Isa Maks


2020

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Annotating Perspectives on Vaccination
Roser Morante | Chantal van Son | Isa Maks | Piek Vossen
Proceedings of the 12th Language Resources and Evaluation Conference

In this paper we present the Vaccination Corpus, a corpus of texts related to the online vaccination debate that has been annotated with three layers of information about perspectives: attribution, claims and opinions. Additionally, events related to the vaccination debate are also annotated. The corpus contains 294 documents from the Internet which reflect different views on vaccinations. It has been compiled to study the language of online debates, with the final goal of experimenting with methodologies to extract and contrast perspectives in the framework of the vaccination debate.

2017

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Storyteller: Visual Analytics of Perspectives on Rich Text Interpretations
Maarten van Meersbergen | Piek Vossen | Janneke van der Zwaan | Antske Fokkens | Willem van Hage | Inger Leemans | Isa Maks
Proceedings of the 2017 EMNLP Workshop: Natural Language Processing meets Journalism

Complexity of event data in texts makes it difficult to assess its content, especially when considering larger collections in which different sources report on the same or similar situations. We present a system that makes it possible to visually analyze complex event and emotion data extracted from texts. We show that we can abstract from different data models for events and emotions to a single data model that can show the complex relations in four dimensions. The visualization has been applied to analyze 1) dynamic developments in how people both conceive and express emotions in theater plays and 2) how stories are told from the perspectyive of their sources based on rich event data extracted from news or biographies.

2016

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GRaSP: A Multilayered Annotation Scheme for Perspectives
Chantal van Son | Tommaso Caselli | Antske Fokkens | Isa Maks | Roser Morante | Lora Aroyo | Piek Vossen
Proceedings of the Tenth International Conference on Language Resources and Evaluation (LREC'16)

This paper presents a framework and methodology for the annotation of perspectives in text. In the last decade, different aspects of linguistic encoding of perspectives have been targeted as separated phenomena through different annotation initiatives. We propose an annotation scheme that integrates these different phenomena. We use a multilayered annotation approach, splitting the annotation of different aspects of perspectives into small subsequent subtasks in order to reduce the complexity of the task and to better monitor interactions between layers. Currently, we have included four layers of perspective annotation: events, attribution, factuality and opinion. The annotations are integrated in a formal model called GRaSP, which provides the means to represent instances (e.g. events, entities) and propositions in the (real or assumed) world in relation to their mentions in text. Then, the relation between the source and target of a perspective is characterized by means of perspective annotations. This enables us to place alternative perspectives on the same entity, event or proposition next to each other.

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Unshared Task at the 3rd Workshop on Argument Mining: Perspective Based Local Agreement and Disagreement in Online Debate
Chantal van Son | Tommaso Caselli | Antske Fokkens | Isa Maks | Roser Morante | Lora Aroyo | Piek Vossen
Proceedings of the Third Workshop on Argument Mining (ArgMining2016)

2014

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Generating Polarity Lexicons with WordNet propagation in 5 languages
Isa Maks | Ruben Izquierdo | Francesca Frontini | Rodrigo Agerri | Piek Vossen | Andoni Azpeitia
Proceedings of the Ninth International Conference on Language Resources and Evaluation (LREC'14)

In this paper we focus on the creation of general-purpose (as opposed to domain-specific) polarity lexicons in five languages: French, Italian, Dutch, English and Spanish using WordNet propagation. WordNet propagation is a commonly used method to generate these lexicons as it gives high coverage of general purpose language and the semantically rich WordNets where concepts are organised in synonym , antonym and hyperonym/hyponym structures seem to be well suited to the identification of positive and negative words. However, WordNets of different languages may vary in many ways such as the way they are compiled, the number of synsets, number of synonyms and number of semantic relations they include. In this study we investigate whether this variability translates into differences of performance when these WordNets are used for polarity propagation. Although many variants of the propagation method are developed for English, little is known about how they perform with WordNets of other languages. We implemented a propagation algorithm and designed a method to obtain seed lists similar with respect to quality and size, for each of the five languages. We evaluated the results against gold standards also developed according to a common method in order to achieve as less variance as possible between the different languages.

2013

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Sentiment Analysis of Reviews: Should we analyze writer intentions or reader perceptions?
Isa Maks | Piek Vossen
Proceedings of the International Conference Recent Advances in Natural Language Processing RANLP 2013

2012

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Building a fine-grained subjectivity lexicon from a web corpus
Isa Maks | Piek Vossen
Proceedings of the Eighth International Conference on Language Resources and Evaluation (LREC'12)

In this paper we propose a method to build fine-grained subjectivity lexicons including nouns, verbs and adjectives. The method, which is applied for Dutch, is based on the comparison of word frequencies of three corpora: Wikipedia, News and News comments. Comparison of the corpora is carried out with two measures: log-likelihood ratio and a percentage difference calculation. The first step of the method involves subjectivity identification, i.e. determining if a word is subjective or not. The second step aims at the identification of more fine-grained subjectivity which is the distinction between actor subjectivity and speaker / writer subjectivity. The results suggest that this approach can be usefully applied producing subjectivity lexicons of high quality.

2011

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A verb lexicon model for deep sentiment analysis and opinion mining applications
Isa Maks | Piek Vossen
Proceedings of the 2nd Workshop on Computational Approaches to Subjectivity and Sentiment Analysis (WASSA 2.011)

2010

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Annotation Scheme and Gold Standard for Dutch Subjective Adjectives
Isa Maks | Piek Vossen
Proceedings of the Seventh International Conference on Language Resources and Evaluation (LREC'10)

Many techniques are developed to derive automatically lexical resources for opinion mining. In this paper we present a gold standard for Dutch adjectives developed for the evaluation of these techniques. In the first part of the paper we introduce our annotation guidelines. They are based upon guidelines recently developed for English which annotate subjectivity and polarity at word sense level. In addition to subjectivity and polarity we propose a third annotation category: that of the attitude holder. The identity of the attitude holder is partly implied by the word itself and may provide useful information for opinion mining systems. In the second part of paper we present the criteria adopted for the selection of items which should be included in this gold standard. Our design is aimed at an equal representation of all dimensions of the lexicon , like frequency and polysemy, in order to create a gold standard which can be used not only for benchmarking purposes but also may help to improve in a systematic way, the methods which derive the word lists. Finally we present the results of the annotation task including annotator agreement rates and disagreement analysis.

2008

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Integrating Lexical Units, Synsets and Ontology in the Cornetto Database
Piek Vossen | Isa Maks | Roxane Segers | Hennie VanderVliet
Proceedings of the Sixth International Conference on Language Resources and Evaluation (LREC'08)

Cornetto is a two-year Stevin project (project number STE05039) in which a lexical semantic database is built that combines Wordnet with Framenet-like information for Dutch. The combination of the two lexical resources (the Dutch Wordnet and the Referentie Bestand Nederlands) will result in a much richer relational database that may improve natural language processing (NLP) technologies, such as word sense-disambiguation, and language-generation systems. In addition to merging the Dutch lexicons, the database is also mapped to a formal ontology to provide a more solid semantic backbone. Since the database represents different traditions and perspectives of semantic organization, a key issue in the project is the alignment of concepts across the resources. This paper discusses our methodology to first automatically align the word meanings and secondly to manually revise the most critical cases.

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Adjectives in the Dutch Semantic Lexical Database CORNETTO
Isa Maks | Piek Vossen | Roxane Segers | Hennie van der Vliet
Proceedings of the Sixth International Conference on Language Resources and Evaluation (LREC'08)

The goal of this paper is to describe how adjectives are encoded in Cornetto, a semantic lexical database for Dutch. Cornetto combines two existing lexical resources with different semantic organisation, i.e. Dutch Wordnet (DWN) with a synset organisation and Referentie Bestand Nederlands (RBN) with an organisation in Lexical Units. Both resources will be aligned and mapped on the formal ontology SUMO. In this paper, we will first present details of the description of adjectives in each of the the two resources. We will then address the problems that are encountered during alignment to the SUMO ontology which are greatly due to the fact that SUMO has never been tested for its adequacy with respect to adjectives. We contrasted SUMO with an existing semantic classification which resulted in a further refined and extended SUMO geared for the description of adjectives.

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Standardising Bilingual Lexical Resources According to the Lexicon Markup Framework
Isa Maks | Carole Tiberius | Remco van Veenendaal
Proceedings of the Sixth International Conference on Language Resources and Evaluation (LREC'08)

The Dutch HLT agency for language and speech technology (known as TST-centrale) at the Institute for Dutch Lexicology is responsible for the maintenance, distribution and accessibility of (Dutch) digital language resources. In this paper we present a project which aims to standardise the format of a set of bilingual lexicons in order to make them available to potential users, to facilitate the exchange of data (among the resources and with other (monolingual) resources) and to enable reuse of these lexicons for NLP applications like machine translation and multilingual information retrieval. We pay special attention to the methods and tools we used and to some of the problematic issues we encountered during the conversion process. As these problems are mainly caused by the fact that the standard LMF model fails in representing the detailed semantic and pragmatic distinctions made in our bilingual data, we propose some modifications to the standard. In general, we think that a standard for lexicons should provide a model for bilingual lexicons that is able to represent all detailed and fine-grained translation information which is generally found in these types of lexicons.

2006

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Exploring opportunities for Comparability and Enrichment by Linking lexical databases
Isa Maks | Bob Boelhouwer
Proceedings of the Fifth International Conference on Language Resources and Evaluation (LREC’06)

Results are presented of an ongoing project of the Dutch TST-centre for language and speech technology aiming at linking of various lexical databases. The project involves four Dutch monolingual lexicons: WlNT05, e-Lex, RBN and RBBN. These databases differ in organisational structure and content. To enable linkage between these lexicons, we developed a common feature value set and a common organisational structure. Both are based upon existing standards for the creation and reusability of lexicons: the Lexical Markup Framework and the EAGLES standard. Examples of the content and structure of each of the lexical databases are presented in their original form. Also, the structure and content is shown when mapped onto the common framework and feature value set. Thus, the commonalities and the complementarity of the lexical databases are more readily apparent. Besides, this elaboration of the databases opens up the opportunity for mutual enrichment.

1996

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MULTITALE: linking medical concepts by means of frames
Isa Maks | Willy Martin
COLING 1996 Volume 2: The 16th International Conference on Computational Linguistics