The characteristics of liquid and solid aerosols have been intensively investigated by means of optical diagnostic techniques. Part I describes the characteristics of liquid aerosol formation formed by heat transfer fluids (HTFs) from bulk liquids. Part II investigates the characteristics of convective transport behavior of solid particles in virtual impactor (VI). The objective of part I is to establish correlations which offer predictions on atomized particle size of HTFs which are widely and commonly used in process industries. There are numerous reports stating that mist explosions formed from leakage cause disastrous accidents in process industries. For safety concerns, the characteristics of mist formation should be known in order to prevent HTFs from catching on fire or exploding. The empirical data on formation of mist are collected by the optical measurement technique, the Fraunhofer diffraction. The Buckingham-PI theorem is applied to establish a correlation between empirical data and representative physical properties of HTFs. Final results of correlations are solved by a statistical method of linear regression. The objective of part II is to investigate the characteristics of convective transport behavior in virtual impactor (VI) which is used to sort polydisperse precursor powder in the process industries of superconductor wire. VI is the device to separate polydisperse particles as a function of particle size by using the difference in inertia between different sizes of particles. To optimize VI performance, the characteristics of convective transport should be identified. This objective is achieved by visualization techniques. The applied visualization techniques are Mie-scattering and laser induced fluorescence (LIF). To investigate analytically, a local Stokes number is introduced in order to offer criteria on predicting the efficiency of VI performance and boundary effect on particle separation. The achieved results can enhance performance and eliminate defects by having knowledge of the behavior of solid particles in VI.

This interdisciplinary research project combines the fields of nautical archaeology and computer visualization to create an interactive virtual reconstruction of the 1606 Portuguese vessel Nossa Senhora dos Mártires, also known as the Pepper Wreck. Using reconstruction information provided by Dr. Filipe Castro (Texas A&M Department of Anthropology), a detailed 3D computer model of the ship was constructed and filled with cargo to demonstrate how the ship might have been loaded on the return voyage from India. The models are realistically shaded, lighted, and placed into an appropriate virtual environment. The scene can be viewed using the real-time immersive and interactive system developed by Dr. Frederic Parke (Texas A&M Department of Visualization). The process developed to convert the available information and data into a reconstructed 3D model is documented. This documentation allows future projects to adapt this process for other archaeological visualizations, as well as informs archaeologists about the type of data most useful for computer visualizations of this kind.

In order to make the task of controlling Mobile-Manipulator Systems (MMS) simpler, a novel command strategy that uses a single joystick is presented to replace the existing paradigm of using multiple joysticks. To improve efficiency and accuracy, virtual fixtures were implemented with the use of a haptic joystick. Instead of modeling the MMS as a single unit with three redundant degrees-of-freedom (DOF), the operator controls either the manipulator or the mobile base, with the command strategy choosing which one to move. The novel command strategy uses three modes of operation to automatically switch control between the manipulator and base. The three modes of operation are called near-target manipulation mode, off-target manipulation mode, and transportation mode. The system enters near-target manipulation mode only when close to a target of interest, and allows the operator to control the manipulator using velocity control. When the operator attempts to move the manipulator out of its workspace limits, the system temporarily enters transportation mode. When the operator moves the manipulator in a direction towards the manipulator’s workspace the system returns to near-target manipulation mode. In off-target manipulation mode, when the operator moves the manipulator to its workspace limits, the system retracts the arm near to the centre of its workspace to enter and remain in transportation mode. While in transportation mode the operator controls the base using velocity control. Two types of virtual fixtures are used, repulsive virtual fixtures and forbidden region virtual fixtures. Repulsive virtual fixtures are present in the form of six virtual walls forming a cube at the manipulator’s workspace limits. When the operator approaches a virtual wall, a repulsive force is felt pushing the operator’s hand away from the workspace limits. The forbidden region virtual fixtures prevent the operator from driving into obstacles by disregarding motion commands that would result in a collision. The command strategy was implemented on the Omnibot MMS and test results show that it was successful in improving simplicity, accuracy, and efficiency when teleoperating a MMS. / UOIT

The notion of finite type invariants of virtual knots, introduced by Goussarov, Polyak and Viro, leads to the study of the space of diagrams with directed chords mod 6T (also known as the space of arrow diagrams), and weight systems on it. It is well known that given a Manin triple together with a representation we can construct a weight system. In the first part of this thesis we develop combinatorial formulae for weight systems coming from standard Manin triple structures on the classical Lie algebras and these structures' defining representations. These formulae reduce the problem of finding weight systems in the defining representations to certain counting problems. We then use these formulae to verify that such weight systems, composed with the averaging map, give us the weight systems found by Bar-Natan on (undirected) chord diagrams mod 4T. In the second half of the thesis we present results from computations done jointly with Bar-Natan. We compute, up to degree 4, the dimensions of the spaces of arrow diagrams whose skeleton is a line, and the ranks of all classical Lie algebra weight systems in all representations. The computations give us a measure of how well classical Lie algebras capture the spaces of arrow diagrams up to degree 4, and our results suggest that in degree 4 there are already weight systems which do not come from the standard Manin triple structures on classical Lie algebras.

A virtual holonomic constraint (VHC) for an Euler-Lagrange Control System is a smooth relation between the configuration variables that can be made invariant through application of suitable feedback. In this thesis we investigate the role played by VHCs in the synchronization of Euler-Lagrange systems. We focus on two problems. For $N$ underactuated cart-pendulums, we design a smooth feedback that fully synchronizes the cart-pendulums while simultaneously stabilizing a periodic orbit corresponding to a desired oscillation for the pendulums. A by-product of our results is the ability to simultaneously synchronize the pendulums and stabilize the unstable upright equilibrium. The second synchronization problem investigated in this thesis is bilateral teleoperation, whereby a master robot is operated by a human while a slave robot synchronizes to the master. For two identical planar manipulators, we develop a methodology to achieve teleoperation in the presence of a hard surface, with simultaneous force control.

A virtual holonomic constraint (VHC) for an Euler-Lagrange Control System is a smooth relation between the configuration variables that can be made invariant through application of suitable feedback. In this thesis we investigate the role played by VHCs in the synchronization of Euler-Lagrange systems. We focus on two problems. For $N$ underactuated cart-pendulums, we design a smooth feedback that fully synchronizes the cart-pendulums while simultaneously stabilizing a periodic orbit corresponding to a desired oscillation for the pendulums. A by-product of our results is the ability to simultaneously synchronize the pendulums and stabilize the unstable upright equilibrium. The second synchronization problem investigated in this thesis is bilateral teleoperation, whereby a master robot is operated by a human while a slave robot synchronizes to the master. For two identical planar manipulators, we develop a methodology to achieve teleoperation in the presence of a hard surface, with simultaneous force control.

Virtual worlds are online communities that enable user interaction via avatars in a computer-based simulated environment. In recent years, the fast growth of virtual worlds and their enormous potential for various applications have attracted much attention. Though the uses of virtual worlds are becoming numerous in diverse fields, the core issue for their development from the perspective of gamers is to maximize user immersion. This paper tackles the issue from the perspective of game designers and explores the immersive dimensions of users via an experiment. The experimental platform is a specific virtual world, Second Life, and a particular gaming situation, dancing. The main manipulation involves altering the graphic realism level of both the avatar¡¯s appearance and the dancing environment. The research aims to find out whether there is a correlation between graphic realism and user immersion and, if there is, what element(s) or degrees of realism will lead to different levels of user immersion.

No description available.

Un dels avantatges d'usar plataformes virtuals o prototipat virtual enlloc del maquinari real pel desenvolupament de programari encastat és la capacitat d'alguns simuladors de fer captures del seu estat. Si el model del sistema complet és prou detallat, pot tardar uns quants minuts (inclús hores) per simular l'engegada d'un Sistema Operatiu. Si es pren una captura just després de que ha acabat d'engegar, cada cop que calgui corre el programari encastat, els dissenyadors poden simplement recuperar la captura i continuar-la. Recuperar una captura normalment porta pocs segons. Aquest guany es trasllada en una major productivitat, especialment quan es treballa amb sistemes encastat, amb programari complex sobre Sistemes Operatius com en els dispositius actuals. En aquesta tesi es presenta en primer lloc el treball realitzat per afegir un llenguatge de descripció de sistemes anomenat SystemC a dues plataformes virtuals diferents. Aquesta tasca es realitzà per una eina comercial i desprès es traslladà a una plataforma de codi obert. També es presenta una sèrie de modificacions al llenguatge SystemC per suportar la captura d'instantànies. Aquestes modificacions faran possible poder agafar l'estat de la simulació en SystemC i salvar-les al disc. Més tard, la simulació es pot recuperar en el mateix estat on es trobava, sense canvis en els seus components. Aquestes millores ajudaran al llenguatge SystemC a ser més àmpliament usat en el món de les Plataformes Virtuals. / One advantage of using a virtual platform or virtual prototype over real hardware for embedded software development and testing is the ability of some simulators to take checkpoints of their state. If the entire system model is detailed enough, it might take several minutes (or even hours) to simulate booting the O.S. If a snapshot of the simulation is saved just after it has finished booting, each time it is necessary to run the embedded software, designers can simply restore the snapshot and go. Restarting a checkpoint typically takes a few seconds. This can translate into a major productivity gain, especially when working with embedded system with complex SW stacks and O.S. like modern embedded devices. In this dissertation we present in firstly our work on adding a description level language as SystemC to two Virtual Platforms. This work was done for a commercial Virtual Platform, and later translated to a open-sourced Platform. This thesis also presents a set of modifications to SystemC language to support checkpointing. These modifications will make it possible to take the state of a SystemC running simulation and save it to disk. Later, the same simulation can be restored to the same point it was before, without any change to the simulated modules. These changes would help SystemC to be suitable for use by Virtual Platforms as a description language.

The methods of preserving cultural heritage are becoming increasingly digital, and with this development it is becoming all the more open to public scrutiny. The field of virtual heritage and their applications, which digitally preserve cultural heritage using virtual reality, are struggling to live up to the expectations of the public. The virtual heritage field has begun to look for solutions to their problems in other fields, such as that of video games. This thesis identifies 17 elements which are sought after for incorporation in virtual heritage applications, by conducting a literature review of recent virtual heritage research and organizing the findings into a matrix. The occurrence of the identified elements in four different modern entertainment video games is further analyzed and described. The resulted element matrix and game reviews could be used in the future development of virtual heritage applications, and of cultural heritage or historical video games.