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2012

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An Efficient Method For Computing Highly Oscillatory Physical Optics Integral, Y. M. Wu, Lijun Jiang, W. C. Chew Jan 2012

An Efficient Method For Computing Highly Oscillatory Physical Optics Integral, Y. M. Wu, Lijun Jiang, W. C. Chew

Electrical and Computer Engineering Faculty Research & Creative Works

In this work, we use the numerical steepest descent path (numerical SDP) method in complex analysis theory to calculate the highly oscillatory physical optics (PO) integral with quadratic phase and amplitude variations on the triangular patch. The Stokes' phenomenon will occur due to various asymptotic behaviors on different domains. The stationary phase point contributions are carefully studied by the numerical SDP method and complex analysis using contour deformation. Its result agrees very well with the leading terms of the traditional asymptotic expansion. Furthermore, the resonance points and vertex points contributions from the PO integral are also extracted. Compared with traditional …

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Hardware Emulation Of Wideband Correlated Multiple-Input Multiple-Output Fading Channels, Fei Ren, Yahong Rosa Zheng Jan 2012

Hardware Emulation Of Wideband Correlated Multiple-Input Multiple-Output Fading Channels, Fei Ren, Yahong Rosa Zheng

Electrical and Computer Engineering Faculty Research & Creative Works

A low-complexity hardware emulator is proposed for wideband, correlated, multiple-input multiple-output (MIMO) fading channels. the proposed emulator generates multiple discrete-time channel impulse responses (CIR) at the symbol rate and incorporates three types of correlation functions of the subchannels via Kronecker product: The spatial correlation between transmit or receive elements, temporal correlation due to Doppler shifts, and inter-tap correlation due to multipaths. the Kronecker product is implemented by a novel mixed parallel-serial (mixed P-S) matrix multiplication method to reduce memory storage and to meet the real-time requirement in high data-rate, large MIMO size, or long CIR systems. We present two practical …

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Optimization In Energy And Power Management For Renewable-Diesel Microgrids Using Dynamic Programming Algorithm, Tu A. Nguyen, Mariesa L. Crow Jan 2012

Optimization In Energy And Power Management For Renewable-Diesel Microgrids Using Dynamic Programming Algorithm, Tu A. Nguyen, Mariesa L. Crow

Electrical and Computer Engineering Faculty Research & Creative Works

This paper presents an optimization analysis for energy and power management in microgrids with renewable energy resources and diesel generators. Dynamic Programming (DP) algorithm and the simplex method have been used to minimize the total daily cost of the system and also maximize the total efficiency of the energy storage system during charge and discharge. the algorithm is validated on a hybrid system for military forward operating base camps that contain a PV array, wind generator, hydrogen-Based fuel cell, batteries and diesel generators. © 2012 IEEE.

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A Self-Tuning Optimal Controller For Affine Nonlinear Continuous-Time Systems With Unknown Internal Dynamics, Travis Dierks, Sarangapani Jagannathan Jan 2012

A Self-Tuning Optimal Controller For Affine Nonlinear Continuous-Time Systems With Unknown Internal Dynamics, Travis Dierks, Sarangapani Jagannathan

Electrical and Computer Engineering Faculty Research & Creative Works

This paper presents a novel neural network (NN) - based self-tuning controller for the optimal regulation of affine nonlinear continuous-time systems. Knowledge of the internal system dynamics is not required whereas the control coefficient matrix is considered to be available. the proposed nonlinear optimal regulator tunes itself in order to simultaneously learn the optimal control input, optimal cost function, and the system internal dynamics using a single NN. a novel NN weight tuning algorithm is derived which ensures the internal system dynamics are learned while simultaneously minimizing a predefined cost function. an initial stabilizing controller is not required. Lyapunov methods …

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Cross-Layer Design Of Energy Efficient Coded Arq Systems, Gang Wang, Jingxian Wu, Yahong Zheng Jan 2012

Cross-Layer Design Of Energy Efficient Coded Arq Systems, Gang Wang, Jingxian Wu, Yahong Zheng

Electrical and Computer Engineering Faculty Research & Creative Works

The energy efficient design of coded automatic-repeat-request (ARQ) systems is studied in this paper. the optimization aims to minimize the energy required for the successfully delivery of one information bit from a transmitter to a receiver. the design is performed by incorporating a wide range of practical system parameters and metrics, such as hardware power consumption, modulation, channel coding, and frame error rate (FER) in the physical layer, and frame length and protocol overhead in the media access control layer. a new log-domain threshold approximation method is proposed to analytically quantify the impacts of the various system parameters on the …

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Optimal Adaptive Control Of Nonlinear Continuous-Time Systems In Strict Feedback Form With Unknown Internal Dynamics, H. Zargarzadeh, T. Dierks, S. Jagannathan Jan 2012

Optimal Adaptive Control Of Nonlinear Continuous-Time Systems In Strict Feedback Form With Unknown Internal Dynamics, H. Zargarzadeh, T. Dierks, S. Jagannathan

Electrical and Computer Engineering Faculty Research & Creative Works

A novel approach is proposed for multi-input multi-output (MIMO) optimal adaptive control of nonlinear continuous-time systems in strict feedback form with uncertain internal dynamics. First, it is shown that the optimal adaptive tracking problem of strict feedback systems can be reduced to an optimal regulation problem of affine nonlinear continuous-time systems expressed as a function of tracking error by designing a properly chosen adaptive feedforward control input. Then, an optimal adaptive feedback scheme is introduced for the affine system to estimate the solution of the Hamilton-Jacobi-Bellman (HJB) equation online which becomes the optimal feedback control input for the closed-loop system. …

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Optimal Adaptive Controller Scheme For Uncertain Quantized Linear Discrete-Time System, Qiming Zhao, Hao Xu, S. Jagannathan Jan 2012

Optimal Adaptive Controller Scheme For Uncertain Quantized Linear Discrete-Time System, Qiming Zhao, Hao Xu, S. Jagannathan

Electrical and Computer Engineering Faculty Research & Creative Works

In this paper, the Bellman equation is used to solve the optimal adaptive control of quantized linear discrete-time system with unknown dynamics. to mitigate the effect of the quantization errors, the dynamics of the quantization error bound and an update law for tuning the range of the dynamic quantizer are derived. Subsequently, by using adaptive dynamic programming technique, the infinite horizon optimal regulation problem of the uncertain quantized linear discrete-time system is solved in a forward-in-time manner without using value and/or policy iterations. the asymptotic stability of the closed-loop system is verified by standard Lyapunov stability approach in the presence …

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State And Output Feedback-Based Adaptive Optimal Control Of Nonlinear Continuous-Time Systems In Strict Feedback Form, H. Zargarzadeh, T. Dierks, S. Jagannathan Jan 2012

State And Output Feedback-Based Adaptive Optimal Control Of Nonlinear Continuous-Time Systems In Strict Feedback Form, H. Zargarzadeh, T. Dierks, S. Jagannathan

Electrical and Computer Engineering Faculty Research & Creative Works

This paper focuses on neural network (NN) based adaptive optimal control of nonlinear continuous-time systems in strict feedback form with known dynamics. a single NN is utilized to learn the infinite horizon cost function which is the solution to the Hamilton-Jacobi-Bellman (HJB) equation in continuous-time. the corresponding optimal control input that minimizes the HJB equation is calculated in a forward-in-time manner without using value and policy iterations. First, the optimal control problem is solved in a generic multi-input and multi output (MIMO) nonlinear system in strict feedback form with a state feedback approach. Then, the approach is extended to single …

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A Modified Fixed Sphere Decoding Algorithm For Under-Determined Mimo Systems, Chen Qian, Jingxian Wu, Yahong Rosa Zheng, Zhaocheng Wang Jan 2012

A Modified Fixed Sphere Decoding Algorithm For Under-Determined Mimo Systems, Chen Qian, Jingxian Wu, Yahong Rosa Zheng, Zhaocheng Wang

Electrical and Computer Engineering Faculty Research & Creative Works

A modified FSD algorithm is proposed for under-determined (UD) multiple-input multiple-output (MIMO) systems with N transmit antennas and M < N receive antennas. This paper focuses on the low-complexity detection of coded UD-MIMO systems with iterative turbo detection, where a soft-input soft-output (SISO) MIMO detector exchanges soft information with a SISO decoder. in the first iteration, a modified fixed complexity sphere decoding (FSD) method is developed by utilizing the structure of a UD-MIMO system. the modified FSD employs a new detection ordering scheme that has a lower complexity but a better performance compared to the conventional ordering scheme. from the second iteration and beyond, the MIMO detector is implemented with a generalized serial interference cancelation (GSIC) scheme and a block decision feedback equalizer (BDFE) to further reduce the complexity. Simulation results show that the newly proposed FSD-GSIC-BDFE structure can achieve significant performance gains over existing schemes, especially for systems with high level modulations. © 2012 IEEE.

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Worst-Case Estimation For Data-Dependent Timing Jitter And Amplitude Noise In High-Speed Differential Link, Wei Yao, Yiyu Shi, Lei He, Sudhakar Pamarti Jan 2012

Worst-Case Estimation For Data-Dependent Timing Jitter And Amplitude Noise In High-Speed Differential Link, Wei Yao, Yiyu Shi, Lei He, Sudhakar Pamarti

Electrical and Computer Engineering Faculty Research & Creative Works

Differential signaling has been widely used in high-speed interconnects. Signal integrity issues, such as inter-symbol interference (ISI) and crosstalk between the differential pair, however, still cause significant timing jitter and amplitude noise and heavily limit the performance of the differential link. the pre-emphasis filter is commonly used to reduce ISI but may potentially change the crosstalk behavior. in this paper, we first propose formula-Based jitter and noise models considering the combined effect of ISI, crosstalk, and pre-emphasis filter. with the same set of input patterns, experiment shows our models achieve within 5% difference compared with SPICE simulation. by utilizing these …

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