Dissertations / Theses: 'SimulationX'

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Heinrich, Stefan. "Modulbasierte Untersuchungen ebener Koppelgetriebe in SimulationX." Universitätsbibliothek Chemnitz, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-qucosa-206901.

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Im Rahmen eines Kurzvortrages wurden die grundlegenden Zusammenhänge zwischen dem Prinzip von Modelica und SimulationX erläutert. Der Fokus liegt hierbei auf der Einführung in die Systemsimulation mit Funktionalität von Modelica. Die genutzte Software SimulationX wird in ihren Grundzügen vorgestellt und es sind Vorgehensempfehlungen zur Modellbildung innerhalb solcher Programmumgebungen enthalten. Durch die Modularität des Programms ergeben sich für den Anwender neue Möglichkeiten in der Simulation komplexer Mechanismen. Durch eine gezielte Verknüpfung von Analyse- und Synthesemodulen mit Optimierungsalgorithmen, kann so ein intelligentes Berechnungssystem geschaffen werden. Dies ermöglicht methodisch neue Auslegungsstrategien ebener Koppelgetriebe mit dynamischen Anforderungen.

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2

Frenzel, Erik. "Co-Simulation von LIGGGHTS® und SimulationX® zur Simulation des Zerkleinerungsprozesses in Brechern." Universitätsbibliothek Chemnitz, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-qucosa-206919.

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In vielen Bereichen der Tagebautechnik spielt die Zerkleinerung von Material/ -strömen eine wesentliche Rolle, wobei sich je nach Material verschiedene Anforderungen an das Brechersystem ergeben. In Folge dessen werden Brecher auftragsspezifisch, meist für einen speziellen Gesteinstyp oder Einsatzort entwickelt oder modifiziert. Eine aussagekräftige Prognose der im Bruchprozess auftretenden Lasten auf den Brecher ist somit essentieller Bestandteil im Entwicklungsprozess. Ein viel versprechender Ansatz, um das Materialverhalten in der Lastprognose zu berücksichtigen, ist die numerische Simulation des Materialbruchverhaltens mit Hilfe der Diskreten-Elemente-Methode (DEM). Das Verhalten der sogenannten Partikel wird über Kontakt- und bond-Modelle beschrieben und soll das makroskopische Verhalten des jeweiligen Gesteins möglichst realitätsnah abbilden. Die Problematik ist, dass in SimulationX® keine Module zur DEM-Simulation vorhanden sind und umgekehrt in der DEM-Simulationsumgebung LIGGGHTSG® (LAMMPS improved for general granular and granular heat transfer simulations) keine derartige Maschinensimulation möglich ist. Der Ausweg ist die Co-Simulation zweier unterschiedlicher Simulationsumgebungen durch die Nutzung des ,,Functional Mock-Up Interface“-Standards (FMI). Berechnungsergebnis sind die dynamischen Lasten auf den Brecher unter Berücksichtigung des Materialverhaltens. Somit können früher in der Brecherentwicklung Prognosen zu auftretenden Lasten getroffen und Einflussuntersuchungen von Maschinenkonfigurationen zur Effizienzsteigerungen durchgeführt werden, was zuvor auf Grund des Einzelanfertigungscharakters nicht möglich oder nicht wirtschaftlich war.

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3

Heinrich, Stefan. "Analyse und Synthese ebener Koppelgetriebe in SimulationX." Technische Universität Chemnitz, 2018. https://monarch.qucosa.de/id/qucosa%3A21438.

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Der Begriff der Maßsynthese bezieht sich auf die Anwendung bestimmter geometrischer Verfahren zur Maßbestimmung ebener Koppelgetriebe und ist im klassischen Maschinenbau ein Baustein bei der Entwicklung von Antriebssystemen zur Erzeugung nichtlinearer Bewegungen. Eben jener Entwicklungsprozess ist jedoch durch ein streng hierarchisches Vorgehen geprägt. So erfolgt nach der Maßbestimmung die Dimensionierung des Mechanismus und anschließend dessen kinetische Betrachtung. Bisherige Arbeiten auf dem Gebiet der Mechanismendynamik, -synthese und -optimierung behandeln die einzelnen Schritte losgelöst voneinander. Gelenkabstände und Gliedwinkel ebener Koppelgetriebe werden, beispielsweise bei einem dynamischen Ausgleich, als unveränderlich betrachtet. Auf der anderen Seite gibt es keine praktischen Ansätze zur kinetischen Beurteilung der Lösungen während der Maßsynthese, was vor allem auf die zum Zeitpunkt der Synthese unbekannten Masseparameter zurückzuführen ist. Ziel der Untersuchungen und Gegenstand des Vortrages ist ein neuer Ansatz, welcher auf Basis eines modularen Synthesekonzeptes innerhalb eines Systemsimulators die Betrachtung kinetischer Kenngrößen, wie Gelenkkräfte, Energiebilanz, Gelenkspiel oder FFT während der Synthese ermöglicht. Dieser kontinuierliche Analyse-Synthese-Parameter-Abgleich (ASPA) ermöglicht die Optimierung des Mechanismus während der Synthese unter Berücksichtigung kinetischer Kenngrößen. Neben der Vorstellung des modularen Synthesekonzeptes werden Möglichkeiten zur Beschreibung der Masseparameter während der Synthese und Wege zur Optimierung der freien Parameter dargestellt.

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4

Burkhard, Adam. "Komplexe Systeme mit dynamischem, nichtlinearem Verhalten durch Simulation verstehen und optimieren." Universitätsbibliothek Chemnitz, 2017. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-qucosa-225834.

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Wo FEM- und CFD-Analysen präzise Aussagen über einzelne Bauteile und überschaubare Baugruppen liefern, untersucht die dynamische Systemsimulation zeitveränderliche Vorgänge ganzer Systeme. Diese Systeme können auch aus Komponenten unterschiedlicher physikalischer Domänen bestehen. Somit lassen sich zum Beispiel die Wechselwirkungen und resultierenden Effekte aus Regelstrecken gekoppelt mit mechanischen, hydraulischen und oder elektrischen Strukturen komfortabel in nur einem Modell auf einer Plattform betrachten.

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Krückeberg, Nico. "Von der Idee über die Entwicklung bis zum virtuellen Test : Mit ESI ́s SimulationX in die elektromobile Zukunft." Technische Universität Chemnitz, 2018. https://monarch.qucosa.de/id/qucosa%3A21508.

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Wie hoch ist die Leistungsdichte, Energieeffizienz, Fahrdynamik oder der Fahrkomfort? Wie wirken unterschiedliche, physikalische Systeme zusammen und wie können die mechatronischen Zusammenhänge verständlich dargestellt werden? Solche und andere Fragestellungen tauchen im Entwicklungsprozess immer wieder auf und lassen sich nur schwer zufriedenstellend beantworten. Die Systemsimulation liefert da einen effizienten Ansatz, welcher es dem Entwicklungsingenieur ermöglicht bereits in der Konzeptphase virtuelle Prototypen zu erstellen. Mit diesen kann dann das physikalische Verhalten simuliert, analysiert und anschließend optimiert werden. Dadurch ergibt sich bereits in den frühen Phasen der Produktentwicklung die Möglichkeit, alle zukünftigen Entscheidungen auf einer validen Basis zu treffen. ESI ́s SimulationX liefert für diese Anwendungsfälle eine umfassende softwaretechnische Lösung. Besonders im Bereich der E- Mobility sowie ihrer Peripherie ermöglicht die Software mit seinen anwendungsspezifischen Modellbibliotheken eine ganzheitliche Betrachtung.

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6

Heinrich, Stefan. "Parameterstudien und Co-Simulation ebener Koppelgetriebe." Universitätsbibliothek Chemnitz, 2017. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-qucosa-225974.

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Im Vortrag geht es um die Erstellung von Berechnungsmodellen zur Simulation ebener Koppelgetriebe in SimulationX. Der Fokus liegt hierbei auf der vollparametrischen Modellsteuerung während der Getriebesynthese in SimulationX. Neben Möglichkeiten zur Steuerung und Variation der Simulationsmodelle während der Berechnung wird die Entwicklung von Berechnungsmodulen zur Individualisierung des Berechnungsprozesses vorgestellt. Möglichkeiten zur Steuerung der Simulation und Co-Simulation bei anderen Programmen ist ebenfalls Thema weiterer Ansätze zur domänenübergreifenden Gesamtsimulation von Koppelgetrieben.

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7

Berger, Maik. "10. SAXON SIMULATION MEETING : Präsentationen und Vorträge des 10. Anwendertreffens am 22. März 2018 an der Technischen Universität Chemnitz." Technische Universität Chemnitz, 2018. https://monarch.qucosa.de/id/qucosa%3A21380.

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Von der Professur Montage- und Handhabungstechnik der Fakultät für Maschinenbau der Technischen Universität Chemnitz wird seit 2009 das jährliche Simulationsanwendertreffen SAXSIM organisiert. Ausgewählte Beiträge werden in Form eines Tagungsbandes veröffentlicht. Das 10. Anwendertreffen SAXSIM fand am 22.03.2018 an der TU Chemnitz statt.
The Chair of Assembly and Handling Technology, which belongs to the Faculty of Mechanical Engineering, has organized the annual simulation user meeting SAXSIM since 2009. Select contributions will be published in conference proceedings. The 10th SAXSIM user meeting took place at Technische Universität Chemnitz on March 22, 2018.

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Berger, Maik. "11. SAXON SIMULATION MEETING : Präsentationen und Vorträge des 11. Anwendertreffens am 26. März 2019 an der Technischen Universität Chemnitz." Technische Universität Chemnitz, 2019. https://monarch.qucosa.de/id/qucosa%3A34090.

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Von der Professur Montage- und Handhabungstechnik der Fakultät für Maschinenbau der Technischen Universität Chemnitz wird seit 2009 das jährliche Simulationsanwendertreffen SAXSIM organisiert. Ausgewählte Beiträge werden in Form eines Tagungsbandes veröffentlicht. Das 11. Anwendertreffen SAXSIM fand am 26.03.2019 an der TU Chemnitz statt.
The Chair of Assembly and Handling Technology, which belongs to the Faculty of Mechanical Engineering, has organized the annual simulation user meeting SAXSIM since 2009. Select contributions will be published in conference proceedings. The 11th SAXSIM user meeting took place at Technische Universität Chemnitz on March 26, 2019.

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9

Berger, Maik. "9. SAXON SIMULATION MEETING : Präsentationen und Vorträge des 9. Anwendertreffens am 28. März 2017 an der Technischen Universität Chemnitz." Universitätsverlag der Technischen Universität Chemnitz, 2017. https://monarch.qucosa.de/id/qucosa%3A20708.

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Von der Professur Montage- und Handhabungstechnik der Fakultät für Maschinenbau der Technischen Universität Chemnitz wird seit 2009 das jährliche Simulationsanwendertreffen SAXSIM organisiert. Ausgewählte Beiträge werden in Form eines Tagungsbandes veröffentlicht. Das 9. Anwendertreffen SAXSIM fand am 28.03.2017 an der TU Chemnitz statt.:- Multiphysikalische Systemsimulation mit SimulationX / Adam Burkhard - Modellierung & Simulation des Plasmaschweißens zur Entwicklung innovativer Schweißbrenner / Dr.-Ing. habil. Khaled Alaluss - Dynamischer Partikelbruch: Modelldefinition, Kalibrierung und Anwendung / Dr.-Ing. Luca Benvenuti - Konstruktionsbegleitende Toleranzsimulation mit CETOL 6 σ unter Verwendung der GPS-Strategie DIN EN ISO 14638 und DIN EN ISO 8015 / Dipl.-Ing. (FH) Christoph Bruns - PTC CREO SIMULATE ENGINE UPDATES / Dr. Arun Chavan - CREO SIMULATE : ROADMAP / Jose Coronado - Simulationsbasierte Entwicklung und Optimierung von Werkzeugmaschinen / Dipl.-Ing. Uwe Eiselt - Validierung des Kontaktmoduls der Freeware Z88Aurora anhand analytischer Beispiele und kommerzieller FE-Systeme / Christian Glenk M.Sc. - Mehrkörpersimulation eines ebenen Koppelgetriebes mittels Matlab/ADAMS-Co-Simulation / Dipl.-Ing. Christian Gollee - Numerische Auslegung des Mehrlagenschweißens als additives Fertigungsverfahren / Dr.-Ing. Marcel Graf - Berechnung und Simulation von Kurvenschrittgetrieben / Dr.-Ing. Andreas Heine - Parameterstudien und Co-Simulation ebener Koppelgetriebe / Stefan Heinrich M.Sc. - Erfassung, Simulation und Weiterverarbeitung menschlicher Bewegungen mit DYNAMICUS / Dipl. -Math. Heike Hermsdorf - Linear Dynamic System Analyses with Creo Simulate / Dr.-Ing. Roland Jakel - Strömungssimulation zur Optimierung von Flussfeldern in PEM-Brennstoffzellen / Philipp Jendras M.Sc. - Konvergenz eines plastischen Multiphysics-Kontaktes in der Pressschweißsimulation - Herausforderungen und Lösungsansätze / Jonny Kaars M.Eng. - Kurvenabgleich zur Bestimmung eines Systemverhalten und von Materialparametern / Dipl.-Ing. Rene Kallmeyer - Die kinematische und statische Analyse eines Biglide-Getriebes mit Hilfe der Programme Mathcad und GeoGebra / Dr.-Ing. Hanfried Kerle - Möglichkeiten der TexMind Software für Generierung von textilen Strukturen für FEM Simulationen und CAD Anwendungen / Prof. Dr. Yordan Kyosev - Prozesssimulation einer Rotorflechtmaschine nach „Horn“ zur Ermittlung der Flechtfadenspannung / Robert Laue M.Sc. ; Dr.-Ing. Daniel Denninger - Bruch einer Königswelle einer 6300 t Presse / Prof. Dr-Ing. Uwe Mahn - Strukturzuverlässigkeit durch Frequenzganganalyse mit Finite-Elemente-Methode im Rahmen des Projektes DRESDYN / Dipl.-Ing. M.Eng. Anton Melnikov - Systemübergreifender Simulationsansatz zur Auslegung, Fertigung und Qualitätssicherung am Beispiel einer Bogenverzahnung / Dipl.-Ing. Jürgen Merz - Integrative Prozess- und Bauteilsimulation für kurzfaserverstärkte Spritzgießbauteile / Dr.-Ing. Sascha Müller - Computergestützte Simulationsschnittstelle - Optimierte Systementwicklung / Dipl.-Ing. Sam Nezhat - Formatabhängige hochdynamische Bewegungen mit Servoantrieben / Dipl.-Ing. Dipl.-Inform. Rainer Nolte - Integration der Diskrete Elemente Methode in die domänen-übergreifende Systemsimulation / Dipl.-Ing. Christian Richter - Mehrkörpermodellierung und Validierung einer 3 MW Windturbine / Andreas Schulze M. Sc. - Vergleich von Stützstrukturen für die additive Fertigung: Creo Parametric/Simulate 4.0 & ProTOpCI / Dipl.-Ing. (FH) Urs Simmler - MFBD-Simulation des Nadeleindringens in ein Gewebephantom am Beispiel der Stanzbiopsie / Thorsten Speicher M.Eng. ; Katharina Hauschild M.Sc. - ANSYS AIM: Der Konzeptsimulator für alle / Dipl.-Ing. Marc Vidal - Neue Schweißfunktionalität in Creo 4 mit den daraus entstehenden Vorteilen zur Simulation / Axel Waidmann - Entwicklung eines zwangläufigen Schneid- und Fixiersystems für den Einsatz in einem Tapelegekopf / Dipl.-Ing. Rainer Wallasch
The Chair of Assembly and Handling Technology, which belongs to the Faculty of Mechanical Engineering, has organized the annual simulation user meeting SAXSIM since 2009. Select contributions will be published in conference proceedings. The 9th SAXSIM user meeting took place at Technische Universität Chemnitz on March 28, 2017.:- Multiphysikalische Systemsimulation mit SimulationX / Adam Burkhard - Modellierung & Simulation des Plasmaschweißens zur Entwicklung innovativer Schweißbrenner / Dr.-Ing. habil. Khaled Alaluss - Dynamischer Partikelbruch: Modelldefinition, Kalibrierung und Anwendung / Dr.-Ing. Luca Benvenuti - Konstruktionsbegleitende Toleranzsimulation mit CETOL 6 σ unter Verwendung der GPS-Strategie DIN EN ISO 14638 und DIN EN ISO 8015 / Dipl.-Ing. (FH) Christoph Bruns - PTC CREO SIMULATE ENGINE UPDATES / Dr. Arun Chavan - CREO SIMULATE : ROADMAP / Jose Coronado - Simulationsbasierte Entwicklung und Optimierung von Werkzeugmaschinen / Dipl.-Ing. Uwe Eiselt - Validierung des Kontaktmoduls der Freeware Z88Aurora anhand analytischer Beispiele und kommerzieller FE-Systeme / Christian Glenk M.Sc. - Mehrkörpersimulation eines ebenen Koppelgetriebes mittels Matlab/ADAMS-Co-Simulation / Dipl.-Ing. Christian Gollee - Numerische Auslegung des Mehrlagenschweißens als additives Fertigungsverfahren / Dr.-Ing. Marcel Graf - Berechnung und Simulation von Kurvenschrittgetrieben / Dr.-Ing. Andreas Heine - Parameterstudien und Co-Simulation ebener Koppelgetriebe / Stefan Heinrich M.Sc. - Erfassung, Simulation und Weiterverarbeitung menschlicher Bewegungen mit DYNAMICUS / Dipl. -Math. Heike Hermsdorf - Linear Dynamic System Analyses with Creo Simulate / Dr.-Ing. Roland Jakel - Strömungssimulation zur Optimierung von Flussfeldern in PEM-Brennstoffzellen / Philipp Jendras M.Sc. - Konvergenz eines plastischen Multiphysics-Kontaktes in der Pressschweißsimulation - Herausforderungen und Lösungsansätze / Jonny Kaars M.Eng. - Kurvenabgleich zur Bestimmung eines Systemverhalten und von Materialparametern / Dipl.-Ing. Rene Kallmeyer - Die kinematische und statische Analyse eines Biglide-Getriebes mit Hilfe der Programme Mathcad und GeoGebra / Dr.-Ing. Hanfried Kerle - Möglichkeiten der TexMind Software für Generierung von textilen Strukturen für FEM Simulationen und CAD Anwendungen / Prof. Dr. Yordan Kyosev - Prozesssimulation einer Rotorflechtmaschine nach „Horn“ zur Ermittlung der Flechtfadenspannung / Robert Laue M.Sc. ; Dr.-Ing. Daniel Denninger - Bruch einer Königswelle einer 6300 t Presse / Prof. Dr-Ing. Uwe Mahn - Strukturzuverlässigkeit durch Frequenzganganalyse mit Finite-Elemente-Methode im Rahmen des Projektes DRESDYN / Dipl.-Ing. M.Eng. Anton Melnikov - Systemübergreifender Simulationsansatz zur Auslegung, Fertigung und Qualitätssicherung am Beispiel einer Bogenverzahnung / Dipl.-Ing. Jürgen Merz - Integrative Prozess- und Bauteilsimulation für kurzfaserverstärkte Spritzgießbauteile / Dr.-Ing. Sascha Müller - Computergestützte Simulationsschnittstelle - Optimierte Systementwicklung / Dipl.-Ing. Sam Nezhat - Formatabhängige hochdynamische Bewegungen mit Servoantrieben / Dipl.-Ing. Dipl.-Inform. Rainer Nolte - Integration der Diskrete Elemente Methode in die domänen-übergreifende Systemsimulation / Dipl.-Ing. Christian Richter - Mehrkörpermodellierung und Validierung einer 3 MW Windturbine / Andreas Schulze M. Sc. - Vergleich von Stützstrukturen für die additive Fertigung: Creo Parametric/Simulate 4.0 & ProTOpCI / Dipl.-Ing. (FH) Urs Simmler - MFBD-Simulation des Nadeleindringens in ein Gewebephantom am Beispiel der Stanzbiopsie / Thorsten Speicher M.Eng. ; Katharina Hauschild M.Sc. - ANSYS AIM: Der Konzeptsimulator für alle / Dipl.-Ing. Marc Vidal - Neue Schweißfunktionalität in Creo 4 mit den daraus entstehenden Vorteilen zur Simulation / Axel Waidmann - Entwicklung eines zwangläufigen Schneid- und Fixiersystems für den Einsatz in einem Tapelegekopf / Dipl.-Ing. Rainer Wallasch

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10

Volek, Matěj. "Implementace zátěžného stavu “Creeping” do multi-body simulace." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2018. http://www.nusl.cz/ntk/nusl-382566.

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Tato diplomová práce je zaměřena na implementaci procesu simulace zatěžovacího zatížení do stávajícího rozhraní používaného pro multi-body simulace hnacího vozidla. „Creeping“ bylo definováno jako řízení vozidla bez nárazu na plynový pedál v nízkých převodech. Bylo rozhodnuto simulovat tento stav zavedením sil Jízdních odporů – Aerodynamická odporová síla Fa, síla Valivého odporu Fr a horizontální část Gravitační síly Fgx. Tyto síly byly modelovány v softwaru SimulationX a byl definován model pro zatížení „Creeping“ – ten byl založen na změně stoupání kopce, což dalo výsledky potřebné pro analýzu chování při stavu „Creeping“. Poté byly vytvořeny soubory v softwaru Matlab potřebné pro běh a následné zpracování simulace, které analyzují výsledky v závislosti na čase nebo průměrném točivém momentu motoru. Potom byla správnost procesu kontrolována ve srovnání s experimentálními daty. Toto srovnání ukázalo, že proces pracuje bez velkých problémů; výsledky vykazovaly podobný trend, byly ale ovlivněny nedostatkem vstupních dat z experimentu.

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11

Dave, Jagrut Durdant. "Parallel Discrete Event Simulation Techniques for Scientific Simulations." Thesis, Georgia Institute of Technology, 2005. http://hdl.handle.net/1853/6942.

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Exponential growth in computer technology, both in terms of individual CPUs and parallel technologies over the past decades has triggered rapid progress in large scale simulations. However, despite these achievements it has become clear that many conventional state-of-the-art techniques are ill-equipped to tackle problems that inherently involve multiple scales in configuration space. Our difficulty is that conventional ("time driven" or "time stepped") techniques update all parts of simulation space (fields, particles) synchronously, i.e. at time intervals assumed to be the same throughout the global computation domain or at best varying on a sub-domain basis (in adaptive mesh refinement algorithms). Using a serial electrostatic model, it was recently shown that discrete event techniques can lead to more than two orders of magnitude speedup compared to the time-stepped approach. In this research, the focus is on the extension of this technique to parallel architectures, using parallel discrete event simulation. Previous research in parallel discrete event simulations of scientific phenomena has been limited This thesis outlines a technique for converting a time-stepped simulation in the scientific domain into an equivalent parallel discrete event model. As a candidate simulation, an electromagnetic hybrid plasma simulation is considered. The experiments and analysis show the trade-offs on performance by varying the following factors: the simulations model characteristics (e.g. lookahead), applications load balancing, and accuracy of simulation results. The experiments are performed on a high performance cluster, using a conservative synchronization mechanism. Initial performance results are encouraging, demonstrating very good parallel speedup for large-scale model configurations containing tens of thousands of cells. Overheads for inter-processor communication remain a challenge for smaller computations.

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12

Linke, Gunnar Torsten. "Eigenschaften fluider Vesikeln bei endlichen Temperaturen." Phd thesis, Universität Potsdam, 2005. http://opus.kobv.de/ubp/volltexte/2005/583/.

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In der vorliegenden Arbeit werden die Eigenschaften geschlossener fluider Membranen, sogenannter Vesikeln, bei endlichen Temperaturen untersucht. Dies beinhaltet Betrachtungen zur Form freier Vesikeln, eine Untersuchung des Adhäsionsverhaltens von Vesikeln an planaren Substraten sowie eine Untersuchung der Eigenschaften fluider Vesikeln in eingeschränkten Geometrien. Diese Untersuchungen fanden mit Hilfe von Monte-Carlo-Simulationen einer triangulierten Vesikeloberfläche statt. Die statistischen Eigenschaften der fluktuierenden fluiden Vesikeln wurden zum Teil mittels Freier-Energie-Profile analysiert. In diesem Zusammenhang wurde eine neuartige Histogrammethode entwickelt.

Die Form für eine freie fluide Vesikel mit frei veränderlichem Volumen, die das Konfigurationsenergie-Funktional minimiert, ist im Falle verschwindender Temperatur eine Kugel. Mit Hilfe von Monte-Carlo-Simulationen sowie einem analytisch behandelbaren Modellsystem konnte gezeigt werden, daß sich dieses Ergebnis nicht auf endliche Temperaturen verallgemeinern lässt und statt dessen leicht prolate und oblate Vesikelformen gegenüber der Kugelgestalt überwiegen. Dabei ist die Wahrscheinlichkeit für eine prolate Form ein wenig gröoßer als für eine oblate. Diese spontane Asphärizität ist entropischen Ursprungs und tritt nicht bei zweidimensionalen Vesikeln auf. Durch osmotische Drücke in der Vesikel, die größer sind als in der umgebenden Flüssigkeit, lässt sich die Asphärizität reduzieren oder sogar kompensieren. Die Übergänge zwischen den beobachteten prolaten und oblaten Formen erfolgen im Bereich von Millisekunden in Abwesenheit osmotisch aktiver Partikel. Bei Vorhandensein derartiger Partikel ergeben sich Übergangszeiten im Bereich von Sekunden.

Im Rahmen der Untersuchung des Adhäsionsverhaltens fluider Vesikeln an planaren, homogenen Substraten konnte mit Hilfe von Monte-Carlo-Simulationen festgestellt werden, dass die Eigenschaften der Kontaktfläche der Vesikeln stark davon abhängen, welche Kräfte den Kontakt bewirken. Für eine dominierende attraktive Wechselwirkung zwischen Substrat und Vesikelmembran sowie im Falle eines Massendichteunterschieds der Flüssigkeiten innerhalb und außerhalb der Vesikel, der die Vesikel auf das Substrat sinken lässt, ndet man innerhalb der Kontakt ache eine ortsunabhangige Verteilung des Abstands zwischen Vesikelmembran und Substrat. Drückt die Vesikel ohne Berücksichtigung osmotischer Effekte auf Grund einer Differenz der Massendichten der Membran und der umgebenden Flüssigkeit gegen das Substrat, so erhält man eine Abstandsverteilung zwischen Vesikelmembran und Substrat, die mit dem Abstand vom Rand der Kontaktfläche variiert. Dieser Effekt ist zudem temperaturabhängig.

Ferner wurde die Adhäsion fluider Vesikeln an chemisch strukturierten planaren Substraten untersucht. Durch das Wechselspiel von entropischen Eekten und Konfigurationsenergien entsteht eine komplexe Abhängigkeit der Vesikelform von Biegesteifigkeit, osmotischen Bedingungen und der Geometrie der attraktiven Domänen.

Für die Bestimmung der Biegesteifigkeit der Vesikelmembranen liefern die existierenden Verfahren stark voneinander abweichende Ergebnisse. In der vorliegenden Arbeit konnte mittels Monte-Carlo-Simulationen zur Bestimmung der Biegesteifigkeit anhand des Mikropipettenverfahrens von Evans gezeigt werden, dass dieses Verfahren die a priori für die Simulation vorgegebene Biegesteifigkeit im wesentlichen reproduzieren kann.

Im Hinblick auf medizinisch-pharmazeutische Anwendungen ist der Durchgang fluider Vesikeln durch enge Poren relevant. In Monte-Carlo-Simulationen konnte gezeigt werden, dass ein spontaner Transport der Vesikel durch ein Konzentrationsgefälle osmotisch aktiver Substanzen, das den physiologischen Bedingungen entspricht, induziert werden kann. Es konnten die hierfür notwendigen osmotischen Bedingungen sowie die charakteristischen Zeitskalen abgeschätzt werden. Im realen Experiment sind Eindringzeiten in eine enge Pore im Bereich weniger Minuten zu erwarten. Ferner konnte beobachtet werden, dass bei Vesikeln mit einer homogenen, positiven spontanen Krümmung Deformationen hin zu prolaten Formen leichter erfolgen als bei Vesikeln ohne spontane Krümmung. Mit diesem Effekt ist eine Verringerung der Energiebarriere für das Eindringen in eine Pore verbunden, deren Radius nur wenig kleiner als der Vesikelradius ist.
In this thesis, the properties of closed fluid membranes or vesicles are studied at finite temperatures. The work contains investigations of the shape of free vesicles, studies of the adhesion behavior of vesicles to planar substrates, and investigations of the properties of fluid vesicles in confined geometries. The investigations have been performed with Monte Carlo simulations of triangulated vesicles. The statistical properties of fluctuating vesicles have been analyzed in detail by means of free energy profiles. In this context, a new histogram method was developed.

The shape of minimum configurational energy for a free vesicle without volume constraint at zero temperature is a sphere. It is shown by means of Monte Carlo simulations and a model which can be analyzed analytically, that this result does not apply to finite temperatures. Instead, prolate and oblate shapes prevail and the probability for a prolate shape is slightly larger than that for an oblate shape. This spontaneous asphericity is of entropic origin and cannot be observed in two dimensions. Osmotic pressures inside the vesicle that are larger than in the surrounding liquid may reduce or even compensate the asphericity. The transitions between the observed prolate and oblate states occur on the time scale of milliseconds in the absence of osmotically active particles and on the time scale of seconds in the presence of osmotically active particles.

As far as the adhesion behavior of fluid vesicles to planar homogeneous substrates is concerned, Monte Carlo simulations reveal a strong dependence of the properties of the contact area on its driving force. In the case of a dominating attractive interaction between vesicle membran and substrate as well as for a mass density difference of the liquids inside and outside the vesicle, which push the vesicle against the substrate, the distribution of the distance between the vesicle membrane and the substrate is homogenous. If the vesicle is pushed against the substrate by a difference of the mass densities of the membrane and the surrounding liquid, neglecting all osmotic effects, one gets a distance distribution between the vesicle membrane and the substrate which varies with the distance from the rim of the contact area. Moreover, this effect is temperature-dependent.

Furthermore, the adhesion of fluid vesicles to chemically structured planar substrates has been studied. The interplay between entropic effects and configurational energies causes a complex dependence of the vesicle shape on the bending rigidity, osmotic conditions, and the geometry of the attractive domains.

There are several experimental methods for measuring the bending rigidity of vesicle membranes which lead to rather different results for the numerical value. Monte Carlo simulations of Evans' micropipette method show that the difference between the measured bending rigidity and the a priori chosen bending rigidity is small.

The passage of fluid vesicles through narrow pores has some relevance to medical/pharmaceutical applications. In Monte Carlo simulations it is shown that a spontaneous transport of vesicles can be induced by a concentration gradient of osmotically active particles which corresponds to the physiological conditions. The necessary osmotic conditions and the charateristic time scales are calculated. For real experiments, penetration into the pore should occur within a few minutes. Moreover, it was observed that vesicles with a homogeneous positive spontaneous curvature can be deformed more easily into prolate shapes than vesicles with zero spontaneous curvature. This effect leads to a decrease of the energy barrier for the penetration into a wide pore, which has a radius slightly smaller than that of the vesicle.

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13

Lee, David C. (David Chunyi) 1978. "Simulating Turbo codes using a modular simulation platform." Thesis, Massachusetts Institute of Technology, 2002. http://hdl.handle.net/1721.1/87259.

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14

Huang, Ya-Lin. "Ad hoc distributed simulation: a method for embedded online simulations." Diss., Georgia Institute of Technology, 2013. http://hdl.handle.net/1853/49060.

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The continual growth of computing power in small devices has motivated the development of novel approaches to optimizing operational systems efficiently and effectively. These optimization problems are often so complex that solving them analytically may be difficult, if not prohibited. One method for solving such problems is to use online simulation. However, challenges in using online simulation include the issues of responsiveness (e.g., because of communication delays), scalability, and failure resistance. To tackle these issues, this study proposes embedding online simulations into a network of sensors that monitors the system under investigation. This thesis explores an approach termed “ad hoc distributed simulation,” which is based on embedding online simulations into a sensor network and adding communication and synchronization among simulators to model operational systems. This approach offers several potential advantages over existing approaches: (1) it can provide rapid response to system dynamics as well as efficiency since data exchange is local to the sensor network, (2) it can achieve better scalability to incorporate more sensors, and (3) it can provide better robustness to failures because portions of the system are still under local control. This research addresses several statistical issues in this ad hoc approach: (1) rapid and effective estimation of the input processes at model boundaries, (2) estimation of system-wide performance measures from individual simulator outputs, and (3) correction mechanisms responding to unexpected events or inaccuracies within the model. This thesis examines ad hoc distributed simulation analytically and experimentally, mainly focusing on the accuracy of predicting the performance of open queueing networks. First, the analytical part formalizes the ad hoc approach and evaluates its accuracy at modeling certain class of open queueing networks with regard to the steady-state system performance measures. This work concerning steady-state metrics is extended to a broader class of networks by an empirical study, which presents evidence to show that the ad hoc approach can generate predictions comparable to those from sequential simulations. Furthermore, a “buffered-area” mechanism is proposed to substantially reduce prediction bias with a moderate increase in execution time. In addition to those steady-state studies, another empirical study targets the prediction accuracy of the ad hoc approach at open queueing networks with short-term system-state transients. This study demonstrates that, with slight modification to the prior design of the ad hoc queueing simulation method for those steady-state studies, system dynamics can be well modeled. The results, again, support the conclusion that the ad hoc approach is competitive to the sequential simulation method in terms of prediction accuracy.

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Singh, Harpreet. "Computer simulations of realistic microstructures implications for simulation-based materials design/." Diss., Atlanta, Ga. : Georgia Institute of Technology, 2007. http://hdl.handle.net/1853/22564.

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Thesis (Ph. D.)--Materials Science and Engineering, Georgia Institute of Technology, 2008.
Committee Chair: Dr. Arun Gokhale; Committee Member: Dr. Hamid Garmestani; Committee Member: Dr. Karl Jacob; Committee Member: Dr. Meilin Liu; Committee Member: Dr. Steve Johnson.

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Andersson, Håkan. "Parallel Simulation : Parallel computing for high performance LTE radio network simulations." Thesis, Mittuniversitetet, Institutionen för informationsteknologi och medier, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:miun:diva-12390.

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Radio access technologies for cellular mobile networks are continuously being evolved to meet the future demands for higher data rates, and lower end‐to‐end delays. In the research and development of LTE, radio network simulations play an essential role. The evolution of parallel processing hardware makes it desirable to exploit the potential gains of parallelizing LTE radio network simulations using multithreading techniques in contrast to distributing experiments over processors as independent simulation job processes. There is a hypothesis that parallel speedup gain diminishes when running many parallel simulation jobs concurrently on the same machine due to the increased memory requirements. A proposed multithreaded prototype of the Ericsson LTE simulator has been constructed, encapsulating scheduling, execution and synchronization of asynchronous physical layer computations. In order to provide implementation transparency, an algorithm has been proposed to sort and synchronize log events enabling a sequential logging model on top of non‐deterministic execution. In order to evaluate and compare multithreading techniques to parallel simulation job distribution, a large number of experiments have been carried out for four very diverse simulation scenarios. The evaluation of the results from these experiments involved analysis of average measured execution times and comparison with ideal estimates derived from Amdahl’s law in order to analyze overhead. It has been shown that the proposed multithreaded task‐oriented framework provides a convenient way to execute LTE physical layer models asynchronously on multi‐core processors, still providing deterministic results that are equivalent to the results of a sequential simulator. However, it has been indicated that distributing parallel independent jobs over processors is currently more efficient than multithreading techniques, even though the achieved speedup is far from ideal. This conclusion is based on the observation that the overhead caused by increased memory requirements, memory access and system bus congestion is currently smaller than the thread management and synchronization overhead of the proposed multithreaded Java prototype.

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Acél, Peter Paul Acél Peter Paul Acél Peter Paul Acél Peter Paul. "Methode zur Durchführung betrieblicher Simulationen : effiziente Optimierung der diskreten Simulation /." [S.l.] : [s.n.], 1996. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=11459.

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Buchta, Christian, and Sara Dolnicar. "Learning by simulation. Computer simulations for strategic marketing decision support in tourism." SFB Adaptive Information Systems and Modelling in Economics and Management Science, WU Vienna University of Economics and Business, 2003. http://epub.wu.ac.at/1718/1/document.pdf.

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This paper describes the use of corporate decision and strategy simulations as a decision-support instrument under varying market conditions in the tourism industry. It goes on to illustrate this use of simulations with an experiment which investigates how successful different market segmentation approaches are in destination management. The experiment assumes a competitive environment and various cycle-length conditions with regard to budget and strategic planning. Computer simulations prove to be a useful management tool, allowing customized experiments which provide insight into the functioning of the market and therefore represent an interesting tool for managerial decision support. The main drawback is the initial setup of a customized computer simulation, which is time-consuming and involves defining parameters with great care in order to represent the actual market environment and to avoid excessive complexity in testing cause-effect-relationships. (author's abstract)
Series: Report Series SFB "Adaptive Information Systems and Modelling in Economics and Management Science"

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Celik, Nurcin. "INTEGRATED DECISION MAKING FOR PLANNING AND CONTROL OF DISTRIBUTED MANUFACTURING ENTERPRISES USING DYNAMIC-DATA-DRIVEN ADAPTIVE MULTI-SCALE SIMULATIONS (DDDAMS)." Diss., The University of Arizona, 2010. http://hdl.handle.net/10150/195427.

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Discrete-event simulation has become one of the most widely used analysis tools for large-scale, complex and dynamic systems such as supply chains as it can take randomness into account and address very detailed models. However, there are major challenges that are faced in simulating such systems, especially when they are used to support short-term decisions (e.g., operational decisions or maintenance and scheduling decisions considered in this research). First, a detailed simulation requires significant amounts of computation time. Second, given the enormous amount of dynamically-changing data that exists in the system, information needs to be updated wisely in the model in order to prevent unnecessary usage of computing and networking resources. Third, there is a lack of methods allowing dynamic data updates during the simulation execution. Overall, in a simulation-based planning and control framework, timely monitoring, analysis, and control is important not to disrupt a dynamically changing system. To meet this temporal requirement and address the above mentioned challenges, a Dynamic-Data-Driven Adaptive Multi-Scale Simulation (DDDAMS) paradigm is proposed to adaptively adjust the fidelity of a simulation model against available computational resources by incorporating dynamic data into the executing model, which then steers the measurement process for selective data update. To the best of our knowledge, the proposed DDDAMS methodology is one of the first efforts to present a coherent integrated decision making framework for timely planning and control of distributed manufacturing enterprises.To this end, comprehensive system architecture and methodologies are first proposed, where the components include 1) real time DDDAM-Simulation, 2) grid computing modules, 3) Web Service communication server, 4) database, 5) various sensors, and 6) real system. Four algorithms are then developed and embedded into a real-time simulator for enabling its DDDAMS capabilities such as abnormality detection, fidelity selection, fidelity assignment, and prediction and task generation. As part of the developed algorithms, improvements are made to the resampling techniques for sequential Bayesian inferencing, and their performance is benchmarked in terms of their resampling qualities and computational efficiencies. Grid computing and Web Services are used for computational resources management and inter-operable communications among distributed software components, respectively. A prototype of proposed DDDAM-Simulation was successfully implemented for preventive maintenance scheduling and part routing scheduling in a semiconductor manufacturing supply chain, where the results look quite promising.

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Meleady, Rose. "Simulating social dilemmas : promoting cooperative behaviour through strategies of mental simulation." Thesis, University of Kent, 2013. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.633829.

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One of the most consistent findings in experimental social dilemmas research is the positive effect group discussion has on cooperative behaviour. At a time when cooperation is critical to tackle societal problems, ranging from debt to deforestation, understanding the dynamics of group discussion is a pressing need. Unfortunately, research investigating the processes underlying the effect has stalled in a state of disagreement, whilst applications have been discouraged by the realisation that discussion amongst all decision-makers is often difficult to establish. The first part of this thesis uniquely integrates previously competing 'single-cause' explanations of the group discussion effect into a single process model of group discussion, providing a more complete theoretical picture of how intenelated factors combine to facilitate discussion induced cooperation. On the basis of this theoretical analysis, complimentary approaches to the indirect and feasible implementation of group discussion are proposed, including the entirely new concept of imagined group discussion. Results within the second part of the thesis support the conclusion that when individuals imagine discussing a social dilemma with nominal group members they engage in cognitive processes consonant with those underlying the direct group discussion effect, thereby resulting in higher levels of cooperative behaviour. The third part of the thesis demonstrates that when the size of the group facing the dilemma is so large that even imagining a discussion amongst all decision-makers becomes impracticable (i.e. within global-level dilemmas), an imagined discussion with a single outgroup member successfully encourages collectively beneficial decision-making. The use of imagined communication techniques is therefore advocated as a simple, versatile and inexpensive means of encouraging cooperative behaviour without the limiting requirement of proximity between discussants.

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Spruegel, Tobias C., and Sandro Wartzack. "Das FEA-Assistenzsystem – Analyseteil FEdelM." Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-215130.

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Die simulative Absicherung von Produkten in den frühen Phasen der Produktentwicklung wird immer wichtiger, um den Anforderungen nach steigender Effizienz gerecht zu werden. Da das Angebot an erfahrenen Berechnungsingenieuren mit langjähriger Berufserfahrung begrenzt ist gilt es weniger erfahrene Simulationsanwender bei der Durchführung von aussagekräftigen Finite-Elemente-Simulationen zu unterstützen. Die Autoren stellen im Rahmen des Beitrags das Konzept des Analyseteils FEdelM eines FEA-Assistenzsystems vor, welches strukturmechanische Finite-Elemente (FE) Simulationen auf Plausibilität überprüft und auftretende Fehler möglichst automatisiert zu erkennt und behebt. Hierbei werden die einzelnen Module und deren Verknüpfungen untereinander und zu anderen Anwendungen vorgestellt.

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22

Guesnet, Étienne. "Modélisation du comportement mécanique et thermique des silices nano-architecturées." Thesis, Université Grenoble Alpes (ComUE), 2018. http://www.theses.fr/2018GREAI075/document.

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Les silices nanostructurées sont des matériaux ultra-poreux (plus de 80% de porosité) utilisés pour la confection de Panneaux Isolants sous Vides (PIV). Elles possèdent des propriétés thermiques exceptionnelles, mais de piètres propriétés mécaniques.L’enjeu de cette thèse est d’étudier ces matériaux aux échelles de la particule (quelques nm), de l’agrégat de particules (quelques dizaines de nm) et de l’agglomérat d’agrégats (quelques centaines de nm), afin de mieux comprendre les comportements mécanique et thermique à l’aide de simulations, et de proposer des pistes pour améliorer le compromis thermique / mécanique. La nature particulaire du matériau et son caractère multi-échelle justifient l’utilisation de méthodes de simulations discrètes (DEM : Discrete Element Method). Un modèle original permettant de générer des agrégats à morphologiecontrôlée (dimension fractale, rayon de giration, porosité) est proposé. Le comportement à la compaction des agrégats est ensuite étudié par simulations DEM. Une approche par cyclage à faible densité a été développée pour obtenir des arrangements initiaux réalistes d’agrégats. La prépondérance des phénomènes adhésifs dans le système rend en effet celui-ci très sensible à l’arrangement initial. La réponse en traction des structures générées par compaction est également évaluée.L’influence de la morphologie des agrégats, de l’adhésion et du frottement ont été étudiées. L’accent est mis sur la comparaison de deux types de silices (pyrogénées et précipitées) présentant des morphologies différentes et pour lesquelles des données expérimentales permettent une confrontation avec les simulations. Les simulations présentées permettent d’apporter des réponses sur l’origine des différences de comportement mécanique observées expérimentalement pour ces deux types de silice.Une modélisation de la conductivité thermique du matériau, avec une focalisation sur la conductivité solide, est également proposée
Nanostructured silicas are ultra-porous materials (more than 80 % porosity) used to make Vacuum Insulation Panels (VIP).They have exceptional thermal properties, but poor mechanical properties. The goal of this thesis is to study these materials at the scale of the particle (a few nm), the aggregate of particles (a few tens of nm) and the agglomerate of aggregates (a few hundred nm), in order to better understand mechanical and thermal behaviour using simulations, and to propose ways to improve the thermal / mechanical compromise. The particulate nature of the material and its multi-scale naturejustify the use of Discrete Element Methods (DEM). An original model allowing to generate aggregates with controlledmorphology (fractal dimension, radius of gyration, porosity) is proposed. The compaction behaviour of the aggregates is then studied by DEM. A low-density cycling approach has been developed to obtain realistic initial aggregate arrangements.The preponderance of adhesive phenomena in the system makes it very sensitive to the initial arrangement. The tensile response of structures generated by compaction is also evaluated. The influence of aggregate morphology, adhesion and friction were studied. Emphasis is placed on the comparison of two types of silica (pyrogenic and precipitated) with different morphologies and for which experimental data allow a comparison with simulations. The simulations presented allow us to provide answers on the origin of the differences in mechanical behaviour observed experimentally for these two types of silica.A modeling of the thermal conductivity of the material, with a focus on solid conductivity, is also proposed

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23

Leveugle, Benoît. "Simulation DNS de l’interaction flamme-paroi dans les moteurs à allumage commandé." Thesis, Rouen, INSA, 2012. http://www.theses.fr/2012ISAM0021/document.

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Dans le cadre du projet INTERMARC (INTERaction dans les Moteurs à Allumage Commandé), la tâche du CORIA a consisté à produire une base de données à l'échelle RANS (provenant de données DNS) afin de tester, valider et modifier le modèle d'interaction développée par IFPen. Ce modèle vise l'ajout d'une composante d'interaction, phénomène non pris en compte par les lois de paroi actuelles.Ce projet repose sur l'interaction forte entre les différents protagonistes présents. Le CORIA et le CETHIL ont travaillé ensemble à la réalisation d'une base de données pour tester les modèles initiaux proposés par IFPen, puis en fonction des résultats obtenus, à itérer avec IFPen pour modifier et améliorer les modèles. Ces tests ont inclus des simulations 2D laminaires, 2D turbulentes, et 3D turbulentes
Under the INTERMARC project (Flame wall interaction in spark ignition engines), CORIA's job was to produce a database to RANS scale (from DNS data) to test, validate and modify the interaction model developed by IFPEN. This model aims the addition of the interaction phenomena, non-captured by the current wall laws. This project is based on the strong interaction between the different actors. The CORIA and the CETHIL have worked together in the creation of the database, where the experimental data were also used to validate the resuslts of the DNS code.CORIA then used this database to test the original model proposed by IFPPEN, then according to the results obtained, CORIA iterated with IFPEN to modify and improve the models. These tests included laminar 2D simulations, 2D turbulent and 3D turbulent simulations

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24

Falcigno, Steven V. "The Simulation Engine, a platform for developing industrial process knowledge-based discrete event simulations." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape16/PQDD_0009/MQ33370.pdf.

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25

Balasubramanian, Sivaramakrishnan. "A Novel Approach for the Direct Simulation of Subgrid-Scale Physics in Fire Simulations." NCSU, 2010. http://www.lib.ncsu.edu/theses/available/etd-12212009-122246/.

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A Lagrangian framework for computing subgrid-scale combustion physics in Large Eddy Simulations (LES) of fire is formulated and validated. The framework is based on coupling LES formulation, based on the Fire Dynamic Simulator (FDS) with the One-Dimensional Turbulence (ODT) model. The ODT model involves reaction-diffusion and turbulent transport along one-dimensional domains. The one-dimensional domains are attached to the flame brush positions, computed in LES, and are allowed to propagate along its surface. The Lagrangian LES-ODT framework involves various implementations including a) momentum, energy, and species solution along one-dimensional ODT domain, b) Tracking of ODT domains through their anchor points, c) Filtering of ODT solutions on the LES grid, d) Inverse filtering (interpolation) of LES velocity fields in ODT domains, and e) The management of ODT domains at the flow inlets and as they reach the flame tip. Comparison of LES-ODT solutions with FDS solutions shows that the LES-ODT implementation reproduces reasonably well the flame topology and structure.

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Pawlik, Amadeusz, and Henry Andersson. "Visualising Interval-Based Simulations." Thesis, Högskolan i Halmstad, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-28592.

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Acumen is a language and tool for modeling and simulating cyber-physical systems. It allows the user to conduct simulations using a technique called rigorous simulation that produces results with explicit error bounds, expressed as intervals. This feature can be useful when designing and testing systems where the reliability of results or taking uncertainty into account is important. Unfortunately, analyzing these simulation results can be difficult, as Acumen supports only two ways of presenting them: raw data tables and 2D-plots. These views of the data make certain kinds of analysis cumbersome, such as understanding correlations between variables. This is especially true when the model in question is large. This project proposes a new way of visualising rigorous simulation results in Acumen. The goal of this project is to create a method for visualising intervallic values in 3D, and implement it in Acumen. To achieve that, every span of values is represented as a series of overlapping objects. This family of objects, which constitutes an under-approximation of the true simulation result, is then wrapped inside a semi-translucent box that is a conservative over-approximation of the simulation result. The resulting implementation makes for a combination of mathematical correctness (rigour), and mediation of intervals in question. It enables the user to explore the results of his rigorous simulations as conveniently as with the existing, non-rigorous simulation methods, using the 3D visualisation to simplify the study of real-life problems. To our knowledge, no existing software features visualisation of interval-based simulation results, nor is there any convention for doing this. Some ways in which the proposed solution could be improved are suggested at the end of this report

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27

Helal, Magdy. "A hybrid system dynamics-discrete event simulation approach to simulating the manufacturing enterprise." Orlando, Fla. : University of Central Florida, 2008. http://purl.fcla.edu/fcla/etd/CFE0002264.

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28

Kernstine, Kemp H. "Design space exploration of stochastic system-of-systems simulations using adaptive sequential experiments." Diss., Georgia Institute of Technology, 2012. http://hdl.handle.net/1853/44799.

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The complexities of our surrounding environments are becoming increasingly diverse, more integrated, and continuously more difficult to predict and characterize. These modeling complexities are ever more prevalent in System-of-Systems (SoS) simulations where computational times can surpass real-time and are often dictated by stochastic processes and non-continuous emergent behaviors. As the number of connections continue to increase in modeling environments and the number of external noise variables continue to multiply, these SoS simulations can no longer be explored with traditional means without significantly wasting computational resources. This research develops and tests an adaptive sequential design of experiments to reduce the computational expense of exploring these complex design spaces. Prior to developing the algorithm, the defining statistical attributes of these spaces are researched and identified. Following this identification, various techniques capable of capturing these features are compared and an algorithm is synthesized. The final algorithm will be shown to improve the exploration of stochastic simulations over existing methods by increasing the global accuracy and computational speed, while reducing the number of simulations required to learn these spaces.

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Chmura, Thorsten. "Analyse, Modellierung und Simulationen von Routenwahlverhalten / Analyses, Modelling and Simulation of Route Choice Behaviour." Gerhard-Mercator-Universitaet Duisburg, 2005. http://www.ub.uni-duisburg.de/ETD-db/theses/available/duett-05152005-222337/.

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This thesis will give an overview about the connection of physics and economy in special view of human behavior in traffic scenarios. Main topic is the human decision making process in a two-route-choice scenario. In three main Experiments, human players had to decide between two routes which connect two cities. The first experiment is defined by a pure Nash-equilibrium and 18 participants, the second experiment is similar, but alternating construction sites on both routes were added. Experiment 1 and 2 are played over 200 periods. The third experiment is a minority game with mixed equilibria and 9 participants. Experiment 3 was played over 100 periods. Furthermore the first experiment was extended to a larger group of players up to 90 persons. For every experiment two treatments with 6 observations were played. The treatments differ in the given information to the participants before they choose between the two routes. In the first treatment the information about the own travel time was given, additionally in the second treatment the information about travel times on both routes were given. The second part of the thesis describes the statistical data and illustrates the results. Two main results are that the equilibrium was not stable in the experiments, the fluctuations persists to the end of every observation. Further on two player types were found and explained in this chapter. In the third part of this thesis an extended payoff-sum model is described and explained. Simulations using this reinforcement learning model were run and show the reproducibility of the empirical data. In the conclusions the main results are shown and discussed.

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Richart, Nicolas. "Conception et mise en oeuvre d'une plate-forme de pilotage de simltions numériques parallèles et distribuées." Thesis, Bordeaux 1, 2010. http://www.theses.fr/2010BOR13991/document.

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Le domaine de la simulation numérique évolue vers des simulations de phénomènes physiques toujours plus complexes. Cela se traduit typiquement par le couplage de plusieurs codes de simulation, où chaque code va gérer une physique (simulations multi-physiques) ou une échelle particulière (simulations multi-échelles). Dans ce cadre, l'analyse des résultats des simulations est un point clé, que ce soit en phase de développement pour valider les codes ou détecter des erreurs, ou en phase de production pour confronter les résultats à la réalité expérimentale. Dans tous les cas, le pilotage de simulations peut aider durant ce processus d'analyse des résultats. L'objectif de cette thèse est de concevoir et de réaliser une plate-forme logicielle permettant de piloter de telles simulations. Plus précisément, il s'agit à partir d'un client de pilotage distant d'accéder ou de modifier les données de la simulation de manière cohérente, afin par exemple de visualiser "en-ligne" les résultats intermédiaires. Pour ce faire, nous avons proposé un modèle de pilotage permettant de représenter des simulations couplées et d'interagir avec elles efficacement et de manière cohérente. Ces travaux ont été validés sur une simulation multi-échelles en physique des matériaux
The numerical simulations evolve more and more to simulations of complex physical phenomena through multi-scale or multi-physics codes. For these kind of simulations data analysis is a main issue for many reasons, as detecting bugs during the development phase or to understand the dynamic of the physical phenomena simulated during the production phase. The computational steering is a technique well suited to do all this kind of data analysis. The goal of this thesis is to design and develop a computational steering framework that take into account the complexity of coupled simulations. So, through a computational steering client we want to interact coherently with data generated in coupled simulations. This afford for example to visualize on-line the intermediate results of simulations. In order to make this possible we will introduce an abstract model that enables to represent coupled simulations and to know when we can interact coherently with them. These works have been validated on a legacy multi-scale simulation of material physics

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Dallaire, Jonathan. "Thermal conductivity of carbon nanotubes from equilibrium molecular dynamics simulations : sensitivity to modeling and simulation parameters." Thesis, Université Laval, 2012. http://www.theses.ulaval.ca/2012/29017/29017.pdf.

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Ozkan, Baris Egemen. "Autonomous agent-based simulation of a model simulating the human air-threat assessment process." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2004. http://library.nps.navy.mil/uhtbin/hyperion/04Mar%5FOzkan.pdf.

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Campos, André. "Une architecture logicielle pour le developpement de simulations visuelles et interactives individu-centrees : application a la simulation d'ecosystemes et a la simulation sur le web." Clermont-Ferrand 2, 2000. http://www.theses.fr/2000CLF22221.

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L'objectif de ce manuscrit est de proposer l'integration d'un ensemble d'outils de conception utiles au developpement de logiciels de simulation d'ecosystemes. Les domaines de recherche abordes traitent de la reutilisation logicielle, des frameworks orientes objet et patrons de conception, des aspects de simulation visuelle interactive, ainsi que des aspects interactifs du web. Les simulateurs d'ecosystemes auxquels nous nous limitons sont bases sur une approche individu centree. Nous utilisons donc le paradigme multi-agent pour mettre en place des telles simulations, notamment pour mettre en uvre des comportements sociaux. L'aspect innovateur de ce travail est la presentation d'un framework permettant l'utilisation et la reutilisation de structures logicielles pour faciliter 1) la comprehension d'un moteur de simulation d'ecosysteme qui gere des aspects visuels et interactifs dans une approche individu centree ; et 2) le developpement de nouvelles simulations avec de telles caracteristiques. Nous avons developpe plusieurs applications concretes pour valider le framework. Parmi elles, nous pretons speciale attention a la plateforme da vinci. Cette plateforme permet la creation d'un environnement artificiel simple compose d'une societe d'agents afin de faciliter la conception de simulations qui prennent en compte les caracteristiques de l'environnement des insects sociaux, comme les fourmis et les termites.

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Lucario, Thomas. "The Use of PC Based Simulation Systems in the Training of Army Infantry Officers - An Evaluation of the Rapid Decision Trainer." Master's thesis, University of Central Florida, 2006. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/3884.

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This research considers two modes of training Army infantry officers in initial training to conduct a platoon live fire exercise. Leaders from groups that were training with the current classroom training methods were compared to leaders from groups whose training was augmented with a PC based training system known as the Rapid Decision Trainer (RDT). The RDT was developed by the US Army Research Development and Engineering Command for the purpose of aiding in the training of tactical decision making and troop leading procedures of officers in the initial levels of training to become rifle platoon leaders. The RDT allows the leader in training to run through platoon level operations prior to live execution in a simulated combat environment. The focus of the system is on leadership tasks and decision making in areas such as unit movement, internal unit communication and contingency planning, and other dismounted infantry operations. Over the past year, some Infantry Officer Basic Course platoons at Ft. Benning have used the RDT in an experimental manner. Anecdotal evidence suggests that the system is beneficial in training IOBC officers. The Army Research Institute (ARI) conducted a preliminary evaluation of the RDT in March 2005 (Beal 2005). However, no quantitative measures were used in the evaluation of the RDT, only subjective evaluations of the users. Additionally, there were no formal evaluations by the training cadre, only the users themselves. This experiment continues the work of ARI and uses qualitative and quantitative data from both users and the evaluating cadre. In this experiment, the effectiveness of the RDT was evaluated through measuring leader behaviors and personal preferences. Three measurement approaches were used; (1) quantitative performance measures of leader actions, (2) qualitative situational awareness and evaluations of inclusion in the non leader players, and (3) a qualitative evaluation of the system's usability and effectiveness by system users. Analysis reveals statistically significant findings that challenge the current norms.
M.S.
Department of Industrial Engineering and Management Systems
Engineering and Computer Science
Industrial Engineering and Management Systems

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Boyd, Edward L., Charles S. Novits, and Robert A. Boisvert. "Distributed Interactive Simulation (DIS): An Overview Of The System And Its Potential Uses." International Foundation for Telemetering, 1994. http://hdl.handle.net/10150/608576.

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International Telemetering Conference Proceedings / October 17-20, 1994 / Town & Country Hotel and Conference Center, San Diego, California
The Distributed Interactive Simulation (DIS) concept, since its inception, has been defined into three separate but distinct areas of service. • Viewing of data in the real-time environment. • Multiple range viewing and usage of"real-time data." • Problems with the sharing of information through DIS. This paper will discuss the DIS concept and some of the various methods available to display this data to users of the system.

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Ó, Duibhir Conall. "Simulating Systems : Interactive computer simulations as an educational tool for teaching about social-ecological systems." Thesis, Linnéuniversitetet, Institutionen för kulturvetenskaper (KV), 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-105265.

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This study adopts an experimental design to examine the use, in practice, of interactive computer simulations as educational tools. With the accelerated use of digital learning and the urgency of implementing sustainable development, the important role of interactive computer simulations is examined. While rooted in the digital humanities, the study focuses on ecopedagogy as a theoretical lens by which to assess critical learning. Drawing on previous research, ‘Shiny’ was used to develop a simple, interactive application consisting of a tool where users can calculate the cost and carbon emissions of energy production within a specific system. This application was used as part of a participatory experiment with 47 participants, and the data returned was analysed to examine its educational merit. The findings of the study indicate positive engagement with the simulation tool used, along with important lessons for further study.

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Balmont, Mickael. "Fiabilité des composants enfouis dans les circuits imprimés." Thesis, Bordeaux, 2019. http://www.theses.fr/2019BORD0229/document.

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Le désir de miniaturisation des circuits électroniques a mené l’électronique à développer de nouvelles méthodes d’assemblage. Les progrès réalisés passent par la complexification des fonctions, le développement de nouvelles interconnexions liant le circuit au composant ou par les choix d’architecture, une optimisation du volume. Après avoir repoussé les limites d’optimisation avec les assemblages en trois dimensions, la technologie s’est tournée vers un volume présent dans toutes les cartes électroniques mais qui ne joue aucun rôle actif dans celui-ci : le support des fonctions, le PCB. La solution apportée est l’enfouissement de composant dans ce volume. Les premiers bénéfices de cette solution apparaissent rapidement : gain de volume et protection des composants, c’est pourquoi elle se développe rapidement dans l’industrie.Partant de ce postulat, Valeo souhaite adapter cette technologie pour réduire la taille d’une caméra de recul dédiée à l’automobile. Les exigences du domaine automobile étant plus strictes que dans d’autres industries, l’investigation plus poussée de la technologie d’enfouissement est nécessaire. L’objectif est de valider la fiabilité et la robustesse du circuit selon une méthode de fabrication. Ainsi, l’IMS de Bordeaux intègre le projet EDDEMA pour apporter une expertise, via des simulations thermomécaniques par éléments finis, sur la conception du circuit.Dans le cadre de cette thèse et pour répondre aux attentes du projet, deux axes d’études sont suivis. Une méthodologie généraliste est proposée pour parvenir à définir les interconnexions jugées les plus fragiles dans le cadre de l’emploi de la technologie d’enfouissement et justifier l’utilisation des simulations par éléments finis selon les exigences attendues. L’objectif est de déterminer la durée de vie d’une interconnexion liant le composant au circuit en fonction de sa nature (brasure, via,…) et des caractéristiques du composant et du circuit (dimensions, hauteur,…) et valider les choix technologiques tels que les matériaux ou les techniques faits dès la fabrication. Cette étude s’inscrit dans une recherche locale autour du composant. La seconde étude se recentre sur le circuit développé dans le cadre du projet. Il sera étudié l’impact de la position des composants actifs enfouis dans le PCB sur le circuit (déformation, contraintes) et la représentation des composants passifs dans cette structure pour définir, selon les considérations thermomécaniques, les limites de positionnement dans la conception du circuit. Affiner le modèle passera par des mesures réalisées sur les premiers prototypes pour corroborer les simulations réalisées.Tout ceci mène à déterminer les avantages sur la technologie d’enfouissement et le gain apporté en terme de fiabilité et de robustesse du circuit et des composants et valider son utilisation dans le secteur automobile
The desire for miniaturization of electronic circuits led the electronics to develop new methods of assembly. Progress is made through the complexification of functions, the development of new interconnections linking the circuit to the component or by the choice of architecture, an optimization of the volume. After pushing the limits of optimization with the three-dimensional assemblies, the technology turned to a volume present in all the electronic cards but which plays no active part in this one: the support of the functions, the PCB. The solution provided is to embed component in this volume. The first benefits of this solution appear quickly: volume gain and protection of components, which is why it is developing rapidly in the industry.Based on this premise, Valeo wants to adapt this technology to reduce the size of a rearview camera dedicated to the automobile. As automotive requirements are stricter than in other industries, further investigation of embedded technology is required. The objective is to validate the reliability and robustness of the circuit according to a manufacturing method. Thus, the IMS Bordeaux integrates the EDDEMA project to provide expertise, via finite element thermomechanical simulations, on the design of the circuit.As part of this thesis and to meet the expectations of the project, two studies are investigated. A general methodology is proposed to define the interconnections considered the most fragile in the context of the use of embedded technology and justify the use of finite element simulations according to the expected requirements. The objective is to determine the lifetime of an interconnection linking the component to the circuit according to its nature (solder, via, ...) and the characteristics of the component and the circuit (dimensions, height, ...) and validate the choices. such as materials or techniques made from the time of manufacture. This study is part of a local search around the component. The second study focuses on the circuit developed in the project. The impact of the position of the active components embedded in the PCB on the circuit (deformation, constraints) and the representation of the passive components in this structure will be studied to define, according to the thermomechanical considerations, the positioning limits in the circuit design. . To refine the model will pass by measurements realized on the first prototypes to corroborate the realized simulations.All this leads to determining the advantages on the embedded technology and the gain in terms of reliability and robustness of the circuit and components and validating its use in the automotive sector

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Richart, Nicolas. "Conception et mise en oeuvre d'une plate-forme de pilotage de simulations numériques parallèles et distribuées." Phd thesis, Université Sciences et Technologies - Bordeaux I, 2010. http://tel.archives-ouvertes.fr/tel-00464406.

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Le domaine de la simulation numérique évolue vers des simulations de phénomènes physiques toujours plus complexes. Cela se traduit typiquement par le couplage de plusieurs codes de simulation, où chaque code va gérer une physique (simulations multi-physiques) ou une échelle particulière (simulations multi-échelles). Dans ce cadre, l'analyse des résultats des simulations est un point clé, que ce soit en phase de développement pour valider les codes ou détecter des erreurs, ou en phase de production pour confronter les résultats à la réalité expérimentale. Dans tous les cas, le pilotage de simulations peut aider durant ce processus d'analyse des résultats. L'objectif de cette thèse est de concevoir et de réaliser une plate-forme logicielle permettant de piloter de telles simulations. Plus précisément, il s'agit à partir d'un client de pilotage distant d'accéder ou de modifier les données de la simulation de manière cohérente, afin par exemple de visualiser "en-ligne" les résultats intermédiaires. Pour ce faire, nous avons proposé un modèle de pilotage permettant de représenter des simulations couplées et d'interagir avec elles efficacement et de manière cohérente. Ces travaux ont été validés sur une simulation multi-échelles en physique des matériaux.

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Naumann, Steve E. (Steve Eugene). "Computer Simulation Placements in a Unit of Instruction." Thesis, University of North Texas, 1994. https://digital.library.unt.edu/ark:/67531/metadc278685/.

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Educators considering implementing a computer simulation must decide on the optimum placement of the simulation in the unit of instruction to maximize student learning. This study examined student achievement using two different placements for the computer simulation, The Civil War, in a unit of instruction of 8th grade American History students in a suburban middle school.

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Häll, Lars O. "Developing educational computer-assisted simulations : Exploring a new approach to researching learning in collaborative health care simulation contexts." Doctoral thesis, Umeå universitet, Pedagogiska institutionen, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-64296.

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Health care education is developing and simulations, in different guises, are gaining increasing attention as a means of overcoming tensions between instructional models and educational objectives. The role of simulations is, however, yet to be fully defined and will be dependent on the actual impact simulations on educational practice. Research need to better understand this impact and contribute to developing simulation practices. There is, therefore, a strong need for research that can balance scientific stringency and practical utility. This presents a challenge in a field that is biased in favor of laboratory experiments where theoretical accounts are also rare. This thesis explores a new theoretical and methodological approach, as a means of meeting this challenge. It draws upon Rose Luckin's Ecology of Resources framework for redesigning learning contexts (2010) and it attempts to explore relations between learning context, learner interactions, and learning outcomes, in order to identify opportunities for the development of educational simulation practice. In researching different types of health care simulations in their own right, arguments have been made that it is necessary to strive for smaller and more useful generalizations. In response to this challenge, this thesis delineates one type of simulation context: collaborative educational computer-assisted simulation (ECAS) in health care education. After reviewing previous research on related topics, a model of this type of context has been developed. Based on this general model, the particular subfield of collaborative radiology in ECAS has been analyzed and researched. Four articles on this topic present empirical contributions that address different relations between context, learner interactions, and learning outcomes in collaborative radiology in ECAS. The first one explores how moving from a static tool to an ECAS changes what learners talk about, how they talk about it, and how they develop during training. The second one explores in more detail relations between the features of ECAS, the content of learner interactions, and the impact on learning. The third one explores how context design impacts peer interaction, and the fourth compares more and less successful groups in order to identify needs and opportunities for development of the learning context. The empirical data are used to discuss relations between learning context, learner interactions, and learning outcomes, and how collaborative scripts may be potentially useful in the development of collaborative ECAS in health care education. Such scripts could support for instance explicit dialogue about relations between context-dependent doing and subject-specific principles, thorough engagement with simulation feedback and inclusion of all simulations participants. A new path for health care simulation research is suggested, including a move beyond laboratory experiments towards dealing with the messiness of actual educational practice, a move beyond universal generalizations towards smaller-scale context considerate and more practically useful generalizations.
Learning Radiology in Simulated Environments

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Tasche, Jos. "Theory and simulation of solubility and partitioning in polymers : application of SAFT-γ Mie and molecular dynamics simulations." Thesis, Durham University, 2018. http://etheses.dur.ac.uk/12672/.

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Theory, simulation and experiment were used in this work to study the solubility and partitioning in polymer systems. The recently published SAFT-γ Mie equation of state was implemented into a stand-alone program together with all algorithms for parametrising new models and predicting phase equilibria. An analysis of the transferability of low-molecular weight Mie potential parameters for predicting the miscibility of polymer mixtures and partitioning of oligomers in polymer systems revealed the need for new models optimised for polymers. A systematic overview and analysis of available and typical experimental polymer data concluded that pure component polymer melt densities and cloud point temperatures (liquid–liquid equilibria) are the best and most practical choice for parametrising new SAFT-γ Mie models. New polymer models were developed for a range of pure polymers, several binary mixtures and one ternary polymer mixture. All models showed very good agreement with the experimental data included in the model development. Good agreement was found for predicted properties and conditions not included in the parametrising process. Coarse-grained (CG) force fields were developed with the help of the SAFT-γ Mie equation of state. Excellent agreement was found for the direct translation of Mie potentials to CG force fields for modelling properties of low-molecular weight compounds and densities of polymer melts. Coarse-grained models for molecular dynamics (MD) simulations of polymer phase equilibria are more challenging to develop due to greater computational resource requirements and less perfect agreement between SAFT-γ Mie and MD force fields. The challenges were demonstrated and discussed for a polystyrene solution and a binary mixture of polystyrene and polyisoprene. The synergistic power of SAFT-γ Mie and MD simulations was used for developing coarse grained models for describing the surface of a oligomer/polymer blend. Pure component parameters were optimised within SAFT-γ Mie. The SAFT-γ Mie CG model reproduced experimental partial density surface profiles as a function of blend composition without the need to rescale length scales. Oligomer surface enrichment, wetting transition and wetting layers were correctly predicted with a single model.

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Chen, Jingzhi. "Molecular dynamics simulation of the self-assembly of icosahedral virus." Thesis, Université Paris-Saclay (ComUE), 2019. http://www.theses.fr/2019SACLS326/document.

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Les virus sont connus pour infecter toutes les classes d’organismes vivants sur Terre, qu’elles soient végétales ou animales. Les virions consistent en un génome d'acide nucléique protégé par une enveloppe protéique unique ou multicouche appelée capside et, dans certains cas, par une enveloppe de lipides. La capside virale est généralement composée de centaines ou de milliers de protéines formant des structures ordonnées. La moitié des virus connus présentent une symétrie icosaédrique, les autres étant hélicoïdaux, prolats ou de structure irrégulière complexe. Récemment, les particules virales ont attiré une attention croissante en raison de leur structure extrêmement régulière et de leur utilisation potentielle pour la fabrication de nanostructures ayant diverses fonctions. Par conséquent, la compréhension des mécanismes d'assemblage sous-jacents à la production de particules virales est non seulement utile au développement d'inhibiteurs à des fins thérapeutiques, mais elle devrait également ouvrir de nouvelles voies pour l'auto-assemblage de matériaux supramoléculaires complexes. À ce jour, de nombreuses études expérimentales et théoriques sur l'assemblage de virus ont été effectuées. Des recherches expérimentales ont permis d'obtenir de nombreuses informations sur l'assemblage du virus, y compris les conditions appropriées requises pour l'assemblage et les voies cinétiques. En combinant ces informations et méthodes théoriques, une première compréhension du mécanisme d'assemblage des virus a été élaborée. Cependant, les informations provenant uniquement d'expériences ne peuvent donner une image complète, en particulier à l'échelle microscopique. Par conséquent, dans cette thèse, nous avons utilisé des simulations informatiques, y compris des techniques de Monte Carlo et de la dynamique moléculaire, pour sonder l’assemblage du virus, dans l’espoir de mieux comprendre les mécanismes moléculaires en jeu
Viruses are known for infecting all classes of living organisms on Earth, whether vegetal or animal. Virions consist of a nucleic acid genome protected by a single or multilayered protein shell called capsid, and in some cases by an envelope of lipids. The viral capsid is generally made of hundreds or thousands of proteins forming ordered structures. Half of all known viruses exhibit an icosahedral symmetry, the rest being helical, prolate or having a complex irregular structure. Recently, viral particles have attracted an increasing attention due to their extremely regular structure and their potential use for fabricating nanostructures with various functions. Therefore, understanding the assembly mechanisms underlying the production of viral particles is not only helpful to the development of inhibitors for therapeutic purpose, but it should also open new routes for the self-assembly of complex supramolecular materials. To date, numerous experimental and theoretical investigations on virus assembly have been performed. Through experimental investigations, a lot of information have been obtained on virus assembly, including the proper conditions required for the assembly and the kinetic pathways. Combining those information and theoretical methods, an initial understanding of the assembly mechanism of viruses has been worked out. However, information coming purely from experiments cannot give the whole picture, in particular at a microscopic scale. Therefore, in this thesis, we employed computer simulations, including Monte Carlo and molecular dynamics techniques, to probe the assembly of virus, with the expectation to gain new insights into the molecular mechanisms at play

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Thorner, Gentien. "Nanostructures de titanate de Baryum : modélisation,simulations numériques et étude expérimentale." Thesis, Université Paris-Saclay (ComUE), 2016. http://www.theses.fr/2016SACLC093/document.

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Des simulations numériques conduites sur un ferroélectrique, le Titanate de Baryum, permettent d'extraire les températures où se produisent les transitions pour chacune des composantes et elles utilisent le plus souvent des conditions limites périodiques. Cependant, il est possible de modifier la simulation de manière à rendre compte d'une particule isolée, et les conditions limites électriques de type court-circuit ou bien circuit ouvert affectent alors le résultat. Réduire la taille accorde encore davantage d'importance à de tels effets de surface par rapport aux effets de volume. Expérimentalement, la formation de nanocubes creux ou de nanotores a été observéelors de synthèses solvothermales. De possibles mécanismes de morphogénèse sont évoqués. Dans ce travail, les simulations ont ensuite été conduites sur des particules nanométriques, dont les formes avaient été obtenues expérimentalement. Pour des cubes creux, il a été constaté que la taille de l'inclusion vide modifiait la valeur du coefficient d'écrantage critique à partir duquel le comportement de la polarisation passe d'une configuration de type court-circuit à une configuration de type circuit fermé. Pour des nanotores aux basses températures, une modification du rapport entre petit et grand rayon donne lieu à des configurations possédant un moment toroïdal seul ou accompagné d'un moment hypertoroïdal voire d'oscillations de ce dernier
Numerical simulations performed on a ferroelectric, Barium Titanate, yield all the transition temperatures under periodic boundary conditions. However, the same simulation can be modified to model an isolated particle under short-circuit or opencircuit electrical boundary conditions. Reducing size makes these surface effects even more important with regard to volume effects.From an experimental point of view, solvothermal synthesis of hollow nanocubesand nanotori is reported and various morphogenesis mechanisms are listed.In this work, simulations were performed on nanometric particles that had experimentally obtained shapes. In hollow cubes, it was shownthat the hole size changed the numerical value of the critical screening coefficient at which the system changes its behavior from aconfiguration that is short-circuit like to another one that is open-circuit like. For nanotori at low temperatures, a modification of the ratio between torus minor and major radius gives either configurations with only toroidalmoment or configurations in which it coexists with homogeneous or oscillating hypertoroidal moment

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Varnik, Fathollah. "Molekulardynamik-Simulationen zum Glasübergang in makromolekularen Filmen (Molecular dynamics simulations on the glass transition in macromolecular films) /." [S.l. : s.n.], 2000. http://ArchiMeD.uni-mainz.de/pub/2001/0007/diss.pdf.

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Hasan, Syed Sharjeel Ul, and Shabbir Ahmed Khan. "Perceptions of students who participated in business simulation at Umeå School of Business, Sweden : A model for educational simulations." Thesis, Umeå universitet, Handelshögskolan vid Umeå universitet, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-46462.

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Purpose: The goal of this study is to emphasize the use of business simulation as a learning tool in educational institutions. For instance, the two master’s programs (marketing & entrepreneurship, provided by Umeå Business School at master’s level), comprised of four core courses each, but only one module out the four provided utilized simulation for learning purpose. Generally self study, class lectures and case studies are used as the main pedagogy tools in the class room setting. In case of Umeå Business School, the use of simulations and gaming was rather limited in Umea School of Business (USBE) despite the fact that simulations are used to the point of saturation in American universities. This research is focused towards exploring the perceptions of students who undertook a business simulation at Umeå Business School, Sweden. Furthermore, it also provides a model for an effective simulation from educational point of view. Method: Hypotheses were developed to investigate the perceptions held by the students at USBE regarding their perceived effectiveness of simulation as a learning tool. A deductive approach was followed by using theories and scientific research by which hypotheses were generated and tested for answering the literature gaps. Quantitative research strategy was used and questionnaires were sent only to qualified respondents (those students of USBE who had already taken simulation at least once in any modules of their study tenure). Hypotheses were generated to find out correlations between the variables and tested through Pearson coefficient using SPSS testing methods. Findings/conclusion: The findings revealed that students consider simulation the most learning tool compared to others. Simulation is considered practical learning, learning through a gaming approach, an exercise that replicates realistic environment in class room. It provides an enjoyable way of learning and the retention of learnt concept is in high to medium range. Empirical findings show that there is a positive correlation between the variable students who would like to use simulation again with the variable that students will register a course which provides simulation. There is a strong positive correlation among variable of perceiving simulation as exciting and variable perceiving it as a fun way of learning. Positive correlation exists among variables of being excited to know of simulation in a course and variable of considering simulation being a learning experience. Lastly we found that there is positive and highest correlation in perception of students regarding likeness and learning with regards to simulation. This means that compared to other tools there is more likeness of simulation amongst students and they perceive it as most learning tool compared to class lectures, guest lectures, self study and group discussions. The study concluded with providing a basic model of an effective simulation which was developed in line with literature review and empirical findings from this research

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46

Congedo, Pietro Marco. "Contributions to the reliability of numerical simulations in fluid mechanics. Application to the flow simulation of thermodynamically complex gases." Habilitation à diriger des recherches, Université Sciences et Technologies - Bordeaux I, 2013. http://tel.archives-ouvertes.fr/tel-00940088.

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At the interface of physics, mathematics, and computer science, Uncertainty Quanti cation (UQ) aims at developing a more rigorous framework and more reliable methods to characterize the impact of uncertainties on the prediction of Quantities Of Interest (QOI). Despite signi cant improvements done in the last years in UQ methods for Fluid Mechanics, there is nonetheless a long way to go before there can be talk of an accurate prediction when considering all the numerous sources of uncertainties of the physical problem (boundary conditions, physical models, geometric tolerances, etc), in particular for shock-dominated problems. This manuscript illustrates my main contributions for improving the reliability of the numerical simulation in Fluid Mechanics: i) the development of e cient and exible schemes for solving at low-cost stochastic partial di erential equations for compressible ows, ii) various works concerning variancebased and high-order analysis, iii) the design of some low-cost techniques for the optimization under uncertainty. The application of interest is the robust design of turbines for Organic Rankine Cycles (ORC). Some contributions to the numerical ow prediction of the thermodynamically complex gases involved in ORC will be presented. This manuscript is divided in two parts. In the rst part, some intrusive algorithms are introduced that feature an innovative formulation allowing the treatment of discontinuities propagating in the coupled physical/stochastic space for shock-dominated compressible ows. Then, variance and higher-order based decompositions are described, that could alleviate problems with large number of uncertainties by performing a dimension reduction with an improved control. Some ANOVAbased analyses are also applied to several ows displaying various types of modeling uncertainties, be it cavitation, thermodynamic or turbulence modeling. Two algorithms for handling stochastic inverse problems are then introduced for improving input uncertainty characterization by directly using experimental data. Finally, robust-optimization algorithms are introduced, that are e cient when dealing with a large number of uncertainties, relying on di erent formulations, i.e. with decoupled/ coupled approaches between the stochastic and the optimization solvers. The second part is devoted to the study of dense gas ow in ORC-cycles, which represent a highly demanding eld of application as far as ow simulation reliability is concerned. The numerical ingredients necessary for this kind of simulation are described. Then, some recent results are illustrated : i) high- delity turbine computations; ii) a feasibility study concerning the appearance and the occurrence of a Rarefaction Shock Wave, using experimental data and di erent operating conditions (in monophasic and two-phase ows); iii) a stochastic study concerning the thermodynamic model uncertainties. This set of research works has produced several papers in international journals and peer-reviewed conferences.

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Zehe, Daniel [Verfasser], Alois [Akademischer Betreuer] Knoll, Wentong [Gutachter] Cai, and Alois [Gutachter] Knoll. "Cloud Simulation for Large-Scale Agent-Based Traffic Simulations / Daniel Zehe ; Gutachter: Wentong Cai, Alois Knoll ; Betreuer: Alois Knoll." München : Universitätsbibliothek der TU München, 2019. http://d-nb.info/119189715X/34.

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Yoginath, Srikanth B. "Virtual time-aware virtual machine systems." Diss., Georgia Institute of Technology, 2014. http://hdl.handle.net/1853/52321.

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Discrete dynamic system models that track, maintain, utilize, and evolve virtual time are referred to as virtual time systems (VTS). The realization of VTS using virtual machine (VM) technology offers several benefits including fidelity, scalability, interoperability, fault tolerance and load balancing. The usage of VTS with VMs appears in two ways: (a) VMs within VTS, and (b) VTS over VMs. The former is prevalent in high-fidelity cyber infrastructure simulations and cyber-physical system simulations, wherein VMs form a crucial component of VTS. The latter appears in the popular Cloud computing services, where VMs are offered as computing commodities and the VTS utilizes VMs as parallel execution platforms. Prior to our work presented here, the simulation community using VM within VTS (specifically, cyber infrastructure simulations) had little awareness of the existence of a fundamental virtual time-ordering problem. The correctness problem was largely unnoticed and unaddressed because of the unrecognized effects of fair-share multiplexing of VMs to realize virtual time evolution of VMs within VTS. The dissertation research reported here demonstrated the latent incorrectness of existing methods, defined key correctness benchmarks, quantitatively measured the incorrectness, proposed and implemented novel algorithms to overcome incorrectness, and optimized the solutions to execute without a performance penalty. In fact our novel, correctness-enforcing design yields better runtime performance than the traditional (incorrect) methods. Similarly, the VTS execution over VM platforms such as Cloud computing services incurs large performance degradation, which was not known until our research uncovered the fundamental mismatch between the scheduling needs of VTS execution and those of traditional parallel workloads. Consequently, we designed a novel VTS-aware hypervisor scheduler and showed significant performance gains in VTS execution over VM platforms. Prior to our work, the performance concern of VTS over VM was largely unaddressed due to the absence of an understanding of execution policy mismatch between VMs and VTS applications. VTS follows virtual-time order execution whereas the conventional VM execution follows fair-share policy. Our research quantitatively uncovered the exact cause of poor performance of VTS in VM platforms. Moreover, we proposed and implemented a novel virtual time-aware execution methodology that relieves the degradation and provides over an order of magnitude faster execution than the traditional virtual time-unaware execution.

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49

Drewniak, Marta. "Computer Simulations of Dilute Polymer Solutions: Chain Overlaps and Entanglements." Thesis, University of North Texas, 1996. https://digital.library.unt.edu/ark:/67531/metadc278086/.

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Abstract:

Chain conformations and the presence of chain overlaps and entanglements in dilute polymer solutions have been analyzed. The fundamental problem of existence of chain overlaps in dilute solutions is related to the drag reduction phenomenon (DR). Even though DR occurs in solutions with the concentration of only few parts per million (ppm), some theories suggest that entanglements may play an important role in DR mechanism. Brownian dynamics technique have been used to perform simulations of dilute polymer solutions at rest and under shear flow. A measure of interchain contacts and two different measures of entanglements have been devised to evaluate the structure of polymer chains in solution. Simulation results have shown that overlaps and entanglements do exist in static dilute solutions as well as in solutions under shear flow. The effect of solution concentration, shear rate and molecular mass have been examined. In agreement with the solvation theory of DR mechanism, simulation results have demonstrated the importance of polymer + polymer interactions in dilute solutions.

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50

Littler, Matthew Laws 1973. "Simulating the Long House Valley: An evaluation of the role of agent-based computer simulation in archaeology." Thesis, The University of Arizona, 1998. http://hdl.handle.net/10150/278685.

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Abstract:

This study presents the results of a detailed analysis of an agent-based computer simulation called Artificial Anasazi. The simulation attempts to replicate the population growth and settlement patterns of the prehistoric Kayenta Anasazi of Long House Valley in northeastern Arizona between A.D. 400-1300. Agent-based simulations model social evolution from the bottom-up, using heterogeneous agents that follow simple rules, in contrast to the top-down computer simulations usually used by archaeologists. Artificial Anasazi is tested against the archaeological record of the real Long House Valley through both qualitative and quantitative methods, and an analysis of the relevant ethnographic information is presented. The ultimate goal of this study is to elucidate the potentials and pitfalls of using agent-based computer simulation as a serious research tool in archaeology.

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