[This post is based on the BSc. Thesis of Enya Nieland and the BSc. Thesis of Quinten van Langen (Information Science Track)]
The Web is a rich source of information that presents events, facts and their evolution across time. People mainly follow events through news articles or through social media, such as Twitter. The main goal of the two bachelor projects was to see whether topics in news articles or tweets can be represented in a concentric model where the main concepts describing the topic are placed in a “core”, and the concepts less relevant are placed in a “crust”. In order to answer to this question, Enya and Quinten addressed the research conducted by José Luis Redondo García et al. in the paper “The Concentric Nature of News Semantic Snapshots”.
Enya focused on the tweets dataset and her results show that the approach presented in the aforementioned paper does not work well for tweets. The model had a precision score of only 0.56. After a data inspection, Enya concluded that the high amount of redundant information found in tweets, make them difficult to summarise and identify the most relevant concepts. Thus, after applying stemming and lemmatisation techniques, data cleaning and similarity scores together with various relevance thresholds, she improved the precision to 0.97.
Quinten focused on topics published in news articles. When applying the method described in the reference article, Quinten concluded that relevant entities from news articles can be indeed identified. However, his focus was also to identify the most relevant events that are mentioned when talking about a topic. As an addition, he calculated a term frequency inverse document frequency (TF-IDF) score and an event-relation (temporal relations and event-related concepts) score for each topic. These combined scores determines the new relevance score of the entities mentioned in a news article. The improvements made improved the ranking of the events, but did not improve the ranking of the other concepts, such as places or actors.
Following, you can check the final presentations that the students gave to present their work:
A Concentric-based Approach to Represent News Topics in Tweets
Enya Nieland, June 21st 2017
The Relevance of Events in News Articles
Quentin van Langen, June 21st 2017