Optimising and Executing DAPLEX Queries using Prolog

Executing Trace Specifications Using Prolog

Executing In-network Queries Using SNEE

The SNEE query optimizer enables users to characterize data requests against wireless sensor networks (WSNs), using a declarative query language called SNEEql (SNEE for SensorNEtworkEngine, described in [GBG11], and publicly available at http://code.google.com/p/snee). Queries are compiled into imperative query execution plans, which are translated into executable nesC source code. In this pape...

Executing Nested Queries

Optimization of nested queries, in particular finding equivalent “flattened” queries for queries that employ the SQL sub-query construct, has been researched extensively. In contrast, with the exception of nested loops join, execution of nested plans has found little interest. Nested execution plans may result from a failure to flatten nested SQL expressions but just as likely are created by a ...

Syntactic Tree Queries in Prolog

In this paper, we argue for and demonstrate the use of Prolog as a tool to query annotated corpora. We present a case study based on the German TüBa-D/Z Treebank to show that flexible and efficient corpus querying can be started with a minimal amount of effort. We end this paper with a brief discussion of performance, that suggests that the approach is both fast enough and scalable.

Optimising Web Queries Using Document Type De nitions

A document type deenition (DTD) D deenes the structure of elements permitted in any web document valid with respect to D. From a given DTD D we show how to derive a number of simple structural constraints which are implied by D. Using a relational abstraction of web databases, we consider a class of conjunctive queries which retrieve elements from web documents stored in a database D. For simpl...