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<Paper uid="J98-3002">
  <Title>Collaborative Response Generation in Planning Dialogues</Title>
  <Section position="2" start_page="0" end_page="356" type="abstr">
    <SectionTitle>
1. Introduction
</SectionTitle>
    <Paragraph position="0"> In task-oriented collaborative planning dialogues, two agents work together to develop a plan for achieving their shared goal. Such a goal may be for one agent to obtain a Bachelor's degree in Computer Science or for both agents to go to a mutually desirable movie. Since the two agents each have private beliefs about the domain and about one another, it is inevitable that conflicts will arise between them during the planning process. In order for the agents to effectively collaborate with one another, each agent must attempt to detect such conflicts as soon as they arise, and to resolve them in an efficient manner so that the agents can continue with their task.</Paragraph>
    <Paragraph position="1"> Our analysis of naturally occurring collaborative planning dialogues shows that agents initiate two types of subdialogues for the purpose of resolving (potential) conflicts between the agents. First, an agent may initiate information-sharing subdialogues when she does not have sufficient information to determine whether to accept or reject a proposal made by the other agent. The purpose of such information-sharing subdialogues is for the two agents to share their knowledge regarding the proposal so that each agent can then knowledgeably reevaluate the proposal and come to an informed decision about its acceptance. Second, an agent may initiate collaborative negotiation subdialogues when she detects a conflict between the agents with respect to a proposal. The purpose of such collaborative negotiation subdialogues is for the * 600 Mountain Avenue, Murray Hill, NJ 07974, U.S.A. E-mail: jencc@bell-labs.com t Department of Computer and Information Sciences, Newark, DE 19716, U.S.A. E-marl: carberry@cis.udel.edu (~) 1998 Association for Computational Linguistics Computational Linguistics Volume 24, Number 3 two agents to resolve the detected conflict and agree on accepting the original proposal or perhaps some modification of it. For example, consider the following dialogue segment between a travel agent (T) and a customer (C) who is making reservations for two other agents  (1) T: Can we put them on American? (2) C: Why? (3) T: We're having a lot of problems on the USAir seat maps so we may not be able to get the seats they want.</Paragraph>
    <Paragraph position="2"> (4) But American whatever we request pretty much we get.</Paragraph>
    <Paragraph position="3"> (5) C: I don't know if they care about seats.</Paragraph>
    <Paragraph position="4"> (6) Let's go with USAir.</Paragraph>
    <Paragraph position="5"> (7) T: Are you sure they won't mind if they don't get seats next to each other? (8) C: I don't think they would care.</Paragraph>
    <Paragraph position="6"> (9) The USAir flight was recommended by the manager, so I think we should stick with it.</Paragraph>
    <Paragraph position="7"> (10) T: Okay.</Paragraph>
    <Paragraph position="8">  This dialogue segment illustrates how an agent may initiate an information-sharing subdialogue (utterances (2)-(4)) or a collaborative negotiation subdialogue (utterances (5)-(10)) to resolve (potential) disagreements between the agents. In utterance (2), C employs the Ask-Why strategy, one of four information-sharing strategies that we identified based on our analysis of collaborative planning dialogues, to gather information from T in order to reevaluate T's proposal in (1). When taking into account the information obtained in utterances (3) and (4), however, C's reevaluation of the proposal results in her rejecting the proposal, i.e., C detects a conflict with T regarding which airline they should book on. Thus, in utterances (5) and (6), C initiates a collaborative negotiation subdialogue in an attempt to convince T that they should go with USAir. This negotiation subdialogue eventually leads to T accepting C's plan in (10).</Paragraph>
    <Paragraph position="9"> One very important aspect of natural language generation is identification of appropriate content during response generation. Although negotiation and conflict resolution are an integral part of collaborative activity, previous research has not provided mechanisms that enable a system to effectively participate in dialogues such as the above. This paper presents our strategies and algorithms for initiating and generating responses in information-sharing and negotiation subdialogues. As will be noted in' Section 4, we view each utterance as making a proposal with respect to actions or beliefs that should be adopted. In this paper, we discuss proposals for beliefs and focus on situations where there are (potential) conflicts between the system and the  Chu-Carroll and Carberry Response Generation in Planning Dialogues user regarding their beliefs about the domain. The paper addresses the following main issues: 1) the use of a recursive Propose-Evaluate-Modify cycle for modeling collaborative activity, 2) initiation of information-sharing subdialogues in situations where the system's existing knowledge is not sufficient to make an informed decision about the acceptance of a user proposal, 3) the process for selecting an appropriate information-sharing strategy based on the system's private knowledge about the domain and about the user, 4) initiation of collaborative negotiation subdialogues when a detected conflict is relevant to the task at hand, 5) the process for selecting the aspect to address during conflict resolution when multiple conflicts arise, and 6) the process for selecting appropriate evidence to justify the system's claims. Our implemented system, CORE (COnflict REsolver), produces responses in a university course advisement domain, where the system plays the role of an advisor who is helping a student develop a plan to achieve her domain goal. 1 The system is mutually presumed to have greater expertise in some aspects of the domain (for example, the system is presumed to be an authority on requirements for degrees but to have less certain knowledge about other aspects such as individual professor's sabbatical plans), while the user is assumed to be more knowledgeable about his particular likes and dislikes.</Paragraph>
  </Section>
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