Tomography is a popular technique to reconstruct the three-dimensional structure of an object from a series of two-dimensional projections. Tomography is resource-intensive and deployment of a parallel implementation onto Computational Grid platforms has been studied in previous work. In this work, we address on-line execution of the application where computation is performed as data is collected from an on-line instrument. The goal is to compute incremental 3-D reconstructions that provide quasi-real-time feedback to the user. We model on-line parallel tomography as a tunable application: trade-offs between resolution of the reconstruction and frequency of feedback can be used to accommodate various resource

Introduction The current trend in hardware for parallel graphics is to use clusters of off-the-shelf PCs instead of high-end super computers. This trend has emerged since the dramatic change in the price/performance ratio of today's PCs. Using large, high-resolution displays is another trend that is currently emerging. High resolution allows for detailed scientific visualization, and overcomes the limited screen resolution of standard monitors. Large displays also have applications in teaching environments, where multiple people (small groups or full classroom) are looking at a single large screen. The goal of this project is to investigate the field of parallel rendering in the context of scalable tiled displays. A renderer calculates a 2D picture from a 3D model specified by the programmer. A parallel renderer uses multiple processors to calculate a single image. The target system for this parallel renderer is a so-called tiled<F13.15

This paper analyzes the interactive virtual environments developed at an institution of informal education and discusses the issues involved in developing immersive interactive virtual archaeology projects for the broad public

Abstract. In this paper we describe a software system for building interactive virtual environments, particularly ones for virtual reality art works. It is meant to allow teams composed of experienced programmers and non-programming designers to work together on projects. It is an object-oriented framework, built upon existing toolkits for VR, real-time graphics, and audio. A number of common application features and tools are provided, simplifying world creation. 1.

The SmartPointer system provides a paradigm for utilizing multiple light-weight client endpoints in a real-time scientific visualization infrastructure. Together, the client and server infrastructure form a new type of data portal for scientific computing. The clients can be used to personalize data for the needs of the individual scientist. This personalization of a shared dataset is designed to allow multiple scientists, each with their laptops or iPaqs to explore the dataset from different angles and with different personalized filters. As an example, iPaq clients can display 2D derived data functions which can be used to dynamically update and annotate the shared data space, which might be visualized separately on a large immersive display such as a CAVE. Measurements are presented for such a system, built upon the ECho middleware system developed at Georgia Tech.

Introduction In 1992 the Electronic Visualization Laboratory (EVL) developed the CAVE. Now in the year 2000, with more than 200 CAVE and related projection-based VR environments around the world, there is a community that is eager to collaborate. The CAVE^TM Research Network (CAVERN) is an international alliance of research and industrial institutions equipped with CAVEs, ImmersaDesks^TM, and high performance computing resources, interconnected by high-speed networks. This high-end visualization hardware combined with high bandwidth networks allows us to explore new research problems and applications of this collaborative technology without being hindered by the limits of the existing Internet. The CAVE [Cruz-Neira et al, 1993] is a virtual reality (VR) system where the display is a 10 foot-cubed room that is rear-projected with stereoscopic images, creating the illusion that 3D objects appear to co-exist with the user in the room. A user dons a pair of lightweight liquid cry

The PARIS (Personal Augmented Reality Immersive System) is a new VR display device that was first prototyped as a virtual device in a CAVE, to aid in the development process. This initial prototyping in VR allowed the designers to save time and money, and to garner valuable feedback from prospective users, before finally committing the design to hardware. 1. Introduction The Electronic Visualization Laboratory at the University of Illinois at Chicago has developed several projection -based VR devices including the CAVE [1], the ImmersaDesk [2], and its successor the ImmersaDesk 2. Our recent work has focused on smaller desktop systems, such as the prototype for the plasma-display based ImmersaDesk 3 [4]. See Figure 1. All of these projection -based displays suffer from occlusion of the image by your hand or interaction device -- which can cause slight visual disorientation when trying to interact with nearby virtual objects. As an augmented reality device, the goal of the PARIS is to...

We present a new interaction metaphor for object-centric tasks in the form of a prototype VR system, ALCOVE. Through analytic calculations, we quantitatively demonstrate the benefits of restructuring the interaction volume offered by current systems. Our metrics show that many applications ' interaction volume increases by 1.5 to 2.6 times when using the ALCOVE system. We also offer an informal user task analysis and evaluations of previous VR systems that qualitatively support this improved interaction volume as well as demonstrate the need for a shift from room and desk-sized systems to desktop units. We present some testbed applications which benefit from this object-centric design and discuss some of the advantages and shortcomings of our system. Keywords: Virtual Reality, Human-Computer Interaction, Scientific Visualization 1 Introduction Virtual Reality systems have come to be regarded as important and useful tools for scientific and visualization applications. However, there ...

This paper describes a method for correcting static errors in the position component of a 6-degree-offreedom tracker in a projection-based VR system. This method allows users to observe where errors in the environment are significant and correct them interactively. Later touch-up correction is possible as well. This technique is based on superimposing targets in physical space with their virtual images. The only hardware addition to the VR system required is a few precisely placed targets. Keywords: Tracker calibration, Virtual Reality, Projection-Based VR, CAVE, ImmersaDesk. 1 Introduction 1.1 Motivation Six-degree-of-freedom (6DOF) trackers are widely used in VR systems. Computer graphics systems need information about the location of the user's eyes to generate an image of the scene from the correct, user centered perspective. At the same time the location of an input device like a glove or a wand is needed to enable user interactions with a virtual environment. Widely used elect...

This paper describes the construction of a single screen, projection-based VR display using commodity, or otherwise low-cost, components. The display is based on Linux PCs, and uses polarized stereo. Our aim is to create a system that is accessible to the many museums and schools that do not have large budgets for exploring new technology. In constructing this system we have been evaluating a number of options for the screens, projectors, and computer hardware.