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Electrical and Computer Engineering Faculty Research & Creative Works

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Full-Text Articles in Engineering

Magnetics In Smart Grid, Qi Huang, Yuanqiang Song, Xu Sun, Lijun Jiang, Philip W.T. Pong Jul 2014

Magnetics In Smart Grid, Qi Huang, Yuanqiang Song, Xu Sun, Lijun Jiang, Philip W.T. Pong

Electrical and Computer Engineering Faculty Research & Creative Works

A revolution in power transmission and distribution, driven by environmental and economic considerations, is occurring all over the world. This revolution is spearheaded by the development of the smart grid. The smart grid is bringing profound change to both the power systems and many related industries. This paper reviews the development of the smart grid and its correlation with magnetics, including electromagnetic compatibility issue, magnetic-field-based measurement/monitoring, and magnetic energy storage/conversion. The challenge to the field of magnetics and the usage of the cutting edge magnetics technology in the development of the smart grid are discussed. This paper enables researchers in …


Injection Locking Of Spin-Torque Nano-Oscillators, Chong Long Cao, Yan Zhou, Lijun Jiang, Philip W.T. Pong Jul 2014

Injection Locking Of Spin-Torque Nano-Oscillators, Chong Long Cao, Yan Zhou, Lijun Jiang, Philip W.T. Pong

Electrical and Computer Engineering Faculty Research & Creative Works

We demonstrated the phase locking of a spin-torque oscillator (STO) to an alternating current (ac) using macrospin and micromagnetic simulations. We found that the locking properties of both approaches agree with each other. The phase difference between the STO and the injected ac stabilizes at Δφ ≈ 90° and is not sensitive to the initial phase difference, which provides potential application of STO for microwave generation.


Asynchronous Advanced Encryption Standard Hardware With Random Noise Injection For Improved Side-Channel Attack Resistance, Siva Pavan Kumar Kotipalli, Yong-Bin Kim, Minsu Choi Jul 2014

Asynchronous Advanced Encryption Standard Hardware With Random Noise Injection For Improved Side-Channel Attack Resistance, Siva Pavan Kumar Kotipalli, Yong-Bin Kim, Minsu Choi

Electrical and Computer Engineering Faculty Research & Creative Works

This work presents the design, hardware implementation, and performance analysis of novel asynchronous AES (advanced encryption standard) Key Expander and Round Function, which offer increased side-channel attack (SCA) resistance. These designs are based on a delay-insensitive (DI) logic paradigm known as null convention logic (NCL), which supports useful properties for resisting SCAs including dual-rail encoding, clock-free operation, and monotonic transitions. Potential benefits include reduced and more uniform switching activities and reduced signal-to-noise (SNR) ratio. A novel method to further augment NCL AES hardware with random voltage scaling technique is also presented for additional security. Thereby, the proposed components leak significantly …


Integration Of Microwave And Thermographic Ndt Methods For Corrosion Detection, Dustin F. Pieper, Kristen M. Donnell, Mohammad Tayeb Ahmad Ghasr, Edward C. Kinzel Jul 2014

Integration Of Microwave And Thermographic Ndt Methods For Corrosion Detection, Dustin F. Pieper, Kristen M. Donnell, Mohammad Tayeb Ahmad Ghasr, Edward C. Kinzel

Electrical and Computer Engineering Faculty Research & Creative Works

Infrastructure health monitoring is an important issue in the transportation industry. For the case of cement-based structures in particular, detection of corrosion on reinforcing steel bars (rebar) is an ongoing problem for aging infrastructure. There have been a number of techniques that have shown promise in this area including microwave nondestructive testing (NDT) and thermography. Thermography is quite advantageous as it is an established method, and can be utilized for large inspection areas with intuitive results. Typical heat sources include induction heating and flash lamps, but these are not without drawbacks. Microwave nondestructive testing has also been successful at detecting …


Organizing A Student Poster Session In An Asee Section Conference, Steve Eugene Watkins, Les Kinsler, Julia L. Morse, Douglas R. Carroll Jun 2014

Organizing A Student Poster Session In An Asee Section Conference, Steve Eugene Watkins, Les Kinsler, Julia L. Morse, Douglas R. Carroll

Electrical and Computer Engineering Faculty Research & Creative Works

Student poster sessions at conferences can be valuable experiences for undergraduate and graduate students and can enrich the conference program for all participants. Student poster presentations beyond the local campus can provide additional experience in professional communication (especially in preparing succinct abstracts and in effective visual design), can prepare students for future conference participations, and can facilitate student-faculty interaction. Several issues exist when including student poster sessions in engineering education conferences. How can the content of posters be related to an engineering education theme? How are communication principles of audience and purpose incorporated into the session guidelines and review process? …


Nondestructive Evaluation Of Mechanically Stabilized Earth Walls With Frequency-Modulated Continuous Wave (Fm-Cw) Radar, Mohammad Tayeb Ahmad Ghasr, Yi Bao, Kuang Ying, K. M. Combs, R. Zoughi, Genda Chen Jun 2014

Nondestructive Evaluation Of Mechanically Stabilized Earth Walls With Frequency-Modulated Continuous Wave (Fm-Cw) Radar, Mohammad Tayeb Ahmad Ghasr, Yi Bao, Kuang Ying, K. M. Combs, R. Zoughi, Genda Chen

Electrical and Computer Engineering Faculty Research & Creative Works

Effective techniques for a nondestructive evaluation of mechanically stabilized earth (MSE) walls during normal operation or immediately after an earthquake event are yet to be developed. MSE walls often have a rough surface finishing for the purpose of decoration and are reinforced with both horizontal and vertical steel bars. Two wide-band microwave inspection approaches were investigated for detecting and evaluating characteristics of materials behind an MSE wall section. The first approach used spot measurements with a wide-band frequency-modulated continuous wave (FM-CW) radar system. While effective to penetrate through mortar blocks in the laboratory, the radar system was found to have …


Simultaneous Measurement Of Temperature And Pressure With Cascaded Extrinsic Fabry-Perot Interferometer And Intrinsic Fabry-Perot Interferometer Sensors, Yinan Zhang, Jie Huang, Xinwei Lan, Lei Yuan, Hai Xiao Jun 2014

Simultaneous Measurement Of Temperature And Pressure With Cascaded Extrinsic Fabry-Perot Interferometer And Intrinsic Fabry-Perot Interferometer Sensors, Yinan Zhang, Jie Huang, Xinwei Lan, Lei Yuan, Hai Xiao

Electrical and Computer Engineering Faculty Research & Creative Works

This paper presents an approach for simultaneous measurement of temperature and pressure using miniaturized fiber inline sensors. The approach utilizes the cascaded optical fiber inline intrinsic Fabry-Perot interferometer and extrinsic Fabry-Perot interferometer as temperature and pressure sensing elements, respectively. A CO2 laser was used to create a loss between them to balance their reflection power levels. The multiplexed signals were demodulated using a Fast Fourier transform-based wavelength tracking method. Experimental results showed that the sensing system could measure temperature and pressure unambiguously in a pressure range of 0 to 6.895 x 105 Pa and a temperature range from …


On Over-Determined Frequency Domain Bss, Christopher Osterwise, Steven L. Grant May 2014

On Over-Determined Frequency Domain Bss, Christopher Osterwise, Steven L. Grant

Electrical and Computer Engineering Faculty Research & Creative Works

This paper introduces two new frequency domain overdetermined blind source separation (BSS) algorithms: Inter-frequency Correlation with Microphone Diversity (ICMD), and ICA with Triggered Principal component analysis (ITP). In the first, we consider different sets of microphones, where in each set the number of microphones and sources are equal. In the second, we extract principal components from an overdetermined mixture to form a determined mixture for separation. Both techniques utilize inter-frequency correlation to align permutations via energy profiles. Both monitor the condition number of an inter-frequency cross-correlation matrix of the normalized de-mixed signals' envelopes to determine if separation has failed for …


Through-Silicon-Via Inductor: Is It Real Or Just A Fantasy?, Umamaheswara Rao Tida, Cheng Zhuo, Yiyu Shi Mar 2014

Through-Silicon-Via Inductor: Is It Real Or Just A Fantasy?, Umamaheswara Rao Tida, Cheng Zhuo, Yiyu Shi

Electrical and Computer Engineering Faculty Research & Creative Works

Through-silicon-vias (TSVs) can potentially be used to implement inductors in three-dimensional (3D) integrated systems for minimal footprint and large inductance. However, different from conventional 2D spiral inductors, TSV inductors are fully buried in the lossy substrate, thus suffering from low quality factor. In this paper, we propose a novel shield mechanism utilizing the micro-channel, a technique conventionally used for heat removal, to reduce the substrate loss. This technique increases the quality factor and the inductance of the TSV inductor by up to 21x and 17x respectively. It enables us to implement TSV inductors of up to 38x smaller area and …


Log-Periodic Dipole Array Antenna As Chipless Rfid Tag, S. Gupta, Gui Jun Li, R. C. Roberts, Li (Lijun) Jun Jiang Feb 2014

Log-Periodic Dipole Array Antenna As Chipless Rfid Tag, S. Gupta, Gui Jun Li, R. C. Roberts, Li (Lijun) Jun Jiang

Electrical and Computer Engineering Faculty Research & Creative Works

A passive chipless radio-frequency identification (RFID) tag based on a log-periodic (LP) dipole array is proposed, where the tailorable bandrejection property of the LP aperture is utilised to realise a large number of codes. The proposed tag principle is successfully validated by measurements, where the absence and presence of the band-rejection is shown to carry the bit information. Its fabrication simplicity is also demonstrated by its implementation on a flexible substrate. Finally, two different tag formation schemes, based on a specific set of resonance suppressions, are discussed in detail. © 2014 The Institution of Engineering and Technology.


Exploring Demand Flexibility In Heterogeneous Aggregators: An Lmp-Based Pricing Scheme, Chenye Wu, Yiyu Shi, Soummya Kar Feb 2014

Exploring Demand Flexibility In Heterogeneous Aggregators: An Lmp-Based Pricing Scheme, Chenye Wu, Yiyu Shi, Soummya Kar

Electrical and Computer Engineering Faculty Research & Creative Works

With the proposed penetration of electric vehicles and advanced metering technology, the demand side is foreseen to play a major role in flexible energy consumption scheduling. On the other hand, the past several years has witnessed utility companies' growing interests to integrate more renewable energy resources. These renewable resources, for example, wind or solar, due to their intermittent nature, brought great uncertainty to the power grid system. In this article, we propose a mechanism that attempts to mitigate the grid operational uncertainty induced by renewable energies by properly exploiting demand flexibility with the help of advanced smart-metering technology. To address …


Communicating In A Socially-Aware Network: Impact Of Relationship Types, Basak Guler, Burak Varan, Kaya Tutuncuoglu, Mohamed Nafea, Ahmed A. Zewail, Aylin Yener, Damien Octeau Feb 2014

Communicating In A Socially-Aware Network: Impact Of Relationship Types, Basak Guler, Burak Varan, Kaya Tutuncuoglu, Mohamed Nafea, Ahmed A. Zewail, Aylin Yener, Damien Octeau

Electrical and Computer Engineering Faculty Research & Creative Works

Communication networks are linked to and influenced by human interactions. Socially aware systems should integrate these complex relationship patterns in the network design. This paper studies the impact of friendship and antagonistic relationships between individuals on optimal network propagation policies. We develop a network propagation model for signed networks and determine the optimal policies to influence a target node with an opinion while minimizing the total number of persons against it. We also provide extensions to this problem to elaborate on the impact of network parameters, such as minimum-delay propagation, while limiting the number of persons influenced against the idea …


An Event-Based Simulation Framework To Examine The Response Of Power Grid To The Charging Demand Of Plug-In Hybrid Electric Vehicles, Zahra Darabi, Mehdi Ferdowsi Feb 2014

An Event-Based Simulation Framework To Examine The Response Of Power Grid To The Charging Demand Of Plug-In Hybrid Electric Vehicles, Zahra Darabi, Mehdi Ferdowsi

Electrical and Computer Engineering Faculty Research & Creative Works

This paper describes the development of a discrete-event simulation framework that emulates the interactions between the power grid and plug-in hybrid electric vehicles (PHEVs) and examines whether the capacity of the existing power system can meet the PHEV load demand. The probability distribution functions for the arrival time and energy demand of each vehicle are extracted from real-world statistical transportation data. The power grid's limited generation and transmission capacities are considered to be the major constraints. Therefore, vehicles may have to wait to receive any charge. The proposed simulation framework is justified and described in some detail in applying it …


Energy Efficiency And Spectral Efficiency Tradeoff In Type-I Arq Systems, Jingxian Wu, Gang Wang, Yahong Rosa Zheng Feb 2014

Energy Efficiency And Spectral Efficiency Tradeoff In Type-I Arq Systems, Jingxian Wu, Gang Wang, Yahong Rosa Zheng

Electrical and Computer Engineering Faculty Research & Creative Works

The optimum energy efficient and spectral efficient designs for type-I automatic-repeat-request (ARQ) systems in Rayleigh flat fading channels are studied in this paper. Three optimum designs are considered: the first scheme maximizes the energy efficiency (EE), or equivalently, minimizes the total energy per information bit without considering the spectral efficiency (SE); the second scheme minimizes a new metric, the energy per information bit normalized by the SE; and the third scheme maximizes the EE under the constraint of a minimum SE. For given physical and link layer parameters, such as hardware power consumption, coding rate, modulation, bit rate, number of …


Multi-Terminal Networks With An Untrusted Relay, Ahmed A. Zewail, Mohamed Nafea, Aylin Yener Jan 2014

Multi-Terminal Networks With An Untrusted Relay, Ahmed A. Zewail, Mohamed Nafea, Aylin Yener

Electrical and Computer Engineering Faculty Research & Creative Works

This paper investigates the impact of cooperation with an untrusted relay in multi-source multi-destination networks. The set up considered is one where the relay is the only means of communications due to the absence of direct links between the sources and the destinations. Since the relay is untrusted, all messages from the sources need to be kept secret from the relay. Furthermore, the destinations are assumed to have different levels of security clearance, i.e., some private messages should only be decoded by their intended receiver and should be kept secret from other destinations. An achievable secure rate region is found …


Model-Free Q-Learning Over Finite Horizon For Uncertain Linear Continuous-Time Systems, Hao Xu, S. Jagannathan Jan 2014

Model-Free Q-Learning Over Finite Horizon For Uncertain Linear Continuous-Time Systems, Hao Xu, S. Jagannathan

Electrical and Computer Engineering Faculty Research & Creative Works

In this paper, a novel optimal control over finite horizon has been introduced for linear continuous-time systems by using adaptive dynamic programming (ADP). First, a new time-varying Q-function parameterization and its estimator are introduced. Subsequently, Q-function estimator is tuned online by using both Bellman equation in integral form and terminal cost. Eventually, near optimal control gain is obtained by using the Q-function estimator. All the closed-loop signals are shown to be bounded by using Lyapunov stability analysis where bounds are functions of initial conditions and final time while the estimated control signal converges close to the optimal value. The simulation …


Event-Based Optimal Regulator Design For Nonlinear Networked Control Systems, Avimanyu Sahoo, Hao Xu, S. Jagannathan Jan 2014

Event-Based Optimal Regulator Design For Nonlinear Networked Control Systems, Avimanyu Sahoo, Hao Xu, S. Jagannathan

Electrical and Computer Engineering Faculty Research & Creative Works

This paper presents a novel stochastic event-based near optimal control strategy to regulate a networked control system (NCS) represented as an uncertain nonlinear continuous time system. An online stochastic actor-critic neural network (NN) based approach is utilized to achieve the near optimal regulation in the presence of network constraints, such as, network induced time-varying delays and random packet losses under event-based transmission of the feedback signals. The transformed nonlinear NCS in discrete-time after the incorporation the delays and packet losses are utilized for the actor-critic NN based controller design. To relax the knowledge of the control coefficient matrix, a NN …


Neural Network-Based Adaptive Optimal Consensus Control Of Leaderless Networked Mobile Robots, Haci Mehmet Guzey, Hao Xu, S. Jagannathan Jan 2014

Neural Network-Based Adaptive Optimal Consensus Control Of Leaderless Networked Mobile Robots, Haci Mehmet Guzey, Hao Xu, S. Jagannathan

Electrical and Computer Engineering Faculty Research & Creative Works

A novel neural network (NN)-based optimal adaptive consensus control scheme is introduced in this paper for networked mobile robots in the presence of unknown robot dynamics. Throughout the paper, two NNs are used. The unknown formation dynamics of each robot is identified by using the first NN. The second NN is utilized to approximate a novel value function derived in this paper as a function of augmented error vector, which is comprised of the regulation and consensus-based formation errors of each robot. A novel near optimal controller is developed by using approximated value function and identified formation dynamics. The Lyapunov …


Hidden Markov Model With Information Criteria Clustering And Extreme Learning Machine Regression For Wind Forecasting, Dao Lam, Shuhui Li, Donald C. Wunsch Jan 2014

Hidden Markov Model With Information Criteria Clustering And Extreme Learning Machine Regression For Wind Forecasting, Dao Lam, Shuhui Li, Donald C. Wunsch

Electrical and Computer Engineering Faculty Research & Creative Works

This paper proposes a procedural pipeline for wind forecasting based on clustering and regression. First, the data are clustered into groups sharing similar dynamic properties. Then, data in the same cluster are used to train the neural network that predicts wind speed. For clustering, a hidden Markov model (HMM) and the modified Bayesian information criteria (BIC) are incorporated in a new method of clustering time series data. to forecast wind, a new method for wind time series data forecasting is developed based on the extreme learning machine (ELM). the clustering results improve the accuracy of the proposed method of wind …


Unveiling Magnetic Dipole Radiation In Phase-Reversal Leaky-Wave Antennas, Shulabh Gupta, Li (Lijun) Jun Jiang, Christophe Caloz Jan 2014

Unveiling Magnetic Dipole Radiation In Phase-Reversal Leaky-Wave Antennas, Shulabh Gupta, Li (Lijun) Jun Jiang, Christophe Caloz

Electrical and Computer Engineering Faculty Research & Creative Works

The radiation principle of traveling-wave-type phase-reversal antennas is explained in detail, unveiling the presence of magnetic-dipole radiation in addition to well-known electric dipole radiation. It is pointed out that such magnetic-dipole radiation is specific to the case of traveling-wave phase-reversal antennas, whereas only electric-dipole radiation exists in resonant-type phase-reversal antennas. It is shown that a phase-reversal traveling-wave antenna alternately operates as an array of magnetic dipoles and an array of electric dipoles during a time-harmonic period. This radiation mechanism is confirmed through both full-wave and experimental results. © 2014 IEEE.


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 …


A Static Voltage Security Region For Centralized Wind Power Integration-Part Ii: Applications, Tao Ding, Qinglai Guo, Rui Bo, Hongbin Sun, Boming Zhang, Tianen Huang Jan 2014

A Static Voltage Security Region For Centralized Wind Power Integration-Part Ii: Applications, Tao Ding, Qinglai Guo, Rui Bo, Hongbin Sun, Boming Zhang, Tianen Huang

Electrical and Computer Engineering Faculty Research & Creative Works

In Part I of this work, a static voltage security region was introduced to guarantee the safety of wind farm reactive power outputs under both base conditions and N-1 contingency. In this paper, a mathematical representation of the approximate N-1 security region has further studied to provide better coordination among wind farms and help prevent cascading tripping following a single wind farm trip. Besides, the influence of active power on the security region is studied. The proposed methods are demonstrated for N-1 contingency cases in a nine-bus system. The simulations verify that the N-1 security region is a small subset …


Overexpression Of Dcf1 Inhibits Glioma Through Destruction Of Mitochondria And Activation Of Apoptosis Pathway, Yuqiong Xie, Qang Li, Qingbo Yang Jan 2014

Overexpression Of Dcf1 Inhibits Glioma Through Destruction Of Mitochondria And Activation Of Apoptosis Pathway, Yuqiong Xie, Qang Li, Qingbo Yang

Electrical and Computer Engineering Faculty Research & Creative Works

Gliomas are the most common brain tumors affecting the central nervous system and are associated with a high mortality rate. DCF1 is a membrane protein that was previously found to play a role in neural stem cell differentiation. In the present study, we found that overexpression of dcf1 significantly inhibited cell proliferation, migration, and invasion and dramatically promoted apoptosis in the glioblastoma U251 cell line. DCF1 deletion mutations in the functional region showed that the complete structure of DCF1 was necessary for apoptosis. Furthermore, significantly lower tumorigenicity was observed in athymic nude mice by transplanting U251 cells overexpressing dcf1. To …


Data Pattern Based Electromagnetic Interference Modeling For Ic Packaging, Nick K.H. Huang, Tao Wang, Li (Lijun) Jun Jiang, X. Y. Xiong Jan 2014

Data Pattern Based Electromagnetic Interference Modeling For Ic Packaging, Nick K.H. Huang, Tao Wang, Li (Lijun) Jun Jiang, X. Y. Xiong

Electrical and Computer Engineering Faculty Research & Creative Works

Electromagnetic interference (EMI) is becoming more serious when the data rate of the digital system continues increasing. However, its modeling and analysis are very challenging. In this paper, a novel electromagnetic superposition method is developed to model the IC packaging electromagnetic emission. It employs the equivalence principle to obtain the electromagnetic field response over a broad spectrum. Then it uses the linear property of the passive parasitic system to superpose the contribution of different signals on the packaging. As a result, with certain pre-calculations, it is convenient to compute the electromagnetic emission efficiently from different signals with various data pattern …


Overhead High-Voltage Transmission-Line Current Monitoring By Magnetoresistive Sensors And Current Source Reconstruction At Transmission Tower, X. Sun, Q. Huang, L. (Lijun) J. Jiang, P. W.T. Pong Jan 2014

Overhead High-Voltage Transmission-Line Current Monitoring By Magnetoresistive Sensors And Current Source Reconstruction At Transmission Tower, X. Sun, Q. Huang, L. (Lijun) J. Jiang, P. W.T. Pong

Electrical and Computer Engineering Faculty Research & Creative Works

This paper proposes a novel current monitoring technology based on magnetic field sensing at a transmission tower for overhead high-voltage transmission lines (HVTLs), which can accurately measure phase current parameters in real time. This technology is based on the phenomenon that the magnetic field distribution at the top level of a transmission tower can reflect the operation states of the transmission lines including current amplitude and phase angle imbalances. A current source reconstruction method based on stochastic optimization strategy was developed to reconstruct the electrical parameters from the magnetic field emanated by the overhead transmission lines. This concept of current …


A New Efficient Method For Analysis Of Finite Periodic Structures, Xiaoyan Y.Z. Xiong, Ling Ling Meng, Li (Lijun) Jun Jiang, Wei E.I. Sha Jan 2014

A New Efficient Method For Analysis Of Finite Periodic Structures, Xiaoyan Y.Z. Xiong, Ling Ling Meng, Li (Lijun) Jun Jiang, Wei E.I. Sha

Electrical and Computer Engineering Faculty Research & Creative Works

The electromagnetic modeling of practical finite periodic structures is a topic of growing interest. Due to the truncation of the infinite periodic structures, surface waves will be excited and localized near the discontinuous interfaces leading to the edge effect of finite structures. In this work, surface waves are numerically disentangled from the propagating Bloch waves contributions. Based on the universally exponential decay feature of the surface waves, a novel method is developed by connecting the solution to the large finite periodic structure with that to a relatively small one resulting in low complexity and memory consumption. The method numerically reconstructs …


A Rigorous Approach For The Radiated Emission Characterization Based On The Spherical Magnetic Field Scanning, Ping Li, Li (Lijun) Jun Jiang Jan 2014

A Rigorous Approach For The Radiated Emission Characterization Based On The Spherical Magnetic Field Scanning, Ping Li, Li (Lijun) Jun Jiang

Electrical and Computer Engineering Faculty Research & Creative Works

Electromagnetic radiated emissions from antennas, printed circuit boards (PCBs), and electronic devices are becoming increasingly critical to today's IC electromagnetic compatibility and interference properties. In this paper, a rigorous characterization approach is proposed. The electromagnetic field sampling over a spherical testing surface is applied to obtain the radiated magnetic field of the device under test (DUT) placed at the center of the sampling region. Using the dyadic Green's function (DGF) and Huygens' principle, the transformation from the sampled spherical tangential field to the far field is directly computed without resorting to the conventional inverse algorithm. The DGF considers the existence …


Generalized Modal Expansion And Reduced Modal Representation Of 3-D Electromagnetic Fields, Qi I. Dai, Yat Hei Lo, Weng Cho Chew, Yang G. Liu, Li (Lijun) Jun Jiang Jan 2014

Generalized Modal Expansion And Reduced Modal Representation Of 3-D Electromagnetic Fields, Qi I. Dai, Yat Hei Lo, Weng Cho Chew, Yang G. Liu, Li (Lijun) Jun Jiang

Electrical and Computer Engineering Faculty Research & Creative Works

A generalized modal expansion theory for investigating arbitrary 3-D bounded and unbounded electromagnetic fields is presented. When an inhomogeneity is enclosed with impenetrable boundaries, the field excited by arbitrary sources is expanded with a complete set of eigenmodes, which are classified into trapped modes and radiation modes. As the boundaries tend to infinity, trapped modes remain unchanged, while radiation modes form a continuum. To illustrate the theory, several real-life structures are investigated with a conformal finite-difference technique in the frequency domain. Perfectly matched layers (PMLs) are imposed at finite extent to emulate the unbounded problems. Numerical examples show that, only …


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 …


Event-Triggered Optimal Regulation Of Uncertain Linear Discrete-Time Systems By Using Q-Learning Scheme, Avimanyu Sahoo, S. Jagannathan Jan 2014

Event-Triggered Optimal Regulation Of Uncertain Linear Discrete-Time Systems By Using Q-Learning Scheme, Avimanyu Sahoo, S. Jagannathan

Electrical and Computer Engineering Faculty Research & Creative Works

In this paper, an event-triggered optimal adaptive regulation of an uncertain linear discrete time system is proposed. This scheme solves the optimal control in a forward in- time and online manner by using both dynamic programming and Q learning. First, the time varying action dependent value or the Q-function is estimated online by an adaptive value function estimator (VFE) with event-based state vector and a time dependent basis function. The estimated value function parameters are subsequently used to generate the optimal control gain matrix. Further, aperiodic tuning law for the VFE parameters is proposed not only to estimate the parameters …