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Full-Text Articles in Engineering

Design Of Remote Datalogger Connection And Live Data Tweeting System, Zachary Wofford May 2019

Design Of Remote Datalogger Connection And Live Data Tweeting System, Zachary Wofford

Biological and Agricultural Engineering Undergraduate Honors Theses

Low-Impact Development (LID) is an attempt to sustainably respond to the potential hazards posed by urban expansion. Green roofs are an example of LID design meant to reduce the amount of runoff from storm events that are becoming more intense and less predictable while also providing insulation to buildings. LID has not yet been widely adopted as it is often a more expensive alternative to conventional infrastructure (Bowman et. al., 2009). However, its benefits are apparent. The University of Arkansas Honors College awarded a grant to research the large green roof atop Hillside Auditorium. One part of this grant is ...


Autonomous Boat Control Software Design Using Model-Based Systems Engineering, Noah Nelson May 2019

Autonomous Boat Control Software Design Using Model-Based Systems Engineering, Noah Nelson

Electrical Engineering Undergraduate Honors Theses

While there is considerable buzz about self-driving cars, self-driving boats are actually more fully developed. The Boat Hardware Control Platform Team was tasked with developing a fleet of small autonomous boats that travel to a destination while avoiding obstacles and staying in formation. The author’s specific task was to develop software used by the boats to detect obstacles and plan a route to a destination. This was done using a method inspired by self-driving cars, which shows promise, but is still being tested at the time of writing. The entire project incorporated model-based systems engineering, which proved to be ...


A Silicon Germanium Cmos Linear Voltage Regulator For Wireless Agricultural Applications, Aminta Naidili Castillo Robles May 2019

A Silicon Germanium Cmos Linear Voltage Regulator For Wireless Agricultural Applications, Aminta Naidili Castillo Robles

Theses and Dissertations

This thesis presents the design, simulation and test results of a silicon germanium (SiGe) complementary metal-oxide-semiconductor (CMOS) linear regulator. The objective of the circuit is to power other analog devices regardless of the load current and input voltage changes. The application of this regulator is to be part of a project developing a miniaturized semiconductor platform that can be inserted into stems of crops in order to measure data inside the plant and then send it wirelessly to the user. The linear regulator was designed on a BiCMOS SiGe 0.13µm which is a GlobalFoundries process. It has been tested ...


Short-Circuit Protection For Low-Voltage Dc Distribution Systems Based On Solid-State Circuit Breakers, Sharthak Munasib May 2017

Short-Circuit Protection For Low-Voltage Dc Distribution Systems Based On Solid-State Circuit Breakers, Sharthak Munasib

Theses and Dissertations

Proper short-circuit protection in dc distribution systems has provided an austere challenge to researchers as the development of commercially-viable equipment providing fast operation, coordination and reliability still continues. The objective of this thesis is to analyze issues associated with short-circuit protection of low-voltage dc (LVDC) distribution systems and propose a short-circuit protection methodology based on solid-state circuit breakers (SSCBs) that provides fault-current limiting (FCL). Simulation results for a simplified notional 1-kVdc distribution system, performed in MATLAB/SIMULINKTM, would be presented to illustrate that SSCB solutions based on reverse-blocking integrated gate-commutated thyristors (RB-IGCT) are feasible for low-voltage dc distribution systems but ...


Applications Of Krylov Subspace And Balanced Truncation Model Order Reduction In Power Systems, Sebastian Emanuel Garrido May 2017

Applications Of Krylov Subspace And Balanced Truncation Model Order Reduction In Power Systems, Sebastian Emanuel Garrido

Theses and Dissertations

Dynamic representations of power systems usually result in the order of hundreds or even thousands of buses. Therefore, reduction of these dynamic representations is convenient. Two applications of model order reduction in power systems are discussed in this thesis. First, Krylov subspace-based method is applied to the IEEE-123 Node Test Feeder in the context of distribution-level power systems simulation. Second, a Balanced Truncation-based model reduction is implemented in the 3-Machine 9-Bus system for designing a power system controller in the context of generation- and transmission-level power systems.

First, for the IEEE-123 Node Test Feeder, a two-sided Arnoldi algorithm is proposed ...


Channel Estimation Overhead Reduction For Downlink Fdd Massive Mimo Systems, Abderrahmane Mayouche Aug 2016

Channel Estimation Overhead Reduction For Downlink Fdd Massive Mimo Systems, Abderrahmane Mayouche

Theses and Dissertations

Massive multiple-input multiple-output (MIMO) is the concept of deploying a very large number of antennas at the base stations (BS) of cellular networks. Frequency-division duplexing (FDD) massive MIMO systems in the downlink (DL) suffer significantly from the channel estimation overhead. In this thesis, we propose a minimum mean square error (MMSE)-based channel estimation framework that exploits the spatial correlation between the antennas at the BS to reduce the latter overhead. We investigate how the number of antennas at the BS affects the channel estimation error through analytical and asymptotic analysis. In addition, we derive a lower bound on the ...


Design Of Smartseat Car Seat Safety System To Prevent Child Vehicular Heat Stroke, Alexis D. Lamott May 2016

Design Of Smartseat Car Seat Safety System To Prevent Child Vehicular Heat Stroke, Alexis D. Lamott

Electrical Engineering Undergraduate Honors Theses

Child vehicular heatstroke deaths continue to be a preventable accident seen yearly. As such, a proposed safety system has been designed to monitor environmental temperatures and weight in an infant seat, to alert guardians that a young child is at risk of child vehicular heatstroke death or serious heatstroke related injury. The SmartSeat system is comprised of three separate printed circuit boards that work in unison to form the overall system.


Reducing Multiple Access Interference In Broadband Multi-User Wireless Networks, Ali Nayef Alqatawneh Jul 2015

Reducing Multiple Access Interference In Broadband Multi-User Wireless Networks, Ali Nayef Alqatawneh

Theses and Dissertations

This dissertation is devoted to developing multiple access interference (MAI) reduction techniques for multi-carrier multi-user wireless communication networks.

In multi-carrier code division multiple access (MC-CDMA) systems, a full multipath diversity can be achieved by transmitting one symbol over multiple orthogonal subcarriers by means of spreading codes. However, in frequency selective fading channels, orthogonality among users can be destroyed leading to MAI. MAI represents the main obstacle to support large number of users in multi-user wireless systems. Consequently, MAI reduction becomes a main challenge when designing multi-carrier multi-user wireless networks. In this dissertation, first, we study MC-CDMA systems with different existing ...


Text-Independent Speaker Identification Using Statistical Learning, Alli Ayoola Ojutiku Jul 2015

Text-Independent Speaker Identification Using Statistical Learning, Alli Ayoola Ojutiku

Theses and Dissertations

The proliferation of voice-activated devices and systems and over-the-phone bank transactions has made our daily affairs much easier in recent times. The ease that these systems offer also call for a need for them to be fail-safe against impersonators. Due to the sensitive information that might be shred on these systems, it is imperative that security be an utmost concern during the development stages. Vital systems like these should incorporate a functionality of discriminating between the actual speaker and impersonators. That functionality is the focus of this thesis.

Several methods have been proposed to be used to achieve this system ...


Mobile Health Sensing With Smart Phones, Abby Logan Wise May 2015

Mobile Health Sensing With Smart Phones, Abby Logan Wise

Electrical Engineering Undergraduate Honors Theses

Depression is a serious mental condition affecting many Americans and people across the world. Postpartum depression is a form of depression affecting women who have recently gone through childbirth. Postpartum depression can have serious symptoms that may affect not only the mother, but her newborn as well. Early detection of these symptoms is of critical importance to the welfare of the mother and her child. Many medical professionals express the need for postpartum screening being that treatment has proven to be very effective. This project aims to make early symptom detection convenient and reliable for mothers with newborns. This will ...


Optimizing Performance And Scalability On Hybrid Mpsocs, Hongyuan Ding Dec 2014

Optimizing Performance And Scalability On Hybrid Mpsocs, Hongyuan Ding

Theses and Dissertations

Hardware accelerators are capable of achieving significant performance improvement. But design- ing hardware accelerators lacks the flexibility and the productivity. Combining hardware accelerators with multiprocessor system-on-chip (MPSoC) is an alternative way to balance the flexibility, the productivity, and the performance. However, without appropriate programming model it is still a challenge to achieve parallelism on a hybrid (MPSoC) with with both general-purpose processors and dedicated accelerators. Besides, increasing computation demands with limited power budget require more energy-efficient design without performance degradation in embedded systems and mobile computing platforms. Reconfigurable computing with emerging storage technologies is an alternative to enable the optimization ...


Electroencephalography(Eeg) Data Collection And Processing Through Machine Learning, Jayshree Desai Aug 2014

Electroencephalography(Eeg) Data Collection And Processing Through Machine Learning, Jayshree Desai

Theses and Dissertations

Machine learning methods are an excellent way for understanding the neural basis of human decision making. Some machine learning systems try to eradicate the need for human intuition in data analysis whereas others embrace a collective approach between humans and machines. The objective of this project is to collect Electroencephalography (EEG) signals through wireless sensors, and the process the collected signals through machine learning methods. The EEG data is collected using three EEG electrodes, each being the positive, negative and ground terminals respectively. Since the signal measures in the unit of micro-volts it needs to be amplified using amplifier circuit ...


Optimum Design Of Spectral Efficient Green Wireless Communications, Gang Wang Aug 2014

Optimum Design Of Spectral Efficient Green Wireless Communications, Gang Wang

Theses and Dissertations

This dissertation focuses on the optimum design of spectral efficient green wireless communications. Energy efficiency (EE), which is defined as the inverse of average energy required to successfully deliver one information bit from a source to its destination, and spectral efficiency (SE), which is defined as the average data rate per unit bandwidth, are two fundamental performance metrics of wireless communication systems. We study the optimum designs of a wide range of practical wireless communication systems that can either maximize EE, or SE, or achieve a balanced tradeoff between the two metrics. There are three objectives in this dissertation. First ...


A Solar-Powered And Multi-Tiered Mesh Node For A Portable In Situ Emergency Response System, Adam Matthews Dec 2013

A Solar-Powered And Multi-Tiered Mesh Node For A Portable In Situ Emergency Response System, Adam Matthews

Theses and Dissertations

The aftermath of a natural disaster is typically characterized by lack of a reliable medium for dissemination of information to survivors. Current state-of-the-art emergency response systems rely on satellite radio-enabled devices, but survivors, unlike first responders, do not have access to such devices. To mitigate this problem, we present PERPETUU a solar-powered portable GIS microserver. The microserver node can be deployed in a disaster scene, and can serve maps to survivors viewable on browsers of off-the-shelf mobile systems. A key innovation in the design of the PERPETUU node is a multi-tiered hardware architecture-the system combines a low-power micro-controller, a medium-power ...


Distortion-Tolerant Communications With Correlated Information, Ning Sun Dec 2013

Distortion-Tolerant Communications With Correlated Information, Ning Sun

Theses and Dissertations

This dissertation is devoted to the development of distortion-tolerant communication techniques by exploiting the spatial and/or temporal correlation in a broad range of wireless communication systems under various system configurations. Signals observed in wireless communication systems are often correlated in the spatial and/or temporal domains, and the correlation can be used to facilitate system designs and to improve system performance. First, the optimum

node density, i.e., the optimum number of nodes in a unit area, is identified by utilizing the spatial data correlation in the one- and two-dimensional wireless sensor networks (WSNs), under the

constraint of fixed ...


Reliability Analysis Of Social Networks, Kellie R. Schneider May 2013

Reliability Analysis Of Social Networks, Kellie R. Schneider

Theses and Dissertations

The primary focus of this dissertation is on the quantification of actor interaction and the dissemination of information through Social networks. Social networks have long been used to model the interactions between people in various Social and professional contexts. These networks allow for the explicit modeling of the complex interrelations between relevant individuals within an organization and the role they play in the decision making process. This dissertation considers Social networks represented as network flow models in which actors have the ability to provide some level of influence over other actors within the network. The models developed incorporate performance metrics ...


Design And Analysis Of An Adaptive Asynchronous System Architecture For Energy Efficiency, Brent Michael Hollosi Dec 2012

Design And Analysis Of An Adaptive Asynchronous System Architecture For Energy Efficiency, Brent Michael Hollosi

Theses and Dissertations

Power has become a critical design parameter for digital CMOS integrated circuits. With performance still garnering much concern, a central idea has emerged: minimizing power consumption while maintaining performance. The use of dynamic voltage scaling (DVS) with parallelism has shown to be an effective way of saving power while maintaining performance. However, the potency of DVS and parallelism in traditional, clocked synchronous systems is limited because of the strict timing requirements such systems must comply with. Delay-insensitive (DI) asynchronous systems have the potential to benefit more from these techniques due to their flexible timing requirements and high modularity. This dissertation ...


Energy And Spectral Efficient Wireless Communications, Guoqing Zhou Dec 2012

Energy And Spectral Efficient Wireless Communications, Guoqing Zhou

Theses and Dissertations

Energy and spectrum are two precious commodities for wireless communications. How to improve the energy and spectrum efficiency has become two critical issues for the designs of wireless communication systems. This dissertation is devoted to the development of energy and spectral efficient wireless communications. The developed techniques can be applied to a wide range of wireless communication systems, such as wireless sensor network (WSN) designed for structure health monitoring (SHM), medium access control (MAC) for multi-user systems, and cooperative spectrum sensing in cognitive radio systems.

First, to improve the energy efficiency in SHM WSN, a new ultra low power (ULP ...


Implementation Of Orthogonal Frequency Division Multiplexing With Fpga, Qi Hao Yang May 2012

Implementation Of Orthogonal Frequency Division Multiplexing With Fpga, Qi Hao Yang

Theses and Dissertations

In recent years, there have been dramatic shifts in cellular and telecommunication industries. As smartphones are dominating on the cellphone market, more and more people use these mobile devices to access internet either through third generation network or IEEE802.11 wireless local area network. Orthogonal frequency division multiplexing (OFDM) has been widely used in IEEE802.11 wireless local area network and fourth generation network. This paper will focus on the design and implementation of an Orthogonal Frequency Division Multiplexing system on field-programmable gate array (FPGA). The major components of an OFDM system include a modulator, an N-input inverse Fast Fourier ...


Mapping Device With Wireless Communication, Xiangyu Liu Dec 2011

Mapping Device With Wireless Communication, Xiangyu Liu

Electrical Engineering Undergraduate Honors Theses

Wireless communication is one of the most powerful communication methods that people use nowadays. The key advantage of wireless communications is that it can cover large distances without having to run any cables from one end to the other. Based on this advantage, wireless communication has many important applications, such as remote controls, cell phones, and global positioning system (GPS). This senior design project is developed to use wireless communication technology to map the geographic characteristics of an unknown place. It contains two wireless communication modules with Atmega1281 microprocessor, two robots with the 8051 microcontroller, six pairs of infrared transmitters ...


A Study On The Effect Of Random Placement And Orientation On The Resonance Of Multiple Split Ring Resonators, Michael Buscher Sep 2009

A Study On The Effect Of Random Placement And Orientation On The Resonance Of Multiple Split Ring Resonators, Michael Buscher

Electrical Engineering Undergraduate Honors Theses

This thesis project experimentally studies the effect of placing split-ring oscillators (SRR) in a non-periodic arrangment with random orientation. This is contrary to typical structures which are simulated as a single unit cell with a periodic boundry condition to emulate an infinite array of SSR's. Samples are measured using a near-field free-space measurement system with full Thru, Reflect, Line (TRL) calibration and the application of time domain gating. Results, in the form of scattering (S) parameters, are compared with previous measurments of periodic SRR structures in order to study the influence, if any, of periodicity in the frequency response ...


Computational Modeling Of The Internal Structure In The Breast, Jordan Greenlee May 2009

Computational Modeling Of The Internal Structure In The Breast, Jordan Greenlee

Electrical Engineering Undergraduate Honors Theses

Many researchers who are using microwave modality in the area of breast cancer detection employ oversimplified models of the internal structure of the breast. Use of engineered or biologically inaccurate models could render inaccurate results. Therefore, a mathematical biological model is implemented in this work and aims to bridge the gap between biologists and engineers. The results of the proposed breast duct model show that older women have smaller breast ducts leading to less dense breasts, which is in agreement with medical knowledge. Also, younger women have larger breast ducts leading to more dense breasts which are consistent with the ...


Preliminary Study Based On The Ddscat Software To Explore Increasing The Contrast Of Breast Tumors For Microwave Imaging, Rachel Megee May 2009

Preliminary Study Based On The Ddscat Software To Explore Increasing The Contrast Of Breast Tumors For Microwave Imaging, Rachel Megee

Electrical Engineering Undergraduate Honors Theses

Microwave technology is being researched for its capabilities to detect breast tumors less painfully and at earlier stages. It is necessary to have a large contrast between cancerous and healthy tissue when the microwaves are reflected off the breast tissue. To model the increasing contrast between cancerous breast tissue and healthy breast tissue, the DDSCAT code is investigated for its capabilities and analyzed for its accuracy in scattering calculations. The DDSCAT is used to model homogenous and inhomogeneous targets. Simulations of the scattering field by the homogeneous and inhomogeneous targets are conducted and compared to Mie theory calculations for accuracy ...