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Electrical and Computer Engineering Faculty Research & Creative Works

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Articles 1621 - 1650 of 3518

Full-Text Articles in Engineering

Optimal Location And Sizing Of Energy Storage Modules For A Smart Electric Ship Power System, Chuan Yan, Ganesh K. Venayagamoorthy, Keith Corzine Aug 2011

Optimal Location And Sizing Of Energy Storage Modules For A Smart Electric Ship Power System, Chuan Yan, Ganesh K. Venayagamoorthy, Keith Corzine

Electrical and Computer Engineering Faculty Research & Creative Works

The Navy's next generation electric ship's power system will support high energy loads and critical equipment. Energy storage modules will be needed to meet the demands of these loads as well as increase the overall high quality of service. This paper describes an approach to evaluate the impact of energy storage module location and sizing for ship survivability and quality of service. Specifically, a multi-objective optimization algorithm, the multi-objective particle swarm optimization -, is used to obtain Pareto optimal solutions considering survivability, quality of service, and cost. Results based multi-objective particle swarm optimization study show that optimal ESM location and …

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Wide Area Monitoring In Power Systems Using Cellular Neural Networks, Bipul Luitel, Ganesh K. Venayagamoorthy Aug 2011

Wide Area Monitoring In Power Systems Using Cellular Neural Networks, Bipul Luitel, Ganesh K. Venayagamoorthy

Electrical and Computer Engineering Faculty Research & Creative Works

The demand of power and the size and complexity of the power system is increasing. Wide area monitoring and control is an integral part in transitioning from the traditional power system to a Smart Grid. However, wide area monitoring becomes challenging as the size of the electric power grid, and consequently the number of components to be monitored, grows. Wide area monitor (WAM) designed using feed-forward and feedback neural network architectures do not scale up to handle the growing complexity of the Smart Grid. in this paper, cellular neural network (CNN) is presented as a way to provide scalability in …

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Adaptive Critic Design Based Dynamic Optimal Power Flow Controller For A Smart Grid, Jiaqi Liang, Ronald G. Harley, Ganesh K. Venayagamoorthy Aug 2011

Adaptive Critic Design Based Dynamic Optimal Power Flow Controller For A Smart Grid, Jiaqi Liang, Ronald G. Harley, Ganesh K. Venayagamoorthy

Electrical and Computer Engineering Faculty Research & Creative Works

An adaptive critic design (ACD) based dynamic optimal power flow control (DOPFC) is proposed in this paper as a solution to the smart grid operation in a high short-term uncertainty and variability environment. with the increasing penetration of intermittent renewable generation, power system stability and security need to be ensured dynamically as the system operating condition continuously changes. the proposed DOPFC dynamically tracks the power system optimal operating point by continuously adjusting the steady state set points from the traditional OPF algorithms. the ACD technique, specifically the dual heuristic dynamic programming (DHP), is used to provide nonlinear optimal control, where …

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The Time Machine: A Novel Spike-Based Computation Architecture, Vaibhav Garg, Ravi Shekhar, John G. Harris Aug 2011

The Time Machine: A Novel Spike-Based Computation Architecture, Vaibhav Garg, Ravi Shekhar, John G. Harris

Electrical and Computer Engineering Faculty Research & Creative Works

A novel spike-based computation architecture has been developed which represents synaptic weights in time. An analog chip with 32 neurons, 1024 synapses and an AER block has been fabricated in 0.5μm technology. A digital implementation of the architecture having 6,144 neurons and 100,352 synapses on an FPGA is also described. A digital controller for routing spikes can processes up to 34 million synapses per second. The architecture is called the time machine as it operates on timing events and uses time to store weights. The time machine is general enough for implementing many spike-based algorithms yet provides flexibility and configurability. …

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Integrate And Fire Circuit As An Adc Replacement, Manu Rastogi, Alexander Singh Alvarado, John G. Harris, José C. Principe Aug 2011

Integrate And Fire Circuit As An Adc Replacement, Manu Rastogi, Alexander Singh Alvarado, John G. Harris, José C. Principe

Electrical and Computer Engineering Faculty Research & Creative Works

We evaluate the performance of an asynchronous analog-to-digital converter known as the Integrate and Fire (I&F) circuit. The reconstruction algorithm for the sampler is presented along with the analytical results for the signal-to-noise ratio (SNR) of the reconstructed signal. We present the power vs. SNR tradeoff, based on the measurements from the chip fabricated in AMI 0.6 m technology. The figure-of-merit (FOM) of the I&F sampler is 0.6 pJ/conversion, which is comparable to the reported FOM for other synchronous and asynchronous ADCs, even though the I&F is implemented in a much older technology as compared to the other ADCs. © …

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Process-Variation-Aware Electromagnetic-Semiconductor Coupled Simulation, Yuanzhe Xu, Quan Chen, Lijun Jiang, Ngai Wong Aug 2011

Process-Variation-Aware Electromagnetic-Semiconductor Coupled Simulation, Yuanzhe Xu, Quan Chen, Lijun Jiang, Ngai Wong

Electrical and Computer Engineering Faculty Research & Creative Works

We develop a new method based on the high-frequency electromagnetic (EM)-semiconductor coupled simulation to analyze the impact of multi-type process variations happen around semi-conductormetal structure. It is competent to simultaneously handle geometrical variations like surface roughness and material variations like semi-conductor doping profile, which are difficult for traditional stand alone simulation methods. A sparse grid based stochastic spectral collocation method (SSCM) combined with principle factor analysis (PFA) is implemented to accelerate the stochastic simulation. Numerical results confirm the validity and significance of our variational coupled simulation framework. © 2011 IEEE.

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The Integrate-And-Fire Sampler: A Special Type Of Asynchronous ∑-Δ Modulator, Alexander Singh Alvarado, Manu Rastogi, John G. Harris, Jose C. Principe Aug 2011

The Integrate-And-Fire Sampler: A Special Type Of Asynchronous ∑-Δ Modulator, Alexander Singh Alvarado, Manu Rastogi, John G. Harris, Jose C. Principe

Electrical and Computer Engineering Faculty Research & Creative Works

We present the integrate-and-fire (IF) model as a time encoding scheme and show that it corresponds to a special case of the asynchronous - modulator (ASDM). We depart from typical rate-based encoding used by conventional ASDM towards time-based encoding. We show that for certain families of signals, such as neural recordings, the IF sampler accurately encodes the regions of interest at sub-Nyquist data rates. Nevertheless, the encoder requires nonlinear recovery algorithms, instead of the typical low pass filter. © 2011 IEEE.

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Enhanced Mimo Lmmse Turbo Equalization: Algorithm, Simulations, And Undersea Experimental Results, Jun Tao, Jingxian Wu, Yahong Rosa Zheng, Chengshan Xiao Aug 2011

Enhanced Mimo Lmmse Turbo Equalization: Algorithm, Simulations, And Undersea Experimental Results, Jun Tao, Jingxian Wu, Yahong Rosa Zheng, Chengshan Xiao

Electrical and Computer Engineering Faculty Research & Creative Works

In this paper, an enhanced linear minimum mean square error (LMMSE) turbo equalization scheme is proposed for multiple-input multiple-output (MIMO) communication systems with bit-interleaved coded modulation (BICM) in the time domain and multiplexing in the space domain. the proposed turbo equalization scheme outperforms the conventional LMMSE turbo equalization by adopting two new signal processing techniques. First, it performs hybrid soft interference cancellation (HSOIC) by subtracting the soft decisions of the interfering symbols, and the soft decisions are calculated by using a hybrid of the a priori information at the equalizer input and the a posteriori information at the equalizer output. …

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Dynamic, Stochastic, Computational, And Scalable Technologies For Smart Grids, Ganesh K. Venayagamoorthy Aug 2011

Dynamic, Stochastic, Computational, And Scalable Technologies For Smart Grids, Ganesh K. Venayagamoorthy

Electrical and Computer Engineering Faculty Research & Creative Works

The smart electric power grid will evolve into a very complex adaptive system under semi-autonomous distributed control. its spatial and temporal complexity, non-convexity, non-linearity, non-stationarity, variability and uncertainties exceed the characteristics found in today's traditional power system. the distributed integration of intermittent sources of energy and plug-in electric vehicles to a smart grid further adds complexity and challenges to its modeling, control and optimization. Innovative technologies are needed to handle the growing complexity of the smart grid and stochastic bidirectional optimal power flows, to maximize the penetration of renewable energy, and to provide maximum utilization of available energy storage, especially …

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Special Issue On Approximate Dynamic Programming And Reinforcement Learning, Silvia Ferrari, Jagannathan Sarangapani, Frank L. Lewis Aug 2011

Special Issue On Approximate Dynamic Programming And Reinforcement Learning, Silvia Ferrari, Jagannathan Sarangapani, Frank L. Lewis

Electrical and Computer Engineering Faculty Research & Creative Works

No abstract provided.

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Online Optimal Control Of Nonlinear Discrete-Time Systems Using Approximate Dynamic Programming, Travis Dierks, Sarangapani Jagannathan Aug 2011

Online Optimal Control Of Nonlinear Discrete-Time Systems Using Approximate Dynamic Programming, Travis Dierks, Sarangapani Jagannathan

Electrical and Computer Engineering Faculty Research & Creative Works

In this paper, the optimal control of a class of general affine nonlinear discrete-time (DT) systems is undertaken by solving the Hamilton Jacobi-Bellman (HJB) equation online and forward in time. the proposed approach, referred normally as adaptive or approximate dynamic programming (ADP), uses online approximators (OLAs) to solve the infinite horizon optimal regulation and tracking control problems for affine nonlinear DT systems in the presence of unknown internal dynamics. Both the regulation and tracking controllers are designed using OLAs to obtain the optimal feedback control signal and its associated cost function. Additionally, the tracking controller design entails a feedforward portion …

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Attenuation In Extended Structures Coated With Thin Magneto-Dielectric Absorber Layer, Marina Koledintseva, Alexander G. Razmadze, Aleksandr Yakubovich Gafarov, Victor Khilkevich, James L. Drewniak, Takanori Tsutaoka Jul 2011

Attenuation In Extended Structures Coated With Thin Magneto-Dielectric Absorber Layer, Marina Koledintseva, Alexander G. Razmadze, Aleksandr Yakubovich Gafarov, Victor Khilkevich, James L. Drewniak, Takanori Tsutaoka

Electrical and Computer Engineering Faculty Research & Creative Works

Thin absorbing layers containing magnetic alloy or ferrite inclusions can be effectively used for attenuating common-mode currents on extended structures, such as power cords, cables, or edge-coupled microstrip lines. An analytical model to evaluate attenuation on the coaxial line with the central conductor coated with a magneto-dielectric layer is proposed and validated by the experiments and numerical modeling. The analytical model is validated using available magneto-dielectric samples of different thicknesses. This model can serve for comparing and predicting the absorptive properties of different samples of magneto-dielectric materials, whose compositions may be unknown, but dielectric and magnetic properties can be determined …

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Reliability-Based Turbo Detection, Jun Tao, Jingxian Wu, Yahong Rosa Zheng Jul 2011

Reliability-Based Turbo Detection, Jun Tao, Jingxian Wu, Yahong Rosa Zheng

Electrical and Computer Engineering Faculty Research & Creative Works

This paper proposes a reliability-Based turbo detection scheme for multiple-input multiple-output (MIMO) systems with frequency-selective fading. the proposed scheme performs iterative successive soft interference cancellation (SSIC) with a block decision-feedback equalizer (BDFE). to minimize the negative impacts of error propagation in SSIC, we propose a new group-wise reliability-Based ordering scheme, where neighboring symbols that severely interfere with each other are clustered into the same group, and for each group, more "reliable" symbols are detected before less "reliable" ones. the symbol reliability is measured by using the symbol a priori probability, which is a unique byproduct of the turbo detection and …

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Localization Of Objects Using Stochastic Tunneling, Mohammed Rana Basheer, Sarangapani Jagannathan Jun 2011

Localization Of Objects Using Stochastic Tunneling, Mohammed Rana Basheer, Sarangapani Jagannathan

Electrical and Computer Engineering Faculty Research & Creative Works

This paper presents a novel wireless localization scheme in the three-dimensional domain that employs stochastic optimization with tunneling transformation to recursively estimate the location of wireless tags in a network from pair wise signal strength measurements. Spatially co-located wireless tags, receiving signals from a common transmitter, exhibit correlation in their Received Signal Strength Indicator (RSSI) values. Hence in a network of wireless tags, with pair wise correlation coefficients available, posterior distribution of the unknown tag separation is used to relatively localize them using maximum a posteriori (MAP) Estimator. However, due to the non-convex/non-tractable nature of this posterior distribution, deterministic optimization …

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Multi-Hop Framework For Battery-Less Devices Using Passive Rf Communication, Vikram Reddy Surendra, Maciej Jan Zawodniok Jun 2011

Multi-Hop Framework For Battery-Less Devices Using Passive Rf Communication, Vikram Reddy Surendra, Maciej Jan Zawodniok

Electrical and Computer Engineering Faculty Research & Creative Works

Typical wireless multi-hop networks employ active communication where RF signal is actively generated by a sending node. in contrast, backscatter communication modulates backscattered RF signal that requires significantly less energy to operate than the active one. This paper proposes a novel, multi-hop architecture for such backscatter-Based communication that is not currently present in the literature. Such a system consists of a powerful reader and small, battery-less nodes. the reader generates the original RF signal, while the passive devices backscatter this signal to communicate among themselves thus enabling multihop transmission from far-away nodes. the paper presents the generic analysis of the …

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Spectrum Management For Wireless Networks Using Adaptive Control And Game Theory, Swagoto Roy, Liuju Wu, Macie Zawodniok Jun 2011

Spectrum Management For Wireless Networks Using Adaptive Control And Game Theory, Swagoto Roy, Liuju Wu, Macie Zawodniok

Electrical and Computer Engineering Faculty Research & Creative Works

Radio frequency spectrum in wireless communication is a common resource shared by all collocated devices. Most spectrum management schemes rely on a centralized base station-receiver station relaying architecture. in contrast, infrastructure-less systems including wireless ad hoc networks require a scalable, distributed methodology. Moreover, the access has to be coordinated among the nodes in the network in the aspects which include power and rate adaptation. the challenge is to find an optimal tradeoff between such parameters not only for a particular link but also for an entire multi-hop network. Several existing schemes address power, throughput and Signal-to-Interference ratio (SIR) control on …

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Soft-Decision Feedback Turbo Equalization For Multiple Antenna Systems With Multilevel Modulations, Amirhossein Rafati, Huang Lou, Chengshan Xiao Jun 2011

Soft-Decision Feedback Turbo Equalization For Multiple Antenna Systems With Multilevel Modulations, Amirhossein Rafati, Huang Lou, Chengshan Xiao

Electrical and Computer Engineering Faculty Research & Creative Works

Many communication systems today encounter the problem of data transmission over a channel with inter-symbol interference (ISI). the purpose of this paper is to develop a low-complexity, iterative soft-decision feedback equalization (SDFE) receiver for severe, frequency selective ISI channels. the proposed SDFE algorithm offers a novel approach to combat error propagation. in addition, its computational complexity grows only linearly with the number of equalizer coefficients, compared to the quadratic complexity of minimum mean square error-Based linear turbo equalizer with time-varying coefficients. Performance of the proposed detection scheme is verified through simulations using different signal constellations. Simulation results show that our …

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A Novel Implementation Of Discrete Complex Image Method For Layered Medium Green's Function, Yongpin P. Chen, Weng Cho Chew, Lijun Jiang Jun 2011

A Novel Implementation Of Discrete Complex Image Method For Layered Medium Green's Function, Yongpin P. Chen, Weng Cho Chew, Lijun Jiang

Electrical and Computer Engineering Faculty Research & Creative Works

A novel implementation of discrete complex image method (DCIM) based on the Sommmerfeld branch cut is proposed to accurately capture the far-field behavior of the layered medium Green's function as a complement to the traditional DCIM. By contour deformation, the Green's function can be naturally decomposed into branch-cut integration (radiation modes) and pole contributions (guided modes). For branch-cut integration, matrix pencil method is applied, and the alternative Sommerfeld identity in terms of kz integration is utilized to get a closed-form solution. The guided modes are accounted for with a pole-searching algorithm. Both one-branch-cut and two-branch-cut cases are studied. Several numerical …

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Probabilistic Fatigue Life Prediction Model For Alloys With Defects: Applied To A206, R. Kapoor, Vittal S. Rao, R. S. Mishra, J. A. Baumann, G. Grant May 2011

Probabilistic Fatigue Life Prediction Model For Alloys With Defects: Applied To A206, R. Kapoor, Vittal S. Rao, R. S. Mishra, J. A. Baumann, G. Grant

Electrical and Computer Engineering Faculty Research & Creative Works

A model for the prediction of fatigue life based on the statistical distribution of pores, intermetallic particles and grains is presented here. This has been applied to a cast Al alloy A206 before and after friction stir processing (FSP). the model computes the probability of initiating a small crack based on the probability of finding combinations of defects and grains on the surface. Crack initiation and the propagation life of small cracks due to these defect and grain combinations are computed and summed to obtain the total fatigue life. the defect and grain combinations are ranked according to total fatigue …

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Numerical Characterization Of Yb-Signal-Aided Cladding-Pumped Er:Yb-Codoped Fiber Amplifiers, Qun Han, Yang He, Zhaoxia Sheng, Weiyi Zhang, Jiping Ning, Hai Xiao May 2011

Numerical Characterization Of Yb-Signal-Aided Cladding-Pumped Er:Yb-Codoped Fiber Amplifiers, Qun Han, Yang He, Zhaoxia Sheng, Weiyi Zhang, Jiping Ning, Hai Xiao

Electrical and Computer Engineering Faculty Research & Creative Works

In this Letter, high-power cladding-pumped Er:Yb-codoped fiber amplifiers (EYDFAs) coseeded with a Yb-band signal are numerically characterized according to the wavelength and power of the aiding signal, the length of the gain fiber, and the wavelength of the pump. the results show that properly designing these parameters not only helps to suppress the parasitic lasing and improve the pump conversion efficiency but also helps to improve the output power stability of high-power EYDFAs. © 2011 Optical Society of America.

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On The Secrecy Rate Of Multi-Antenna Wiretap Channel Under Finite-Alphabet Input, Shafi Bashar, Zhi Ding, Chengshan Xiao May 2011

On The Secrecy Rate Of Multi-Antenna Wiretap Channel Under Finite-Alphabet Input, Shafi Bashar, Zhi Ding, Chengshan Xiao

Electrical and Computer Engineering Faculty Research & Creative Works

This work investigates the effect of limiting source signals to finite-alphabet on the secrecy rate of a multi-antenna wiretap system. Existing works have characterized maximum achievable secrecy rate or secrecy capacity for single- and multi-antenna systems based on Gaussian source signals and secrecy code. Despite the impracticality of Gaussian source, its compact closed-form expression of mutual information motivated broad use of Gaussian input assumption. for practical consideration, we study the effect of finite discrete-constellation on instantaneous and ergodic secrecy rate of multiple-antenna wire-tap channels. Our results demonstrate substantial difference between systems involving finite-alphabet inputs and systems with Gaussian inputs. Results …

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A Case For On-Machine Load Balancing, Shoukat Ali, Behdis Eslamnour, Zehra Shah Apr 2011

A Case For On-Machine Load Balancing, Shoukat Ali, Behdis Eslamnour, Zehra Shah

Electrical and Computer Engineering Faculty Research & Creative Works

This paper diverges from the traditional load balancing, and introduces a new principle called the on-machine load balance rule. the on-machine load balance rule leads to resource allocations that are better in tolerating uncertainties in the processing times of the tasks allocated to the resources when compared to other resource allocations that are derived using the conventional "across-the-machines" load balancing rule. the on-machine load balance rule calls for the resource allocation algorithms to allocate similarly sized tasks on a machine (in addition to optimizing some primary performance measures such as estimated make span and average response time). the on-machine load …

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An Augmented Electric Field Integral Equation For Layered Medium Green's Function, Yongpin P. Chen, Lijun Jiang, Zhi Guo Qian, Weng Cho Chew Mar 2011

An Augmented Electric Field Integral Equation For Layered Medium Green's Function, Yongpin P. Chen, Lijun Jiang, Zhi Guo Qian, Weng Cho Chew

Electrical and Computer Engineering Faculty Research & Creative Works

This paper proposes an augmented electric field integral equation (A-EFIE) for layered medium Green's function. The newly developed matrix-friendly formulation of layered medium Green's function is applied in this method. By separating charge as extra unknown list, and enforcing the current continuity equation, the traditional EFIE can be cast into a generalized saddle-point system. Frequency scaling for the matrix-friendly formulation is analyzed when frequency tends to zero. Rank deficiency and the charge neutrality enforcement of the A-EFIE for layered medium Green's function is discussed in detail. The electrostatic limit of the A-EFIE is also analyzed. Without any topological loop-searching algorithm, …

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Oversampled Orthogonal Frequency Division Multiplexing In Doubly Selective Fading Channels, Jingxian Wu, Yahong Rosa Zheng Mar 2011

Oversampled Orthogonal Frequency Division Multiplexing In Doubly Selective Fading Channels, Jingxian Wu, Yahong Rosa Zheng

Electrical and Computer Engineering Faculty Research & Creative Works

A new oversampled orthogonal frequency division multiplexing (OOFDM) scheme is proposed for doubly selective fading environment. the proposed OOFDM scheme employs oversampling in the time domain and linear processing in the frequency domain, both at the receiver without changing the structure of conventional orthogonal frequency division multiplexing (OFDM) transmitters. the time-frequency processing enables a two-dimensional Doppler-frequency grid of the fading channel, such that each data symbol is modeled equivalently as being transmitted at multiple subcarriers and various Doppler spreads simultaneously, while retaining the same spectral efficiency as conventional OFDM systems. Optimum combining ensures coherent combining of the data samples spread …

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Computational Intelligence In Wireless Sensor Networks: A Survey, Raghavendra V. Kulkarni, Anna Förster, Ganesh K. Venayagamoorthy Mar 2011

Computational Intelligence In Wireless Sensor Networks: A Survey, Raghavendra V. Kulkarni, Anna Förster, Ganesh K. Venayagamoorthy

Electrical and Computer Engineering Faculty Research & Creative Works

Wireless sensor networks (WSNs) are networks of distributed autonomous devices that can sense or monitor physical or environmental conditions cooperatively. WSNs face many challenges, mainly caused by communication failures, storage and computational constraints and limited power supply. Paradigms of computational intelligence (CI) have been successfully used in recent years to address various challenges such as data aggregation and fusion, energy aware routing, task scheduling, security, optimal deployment and localization. CI provides adaptive mechanisms that exhibit intelligent behavior in complex and dynamic environments like WSNs. CI brings about flexibility, autonomous behavior, and robustness against topology changes, communication failures and scenario changes. …

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Particle Swarm Optimization In Wireless-Sensor Networks: A Brief Survey, Raghavendra V. Kulkarni, Ganesh K. Venayagamoorthy Mar 2011

Particle Swarm Optimization In Wireless-Sensor Networks: A Brief Survey, Raghavendra V. Kulkarni, Ganesh K. Venayagamoorthy

Electrical and Computer Engineering Faculty Research & Creative Works

Wireless-sensor networks (WSNs) are networks of autonomous nodes used for monitoring an environment. Developers of WSNs face challenges that arise from communication link failures, memory and computational constraints, and limited energy. Many issues in WSNs are formulated as multidimensional optimization problems and approached through bioinspired techniques. Particle swarm optimization (PSO) is a simple, effective, and computationally efficient optimization algorithm. It has been applied to address WSN issues such as optimal deployment, node localization, clustering, and data aggregation. This paper outlines issues in WSNs, introduces PSO, and discusses its suitability for WSN applications. It also presents a brief survey of how …

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Apparatus For Converting Direct Current To Alternating Current Using Multiple Converters, Patrick L. Chapman, Brian T. Kuhn, Robert S. Balog, Jonathan W. Kimball, Philip T. Krein, Alexander Gray, T. Esram Feb 2011

Apparatus For Converting Direct Current To Alternating Current Using Multiple Converters, Patrick L. Chapman, Brian T. Kuhn, Robert S. Balog, Jonathan W. Kimball, Philip T. Krein, Alexander Gray, T. Esram

Electrical and Computer Engineering Faculty Research & Creative Works

An inverter for converting an input direct current (DC) waveform from a DC source to an output alternating current (AC) waveform for delivery to an AC grid includes an input converter, an output converter, and an active filter, each of which is electrically coupled to a bus. The bus may be a DC bus or an AC bus. The input converter is configured to convert the input DC waveform to a DC or AC bus waveform. The output converter is configured to convert the bus waveform to the output AC waveform at a grid frequency. The active filter is configured …

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An Extended Cavity Method To Analyze Slot Coupling Between Printed Circuit Board Cavities, Gang Feng, Jun Fan Feb 2011

An Extended Cavity Method To Analyze Slot Coupling Between Printed Circuit Board Cavities, Gang Feng, Jun Fan

Electrical and Computer Engineering Faculty Research & Creative Works

In high-speed multilayer printed circuit boards, gaps are commonly used in planes, where different areas are utilized for different logic levels or where noise isolation from one area to another is necessary. However, these gap structures could present serious signal integrity and electromagnetic interference issues. in this paper, an extended cavity method is developed to characterize noise coupling caused by slots or gaps in the middle plane of a three-plane structure. According to the equivalence principle, the entire structure can be divided into two plane pairs without any slot in the middle plane, and then, equivalent magnetic currents are needed …

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Nanostructured Substrate With Nanoparticles Fabricated By Femtosecond Laser For Surface-Enhanced Raman Scattering, Yukun Han, Zhi Liang, Huilai Sun, Hai Xiao, Hai-Lung Tsai Feb 2011

Nanostructured Substrate With Nanoparticles Fabricated By Femtosecond Laser For Surface-Enhanced Raman Scattering, Yukun Han, Zhi Liang, Huilai Sun, Hai Xiao, Hai-Lung Tsai

Electrical and Computer Engineering Faculty Research & Creative Works

A Simple and Fast Method to Fabricate Nanostructured Substrates with Silver Nanoparticles over a Large Area for Surface-Enhanced Raman Scattering (SERS) is Reported. the Method Involves Two Steps: (1) Dip the Substrate into a Silver Nitrate Solution for a Few Minutes, Remove the Substrate from the Solution, and Then Air Dry and (2) Process the Silver Nitrate Coated Substrate by Femtosecond (Fs) Laser Pulses in Air. the Second Step Can Create Silver Nanoparticles Distributed on the Nanostructured Surface of the Substrate by the Photoreduction of Fs Multiphoton Effects. This Study Demonstrates that an Enhancement Factor (EF) Greater Than 5x105, Measured …

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A Unified Model-Based Fault Diagnosis Scheme For Nonlinear Discrete-Time Systems With Additive And Multiplicative Faults, Hasan Ferdowsi, Sarangapani Jagannathan Jan 2011

A Unified Model-Based Fault Diagnosis Scheme For Nonlinear Discrete-Time Systems With Additive And Multiplicative Faults, Hasan Ferdowsi, Sarangapani Jagannathan

Electrical and Computer Engineering Faculty Research & Creative Works

In this paper, a novel model-Based fault diagnosis scheme is proposed for a class of uncertain nonlinear discrete-time systems which can be subjected to both additive and multiplicative faults. Faults are detected by using a novel (FD) observer consisting of two online approximators in discrete-time (OLAD) and a robust adaptive term. Upon detection, a fault diagnosis scheme is introduced to determine the fault type by monitoring the input residual generated via the first OLAD output. Then the appropriate OLAD is included in the observer while the other OLAD is switched off. Next, by using both the parameter update law of …

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