His main interest lies in mathematical system theory. His main contribution to the literature has been in formulation and characterization of the structural properties of singular systems and in parametrization of their orbits under the action of generalized feedback group. His recent work focuses on: (i)- classification of the orbits of weakly prime systems under the action of similarity transformations and application of this classification to the problems of pole assignment and stabilization by constant output feedback in linear systems, (ii)- robust Schur stability against structured perturbations, (iii)- H-infinity optimal control of a guided missile, and (iv)- partial disturbance rejection with an H-infinity norm bound.