Electrical and Computer Engineering Commons^™

On The Biophysics And Kinetics Of Toehold-Mediated Dna Strand Displacement, Bernard Yurke

Electrical and Computer Engineering Faculty Publications and Presentations

Dynamic DNA nanotechnology often uses toehold-mediated strand displacement for controlling reaction kinetics. Although the dependence of strand displacement kinetics on toehold length has been experimentally characterized and phenomenologically modeled, detailed biophysical understanding has remained elusive. Here, we study strand displacement at multiple levels of detail, using an intuitive model of a random walk on a 1D energy landscape, a secondary structure kinetics model with single base-pair steps and a coarse-grained molecular model that incorporates 3D geometric and steric effects. Further, we experimentally investigate the thermodynamics of three-way branch migration. Two factors explain the dependence of strand displacement kinetics on toehold …

An Efficient Preconditioning Scheme For Eigenanalysis Of Inhomogeneously Loaded Rectangular Cavities, Qi I. Dai, Yat Hei Lo, Lijun Jiang, Weng Cho Chew

Electrical and Computer Engineering Faculty Research & Creative Works

An efficient preconditioning scheme for the eigenanalysis of inhomogeneously loaded rectangular cavities is presented. Such structures are modeled with the finite-difference frequency-domain (FDFD) method, while the desired interior eigen-spectra are sought for by Arnoldi iterations with the shiftand-invert operation. In large scale problems, the inversion can only be performed iteratively. A preconditioner is constructed in order to accelerate the inversion. It can effectively shrink the spectrum of the governing matrix, and can be solved for by using fast discrete sine and cosine transforms (DST's and DCT's). The efficiency of this scheme is demonstrated by several numerical examples. © 2013 IEEE.

Eagle-Eye: A Near-Optimal Statistical Framework For Noise Sensor Placement, Tao Wang, Chun Zhang, Jinjun Xiong, Yiyu Shi

Electrical and Computer Engineering Faculty Research & Creative Works

The relentless technology scaling has led to significantly reduced noise margin and complicated functionalities. As such, design time techniques per se are less likely to ensure power integrity, resulting in runtime voltage emergencies. To alleviate the issue, recently several works have shed light on the possibilities of dynamic noise management systems. Most of these works rely on on-chip noise sensors to accurately capture voltage emergencies. However, they all assume, either implicitly or explicitly, that the placement of the sensors is given. It remains an open problem in the literature how to optimally place a given number of noise sensors for …

One Dimensional Multiple Periodic Composite Right/Left Handed (Crlh) Structures, Zi Long Ma, Li (Lijun) Jun Jiang, Shulabh Gupta, Wei E.I. Sha

Electrical and Computer Engineering Faculty Research & Creative Works

The wave-propagation characteristics in a one-dimensional multiple-periodic (MP) Composite right/left-handed (CRLH) structures is presented, where it is found that an increase in the number of unit cells in each supercell leads to new passbands and stopbands. To understand this phenomenon, the network parameters are employed for the theoretical analysis. Detailed dispersion characteristics and the relation between passbands and sub-periodicities are investigated using both analytical and full-wave results, and the reasons for their emergence is qualitatively discussed. Besides, its application to multi-band leaky-wave radiators is also suggested. © 2013 IEEE.

Limitations On High-Frequency Permeability Of Magnetic Materials, Konstantin N. Rozanov, Marina Koledintseva

Electrical and Computer Engineering Faculty Research & Creative Works

Engineering of magnetic composites with high microwave permeability is important for EMC/EMI and other applications. One of the challenging problems is to determine constraints on the achievable high-frequency permeability of magnetic composites. The objective of the present paper is to analyze the data available from the literature on the microwave permeability constraints and derive a generalized constraint condition. It is well known that in many practical occasions the actual magnetic frequency dispersion curves differ from the Lorentzian behavior. For these cases, an integral form of the constraint may be useful. Possible applications of the integral constraint are discussed for the …

A Probabilistic Analysis Of Islanding Effects In A Modeled Distribution System With Renewable Resources, Paul Gooding

All Theses

For this research, an investigation was undertaken regarding the inclusion of renewable resources into the distribution system. This incorporated the increasing prevalence of solar and wind resources, as well as the development of islanding capabilities within distribution systems.

Design Of An Optical Position Sensor For Microfiber Actuators, Luxi Cheng

All Theses

This thesis introduces a new type of sensor that detects the position information of a paramagnetic microfiber and transforms it to computational electrical signal. The original purpose of the sensor is to solve the problem of feedback signal detection of the microfiber control system, which is the problem of detecting the position information for the microfiber. The microfiber will be presented as the experimental object of this sensor to test its capability. A novel optical based approach is used to transfer the position signal to a computer scrutable signal for further analysis.

The purpose of the sensor design comes from …

Speech Enhancement By Exploiting The Baseband Phase Structure Of Voiced Speech For Effective Non-Stationary Noise Estimation, Sanjay Patil

All Theses

Speech enhancement is one of the most important and challenging issues in the speech communication and signal processing field. It aims to minimize the effect of additive noise on the quality and intelligibility of the speech signal. Speech quality is the measure of noise remaining after the processing on the speech signal and of how pleasant the resulting speech sounds, while intelligibility refers to the accuracy of understanding speech. Speech enhancement algorithms are designed to remove the additive noise with minimum speech distortion.The task of speech enhancement is challenging due to lack of knowledge about the corrupting noise. Hence, the …

High Voltage Pulse Measurement System, Angelo J. Ballungay

Master's Theses

Using isolation and noise immunity techniques, this thesis designs and constructs a low cost measurement system to safely and accurately measure high voltage, high frequency pulses in harsh EM environments. High voltage pulses apply to medical, plasma, and food industries. The difficulty of accurately measuring high voltage pulses continues to pose an issue. Measuring high voltage systems can cause damage to the system, the measurement system, and the user. High voltage and high frequency pulses create a harsh environment of electromagnetic fields that can disrupt the circuitry of the measurement system and harm the user. Implementing isolation from the high …

Enhancing Gan Led Efficiency Through Nano-Gratings And Standing Wave Analysis, Gabriel M. Halpin

Master's Theses

Improving energy efficient lighting is a necessary step in reducing energy consumption.Lighting currently consumes 17% of all U.S. residential and commercial electricity, but a report from the U.S. Office of Energy Efficiency and Renewable Energy projects that switching to LED lighting over the next 20 years will save 46% of electricity used in lighting.GaN LEDs are used for their efficient conversion of electricity to light, but improving GaN efficiency requires optically engineering the chip to extract more light.Total internal reflection limits GaN LED performance since light must approach the chip surface within 23.6° of normal to escape into air.This thesis …

Design Of A Low Power Cargo Security Device Using A Micropower Ultra-Wideband Impulse Radar, Brian M. Wihl

Master's Theses

Each year, thousands of cargo containers are broken into during shipping, costing billions of dollars in lost and damaged goods. In addition to removing its contents, intruders can also add unwanted and dangerous materials to a container, posing a threat to National Security. The possibilities of cargo container break-ins require that the containers go through check points at which they are physically searched. These searches often require the opening of the container, unloading and inspecting all cargo, and then loading the container and resealing it. This is a long and costly process.

Because of the high costs of break-ins and …

Offshore Wind Energy Study And Its Impact On South Carolina Transmission System, Tingting Wang

All Dissertations

As one of the renewable resources, wind energy is developing dramatically in last ten years. Offshore wind energy, with more stable speed and less environmental impact than onshore wind, will be the direction of large scale wind industry. Large scale wind farm penetration affects power system operation, planning and control. Studies concerning type III turbine based wind farm integration problems such as wind intermittency, harmonics, low voltage ride through capability have made great progress. However, there are few investigations concerning switching transient impacts of large scale type III turbine based offshore wind farm in transmission systems. This topic will gain …

Design And Development Of A Low-Cost Handheld Picoammeter, Malcolm Stagg

Honors Capstones

No abstract provided.

Impact Of Plug In Electric Vehicle Battery Charging On A Distribution System Based On Real-Time Digital Simulator, Abdulelah Yousef Alharbi

Masters Theses and Doctoral Dissertations

This study investigates the impact of the electric vehicles (EVs’) battery charging on the distribution system in terms of maximum voltage deviation, voltage unbalance at various locations, transformers overloading, and introducing new peaks into the system. In this research, a 12.47 kV real distribution network has been modeled using real time digital simulator, using real data from a power distributor. The study presents four different scenarios of uncoordinated EVs integration for two different charging times (evening and night) and two different charging rates (level I and level II) at different penetration levels ranging from 10% to 100%. Voltage unbalance at …

Fea Estimation And Experimental Validation Of Solid Rotor And Magnet Eddy Current Loss In Single-Sided Axial Flux Permanent Magnet Machines, Xu Yang

Department of Electrical and Computer Engineering: Dissertations, Theses, and Student Research

The rotor and magnet loss in single-sided axial ux permanent magnet (AFPM) machines with non-overlapped windings is studied in this dissertation. Finite element analysis (FEA) estimations of the loss are carried out using both 2D and 3D modeling. The rotor and magnet losses are determined separately for stator slot passing and MMF space harmonics from currents in the stator. The segregation of loss between the solid rotor plate and the magnet is addressed. The eddy current loss reduction by magnet segmentation is discussed as well. Two prototype 24 slot/22 pole single-sided AFPMs, fabricated with both single layer (SL) and double …

Investigation Of The Effects Of Rapid Thermal Annealing On Mbe Grown Gaasbi/Gaas Heterostructures For Optoelectronic Devices, Perry C. Grant

Graduate Theses and Dissertations

High efficiency optoelectronic devices rely on high quality materials making up the device structure. The scope of this thesis investigates the effectiveness of rapid thermal annealing (RTA) at improving the material quality of GaAsBi/GaAs heterostructures. During the fabrication of a device, the contacts of the device had the rapid thermal annealing process accomplished to produce ohmic contacts and this research explored if this annealing treatment degraded the quantum wells that made up the active region of a device. To investigate these effects, a system to measure the photoluminescence of the material system was constructed utilizing Fourier Transform Infrared Spectroscopy. The …

Instrumentation Electronics For An Integrated Electrophysiology Data Acquisition And Stimulation System, Donovan Squires

Masters Theses

The Neurobiology Engineering Laboratory at Western Michigan University has need of an electrophysiology instrumentation system combining generation of multiple arbitrary stimulation waveforms and recording of action potentials on multiple channels. Electronics for an instrumentation system with the capability of generating four unique stimulation waveforms and recording action potentials on eight channels were developed and implemented on a printed circuit board. Collaboration with fellow graduate student, Mr. Kyle Batzer, who developed firmware and software for the instrumentation system as described in his thesis, was essential for successful realization of the instrumentation system. Knowledge gained and reported by previous students working in …

Laminar Flow Hood System Design, Sophie Schneider

Electrical Engineering

In 2011 health care costs for transplants were over 12 billion dollars in the United States for evaluation, procurement, facilities use, physicians, and post-transplant check-ups. In 2012 burns hospitalized 40,000 people and over 17,000 people received organ transplants. Sadly, the number of organ donors greatly lags the number of people on the transplant waiting list and the gap has widened over the decades. While preventative health care is extremely important, researching tissue engineering (TE) to treat patients in fatal condition provides alternatives for replacing or repairing a variety of damaged tissue. These alternative treatments can considerably reduce the supply-demand gap …

Portable Nano-Hydro Power Generator For The Dc House Project, Andrew Aw, James Biggs

Electrical Engineering

This senior project report explains the construction and design of a small, portable water generator that converts kinetic energy flowing in small creeks to electrical energy as a renewable source of energy for the DC House. The DC House, in short, is a project to build a self-sustainable house for Third World countries that utilizes only DC electricity. The system consists of two converters and a charge controller for a 12V lead-acid battery. The first converter converts the hydro generator voltage output to 15 Volts for safe and proper charging of the lead-acid battery by the charge controller. The second …

An Enhanced Mixed-Form Fast Multipole Algorithm Using Rotation Methods, Ling Ling Meng, Li (Lijun) Jun Jiang

Electrical and Computer Engineering Faculty Research & Creative Works

In this paper, the broadband accuracy of the mixed-form fast multipole algorithm (MF-FMA) is improved by applying rotation techniques. Two kinds of rotation methods are employed respectively. One is the coordinate system rotation technique. The other one is the pseudospectral projection based on fast Fourier transform (FFT). Either of them has certain advantages depending on the number of multipoles. Through rotation, translation matrices become very sparse, which enables us to save the storage as well as the CPU time. Hence, we can increase the number of multipoles in the low frequency regime to shift up the transition region of MF-FMA. …

A Compact Hf/Uhf Dual Band Rfid Tag Antenna, Zi Long Ma, Li (Lijun) Jun Jiang, Jingtian Xi, Terry Tao Ye

Electrical and Computer Engineering Faculty Research & Creative Works

This paper presents a novel dual band RFID (radio frequency identification) tag antenna. Two challenges are faced: the compact dimension and the impaired bandwidth due to the couplings between two band structures. A spiral coil is designed to handle the HF (13.56MHz) near field coupling, and a diagonal symmetric design consisting of two meander lines are placed inside the coil for UHF band (915MHz). This structure supports multiple resonance modes around 915MHz to broaden the working bandwidth under the large inductive circumstance from the HF coil. The proposed antenna is easy to adjust by both coarse tuning and fine tuning. …

Three Dimensional Polarization Controllable Electromagnetic Cell, Bo Zhu, Weng Cho Chew, Lijun Jiang

Electrical and Computer Engineering Faculty Research & Creative Works

We demonstrate an electromagnetic (EM) cell that can generate uniform electric field with three dimensional (3D) polarization dynamic control for the EM compatibility/interference (EMC/EMI) testing. 3D orthogonal slotline structures are designed and utilized to build the walls of the EM cell. By feeding the slotlines in phase and terminating them with matching loads, the uniform electric field similar to a standing wave is produced by two slotline modes propagating in opposite directions inside the cell. Microwave switches are integrated into the slotlines so that we can choose the operating slotline dynamically and change its orientation in a 3D manner by …

Co-Simulation Of Distributive And Lumped Systems Using The Discontinuous Galerkin Time Domain Finite Element Method, Ping Li, Li (Lijun) Jun Jiang

Electrical and Computer Engineering Faculty Research & Creative Works

The signal integrity and power integrity analysis of 3D integrated circuits or other EMC/EMI systems usually separate the lumped circuit modeling and the distributive system modeling. However, due to the high density of integration, it is not proper to separate them in the modeling process anymore. In this paper, a hybrid electromagnetics (EM)-circuit simulator is proposed for incorporating multiport lumped circuit networks through their admittance matrices into the discontinuous Galerkin time-domain finite element method (DGTDFEM). The admittance matrix in the Laplace-domain can be derived analytically or obtained from network parameters such as S-parameters in the frequency domain. To convert frequency …

Chipless Rfid Tags Based On Multiple Band-Rejected Planar Log-Periodic Antennas, Shulabh Gupta, Li (Lijun) Jun Jiang

Electrical and Computer Engineering Faculty Research & Creative Works

A passive chipless Radio-frequency identification (RFID) tag is proposed based on the tailorable band-rejection property of the log-periodic (LP) antennas. The proposed tag principle is successfully demonstrated using full-wave simulations, where the absence and presence of the band-rejection in VSWR and thus radiation gain, is shown to carry the bit information. Due to the large number of dipole radiators on the LP aperture, the proposed tag can easily support large number of codes, providing a potential solution for limited number of bits in conventional chipless tags. © 2013 IEEE.

Modeling Radiated Emissions Through Shielding Boxes Based On The Tangential Electrical Field Samplings Over Openings, Ping Li, Li (Lijun) Jun Jiang

Electrical and Computer Engineering Faculty Research & Creative Works

The radiation from radiators such as PCBs inside an enclosed shielding box with ventilation slots is an important issue for electromagnetic compatibility or interference characterizations. In this paper, a two-step process is proposed based on the equivalence principle and the electric field integral equation method to complete the radiation prediction. The tangential electric fields over the slots on shielding boxes are first sampled to be the equivalent magnetic currents radiated from internal PCBs. In the second step, to avoid the computation of complex nonanalytical dyadic Green's functions when the field radiation is computed directly from the equivalent source, the surface …

Enhanced A-Efie With Calderón Multiplicative Preconditioner, Sheng Sun, Lijun Jiang, Weng Cho Chew

Electrical and Computer Engineering Faculty Research & Creative Works

In this work, a Calderón multiplicative preconditioner (CMP) is proposed for the augmented electric field integral equation (A-EFIE) to improve the convergence. To avoid the imbalance between the vector potential and the scalar potential in the traditional EFIE, A-EFIE considers both the charge and the current as unknowns. After implementing the appropriate frequency scaling and the enforcement of charge neutrality, its formulation is also stable in the low-frequency regime and applicable for large-scale and complex problems. Instead of using other preconditioners, Calderón preconditioning converts the first kind integral equations into the second kind, thus improving the spectrum of the original …

A New Coulomb Gauge Based Electric Field Integral Equation Method, Xiaoyan Y.Z. Xiong, Li (Lijun) Jun Jiang, Wei E.I. Sha, Yat Hei Lo

Electrical and Computer Engineering Faculty Research & Creative Works

The electric field integral equation (EFIE) method is one of the most commonly-adopted computational electromagnetic methods. Its popularity stems from the efficient surface triangulation, excellent numerical precision, and the powerful capability of handling open and complex geometries. However, when the frequency tends to zero, the method-of-moment (MoM) solution of EFIE using the Rao-Wilton-Glisson (RWG) basis functions suffers from the low-frequency breakdown, where the contribution from the vector potential is extremely imbalanced with that from the scalar potential. As a result, the matrix representation of EFIE operator is highly ill-conditioned and cannot be inverted reliably and efficiently. © 2013 IEEE.

Analysis Of The Permeability Spectra Of Spinel Ferrite Composites Using Mixing Rules, Takanori Tsutaoka, Teruhiro Kasagi, Kenichi Hatakeyama, Marina Koledintseva

Electrical and Computer Engineering Faculty Research & Creative Works

Magnetic permeability spectra of composite materials containing spinel ferrites (Ni-Zn or Mn-Zn types) have been studied using a permeability dispersion formula by the numerical analysis. The variation of d.c. permeability and the frequency dispersion parameters due to domain wall and gyromagnetic spin resonances with particle content were evaluated using two mixing rules, Coherent Model Approximation (CMA) and Maxwell-Garnet Approximation (MGA) assuming the isotropic particle shape. The variation of d.c. permeability with particle content for spinel ferrite composite can be predicted by the CMA and MGA using the permeability value of embedded ferrite. The dc susceptibility and resonance frequency of domain …

Analysis Of Waveguides Filled With Uniaxial Media And Metamaterials For Filter Applications Using The Mode Matching Method, Luke Murphy

Dissertations - ALL

This dissertation will explore the analysis of waveguide discontinuities for the purpose of dielectric filled waveguide filter analysis and design. The filling media studied are uniaxial media and uniaxial media embedded with metamaterial. A literary search provides numerous methods and numerical techniques for analyzing waveguide class problems, but ultimately the Mode Matching Method (MMM) is chosen as the numerical analysis technique for this dissertation.

An overview of waveguide theory and its application to the Mode Matching Method are presented. The Mode Matching Method is then used to analyze simple cases to confirm the numerical accuracy. Once accuracy is confirmed, Mode …

Retrieval Of Free Space Radiation Patterns Through Measured Data In A Non-Anechoic Environment, Weixin Zhao

Dissertations - ALL

Antenna pattern measurements are usually carried out in an anechoic chamber. However, a good anechoic chamber is very expensive to construct. Previous research has attempted to compensate for the effects of extraneous fields measured in a non-anechoic environment to obtain a free space pattern that would be measured in an anechoic chamber. Existing compensation techniques are like the Test Zone Field compensation method, the Fast-Fourier-Transform-based method, the Matrix Pencil method, and the Antenna Pattern Comparison technique.

This work illustrates and extends a deconvolution methodology which allows the antenna measurement under a non-anechoic test environment and retrieves the free space radiation …