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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.
101

Study of the earthquake source process and seismic hazards

Twardzik, Cedric January 2014 (has links)
To obtain the rupture history of the Parkfield, California, earthquake, we perform 12 kinematic inversions using elliptical sub-faults. The preferred model has a seismic moment of 1.21 x 10^18 Nm, distributed on two distinct ellipses. The average rupture speed is ~2.7 km/s. The good spatial agreement with previous large earthquakes and aftershocks in the region, suggests the presence of permanent asperities that break during large earthquakes. We investigate our inversion method with several tests. We demonstrate its capability to retrieve the rupture process. We show that the convergence of the inversion is controlled by the space-time location of the rupture front. Additional inversions show that our procedure is not highly influenced by high-frequency signal, while we observe high sensitivity to the waveforms duration. After considering kinematic inversion, we present a full dynamic inversion for the Parkfield earthquake using elliptical sub-faults. The best fitting model has a seismic moment of 1.18 x 10^18 Nm, distributed on one ellipse. The rupture speed is ~2.8 km/s. Inside the parameter-space, the models are distributed according the rupture speed and final seismic moment, defining a optimal region where models fit correctly the data. Furthermore, to make the preferred kinematic model both dynamically correct while fitting the data, we show it is necessary to connect the two ellipses. This is done by adopting a new approach that uses b-spline curves. Finally, we relocate earthquakes in the vicinity of the Darfield, New-Zealand earthquake. 40 years prior to the earthquake, where there is the possibility of earthquake migration towards its epicentral region. Once it triggers the 2010-2011 earthquake sequence, we observe earthquakes migrating inside regions of stress increase. We also observe a stress increase on a large seismic gap of the Alpine Fault, as well as on some portions of the Canterbury Plains that remain today seismically quiet.
102

Sprint analysis of athletes with intellectual impairments

Andrews, Barry 03 1900 (has links)
Thesis (M Sport Sc (Sport Science))--Stellenbosch University, 2008. / Intellectually impaired (II) athletes are not allowed to participate at the Paralympic Games because there is no accepted classification system for these athletes. The rationale for this study was to see if there are any physical differences existing in the sprint performance of II and non-II athletes and to see if there is a way to incorporate these differences into a new (accepted) classification system. The objective of this study was to identify any physical sources for the differences between II and non-II, with regard to the acceleration phase, the first 30m of the 60m sprint race, which could then be used in conjunction with other tests in the classification of II athletes. This new classification system might then allow II athletes to participate in the Paralympic Games again. 32 II athletes (22 male and 10 females) and 14 non-II athletes (10 males and 4 females) were used in this study. The sprint performance was analysed and compared of each athlete using the DartFish ProSuite software programme. The data collected from these analysis was then compared using the unpaired t-test, looking for any significant differences between the groups (p<0.05). From this analysis, it was concluded that stride length was the reason for the poorer performance of the II group when compared to the non-II group. Further research is required before definite conclusions can be made on the possible reasons for this difference.
103

Cheminė Galaktikos kinematinės žvaigždžių grupės sudėtis / Chemical composition of kinematically selected Galactic stellar group

Ženovienė, Renata 13 July 2010 (has links)
A. Helmi ir kt. (2006 m.) ieškojo praeityje vykusių akrecinių įvykių pėdsakų Paukščių Tako galaktikoje naudodami B. Nordström ir kt. (2004 m.) katalogą, kuriame yra pateikti tikslūs 13240 F, G, K spektrinės klasės nykštukių kinematiniai duomenys, temperatūra (Teff., K) ir metalingumas [Fe/H]. Pagal koreliaciją tarp apocentro (A), pericentro (P) ir kampinio judesio kiekio momento z kryptimi Lz, buvo identifikuotos trys kinematinės žvaigždžių grupės, kurios, manoma, yra įkritusių palydovinių galaktikų liekanos. Šio darbo tikslas buvo ištirti žvaigždžių, kurios priklauso trečiajai kinematinei grupei, pagrindinius fizikinius atmosferų parametrus ir cheminę sudėtį. Aukštos kokybės spektrai gauti Šiaurės šalių optiniu teleskopu naudojant didelės skiriamos gebos (R≈68000) spektrografą FIES. Iš 10 žvaigždžių spektrų nustačiau jų atmosferų pagrindinius fizikinius parametrus: efektinę temperatūrą Teff, laisvojo kritimo pagreičio logaritmą log g, mikroturbulencijos greitį vt ir alfa proceso, geležies piko ir s proceso elementų gausas. Spektrus normalizavau ir cheminių elementų sugerties linijų ekvivalentinius pločius išmatavau naudodama Helsinkio observatorijoje sukurtą programinį paketą 4A. Tolimesnę spektrų analizę atlikau diferencialiniu atmosferos modelių metodu, naudojant Upsalos Astronomijos Observatorijoje (Švedija) sukurtą programinį paketą EQWIDTH. Ši programa pagal pateiktus fizikinius parametrus apskaičiuoja teorinius linijų ekvivalentinius pločius ir nustato cheminių... [toliau žr. visą tekstą] / Helmi et al. (2006) have used a homogeneous data set of 13240 nearby F- and G-type stars from the Nordström et al. (2004) catalogue, containing accurate spatial and kinematic information as well as metallicity and age parameters to search for signatures of past accretion events in the Milky Way Galaxy. From correlation between orbital parameters: apocentre (A), pericentre (P) and z-angular momentum (Lz) so called APL space, they identified tree new coherent groups of stars, that might correspond to the remains of disrupted satellites. The aim of this research is to study chemical composition of one of this stellar group. Using high-resolution spectra (R≈68000) I have derived the chemical composition of 10 F-G-K spectral type stars. High resolution spectra of stars been obtained by the FIES spectrograph on the Nordic Optical Telescope. From these stellar spectra I determined the basics stellar atmosphere parameters: effective temperature Teff [K], surface gravities log g, microturbulent velocities vt [km/s], and abundances of iron, α and s-process elements. The continuum was defined and the equivalent widths of the line measured with the 4A software package. The spectra were analysed using a differential model atmosphere technique with EQWIDTH program package. Models of stellar atmospheres was computed using MARCS code (http://marcs.astro.uu.se). The effective temperature were taken from Nordström et al. (2004). All temperatures were checked so that equal abundance results... [to full text]
104

Symmetries in the kinematic dynamos and hydrodynamic instabilities of the ABC flows

Jones, Samuel Edward January 2013 (has links)
This thesis primarily concerns kinematic dynamo action by the 1:1:1 ABC flow, in the highly conducting limit of large magnetic Reynolds number Rm. The flow possesses 24 symmetries, with a symmetry group isomorphic to the group O24 of orientation-preserving transformations of a cube. These symmetries are exploited to break up the linear eigenvalue problem into five distinct symmetry classes, which we label I-V. The thesis discusses how to reduce the scale of the numerical problem to a subset of Fourier modes for a magnetic field in each class, which then may be solved independently to obtain distinct branches of eigenvalues and magnetic field eigenfunctions. Two numerical methods are employed: the first is to time step a magnetic field in a given symmetry class and obtain the growth rate and frequency by measuring the magnetic energy as a function of time. The second method involves a more direct determination of the eigenvalue using the eigenvalue solver ARPACK for sparse matrix systems, which employs an implicitly restarted Arnoldi method. The two methods are checked against each other, and compared for efficiency and reliability. Eigenvalue branches for each symmetry class are obtained for magnetic Reynolds numbers Rm up to 10^4 together with spectra and magnetic field visualisations. A sequence of branches emerges as Rm increases and the magnetic field structures in the different branches are discussed and compared. All symmetry classes are found to contain a dynamo, though dynamo effectiveness varies greatly between classes, suggesting that the symmetries play an important role in the field amplification mechanisms. A closely related problem, that of linear hydrodynamic stability, is also explored in the limit of large Reynolds number Re. As the same symmetry considerations apply, the five symmetry classes of the linear instability can be resolved independently, reducing the size of the problem and allowing exploration of the effects of the symmetries on instability growth rate. Results and visualisations are obtained for all five classes for Re up to 10^3, with comparisons drawn between the structures seen in each class and with those found in the analogous magnetic problem. For increasing Re, multiple mode crossings are observed within each class, with remarkably similar growth rates seen in all classes at Re=10^3, highlighting a lack of dependence on the symmetries of the instability, in contrast with the magnetic problem. This thesis also investigates the problem of large-scale magnetic fields in the 1:1:1 ABC flow through the introduction of Bloch waves that modify the periodicity of the magnetic field relative to the flow. Results are found for a field with increased periodicity in a single direction for Rm up to 10^3; it is established that the optimal scale for dynamo action varies as Rm increases, settling on a consistent scale for large Rm. The emerging field structures are studied and linked with those of the original dynamo problem. On contrasting this method with a previous study in which the flow is instead rescaled, it is shown that the use of Bloch waves drastically increases the range of possible scales, whilst cutting required computing time. Through a multiple-scale analysis, the contribution from the alpha-effect is calculated for the 1:1:1 ABC flow and is seen in growth rates for Rm &lt;&lt; 1.
105

A Kinematic Comparison Between Greater-and Lesser-Skilled Powerlifters Doing the Traditional Style Deadlift

Canales, Daniel 12 1900 (has links)
Comparison kinematic models of the traditional style deadlift are presented. Data was obtained through film and analyzed via computer and computer graphics. The comparison between the models revealed that the greater-skilled: 1. used less trunk flexion from the instant of initial trunk lean to the instant of maximum trunk lean, 2. used less knee extension (in same time interval as 1), and 3. demonstrated a smaller horizontal distance between the body center of mass (CM) and the CM of the bar at the instant the bar left the platform. A trend was also observed in which the greater-skilled subjects demonstrated less thoracic lean than the lesser-skilled group at the time the bar reached knee level.
106

Změny stereotypu chůze vlivem stárnutí / The age related changes in walk stereotype

Vojtová, Michaela January 2011 (has links)
1 Abstract: The aim of this study quantify and compare the differences in the dynamics of foot movement compared with static in adulthood and old age, focusing on the midstance phase. A secondary objective is to outline the relationship with the angular distribution of pressure on the sole. For measurements two measuring methods were used. The kinematic analysis named Qualysis was used as a main method and system of plantar pressure insoles Pedar X as a complementary method. The difference in measured distance of 1-MP calcaneus, 5MP - calcaneus and pronate angle of calcaneus was prooved using the statistical calculation, which confirmed the hypothesis of half clear a significant degree. Subsequently, the changes were further specified using the results of the distribution of maximum force and contact time of the soles.
107

Hodnocení změn kvality chůze tanečníků v porovnání s běžnou populací. / The evaluating of the change of walking quality in dancers in comparison with the normal population

Korošová, Kateřina January 2014 (has links)
Thesis name: The evaluating of the change of walking quality in dancers in comparison with the normal population Thesis goal: This thesis deals with effect of long-term ballet dance on kinematic parameters of gait. The theoretical part includes basic characteristics of gait cycle and kinesiological and biomechanical findings of ballet movement and its compensatory mechanisms in musculoskeletal system. There is analyzed angular parameters of gait cycle in ballet dancers in performance of walking in the experimental part. The results will show if the many-years intensive training of dance affects the alignment of particular joints of the body during human walk. Method: Kinematic analysis by Qualisys system allowing automatic processing of record obtained with infrared cameras. Qualisys uses its own high-frequency cameras for precise movement tracking of the measured object using active or passive markers. Gathered data from device were processed and statictically evaluated with Microsoft Office Excel. Keywords: gait, bipedal locomotion, dance, gait analysis, gait of dancers, ballet, kinematics analysis
108

Kinematická analýza chůze u pacientů s koxartrózou / Kinematic analysis of gait in patients with hip osteoarthrosis

Říhová, Barbora January 2015 (has links)
Author: Barbora Říhová Title: Kinematic Analysis of Gait in Patients with Hip Osteoarthrosis Objectives: The aim of this thesis was to analyse the gait patterns in probands with Stage III osteoarthritis of the hip joint, to compare these patterns with published norms and to confirm a set of pre-established hypotheses. Method: The thesis was designed as a case study, the purpose of which was to observe changes in the pelvis and trunk extension during gait, associated with significant degenerative changes in the hip joint. A total of 9 probands with Stage III osteoarthritis of the hip joint (6 females, 3 males) took part in the study. A complete physiotherapy assessment was carried out as part of the study. The temporal gait parameters were used to measure the probands' walking speed and relative stance phase duration. The following variables were measured in the frontal plane: lateral displacement of the pelvis and trunk toward the stance limb (cm) and pelvic obliquity toward the swing limb (degrees). A 3D motion analysis and evaluation of kinematic parameters were carried out using the Qualisys motion capture system device consisting of 6 infrared cameras. Gait was measured at different walking speeds during a 10-second time frame and the data was subsequently subtracted from a minimum of 5 gait...
109

Experimentální vyšetření parametrů chůze člověka / Experimental investigation of human gait analysis parameters

Hrušková, Natália January 2014 (has links)
Title: Experimental investigation of human gait analysis parameters Objective: The main objective of diploma thesis was an experiment, that examined kinematic and dimensional parameters of human gait which was captured by several cameras and acquired data was recorded in 2D and 3D measurement. Secondary objective was to compare and statistically evaluate data acquired from measurement. The objective of analysis was to discover and describe possible regularities, patterns of human gait and other connections in investigated subjects. Methods: Comparative method was used in the thesis. The purpose of the experiment was to compare parameters measured during attempts of every subject that were conducted under different conditions (different velocity, dressed, undressed, in the environment of 2D and 3D recording) and also to compare different subjects with each other. Results: In the experiment we observed that it is possible to prove the relation between the length of a step and the velocity of gait and also the relation between the change in the body height and the velocity of human gait by three dimensional recording of gait and its analysis. This contention was confirmed in the comparison dressed and undressed subjects. The result of the experiment was, that with increasing velocity of gait is...
110

Evaluation tridimensionnelle du complexe scapulo-huméral et du rachis cervical : méthodologie d'évaluation et applications cliniques / 3D assessment of the shoulder and the cervical spine : assessment methodologies and clinical applications

Roren, Alexandra 29 October 2012 (has links)
Le but de ce travail est d’améliorer les techniques de mesure cinématique tridimensionnelle (3D) afin d’étudier les schémas cinématiques du complexe de l’épaule et du rachis cervical chez des sujets sains et pathologiques. La première partie de ce travail propose un rappel d’anatomie fonctionnelle, une revue de la littérature de la cinématique du complexe scapulo-huméral et une mise au point sur les techniques de mesure de ces deux complexes articulaires. La deuxième partie de ce travail a pour objectif d’évaluer à partir d’études cliniques originales : - la reproductibilité des techniques de mesure des rotations des complexes scapulo-huméral et cervical et d’en proposer une amélioration par une analyse simultanée des translations du barycentre de la scapula ainsi que par la mesure couplée des deux complexes articulaire. - les schémas cinématiques de la scapula dans différents modèles de pathologies ostéo-articulaires au cours de gestes analytiques et fonctionnels. En conclusion, ce travail de thèse met en évidence : une variabilité intra-individuelle dans la capacité à reproduire un mouvement à l’identique avec le membre supérieur et à conserver la même précision dans le repositionnement de la tête. - des mouvements de translation 3D de la scapula, dont certains de grande amplitude, associés aux rotations des mouvements de faible amplitude du rachis cervical associés aux mouvements du membre supérieur en faveur de son rôle proprioceptif. - des schémas cinématiques scapulaires spécifiques : - de la lésion neurologique en cas de scapula alata dynamique. - de la nature fonctionnelle de la tâche en cas de pathologies ostéo-articulaires communes / The aim of this work was to improve the methods of kinematic assessment of the shoulder complex and of the cervical spine in order to improve understanding of scapular and cervical spine kinematics in asymptomatic and symptomatic subjects. The first part of this work provides a reminder of functional anatomy, a literature review of the 3D kinematics of the shoulder complex and issues relating to measurement techniques of both articular complexes. The second part is based on original clinical studies assessing: - the reliability of the measurement techniques of the rotations of both articular complexes and their enhancement by addition of scapular translations and the coupled mobility of the cervical spine and shoulder complexes. - the patterns of scapular kinematic in different ostéo-articular pathologies In conclusion, this work highlights: - intra-individual variability in the ability to reproduce a movement with the upper arm and in the accuracy of repositioning the head . -3D scapular translations (some with large ranges) associated with scapular rotations. - small movements of the cervical spine associated with upper limb movements relating to the proprioceptive role of the cervical. - spine specific scapular kinematic patterns depending on: - neurological lesions in the case of dynamic scapula alata, - the type of movement in common osteo articular pathologies

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