PUBLICATIONS

Discovering Diversified Paths in Knowledge Bases

Vast amounts of world knowledge is now accessible through Knowledge Graphs (KGs) in RDF format and can be queried using SPARQL. Yet, finding paths between nodes in such graphs is not part of the official SPARQL 1.1 standard; only the simpler functionality of checking reachability is supported, i.e., assessing whether two nodes are connected based on certain conditions formalized as property paths but without providing information on how they are actually connected. To close this gap of functionality, we propose JEDI, a Jena Extension for DIscovering diversified paths in knowledge bases. JEDI extends a popular SPARQL engine, Jena, with the ability to compute the paths connecting entities in a KG. JEDI shows the k most relevant results to the user where relevance is assessed as a trade-off between path length and diversification of the intermediate nodes in the path. Moreover, our solution is not limited to a single property path pattern but supports queries containing multiple property path patterns. While JEDI is able to work with any KG, for demonstration purposes some predefined KGs, such as YAGO and DBLP, are provided, as well as example queries. Attendees will be encouraged to interact with the JEDI system to try their own queries.

Top-K Diversification for Path Queries in Knowledge Graphs

To explore the relationships between entities in RDF graphs, property path queries were introduced in SPARQL 1.1. However, existing RDF engines return only reachability of the entities ignoring the intermediate nodes in the path. If the paths are output, they are too many, which makes it difficult for users to find the most relevant paths. To address this issue, we propose a generalized top- k ranking technique that balances the trade-off between relevance and diversity. We propose a shortest path based relevance scoring in combination with several path similarity measures for diversification. With preliminary experiments and examples, we show that our diversification strategies provide more informative paths compared to shortest path based ranking.

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