This paper proposes an audience selection framework for online brand advertising based on user activities on social media platforms. It is one of the first studies to our knowledge that develops and analyzes implicit brand-brand networks for online brand advertising. This paper makes several contributions. We first extract and analyze implicit weighted brand-brand networks, representing interactions among users and brands, from a large dataset. We examine network properties and community structures and propose a framework combining text and network analyses to find target audiences. As a part of this framework, we develop a hierarchical community detection algorithm to identify a set of brands that are closely related to a specific brand. This latter brand is referred to as the "focal brand." We also develop a global ranking algorithm to calculate brand influence and select influential brands from this set of closely related brands. This is then combined with sentiment analysis to identify target users from these selected brands. To process large-scale datasets and networks, we implement several MapReduce-based algorithms. Finally, we design a novel evaluation technique to test the effectiveness of our targeting framework. Experiments conducted with Facebook data show that our framework provides significant performance improvements in identifying target audiences for focal brands.

With the rapid growth and maturity of Question-Answering (QA) domain, non-factoid Question-Answering tasks are in high demand. However, existing Question-Answering systems are either fact-based, or highly keyword related and hard-coded. Moreover, if QA is to become more personable, sentiment of the question and answer should be taken into account. However, there is not much research done in the field of non-factoid Question-Answering systems based on sentiment analysis, that would enable a system to retrieve answers in a more emotionally intelligent way. This study investigates to what extent could prediction of the best answer be improved by adding an extended representation of sentiment information into non-factoid Question-Answering.

L'analyse de sentiments est un des nouveaux défis apparus en traitement automatique des langues avec l'avènement des réseaux sociaux sur le WEB. Profitant de la quantité d'information maintenant disponible, la recherche et l'industrie se sont mises en quête de moyens pour analyser automatiquement les opinions exprimées dans les textes. Pour nos travaux, nous nous plaçons dans un contexte multilingue et multi-domaine afin d'explorer la classification automatique et adaptative de polarité.Nous proposons dans un premier temps de répondre au manque de ressources lexicales par une méthode de construction automatique de lexiques affectifs multilingues à partir de microblogs. Pour valider notre approche, nous avons collecté plus de 2 millions de messages de Twitter, la plus grande plate-forme de microblogging et avons construit à partir de ces données des lexiques affectifs pour l'anglais, le français, l'espagnol et le chinois.Pour une meilleure analyse des textes, nous proposons aussi de remplacer le traditionnel modèle n-gramme par une représentation à base d'arbres de dépendances syntaxiques. Dans notre modèles, les n-grammes ne sont plus construits à partir des mots mais des triplets constitutifs des dépendances syntaxiques. Cette manière de procéder permet d'éviter la perte d'information que l'on obtient avec les approches classiques à base de sacs de mots qui supposent que les mots sont indépendants.Finalement, nous étudions l'impact que les traits spécifiques aux entités nommées ont sur la classification des opinions minoritaires et proposons une méthode de normalisation des décomptes d'observables, qui améliore la classification de ce type d'opinion en renforçant le poids des termes affectifs.Nos propositions ont fait l'objet d'évaluations quantitatives pour différents domaines d'applications (les films, les revues de produits commerciaux, les nouvelles et les blogs) et pour plusieurs langues (anglais, français, russe, espagnol et chinois), avec en particulier une participation officielle à plusieurs campagnes d'évaluation internationales (SemEval 2010, ROMIP 2011, I2B2 2011). / Sentiment analysis is a challenging task today for computational linguistics. Because of the rise of the social Web, both the research and the industry are interested in automatic processing of opinions in text. In this work, we assume a multilingual and multidomain environment and aim at automatic and adaptive polarity classification.We propose a method for automatic construction of multilingual affective lexicons from microblogging to cover the lack of lexical resources. To test our method, we have collected over 2 million messages from Twitter, the largest microblogging platform, and have constructed affective resources in English, French, Spanish, and Chinese.We propose a text representation model based on dependency parse trees to replace a traditional n-grams model. In our model, we use dependency triples to form n-gram like features. We believe this representation covers the loss of information when assuming independence of words in the bag-of-words approach.Finally, we investigate the impact of entity-specific features on classification of minor opinions and propose normalization schemes for improving polarity classification. The proposed normalization schemes gives more weight to terms expressing sentiments and lower the importance of noisy features.The effectiveness of our approach has been proved in experimental evaluations that we have performed across multiple domains (movies, product reviews, news, blog posts) and multiple languages (English, French, Russian, Spanish, Chinese) including official participation in several international evaluation campaigns (SemEval'10, ROMIP'11, I2B2'11).

This thesis explores the possibility of applying sentiment analysis to extract tonality of user reviews on the Nordic languages. Data processing is performed in the form of preprocessing through tokenization and padding. A model is built in a framework called Keras. Models for classification and regression were built using LSTM and GRU architectures. The results showed how the dataset influences the end result and the correlation between observed and predicted values for classification and regression. The project shows that it is possible to implement NLP in the Nordic languages and how limitations in input and performance in hardware affected the result. Some questions that arose during the project consist of methods for improving the dataset and alternative solutions for managing information related to big data and GDPR. / Denna avhandling undersöker möjligheten att tillämpa sentiment analys för att extrahera tonalitet av användarrecensioner på nordiska språk. Databehandling utförs i form av förprocessering genom tokenisering och padding. En modell är uppbyggd i en ramverkad Keras. Modeller för klassificering och regression byggdes med LSTM och GRU-arkitekturer. Resultaten visade hur datasetet påverkar slutresultatet och korrelationen mellan observerade och förutspådda värden för klassificering och regression. Projektet visar att det är möjligt att implementera NLP på de nordiska språken och hur begränsningar i input och prestanda i hårdvara påverkat resultatet. Några frågor som uppstod under projektet består av metoder för att förbättra datasetet och alternativa lösningar för hantering av information relaterad till stora data och GDPR.

O grande volume de dados que temos disponíveis em ambientes virtuais pode ser excelente fonte de novos recursos para estudos em diversas tarefas de Processamento de Linguagem Natural, como a Análise de Sentimentos. Infelizmente é elevado o custo de anotação de novos córpus, que envolve desde investimentos financeiros até demorados processos de revisão. Nossa pesquisa propõe uma abordagem de anotação semissupervisionada, ou seja, anotação automática de um grande córpus não anotado partindo de um conjunto de dados anotados manualmente. Para tal, introduzimos o TweetSentBR, um córpus de tweets no domínio de programas televisivos que possui anotação em três classes e revisões parciais feitas por até sete anotadores. O córpus representa um importante recurso linguístico de português brasileiro, e fica entre os maiores córpus anotados na literatura para classificação de polaridades. Além da anotação manual do córpus, realizamos a implementação de um framework de aprendizado semissupervisionado que faz uso de dados anotados e, de maneira iterativa, expande o mesmo usando dados não anotados. O TweetSentBR, que possui 15:000 tweets anotados é assim expandido cerca de oito vezes. Para a expansão, foram treinados modelos de classificação usando seis classificadores de polaridades, assim como foram avaliados diferentes parâmetros e representações a fim de obter um córpus confiável. Realizamos experimentos gerando córpus expandidos por cada classificador, tanto para a classificação em três polaridades (positiva, neutra e negativa) quanto para classificação binária. Avaliamos os córpus gerados usando um conjunto de held-out e comparamos a FMeasure da classificação usando como treinamento os córpus anotados manualmente e semiautomaticamente. O córpus semissupervisionado que obteve os melhores resultados para a classificação em três polaridades atingiu 62;14% de F-Measure média, superando a média obtida com as avaliações no córpus anotado manualmente (61;02%). Na classificação binária, o melhor córpus expandido obteve 83;11% de F1-Measure média, superando a média obtida na avaliação do córpus anotado manualmente (79;80%). Além disso, simulamos nossa expansão em córpus anotados da literatura, medindo o quão corretas são as etiquetas anotadas semi-automaticamente. Nosso melhor resultado foi na expansão de um córpus de reviews de produtos que obteve FMeasure de 93;15% com dados binários. Por fim, comparamos um córpus da literatura obtido por meio de supervisão distante e nosso framework semissupervisionado superou o primeiro na classificação de polaridades binária em cross-domain. / The high volume of data available in the Internet can be a good resource for studies of several tasks in Natural Language Processing as in Sentiment Analysis. Unfortunately there is a high cost for the annotation of new corpora, involving financial support and long revision processes. Our work proposes an approach for semi-supervised labeling, an automatic annotation of a large unlabeled set of documents starting from a manually annotated corpus. In order to achieve that, we introduced TweetSentBR, a tweet corpora on TV show programs domain with annotation for 3-point (positive, neutral and negative) sentiment classification partially reviewed by up to seven annotators. The corpus is an important linguistic resource for Brazilian Portuguese language and it stands between the biggest annotated corpora for polarity classification. Beyond the manual annotation, we implemented a semi-supervised learning based framework that uses this labeled data and extends it using unlabeled data. TweetSentBR corpus, containing 15:000 documents, had its size augmented in eight times. For the extending process, we trained classification models using six polarity classifiers, evaluated different parameters and representation schemes in order to obtain the most reliable corpora. We ran experiments generating extended corpora for each classifier, both for 3-point and binary classification. We evaluated the generated corpora using a held-out subset and compared the obtained F-Measure values with the manually and the semi-supervised annotated corpora. The semi-supervised corpus that obtained the best values for 3-point classification achieved 62;14% on average F-Measure, overcoming the results obtained by the same classification with the manually annotated corpus (61;02%). On binary classification, the best extended corpus achieved 83;11% on average F-Measure, overcoming the results on the manually corpora (79;80%). Furthermore, we simulated the extension of labeled corpora in literature, measuring how well the semi-supervised annotation works. Our best results were in the extension of a product review corpora, achieving 93;15% on F1-Measure. Finally, we compared a literature corpus which was labeled by using distant supervision with our semi-supervised corpus, and this overcame the first in binary polarity classification on cross-domain data.

Instagram is one of the main social platforms for business promotion. Millions of potential customers and endless visual marketing opportunities makes Instagram a perfect place to increase online sales. There are many tools and mechanisms to promote brands on Instagram such as paid advertising or using a pre-generated set of popular hashtags. In this regard, the presence and content of users’ comments becomes an important socio-psychological factor in the motivation to buy or use a product or service. The goal of this degree project is to investigate natural language processing techniques applied to users’ comments on Instagram in order to determine a new algorithm that will include content analysis to the list of feed ranking factors. As it is now, the user has to read through posts on Instagram to get an idea of the quality of a product or service. Therefore, a way to classify and rank products and services is needed. We propose a new algorithm called "Wed 2.0" that can assist consumers in their search of wedding services and products on Instagram. Data mining techniques and sentiment analysis are used to define the mood of the comments and structure user opinions as well as to rank accounts based on this knowledge.

Religious belief and attendance predict improved well-being at the individual level. Paradoxically, geographic locations with high rates of religious belief and attendance are often those with the differentially high rates of societal instability and suffering. Many of the consequences of religiosity are context-based and vary across time, and holy days are naturally-occurring religious cues that have been shown to influence religiously-relevant attitudes and behaviors. I investigated the degree to which personal religiosity and religious geography (i.e. religious demographics with other location variables) individually and interactively predict well-being across days of the week. In the first study, American Christians demonstrated greater well-being by expressing more positive sentiment in Twitter posts, while American Muslims displayed less well-being. Sundays were generally the most positive day, but American Muslims communicated more happiness on Fridays (the Muslim holy day). In the second study, Christianity did not predict increased well-being in the posts of college students. In the third study, global survey data with measures of religiosity and well-being indicated that the well-being consequences of religious affiliation depend on the religious group and location, and that people tend to be especially positive on their group’s holy day. Study four explored the latent topical content of Twitter posts. Across studies, religious minority status appeared to have a deleterious effect on well-being.

Com a crescente expansão da Web, cada vez mais usuários compartilham suas opiniões sobre experiências vividas. Essas opiniões estão, na maioria das vezes, representadas sob a forma de texto não estruturado. A Análise de Sentimentos (ou Mineração de Opinião) é a área dedicada ao estudo computacional das opiniões e sentimentos expressos em textos, tipicamente classificando-os de acordo com a sua polaridade (i.e., como positivos ou negativos). Ao mesmo tempo em que sites de vendas e redes sociais tornam-se grandes fontes de opiniões, cresce a busca por ferramentas que, de forma automática, classifiquem as opiniões e identifiquem a qual aspecto da entidade avaliada elas se referem. Neste trabalho, propomos métodos direcionados a dois pontos fundamentais para o tratamento dessas opiniões: (i) análise de sentimentos baseada em aspectos e (ii) atribuição de polaridade. Para a análise de sentimentos baseada em aspectos, desenvolvemos um método que identifica expressões que mencionem aspectos e entidades em um texto, utilizando ferramentas de processamento de linguagem natural combinadas com algoritmos de aprendizagem de máquina. Para a atribuição de polaridade, desenvolvemos um método que utiliza 24 atributos extraídos a partir do ranking gerado por um motor de busca e para gerar modelos de aprendizagem de máquina. Além disso, o método não depende de recursos linguísticos e pode ser aplicado sobre dados com ruídos. Experimentos realizados sobre datasets reais demonstram que, em ambas as contribuições, conseguimos resultados próximos aos dos baselines mesmo com um número pequeno de atributos. Ainda, para a atribuição de polaridade, os resultados são comparáveis aos de métodos do estado da arte que utilizam técnicas mais complexas. / With the growing expansion of the Web, more and more users share their views on experiences they have had. These views are, in most cases, represented in the form of unstructured text. The Sentiment Analysis (or Opinion Mining) is a research area dedicated to the computational study of the opinions and feelings expressed in texts, typically categorizing them according to their polarity (i.e., as positive or negative). As on-line sales and social networking sites become great sources of opinions, there is a growing need for tools that classify opinions and identify to which aspect of the evaluated entity they refer to. In this work, we propose methods aimed at two key points for the treatment of such opinions: (i) aspect-based sentiment analysis and (ii) polarity assignment. For aspect-based sentiment analysis, we developed a method that identifies expressions mentioning aspects and entities in text, using natural language processing tools combined with machine learning algorithms. For the identification of polarity, we developed a method that uses 24 attributes extracted from the ranking generated by a search engine to generate machine learning models. Furthermore, the method does not rely on linguistic resources and can be applied to noisy data. Experiments on real datasets show that, in both contributions, our results using a small number of attributes were similar to the baselines. Still, for assigning polarity, the results are comparable to prior art methods that use more complex techniques.

A análise de contradições é uma área relativamente nova, multidisciplinar e complexa que tem por objetivo principal identificar pedaços contraditórios de texto. Ela pode ser abordada a partir das perspectivas de diferentes áreas de pesquisa, tais como processamento de linguagem natural, mineração de opinioes, recuperação de informações e extração de Informações. Este trabalho foca no problema de detectar contradições em textos – mais especificamente, nas contradições que são o resultado da diversidade de sentimentos entre as sentenças de um determinado texto. Ao contrário de outros tipos de contradições, a detecção de contradições baseada em sentimentos pode ser abordada como uma etapa de pós-processamento na tarefa tradicional de análise de sentimentos. Neste contexto, este trabalho apresenta duas contribuições principais. A primeira é um estudo exploratório da tarefa de classificação, na qual identificamos e usamos diferentes ferramentas e recursos. A segunda contribuição é a adaptação e a extensão de um framework de análise contradição existente, filtrando seus resultados para remover os comentários erroneamente rotulados como contraditórios. O método de filtragem baseia-se em dois algoritmos simples de similaridade entre palavras. Uma avaliação experimental em comentários sobre produtos reais mostrou melhorias proporcionais de até 30 % na acurácia da classificação e 26 % na precisão da detecção de contradições. / Contradiction Analysis is a relatively new multidisciplinary and complex area with the main goal of identifying contradictory pieces of text. It can be addressed from the perspectives of different research areas such as Natural Language Processing, Opinion Mining, Information Retrieval, and Information Extraction. This work focuses on the problem of detecting sentiment-based contradictions which occur in the sentences of a given review text. Unlike other types of contradictions, the detection of sentiment-based contradictions can be tackled as a post-processing step in the traditional sentiment analysis task. In this context, we make two main contributions. The first is an exploratory study of the classification task, in which we identify and use different tools and resources. Our second contribution is adapting and extending an existing contradiction analysis framework by filtering its results to remove the reviews that are erroneously labeled as contradictory. The filtering method is based on two simple term similarity algorithms. An experimental evaluation on real product reviews has shown proportional improvements of up to 30% in classification accuracy and 26% in the precision of contradiction detection.

Detecção de posicionamento é a tarefa de automaticamente identificar se o autor de um texto é favorável, contrário, ou nem favorável e nem contrário a uma dada proposição ou alvo. Com o amplo uso do Twitter como plataforma para expressar opiniões e posicionamentos, a análise automatizada deste conteúdo torna-se de grande valia para empresas, organizações e figuras públicas. Em geral, os trabalhos que exploram tal tarefa adotam abordagens supervisionadas ou semi-supervisionadas. O presente trabalho propõe e avalia um processo não supervisionado de detecção de posicionamento em textos de tweets que tem como entrada apenas o alvo e um conjunto de tweets a rotular e é baseado em uma abordagem híbrida composta por 2 etapas: a) rotulação automática de tweets baseada em um conjunto de heurísticas e b) classificação complementar baseada em aprendizado supervisionado de máquina. A proposta tem êxito quando aplicada a figuras públicas, superando o estado-da-arte. Além disso, são avaliadas alternativas no intuito de melhorar seu desempenho quando aplicada a outros domínios, revelando a possibilidade de se empregar estratégias tais como o uso de alvos e perfis semente dependendo das características de cada domínio. / Stance Detection is the task of automatically identifying if the author of a text is in favor of the given target, against the given target, or whether neither inference is likely. With the wide use of Twitter as a platform to express opinions and stances, the automatic analysis of this content becomes of high regard for companies, organizations and public figures. In general, works that explore such task adopt supervised or semi-supervised approaches. The present work proposes and evaluates a non-supervised process to detect stance in texts of tweets that has as entry only the target and a set of tweets to classify and is based on a hybrid approach composed by 2 stages: a) automatic labelling of tweets based on a set of heuristics and b) complementary classification based on supervised machine learning. The proposal succeeds when applied to public figures, overcoming the state-of-the-art. Beyond that, some alternatives are evaluated with the intention of increasing the performance when applied to other domains, revealing the possibility of use of strategies such as using seed targets and profiles depending on each domain characteristics.