# Comments on "Propagation Modeling Over Irregular Terrain by the Improved Two-Way Parabolic Equation Method"

2014-07-01
Ozgun, Ozlem
Apaydin, Gokhan
Kuzuoğlu, Mustafa
Sevgi, Levent
The above paper [1] is about the two-way split-step parabolic equation method (2W-SSPE) over irregular terrain, and claims that they have developed the “improved” version of the 2W-SSPE approach that has been proposed and validated by us in literature [2]-[11]. The paper [1] claims to derive the 2W-PE directly from 2D Helmholtz equation. They do this by listing and explaining equations (1)-(9). The authors needed to state that this is quite different from the formulation given in Levy's book (reference [9] in [1]). Actually, factorization before or after does not mean anything; their equations (8) and (9) are exactly the same. As a result listing equations (1)-(9) does not mean derivation of the new two-way PE.
IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION

# Suggestions

 Comparison of dispersive and non-dispersive numarical long wave models and harbor agitation Özbay, Ali; Yalçıner, Ahmet Cevdet; Department of Civil Engineering (2012) In this study, the evolution of the numerical water wave models with the theoretical background and the governing equations are briefly discussed and a numerical model MIKE21 BW which can be applied to wave problems in nearshore zone is presented. The numerical model is based on the numerical solution of the Boussinesq type equations formulated on time domain. Nonlinearity and frequency dispersion is included in the model. In order to make comparison between the results of nonlinear shallow water equations ...
 Nonlinear Structural Coupling: Experimental Application Kalaycioglu, Taner; Özgüven, Hasan Nevzat (2014-02-06) In this work, the nonlinear structural modification/coupling technique proposed recently by the authors is applied to a test system in order to study the applicability of the method to real structures. The technique is based on calculating the frequency response functions of a modified system from those of the original system and the dynamic stiffness matrix of the nonlinear modifying part. The modification can also be in the form of coupling a nonlinear system to the original system. The test system used i...
 Quantitative measures of observability for stochastic systems Subaşı, Yüksel; Demirekler, Mübeccel; Department of Electrical and Electronics Engineering (2012) The observability measure based on the mutual information between the last state and the measurement sequence originally proposed by Mohler and Hwang (1988) is analyzed in detail and improved further for linear time invariant discrete-time Gaussian stochastic systems by extending the definition to the observability measure of a state sequence. By using the new observability measure it is shown that the unobservable states of the deterministic system have no effect on this measure and any observable part wit...
 Numerical solution of nonlinear reaction-diffusion and wave equations Meral, Gülnihal; Tezer, Münevver; Department of Mathematics (2009) In this thesis, the two-dimensional initial and boundary value problems (IBVPs) and the one-dimensional Cauchy problems defined by the nonlinear reaction- diffusion and wave equations are numerically solved. The dual reciprocity boundary element method (DRBEM) is used to discretize the IBVPs defined by single and system of nonlinear reaction-diffusion equations and nonlinear wave equation, spatially. The advantage of DRBEM for the exterior regions is made use of for the latter problem. The differential quad...
 Nonlinear guidance and control of leader-follower UAV formations Kumbasar, Sarper; Tekinalp, Ozan; Department of Aerospace Engineering (2015) In this thesis work, two nonlinear guidance methods are proposed to control the autonomous formation flight: State Dependent Riccati Equation method and Lyapunov function method. Leader-Follower formation scheme is chosen and a pair of fighter aircrafts are used in simulations. One of them is chosen as the leader and it carries out the commanded maneuvers. Other aircraft is the follower and it follows the leader keeping the prescribed formation structure. Both aircraft models are nonlinear. In the inner loo...
Citation Formats
O. Ozgun, G. Apaydin, M. Kuzuoğlu, and L. Sevgi, “Comments on “Propagation Modeling Over Irregular Terrain by the Improved Two-Way Parabolic Equation Method”,” IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION, pp. 3894–3894, 2014, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/40038.