Proposed Enhancements to the X3D Geospatial Component

Web3D '09: Proceedings of the 14th International Conference on 3D Web Technology, June 2009, Pages 155–158.The article of record as published may be found at https://doi.org/10.1145/1559764.1559788The Geospatial Component of the X3D Standard suffers from some deficiencies that prevent its wider adoption. This paper addresses two of these deficiencies. The first problem is that in order to reduce spatial jitter content must be built with regionally defined GeoOrigin nodes. This approach is fine for localized regional geospatial data visualization requirements, but fails for accurately viewing data in a global context or for combining content with different GeoOrigins. The second problem is the limited options for providing terrain data to the browser for rendering. The GeoLOD node is not the optimal solution for allowing the X3D browser to render terrain data in a high performing manner. This paper presents solutions to these problems for consideration by the Web3D community

Modeling economic systems as locally-constructive sequential games

Real-world economies are open-ended dynamic systems consisting of heterogeneous interacting participants. Human participants are decision-makers who strategically take into account the past actions and potential future actions of other participants. All participants are forced to be locally constructive, meaning their actions at any given time must be based on their local states; and participant actions at any given time affect future local states. Taken together, these essential properties imply real-world economies are locally-constructive sequential games. This paper discusses a modeling approach, Agent-based Computational Economics, that permits researchers to study economic systems from this point of view. ACE modeling principles and objectives are first concisely presented and explained. The remainder of the paper then highlights challenging issues and edgier explorations that ACE researchers are currently pursuing

A modelling and networking architecture for distributed virtual environments with multiple servers.

Virtual Environments (VEs) attempt to give people the illusion of immersion that they are in a computer generated world. VEs allow people to actively participate in a synthetic environment. They range from a single-person running on a single computer, to multiple-people running on several computers connected through a network. When VEs are distributed on multiple computers across a network, we call this a Distributed Virtual Environment (DVE). Virtual Environments can benefit greatly from distributed strategies.A networked VE system based on the Client-Server model is the most commonly used paradigm in constructing DVE systems. In a Client-Server model, data can be distributed on several server computers. The server computers provide services to their own clients via networks. In some client-server models, however, a powerful server is required, or it will become a bottleneck. To reduce the amount of data and traffic maintained by a single server, the servers themselves can be distributed, and the virtual environment can be divided over a network of servers.The system described in this thesis, therefore, is based on the client-server model with multiple servers. This grouping is called a Distributed Virtual Environment System with Multiple- Servers (DVM). A DVM system shows a new paradigm of distributed virtual environments based on shared 3D synthetic environments. A variety of network elements are required to support large scale DVM systems. The network is currently the most constrained resource of the DVM system. Development of networking architectures is the key to solving the DVM challenge. Therefore, a networking architecture for implementing a DVM model is proposed. Finally, a DVM prototype system is described to demonstrate the validity of the modelling and network architecture of a DVM model

Requirements, Design, and Development of a Rapidly Reconfigurable, Photo-Realistic, Virtual Cockpit Prototype

The United States Air Force uses aircraft flight simulators for pilot training and mission rehearsal. They use a variety of simulators for this task ranging with prices ranging from $400,000 to$30,000,000. These simulators have specialized hardware that restricts reuse of their components and increases maintenance costs. Air Education and Training Command wants to reduce simulators cost and improve availability to the operational commands by supporting research in virtual reality flight simulators. This thesis looks at the development of a reconfigurable virtual cockpit in a distributed virtual environment that can be used for different aircraft as well as training scenarios. The thesis effort builds on a F-15 virtual cockpit previously developed at AFIT by creating a F-16. The Rapidly Reconfigurable Virtual Cockpit (RRVC) allows users to switch between an F-15 and F-16 during live simulation. All software models and aircraft geometry files are updated to reflect the current aircraft. The ability of a distributed virtual environment to support two unique aircraft flight simulators in a single application is encouraging. With the development of more aircraft, a single application can be provided to the operational pilot community that would support many aircraft at a fraction of the cost of today\u27s flight simulators

Network architecture for large-scale distributed virtual environments

Distributed Virtual Environments (DVEs) provide 3D graphical computer generated environments with stereo sound, supporting real-time collaboration between potentially large numbers of users distributed around the world. Early DVEs has been used over local area networks (LANs). Recently with the Internet's development into the most common embedding for DVEs these distributed applications have been moved towards an exploiting IP networks. This has brought the scalability challenges into the DVEs evolution. The network bandwidth resource is the more limited resource of the DVE system and to improve the DVE's scalability it is necessary to manage carefully this resource. To achieve the saving in the network bandwidth the different types of the network traffic that is produced by the DVEs have to be considered. DVE applications demand· exchange of the data that forms different types of traffic such as a computer data type, video and audio, and a 3D data type to keep the consistency of the application's state. The problem is that the meeting of the QoS requirements of both control and continuous media traffic already have been covered by the existing research. But QoS for transfer of the 3D information has not really been considered. The 3D DVE geometry traffic is very bursty in nature and places a high demands on the network for short intervals of time due to the quite large size of the 3D models and the DVE application requirements to transmit a 3D data as quick as possible. The main motivation in carrying out the work presented in this thesis is to find a solution to improve the scalability of the DVE applications by a consideration the QoS requirements of the 3D DVE geometrical data type. In this work we are investigating the possibility to decrease the network bandwidth utilization by the 3D DVE traffic using the level of detail (LOD) concept and the active networking approach. The background work of the thesis surveys the DVE applications and the scalability requirements of the DVE systems. It also discusses the active networks and multiresolution representation and progressive transmission of the 3D data. The new active networking approach to the transmission of the 3D geometry data within the DVE systems is proposed in this thesis. This approach enhances the currently applied peer-to-peer DVE architecture by adding to the peer-to-peer multicast neny_ork layer filtering of the 3D flows an application level filtering on the active intermediate nodes. The active router keeps the application level information about the placements of users. This information is used by active routers to prune more detailed 3D data flows (higher LODs) in the multicast tree arches that are linked to the distance DVE participants. The exploration of possible benefits of exploiting the proposed active approach through the comparison with the non-active approach is carried out using the simulation­based performance modelling approach. Complex interactions between participants in DVE application and a large number of analyzed variables indicate that flexible simulation is more appropriate than mathematical modelling. To build a test bed will not be feasible. Results from the evaluation demonstrate that the proposed active approach shows potential benefits to the improvement of the DVE's scalability but the degree of improvement depends on the users' movement pattern. Therefore, other active networking methods to support the 3D DVE geometry transmission may also be required

Enhanced Virtuality: Increasing the Usability and Productivity of Virtual Environments

Mit stetig steigender Bildschirmauflösung, genauerem Tracking und fallenden Preisen stehen Virtual Reality (VR) Systeme kurz davor sich erfolgreich am Markt zu etablieren. Verschiedene Werkzeuge helfen Entwicklern bei der Erstellung komplexer Interaktionen mit mehreren Benutzern innerhalb adaptiver virtueller Umgebungen. Allerdings entstehen mit der Verbreitung der VR-Systeme auch zusätzliche Herausforderungen: Diverse Eingabegeräte mit ungewohnten Formen und Tastenlayouts verhindern eine intuitive Interaktion. Darüber hinaus zwingt der eingeschränkte Funktionsumfang bestehender Software die Nutzer dazu, auf herkömmliche PC- oder Touch-basierte Systeme zurückzugreifen. Außerdem birgt die Zusammenarbeit mit anderen Anwendern am gleichen Standort Herausforderungen hinsichtlich der Kalibrierung unterschiedlicher Trackingsysteme und der Kollisionsvermeidung. Beim entfernten Zusammenarbeiten wird die Interaktion durch Latenzzeiten und Verbindungsverluste zusätzlich beeinflusst. Schließlich haben die Benutzer unterschiedliche Anforderungen an die Visualisierung von Inhalten, z.B. Größe, Ausrichtung, Farbe oder Kontrast, innerhalb der virtuellen Welten. Eine strikte Nachbildung von realen Umgebungen in VR verschenkt Potential und wird es nicht ermöglichen, die individuellen Bedürfnisse der Benutzer zu berücksichtigen. Um diese Probleme anzugehen, werden in der vorliegenden Arbeit Lösungen in den Bereichen Eingabe, Zusammenarbeit und Erweiterung von virtuellen Welten und Benutzern vorgestellt, die darauf abzielen, die Benutzerfreundlichkeit und Produktivität von VR zu erhöhen. Zunächst werden PC-basierte Hardware und Software in die virtuelle Welt übertragen, um die Vertrautheit und den Funktionsumfang bestehender Anwendungen in VR zu erhalten. Virtuelle Stellvertreter von physischen Geräten, z.B. Tastatur und Tablet, und ein VR-Modus für Anwendungen ermöglichen es dem Benutzer reale Fähigkeiten in die virtuelle Welt zu übertragen. Des Weiteren wird ein Algorithmus vorgestellt, der die Kalibrierung mehrerer ko-lokaler VR-Geräte mit hoher Genauigkeit und geringen Hardwareanforderungen und geringem Aufwand ermöglicht. Da VR-Headsets die reale Umgebung der Benutzer ausblenden, wird die Relevanz einer Ganzkörper-Avatar-Visualisierung für die Kollisionsvermeidung und das entfernte Zusammenarbeiten nachgewiesen. Darüber hinaus werden personalisierte räumliche oder zeitliche Modifikationen vorgestellt, die es erlauben, die Benutzerfreundlichkeit, Arbeitsleistung und soziale Präsenz von Benutzern zu erhöhen. Diskrepanzen zwischen den virtuellen Welten, die durch persönliche Anpassungen entstehen, werden durch Methoden der Avatar-Umlenkung (engl. redirection) kompensiert. Abschließend werden einige der Methoden und Erkenntnisse in eine beispielhafte Anwendung integriert, um deren praktische Anwendbarkeit zu verdeutlichen. Die vorliegende Arbeit zeigt, dass virtuelle Umgebungen auf realen Fähigkeiten und Erfahrungen aufbauen können, um eine vertraute und einfache Interaktion und Zusammenarbeit von Benutzern zu gewährleisten. Darüber hinaus ermöglichen individuelle Erweiterungen des virtuellen Inhalts und der Avatare Einschränkungen der realen Welt zu überwinden und das Erlebnis von VR-Umgebungen zu steigern

A white paper: NASA virtual environment research, applications, and technology

Research support for Virtual Environment technology development has been a part of NASA's human factors research program since 1985. Under the auspices of the Office of Aeronautics and Space Technology (OAST), initial funding was provided to the Aerospace Human Factors Research Division, Ames Research Center, which resulted in the origination of this technology. Since 1985, other Centers have begun using and developing this technology. At each research and space flight center, NASA missions have been major drivers of the technology. This White Paper was the joint effort of all the Centers which have been involved in the development of technology and its applications to their unique missions. Appendix A is the list of those who have worked to prepare the document, directed by Dr. Cynthia H. Null, Ames Research Center, and Dr. James P. Jenkins, NASA Headquarters. This White Paper describes the technology and its applications in NASA Centers (Chapters 1, 2 and 3), the potential roles it can take in NASA (Chapters 4 and 5), and a roadmap of the next 5 years (FY 1994-1998). The audience for this White Paper consists of managers, engineers, scientists and the general public with an interest in Virtual Environment technology. Those who read the paper will determine whether this roadmap, or others, are to be followed

A multigrid relevance filtering technique for distributed interactive simulation

Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1997.Includes bibliographical references (p. 45-46).by Harry Tsai.M.Eng