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Full-Text Articles in Engineering

A Parallel Direct Method For Finite Element Electromagnetic Computations Based On Domain Decomposition, Javad Moshfegh Nov 2019

A Parallel Direct Method For Finite Element Electromagnetic Computations Based On Domain Decomposition, Javad Moshfegh

Doctoral Dissertations

High performance parallel computing and direct (factorization-based) solution methods have been the two main trends in electromagnetic computations in recent years. When time-harmonic (frequency-domain) Maxwell's equation are directly discretized with the Finite Element Method (FEM) or other Partial Differential Equation (PDE) methods, the resulting linear system of equations is sparse and indefinite, thus harder to efficiently factorize serially or in parallel than alternative methods e.g. integral equation solutions, that result in dense linear systems. State-of-the-art sparse matrix direct solvers such as MUMPS and PARDISO don't scale favorably, have low parallel efficiency and high memory footprint. This work ...


Time-Difference Circuits: Methodology, Design, And Digital Realization, Shuo Li Oct 2019

Time-Difference Circuits: Methodology, Design, And Digital Realization, Shuo Li

Doctoral Dissertations

This thesis presents innovations for a special class of circuits called Time Difference (TD) circuits. We introduce a signal processing methodology with TD signals that alters the target signal from a magnitude perspective to time interval between two time events and systematically organizes the primary TD functions abstracted from existing TD circuits and systems. The TD circuits draw attention from a broad range of application fields. In addition, highly evolved complementary metal-oxide-semiconductor (CMOS) technology suffers from various problems related to voltage and current amplitude signal processing methods. Compared to traditional analog and digital circuits, TD circuits bring several compelling features ...


Software-Defined Infrastructure For Iot-Based Energy Systems, Stephen Lee Oct 2019

Software-Defined Infrastructure For Iot-Based Energy Systems, Stephen Lee

Doctoral Dissertations

Internet of Things (IoT) devices are becoming an essential part of our everyday lives. These physical devices are connected to the internet and can measure or control the environment around us. Further, IoT devices are increasingly being used to monitor buildings, farms, health, and transportation. As these connected devices become more pervasive, these devices will generate vast amounts of data that can be used to gain insights and build intelligence into the system. At the same time, large-scale deployment of these devices will raise new challenges in efficiently managing and controlling them.

In this thesis, I argue that the IoT ...


Function And Dissipation In Finite State Automata - From Computing To Intelligence And Back, Natesh Ganesh Oct 2019

Function And Dissipation In Finite State Automata - From Computing To Intelligence And Back, Natesh Ganesh

Doctoral Dissertations

Society has benefited from the technological revolution and the tremendous growth in computing powered by Moore's law. However, we are fast approaching the ultimate physical limits in terms of both device sizes and the associated energy dissipation. It is important to characterize these limits in a physically grounded and implementation-agnostic manner, in order to capture the fundamental energy dissipation costs associated with performing computing operations with classical information in nano-scale quantum systems. It is also necessary to identify and understand the effect of quantum in-distinguishability, noise, and device variability on these dissipation limits. Identifying these parameters is crucial to ...


A Study On Controlling Power Supply Ramp-Up Time In Sram Pufs, Harshavardhan Ramanna Oct 2019

A Study On Controlling Power Supply Ramp-Up Time In Sram Pufs, Harshavardhan Ramanna

Masters Theses

With growing connectivity in the modern era, the risk of encrypted data stored in hardware being exposed to third-party adversaries is higher than ever. The security of encrypted data depends on the secrecy of the stored key. Conventional methods of storing keys in Non-Volatile Memory have been shown to be susceptible to physical attacks. Physically Unclonable Functions provide a unique alternative to conventional key storage. SRAM PUFs utilize inherent process variation caused during manufacturing to derive secret keys from the power-up values of SRAM memory cells.

This thesis analyzes the effect of supply ramp-up times on the reliability of SRAM ...


The Umass Experimental X-Band Radar (Umaxx): An Upgrade Of The Casa Ma-1 To Support Cross-Polarization Measurements, Jezabel Vilardell Sanchez Aug 2019

The Umass Experimental X-Band Radar (Umaxx): An Upgrade Of The Casa Ma-1 To Support Cross-Polarization Measurements, Jezabel Vilardell Sanchez

Masters Theses

Ground-based radars are instruments commonly used to surveil the precipitation climate of the surrounding areas. Weather events are characterized by collecting backscatter data and analyzing computed products such as the Reflectivity Factor, the Doppler Velocity, the Spectrum Width, the Differential Reflectivity, the Co-polar Correlation Coefficient and the Differential Propagation Phase. The ability of the radar to transmit different polarization waves, such as horizontal and vertical polarization, allow for further analysis of the weather given the capability to perform co-polar and cross-polar measurements. The Linear Depolarization Ratio is another computed product based on the difference in power between the co-polarized and ...


Sparsity In Machine Learning: An Information Selecting Perspective, Siwei Feng Jul 2019

Sparsity In Machine Learning: An Information Selecting Perspective, Siwei Feng

Doctoral Dissertations

Today we are living in a world awash with data. Large volumes of data are acquired, analyzed and applied to tasks through machine learning algorithms in nearly every area of science, business, and industry. For example, medical scientists analyze the gene expression data from a single specimen to learn the underlying causes of disease (e.g. cancer) and choose the best treatment; retailers can know more about customers' shopping habits from retail data to adjust their business strategies to better appeal to customers; suppliers can enhance supply chain success through supply chain systems built on knowledge sharing. However, it is ...


A Discrete-Time Technique For Linearity Enhancement Of Wideband Receivers, Mohammad Ghadiri Sadrabadi Jul 2019

A Discrete-Time Technique For Linearity Enhancement Of Wideband Receivers, Mohammad Ghadiri Sadrabadi

Doctoral Dissertations

A new signal processing technique is introduced to enhance the linearity performance of wideband radio frequency (RF) receivers. The proposed technique combines the advancements in mixer first architectures with a library of binary sequences as local oscillator signals to enable wide instantaneous bandwidth and high linearity for the RF receiver. To do so, N-bit pseudo-random-binary-sequences (PRBS) are used as local oscillator signals. The RF input signal is multiplied with the PRBS at the mixer and then averaged over the full sequence. This in effect reduces the amplitude of the signal and improves the overall linearity of the system. In order ...


Improving Resilience Of Communication In Information Dissemination For Time-Critical Applications, Rajvardhan Somraj Deshmukh Jul 2019

Improving Resilience Of Communication In Information Dissemination For Time-Critical Applications, Rajvardhan Somraj Deshmukh

Masters Theses

Severe weather impacts life and in this dire condition, people rely on communication, to organize relief and stay in touch with their loved ones. In such situations, cellular network infrastructure\footnote{We refer to cellular network infrastructure as infrastructure for the entirety of this document} might be affected due to power outage, link failures, etc. This urges us to look at Ad-hoc mode of communication, to offload major traffic partially or fully from the infrastructure, depending on the status of it.

We look into threefold approach, ranging from the case where the infrastructure is completely unavailable, to where it has ...


Religious Devices: A Survey Of Technologies Of Worship., Hugh Davies Mar 2019

Religious Devices: A Survey Of Technologies Of Worship., Hugh Davies

communication +1

Responding to the unannounced spiritual mysticism surrounding contemporary technologies, a religiosity present in the prayer-like devotion of social media piety to the cultish intensity surrounding each iPhone launch, this paper aims to dispel presumptions of the spiritual in opposition to the technological by surveying a range of media devices specifically developed for religious purposes. More than connecting scholarship in technology, media and religion, this survey recommends a new arc in the cultural examination of technology. As curious media artefacts, religious devices are independently worthy of study but they also offer a material past to the so-called “religion of Silicon Valley ...


Sequence Design Via Semidefinite Programming Relaxation And Randomized Projection, Dian Mo Mar 2019

Sequence Design Via Semidefinite Programming Relaxation And Randomized Projection, Dian Mo

Doctoral Dissertations

Wideband is a booming technology in the field of wireless communications. The receivers in wideband communication systems are expected to cover a very wide spectrum and adaptively extract the parts of interest. The literature has focused on mixing the input spectrum to baseband using a pseudorandom sequence modulation and recovering the received signals from linearly independent measurements by parallel branches to mitigate the pressures from required extreme high sampling frequency. However, a pseudorandom sequence provides no rejection for the strong interferers received together with weak signals from distant sources. The interferers cause significant distortion due to the nonlinearity of the ...


Energy Efficiency Of Computation In All-Spin Logic: Projections And Fundamental Limits, Zongya Chen Mar 2019

Energy Efficiency Of Computation In All-Spin Logic: Projections And Fundamental Limits, Zongya Chen

Masters Theses

Built with nanomagnets, a spintronic device called the all-spin logic (ASL) device carries information with only spin currents, resulting in a low power supply--10 mV. This voltage is 100 times smaller than the conventional CMOS devices (usually 0.8~1V). The potential for improved energy efficiency made possible by the low operating voltage of ASL makes it one of the most promising devices among its post-CMOS competitors.

The basic working principles of ASL device are introduced in this thesis and two complementary approaches to studying energy efficiency of computation are applied to a common set of ASL circuits: (1) a ...


Insar Simulations For Swot And Dual Frequency Processing For Topographic Measurements, Gerard Masalias Huguet Mar 2019

Insar Simulations For Swot And Dual Frequency Processing For Topographic Measurements, Gerard Masalias Huguet

Masters Theses

In Earth remote sensing precise characterization of the backscatter coefficient is important to extract valuable information about the observed target. A system that eliminates platform motion during near-nadir airborne observations is presented in this thesis, showing an improvement on the accuracy of measurements for a Ka- band scatterometer previously developed at Microwave Remote Sensing Laboratory (MIRSL). These very same results are used to simulate the reflectivity of such targets as seen from a spaceborne radar and estimate height errors based on mission-specific geometry. Finally, data collected from a dual-frequency airborne interferometer com- prised by the Ka-band system and an S-band ...


Source Data For "Tuning Charge Transport Dynamics Via Clustering Of Doping In Organic Semiconductor Thin Films", Connor J. Boyle, Meenakshi Upadhyaya, Dhandapani Venkataraman, Zlatan Aksamija, Michael Lu-Díaz Jan 2019

Source Data For "Tuning Charge Transport Dynamics Via Clustering Of Doping In Organic Semiconductor Thin Films", Connor J. Boyle, Meenakshi Upadhyaya, Dhandapani Venkataraman, Zlatan Aksamija, Michael Lu-Díaz

Data and Datasets

No abstract provided.