• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 91
  • 19
  • 17
  • 17
  • 8
  • 8
  • 5
  • 4
  • 4
  • 4
  • 2
  • 1
  • 1
  • 1
  • Tagged with
  • 211
  • 41
  • 24
  • 22
  • 20
  • 19
  • 19
  • 17
  • 16
  • 15
  • 15
  • 14
  • 13
  • 13
  • 13
  • 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.
161

Vliv aplikovaných pohybových programů na pohybový systém osob po amputaci dolní končetiny / The Effect of Adapted Exercise Programs on Musculoskeletal System of Lower Limb Amputees

Sobotková, Ivona January 2020 (has links)
The subject of this dissertation was the creation of the adapted exercise program for unilateral transfemoral amputees and its verification in practice. The content of this program was chosen based on the practical experience and theoretical background in the field of anatomy, kinesiology, rehabilitation, lower- limb amputations and Motion Capture technologies. The four-month intervention program was designed as an adapted corrective exercise aimed at the major muscle groups influencing the posture, especially the position of the pelvic segment, which is the dominant element in the kinematic chain. The aim of this project was to ascertain whether this intervention can affect the pelvic tilt (in frontal and sagittal plane) of unilateral transfemoral amputees and so improve their quality of life. This was a project based on combination of quantitative and qualitative research methods. The measurement of the size of angles determining the pelvic tilt by Qualisys optoelectronic system was the essence of the quantitative part of the research. Qualitative data were collected through semi-structured in-depth interviews from persons who completed whole project. This research is by its nature and focus characterized as a set of case reports and as a pilot study, proof of concept respectively. 10 unilateral...
162

A Graph Attention plus Reinforcement Learning Method for Antenna Tilt Optimization

Ma, Tengfei January 2021 (has links)
Remote Electrical Tilt optimization is an effective method to obtain the optimal Key Performance Indicators (KPIs) by remotely controlling the base station antenna’s vertical tilt. To improve the KPIs aims to improve antennas’ cooperation effect since KPIs measure the quality of cooperation between the antenna to be optimized and its neighbor antennas. Reinforcement Learning (RL) is an appropriate method to learn an antenna tilt control policy since the agent in RL can generate the optimal epsilon greedy tilt optimization policy by observing the environment and learning from the state- action pairs. However, existing models only produced tilt modification strategies by interpreting the to- be- optimized antenna’s features, which cannot fully characterize the mobile cellular network formed by the to- be- optimized antenna and its neighbors. Therefore, incorporating the features of the neighboring antennas into the model is an important measure to improve the optimization strategy. This work will introduce the Graph Attention Network to model the neighborhood antenna’s impact on the antenna to be optimized through the attention mechanism. Furthermore, it will generate a low- dimensional embedding vector with more expressive power to represent the to- be- optimized antenna’s state in the RL framework through dealing with graph- structural data. This new model, namely Graph Attention Q- Network (GAQ), is a model based on DQN and aims to acquire a higher performance than the Deep Q- Network (DQN) model, which is the baseline, evaluated by the same metric — KPI Improvement. Since GAQ has a richer perception of the environment than the vanilla DQN model, it thereby outperforms the DQN model, obtaining fourteen percent performance improvement compared to the baseline. Besides, GAQ also performs 14 per cent better than DQN in terms of convergence efficiency. / Optimering av fjärrlutning är en effektiv metod för att nå optimala nyckeltal genom fjärrstyrning av den vertikala lutningen av en antenn i en basstation. Att förbättra nyckeltalen innebär att förbättra sammarbetseffekten mellan antenner eftersom nyckeltalen är mått på kvalitén av sammarbetet mellan den antenn som optimeras och dess angränsande antenner. Förstärkande Inlärning (FI) är en lämplig metod för att lära sig en optimal strategi för reglering av antennlutningen eftersom agenten inom FI kan generera den optimala epsilongiriga optimeringsstrategin genom att observera miljön och lära sig från par av tillstånd och aktioner. Nuvarande modeller genererar dock endast lutningsstrategier genom att tolka egenskaperna hos den antenn som ska optimeras, vilket inte är tillräckligt för att karatärisera mobilnätverket bestående av antennen som ska optimeras samt dess angränsande antenner. Därav är inkluderingen av de angränsande antennernas egenskaper i modellen viktig för att förbättra optimeringsstrategin. Detta arbete introducerar Graf- Uppmärksammat Nätverk för att modellera de angränsande antennernas påverkan på den antenn som ska optimeras genom uppmärksamhetsmekanismen. Metoden genererar en lågdimensionell vektor med större förmåga att representera den optimerade antennens tillstånd i FI modellen genom att hantera data i struktur av en graf. Den nya modellen, Graf- Uppmärksammat Q- Nätverk (GUQ), är en modell baserad på DQN med mål att nå bättre prestanda än en standard DQN- modell, utvärderat efter samma mätvärde –– förbättring av nyckeltalen. Eftersom GUQ har en större upfattning av miljön så överträffar metoden DQN- modellen genom en fjorton procent bättre prestandaökning. Dessutom, så överträffar GUQ även DQN i form av snabbare konvergens.
163

Etude du mécanisme de la sensation du flux ciliaire dans l'organiseur droite gauche du poisson zèbre / Zebrafish left-right organizer : multi-scale analysis of cilia behaviors and flow-sensing mechanism for symmetry-breaking

Rua Ferreira, Rita 31 March 2017 (has links)
Les cils motiles et statiques jouent d’importants rôles dans la détermination de l’axe gauche-droite (GD) qui, en général, est mis en place par l’intermédiaire de flux directionnels générés dans des structures spécialisées appelées organisateurs gauche-droite (OGD). C’est ce point clé du développement qui dictera une organogenèse asymétrique. Dans mon projet de thèse, nous avons développé une méthode, appelée 3D-Cilia Map, et analysé l’organisation tridimensionnelle de l’implantation des cils afin d’extraire les paramètres clés responsables de la mise en place du flux directionnel et par conséquent de l’asymétrie GD. En résumé, nos résultats suggèrent qu’un mécanisme de signalisation chimique serait le plus plausible pour induire la rupture de la symétrie GD. Plus tard, les cellules réguleront intrinsèquement l’orientation asymétrique des cils à leur surface. Le travail présenté ici contribue de façon importante à nos connaissances actuelles concernant le comportement des cils et les mécanismes de sensation des flux dans l’établissement de l’axe gauche droite au sein de l’organisateur gauche-droite du poisson zèbre. / Both motile and immotile cilia play important roles in left-right (LR) axis determination, which generally involves cilia-mediated directional flows in organized structures (LR organizers, LRO) in which the LR symmetry is broken, thus driving asymmetric organogenesis in the developing embryos. In my PhD project we aimed to developed a method (3D-Cilia Map) and analyze the three-dimensional organization of ciliary implantation in order to extract the key parameters modulating the directional flow involved in breaking the axis of symmetry in the zebra fish LRO. Altogether, our results suggest the initial mechanism to break the LR symmetry is most likely to be based on the transport of achemical signal, while later, cells intrinsically provide their cilia the cues to orient asymmetrically. The work presented here represents an important contribution to our current understanding of cilia behaviors and flow-sensing mechanisms in the establishment of the left-right axis in the zebra fish LRO.
164

Hardening Distortions of Serial Produced Gears

Olofsson, Anders January 2017 (has links)
Hardening distortions are unwanted changes in shape and dimension that arise during hardening of steel components. Uncontrolled distortions induce random errors to the manufacturing process, and have a strong negative impact on manufacturing costs. The distortions are not only caused by the hardening process, several factors from previous manufacturing steps including the component geometry itself contribute to varying extent. The aim of the current work is to investigate the main influencing factors on hardening distortions for serial produced gears. The investigations were done on two different types of gears for heavy-duty transmissions, crown wheels for the rear axle central gear and main shaft gears for the gearbox. The steel was produced using either continuous casting or ingot casting. For rectangular continuously cast steel, the effect of disabling magnetic stirring of the steel melt during casting was investigated, finding a strong reduction of gear runout for crown wheels. Segregations in crown wheels produced from the top and bottom of ingots were shown to go in opposite directions, producing opposite back-face tilts. For crown wheels quenched one at a time, influences of stacking level on the hardening tray were found, indicating an impact from small variations in the carburizing process, despite identical quenching conditions. For main shaft gears, horizontal loading gave considerably less roundness and runout errors but increased flatness errors compared to vertical loading. This thesis shows the complexity of the distortion phenomenon and how several factors interact and contribute to the final result. It is shown that factors with significant impact on hardening distortions for one component may be less important for another component. With this in mind, each type of component to be hardened should be produced by a manufacturing chain where each process step is carefully chosen with respect to minimizing distortions. / <p>QC 20170516</p>
165

Vliv změny postavení hlavy a krční páteře na percepci subjektivní zrakové vertikály / The effect of changes in the position of the head and cervical spine on the perception of the subjective visual vertical

Pálek, David January 2021 (has links)
lateroflexion of 20 ř, after remaining 5 minutes in lateroflexion The mean deviation of the healthy population was measured at 1.26 ř ± 0.901. There ř ± 1.48) and subsequently a further increase in deviations when staying in this position (3.45 ř ± 3.15). The direction of SVV movement showed a more or less symmetrical distribution to the vestibular systém, head tilt, head
166

Fano Resonances in Time-Dependent Wells

Gregefalk, Anton January 2023 (has links)
Floquet’s theorem, a temporal analogue of Bloch’s theorem, is used for studying a time-dependent potential. With applications in cold atoms on optical lattices, quantum dots and more, there is a growing interest in Floquet engineering exotic materials and phases. By solving the time-dependent Schrödinger equation scattering amplitudes are derived from which the transmission spectrum are generated. The driving field induces Floquet sidebands into which the particle can inelastically scatter. Fano resonances are observed when the incoming particle and a bound state of the staticpotential differ by some energy quanta. This process is mediated by the driving field. The scattering matrix and transmission spectra are reproduced from previous work on electron gas, graphene, and a semi-metal admitting a point of quadratic band touching (QBT). The QBT system is extended with linear tilting along the potential, which proves to be another good quantum number for tunable control.
167

A Comparison of Keyboard and Tilt Interaction Techniques for Racing Video Game

Zhu, Ziyi January 2022 (has links)
In gaming, the market is increasingly emphasizing "natural" interaction techniques, introducing a wide range of external devices. The high price of many external devices reduced its popularity. However, smartphone as another widely available product, I wanted to use sensors of the smartphone to simulate "natural" interaction techniques and explore the changes and influence it had on players as opposed to traditional keyboard input in order to understand its value as an intermediary between traditional input methods and unique external devices. In this study, I developed a racing game that uses the button and tilt input via the phone to simulate a steering wheel. Also, I studied the participants’ gaming data and experiences during the experiment. My experiments found that the tilt input outperformed the keyboard input, especially for participants with less than five years of gaming experience. Furthermore, the tilt input gave players an immersive and varied gaming experience. I offered four hypotheses to explain my findings and suggested that game designers refer to them. / På spelmarknaden betonas i allt högre grad "naturliga" interaktionstekniker, vilket innebär att ett brett utbud av externa enheter introduceras. Det höga priset på många externa enheter har minskat deras popularitet. Jag ville dock använda smartphones som en annan allmänt tillgänglig produkt, och jag ville använda smartphonesensorer för att simulera "naturliga" interaktionstekniker och utforska vilka förändringar och vilket inflytande de hade på spelarna jämfört med traditionell tangentbordsinmatning, för att förstå dess värde som en mellanhand mellan traditionella inmatningsmetoder och unika externa anordningar. I den här studien utvecklade jag ett racingspel som använder knapp- och lutningsinmatning via telefonen för att simulera en ratt. Dessutom studerade jag deltagarnas speldata och upplevelser under experimentet. Mina experiment visade att tilt-inmatningen överträffade tangentbordsinmatningen, särskilt för deltagare med mindre än fem års spelvana. Dessutom gav lutningsinmatningen spelarna en uppslukande och varierad spelupplevelse. Jag erbjöd fyra hypoteser för att förklara mina resultat och föreslog att speldesigners ska hänvisa till dem.
168

Explainable Reinforcement Learning for Remote Electrical Tilt Optimization

Mirzaian, Artin January 2022 (has links)
Controlling antennas’ vertical tilt through Remote Electrical Tilt (RET) is an effective method to optimize network performance. Reinforcement Learning (RL) algorithms such as Deep Reinforcement Learning (DRL) have been shown to be successful for RET optimization. One issue with DRL is that DRL models have a black box nature where it is difficult to ’explain’ the decisions made in a human-understandable way. Explanations of a model’s decisions are beneficial for a user not only to understand but also to intervene and modify the RL model. In this work, a state-ofthe-art Explainable Reinforcement Learning (XRL) method is evaluated on the RET optimization problem. More specifically, the chosen XRL method is the Embedded Self-Prediction (ESP) model proposed by Lin, Lam, and Fern [16] which can generate contrastive explanations in terms of why an action is preferred over the other. The ESP model was evaluated on two different RET optimization scenarios. The first scenario is formulated as a single agent RL problem in a ’simple’ environment whereas the second scenario is formulated as a multi agent RL problem with a more complex environment. In both scenarios, the results show little to no difference in performance compared to a baseline Deep Q-Network (DQN) algorithm. Finally, the explanations of the model were validated by comparing them to action outcomes. The conclusions of this work is that the ESP model offers explanations of its behaviour with no performance decrease compared to a baseline DQN and the generated explanations offer value in debugging and understanding the given problem. / Att styra antenners vertikala lutning genom RET är en effektiv metod för att optimera nätverksprestanda. RL-algoritmer som DRL har visat sig vara framgångsrika för REToptimering. Ett problem med DRL är att DRL-modeller är som en svart låda där det är svårt att ’förklara’ de beslut som fattas på ett sätt som är begripligt för människor. Förklaringar av en modells beslut är fördelaktiga för en användare inte bara för att förstå utan också för att ingripa och modifiera RL-modellen. I detta arbete utvärderas en toppmodern XRL-metod på RET-optimeringsproblemet. Mer specifikt är den valda XRL-metoden ESP-modellen som föreslagits av Lin, Lam och Fern [16] som kan generera kontrastiva förklaringar i termer av varför en handling föredras framför den andra. ESP-modellen utvärderades på två olika RET-optimeringsscenarier. Det första scenariot är formulerat som ett problem med en enstaka agent i en ’enkel’ miljö medan det andra scenariot är formulerat som ett problem med flera agenter i en mer komplex miljö. I båda scenarierna visar resultaten liten eller ingen skillnad i prestanda jämfört med en DQN-algoritm. Slutligen validerades modellens förklaringar genom att jämföra dem med handlingsresultat. Slutsatserna av detta arbete är att ESPmodellen erbjuder förklaringar av dess beteende utan prestandaminskning jämfört med en DQN och de genererade förklaringarna ger värde för att felsöka och förstå det givna problemet.
169

Metallogeny of a Volcanogenic Gold Deposit, Cape St. John Group, Tilt Cove, Newfoundland

Hurley, Tracy 04 1900 (has links)
<p> The "B" horizon at Tilt Cove occurs in subaqueous mafic volcanics near the base of the Silurian Cape St. John Group. It is 3 metres below a well-banded oxide iron formation ("A" horizon). </p> <p> Mineralization in the "B" horizon is analogous to that of the East Mine in that it is volcanogenic and has resulted in extensive chloritization of the footwall rocks, and in the deposition of banded sulphides or the replacement of the existing mafic volcanics by sulphides. There are differences in the geochemistry mineral textures and mineral types. The East Mine host volcanics are alkali depleted basaltic komatiites to magnesium theleiites. The horizon host volcanics are spillitized magnesium tholeiites. Samples of ore from the East Mine show well-developed colloform and framboidal textures. Pyrite, magnetite, hematite and chalcopyrite are the dominant minerals with minor sphalerite and accessory covellite. Samples from the horizon show relict colloform textures and framboids with less internal structure due to overgrowths. Atoll textures indicating extensive replacement are common. Pyrite is the dominant sulphide followed by sphalerite, chalcopyrite, accessory covellite and gold. The chalcopyrite occurs both as replacement of pyrite and exsolution in sphalerite. The most significant difference between samples from the East Mine and "B" horizon is the greater abundance of gold in the "B" horizon and its correlation with sphalerite. </p> / Thesis / Bachelor of Science (BSc)
170

Evaluierung der Einsatzfähigkeit einer neuartigen Lotstocktechnologie

Eder, Rafael 01 December 2022 (has links)
Diese Diplomarbeit behandelt die neuartige Lotstocktechnologie AP20 der Firma Leica Geosystems AG. Es geht um die Evaluierung dieses Produkts und die Fragestellung, inwiefern sich die Arbeitsweise und Produktivität in der Vermessungspraxis verändert. So erfolgt zuerst eine Literaturrecherche und Zusammenstellung des aktuellen Stands der Technik. Anschließend werden die Daten und Fakten des AP20 genannt und die Methodik zur Überprüfung erläutert. Die Evaluierung dieser Technologie erfolgt anhand eines fiktiven Kundenauftrages, welcher klassische Vermessungsaufgaben widerspiegelt. Ob die Erfüllung dieses Auftrages gelingt und wie sich die benötigte Zeit für diese Vermessungsaufgaben mit Hilfe des AP20 verändert wird im Zuge dieser Arbeit beantwortet. / This thesis deals with the novel AP20 pole technology from Leica Geosystems AG. It is about the evaluation of this product and the question of how the working method and productivity in surveying practice are changing. The first step is a literature search and a compilation of the current state of the art. Then the data and facts of the AP20 are mentioned and the methodology for the review is explained. This technology is evaluated on the basis of a fictitious customer order, which reflects classic surveying tasks. Whether the fulfillment of this order is successful and how the time required for these surveying tasks changes with the help of the AP20 will be answered in the course of this work.

Page generated in 0.0398 seconds