Generation of resources for Sentiment Analysis in Spanish

Tesis doctoral en Informática realizada por Mª Dolores Molina en la Universidad de Jaén (UJA) bajo la dirección de la doctora Mª Teresa Martín Valdivia (UJA). El acto de defensa de la tesis tuvo lugar en Jaén el 28 de noviembre de 2014 ante el tribunal formado por los doctores Luis Alfonso Ureña (UJA), Rafael Muñoz (UA) y Fermín Cruz (U. Sevilla). La calificación obtenida fue Sobresaliente Cum Laude por unanimidad.Ph.D. Thesis in Computer Science written by Mª Dolores Molina at the University of Jaén (UJA), under the supervision of Dr. Mª Teresa Martín (UJA). The author was examined on 28th of November 2014 at the University of Jaen by a commission composed by the doctors Luis Alfonso Ureña (UJA), Rafael Muñoz (UA) and Fermín Cruz (U. Sevilla). The unanimously awarded grade was Excellent Cum Laude

Universal, Unsupervised (Rule-Based), Uncovered Sentiment Analysis

We present a novel unsupervised approach for multilingual sentiment analysis driven by compositional syntax-based rules. On the one hand, we exploit some of the main advantages of unsupervised algorithms: (1) the interpretability of their output, in contrast with most supervised models, which behave as a black box and (2) their robustness across different corpora and domains. On the other hand, by introducing the concept of compositional operations and exploiting syntactic information in the form of universal dependencies, we tackle one of their main drawbacks: their rigidity on data that are structured differently depending on the language concerned. Experiments show an improvement both over existing unsupervised methods, and over state-of-the-art supervised models when evaluating outside their corpus of origin. Experiments also show how the same compositional operations can be shared across languages. The system is available at http://www.grupolys.org/software/UUUSA/Comment: 19 pages, 5 Tables, 6 Figures. This is the authors version of a work that was accepted for publication in Knowledge-Based System

Generación de recursos para Análisis de Opiniones en español

[ES] El Análisis de Sentimientos (AS) se refiere al tratamiento de la información subjetiva en los textos, sobretodo comentarios u opiniones personales. Una de las tareas básicas de AS es la clasificación de la polaridad de un texto determinado en un documento o frase, es decir, si la opinión expresada es positiva, negativa o neutra. Mucho se ha investigado en la clasificación de polaridad en documentos escritos en inglés. Sin embargo, actualmente cada vez más personas expresan comentarios u opiniones en su propio idioma. Para llevar a cabo esta labor es necesario el uso de los recursos lingüísticos (lexicones y corpora) que son escasos, cuando no inexistentes, en idiomas distintos al inglés. Por tales circunstancias, esta tesis tiene como objetivo la generación de nuevos recursos para el AS en español, tercer idioma con más relevancia en la web 2.0.[EN] Sentiment Analysis (SA) refers to the treatment of the subjective information in texts, product reviews, comments on blogs or personal opinions. One of the basic tasks in SA is classifying the polarity of a given text in a document, i.e., whether the opinion expressed is positive, negative, or neutral. Many studies have investigated the polarity classification in documents written in English. However, nowadays more and more people express their comments, opinions or points of view in their own language. For this reason, it is necessary to develop systems than can extract and analyze all this information in different languages. In this work we focus on polarity detection for Spanish reviews. We are mainly concerned with linguistic resources for Spanish sentiment analysis because, in addition to the lack of resources for this language in this area, it is currently the third most used language in the web 2.0.Tesis Univ. Jaén. Departamento de Informática- Leída el 28 de noviembre de 201

The Taming of the Shrew - non-standard text processing in the Digital Humanities

Natural language processing (NLP) has focused on the automatic processing of newspaper texts for many years. With the growing importance of text analysis in various areas such as spoken language understanding, social media processing and the interpretation of text material from the humanities, techniques and methodologies have to be reviewed and redefined since so called non-standard texts pose challenges on the lexical and syntactic level especially for machine-learning-based approaches. Automatic processing tools developed on the basis of newspaper texts show a decreased performance for texts with divergent characteristics. Digital Humanities (DH) as a field that has risen to prominence in the last decades, holds a variety of examples for this kind of texts. Thus, the computational analysis of the relationships of Shakespeare’s dramatic characters requires the adjustment of processing tools to English texts from the 16th-century in dramatic form. Likewise, the investigation of narrative perspective in Goethe’s ballads calls for methods that can handle German verse from the 18th century. In this dissertation, we put forward a methodology for NLP in a DH environment. We investigate how an interdisciplinary context in combination with specific goals within projects influences the general NLP approach. We suggest thoughtful collaboration and increased attention to the easy applicability of resulting tools as a solution for differences in the store of knowledge between project partners. Projects in DH are not only constituted by the automatic processing of texts but are usually framed by the investigation of a research question from the humanities. As a consequence, time limitations complicate the successful implementation of analysis techniques especially since the diversity of texts impairs the transferability and reusability of tools beyond a specific project. We answer to this with modular and thus easily adjustable project workflows and system architectures. Several instances serve as examples for our methodology on different levels. We discuss modular architectures that balance time-saving solutions and problem-specific implementations on the example of automatic postcorrection of the output text from an optical character recognition system. We address the problem of data diversity and low resource situations by investigating different approaches towards non-standard text processing. We examine two main techniques: text normalization and tool adjustment. Text normalization aims at the transformation of non-standard text in order to assimilate it to the standard whereas tool adjustment concentrates on the contrary direction of enabling tools to successfully handle a specific kind of text. We focus on the task of part-of-speech tagging to illustrate various approaches toward the processing of historical texts as an instance for non-standard texts. We discuss how the level of deviation from a standard form influences the performance of different methods. Our approaches shed light on the importance of data quality and quantity and emphasize the indispensability of annotations for effective machine learning. In addition, we highlight the advantages of problem-driven approaches where the purpose of a tool is clearly formulated through the research question. Another significant finding to emerge from this work is a summary of the experiences and increased knowledge through collaborative projects between computer scientists and humanists. We reflect on various aspects of the elaboration and formalization of research questions in the DH and assess the limitations and possibilities of the computational modeling of humanistic research questions. An emphasis is placed on the interplay of expert knowledge with respect to a subject of investigation and the implementation of tools for that purpose and the thereof resulting advantages such as the targeted improvement of digital methods through purposeful manual correction and error analysis. We show obstacles and chances and give prospects and directions for future development in this realm of interdisciplinary research