This paper describes an improved model for multiple building diffraction modeling based on the uniform theory of diffraction (UTD). A well-known problem in conventional uniform theory of diffraction (CUTD) is multiple-edge transition zone diffraction. Here, higher order diffracted fields are used in order to improve the result; hence, we use higher order diffraction coefficients to improve a hy...

The problem is posed to develop Lyapunov theory for diierential systems described by high-order diierential algebraic equations. The questions are how to verify positivity along solutions of functionals of the system variables, to compute their derivative along solutions, and conclude (asymptotic) stability from there.