This thesis outlines the dynamic system analysis of a 3D Ultrasonic neuro- navigation system for use in motion capture studies. The work entails the development and implementation of methods for achieving the same. The objective of the project is to come up with an accurate dynamic 3D ultrasonic neuro-navigation system which can deliver up to sub mm accuracy within the operating workspace for use in image guided neuro surgery. The major focus of the work is to come up with a second order Kalman filter which can take out the outliers occurring in a static system in real time, thereby making the system more robust and accurate. Once the filter achieves the requisites, it can be integrated into the current motion tracking software which allows for the real time tracking of transmitters, hence the points of interest.

Entrepreneurs face constraints that more mature organizations may not. These constraints cause unique pressures within entrepreneurship. Although ethics and entrepreneurship have individually received much attention in the academic literature, not enough research has investigated ethics within entrepreneurship. This study addresses the need of ethics research within entrepreneurship. Utilizing the theory of planned behavior, this research investigates the ethical decision making process of entrepreneurs. Not all ethical situations are created equally, and not all entrepreneurs are created equally. The ethical environment of any situation can be financially concerned or socially concerned. Likewise, entrepreneurs can be motivated by a private financial gain or a social impact. A multi-scenario approach known as policy-capturing is used to examine the relative importance entrepreneurs place on attitude, subjective norms, perceived behavioral control (PBC), and self-identity when faced with a financial and a social ethical decision. The findings suggest that the environment does affect the ethical decision making process as defined by the relative importance of the variables. Within each environment, personal demographic variables of entrepreneurs were also found to affect their ethical decision making process. Such variables included entrepreneurial orientation, gender, love of money, financial security, spirituality/religiosity, idealism, and relativism. By considering the effects of the ethical environment along with the demographics of the entrepreneur, potential investors may be able to more accurately gauge investment opportunities. Implications of the findings, limitations of the study, and future research areas are discussed.

Dans l'industrie du pétrole et des moteurs, les écoulements de fluides non-miscibles sont fréquemment rencontrés : écoulements d'hydrocarbures dans les conduites, séparation en production, injection de carburant dans les moteurs, procédés de raffinage, etc.Pour modéliser ce type d'écoulement, deux approches sont possibles. Soit l'écoulement est décrit de façon macroscopique et les phénomènes locaux (rupture et coalescence des gouttes, glissement des phases, compaction locale, etc.) sont modélisés à l'aide de lois de fermeture analytiques ou empiriques. Soit l'écoulement est modélisé de manière directe à l'échelle de la goutte et on s'attache à décrire précisément l'interface et les interactions entre les phases. C'est cette dernière approche que nous avons proposé d'adopter pour étudier des écoulements à phase dispersée liquide-liquide, et plus particulièrement les phénomènes de rupture et coalescence, collision ou déformation de gouttes. Ainsi, le but principal de ce travail de thèse a été le développement d'un code de simulation numérique directe capable de modéliser un écoulement diphasique liquide-liquide, afin d'étudier en détail les effets de coalescence et de rupture entre les gouttes. Ce travail a nécessité l’utilisation d’une technique de suivi d’interface appropriée et le développement d’un solveur des équations de Navier-Stokes incompressible pour calculer le champ de vitesse, ainsi qu’une méthode de couplage entre ces deux solveurs pour la simulation des écoulements diphasiques. Notre outil numérique a été validé sur de nombreux cas tests académiques et appliqué à l'étude du processus de séparation liquide-liquide. / The flow of immiscible fluids is a frequent issue in the petroleum industry: hydrocarbon in pipelines, separation process for production, fuel injection in engines, refinery treatment processes, etc.There are two possible approaches to model this type of flow. In the first one, the flow is described macroscopically. In this case, local phenomena (breakage or coalescence of droplets, phase slip, local compaction) are modeled thanks to analytic closure laws or empiric laws. In the second approach, the flow is simulated indirectly on a scale of droplet and we want to describe precisely the interface and the interactions between phases. We propose here to consider the second method to study liquid/liquid dispersed flows and especially the phenomena of breakage or coalescence and collision or distortion of the droplets.Thus, the main purpose of this work was the development of a direct numerical simulation code that is capable to model a liquid-liquid two-phase flow, in order to study in detail the effects of droplets coalescence and breakage. To model a two-phase flow, it is necessary to choose an appropriate interface tracking method and to develop a solver for Navier-Stokes incompressible equations to compute the velocity and pressure values. Also, a coupling method that is able to handle the discontinuous quantities at the interface has to be implemented. Our numerical tool has been validated on numerous academic test cases and applied to study the process of liquid-liquid separation.

abstract: The Volume-of-Fluid method is a popular method for interface tracking in Multiphase applications within Computational Fluid Dynamics. To date there exists several algorithms for reconstruction of a geometric interface surface. Of these are the Finite Difference algorithm, Least Squares Volume-of-Fluid Interface Reconstruction Algorithm, LVIRA, and the Efficient Least Squares Volume-of-Fluid Interface Reconstruction Algorithm, ELVIRA. Along with these geometric interface reconstruction algorithms, there exist several volume-of-fluid transportation algorithms. This paper will discuss two operator-splitting advection algorithms and an unsplit advection algorithm. Using these three interface reconstruction algorithms, and three advection algorithms, a comparison will be drawn to see how different combinations of these algorithms perform with respect to accuracy as well as computational expense. / Dissertation/Thesis / Masters Thesis Mechanical Engineering 2015

abstract: Many physical phenomena and industrial applications involve multiphase fluid flows and hence it is of high importance to be able to simulate various aspects of these flows accurately. The Dynamic Contact Angles (DCA) and the contact lines at the wall boundaries are a couple of such important aspects. In the past few decades, many mathematical models were developed for predicting the contact angles of the inter-face with the wall boundary under various flow conditions. These models are used to incorporate the physics of DCA and contact line motion in numerical simulations using various interface capturing/tracking techniques. In the current thesis, a simple approach to incorporate the static and dynamic contact angle boundary conditions using the level set method is developed and implemented in multiphase CFD codes, LIT (Level set Interface Tracking) (Herrmann (2008)) and NGA (flow solver) (Desjardins et al (2008)). Various DCA models and associated boundary conditions are reviewed. In addition, numerical aspects such as the occurrence of a stress singularity at the contact lines and grid convergence of macroscopic interface shape are dealt with in the context of the level set approach. / Dissertation/Thesis / Masters Thesis Mechanical Engineering 2015

Turbulent combustion has a profound effect on the way we live our lives; homes and businesses predominantly rely on power generated by burning some form of fuel, and the vast majority of transport of passengers and cargo are driven by combustion. Fossil fuels remain readily available and relatively cheap, and so will continue to power the modern world for the foreseeable future. Combustion of fossil fuels produces emissions that detrimentally affect air quality, particularly in highly-populated cities, and are also widely believed to be contributing to global climate change. Consequently, increasing attention is being focused on alternative fuels, increased efficiency and reduced emissions. One alternative fuel is hydrogen, which introduces challenges in end-usage, storage and safety that are not encountered with more conventional fuels. Advances in computational power and software technology means that numerical simulation has a growing role in the development of combustors and safety evaluation. Despite these advances, many challenges remain; the broad range of time and length scales involved are coupled with complex thermodynamics and chemistry on top of turbulent fluid mechanics, which means that detailed simulations of even relatively-simple burners are still prohibitively expensive. Engineering turbulent flame models are required to reduce computational expense, and the challenge is to retain as much of the flow physics as possible. Furthermore, the choice of numerical approach has a significant effect on the quality of simulation, and different target applications place different demands on the numerical scheme. In the case of hydrogen explosion, the approach needs to be able to capture a range of physical behaviours including turbulence, low-speed deflagration, high-speed shock waves and potentially detonations. One such numerical approach that has enjoyed widespread success is finite volumes schemes based on the Godunov method. These methods perform well at all speeds, and have positive shock-capturing capability, but recent studies have demonstrated difficulties with numerical stability for more complex thermodynamics, specifically in the case of fully-conservative methods for multi-component fluids with varying thermodynamic properties. A recent development is the so-called double-flux method, which retains many of the positive properties of the fully-conservative approaches and does not suffer from the same numerical instabilities, but is quasi-conservative and involves additional computational expense. The present work consolidates the state-of-the-art in the literature, and considers two equation sets, based on mass fraction and volume fraction, respectively, along with fully-conservative and quasiconservative schemes. Comprehensive validation and evaluation of the different approaches is presented. It was found that both quasi-conservative approaches performed well, with a better conservative behaviour for the quasi-conservative volume fraction, but a better stability for the quasi-conservative mass fraction. Finally, the numerical tool developed is applied to turbulent combustion of premixed hydrogen in the context of the semi-confined experiments from the University of Sydney. The LES results showed an good overall agreement with the experimental data, and the critical parameters such as overpressure and flame speed where globally well captured, highlighting the large potential of LES for safety analysis.

Kyoto University (京都大学) / 0048 / 新制・課程博士 / 博士(工学) / 甲第14913号 / 工博第3140号 / 新制||工||1471(附属図書館) / 27351 / UT51-2009-M827 / 京都大学大学院工学研究科社会基盤工学専攻 / (主査)教授 中川 一, 教授 関口 秀雄, 教授 藤田 正治 / 学位規則第4条第1項該当

In this study, we test the assumption that the way target firm employees respond to a takeover is contingent on their national origin. The antecedents of target firm member trust in the acquiring firm management were examined in a cross-national sample of German and Singaporean employees using a policy-capturing design. Five factors hypothesized to affect target firm member trust after a takeover were found to be significant influences on employees' trust judgments in a decision-making simulation: (i) combining firms' collaboration history, (ii) mode of takeover, (iii) whether it was a domestic or cross-border acquisition, (iv) degree of autonomy removal, and (v) attractiveness of the acquiring firm's human resource policies and reward system. Further analyses suggest that the relative importance of these factors in predicting target firm employees' reactions to a takeover varies depending on their national origin. We conclude that companies engaged in cross-border acquisitions need to consider contingencies in the cultural and institutional contexts in which the acquired firms are embedded and adapt their approaches for integrating them accordingly.

Master thesis deals with the possibility of using virtual reality in the construction process and points to new possibilities for non-traditional controlling of devices. The aim of this thesis is to become familiar with equipment designed in ÚVSSR and technology using motion capturing. Subsequently, there is also aim to use the gained knowledge to design a software which uses virtual reality in the construction process of parallel kinematic structure delta type, which will have the option of touchless control and will analyze the progress of energy flow of devices.

Digitale Menschmodelle ermöglichen die Simulation von Arbeitstätigkeiten in prototypischen Fabrikumgebungen. Eine korrekte Aktionsausführung des virtuellen Werkers ist dabei von zentraler Bedeutung. Die Entwicklung von Methoden zur Synthese realistischer und kollisionsfreier Bewegungen stellt einen Schwerpunkt dieser Arbeit dar. Auf Basis von Motion-Capture-Daten werden Bewegungsräume der Aktionen mittels Tensorprodukt B-Splines und Fourierreihen approximiert. Der Einsatz von Bewegungsgraphen ermöglicht die automatische Synthese komplexer Bewegungsabfolgen. Mit Hilfe des menschähnlichen Eingabegeräts PuppID sind intuitive Anpassungen und Individualisierungen der Bewegungen möglich. Das Ergebnis dieser Dissertation stellt ein Gesamtsystem zur Erzeugung zielgerichteter und kollisionsfreier Bewegungen in veränderlichen Umgebungen dar.