This paper describes an approach for managing the interaction of human users with computer-controlled agents in an interactive narrative-oriented virtual environment. In these kinds of systems, the freedom of the user to perform whatever action she desires must be balanced with the preservation of the storyline used to control the system's characters. We describe a technique, narrative mediation, that exploits a plan-based model of narrative structure to manage and respond to users' actions inside a virtual world. We define two general classes of response to situations where users execute actions that interfere with story structure: accommodation and intervention. Finally, we specify an architecture that uses these definitions to monitor and automatically characterize user actions, and to compute and implement responses to unanticipated activity. The approach effectively integrates user action and system response into the unfolding narrative, providing for the balance between a user's sense of control within the story world and the user's sense of coherence of the overall narrative.

We describe the generation of communicative actions in an implemented embodied conversational agent. Our agent plans each utterance so that mul- tiple communicative goals may be realized opportunistically by a composite action including not only speech but also coverbat gesture that fits the con- text and the ongoing speech in ways representative of natural human conversation. We accomplish this by reasoning from a grammar which describes ges- ture declaratively in terms of its discourse function, semantics and synchrony with speech.

We describe an initial prototype of a holodeck-like environment that we have created for the Mission Rehearsal Exercise Project. The goal of the project is to create an experience learning system where the participants are immersed in an environment where they can encounter the sights, sounds, and circumstances of realworld scenarios. Virtual humans act as characters and coaches in an interactive story with pedagogical goals.

Smart avatars are virtual human representations controlled by real people. Given instructions interactively, smart avatars can act as autonomous or reactive agents. During a real-time simulation, a user should be able to dynamically refine his or her avatar's behavior in reaction to simulated stimuli without having to undertake a lengthy off-line programming session. In this paper, we introduce an architecture, which allows users to input immediate or persistent instructions using natural language and see the agents' resulting behavioral changes in the graphical output of the simulation. Keywords Autonomous agents, natural language processing, smart avatars, virtual environments. 1. INTRODUCTION In this paper, we describe smart avatars [28, 34], which are virtual representations of humans controlled by real people. Given instructions interactively, smart avatars can act as autonomous or reactive agents. During a real-time simulation, a user should be able to dynamically refine his ...

Abstract. Lifelike animated agents for knowledge-based learning environments can provide timely, customized advice to support learners ’ problem-solving activities. By drawing on a rich repertoire of emotive behaviors to exhibit contextually appropriate facial expressions and emotive gestures, these agents could exploit the visual channel to more effectively communicate with learners. To address these issues, this article proposes the emotive-kinesthetic behavior sequencing framework for dynamically sequencing lifelike pedagogical agents ’ full-body emotive expression. By exploiting a rich behavior space populated with emotive behaviors and structured by pedagogical speech act categories, a behavior sequencing engine operates in realtime to select and assemble contextually appropriate expressive behaviors. This framework has been implemented in a lifelike pedagogical agent, COSMO, who exhibits full-body emotive behaviors in response to learners ' problem-solving activities.

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Life-like characters are increasingly gaining the attention of researchers and commercial developers of user interfaces. A strong argument for using characters in the interface is that they enrich the repertoire of available options which allow to emulate more familiar communication styles for interacting with a computer. The focus of our work is on lifelike presentation agents. In this contribution, we present a framework for the development of presentation agents which can be utilized for a broad range of applications including personalized information delivery from the WWW.

This research was funded in part through fellowships from the Litton and Intel Corporations. Any opinions, findings and conclusions or recommendations expressed in this publication are those of the author and do not necessarily reflect those of the sponsors.

Emotions have a powerful impact on behavior and beliefs. The goal of our research is to create general computational models of this interplay of emotion, cognition and behavior to inform the design of virtual humans. Here, we address an aspect of emotional behavior that has been studied extensively in the psychological literature but largely ignored by computational approaches, emotion-focused coping. Rather than motivating external action, emotion-focused coping strategies alter beliefs in response to strong emotions. For example an individual may alter beliefs about the importance of a goal that is being threatened, thereby reducing their distress. We present a preliminary model of emotion-focused coping and discuss how coping processes, in general, can be coupled to emotions and behavior. The approach is illustrated within a virtual reality training environment where the models are used to create virtual human characters in high-stress social situations.

In this paper we discuss the application of aspects of a psychological theory about the relationship between speech and gesture to the implementation of interactive dialogue systems. We first lay out some uncontroversial facts about the interaction of speech and gesture in conversation and describe some psychological theories put forth to explain those data, settling on one theory as being the most interesting for interactive dialogue systems. We then lay out our implementation of an interactive dialogue system that is informed by the theory--- concentrating on two particular claims of the theory: that gesture and speech reflect a common conceptual source; and that the content and form of gesture is tuned to the communicative context and the actor's communicative intentions. We compare our work to some other similar interactive systems, and conclude with some thoughts about how both implementation and theory can benefit from this kind of close partnership. Epigraph Pan...