Aktivierungsmuster (Muskelsynergien). Unter den verschiedenen Möglichkeiten der Bewegungsstörung sind das Weglassen von Schuhen und die Verwendung von unebenen Oberflächen zwei gebräuchliche Optionen. In einem ersten Schritt habe ich eine gründliche Analyse der Methoden durchgeführt, die nützlich sind für a) die Auswertung von raumzeitlichen Gangparametern mithilfe von Daten der plantaren Druckverteilung und b) die Extraktion von Muskelsynergien mittels nicht-negativer Matrixfaktorisierung. Anschließend habe ich die modulare Organisation von c) beschut und barfuß Laufen und d) Laufband Gehen und Laufen über ebener und unebener Oberfläche analysiert. Im Vergleich zum gestörten Zustand zeigte das Barfußlaufen eine zeitlichen Verschiebung der zeitabhängigen Muskelaktivierungspatterns (Motor Primitives) und eine Reorganisation der zeitunabhängigen Koeffizienten (Motor Modules). Zusammenfassend, konserviert Fortbewegung über unebener Oberfläche, im Vergleich zu ebener, Motor Modules, während Motor Primitives im Allgemeinen breiter werden. Diese Ergebnisse unterstützen die Idee einer erhöhten Robustheit in der motorischen Kontrolle während der instabilen Fortbewegung. / The need to move over uneven, continuously changing terrains is part of our daily life. Thus, the central nervous system must integrate an augmented amount of information in order to be able to cope with the unpredictability of external disturbances. A consequence of this increased demand might be a flexible recombination of the modular organisation of movement creation and control. At the expense of motion’s accuracy, it is possible that the system responds by increasing its control’s robustness (i.e. ability to cope with errors). However, the strategies employed by the central nervous system to organise movement are still poorly understood. One possibility is that movements are constructed through a small amount of linearly combined patterns of activations, called muscle synergies. Amongst the several possibilities of perturbing locomotion, the removal of footwear and the use of uneven surfaces are two valid options. In a first step, I conducted a thorough analysis of the methodologies useful for a) the evaluation of spatiotemporal gait parameters using plantar pressure distribution data and b) the extraction of muscle synergies using non-negative matrix factorisation. Afterwards, I analysed the modular organisation of c) shod and barefoot running and d) walking and running over an even- and an uneven-surface treadmill. The modular organisation of locomotion, assessed through the extraction of muscle synergies, changed when perturbations were introduced. Compared to the shod condition, barefoot running underwent, mostly due to the different foot strike pattern, a reorganisation of the time-independent coefficients (motor modules) and a time-shift of the time-dependent muscle activation patterns (motor primitives). Uneven-surface locomotion, compared to even-surface, conserved motor modules, while motor primitives were generally wider, confirming the idea of an increased robustness in motor control during unsteady locomotion.
435

The organisation of the neuromuscular responses to the presence of perturbations during the execution of balance training exercises

Munoz-Martel, Victor 30 May 2024 (has links)
Stürze sind weltweit die zweithäufigste Ursache für Verletzungen und Todesfälle, und stellen eine massive Belastung für jedes Gesundheitssystem dar. Die meisten Stürze resultieren aus einer fehlgeschlagenen Reaktion auf unerwartete Störungen der Fortbewegung, wie z. B. Stolpern oder Ausrutschen. Unter den vielen bestehenden Interventionsmodellen, die auf das Risiko von Stürzen abzielen, sind bewegungsbasierte Interventionen die kosteneffektivsten. Da bei den meisten Trainingsansätzen die verbesserte Gleichgewichtsfähigkeit nur begrenzt auf untrainierte Situationen übertragen werden kann, müssen Faktoren, wie die Retention und die Dosis-Wirkungs-Beziehung noch ermittelt werden. Des Weiteren sind die Mechanismen, welche den wirksamen Trainingsmaßnahmen zugrunde liegen, noch nicht vollständig erforscht. Training der grundlegenden Mechanismen zur Wiederherstellung des Gleichgewichts (d. h. die Gegenrotation von Körpersegmenten und die Modulation der Unterstützungsfläche) unter instabilen Bedingungen, sowohl unter den trainierten Bedingungen als auch unter unbekannten Bedingungen, verbessert. Darüber hinaus erhöhte dieses Training die kraftgenerierende Kapazität der Muskeln der unteren Extremitäten, was die Ausführung von Gleichgewichtswiederherstellungsreaktionen weiter fördert. Auf der Grundlage dieser vielversprechenden Ergebnisse versucht diese Arbeit, Kenntnisse über die zugrundeliegenden neuromechanischen Anpassungen dieses vorteilhaften Trainingsansatzes, zu liefern. Robustheit kann als Folge verschiedener Modulationen von Muskelsynergien entstehen. Die Wahl der Strategie von Faktoren wie der Ausprägung der Störung, sowie der Ausprägung und Beschränkungen der Bewegungsaufgabe, und der wahrgenommenen Herausforderung für das Gleichgewicht bestimmt wird. Außerdem erhöht das Training auf instabilen Oberflächen nicht per se die mechanischen Anforderungen an die Beinmuskulatur. Die Zunahme der Muskelkraft scheint daher eine Folge neuronaler Anpassungen zu sein. / Falls are the second leading cause of unintentional injury and death worldwide. Among manifold causes, most fall result from a failed response to unexpected perturbations such as a trip or slip. Fall-related injuries can significantly impair quality of life, and their consequences represent a massive burden for any healthcare system. Amid fall prevention paradigms, exercise-based interventions are the most cost-effective. However, most training approaches have a limited transfer to untrained situations and the underlying mechanisms of effective training interventions are still not fully understood. Training the execution of the fundamental balance recovery mechanism (i.e., counterrotating body segments and increasing the base of support) in the presence of perturbations has been reported as an alternative capable of improving balance recovery performance in both trained and non-trained situations and of increasing the force capacity of the lower limb, further promoting the execution of balance recovery reactions. Based on these promising results, this thesis endeavours to provide insight into the fundamental elements promoting the neuromechanical adaptations underpinning the reported advantages of this training paradigm. The analysis of the neuromuscular responses to unstable surfaces during a training session revealed different strategies to cope with perturbations and increase robustness. These different modulations of muscle synergies depend on several factors such as the characteristics of the task and the individual capacities. Moreover, training on unstable surfaces did not increase the mechanical demands upon the leg muscles per-se. Thus the gains in muscle force observed after training the fundamental mechanism of balance recovery onto unstable surfaces are likely a consequence of neural adaptations.
436

Le rôle des symptômes d'hyperactivité- impulsivité dans la performance à une tâche de pointage manuel : quel rôle pour l'inattention?

Noué, Patrick 05 1900 (has links)
L'intégralité de ce projet a été réalisé à l'aide de logiciels sous licence libre. / Une évaluation du nombre de symptômes d'hyperactivité-impulsivité et d'inattention a été faite sur 277 jumeaux au moyen d'une entrevue semi-structurée administré aux parents, basée sur une échelle validée et communément admise, et une tâche de pointage a été demandée à chacun d'eux. La tâche de pointage a été effectuée avec chaque main successivement vers une cible dont la position à 135° ou à 45° était déterminée aléatoirement. Les tracés ont été classés en trois catégories selon le type de la première correction volontaire qu'ils présentaient sur leurs profils cinématiques : absence de correction, correction de position, correction dynamique. Ce projet veut caractériser la relation entre le taux de chaque type de correction et le nombre de symptômes de TDAH chez une population d'enfants ne répondant majoritairement pas à un diagnostic clinique de TDAH. Il a été montré que la présence de corrections de position était fréquemment corrélée à la présence de symptômes d'hyperactivité-impulsivité, mais pas, ou rarement, de symptômes d'inattention. D'autre part, il a été aussi remarqué que le taux de correction augmentait significativement lorsque le mouvement de pointage était effectué de la main gauche, sans égard à la dominance manuelle du sujet. Le premier résultat n'était pas attendu, étant donné la littérature relativement épaisse montrant un lien entre l'inattention et les problèmes de coordination motrice. Le second résultat, par contre, laisse entendre que la différenciation fonctionnelle hémisphérique d'un point de vue de contrôle attentionnel, ou de la motricité de la main gauche, serait affectée par le TDAH. / Symptoms linked to ADHD were assessed on 277 twins according to the commonly recognized dimensions formed by hyperactivity-impulsivity and inattention. A semi-structured interview administered to parents was used for the assessment. Subjects were asked to perform a pointing task. Left and right hands were tested in turn, and to reach a target placed either at 135° or 45°. Order of appearance was randomly determined. All traces were categorized according to the first voluntary correction as shown in their kinematic profiles : no correction, position correction, and dynamic correction. This project proposes to characterize the link between each correction type frequency and hyperactivity-impulsivity and inattention symptoms. The population studied was mostly subclinical and did not reach ADHD diagnosis criteria. Position corrections were shown to be correlated quite reliably to hyperactivity- impulsivity symptoms, but not to inattention symptoms. Deficits were most reliably linked with left hand use. The first result was unexpected considering abundant literature confirming the link between inattention and fine motor deficits, but the second one is more in line with a less exploited hypothesis stating that hemispherical functional differentiation related to control of the hand, or control of attention is affected by ADHD.
437

Components of reaching and grasping an object may emerge following a single minimization process

Yang, Fang January 2008 (has links)
Mémoire numérisé par la Division de la gestion de documents et des archives de l'Université de Montréal.
438

Contrôle cortico-spinal des mouvements volontaires du coude

Brohman, Tara 04 1900 (has links)
Il existe plusieurs théories du contrôle moteur, chacune présumant qu’une différente variable du mouvement est réglée par le cortex moteur. On trouve parmi elles la théorie du modèle interne qui a émis l’hypothèse que le cortex moteur programme la trajectoire du mouvement et l’activité électromyographique (EMG) d’une action motrice. Une autre, appelée l’hypothèse du point d’équilibre, suggère que le cortex moteur établisse et rétablisse des seuils spatiaux; les positions des segments du corps auxquelles les muscles et les réflexes commencent à s’activer. Selon ce dernier, les paramètres du mouvement sont dérivés sans pré-programmation, en fonction de la différence entre la position actuelle et la position seuil des segments du corps. Pour examiner de plus près ces deux théories, nous avons examiné l’effet d’un changement volontaire de l’angle du coude sur les influences cortico-spinales chez des sujets sains en employant la stimulation magnétique transcrânienne (TMS) par-dessus le site du cortex moteur projetant aux motoneurones des muscles du coude. L’état de cette aire du cerveau a été évalué à un angle de flexion du coude activement établi par les sujets, ainsi qu’à un angle d’extension, représentant un déplacement dans le plan horizontal de 100°. L’EMG de deux fléchisseurs du coude (le biceps et le muscle brachio-radial) et de deux extenseurs (les chefs médial et latéral du triceps) a été enregistrée. L’état d’excitabilité des motoneurones peut influer sur les amplitudes des potentiels évoqués moteurs (MEPs) élicitées par la TMS. Deux techniques ont été entreprises dans le but de réduire l’effet de cette variable. La première était une perturbation mécanique qui raccourcissait les muscles à l'étude, produisant ainsi une période de silence EMG. La TMS a été envoyée avec un retard après la perturbation qui entraînait la production du MEP pendant la période de silence. La deuxième technique avait également le but d’équilibrer l’EMG des muscles aux deux angles du coude. Des forces assistantes ont été appliquées au bras par un moteur externe afin de compenser les forces produites par les muscles lorsqu’ils étaient actifs comme agonistes d’un mouvement. Les résultats des deux séries étaient analogues. Un muscle était facilité quand il prenait le rôle d’agoniste d’un mouvement, de manière à ce que les MEPs observés dans le biceps fussent de plus grandes amplitudes quand le coude était à la position de flexion, et ceux obtenus des deux extenseurs étaient plus grands à l’angle d’extension. Les MEPs examinés dans le muscle brachio-radial n'étaient pas significativement différents aux deux emplacements de l’articulation. Ces résultats démontrent que les influences cortico-spinales et l’activité EMG peuvent être dissociées, ce qui permet de conclure que la voie cortico-spinale ne programme pas l’EMG à être générée par les muscles. Ils suggèrent aussi que le système cortico-spinal établit les seuils spatiaux d’activation des muscles lorsqu’un segment se déplace d’une position à une autre. Cette idée suggère que des déficiences dans le contrôle des seuils spatiaux soient à la base de certains troubles moteurs d’origines neurologiques tels que l’hypotonie et la spasticité. / According to a dominant theory, the motor cortex is directly involved in pre-programming motor outcome in terms of movement trajectories and electromyographic (EMG) patterns. In contrast, the equilibrium point theory suggests that the motor cortex sets and resets the spatial thresholds, i.e., the positions of body segments at which muscles and reflexes begin to act. Movement parameters thereby emerge without pre-programming, depending on the difference between the actual and the threshold position of the body segments. To choose between these two theories of motor control, we investigated corticospinal influences associated with voluntary changes in elbow joint angle in healthy individuals using transcranial magnetic stimulation (TMS) of the brain site projecting to motoneurons of the elbow muscles. In order to minimize the influence of motoneuronal excitability on the evaluation of corticospinal influences, motor evoked potentials (MEPs) elicited by TMS were obtained during the EMG silent period produced by a brief muscle shortening prior to the TMS pulse. MEPs were obtained at a flexion and an extension elbow angle actively established by subjects. MEPs were recorded from 2 elbow flexors (biceps and brachioradialis) and 2 extensors (medial and lateral heads of triceps). Flexor MEP amplitude was bigger at the elbow flexion position in the case of the biceps and extensor MEPs were bigger at the extension position in both extensors studied (reciprocal pattern). MEPs observed in the brachioradialis did not differ at the two elbow orientations. A similar difference in corticospinal influences at the two elbow positions was often preserved when the tonic activity of elbow muscles was equalized by compensating the passive muscle forces at the two positions with a torque motor. Thus, corticospinal influences and EMG activity were de-correlated and it can be concluded that the corticospinal system is not involved in pre-determining the magnitude of motor commands to muscles. Results suggest that the corticospinal system resets the spatial thresholds for muscle activation when segments move from one position to another. This implies that deficits in spatial threshold control may underlie different neurological motor problems (e.g., hypotonia and spasticity).
439

Posturální funkce a motorické dovednosti dětí s vadným držením těla / Postural fuction and motor control in children with poor posture

Pelánková, Zuzana January 2015 (has links)
This diploma thesis focuses on two conditions that typically occure in childhood - poor posture and developmental coordination disorder. The theoretical part summarizes recent information on these diseases focusing on their etiology, prevalence, prognosis, methods of assessment, diagnosis and treatment. The main aim of the practical part was to evaluate the motor control of treated children with poor posture in comparison with children from the general population. The research group (13 children, mean age 9.85 years) and control group (16 children, mean age 9.94 years) were assessed using Movement Assessment Battery for Children 2. We found no significant difference between motor skills of treated children with poor posture and motor skills of children representing the general population. We also analysed whether treated children with poor posture reported less physical activity compared with the general population. By gathering data from questionnaires (completed by parents of tested children), no statistically significant difference was found. The difference was neither detected in test of posture and postural functions, where we investigated how poor posture of treated children can influence the results of the test. Powered by TCPDF (www.tcpdf.org)
440

KA\'I yxo: uma plataforma robótica bioinspirada para aplicações em monitoramento ambiental. / KA\'I yxo: a bio-inspired robotic platform for environmental monitoring.

Bernardi, Reinaldo de 18 November 2014 (has links)
Este trabalho apresenta a concepção, o projeto, o desenvolvimento e a validação experimental de uma plataforma robótica bioinspirada o robô KA\'I yxo com a habilidade de escalar árvores para aplicação em monitoramento ambiental. Tal motivação surgiu da necessidade crescente do estudo e do entendimento de ocorrências naturais pelas consequências envolvidas, muitas vezes trágicas. O monitoramento ambiental em larga escala e a dificuldade de acesso e cobertura de áreas significativas são fatores que indicam a importância e a utilidade de robôs nessas tarefas. O robô KA\'I yxo possui como aplicação primeira uma solução para aquisição de dados de radiação solar, temperatura, umidade e altitude, de maneira que a mesma seja uma ferramenta útil para pesquisadores, aplicação esta identificada como relevante para a pesquisa na área ambiental após visitas ao Instituto Nacional de Pesquisas da Amazônia INPA. O desenvolvimento da plataforma robótica bioinspirada exposto nesta tese apresenta a sua evolução, desde a versão inicial do robô Kamanbaré (seis versões), até a versão atual da plataforma KAI yxo (terceira versão). Para esta última, são expostos em detalhes os modelos mecânico e matemático. No modelo mecânico, a importante questão da mobilidade é considerada. O modelo matemático construído compreende a cinemática direta, a cinemática inversa, a definição da andadura e a dinâmica do robô. O texto contém também uma apresentação detalhada das arquiteturas de controle, de software e de hardware. A utilização de Geradores Centrais de Padrões (CPGs) é justificada e discutida em detalhes. O ajuste dos parâmetros da CPG é realizado por meio de um processo de otimização baseado na técnica de Times Assíncronos (A-Teams). Resultados experimentais obtidos com a plataforma robótica são apresentados e discutidos. / This work presents the conception, design, development and experimental validation of a bioinspired robotics platform the robot KA\'I yxo with the ability to climb trees for use in environmental monitoring. Such motivation arose from the growing need of studying and understanding the consequences of natural occurrences involved, often tragic. Environmental monitoring in large scale and the difficulty of access and coverage areas are significant factors that indicate the importance and the usefulness of robots in these tasks. As a first application, the robot KA\'I yxo represents a solution for data acquisition from solar radiation, temperature, humidity and altitude, so that it may be a useful tool for researchers. This application was identified as relevant to environmental research after visits to the National Institute of Amazonian Research INPA. The development of the bio-inspired robotics platform exposed in this thesis presents its evolution starting from the initial version of the robot Kamanbaré (six versions) and ending with the current version of KA\'I yxo platform (third version). For the latter, the mechanical and mathematical models are exposed in details. In the mechanical model, the important issue of mobility is considered. The mathematical model constructed comprises the forward kinematics, the inverse kinematics, the definition of the gait and the dynamics of the robot. The text also contains a detailed presentation of the control, software and hardware architectures. The use of Central Pattern Generators (CPGs) is justified and discussed. The tuning of the CPG parameters is performed by an optimization process based on the Asynchronous Teams (ATeams) technique. Experimental results obtained with the robotic platform are presented and discussed.

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