Ph D abstract - Morgan Ericsson

Composition and Optimization

A recent trend in software engineering is to delay design decisions. One motiva-
tion is that requirements or properties of the application and environment are not
known until later in the design and development process. This continues to hold
for design decisions in a high-performance context where e.g., the number of
processors is assigned late to applications and their components.

In this thesis we present three case studies, ranging from Web Services and Grid
computing to library design. In each of these case studies we study how perfor-
mance requirements, and both properties of the application and the environment
determine when design decisions can be made. We found that in many scenarios,
design decisions have to be delayed, sometimes even until execution time.

Based on our findings, we introduce context-aware composition, a composition
technique that allows the designer to specify a set of variant implementations, a
set of properties and goal criteria. The context-aware composition then composes
the variants into a best-fit application according to the goal criteria as well as ap-
plication and environmental properties. The composition will happen automati-
cally at the earliest possible time i.e., when enough information is available, ei-
ther off-line or on-line. By using context-aware composition,
developers can focus on the functional aspects of the application, and let the
composition technique decide the delayed optimization decisions.

We show that each of the cases studies is a special case of the context-aware
composition. This makes context-aware composition a solution to the three pro-
blems solved in the case studies as well as a possible solution to other similar



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Last modified on August 2008 by Anne Moe