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2014

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Articles 1201 - 1230 of 1516

Full-Text Articles in Electrical and Computer Engineering

A Kalman Filter With Individual Control Factors For Echo Cancellation, Constantin Paleologu, Jacob Benesty, Silviu Ciochinǎ, Steven L. Grant Jan 2014

A Kalman Filter With Individual Control Factors For Echo Cancellation, Constantin Paleologu, Jacob Benesty, Silviu Ciochinǎ, Steven L. Grant

Electrical and Computer Engineering Faculty Research & Creative Works

In echo cancellation, the main goal is to recover the near-end signal from the error signal of the adaptive filter, which identifies the echo path. In this context, the Kalman filter represents a very appealing choice, since its basic criterion follows the minimization of the system misalignment (instead of the usual error-based cost function). In this paper, we propose a Kalman filter with individual control factors, in terms of using a different level of uncertainty for each coefficient of the filter. As compared to the basic Kalman filter (which imposes the same uncertainty for all the coefficients of the impulse …

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On The Deployment Of On-Chip Noise Sensors, Tao Wang, Chun Zhang, Jinjun Xiong, Yiyu Shi Jan 2014

On The Deployment Of On-Chip Noise Sensors, Tao Wang, Chun Zhang, Jinjun Xiong, Yiyu Shi

Electrical and Computer Engineering Faculty Research & Creative Works

Runtime noise management systems can enforce power integrity without significantly increasing design margins. These systems typically respond to on-chip noise sensors to accurately capture voltage emergencies. Unfortunately, it remains an open problem in the literature how to optimally place a given number of noise sensors for best voltage emergency detection, or how to best set the threshold voltage for these sensors. In this paper, we formally define the problem of noise sensor placement along with a novel sensing quality metric to be maximized. We then put forward an efficient algorithm to solve it, which is proven to attain the best …

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Monolithic Three-Dimensional Integrated Circuits: Process And Design Implications, Hui Geng, Luke Maresca, Brian Cronquist, Zvi Or-Bach, Yiyu Shi Jan 2014

Monolithic Three-Dimensional Integrated Circuits: Process And Design Implications, Hui Geng, Luke Maresca, Brian Cronquist, Zvi Or-Bach, Yiyu Shi

Electrical and Computer Engineering Faculty Research & Creative Works

Conventional three-dimensional integrated circuits (3D ICs) stack multiple dies vertically for higher integration density, shorter wirelength, smaller footprint, faster speed and lower power consumption. However, the through-silicon-vias (TSVs) in die stacking based 3D ICs are large in size (>1um) and reduce the benefits that can be attained by the technology. In this paper, we will introduce a new fabrication process that facilitates monolithic 3D die integration and yields much smaller TSVs (~50 nm). We will also discuss various design benefits brought by the monolithic 3D IC technology.

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Linear Mimo Precoding In Jointly-Correlated Fading Multiple Access Channels With Finite Alphabet Signaling, Yongpeng Wu, Chao Kai Wen, Chengshan Xiao, Xiqi Gao, Robert Schober Jan 2014

Linear Mimo Precoding In Jointly-Correlated Fading Multiple Access Channels With Finite Alphabet Signaling, Yongpeng Wu, Chao Kai Wen, Chengshan Xiao, Xiqi Gao, Robert Schober

Electrical and Computer Engineering Faculty Research & Creative Works

In this paper, we investigate the design of linear precoders for multiple-input multiple-output (MIMO) multiple access channels (MAC). We assume that statistical channel state information (CSI) is available at the transmitters and consider the problem under the practical finite alphabet input assumption. First, we derive an asymptotic (in the large-system limit) weighted sum rate (WSR) expression for the MIMO MAC with finite alphabet inputs and general jointly correlated fading. Subsequently, we obtain necessary conditions for linear precoders maximizing the asymptotic WSR and propose an iterative algorithm for determining the precoders of all users. In the proposed algorithm, the search space …

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Multibit Retention Registers For Power Gated Designs: Concept, Design, And Deployment, Yu Guang Chen, Hui Geng, Kuan Yu Lai, Yiyu Shi, Shih Chieh Chang Jan 2014

Multibit Retention Registers For Power Gated Designs: Concept, Design, And Deployment, Yu Guang Chen, Hui Geng, Kuan Yu Lai, Yiyu Shi, Shih Chieh Chang

Electrical and Computer Engineering Faculty Research & Creative Works

Retention registers have been widely used in power gated designs to store data during sleep mode. However, their excessive area and leakage power render it imperative to minimize the total retention storage size. The current industry practice replaces all registers with single bit retention ones, which significantly limits the design freedom and yields suboptimal designs. Toward this, for the first time in the literature, we propose the concept and the design of multibit retention registers, with which only selected registers need to be replaced. The technique can significantly reduce the number of bits that need to be stored and thus …

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Yield And Timing Constrained Spare Tsv Assignment For Three-Dimensional Integrated Circuits, Yu Guang Chen, Kuan Yu Lai, Ming Chao Lee, Yiyu Shi, Wing Kai Hon Jan 2014

Yield And Timing Constrained Spare Tsv Assignment For Three-Dimensional Integrated Circuits, Yu Guang Chen, Kuan Yu Lai, Ming Chao Lee, Yiyu Shi, Wing Kai Hon

Electrical and Computer Engineering Faculty Research & Creative Works

Through Silicon Via (TSV) is a critical enabling technique in three-dimensional integrated circuits (3D ICs). However, it may suffer from many reliability issues. Various fault-tolerance mechanisms have been proposed in literature to improve yield, at the cost of significant area overhead. In this paper, we focus on the structure that uses one spare TSV for a group of original TSVs and study the optimal assignment of spare TSVs under yield and timing constraints to minimize the total area overhead. We show that such problem can be modeled through constrained graph decomposition. An efficient heuristic is further developed to address this …

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

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

Electrical and Computer Engineering Faculty Research & Creative Works

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

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Near Optimal Boundary Control Of Distributed Parameter Systems Modeled As Parabolic Pdes By Using Finite Difference Neural Network Approximation, Behzad Talaei, Hao Xu, S. Jagannathan Jan 2014

Near Optimal Boundary Control Of Distributed Parameter Systems Modeled As Parabolic Pdes By Using Finite Difference Neural Network Approximation, Behzad Talaei, Hao Xu, S. Jagannathan

Electrical and Computer Engineering Faculty Research & Creative Works

This paper develops a novel neural network (NN) based near optimal boundary control scheme for distributed parameter systems (DPS) governed by semi linear parabolic partial differential equations (PDE) in the presence of control constraints and unknown system dynamics. First, finite difference method (FDM) is utilized to develop a reduced order system which represents the discretized dynamics of PDE system. Subsequently, a near optimal control scheme is proposed for the discretized system by using NN based approximate dynamic programming (ADP). To relax the requirement of system dynamics, a NN identifier is utilized. Moreover, a second NN is proposed to estimate a …

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

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

Electrical and Computer Engineering Faculty Research & Creative Works

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

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A Model-Based Fault Detection And Prognostics Scheme For Takagi-Sugeno Fuzzy Systems, Balaje T. Thumati, Miles A. Feinstein, S. Jagannathan Jan 2014

A Model-Based Fault Detection And Prognostics Scheme For Takagi-Sugeno Fuzzy Systems, Balaje T. Thumati, Miles A. Feinstein, S. Jagannathan

Electrical and Computer Engineering Faculty Research & Creative Works

In this paper, a novel model-based fault detection (FD) and prediction scheme is developed for a class of Takagi-Sugeno (T-S) fuzzy systems. Unlike other FD schemes, in the proposed design, an FD observer with online fault learning capability is utilized to generate a residual which is obtained by comparing the system output with respect to the observer output. A fault is declared active if the generated residual exceeds an a priori chosen threshold. Subsequently, the fault magnitude is estimated online by using a suitable parameter update law. Upon detection, the online estimate of the fault magnitude is used in a …

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

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

Electrical and Computer Engineering Faculty Research & Creative Works

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

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

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

Electrical and Computer Engineering Faculty Research & Creative Works

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

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Ambiguity Group Based Location Recognition For Multiple Power Line Outages In Smart Grids, Jie Wu, Jinjun Xiong, Yiyu Shi Jan 2014

Ambiguity Group Based Location Recognition For Multiple Power Line Outages In Smart Grids, Jie Wu, Jinjun Xiong, Yiyu Shi

Electrical and Computer Engineering Faculty Research & Creative Works

The efficient location recognition of multiple outage lines is critical to not only cascading failure elimination but also repair cost reduction. Most of existing methods, however, fail to handle location recognition well. This failure typically occurs because the methods cannot overcome three challenges: the very limited number of Phasor Measurement Units (PMUs), the high computational complexity, and the possibility of concurrent multiple outage lines. This paper presents an efficient algorithm inspired by the ambiguity group theory to recognize the most likely outage line locations with limited PMUs. Using IEEE 14-, 57-, and 118-bus system, the experimental study demonstrates that the …

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

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

Electrical and Computer Engineering Faculty Research & Creative Works

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

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

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

Electrical and Computer Engineering Faculty Research & Creative Works

This paper focuses on neural network (NN) based optimal control of nonlinear continuous-time systems in strict-feedback form when the system dynamics are known by using an adaptive backstepping approach. A single NN-based adaptive approach is designed to learn the solution of the infinite horizon continuous-time Hamilton-Jacobi-Bellman (HJB) equation while the corresponding optimal control input that minimizes the HJB equation is calculated in a forward-in-time manner without using value and policy iterations. First, the optimal control problem is solved for a generic multi-input and multi-output nonlinear system with a state feedback approach. Then the approach is extended to a single-input and …

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

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

Electrical and Computer Engineering Faculty Research & Creative Works

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

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Soft-Decision Feedback Turbo Equalization For Ldpc-Coded Mimo Underwater Acoustic Communications, Amirhossein Rafati, Huang Lou, Chengshan Xiao Jan 2014

Soft-Decision Feedback Turbo Equalization For Ldpc-Coded Mimo Underwater Acoustic Communications, Amirhossein Rafati, Huang Lou, Chengshan Xiao

Electrical and Computer Engineering Faculty Research & Creative Works

In this paper, a low-complexity turbo-detection scheme is proposed for single-carrier multiple-input-multiple-output (MIMO) underwater acoustic (UWA) communication systems that employ low-density parity-check (LDPC) channel coding. The proposed iterative soft-decision feedback equalization (SDFE) algorithm offers a novel approach to combat error propagation by utilizing the past soft decisions to mitigate InterSymbol interference. In addition, we utilize an iterative data detection and channel estimation scheme to reduce the pilot overhead used in the data communication system. Performance of the proposed detection scheme is demonstrated through extensive communication data from two undersea experiments. The results show that the proposed SDFE algorithm provides robust …

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

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

Electrical and Computer Engineering Faculty Research & Creative Works

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

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

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

Electrical and Computer Engineering Faculty Research & Creative Works

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

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Low Complexity Detection Algorithm For Under-Determined Mimo Systems, Chen Qian, Jingxian Wu, Yahong Rosa Zheng, Zhaocheng Wang Jan 2014

Low Complexity Detection Algorithm For Under-Determined Mimo Systems, Chen Qian, Jingxian Wu, Yahong Rosa Zheng, Zhaocheng Wang

Electrical and Computer Engineering Faculty Research & Creative Works

A low complexity detection algorithm based on list sphere decoding (LSD) is proposed for under-determined multiple-input multiple-output (UD-MIMO) systems with N transmit antennas and M < N receive antennas. The proposed algorithm utilizes the unique structure of UD-MIMO systems by dividing the N detection layers into two groups. Group 1 contains layers 1 to M that have similar structures as a symmetric MIMO system; while Group 2 contains layers M + 1 to N that contribute to the rank deficiency of the channel Gram matrix. Tree search algorithms are used for both groups, but with different search radii. A new method is proposed to adaptively adjust the tree search radius of Group 2 based on the statistical properties of the received signals. The employment of the adaptive tree search can significantly reduce the computational complexity. Simulation results show that the proposed algorithm can reduce the complexity by one orders of magnitude with less than 0.01 dB degradation in the Bit-Error-Rate (BER) performance. © 2014 IEEE.

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

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

Electrical and Computer Engineering Faculty Research & Creative Works

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

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Neural Network-Based Finite-Horizon Approximately Optimal Control Of Uncertain Affine Nonlinear Continuous-Time Systems, Hao Xu, Qiming Zhao, Travis Dierks, S. Jagannathan Jan 2014

Neural Network-Based Finite-Horizon Approximately Optimal Control Of Uncertain Affine Nonlinear Continuous-Time Systems, Hao Xu, Qiming Zhao, Travis Dierks, S. Jagannathan

Electrical and Computer Engineering Faculty Research & Creative Works

This paper develops a novel neural network (NN) based finite-horizon approximate optimal control of nonlinear continuous-time systems in affine form when the system dynamics are complete unknown. First an online NN identifier is proposed to learn the dynamics of the nonlinear continuous-time system. Subsequently, a second NN is utilized to learn the time-varying solution, or referred to as value function, of the Hamilton-Jacobi-Bellman (HJB) equation in an online and forward in time manner. Then, by using the estimated time-varying value function from the second NN and control coefficient matrix from the NN identifier, an approximate optimal control input is computed. …

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

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

Electrical and Computer Engineering Faculty Research & Creative Works

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

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Phasor Measurement Unit Placement For Identifying Power Line Outages In Wide-Area Transmission System Monitoring, Hao Zhu, Yiyu Shi Jan 2014

Phasor Measurement Unit Placement For Identifying Power Line Outages In Wide-Area Transmission System Monitoring, Hao Zhu, Yiyu Shi

Electrical and Computer Engineering Faculty Research & Creative Works

Phasor measurement units (PMUs) are widely recognized to be instrumental for enhancing the power system situational awareness - a key step toward the future power grid. With limited PMU resources and high installation costs, it is of great importance to develop strategic PMU deployment methods. This paper focuses on optimally selecting PMU locations for monitoring transmission line status across the wide-area grid. To bypass the combinatorial search involved, a linear programming reformulation is first developed to provide an upper bound estimate for the global optimum. Furthermore, a greedy heuristic method is adopted with the complexity only linearly in the number …

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

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

Electrical and Computer Engineering Faculty Research & Creative Works

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

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

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

Electrical and Computer Engineering Faculty Research & Creative Works

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

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

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

Electrical and Computer Engineering Faculty Research & Creative Works

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

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Multi-Finger Mosfet Low Noise Amplifier Performance Analysis, Xiaomeng Zhang Jan 2014

Multi-Finger Mosfet Low Noise Amplifier Performance Analysis, Xiaomeng Zhang

Browse all Theses and Dissertations

Multi-finger layout technique has been extensively used in Nano-scale CMOS circuit design due to the increased circuit performance compared to a single finger layout. However choosing a finger width (W_f) and number of fingers (N_f) to optimize circuit performance is a challenging problem. In this thesis, the performances of 2.4GHz and 6.0GHz single ended low noise amplifiers (LNA) with fixed total transistor widths in 90nm CMOS technology are analyzed as function of number of fingers, bias voltage (V_bias) and channel length (L). The results show that the drain to source current, transconductance and effective gate capacitance increase with increasing number …

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Visible-Light Photocatalyzed Cross-Linking Of Diacetylene Ligands By Quantum Dots To Improve Their Aqueous Colloidal Stability, Marion G. Götz, Hiroko Takeuchi, Matthew J. Goldfogel, Julia M. Warren, Brandon D. Fennel, Colin D. Heyes Jan 2014

Visible-Light Photocatalyzed Cross-Linking Of Diacetylene Ligands By Quantum Dots To Improve Their Aqueous Colloidal Stability, Marion G. Götz, Hiroko Takeuchi, Matthew J. Goldfogel, Julia M. Warren, Brandon D. Fennel, Colin D. Heyes

Chemistry & Biochemistry Faculty Publications and Presentations

Ligand cross-linking is known to improve the colloidal stability of nanoparticles, particularly in aqueous solutions. However, most cross-linking is performed chemically, in which it is difficult to limit interparticle cross-linking, unless performed at low concentrations. Photochemical cross-linking is a promising approach but usually requires ultraviolet (UV) light to initiate. Using such high-energy photons can be harmful to systems in which the ligand–nanoparticle bond is fairly weak, as is the case for the commonly used semiconductor quantum dots (QDs). Here, we introduce a novel approach to cross-link thiolated ligands on QDs by utilizing the photocatalytic activity of QDs upon absorbing visible …

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Performance-Limiting Factors For Gaas-Based Single Nanowire Photovoltaics, Xufeng Wang, Mohammad Ryyan Khan, Mark Lundstrom, Peter Bermel Jan 2014

Performance-Limiting Factors For Gaas-Based Single Nanowire Photovoltaics, Xufeng Wang, Mohammad Ryyan Khan, Mark Lundstrom, Peter Bermel

Department of Electrical and Computer Engineering Faculty Publications

GaAs nanowires (NWs) offer the possibility of decoupling light absorption from charge transport for high-performance photovoltaic (PV) devices. However, it is still an open question as to whether these devices can exceed the Shockley-Queisser efficiency limit for single-junction PV. In this work, single standing GaAs-based nanowire solar cells in both radial and vertical junction configurations is analyzed and compared to a planar thin-film design. By using a self-consistent, electrical-optically coupled 3D simulator, we show the design principles for nanowire and planar solar cells are significantly different; nanowire solar cells are vulnerable to surface and contact recombination, while planar solar cells …

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