{ "paper_id": "C86-1008", "header": { "generated_with": "S2ORC 1.0.0", "date_generated": "2023-01-19T13:14:36.200734Z" }, "title": "A TWO-LEVEL DI~ REPRESENTATION 1", "authors": [ { "first": "Giacomo", "middle": [], "last": "Ferrari", "suffix": "", "affiliation": { "laboratory": "", "institution": "University of Pisa", "location": {} }, "email": "" }, { "first": "Ronan", "middle": [], "last": "Reilly", "suffix": "", "affiliation": { "laboratory": "Educational Research Centre St Patrick's College", "institution": "", "location": { "settlement": "Dublin" } }, "email": "" } ], "year": "", "venue": null, "identifiers": {}, "abstract": "In this paper a two level dialogue representation system is presented\u00b0 It is intended to recognize the structure of a large range of dialogues including some nonverbal communicative acts which may be involved in an interaction.", "pdf_parse": { "paper_id": "C86-1008", "_pdf_hash": "", "abstract": [ { "text": "In this paper a two level dialogue representation system is presented\u00b0 It is intended to recognize the structure of a large range of dialogues including some nonverbal communicative acts which may be involved in an interaction.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "Abstract", "sec_num": null } ], "body_text": [ { "text": "It provides a syntactic description of a dialogue which can be expressed in terms of re-writing rules.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "", "sec_num": null }, { "text": "The semantic level of the proposed representation system is given by the goal and subgoal structure underlying the dialogue syntactic units.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "", "sec_num": null }, { "text": "Two types of goal are identified; goals which relate to the content of the dialogue, and those which relate to cormaunicating the content\u00b0 i. INTRODUCTION Research on computational modelling of discourse has highlighted some important aspects of hun~an dialogic communication.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "", "sec_num": null }, { "text": "In some cases (Reichman, 1984) , a structural description of linguistic communication has been attempted altklough not for proper dialogue. What is required is a structural description identifying a corresponding set of con~nunicative acts which can be confined in a fixed pattern, to form higher level communication act categories or dialogue constituents.", "cite_spans": [ { "start": 14, "end": 30, "text": "(Reichman, 1984)", "ref_id": null } ], "ref_spans": [], "eq_spans": [], "section": "", "sec_num": null }, { "text": "The importance of such a structural description, if attained, is that it would make possible an axiomatic theory of dialogue, embedding rhetorical patterns, focusing, and focus shifting.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "", "sec_num": null }, { "text": "A possible basis for such a structural description is Burton's (1981) taxonomy of communication acts, with some modifications. Such a formalization of dialogue, however, is a fully syntactic one which needs to be augmented with some semantics.", "cite_spans": [ { "start": 54, "end": 69, "text": "Burton's (1981)", "ref_id": null } ], "ref_spans": [], "eq_spans": [], "section": "", "sec_num": null }, { "text": "Our assumption is that dialogue constituents have a semantic interpretation in terms of goals and subgoals.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "", "sec_num": null }, { "text": "A theoretical frame for a dialogue classification system based on these assunptions is being developed with the aim of providing a coherent basis for the computational modelling of dialogue.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "", "sec_num": null }, { "text": "The final aim of our project is, in fact the design and implementation of a computational dialogic interaction system, with the ability to recover fr~n communication failure.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "", "sec_num": null }, { "text": "The syntactic level of a dialogue description system has to meet three requirements:", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "STRUCZURAL DESCRIPTION", "sec_num": "2." }, { "text": "(a) It must consist of a model whose generality makes it applicable to both person-person and 1This research was supported in part by the ESPRIT progranme of the CEC under contract AIP P527.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "STRUCZURAL DESCRIPTION", "sec_num": "2." }, { "text": "person-machine dialogues, irrespective of the socio-institutional disposition of any speaker/user. (c) It must be capable of \"naming\" the units which compose the dialogue exchanges, i.eo identifying an utterance as both of a particular type and playing a cez%ain role in a particular exchange.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "STRUCZURAL DESCRIPTION", "sec_num": "2." }, { "text": "The dialogue units taxonomy proposed by Burton (].981) seems to satisfy these requirements. According to her analysis systen[ we distinguish four hierarchically related levels: the interaction~ which is the largest unit; the transaction; the exchange; the move; and the act.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "STRUCZURAL DESCRIPTION", "sec_num": "2." }, { "text": "An interaction consists of a number of transactions, a transaction consists of a number of exchanges, and so on. ~e smallest interactive unit in this system is the move. A move can consist of a number of linguistic and non-linguistic \"acts\" which are realised either as utterances or physical actions.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "STRUCZURAL DESCRIPTION", "sec_num": "2." }, { "text": "An act is a way of classifying utterances which occur in a conversational move. The act is a level above that of the utterance, and a move can consist of a number of acts. For example, ~le following is an opening n~veby a teacher in a classroom dialogue consisting of two acts (in brackets):", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "ACTS", "sec_num": "2.1" }, { "text": "T: those letters have a special name (Starter) do you know what it is (Elicitation)", "cite_spans": [ { "start": 37, "end": 46, "text": "(Starter)", "ref_id": null } ], "ref_spans": [], "eq_spans": [], "section": "ACTS", "sec_num": "2.1" }, { "text": "Most acts are realisedby a wide range of utterance types\u00b0 For example, the act called 'starter' can be realised by either a statement, question, conraand, or a moodless item.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "ACTS", "sec_num": "2.1" }, { "text": "we distinguish the following 15 acts, marker, summons, silent stress, starter, metastatements, conclusion, informative, elicitation, directive, comment, accept, reply, react, acknowledge, preface, prompt, null.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "ACTS", "sec_num": "2.1" }, { "text": "Their definition is always given in terms of both linguistic structure and function. Thus, for instance, the starter act, whose structure has been described above, has the function of providing information about, directing attention to, or thought towards an area, in order to increase the likelihood of making a correct response to the subsequent initiation. An informative act has the structure of a statea~nt and serves the function of providing information.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "ACTS", "sec_num": "2.1" }, { "text": "Some of these acts are more directly relevant to the problem of analysing person machine dialogues than others.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "ACTS", "sec_num": "2.1" }, { "text": "However, together they provide a broad fran~work, incorporating both verbal and non-verbal aspects of dialogue, within which we can situate a detailed analysis of the more relevant acts.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "ACTS", "sec_num": "2.1" }, { "text": "At a higher level seven types of move are recognized:", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "MOVES", "sec_num": "2.2" }, { "text": "delineating, sketching, opening, supporting, challenging, bound-opening, and reopening.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "MOVES", "sec_num": "2.2" }, { "text": "Moves are the basic units of a dyadic exchange and can consist of a ntnnber of acts. We will define the various moves in a semi-formal manner. 'fhe formalism is a type of context-sensitive grammar. If an element is enclosed in { ] it indicates that the item is optional.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "MOVES", "sec_num": "2.2" }, { "text": "The symbol I indicates that the elements it separates are alternatives.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "MOVES", "sec_num": "2.2" }, { "text": "If an element is enclosed in < > it indicates that the symbol is non-terminal and requires further expansion.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "MOVES", "sec_num": "2.2" }, { "text": "The following is the formal description of a sketching move: := [] {] :=marker I su~nons := starter := metastatement I conclusion Similar descriptions are also given for the other moves.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "MOVES", "sec_num": "2.2" }, { "text": "In addition to these standard conventions we adopt a special convention to illustrate the effects of context. ~is takes the form:", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "MOVES", "sec_num": "2.2" }, { "text": "C[ <~g2>] := expansion", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "MOVES", "sec_num": "2.2" }, { "text": "Where C is a function which, when evaluated, expands subject to something being true of . For example, we might want to restrict the expansion of ~ only those situation in which has already occurred as an act in the previous move. This can be accomplished by an appropriately defined C function\u00b0 2.3 EXCHANGES Sequences of moves compose an exchange. According to Burton two types of exchange are distinguished: explicit boundary (EB) exchanges and conversational (C) exchanges.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "MOVES", "sec_num": "2.2" }, { "text": "Explicit boundary exchanges occur, as their name suggests, at the boundary of transactions.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "MOVES", "sec_num": "2.2" }, { "text": "They can include delineating and/or sketching moves which must be supported by another speaker.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "MOVES", "sec_num": "2.2" }, { "text": "exchanges consist of chains of opening, challenging and/or supporting moves. Th~ numbers, the-repetition factors themselves, can range from 0 upwards. However, when n is 0, m and 1 are also 0. This arr~]gement allows ~s to ge-nerat~ a different bound-opening/supporting pattern for each m.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "Conversational", "sec_num": null }, { "text": "Transactions and interactions are the final two levels of the classification hierarchy. Transactions consist of patterns of exchanges, and interactions consist of unordered strings of transactions.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "TRANSACTIONS AND INTERACTIONS", "sec_num": "2.4" }, { "text": "Transactions have the following form:", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "TRANSACTIONS AND INTERACTIONS", "sec_num": "2.4" }, { "text": " := {} C[ ] {C[ ] {C[ ]}l} m", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "TRANSACTIONS AND INTERACTIONS", "sec_num": "2.4" }, { "text": "The C function in this case expands its second argument if the first argument, a move, is the initiator of the C-exchange.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "TRANSACTIONS AND INTERACTIONS", "sec_num": "2.4" }, { "text": "Finally interactions t~ke the form:", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "TRANSACTIONS AND INTERACTIONS", "sec_num": "2.4" }, { "text": " := 1", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "TRANSACTIONS AND INTERACTIONS", "sec_num": "2.4" }, { "text": "The following two assumptions form the basis for a pairing of a dialogue planning mechanism with elexents of the clialogue description system: dialogue participants always have two cooperating types of goals, substantive real life goals (Sgoals), which determine \"what to say\", and linguistic/communicative goals (C-goals), which determine \"how to say it\".", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "%~E COMV~]NICATIVE COMPONENT", "sec_num": "3." }, { "text": "No relation of necessity seems to hold between them. In fact, in most cases there are many different ways of expressing the same goal.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "%~E COMV~]NICATIVE COMPONENT", "sec_num": "3." }, { "text": "it is possible to identify hierarchical relations between goals and subgoals both for substantive and communicative goals. However, in the high level dialogue description system units S-goals see/~1 to be more important, while at the low levels C-goal seem to prevail.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "%~E COMV~]NICATIVE COMPONENT", "sec_num": "3." }, { "text": "The highest level of the discourse structure is the transaction. Given that the dialogue as a whole is a means of effecting the high-level goals of one or other of the participants, we can functionally define transaction as the unit of dialogue concerned with effecting these high-level goals.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "%~E COMV~]NICATIVE COMPONENT", "sec_num": "3." }, { "text": "At the highest lewi.~l of the dialogue's goal structure the dominant goals motivating the transaction are those concerned with the substance of the dialogue, not the means by which the substance is conveyed.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "%~E COMV~]NICATIVE COMPONENT", "sec_num": "3." }, { "text": "As we move down this hierarchy it is possible to discern a bifurcation of goals into one group concerned with the substance of the dialogue, and the other concerned with communication of this substance.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "%~E COMV~]NICATIVE COMPONENT", "sec_num": "3." }, { "text": "These are the Sgoals and C-goals (or more properly, S and C subgoals) mentioned above.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "%~E COMV~]NICATIVE COMPONENT", "sec_num": "3." }, { "text": "A transaction is always motivatedby a general goal such as seek information, make a train journey (Allen, 1982) , make a reservation.", "cite_spans": [ { "start": 98, "end": 111, "text": "(Allen, 1982)", "ref_id": null } ], "ref_spans": [], "eq_spans": [], "section": "%~E COMV~]NICATIVE COMPONENT", "sec_num": "3." }, { "text": "The social context, for example the relation between speaker and hearer or simply a social convention, can suggest rhetorical choices.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "%~E COMV~]NICATIVE COMPONENT", "sec_num": "3." }, { "text": "Among these might be the direct stating of the general goal, the indirect revelation ofthe general goal by several related questions, the questioning of a system's general capabilities before asking, and so on.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "%~E COMV~]NICATIVE COMPONENT", "sec_num": "3." }, { "text": "Essentially, exchanges can be thought of as the topic-bearing elements of the dialogue.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "%~E COMV~]NICATIVE COMPONENT", "sec_num": "3." }, { "text": "New topics are introduced by either an EB-exchange (explicit boundary), a C-exchange (conversational) with an opening move as its first move, or a C-exchange with a challenge as its first move.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "%~E COMV~]NICATIVE COMPONENT", "sec_num": "3." }, { "text": "Topics that have been discussed prior to the most recent challenge are re-introducedby a C-exchange with a re-opening move as its first move.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "%~E COMV~]NICATIVE COMPONENT", "sec_num": "3." }, { "text": "Topics that have been discussed less recently are re-introduced by means of an EB-exchange containing a sketching move.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "%~E COMV~]NICATIVE COMPONENT", "sec_num": "3." }, { "text": "There is, therefore, a strong connection between the exchange structure of the transaction and the pattern of topic-shifts in the dialogue. These topic-shifts, in turn, are related to the conversant's shifting goal structure. This is especially true in task-oriented dialogues, where the component operations of the task are mirrored in the topic structure of the dialogue (Grosz, 1981) . A general goal can be, therefore, split into a sequence of subgoals bof/n because the task consists in reality of a sequence of subtasks (Grosz, 1981) and because of rhetorical reasons.", "cite_spans": [ { "start": 373, "end": 386, "text": "(Grosz, 1981)", "ref_id": null }, { "start": 526, "end": 539, "text": "(Grosz, 1981)", "ref_id": null } ], "ref_spans": [], "eq_spans": [], "section": "%~E COMV~]NICATIVE COMPONENT", "sec_num": "3." }, { "text": "This gives a very special status to exchanges in our classification system.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "%~E COMV~]NICATIVE COMPONENT", "sec_num": "3." }, { "text": "A transaction is in fact, divided into several exchanges determined either by the structure of the task to be carried out, or by rhetorical considerations, or by both. In particular, we should distinguish between two types of exchange: -a subtask exchange, which aims at reaching some substantive subgoal an instrumental exchange, which aims at attaining some communicative (sub)goal, such as introducing the terms of the conversation, or clarifying some unclear substantive goal or subgoal.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "%~E COMV~]NICATIVE COMPONENT", "sec_num": "3." }, { "text": "Every exchange is conloosed of moves and is, in most cases, opened by some form of topic shifting move and closed by a concluding move. Other sabcategories of exchanges can be found. However, a pattern of moves is associated with every exchange. At this level different rhetorical choices (motivated by C-goals) may appear in the form of different distributions of instrumental or nonclarifying exchanges within a transaction.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "%~E COMV~]NICATIVE COMPONENT", "sec_num": "3." }, { "text": "The Sgoals of an exchange can be computed from the interpretation of the utterances comprising it, utilising some notion of general focus (Sidner, 1979) .", "cite_spans": [ { "start": 138, "end": 152, "text": "(Sidner, 1979)", "ref_id": null } ], "ref_spans": [], "eq_spans": [], "section": "%~E COMV~]NICATIVE COMPONENT", "sec_num": "3." }, { "text": "At a lower level, the goals that motivate the moves are drawn equally from S-goals and C-goals. At the move level, the S-goal structure becomes less relevant to the sequence of moves. Moves are mostly rhetorical elements. They signal the pushing to a (new) topic (topic shifting and topic re-introducing moves), the continuation of a topic (topic 44 maintaining moves), and the popping of a topic (nonintroduction).", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "%~E COMV~]NICATIVE COMPONENT", "sec_num": "3." }, { "text": "Pushing and popping are the opening and closing moves of an exchange. The coherence of the topic is to be expected within an exchange and should be perhaps checked from one move to the other. A topic shift is in itself a pushing move. The notion of topic probably coincides with the notion of focused goal.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "%~E COMV~]NICATIVE COMPONENT", "sec_num": "3." }, { "text": "Moves serve as syntactic components of exchanges and every move is a step in a linguistic goal structure. Therefore, every exchange consists of a pattern of moves representing the communicative choices of the dialogue participants. In some cases, there is a correspondence between the S-goal associated with an exchange and some move (challenge).", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "%~E COMV~]NICATIVE COMPONENT", "sec_num": "3." }, { "text": "Also a communicative adherence between one move and the following should hold.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "%~E COMV~]NICATIVE COMPONENT", "sec_num": "3." }, { "text": "Coherence means that the topic must be roughly the same, while adherence moans that the given move canbe followed only by a specific set ofmoves.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "%~E COMV~]NICATIVE COMPONENT", "sec_num": "3." }, { "text": "Finally, an act is a limited linguistic act, uttered to effect very local communicative/rhetoric goals. In a dialogue most moves consists of a single act, but this does not. always hold. A distinction can be made at the act level between acts which are drawn from a limited class of utterances, and acts which are not limited in this way.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "%~E COMV~]NICATIVE COMPONENT", "sec_num": "3." }, { "text": "We will call these closed and open classes, respectively.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "%~E COMV~]NICATIVE COMPONENT", "sec_num": "3." }, { "text": "Most of the closed class items are associated with acts which subserve C-goals rather than S-goals. This is not too surprising since the items from the closed class do not usually convey substantive information but usually serve as go-ahead signals in a dialogue. Whereas the primary function of open class items is to convey task-relevant information.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "%~E COMV~]NICATIVE COMPONENT", "sec_num": "3." }, { "text": "From the previous paragraph it has been clear that there is a different distribution of S and C-goals along the hierarchy of dialogue units. In particular, higher level units are more related to S-goals, while low level units are connected to Cgoals.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "SYNTACTIC STRUCTURE AND GOAL STRUCTURE", "sec_num": "4." }, { "text": "The model presented is intended to serve mainly descriptive and representational purposes. No definition is given of the process of inference of the goal structure from the syntactic structure of dialogue. However it is possible to imagine that such a process rely, among others, on -the functions assigned to ~ialogue subunits -the actions mentioned in any specific utterance.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "SYNTACTIC STRUCTURE AND GOAL STRUCTURE", "sec_num": "4." }, { "text": "The advantages of the proposed dialogue description system are the following:", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "CONCLUSIONS AND PERSPECTIVES", "sec_num": "5." }, { "text": "-the design of a grammar for the description of dialogue units and subunits is madepossible;", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "CONCLUSIONS AND PERSPECTIVES", "sec_num": "5." }, { "text": "the distinction between S-and C-goals allows the treata~nt of possible interrupt and clarification subdialogues in the same frame as the goal directed parts of the dialogue;", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "CONCLUSIONS AND PERSPECTIVES", "sec_num": "5." } ], "back_matter": [ { "text": "will be devoted to the specification of a more detailed grammar of exchanges and moves, and to the establishing of a stricter correspondence between more types of goals. However, a still more important point to be clarified is the specification of the for1~al devices by which the semantic (goal) structure can be inferred from utterance and act elements and 'raised' to the higher dialogue units. Sinclair, J., & Coulthard, M. (1975) . Towards an ~alysis of discourse. London, England : Oxford University Press.", "cite_spans": [ { "start": 412, "end": 434, "text": "& Coulthard, M. (1975)", "ref_id": null } ], "ref_spans": [], "eq_spans": [], "section": "Further research", "sec_num": null } ], "bib_entries": {}, "ref_entries": { "FIGREF0": { "uris": null, "num": null, "type_str": "figure", "text": "(b) It must be capable of describing in terms of communication concepts the i~teractive nature of dialogue exchanges." }, "FIGREF1": { "uris": null, "num": null, "type_str": "figure", "text": "move>}l]m] n] := ll The superscripts i, m, and n represent sets of numbers of repetitions ~ Where [\" contains m numbers, m contains n numbers v and n ~onsists o~ just one ~umber." } } } }