The bottle-neck in most cloth simulation systems is that time steps must be small to avoid numerical instability. This paper describes a cloth simulation system that can stably take large time steps. The simulation system couples a new technique for enforcing constraints on individual cloth particles with an implicit integration method. The simulator models cloth as a triangular mesh, with internal cloth forces derived using a simple continuum formulation that supports modeling operations such as local anisotropic stretch or compression; a unified treatment of damping forces is included as well. The implicit integration method generates a large, unbanded sparse linear system at each time step which is solved using a modified conjugate gradient method that simultaneously enforces particles' constraints. The constraints are always maintained exactly, independent of the number of conjugate gradient iterations, which is typically small. The resulting simulation system is significantly fast...

All intelligence relies on search --- for example, the search for an intelligent agent's next action. Search is only likely to succeed in resource-bounded agents if they have already been biased towards finding the right answer. In artificial agents, the primary source of bias is engineering. This dissertation

Philosophy.

Abstract-- This paper presents a 3D simulator used for studying the motion control and autonomous navigation of a robotic fish. The simplified kinematics and hydrodynamics models are created for the simulator, including many other object models such as water, obstacles, sonar sensors and a swimming pool. The experimental results show that the use of this simulator is a realistic and convenient way to develop autonomous navigation algorithms for robotic fishes. I.

Abstract: Safe egress is one of the key design issues identified by facility planners, manager and inspectors. Computational tools are now available for the simulation and design of emergency evacuation and egress. However, these tools rely heavily on assumptions about human individual and social behaviors, which have been found to be oversimplified, inconsistent and even incorrect. Furthermore, the behaviors are usually incorporated into the computational model in an ad hoc manner. This paper presents a framework for studying human and social behavior from the perspectives of human decision-making and social interaction and to incorporate such behavior systematically in a dynamic computational model suitable for emergency egress analysis.

The numerical simulation of biomechanical models enables the behavioral animation of realistic artificial animals in virtual worlds. Unfortunately, even on high-end graphics workstations, the biomechanical simulation approach is at present computationally too demanding for the animation of numerous animals at interactive frame rates. We tackle this problem by replacing biomechanical animal models with fast kinematic replicas that reproduce the locomotion abilities of the original models with reasonable fidelity. Our technique is based on capturing motion data by systematically simulating the biomechanical models. We refer to it as synthetic motion capture, because of the similarity to natural motion capture applied to real animals. We compile the captured motion data into kinematic action repertoires that are sufficiently rich to support elaborate behavioral animation. Synthetic motion capture in conjunction with level-of-detail geometric modeling and object culling during rendering has enabled us to transform a system designed for the realistic, off-line biomechanical/behavioral animation of artificial fishes, into an interactive, stereoscopic, virtual undersea experience.

Virtual environments and the Internet provide an important medium for interactive collaborative learning. Immersive Virtual Environments appear able to support intuitive interaction techniques and metaphors. Our Identity Authoring Approach is aimed at our multicultural global society, and allows for multiple identities / persona to be created and used as interaction metaphors by users. The approach can be used to generate virtual environments in which the interaction is both intuitive and adaptable to the cultural background of the user, taking into account issues such as gendered and age-based identities. The approach is exemplified by focusing on interaction in virtual learning environments that engage and facilitate the introduction and experience of different cultures, by different users. 1 Introduction Virtual environments (VE) provide innovative ways to engage with cultural learning experiences. VE also provides important challenges for VE designers working with cultur...

The objective of this research is to study human and social behavior for emergency exit in buildings and facilities. Among the numerous regulatory provisions governing a facility design, one of the key issues identified by facility managers and building inspectors is safe egress. Design of egress for places of public assembly is a formidable problem in facility and safety engineering.

Recent work in behavioral animation has taken impressive steps toward autonomous, self-animating characters for use in production animation and interactive games. It remains difficult, however, to direct autonomous characters to perform specific tasks. This paper addresses the challenge by introducing cognitive modeling. Cognitive models go beyond behavioral models in that they govern what a character knows, how that knowledge is acquired, and how it can be used to plan actions. To help build cognitive models, we develop the cognitive modeling language CML. Using CML, we can imbue a character with domain knowledge, elegantly specified in terms of actions, their preconditions and their effects, and then direct the character's behavior in terms of goals. Our approach allows behaviors to be specified more naturally and intuitively, more succinctly and at a much higher level of abstraction than would otherwise be possible. With cognitively empowered characters, the animator need only speci...

A method for the generation of realistic real-time goal-directed virtual human arm motion is presented. Agents are endowed with a rudimentary synthetic vision and memory system that is used to gather and store data about objects in the vicinity.