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Electrical and Computer Engineering Faculty Research & Creative Works

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Articles 1441 - 1470 of 3518

Full-Text Articles in Engineering

A Low Complexity Algorithm For Linear Precoder Design With Finite Alphabet Inputs, Mingxi Wang, Yahong Rosa Zheng, Chengshan Xiao, Weiliang Zeng Dec 2012

A Low Complexity Algorithm For Linear Precoder Design With Finite Alphabet Inputs, Mingxi Wang, Yahong Rosa Zheng, Chengshan Xiao, Weiliang Zeng

Electrical and Computer Engineering Faculty Research & Creative Works

A low complexity precoding method is proposed for practical multiple-input multiple-output (MIMO) systems. based on the two-step optimal precoder design algorithm that maximizes the lower bound of the mutual information with finite-alphabet inputs, the proposed method simplifies the precoder design by fixing the right singular vectors of the precoder matrix to be the modulation diversity matrix, eliminating the iterative optimization between the two steps, and discretizing the search space of the power allocation vector. the modulation diversity matrices are designed for different modulations, which outperform the existing maximum diversity for BPSK and 8PSK inputs. for a 4x4 channel, the computational …

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Linear Precoding Of Finite Alphabet Signals In Multi-Antenna Broadcast Channels, Yongpeng Wu, Mingxi Wang, Chengshan Xiao, Zhi Ding, Xiqi Gao Dec 2012

Linear Precoding Of Finite Alphabet Signals In Multi-Antenna Broadcast Channels, 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 precoding for multiple-input multiple-output (MIMO) broadcast channels (BC) with finite alphabet input signals. We 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 configurations. for the case where all the users employ the same modulation scheme, we further present a weighted sum rate upper-bound of the MIMO BC with identical transmit precoding matrices. the resulting bound demonstrates a serious performance loss due to multi-user interference for MIMO BC with finite alphabet inputs …

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On The Diversity Gain Region Of The Z-Interference Channels, Mohamed S. Nafea, Karim G. Seddik, Mohammed Nafie, Hesham El Gamal Dec 2012

On The Diversity Gain Region Of The Z-Interference Channels, Mohamed S. Nafea, Karim G. Seddik, Mohammed Nafie, Hesham El Gamal

Electrical and Computer Engineering Faculty Research & Creative Works

In this work, we analyze the diversity gain region (DGR) of the single-antenna Rayleigh fading Z-Interference channel (ZIC). More specifically, we characterize the achievable DGR of the fixed-power split Han-Kobayashi (HK) approach under these assumptions. Our characterization comes in a closed form and demonstrates that the HK scheme with only a common message is a singular case, which achieves the best DGR among all HK schemes for certain multiplexing gains. Finally, we show that generalized time sharing, with variable rate and power assignments for the common and private messages, does not improve the achievable DGR. © 2012 IEEE.

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Dual Pn Padding Tds-Ofdm For Underwater Acoustic Communication, Jinxing Hao, Yahong Rosa Zheng, Jintao Wang, Jian Song Dec 2012

Dual Pn Padding Tds-Ofdm For Underwater Acoustic Communication, Jinxing Hao, Yahong Rosa Zheng, Jintao Wang, Jian Song

Electrical and Computer Engineering Faculty Research & Creative Works

A time domain synchronous orthogonal frequency division multiplexing (TDS-OFDM) scheme with dual Pseudo noise (PN) sequence is proposed for underwater acoustic (UWA) communication. Instead of using cyclic prefix (CP) or zero padding (ZP) as the guard interval, the proposed TDS-OFDM scheme uses two identical PN sequences as guard interval and utilizes them for frame synchronization and channel estimation. the proposed TDS-OFDM increases the spectrum efficiency over the conventional CP or ZP OFDM systems where additional pilots have to be inserted for channel estimation. with the dual PN at each frame header, compressed sensing channel estimation is adopted, and a rather …

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Efficiency Optimization Of A Sensorless V/F Control Method For Pmsm, Seyed Hesam Jafari, Keith Corzine, Jing Huang Dec 2012

Efficiency Optimization Of A Sensorless V/F Control Method For Pmsm, Seyed Hesam Jafari, Keith Corzine, Jing Huang

Electrical and Computer Engineering Faculty Research & Creative Works

This paper presents a V/f control for permanent magnet synchronous machines which focuses on optimization by minimizing the d-axis current in order to reduce the motor losses and supplied input power. the proposed sensor less method only needs machine terminal signals and does not require any additional motor parameter measurements. Minimization of the d-axis current is accomplished through computed reactive power. © 2012 IEEE.

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On Linear Precoding Of Non-Regenerative Mimo Relays For Qam Inputs, Xiao Liang, Zhi Ding, Chengshan Xiao Dec 2012

On Linear Precoding Of Non-Regenerative Mimo Relays For Qam Inputs, Xiao Liang, Zhi Ding, Chengshan Xiao

Electrical and Computer Engineering Faculty Research & Creative Works

Recent works have established that MIMO systems optimized for Gaussian source signals may suffer unexpected performance loss when practical inputs are in fact discrete QAM sources. There is a practical need in the optimization of MIMO related systems of various networking scenarios to specifically target source signals of finite QAM alphabet. in this work, we investigate the precoding optimization of wireless two-hop non-regenerative three-node MIMO relay networks driven by finite-alphabet inputs. Exploiting a known optimal structure for the precoder at relay and a special convexity property, we propose an iterative two-step numerical optimization algorithm. This algorithm is a general solution, …

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Single-Carrier Frequency-Domain Turbo Equalization Without Cyclic Prefix Or Zero Padding For Underwater Acoustic Communications, Longbao Wang, Jun Tao, Yahong Rosa Zheng Dec 2012

Single-Carrier Frequency-Domain Turbo Equalization Without Cyclic Prefix Or Zero Padding For Underwater Acoustic Communications, Longbao Wang, Jun Tao, Yahong Rosa Zheng

Electrical and Computer Engineering Faculty Research & Creative Works

A frequency-domain turbo equalization (FDTE) scheme without cyclic prefix (CP) or zero padding is proposed for single-carrier, multiple-input-multiple- output underwater acoustic communication. in the first iteration of the FDTE, the received continuous data stream is divided into consecutive blocks and a combined inter-block-interference (IBI) cancellation and overlapped windowing scheme is used to diagonalize each data block for low-complexity detection in the frequency domain. Since the second iteration, IBI cancellation and CP reconstruction are applied on each block to enable effective symbol detection. This work extends the authors previous work on frequency-domain hard-decision equalization to soft-decision turbo equalization so that it …

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Wide Area Monitoring Of Rotor Angle Based On Synchrophasor Measurements, P. K. Olulope, Ganesh K. Venayagamoorthy, K. A. Folly Dec 2012

Wide Area Monitoring Of Rotor Angle Based On Synchrophasor Measurements, P. K. Olulope, Ganesh K. Venayagamoorthy, K. A. Folly

Electrical and Computer Engineering Faculty Research & Creative Works

The concept of phasor is designed for steady state and phasor measurement unit (PMU) is based on this concept. Measuring rotor angle therefore during transient has become a challenging task. This paper investigates the possibility of using data from PMU to estimate the internal variables of synchronous generator such as rotor angle of large power system during transient disturbance. the rotor angle is estimated from synchro phasor such as phasor voltage and current as well as their angles. the proposed method is implemented on IEEE 68 bus system. © 2012 IEEE.

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Colorimetric Oxygen Imaging And Quantification With Easily Accessible Optical Devices, Satya Achanta, Sanghan Park, Chang-Soo Kim Dec 2012

Colorimetric Oxygen Imaging And Quantification With Easily Accessible Optical Devices, Satya Achanta, Sanghan Park, Chang-Soo Kim

Electrical and Computer Engineering Faculty Research & Creative Works

Optical oxygen imaging is essential in monitoring two-dimensional analysis of oxygen distribution. Two easily accessible optical devices were used for oxygen analysis to demonstrate the feasibility of an innovatively simple method. a light panel screen with light-emitting diode (LED) backlight was used as a light source to excite a luminophore film responsive to oxygen. Meso-scale fluidic sensor platform was prepared using porphyrin complex (PtOEP) as the luminophore embedded within ethyl cellulose (EC) polymer matrix. Green LED light uniformly displayed from the light panel excited the luminophore film to exhibit two-dimensional luminescence distribution corresponding to wet gaseous oxygen. a color camera …

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On Interference-Aware Precoding For Multi-Antenna Channels With Finite-Alphabet Inputs, Weiliang Zeng, Chengshan Xiao, Jianhua Lu Dec 2012

On Interference-Aware Precoding For Multi-Antenna Channels With Finite-Alphabet Inputs, Weiliang Zeng, Chengshan Xiao, Jianhua Lu

Electrical and Computer Engineering Faculty Research & Creative Works

This paper investigates the interference-aware linear precoder design with finite-alphabet inputs. It maximizes the mutual information between the transmitter and intended receiver while controlling the interference power caused to unintended receivers. for this nonconcave problem, this work proposes a global optimization approach, which is based on two key observations: 1) the interference-aware precoding problem can be reformulated to the problem minimizing a function with bilinear terms over the intersection of multiple co-centered ellipsoids; 2) these bilinear terms can be relaxed by their convex and concave envelopes. in this way, the global optimal solution is obtained by solving a sequence of …

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Accurate And Efficient Computation Of Power Plane Pair Inductance, Liang Li, Albert E. Ruehli, Jun Fan Dec 2012

Accurate And Efficient Computation Of Power Plane Pair Inductance, Liang Li, Albert E. Ruehli, Jun Fan

Electrical and Computer Engineering Faculty Research & Creative Works

The computation of the power-plane inductance for multiple ports is an important part of the PDN design. in this paper, we present an efficient approach for the inductance computation. Since this PEEC approach is based on partial inductance computations, vias and other discontinuities can accurately be taken into account. Speed-up techniques are employed like the faster decay of the coupling due to the symmetry, sparsification and simplification of the partial mutual inductance evaluation. Also, an approximate rectangular mesh reduction method is introduced which allows a local increase in mesh density. © 2012 IEEE.

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Rssi-Based Localization In Cellular Networks, Lei Wang, Maciej Zawodniok Dec 2012

Rssi-Based Localization In Cellular Networks, Lei Wang, Maciej Zawodniok

Electrical and Computer Engineering Faculty Research & Creative Works

This paper presents a novel RSSI based localization scheme that employs an existing cellular network infrastructure to perform trilateration. Traditional localization schemes employ RSSI-Based radial distance estimation and trilateration algorithm. However, in a realistic scenario, the RSSI measurements are distorted due to multipath fading thus introducing error in radial distance estimation. Moreover, the selection of the best three anchor cell towers with the lowest localization error is not explored. the proposed scheme improves localization accuracy using two, novel correcting and evaluating metrics: The Radial Distance Error Indicator (RDEI) and the Localization Error Indicator (LEI). the proposed RDEI metric is derived …

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Skin-Effect Model For Round Wires In Peec, Albert E. Ruehli, Giulio Antonini, Lijun Jiang Dec 2012

Skin-Effect Model For Round Wires In Peec, Albert E. Ruehli, Giulio Antonini, Lijun Jiang

Electrical and Computer Engineering Faculty Research & Creative Works

In this paper we consider the skin-and radiation effects for a thin wire segment. Circuit models are being constructed which are suitable for the modeling of thin wires like the wire bonds. We use the internal-external inductance model for this purpose of including the skin-effect in the partial inductance. These models make it possible to include thin, round conductors in a PEEC model at a much lower cost in compute time. The ultimate goal is to construct a circuit model which can be applied both in the time and frequency domain to signal and power integrity problems. © 2012 IEEE.

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Linear Mimo Precoding In Multi-Antenna Wiretap Channels For Finite-Alphabet Data, Yongpeng Wu, Chengshan Xiao, Zhi Ding, Xiqi Gao, Shi Jin Dec 2012

Linear Mimo Precoding In Multi-Antenna Wiretap Channels For Finite-Alphabet Data, 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) systems. Traditional precoder designs at the transmitter for achieving secrecy capacity (maximum secrecy rate) for MIMOME systems are developed according to the assumption of Gaussian input signals. Such designs may risk substantial secrecy rate loss when Gaussian inputs are replaced by practical finite alphabet inputs. to address this issue, we propose a linear precoding design to directly maximize the secrecy rate for MIMOME systems under the constraint of finite alphabet input. Exploiting convex optimization and matrix calculus, we present necessary conditions required …

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Online Optimal Control Of Affine Nonlinear Discrete-Time Systems With Unknown Internal Dynamics By Using Time-Based Policy Update, Travis Dierks, Sarangapani Jagannathan Dec 2012

Online Optimal Control Of Affine Nonlinear Discrete-Time Systems With Unknown Internal Dynamics By Using Time-Based Policy Update, Travis Dierks, Sarangapani Jagannathan

Electrical and Computer Engineering Faculty Research & Creative Works

In this paper, the Hamilton-Jacobi-Bellman equation is solved forward-in-time for the optimal control of a class of general affine nonlinear discrete-time systems without using value and policy iterations. the proposed approach, referred to as adaptive dynamic programming, uses two neural networks (NNs), to solve the infinite horizon optimal regulation control of affine nonlinear discrete-time systems in the presence of unknown internal dynamics and a known control coefficient matrix. One NN approximates the cost function and is referred to as the critic NN, while the second NN generates the control input and is referred to as the action NN. the cost …

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A Cross Layer Approach To The Novel Distributed Scheduling Protocol And Event-Triggered Controller Design For Cyber Physical Systems, Hao Xu, Sarangapani Jagannathan Dec 2012

A Cross Layer Approach To The Novel Distributed Scheduling Protocol And Event-Triggered Controller Design For Cyber Physical Systems, Hao Xu, Sarangapani Jagannathan

Electrical and Computer Engineering Faculty Research & Creative Works

In Cyber Physical Systems (CPS), multiple real-time dynamic systems are connected to their corresponding controllers through a shared communication network in contrast with a dedicated line. for such CPS, the existing scheduling schemes for instance Centralized or Distributed Scheduling schemes are unsuitable since the behavior of real-time dynamic systems is ignored during the network protocol design. Therefore, in this paper, a novel distributed scheduling protocol design via cross-layer approach is proposed to optimize the performance of CPS by maximizing the utility function which is generated by using the information collected from both the application and network layers. Subsequently, a novel …

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Video Compressive Sensing With 3-D Wavelet And 3-D Noiselet, Dao Lam, Donald C. Wunsch Dec 2012

Video Compressive Sensing With 3-D Wavelet And 3-D Noiselet, Dao Lam, Donald C. Wunsch

Electrical and Computer Engineering Faculty Research & Creative Works

A new compressive video sampling method is investigated. as opposed to other video sampling methods for which processing is conducted on a single-frame basis, this method is applied on multiple frames of the video stream. by exploiting the extension of Wavelet to 3-D with the support of Noiselet 3-D and combining it with fast reconstruction algorithms, this framework produces successful results quickly while maintaining the quality of the video stream. Despite its simplicity, this new approach outperforms other sophisticated methods. © 2012 IEEE.

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Tdma For Wireless Passive Backscatter Networks: An Information Theoretic Approach, Aditya V. Padaki, Maciej Zawodniok Dec 2012

Tdma For Wireless Passive Backscatter Networks: An Information Theoretic Approach, Aditya V. Padaki, Maciej Zawodniok

Electrical and Computer Engineering Faculty Research & Creative Works

The passive backscatter technology is increasingly employed in wireless sensor network (WSN) applications. in contrast to existing technologies, it offers several advantages including a battery-less operation, extremely small-form factor, and low costs. Our previous works demonstrated that theoretically such backscatter-Based network outperforms existing solutions. in contrast, this paper presents a new time division multiple access (TDMA) based approach that considers a practical realization of the multi-hop framework. the capacity limits for the proposed scheme are evaluated for two frameworks - (a) single hop with direct backscatter signal and (b) a multi-hop transmission. an analytical comparison shows that the multi-hop transmission …

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Optimum Multi-Hop Transmission Strategies For Energy Constrained Wireless Sensor Networks, Jingxian Wu, Yahong Rosa Zheng Dec 2012

Optimum Multi-Hop Transmission Strategies For Energy Constrained Wireless Sensor Networks, Jingxian Wu, Yahong Rosa Zheng

Electrical and Computer Engineering Faculty Research & Creative Works

This paper presents optimum multi-hop transmission strategies (MHTS) for energy constrained wireless sensor networks (WSNs). Nodes in a multi-hop WSN need to transmit their own information and to relay each other's information to a base station (BS), and there are usually multiple available paths between a node and the BS. the optimum MHTS derived in this paper answers three questions: 1) how should a node divide its limited energy between the transmission of the self-information and the relay-information? 2) whether a single path or a combination of multiple paths should be used to route the information from a node to …

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Zheng Classification In Traditional Chinese Medicine Based On Modified Specular-Free Tongue Images, Ratchadaporn Kanawong, Tayo Obafemi-Ajayi, Jun Yu, Dong Xu, Shao Li, Ye Duan Dec 2012

Zheng Classification In Traditional Chinese Medicine Based On Modified Specular-Free Tongue Images, Ratchadaporn Kanawong, Tayo Obafemi-Ajayi, Jun Yu, Dong Xu, Shao Li, Ye Duan

Electrical and Computer Engineering Faculty Research & Creative Works

Traditional Chinese Medicine practitioners usually observe the color and coating of a patient's tongue to determine ZHENG (such as Cold or Hot ZHENG) and to diagnose different stomach disorders including gastritis. In our previous work, we explored new modalities for clinical characterization of ZHENG in gastritis patients via tongue image analysis using various supervised machine-learning algorithms. We proposed a system that learns from the clinical practitioner's subjective data how to classify a patients health status by extracting meaningful features from tongue images based on color-space models. In this paper, we propose an enhancement to the ZHENG classification system: a coating …

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Features For Automated Tongue Image Shape Classification, Tayo Obafemi-Ajayi, Ratchadaporn Kanawong, Dong Xu, Shao Li, Ye Duan Dec 2012

Features For Automated Tongue Image Shape Classification, Tayo Obafemi-Ajayi, Ratchadaporn Kanawong, Dong Xu, Shao Li, Ye Duan

Electrical and Computer Engineering Faculty Research & Creative Works

Inspection of the tongue is a key component in Traditional Chinese Medicine. Chinese medical practitioners diagnose the health status of a patient based on observation of the color, shape, and texture characteristics of the tongue. The condition of the tongue can objectively reflect the presence of certain diseases and aid in the differentiation of syndromes, prognosis of disease and establishment of treatment methods. Tongue shape is a very important feature in tongue diagnosis. A different tongue shape other than ellipse could indicate presence of certain pathologies. In this paper, we propose a novel set of features, based on shape geometry …

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Infrared Optical Path Adjustment Method For Common-Path Optical Coherence Tomography, Yanjun Li, Zhongdong Liu, Yinan Zhang, Hai Xiao Nov 2012

Infrared Optical Path Adjustment Method For Common-Path Optical Coherence Tomography, Yanjun Li, Zhongdong Liu, Yinan Zhang, Hai Xiao

Electrical and Computer Engineering Faculty Research & Creative Works

A new, common-path, in-axis concentric beam-splitting Michelson interferometer is demonstrated for optical coherence tomography (OCT), which can be used to perform high resolution cross-sectional in vivo and in situ imaging of biological tissues. a piece of glass tube with its inner diameter smaller than the beamwidth of the collimated light is used to split the light into a reference and sample beam. in order to obtain the optimal spectral interferogram of this OCT system, an infrared optical path adjustment method was introduced in this paper. © (2012) Trans Tech Publications, Switzerland.

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Assembled Singlemode And Graded Index Fibers Simulating Collimator For All Fiber Common-Path Optical Coherence Tomography, Yanjun Li, Jigui Zhu, Zhongdong Liu, Hai Xiao Nov 2012

Assembled Singlemode And Graded Index Fibers Simulating Collimator For All Fiber Common-Path Optical Coherence Tomography, Yanjun Li, Jigui Zhu, Zhongdong Liu, Hai Xiao

Electrical and Computer Engineering Faculty Research & Creative Works

A single mode fiber assembled with a specified length graded index multimode fiber as a collimator, which is used in common-path optical coherence tomography (CPOCT) is described in this paper. Compared with conventional collimator lens, this assembled fiber's structure possesses the advantages of small volume, easy to be fused or connected with other part of the CPOCT system. Furthermore, with this assembled structure and all fiber CPOCT system is constructed which has the potential to detect the internal bodily organs and tissues of human being. Numerical simulation and experiments are implemented to verify the effectiveness of this method. © (2012) …

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Power Distribution Network Reconfiguration For Bounded Transient Power Loss, Zhihao Li, Chenye Wu, Jiong Chen, Yiyu Shi, Jinjun Xiong, Amy Yuexuan Wang Nov 2012

Power Distribution Network Reconfiguration For Bounded Transient Power Loss, Zhihao Li, Chenye Wu, Jiong Chen, Yiyu Shi, Jinjun Xiong, Amy Yuexuan Wang

Electrical and Computer Engineering Faculty Research & Creative Works

We revisit the loss reduction problem for network reconfiguration in power distribution systems in this paper. Besides the conventional line power loss (LPL), in our model, we introduce a new concept - the transient power loss (TPL), which is mainly induced by the communication asynchronization and response delay. TPL is often overlooked in previous works because it's hard to measure in the conventional power networks. However, we can tackle this challenge in smart grid especially with the help of smart meter. in this paper, we propose a new heuristic greedy algorithm to achieve the minimal LPL with bounded TPL and …

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Model Based Diagnostics And Prognostics Of Three-Phase Induction Motor For Vapor Compressor Applications, Raja Sekhar Kraleti, Maciej Jan Zawodniok, Sarangapani Jagannathan Nov 2012

Model Based Diagnostics And Prognostics Of Three-Phase Induction Motor For Vapor Compressor Applications, Raja Sekhar Kraleti, Maciej Jan Zawodniok, Sarangapani Jagannathan

Electrical and Computer Engineering Faculty Research & Creative Works

In this work, a novel scheme for detection and prediction of multiple simultaneous faults in a three-phase induction motor in the context of vapor compression applications is presented. Induction motors used in vapor compression systems operate under variable speed conditions with variable frequencies. Such dynamic operating conditions may cause an occurrence of multiple, simultaneous faults including insulation degradation and a rotor bar breakage. These faults, when left undetected, lead to the failure of the motor and the entire vapor compression system. Hence, a condition monitoring of induction motors is essential. Conventional fault detection methods have various drawbacks including high implementation …

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A New Data Aggregation Scheme Via Adaptive Compression For Wireless Sensor Networks, Priya Kasirajan, Carl Larsen, S. Jagannathan Nov 2012

A New Data Aggregation Scheme Via Adaptive Compression For Wireless Sensor Networks, Priya Kasirajan, Carl Larsen, S. Jagannathan

Electrical and Computer Engineering Faculty Research & Creative Works

Data aggregation is necessary for extending the network lifetime of wireless sensor nodes with limited processing and power capabilities, since energy expended in transmitting a single data bit would be at least several orders of magnitude higher when compared to that needed for a 32-bit computation. Therefore, in this article, a novel nonlinear adaptive pulse coded modulation-Based compression (NADPCMC) scheme is proposed for data aggregation in a wireless sensor network (WSN). the NADPCMC comprises of two estimators-one at the source or transmitter and the second one at the destination node. the estimator at the source node approximates the data value …

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Reliable Power Delivery System Design For Three-Dimensional Integrated Circuits (3d Ics), Pei Wen Luo, Tao Wang, Chin Long Wey, Liang Chia Cheng, Bih Lan Sheu, Yiyu Shi Oct 2012

Reliable Power Delivery System Design For Three-Dimensional Integrated Circuits (3d Ics), Pei Wen Luo, Tao Wang, Chin Long Wey, Liang Chia Cheng, Bih Lan Sheu, Yiyu Shi

Electrical and Computer Engineering Faculty Research & Creative Works

Three-dimensional integrated circuits (3D ICs) have drawn groundswell of interest in both academia and industry in recent years. However, the power integrity of 3D ICs is threatened by the increased current density brought by vertical integration. to enhance reliability, the locations of power/ground through-silicon-vias (P/G TSVs), which are used to deliver power/ground signals to different layers, must be carefully placed to minimize IR-drop. However, the currents in 3D ICs are not deterministic and exhibit both spatial and temporal correlations. in view of this, we propose a correlation based heuristic algorithm for P/G TSV placement. Unlike most existing works, the proposed …

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Near-Field 3-D Synthetic Aperture Radar Imaging Via Compressed Sensing, Zengli Yang, Yahong Rosa Zheng Oct 2012

Near-Field 3-D Synthetic Aperture Radar Imaging Via Compressed Sensing, Zengli Yang, Yahong Rosa Zheng

Electrical and Computer Engineering Faculty Research & Creative Works

This paper successfully implements compressed sensing (CS) to a near-field wideband 3-D synthetic aperture radar (SAR) imaging system. SAR data are measured at a low percentage of random-selected positions on a uniform grid of planar aperture in the strip map mode. the near-field 3-D range migration algorithm (RMA) is used in combination with the CS principle to reconstruct the 3-D image via l 1 regularized least-square approach. Experiments were performed with Q-band stepped-frequency monostatic strip map SAR imaging system on a blue foam embedded with eight rubber pads and one copper square chip. the results of the experiments show near-field …

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On An Iterative Method For Basis Pursuit With Application To Echo Cancellation With Sparse Impulse Responses, Pratik Shah, Steven L. Grant, Jacob Benesty Oct 2012

On An Iterative Method For Basis Pursuit With Application To Echo Cancellation With Sparse Impulse Responses, Pratik Shah, Steven L. Grant, Jacob Benesty

Electrical and Computer Engineering Faculty Research & Creative Works

Basis pursuit has been shown to be an effective method of solving inverse problems with a small amount of data when the system to be determined has a sparse representation. Adaptive filters fall under this general category of problems. Here, we use the echo cancellation context to introduce a method of solving the basis pursuit problem with an iterative method based on the proportionate normalized affine projection algorithm (PAPA). Earlier, it has been shown that PAPA can be derived from a basis pursuit perspective. Here we refine the assumptions made in those derivations and show that an iterative form of …

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Effect Of Frequency Oversampling And Cascade Initialization On Permutation Control In Frequency Domain Bss, Christopher Osterwise, Steven L. Grant Oct 2012

Effect Of Frequency Oversampling And Cascade Initialization On Permutation Control In Frequency Domain Bss, Christopher Osterwise, Steven L. Grant

Electrical and Computer Engineering Faculty Research & Creative Works

This paper presents a new algorithm for addressing the permutation ambiguity in convolutive blind source separation. the proposed algorithm seeks to prevent permutations by frequency oversampling, and then exploiting the induced correlation between bins. Any remaining permutation is then corrected by beam pattern estimation. Cascade initialization is shown to improve system performance while decreasing processing time, while frequency oversampling is shown to increase performance with slight increases in computational time. the algorithm is proven robust against isotropic noise, producing an SIR improvement of 12.9 dB when the reverberation time is 260 ms, and the signals at the input are only …

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