%% $Id: abstract.tex,v 1.2 2005/01/14 06:07:24 gokhale Exp $
\begin{abstract}

{\em
Large-scale distributed real-time and embedded (DRE) systems incur
significant variability due to the need to execute on a wide range of
hardware, network, OS, and compiler platform configurations that both
enable and constrain their quality of service (QoS).  Middleware has
been the key enabling technology that addresses many of these sources
of variability. However, middleware also gives rise to another source
of variability arising from the numerous configuration and
customization (C\&C) options they provide to support product line
architectures. 

This paper provides two contributions to resolving the C\&C
variability. First, we describe a three dimensional model of middleware
C\&C variability management that middleware developers can use to
partition their middleware C\&C space. Second, we describe a
tool-based approach that DRE system developers can use to select the
right combination of C\&C options from the three-dimensional space
that can deliver the QoS requirements to DRE systems.
}
{\bf Keywords:} QoS-enabled Middleware, Variability and Tools.
\end{abstract}

