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Electrical and Computer Engineering Faculty Research & Creative Works

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Articles 2041 - 2070 of 3518

Full-Text Articles in Engineering

Channel Estimation For Ofdm Systems In The Presence Of Carrier Frequency Offset And Phase Noise, Jun Tao, Jingxian Wu, Chengshan Xiao May 2008

Channel Estimation For Ofdm Systems In The Presence Of Carrier Frequency Offset And Phase Noise, Jun Tao, Jingxian Wu, Chengshan Xiao

Electrical and Computer Engineering Faculty Research & Creative Works

Channel estimation for orthogonal frequency division multiplexing (OFDM) system at the presence of carrier frequency offset (CFO) and phase noise is discussed in this paper. A CFO estimation algorithm is developed by exploiting the time-frequency structure of training symbols, and it provides a very accurate estimation of CFO at the presence of both unknown frequency selective fading and phase noise. Based on the estimated CFO, the phase noise and frequency selective fading are jointly estimated by employing the maximum a posteriori (MAP) criterion. Specifically, the fading channel is estimated in the form of frequency domain channel transfer function (CTF). The …

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Universal Electric And Magnetic Field Analyzer System, Yong Cheh Ho, David Pommerenke, Tun Li May 2008

Universal Electric And Magnetic Field Analyzer System, Yong Cheh Ho, David Pommerenke, Tun Li

Electrical and Computer Engineering Faculty Research & Creative Works

Near-field probing is often used to determine the sources and coupling paths of an electromagnetic interference problem above a printed circuit board or integrated circuits chip. A wideband universal field analyzer was developed in order to measure circularly and linearly polarized magnetic fields and total electric field in a rapid sequence using a single probe design.

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Zeolite Thin Film-Coated Long Period Fiber Grating Sensor For Measuring Trace Chemical, Jian Zhang, Xiling Tang, Junhang Dong, Tao Wei, Hai Xiao May 2008

Zeolite Thin Film-Coated Long Period Fiber Grating Sensor For Measuring Trace Chemical, Jian Zhang, Xiling Tang, Junhang Dong, Tao Wei, Hai Xiao

Electrical and Computer Engineering Faculty Research & Creative Works

This paper reports the development of a new zeolite thin film-coated long period fiber grating (LPFG) sensor for direct measurement of trace organic vapors. The sensor was fabricated by growing pure silica MFI-type zeolite thin film on the optical fiber grating by in situ hydrothermal crystallization. The sensor measures chemical vapor concentration by monitoring the molecular adsorption-induced shift of LPFG resonant wavelength in near infrared (IR) region. Upon loading analyte molecules, the zeolite's refractive index changes in the close vicinity of the fiber index where the LPFG has a large response to achieve high sensitivity.

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A Novel 24 Ghz One-Shot, Rapid And Portable Microwave Imaging System, Mohammad Tayeb Ahmad Ghasr, Mohamed A. Abou-Khousa, Sergey Kharkovsky, R. Zoughi, David Pommerenke May 2008

A Novel 24 Ghz One-Shot, Rapid And Portable Microwave Imaging System, Mohammad Tayeb Ahmad Ghasr, Mohamed A. Abou-Khousa, Sergey Kharkovsky, R. Zoughi, David Pommerenke

Electrical and Computer Engineering Faculty Research & Creative Works

Development of microwave and millimeter wave imaging systems has received significant attention in the past decade. Signals at these frequencies penetrate inside of dielectric materials and have relatively small wavelengths. Thus, imaging systems at these frequencies can produce images of the dielectric and geometrical distributions of objects. Although there are many different approaches for imaging at these frequencies, they each have their respective advantageous and limiting features (hardware, reconstruction algorithms). One method involves electronically scanning a given spatial domain while recording the coherent scattered field distribution from an object. Consequently, different reconstruction or imaging techniques may be used to produce …

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A Stabilizing, High-Performance Controller For Input Series-Output Parallel Converters, Jonathan W. Kimball, Joseph T. Mossoba, Philip T. Krein May 2008

A Stabilizing, High-Performance Controller For Input Series-Output Parallel Converters, Jonathan W. Kimball, Joseph T. Mossoba, Philip T. Krein

Electrical and Computer Engineering Faculty Research & Creative Works

A form of sensorless current mode (SCM) control stabilizes sharing in multiphase input-series-output-parallel (ISOP) dc-dc converter topologies. Previously, ISOP converters have been proposed to reduce the voltage and current ratings of switching devices. Since the inputs are all connected in series, each phase need only be rated for a fraction of the total input voltage. Voltage and current sharing are key - if there is any phase-to-phase imbalance, the system benefits are substantially reduced. In the present work, a simple SCM controller is shown to guarantee stable sharing. Each phase acts independently on the same output reference and desired input …

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An Experimental Investigation Of Higher Order Mode Suppression In Tem Cells, Shaowei Deng, David Pommerenke, Todd H. Hubing, Dongshik Shin May 2008

An Experimental Investigation Of Higher Order Mode Suppression In Tem Cells, Shaowei Deng, David Pommerenke, Todd H. Hubing, Dongshik Shin

Electrical and Computer Engineering Faculty Research & Creative Works

Transverse electromagnetic (TEM) cells can be used to evaluate the electric and magnetic fields coupling from integrated circuits (ICs). The propagation and reflection of higher order modes in the cells limits the bandwidth of TEM cells. This paper investigates several methods for suppressing higher order modes in TEM cells in order to extend the applicable frequency range without changing the test topology. Numerical models and measurements of a modified TEM cell demonstrate how higher order mode suppression techniques can extend the useful frequency range of a TEM cell for IC measurements from 1 to 2.5 GHz.

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Clustering Of High-Dimensional Gene Expression Data With Feature Filtering Methods And Diffusion Maps, Rui Xu, Steven Damelin, Boaz Nadler, Donald C. Wunsch May 2008

Clustering Of High-Dimensional Gene Expression Data With Feature Filtering Methods And Diffusion Maps, Rui Xu, Steven Damelin, Boaz Nadler, Donald C. Wunsch

Electrical and Computer Engineering Faculty Research & Creative Works

The importance of gene expression data in cancer diagnosis and treatment by now has been widely recognized by cancer researchers in recent years. However, one of the major challenges in the computational analysis of such data is the curse of dimensionality, due to the overwhelming number of measures of gene expression levels versus the small number of samples. Here, we use a two-step method to reduce the dimension of gene expression data. At first, we extract a subset of genes based on the statistical characteristics of their corresponding gene expression measurements. For further dimensionality reduction, we then apply diffusion maps, …

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Multimodal Solution For A Rectangular Waveguide Radiating Into A Multilayered Dielectric Structure And Its Application For Dielectric Property And Thickness Evaluation, Mohammad Tayeb Ahmad Ghasr, R. Zoughi May 2008

Multimodal Solution For A Rectangular Waveguide Radiating Into A Multilayered Dielectric Structure And Its Application For Dielectric Property And Thickness Evaluation, Mohammad Tayeb Ahmad Ghasr, R. Zoughi

Electrical and Computer Engineering Faculty Research & Creative Works

Open-ended rectangular waveguides are widely used for microwave and millimeter wave nondestructive testing applications. Applications have included detecting disbonds and delaminations in multilayered composite structures, thickness evaluation of dielectric sheets and coatings on metal substrates, etc. When inspecting a complex multilayered composite structure, made of generally lossy dielectric layers with arbitrary thicknesses and backing, the dielectric properties of a particular layer within the structure is of particular interest, such being health monitoring of structures such as radomes. The same is also true where one may be interested in the thickness or more importantly thickness variation of a particular layer within …

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Improved Frequency-Domain Channel Estimation For Fast Time-Varying Mimo-Scfde Channels, Y. Rosa Zheng, Jian Zhang May 2008

Improved Frequency-Domain Channel Estimation For Fast Time-Varying Mimo-Scfde Channels, Y. Rosa Zheng, Jian Zhang

Electrical and Computer Engineering Faculty Research & Creative Works

A frequency-domain channel estimation method is proposed for time-varying multiple-input multiple output (MIMO) single-carrier frequency-domain equalization (SC-FDE). The proposed method uses frequency-domain interpolation to obtain channel frequency responses of data blocks from estimated responses of two adjacent pilot blocks. It takes the channel temporal-spatial correlation into account to achieve minimum mean squared error (MMSE) estimation, thus improving the accuracy and effectiveness in high Doppler scenarios. The simulation results of the bit error rate (BER) performances show that the proposed method works well for fast time-varying channels with Doppler spread as high as 300 Hz while maintaining over 70% data efficiency.

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Potential Application Of The Modulated Scatterer Technique To Multilayered Material Evaluation And Health Monitoring, Kristen M. Munoz, Amy K. Perrey, R. Zoughi May 2008

Potential Application Of The Modulated Scatterer Technique To Multilayered Material Evaluation And Health Monitoring, Kristen M. Munoz, Amy K. Perrey, R. Zoughi

Electrical and Computer Engineering Faculty Research & Creative Works

Modulated scatterer technique (MST) is based on illuminating a small antenna, usually a dipole, loaded with a PIN diode, with an electromagnetic wave. The scattered (or reflected) wave from the probe may then be used to determine dielectric properties of the material in which the probe is located or embedded. The PIN diode is turned "on" and "off" which not only changes the impedance of the probe, but also modulates (with the same rate) the reflection from the probe. A major challenge associated with MST is detecting and distinguishing the desired probe response in the ever-present reflections from surrounding structures …

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Using Tem Cell Measurements To Estimate The Maximum Radiation From Pcbs With Cables Due To Magnetic Field Coupling, Shaowei Deng, Todd H. Hubing, Daryl G. Beetner May 2008

Using Tem Cell Measurements To Estimate The Maximum Radiation From Pcbs With Cables Due To Magnetic Field Coupling, Shaowei Deng, Todd H. Hubing, Daryl G. Beetner

Electrical and Computer Engineering Faculty Research & Creative Works

Common-mode currents can be induced on cables attached to printed circuit boards (PCBs) due to electric and magnetic field coupling. This paper describes a technique for using transverse electromagnetic (TEM) cell measurements to obtain an effective common-mode voltage (or magnetic moment) that quantifies the ability of traces and integrated circuits on PCBs to drive common-mode currents onto cables due to magnetic field coupling. This equivalent common-mode voltage can be used to reduce the complexity of full-wave models that calculate the radiated emissions from a system containing the board. It can also be used without full-wave modeling to provide a …

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A Variable Partitioning Strategy For The Multirate Method In Power Systems, Jingjia Chen, Mariesa Crow May 2008

A Variable Partitioning Strategy For The Multirate Method In Power Systems, Jingjia Chen, Mariesa Crow

Electrical and Computer Engineering Faculty Research & Creative Works

An application of the multirate method to differential and algebraic equations (DAEs) is discussed in this paper. Based on the specific formulation of the power systems algebraic equations, an effective algebraic variable partitioning strategy is developed and implemented. The application of the partitioning strategy to an example power system provides validation of the proposed partitioning strategy in terms of speed-up and accuracy.

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Design And Implementation Of Fpga Configuration Logic Block Using Asynchronous Static Ncl, Waleed K. Al-Assadi, T. Tammina, Scott C. Smith, Indira P. Dugganapally Apr 2008

Design And Implementation Of Fpga Configuration Logic Block Using Asynchronous Static Ncl, Waleed K. Al-Assadi, T. Tammina, Scott C. Smith, Indira P. Dugganapally

Electrical and Computer Engineering Faculty Research & Creative Works

This paper proposes the design of a FPGA configurable logic block (CLB) using asynchronous static NULL convention logic (NCL) Library. The proposed design uses three static LUT's for implementing NCL logic functions. Each LUT can be configured to function as any one of the 27 fundamental NCL Static gates. The proposed CLB supports 10 inputs and three different outputs, each with resettable and inverting variations. The CLB has two modes: Configuration mode and operation mode. The static NCL FPGA CLB is simulated at the transistor level using the 1.8 V, 180 nm TSMC CMOS process.

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Missouri S&T Mote-Based Demonstration Of Energy Monitoring Solution For Network Enabled Manufacturing Using Wireless Sensor Networks (Wsn), James W. Fonda, Maciej Jan Zawodniok, Al Salour, Jagannathan Sarangapani, Donald Miller Apr 2008

Missouri S&T Mote-Based Demonstration Of Energy Monitoring Solution For Network Enabled Manufacturing Using Wireless Sensor Networks (Wsn), James W. Fonda, Maciej Jan Zawodniok, Al Salour, Jagannathan Sarangapani, Donald Miller

Electrical and Computer Engineering Faculty Research & Creative Works

In this work, an inexpensive electric utilities monitoring solution using wireless sensor networks is demonstrated that can easily be installed, deployed, maintained and eliminate unnecessary energy costs and effort. The monitoring solution is designed to support network enabled manufacturing (NEM) program using Missouri University of Science and Technology (MST), formerly the University of Missouri-Rolla (UMR), motes.

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Modeling Of Substrate Noise Effects In Dynamic Cmos Circuits, Waleed K. Al-Assadi, S. Burugapalli, Sagar R. Gosavi Apr 2008

Modeling Of Substrate Noise Effects In Dynamic Cmos Circuits, Waleed K. Al-Assadi, S. Burugapalli, Sagar R. Gosavi

Electrical and Computer Engineering Faculty Research & Creative Works

The decrease in the feature size has led to the integration of both digital and analog circuits on the same silicon die which has led to many crosstalk issues. The crosstalk due to the substrate interactions also plagiarizes complete digital systems. This paper lays emphasis on this fact and because of the vulnerability of dynamic CMOS circuits to noise; a brief study of the effects of substrate variations on the performance of the dynamic CMOS circuits is carried out in this paper. The effects of substrate noise at very high frequencies (above 10 GHz) are also depicted in this paper. …

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Modeling The Cellular Level Of Natural Sensing With The Functional Basis For The Design Of Biomimetic Sensor Technology, Jacquelyn K. Stroble, Robert B. Stone, Daniel A. Mcadams, L. H. Shu, Steve Eugene Watkins Apr 2008

Modeling The Cellular Level Of Natural Sensing With The Functional Basis For The Design Of Biomimetic Sensor Technology, Jacquelyn K. Stroble, Robert B. Stone, Daniel A. Mcadams, L. H. Shu, Steve Eugene Watkins

Electrical and Computer Engineering Faculty Research & Creative Works

After surveying biology for natural sensing solutions six main types of extraneous sensing were identified across the biological kingdoms. Natural sensing happens at the cellular level with receptor cells that respond to photo, chemo, eletro, mechano, thermo and magnetoreceptor-type stimuli. At the highest level, all natural sensing systems have the same reaction sequence to stimuli: perception, transduction, and response. This research is exploring methods for knowledge transfer between the biological and engineering domains. With the use of the Functional Basis, a well-defined modeling language, the ingenuity of natural sensing can be captured through functional models and crossed over into the …

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Performance Of A Quaternary Logic Design, M. Dornajafi, B. Cooper, Steve Eugene Watkins, M. Ryan Bales Apr 2008

Performance Of A Quaternary Logic Design, M. Dornajafi, B. Cooper, Steve Eugene Watkins, M. Ryan Bales

Electrical and Computer Engineering Faculty Research & Creative Works

This paper analyzes the performance of a quaternary logic circuit and its components. The multi-valued logic design consisting of two drivers and a transistor matrix is simulated using Mentor Graphic software. Functional operation of the circuit is shown and propagation delay and power consumption are determined. The design is dependent on the voltage values for the multi-valued logic. Three logic cases are investigated. The performance of the logic circuit as a quaternary difference calculator is described.

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Secured Hardware Design - An Overview, S. Burugapalli, Waleed K. Al-Assadi Apr 2008

Secured Hardware Design - An Overview, S. Burugapalli, Waleed K. Al-Assadi

Electrical and Computer Engineering Faculty Research & Creative Works

Security is a prime concern in the design of a wide variety of embedded systems and security processors. So the customer security devices such as smart cards and security processors are prone to attack and there are on going research to protect these devices from attackers who intend to extract key information from these devices. Also an active attacker can induce errors during computation and exploit the faulty result to extract the key information embedded in the processor. Due to the design time issues weakness in the design is often revealed in the manufactured chips. Also because the post- manufacture …

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Design And Implementation Of Fpga Configuration Logic Block Using Asynchronous Semi-Static Ncl Circuits, Indira P. Dugganapally, Waleed K. Al-Assadi, Vijay Pillai, Scott C. Smith Apr 2008

Design And Implementation Of Fpga Configuration Logic Block Using Asynchronous Semi-Static Ncl Circuits, Indira P. Dugganapally, Waleed K. Al-Assadi, Vijay Pillai, Scott C. Smith

Electrical and Computer Engineering Faculty Research & Creative Works

This paper proposes the design of a FPGA configurable logic block (CLB) using asynchronous semi-static NULL convention logic (NCL) Library. The proposed design uses three semi-static LLT's for implementing NCL logic functions. Each LLT can be configured to function as any one of the 27 fundamental NCL Semi-Static gates. The proposed CLB supports 10 inputs and three different outputs, each with resettable and inverting variations. The CLB has two modes: Configuration mode and Operation mode. The Static NCL FPGA CLB is simulated at the transistor level using the 1.8 V, 180 nm TSMC CMOS process.

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Design And Fpga Prototyping Of A Flood Prediction System, Sandeep Gandla, Waleed K. Al-Assadi, Sahra Sedigh, Raghu A. R. Rao Apr 2008

Design And Fpga Prototyping Of A Flood Prediction System, Sandeep Gandla, Waleed K. Al-Assadi, Sahra Sedigh, Raghu A. R. Rao

Electrical and Computer Engineering Faculty Research & Creative Works

This paper explains the chip design of a flood prediction system based on piezoelectric pressure sensors, and its FPGA prototyping. The sensors are placed at different water levels and can dependably predict the occurrence of a flood. The main criteria considered in design of the system are low cost, low power consumption, ease of installation, autonomy, reliability, and most importantly, provision of early alerts. Predicting the flood before its actual occurrence can buy sufficient time for residents to evacuate nearby areas, preventing loss of life and property. The design has been prototyped on Altera's Cyclone DE2 FPGA board.

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Testing Of Asynchronous Null Conventional Logic (Ncl) Circuits, Sindhu Kakarla, Waleed K. Al-Assadi Apr 2008

Testing Of Asynchronous Null Conventional Logic (Ncl) Circuits, Sindhu Kakarla, Waleed K. Al-Assadi

Electrical and Computer Engineering Faculty Research & Creative Works

Due to the absence of a global clock and presence of more state holding elements that synchronize the control and data paths, conventional automatic test pattern generation (ATPG) algorithms would fail when applied to asynchronous circuits, leading to poor fault coverage. This paper focuses on design for test (DFT) techniques aimed at making asynchronous NCL designs testable using existing DFT CAD tools with reasonable gate overhead, by enhancing controllability of feedback nets and observability for fault sites that are flagged unobservable. The proposed approach performs scan and test points insertion on NCL designs using custom ATPG library. The approach has …

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A Fast And Efficient Frequency-Domain Method For Convolutive Blind Source Separation, Peng Xie, Steven L. Grant Apr 2008

A Fast And Efficient Frequency-Domain Method For Convolutive Blind Source Separation, Peng Xie, Steven L. Grant

Electrical and Computer Engineering Faculty Research & Creative Works

In this paper, the problem of blind separation of a convolutive mixture of audio signals is considered. A fast and efficient frequency-domain blind source separation (BSS) method using Independent component analysis (ICA) is investigated. The main difficulties of this approach lie in the so called permutation and amplitude problems. In order to solve the permutation ambiguity, the final value of the ICA derived separation matrix of one frequency bin, is used to initialize the ICA iterations in the next frequency bin. The amplitude problem is addressed by utilizing the elements in the inverse of the separation matrix. Experimental results demonstrate …

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Dual-Function Neuron-Based External Controller For A Static Var Compensator, Ganesh K. Venayagamoorthy, Sandhya R. Jetti Apr 2008

Dual-Function Neuron-Based External Controller For A Static Var Compensator, Ganesh K. Venayagamoorthy, Sandhya R. Jetti

Electrical and Computer Engineering Faculty Research & Creative Works

The use of wide-area measurements for power system stabilization has recently been given a lot of attention by researchers and the power industry to avoid cascading failures and blackouts, such as the one in North America in August 2003. This paper presents the design of a nonlinear external damping controller based on wide-area measurements as inputs to a single dual-function neuron (DFN)-based controller. This DFN controller is specifically designed to enhance the damping characteristics of a power system over a wide range of operating conditions using an existing static var compensator (SVC) installation. The major advantage of the DFN controller …

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Further Results On Frequency-Domain Channel Equalization For Single Carrier Underwater Acoustic Communications, Y. Rosa Zheng, Chengshan Xiao, Xin Liu, Wen-Bin Yang, T. C. Yang Apr 2008

Further Results On Frequency-Domain Channel Equalization For Single Carrier Underwater Acoustic Communications, Y. Rosa Zheng, Chengshan Xiao, Xin Liu, Wen-Bin Yang, T. C. Yang

Electrical and Computer Engineering Faculty Research & Creative Works

A frequency-domain channel equalization and phase correction method was proposed in a previous work published in Oceans'07 conference, in which 10^-4 BER performance was presented for fixed-to-fixed source/receiver channels. The method is improved by using minimum mean square error (MMSE) estimation in channel updates rather than least squares estimation. It is applied to moving-to-fixed channels in the AUVFest'07 ocean experiment where single-carrier wideband transmission was employed with quadrature phase shift keying modulation. The moving source channels exhibit higher Doppler shift and larger Doppler drift than the fixed-to-fixed channels. Therefore, the number of symbols required for initial phase estimation is increased …

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Uav Autopilot Integration And Testing, David Erdos, Steve Eugene Watkins Apr 2008

Uav Autopilot Integration And Testing, David Erdos, Steve Eugene Watkins

Electrical and Computer Engineering Faculty Research & Creative Works

The development of an Unmanned Aerial Vehicle (UAV) platform and the integration of avionics for a search and rescue UAV is examined. The project follows the guidelines for the UAV Challenge - Outback Rescue which is an international aerospace competition. The selection process for a commercial autopilot and avionics package is described. The selected system is integrated into a standard hobby remote control aircraft and configured for autonomous flight and navigation. The autopilot system must be tuned to the aircraft platform and flight characteristics. Flight tests are described for a GPS-based grid search pattern.

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Channel Estimation, Equalization And Phase Correction For Single Carrier Underwater Acoustic Communications, Jun Tao, Y. Rosa Zheng, Chengshan Xiao, Wen-Bin Yang, T. C. Yang Apr 2008

Channel Estimation, Equalization And Phase Correction For Single Carrier Underwater Acoustic Communications, Jun Tao, Y. Rosa Zheng, Chengshan Xiao, Wen-Bin Yang, T. C. Yang

Electrical and Computer Engineering Faculty Research & Creative Works

In this paper, we employ a time-domain channel estimation, equalization and phase correction scheme for single carrier single input multiple output (SIMO) underwater acoustic communications. In this scheme, Doppler shift, which is caused by relative motion between transducer (source) and hydrophones (receiver), is estimated and compensated in the received baseband signals. Then the channel is estimated using a small training block at the front of a transmitted data package, in which the data is artificially partitioned into consecutive data blocks. The estimated channel is utilized to equalize a block of received data, then the equalized data is processed by a …

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Simulation Of Doubly-Selective Compound K Fading Channels For Mobile-To-Mobile Communications, Yuan Liu, Jian Zhang, Y. Rosa Zheng Mar 2008

Simulation Of Doubly-Selective Compound K Fading Channels For Mobile-To-Mobile Communications, Yuan Liu, Jian Zhang, Y. Rosa Zheng

Electrical and Computer Engineering Faculty Research & Creative Works

A computer simulation model is proposed for discrete-time doubly-selective compound-K fading channel. It first generates multiple independent mobile-to-mobile Rayleigh fading Channel Impulse Response (CIR) using the non-isotropic scattering model, then generates the cross- and auto-correlated gamma shadowing matrix using the combination of the memoryless nonlinear transformation (MNLT) method and the decomposition methods. It then combines the complex Rayleigh CIR with the gamma shadowing matrix to yield the doubly-selective fading channel CIR whose envelop follows the compound K distribution. Simulation examples demonstrate that the proposed method can effectively produce compound K fading channel responses with satisfactory statistical properties.

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Output Feedback Controller For Operation Of Spark Ignition Engines At Lean Conditions Using Neural Networks, Jonathan B. Vance, Brian C. Kaul, Jagannathan Sarangapani, J. A. Drallmeier Mar 2008

Output Feedback Controller For Operation Of Spark Ignition Engines At Lean Conditions Using Neural Networks, Jonathan B. Vance, Brian C. Kaul, Jagannathan Sarangapani, J. A. Drallmeier

Electrical and Computer Engineering Faculty Research & Creative Works

Spark ignition (SI) engines operating at very lean conditions demonstrate significant nonlinear behavior by exhibiting cycle-to-cycle bifurcation of heat release. Past literature suggests that operating an engine under such lean conditions can significantly reduce NO emissions by as much as 30% and improve fuel efficiency by as much as 5%-10%. At lean conditions, the heat release per engine cycle is not close to constant, as it is when these engines operate under stoichiometric conditions where the equivalence ratio is 1.0. A neural network controller employing output feedback has shown ability in simulation to reduce the nonlinear cyclic dispersion observed under …

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Application Of Frustrated Total Internal Reflection Of Millimeter Waves For Detection And Evaluation Of Disbonds In Dielectric Joints, Sergey Kharkovsky, Emilio Alessandro Nanni, R. Zoughi Mar 2008

Application Of Frustrated Total Internal Reflection Of Millimeter Waves For Detection And Evaluation Of Disbonds In Dielectric Joints, Sergey Kharkovsky, Emilio Alessandro Nanni, R. Zoughi

Electrical and Computer Engineering Faculty Research & Creative Works

Millimeter waves penetrate inside of low loss dielectric materials and they are sensitive to the presence of internal interfaces and nonuniformities. This allows millimeter wave nondestructive inspection techniques to be utilized for inspecting dielectric composite structures. A disbond (a thin and extended airgap) in structures possessing adhesively bonded joints with complex geometries is commonly difficult to inspect. In this letter, we demonstrate the operational principle and the useful features of a millimeter wave technique, employing a frustrated total internal reflection of signals transmitted and received by dielectric waveguide probes for detecting and evaluating disbonds in such joints.

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Particle Swarm Optimization: Basic Concepts, Variants And Applications In Power Systems, Yamille Del Valle, Ganesh K. Venayagamoorthy, Salman Mohagheghi, Ronald G. Harley, J. C. Hernandez Mar 2008

Particle Swarm Optimization: Basic Concepts, Variants And Applications In Power Systems, Yamille Del Valle, Ganesh K. Venayagamoorthy, Salman Mohagheghi, Ronald G. Harley, J. C. Hernandez

Electrical and Computer Engineering Faculty Research & Creative Works

Many areas in power systems require solving one or more nonlinear optimization problems. While analytical methods might suffer from slow convergence and the curse of dimensionality, heuristics-based swarm intelligence can be an efficient alternative. Particle swarm optimization (PSO), part of the swarm intelligence family, is known to effectively solve large-scale nonlinear optimization problems. This paper presents a detailed overview of the basic concepts of PSO and its variants. Also, it provides a comprehensive survey on the power system applications that have benefited from the powerful nature of PSO as an optimization technique. For each application, technical details that are required …

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