ISA-17 17th Joint ACL - ISO Workshop on Interoperable Semantic Annotation Workshop Proceedings
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ISA-17 17th Joint ACL - ISO Workshop on Interoperable Semantic Annotation Workshop Proceedings Harry Bunt, editor June 16 - 17, 2021
©2021 The Association for Computational Linguistics Order copies of this and other ACL proceedings from: Association for Computational Linguistics (ACL) 209 N. Eighth Street Stroudsburg, PA 18360 USA Tel: +1-570-476-8006 Fax: +1-570-476-0860 acl@aclweb.org ISBN 978-1-954085-20-6 ii
Message from the General Chair Welcome the proceedings of the online ISA workshop at IWCS 2021! Last year, the ISA-16 workshop at LREC 2020 had to be canceled altogether, but following the decision of the LREC organisers we did publish the accepted submissions to the workshop in the proceedings that can be found online at the ISA-16 website and in the ACL anthology. This year we are in a slightly better shape since the IWCS 2021 conference that hosts the ISA-17 workshop was planned from the beginning to be held in online form. While online presentation of papers and discussion tend to suffer from the online format, this does feel like a step forward compared to last year. In particular, in 2020 we had planned to organise two exciting shared tasks, one on the annotation of quantification phenomena and one on the representation of visual information, which were postponed to this year and will go ahead this time. The discussion notes and annotations that were submitted for these shared tasks have not been included in these proceedings, but are available at the ISA-17 website (https://sigsem.uvt.nl/isa17). We thank the members of the ISA-17 program committee for reviewing the submitted papers timely and thoroughly, and we thank the authors of accepted papers for revising their contributions according to the original time schedule, taking the review comments into account. We thank the participants in the two shared tasks for their contributions, which promise to be most valuable for the further development of adequate semantic annotation and representation schemes. Thank you! Harry Bunt iii
Organizing Committee Harry Bunt, Tilburg University (Netherlands) Nancy Ide, Vassar College, Poughkeepsie, NY (USA) Kiyong Lee, Korea University, Seoul (South Korea) Volha Petukhova, Saarland University, Saarbrücken (Germany) James Pustejovsky, Brandeis University, Waltham, MA (USA) Laurent Romary, INRIA/Humboldt University, Berlin (Germany) Ielka van der Sluis, University of Groningen (Netherlands) Program Committee Jan Alexandersson Johan Bos Harry Bunt Nicoletta Calzolari Jae-Woong Choe Robin Cooper Ludivine Crible David DeVault Simon Dobnik Jens Edlund Alex Fang Robert Gaizauskas Koiti Hasida Nancy Ide Elisabetta Jezek Nikhil Krishnaswamy Kiyong Lee Paul McKevitt Adam Meyers Philippe Muller Rainer Osswald Volha Petukhova Massimo Poesio Andrei Popescu-Belis Laurent Preévot James Pustejovsky Livio Robaldo Laurent Romary Ielka van der Sluis Manfred Stede Matthew Stone Thorsten Trippel Carl Vogel Menno van Zaanen Annie Zaanen Heike Zinsmeister v
Table of Contents Developing a multilayer semantic annotation scheme based on ISO standards for the visualization of a newswire corpus Purificação Silvano, António Leal, Fátima Silva, Inês Cantante, Fatima Oliveira and Alípio Mario Jorge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 Towards the ISO 24617-2-compliant Typology of Metacognitive Events Volha Petukhova and Hafiza Erum Manzoor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 Annotating Quantified Phenomena in Complex Sentence Structures Using the Example of Generalising Statements in Literary Texts Tillmann Dönicke, Luisa Gödeke and Hanna Varachkina . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 The ISA-17 Quantification Challenge: Background and introduction Harry Bunt . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 Discourse-based Argument Segmentation and Annotation Ekaterina Saveleva, Volha Petukhova, Marius Mosbach and Dietrich Klakow . . . . . . . . . . . . . . . . . 41 Converting Multilayer Glosses into Semantic and Pragmatic forms with GENLIS Rodolfo Delmonte, Serena Trolvi and Francesco Stiffoni . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54 Unleashing annotations with TextAnnotator: Multimedia, multi-perspective document views for ubiqui- tous annotation Giuseppe Abrami, Alexander Henlein, Andy Lücking, Attila Kett, Pascal Adeberg and Alexander Mehler . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65 vii
Workshop Program Developing a multilayer semantic annotation scheme based on ISO standards for the visualization of a newswire corpus Purificação Silvano, António Leal, Fátima Silva, Inês Cantante, Fatima Oliveira and Alípio Mario Jorge Towards the ISO 24617-2-compliant Typology of Metacognitive Events Volha Petukhova and Hafiza Erum Manzoor Annotating Quantified Phenomena in Complex Sentence Structures Using the Ex- ample of Generalising Statements in Literary Texts Tillmann Dönicke, Luisa Gödeke and Hanna Varachkina The ISA-17 Quantification Challenge: Background and introduction Harry Bunt Discourse-based Argument Segmentation and Annotation Ekaterina Saveleva, Volha Petukhova, Marius Mosbach and Dietrich Klakow Converting Multilayer Glosses into Semantic and Pragmatic forms with GENLIS Rodolfo Delmonte, Serena Trolvi and Francesco Stiffoni Unleashing annotations with TextAnnotator: Multimedia, multi-perspective docu- ment views for ubiquitous annotation Giuseppe Abrami, Alexander Henlein, Andy Lücking, Attila Kett, Pascal Adeberg and Alexander Mehler ix
Developing a multilayer semantic annotation scheme based on ISO standards for the visualization of a newswire corpus Purificação Silvano1, António Leal2, Fátima Silva3, Inês Cantante4, Fátima Oliveira5 & Alípio Mário Jorge6 1,2,3,4,5 University of Porto/ Centre of Linguistics 6University of Porto/ INESC 1 msilvano@letras.up.pt, 2jleal@letras.up.pt,3mhenri@letras.up.pt, 4 cantante.ines@gmail.com, 5moliv@letras.up.pt, 6amjorge@fc.up.pt Abstract disadvantages of adapting/ adopting an existing model, or of creating one. Ideally, the model is In this paper, we describe the process of custom designed to deal with all the specificities developing a multilayer semantic of a particular project, but also broad enough so annotation scheme designed for extracting that it can be applied to other datasets. In fact, with information from a European Portuguese corpus of news articles, at three levels, the growth of the Semantic Web and Linguistic temporal, referential and semantic role Linked Data (Chiarcos et al., 2020), labelling. The novelty of this scheme is the interoperability is key to read and to interpret harmonization of parts 1, 4 and 9 of the ISO linguistic resources (Ide and Pustejovsky, 2010). 24617 Language resource management - With all the above-mentioned provisos in mind, Semantic annotation framework. This we developed a multilayer semantic annotation annotation framework includes a set of scheme by combining three standards from the entity structures (participants, events, Language resource management-Semantic times) and a set of links (temporal, annotation framework: Part 1- Time and events aspectual, subordination, objectal and (ISO-24617-1), Part 4- Semantic roles (ISO- semantic roles) with several tags and attribute values that ensure adequate 24617-4) and Part 9- Referential annotation semantic and visual representations of news framework (ISO-24617-9). In addition to stories. promoting interoperability, our model has proven to be able to markup manually the relevant features 1 Introduction of the genre news to generate visual representations of their narratives. Moreover, our The development of an annotation framework can proposal operationalizes the integration of three be an overwhelming task, even more when its different standards in the same framework, which purpose is to account for different linguistic is, to the best of our knowledge, a novelty. phenomena. However, as challenging as it may be, This multilayer semantic annotation scheme designing an annotation scheme is an was designed to annotate a European Portuguese indispensable step to generate language resources corpus of news articles in three different, but that can be the starting point of fundamental complementary, levels, temporal, referential and corpus-based linguistic research. thematic, within the Text2Story project 1 , which When deciding on an annotation framework, aims to extract narratives from news, represent one has to take into consideration several factors them in intermediate data structures, and make (Pustejovsky et al., 2017), such as main objectives these available to subsequent media production of the annotation, the linguistic phenomena under processes, i.e., visualizations such as message analysis, the corpus genre, and the nature of the sequence charts (MSC) and knowledge graphs annotation, and weigh in the advantages and (KG). In this paper, we document the decision- 1 https://text2story.inesctec.pt/ 1 Proceedings of the 17th Joint ACL - ISO Workshop on Interoperable Semantic Annotation, pages 1–13 June 16–17, 2021. ©2021 Association for Computational Linguistics
making process about which annotation format to the case of news articles, this requires featuring adopt, what adjustments to make, and how to participants, events and times, as well the harmonize the three layers into an integrated and relationships between them. For these reasons, the wide-ranging model. annotation scheme that we designed encompasses three intertwined semantic layers: temporal, 2 Background and Motivation referential and thematic. Since our aim was to adopt a coherent and interoperable annotation News may frequently assume the format of a story scheme with these three layers, and because none that reports on current events involving one or of the existing proposals satisfied these requisites, more entities in given time and place. In addition to we designed an annotation scheme which the main event, however, news stories typically compatibilizes three ISO. present contextual content that allows connecting it to others, explaining the circumstances and 3 Related work consequences of its occurrence. It may also include other complementary information that frames, Over the last years, there has been a proliferation of comments, clarifies, or evaluates the reported multilayer corpora, that is, corpora that “contain events (Caswell and Dörr, 2019; Choubey et al., mutually independent forms of information, which 2020; cf. also van Dijk, 1985; Bell, 1991). A cannot be derived from one another reliably” complete story usually answers six questions: (Zeldes, 2019: 4). These layers can be defined in an what, who, where, when, why, and how, that is, independent way and they “are explicitly analyzed 5W1H (a.o. Bonet-Jover et al., 2021), following a using multiple, independent annotation schemes” top-down organization, corresponding to an (Zeldes, 2019: 7), or resorting to one unique inverted pyramid discourse structure (cf. Rabe scheme that integrates all the layers. In fact, an in- 2008), in which information flows in decreasing depth analysis of the relevant literature reveals that order of importance. A news organization structure there are many different types of multilayer usually features a title, a lead, and the body. In annotation schemes. In the remainder of this many cases, the lead or introductory paragraph section, we will only present a brief overview of condenses the answers to the above six questions some of those proposals. and is followed by complementary information One of the most well accomplished and far- (a.o. Thomson et al., 2008; Norambuena et al., reaching multilayer annotation schemes is the one 2020). Sometimes, the answer to some of the developed within the Groningen Meaning Bank questions is distributed throughout the text (Bonet- (GMB) (Basile et al., 2012; Bos et al., 2017). Jover et al., 2021). Because of this organization, Besides morphological and syntactic annotation, it events frequently follow a non-chronological comprises different semantic annotation levels, order, presenting a complex time structure such as named entity recognition, temporal regarding other kinds of narratives (Zahid et al., features, and thematic roles. The adopted semantic 2019). Besides, the narrative may return to formalism is an extension of Discourse previous data, as well as adding information (a.o. Representation Theory (Kamp and Reyle, 1993), van Dijk, 1985; Thomson et al., 2008; Choubey et which renders a semantic representation (discourse al., 2020). representation structures) that unifies the various Establishing the temporal sequencing of events, layers. Another important feature of this scheme is their participants, and interrelations is crucial to that it was designed to analyze linguistic understand the news story, and ultimately to extract phenomena in texts, instead of only sentences, and the narratives to be represented graphically by it has been used quite successfully in 10,000 texts means of MSC (Harel and Thiagarajan, 2003) or from different genres, namely news and fables. Its KG (Ehrlinger and Wöß, 2016), which is our implementation requires a human-aided machine project’s main objective. These visualizations by annotation insofar as it employs NLP software such portraying the narratives more schematically can as an automatic tagger for named entity be of great interest to news agencies, for example. recognition, VerbNet (Schuler, 2005) for semantic The more overarching and rigorous the annotation role labelling, a semantic analyzer for coreference, the more informative is the visualization, and, in and then a module Boxer (Bos, 2005, 2008; Curran 2
et al. 2007), responsible for the overall semantic of annotating semantically data at a sentential and analysis, but also relies on the input of experts and textual level. This task requires not only a great general public. Although, in terms of semantic amount of time, but also a wide variety and annotation, it is one of the most complete, this substantial number of resources. Nonetheless, scheme lacks information about more referential semantic schemes to represent the meaning of texts relations. Moreover, since the temporal annotation are of utmost relevance to the development of is based on DRT-language, it does not integrate tags different applications. about lexical and contextual meaning with bearing on temporal interpretation, namely a more 4 The Annotation scheme diversified class of events, and other link types between events. 4.1 The process Other multilayer annotation schemes have been Building a bootstrapping annotation scheme is a developed for Manually Annotated Sub-Corpus very complex and time-consuming endeavor (MASC) (Ide et al., 2008), Georgetown University involving different phases. After the literature Multilayer Corpus (GUM) (Zeldes and Simonson, review, we started by defining the tags and their 2016; Zeldes, 2017), OntoNotes (Hovy et al., attributes first for the temporal layer, then for the 2006), for AMALGUM (Gessler et al., 2020), or referential level, and finally for the semantic role SenSem (Fernández and Vázquez, 2014), just to labelling. To create a model, we followed the name a few, but none of those provide a MATTER (Pustejovsky and Stubs, 2012) sub- comprehensive and harmonized semantic cycle, MAMA, with four steps, (1) model, (2) framework suitable to handle the linguistic annotate, (3) evaluate and (4) revise. This process phenomena that we need to address. allowed us to identify and resolve the scheme’s For European Portuguese (EP), one can point inconsistencies, gaps and incompatibilities, and to out the scheme used in CINTIL DeepBank (Branco gradually improve it so that it could properly et al., 2010), which is a corpus of Portuguese news account for the linguistic data, and to deliver the and novels that is annotated with several necessary input for the visualization task. This grammatical information (morphological, cycle was repeated several times until we were syntactic, and semantic) for each satisfied with the model. The annotation tool that sentence. Currently, there are 32497 sentences, we used, BRAT (brat rapid annotation tool) mainly from news, which were semi-automatically (Stenetorp et al., 2012), enabled the updates of the annotated with Treebank, DependencyBank, annotation scheme without having to rebuild the Propbank, and LogicalFormBank (with formal whole scheme. representations of the sentences meanings using Minimal Recursion Semantics). However, the 4.1.1 Temporal Layer CINTIL DeepBank’s scheme does not include a Temporal interpretation plays a crucial part in level for referential annotation, nor for temporal understanding how the events are organized in annotation. The fact that only the sentences that the natural language texts. For this reason, extraction grammar can parse are included in the corpus is a of temporal information has been receiving a lot of downside. Additionally, though each level of attention within NLP during the past few years. annotation can be accessed separately, a unifying One approach to extract temporal features, and formalism that combines all the layers is missing. eventually to rebuild chronological sequences of Regarding schemes aimed exclusively at events, is designing a suitable annotation scheme. semantic annotation, some are intended to handle a In this field, research has started with the extraction specific phenomenon, resort to non-standardized of time expressions in message understanding markup language, and are not widely known (cf. conferences (MUCs) and progressed to relating for an overview (Gries and Berez, 2017). events to times (eg. Filatova and Hovy, 2001; Katz Moreover, the majority deals with lexical and Arosio, 2001; Song et al., 2016). From the problems, such as word disambiguation, and less growing investment on temporal extraction, on the with compositional semantics. The scarcity of one hand, and from its usefulness, on the other proposals within this branch of semantics can be hand, ensued not only a significant number of explained by the complexity underlying the process corpora annotated according to different schemes, 3
but also annotation standards. One of these Regarding the tag times, we adopted a very standards is TimeML (Pustejovsky et al., 2003a, simple scheme, which meets the needs of our 2003b), based on the work of Setzer (2001), Setzer project. The attributes that incorporate our & Gaizauskas (2000a, 2000b, 2001) and Ferro et annotation scheme are the required ones, according al. (2003), from which ISO-TimeML (ISO 24617- to ISO-24617-1, that is, type (date, time, duration 1) stemmed. and set) and value (the specific value of the type). ISO-TimeML, a model grounded on linguistic We have also integrated two optional attributes: approaches (eg. Reichenbach, 1947; Comrie, temporal function with the value publication time 1985), defines a full-fledged markup language that and anchor time, which are pertinent to process permits a fine-grained annotation of time time expressions common in news articles, like expressions, events, and temporal relations hoje ‘today’, na sexta-feira ‘Friday’. between events and between events and time The sequencing of the events, that is, their expressions. Its efficacy and productivity in ordering, is essential to depict the way the narrative capturing the text’s temporal structure is evidenced evolves in time. ISO-24617-1 specifies the by corpora such as TIDES Temporal Corpus adequate manner to establish the events timeline, (Gerber et al., 2002), TimeBank (Pustejovsky et al., as well as the relations between events and time 2003b), composed of news articles, or Sun et al. expressions by postulating TLinks, which we (2013)’s corpus with clinical narratives. Costa integrated in our scheme. In turn, the ALink, by (2012) and Costa and Branco (2010, 2012) use specifying the relation between aspectual verbs and TimeML to annotate for the first time a EP corpus their event arguments, gives crucial input to create with temporal information, TimeBankPT. This the visualizations of the events. The relevance of corpus, nonetheless, only comprises the the SLink derives from the fact that the news translations of texts from the original TimeBank, as articles frequently include contexts of well as the same annotations with some adaptations subordinating relationships between events. We required by language specificities. omitted the measuring link (MLink) because the Compared to the scheme employed by information it conveys is already captured to a TimeBankPT, the temporal tagset and linkset that certain extent by the value duration for the attribute we subscribe follow more closely ISO-24617-1. As type of tag times. The values for the three links of expected, bearing in mind the project’s main aim, our model are the ones proposed by ISO-24617-1. that is, visualization of news narratives, and the necessity of not overloading the scheme with 4.1.2 Referential Layer unnecessary information, some tags and links were Pointing out to the referring expressions in a text, excluded. Thus, for the temporal layer, our scheme identifying the discourse entities denoted by those incorporates two tags, event and times, and three expressions, and establishing the links between links, temporal link (TLink), aspectual link them are key tasks to reference annotation, and (ALink) and subordination link (SLink). underly referential phenomena in discourse, such The tag event marks eventualities (Bach, 1985), as anaphora. represented by tensed or untensed verbs, In our corpus, those referring expressions nominalizations, adjectives, predicative correspond to named entities, or participants that constructions or prepositional complements. The play an important role in the story. Therefore, we combination of all the required attributes, class, needed a framework to deal with named entities part of speech, tense, aspect, verb form, mood, recognition and their relation throughout the news modality and polarity, provides the necessary texts. ISO-24617-9 met these needs, as it is a meta- information about temporal, aspectual and modal model of referential annotation that articulates the features of events. With respect to the values for discourse domain with the linguistic domain, each attribute, we maintained the ones established contributing to a comprehensive representation of by ISO-24617-1, namely for Italian, but added in the discourse entities, the referring expressions that the attribute mood the value future to account for denote them, and their relations. its modal uses, and the modality values dever Despite following the standard in its overall (‘must’), poder (‘can’), ter de (‘have to’) and ser guidelines, we did not annotate all its categories, capaz de (‘be able to’). and both discourse entity structures and referential 4
expression structures were kept as simple as nominal anaphora’s mechanisms. Unlike many possible, to avoid overloading the process of studies that focus on anaphora resolution and annotation: the former include only information depict only coreferential mechanisms, leaving out concerning the lexical head (noun, pronoun), other types of relations, the adopted framework whereas the latter include information concerning allows for the marking of different types of domain (individuation and types) and involvement. anaphoric linkage between entities, namely direct The individuation attribute, with the values set, and indirect anaphora.2 individual and mass, follows ISO-24617-9 definitions, while for involvement we defined the 4.1.3 Semantic Role Layer values: 0 (the empty set); 1 (a set with only one The task of semantic role labelling for English texts entity); >1 (a set with more than one entity, but less usually uses one of the following frameworks (see than the totality of entities in the domain); all (the also ISO 24617-4, Annex B): FrameNet (Baker et totality of entities in the domain = universal al., 1998), VerbNet (Schuler, 2005), PropBank quantification); undef (undefined involvement). (Palmer et al., 2005), EngVallex (Cinková, 2006), As for types, since ISO 24617-9 does not and LIRICS (Petukhova and Bunt, 2008). provide a typology of named entities, we selected, As for EP data, there are some proposals that considering our corpus text genre and the purpose approach the issue of semantic role labelling, of the project, a tagset of six named entities: PER, typically using the methodology of PropBank and ORG, LOC, OBJ, NAT, OTHER. In fact, the VerbNet. However, these proposals have a very definition of named entities is neither easy nor narrow scope, working with small datasets and consensual, and there are several typologies for small lists of (typically) verbs. Some examples of their classification, being the number and types of these works are PropBankPT (Branco et al., 2012), entities influenced by factors, such as the domain a corpus of 3406 sentences translated from the Wall from which they are extracted or the purpose of its Street Journal, and annotated with information classification (for a survey on this topic, see, a.o. concerning constituency structure (phrase Nouvel et al., 2016; Goyal et al., 2018). This tagset constituency and grammatical relations) and is an adaptation of general categories depicted in semantic roles; and CINTIL-PropBank (Branco et the named entity classification typologies used in al., 2012), a corpus of 10039 sentences extracted many other corpora, including multilayer ones. The from news and novels, and annotated with first three named entities are common to all the information concerning constituency structure and annotated corpora while the others may vary. semantic roles. There is also ViPer (Talhadas et al., In what concerns the relations included in ISO- 2013), a verbal lexical database with information 24617-9, we did not include in our specifications about the verb’s arguments semantic roles (using the lexical relational links between entity structures PropBank approach) manually annotated. and referring expressions (eg. synonym, antonym, However, there are some aspects of the semantic hyponym, meronym), the referential status of roles list that is used that can be problematic for our referring expressions (old/new), and the properties project (for instance, event-denoting nouns are of discourse entities (abstractness, animacy, treated as arguments of the “occurrence” type, alienability, natural gender and cardinality), instead of being treated as events, like in ISO- because they were not necessary for the visual 24617-1). representations of news. As a matter of fact, it is So, the semantic role labelling task in our project more useful for visualization to mark two linguistic could not be based on previous work done for EP, expressions as referring to the same participant. and it had to be done from scratch. The easier way Thus, our analysis only considers the proposed to do so was to use some established framework objectal links (objectalIdentity, partOf, subset, and adapt it to EP, but the methodology typically memberOf and referentialDisjunction) between used in frameworks designed for English (eg. discourse entities, which allows to represent FrameNet) requires that, for each verb, a frame be 2 compatible with Universal Dependencies, and that codifies The Universal Anaphora initiative (https://universalanaphora.github.io/UniversalAnaphora/) different aspects of the anaphoric phenomena. has been working towards a proposal markup scheme 5
constructed, and the construction of each frame particular part of SemAF by resorting to some entails many examples with the same verb and their notations from other parts of the ISO. Gaizauskas analysis (to identify all the meanings the verb can and Alrashid (2019), for instance, put forward a have and all the constructions in which it can scheme with some annotations from ISO-24617- occur), to determine its semantic selection. This 1/7, but do not refer to issues related to work would be colossal, and impracticable taking incompatibilities. Therefore, in the process of into account the time frame and objectives of the constructing our model, we had to overcome these project. Therefore, we needed a framework that difficulties in order to obtain a fully integrated would allow semantic annotation to be limited to scheme. the analysis of concrete examples of the news to be We began by modelling the types of structures annotated. We started working with the framework as entity structures and link structures, and defined provided by LIRICS, which was the most subtypes for each type, as described in Figure 1. appropriate for the task. Furthermore, as LIRICS was the basis for the construction of the ISO events standard for thematic annotation, there would be fewer potential problems when integrating Entity times structures semantic role annotation with referential and temporal annotation. participants Consequently, in our project, we annotate Multilayer semantic annotatin temporal semantic roles following ISO-24617-4 framework link specifications in what concerns semantic roles. We aspectual do not construct entity structures, nor event link structures in this level of annotation. Instead, we Link subordination link use the entity structures constructed in the structures referential annotation to deal with non- objectal link event discourse entities, and the entity structures constructed in the temporal annotation to deal semantic role link with event discourse entities. The semantic role annotation consists in establishing the thematic Figure 1: Text2story semantic annotation framework relation between predicates and their arguments and modifiers. 4.2 Harmonizing Different Layers This annotation structure is the first step to guarantee that all the layers are combined into a The foregoing describes how the markup language coherent annotation scheme. The entity structures, used in each layer of our annotation scheme was regardless of the layer to which they are associated, extracted from three different standards. Although are available to be related among them by different they comply with the principles for semantic types of link structures. Such unifying approach annotation (ISO-24617-6), in fact, they were facilitates a uniform semantic representation in elaborated separately and assynchronically, and discourse representation structures (DRS). they lack information about how to combine them The next step was to decide on the attributes and with each other. ISO-24617-6, in addition to their respective values, so the information they defining some overall guidelines for the semantic codified would be compatible and not repetitive, as annotation framework (SemAF), attempts at explained in the previous sections. The final tackling some overlaps and inconsistencies annotation scheme is presented in Table 1. between the different parts of the SemAF, but its coverage is limited. This means that, when combining different parts of the SemAF, as we did, it is expected that not only some incompatibilities may arise, but also some loose-ends and gaps may be left unsolved. Proposals such as Bunt (2019) improve the absence of some information in one 6
The harmonization of the different annotation ENTITY STRUCTURES layers using ISO-standards presented us with some class occurrence, state, reporting, mismatches between the three ISOs, which had to perception, aspectual, I- be addressed and solved. As an illustration, we action, I-state present two of those issues. type state, process, transition Concerning markables, while the thematic pos verb, noun, adjective, preposition annotation specifications in ISO 24617-4 foretold tense present, past, future, that a clause may receive a semantic role, the imperfect, none referential ISO does not stipulate any entity aspect progressive, perfective, structure for clauses. Our solution to this problem EVENTS imperfective, imperfective- progressive, perfective- was to mark the event structure corresponding to progressive, none the verbal predicate of the subordinated clause so vform none, gerundive, infinitive, that the semantic role link can be set up. participle Accordingly, in a sentence like John said that Mary mood none, subjunctive, went to Porto the chunk that is linked to “said” by conditional, future, the semantic role theme is not the whole clause, but imperative modality dever, poder, ter de, ser only the verb “went”, because it has been already capaz de associated to an entity structure, more precisely to polarity negative, positive an event structure, in the temporal layer, contrary type date, time, duration, set to the clause. This solution adopts a Neo- value specific value Davidsonian perspective of the relation between TIME temporal publication_time events and their arguments and considers that all function entities with an event structure annotated in the anchortime time ID (select relevant time) temporal level correspond to an event argument of lexical head noun, pronoun a predicate. So, in a Neo-Davidsonian version, the PARTICIPANTS individuation: set, individual, sentence above would have the following logical mass form: ∃e1 [SAY (e1) & AGENT (e1, John) & ∃e2 domain types: per, org, loc, obj, nat, [GO (∃e2) & AGENT (∃e2, Mary) & TO (∃e2, other Porto) & THEME (e1, e2)]]. involvement 0,1, >1, all, undefined However, some problems are of more difficult resolution. ISO-24617-4 envisages that some LINK STRUCTURES adverbial phrases may be attributed the semantic before, after, includes. role of manner, like “tightly” in the sentence The is_included, during, tiny stick was fastened tightly to his wrist (ISO- Temporal links simultaneous, identity, 24617: 23). Nonetheless, “tightly” in our begins, ends, begun_by, framework (and in the relevant ISO-standards, for ended_by initiates, culminates, that matter) cannot be marked as any kind of entity Aspectual links terminates, continues, structure. We could simply disregard it because it is reinitiates a modifier, but in some cases manner adverbial intensional, evidential, Subordination links neg_evidential, factive, phrases are complements (The child behaved counter_factive, conditional badly), conveying pertinent information to the objectalIdentity, partof, story, and, hence, they should be annotated. At this Objectal links subset, memberOf, moment, we still have no means to come to grips referentialDisjunction agent, source, location, with this conundrum. path, goal, time, theme, Despite the above-mentioned hurdles, we have instrument, partner, patient, been able to conciliate three ISO-standards and pivot, cause, beneficiary, produce a consistent and complete multilayer Semantic role links result, reason, purpose, manner, medium, means, semantic annotation scheme, which not only setting, initialLocation, adequately serves the purpose of our project, but finalLocation, distance, may also contribute to other annotations’ schemes. amount, attribute Table 1: Text2story annotation scheme 7 Table 1: Text2story annotation scheme Table 1: Text2story annotation scheme 1
5 An Annotated Example e6 simultaneous e4 In our model, the annotation procedure consists of SLINK three stages. Example (1) will serve to illustrate the e4 intensional e3 three stages. e6 intensional e4 (1) 20/03/2021 In the second stage, the participants are Cientistas que estudavam a erupção de um vulcão identified, and they are related to each other by da Islândia decidiram esta sexta-feira usar a lava objectal links. expelida da cratera para assar salsichas. Scientists that were studying the eruption of a PARTICIPANTS volcano of Iceland decided this Friday to use the p1=cientistas que estudavam a erupção de um lava expelled from the crater to roast sausages. vulcão na Islândia lexical head=noun individuation=individual type =per involvement= In the first stage, the annotator marks the entity >1 structures of events and times, and, then, the p2=que head=pronoun individuation=individual temporal, aspectual and subordination links are type =per involvement= >1 established. p3=um vulcão da Islândia head=noun individuation=individual type =per EVENTS involvement=1 e1=estudavam class=occurrence type=process p4=a lava expelida da cratera head=noun pos=verb tense=past aspect=imperfective individuation= mass type =nat involvement=1 polarity=pos vform=none mood=none p5= a lava head=noun individuation=mass e2=erupção class=occurrence type=process type=nat involvement= undef pos=noun tense= none aspect= none polarity= pos p6=a cratera head=noun individuation= individual vform=none mood=none type =nat involvement=1 e3=decidiram class=occurrence type=transition p7=salsichas head=noun individuation= individual pos=verb tense= past aspect=perfective polarity= type =obj involvement=>1 pos vform= none mood= none e4= usar class=occurrence type= process pos=verb OBJECTAL LINKS tense=none aspect=none polarity=pos p2 ObjIdentity p1 vform=infinitive mood= none p5 partOf p3 e5=expelida class=occurrence type=transition p6 partOf p3 pos=verb tense=past aspect= perfective polarity= pos vform=participle mood=none In the third stage, the annotator connects e6=assar class=occurrence type=process participants to events by semantic role links. pos=verb tense=none aspect=none polarity=pos vform= infinitive mood=none SEM_ROLE_LINK p1=agent (e3) TIME EXPRESSIONS p2=agent (e1) t1=20/03/2021 type=date value=20-03-2021 p3=patient (e2) FunctionInDocument= publication time p4=instrument (e4) t2=esta sexta-feira type=date value=19-03-2021 p5=theme (e5) AnchorTimeID=t1 p6=initial location (e5) p7=patient (e6) TLINK e6=purpose (e4) e2 before e1 p1=agent (e4) e3 is_included e1 p1=agent (e6) e3 is_included t1 e2=theme (e1) e4 after e3 e4=theme (e3) e5 before e3 8
After carrying out this manual annotation in the links available in the referential and thematic annotation tool BRAT 3 , our project’s pipeline layers. Likewise, a more detailed information includes two more modules: the Brat2DRS, which regarding quantification of participants and of takes the annotation file generated by Brat, parses events is a component to be improved in the future. it, and creates a DRS representation; and the At this moment, this kind of information has a very BRAT2Viz, which takes as input the DRS simplified representation solely in the referential representation, and deploys a web application that layer, which does not fully represent the different produces the visualizations in the form of MSC or possibilities of quantification over entities. KG (Amorim et al., 2021). Acknowledgments 6 Conclusion The authors wish to thank the reviewers for their constructive comments. This research is financed In this paper, we present an annotation framework by the ERDF – European Regional Development for news articles in EP that aims to provide the Fund through the North Portugal Regional input for visualization processes. First, we Operational Programme (NORTE 2020), under the determined what type of information was PORTUGAL 2020 and by National Funds through necessary to account for events and participants in the Portuguese funding agency, FCT - Fundação the narratives, and decided that three annotation para a Ciência e a Tecnologia within project layers - temporal, referential and thematic - were PTDC/CCI-COM/31857/2017 (NORTE-01-0145- required. The next step was to decide which tags FEDER-03185). The usual disclaimers apply. and links should be used in each layer to fulfill the annotation purposes. Since interoperability is References crucial when we talk about semantic resources, three standards ISO 24617-1/4/9 were utilized to Amorim, Evelin; Ribeiro, Alexandre; Cantante, Inês; Jorge, Alípio; Santana, Brenda; Nunes, Sérgio; create a multilayer semantic annotation scheme. Silvano, Purificação; Leal, António; & Campos, Notwithstanding the fact that these standards are, Ricardo (2021). Brat2Viz: a Tool and Pipeline for in fact, themselves three parts of the same standard, Visualizing Narratives from Annotated Texts. In when combined, some inconsistencies arise. So, we Text2Story 2021. Fourth International Workshop on had to harmonize the three layers, to attain a Narrative Extraction from Texts. (pp. 49-56). Lucca, cohesive annotation framework. Additionally, we Italy: CEUR Workshop Proceedings, CEUR- sought to balance the amount of information WS.org. needed to capture the news stories and the load of Bach, Emmon (1985). The algebra of events. the annotation process. Linguistics and Philosophy, 9, 5–16. Although this model was built to capture the Baker, Collin; Fillmore, Charles; & Lowe, John (1998). structure of stories in news in EP, its scope is not The Berkeley FrameNet project. In Proceedings of limited to news nor to EP, as it can be extended to the Conference on 36th Annual Meeting of the other narrative texts and other languages with some Association for Computational Linguistics and adaptations to deal with genre and language 17th International Conference on Computational specificities. Moreover, the integration of three Linguistics. (pp. 86–90). Montréal, Quebec: Université de Montréal. Retrieved from different layers in a single annotation framework https://www.aclweb.org/anthology/P98-1013/ enables formal semantic representation with DRS, which acts as an intermediate language to generate Basile, Valerio; Bos, Johan; Evang, Kilian; & visualizations in the form of knowledge graphs, for Venhuizen, Noortje J. (2012). Developing a large semantically annotated corpus. In Proceedings of instance. the Eighth International Conference on Language In the future, we intend to endow our annotation Resources and Evaluation. (pp. 3196–3200). scheme with more granularity. To this end, ISO Istanbul, Turkey: ELRA. Retrieved from standard for spatial information (ISO 24617-7) will https://www.aclweb.org/anthology/L12-1299/ be added to our framework. For now, spatial annotation has relied on the tags, attributes and 3 https://nabu.dcc.fc.up.pt/brat/#/examples_demos/paper_IS A-17 9
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