ISO 24617-8:2016 establishes the representation and annotation of local, "low-level" discourse relations between situations mentioned in discourse, where each relation is annotated independently of other relations in the same discourse.
ISO 24617-8:2016 provides a basis for annotating discourse relations by specifying a set of core discourse relations, many of which have similar definitions in different frameworks. To the extent possible, this document provides mappings of the semantics across the different frameworks.
ISO 24617-8:2016 is applicable to two different situations:
- for annotating discourse relations in natural language corpora;
- as a target representation of automatic methods for shallow discourse parsing, for summarization, and for other applications.
The objectives of this specification are to provide:
- a reference set of data categories that define a collection of discourse relation types with an explicit semantics;
- a pivot representation based on a framework for defining discourse relations that can facilitate mapping between different frameworks;
- a basis for developing guidelines for creating new resources that will be immediately interoperable with pre-existing resources.
With respect to discourse structure, the limitation of this document to specifications for annotating local, "low-level" discourse relations is based on the view that (a) the analysis at this level is what is well understood and can be clearly defined; (b) further extensions to represent higher-level, global discourse structure is possible where desired; and (c) that it allows for the resulting annotations to be compatible across frameworks, even when they are based on different theories of discourse structure.
As a part of the ISO 24617 semantic annotation framework ("SemAF"), the present DR-core standard aims to be transparent in its relation to existing frameworks for discourse relation annotation, but also to be compatible with other ISO 24617 parts. Some discourse relations are specific to interactive discourse, and give rise to an overlap with ISO 24617 Part 2, the ISO standard for dialogue act annotation. Other discourse relations relate to time, and their annotation forms part of ISO 24617-1 (time and events); still other discourse relations are very similar to certain predicate-argument relations ("semantic roles"), whose annotation is the subject matter of ISO 24617-4. Since the various parts are required to form a consistent whole, this document pays special attention to the interactions of discourse relation annotation and other semantic annotation schemes (see Clause 8).
ISO 24617-8:2016 does not consider global, higher-level discourse structure representation which involves linking local discourse relations to form one or more composite global structures.
ISO 24617-8:2016 is, moreover, restricted to strictly semantic relations, to the exclusion of, for example, presentational relations, which concern the way in which a text is presented to its readers or the way in which speakers structure their contributions in a spoken dialogue.