Databases 2
☆ Condensed Representation of RDF and its Application on Graph Versioning
The study of the evolving phenomena in a domain helps to understand the
relationships between entities at different points in time and predict future
trends. These phenomena, often complex, can be represented using knowledge
graphs, which have the capability to model heterogeneous data from multiple
sources. Nowadays, a considerable amount of sources delivering periodic updates
to knowledge graphs in various domains is openly available. The evolution of
data is of interest to knowledge graph management systems, and therefore it is
crucial to organize these constantly evolving data to make them easily
accessible and exploitable for analyzes. In this article, we will present and
formalize the condensed representation of these evolving graphs.
comment: 20 pages, 3 figures
♻ ☆ Localized RETE for Incremental Graph Queries with Nested Graph Conditions
The growing size of graph-based modeling artifacts in model-driven
engineering calls for techniques that enable efficient execution of graph
queries. Incremental approaches based on the RETE algorithm provide an adequate
solution in many scenarios, but are generally designed to search for query
results over the entire graph. However, in certain situations, a user may only
be interested in query results for a subgraph, for instance when a developer is
working on a large model of which only a part is loaded into their workspace.
In this case, the global execution semantics can result in significant
computational overhead.
To mitigate the outlined shortcoming, in this article we propose an extension
of the RETE approach that enables local, yet fully incremental execution of
graph queries, while still guaranteeing completeness of results with respect to
the relevant subgraph.
We empirically evaluate the presented approach via experiments inspired by a
scenario from software development and with queries and data from an
independent social network benchmark. The experimental results indicate that
the proposed technique can significantly improve performance regarding memory
consumption and execution time in favorable cases, but may incur a noticeable
overhead in unfavorable cases.
comment: arXiv admin note: substantial text overlap with arXiv:2405.01145