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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.
241

Modelling and Analysis of a Screw Joint Test Rig

Fallsberg, Beatrice January 2017 (has links)
Today, tightening tools are widely used in the industry and on the market you will find several products that have been assembled with the help of tightening tools. For example, tightening tools are used in the automotive industry and when assembling computer hardware. It is important that the tightening tools are robust and of high quality in order to fulfil the demanded requirements. High assembly speed has entailed an extensive use of tightening tools. To ensure that the tightening tools have the desired properties, tightening tools are tested continuously using so-called test systems. This puts high demands on the test systems since it is of importance that the tightening tools can be tested in a simple, fast and reliable way as well as repeatedly. Therefore, Atlas Copco would like to investigate whether a test system constructed with an electrical motor is a good choice. The idea of this thesis is to investigate possibilities and limitations in a test system consisting of an electrical motor that emulates the behaviour of a screw joint. To be able to investigate hardware limitations a test rig is constructed and then modelled in MATLAB. Further, simulations have been carried out in order to analyse the possibilities and limitations of such a test rig. The conclusion is that the implemented LQ controller seems to be able to control the braking motor sufficiently like a screw joint.
242

Contrôle corticospinal sur les circuits neuronaux spinaux au cours de la locomotion chez l'homme / Corticospinal control on spinal neuronal circuits during locomotion in humans

Jabbour, Berthe 25 September 2014 (has links)
Cette thèse étudie la modulation des circuits neuronaux spinaux impliqués dans les fonctions motrices et leur contrôle corticospinal lors de la locomotion chez l’Homme sain et après accident vasculaire cérébral (AVC). Dans ce contexte, la stratégie utilisée a consisté à moduler les comportements de ces circuits en modifiant soit les volées afférentes d’origine suprasegmentaire ou les volées afférentes d’origine périphérique et d’étudier le retentissement de ces modifications sur le comportement des circuits neuronaux spinaux au cours de différentes tâches motrices dont la marche.Trois grands thèmes émergent de ce projet :« L’influence combinée des entrées corticospinales et de l’inhibition réciproque sur l’activité des motoneurones des fléchisseurs plantaires de la cheville » a été étudiée en station debout et lors de la marche stabilisée. Les résultats ont suggéré que l'interaction entre les motoneurones spinaux, les interneurones inhibiteurs Ia et les volées motrices corticospinales descendantes ainsi que leur contribution relative à l'activité des motoneurones des fléchisseurs plantaires de la cheville dépendent de la tâche motrice. Plus d’interaction entre les entrées descendantes et les interneurones Ia pendant la station debout était présente, probablement pour renforcer l’activation tonique des motoneurones du soléaire.« La modulation liée à la tâche de l’inhibition spinale croisée entre les membres inférieurs chez l’Homme » a été étudiée au niveau des muscles soléaires en position assise, debout et lors de la marche stabilisée. Nos résultats suggèrent que la transmission neurale croisée, via les interneurones commissuraux des groupes I et II, est déprimée par les entrées descendantes bilatérales du cortex moteur ou pendant le mouvement volontaire. La modulation spécifique de l’inhibition croisée du groupe II au cours de la locomotion suggère un contrôle des structures mésencéphaliques monoaminergiques et son rôle dans la coordination des jambes pendant la locomotion. « L’influence de la musique sur les automatismes locomoteurs après un Accident Vasculaire Cérébral » a été étudiée durant la marche stabilisée chez les patients atteints d’AVC. Nos résultats préliminaires suggèrent que l’écoute musicale modulerait les réseaux neuronaux médullaires impliqués dans les automatismes locomoteurs. / This thesis investigates the modulation of spinal neuronal circuits involved in motor function and their corticospinal control during locomotion in healthy humans and after stroke. In this context, the strategy was to modulate the behavior of these circuits by modifying either the afferent volleys from suprasegmental origin or from peripheral origin and to study the impact of these changes on the behavior of spinal neuronal circuits during different motor tasks such as walking.Three major themes emerge from this project:« Combined influence of corticospinal inputs and reciprocal inhibition on ankle plantar flexor motoneuron activity during walking » was investigated during standing and during stabilized walking. The results suggested that the interaction between spinal motoneurons, Ia inhibitory interneurones and motor corticospinal descending volleys and their relative contribution to the activity of plantar flexor motoneurons of the ankle depend on the motor task. More interaction between descending inputs and Ia interneurones during standing was present, presumably to strengthen the tonic activation of the soleus motoneurons.« Task-related modulation of crossed spinal inhibition between human lower limbs» has been studied at the soleus muscles in sitting, standing and during stabilized walking. Our results suggest that crossed neural transmission via commissural interneurones of groups I and II, is depressed by bilateral descending inputs of motor cortex during voluntary movement. Specific modulation of the crossed inhibition by group II afferents during locomotion suggests a control from monoaminergic mesencephalic structures and its role in legs coordination during locomotion.« The influence of music on locomotor automatisms after stroke» was investigated during stabilized locomotion in stroke patients. Our preliminary results suggest that music modulate the spinal neuronal networks involved in locomotor automatisms.
243

Temporal pattern in the muscles of the upper limbs and the trunk in the archery / Padrão temporal nos músculos dos membros superiores e do tronco no tiro com arco

Nadjila Tejo Machado 15 March 2018 (has links)
Central nervous system stabilizes body in disturbance by means of anticipatory and compensatory postural adjustments to maintain stable position. Disturbance effects in joint are reduced by activation of agonist and antagonist forearm muscles, the muscles allow consistency by steady posture during shot. Studies showed the importance of posture in the shot, but without focus on the anticipatory and compensatory postural adjustments. The objective of this study was to analyze an electrical activity of archers during the shot an arrow with the bow. Participants consisted of 10 archers of the Brazilian National Team of archery. Electromyography captured electrical activity in 12 muscles. Accelerometer in handle indicated the beginning of the movement. Temporal pattern separated in 500 milliseconds pre and post clicker fall. Protocol started by Maximal Voluntary Isometric Contraction of 12 muscles. Archers release 3 blocks of 6-arrows in warm-up. Archers throw arrows for 12 blocks with 6-arrows with interval of 20 minutes after the block 6. One-way Analysis of Variance and Tukey Test compared temporal pattern. One-way Analysis of Variance with repeated measures compared temporal pattern and 6-arrows. Results showed that all muscles (except m. Lumbar Multifidus) increase in their demand with the proximity of the arrow release. The muscles decreased their activity due to reduced demand in compensatory and modulation phase. Comparison between 12 blocks of 6-arrows showed 3 ways of temporal pattern: 1) muscles affected by phases and muscles affected by all/any phases in the blocks of 6-arrows, 2) muscles affected by phases and muscles unaffected by all/any phases in the blocks of 6-arrows and 3) muscles unaffected by phases and muscles affected by all phases in the blocks of 6-arrows. Muscles were not affected by phases/blocks maintain muscle activity along intervals by similar muscular demand. Cross-correlation between motor muscles showed that forearm muscles obtained inverse relationship between them. Other motor muscles were strong correlation between them. Postural muscles m. Lumbar Multifidus, m. Latissimus Dorsi, m. Upper Trapezius were strong correlation with all postural muscles. Motor and postural muscles showed that m. Triceps Brachii, m. Pectoralis Major Clavicular Head and m. Posterior Deltoid showed strong correlation with all postural muscles. In conclusion, muscle activity increases in anticipatory phase and muscle activity decrease after clicker fall. There are 3 ways to compare phases and blocks: affected by phases and 1) muscles affected/2) muscles unaffected by all/any phases in the blocks of 6-arrows and 3) muscles unaffected by phases and affected by all phase in the blocks of 6-arrows. Correlation in motor muscles showed that forearm muscles obtained inverse relationship between them. Postural muscles m. Lumbar Multifidus, m. Latissimus Dorsi, m. Upper Trapezius were strong correlation with all postural muscles. Motor and postural muscles showed that m. Triceps Brachii, m. Pectoralis Major Clavicular Head and m. Posterior Deltoid showed strong correlation with all postural muscles / O sistema nervoso central estabiliza o corpo na perturbação por meio de ajustes posturais antecipatórios e compensatórios para manter a postura estável. Os efeitos da perturbação na articulação são reduzidos pela ativação dos músculos agonistas e antagonistas do antebraço, os músculos permitem a consistência no tiro pela postura estável. Os estudos mostram a importância da postura no tiro, mas não se concentrarem nos ajustes posturais antecipatórios e compensatórios. O objetivo desse estudo foi analisar a atividade elétrica muscular de arqueiros durante o atirar uma flecha com o arco. Os participantes foram 10 arqueiros da Seleção Brasileira de Tiro com Arco. A eletromiografia captou a atividade elétrica muscular de 12 músculos. O acelerômetro no punho indicou o início do movimento. As fases temporais foram separadas entre 500 milissegundos pré e pós queda do clicker. O protocolo iniciou pela Contração Isométrica Voluntária Máxima dos músculos. Arqueiros lançaram 3 séries de 6 flechas no aquecimento. Arqueiros lançaram 12 séries de 6 flechas com intervalo de 20 minutos após a série 6. Análise de Variância One-way e o Tukey compararam as fases temporais. Análise de Variância One-way com medida repetidas comparou as fases temporais e os blocos de 6 flechas. Os resultados mostraram que todos os músculos (exceção do m. Multifido Lombar) aumentaram a demanda com a proximidade de soltura da flecha. Os músculos diminuem sua atividade pela redução da sua demanda na fase compensatória e de modulação. A comparação entre blocos de 6 flechas mostrou 3 formas do padrão temporal: 1) músculos afetados pelas fases e músculos afetado por todos/alguns fases nos blocos de 6 flechas, 2) músculos afetados pelas fases e músculos não afetados por todos/alguns fases nos blocos de 6 flechas e 3) músculos não afetados pelas fases e músculos afetados por todas as fases nos blocos de 6 flechas. Os músculos não afetados fases pelas fases/blocos mantem a atividade elétrica muscular ao longo dos intervalos pela sustentação da demanda muscular. Correlação cruzada entre os músculos motores mostrou que os músculos do antebraço obtiveram relação inversa entre eles. Outros músculos motores apresentaram alta correlação entre eles. Músculos posturais m. Multifido Lombar, m. Latíssimo do Dorso, m. Trapézio Superior apresentaram alta correlação com todos os músculos posturais. Músculos motores e posturais mostraram que m. Tríceps Braquial, m. Peitoral Maior Clavicular e m. Deltoide Posterior teve alta correlação com todos os músculos posturais. Em conclusão, a atividade elétrica muscular aumenta a demanda na fase antecipatória e diminui na após queda do clicker. Existem 3 caminhos na comparação das fases e os blocos de 6 flechas: afetado pela fase e 1) músculo afetado/2) músculo não afetado por todos/algumas fases nos blocos, 3) músculo não afetado pelas fases e afetado por todos as fases nos blocos. A correlação cruzada entre os músculos motores mostrou que os músculos do antebraço obteram relação inversa entre eles. Músculos posturais m. Multifido Lombar, m. Latissimo do Dorso, m. Trapézio Superior foram altamente correlacionados com todos músculos posturais. Músculos posturais e motores mostraram que m. Triceps Brachial, m. Petoral Maior Clavicular e m. Deltoide Posterior mostraram alta correlação com todos os músculos posturais
244

Neurocorrelates of speech-motor planning and execution in adults and children who stutter

Brown, Bryan T. 01 December 2015 (has links)
There is a rich literature demonstrating that adults who stutter (AWS) demonstrate atypical functional brain activity during speech production. These differences can be characterized by increased activity in the right inferior frontal gyrus and premotor regions and decreased activity in the left inferior frontal gyrus, premotor area, and bilaterally in the superior temporal gyrus. The process of speech production requires motor movements first be planned and then executed. However, few studies have examined activity related to speech-motor planning independently from speech-motor execution. Additionally, due to methodological limitations, few investigations have examined functional brain activity in children who stutter (CWS). We hypothesized that AWS and CWS would demonstrate atypical brain activity related to both speech-motor planning and execution. Using Near Infrared Spectroscopy (fNIRS), we measured the change in oxygenated hemoglobin concentration (HbO) during speech-motor planning (repetition of nonwords with three repeated or different syllables) and speech-motor execution (covert/overt naming). Results indicated that both AWS and CWS demonstrated cortical activity that was atypical during speech-motor planning processes in the right inferior frontal gyrus and atypical speech-motor execution processes in the left inferior frontal gyrus. Deactivations in the left inferior frontal gyrus may reflect inefficient feedforward mechanisms for speech production. Inefficient feedforward mechanisms will likely result in more variable movements, for which larger feedback correction signals will be necessary. Overactivations in the right inferior frontal gyrus may reflect this increased correction. Additionally, AWS demonstrated atypical speech-motor planning activity in the right middle frontal gyrus, potentially related to the production of prosody. These results are presented within a theoretical framework of two competing theories of stuttering.
245

Muscle and kinematic coordination system in human walking / ヒト歩行における筋および運動学的協調構造の解明

Kibushi, Benio 25 March 2019 (has links)
京都大学 / 0048 / 新制・課程博士 / 博士(人間・環境学) / 甲第21861号 / 人博第890号 / 新制||人||213(附属図書館) / 2018||人博||890(吉田南総合図書館) / 京都大学大学院人間・環境学研究科共生人間学専攻 / (主査)教授 神﨑 素樹, 教授 石原 昭彦, 教授 久代 恵介 / 学位規則第4条第1項該当 / Doctor of Human and Environmental Studies / Kyoto University / DGAM
246

Application of Biological Control Principle in Understanding of Human Behavior Modulations / 生物制御原理に基づくヒトの行動調整メカニズムの理解に関する研究

Matti, Sakari Itkonen 23 September 2020 (has links)
京都大学 / 0048 / 新制・課程博士 / 博士(情報学) / 甲第22801号 / 情博第731号 / 新制||情||125(附属図書館) / 京都大学大学院情報学研究科知能情報学専攻 / (主査)教授 熊田 孝恒, 教授 西田 眞也, 教授 中村 裕一 / 学位規則第4条第1項該当 / Doctor of Informatics / Kyoto University / DFAM
247

The Effects of Reward and Risk Level Associated with Speeded Actions: Evidence from Behavior and Electroencephalography

Chen, Xingjie 25 October 2018 (has links)
Choosing a course of action in our daily lives requires an accurate assessment of the associated risks as well as the potential rewards. The present two studies investigated the mechanism of how reward and risk level influence the motor decisions of speeded actions (Chapter 2) and its neural dynamics (Chapter 3) by focusing on the beta band (15-30 Hz) oscillation patterns reflected in the EEG signals. Participants performed a modified version of the Go-NoGo task, in which they earned reward points based on the speed and accuracy of response. On each trial, the reward points at stake (120 vs. 6) and the probability that a Go signal would follow (Go-probability) were presented prior to a Go/NoGo signal (Trial Information Period). The behavioral results (from both Chapters 2 and 3) showed that larger amount of rewards can motivate people to respond faster, and this effect was modulated by the assessed risk, suggesting that decisions for actions are based on a systematic trade-off between rewards and risks. The EEG data showed that motor beta oscillations from the two studied brain regions reflected different levels of motivation towards a motor response across different reward and risk levels. Specifically, the lower beta power associated with higher reward and lower risk level. Collectively, the results provide a mechanistic understanding of how motivational cues are translated into action outcomes via modulating patterns of brain oscillations.
248

Vzdušný hokej - realizace a návrh automatického hráče / Air Hockey - construction design and control design of artificial player

Jašek, Dominik January 2020 (has links)
This diploma thesis deals with the design and implementation of an automatic Air hockey player. In particular, a gaming table and a kinematic type of H-bot robot and electronics are designed. The movement of the robot is ensured by two stepper motors, which are controled by the Arduino Micro using timer interrupts. The thesis is improved by additional elements, such as goal detection using photoelectric sensors and automatic firing of the puck from the goal and others. The Air hockey robot was practically realized in cooperation with Ondřej Sláma.
249

Optical Brain Imaging of Motor Cortex to Decode Movement Direction using Cross-Correlation Analysis

Lebel, Cynthia 12 1900 (has links)
The goal of this study is to determine the intentional movement direction based on the neural signals recorded from the motor cortex using optical brain imaging techniques. Towards this goal, we developed a cross-correlation analysis technique to determine the movement direction from the hemodynamic signals recorded from the motor cortex. Healthy human subjects were asked to perform a two-dimensional hand movement in two orthogonal directions while the hemodynamic signals were recorded from the motor cortex simultaneously with the movements. The movement directions were correlated with the hemodynamic signals to establish the cross-correlation patterns of firings among these neurons. Based on the specific cross-correlation patterns with respect to the different movement directions, we can distinguish the different intentional movement directions between front-back and right-left movements. This is based on the hypothesis that different movement directions can be determined by different cooperative firings among various groups of neurons. By identifying the different correlation patterns of brain activities with each group of neurons for each movement, we can decode the specific movement direction based on the hemodynamic signals. By developing such a computational method to decode movement direction, it can be used to control the direction of a wheelchair for paralyzed patients based on the changes in hemodynamic signals recorded using non-invasive optical imaging techniques.
250

Variability of Practice and Strength Training Periodization: When Theories Collide

Streder, Katherine Lauren 01 December 2013 (has links)
The primary purpose of this study was to examine whether variability of practice enhances neuromuscular adaptations when compared to traditional strength training. The secondary purpose was to investigate whether there was a difference in perception of exertion between the two strength programs. Forty one subjects (23 women and 18 men) were assigned to either the control group or one of two treatment groups by a blocked-random method. Subject's one repetition maximum (1RM) for the kettlebell press and leg press were measured at baseline, after 4 weeks of training, and after 8 weeks of training. The treatment groups completed 8 weeks of training consisting of 3 days a week with at least one recovery day in between each session. In weeks 1 through 3, subjects undergoing the traditional treatment completed 3 sets of 8 repetitions at 70% of their 1RM for each exercise. Weeks 4 through 6 were composed of 3 sets of 6 repetitions at 77% 1RM. In weeks 7 and 8, 3 sets of 4 repetitions at 85% 1RM were performed. Over the course of the eight weeks, the variable treatment was comprised of 5 sets of the kettlebell and leg press. A set of 4 repetitions at 77% of the subject's 1RM, one of 5 repetitions at 70% 1RM, another of 3 repetitions at 85% 1RM, one of 6 repetitions at 65% 1RM, and finally a set of 2 repetitions at 93% 1RM were performed every session. The order of these sets were changed every 3 weeks, altering where in the session the highest intensity set was in relation to the lower intensity sets. Ratings of perceived exertion (RPE) were recorded following treatment to determine subject's perception of intensity during each set. Analysis of variance with repeated measures did not reveal significantly different strength gains between treatment groups in either lift, although variable treatment resulted in greater mean strength gains over almost every time interval. Analyses of RPE data revealed significantly lower reported RPE values for the variable treatment compared to the traditional treatment in both lifts. The greater mean strength gains and significantly lower RPEs of the variable treatment program compel us to conclude it is a superior training method for increasing strength compared to the traditional program.

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