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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.
1

On interface modeling  with emphasis on friction

Söderberg, Anders January 2006 (has links)
The general trend toward increased use of computer models and simulations during product development has led to a need for accurate and reliable product models. The function of many products relies on contact interfaces between interacting components. To simulate the behavior of such products, accurate models of both components and interfaces are required. Depending on the purpose of the simulation, interface models of different degrees of complexity are needed. In simulation of very large systems with many interfaces, it might be computationally expensive to integrate detailed models of each individual interface. Condensed models, or abstractions, that describe the interface properties with a minimum of degrees of freedom are therefore required. This thesis deals with mechanical interfaces with an emphasis on friction. In the four appended papers friction models are discussed in terms of condensed models, as well as in terms of more detailed contact models. The aim is to study how friction can be modeled in behavioral simulation of products and to discuss the convenience and relevance of using different types of friction models as building blocks of a system model in behavioral simulations. Paper A presents a review of existing condensed friction models for sliding contacts under different running conditions and discusses the models from both simulation and tribological points of view. In papers B and C a simplified contact model, called the elastic foundation model, is used to model friction in a boundary-lubricated rolling and sliding contact. The model is integrated in a dynamic rigid body model of a mechanical system, the system behavior is simulated, and the result is compared with experimental results. Paper D discusses the application of the elastic foundation model to rough surface contact problems and investigates how the error in the elastic foundation results depends on surface roughness. / QC 20101129
2

Study and Analysis of Socio-behavioural Dynamics 
for Decision Support Systems in Smart Buildings

Garofalo, Paola 28 October 2019 (has links)
This thesis deals with the energy saving in smart building with focus on the impact of the user behaviour on the energy consumption. The problem of human behaviour modelling has been widely studied in the state of the art, but it is still an open problem in the field of smart building since the stochastic nature of the behaviour is difficult to be accurately represented by numerical tools. An interdisciplinary approach is proposed in order to identify the suitable user features from the psychological and social point of view and to integrate such a representation into a DSS for appliance scheduling and energy cost reduction. The proposed method has exploited location-based features of the users in order to represent their habits and needs and to compute the schedules that maximize the user acceptance toward an “energy-aware” behaviour. The obtained results point out a reduction of the peak-to-average ratio higher than 40% also considering the user constraints imposed by their presence into the building.
3

A method of analysis for the determination of system behavior through the analysis of time-series nominal data

Anklesaria, Kaiomars Phiroze January 1974 (has links)
No description available.
4

On interface modeling emphasis on friction

Söderberg, Anders January 2006 (has links)
<p>The general trend toward increased use of computer models and simulations during product development has led to a need for accurate and reliable product models. The function of many products relies on contact interfaces between interacting components. To simulate the behavior of such products, accurate models of both components and interfaces are required. Depending on the purpose of the simulation, interface models of different degrees of complexity are needed. In simulation of very large systems with many interfaces, it might be computationally expensive to integrate detailed models of each individual interface. Condensed models, or abstractions, that describe the interface properties with a minimum of degrees of freedom are therefore required.</p><p>This thesis deals with mechanical interfaces with an emphasis on friction. In the four appended papers friction models are discussed in terms of condensed models, as well as in terms of more detailed contact models. The aim is to study how friction can be modeled in behavioral simulation of products and to discuss the convenience and relevance of using different types of friction models as building blocks of a system model in behavioral simulations.</p><p>Paper<b> A </b>presents a review of existing condensed friction models for sliding contacts under different running conditions and discusses the models from both simulation and tribological points of view.</p><p>In papers<b> B </b>and <b>C</b> a simplified contact model, called the elastic foundation model, is used to model friction in a boundary-lubricated rolling and sliding contact. The model is integrated in a dynamic rigid body model of a mechanical system, the system behavior is simulated, and the result is compared with experimental results.</p><p>Paper <b>D</b> discusses the application of the elastic foundation model to rough surface contact problems and investigates how the error in the elastic foundation results depends on surface roughness.</p>
5

Paměťové a behaviorální vlivy biperidenu, M1-selektivního antagonisty, u laboratorního potkana / Mnemonic and behavioural effects of biperiden, an M1-selective antagonist, in the rat

Popelíková, Anna January 2017 (has links)
Due to the persisting lack of reliable animal models of cognitive impairment with good translational validity, researches strive to discover new ways and tools to replicate symptoms of human neurodegenerative diseases in rodents. Recently, biperiden, an M1- selective muscarinic antagonist, has been proposed as a potential tool for generating fast screening models of mnemonic deficits such as seen in patients with Alzheimer's disease. Being highly selective for the M1 receptor, a predominant type of muscarinic acetylcholine receptors in the brain involved in cognitive processes, it has been speculated to possibly only influence cognition without causing sensorimotor side effects. Studies assessing the usability of this drug reported conflicting results. We have decided to expand the experimental data and evaluate biperiden's validity in several variants of the Morris water maze. The results of this study showed no significant effect of biperiden on cognitive flexibility, tested by reversal learning. In delayed-matching-to-position paradigm, which tests assesses working memory, we found a difference in performance between the two experimental groups; however, it cannot be unequivocally attributed to a memory impairment. No effects were observed in visible platform task, confirming a lack of...
6

Diskrete-Elemente-Simulationen zum mehraxialen Schädigungsverhalten von Beton

Reischl, Dirk Sören 17 August 2022 (has links)
Die Methode der Diskreten Elemente ist eine neue, alte Methode, beruhend auf den Newtonschen Axiomen, praktikabel geworden durch die rasante Entwicklung der Rechentechnik in den vergangenen fünfzig Jahren. Es handelt sich um einfach zu beschreibende, vielfältig einsetzbare, aber rechenintensive Methode. Die Methode der Diskreten Elemente ist jene Methode, von der viele Menschen – nicht nur Laien -- glauben, dass es die Methode der Finiten Elemente sei. Die Methode ermöglicht es, mit vergleichsweise geringem Programmieraufwand spektakuläre Ergebnisse zu erzielen. Die Notwendigkeit zur Lösung schwach besetzter großer linearer Gleichungssysteme entfällt ebenso, wie eine komplizierte Netzgenerierung, die Assemblierung von Systemmatrizen und die damit verbundenen, aufwändigen Optimierungsstrategien. Die Methode der Diskreten Elemente gehorcht implizit streng jenen – stets gültigen – Energieprinzipien, auf die sich andere Methoden wie die Methode der Finiten Elemente bei Herleitungen explizit berufen, während sie tatsächlich lediglich mit Näherungen für (sehr) kleine Verformungen arbeiten. Bei entsprechender Auslegung lassen sich alle an der Simulation beteiligten Elemente als materielle Bestandteile oder beruhend auf der Wechselwirkung materieller Bestandteile auffassen. Kontaktelemente oder gar geeignet platzierte Risselemente werden nicht benötigt. Risse äußern sich durch die Abwesenheit von Materie. Das Phänomen der Überadditivität ist in Partikelsimulationen von vornherein angelegt. Partikelmethoden eignen sich daher hervorragend zum modellhaften Studium komplexer Systeme. Die Parameteridentifikation und Parameteranpassung von Diskrete-Elemente-Modellen gestaltet sich schwierig, sobald die Gültigkeit des Superpositionsprinzips nicht mehr gegeben ist. Dies ist jedoch kein Mangel der Methode, sondern Folge von Interaktion und Überadditivität. Die Methode eignet sich hervorragend zur Generierung virtueller Probekörper und zum Preprocessing im Zusammenwirken mit anderen Simulationsmethoden. Visualisierungen der mit Partikelmethoden erhaltenen Ergebnisse sind von hohem anschaulichem und didaktischem Wert. Die Methode ist sehr flexibel, so dass die Simulationsergebnisse bei entsprechender Parametergestaltung keiner künstlichen Überhöhung bedürfen. Die Methode der Diskreten Elemente ist eine entdeckende Methode. Sie besitzt – wie jede andere Methode – Methodencharakter, die auf ihrer Grundlage entwickelten Modelle – wie alle Modelle – Modellcharakter.
7

INTEGRATING ELECTRIC ROADWAYS INTO THE ELECTRIC POWER SYSTEM: A MULTI-SCALE SPATIOTEMPORAL EVALUATION

Diala Anwar Eid Haddad (17677794) 20 December 2023 (has links)
<p dir="ltr">Electric roadways (ERs) represent a new paradigm for electrified transportation that is</p><p dir="ltr">enabled by the emerging dynamic (in-motion) wireless power transfer technology. Large-scale</p><p dir="ltr">integration of DWPT systems into power grids can pose a problem due to its high-power</p><p dir="ltr">requirements, significant number of power electronic converters and spatial concentration.</p><p dir="ltr">Despite their potential magnitude, the operational impacts of DWPT on the power grid have</p><p dir="ltr">not been fully studied in the literature. This dissertation contributes to our understanding</p><p dir="ltr">of how ERs could be successfully integrated with the electric power system at a diverse range</p><p dir="ltr">of spatial and temporal levels.</p><p dir="ltr">On a macroscopic level, a framework for assessing the financial viability of ERs is proposed.</p><p dir="ltr">Annual ER load estimations from traffic flow models of electric vehicles are used to</p><p dir="ltr">generate energy forecasts and carry out a financial evaluation. These models are also used to</p><p dir="ltr">plan distribution system capacity expansion. On a mesoscopic level, a data-driven design of</p><p dir="ltr">ERs and their interconnection with the distribution grid is presented. A data-based stochastic</p><p dir="ltr">traffic flow model is developed and used for designing the interconnection of the DWPT</p><p dir="ltr">system with the distribution grid ensuring adequate power transmission to high penetration</p><p dir="ltr">levels of heavy-duty trucks. The model is also used for conducting a series of quasi-steady</p><p dir="ltr">state studies on the power distribution system. On a microscopic level, a methodology for</p><p dir="ltr">modeling ER systems for time-domain simulations is proposed. Dynamic component models</p><p dir="ltr">are developed for the DWPT system. Power electronics are modeled using average-value</p><p dir="ltr">representations and integrated with models of the distribution grid. The models are used for</p><p dir="ltr">time-domain system simulations, transient analysis, fault analysis and power quality studies.</p><p dir="ltr">Theoretical analysis as well as numerical case studies and simulations of the proposed</p><p dir="ltr">methodologies are presented.</p>
8

Assessment of rock mass quality and its effects on charge ability using drill monitoring technique

Ghosh, Rajib January 2017 (has links)
No description available.
9

Adaptive Eyes: Driver Distraction and Inattention PreventionThrough Advanced Driver Assistance Systems and Behaviour-Based Safety

Wege, Claudia 30 January 2014 (has links)
Technology pervades our daily living, and is increasingly integrated into the vehicle – directly affecting driving. On the one hand technology such as cell phones provoke driver distraction and inattention, whereas, on the other hand, Advanced Driver Assistance Systems (ADAS) support the driver in the driving task. The question is, can a driver successfully adapt to the ever growing technological advancements? Thus, this thesis aimed at improving safe driver behaviour by understanding the underlying psychological mechanisms that influence behavioural change. Previous research on ADAS and human attention was reviewed in the context of driver behavioural adaptation. Empirical data from multiple data sources such as driving performance data, visual behaviour data, video footage, and subjective data were analyzed to evaluate two ADAS (a brake-capacity forward collision warning system, B-FCW, and a Visual Distraction Alert System, VDA-System). Results from a field operational test (EuroFOT) showed that brake-capacity forward collision warnings lead to immediate attention allocation toward the roadway and drivers hit the brake, yet change their initial response later on by directing their eyes toward the warning source in the instrument cluster. A similar phenomenon of drivers changing initial behaviour was found in a driving simulator study assessing a Visual Distraction Alert System. Analysis showed that a Visual Distraction Alert System successfully assists drivers in redirecting attention to the relevant aspects of the driving task and significantly improves driving performance. The effects are discussed with regard to behavioural adaptation, calibration and system acceptance. Based on these findings a novel assessment for human-machine-interaction (HMI) of ADAS was introduced. Based on the contribution of this thesis and previous best-practices, a holistic safety management model on accident prevention strategies (before, during and after driving) was developed. The DO-IT BEST Feedback Model is a comprehensive feedback strategy including driver feedback at various time scales and therefore is expected to provide an added benefit for distraction and inattention prevention. The central contributions of this work are to advance research in the field of traffic psychology in the context of attention allocation strategies, and to improve the ability to design future safety systems with the human factor in focus. The thesis consists of the introduction of the conducted research, six publications in full text and a comprehensive conclusion of the publications. In brief this thesis intends to improve safe driver behaviour by understanding the underlying psychological mechanisms that influence behavioral change, thereby resulting in more attention allocation to the forward roadway, and improved vehicle control.:Abstract i Zusammenfassung iii List of included publications v Acknowledgements vii Previously published work ix Table of contents xi Preface xii 1 Chapter 1 Introduction 1 1.1 Outline 1 1.2 Objectives 2 1.3 Background 8 1.3.1 Behavioural adaption to ADAS 8 1.3.2 Driver distraction and inattention 9 2 Chapter 2 Paper I 23 3 Chapter 3 Paper II 47 4 Chapter 4 Paper III 61 5 Chapter 5 Paper IV 91 6 Chapter 6 Paper V 117 7 Chapter 7 Paper VI 143 8 Chapter 8 Conclusions and discussion 161 8.1. Contributions 161 8.2. Implications 171 8.3. Limitations and research needs 173 9 References 177 Curriculum Vitae 199 Eidesstattliche Erklärung 201 / Technologie durchdringt unser tägliches Leben und ist zunehmend integriert in Fahrzeuge – das Resultat sind veränderte Anforderungen an Fahrzeugführer. Einerseits besteht die Gefahr, dass er durch die Bedienung innovativer Technologien (z.B. Mobiltelefone) unachtsam wird und visuell abgelenkt ist, andererseits kann die Nutzung von Fahrerassistenzsystemen die den Fahrer bei der Fahraufgabe unterstützten einen wertvollen Beitrag zur Fahrsicherheit bieten. Die steigende Aktualität beider Problematiken wirft die Frage auf: "Kann der Fahrer sich erfolgreich dem ständig wachsenden technologischen Fortschritt anpassen?" Das Ziel der vorliegenden Arbeit ist der Erkenntnisgewinn zur Verbesserung des Fahrverhaltens indem der Verhaltensänderungen zugrunde liegende psychologische Mechanismen untersucht werden. Eine Vielzahl an Literatur zu Fahrerassistenzsystemen und Aufmerksamkeitsverteilung wurde vor dem Hintergrund von Verhaltensanpassung der Fahrer recherchiert. Daten mehrerer empirischer Quellen, z. B. Fahrverhalten, Blickbewegungen, Videomitschnitte und subjektive Daten dienten zur Datenauswertung zweier Fahrerassistenzsysteme. Im Rahmen einer Feldstudie zeigte sich, dass Bremskapazitäts-Kollisionswarnungen zur sofortigen visuellen Aufmerksamkeitsverteilung zur Fahrbahn und zum Bremsen führen, Fahrer allerdings ihre Reaktion anpassen indem sie zur Warnanzeige im Kombinationsinstrument schauen. Ein anderes Phänomen der Verhaltensanpassung wurde in einer Fahrsimulatorstudie zur Untersuchung eines Ablenkungswarnsystems, das dabei hilft die Blicke von Autofahrern stets auf die Straße zu lenken, gefunden. Diese Ergebnisse weisen nach, dass solch ein System unterstützt achtsamer zu sein und sicherer zu fahren. Die vorliegenden Befunde wurden im Zusammenhang zu Vorbefunden zur Verhaltensanpassung zu Fahrerassistenzsystemen, Fahrerkalibrierung und Akzeptanz von Technik diskutiert. Basierend auf den gewonnenen Erkenntnissen wurde ein neues Vorgehen zur Untersuchung von Mensch- Maschine-Interaktion eingeführt. Aufbauend auf den Resultaten der vorliegenden Arbeit wurde ein ganzheitliches Modell zur Fahrsicherheit und -management, das DO-IT BEST Feedback Modell, entwickelt. Das Modell bezieht sich auf multitemporale Fahrer-Feedbackstrategien und soll somit einen entscheidenen Beitrag zur Verkehrssicherheit und dem Umgang mit Fahrerunaufmerksamkeit leisten. Die zentralen Beiträge dieser Arbeit sind die Gewinnung neuer Erkenntnisse in den Bereichen der Angewandten Psychologie und der Verkehrspsychologie in den Kontexten der Aufmerksamkeitsverteilung und der Verbesserung der Gestaltung von Fahrerassistenzsystemen fokusierend auf den Bediener. Die Dissertation besteht aus einem Einleitungsteil, drei empirischen Beiträgen sowie drei Buchkapiteln und einer abschliessenden Zusammenfassung.:Abstract i Zusammenfassung iii List of included publications v Acknowledgements vii Previously published work ix Table of contents xi Preface xii 1 Chapter 1 Introduction 1 1.1 Outline 1 1.2 Objectives 2 1.3 Background 8 1.3.1 Behavioural adaption to ADAS 8 1.3.2 Driver distraction and inattention 9 2 Chapter 2 Paper I 23 3 Chapter 3 Paper II 47 4 Chapter 4 Paper III 61 5 Chapter 5 Paper IV 91 6 Chapter 6 Paper V 117 7 Chapter 7 Paper VI 143 8 Chapter 8 Conclusions and discussion 161 8.1. Contributions 161 8.2. Implications 171 8.3. Limitations and research needs 173 9 References 177 Curriculum Vitae 199 Eidesstattliche Erklärung 201

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