Metacomputing

Reviewer: Valentin Cristea

Showcase was a research exhibition, part of the ACM-sponsored SIGGRAPH'92 Conference held in Chicago from July 27 to 31, 1992. I was not able to attend this exhibition, but this interesting group of papers gives a representation of Showcase. They refer to visualization in networked environments, addressing four Showcase themes: local heterogeneous networked environments, remote visualization and collaboration, novel visual interfaces, and specific applications. Smarr and Catlett Metacomputing is related to the use of powerful computing resources transparently available to the user via a networked environment. Three steps are necessary to realize a metacomputer. The first integrates different software and hardware resources into high-performance networks to make the user's job easier. The second stage involves distributing a simple application across several computers. The third is creating a transparent national network that will increase the computational resources available to an application. The local area metacomputer at the National Center for Supercomputing Applications is an example of the first stage, and the capabilities demonstrated in the SIGGRAPH'92 Showcase represent the beginnings of the second stage. The details included in the paper are representative of the architecture of a metacomputer and of the kind of applications it is able to perform. These applications belong to three fundamental areas of computer science, theoretical simulation, instrument/sensor control, and data navigation, and have a common important characteristic: they require several interconnected computers to work on a single problem at the same time. The specific claims of the applications and their performances on metacomputers are presented in the paper. Mercurio et al. The subject of “The Distributed Laboratory” is an interactive visualization environment for electron microscopy and three-dimensional imaging. The authors describe the Microscopist's Workstation (MWS) project, whose goal is to investigate the potential advantages afforded by coupling a scientific instrument under computer control with interactive visualization software. The sophisticated instrument is a high-voltage electron microscope. The results are a distributed laboratory and many areas of possible investigation. The MWS project addresses three of them: integrating a scientific instrument into the computing environment as a computer peripheral, available to researchers at remote sites (spatial distribution of the facility); seamless management of supercomputing resources; and multi user collaboration based on replicated data acquisition and computational resources available to the workstation user interface. The result of the project is presented in the form of a scenario, describing the actions of a researcher issuing commands addressed to the dedicated workstation. Some operations at the microscope site are still to be automated. The actual configuration of the LAN embedding the microscope is also presented. Cruz-Neira et al. The third paper presents the CAVE, a new virtual reality interface. Research in virtual reality dates from 1965, when Ivan E. Sutherland proposed an interface that would completely override the user's senses, totally immersing her or him in the computer simulation. After describing the four aspects of modern virtual reality (the cathode-ray tube, the head-mounted display, the binocular omni-oriented monitor , and the audiovisual experience automatic virtual environment (CAVE)), the authors compare their performance, taking into account immersion category and visualization issues. The first reflects the degree of the suspension of disbelief, while the second is the effectiveness of the visualization. The virtues of the CAVE approach are highlighted by the results of these comparisons. The next section describes the CAVE implementation. Abstractly, CAVE consists of a room whose walls, ceiling, and floor surround a viewer with projected images. At the time the paper was written, the implementation of CAVE used two projecting screens instead of five. The implementation problems and the display hardware are presented. Finally, several applications of the CAVE to be featured at Showcase are presented. Carlbom et al. A collaborative scientific visualization environment, where scientists, engineers, and physicians work together on modeling and analyzing empirical data using tools from computer graphics, computer vision, and image processing, is presented. The paper begins with some hypothetical scenarios that illustrate how such an environment could be used. They differ by the field of application (medicine, neuroscience, or engineering), and have similarities in the techniques used to visualize, quantify, and interact with the data and the models. These lead to the idea of constructing a common scientific visualization environment that supports such diverse applications. Three projects are discussed: interactive modeling and visualization of medical and biological data; three-dimensional shape acquisition, modeling, manipulation, and three-dimensional faxes; and teleconferencing with personal computers. The demonstrations at the SIGGRAPH'92 showcase (teleconferencing of today and tomorrow) and the necessary hardware and software are also presented. The paper ends with a section about future research. Conclusion T his collection of papers on visualization in networked environments is homogeneous in structure and presentation. It provides readers with the current state of the art in networked visual computational science. The essentials of the ongoing research projects are described in general terms. Hence the papers are useful to computer scientists and to all potential users of networked environments. The accompanying illustrative material is well selected and suggestive.