A large number of problems require the optimization of multiple
criteria. These crite- ria are often non-commensurate and sometimes
conflicting in nature making the task of optimization more difficult. In
such problems, the task of creating a combined opti- mization function
is often not easy. Moreover, the decision procedure can be affected by
the sensitivity of the solution space, and the trade-off is often
non-linear. In real life we traditionally handle such problems by
suggesting not one, but several non-dominated solutions. Finding a set
of non-dominated solutions is also useful in multistaged opti- mization
problems, where the solution of one stage of optimization is passed on
to the next stage. One classic example is that of circuit design, where
high-level synthesis, logic synthesis and layout synthesis comprise
important stages of optimization of the circuit. Passing a set of
non-dominated partial solutions from one stage to the next typically
ensures better global optimization. This book presents a new approach to
multi-criteria optimization based on heuristic search techniques.
Classical multicriteria optimization techniques rely on single criteria
optimization algorithms, and hence we are either required to optimize
one criterion at a time (under constraints on the others), or we are
asked for a single scalar combined optimization function. On the other
hand, the multiobjective search approach maps each optimization
criterion onto a distinct dimension of a vector valued cost structure.