Automatic face photo-sketch recognition has important applications for law enforcement.
Recent research has focused on transforming photos and sketches into the same modality …

Query languages for graph databases started to be investigated some 25 years ago. With
much current data, such as linked data on the Web and social network data, being graph …

RDF knowledge graphs are typically searched using triple-pattern queries. Often, triple-
pattern queries will return too many or too few results, making it difficult for users to find …

The LOD cloud offers a plethora of RDF data sources where users discover items of interest
by issuing SPARQL queries. A common query problem for users is to face with empty …

In this paper, we argue that query relaxation over RDF data is an important but largely
overlooked research topic: the Semantic Web standards allow for answering crisp queries …

Flexible querying techniques can enhance users' access to complex, heterogeneous
datasets in settings such as Linked Data, where the user may not always know how a query …

Recent years have witnessed the development of large knowledge bases (KBs). Due to the
lack of information about the content and schema semantics of KBs, users are often not able …

Approximate query answering relies on a similarity measure that evaluates the relevance,
for a given query, of a set of data extracted from the underlying database. In the context of …

Flexible querying techniques can be used to enhance users' access to heterogeneous data
sets, such as Linked Open Data. This paper extends SPARQL 1.1 with approximation and …

A query over RDF data is usually expressed in terms of matching between a graph
representing the target and a huge graph representing the source. Unfortunately, graph …