  In this paper, a space-time discontinuous Galerkin finite element method for
distributed optimal control problems governed by unsteady
diffusion-convection-reaction equations with control constraints is studied.
Time discretization is performed by discontinuous Galerkin method with
piecewise constant and linear polynomials, while symmetric interior penalty
Galerkin with upwinding is used for space discretization. The numerical results
presented confirm the theoretically observed convergence rates.
