As an important component in parallel software engineering, 
software integration plays an indispensable role in building
large-scale, multi-disciplinary parallel and distributed 
applications on high-performance
computing systems. 
In this study we propose a software integration framework that is based
on a dataflow programming paradigm and execution model for general-purpose 
HPDC applications. Advantages of this dataflow-based model
are investigated and demonstrated.
We study applications of this model in several specific, yet
typical, areas that have general needs for parallel software integration and
are well suited to this dataflow model. Drawing from extensive software and system 
integration case studies in those areas,
we present the general requirements for a software integration framework
in an HPDC application. These areas include:

\begin{enumerate}
\item
integration of multiple parallel programming paradigms in a single
unified environment;

\item
integration of interactive data visualization and parallel 
computations on a hetergeneous distributed environment;

\item
integration of networking navigation and parallel relational database
management system (RDBMS); and 

\item
integration of World Wide Web computing
and information processing. 
\end{enumerate}

By viewing different parallel programming paradigms as an essentially 
heterogeneous approach in mapping ``real-world'' problems to parallel
systems, we discuss methodologies in integrating multiple programming
models on a massively parallel system.
Three applications in earth science, financial modeling,
and computational electromagnetics 
are studied
to demonstrate the integration of data-parallel
and message-passing modules in the proposed multi-paradigm programming
environment.

We develop interactive visualization systems 
on heterogeneous parallel and distributed computers.  
Using the dataflow model of
an AVS testbed in two case studies in
financial
modeling and computational electromagnetics applications,
we demonstrate
a modular approach
to couple parallel simulation
modules into an interactive remote visualization environment.

Viewing the client-server model as an essentially 
restricted dataflow model, 
we describe the concept of integrating distributed computing
in  a World Wide Web (WWW) environment
for data-intensive Internet applications.
We examine approaches in integrating parallel
relational databases and a Web-based networking navigation interface.
Realization of the proposed dataflow integration model in Java and WWW
is also described.