Recent years have witnessed the birth of a new paradigm for learning environments: animated pedagogical agents. These lifelike autonomous characters cohabit learning environments with students to create rich, face-to-face learning interactions. This opens up exciting new possibilities; for example, agents can demonstrate complex tasks, employ locomotion and gesture to focus students'attention on the most salient aspect of the task at hand, and convey emotional responses to the tutorial situation. Animated pedagogical agents offer great promise for broadening the bandwidth of tutorial communication and increasing learning environments' ability to engage and motivate students. This article sets forth the motivations behind animated pedagogical agents, describes the key capabilities they offer, and discusses the technical issues they raise. The discussion is illustrated with descriptions of a number of animated agents that represent the current state of the art.

We present a model of dialogue for embodied virtual agents that can communicate with multiple (human and virtual) agents in a multi-modal setting, including face-to-face spoken and nonverbal, as well as radio interaction, spanning multiple conversations in support of an extended complex task.

A growing number of research projects both in academia and industries have started to investigate the use of animated agents in the interface. Such agents, either based on real video, cartoon-style drawings or even model-based 3D graphics, are likely to become integral parts of future user interfaces. To be useful, however, interface agents have to be intelligent in the sense that they exhibit a reasonable behavior. In this paper, we present a system that uses a lifelike character, the so-called PPP Persona, to present multimedia material to the user. This material has been either automatically generated or fetched from the web and modified if necessary. The underlying approach is based on our previous work on multimedia presentation planning. This core approach is complemented by additional concepts, namely the temporal coordination of presentation acts and the consideration of the human-factors dimension of the added visual metaphor.

Animated agents - based either on real video, cartoon-style drawings or even model-based 3D graphics - offer great promise for computer-based presentations as they make presentations more lively and appealing and allow for the emulation of conversation styles known from human-human communication. In this paper, we describe a life-like interface agent which presents multimedia material to the user following the directives of a script. The overall behavior of the presentation agent is partly determined by such a script, and partly by the agent's self-behavior. In our approach, the agent's behavior is defined in a declarative specification language. Behavior specifications are used to automatically generate a control module for an agent display system. The first part of the paper describes the generation process which involves AI planning and a two-step compilation. Since the manual creation of presentation scripts is tedious and error-prone, we also address the automated generation of pr...

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.

Prior research into embodied interface agents has found that users like them and find them engaging. In this paper, we argue that embodiment can serve an even stronger function if system designers use actual human conversational protocols in the design of the interface. Communicative behaviors such as salutations and farewells, conversational turn-taking with interruptions, and referring to objects using pointing gestures are examples of protocols that all native speakers of a language already know how to perform and that can thus be leveraged in an intelligent interface. We discuss how these protocols are integrated into Rea, an embodied, multi-modal conversational interface agent who acts as a real-estate salesperson, and we show why embodiment is required for their successful implementation.

Rapid growth of competition on the electronic market place, will generate the demand for new innovative communication styles with web users. In this paper, we develop an operational approach for the automated generation of hypermedia presentations. Unlike conventional hypermedia, we use a life-like presentation agent which presents the generated material, and guides the user through a dynamically expanding navigation space. The approach relies on a model that combines behavior planning for life-like characters with concepts from hypermedia authoring such as timeline structures and navigation graphs.

In this paper, we argue for embodied conversational characters as the logical extension of the metaphor of human -- computer interaction as a conversation. We argue that the only way to fully model the richness of human faceto -face communication is to rely on conversational analysis that describes sets of conversational behaviors as fulfilling conversational functions, both interactional and propositional. We demonstrate how to implement this approach in Rea, an embodied conversational agent that is capable of both multimodal input understanding and output generation in a limited application domain. Rea supports both social and task-oriented dialogue. We discuss issues that need to be addressed in creating embodied conversational agents, and describe the architecture of the Rea interface. Keywords Conversational Characters, Multimodal Input, Intelligent Agents, Multimodal Output INTRODUCTION The metaphor of face-to-face conversation has been successfully applied to human-interfac...

Reearch into virtual environments on the one hand and artificial intelligence and artificial life on the other has largely been carried out by two different groups of people with different preoccupations and interests, but some convergence is now apparent between the two fields. Applications in which activity independent of the user takes place --- involving crowds or other agents --- are beginning to be tackled, while synthetic agents, virtual humans and computer pets are all areas in which techniqes from the two fields require strong integration. The two communities have much to learn from each other if wheels are not to be reinvented on both sides. This paper reviews the issues arising from combining artificial intelligence and artificial life techniques with those of virtual environments to produce just such intelligent virtual environments. The discussion is illustrated with examples that include environments providing knowledge to direct or assist the user rather than r...

In this paper we describe the computational and architectural requirements for systems which support real-time multimodal interaction with an embodied conversational character. We argue that the three primary design drivers are real-time multithreaded entrainment, processing of both interactional and propositional information, and an approach based on a functional understanding of human face-toface conversation. We then present an architecture which meets these requirements and an initial conversational character that we have developed who is capable of increasingly sophisticated multimodal input and output in a limited application domain.