English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

The proliferation of RDF datasets has resulted in studies focusing onoptimizing SPARQL query processing. Most existing work focuses on basic graphpatterns (BGPs) and ignores other vital operators in SPARQL, such as UNION andOPTIONAL. SPARQL queries with these operators, which we abbreviate asSPARQL-UO, pose serious query plan generation challenges. In this paper, wepropose techniques for executing SPARQL-UO queries using BGP execution as abuilding block, based on a novel BGP-based Evaluation (BE)-Tree representationof query plans. On top of this, we propose a series of cost-driven BE-treetransformations to generate more efficient plans by reducing the search spaceand intermediate result sizes, and a candidate pruning technique that furtherenhances efficiency at query time. Experiments confirm that our methodoutperforms the state-of-the-art by orders of magnitude.

Efficient Execution of SPARQL Queries with OPTIONAL and UNION Expressions