Quantitative learning strategies based on word networks

Learning English requires a considerable effort, but the way that vocabulary is introduced in textbooks is not optimized for learning efficiency. With the increasing population of English learners, learning process optimization will have significant impact and improvement towards English learning and teaching. The recent developments of big data analysis and complex network science provide additional opportunities to design and further investigate the strategies in English learning. In this paper, quantitative English learning strategies based on word network and word usage information are proposed. The strategies integrate the words frequency with topological structural information. By analyzing the influence of connected learned words, the learning weights for the unlearned words and dynamically updating of the network are studied and analyzed. The results suggest that quantitative strategies significantly improve learning efficiency while maintaining effectiveness. Especially, the optimized-weight-first strategy and segmented strategies outperform other strategies. The results provide opportunities for researchers and practitioners to reconsider the way of English teaching and designing vocabularies quantitatively by balancing the efficiency and learning costs based on the word network

Stock market sentiment lexicon acquisition using microblogging data and statistical measures

Lexicon acquisition is a key issue for sentiment analysis. This paper presents a novel and fast approach for creating stock market lexicons. The approach is based on statistical measures applied over a vast set of labeled messages from StockTwits, which is a specialized stock market microblog. We compare three adaptations of statistical measures, such as pointwise mutual information (PMI), two new complementary statistics and the use of sentiment scores for affirmative and negated con- texts. Using StockTwits, we show that the new lexicons are competitive for measuring investor sentiment when compared with six popular lexicons. We also applied a lexicon to easily produce Twitter investor sentiment indicators and analyzed their correlation with survey sentiment indexes. The new microblogging indicators have a moderate correlation with popular Investors Intelligence (II) and American Association of Individual Investors (AAII) indicators. Thus, the new microblogging approach can be used alternatively to traditional survey indicators with advantages (e.g., cheaper creation, higher frequencies).This work was supported by FCT - Funda ção para a Ciência e Tecnologia within the Project Scope UID/CEC/00319/201

The Impact of Sentiment Analysis Output on Decision Outcomes: An Empirical Evaluation

User-generated online content serves as a source of product- and service-related information that reduces the uncertainty in consumer decision making, yet the abundance of such content makes it prohibitively costly to use all relevant information. Dealing with this (big data) problem requires a consumer to decide what subset of information to focus on. Peer-generated star ratings are excellent tools for one to decide what subset of information to focus on as they indicate a review’s “tone”. However, star ratings are not available for all user-generated content and not detailed enough in other cases. Sentiment analysis, a text-analytic technique that automatically detects the polarity of text, provides sentiment scores that are comparable to, and potentially more refined than, star ratings. Despite its popularity as an active topic in analytics research, sentiment analysis outcomes have not been evaluated through rigorous user studies. We fill that gap by investigating the impact of sentiment scores on purchase decisions through a controlled experiment using 100 participants. The results suggest that, consistent with the effort-accuracy trade off and effort-minimization concepts, sentiment scores on review documents improve the efficiency (speed) of purchase decisions without significantly affecting decision effectiveness (confidence)

A sentiment analysis model to evaluate people’s opinion about artificial intelligence

Dissertation presented as the partial requirement for obtaining a Master's degree in Data Science and Advanced AnalyticsWith the use of internet, people are much more able to express and share what they think about a certain topic, their ideas and so on. Facebook and Twitter social networks, YouTube, online review sites like Zomato, online news sites or personal blogs are platforms that are usually used for this purpose. Every business wants to know what people think about their products; many people and politicians want to know the prediction for political elections; sometimes it can be useful to understand how opinions are distributed in some controversial themes. Thus, the analysis of textual data is also a need to stay competitive. In this work, through Sentiment Analysis techniques, different opinions from different online sources regarding to artificial intelligence are analyzed - a controversial field that have been a target of some debate in recent years. First, it is done a careful revision of the concept of Sentiment Analysis and all the involved techniques and processes such as data preprocessing, feature extraction and selection, sentiment classification approaches and machine learning algorithms – Naïve Bayes, Neural Networks, Random Forest, Support Vector Machine, Logistic Regression, Stochastic Gradient Descent. Based on previous works, the main conclusions, regarding to which techniques work better in which situations, are highlighted. Then, it is described the followed methodology in the application of Sentiment Analysis to artificial intelligence as a controversial field. The auxiliary tool used for this work is Python. In the end, results are presented and discussed