David R. Traum

Information state and dialogue management in the TRINDI dialogue move engine toolkit

We introduce an architecture and toolkit for building dialogue managers currently being developed in the TRINDI project, based on the notions of information state and dialogue move engine. The aim is to provide a framework for experimenting with implementations of different theories of information state, information state update and dialogue control. A number of dialogue managers are currently being built using the toolkit, and we present overviews of two of them. We believe that this framework will make implementation of dialogue processing theories easier, also facilitating comparison of different types of dialogue systems, thus helping to achieve a prerequisite for arriving at a best practice for the development of the dialogue management component of a spoken dialogue system.

The TRAINS Project: A Case Study in Defining a Conversational Planning Agent

The TRAINS project is an effort to build a conversationally proficient planning assistant. A key part of the project is the construction of the TRAINS system, which provides the research platform for a wide range of issues in natural language understanding, mixed-initiative planning systems, and representing and reasoning about time, actions and events. Four years have now passed since the beginning of the project. Each year we have produced a demonstration system that focused on a dialog that illustrates particular aspects of our research. The commitment to building complete integrated systems is a significant overhead on the research, but we feel it is essential to guarantee that the results constitute real progress in the field. This paper describes the goals of the project, and our experience with the effort so far. .pp This paper is to appear in the Journal of Experimental and Theoretical AI, 1995.

The Information State Approach to Dialogue Management

We introduce the information state approach to dialogue management, and show how it can be used to formalize theories of dialogue in a manner suitable for easy implementation. We also show how this approach can lead to better engineering of dialogue management components of dialogue systems, allowing for separate development of modular system fundamentals, dialogue theories, and domain-specific dialogue systems, in a manner where components can more easily be reused. TrindiKit is a tool instantiating the lowest level, and allowing straightforward implementation of dialogue theories formalized using the information state approach. We briefly describe several dialogue systems built using TrindiKit, and how components have been successfully further developed and reused in other projects.

Embodied agents for multi-party dialogue in immersive virtual worlds

Immersive virtual worlds are increasingly being used for education, training, and entertainment, and virtual humans that can interact with human users in these worlds play many important roles. However, current computational models of dialogue do not address the issues that arise with face-to-face communication situated in three-dimensional worlds, such as the proximity and attentional focus of others, the ability to maintain multi-party conversations, and the interplay between speech and nonverbal signals. This paper presents a new model that integrates and extends prior work on spoken dialogue and embodied conversational agents, and describes an initial implementation that has been applied to training in virtual reality.

Discourse Obligations in Dialogue Processing

We show that in modeling social interaction, particularly dialogue, the attitude of obligation can be a useful adjunct to the popularly considered attitudes of belief, goal, and intention and their mutual and shared counterparts. In particular, we show how discourse obligations can be used to account in a natural manner for the connection between a question and its answer in dialogue and how obligations can be used along with other parts of the discourse context to extend the coverage of a dialogue system.

Conversation Acts in Task-Oriented Spoken Dialogue

A linguistic forms compositional, timeless meaning can be surrounded or even contradicted by various social, aesthetic, or analogistic companion meanings. This paper addresses a series of problems in the structure of spoken language discourse, including turn‐taking and grounding. It views these processes as composed of fine‐grained actions, which resemble speech acts both in resulting from a computational mechanism of planning and in having a rich relationship to the specific linguistic features which serve to indicate their presence. The resulting notion of Conversation Acts is more general than speech act theory, encompassing not only the traditional speech acts but turn‐taking, grounding, and higher‐level argumentation acts as well. Furthermore, the traditional speech acts in this scheme become fully joint actions, whose successful performance requires full listener participation. This paper presents a detailed analysis of spoken language dialogue. It shows the role of each class of conversation acts in discourse structure, and discusses how each class can be processed and recognized. Conversation acts, it will be seen, better account for the success of conversation than speech act theory alone. They also provide a pragmatic view of meaning in which the literal/non‐literal distinction is simply irrelevant.

Toward a new generation of virtual humans for interactive experiences

Virtual humans - autonomous agents that support face-to-face interaction in a variety of roles - can enrich interactive virtual worlds. Toward that end, the Mission Rehearsal Exercise project involves an ambitious integration of core technologies centered on a common representation of task knowledge.

Toward virtual humans

This article describes the virtual humans developed as part of the Mission Rehearsal Exercise project, a virtual reality-based training system. This project is an ambitious exercise in integration, both in the sense of integrating technology with entertainment industry content, but also in that we have joined a number of component technologies that have not been integrated before. This integration has not only raised new research issues, but it has also suggested some new approaches to difficult problems. We describe the key capabilities of the virtual humans, including task representation and reasoning, natural language dialogue, and emotion reasoning, and show how these capabilities are integrated to provide more human-level intelligence than would otherwise be possible.

Sharing Solutions: Persistence and Grounding in Multimodal Collaborative Problem Solving

This article reports on an exploratory study of the relationship between grounding and problem solving in multimodal computer-mediated collaboration. This article examines two different media, a shared whiteboard and a MOO environment that includes a text chat facility. A study was done on how the acknowledgment rate (how often partners give feedback of having perceived, understood, and accepted partners contributions) varies according to the media and the content of interactions. It was expected that the whiteboard would serve to draw schemata that disambiguate chat utterances. Instead, results show that the whiteboard is primarily used to represent the state of problem solving and the chat is used for grounding information created on the whiteboard. These results are interpreted in terms of persistence: More persistent information is exchanged through the more persistent medium. The whiteboard was used as a shared memory rather than a grounding tool.

CONVERSATIONAL ACTIONS AND DISCOURSE SITUATIONS

We use the idea that actions performed in a conversation become part of the common ground as the basis for a model of context that reconciles in a general and systematic fashion the differences between the theories of discourse context used for reference resolution, intention recognition, and dialogue management. We start from the treatment of anaphoric accessibility developed in discourse representation theory (DRT), and we show first how to obtain a discourse model that, while preserving DRTs basic ideas about referential accessibility, includes information about the occurrence of speech acts and their relations. Next, we show how the different kinds of ‘structure’ that play a role in conversation—discourse segmentation, turn‐taking, and grounding—can be formulated in terms of information about speech acts, and use this same information as the basis for a model of the interpretation of fragmentary input.