Temporal Contexts for Discourse Representation: An Extension of the Conceptual Graph Approach (original) (raw)

Algorithms for analysing the temporal structure of discourse

Proceedings of the seventh conference on European chapter of the Association for Computational Linguistics -, 1995

We describe a method for analysing the temporal structure of a discourse which takes into account the effects of tense, aspect, temporal adverbials and rhetorical structure and which minimises unnecessary ambiguity in the temporal structure• It is part of a discourse grammar implemented in Carpenter's ALE formalism. The method for building up the temporal structure of the discourse combines constraints and preferences: we use constraints to reduce the number of possible structures, exploiting the HPSG type hierarchy and unification for this purpose; and we apply preferences to choose between the remaining options using a temporal centering mechanism• We end by recommending that an underspecified representation of the structure using these techniques be used to avoid generating the temporal/rhetorical structure until higher-level information can be used to disambiguate. the temporal component were to yield a detailed representation of the temporal structure of the discourse, taking into account the effect of tense, aspect and temporal expressions while at the same time minimising unnecessary ambiguity in the temporal structure. The method combines a constraint-based approach with an approach based on preferences: we exploit the HPSG type hierarchy and unification to arrive at a temporal structure using constraints placed on that structure by tense, aspect, rhetorical structure and temporal expressions, and we use the temporal centering preferences described by (Kameyama et al., 1993; Poesio, 1994) to rate the possibilities for temporal structure and choose' the best among them. The starting point for this work was Scha and Polanyi's discourse grammar (Scha Polanyi 1988; Priist et al 1994). For the implementation we extended the HPSG grammar (Pollard and Sag, 1994) which Gerald Penn and Bob Carpenter first encoded in ALE (Carpenter, 1993). This paper will focus on our temporal processing algorithm, and in particular on our analysis of narrative progression, rhetorical structure, perfects and temporal expressions•

Temporal Structure of Discourse

1992

In this paper discourse segments are defined and a method for discourse segmentation primarily based on abduction of temporal relations between segments is proposed. This method is precise and computationally feasible and is supported by previous work in the area of temporal anaphora resolution. I I)efinition of the rhetorical relation motivation [15]. ACTES DE COLING-92, NANTES, 23-28 hO'dT 1992 3 3 1 PROC. OF COLING-92, NANTES, AUO. 23-28, 1992

On representing the temporal structure of a natural language text

Proceedings of the 14th conference on Computational linguistics -, 1992

A proposal to deal with tenses in the framework of Discourse Representation Theory is presented, ms it has been implemented for a fragment at the IMS for the project LILOG. It is based on the theory of tenses of H. Kamp and Ch. Rohrer. The system uses tile tense and aspect information, the information about the temporal discourse structure of tile preceding text stored in a specific list of possible reference times, and background knowledge. These types of information interact in order to choose a suited temporal anchor for the event of a new sentence. With respect to extended texts, choosing the right reference time for a new event is a problem which has been largely neglected in the literature.

Modelling Structures for Situated Discourse

Dialogue & Discourse, 2020

This paper describes a corpus of situated multiparty chats developed for the STAC project (Strategic Conversation, ERC grant n. 269427). and annotated for discourse structure in the style of Segmented Discourse Representation Theory (SDRT; Asher & Lascarides,2003). The STAC corpus is not only a rich source of data on strategic conversation, but also the first corpus that we are aware of that provides discourse structures for multiparty dialogues situated within a virtual environment. The corpus was annotated in two stages: we initially annotated the chat moves only, but later decided to annotate interactions between the chat moves and non-linguistic events from the virtual environment. This two-step procedure has allowed us quantify various ways in which adding information from the nonlinguistic context affects dialogue structure. In this paper, we look at how annotations based only on linguistic information were preserved once the nonlinguistic context was factored in. We exp...

Representing Discourse in Context

Handbook of Logic and Language, 1997

This article gives a survey of Discourse Representation Theory (DRT), including recent developments, and with an emphasis on logical issues. Discourse representation structures are de ned, and various prespectives on their static and dynamic meaning are discussed. This discussion leads to the study of the process of merging representation structures, a process which can be viewed as a strategy for m e m o ry management. Next, a toy example fragment of English is presented, with a compositional DRT semantics. The nal sections are devoted to the treatment of quanti cation and of tense and aspect.

Representing events and discourse

2006

In [HKL00] (henceforth HKL), Hamm, Kamp and van Lambalgen declare “there is no opposition between formal and cognitive semantics,” notwithstanding the realist/mentalist divide. That divide separates two sides Jackendoff has (in [Jac96], following Chomsky) labeled E(xternalized)-semantics, relating language to a reality independent of speakers, and I(nternalized)-semantics, revolving around mental representations and thought. Although formal semanticists have (following David Lewis) traditionally leaned towards E-semantics, it is reasonable to apply formal methods also to I-semantics. This point is made clear in HKL via two computational approaches to natural language semantics, Discourse Representation Theory (DRT, [KR93]) and the Event Calculus (EC) presented in [LH05]. In this short note, I wish to raise certain questions about EC that can be traced to the applicability of formal methods to E-semantics and I-semantics alike. These opposing orientations suggest different notions of...

Prétexte: A Generator for the Expression of Temporal Information

1993

In this paper we present a method for generating French texts conveying temporal information. This method integrates the Discourse Representation Theory (DRT) and the Systemic Grammar Theory. First, we show how the DRT is used to represent temporal information. We then show how this formalism is used to represent the temporal localization expressed by temporal adverbial phrases. Finally, we give a description of how this representation of adverbial phrases can be translated into a syntactic form, using Systemic Grammar Theory. Prétexte, our implementation of this method, is able to generate a great variety of temporal adverbial phrases.

Knowledge Representation for Human-machine Interaction

The paper describes a computational model that we are implementing in an experimental dialogue system. Conversation process is modelled where one participant is trying to influence his/her partner to agree to do an action. Our goal is to model natural dialogue where computer as a dialogue participant follows norms and rules of human-human communication. We have worked on different aspects of developing a model of dialogue, including its computer realisation in the lines of BDI model. The main specific traits of our model are: 1) taking into account the "naïve" common-sense reasoning as the basis of dialogue, 2) modelling dialogues where the goal of the initiator is to impose the partner to do a certain action. In the paper we concentrate on the use of frames as the knowledge representation formalism in the dynamic context of dialogue. As a practical realisation of the model we have in view a computer program which we call communication trainer.

A Formalism for Temporal Annotation and Reasoning of Complex Events in Natural Language

This work has been developed with the motivation of defining a formalism (OntoTimeFL) for annotating complex events in natural language texts and applying to the items annotated several types of axioms and rules for temporal reasoning. In part, OntoTimeFL is a conceptualization of TimeML formalism, where the basic concepts of annotation by an ontological form have been represented. In addition, OntoTimeFL introduces new constructs for the annotation that mainly concern three complex events: narrative, intentional, and causal. OntoTimeFL entities have been defined as classes of a formal ontology; a methodological choice for facilitating automatic annotation processes to reuse existing axiomatics in the research of temporal reasoning, and facilitate the creation of new ones (some proposals in this paper).

A SY}~ACTIC APPROACH TO DISCOURSE SEMANTICS

A correct structural analysis of a discourse is a prerequisite for understanding it. This paper sketches the outline of a discourse grammar which acknowledges several different levels of structure. This gram~nar, the "Dynamic Discourse Model", uses an Augmented Transition Network parsing mechanism to build a representation of the semantics of a discourse in a stepwise fashion, from left to right, on the basis of the semantic representations of the individual clauses which constitute the discourse. The intermediate states of the parser model the intermediate states of the social situation which generates the discourse.