ShEx (Shape Expressions) is a language for expressing constraints on RDF graphs. In this work we optimize the evaluation of conjunctive SPARQL queries, on RDF graphs, by taking advantage of ShEx constraints. Our optimization is based on computing and assigning ranks to query triple patterns, dictating their order of execution. We first define a set of well formed ShEx schemas, that possess interesting characteristics for SPARQL query optimization. We then define our optimization method by exploiting information extracted from a ShEx schema. We finally report on evaluation results performed showing the advantages of applying our optimization on the top of an existing state-of-the-art query evaluation system.
ShEx (Shape Expressions) is a language for expressing constraints on RDF graphs. We consider the problem of SPARQL query containment in the presence of ShEx constraints. We first propose a sound and complete procedure for the problem of containment with ShEx, considering several SPARQL fragments. Particularly our procedure considers OPTIONAL query patterns, that turns out to be an important fragment to be studied with schemas. We then show the complexity bounds of our problem with respect to the fragments considered. To the best of our knowledge, this is the first work addressing SPARQL query containment in the presence of ShEx constraints.
Language games are forms of language that systematically manipulate normal spoken words in order to make them illegible by others. These languages highlight a good number of phonological processes employed by speakers of language games to distort source words. Among these processes are epenthesis, gemination, consonant insertion, and metathesis. The current study proceeds to verify the hypotheses that these processes are already present in normal language and that these processes take place in a systematic manner yielding uniform patterns. The collected data and the literature include a wide range of database out of which instances of distortional pieces of speech can be drawn and described. The conclusion reached out in this study is that these processes provide some insight into the structure of the source languages or dialects on which the language games are based.
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