By Sara Abdollahi, PhD student, L3S Research Center
The world is frequently experiencing events such as terrorist attacks, Brexit, and the migrant crisis, that has resulted in a vast amount of event-centric information on the web. Researchers, particularly digital humanities researchers and social scientists who analyse the significant events that influence and shape our societies, can benefit from web archives that reflect the perception of events as they happened at the time.
The Research challenge
Web archiving services provide a preserved state of the web that facilitates its study in the future. The ever-growing structure of web archives is one of the main challenges in accessing information for specific research. It is often difficult or even impossible for researchers to find their required documents. Typically, web archives offer interfaces for the users to access the information they need through keyword search. Researchers can then type the name of the event they are interested in and retrieve a list of web documents containing the text's keyword. The returned results are often overwhelming due to their quantity, potential redundancy, and irrelevance, needing an additional intensive cleaning phase to get more related web documents.
The UK Web Archive (UKWA) as well as some other web archives, offer manually collected event-centric collections to solve this issue, which can be considerably time-consuming to create. More importantly, these collections might not cover all necessary information related to a specific event.
A Potential Solution
To address the mentioned challenge, I propose automatically building event collections from web archives using knowledge graphs. Knowledge graphs such as Wikidata and DBpedia are collections of interlinked real-world entities and concepts.
In this research, I utilise the EventKG knowledge graph which provides structured information about events, their characteristics, and relationships (e.g., sub-events) and can thus be used as a resource for extending and diversifying the search space when building event collections.
Take the Arab Spring as an example; Tunisian Revolution, Bahraini protests of 2011, and 2011 Yemeni revolution are three sub-events of it. The figure below demonstrates an example of using EventKG to create event collections for Arab Spring.
By utilising sub-events to expand the initial user query, a more diverse initial set of documents can be retrieved. This process leads to increased precision and coverage of the final event collection. Traditional methods might miss related documents to sub-events if there is no mention of the main event in those documents. To advance such methods, I demonstrate the impact of event-centric features and relations from a knowledge graph on building event collections.
Sara is giving a presentation of this project at IIPC Web Archive Conference 2022 (session 15) - Register for free.