Stochastic Systems and Optimization : Proceedings of the 6th IFIP WG 7.1 Working Conference Warsaw Poland September 12 16 1988 The meeting intended to continue the traditional line of the foregoing conferences and to focus on topics of present research in the field of stochastic systems and optimization. Particular emphasis was placed on stochastic differential systems both finite and infinite dimensional filtering stochastic control asymptotic methods and periodic systems