Browsing by Author "Ferrada, Sebastián"

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    Graph Querying or Similarity Search? Both!
    (2025) Calisto Barría, Vicente Esteban; Ferrada, Sebastián; Navarro, Gonzalo; Reutter de la Maza, Juan Lorenzo; Sánchez Abdala, Juan Pablo; Vrgoc, Domagoj
    Extracting information from knowledge graphs is a significant algorithmic challenge, especially when dealing with multimodal knowledge graphs that integrate images, text, and/or videos. While current graph management systems can efficiently evaluate graph queries, they struggle with multimedia data. To address this, systems rely on metadata, such as vector embeddings, for similarity search. While both graph pattern evaluation and similarity search work well independently, real-world applications often require their combination to retrieve media based on both the graph structure and specific similarity criteria.This paper studies the problem of querying multimodal knowledge graphs by combining graph patterns with similarity constraints. We formalize this as an extraction task where some nodes in the graph pattern are filtered by similarity, and then the results must be ordered by a similarity score. While a straightforward approach is to evaluate the graph pattern first and then sort by similarity, we introduce alternative algorithms that evaluate both tasks jointly, leveraging indices for efficient similarity computation. Our implementation employs an approximate version of these indices, and our experiments show that graph database systems can efficiently integrate semantic similarity constraints into their queries.
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    TelarKG: a knowledge graph of Chile's constitutional process
    (2024) Angles, Renzo; Calisto, Vicente; Díaz, Javiera; Ferrada, Sebastián; Hogan, Aidan; Pinto, Alexander; Reutter de la Maza, Juan Lorenzo; Rojas, Carlos; Rosales-Méndez, Henry; Sarmiento, Hernán; Toussaint, Etienne; Vrgoc Domagoj
    In this paper we present TelarKG, a knowledge graph (KG) that consolidates multiple sources of information regarding the Chilean Constitutional process, particularly about the work of the members of the Constitutional Convention. TelarKG contains a wide range of public data, such as the materials from the commissions and information about the members' interventions and votes. In addition, the KG has been enriched with online user-generated content including posts from social networks related to the constitutional process, and transcriptions from the YouTube videos of the plenary sessions. Among other features, TelarKG leverages the semantic similarity search capabilities of the MillenniumDB endpoint to compute text similarity among convention members' Twitter messages. Additionally, we employ Entity Linking techniques to identify references to members of the Convention and Parties within these messages. TelarKG constitutes one of the most comprehensive historical archives on a political event, enabling users to query and navigate through diverse aspects of Chile's constitutional process.