Electrical and Computer Engineering Commons^™

Computation Offloading Decisions For Reducing Completion Time, Salvador Melendez

Open Access Theses & Dissertations

Mobile devices are being widely used in many applications such as image processing, computer vision (e.g. face detection and recognition), wearable computing, language translation, and battlefield operations. However, mobile devices are constrained in terms of their battery life, processor performance, storage capacity, and network bandwidth. To overcome these issues, there is an approach called Computation Offloading, also known as cyber-foraging and surrogate computing. Computation offloading consists of migrating computational jobs from a mobile device to more powerful remote computing resources. Upon completion of the job, the results are sent back to the mobile device. However, a decision must be made; …

Project Maelstrom: Forensic Analysis Of The Bittorrent-Powered Browser, Jason Farina, M-Tahar Kechadi, Mark Scanlon

Journal of Digital Forensics, Security and Law

In April 2015, BitTorrent Inc. released their distributed peer-to-peer powered browser, Project Maelstrom, into public beta. The browser facilitates a new alternative website distribution paradigm to the traditional HTTP-based, client-server model. This decentralised web is powered by each of the visitors accessing each Maelstrom hosted website. Each user shares their copy of the website;s source code and multimedia content with new visitors. As a result, a Maelstrom hosted website cannot be taken offline by law enforcement or any other parties. Due to this open distribution model, a number of interesting censorship, security and privacy considerations are raised. This paper explores …

Analysis Of The Tapered Transition Waveguide, Ryan J. Shaver

Browse all Theses and Dissertations

The tapered transition waveguide is used in waveguide measurement systems for characterizing biaxial electromagnetic properties of materials, but its complex geometry does not support an analytic field solution. To ensure single-mode field behavior, the system includes sections of standard waveguides that only support the dominant mode. As a result, full-wave modeling and simulation of the system is exceedingly large.

Using the finite-element method to analyze the high-order modes at the junctions and to explore field configurations within the transition altering geometry, it is shown that besides the TE10 mode, the TE11 mode is significant. Then, two methods are proposed for …

Strain-Induced Energy Band-Gap Opening Of Silicene, Zhonghang Ji

Browse all Theses and Dissertations

Inspired by the success of graphene, various two dimensional (2D) structures on different substrates have been proposed. Among others, an allotropic form of silicon, coined "silicene" was shown to exhibit similar properties with graphene of a zero band gap and a Dirac cone shape at the K point in the Brillouin zone. Similar to its counterpart graphene, one of the main obstacles to applying silicene in modern electronics is the lack of an energy band gap. In this work, a systematic study was presented on the structural and electronic properties of single and bi-layered silicon films under various in-plane biaxial …

Design And Performance Analysis Of Magnetic Adder And 16-Bit Mram Using Magnetic Tunnel Junction Transistor, Surya Kiran Akkaladevi

Browse all Theses and Dissertations

The scaling down of IC's based on CMOS technology faces significant challenges due to technology advancing factors. The stand-by power becomes comparable to active power due to the increasing leakage current. Power gating and various low-power schemes have been proposed in the past to reduce the stand-by power in CMOS designs. As most random access memory (RAM) used for primary storage in personal computers is volatile memory, which needs constant voltage (power on) to store the data and results in a higher stand-by power. Magnetic Tunnel Junctions (MTJ) transistor has feature of non-volatility, endurance and high density, which makes it …

Signal Subspace Processing In The Beam Space Of A True Time Delay Beamformer Bank, Nathan Allen Wilkins

Browse all Theses and Dissertations

A number of techniques for Radio Frequency (RF) source location for wide bandwidth signals have been described that utilize coherent signal subspace processing, but often suffer from limitations such as the requirement for preliminary source location estimation, the need to apply the technique iteratively, computational expense or others. This dissertation examines a method that performs subspace processing of the data from a bank of true time delay beamformers. The spatial diversity of the beamformer bank alleviates the need for a preliminary estimate while simultaneously reducing the dimensionality of subsequent signal subspace processing resulting in computational efficiency. The pointing direction of …

Hardware Trojan Detection In Cryptography Ip Cores By Library Encoding Method, Dinesh Varma Penumetcha

Browse all Theses and Dissertations

Security is the primary issue in current internet world through both software and hardware. The ever increase in demand of consumer electronics requires less design cycle. To speedup design cycle, companies are approaching third parties for common applications IPs like USB, cryptography, DSP etc. These third parties can introduce a malicious content, which is called Trojan. Trojan in the netlist can activate only with special input/trigger. Available Trojan detection techniques like delay, area, power fingerprinting techniques and Automatic Test Pattern Generator (ATPG) method are not suitable as they take more time, less accurate. This thesis presents a hardware Trojan detection …

Predicting Scenarios For Successful Autodissemination Of Pyriproxyfen By Malaria Vectors From Their Resting Sites To Aquatic Habitats; Description And Simulation Analysis Of A Field-Parameterizable Model, Samson Sifael Kiware, George F. Corliss, Stephen Merrill, Dickson W. Lwetoijera, Gregor J. Devine, Silas Majambere, Gerry F. Killeen

Electrical and Computer Engineering Faculty Research and Publications

Background

Large-cage experiments indicate pyriproxifen (PPF) can be transferred from resting sites to aquatic habitats by Anopheles arabiensis - malaria vector mosquitoes to inhibit emergence of their own offspring. PPF coverage is amplified twice: (1) partial coverage of resting sites with PPF contamination results in far higher contamination coverage of adult mosquitoes because they are mobile and use numerous resting sites per gonotrophic cycle, and (2) even greater contamination coverage of aquatic habitats results from accumulation of PPF from multiple oviposition events.

Methods and Findings

Deterministic mathematical models are described that use only field-measurable input parameters and capture the biological …

Design Of A 10-Bit 1.2 Gs/S Digital-To-Analog Converter In 90 Nm Cmos, Tyler J. Moody

Browse all Theses and Dissertations

Digital analog converters bridge the gap between digital signal processing chips, and power amplifiers that transmit analog signals. Communications systems require ever increasing bandwidth, however data converters are typically the bottleneck in these systems. This thesis presents the design of a high speed current steering DAC using CMOS 90 nm technology. The resolution of the converter is 10 bits, segmented into 6 thermometer encoded MSB current cells, and 4 binary weighted LSB current cells. Each of the sub-components, such as the binary-thermometer encoder, digital latch, current cell, reconstruction filter, are discussed in detail. The current cells were designed with transistor …

Wideband Automatic Gain Control Design In 130 Nm Cmos Process For Wireless Receiver Applications, Joseph Benito Strzelecki

Browse all Theses and Dissertations

An analog automatic gain control circuit (AGC) and mixer were implemented in 130 nm CMOS technology. The proposed AGC was intended for implementation into a wireless receiver chain. Design specifications required a 60 dB tuning range on the output of the AGC, a settling time within several microseconds, and minimum circuit complexity to reduce area usage and power consumption.

Desired AGC functionality was achieved through the use of four nonlinear variable gain amplifiers (VGAs) and a single LC filter in the forward path of the circuit and a control loop containing an RMS power detector, a multistage comparator, and a …

Compressive Sensing Analog Front End Design In 180 Nm Cmos Technology, Julin Mukeshkumar Shah

Browse all Theses and Dissertations

In order to accurately reconstruct signal waveform a signal must be sampled at least twice as fast as the bandwidth of the signal. Ultra Wideband (UWB) signals have extraordinary potential for high information transmission while a central focus of wireless has been the mobile communication. It is an emerging area that involves development of RF sensing and spectral applications over multiple GHz bandwidths. Even though our technology is improving, it is very challenging to build ADC's that are compatible and keep up with the growth of ultra-wideband range. Compressive sensing does "sampling" and "compressing" at the same time and exploits …

Mixed Signal Detection And Parameter Estimation Based On Second-Order Cyclostationary Features, Dong Li

Browse all Theses and Dissertations

Signal detection and radio frequency (RF) parameter estimation have received a lot of attention in recent years due to the need of spectrum sensing in many military and civilian communication applications. In most of existing work, the target signal is assumed to be a single RF signal with no overlapping with other RF signals. However, in a spectrally congested and spectrally contested environment, multiple signals are often mixed together at the signal detector with significant overlap in spectrum. Conventional frequency analysis through Fourier transform is not capable of detecting mixed signals with significant spectral overlap. In this thesis, we first …

Ambiguity-Based Classification Of Phase Modulated Waveforms, Anthony Buchenroth

Browse all Theses and Dissertations

Accurate classification or recognition of phase modulated radar waveforms, typically accomplished via the combination of pulse parameter estimates and matched?filtering, poses a simple problem in ideal conditions. Recognition of these waveforms aids in various spectrum management, surveillance, and electronic warfare (EW) applications. In less than ideal conditions, carrier frequency, time offset, pulse amplitude, initial phase, and bandwidth are unknown to the EW receiver rendering the application of a matched filter futile. This effort investigates the use of features extracted from the ambiguity function of an intercepted pulse. Specifically, this effort will expand upon the methodology of previous work done which …

Visualization Of 4d Q2psk And Ce Q2psk In Ideal Bandlimited Channels, Milton I. Quinteros, Edit J. Kaminsky, Kenneth V. Cartwright

Electrical Engineering Faculty Publications

This paper presents new visualization techniques for 4D Quadrature-Quadrature Phase Shift Keying (Q2PSK), Saha’s Constant Envelope (CE) Q2PSK, and Cartwright’s CEQ2PSK in ideal bandlimited channels. The signal diagrams analyzed are: time-signal eye patterns for 4D passband signals, 2D complex trajectory diagrams of baseband signals, and time-signal eye patterns for the 1D outputs of the baseband matched filter. These methods may be applied to other multidimensional modulation systems to obtain insight into the effects of noise, interference, and channel filtering.

Inn Nems And Heterojunction Devices For Sensing Applications, Alina Wilson

Theses and Dissertations

Recent research trends in chemical and biological sensing have been geared toward developing molecular sensor devices that are fast, inexpensive, miniaturized, have low power consumption and are portable. The performance of these devices can be dramatically improved by utilizing multimodal detection techniques, new materials and nanofabrication technologies. To develop such sensor devices, we utilized Indium Nitride (InN) nanowires (NWs) to fabricate nanoelectromechanical system (NEMS) based sensors and Graphene/InN NW heterojunctions, and InN thin films to fabricate Graphene/InN thin film heterojunction based sensors. InN NWs, which exhibit interesting properties including high carrier density, superior electron mobility, strong surface charge accumulation, and …

Stargrazer One: A New Architecture For Distributed Maximum Power Point Tracking Of Solar Photovoltaic Sources, Edgard Munoz-Coreas

Theses and Dissertations--Electrical and Computer Engineering

The yield from a solar photovoltaic (PV) source is dependent on factors such as light and temperature. A control system called a maximum power point tracker (MPPT) ensures that the yield from a solar PV source is maximized in spite of these factors. This thesis presents a novel implementation of a perturb and observe (PO) MPPT.

The implementation uses a switched capacitor step down converter and a custom digital circuit implementation of the PO algorithm. Working in tandem, the switched capacitor step down converter and the custom digital circuit implementation were able to successfully track the maximum power point of …

Nanostructured Semiconductor Device Design In Solar Cells, Hongmei Dang

Theses and Dissertations--Electrical and Computer Engineering

We demonstrate the use of embedded CdS nanowires in improving spectral transmission loss and the low mechanical and electrical robustness of planar CdS window layer and thus enhancing the quantum efficiency and the reliability of the CdS-CdTe solar cells. CdS nanowire window layer enables light transmission gain at 300nm-550nm. A nearly ideal spectral response of quantum efficiency at a wide spectrum range provides an evidence for improving light transmission in the window layer and enhancing absorption and carrier generation in absorber. Nanowire CdS/CdTe solar cells with Cu/graphite/silver paste as back contacts, on SnO₂/ITO-soda lime glass substrates, yield the …

Constrained Divergence-Conforming Basis Functions For Method Of Moments Discretizations In Electromagnetics, Robert Pfeiffer

Theses and Dissertations--Electrical and Computer Engineering

Higher-order basis functions are widely used to model currents and fields in numerical simulations of electromagnetics problems because of the greater accuracy and computational efficiency they can provide. Different problem formulations, such as method of moments (MoM) and the finite element method (FEM) require different constraints on basis functions for optimal performance, such as normal or tangential continuity between cells. In this thesis, a method of automatically generating bases that satisfy the desired basis constraints is applied to a MoM formulation for scattering problems using surface integral equations. Numerical results demonstrate the accuracy of this approach, and show good system …

Explorations For Efficient Reversible Barrel Shifters And Their Mappings In Qca Nanocomputing, Ke Chen

Theses and Dissertations--Electrical and Computer Engineering

This thesis is based on promising computing paradigm of reversible logic which generates unique outputs out of the inputs and. Reversible logic circuits maintain one-to-one mapping inside of the inputs and the outputs. Compared to the traditional irreversible computation, reversible logic circuit has the advantage that it successfully avoids the information loss during computations. Also, reversible logic is useful to design ultra-low-power nanocomputing circuits, circuits for quantum computing, and the nanocircuits that are testable in nature. Reversible computing circuits require the ancilla inputs and the garbage outputs. Ancilla input is the constant input in reversible circuits. Garbage output is the …

Multifrequency Averaging Of Hysteresis-Current-Controlled Dc-Dc Converters, Yingying Liu

Theses and Dissertations--Electrical and Computer Engineering

Multifrequency averaging is one of the widely used modeling and simulation techniques today for the analysis and design of power electronic systems. This technique is capable of providing the average behavior as well as the ripple behavior of power electronic systems. Hysteresis current control has fast response and internal current stability through controlling switches to maintain the current within a given hysteresis band of a given current command. However the state space variables in a hysteresis controlled system cannot be directly approached by multifrequency averaging method because of time varing switching frequency. In this thesis, a method of applying multifrequency …

A New Islanding Detection Method Based On Wavelet-Transform And Ann For Inverter Assisted Distributed Generator, Zhengyuan Guan

Theses and Dissertations--Electrical and Computer Engineering

Nowadays islanding has become a big issue with the increasing use of distributed generators in power system. In order to effectively detect islanding after DG disconnects from main source, author first studied two passive islanding methods in this thesis: THD&VU method and wavelet-transform method. Compared with other passive methods, each of them has small non-detection zone, but both of them are based on the threshold limit, which is very hard to set. What’s more, when these two methods were applied to practical signals distorted with noise, they performed worse than anticipated.

Thus, a new composite intelligent based method is presented …

The Constrained Locally Corrected Nyström Method, Nastaran Hendijani

Theses and Dissertations--Electrical and Computer Engineering

In this dissertation a generalization of the locally corrected Nyström (LCN) discretization method is outlined wherein sparse transformations of the LCN system matrix are obtained via singular value decompositions of local constraint matrices. The local constraint matrices are used to impose normal continuity of the currents across boundaries shared by mesh elements. For this reason, the method is called constrained LCN (CLCN).

Due to the CLCN’s simplicity and flexibility, it is straightforward to develop high order CLCN systems for different formulations and mesh element types. As compared to the LCN, the CLCN method offers memory savings and improved accuracy when …

Average-Value Modeling Of Hysteresis Current Control In Power Electronics, Hanling Chen

Theses and Dissertations--Electrical and Computer Engineering

Hysteresis current control has been widely used in power electronics with the advantages of fast dynamic response under parameter, line and load variation and ensured stability. However, a main disadvantage of hysteresis current control is the uncertain and varying switching frequency which makes it difficult to form an average-value model. The changing switching frequency and unspecified switching duty cycle make conventional average-value models based on PWM control difficult to apply directly to converters that are controlled by hysteresis current control.

In this work, a new method for average-value modeling of hysteresis current control in boost converters, three-phase inverters, and brushless …

Compensation Methods For Demand Response, Zhaofeng Wang

Theses and Dissertations--Electrical and Computer Engineering

Recently, more and more disputations about how demand response should be compensated have arisen. Moreover, the court is about to rehear the Order 745. It probably will have significant impact on the whole working system used to be built for demand response before. Nowadays, some power companies and utilities think that they will endure profits leakage while demand response resources still are compensated.

In this research, knowledge of demand response, local marginal price, Order 745 and other related concept will be explained in detail in case of misunderstanding. Associated with all these knowledge, a possible compensation method will be proposed. …

A Reconfigurable Spice-Based Cmos Lna Design In 90 Nm Technology Using Ads Rfic Dynamic Link, Pushpak Vasanth Rayudu Arja

Browse all Theses and Dissertations

In this thesis, a reconfigurable dual band CMOS LNA with a switching-type circuit topology is proposed. The reconfigurable dual-band LNA can be tuned to operating fre- quency of either 1.575 GHz for global positioning system (GPS) or 2.4GHz for WLAN 802.11b standards. The simulated results performed power gain of 11.2 dB and 12.4 dB, noise figure of 3.4 dB and 2.9 dB, input return loss(S11) of -25.26 dB and-21.4 dB, third- order input intercept point of -3.12 dBm and -2.137 dBm and the design dissipates 8.9 mW and 4.68 mW of power at 1.2 V power supply at the two …

High Frequency Resolution Adaptive Thresholding Wideband Receiver System, Feiran Liu

Browse all Theses and Dissertations

Fast Fourier transformation (FFT) is widely used in wideband digital receivers to detect multiple signals. To achieve high dynamic range, the receiver has to increase analog-to-digital (ADC) resolution bits, which requires significant computation time and therefore increases receiver time resolution. The other challenge of FFT approach is two signals with a small frequency difference (i.e., less than five FFT frequency bins in most cases) cannot be detected simultaneous. This thesis presents an adaptive thresholding wideband digital receiver to accurately detect two simultaneous high dynamic range signals even when they are close to one FFT frequency bin. The receiver can perform …

Wide Tuning Range I/Q Dco Vco And A High Resolution Pfd Implementation In Cmos 90 Nm Technology, Eswar Raju Suraparaju

Browse all Theses and Dissertations

This thesis presents wide tuning range in-phase and quad-phase (I/Q) output digital control oscillator (DCO) and voltage control oscillator (VCO) and a simple high performance phase frequency detector (PFD) in 90 nm CMOS technology with 1.2 V power supply. The designed I/Q output DCO has an operating frequency range from 1.1-8.2 GHz with high resolution and wide linearity by using a novel skew delay structure. At 2.02GHz oscillation frequency, the measured phase noise of I/Q output DCO is -90.43dBc/Hz at an offset of 1 MHz offset and has 5 mW of power dissipation. A complementary series coupled quadrature VCO (S-QVCO) …

Verification And Validation Of A Transient Heat Exchanger Model, Jayme Lee Carper

Browse all Theses and Dissertations

A statistical based verification and validation process is applied to the transient modeling of a shell and tube heat exchanger. A generic model of a heat exchanger was developed based on first principles as a sub-system of a larger thermal system model. This model was originally created without any experimental data, as it was not readily available. To provide the data necessary to apply the validation process, a thermal emulator was designed and built that allowed control of all system inputs to the heat exchanger, while also providing the instrumentation to record all required data. A wide test matrix was …

Short Wave Infrared Imaging System For Night And Day Long Range Facial Recognition And Surveillance, Robert B. Martin

Graduate Theses, Dissertations, and Problem Reports (ETD)

The capability to detect, observe, and positively identify people at a distance is important to numerous security and defense applications. Traditional solutions for human detection and observation include long-range visible imagers for daytime and thermal infrared imagers for night-time use. Positive identification, through computer face recognition, requires facial imagery that can be repeatably matched to a database of visible spectrum facial mug shots. Nighttime identification at large distances is not possible with visible imagers due to lack of light, or with thermal infrared imagers due to poor correlation with visible facial imagery. An active-SWIR imaging system was developed that is …

Tunable Absorption Based On Plasmonic Nanostructures Loaded With Graphene, Christos Argyropoulos

Department of Electrical and Computer Engineering: Faculty Publications

We present simulations of a hybrid graphene-plasmonic device constituted by periodic metallic nanowires placed over a dielectric spacer layer and a metallic film. The spacer layer is composed of a thin silica layer combined with an one-atom-thick graphene sheet. An electrically controlled ultra-compact absorption modulator can be realized based on the proposed theoretical device.