SIST-TS ISO/TS 24617-5:2018

TECHNICAL ISO/TS
SPECIFICATION 24617-5
First edition
2014-03-01
Language resource management —
Semantic annotation framework
(SemAF) —
Part 5:
Discourse structure (SemAF-DS)
Gestion de ressources langagières — Cadre d’annotation sémantique
(SemAF) —
Partie 5: Structures de discours (SemAF-DS)
Reference number
ISO/TS 24617-5:2014(E)
©
ISO 2014

---------------------- Page: 1 ----------------------
ISO/TS 24617-5:2014(E)

COPYRIGHT PROTECTED DOCUMENT
© ISO 2014
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form
or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior
written permission. Permission can be requested from either ISO at the address below or ISO’s member body in the country of
the requester.
ISO copyright office
Case postale 56 • CH-1211 Geneva 20
Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail copyright@iso.org
Web www.iso.org
Published in Switzerland
ii © ISO 2014 – All rights reserved

---------------------- Page: 2 ----------------------
ISO/TS 24617-5:2014(E)

Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Overview . 2
5 Segment structure . 3
6 Content structure . 4
7 Mapping between segment and content structures . 7
8 Concluding remarks .16
Bibliography .17
© ISO 2014 – All rights reserved iii

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ISO/TS 24617-5:2014(E)

Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www.iso.org/patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation on the meaning of ISO specific terms and expressions related to conformity
assessment, as well as information about ISO’s adherence to the WTO principles in the Technical Barriers
to Trade (TBT) see the following URL: Foreword - Supplementary information
The committee responsible for this document is ISO/TC 37, Terminology and other language and content
resources, Subcommittee SC 04, Language resource management.
ISO 24617 consists of the following parts, under the general title Language resource management —
Semantic annotation framework:
— Part 1: Time and events (SemAF-Time, ISO-TimeML)
— Part 2: Dialogue acts (SemAF-DA)
— Part 4: Semantic roles (SemAF-SR)
— Part 5: Discourse structures (SemAF-DS)
— Part 6: Principles of semantic annotation (SemAF-Basics)
— Part 7: Spatial information (ISO-Space)
— Part 8: Semantic relations in discourse (SemAF-DRel)
iv © ISO 2014 – All rights reserved

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ISO/TS 24617-5:2014(E)

Introduction
Discourse structures play an essential role in the production and analysis of the syntactic, semantic,
and pragmatic features of text, speech, and other types of discourse. This Technical Specification is
a basis both for the annotation, generation and translation (among other processes) of these types of
discourses and of the syntactic, semantic, and pragmatic features derived from them. Note that discourse
structures underlie not only verbal communication (whether spoken, written, or signed) but also non-
verbal discourse (such as a silent video).
The annotation scheme provided here specifies discourse structures that consist of segment structures
and content structures. It also specifies the mappings between these two structures; the mappings are
described by the annotations of discourse segments in texts or some other modalities. In this context,
on the one hand, segment structures are spatiotemporal relations that hold between surface segments
(such as words, phrases, clauses, sentences, and video scenes) and, on the other hand, content structures
are discourse relations that are established between semantic and pragmatic items. Both of these
structures can be represented by means of labelled directed graphs or sometimes simply by trees, as
standardized by LAF (ISO 24612:2012) and SynAF (ISO 24615:2010).
This scheme also provides a common, language-neutral pivot for the interoperation among diverse
formats of discourse structures of various types of document, and can be applied to the generation of
linguistic and non-linguistic expressions. For example, if the discourse structures of speech and other
linguistic data contained in motion pictures are fitted to this scheme, multilingual subtitles for these
pictures can be generated at a reduced cost by means of a standardized tool for multilingual translation.
By the same token, this scheme can facilitate interoperability among various discourse corpora and
collaboration among researchers who use them.
© ISO 2014 – All rights reserved v

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TECHNICAL SPECIFICATION ISO/TS 24617-5:2014(E)
Language resource management — Semantic annotation
framework (SemAF) —
Part 5:
Discourse structure (SemAF-DS)
1 Scope
A discourse is a process of communication. This Technical Specification addresses how a discourse is
structured in terms of its realization/presentation and content, and shows how its dual structure can
be represented in a graph. The current specification focuses on the annotation of discourse structures
in text only, but it can be extended to discourses in other modalities.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are
indispensable for its application. For dated references, only the edition cited applies. For undated
references, the latest edition of the referenced document (including any amendments) applies.
ISO/IEC 15938-5:2003/Amd.1:2004, Information technology. Multimedia content description interface.
Part 5: Multimedia description schemes AMENDMENT 1: Multimedia description schemes extensions (MPEG-
7 MDS AMD1)
ISO 24612:2012, Language resource management — Linguistic annotation framework (LAF)
ISO 24615:2010, Language resource management — Syntactic annotation framework (SynAF)
ISO 24617-1:2012, Language resource management — Semantic annotation framework — Part 1: Time and
events (SemAF-Time, ISO-TimeML)
ISO 24617-2:2012, Language resource management — Semantic annotation framework — Part 2: Dialogue
acts
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
circumstance
entity which is an event (including dialogue act), state, process, relation, proposition, or set of these
3.2
class
unary predicate, which is a set of entities
3.3
discourse
process of communication, consisting of one or more sentences or sentence fragments
Note 1 to entry: From an abstract viewpoint, data (e.g. words, phrases, sentences, and paragraphs) representing
a communication process is regarded as a discourse. A discourse can be encoded in various media such as text,
hypertext, audio, video, and their possible combinations.
© ISO 2014 – All rights reserved 1

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ISO/TS 24617-5:2014(E)

3.4
discourse relation
semantic/pragmatic relation that holds among two or more circumstances
Note 1 to entry: Some discourse relations, such as example and part, can also hold between objects. In this
document, semantic/pragmatic relations (including discourse relations) are given in italics in the text and with a
gray background in the Figures (e.g. agent, inference, and purpose).
3.5
discourse structure
structure of discourse, comprising segment structure, content structure, and possibly other types of
structure
3.6
entity
semantic/pragmatic entity referenced in discourse, including circumstances, and objects
Note 1 to entry: An entity is represented by a node in a content structure.
3.7
object
semantic entity other than circumstance
Note 1 to entry: Objects include people, buildings, machines, ideas, and rules.
3.8
relational class
class whose instances are circumstances equivalent to relations
3.9
segment
word, phrase, clause, sentence, paragraph, section, chapter, or other partial realization of discourse
Note 1 to entry: A synonym is a ‘discourse segment’. A segment references a semantic and/or pragmatic entity,
which can be a semantic/pragmatic relation. Intrasentential segments are syntactic constituents such as words,
phrases, and clauses. Segments might or might not be continuous: this is discussed in the definition of connectives.
4 Overview
A discourse structure consists of two types of structure: segment structure and content structure. A
segment structure (extending intrasentential syntax) is a data structure that describes how a discourse
has been organized from a formal syntactic perspective. It consists of
a) a set of segments (some partial realizations of discourse), and
b) the syntactic relations holding among them.
A content structure (extending intrasentential semantics) is a data structure that describes from a
logical point of view how a discourse has been organized. It consists of
a) the set of semantic and pragmatic components referred to by the segments of a segment structure
(that is, by some segments of some discourse), and
b) the logical relations established between these semantic representations. These two structures
organize the whole structure of each discourse.
Both types of structure and content structures in particular, can be represented by means of a labelled
directed graph. Various syntactic relations in a segment structure can, for instance, be captured by a
tree (single-rooted graph). Discourse relations in a content structure can also be captured by a more
general graph: The nodes in the graph stand for semantic and pragmatic components and the edges
formalize the relations holding among them. In one way, a segment structure is to a discourse (or part of
2 © ISO 2014 – All rights reserved

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ISO/TS 24617-5:2014(E)

it) what a syntactic structure is to a sentence (or a sub-sentential component), and a content structure is
to a discourse (or part of it) what a semantic structure is to a sentence (or a sub-sentential component).
[4]
Rhetorical Structure Theory (RST) assumes that discourse has a tree-like structure that can be
regarded as an amalgamation of segment structures and content structures. Corpus annotation based
[2]
on RST considers segment structures involving markables, their annotations and, implicitly, some
sort of content structures derived from them. Other corpus annotation initiatives such as the Prague
[3] [6]
Dependency Treebank and the Penn Discourse TreeBank follow essentially the same approach. By
[1]
contrast Segmented Discourse Representation Theory (SDRT) explicitly discusses content structures
called Segmented Discourse Representation Structures (SDRSs), and with less commitment to segment
structures and the mapping thereof.
By integrating these recent practices in fields such as formal linguistics, knowledge representation and
corpus annotation, this Technical Specification provides an annotation scheme to partially specify the
segment structures and the mapping from them to their corresponding content structures. For the sake
of interoperability across different ISO standards such as LAF and SynAF, this annotation scheme has
been made interoperable with practices concerning syntax and intrasentential semantics; this mapping
from segment structures to content structures is therefore a straightforward extension of the mapping
from syntactic structures to semantic structures, as addressed in many corpora, including the Penn
[7] [5]
TreeBank (PTB) and PropBank .
As for sentences, parse trees describe their syntax, and logical forms represent their semantics. As
for discourses, however, their syntax (i.e. their formal organization) and semantics (i.e. their content
and logical organization) have been discussed in a more intertwined manner. For instance, most of the
literature such as Reference [4] has regarded discourse relations as carrying both semantic and pragmatic
information. This is inconvenient when one wants to focus on the semantic aspects of discourses, for
instance, which can be the case when dealing with hypertexts, games and so on, which lack prefixed
temporal order of presentation, and when discussing multiple (e.g. multilingual) presentations of the
same semantic content.
To distinguish the realization/presentation and the content of a discourse and to address the mapping
between them, this Technical Specification defines segment structures, content structures, and
annotations to segments (discourse units) as part of segment structures. Segment structures represent
the way in which the discourse is arranged, and consist of segments (e.g. words, phrases, clauses,
sentences, paragraphs, sections, and chapters) together with the syntagmatic organization relations
holding among them. Content structures represent the semantic and pragmatic content of discourses,
and consist of nodes and links that represent entities referenced by segments. The main goal of this
Technical Specification is to define an annotation scheme that concisely addresses segment structures,
content structures and mappings between them. In other words, each segment annotated according
to this scheme should represent a set of correspondences between segment structures and content
structures.
A major basis of this Technical Specification is ISO/IEC 15938-5:2003/Amd.1:2004. This Technical
Specification is mostly restricted to discourse structures, although the Linguistic DS also deals with
predicate-argument structures and dialogue acts.
This Technical Specification addresses both the intrasentential and intersentential aspects of segment
structures. The annotation of intrasentential aspects is compliant with ISO 24615:2010; that of both the
aspects is consistent with the other two published parts ISO 24617-1:2012 and ISO 24617-2:2012. Their
annotations and representations can be encoded according to ISO 24612:2012 as it supports labelled
directed graphs.
5 Segment structure
A segment structure of a discourse addresses its syntactic organizations. This Technical Specification
assumes that, not all, but some segment structures are represented as trees with their nodes representing
discourse segments. If segment S (as a sequential data such as text and speech) has directed descendants
(called ‘daughters’), S is their concatenation. For instance, Figure 1 represents the segment structure of
a discourse ‘Tom left. It was late.’ which consists of two daughters ‘It was late.’ and ‘Tom left.’
© ISO 2014 – All rights reserved 3

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ISO/TS 24617-5:2014(E)

Figure 1 — Segment structure
A segment might, or might not, be continuous. For instance, ‘either’ plus ‘or’ in ‘Either Tom is lying or
Mary is mistaken’ might be regarded as a discontinuous segment.
Daughters of a segment node in a segment structure may depend on one particular daughter of that
node. Such a daughter is called a ‘governing segment’; the others are called ‘non-governing segments.’ In
this Technical Specification, a segment structure is encoded as a text containing annotations.
NOTE This Technical Specification is neutral between inline annotation and stand-off annotation because
inline annotations are straightforwardly translated to stand-off annotations, as discussed in ISO 24612:2012.
By the conventions introduced here, a governing segment can be annotated by a pair of enclosing curly
braces, and a non-governing segment by a pair of enclosing square brackets. This annotation may be
partial in the sense that there can be segments without such markups.
In the following annotated sentence, for example, ‘{Tom left}’ is a governing segment, ‘[{because} [it was
late]]’ a non-governing segment, ‘{because}’ a governing segment, and ‘[it was late]’ a non-governing
segment. As such annotation is partial, neither ‘Tom’ is enclosed in square brackets, nor is ‘left’ enclosed
in curly braces, for instance.
(1) [{Tom left} [{because} [it was late]].]
Below is an annotated discourse consisting of two sentences.
(2) [[It was late.] {Tom left.}]
Here, the first sentence (a non-governing segment) is regarded as dependent on the second sentence (a
[4]
governing segment), so that the second is the nucleus of this discourse in the RST .
6 Content structure
Without loss of generality, semantic representations have been formulated as labelled directed graphs
in formal semantics, knowledge representation (semantic network in particular)
...

SLOVENSKI STANDARD
SIST-TS ISO/TS 24617-5:2018
01-september-2018
Upravljanje z jezikovnimi viri - Ogrodje za semantično označevanje (SemAF) - 5.
del: Struktura diskurza (SemAF-DS)
Language resource management -- Semantic annotation framework (SemAF) -- Part 5:
Discourse structure (SemAF-DS)
Gestion de ressources langagières -- Cadre d'annotation sémantique (SemAF) -- Partie
5: Structures de discours (SemAF-DS)
Ta slovenski standard je istoveten z: ISO/TS 24617-5:2014
ICS:
01.020 Terminologija (načela in Terminology (principles and
koordinacija) coordination)
35.240.30 Uporabniške rešitve IT v IT applications in information,
informatiki, dokumentiranju in documentation and
založništvu publishing
SIST-TS ISO/TS 24617-5:2018 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST-TS ISO/TS 24617-5:2018

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SIST-TS ISO/TS 24617-5:2018
TECHNICAL ISO/TS
SPECIFICATION 24617-5
First edition
2014-03-01
Language resource management —
Semantic annotation framework
(SemAF) —
Part 5:
Discourse structure (SemAF-DS)
Gestion de ressources langagières — Cadre d’annotation sémantique
(SemAF) —
Partie 5: Structures de discours (SemAF-DS)
Reference number
ISO/TS 24617-5:2014(E)
©
ISO 2014

---------------------- Page: 3 ----------------------
SIST-TS ISO/TS 24617-5:2018
ISO/TS 24617-5:2014(E)

COPYRIGHT PROTECTED DOCUMENT
© ISO 2014
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form
or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior
written permission. Permission can be requested from either ISO at the address below or ISO’s member body in the country of
the requester.
ISO copyright office
Case postale 56 • CH-1211 Geneva 20
Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail copyright@iso.org
Web www.iso.org
Published in Switzerland
ii © ISO 2014 – All rights reserved

---------------------- Page: 4 ----------------------
SIST-TS ISO/TS 24617-5:2018
ISO/TS 24617-5:2014(E)

Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Overview . 2
5 Segment structure . 3
6 Content structure . 4
7 Mapping between segment and content structures . 7
8 Concluding remarks .16
Bibliography .17
© ISO 2014 – All rights reserved iii

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SIST-TS ISO/TS 24617-5:2018
ISO/TS 24617-5:2014(E)

Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www.iso.org/patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation on the meaning of ISO specific terms and expressions related to conformity
assessment, as well as information about ISO’s adherence to the WTO principles in the Technical Barriers
to Trade (TBT) see the following URL: Foreword - Supplementary information
The committee responsible for this document is ISO/TC 37, Terminology and other language and content
resources, Subcommittee SC 04, Language resource management.
ISO 24617 consists of the following parts, under the general title Language resource management —
Semantic annotation framework:
— Part 1: Time and events (SemAF-Time, ISO-TimeML)
— Part 2: Dialogue acts (SemAF-DA)
— Part 4: Semantic roles (SemAF-SR)
— Part 5: Discourse structures (SemAF-DS)
— Part 6: Principles of semantic annotation (SemAF-Basics)
— Part 7: Spatial information (ISO-Space)
— Part 8: Semantic relations in discourse (SemAF-DRel)
iv © ISO 2014 – All rights reserved

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SIST-TS ISO/TS 24617-5:2018
ISO/TS 24617-5:2014(E)

Introduction
Discourse structures play an essential role in the production and analysis of the syntactic, semantic,
and pragmatic features of text, speech, and other types of discourse. This Technical Specification is
a basis both for the annotation, generation and translation (among other processes) of these types of
discourses and of the syntactic, semantic, and pragmatic features derived from them. Note that discourse
structures underlie not only verbal communication (whether spoken, written, or signed) but also non-
verbal discourse (such as a silent video).
The annotation scheme provided here specifies discourse structures that consist of segment structures
and content structures. It also specifies the mappings between these two structures; the mappings are
described by the annotations of discourse segments in texts or some other modalities. In this context,
on the one hand, segment structures are spatiotemporal relations that hold between surface segments
(such as words, phrases, clauses, sentences, and video scenes) and, on the other hand, content structures
are discourse relations that are established between semantic and pragmatic items. Both of these
structures can be represented by means of labelled directed graphs or sometimes simply by trees, as
standardized by LAF (ISO 24612:2012) and SynAF (ISO 24615:2010).
This scheme also provides a common, language-neutral pivot for the interoperation among diverse
formats of discourse structures of various types of document, and can be applied to the generation of
linguistic and non-linguistic expressions. For example, if the discourse structures of speech and other
linguistic data contained in motion pictures are fitted to this scheme, multilingual subtitles for these
pictures can be generated at a reduced cost by means of a standardized tool for multilingual translation.
By the same token, this scheme can facilitate interoperability among various discourse corpora and
collaboration among researchers who use them.
© ISO 2014 – All rights reserved v

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SIST-TS ISO/TS 24617-5:2018

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SIST-TS ISO/TS 24617-5:2018
TECHNICAL SPECIFICATION ISO/TS 24617-5:2014(E)
Language resource management — Semantic annotation
framework (SemAF) —
Part 5:
Discourse structure (SemAF-DS)
1 Scope
A discourse is a process of communication. This Technical Specification addresses how a discourse is
structured in terms of its realization/presentation and content, and shows how its dual structure can
be represented in a graph. The current specification focuses on the annotation of discourse structures
in text only, but it can be extended to discourses in other modalities.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are
indispensable for its application. For dated references, only the edition cited applies. For undated
references, the latest edition of the referenced document (including any amendments) applies.
ISO/IEC 15938-5:2003/Amd.1:2004, Information technology. Multimedia content description interface.
Part 5: Multimedia description schemes AMENDMENT 1: Multimedia description schemes extensions (MPEG-
7 MDS AMD1)
ISO 24612:2012, Language resource management — Linguistic annotation framework (LAF)
ISO 24615:2010, Language resource management — Syntactic annotation framework (SynAF)
ISO 24617-1:2012, Language resource management — Semantic annotation framework — Part 1: Time and
events (SemAF-Time, ISO-TimeML)
ISO 24617-2:2012, Language resource management — Semantic annotation framework — Part 2: Dialogue
acts
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
circumstance
entity which is an event (including dialogue act), state, process, relation, proposition, or set of these
3.2
class
unary predicate, which is a set of entities
3.3
discourse
process of communication, consisting of one or more sentences or sentence fragments
Note 1 to entry: From an abstract viewpoint, data (e.g. words, phrases, sentences, and paragraphs) representing
a communication process is regarded as a discourse. A discourse can be encoded in various media such as text,
hypertext, audio, video, and their possible combinations.
© ISO 2014 – All rights reserved 1

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SIST-TS ISO/TS 24617-5:2018
ISO/TS 24617-5:2014(E)

3.4
discourse relation
semantic/pragmatic relation that holds among two or more circumstances
Note 1 to entry: Some discourse relations, such as example and part, can also hold between objects. In this
document, semantic/pragmatic relations (including discourse relations) are given in italics in the text and with a
gray background in the Figures (e.g. agent, inference, and purpose).
3.5
discourse structure
structure of discourse, comprising segment structure, content structure, and possibly other types of
structure
3.6
entity
semantic/pragmatic entity referenced in discourse, including circumstances, and objects
Note 1 to entry: An entity is represented by a node in a content structure.
3.7
object
semantic entity other than circumstance
Note 1 to entry: Objects include people, buildings, machines, ideas, and rules.
3.8
relational class
class whose instances are circumstances equivalent to relations
3.9
segment
word, phrase, clause, sentence, paragraph, section, chapter, or other partial realization of discourse
Note 1 to entry: A synonym is a ‘discourse segment’. A segment references a semantic and/or pragmatic entity,
which can be a semantic/pragmatic relation. Intrasentential segments are syntactic constituents such as words,
phrases, and clauses. Segments might or might not be continuous: this is discussed in the definition of connectives.
4 Overview
A discourse structure consists of two types of structure: segment structure and content structure. A
segment structure (extending intrasentential syntax) is a data structure that describes how a discourse
has been organized from a formal syntactic perspective. It consists of
a) a set of segments (some partial realizations of discourse), and
b) the syntactic relations holding among them.
A content structure (extending intrasentential semantics) is a data structure that describes from a
logical point of view how a discourse has been organized. It consists of
a) the set of semantic and pragmatic components referred to by the segments of a segment structure
(that is, by some segments of some discourse), and
b) the logical relations established between these semantic representations. These two structures
organize the whole structure of each discourse.
Both types of structure and content structures in particular, can be represented by means of a labelled
directed graph. Various syntactic relations in a segment structure can, for instance, be captured by a
tree (single-rooted graph). Discourse relations in a content structure can also be captured by a more
general graph: The nodes in the graph stand for semantic and pragmatic components and the edges
formalize the relations holding among them. In one way, a segment structure is to a discourse (or part of
2 © ISO 2014 – All rights reserved

---------------------- Page: 10 ----------------------
SIST-TS ISO/TS 24617-5:2018
ISO/TS 24617-5:2014(E)

it) what a syntactic structure is to a sentence (or a sub-sentential component), and a content structure is
to a discourse (or part of it) what a semantic structure is to a sentence (or a sub-sentential component).
[4]
Rhetorical Structure Theory (RST) assumes that discourse has a tree-like structure that can be
regarded as an amalgamation of segment structures and content structures. Corpus annotation based
[2]
on RST considers segment structures involving markables, their annotations and, implicitly, some
sort of content structures derived from them. Other corpus annotation initiatives such as the Prague
[3] [6]
Dependency Treebank and the Penn Discourse TreeBank follow essentially the same approach. By
[1]
contrast Segmented Discourse Representation Theory (SDRT) explicitly discusses content structures
called Segmented Discourse Representation Structures (SDRSs), and with less commitment to segment
structures and the mapping thereof.
By integrating these recent practices in fields such as formal linguistics, knowledge representation and
corpus annotation, this Technical Specification provides an annotation scheme to partially specify the
segment structures and the mapping from them to their corresponding content structures. For the sake
of interoperability across different ISO standards such as LAF and SynAF, this annotation scheme has
been made interoperable with practices concerning syntax and intrasentential semantics; this mapping
from segment structures to content structures is therefore a straightforward extension of the mapping
from syntactic structures to semantic structures, as addressed in many corpora, including the Penn
[7] [5]
TreeBank (PTB) and PropBank .
As for sentences, parse trees describe their syntax, and logical forms represent their semantics. As
for discourses, however, their syntax (i.e. their formal organization) and semantics (i.e. their content
and logical organization) have been discussed in a more intertwined manner. For instance, most of the
literature such as Reference [4] has regarded discourse relations as carrying both semantic and pragmatic
information. This is inconvenient when one wants to focus on the semantic aspects of discourses, for
instance, which can be the case when dealing with hypertexts, games and so on, which lack prefixed
temporal order of presentation, and when discussing multiple (e.g. multilingual) presentations of the
same semantic content.
To distinguish the realization/presentation and the content of a discourse and to address the mapping
between them, this Technical Specification defines segment structures, content structures, and
annotations to segments (discourse units) as part of segment structures. Segment structures represent
the way in which the discourse is arranged, and consist of segments (e.g. words, phrases, clauses,
sentences, paragraphs, sections, and chapters) together with the syntagmatic organization relations
holding among them. Content structures represent the semantic and pragmatic content of discourses,
and consist of nodes and links that represent entities referenced by segments. The main goal of this
Technical Specification is to define an annotation scheme that concisely addresses segment structures,
content structures and mappings between them. In other words, each segment annotated according
to this scheme should represent a set of correspondences between segment structures and content
structures.
A major basis of this Technical Specification is ISO/IEC 15938-5:2003/Amd.1:2004. This Technical
Specification is mostly restricted to discourse structures, although the Linguistic DS also deals with
predicate-argument structures and dialogue acts.
This Technical Specification addresses both the intrasentential and intersentential aspects of segment
structures. The annotation of intrasentential aspects is compliant with ISO 24615:2010; that of both the
aspects is consistent with the other two published parts ISO 24617-1:2012 and ISO 24617-2:2012. Their
annotations and representations can be encoded according to ISO 24612:2012 as it supports labelled
directed graphs.
5 Segment structure
A segment structure of a discourse addresses its syntactic organizations. This Technical Specification
assumes that, not all, but some segment structures are represented as trees with their nodes representing
discourse segments. If segment S (as a sequential data such as text and speech) has directed descendants
(called ‘daughters’), S is their concatenation. For instance, Figure 1 represents the segment structure of
a discourse ‘Tom left. It was late.’ which consists of two daughters ‘It was late.’ and ‘Tom left.’
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Figure 1 — Segment structure
A segment might, or might not, be continuous. For instance, ‘either’ plus ‘or’ in ‘Either Tom is lying or
Mary is mistaken’ might be regarded as a discontinuous segment.
Daughters of a segment node in a segment structure may depend on one particular daughter of that
node. Such a daughter is called a ‘governing segment’; the others are called ‘non-governing segments.’ In
this Technical Specification, a segment structure is encoded as a text containing annotations.
NOTE This Technical Specification is neutral between inline annotation and stand-off annotation because
inline annotations are straightforwardly translated to stand-off annotations, as discussed in ISO 24612:2012.
By the conventions introduced here, a governing segment can be annotated by a pair of enclosing curly
braces, and a non-governing segment by a pair of enclosing square brackets. This annotation may be
partial in the sense that there can be segments without such markups.
In the following annotated sentence, for example, ‘{Tom left}’ is a governing segment, ‘[{because} [it was
late]]’ a non-governing segment, ‘{because}’ a governing segment, and ‘[it was late]’ a non-governing
segment. As such annotation is partial, neither ‘Tom’ is enclosed in square brackets, nor is ‘left’ enclosed
...

SLOVENSKI STANDARD
SIST-TS ISO/TS 24617-5:2018
01-september-2018
8SUDYOMDQMH]MH]LNRYQLPLYLUL2JURGMH]DVHPDQWLþQRR]QDþHYDQMH6HP$)
GHO6WUXNWXUDGLVNXU]D6HP$)'6
Language resource management -- Semantic annotation framework (SemAF) -- Part 5:
Discourse structure (SemAF-DS)
Gestion de ressources langagières -- Cadre d'annotation sémantique (SemAF) -- Partie
5: Structures de discours (SemAF-DS)
Ta slovenski standard je istoveten z: ISO/TS 24617-5:2014
ICS:
01.020 7HUPLQRORJLMDQDþHODLQ Terminology (principles and
NRRUGLQDFLMD coordination)
35.060 Jeziki, ki se uporabljajo v Languages used in
informacijski tehniki in information technology
tehnologiji
SIST-TS ISO/TS 24617-5:2018 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST-TS ISO/TS 24617-5:2018
TECHNICAL ISO/TS
SPECIFICATION 24617-5
First edition
2014-03-01
Language resource management —
Semantic annotation framework
(SemAF) —
Part 5:
Discourse structure (SemAF-DS)
Gestion de ressources langagières — Cadre d’annotation sémantique
(SemAF) —
Partie 5: Structures de discours (SemAF-DS)
Reference number
ISO/TS 24617-5:2014(E)
©
ISO 2014

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ISO/TS 24617-5:2014(E)

COPYRIGHT PROTECTED DOCUMENT
© ISO 2014
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form
or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior
written permission. Permission can be requested from either ISO at the address below or ISO’s member body in the country of
the requester.
ISO copyright office
Case postale 56 • CH-1211 Geneva 20
Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail copyright@iso.org
Web www.iso.org
Published in Switzerland
ii © ISO 2014 – All rights reserved

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Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Overview . 2
5 Segment structure . 3
6 Content structure . 4
7 Mapping between segment and content structures . 7
8 Concluding remarks .16
Bibliography .17
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Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www.iso.org/patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation on the meaning of ISO specific terms and expressions related to conformity
assessment, as well as information about ISO’s adherence to the WTO principles in the Technical Barriers
to Trade (TBT) see the following URL: Foreword - Supplementary information
The committee responsible for this document is ISO/TC 37, Terminology and other language and content
resources, Subcommittee SC 04, Language resource management.
ISO 24617 consists of the following parts, under the general title Language resource management —
Semantic annotation framework:
— Part 1: Time and events (SemAF-Time, ISO-TimeML)
— Part 2: Dialogue acts (SemAF-DA)
— Part 4: Semantic roles (SemAF-SR)
— Part 5: Discourse structures (SemAF-DS)
— Part 6: Principles of semantic annotation (SemAF-Basics)
— Part 7: Spatial information (ISO-Space)
— Part 8: Semantic relations in discourse (SemAF-DRel)
iv © ISO 2014 – All rights reserved

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Introduction
Discourse structures play an essential role in the production and analysis of the syntactic, semantic,
and pragmatic features of text, speech, and other types of discourse. This Technical Specification is
a basis both for the annotation, generation and translation (among other processes) of these types of
discourses and of the syntactic, semantic, and pragmatic features derived from them. Note that discourse
structures underlie not only verbal communication (whether spoken, written, or signed) but also non-
verbal discourse (such as a silent video).
The annotation scheme provided here specifies discourse structures that consist of segment structures
and content structures. It also specifies the mappings between these two structures; the mappings are
described by the annotations of discourse segments in texts or some other modalities. In this context,
on the one hand, segment structures are spatiotemporal relations that hold between surface segments
(such as words, phrases, clauses, sentences, and video scenes) and, on the other hand, content structures
are discourse relations that are established between semantic and pragmatic items. Both of these
structures can be represented by means of labelled directed graphs or sometimes simply by trees, as
standardized by LAF (ISO 24612:2012) and SynAF (ISO 24615:2010).
This scheme also provides a common, language-neutral pivot for the interoperation among diverse
formats of discourse structures of various types of document, and can be applied to the generation of
linguistic and non-linguistic expressions. For example, if the discourse structures of speech and other
linguistic data contained in motion pictures are fitted to this scheme, multilingual subtitles for these
pictures can be generated at a reduced cost by means of a standardized tool for multilingual translation.
By the same token, this scheme can facilitate interoperability among various discourse corpora and
collaboration among researchers who use them.
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SIST-TS ISO/TS 24617-5:2018
TECHNICAL SPECIFICATION ISO/TS 24617-5:2014(E)
Language resource management — Semantic annotation
framework (SemAF) —
Part 5:
Discourse structure (SemAF-DS)
1 Scope
A discourse is a process of communication. This Technical Specification addresses how a discourse is
structured in terms of its realization/presentation and content, and shows how its dual structure can
be represented in a graph. The current specification focuses on the annotation of discourse structures
in text only, but it can be extended to discourses in other modalities.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are
indispensable for its application. For dated references, only the edition cited applies. For undated
references, the latest edition of the referenced document (including any amendments) applies.
ISO/IEC 15938-5:2003/Amd.1:2004, Information technology. Multimedia content description interface.
Part 5: Multimedia description schemes AMENDMENT 1: Multimedia description schemes extensions (MPEG-
7 MDS AMD1)
ISO 24612:2012, Language resource management — Linguistic annotation framework (LAF)
ISO 24615:2010, Language resource management — Syntactic annotation framework (SynAF)
ISO 24617-1:2012, Language resource management — Semantic annotation framework — Part 1: Time and
events (SemAF-Time, ISO-TimeML)
ISO 24617-2:2012, Language resource management — Semantic annotation framework — Part 2: Dialogue
acts
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
circumstance
entity which is an event (including dialogue act), state, process, relation, proposition, or set of these
3.2
class
unary predicate, which is a set of entities
3.3
discourse
process of communication, consisting of one or more sentences or sentence fragments
Note 1 to entry: From an abstract viewpoint, data (e.g. words, phrases, sentences, and paragraphs) representing
a communication process is regarded as a discourse. A discourse can be encoded in various media such as text,
hypertext, audio, video, and their possible combinations.
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3.4
discourse relation
semantic/pragmatic relation that holds among two or more circumstances
Note 1 to entry: Some discourse relations, such as example and part, can also hold between objects. In this
document, semantic/pragmatic relations (including discourse relations) are given in italics in the text and with a
gray background in the Figures (e.g. agent, inference, and purpose).
3.5
discourse structure
structure of discourse, comprising segment structure, content structure, and possibly other types of
structure
3.6
entity
semantic/pragmatic entity referenced in discourse, including circumstances, and objects
Note 1 to entry: An entity is represented by a node in a content structure.
3.7
object
semantic entity other than circumstance
Note 1 to entry: Objects include people, buildings, machines, ideas, and rules.
3.8
relational class
class whose instances are circumstances equivalent to relations
3.9
segment
word, phrase, clause, sentence, paragraph, section, chapter, or other partial realization of discourse
Note 1 to entry: A synonym is a ‘discourse segment’. A segment references a semantic and/or pragmatic entity,
which can be a semantic/pragmatic relation. Intrasentential segments are syntactic constituents such as words,
phrases, and clauses. Segments might or might not be continuous: this is discussed in the definition of connectives.
4 Overview
A discourse structure consists of two types of structure: segment structure and content structure. A
segment structure (extending intrasentential syntax) is a data structure that describes how a discourse
has been organized from a formal syntactic perspective. It consists of
a) a set of segments (some partial realizations of discourse), and
b) the syntactic relations holding among them.
A content structure (extending intrasentential semantics) is a data structure that describes from a
logical point of view how a discourse has been organized. It consists of
a) the set of semantic and pragmatic components referred to by the segments of a segment structure
(that is, by some segments of some discourse), and
b) the logical relations established between these semantic representations. These two structures
organize the whole structure of each discourse.
Both types of structure and content structures in particular, can be represented by means of a labelled
directed graph. Various syntactic relations in a segment structure can, for instance, be captured by a
tree (single-rooted graph). Discourse relations in a content structure can also be captured by a more
general graph: The nodes in the graph stand for semantic and pragmatic components and the edges
formalize the relations holding among them. In one way, a segment structure is to a discourse (or part of
2 © ISO 2014 – All rights reserved

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it) what a syntactic structure is to a sentence (or a sub-sentential component), and a content structure is
to a discourse (or part of it) what a semantic structure is to a sentence (or a sub-sentential component).
[4]
Rhetorical Structure Theory (RST) assumes that discourse has a tree-like structure that can be
regarded as an amalgamation of segment structures and content structures. Corpus annotation based
[2]
on RST considers segment structures involving markables, their annotations and, implicitly, some
sort of content structures derived from them. Other corpus annotation initiatives such as the Prague
[3] [6]
Dependency Treebank and the Penn Discourse TreeBank follow essentially the same approach. By
[1]
contrast Segmented Discourse Representation Theory (SDRT) explicitly discusses content structures
called Segmented Discourse Representation Structures (SDRSs), and with less commitment to segment
structures and the mapping thereof.
By integrating these recent practices in fields such as formal linguistics, knowledge representation and
corpus annotation, this Technical Specification provides an annotation scheme to partially specify the
segment structures and the mapping from them to their corresponding content structures. For the sake
of interoperability across different ISO standards such as LAF and SynAF, this annotation scheme has
been made interoperable with practices concerning syntax and intrasentential semantics; this mapping
from segment structures to content structures is therefore a straightforward extension of the mapping
from syntactic structures to semantic structures, as addressed in many corpora, including the Penn
[7] [5]
TreeBank (PTB) and PropBank .
As for sentences, parse trees describe their syntax, and logical forms represent their semantics. As
for discourses, however, their syntax (i.e. their formal organization) and semantics (i.e. their content
and logical organization) have been discussed in a more intertwined manner. For instance, most of the
literature such as Reference [4] has regarded discourse relations as carrying both semantic and pragmatic
information. This is inconvenient when one wants to focus on the semantic aspects of discourses, for
instance, which can be the case when dealing with hypertexts, games and so on, which lack prefixed
temporal order of presentation, and when discussing multiple (e.g. multilingual) presentations of the
same semantic content.
To distinguish the realization/presentation and the content of a discourse and to address the mapping
between them, this Technical Specification defines segment structures, content structures, and
annotations to segments (discourse units) as part of segment structures. Segment structures represent
the way in which the discourse is arranged, and consist of segments (e.g. words, phrases, clauses,
sentences, paragraphs, sections, and chapters) together with the syntagmatic organization relations
holding among them. Content structures represent the semantic and pragmatic content of discourses,
and consist of nodes and links that represent entities referenced by segments. The main goal of this
Technical Specification is to define an annotation scheme that concisely addresses segment structures,
content structures and mappings between them. In other words, each segment annotated according
to this scheme should represent a set of correspondences between segment structures and content
structures.
A major basis of this Technical Specification is ISO/IEC 15938-5:2003/Amd.1:2004. This Technical
Specification is mostly restricted to discourse structures, although the Linguistic DS also deals with
predicate-argument structures and dialogue acts.
This Technical Specification addresses both the intrasentential and intersentential aspects of segment
structures. The annotation of intrasentential aspects is compliant with ISO 24615:2010; that of both the
aspects is consistent with the other two published parts ISO 24617-1:2012 and ISO 24617-2:2012. Their
annotations and representations can be encoded according to ISO 24612:2012 as it supports labelled
directed graphs.
5 Segment structure
A segment structure of a discourse addresses its syntactic organizations. This Technical Specification
assumes that, not all, but some segment structures are represented as trees with their nodes representing
discourse segments. If segment S (as a sequential data such as text and speech) has directed descendants
(called ‘daughters’), S is their concatenation. For instance, Figure 1 represents the segment structure of
a discourse ‘Tom left. It was late.’ which consists of two daughters ‘It was late.’ and ‘Tom left.’
© ISO 2014 – All rights reserved 3

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Figure 1 — Segment structure
A segment might, or might not, be continuous. For instance, ‘either’ plus ‘or’ in ‘Either Tom is lying or
Mary is mistaken’ might be regarded as a discontinuous segment.
Daughters of a segment node in a segment structure may depend on one particular daughter of that
node. Such a daughter is called a ‘governing segment’; the others are called ‘non-governing segments.’ In
this Technical Specification, a segment structure is encoded as a text containing annotations.
NOTE This Technical Specification is neutral between inline annotation and stand-off annotation because
inline annotations are straightforwardly translated to stand-off annotations, as discussed in ISO 24612:2012.
By the conventions introduced here, a governing segment can be annotated by a pair of enclosing curly
braces, and a non-governing segment by a pair of enclosing square brackets. This annotation may be
partial in the sense that there can be segments without such markups.
In the following annotated sentence, for example, ‘{Tom left}’ is a governing segment, ‘[{because} [it was
late]]’ a non-governing segment, ‘{because}’ a governing segment, and ‘[it was late]’ a non-governing
segment. As such annotation is partial, neither ‘Tom’ is enclosed in square brackets, nor is ‘left’ enclosed
in curly braces,
...