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2014

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Cosimulation Of Electromagnetics-Circuit Systems Exploiting Dgtd And Mna, Ping Li, Li (Lijun) Jun Jiang, Hakan Bagci Jan 2014

Cosimulation Of Electromagnetics-Circuit Systems Exploiting Dgtd And Mna, Ping Li, Li (Lijun) Jun Jiang, Hakan Bagci

Electrical and Computer Engineering Faculty Research & Creative Works

A hybrid electromagnetics (EM)-circuit simulator exploiting the discontinuous Galerkin time domain (DGTD) method and the modified nodal analysis (MNA) algorithm is developed for analyzing hybrid distributive and nonlinear multiport lumped circuit systems. The computational domain is split into two subsystems. One is the EM subsystem that is analyzed by DGTD, while the other is the circuit subsystem that is solved by the MNA method. The coupling between the EM and circuit subsystems is enforced at the lumped port where related field and circuit unknowns are coupled via the use of numerical flux, port voltages, and current sources. Since the spatial …

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A Calderón Preconditioner For The Electric Field Integral Equation With Layered Medium Green's Function, Yongpin P. Chen, Sheng Sun, Lijun Jiang, Weng Cho Chew Jan 2014

A Calderón Preconditioner For The Electric Field Integral Equation With Layered Medium Green's Function, Yongpin P. Chen, Sheng Sun, Lijun Jiang, Weng Cho Chew

Electrical and Computer Engineering Faculty Research & Creative Works

A Calderón preconditioner is developed for the analysis of electromagnetic scattering of perfect electrically conducting (PEC) objects embedded in a layered medium. The electric field integral equation (EFIE) is formulated with the kernel of layered medium Green's function to account for the effects from the multilayered background. The Calderón projector is derived based on the general source-field relationship and the extinction theorem for inhomogeneous environment in electromagnetic theory. The Calderón identities can be naturally deduced based on this projector, which is then leveraged to precondition the EFIE with layered kernel. An alternative implementation is then proposed to make the implementation …

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Model Order Reduction For Quantum Transport Simulation Of Band-To-Band Tunneling Devices, Jun Z. Huang, Lining Zhang, Weng Cho Chew, Chi Yung Yam, Li (Lijun) Jun Jiang, Guan Hua Chen, Mansun Chan Jan 2014

Model Order Reduction For Quantum Transport Simulation Of Band-To-Band Tunneling Devices, Jun Z. Huang, Lining Zhang, Weng Cho Chew, Chi Yung Yam, Li (Lijun) Jun Jiang, Guan Hua Chen, Mansun Chan

Electrical and Computer Engineering Faculty Research & Creative Works

Simulations of nanoelectronic devices with nonequilibrium Greens function are computationally very intensive, in particular, when combined with multiband approaches, such as the k p methods. To reduce the cost and make the simulation of realistic devices tractable, we have developed a model order reduction method for the simulation of hole transport in silicon nanowires using three- and six-band k p models. It is shown in this paper that, with a spurious band elimination process, the method can be readily extended to the eight-band case that enables us to simulate band-to-band tunneling devices. The method is demonstrated via constructing reduced models …

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Approximate Dynamic Programming, Local Or Global Optimal Solution?, Ali Heydari, S. N. Balakrishnan Jan 2014

Approximate Dynamic Programming, Local Or Global Optimal Solution?, Ali Heydari, S. N. Balakrishnan

Mechanical and Aerospace Engineering Faculty Research & Creative Works

The problem of global optimality analysis of approximate dynamic programming-based solutions is investigated in this study. Sufficient conditions for global optimality are obtained without requiring the state penalizing terms in the cost function or the functions representing the dynamics to be convex functions. Afterwards, the theoretical results are confirmed through a qualitative analysis of an example problem. © 2014 American Automatic Control Council.

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Optimal Switching Of Nonlinear Systems With Free Mode Sequence, Ali Heydari, S. N. Balakrishnan Jan 2014

Optimal Switching Of Nonlinear Systems With Free Mode Sequence, Ali Heydari, S. N. Balakrishnan

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Approximate dynamic programming is utilized in this study to develop solutions for optimal switching problems. The order of the active subsystems and the number of switches are free, and an online solution is developed that produces optimal performance. Motivated by the development in the adaptive critic's literature, the proposed method uses a critic and as many actors as the number of subsystems in order to conduct optimal scheduling in real-time based on the instantaneous states of the system. It is observed that once the neural networks are trained offline based on the proposed algorithm, they provide solutions for a range …

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Resilient Networked Multiagent Systems: A Distributed Adaptive Control Approachy, Gerardo De La Torre, Tansel Yucelen, John Daniel Peterson Jan 2014

Resilient Networked Multiagent Systems: A Distributed Adaptive Control Approachy, Gerardo De La Torre, Tansel Yucelen, John Daniel Peterson

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Control algorithms of networked multiagent systems are generally computed distributivity without having a centralized entity monitoring the activity of agents; and therefore, adverse events such as attacks to the communication network and/or failure of agent-wise components can easily result in system instability and prohibit the accomplishment of system-level objectives. This paper studies resilient coordination of networked multiagent systems in the presence of misbehaving agents, i.e., agents that are subject to such adverse events. In particular, we consider a class of adverse conditions consisting of exogenous disturbances and interagent uncertainties and present a distributed adaptive control architecture to retrieve the nominal …

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