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Electrical and Computer Engineering Faculty Research & Creative Works

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Full-Text Articles in Engineering

On The Arq Protocols Over The Z-Interference Channels: Diversity- Multiplexing-Delay Tradeoff, Mohamed S. Nafea, D. Hamza, Karim G. Seddik, Mohamed Nafie, Hesham El Gamal Oct 2012

On The Arq Protocols Over The Z-Interference Channels: Diversity- Multiplexing-Delay Tradeoff, Mohamed S. Nafea, D. Hamza, Karim G. Seddik, Mohamed Nafie, Hesham El Gamal

Electrical and Computer Engineering Faculty Research & Creative Works

We characterize the achievable three-dimensional tradeoff between diversity, multiplexing, and delay of the single antenna Automatic Retransmission reQuest (ARQ) Z-interference channel. Non-cooperative and cooperative ARQ protocols are adopted under these assumptions. Considering no cooperation exists, we study the achievable tradeoff of the fixed-power split Han-Kobayashi (HK) approach. Interestingly, we demonstrate that if the second user transmits the common part only of its message in the event of its successful decoding and a decoding failure at the first user, communication is improved over that achieved by keeping or stopping the transmission of both the common and private messages. Under cooperation, two …

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A New Green's Function Formulation For Modeling Homogeneous Objects In Layered Medium, Yongpin P. Chen, Weng Cho Chew, Lijun Jiang Oct 2012

A New Green's Function Formulation For Modeling Homogeneous Objects In Layered Medium, Yongpin P. Chen, Weng Cho Chew, Lijun Jiang

Electrical and Computer Engineering Faculty Research & Creative Works

A new Green's function formulation is developed systematically for modeling general homogeneous (dielectric or magnetic) objects in a layered medium. The dyadic form of the Green's function is first derived based on the pilot vector potential approach. The matrix representation in the moment method implementation is then derived by applying integration by parts and vector identities. The line integral issue in the matrix representation is investigated, based on the continuity property of the propagation factor and the consistency of the primary term and the secondary term. The extinction theorem is then revisited in the inhomogeneous background and a surface integral …

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Generalized Modal Expansion Of Electromagnetic Field In 2-D Bounded And Unbounded Media, Qi I. Dai, Weng Cho Chew, Yat Hei Lo, Yang G. Liu, Li (Lijun) Jun Jiang Oct 2012

Generalized Modal Expansion Of Electromagnetic Field In 2-D Bounded And Unbounded Media, Qi I. Dai, Weng Cho Chew, Yat Hei Lo, Yang G. Liu, Li (Lijun) Jun Jiang

Electrical and Computer Engineering Faculty Research & Creative Works

A generalized modal expansion theory is presented to investigate and illustrate the physics of wave-matter interaction within arbitrary two-dimensional (2-D) bounded and unbounded electromagnetic problems. We start with the bounded case where the field excited by any sources is expanded with a complete set of biorthogonal eigenmodes. In regard to non-Hermitian or nonreciprocal problems, an auxiliary system is constructed to seek for the modal-expansion solution. We arrive at the unbounded case when the boundary tends to infinity or is replaced by the perfectly matched layer (PML). Modes are approximately categorized into two types: trapped modes and radiation modes, which respond …

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Microwave And Millimeter-Wave Sensors, Systems, And Techniques For Electromagnetic Imaging And Materials Characterization, Andrea Randazzo, Kristen M. Donnell, Yeousong Lee Oct 2012

Microwave And Millimeter-Wave Sensors, Systems, And Techniques For Electromagnetic Imaging And Materials Characterization, Andrea Randazzo, Kristen M. Donnell, Yeousong Lee

Electrical and Computer Engineering Faculty Research & Creative Works

No abstract provided.

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On Secrecy Rate Analysis Of Mimo Wiretap Channels Driven By Finite-Alphabet Input, Shafi Bashar, Zhi Ding, Chengshan Xiao Sep 2012

On Secrecy Rate Analysis Of Mimo Wiretap Channels Driven By Finite-Alphabet Input, Shafi Bashar, Zhi Ding, Chengshan Xiao

Electrical and Computer Engineering Faculty Research & Creative Works

This work investigates the effect of finite-alphabet input constraint on the secrecy rate of a multi-antenna wiretap channel. Most existing works have characterized maximum achievable secrecy rate or secrecy capacity for single and multiple antenna systems based on Gaussian source signals and secrecy code. for practical considerations, we study the effect of finite discrete-constellation on the achievable secrecy rate of multiple-antenna wire-tap channels. Our proposed precoding scheme converts the underlying multi-antenna system into a bank of parallel channels. based on this precoding strategy, we develop a decentralized power allocation algorithm based on dual decomposition to maximize the achievable secrecy rate. …

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Mimo Multichannel Beamforming In Rayleigh-Product Channels With Arbitrary-Power Co-Channel Interference And Noise, Yongpeng Wu, Shi Jin, Xiqi Gao, Chengshan Xiao, Matthew R. Mckay Sep 2012

Mimo Multichannel Beamforming In Rayleigh-Product Channels With Arbitrary-Power Co-Channel Interference And Noise, Yongpeng Wu, Shi Jin, Xiqi Gao, Chengshan Xiao, Matthew R. Mckay

Electrical and Computer Engineering Faculty Research & Creative Works

This paper investigates communication over multiple-input multiple-output Rayleigh-product channels in the presence of both co-channel interference and thermal noise. We first present exact expressions for the marginal ordered eigenvalue distributions of the channel Gram matrix when multichannel beamforming is employed, from which we obtain exact results on the outage probability on each eigenmode. Our results are applicable to an extensive class of multichannel systems with generic system configurations. for particular scenarios of single-input multiple-output, keyhole, and multiple-input single-output channels, simplified closed-form expressions for the asymptotic distributions of the non-zero eigenvalue of the channel Gram matrix are derived. These results indicate …

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Study On Spontaneous Emission In Complex Multilayered Plasmonic System Via Surface Integral Equation Approach With Layered Medium Green's Function, Yongpin P. Chen, Wei E.I. Sha, Wallace C.H. Choy, Lijun Jiang, Weng Cho Chew Aug 2012

Study On Spontaneous Emission In Complex Multilayered Plasmonic System Via Surface Integral Equation Approach With Layered Medium Green's Function, Yongpin P. Chen, Wei E.I. Sha, Wallace C.H. Choy, Lijun Jiang, Weng Cho Chew

Electrical and Computer Engineering Faculty Research & Creative Works

A rigorous surface integral equation approach is proposed to study the spontaneous emission of a quantum emitter embedded in a multi-layered plasmonic structure with the presence of arbitrarily shaped metallic nanoscatterers. With the aid of the Fermi's golden rule, the spontaneous emission of the emitter can be calculated from the local density of states, which can be further expressed by the imaginary part of the dyadic Green's function of the whole electromagnetic system. To obtain this Green's function numerically, a surface integral equation is established taking into account the scattering from the metallic nanoscatterers. Particularly, the modeling of the planar …

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Adaptive Dynamic Programming-Based State Quantized Networked Control System Without Value And/Or Policy Iterations, Qiming Zhao, Hao Xu, S. Jagannathan Aug 2012

Adaptive Dynamic Programming-Based State Quantized Networked Control System Without Value And/Or Policy Iterations, Qiming Zhao, Hao Xu, S. Jagannathan

Electrical and Computer Engineering Faculty Research & Creative Works

In this paper, the Bellman equation is used to solve the stochastic optimal control of unknown linear discrete-time system with communication imperfections including random delays, packet losses and quantization. a dynamic quantizer for the sensor measurements is proposed which essentially provides system states to the controller. to eliminate the effect of the quantization error, the dynamics of the quantization error bound and an update law for tuning its range are derived. Subsequently, by using adaptive dynamic programming technique, the infinite horizon optimal regulation of the uncertain NCS is solved in a forward-in-time manner without using value and/or policy iterations by …

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A Decentralized Fault Detection And Prediction Scheme For Nonlinear Interconnected Continuous-Time Systems, Hasan Ferdowsi, Deepthi L. Raja, S. Jagannathan Aug 2012

A Decentralized Fault Detection And Prediction Scheme For Nonlinear Interconnected Continuous-Time Systems, Hasan Ferdowsi, Deepthi L. Raja, S. Jagannathan

Electrical and Computer Engineering Faculty Research & Creative Works

Complex nonlinear systems such as an aircraft, trains, automobiles, power plants and chemical plants are represented as nonlinear interconnected subsystems. Therefore, in this paper a novel decentralized fault diagnosis and prognosis (FDP) methodology is proposed for such large-scale systems. Current FDP approaches require the knowledge of the entire state or its estimated vector. But the main goal in this work is to design a local fault detector (LFD) or observer for each subsystem based on the measured local states of the subsystem alone. a local residual signal is generated via the measured states of the local subsystem and the estimated …

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Studies Of Tem Mode Assumption On Via Holes In Via Modelings, Yaojiang Zhang, Shenhui Jing, Jun Fan Aug 2012

Studies Of Tem Mode Assumption On Via Holes In Via Modelings, Yaojiang Zhang, Shenhui Jing, Jun Fan

Electrical and Computer Engineering Faculty Research & Creative Works

The assumption of transverse electromagnetic (TEM) field distribution on via holes is checked by a two-dimensional (2D) finite difference method (FDM). It is found that for a via without pad, TEM mode assumption is a quite good approximation. However, for a via with a pad, i.e. the via pad radius is different from the via barrel radius, the field distribution on the via hole begins to deviate from the TEM mode. This indicates previous analytical formula for a via with pad may need to be modified at very high frequencies due to its usage of TEM field assumption on via …

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Ais-Based Coordinated And Adaptive Control Of Generator Excitation Systems For An Electric Ship, Chuan Yan, Ganesh Kumar Venayagamoorthy, Keith Corzine Aug 2012

Ais-Based Coordinated And Adaptive Control Of Generator Excitation Systems For An Electric Ship, Chuan Yan, Ganesh Kumar Venayagamoorthy, Keith Corzine

Electrical and Computer Engineering Faculty Research & Creative Works

An artificial immune system (AIS)-Based control of generator excitation systems for the U.S. Navy's electric ship is presented in this paper to solve power quality problems caused by high-energy loads such as direct energy weapons. the coordinated development of the AIS controllers mainly consists of two parts innate immunity (optimal) and adaptive immunity. the parameters of the controllers for the former, to provide optimal performance, are determined simultaneously using particle swarm optimization. for dramatic changes in the ship's power system, adaptive control based on the immune system feedback law is developed. the feedback law adapts the controllers' parameters only during …

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Parameterized Model Order Reduction Of Delayed Systems Using An Interpolation Approach With Amplitude And Frequency Scaling Coefficients, F. Ferranti, M. Nakhla, G. Antonini, T. Dhaene, L. Knockaert, Albert E. Ruehli Jul 2012

Parameterized Model Order Reduction Of Delayed Systems Using An Interpolation Approach With Amplitude And Frequency Scaling Coefficients, F. Ferranti, M. Nakhla, G. Antonini, T. Dhaene, L. Knockaert, Albert E. Ruehli

Electrical and Computer Engineering Faculty Research & Creative Works

When the geometric dimensions become electrically large or signal waveform rise times decrease, time delays must be included in the modeling. We present an innovative PMOR technique for neutral delayed differential systems, which is based on an efficient and reliable combination of univariate model order reduction methods, amplitude and frequency scaling coefficients and positive interpolation schemes. It is able to provide parameterized reduced order models passive by construction over the design space of interest. Pertinent numerical examples validate the proposed PMOR approach. © 2012 IEEE.

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A Master-Slave Soc Structure For Hmm Based Speech Recognition, Hui Geng, Yiyu Shi, Ming Dong, Runsheng Liu Jul 2012

A Master-Slave Soc Structure For Hmm Based Speech Recognition, Hui Geng, Yiyu Shi, Ming Dong, Runsheng Liu

Electrical and Computer Engineering Faculty Research & Creative Works

In this paper, we propose a master-slave SoC structure composed of an ARM7-TDMI and a co-processor for Mahala Nobis distance calculation. the SoC was implemented on an Actel ProASIC series M7A3P1000 FPGA. Furthermore, we implement a HMM based speech recognition system based on this SoC. Compared with the conventional ASIC co-processor and slave SoC structure, the new master-slave structure reduces the number of SRAM access and improves the bus efficiency. Experiment results show that with 1.40s Chinese speech feixi and 24MHz clock, the processing time of the M-S SoC system is 1.85s, a 64.12% reduction compared with the software implement …

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Linear Precoding For Finite-Alphabet Signaling Over Mimome Wiretap Channels, Yongpeng Wu, Chengshan Xiao, Zhi Ding, Xiqi Gao, Shi Jin Jul 2012

Linear Precoding For Finite-Alphabet Signaling Over Mimome Wiretap Channels, Yongpeng Wu, Chengshan Xiao, Zhi Ding, Xiqi Gao, Shi Jin

Electrical and Computer Engineering Faculty Research & Creative Works

In this paper, we investigate the secrecy rate of finite-alphabet communications over multiple-input-multiple-output-multiple-antenna eavesdropper (MIMOME) channels. Traditional precoding designs based on Gaussian input assumption may lead to substantial secrecy rate loss when the Gaussian input is replaced by practical finite-alphabet input. to address this issue, we investigate linear precoding designs to directly maximize the secrecy rate for MIMOME systems under the constraint of finite-alphabet input. by exploiting the theory of Karush-Kuhn-Tucker (KKT) analysis and matrix calculus, we first present necessary conditions of the optimal precoding design when instantaneous channel-state information (CSI) of the eavesdropper is known at the transmitter. in …

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Microwave Absorption Characteristics Of Substituted Ba 0.5sr 0.5m Xfe (12-2x)O 19 (M = Co ²⁺-Zr 4+ And Co 2+-Ti 4+) Sintered Ferrite At X-Band, Charanjeet Singh, S. Bindra Narang, Marina Koledintseva Jul 2012

Microwave Absorption Characteristics Of Substituted Ba 0.5sr 0.5m Xfe (12-2x)O 19 (M = Co ²⁺-Zr 4+ And Co 2+-Ti 4+) Sintered Ferrite At X-Band, Charanjeet Singh, S. Bindra Narang, Marina Koledintseva

Electrical and Computer Engineering Faculty Research & Creative Works

The microwave reflection loss (RL) of four series of synthesized ferrites, Ba0.5Sr0.5CoxZrxFe(12 - 2x)O19 and Ba0.5Sr0.5CoxTixFe(12 - 2x)O19, have been measured using network analyzer in the frequency range from 8.2 to 12.4 GHz. The comprehensive analysis of RL is carried out as a function of substitution, frequency, and thickness. The various models contributing to large RL are described. The composition accompanying maximum microwave absorption is suggested. © 2012 Wiley Periodicals, Inc.

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Simultaneous Evaluation Of Multiple Key Material Properties Of Complex Stratified Structures With Large Spatial Extent, Mojtaba Behzad Fallahpour, Hamed Kajbaf, Mohammad Tayeb Ahmad Ghasr, Joseph Toby Case, R. Zoughi Jul 2012

Simultaneous Evaluation Of Multiple Key Material Properties Of Complex Stratified Structures With Large Spatial Extent, Mojtaba Behzad Fallahpour, Hamed Kajbaf, Mohammad Tayeb Ahmad Ghasr, Joseph Toby Case, R. Zoughi

Electrical and Computer Engineering Faculty Research & Creative Works

Measured complex reflection coefficient of a spatially-extended stratified composite structure, using an open-ended waveguide, can be effectively used to extract key material and geometrical characteristics of any given layer. This is accomplished using a combination of an electromagnetic model and corresponding measurement data. Previously, it was shown that one parameter can be extracted if all others are known. However, practically it is desirable to extract as many pieces of information as possible. To this end the model must be "inverted". However, there is no closed-form solution for the inverse problem, given the mathematical complexity of the forward model. Consequently, we …

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Initial Study And Verification Of A Distributed Fiber Optic Corrosion Monitoring System For Transportation Structures, Hai Xiao, Genda Chen, Zhan Gao, Ying Huang, Fujian Tang Jul 2012

Initial Study And Verification Of A Distributed Fiber Optic Corrosion Monitoring System For Transportation Structures, Hai Xiao, Genda Chen, Zhan Gao, Ying Huang, Fujian Tang

Electrical and Computer Engineering Faculty Research & Creative Works

For this study, a novel optical fiber sensing system was developed and tested for the monitoring of corrosion in transportation systems. The optical fiber sensing system consists of a reference long period fiber gratings (LPFG) sensor for corrosive environmental monitoring and a LPFG sensor coated with a thin film of nano iron and silica particles for steel corrosion monitoring. The environmental effects (such as pH and temperature) are compensated by the use of the reference LPFG sensor. The sensor design, simulation, and experimental validation were performed in this study to investigate the feasibility of the proposed sensing system for corrosion …

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Methods For Fast Evaluation Of Self-Energy Matrices In Tight-Binding Modeling Of Electron Transport Systems, Jun Z. Huang, Weng Cho Chew, Yumao Wu, Li (Lijun) Jun Jiang Jul 2012

Methods For Fast Evaluation Of Self-Energy Matrices In Tight-Binding Modeling Of Electron Transport Systems, Jun Z. Huang, Weng Cho Chew, Yumao Wu, Li (Lijun) Jun Jiang

Electrical and Computer Engineering Faculty Research & Creative Works

Simulation of quantum carrier transport in nanodevices with non-equilibrium Green's function approach is computationally very challenging. One major part of the computational burden is the calculation of self-energy matrices. The calculation in tight-binding schemes usually requires dealing with matrices of the size of a unit cell in the leads. Since a unit cell always consists of several planes (for example, in silicon nanowire, four atomic planes for [100] crystal orientation and six for [111] and [112]), we show in this paper that a condensed Hamiltonian matrix can be constructed with reduced dimension (∼ 1 / 4 of the original size …

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Alternative Aefie-Efie Method For Broadband Cem Simulations, Jia Liu, Lijun Jiang Jul 2012

Alternative Aefie-Efie Method For Broadband Cem Simulations, Jia Liu, Lijun Jiang

Electrical and Computer Engineering Faculty Research & Creative Works

It is well known that electric field integral equation (EFIE) has the low frequency breakdown problem due to the decoupling of electric and magnetic field. Augmented electric field integral equation (AEFIE) method overcomes the low frequency breakdown. However, its performance degrades with the increasing frequency. To obtain a unified method that works for both low and high frequencies, a novel method using the EFIE complement process inside AEFIE is proposed. Numerical results demonstrated that this alternative AEFIE-EFIE method is able to extend integral equations to wide band applications. © 2012 Wiley Periodicals, Inc.

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An Oxidase-Based Electrochemical Fluidic Sensor With High-Sensitivity And Low-Interference By On-Chip Oxygen Manipulation, Nitin Radhakrishnan, Jongwon Park, Chang Soo Kim Jul 2012

An Oxidase-Based Electrochemical Fluidic Sensor With High-Sensitivity And Low-Interference By On-Chip Oxygen Manipulation, Nitin Radhakrishnan, Jongwon Park, Chang Soo Kim

Electrical and Computer Engineering Faculty Research & Creative Works

Utilizing a simple fluidic structure, we demonstrate the improved performance of oxidase-Based enzymatic biosensors. Electrolysis of water is utilized to generate bubbles to manipulate the oxygen microenvironment close to the biosensor in a fluidic channel. for the proper enzyme reactions to occur, a simple mechanical procedure of manipulating bubbles was developed to maximize the oxygen level while minimizing the pH change after electrolysis. the sensors show improved sensitivities based on the oxygen dependency of enzyme reaction. in addition, this oxygen-rich operation minimizes the ratio of electrochemical interference signal by ascorbic acid during sensor operation (i.e., amperometric detection of hydrogen peroxide). …

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Efficient Wakeup Scheduling Considering Both Resource Usage And Timing Budget For Power Gating Designs, Ming Chao Lee, Yiyu Shi, Shih Chieh Chang Jun 2012

Efficient Wakeup Scheduling Considering Both Resource Usage And Timing Budget For Power Gating Designs, Ming Chao Lee, Yiyu Shi, Shih Chieh Chang

Electrical and Computer Engineering Faculty Research & Creative Works

Power gating has been a very effective way to reduce power leakage. Normally, wakeup scheduling is required to control the turn-on times of sleep transistors to limit the surge current during the wakeup process. in this paper, a voltage sensor is adopted to compare the virtual ground voltage with the predesigned reference voltages and use the result to determine the turn-on times of sleep transistors. We then propose a novel wakeup scheduling formulation that considers the tradeoff between wakeup times and hardware resources incurred by the voltage sensor. to address this problem, on the one hand, an efficient algorithm is …

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Laboratory-Based Microgrid Setup For Validating Frequency And Voltage Control In Islanded And Grid-Connected Modes, Shyam N. Bhaskara, Md Rasheduzzaman, Badrul H. Chowdhury Jun 2012

Laboratory-Based Microgrid Setup For Validating Frequency And Voltage Control In Islanded And Grid-Connected Modes, Shyam N. Bhaskara, Md Rasheduzzaman, Badrul H. Chowdhury

Electrical and Computer Engineering Faculty Research & Creative Works

Small sized synchronous generator based distributed generators (DG) often have low start-up times, and therefore serve as valuable dispatchable generators in a microgrid environment. the advantage is that it allows the power network to operate in a true smart grid environment. the disadvantage is that such DGs typically tend to have low inertia and the prime movers driving these resources need to be controlled in real time for them to operate effectively in islanded, grid-connected modes and during transition. When multiple DGs are present in the microgrid, the overall control can become complicated because of the need for sharing the …

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Automated Tongue Feature Extraction For Zheng Classification In Traditional Chinese Medicine, Ratchadaporn Kanawong, Tayo Obafemi-Ajayi, Tao Ma, Dong Xu, Shao Li, Ye Duan Jun 2012

Automated Tongue Feature Extraction For Zheng Classification In Traditional Chinese Medicine, Ratchadaporn Kanawong, Tayo Obafemi-Ajayi, Tao Ma, Dong Xu, Shao Li, Ye Duan

Electrical and Computer Engineering Faculty Research & Creative Works

ZHENG, Traditional Chinese Medicine syndrome, is an integral and essential part of Traditional Chinese Medicine theory. It defines the theoretical abstraction of the symptom profiles of individual patients and thus, used as a guideline in disease classification in Chinese medicine. For example, patients suffering from gastritis may be classified as Cold or Hot ZHENG, whereas patients with different diseases may be classified under the same ZHENG. Tongue appearance is a valuable diagnostic tool for determining ZHENG in patients. In this paper, we explore new modalities for the clinical characterization of ZHENG using various supervised machine learning algorithms. We propose a …

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Linear Precoding For Mimo Broadcast Channels With Finite-Alphabet Constraints, Yongpeng Wu, Mingxi Wang, Chengshan Xiao, Zhi Ding, Xiqi Gao Jun 2012

Linear Precoding For Mimo Broadcast Channels With Finite-Alphabet Constraints, Yongpeng Wu, Mingxi Wang, Chengshan Xiao, Zhi Ding, Xiqi Gao

Electrical and Computer Engineering Faculty Research & Creative Works

We investigate the design of linear transmit precoder for multiple-input multiple-output (MIMO) broadcast channels (BC) with finite alphabet input signals. We first derive an explicit expression for the achievable rate region of the MIMO BC with discrete constellation inputs, which is generally applicable to cases involving arbitrary user number and arbitrary antenna number. We further present a weighted sum rate upper bound of the MIMO BC with identical transmit precoding matrices. the resulting bound exhibits a serious performance loss because of the non-uniquely decodable transmit signals for MIMO BC with finite alphabet inputs in high signal-to-noise ratio (SNR) region. This …

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Common-Path Endoscopic Optical Coherence Tomography Application To Human Internal Organs Detection, Yanjun Li, Yinan Zhang, Xinwei Lan, Hai Xiao Jun 2012

Common-Path Endoscopic Optical Coherence Tomography Application To Human Internal Organs Detection, Yanjun Li, Yinan Zhang, Xinwei Lan, Hai Xiao

Electrical and Computer Engineering Faculty Research & Creative Works

Due to the small volume of incipient Pathological Cells, the conventional imaging methods cannot effectively diagnose early-stage cytopathic effect. Since the spatial resolution of optical coherence tomography (OCT) can reach the magnitude of micron, and if OCT probe possesses the characteristic of small fabric and nice flexibility in order to easily enter human body, OCT probe can detect the cytopathic effect in a very early-stage. So, this article first introduces some existent common-path OCT system and then compares the advantages and the disadvantages of each CP-EOCT. Finally, this article mainly researches on a new common-path Endoscopic OCT (CP-EOCT) which possesses …

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Linear Precoding For Finite-Alphabet Inputs Over Mimo Fading Channels With Statistical Csi, Weiliang Zeng, Chengshan Xiao, Mingxi Wang, Jianhua Lu Jun 2012

Linear Precoding For Finite-Alphabet Inputs Over Mimo Fading Channels With Statistical Csi, Weiliang Zeng, Chengshan Xiao, Mingxi Wang, Jianhua Lu

Electrical and Computer Engineering Faculty Research & Creative Works

This paper investigates the linear precoder design that maximizes the average mutual information of multiple-input multiple-output fading channels with statistical channel state information known at the transmitter. It formulates the design from the standpoint of finite-alphabet inputs, which leads to a problem that is very important in practice but extremely difficult in theory: First, the average mutual information lacks closed-form expression and involves prohibitive computational burden. Second, the optimization over the precoder is nonconcave and thus easily gets stuck in local maxima. to address these issues, this study first derives lower and upper bounds for the average mutual information, in …

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A Generalized Multiple Scattering Method For Dense Vias With Axially Anisotropic Modes In An Arbitrarily Shaped Plate Pair, Yaojiang Zhang, Jun Fan May 2012

A Generalized Multiple Scattering Method For Dense Vias With Axially Anisotropic Modes In An Arbitrarily Shaped Plate Pair, Yaojiang Zhang, Jun Fan

Electrical and Computer Engineering Faculty Research & Creative Works

Numerical addition theorems of both axially anisotropic and axially isotropic parallel-plate modes are derived using a method based on boundary integral equations. This leads to a generalized multiple scattering (GMS) method for signal/power integrity analysis of dense vias in an arbitrarily shaped plate pair, which overcomes the limitation of the conventional multiple scattering method depending on the analytical addition theorems in an infinitely large or a finite circular plate pair. Both the numerical addition theorems and the GMS method have been validated by comparing results with either analytical expressions for special cases or full-wave simulations for more general cases. Several …

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Efficient Variation-Aware Em-Semiconductor Coupled Solver For The Tsv Structures In 3d Ic, Yuanzhe Xu, Wenjian Yu, Quan Chen, Lijun Jiang, Ngai Wong May 2012

Efficient Variation-Aware Em-Semiconductor Coupled Solver For The Tsv Structures In 3d Ic, Yuanzhe Xu, Wenjian Yu, Quan Chen, Lijun Jiang, Ngai Wong

Electrical and Computer Engineering Faculty Research & Creative Works

In this paper, we present a variational electromagnetic-semiconductor coupled solver to assess the impacts of process variations on the 3D integrated circuit (3D IC) on-chip structures. The solver employs the finite volume method (FVM) to handle a system of equation considering both the full-wave electromagnetic effects and semiconductor effects. With a smart geometrical variation model for the FVM discretization, the solver is able to handle both small-size or large-size variations. Moreover, a weighted principle factor analysis (wPFA) technique is presented to reduce the random variables in both electromagnetic and semiconductor regions, and the spectral stochastic collocation method (SSCM) [10] is …

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Overlapping Partitioning Techniques For Simulation Of Strongly Coupled Distributed Interconnects, Mina A. Farhan, Natalie M. Nakhla, Michel S. Nakhla, Ramachandra Achar, Albert E. Ruehli May 2012

Overlapping Partitioning Techniques For Simulation Of Strongly Coupled Distributed Interconnects, Mina A. Farhan, Natalie M. Nakhla, Michel S. Nakhla, Ramachandra Achar, Albert E. Ruehli

Electrical and Computer Engineering Faculty Research & Creative Works

The large number of interconnects in high-speed circuits is a major bottleneck for fast simulation of such circuits. Recently, waveform relaxation methods based on transverse partitioning (WR-TP) were proposed to address this issue. It was shown that the complexity of WR-TP grows only linearly with the number of lines. However, as the coupling between the lines becomes stronger, the WR-TP algorithm either fails to converge or the number of iterations required for convergence increases. in this paper, an overlapping partitioning method for WR-TP is presented, which overcomes the effect of strong coupling between the lines. Numerical examples are presented which …

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Accuracy Of Physics-Based Via Models For Simulation Of Dense Via Arrays, Sebastian Müller, Xiaomin Duan, Miroslav Kotzev, Yaojiang Zhang, Jun Fan, Xiaoxiong Gu, Young H. Kwark, Renato Rimolo-Donadio, Heinz Dietrich Brüns, Christian Schuster May 2012

Accuracy Of Physics-Based Via Models For Simulation Of Dense Via Arrays, Sebastian Müller, Xiaomin Duan, Miroslav Kotzev, Yaojiang Zhang, Jun Fan, Xiaoxiong Gu, Young H. Kwark, Renato Rimolo-Donadio, Heinz Dietrich Brüns, Christian Schuster

Electrical and Computer Engineering Faculty Research & Creative Works

This paper studies the accuracy of the physics-Based via model, specifically when applied to dense via arrays. the physics-Based model uses Greens functions for cylindrical waves in radial waveguides to model the via return current paths and the coupling between vias. the effects of approximations made in this model are studied with regard to four types of modes based on an eigenmode expansion for the radial waveguide. It is found that for the mode conversion in the vicinity of the via, an accurate consideration of Non propagating modes becomes critical with an increasing cavity height. for the interaction between vias …

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