  The problem of identifying intersections between two sets of d-dimensional
axis-parallel rectangles appears frequently in the context of agent-based
simulation studies. For this reason, the High Level Architecture (HLA)
specification -- a standard framework for interoperability among simulators --
includes a Data Distribution Management (DDM) service whose responsibility is
to report all intersections between a set of subscription and update regions.
The algorithms at the core of the DDM service are CPU-intensive, and could
greatly benefit from the large computing power of modern multi-core processors.
In this paper we propose two parallel solutions to the DDM problem that can
operate effectively on shared-memory multiprocessors. The first solution is
based on a data structure (the Interval Tree) that allows concurrent
computation of intersections between subscription and update regions. The
second solution is based on a novel parallel extension of the Sort Based
Matching algorithm, whose sequential version is considered among the most
efficient solutions to the DDM problem. Extensive experimental evaluation of
the proposed algorithms confirm their effectiveness on taking advantage of
multiple execution units in a shared-memory architecture.
