  The synthesis problem of a cyber-physical system (CPS) is to find an input
signal under which the system's behavior satisfies a given specification. Our
setting is that the specification is a formula of signal temporal logic, and
furthermore, that the specification is a conjunction of different and often
conflicting requirements. Conjunctive specifications are often challenging for
optimization-based falsification -- an established method for CPS analysis that
can also be used for synthesis -- since the usual framework (especially how its
robust semantics handles Boolean connectives) is not suited for finding
delicate trade-offs between different requirements. Our proposed method
consists of the combination of optimization-based falsification and constrained
optimization. Specifically, we show that the state-of-the-art multiple
constraint ranking method can be combined with falsification powered by CMA-ES
optimization; its performance advantage is demonstrated in experiments.
