1. School of Mechanical and Aerospace Engineering, Oklahoma State University, Stillwater, Oklahoma 74078, USA
2. Department of Engineering Cybernetics, Norwegian University of Science and Technology, N-7465 Trondheim, Norway
3. Department of Mathematics and Cybernetics, SINTEF Digital, 7034 Trondheim, Norway
4. Department of Mathematics, Virginia Tech, Blacksburg, Virginia 24061, USA