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<Paper uid="C88-2130">
  <Title>Directing the Generation of Living Space Descriptions</Title>
  <Section position="2" start_page="0" end_page="626" type="intro">
    <SectionTitle>
1. Introduction
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    <Paragraph position="0"> At this point in research on natural language generation, it is important to select problems that will clarify what is at issue in the larger phenomena under study, while at the same time being small enough to yield principled results in a reasonable amount of time. To build on what the field has already accomplished, the problem must involve the generation of motivated discourses--rather than isolated test sentences--and should be based on a corpus of real text. Furthermore, since a computational treatment of a generation problem should include a fully programmed underlying conceptual model to facilitate experiments, and since the representation used in that model will invariably play a crucial role in any theory, part of the research is building the model and designing the representation.</Paragraph>
    <Paragraph position="1"> This means that to be tractable the problem should not require expert knowledge or be overly large.</Paragraph>
    <Paragraph position="2"> Support for this work was provided in part by the Defense Advanced Research Projects Agency under contract number N00014-87-K0238, and by Rome Air Development Center under contract number AF3060281-C-0169, task number 174398, both at the University of Massachusetts.</Paragraph>
    <Paragraph position="3">  Living space descriptions fit these demands neatlydeg They are single-speaker monologues, allowing us to ignore issues of turn-taking strategies or interpreting an interlocutor's intentions. The task is something everyone seems to be able to do, but it is not such an everyday occurrence that it has become formulaic: it is likely that people are actively constructing what they are saying. Affective and abstract information is minimal and, to a first approximation, can be safely factored out of a corpus, reducing the potential complexity of the conceptual model in living space descriptions. This simplicity has allowed us to concentrate on our primary concerns: (a) understanding the relationship between the organization of a conceptual model and descriptive strategies, (b) determining the influence of these strategies on the discourse structure of a text, and (e) taking an initial look at issues in lexical choice in a familiar domain.</Paragraph>
    <Paragraph position="4"> At the time this paper is written, we have finished the first phase of our research. We have collected and carefully transcribed a corpus of seven different people's descriptions of the same, single-story house (the residence of one of the authors). A program model of this house, as these people appear to view it, has been developed, along with a set of strategies and meta-strategies for generating some of the living space descriptions that emerged from our analysis of the corpus. This paper presents our representation, some of the strategies we have identified and their application in mimicking I a segment from our corpus, and our  * treatment of some linguistic issues in choosing words and constructions.</Paragraph>
    <Paragraph position="5"> 2. Background and approach  The s~;minal work in living space descriptions is Charlotte Linde's 1974 dissertation. Linde's data consisted of 72 descriptions of apartments elicited in inte~ciews on the quality of life in New York City. She found that the great majority of speakers organize their descriptions as an imaginary &amp;quot;tour&amp;quot; of the apartment. The spatial relationships among the rooms can be expressed by describing how one might make one's way from each room to the next. Such a tour is of course constrained by the position of the actual routes through the apartmentdeg Linde proposed a model in terms of a phrase st~'ucture network in which the terminal nodes were rooms and vectors of various categories.</Paragraph>
    <Paragraph position="6"> Veronika Ullmer-Ehrich, (1982) extended the discussion to descriptions of individual dormitory rooms, again embedded in longer interviews. The descriptions she collected focused on the spatial relationships among the rooms' furnishings. She found, as one might expect, that imaginary movement was less usual here, since the speaker can typically &amp;quot;see&amp;quot; everything to be mentioned from a single point of view. As in Li~de's apartment descriptions, physical proximity has a strong influence on the order in which objects are introduced; Ullmer-Ehrich refers to the result as an imaginm'y &amp;quot;gaze tour&amp;quot; around the walls. (Our own informants tended to give the contents of the rooms as well as their spatial relations to each other, letting us see both kinds of strategies in action.) Linde's and Ullmer-Ehrich's treatments were descriptive. Ours attempts to model the motivations behind the texts. Our aim is to conslxuct a computer program that can reproduce our data and, further, produce variations on it. If simple variations on the parameters of our model still produce realistic texts, then we will have a basis for claiming that it could be a candidate explanatory model of the processing that underlies human behavior in this task.</Paragraph>
    <Paragraph position="7"> Our implementation, APT, is composed of a knowledge base consisting of interconnected first-class objects that reconstruct the living space, strategies which traverse the knowledge base constructing descriptions, meta-strategies which choose among the strategies each time a new strategy is needed, and mapping rules between APT's knowledge structures and the re;dization component's knowledge structures.</Paragraph>
    <Paragraph position="8"> t Living space descriptions are a small enough subject area that it is worth trying to develop a treatrnent with enough articulations in its mechanisms to potentially account for every detail of what people actually say---hence &amp;quot;mimic&amp;quot;. There may well be a vast amount of arbitrariness in the decisions people make; but the pressure to explain the fine structure of their utterances, not just to gloss over it by producing something &amp;quot;comparable&amp;quot; but more regular, should lead to stronger, more interesting theories.</Paragraph>
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