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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
problems.
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