DSA Volume 1 Issue 4 December 2010 - Defence Science and ...

A better analytical tool for
‘hit or miss’ situations
DSTO Fellowship Program
research has delivered
a more efficient way to
study complex system
operations, greatly
benefiting investigations
in areas such as guided
missile target tracking.
Systems analysts and engineers attempting to
predict the outcomes of complex systems with
highly variable inputs often use a statisticalbased
simulation known as Monte Carlo for
the purpose. This approach produces a set
of probabilities of certain events happening
for a particular set of input variable ranges
by running hundreds of simulations.
For complex systems, in which input variables
interact in linear mathematical ways, another
method of performance analysis is being
explored by DSTO’s Dr Domenic Bucco. Known
as adjoint simulation method, it provides a
quicker and more economic means of study.
“Adjoint theory has its origins in work done
several hundred years ago by mathematicians
to solve certain kinds of differential
equations,” explains Dr Bucco. “This has
since been developed into a means for
performance analysis of linear time varying
systems, referred to as LTVs in short.
“Given an LTV system with ‘n’ inputs and ‘m’
outputs, the adjoint method can generally be
used to determine the sensitivity of any of
the outputs at a fixed time to each of the ‘n’
inputs. The technique provides analysts with
a simple but powerful alternative to the Monte
Carlo method for systems where a linearised
form of modelling approach is acceptable.”
The method has been successfully applied
to the study of guided missile homing loops
as well as to the preliminary and conceptual
definition stages of many new missile programs.
Dr Domenic Bucco explaining the adjoint method modelling approach to a colleague.
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