Dissertations / Theses on the topic 'Real time virtual environment'
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Shah, Radhey. "SUPPORTING REAL-TIME PDA INTERACTION WITH VIRTUAL ENVIRONMENT." Master's thesis, University of Central Florida, 2004. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/3555.
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Personal Digital Assistants (PDAs) are becoming more and more powerful with advances in technology and are expanding their applications in a variety of fields. This work explores the use of PDAs in Virtual Environments (VE). The goal is to support highly interactive bi-directional user interactions in Virtual Environments in more natural and less cumbersome ways. A proxy-based approach is adopted to support a wide-range of handheld devices and have a multi-PDA interaction with the virtual world. The architecture consists of three components in the complete system, a PDA, a desktop that acts as a proxy and Virtual Environment Software Sandbox (VESS), software developed at the Institute for Simulation and Training (IST). The purpose of the architecture is to enable issuing text and voice commands from PDA to virtual entities in VESS through the proxy. The commands are a pre-defined set of simple words such as 'move forward', 'turn right', 'go', and 'stop'. These commands are matched at the proxy and sent to VESS as text in XML format. The response from VESS is received at the proxy and forwarded back to the PDA. Performance measures with respect to response time characteristics of text messages between PDA and proxy over Wi-Fi networks are conducted. The results are discussed with respect to the acceptable delays for human perception in order to have real-time interaction between a PDA and an avatar in virtual world.M.S.
Other
Engineering and Computer Science
Modeling and Simulation
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Wu, Wenyan. "A reconfigurable virtual environment based on real time data." Thesis, University of Derby, 2003. http://hdl.handle.net/10545/324818.
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The objective of this research is to design a reconfigurable virtual environment, which can be reconfigured directly by the user or by using real time engineering data. The proposed reconfigurable virtual environment architecture is intended to improve flexibility and usability in a range of virtual environment applications. This research proposes a novel hybrid approach that relies on the concept of the integration and composition of the reconfiguration strategy with the process of designing virtual environment. It binds various reconfiguration rules with virtual objects in the virtual environment. Using this hybrid approach, an architecture of reconfigurable virtual environment has been established. The reconfigurable virtual environment provides a modular open system architecture with a set of extension interfaces, which have been implemented for communicating with different system components to realise data exchange in the reconfigurable virtual environment. A novel interface, which connects the virtual environment to the real environment, has been developed to facilitate communication and reconfiguration between them in real time. It can be used for virtual testing and visualisation of engineering applications, where users can interactively evaluate synthetic prototypes using YEs. An architecture, which can be used for design of a reconfigurable virtual environment has been developed. This architecture of the reconfigurable virtual environment integrates five system components, a virtual environment, data acquisition system, VE database and management system, mapping system between virtual and real environment, and the reconfigurable virtual environment application interface. An integrated development platform has been developed to realise communication between the virtual and the real environment. A reconfigurable virtual environment prototype has been implemented, which realises reconfiguring the virtual environment based on real time data, and allows hardware in the loop to be used.
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Corbett, Thomas Wingett. "XML-Driven Real-time Interactive Virtual Environment (XDRIVE) Engine." Thesis, Virginia Tech, 2006. http://hdl.handle.net/10919/79688.
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The XDRIVE engine is a runtime solution for the coordination and display of web-based multimedia presentations that feature three-dimensional content. This 3D content is rendered in real-time, which facilitates user-defined navigation and interaction with objects contained within the 3D virtual environment. These presentations can run independently, or they can be synchronized with audio and video files.
As web browsers interpret HTML formatted files, XDRIVE presentations are authored in and interpreted from XML formatted files, which are loaded and interpreted by the engine to display the defined content. Just as web browsers can load and display external files as guided and linked by the HTML tags, XDRIVE presentations rely on links to external files that are imported and displayed as guided by the XML tags.
Developed using Macromedia Director MX - a multimedia development software package - the XDRIVE engine itself is a Shockwave file that is embedded in a web page. Shockwave, a format whose browser plug-in is free to install and is loaded on a variety of systems, allows for the coordination of multiple media and data types, and features a powerful set of tools for the use of 3D content through the Shockwave3D format.
XDRIVE is designed to open the functionality of web-based 3D to a wider audience - allowing for custom presentations to be authored without a prerequisite knowledge of complicated programming languages, and 3D scripting. The XDRIVE engine is a series of scripted systems that utilize and connect various components of Director, and provide additional capabilities above those that already exist.Master of Science
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Wen, Zhigang. "Real time animated human agent in virtual environments." Thesis, University of Wolverhampton, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.413437.
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Ouyang, Xun. "Image synthesis of virtual environment construction for real time internet based e-learning." Thesis, University of Derby, 2010. http://hdl.handle.net/10545/232372.
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Shang, Huiping. "Real-time communication between virtual environments over the Internet." Thesis, University of Derby, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.269799.
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Malhotra, Priya. "Issues involved in Real-Time Rendering of Virtual Environments." Thesis, Virginia Tech, 2002. http://hdl.handle.net/10919/35382.
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This thesis explores the issues involved in modeling and rendering virtual environments with special emphasis on photo-realistic visualization and optimizing models for real-time applications.
Architectural walk-through systems are expected to give convincingly realistic interactive visualizations of complex virtual environments (Brooks, 1986). This pursued high degree impression of reality enhanced by interactivity, leads the user into a state of immersion, or the suspension of disbelief. The use of these systems ranges from virtual prototyping of building designs, stage and set lighting design, and architectural design reviews where the demands for greater realism and higher frame rates are always increasing. Until recently, the major focus has been on quickly rendering a complex model, rather than on photo-realism. The primary goal was reducing the number of graphics primitives rendered per frame without noticeably degrading image quality.
The aim of this research is to study some of the real-time rendering and illumination techniques, bringing out the limitations and advantages of each. In addition the study investigates the extent of inclusion of standard 3 Dimensional modeling packages in the methodology pipeline, providing architects and designers with some guidelines for photo-realistic visualization and real-time simulation of their models.
This is demonstrated through an example model of Tadao Ando's Church on the Water. A 3D photo-realistic reconstruction and real-time simulation is attempted, using widely available standard tools. The aim is to develop a methodology for building a compelling, interactive and highly realistic virtual representation. The whole methodology is based not on proprietary commercial 3D game engines, but on international open standard programming languages and API's, while leaving the user to freely select and use his/her 3D character-modeling package of choice. However, several shortcomings in both hardware and software became apparent. These are described, and a number of recommendations are provided.Master of Science
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Prior, Anthony. "Real-time collaborative volumetric virtual sculpting with haptic force-feedback." University of Western Australia. School of Computer Science and Software Engineering, 2008. http://theses.library.uwa.edu.au/adt-WU2009.0002.
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[Truncated abstract] Virtual sculpting is an interactive 3D modeling process that allows users to create and modify solid objects in a virtual world, with applications in art, rapid proto- typing and design. This thesis investigates methods for a collaborative, voxel-based virtual sculpting with haptic force-feedback. The objective is to devise such a system that operates in real-time. I make three main contributions in the fields of voxel-based virtual sculpting, haptics and collaborative virtual environments. First, I have devised a method for virtual sculpting where a voxel-based sculpture is created using a tool to build up or erode material. In existing real-time systems, due to the complexity of the algorithms that determine which voxels have been touched by the tool in a given time-step, the size or shape of the sculpting tool is limited and can often only be applied at a fixed orientation. My solution allows the tool to take the shape of any arbitrary triangle-based polyhedron that can be applied at any orientation. To determine which voxels are intersected by the tool, the tool is voxelized (converted into its discrete voxel representation) at each time-step against the voxels of the sculpture, which are then modified according to the desired operation. To give the resulting voxel-based sculpture a realistic appearance, I use the well-known Marching Cubes algorithm to form a triangular- mesh isosurface where the voxels representing sculpture material meet free-space. '...' For this I have borrowed concepts from the existing Voxmap-PointShell (VPS) model where the tool is represented by an array of points that cover its surface, each of which is tested for collisions with the sculpture. Each colliding point will form a component force, and the overall collision force is the vector sum of these components. My model is unique in that the component forces are formed in a direction tangential to the isosurface nearest the voxel of collision and can operate while the voxels of the sculpture are changing. While the VPS model is designed for force-feedback on a 6- degrees-of-freedom haptic device (delivers translational and rotational forces to the user), my model is designed to suit commodity 3-degrees-of-freedom (translational forces only) devices which are much more common. Third, I have developed a collaborative virtual sculpting paradigm to allow several users to simultaneously work on the same sculpture from different locations. This allows collaborative design without the requirement of being co-present. I will discuss methods for relaying the rapidly changing voxel and isosurface data between workstations, such that the local environment on each is synchronized in a manner that is immediate and transparent to the users. In addition, collisions between the different users' tools are felt through force-feedback. I implemented a collaborative haptic virtual sculpting simulation using the above methods in order to validate the system. The simulation was used to test the capabilities and limits of each contribution, as well as the real-time capability of the overall system. Ultimately this thesis demonstrates that it is possible to combine these technologies to form a flexible and intuitive collaborative virtual sculpting experience that operates in real-time.
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Badra, Fady. "Real-time immersive articulation of the human body in the WITS virtual training environment." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape11/PQDD_0028/MQ50589.pdf.
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Pons, Lelardeux Catherine. "Real-time virtual collaborative environment designed for risk management training : communication and decision making." Thesis, Toulouse 3, 2017. http://www.theses.fr/2017TOU30146/document.
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Les facteurs humains figurent parmi les causes originelles de trop nombreux accidents, dans les transports, l'industrie ou encore dans les parcours de soins. Dans ces contextes sociotechniques complexes et dynamiques, le risque de survenue d'incidents est permanent. La formation des équipes interprofessionnelles à la gestion des risques dans un environnement reproduisant fidèlement le contexte professionnel est un enjeu majeur. La motivation de cette thèse est de proposer un environnement virtuel multi-joueurs destiné à la formation à la gestion des risques liés à des défauts de communication ou de prises de décision. Pour cela, une méthode de création de scénarios interactifs destinés à la formation à la gestion des risques a été présentée. Un système de communication, un système collaboratif de prise de décision et un modèle de description d'objectifs complexes composés d'actions, de communications et de décisions sont présentés. L'environnement multi-joueurs interactif s'appuie sur cet ensemble cohérent. Ces systèmes et modèles proposés octroient une relative liberté aux équipes pour gérer la situation professionnelle présentée au sein de l'environnement virtuel. Ils permettent aussi le contrôle de la situation pédagogique dans son ensemble. Une méthode à forte valeur d'innovation a aussi été proposée pour structurer le débriefing d'une formation à la gestion des risques. Cela permet notamment d'automatiser la production de débriefing personnalisé, individuel et collectif à l'issu des séances de formationMany accidents in transport, industry or healthcare result from a causal chain of events where inadvertent human errors have not been corrected in time. In such socio-technical and dynamic systems where complexity and unpredictability widespread, training teams to risk management in real-life like situations is crucial. This thesis aims to provide a virtual multi-player environment designed for inter-professional team training to risk management. To that end, a method to design risk management interactive and controlled scenario has been described. A communication system, a group decision making system and a team tracing model have been created. They all together enable the virtual team to be free enough to manage the educational situations. These coherent and innovative environment allows us to control the team activity and automate the edition of a personalized, individual and corporate debriefing at the end of a team training session
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Schröder, Dirk [Verfasser]. "Physically based real-time auralization of interactive virtual environments / Dirk Schröder." Aachen : Hochschulbibliothek der Rheinisch-Westfälischen Technischen Hochschule Aachen, 2012. http://d-nb.info/1020247320/34.
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Haciomeroglu, Murat. "Populating virtual urban environments with crowds of pedestrians in real-time." Thesis, University of East Anglia, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.518360.
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Brownridge, Adam Mark. "Real-time motion capture for analysis and presentation within virtual environments." Thesis, Manchester Metropolitan University, 2014. http://e-space.mmu.ac.uk/326218/.
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This thesis describes motion capture methods with an application for real-time recording of extreme human movement. A wireless gyroscopic sensor based system is used to record and evaluate misalignments in ankle position of ballet dancers in a performance environment. Anatomic alignment has been shown to contribute to dance related injuries, and results of this work show that subtle variations in joint rotation can be clearly measured. The workflow has been developed to extract performance analysis data for fault detection in order to assist augmented feedback methods for the prevention of injury and improved performance. Infra-red depth sensing technology, commonly used in garment design, has been used to produce a representation of a scanned human subject and a workflow established to utilise this character avatar for animation using motion capture data. The process of presenting a visually acceptable representation of an overall performance in addition to the numerical evaluation of specific joint orientation provides a significant contribution to knowledge.
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Vatavu, Radu-Daniel. "Real-time acquisition of human gestures for interacting with virtual environments." Thesis, Lille 1, 2008. http://www.theses.fr/2008LIL10007/document.
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La thèse traite du problème de la reconnaissance des gestes avec des accents particuliers orientés vers la modélisation des trajectoires de mouvement ainsi que vers l’estimation de la variabilité présente dans l’exécution gestuelle. Les gestes sont acquis dans un scénario typique pour la vision par ordinateur qui approche les particularités des surfaces interactives. On propose un modèle flexible pour les commandes gestuelles à partir d’une représentation par courbes splines et des analogies avec des éléments de la théorie d’élasticité de la physique classique. On utilise les propriétés du modèle pour la reconnaissance des gestes dans un contexte d’apprentissage supervisé. Pour adresser le problème de la variation présente dans l’exécution des gestes, on propose un modèle qui mesure dans une manière quantitative et objective les tendances locales que les utilisateurs sont tentés d'introduire dans leurs exécutions. On utilise ce modèle pour proposer une solution à un problème reconnu comme difficile dans la communauté : la segmentation automatique des trajectoires continues de mouvement et l’identification invariante a l’échelle des commands gestuelles. On démontre aussi l’efficacité du modèle pour effectuer des analyses de type ergonomique pour les dictionnaires de gestesWe address in this thesis the problem of gesture recognition with specific focus on providing a flexible model for movement trajectories as well as for estimating the variation in execution that is inherently present when performing gestures. Gestures are captured in a computer vision scenario which approaches somewhat the specifics of interactive surfaces. We propose a flexible model for gesture commands based on a spline representation which is enhanced with elastic properties in a direct analogy with the theory of elasticity from classical physics. The model is further used for achieving gesture recognition in the context of supervised learning. In order to address the problem of variability in execution, we propose a model that measures objectively and quantitatively the local tendencies that users introduce in their executions. We make use of this model in order to address a problem that is considered hard by the community: automatic segmentation of continuous motion trajectories and scale invariant identification of gesture commands. We equally show the usefulness of our model for performing ergonomic analysis on gesture dictionaries
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Bharambe, Sachin Vasant. "Smart Environment Based On Real-Time Human Position Tracking For Remote Presence And Collaboration." Thesis, Virginia Tech, 2017. http://hdl.handle.net/10919/86661.
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Real-time, virtual and mixed reality systems have diverse uses for real-world data visualization, representation, and remote collaboration in distant learning settings, especially in universities. Design of such systems involves challenges in mapping the real world data and physical world structure accurately to digital form of physical space, also called as virtual models. Researchers have created similar systems using multiple cameras, stereo cameras, accelerometers, and motion detectors. This report presents a platform to detect and track real-time locations of people present in buildings and map their location information into virtual models as avatars using omni-directional cameras installed in the physical space. These models were created as part of the Mirror Worlds project. The project infrastructure is funded by National Science Foundation. This infrastructure enables users to connect virtual and physical aspects of the environment through a coordinate-based data networking system to enable interaction with the rest of the system including environment objects and other users. This is an interdisciplinary project where students from various departments have worked on the development of virtual model of the Moss Art Center and Torgersen Hall in Unity / X3D. Some students from the Department of Computer Science have developed a coordinate-based data networking system. The prototype of a detection and tracking algorithm to extract the location information was developed using background subtraction in MATLAB.
The proposed approach was developed using the combination of background subtraction and neural networks along with heuristics based on spatial information about the physical space. The system was scaled to work across multiple buildings, extract the location information of people present in the physical space, and map location information into shared virtual space as an avatar. The concept of remote presence was extended to create a collaborative object manipulation application using Leap Motion controller. Effects of fidelity were evaluated to perform the collaborative object manipulation task in shared virtual space based on user study conducted for this application.
Since no annotated people video dataset is publicly available with overhead view from omni-directional cameras, three videos were annotated manually to test the performance of the approach. The current approach almost works at near real-time rates. All three video sequences were evaluated to compute frame based detection accuracy. Precision and recall obtained for the first video sequence of people detection is 93.85% and 95.06% respectively.Master of Science
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Corbin, Daniel P. "NPSNET : environmental effects for a real-time virtual world battlefield simulator /." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 1993. http://handle.dtic.mil/100.2/ADA275032.
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Zhou, Wei. "An investigation into a distributed virtual reality environment for real-time collaborative 4D construction planning and simulation." Thesis, University of Wolverhampton, 2009. http://hdl.handle.net/2436/98506.
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The use and application of 4 Dimensional Computer Aided Design (4D CAD) is growing within the construction industry. 4D approaches have been the focus of many research efforts within the last decade and several commercial tools now exist for the creation of construction simulations using 4D approaches. However, there are several key limitations to the current approaches. For example, 4D models are normally developed after the initial planning of a project has taken place using more traditional techniques such as Critical Path Method (CPM). Furthermore, mainstream methodologies for planning are based on individual facets of the construction process developed by discrete contractors or sub-contractors. Any 4D models generated from these data are often used to verify work flows and identify problems that may arise, either in terms of work methods or sequencing issues. Subsequently, it is perceived that current 4D CAD approaches provide a planning review mechanism rather than a platform for a novel integrated approach to construction planning. The work undertaken in this study seeks to address these issues through the application of a distributed virtual reality (VR) environment for collaborative 4D based construction planning. The key advances lie in catering for geographically dispersed planning by discrete construction teams. By leveraging networked 4D-VR based technologies, multidisciplinary planners, in different places, can be connected to collaboratively perform planning and create an integrated and robust construction schedule leading to a complete 4D CAD simulation. Establishing such a complex environment faces both technological and social challenges. Technological challenges arise from the integration of traditional and recent 4D approaches for construction planning with an ad hoc application platform of VR linked through networked computing. Social challenges arise from social dynamics and human behaviours when utilizing VR-based applications for collaborative work. An appropriate 4D-based planning method in a networked VR based environment is the key to gaining a technical advancement and this approach to distributed collaborative planning tends to promote computer-supported collaborative work (CSCW). Subsequently, probing suitable CSCW design and user interface/interaction (UI) design are imperative for solutions to achieve successful applicability. Based on the foregoing, this study developed a novel robust 4D planning approach for networked construction planning. The new method of interactive definition was devised through theoretical analysis of human-computer interaction (HCI) studies, a comparison of existing 4D CAD creation, and 3D model based construction planning. It was created to support not only individual planners’ work but multidisciplinary planners’ collaboration, and lead to interactive and dynamic development of a 4D simulation. From a social perspective, the method clarified and highlighted relevant CSCW design to enhance collaboration. Applying this rationale, the study specified and implemented a distributed groupware solution for collaborative 4D construction planning. Based on a developed system architecture, application mode and dataflow, as well as a real-time data exchange protocol, a prototype system entitled ‘4DX’ was implemented which provides a platform for distributed multidisciplinary planners to perform real-time collaborative 4D construction planning. The implemented toolkit targeted a semi-immersive VR platform for enhanced usability with compatibility of desktop VR. For the purpose of obtaining optimal UI design of this kind of VR solution, the research implemented a new user-centred design (UCD) framework of Taguchi-Compliant User-Centred Design (TC-UCD) by adapting and adopting the Taguchi philosophy and current UCD framework. As a result, a series of UIs of the VR-based solution for multifactor usability evaluation and optimization were developed leading to a VR-based solution with optimal UIs. The final distributed VR solution was validated in a truly geographically dispersed condition. Findings from the verification testing, the validation, and the feedback from construction professionals proved positive in addition to providing constructive suggestions to further reinforce the applicability of the approach in the future.
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Däumler, Martin. "Real-time Code Generation in Virtualizing Runtime Environments." Doctoral thesis, Universitätsbibliothek Chemnitz, 2015. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-qucosa-162075.
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Modern general purpose programming languages like Java or C# provide a rich feature set and a higher degree of abstraction than conventional real-time programming languages like C/C++ or Ada. Applications developed with these modern languages are typically deployed via platform independent intermediate code. The intermediate code is typically executed by a virtualizing runtime environment. This allows for a high portability. Prominent examples are the Dalvik Virtual Machine of the Android operating system, the Java Virtual Machine as well as Microsoft .NET’s Common Language Runtime. The virtualizing runtime environment executes the instructions of the intermediate code. This introduces additional challenges to real-time software development. One issue is the transformation of the intermediate code instructions to native code instructions. If this transformation interferes with the execution of the real-time application, this might introduce jitter to its execution times. This can degrade the quality of soft real-time systems like augmented reality applications on mobile devices, but can lead to severe problems in hard real-time applications that have strict timing requirements. This thesis examines the possibility to overcome timing issues with intermediate code execution in virtualizing runtime environments. It addresses real-time suitable generation of native code from intermediate code in particular. In order to preserve the advantages of modern programming languages over conventional ones, the solution has to adhere to the following main requirements:
- Intermediate code transformation does not interfere with application execution
- Portability is not reduced and code transformation is still transparent to a programmer
- Comparable performance
Existing approaches are evaluated. A concept for real-time suitable code generation is developed. The concept bases on a pre-allocation of the native code and the elimination of indirect references, while considering and optimizing startup time of an application. This concept is implemented by the extension of an existing virtualizing runtime environment, which does not target real-time systems per se. It is evaluated qualitatively and quantitatively. A comparison of the new concept to existing approaches reveals high execution time determinism and good performance and while preserving the portability deployment of applications via intermediate code.
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Waldrop, Marianne Susan. "Real-time articulation of the upper body for simulated humans in virtual environments." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 1995. http://edocs.nps.edu/npspubs/scholarly/theses/1995/Sep/95Sep_Waldrop.pdf.
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McDermott, Scott. "An Analysis of Accurate, Real-Time Reproduction of 3D Acoustics in Virtual Environments." Thesis, University of Louisiana at Lafayette, 2015. http://pqdtopen.proquest.com/#viewpdf?dispub=3687696.
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Many of the applications, virtual environments, and video games available to average computer users integrate stunning three-dimensional (3D) graphics and real-world visualizations. Developers spend an extraordinary amount of time and effort creating these immersive, realistic virtual environments, primarily focusing on the graphics components. Within these virtual realities, the user should easily perceive the locations of sound sources accurately, as well as the acoustic nature of the environment. However, for reasons of economy and simplicity, most developers apply readily available industry standards for generating pseudo-3D sounds in their applications. This research explores the shortcomings of these standards, proposes an effective alternative, and provides a detailed analysis of the various possible approaches.
This project includes a number of computationally efficient, physics-based 3D acoustics simulations, each of which will produce realistic aural reproductions. The primary goal is to evaluate and compare these algorithms against each other, non-3D sound reproduction, and the current industry standards (e.g. Microsoft's DirectX® pseudo-3D algorithm). We will test three hypotheses. First, users will find that physics-based 3D algorithms will render improved auralization reproductions compared against industry standards like DirectX® and/or OpenAL. Second, localization and spatialization will improve with user training when using these algorithms. Finally, we should discover an unambiguous ranking system for the quality of each tested algorithm.
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Talvas, Anthony. "Bimanual haptic interaction with virtual environments." Thesis, Rennes, INSA, 2014. http://www.theses.fr/2014ISAR0015/document.
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En Réalité Virtuelle (RV), le sens haptique accroît l’immersion d’un utilisateur dans un Environnement Virtuel (EV) avec lequel il interagit en temps réel. Dans cette thèse, nous proposons des approches pour améliorer l’interaction haptique à deux mains avec des EV. Nous abordons d’abord des problèmes avec l’interaction bimanuelle dans des EV avec des interfaces à effecteur unique. Nous proposons une technique d’interaction nommée la double bulle pour l’exploration d’EV avec une combinaison de contrôle en position et en vitesse. Nous présentons aussi une technique de manipulation nommée prise magnétique qui facilite la saisie d’objets virtuels avec des proxys rigides simples. Des modes de contrôle communs sont utilisés pour améliorer la saisie et l’exploration simultanées. Une évaluation utilisateur a été réalisée pour mesurer l’efficacité de ces techniques. Nous nous intéressons ensuite au calcul de surfaces de contact. Nous proposons une technique nommée god-finger pour rendre des surfaces similaires à celles générées par des doigts à partir d’un unique point de contact. Elle est basée sur un simple parcours de la géométrie locale de l’objet en contact, et est donc moins coûteuse que des méthodes de simulation de corps souples. La méthode est adaptée pour l’interaction avec des proxys rigides simples ou plus complexes, ainsi qu’avec des objets rigides ou déformables, y compris avec des surfaces rugueuses. Une méthode de rendu visuel donne un retour à l’utilisateur sur la forme de la surface de contact. Enfin, nous abordons la résolution de contacts durant la manipulation dextre d’objets virtuels avec des doigts souples. Le calcul des mécaniques de contact est amélioré en agrégeant les multiples contraintes de contact concernées. Une méthode de distribution de pression non uniforme sur la surface de contact adapte la réponse lors d’un contact contre des arêtes pointues. Nous utilisons le modèle de frottement de Coulomb- Contensou pour simuler efficacement le frottement en torsion. L’approche est évaluée avec un modèle de main déformable pour de l’interaction en temps réel. Les travaux présentés dans ce manuscrit ouvrent de nouvelles perspectives dans le contexte de l’haptique bimanuelle et de la RV, en permettant une interaction plus naturelle avec des EV plus complexesIn Virtual Reality (VR), the haptic sense increases the immersion of users in a Virtual Environment (VE) with which they interact in real time. In this Ph.D thesis, we propose contributions to improve two-handed interaction in haptics with VEs. We first address issues with bimanual interaction in VEs using haptic devices with single effectors. We propose an interaction technique called double bubble for exploration of VEs through a combination of position and rate control. We also present a manipulation technique called magnetic pinch which facilitates the grasping of virtual objects with simple rigid proxies. Simultaneous grasping and exploration of the VE is enhanced using common control modes. A user evaluation was conducted to assess the efficiency of these techniques. We then focus on improving the computation of contact surfaces. We propose a god-finger method to render finger padlike surfaces from a single contact point. It relies on a simple scan of the local geometry of the object in contact, and is this less costly than soft body simulation methods. The method is adapted for interaction using simple or more complex rigid virtual proxies, and with rigid or deformable objects, including rough surfaces. A visual rendering method provides feedback on the shape of the contact surface. Finally, we address the resolution of contacts during dexterous manipulation of virtual objects through soft fingers. The computation of contact mechanics is improved by aggregating the multiple contact constraints involved. A method for nonuniform pressure distribution over the contact surface adapts the response when touching sharp edges. We use the Coulomb-Contensou friction model to efficiently simulate torsional friction. The approach is evaluated with a deformable hand model for real time interaction. The contributions of this manuscript open novel perspectives in the context of bimanual haptics and VR, allowing more natural interaction with more complex VEs
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Moreau, Filip. "Physics-Based, Real-Time Simulation of Fluid-Immersed Rigid Bodies." Thesis, Malmö universitet, Fakulteten för teknik och samhälle (TS), 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:mau:diva-43343.
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Objects interacting with fluid are of high interest to visually present in three-dimensional applications, such as computer games and virtual environments. For presenting the interactions with high correctness, dynamic rigid body simulation may be used. This paper presents methods for efficient, physics-based real-time simulation of fluid-immersed rigid bodies, where the correctness of the simulation is maintained. Simulated forces include gravity, buoyancy, thrust, drag, and lift. To have the simulation run efficiently in real-time, discretization of the simulated rigid body is made by applying mentioned forces to a user-defined number of particles, sampled pseudo-randomly within the rigid body.
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English, Joel Alexander. "Assessing the synchronous online classroom : methodologies and findings in real-time virtual learning environments." Virtual Press, 1999. http://liblink.bsu.edu/uhtbin/catkey/1137523.
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In "Technology and Literacy: A Story about the Perils of Not Paying Attention," Cynthia Selfe charges the field of composition not to simply consider technology a tool, but to "pay attention" to the rhetorical and social implications of those tools. In one sense, paying critical attention to technological literacies echoes the decade-old call for Computers and Writing practitioners to use research as a means of assessing online activities, suggesting that teachers not remain satisfied with the unreflective excitement that has been the operative epistemology of the field from its beginning. In another sense, Selfe's recent call enlists teachers and students in reflective and evaluative class discussion and writing on the technological literacy tools they are learning to use.This dissertation responds to both of these implications as it studies a semester of first-year college composition students within a synchronous online classroom environment. The question that guides my study is, in its most basic form, what happens during synchronous online writing conferences? And to speak to that question, I design an ethnographic context-sensitive text analysis employing grounded theory for data coding, a methodological model adaptable for future research in synchronous online classroom activity. I focus on three issues that have continually arisen in the scholarship surrounding synchronous conferencing: aspects of online language, the implications of the environment within object-oriented MUDs (MOOs), and the use of social constructionism as a theoretical foundation for synchronous conferencing.With the findings from my study, I conclude the dissertation by offering pedagogical suggestions to teachers and students for critically assessing synchronous online discourse. My articulation of assessment mandates that students and teachers engage in it together, collaboratively reflecting on what happens online and learning about synchronous online discourse-a significant ingredient in contemporary literacy.Department of English
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Anderson, Eike F. "On the definition of non-player character behaviour for real-time simulated virtual environments." Thesis, Bournemouth University, 2008. http://eprints.bournemouth.ac.uk/11991/.
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Computer games with complex virtual worlds, which are populated by artificial characters and creatures, are the most visible application of artificial intelligence techniques. In recent years game development has been fuelled by dramatic advances in computer graphics hardware which have led to a rise in the quality of real-time computer graphics and increased realism in computer games. As a result of these developments video games are gaining acceptance and cultural significance as a form of art and popular culture. An important factor for the attainment of realism in games is the artificially intelligent behaviour displayed by the virtual entities that populate the games' virtual worlds. It is our firm belief that to further improve the behaviour of virtual entities, game AI development will have to mirror the advances achieved in game graphics. A major contributing factor for these advancements has been the advent of programmable shaders for real-time graphics, which in turn has been significantly simplified by the introduction of higher level programming languages for the creation of shaders. This has demonstrated that a good system can be vastly improved by the addition of a programming language. This thesis presents a similar (syntactic) approach to the definition of the behaviour of virtual entities in computer games. We introduce the term behaviour definition language (BDL), describing a programming language for the definition of game entity behaviour. We specify the requirements for this type of programming language, which are applied to the development and implementation of several behaviour definition languages, culminating in the design of a new game-genre independent behaviour definition (scripting) language. This extension programming language includes several game AI techniques within a single unified system, allowing the use of different methods of behaviour definition. A subset of the language (itself a BDL) was implemented as a proof of concept of this design, providing a framework for the syntactic definition of the behaviour of virtual entities in computer games.
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Ramaraj, Sharath. "Supporting Quality of Service in Distributed Virtual Environments." Thesis, Virginia Tech, 2003. http://hdl.handle.net/10919/35401.
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We present a resource allocation perspective to Quality of Service in Distributed Virtual
Environments. The user of a DVE system will have improved Quality of Service if he/she
is allocated the right amount of resources at the right time. Instead of allocating resources
on a static basis, we adopt a dynamic need based resource allocation scheme that provides real-time resource allocation. Optimal resource assignments are calculated o2ine and a neural network is trained with the knowledge of optimal solutions from the o2ine Operations Research Techniques and it is then used to deliver near-optimal resource allocation decisions in real-time. We also present a case study of network bandwidth allocation and prove the usefulness of the technique.Master of Science
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Whiting, Jennifer Kay. "Development of a Real-Time Auralization System for Assessment of Vocal Effort in Virtual-Acoustic Environments." BYU ScholarsArchive, 2018. https://scholarsarchive.byu.edu/etd/7056.
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This thesis describes the development of the real-time convolution system (RTCS) for a little-studied talker/listener in virtual acoustic environments. We include descriptions of the high-resolution directivity measurements of human speech, the RTCS system components, the measurement and characterization of oral-binaural room impulse responses (OBRIRs) for a variety of acoustic environments, and the compensation filter necessary for its validity. In addition to incorporating the high-resolution directivity measurements, this RTCS improved on that developed by Cabrera et al. [1] through the derivation and inclusion of the compensation filter. Objective measures in the time- and frequency-domains, as well as subjective measures, were developed to asses the validity of the RTCS. The utility of the RTCS is demonstrated in the study on vocal effort, and the results of an initial investigation into the vocal effort data are presented.
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Abdellatif, Reham Mahmoud Ahmed. "Design reviews at a distance : a qualitative analysis of mediated interaction in 3D real-time virtual environments." Thesis, University of Newcastle upon Tyne, 2012. http://hdl.handle.net/10443/1603.
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The use of new media such as massively multi-user 3D virtual environments; ‘virtual worlds’, in design learning is directed by expectations that they have the potential to simulate human characteristics via Avatars. The three dimensional spatial and communicational properties afforded by this virtual environment provide an opportunity to distantly interact, visualise and keep records of the students’ design reviews, while reducing the levels of tension, defence and shyness experienced by some students in traditional face-to-face design reviews. This thesis proposes that despite these potentials for a successful interactional medium, properties of mediation, virtuality and remoteness of mediated design reviews affect how learning interactions are communicated and delivered; changing the overall learning experience, and thus its effectiveness. In order to determine the effectiveness of the mediated learning interaction process in 3D virtual worlds, this research performs a protocol analysis study where it proposes an assessment framework that examines indicators of effectiveness of three constituting processes; communication efficiency, learning effectiveness and learner-technology interaction. The study hypothesises that the availability and limitation of certain communication modes afforded by the virtual environment may affect the flow and sequences of synchronous communication, but not necessarily the quality and content of mutually communicated information. It proposes that certain properties of the technology, specifically those which aim to support different forms of interaction, such as embodiment, presence and remoteness will play a positive role in the effectiveness of the learning interaction process. This thesis hypothesises as well that students and tutors will continue to interact effectively and create a shared language of communication despite some communicational challenges. To test these hypotheses and examine the effectiveness of the learning interaction process, this thesis adopts an exploratory methodology. Varying in the degree of mediation, three categories of small size design review groups of students and tutors were conducted and closely observed. A coding scheme specific to the design review protocol was designed and developed in this thesis based on observations of the first category; face-to-face design reviews. Two other virtual reviews performed at two degrees of mediation/remoteness, allowed us to explore mediated interactions ‘within’ the 3D virtual world and ‘with’ the physical computer. Qualitatively-based interaction and content analyses of the recorded activities, in addition to questionnaires and focus groups with the participants, provided evidence that there are noticeable differences in both; verbal content and nonverbal interactions between the three design review categories, hence variations in learning effectiveness. It was found that not only the availability or restriction of certain communication modes that had caused these differences, but the way the users used, adopted and perceived the virtual properties of the medium, had played a significant role as well. It is hoped that the method developed in this thesis can shed more light upon the neglected communicational aspects of final design reviews and come closer to enhance the delivery of learning in the design studio. It is hoped as well that this research can inform the literature on virtual worlds as online-learning environments in design-based disciplines, by probing deeper than simply accepting or rejecting the use of the technology, but rather to analyse the properties they afford or deny within context. Furthermore, it is hoped that the recommendations of this research be employable to aid virtual world and Avatar designers to develop interactional aspects of virtual worlds to be considered for a wider range of more complicated interaction processes such as the architectural design review.
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Dutton, James Allen. "Developing articulated human models from laser scan data for use as avatars in real time networked virtual environments." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2001. http://handle.dtic.mil/100.2/ADA397086.
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Thesis (M.S. in Modeling, Virtual Environments, and Simulation)--Naval Postgraduate School, Sept. 2001.Thesis advisors: Bachmann, Eric ; Yun, Xiaoping. "September 2001." Includes bibliographical references (p. 47-49). Also Available online.
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Runebjörk, Daniel. "Evaluering av kontextmodeller och interaktiva virtuella miljöer i den arkitektoniska gestaltningsprocessen." Thesis, Luleå tekniska universitet, Arkitektur och vatten, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-78641.
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The tools available to architects in the design process are constantly being enhanced and developed, which paves the way to try out new methods and techniques. The current widespread availability of commercial drones, sophisticated surveying instruments and advanced calculation software, makes it possible to create detailed digital representations of reality, in the form of context models. Context models in combination with real-time rendering, through game engines and visualization with the help of Interactive Virtual Environments (IVE), lets architects recreate planned buildings in a realistic virtual context. The study examines how the architect can leverage the benefits of context models and IVE in the architectural design process and presents a method which can be used by architect- and consultant firms. A qualitative research method is used to accomplish this goal, where data is gathered through interviews and a workshop with practicing architects, but also a case study is performed to evaluate the presented method. All the collected data is compartmentalized and analyzed with a method called Pattern Matching, where expected theoretical patterns are compared to the empirical data that appear from the collected data. The study shows that the use of context models and IVE has great benefits in several varying phases of the design process, where benefits in communication is presented as the main contributing factor. With that said, there are concerns regarding implementation of the tools in early stages of the design process, where the possibility to present a misleading IVE is regarded as a potential risk. A presented benefit of using context models and IVE is the ability to create virtual presence. Also, the ability to present the building in its real context proved to be a great benefit in the study. These are closely tied to the benefits of IVR (Immersive Virtual Reality), in cases where visualization of volumes and spaces is needed, which is enhanced by a detailed context model. Finally, a method for architects and consultants to use context models and IVE in the design process is presented. The method is summarized to involve different expertise in the organization to carry through different tasks in the workflow, in order to let the architect focus on the design of the building, but still leverage the benefits of the visualization tools. A conclusion that is drawn, is that the presented method needs to be evaluated further, in order to prove its efficiency. If that is the case, the method might be a step in a new path for the ever changing role of the architect.Verktygen som är tillgängliga för en arkitekt under gestaltningsprocessen utvecklas konstant, vilket banar väg för att testa nya arbetsmetoder och tekniker. Den numera breda tillgängligheten till kommersiella drönare, sofistikerade mätinstrument och avancerade beräkningsprogram gör det möjligt att på smidiga sätt framställa detaljerade digitala verklighetsrepresentationer, i form av kontextmodeller. Tillsammans med realtidsrendering, genom spelmotorer och visualisering med hjälp av interaktiva virtuella miljöer (Interactive Virtual Environements, IVE), kan arkitekter idag återskapa planerade byggnader i en verklighetstrogen virtuell kontext. Studien tittar på hur arkitekten kan dra nytta av kontextmodeller och IVE i gestaltningsprocessen och presenterar en arbetsmetod som kan tillämpas av arkitekt – och teknikkonsultbyråer. För att uppnå detta tillämpas en kvalitativ forskningsmetod, där data samlas in genom intervjuer och workshop tillsammans med arkitekter och en praktisk tillämpning i form av en fallstudie. All samlade data sammanställs och analyseras med en så kalla mönstermatchning (eng. Pattern Matching), där förväntade teoretiska mönster jämförs med de empiriska mönster som träder fram ur datamängden. Studien visar att användning av kontextmodeller och IVE har stora fördelar i flera olika skeden av gestaltningsprocessen, där främst kommunikationsvinster presenteras som en huvudsaklig bidragande faktor. Däremot råder viss oro för implementering av tekniken i allt för tidiga skeden och även risker med att presentera förvirrande och missvisande IVE lyfts fram som en risk. En fördel som presenteras är kontextmodellers och IVEs förmåga att skapa virtuell närvaro, men också möjligheten att presentera en byggnads omgivning virtuellt, presenterades som en stor vinst i studien. Detta är starkt kopplat till fördelarna som IVR (Immersive Virtual Reality) bidrar med, i frågor om att visualisera volymer och rumsligheter, något som förstärks av en detaljerad kontextmodell. Slutligen presenteras en arbetsmetod för hur teknikkonsulter och arkitekter kan tillämpa kontextmodeller och IVE under gestaltningsprocessen. Arbetsmetoden sammanfattas till att enskilda kompetensområden med fördel utför olika delar av processen, vilket tillåter arkitekten att fokusera på gestaltningsarbetet, men samtidigt dra nytta av visualiseringsteknikerna. En slutsats som dras är att den framtagna arbetsmetoden måste förankras i verkligheten, genom att tillämpas i ett verkligt projekt innan den kan bevisas som effektiv. Om den i framtiden bevisas effektiv kan arbetsmetoden visas vara ett steg i ny riktning för ett skiftande arbetssätt inom arkitektyrket.
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Trignano, Vincenzo. "Virtual prototyping of embedded real-time systems." Thesis, University of Sussex, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.414786.
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This thesis presents the ViPERS (Virtual Prototyping of Embedded Real-time Systems) virtual prototyping methodology. The concepts, the implementation, and the experiments presented in this thesis were developed at the University of Sussex (UoS) in the Centre for VLSI and Computer Graphics and were part of an EU funded project. ViPERS refers to a design methodology which links the graphical and interactive features of virtual prototyping techniques with key design trends for SoCs. System level design is a widely adopted approach to deal with the complexity, short time-to-market, and heterogeneous nature of today's electronic systems. The integration of virtual prototyping with the SystemC design methodology is proposed to deal with issues such as the modelling of the interfaces and the exploration of user-machine interaction which are becoming of vital importance in embedded handheld devices. An exploration of virtual prototyping and SOC design is illustrated in the thesis to provide an understanding of the objectives of the ViPERS methodology. The ViPERS approach is assisted by a framework which provides the necessary tools needed for the implementation and simulation of virtual prototypes in the different phases of the suggested design flow. After illustrating the ViPERS methodology and environment the focus of this thesis will be on the links provided within the ViPERS framework to allow communication between the graphical models and the underlying functional counterparts. A key contribution includes the development of a design flow for SoCs, with special focus on the communication infrastructure which enables the graphical and functional models to interact at simulation time. Another contribution in this thesis is the illustrative case study where interactive photorealistic models of electronic handheld devices are combined with their respective functional models implemented in SystemC and UML. The case study presents the design of an RF-based remote control for home automation.
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Terrasa, Barrena Andrés Martín. "Flexible Real-Time Linux a New Environment for Flexible Hard Real-Time Systems." Doctoral thesis, Universitat Politècnica de València, 2012. http://hdl.handle.net/10251/18060.
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[ES] La presente tesis propone un nuevo entorno general para la construcción de sistemas flexibles de tiempo real estricto, esto es, sistemas que necesitan de garantías de tiempo real estricto y de un comportamiento flexible. El entorno propuesto es capaz de integrar tareas con varios niveles de criticidad y diferentes paradigmas de planificación en el mismo sistema. Como resultado, el entorno permite proporcionar garantías de tiempo real estricto a las tareas críticas y además conseguir una planificación adaptativa e inteligente de las tareas menos críticas. El entorno se define en términos de un modelo de tareas, una arquitectura software y un conjunto de servicios. El modelo de tareas propone construir una aplicación flexible de tiempo real estricto como un conjunto de tareas, donde cada tarea se estructura en una secuencia de componentes obligatorios y opcionales. La arquitectura software propone separar la ejecución de las tareas en dos niveles de planificación interrelacionados, de manera que un nivel planifica los componentes obligatorios mediante una política de planificación de tiempo real estricto mientras que el otro nivel planifica los componentes opcionales mediante una política de planificación basada en la utilidad. El conjunto de servicios incluye, por una parte, un sistema de comunicación entre los componentes de las tareas (tanto obligatorios como opcionales) y, por otra, una serie de mecanismos para la detección y tratamiento de excepciones temporales producidas en ejecución.
Por otra parte, la presente tesis muestra que el entorno teórico propuesto puede ser implementado realmente. En concreto, se presenta el diseño e implementación de un sistema de ejecución (es decir, un núcleo de sistema operativo) capaz de soportar las características de dicho entorno. Este sistema, denominado Flexible Real-Time Linux (FRTL), ha sido desarrollado a partir de un núcleo mínimo existente denominado Real-Time Linux (RT-Linux).
Finalmente, esta tesis presenta una caracterización temporal completa del sistema FRTL y medidas reales de su sobrecarga. La caracterización temporal ha permitido el desarrollo de un test de garantía completo de todo el sistema (incluyendo la aplicación y el núcleo de FRTL), que puede ser utilizado para verificar las restricciones temporales de cualquier aplicación implementada sobre FRTL. Por su parte, las medidas de la sobrecarga de FRTL muestran que este núcleo ha sido diseñado e implementado de manera eficiente. En conjunto, se demuestra que el núcleo FRTL es a la vez predecible y eficiente, dos características que informan de su utilidad en la implementación real de aplicaciones flexibles de tiempo real estricto.[CA] Aquesta tesi proposa un nou entorn general per a la construcció de sistemes flexibles de temps real estricte, això és, sistemes que requereixen garanties de temps real estricte i un comportament flexible. L'entorn proposat és capaç d'integrar tasques amb diferentsnivells de criticitat i diferents paradigmes de planificació al mateix sistema. Com a resultat, l'entorn permet proporcionar garanties detemps real estricte a les tasques crítiques i a més aconseguir una planificació adaptativa i intel¿ligent de les tasques menys crítiques. L'entorn es defineix en termes d'un model de tasques, una arquitectura software i un conjunt de serveis. El model de tasques proposa la construcció d'una aplicació flexible de temps real estricte com a un conjunt de tasques on cadascuna és estructurada com una seqüència de components obligatòries i opcionals. L'arquitectura software proposa la separació de l'execució de les tasques en dos nivells de planificació interrelacionats, de manera que un nivel planifica les components obligatòries mitjançant una política de planificació de temps real estricte mentre que l'altre nivell planifica les components opcionals mitjançant una política de planificació basada en la utilitat. El conjunt de serveis inclou, per una part, un sistema de comunicació entre les components de les tasques (tant obligatòries com opcionals) i, per una altra, una sèrie de mecanismes per a la detecció i tractament d'excepcions temporals produïdes en execució. Per altra banda, la present tesi mostra que el proposat entorn teòric pot ésser implementat realment. En concret, es presenta el diseny i la implementació d'un sistema d'execució (es a dir, un nucli de sistema operatiu) capaç de suportar les característiques d'aquest entorn. Aquest sistema, anomenat Flexible Real-Time Linux (FRTL), ha sigut desenvolupat a partir d'un nucli mínim existent anomenat Real-Time Linux (RT-Linux). Finalment, aquesta tesi presenta una caracterització temporal completa del sistema FRTL i mesures reals de la seua sobrecàrrega. La caracterització temporal ha permés el desenvolupament d'un test de garantia complet de tot el sistema (incloent l'aplicació i el nucli FRTL), que pot ésser utilitzat per a verificar les restriccions temporals de qualsevol aplicació implementada sobre FRTL. Per la seua part, les mesures de la sobrecàrrega de FRTL mostren que aquest nucli ha sigut disenyat i implementat de manera eficient. En conjunt, es demostra que el nucli FRTL és al mateix temps predible i eficient, dos característiques que informen de la seua utilitat a la implementació real d'aplicacions flexibles de temps real estricte.
Terrasa Barrena, AM. (2001). Flexible Real-Time Linux a New Environment for Flexible Hard Real-Time Systems [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/18060
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Dahlman, Gustav, and Johan Omara. "Real time location system for indoor environment." Thesis, Malmö universitet, Fakulteten för teknik och samhälle (TS), 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:mau:diva-20092.
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Fältet inomhuspositionering är en viktig och stor front och är i fortsatt och snabb utveckling inom IoT-teknik och digitalisering av storstäder. Detta arbete är utformat för att hitta och byggaen lämplig teknik för att komprimera olinjäriteter från multipatutbredning. I denna uppsats undersöks olika lokaliseringstekniker och metoder genom en litteraturstudie. Baserat på resultatetav litteraturstudien och en given uppsättning krav designas och implementeras en prototyp. Detresulterande systemet är baserat på UWB-teknik med hjälp av TWR, trilateration och ett kalmanfilter. Prototypen testas i olika miljöer. Resultaten visar att systemet kan detektera taggen i LOSförhållanden samt klara av visa NLOS förhållanden med en noggrannhet på mindre än 1m respektive 4m. Dessa tester inkluderar både distans mätning (1D) och position mätning i ett plan (2D).Dessutom diskuteras en del om hur man ökar prototypens prestanda.The field of indoor positioning is an important front and in fast and rapid development as therise of IoT and digitization of big cities. This work is designed to find and build an appropriatetechnology to compact nonlinearities from multipath propagation. In this paper various availablelocalization-technologies and methods are examined through a literature study. Based on the resultof the literature study and a given set of requirements, a prototype is designed and implemented.The resulting system is based on UWB technology using TWR, trilateration and a kalman filter.The prototype is tested in various different environments. The results show that the system is ableto successfully locate an object while fulfilling the requirements of this work. Additionally, someideas on how to increase the performance of the prototype is discussed.
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Ong, Henry Tong. "Physical based toolkit for real-time distributed virtual world." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 1995. http://handle.dtic.mil/100.2/ADA303720.
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Mathiason, Gunnar. "Virtual Full Replication for Scalable Distributed Real-Time Databases." Doctoral thesis, Linköpings universitet, Institutionen för datavetenskap, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-20661.
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A fully replicated distributed real-time database provides high availability and predictable access times, independent of user location, since all the data is available at each node. However, full replication requires that all updates are replicated to every node, resulting in exponential growth of bandwidth and processing demands with the number of nodes and objects added. To eliminate this scalability problem, while retaining the advantages of full replication, this thesis explores Virtual Full Replication (ViFuR); a technique that gives database users a perception of using a fully replicated database while only replicating a subset of the data. We use ViFuR in a distributed main memory real-time database where timely transaction execution is required. ViFuR enables scalability by replicating only data used at the local nodes. Also, ViFuR enables flexibility by adaptively replicating the currently used data, effectively providing logical availability of all data objects. Hence, ViFuR substantially reduces the problem of non-scalable resource usage of full replication, while allowing timely execution and access to arbitrary data objects. In the thesis we pursue ViFuR by exploring the use of database segmentation. We give a scheme (ViFuR-S) for static segmentation of the database prior to execution, where access patterns are known a priori. We also give an adaptive scheme (ViFuR-A) that changes segmentation during execution to meet the evolving needs of database users. Further, we apply an extended approach of adaptive segmentation (ViFuR-ASN) in a wireless sensor network - a typical dynamic large-scale and resource-constrained environment. We use up to several hundreds of nodes and thousands of objects per node, and apply a typical periodic transaction workload with operation modes where the used data set changes dynamically. We show that when replacing full replication with ViFuR, resource usage scales linearly with the required number of concurrent replicas, rather than exponentially with the system size.
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Cai, Hao. "A virtual machine for high integrity real-time systems." Thesis, University of York, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.425411.
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Robb, Michael Stuart Alexander. "Interactive real-time three-dimensional visualisation of virtual textiles." Thesis, Heriot-Watt University, 2009. http://hdl.handle.net/10399/2310.
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Virtual textile databases provide a cost-efficient alternative to the use of existing hardcover sample catalogues. By taking advantage of the high performance features offered by the latest generation of programmable graphics accelerator boards, it is possible to combine photometric stereo methods with 3D visualisation methods to implement a virtual textile database. In this thesis, we investigate and combine rotation invariant texture retrieval with interactive visualisation techniques. We use a 3D surface representation that is a generic data representation that allows us to combine real-time interactive 3D visualisation methods with present day texture retrieval methods. We begin by investigating the most suitable data format for the 3D surface representation and identify relief-mapping combined with Bézier surfaces as the most suitable 3D surface representations for our needs, and go on to describe how these representation can be combined for real-time rendering. We then investigate ten different methods of implementing rotation invariant texture retrieval using feature vectors. These results show that first order statistics in the form of histogram data are very effective for discriminating colour albedo information, while rotation invariant gradient maps are effective for distinguishing between different types of micro-geometry using either first or second order statistics.
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Aquotte, Fabio de Almeida. "Real-time diffuse indirect illumination with virtual light meshes." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2017. http://hdl.handle.net/10183/164054.
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A iluminação indireta é capaz de elevar consideravelmente a qualidade visual de cenas renderizadas, mas é também uma operação custosa. Por este motivo, há muito esforço de pesquisa voltado para a renderização de iluminação indireta em tempo real. Apesar de atualmente existirem técnicas poderosas para a iluminação indireta em tempo real, elas fornecem ao artista apenas um controle grosseiro do equilíbrio entre qualidade e desempenho. Nós propomos uma Malha de Luzes Virtuais para calcular a iluminação indireta difusa numa cena, inspirados pelo uso de outras malhas auxiliares, como Malhas de Navegação e Malhas de Colisão. Uma Malha de Luzes Virtuais (MLV) é uma malha simplificada de luzes poligonais usadas para aproximar a luz refletida pela geometria real. Juntamente com a MLV, nós projetamos uma estrutura de dados de aceleração para atingir um desempenho eficiente com iluminação indireta usando uma MLV complexa. O uso da MLV apresenta algumas características vantajosas: maior controle artístico dos atributos da iluminação indireta; a possibilidade de integração com técnicas existentes como animação esquelética e geração procedural; e integração simples com ferramentas e processos de produção de arte existentes. Nossos resultados experimentais mostram que a iluminação indireta controlada por artistas é uma alternativa viável a métodos existentes.Indirect illumination on a rendered scene can add a great deal to its visual quality, but it is also a costly operation. Therefore, a lot of research targets how to render indirect illumination in real-time. While powerful techniques for real-time indirect illumination currently exist, they provide only coarse-grained artistic control over the trade-off between quality and speed. We propose a Virtual Light Mesh to compute the scene’s diffuse indirect illumination, inspired by the use of other current auxiliary meshes such as Navigation Meshes and Collision Meshes. A Virtual Light Mesh (VLM) is a simplified mesh of polygonal lights used to approximate the light bounced by the real geometry. Together with the VLM, we design an acceleration data structure for efficient indirect illumination performance with a complex VLM. The use of VLM presents some positive properties: greater artistic control of the indirect illumination characteristics; the possibility of integration with existing techniques such as skeletal animation and procedural generation; and simple integration into existing asset production tools and pipelines. Our experimental results show that artist controlled indirect illumination is a viable alternative to existing methods.
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Drescher, Michael Stuart. "A Flattened Hierarchical Scheduler for Real-Time Virtual Machines." Thesis, Virginia Tech, 2015. http://hdl.handle.net/10919/78125.
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The recent trend of migrating legacy computer systems to a virtualized, cloud-based environment has expanded to real-time systems. Unfortunately, modern hypervisors have no mechanism in place to guarantee the real-time performance of applications running on virtual machines. Past solutions to this problem rely on either spatial or temporal resource partitioning, both of which under-utilize the processing capacity of the host system. Paravirtualized solutions in which the guest communicates its real-time needs have been proposed, but they cannot support legacy operating systems. This thesis demonstrates the shortcomings of resource partitioning using temporally-isolated servers, presents an alternative solution to the scheduling problem called the KairosVM Flattening Scheduling Algorithm, and provides an implementation of the algorithm based on Linux and KVM. The algorithm is analyzed theoretically and an exact schedulability test for the algorithm is derived. Simulations show that the algorithm can schedule more than 90% of all randomly generated tasksets with a utilization less than 0.95. In comparison to the state-of-the-art server based approach, the KairosVM Flattening Scheduling Algorithm is able to schedule more than 20 times more tasksets with utilization of 0.95. Experimental results demonstrate that the Linux-based implementation is able to match the deadline satisfaction ratio of a state-of-the-art server-based approach when the taskset is schedulable using the state-of-the-art approach. When tasksets are unschedulable, the implementation is able to increase the deadline satisfaction ratio of Vanilla KVM by up to 400%. Furthermore, unlike paravirtualized solutions, the implementation supports legacy systems through the use of introspection.Master of Science
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Kämpe, Eddie. "Cloud execution environment for real-time media applications." Thesis, KTH, Skolan för informations- och kommunikationsteknik (ICT), 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-176049.
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Smartphones and other Internet of Things devices have become a rapidly growing topic. Along with the growth comes new technologies, likeWeb Real- Time Communication (WebRTC), that enables richer services to be built for the devices. These kind of services are typically consumed on-demand, in shorter periods at a time. Likewise have cloud computing exploded in popularity during the last years. Cloud computing offers compelling advantages, such as rapid elasticity and on-demand usage, that allow servers' resource utilization to be more effcient. The flexibility of allocating and releasing resources swiftly as they are required, enables services that run in the cloud to adopt to ephemeral workloads. The research in this thesis targets a real-time video streaming service that is based on WebRTC. Incoming streams are handled by Multipoint Control Units (MCUs) that have the responsibility to redistribute the incoming streams to the consumers. Scaling horizontally aligns well with the idea of cloud computing. The work in this thesis is based on the extreme case where each of the incoming streams are handled by a separate MCU. The thesis presents the process of finding a exible Cloud Execution Environment (CEE) for the streaming service. The process includes an analysis of the streaming service's requirements, an evaluation of existing solutions, and an implementation. Moreover, the thesis includes a discussion about the capabilities of the implemented system. The result of the thesis is a CEE upon which the streaming service can be deployed and managed. The developed CEE allows any workload that is encapsulated within a Docker container to be orchestrated, not exclusively the streaming service, which makes the implementation viable to other cloud computing projects.Användandet av smartphones och andra "Internet of Things"-enheter ökar snabbt. I takt med ökningen, så släpps nya tekniker som möjliggör utveckling av mer avancerade tjänster. Ett exampel är Web Real-Time Communication (WebRTC). Den här typen av tjänster konsumeras oftast sporadiskt under kortare tidsintervall. även cloud computing har drastiskt ökat i popularitet under de senaste åren. Hög elasticitet samt möjligheten att allokera datorresurser på begäran har medfört att utnyttjandegraden av datorers kapacitet kan höjas. Flexibiliteten att snabbt kunna allokera och frigöra resurser möjliggör att tjänster kan utvecklas för att utnyttja upp- och nerskalningsm öjligheterna bättre, även för kortvariga lastökningar. Forskningen i rapporten riktar in sig på ett system för videoströmning mellan användare i realtid baserat påa WebRTC. Inkommande strömmar hanteras av Multipoint Control Units (MCUs), som har som uppgift att vidaredistribuera strömmarna till andra användare som vill spela upp strömmen. Horisontell skalning och cloud computing har mycket gemensamt. Det underliggande arbetet till den här rapporten fokuserar på ett extremfall, där varje inkommande videoström hanteras av en enskild MCU. Den här uppsatsen presenterar den process som användes för att ta fram en lämplig molnlösning för strömningssystemet. Processen beståar av en kravanalys av strömningssystemet, en jämförelse av befintliga lösningar samt en implementation av en molnlösning. Slutligen så innehåller uppsatsen en utvärdering av implementationen. Resultatet av uppsatsen är en molnlösning som videoströmningssystemet kan driftsättas och köras på. Molnlösningen är inte begränsad till videoströmningssystemet utan klarar av att hantera alla applikationer som paketerats inuti Docker-kapslar. Molnlösningen är så pass generell att den kan användas till andra projekt inom cloud computing.
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Forsberg, Nils. "Evaluation of Real-Time Performance in Virtualized Environment." Thesis, Mälardalens högskola, Akademin för innovation, design och teknik, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:mdh:diva-12402.
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In this report is documented the research, tests and conclusions of a thesis work with the aim of investigating the possibilities of running real-time tasks in a virtualization environment. First we introduce the reader to the concepts and technology we will be touching on, and then we investigate the available solutions. We find that most of these are merely in a theoretical or development stage, and so we evaluate them theoretically. We also attempt to test one of the solutions that are fully developed and available, but fail because of issues related to the design of the solution. Based on our experiences and evaluations we come to the conclusion that the solutions available are lacking, and we give a suggestion of our own that we think should address the issues we have found.
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Han, Wan Yi. "Real-time transport protocol in a wireless environment." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape4/PQDD_0013/MQ61438.pdf.
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Slater, Howard James. "Real time emulation environment for digital control development." Thesis, University of Newcastle Upon Tyne, 1997. http://hdl.handle.net/10443/925.
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Simulation is a powerful tool for developing electric drive systems. Simulations allow the designer to experiment with control algorithms and hardware systems in a safe environment. To this end simulation is becoming increasingly popular. On'-line simulation does have its limitations in that the controller developed during the simulation period has eventually to be transferred to the target processor which will operate in the actual drive system. If, however, a real-time simulation environment could be realised, then the actual controller running in the actual target processor could be included in the simulation. Therefore no translation of code would be required once the controller had been developed and tested within the simulation. This would obviously lead to a reduction in development time and eliminate any possibility of introducing errors due to the translation between the simulated and actual controllers. This thesis describes the development of such a system using a multiple digital signal processing environment. The real-time simulated drive is operated in parallel with an experimental drive to allow a direct comparison between the two. The ability of the multiple processing system to operate in real-time has allowed the whole concept of simulation to be taken a stage further by the development of a real-time power level simulator. This simulator is capable of emulating a machine and load in real-time with real level of voltage and current. It is designed to replace a real machine during the development and testing stages of drive manufacture. This Virtual Machine is a controllable source/sink which is driven by the real-time simulation, and because of this the Virtual Machine takes on the characteristics of any choice of model within the real-time simulation. Moreover, because of its ability to handle bi-directional power flow, the Virtual machine can be programmed to emulate motors or generators. The Virtual Machine also includes the emulation of loads, thus making it extremely flexible and of interest to applications such as machine tools, electric vehicles, and wind generators, to name but a few.
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Chen, Deji. "Real-time data management in the distributed environment /." Digital version accessible at:, 1999. http://wwwlib.umi.com/cr/utexas/main.
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Molmer, Matthew. "Spatial orientation and familiarity in a small-scale real environment using PC-based virtual environment technology." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2005. http://library.nps.navy.mil/uhtbin/hyperion/05Sep%5FMolmer.pdf.
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Thesis (M.S. in Modeling, Virtual Environments, and Simulations (MOVES))--Naval Postgraduate School, September 2005.Thesis Advisor(s): Rudy Darken, Perry McDowell. Includes bibliographical references (p. 47). Also available online.
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Garrido, Randy A. "A real-time rope model suitable for game engine usage." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2004. http://library.nps.navy.mil/uhtbin/hyperion/04Sep%5FGarrido.pdf.
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Thesis (M.S. in Modeling, Virtual Environments and Simulation)--Naval Postgraduate School, Sept. 2004.Thesis advisor(s): Michael J. Zyda. Includes bibliographical references (p. 59). Also available online.
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Timchenko, Alexander Nikolai. "Real-time dynamics for interactive environments." [College Station, Tex. : Texas A&M University, 2007. http://hdl.handle.net/1969.1/ETD-TAMU-2122.
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Vernier, Michael Anthony. "Virtual Sensor System: Merging the Real World with a Simulation Environment." The Ohio State University, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=osu1282138118.
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Young, Roy David. "NPSNET-IV : a real-time, 3D distributed interactive virtual world /." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 1993. http://handle.dtic.mil/100.2/ADA274942.
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Waizenegger, Wolfgang. "Real-time 3D-based Virtual Eye Contact for Video Communication." Doctoral thesis, Humboldt-Universität zu Berlin, 2019. http://dx.doi.org/10.18452/20159.
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Das Problem des fehlenden Augenkontaktes vermindert den Eindruck einer natürlichen Kommunikationssituation bei Videokonferenzen. Während eine Person auf den Bildschirm blickt, wird sie von Kameras aufgenommen, die sich normalerweise direkt daneben befinden. Mit dem Aufkommen von massiv paralleler Computer Hardware und ganz speziell den sehr leistungsstarken Spielegrafikkarten ist es möglich geworden, viele Eingabeansichten für eine Echtzeit 3D Rekonstruktion zu verarbeiten. Eine größere Anzahl von Eingabeansichten mildert Verdeckungsprobleme ab und führt zu vollständigeren 3D Daten. In dieser Arbeit werden neue Algorithmen vorgeschlagen, welche eine hochqualitative Echtzeit 3D Rekonstruktion, die kontinuierliche Anpassung der photometrischen Kameraparameter und die benutzerunabhängige Schätzung der Augenkontaktkameras ermöglichen. Die Echtzeit 3D Analyse besteht aus zwei komplementären Ansätzen. Einerseits gibt es einen Algorithmus, der auf der Verarbeitung geometrischer Formen basiert und auf der anderen Seite steht eine patchbasierte Technik, die 3D Hypothesen durch das Vergleichen von Bildtexturen evaluiert. Zur Vorbereitung für die Bildsynthese ist es notwendig, Texturen von verschiedenen Ansichten anzugleichen. Hierfür wird die Anwendung eines neuen Algorithmus zur kontinuierlichen photometrischen Justierung der Kameraparameter vorgeschlagen. Die photometrische Anpassung wird iterativ, im Wechsel mit einer 3D Registrierung der entsprechenden Ansichten, ausgeführt. So ist die Qualität der photometrischen Parameter direkt mit jener der Ergebnisse der 3D Analyse verbunden und vice versa. Eine weitere wichtige Voraussetzung für eine korrekte Synthese der Augenkontaktansicht ist die Schätzung einer passenden virtuellen Augenkontaktkamera. Hierfür wird die Augenkontaktkamera kontinuierlich an die Augenposition der Benutzer angeglichen. Auf diese Weise wird eine virtuelle Kommunikationsumgebung geschaffen, die eine natürlichere Kommunikation ermöglicht.A major problem, that decreases the naturalness of conversations via video communication, is missing eye contact. While a person is looking on the display, she or he is recorded from cameras that are usually attached next to the display frame. With the advent of massively parallel computer hardware and in particular very powerful consumer graphics cards, it became possible to simultaneously process multiple input views for real-time 3D reconstruction. Here, a greater amount of input views mitigate occlusion problems and lead to a more complete set of 3D data that is available for view synthesis. In this thesis, novel algorithms are proposed that enable for high quality real-time 3D reconstruction, the on-line alignment of photometric camera parameters, and the automatic and user independent estimation of the eye contact cameras. The real-time 3D analysis consist of two complementary approaches. On the one hand, a shape based algorithm and on the other hand, a patch based technique that evaluates 3D hypotheses via comparison of image textures. Preparative to rendering, texture from multiple views needs to be aligned. For this purpose, a novel algorithm for photometric on-line adjustment of the camera parameters is proposed. The photometric adjustment is carried out iteratively in alternation with a 3D registration of the respective views. In this way, the quality of photometric parameters is directly linked to the 3D analysis results and vice versa. Based on the textured 3D data, the eye contact view is rendered. An important prerequisite for this task is the estimation of a suitable virtual eye contact camera. In this thesis, a novel approach is formulated that enables for an automatic adaptation to arbitrary new users. Therefor, the eye contact camera is dynamically adapted to the current eye positions of the users. In this way, a virtual communication environment is created that allows for a more natural conversation.
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Riva, Christian. "A programming environment for real-time multi-threaded systems." Thesis, University of Ottawa (Canada), 1995. http://hdl.handle.net/10393/10199.
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In recent years, the rapid progress in the functionality, performance, and cost of VLSI technology has made multiprocessor computer platforms feasible and cost-effective. The key benefit of these platforms is their ability to offer true concurrency at the physical layer, through the replication of processor, memory and I/O facilities, and at the logical layer, through the support for multi-tasking and multi-threading. For many applications, such as those found in the real-time problem domain, the concurrent nature of these platforms bring numerous advantages. To this date however, because of the lack of real-time concurrent programming tools, delivering the potential benefits of multiprocessing directly to these applications has proven elusive. This thesis proposes the Multi-Activity Programming Environment (MAPE) which allows developers to exploit the concurrent capabilities of multiprocessor platforms while remaining consistent with the requirements of the real-time problem domain. MAPE provides a programming model and a set of supporting tools which facilitate the decomposition of an application into cooperating entities and allow for the specification of deadline-based time constraints. The MAPE components also support the allocation of the platform's resources and the modification of the application's functionality based on run-time urgency considerations.