DyOS is a software tool for the solution of dynamic optimization problems. This problem class includes the optimization of chemical plant design and operation, and a large variety of related applications.

A large class of dynamic optimization problems involve models given by differential-algebraic equations.
DyOS allows the model to be accessed via a so-called Equation Set Object (ESO) interface, a standard developed in the Cape-Open project. The commercial modeling and simulation package gPROMS, for example, can be used as a model server for DyOS. But also the free model server ACSAMMM can be used (using Modelica as model language).
DyOS features state-of-the-art numerical solution methods, among them an automatic adaptation of the control profile discretization. DyOS has successfully been used to solve multi-stage problems, mixed integer dynamics optimization problems, dynamic parameter and input estimations, and optimal experimental design problems.

DyOS has been developed at AVT.PT and is still under continuous development at AVT.SVT. It has been released by AVT.PT under the GNU General Public License GPL v3.0.
The sources can be found here.