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<Paper uid="A00-1014">
  <Title>MIMIC: An Adaptive Mixed Initiative Spoken Dialogue System for Information Queries</Title>
  <Section position="2" start_page="0" end_page="0" type="intro">
    <SectionTitle>
1 Introduction
</SectionTitle>
    <Paragraph position="0"> In recent years, speech and natural language technologies have matured enough to enable the development of spoken dialogue systems in limited domains. Most existing systems employ dialogue strategies pre-specified during the design phase of the dialogue manager without taking into account characteristics of actual dialogue interactions. More specifically, mixed initiative systems typically employ rules that specify conditions (generally based on local dialogue context) under which initiative may shift from one agent to the other. Previous research, on the other hand, has shown that changes in initiative strategies in human-human dialogues can be dynamically modeled in terms of characteristics of the user and of the on-going dialogue (Chu-Carroll and Brown, 1998) and that adaptability of initiative strategies in dialogue systems leads to better system performance (Litman and Pan, 1999). However, no previous dialogue system takes into account these dialogue characteristics or allows for initiative-oriented adaptation of dialogue strategies.</Paragraph>
    <Paragraph position="1"> In this paper, we describe MIMIC, a voice-enabled telephone-based dialogue system that provides movie showtime information, emphasizing its dialogue management aspects. MIMIC improves upon previous systems along two dimensions. First, MIMIC automatically adapts dialogue strategies based on participant roles, characteristics of the current utterance, and dialogue history. This automatic adaptation allows appropriate dialogue strategies to be employed based on both local dialogue context and dialogue history, and has been shown to result in significantly better performance than non-adaptive systems. Second, MIMIC employs an initiative module that is decoupled from the goal selection process in the dialogue manager, while allowing the outcome of both components to jointly determine the strategies chosen for response generation. As a result, MIMIC can exhibit drastically different dialogue behavior with very minor adjustments to parameters in the initiative module, allowing for rapid development and comparison of experimental prototypes and resulting in general and portable dialogue systems.</Paragraph>
  </Section>
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