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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.
1081

Procedurální animace lidské chůze / Procedural Animation of Human Walk

Mohelník, Petr January 2016 (has links)
Animation of human walk is employed in many interactive applications, mostly in computer games. There are many ways to create such animation which differ in compromise among naturalness, control over animation and computing time. This work implements procedural animation which is applicable for walking on uneven terrain. Skeletal animation is used for manipulation with model of human body. Furthermore, inverse kinematics is described and implemented. That allows for adaptation to uneven terrain. It also describes phases of human walk, so we can accurately aproximate them. Proposed solution enables specification of walk using number of parameters and is able to adapt to surrounding terrain. The result should be usable in creation of computer games and should allow for creation of specific animation of human walk without need to create such animation manually.
1082

Vliv použité běžecké obuvi na kinematiku dolních končetin a pánve v průběhu oporové fáze běhu / The influence of running shoes on leg and pelvis kinematics during the stance phase of run

Novák, Čestmír January 2014 (has links)
Title: The influence of running shoes on leg and pelvis kinematics during the stance phase of run Objectives: The main objective of this thesis is to detect whether there exists a connection between the type of shoes used and changes in pelvis and legs kinematics in sagittal plane while running. Methology: For a purpose of the thesis research 12 active sportsmen (6 men and 6 women) participated in lab tests. Each of them was running on a tread mill for three time sequences - each counting 20 seconds - with changes in conditions applied as follows: barefoot run, minimalistic shod run, classic shod run. The 3D analysis was analysed using the Qualisys system (200 Hz). Data analytics was executed using the Qualisys Track Manager programme, where a comparative method was applied. Further statistical procedures ANOVA a Tukey test were performed in a programme called OriginPro 8. Key findings: The executed lab tests proved influence of running shoes on legs and pelvis kinematics during a stance phase of run. The main changes in kinematics were found in an ancle during touchdown, where the angle significantly increased while running barefoot rather than classic shod running. An analysis of pelvis kinematics parameters has proven that there are no changes in pelvis movements while running in different types...
1083

Ein Werkzeug zur schnellen Konfiguration biomechanischer Simulationen in der Produktentwicklung

Krüger, Daniel, Wartzack, Sandro January 2012 (has links)
Aus Punkt 1: "Neben der Funktionserfüllung und den Kosten ist der wirtschaftliche Erfolg eines Produktes nicht zuletzt dadurch gegeben, wie gut es den Wünschen, Bedürfnissen und Fähigkeiten seiner Nutzer entspricht. Zwischen Nutzer und Produkt existieren vielfältige Wechselwirkungen, die erfasst und verstanden werden müssen, um Produktkonzepte hinsichtlich der oben genannten Kriterien bewerten und optimieren zu können. Die Philosophie der menschzentrierten Produktentwicklung (MZP) besteht folglich darin, in allen Phasen der Produktentwicklung konsequent das Gesamtsystem bestehend aus Nutzer, Produkt und Umwelt zu betrachten."
1084

Galaxie se slupkami: kinematika slupek, rozpad satelitní galaxie a dynamické tření / Shell galaxies: kinematical signature of shells, satellite galaxy disruption and dynamical friction

Ebrová, Ivana January 2013 (has links)
Title: Shell galaxies: kinematical signature of shells, satellite galaxy disruption and dynamical friction Author: Ivana Ebrová Department / Institute: Astronomical Institute of the Academy of Sciences of the Czech Republic Supervisor of the doctoral thesis: RNDr. Bruno Jungwiert, Ph.D., Astronomical Institute of the Academy of Sciences of the Czech Republic Abstract: Stellar shells observed in many giant elliptical and lenticular as well as a few spiral and dwarf galaxies presumably result from radial minor mergers of galaxies. We show that the line-of-sight velocity distribution of the shells has a quadruple-peaked shape. We found simple analytical expressions that connect the positions of the four peaks of the line profile with the mass distribution of the galaxy, namely, the circular velocity at the given shell radius and the propagation velocity of the shell. The analytical expressions were applied to a test-particle simulation of a radial minor merger, and the potential of the simulated host galaxy was successfully recovered. Shell kinematics can thus become an independent tool to determine the content and distribution of dark matter in shell galaxies up to ~100 kpc from the center of the host galaxy. Moreover we investigate the dynamical friction and gradual disruption of the cannibalized galaxy...
1085

The role of goal representations in action control

Walter, Andrea Michaela 07 November 2013 (has links)
Actions are goal-directed. It can be the goal of an action to change the environment (i.e. to produce an effect), but also to change one´s own situation in the environment (i.e. to move to a physical target). Previous research has shown that kinematics of actions directed towards physical targets are not only mere reactions to such targets. Instead, targets evoke intentional goals. Representations of such intentional goals influence action execution. However, thus far, most studies in the context of the ideomotor theory of action control have focused on the influence of anticipated action effects on action planning. The role of targets as action goals as well as the role of goal anticipations on overt action execution has mostly been neglected. In this dissertation the role of goal representations in action control was investigated. The ideomotor theory served as a theoretical framework. It was assumed that targets function as action goals similar to action effects and that action goals influence action execution by the anticipation of upcoming events. Action execution towards targets and towards effects was compared. This was done in the temporal and the spatial domain. Furthermore, goal representations were manipulated in order to evaluate their influence on action execution and to disentangle the role of physical target characteristics and the role of goal representations. The findings obtained strengthen the assumption that goal representations play an important role in action control. First, both targets and effects can be viewed as goals of an action in the temporal and spatial domain. Second, movement kinematics are shaped by the way targets are represented as action goals, rather than by physically target properties. In conclusion, as goal representations are formed before the action is actually executed they influence action execution by the anticipation of upcoming events. The ideomotor theory of action control should incorporate action targets as goals similar to action effects.
1086

Models of the Morphology, Kinematics, and Star Formation History of the Prototypical Collisional Starburst System NGC 7714/7715 = ARP 284

Struck, Curtis, Smith, Beverly J. 20 May 2003 (has links)
We present new N-body, hydrodynamical simulations of the interaction between the starburst galaxy NGC 7714 and its poststarburst companion NGC 7715, focusing on the formation of the collisional features, including (1) the gas-rich star-forming bridge, (2) the large gaseous loop (and stellar tails) to the west of the system, (3) the very extended H I tail to the west and north of NGC 7714, and (4) the partial stellar ring in NGC 7714. Our simulations confirm the results of earlier work that an off-center inclined collision between two disk galaxies is almost certainly responsible for the peculiar morphologies of this system. However, we have explored a wider set of initial galaxy and collisional encounter parameters than previously and have found a relatively narrow range of parameters that reproduce all the major morphologies of this system. The simulations suggest specific mechanisms for the development of several unusual structures. We find that the complex gas bridge has up to four distinct components, with gas contributed from two sides of NGC 7715, as well as from NGC 7714. The observed gas-star offset in this bridge is accounted for in the simulations by the dissipative evolution of the gas. The models suggest that the most recently formed gas bridge component from NGC 7715 is interacting with gas from an older component. This interaction may have stimulated the band of star formation on the north side of the bridge. The models also indicate that the low surface brightness H I tail to the far west of NGC 7714 is the end of the NGC 7715 countertail, curved behind the two galaxies. The sensitivity of the tidal structures to collision parameters is demonstrated by comparisons between models with slightly different parameter values. Comparison of model and observational (H I) kinematics provides an important check that the morphological matches are not merely fortuitous. Line-of-sight velocity and dispersion fields from the model are found to match those of the observations reasonably well at current resolutions. Spectral evolutionary models of the NGC 7714 core by Lançon et al. suggest the possibility of multiple starbursts in the last 300 Myr. Our hydrodynamic models suggest that bursts could be triggered by induced ringlike waves and a postcollision buildup of gas in the core of the galaxy.
1087

Etudes à haute résolution angulaire de la cinématique des enveloppes proto-stellaires / High angular resolution studies of the kinematics of proto-stellar envelopes

Gaudel, Mathilde 27 November 2018 (has links)
Les étoiles se forment par effondrement gravitationnel de condensations pré-stellaires. Le jeune embryon stellaire (phase Classe 0) croît en masse par l'accrétion progressive de l'enveloppe de gaz et de poussières dans lequel il est enfoui. Par conservation du moment cinétique, si le moment du coeur pré-stellaire est totalement transféré à l'embryon pendant la phase d'accrétion, la force gravitationnelle ne peut contrer la force centrifuge et l'embryon se fragmente prématurément. Pour former une étoile comme notre Soleil, l'enveloppe en rotation doit nécessairement réduire son moment cinétique de 5 à 10 ordres de grandeur en l'évacuant ou en le redistribuant. L'un des principaux défis de la formation stellaire est de quantifier l'ampleur de ce "problème du moment cinétique" et d'identifier les mécanismes responsables de la redistribution du moment.L'objectif de cette thèse est d'étudier la cinématique des enveloppes proto-stellaires de Classe 0 afin d'établir leurs distributions de moment cinétique. Pour cela, j'ai utilisé des observations de raies moléculaires à haute résolution angulaire de l'Interféromètre du Plateau de Bure et du télescope de 30m de l'IRAM issues du large programme CALYPSO (Continuum and Lines in Young Protostellar Objects, PI : Ph. André) pour un échantillon de 12 proto-étoiles de Classe 0 à une distance d<400 pc. Cette analyse a permis de mesurer des mouvements de rotation différentielle et d'établir, pour la première fois, des distributions radiales du moment cinétique spécifique sur une grande gamme d'échelles (~50-10000 au) dans 11 des 12 enveloppes proto-stellaires de l'échantillon. Deux régimes distincts ont ainsi été mis en exergue: un profil constant à petites échelles (<1600 au) et une augmentation du moment avec le rayon aux grandes échelles (1600-10000 au).Le profil constant montre que la matière participant directement à la formation de l'étoile possède un moment cinétique spécifique (~5 10^-4 km/s pc, <1600 au) similaire à celui observé dans les petits disques entourant les étoiles T-Tauri.Les gradients de vitesse observés aux grandes échelles (>3000 au), historiquement utilisés pour mesurer la rotation des coeurs et quantifier le problème du moment cinétique, ne sont pas dus à la pure rotation des enveloppe proto-stellaires, mais sont dominés par d'autres mécanismes. Plusieurs scénarios sont donc discutés pour interpréter le changement de régime dans les profils de moment cinétique aux échelles >1600 au: une empreinte des conditions initiales de la phase pré-stellaire, un changement de mécanismes dominants (contre-rotation, transition effondrement-rotation) ou l'influence de la dynamique des filaments interstellaires (turbulence, effondrement, chocs) dans lesquels les proto-étoiles sont enfouies. / Stars form via the gravitational collapse of a pre-stellar condensation. The young stellar embryo (Class 0 phase) mass increases via the progressive accretion of the gaseous and dusty envelope within which it is buried. As a direct consequence of the angular momentum conservation, if the angular momentum of the pre-stellar core is totally transferred to the central embryo during the accretion phase, the gravitational force can not counteract the centrifugal force and the embryo fragments prematurely before reaching the main sequence. To form a star such as our Sun, the rotating envelope needs to reduce its angular momentum by 5 to 10 orders of magnitude by ejecting or redistributing it. One of the main challenges of stellar formation is to quantify the amplitude of this "angular momentum problem" and identify the mechanisms responsible for the angular momentum redistribution.The goal of this PhD thesis is to study the kinematics of Class 0 protostellar envelopes in order to probe the distribution of their angular momentum. To do this, I used high-resolution observations of molecular lines with the Plateau de Bure Interferometer and the 30m telescope at IRAM taken as part of the large programme CALYPSO (Continuum and Lines in Young Protostellar Objects, PI : Ph. André). The sample gathers 12 Class 0 protostars with distances d<400 pc. This analysis allows to measure differential rotation motions and provides, for the first time in a large sample, robust constraints on the radial distributions of specific angular momentum in a large range of scales (~50-10000 au) for 11 of the 12 protostellar envelopes targeted in the sample. Two distinct regimes are revealed: a constant profile at small scales (<1600 au) and an increasing of the angular momentum at larger radii (1600-10000 au).The constant profile shows that the specific angular momentum (~5 10-4 km/s pc, <1600 au) of the material directly involved in the star formation is similar to the value observed in the small disks surrounding the T-Tauri stars.Velocity gradients observed on large scales (>3000 au) - that are historically used to measure the rotation of the core and quantify the angular momentum problem - are not due to pure envelope rotation but can be dominated by other mechanisms. I discuss several scenarios in order to interpret this change of regime in the angular momentum profiles at scales >1600 au: the imprints of the initial conditions of the pre-stellar phase, a change of dominant mechanisms (counter-rotation, transition between infall and rotation) or the influence of the interstellar filament dynamics (turbulence, collapse, shocks) within which protostars are buried.
1088

Biomechanical differences between elite able-bodied kayakers and elite para-kayakers during paddling : The second and third step of creating the new Paralympic classification system / Biomekaniska skillnader mellan elit kanotister utan funktionsnedsättning och elit para-kanotister vid paddling : Det andra och tredje steget av utvecklingen av det nya Paralympiska klassificeringssystemet för Parakanot

Rosén, Johanna January 2015 (has links)
Aim The aim of the study was to examine the differences between able-bodied athletes (AB) and three para-athlete (PA) classes in three-dimensional range of motion (RoM) for the major joints of the body, and to define which joint angles are correlated with power output during paddling on a kayak ergometer. An additional aim was to validate three new classification tests used in classification of Paracanoe athletes. This study was an integral part of developing a new evidence-based classification system for Paracanoe which was accepted by the International Paralympic Committee in 2015. Method 41 PA (13 F and 28 M; 35 ± 9.0 years, 70.6 ± 12.5 kg, 1.74 ± 0.12 m) and 10 AB (4 F and 6 M; 22 ± 3.5 years, 78.3 ± 10.2 kg, 1.79 ± 0.06 m) participated in the study. Three-dimensional kinematic data was recorded using an optoelectronic system containing 12 infrared cameras capturing reflective markers placed on the participants, the paddle and on the force transducers. Force was measured at the paddle to enable calculations of power output. The kinematic and kinetic data were collected during paddling on the kayak ergometer at incremental intensities starting at a low intensity level (50 W). The athletes then increased intensity with 50 W up to a high intensity level which was defined as the highest level the athlete could maintain with good technique for 20 stroke cycles. The athletes were then asked to paddle at a maximal level. The kinematic and kinetic data were imported into Visual 3D and MATLAB where all calculations were made. Results There were significant differences between the AB and the three PA classes for joint angles in the shoulder (e.g. flexion/extension and internal/external rotation, AB&gt;PA), trunk (trunk rotation and trunk flexion, AB&gt;PA) and leg (hip, knee and ankle flexion AB&gt;PA) during paddling. Significant positive correlations were seen for both men and women between power output and trunk rotation RoM, hip, knee and ankle flexion RoM and in maximal trunk flexion during paddling. A positive correlation was also seen between the newly developed classification tests and the RoM values and power output. Conclusion This study showed that the RoM of the trunk and legs are positively correlated with power output during paddling on a kayak ergometer and that there is a significant difference between the AB and the PA classes in trunk and leg RoM. The results also showed that the newly developed classification tests are valid tests to use in classification of Paracanoe athletes. / Syfte och frågeställningar Syftet med studien var att undersöka skillnaderna mellan icke funktionsnedsatta idrottare (AB) och tre klasser av funktionsnedsatta idrottare (PA) i tredimensionellt rörelseomfång (RoM) i samtliga större leder i kroppen, och att definiera vilka leder som korrelerade med power output vid paddling på kajak ergometer. Ett ytterligare syfte var att validera tre nya klassificeringstester för klassificering i Parakanot. Denna studie var en viktig del vid utvecklingen av ett nytt evidensbaserat klassificeringssystem för Parakanot vilket blev accepterat av Internationella Paralympiska Kommitteen under 2015. Metod 41 PA (13 K och 28 M; 35 ± 9.0 år, 70.6 ± 12.5 kg, 1.74 ± 0.12 m) och 10 AB (4 K och 6 M; 22 ± 3.5 år, 78.3 ± 10.2 kg, 1.79 ± 0.06 m) deltog i studien. Tredimensionell kinematisk data samlades in med ett optoelektroniskt system innehållandes 12 infraröda kameror som registrerade reflekterande markörer som var fäst på försökspersonerna, på paddeln och på kraftgivarna. Kraft mättes vid paddeln vilket möjliggjorde beräkning av power output. Den kinematiska och kinetiska datan samlades in vid paddling på kajak ergometer på olika intensitetsnivåer och idrottarna startade på en låg intensitetsnivå (50 W). Idrottarna ökade sedan intensitet med 50 W upp till en hög intensitet vilket definierades som den högsta nivån som idrottarna kunde paddla stabilt på med bra teknik i 20 drag cykler. Idrottarna paddlade sedan på en maximal nivå. Den kinematiska och kinetiska datan importerades sedan till Visual3D och MATLAB där alla beräkningar utfördes. Resultat Det fanns en signifikanta skillnader mellan AB och de tre PA klasserna för ledvinklarna i skuldran (flexion/extension och inåt/utåt rotation, AB&gt;PA), bålen (bål rotation och bål flexion, AB&gt;PA) och i benen (höft, knä och ankel flexion, AB&gt;PA) vid paddling. Det fanns en signifikant positiv korrelation för både män och kvinnor mellan power output och RoM i bål rotation, höft, knä och ankel flexion och i maximal bål flexion vid paddling. En positiv korrelation fanns även mellan de nyutvecklade klassificeringstesterna och RoM värdena samt power output. Slutsats Studien visade att bål- och benrörelsen är positivt korrelerat med power output vid paddling på kajak ergometer och att det är en signifikant skillnad mellan AB och PA klasserna i bål och ben RoM. Resultaten visade också att de nyutvecklade klassificeringstesterna är valida tester för användning inom klassificering av Parakanotister. / <p>Kursen Projektarbete.</p>
1089

Digitalisering av skogsskötsel med GNSS : Kostnadseffektiv kartläggning med Arduino &amp;Real-Time Kinematic / Digitalization of forestry with GNSS : Cheaper surverying with Arduino &amp; Real Time Kinematic

Lyrå, Martin January 2019 (has links)
Det finns en efterfrågan på hög-precisa GNSS-enheter i skogshantering som utförs av skogsinspektörer, skogsägare, och plantskolor. Problemet är att en genomsnittlig enhet kostar 30 000 SEK och uppåt. Därför söker man efter en billigare lösning med samma noggrannhet. Lösningen bör vara tillgänglig och lätt då det är önskvärt att monterasystemet på ett planteringsrör eller stav. Lösningen bestod av Arduino och U-Blox:s NEO-M8P-2 monterat på kretskort från SparkFun. Kommunikation mellan enheterna realiserades meden NTRIP-program som tredje part. Med Bluetooth för NTRIP-klienten och LTE (mobiltelefoni) för NTRIP-servern kommunicerade en rover och en basstation med nätet, för att överföra hämta och skicka korrigeringsdata från stationen till rovern. Lösningen lyckades med att uppnå grundligt resultat och några förväntningar. Man lyckades med att ta fram en lösning som kostar mindre än 6000 SEK, eller 2500 SEK om man väljer bort basstationen och endast behållermottagaren; rovern. Alla målen och förväntningar för resultat kunde inte uppfyllas på grund av problem och utmaningar i både lösningen och komplikationer orsakade avfaktorer utanför projektets ram.
1090

Výpočtové modelování dynamických projevů v kontaktu kola a kolejnice s obecnou geometrií kontaktních povrchů / Numerical Simulations of Dynamic Loads in Wheel-Rail Contact with Shape Irregularities

Jandora, Radek January 2012 (has links)
During life of railway vehicles, shape irregularities develop on wheels and rails because of wear. The shape irregularities then affect forces in wheel-rail contact and cause further damage of contact surfaces, vibrations and noise and increase risk of derailment. A numerical simulation of railway vehicle motion with more details on contact surfaces geometry was created to investigate dynamic contact loads in wheel-rail contact. A variety of methods can be used to evaluate forces in rolling contact, the method chosen for this study was algorithm CONTACT based on boundary element method. Four studies are presented in this papers: contact loads from a wheel with a flat and with a wavy tread pattern, loads on wavy rail and load in a curve. The first three studies investigated effects of existing wear patterns, the last one looked for cause of common wear pattern developing on rails. Results of the studies with worn components used showed that the worst kind of shape irregularities is a flat present on wheel. This type of shape cause loss of contact and following impacts. The study of ride in curve showed that cause of high wear in curves, especially those with small radii, is caused by vibration of wheelset. This vibration is then caused by different length of inner and outer rail and wheels travelling along a different path.

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