A new technique, the steepest descent-fast multipole method (SDFMM), is developed to efficiently analyze scattering from perfectly conducting random rough surfaces. Unlike other prevailing methods, this algorithm has ...
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A new technique, the steepest descent-fast multipole method (SDFMM), is developed to efficiently analyze scattering from perfectly conducting random rough surfaces. Unlike other prevailing methods, this algorithm has linear computational complexity and memory requirements, making it a suitable candidate for analyzing scattering from large rough surfaces as well as for carrying out Monte Carlo simulations. The method exploits the quasiplanar nature of rough surfaces to efficiently evaluate the dyadic Green's function for multiple source and observation points. This is achieved through a combination of a Sommerfeld steepest descent integral and a multilevel fast multipole-like algorithm based on inhomogeneous plane wave expansions. The fast evaluation of the dyadic Green's function dramatically speeds up the iterative solution of the integral equation for rough surface scattering, Several numerical examples are presented to demonstrate the efficacy and accuracy of the method in analyzing scattering from extremely large finite rough surfaces.
A partially asynchronous co-state prediction algorithm for the solution of the optimal control problem of linear large-scale systems is presented. A detailed study of the convergence behaviour of the proposed algorith...
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A partially asynchronous co-state prediction algorithm for the solution of the optimal control problem of linear large-scale systems is presented. A detailed study of the convergence behaviour of the proposed algorithm is given, taking into consideration the effect of communication delay among the processors forming the overall system. The results of applying the new algorithm to simulation examples are presented and compared with those obtained using the well-known synchronous algorithm.
A multilevel algorithm is presented for evaluating fields generated by given distributions of electric current. The algorithm can be used to accelerate the solution of scattering problems using the method of moments a...
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A multilevel algorithm is presented for evaluating fields generated by given distributions of electric current. The algorithm can be used to accelerate the solution of scattering problems using the method of moments and/or boundary element methods. The algorithm exploits the limited number of degrees of freedom that characterize a field observed over a domain that is well separated from a source domain. Both the memory requirements and the computational complexity of the algorithm are O(N(s) log(N(s)), where N(s) is the common number of sources and observation points. The multilevel algorithm can easily be incorporated into existing method-of-moments (MoM) programs. A simple physical interpretation of the algorithm is provided. (C) 1994 John Wiley & Sons, Inc.
A fast algorithm for compact fixed-point problems with nonsmooth nonlinearities is designed and analyzed. The algorithm is a combination of an extension of the Atkinson-Brakhage-Nystrom algorithm for smooth problems a...
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A fast algorithm for compact fixed-point problems with nonsmooth nonlinearities is designed and analyzed. The algorithm is a combination of an extension of the Atkinson-Brakhage-Nystrom algorithm for smooth problems and a generalization of work by Yamamoto and Chen for nonsmooth problems. A critical structural hypothesis in the general theory is explicitly verified in the context of problems that can be expressed as integral equations with certain types of nonsmoothness. The work is motivated by problems in combat modeling. In particular, we consider the solution of an optimality system that arises in control of competitive systems.
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