Hansrudi Noser

Dynamic 3D visualization of database-defined tree structures on the WWW by using rewriting systems

This paper presents a new Web-based technique for visualizing dynamically large hierarchies, tree or category structures in 3D worlds. The technique uses CGI-scripting, SQL queries and applet-based production systems to visualize in an efficient and versatile manner general category structures that are stored in relational databases. First, appropriate SQL queries extract the hierarchical category or tree structure from the database. Then, the minimal information is transmitted over the net to the users applet that generates a production system according to an optional visualization model. The interactive applet builds the corresponding 3D world and visualizes the category structure. As a test-bed for our Web-based visualization technique we use a commercial e-commerce framework and extended it with the corresponding features. We illustrate our technique by visualizing the complete mall structure according to different visualization models, such as axial trees, cone trees and enclosure models, for instance.

A rule-based interactive behavioral animation system for humanoids

We present a versatile, behavioral, and rule-based animation system that includes autonomous humanoid actors whose behavior is based on synthetic sensors that are used for perceiving the virtual environment. We combine the following in a consistent approach: L-systems, a behavioral production rule system; a particle system; an acoustic environment model, including a speech recognition module; a virtual life network; and a humanoid library. Together, these systems create a real-time-structured virtual environment that both high-level autonomous humanoids and interactive users can easily share.

Towards autonomous, perceptive, and intelligent virtual actors

This paper explains methods to provide autonomous virtual humans with the skills necessary to perform stand-alone role in films, games and interictive television. We present current research developments in the Virtual Life of autonomous synthetic actors. After a brief description of our geometric. physical, and auditory Virtual Environments, we introduce the perception action principles with a few simple examples. We emphasize the concept of virtual sensors for virtual humans. In particular, we describe our experiences in implementing virtual sensors such as vision sensors, tactile sensors, and hearing sensors. We then describe knowledge-based navigation. knowledge-based locomotion and in more details sensor-based tennis.

On Engineering Design Generation with XML-based Knowledge-Enhanced Grammars

One of the bottlenecks in conceptual engineering design is the pure amount of design information which the design engineer needs to take into consideration. The design information is heterogeneous and consists of the design object behavior (i.e. the physics), its intended geometrical form and composition (i.e. the geometry) and miscellaneous other information pieces concerning manufacturing cost and more.

Generic 3D Ball Animation Model for Networked Interactive VR Environments

This paper describes a versatile, robust, and parametric ball animation model that can be used in many types of interactive Virtual Reality (VR) environments. The generic model is particularly useful for animation of ball-like objects such as tennis balls and footballs in networked collaborative environments where low frame rates, network delays and information losses complicate collision detection of fast moving objects. The ball animation model includes a multi-level physical modeling as well as collision detection and treatment. Finally, the parameterization of typical applications is discussed.

Integration of optimization by genetic algorithms into an L-system-based animation system

In computer graphics L-systems represent a powerful rule-based language for modeling complex objects and their animation. However, designing objects and animations by rules is a difficult task because designers often cannot foresee the consequences of rules. This is especially true for non-experts in the domain. Therefore, we propose to enhance an L-system based animation system with evolutionary features based on genetic algorithms (GAs). These features support the designers task of interactively modeling objects and animations. Starting from an initial population of L-system-defined objects, the computer proposes iteratively new populations based on fitness value that are determined by the designers creative or functional criteria. Moreover, automatic optimization of L-system-defined objects/animations is possible if an appropriate fitness function can be found for a given problem. We present a concept to integrate optimization by genetic algorithms into an L-system based animation system. Typical examples, such as automatic function optimization and creative interactive design of objects, illustrate our work.

Distributed Virtual Reality environments based on rewriting systems

Ideally, virtual worlds should be dynamic, mutable, and complex in order to be attractive for immersed users. As such worlds can be designed easily by rewriting techniques, we propose a distributed Virtual Reality (VR) system that is based on an interactive animation system using a rewriting technique for geometric and behavioral modeling. The emphasis is on concepts and extensions for the integration of user immersion, user interaction, and networking into a rewriting-based animation system, Finally, the modeling of a ball game with two immersed users, as well as a virtual park, serve as case studies to illustrate the proposed concepts and extensions.

Lworld: an animation system based on rewriting

Lworld is a computer graphics animation system based on L-systems, a parallel rewriting technique used primarily in computer graphics for plant modeling. Because rule-based programming is a powerful technique, we use it as a basis for a general-purpose animation system. We describe the architecture, the features, and the programming language of the animation system. It is particularly well suited to model fractal curves, plants, fractal landscapes, group animation, visualization, and evolutionary optimizations. Lworld allows users to create real-time animations as well as raytraced image sequences for further movie production. It is freely available, and runs on PCs.

Sicherheit von E-Business-Anwendungen — Struktur und Quantifizierung

The rapid growth of the commercial use of the Internet goes along with a rising need for security for both customer and merchant. As many parties and different sys tems are involved, security becomes a complicated issue. Therefore, the need for definition, structuring, and quantification of security arises. This paper proposes a structured approach to analyze security measures and to quantify the overall security of an electronic business application. The quantifier is calculated through a security matrix which breaks down the assessment of security into smaller parts. These parts correspond to the loca tions, security objectives, and implemented security mechanisms of the application. The security quantifier can be used to analyze and design the application, and to compare it with other applications.

Application scenarios for scientific visualization and virtual reality using a CAVE infrastructure

Todays Virtual Reality applications require a high degree of immersion. This may be achieved by using a CAVE incorporating powerful 3D computer graphics workstations, panoramic multiple screen displays and projection walls, stereovision and interaction devices such as trackers and data gloves. This article describes Virtual Reality applications from the fields of scientific visualization in medicine and education embedded within the Blue-C environment, a state-of-the-art CAVE infrastructure.