2009 Papers

Agents cannot be decoupled from their environment. An agent perceives and acts in a world and the model of the world influences how the agent makes decisions. Most systems with virtual embodied agents simulate the environment within a specific realization engine such as the graphics engine. As a consequence, these agents are bound to a particular kind of environment which compromises their reusability across different applications. We propose the ION Framework, a framework for simulating... Read more

Effective speakers engage their whole body when they gesture. It is difficult, however, to create such full body motion in animated agents while still supporting a large and flexible gesture set. This paper presents a hybrid system that combines motion capture data with a procedural animation system for arm gestures. Procedural approaches are well suited to supporting a large and easily modified set of gestures, but are less adept at producing subtle, full body movement.... Read more

Embodied agents are a powerful paradigm for current and future multimodal interfaces, yet require high effort and expertise for their creation, assembly and animation control. Therefore, open animation engines and high-level control languages are required to make embodied agents accessible to researchers and developers. In this paper, we present EMBR, a new realtime character animation engine that offers a high degree of animation control via the EMBRScript language. We argue that a new layer of... Read more

Actor agents in a virtual reality and interactive drama must deliver a believable performance. This is challenging and many issues need to be resolved. One prominent problem is that the goals of a character in an emergent interactive drama may conflict with demands for coherency in the drama's progress. We propose an approach to resolve this that uses Object Oriented Bayesian networks and intelligent agents with dual roles: an actor role focused on the dramatic... Read more

This paper describes the design and implementation of a virtual agent that is capable of providing customers in a 3D online shop with advice. Based on a product knowledge base, a conversation model and a model of the shop, the agent communicates with the customer through text based dialogues and leads the customer through the virtual world using gestures. Read more

In this paper we present an implementation of a embodied conversational agent that serves as a virtual tour guide in Second Life. We show how we combined the abilities of a conversational agent with navigation in the world and present some preliminary evaluation results. Read more

This paper describes a model for generating steering behaviors of groups of characters based on the biologically-motivated space colonization algorithm. This algorithm has been used in the past for generating leaf venation patterns and tree structures, simulating the competition for space between growing veins or branches. Adapted to character animation, this model is responsible for the motion control of characters providing robust and realistic group behaviors by adjusting just a few parameters. The main contributions... Read more

The challenge of making a virtual world believable includes a requirement for AI entities which autonomously react to a dynamic environment. After the breakthroughs in believability introduced by modern lightning and physics techniques, the focus is shifting to better AI behavior sophistication. Avatars and agents in a realistic virtual environment must exhibit a certain degree of presence and awareness of the surroundings, reacting consistently to unexpected contingencies and social situations. Unconscious reactions serve as evidence... Read more

This paper describes the challenges of getting ground truth affective labels for spontaneous video, and presents implications for systems such as virtual agents that have automated facial analysis capabilities. We first present a dataset from an intelligent tutoring application and describe the most prevalent approach to labeling such data. We then present an alternative labeling approach, which closely models how the majority of automated facial analysis systems are designed. We show that while participants, peers... Read more

Enabling virtual agents to quickly and accurately infer users' psychological characteristics such as their personality could support a broad range of applications in education, training, and entertainment. With a focus on narrative-centered learning environments, this paper presents an inductive framework for inferring users' psychological characteristics from observations of their interactions with virtual agents. Trained on traces of users' interactions with virtual agents in the environment, psychological user models are induced from the interactions to accurately... Read more