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Electrical and Computer Engineering Faculty Research & Creative Works

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Full-Text Articles in Engineering

Critical Path Monitor Enabled Dynamic Voltage Scaling For Graceful Degradation In Sub-Threshold Designs, Yu Guang Chen, Tao Wang, Kuan Yu Lai, Wan Yu Wen, Yiyu Shi Jan 2014

Critical Path Monitor Enabled Dynamic Voltage Scaling For Graceful Degradation In Sub-Threshold Designs, Yu Guang Chen, Tao Wang, Kuan Yu Lai, Wan Yu Wen, Yiyu Shi

Electrical and Computer Engineering Faculty Research & Creative Works

Sub-threshold designs play an important role in energy constrained applications. In those designs, path delays depend exponentially on threshold voltage/temperature. As such, dynamic configurations at runtime are desired for best trade-off between operating power and performance. Unfortunately, most existing works only consider either process or temperature variations but not both, resulting in sub-optimal configurations or even functional failures. Moreover, little study has been performed on the graceful degradation of sub-threshold designs, which is important in the presence of drastic delay variations. Towards this, we present a novel critical path monitor based dynamic voltage scaling scheme. Considering both process and temperature …

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An Accurate Frame Error Rate Approximation Of Coded Diversity Systems With Non-Identical Diversity Branches, Gang Wang, Jingxian Wu, Yahong Rosa Zheng Jan 2014

An Accurate Frame Error Rate Approximation Of Coded Diversity Systems With Non-Identical Diversity Branches, Gang Wang, Jingxian Wu, Yahong Rosa Zheng

Electrical and Computer Engineering Faculty Research & Creative Works

This paper presents an accurate approximation of the frame error rate (FER) of coded wireless communication systems with receiver diversity, such as single-input multiple-output (SIMO) systems with maximum ratio combining (MRC) or hybrid automatic repeat request (HARQ) systems with Chase combining. The signals at different diversity branches experience independent but non-identically distributed Rayleigh fading. The FER approximation is obtained with a threshold-based method. Specifically, the threshold value, which is critical to the FER approximation accuracy, is modeled as a linear function of the frame length in the log-domain, with the slope and intercept of the linear function determined by the …

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Fixed Final-Time Near Optimal Regulation Of Nonlinear Discrete-Time Systems In Affine Form Using Output Feedback, Qiming Zhao, Hao Xu, S. Jagannathan Jan 2014

Fixed Final-Time Near Optimal Regulation Of Nonlinear Discrete-Time Systems In Affine Form Using Output Feedback, Qiming Zhao, Hao Xu, S. Jagannathan

Electrical and Computer Engineering Faculty Research & Creative Works

In this paper, the fixed final-time near optimal output regulation of affine nonlinear discrete-time systems with unknown system dynamics is considered. First, a neural network (NN)-based observer is proposed to reconstruct both the system state vector and control coefficient matrix. Next, actor-critic structure is utilized to approximate the time-varying solution of the Hamilton-Jacobi-Bellman (HJB) equation or value function. To satisfy the terminal constraint, a new error term is defined and incorporated in the NN update law so that the terminal constraint error is also minimized over time. A NN with constant weights and time-dependent activation function is employed to approximate …

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Converting An Old Machines Lab Into A Functioning Power Network With A Microgrid For Education, Md Rasheduzzaman, Badrul H. Chowdhury, Shyam Bhaskara Jan 2014

Converting An Old Machines Lab Into A Functioning Power Network With A Microgrid For Education, Md Rasheduzzaman, Badrul H. Chowdhury, Shyam Bhaskara

Electrical and Computer Engineering Faculty Research & Creative Works

As colleges prepare or revise their power engineering courses to include discussions on the smart grid, the microgrid, distributed energy sources and renewable energy resources, the need for new material suitable for inclusion in a typical 4-year undergraduate engineering course has never been more obvious. Toward this effort, an old machines lab was remodeled and converted into a small power network that can be operated in both grid-connected and grid-islanded microgrid modes. The intent of this paper is to devise laboratory experiments to supplement a course in conventional power systems analysis at the undergraduate level. During the remodeling process, two …

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Optimization Of Transmission Conditions In Waveform Relaxation Techniques For Rc Circuits, Mohammad D. Al-Khaleel, Martin J. Gander, Albert E. Ruehli Jan 2014

Optimization Of Transmission Conditions In Waveform Relaxation Techniques For Rc Circuits, Mohammad D. Al-Khaleel, Martin J. Gander, Albert E. Ruehli

Electrical and Computer Engineering Faculty Research & Creative Works

Waveform relaxation techniques have become increasingly important with the wide availability of parallel computers with a large number of processors. A limiting factor for classical waveform relaxation, however, is the convergence speed for an important class of problems, especially if long time windows are considered. In contrast, the optimized waveform relaxation algorithm discussed in this paper is well suited to address this problem. Today several numerical analyses have shown that optimized waveform relaxation algorithms can overcome slow convergence over long time windows. However, the optimized waveform relaxation techniques require the determination of optimized parameters. In this paper, we present a …

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Adaptive Neural Network-Based Optimal Control Of Nonlinear Continuous-Time Systems In Strict-Feedback Form, H. Zargarzadeh, T. Dierks, S. Jagannathan Jan 2014

Adaptive Neural Network-Based 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 optimal control of nonlinear continuous-time systems in strict-feedback form when the system dynamics are known by using an adaptive backstepping approach. A single NN-based adaptive approach is designed to learn the solution of the infinite horizon continuous-time Hamilton-Jacobi-Bellman (HJB) equation while 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 for a generic multi-input and multi-output nonlinear system with a state feedback approach. Then the approach is extended to a single-input and …

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Efficient Implementation Of Iterative Multi-Input-Multi-Output Orthogonal Frequency-Division Multiplexing Receiver Using Minimum-Mean-Square Error Interference Cancellation, Bing Han, Zengli Yang, Yahong Rosa Zheng Jan 2014

Efficient Implementation Of Iterative Multi-Input-Multi-Output Orthogonal Frequency-Division Multiplexing Receiver Using Minimum-Mean-Square Error Interference Cancellation, Bing Han, Zengli Yang, Yahong Rosa Zheng

Electrical and Computer Engineering Faculty Research & Creative Works

An efficient hardware implementation scheme is proposed for iterative multi-input-multi-output orthogonal frequency division multiplexing receiver which includes an MMSE-IC (minimum-mean-square error interference cancellation) detector, a channel estimator, a low-density parity-check (LDPC) decoder and other supporting modules. The proposed implementation uses the QR decomposition (QRD) of the complex-valued matrices with four coordinate rotation digital computer (CORDIC) cores and a back substitution to solve the MMSE-IC equations while the existing systolic array architectures require 15-38 CORDIC cores to achieve a similar throughput. The proposed 4-CORDIC QRD architecture can be configured as a 16-matrix or a 64-matrix pipelining by using a different number …

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An Online Outlier Identification And Removal Scheme For Improving Fault Detection Performance, Hasan Ferdowsi, Sarangapani Jagannathan, Maciej Jan Zawodniok Jan 2014

An Online Outlier Identification And Removal Scheme For Improving Fault Detection Performance, Hasan Ferdowsi, Sarangapani Jagannathan, Maciej Jan Zawodniok

Electrical and Computer Engineering Faculty Research & Creative Works

Measured data or states for a nonlinear dynamic system is usually contaminated by outliers. Identifying and removing outliers will make the data (or system states) more trustworthy and reliable since outliers in the measured data (or states) can cause missed or false alarms during fault diagnosis. In addition, faults can make the system states nonstationary needing a novel analytical model-based fault detection (FD) framework. In this paper, an online outlier identification and removal (OIR) scheme is proposed for a nonlinear dynamic system. Since the dynamics of the system can experience unknown changes due to faults, traditional observer-based techniques cannot be …

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The Dual-Porosity Vertical-Well Model For Transient Pressure Analysis Of Naturally Fractured Shale Gas Reservoirs, Yi Jiang, Rui Xu, Meng Chen Jan 2014

The Dual-Porosity Vertical-Well Model For Transient Pressure Analysis Of Naturally Fractured Shale Gas Reservoirs, Yi Jiang, Rui Xu, Meng Chen

Electrical and Computer Engineering Faculty Research & Creative Works

During the process of development for shale gas reservoirs, the permeability of fractures will decrease due to stress-sensitive effect. Adsorption is also an important mechanism which determines the production of shale gas reservoirs. Therefore, the effect of stress sensitivity and adsorption must be considered in the numerical model for pressure transient analysis. In this paper, a dual-porosity model was established considering both mechanisms, and finite-difference method was used for discretizing fluid equations. Then Newton method was applied for solving the resulting algebraic equations, and the typical curves in terms of dimensionless pseudo pressure and time were drawn with different sets …

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Variability-Aware Parametric Yield Estimation For Analog/Mixed-Signal Circuits: Concepts, Algorithms, And Challenges, Fang Gong, Yiyu Shi, Hao Yu, Lei He Jan 2014

Variability-Aware Parametric Yield Estimation For Analog/Mixed-Signal Circuits: Concepts, Algorithms, And Challenges, Fang Gong, Yiyu Shi, Hao Yu, Lei He

Electrical and Computer Engineering Faculty Research & Creative Works

The undesired uncertainties in circuit performance can lead to analog/mixed-signal circuit failures and yield loss at nanoscale. As such, it has become extremely critical for high precision analog/RF circuits such as phase-locked loop (PLL) and custom/mixed-signal circuits such as SRAM arrays, which both have tight operating margin due to lower power supply and higher operating frequency. Many performance-domain techniques have become available in past few decades: the Monte Carlo (MC) method repeatedly draws samples, runs simulations, and evaluates the yield rate, which can be easily applied to high-dimensional problems. However, it is extremely time consuming. IS can reduce the number …

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Economic Scheduling Of Residential Plug-In (Hybrid) Electric Vehicle (Phev) Charging, Maigha, Mariesa L. Crow Jan 2014

Economic Scheduling Of Residential Plug-In (Hybrid) Electric Vehicle (Phev) Charging, Maigha, Mariesa L. Crow

Electrical and Computer Engineering Faculty Research & Creative Works

In the past decade, plug-in (hybrid) electric vehicles (PHEVs) have been widely proposed as a viable alternative to internal combustion vehicles to reduce fossil fuel emissions and dependence on petroleum. Off-peak vehicle charging is frequently proposed to reduce the stress on the electric power grid by shaping the load curve. Time of use (TOU) rates have been recommended to incentivize PHEV owners to shift their charging patterns. Many utilities are not currently equipped to provide real-time use rates to their customers but can provide two or three staggered rate levels. To date, an analysis of the optimal number of levels …

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The Soft-Feedback Isi Canceller-Based Turbo Equalizer For Multilevel Modulations, Huang Lou, Chengshan Xiao Jan 2014

The Soft-Feedback Isi Canceller-Based Turbo Equalizer For Multilevel Modulations, Huang Lou, Chengshan Xiao

Electrical and Computer Engineering Faculty Research & Creative Works

In this paper, we investigate the soft-feedback equalizer (SFE) proposed by Lopes et al. for multilevel modulations. The SFE is based on InterSymbol interference canceller structure and is compared to both soft-decision feedback turbo equalizer (SDFE) and the exact solution of MMSE linear equalizer (Exact-MMSE-LE) by means of EXIT chart analysis and BER simulations. Interesting results reveal that, for multilevel modulations, the SFE not only exhibits the same low complexity, low SNR threshold and fast convergence as SDFE but also reaches matched filter bound after a large number of iterations. © 2013 Springer Science + Business Media New York.

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Full-Quantum Simulation Of P-Type Junctionless Transistors With Multi-Band K · P Model, Jun Z. Huang, Weng Cho Chew, Li (Lijun) Jun Jiang, Jie Peng, Chi Yung Yam, Guan Hua Chen Dec 2013

Full-Quantum Simulation Of P-Type Junctionless Transistors With Multi-Band K · P Model, Jun Z. Huang, Weng Cho Chew, Li (Lijun) Jun Jiang, Jie Peng, Chi Yung Yam, Guan Hua Chen

Electrical and Computer Engineering Faculty Research & Creative Works

By adopting a model order reduction technique, we have successfully constructed a program for efficient simulation of nanowire transistors based on the multi-band k · p model and non-equilibrium Green's function (NEGF) approach. We then study for the first time the influences of various device parameters on the performances of p-type junctionless (JL) transistors and compare them to traditional inversion mode (IM) devices. © 2013 IEEE.

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Recent Development Of Surface Integral Equation Solvers For Multiscale Interconnects And Circuits, Sheng Sun, Lijun Jiang, Weng Cho Chew Dec 2013

Recent Development Of Surface Integral Equation Solvers For Multiscale Interconnects And Circuits, Sheng Sun, Lijun Jiang, Weng Cho Chew

Electrical and Computer Engineering Faculty Research & Creative Works

This paper presents a brief review and recent development of surface integral equation solvers for multiscale interconnects and circuits modeling. As the future production processes down to 5 nm and the operating frequency increases, both multi-scale and large-scale natures should be taken into account in the electromagnetic simulations. Fast, efficient, stable, and broadband integral equation based solvers become indispensable when millions or ten s of millions of unknowns might be involved in the simulation of the integrated circuit. Recent progress and our latest researches in the development of broadband fast electromagnetic solvers will be demonstrated. © 2013 IEEE.

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A Neural Network Based Outlier Identification And Removal Scheme, H. Ferdowsi, S. Jagannathan, M. Zawodniok Dec 2013

A Neural Network Based Outlier Identification And Removal Scheme, H. Ferdowsi, S. Jagannathan, M. Zawodniok

Electrical and Computer Engineering Faculty Research & Creative Works

Identifying and removing the outliers is important in order to make the data more trustworthy and improve the reliability of fault detection, since outliers in the measured data can cause false alarms. An online outlier identification and removal (OIR) scheme, suitable for nonlinear dynamic systems, is proposed in this paper. A neural network (NN) is utilized to estimate the actual outlier-free system states using only the measured system states which involve outliers. Outlier identification is performed online by finding the difference between measured and estimated states and comparing it with its median and standard deviation over a dynamic time window. …

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A Decentralized Fault Accommodation Scheme For Nonlinear Interconnected Systems, H. Ferdowsi, S. Jagannathan Dec 2013

A Decentralized Fault Accommodation Scheme For Nonlinear Interconnected Systems, H. Ferdowsi, S. Jagannathan

Electrical and Computer Engineering Faculty Research & Creative Works

In this paper, a novel decentralized detection and accommodation (FDA) methodology is proposed for interconnected nonlinear continuous-time systems by using local subsystem states alone in contrast with traditional distributed FDA schemes where the entire measured or the estimated state vector is needed. First, the detection scheme is revisited where a network of local fault detectors (LFD) is proposed. A fault is detected by generating a residual from the measured and estimated state vectors locally and the fault dynamics are estimated by using an online approximator upon detection. Subsequently, a fault accommodation scheme is initiated in the subsystem by using a …

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An Efficiently Preconditioned Eigenanalysis Of Inhomogeneously Loaded Rectangular Cavities, Qi I. Dai, Yat Hei Lo, Weng Cho Chew, Li (Lijun) Jun Jiang Dec 2013

An Efficiently Preconditioned Eigenanalysis Of Inhomogeneously Loaded Rectangular Cavities, Qi I. Dai, Yat Hei Lo, Weng Cho Chew, Li (Lijun) Jun Jiang

Electrical and Computer Engineering Faculty Research & Creative Works

In this letter, we demonstrate an efficient preconditioning scheme for the eigenanalysis of inhomogeneously loaded rectangular cavities. Modeling the entire structure with the finite-difference frequency-domain (FDFD) method yields a large sparse eigenvalue problem. The desired interior eigen-spectrum is sought for by Arnoldi iterations with the shift-and-invert operation, where the inversion can only be performed iteratively in large-scale applications. A preconditioner is constructed to speed up the inversion. It can effectively shrink the spectrum of the governing matrix and can be solved for by using fast discrete sine and cosine transforms (DSTs and DCTs). Several numerical examples are included to illustrate …

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Passivization Of Em Peec Solutions In The Frequency And Time Domain, Albert E. Ruehli, Giulio Antonini, Lijun Jiang Dec 2013

Passivization Of Em Peec Solutions In The Frequency And Time Domain, Albert E. Ruehli, Giulio Antonini, Lijun Jiang

Electrical and Computer Engineering Faculty Research & Creative Works

The stability issues for time domain integral equations is well known and it has been investigated for a long time. In this paper, we pursue an approach for the stabilization and even passivization of the electromagnetic solutions in the time and frequency domain using the PEEC circuit techniques. We aim to enhance the passivity by adding more passivization to the EM solution rather than using a post-processing technique which have to be used in the EM solver is not available. © 2013 IEEE.

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Fast And Efficient Low-Frequency Algorithms For Multiscale Structure Modeling, Sheng Sun, Zu Hui Ma, Qin S. Liu, Zhi Guo Qian, Lijun Jiang, Weng Cho Chew Dec 2013

Fast And Efficient Low-Frequency Algorithms For Multiscale Structure Modeling, Sheng Sun, Zu Hui Ma, Qin S. Liu, Zhi Guo Qian, Lijun Jiang, Weng Cho Chew

Electrical and Computer Engineering Faculty Research & Creative Works

This paper reviews our recently developed fast and efficient algorithms for multiscale structure modeling. Low-frequency electromagnetic analysis becomes indispensable for multi-scale structures because of the involved minute length-scale compared to wavelength and mid length-scale on the order of wavelength or larger, where wave physics meets circuit physics. We are currently investigating stable low-frequency solutions in solving integral equations without the need for loop-tree decomposition, including the augmented EFIE, equivalence principle based algorithms, and perturbation-based Calderon multiplicative preconditioning methods. © 2013 IEEE.

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A Novel Broadband Equivalent Source Reconstruction Method For Broadband Radiators, Ping Li, Li (Lijun) Jun Jiang, Jun Hu, Sheng Sun Dec 2013

A Novel Broadband Equivalent Source Reconstruction Method For Broadband Radiators, Ping Li, Li (Lijun) Jun Jiang, Jun Hu, Sheng Sun

Electrical and Computer Engineering Faculty Research & Creative Works

Traditional equivalent source reconstruction methods are only operating at a single frequency point each time. However, for wide band radiators, their computation cost of the source reconstruction increases linearly with the number of frequency points. In this paper, a wide-band equivalent source reconstruction method (WB-SRM) based on the Neville-type Stoer-Bulirsch (SB) algorithm is developed. Supported by the adaptive frequency sampling (AFS) scheme, the number of required sampling data is significantly reduced, which leads to much better computational efficiency. During the AFS process, three fitting models (FM) are considered: two are 'triangle rules', and another one is 'rhombus rule'. The combination …

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Limitations On High-Frequency Permeability Of Magnetic Materials, Konstantin N. Rozanov, Marina Koledintseva Dec 2013

Limitations On High-Frequency Permeability Of Magnetic Materials, Konstantin N. Rozanov, Marina Koledintseva

Electrical and Computer Engineering Faculty Research & Creative Works

Engineering of magnetic composites with high microwave permeability is important for EMC/EMI and other applications. One of the challenging problems is to determine constraints on the achievable high-frequency permeability of magnetic composites. The objective of the present paper is to analyze the data available from the literature on the microwave permeability constraints and derive a generalized constraint condition. It is well known that in many practical occasions the actual magnetic frequency dispersion curves differ from the Lorentzian behavior. For these cases, an integral form of the constraint may be useful. Possible applications of the integral constraint are discussed for the …

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A New Coulomb Gauge Based Electric Field Integral Equation Method, Xiaoyan Y.Z. Xiong, Li (Lijun) Jun Jiang, Wei E.I. Sha, Yat Hei Lo Dec 2013

A New Coulomb Gauge Based Electric Field Integral Equation Method, Xiaoyan Y.Z. Xiong, Li (Lijun) Jun Jiang, Wei E.I. Sha, Yat Hei Lo

Electrical and Computer Engineering Faculty Research & Creative Works

The electric field integral equation (EFIE) method is one of the most commonly-adopted computational electromagnetic methods. Its popularity stems from the efficient surface triangulation, excellent numerical precision, and the powerful capability of handling open and complex geometries. However, when the frequency tends to zero, the method-of-moment (MoM) solution of EFIE using the Rao-Wilton-Glisson (RWG) basis functions suffers from the low-frequency breakdown, where the contribution from the vector potential is extremely imbalanced with that from the scalar potential. As a result, the matrix representation of EFIE operator is highly ill-conditioned and cannot be inverted reliably and efficiently. © 2013 IEEE.

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Reducing Computational Workload Of Electromagnetic Scattered Fields From Electrically Large Quadratic Surface At High Frequency, Yu Mao Wu, Weng Cho Chew, Li (Lijun) Jun Jiang Dec 2013

Reducing Computational Workload Of Electromagnetic Scattered Fields From Electrically Large Quadratic Surface At High Frequency, Yu Mao Wu, Weng Cho Chew, Li (Lijun) Jun Jiang

Electrical and Computer Engineering Faculty Research & Creative Works

We use the numerical steepest descent path (NSDP) method to calculate the highly oscillatory physical optics (PO) scattered fields on electrically large quadratic surfaces. The resultant phase behaviors of PO integrands are elliptic and hyperbolic on parabolic and saddle quadratic patches, respectively. The proposed method relies on deforming the integration path of the PO integral into the NSDPs on the complex plane. Numerical results of the PO scattered fields on these smooth conducting quadratic surfaces illustrate that the proposed NSDP method gains high accuracy while the workload is frequency independent. © 2013 IEEE.

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One Dimensional Multiple Periodic Composite Right/Left Handed (Crlh) Structures, Zi Long Ma, Li (Lijun) Jun Jiang, Shulabh Gupta, Wei E.I. Sha Dec 2013

One Dimensional Multiple Periodic Composite Right/Left Handed (Crlh) Structures, Zi Long Ma, Li (Lijun) Jun Jiang, Shulabh Gupta, Wei E.I. Sha

Electrical and Computer Engineering Faculty Research & Creative Works

The wave-propagation characteristics in a one-dimensional multiple-periodic (MP) Composite right/left-handed (CRLH) structures is presented, where it is found that an increase in the number of unit cells in each supercell leads to new passbands and stopbands. To understand this phenomenon, the network parameters are employed for the theoretical analysis. Detailed dispersion characteristics and the relation between passbands and sub-periodicities are investigated using both analytical and full-wave results, and the reasons for their emergence is qualitatively discussed. Besides, its application to multi-band leaky-wave radiators is also suggested. © 2013 IEEE.

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A Compact Hf/Uhf Dual Band Rfid Tag Antenna, Zi Long Ma, Li (Lijun) Jun Jiang, Jingtian Xi, Terry Tao Ye Dec 2013

A Compact Hf/Uhf Dual Band Rfid Tag Antenna, Zi Long Ma, Li (Lijun) Jun Jiang, Jingtian Xi, Terry Tao Ye

Electrical and Computer Engineering Faculty Research & Creative Works

This paper presents a novel dual band RFID (radio frequency identification) tag antenna. Two challenges are faced: the compact dimension and the impaired bandwidth due to the couplings between two band structures. A spiral coil is designed to handle the HF (13.56MHz) near field coupling, and a diagonal symmetric design consisting of two meander lines are placed inside the coil for UHF band (915MHz). This structure supports multiple resonance modes around 915MHz to broaden the working bandwidth under the large inductive circumstance from the HF coil. The proposed antenna is easy to adjust by both coarse tuning and fine tuning. …

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An Efficient Preconditioning Scheme For Eigenanalysis Of Inhomogeneously Loaded Rectangular Cavities, Qi I. Dai, Yat Hei Lo, Lijun Jiang, Weng Cho Chew Dec 2013

An Efficient Preconditioning Scheme For Eigenanalysis Of Inhomogeneously Loaded Rectangular Cavities, Qi I. Dai, Yat Hei Lo, Lijun Jiang, Weng Cho Chew

Electrical and Computer Engineering Faculty Research & Creative Works

An efficient preconditioning scheme for the eigenanalysis of inhomogeneously loaded rectangular cavities is presented. Such structures are modeled with the finite-difference frequency-domain (FDFD) method, while the desired interior eigen-spectra are sought for by Arnoldi iterations with the shiftand-invert operation. In large scale problems, the inversion can only be performed iteratively. A preconditioner is constructed in order to accelerate the inversion. It can effectively shrink the spectrum of the governing matrix, and can be solved for by using fast discrete sine and cosine transforms (DST's and DCT's). The efficiency of this scheme is demonstrated by several numerical examples. © 2013 IEEE.

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Chipless Rfid Tags Based On Multiple Band-Rejected Planar Log-Periodic Antennas, Shulabh Gupta, Li (Lijun) Jun Jiang Dec 2013

Chipless Rfid Tags Based On Multiple Band-Rejected Planar Log-Periodic Antennas, Shulabh Gupta, Li (Lijun) Jun Jiang

Electrical and Computer Engineering Faculty Research & Creative Works

A passive chipless Radio-frequency identification (RFID) tag is proposed based on the tailorable band-rejection property of the log-periodic (LP) antennas. The proposed tag principle is successfully demonstrated using full-wave simulations, where the absence and presence of the band-rejection in VSWR and thus radiation gain, is shown to carry the bit information. Due to the large number of dipole radiators on the LP aperture, the proposed tag can easily support large number of codes, providing a potential solution for limited number of bits in conventional chipless tags. © 2013 IEEE.

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Modeling Radiated Emissions Through Shielding Boxes Based On The Tangential Electrical Field Samplings Over Openings, Ping Li, Li (Lijun) Jun Jiang Dec 2013

Modeling Radiated Emissions Through Shielding Boxes Based On The Tangential Electrical Field Samplings Over Openings, Ping Li, Li (Lijun) Jun Jiang

Electrical and Computer Engineering Faculty Research & Creative Works

The radiation from radiators such as PCBs inside an enclosed shielding box with ventilation slots is an important issue for electromagnetic compatibility or interference characterizations. In this paper, a two-step process is proposed based on the equivalence principle and the electric field integral equation method to complete the radiation prediction. The tangential electric fields over the slots on shielding boxes are first sampled to be the equivalent magnetic currents radiated from internal PCBs. In the second step, to avoid the computation of complex nonanalytical dyadic Green's functions when the field radiation is computed directly from the equivalent source, the surface …

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Degrees Of Freedom Of The Single Antenna Gaussian Wiretap Channel With A Helper Irrespective Of The Number Of Antennas At The Eavesdropper, Mohamed Nafea, Aylin Yener Dec 2013

Degrees Of Freedom Of The Single Antenna Gaussian Wiretap Channel With A Helper Irrespective Of The Number Of Antennas At The Eavesdropper, Mohamed Nafea, Aylin Yener

Electrical and Computer Engineering Faculty Research & Creative Works

A Gaussian wiretap channel with a helper, i.e., a cooperative jammer, is considered and its secure degrees of freedom (s.d.o.f.) is computed. Previous work showed that the s.d.o.f. is upper bounded by 1 over 2 in this model when all parties are equipped with one antenna each. In this paper, the more challenging scenario where the eavesdropper has multiple antennas is tackled. Relying on structured signaling and cooperative jamming, specifically, by real interference alignment, it is shown that s.d.o.f. of 1 over 2 is achievable irrespective of the number of antennas the eavesdropper may have as long as the cooperative …

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Finite Horizon Stochastic Optimal Control Of Uncertain Linear Networked Control System, Hao Xu, S. Jagannathan Dec 2013

Finite Horizon Stochastic Optimal Control Of Uncertain Linear Networked Control System, Hao Xu, S. Jagannathan

Electrical and Computer Engineering Faculty Research & Creative Works

In this paper, finite horizon stochastic optimal control issue has been studied for linear networked control system (LNCS) in the presence of network imperfections such as network-induced delays and packet losses by using adaptive dynamic programming (ADP) approach. Due to an uncertainty in system dynamics resulting from network imperfections, the stochastic optimal control design uses a novel adaptive estimator (AE) to solve the optimal regulation of uncertain LNCS in a forward-in-time manner in contrast with backward-in-time Riccati equation-based optimal control with known system dynamics. Tuning law for unknown parameters of AE has been derived. Lyapunov theory is used to show …

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