Engineering Commons^™

Development And Application Of A Design Flow For Photonic Integrated Circuits, Ifeanyi Achu

Electrical Engineering Theses and Dissertations

Silicon photonics allows for the fabrication of many optical elements on a single photonic integrated circuit (PIC). By taking advantage of the established foundry technology used in the CMOS and silicon’s high refractive index, high feature density manufacturing can be achieved in mass quantities. In CMOS fabrication, from conception of an electronic circuit to testing, the process of designing an electronic circuit is dictated by a design flow which has been developed over the course of decades. This flow includes circuit level design and simulation, layout of the circuit, layout and verification of the chip, fabrication, packaging, and testing. Given …

Void-Semiconductor Gaas Photonic Crystal Surface-Emitting Lasers By Epitaxial Regrowth And Single-Epitaxy Methods, Kevin James Reilly

Nanoscience and Microsystems ETDs

Monolithic semiconductor lasers including edge-emitting lasers (EELs) and vertical-cavity surface-emitting lasers (VCSELs) fail to realize simultaneous achievement of both high-power high-quality beams due to intrinsic limitations of their resonant cavity. Photonic crystal surface emitting lasers (PCSELs) address these structural limitations through employment of a two-dimensional photonic crystal (PC) cavity that creates feedback at a single wavelength for laterally scalable devices. This function of the PC allows PCSELs to power scale with area while maintaining single-mode emission required for diffraction-limited beams. In this way, PCSELs fulfill an industry demand for high-power high-quality lasing from a single chip.

Early PCSELs were fabricated …

Cyber-Secure Distributed Control Of Microgrids With Improved Communication And Control Protocols, Jee Won Choi

Mechanical Engineering ETDs

This dissertation proposes a cyber-secure distributed control of microgrids with improved communication and control protocols. The finite-time event-triggered control protocol for islanded AC and DC secondary control is introduced. For AC microgrids, the proposed strategy can effectively perform frequency restoration and voltage regulations while sharing the active and reactive power among the distributed generators (DGs) based on their power ratings. For DC microgrids, the proposed control protocol can provide accurate current sharing and critical bus voltage regulation. The finite-time control enables a system to reach a consensus in a finite period of time enhanced from asymptotic convergence. The event-triggered communication …

Towards Robust Channel Dynamics: Photoionization In Nitrogen And Air, Justin K. Smith

Electrical and Computer Engineering ETDs

In present photoionization models used in computational studies, there is a lack of experimental data and several assumptions pertaining to photo-electron production in the gas. It is widely accepted that wavelengths between 98 nm and 102.5 nm are the primary contributors to photoionization of oxygen in an air plasma. In air, the collisional kinetics of nitrogen provide the photons, which results in the ionization of oxygen. Photoionization rate measurements from a low current corona discharge in synthetic air mixtures are reported to provide new empirical data. In addition, this provides a method to estimate the scaling parameter w/a. Concurrently, vacuum …

Data-Driven Power System Stability Analysis And Control, Jian Xie

Electronic Theses and Dissertations, 2020-2023

In recent years, with the expansion of power system size, the increase of interconnection and the use of large-scale renewable energy, power system stability and safe operations have become more prominent, causing challenges to the normal operation of power grid. Traditional analysis rely on detailed models of the system. But for real power systems, the operating state of the system is variable, and the model-based analysis methods may not accurately reflect the real operating state of the system. Therefore, this dissertation is focused on data-driven stability analysis and control. First, a method for locating the oscillation source of multi-machine systems …

Leveraging Fpga Primitives To Improve Word Reconstruction During Netlist Reverse Engineering, Reilly Mckendrick, Corey Simpson, Brent Nelson, Jeffrey Goeders

Faculty Publications

While attempting to perform hardware trojan detection, or other low-level design analyses, it is often necessary to inspect and understand the gate-level netlist of an implemented hardware design. Unfortunately this process is challenging, as at the physical level, the design does not contain any hierarchy, net names, or word groupings. Previous work has shown how gate-level netlists can be analyzed to restore high-level circuit structures, including reconstructing multi-bit signals, which aids a user in understanding the behavior of the design. In this work we explore improvements to the word reconstruction process, specific to FPGA platforms. We demonstrate how hard-block primitives …

Distributed Detection In Energy Harvesting Wireless Sensor Networks, Ghazaleh Ardeshiri

Electronic Theses and Dissertations, 2020-2023

A conventional wireless sensor networks (WSN), consisting of sensors powered by nonrechargeable batteries, has a strictly limited lifetime. Energy harvesting (EH) from the environment is a promising solution to address the energy constraint problem in conventional WSNs, and to render these networks to self-sustainable networks with perpetual lifetimes. In EH-powered WSNs, where sensors are capable of harvesting and storing energy, power control is necessary to balance the rates of energy harvesting and energy consumption for data transmission. In addition, wireless communication channels change randomly in time due to fading. These together prompt the need for developing new power control strategies …

On-Board Artificial Intelligence For Failure Detection And Safe Trajectory Generation, Eduardo Morillo

Doctoral Dissertations and Master's Theses

The use of autonomous flight vehicles has recently increased due to their versatility and capability of carrying out different type of missions in a wide range of flight conditions. Adequate commanded trajectory generation and modification, as well as high-performance trajectory tracking control laws have been an essential focus of researchers given that integration into the National Air Space (NAS) is becoming a primary need. However, the operational safety of these systems can be easily affected if abnormal flight conditions are present, thereby compromising the nominal bounds of design of the system's flight envelop and trajectory following. This thesis focuses on …

Temporal Optical Activity And Chiral Time-Interfaces [Invited], Shixiong Yin, Yao-Ting Wang, Andrea Alù

Advanced Science Research Center

Time-interfaces, at which the optical properties of a medium undergo abrupt and spatially uniform changes, have attracted surging interest in optics and wave physics. In this work, we study wave scattering at time-interfaces involving chiral media. Dual to spatial interfaces involving chiral media, we show that a propagating wave is split upon a chiral time-interface into two orthogonal circular polarization waves oscillating at different frequencies. We formulate the temporal scattering boundary-value problem at such time-interfaces, and then demonstrate the effect of temporal optical activity through a chiral time-slab. The effect of material dispersion is also analyzed, highlighting interesting opportunities in …

Data-Driven Estimation Of The Power Grid Inertia With Increased Levels Of Renewable Generation Resources, Che Kai Chang

Theses - ALL

The thesis investigates methods for estimating inertia in systems at different levels of renewable energy penetrations. Estimating renewable generators' inertia is challenging because their structures differ from traditional generators. Moreover, the power generated from renewable energy resources is not stable, depending on weather conditions. When a power grid has a disturbance, photovoltaic inverter control influences a power grid inertia by different controllers, such as power factor and reactive power control, to bring a power grid back to a steady state. The changing reactive power impacts the frequency, which strongly relates to inertia and increases the inertia estimation problem.

Several papers …

Design Of Two Stage Bulk-Driven Operational Transconductance Amplifier (Ota) With A High Gain For Low Voltage Application, Pushkar N. Mishra

Theses - ALL

An Operational Transconductance Amplifier (further abbreviated as OTA) is a voltage controlled current source used to produce an output current proportional to the input voltage. A schematic architecture for a 180nm OTA is presented in this thesis with the goal of improving the open-loop gain for a 0.9V supply voltage with a rail-to-rail bulk-driven input stage. Results show an open loop gain 97.14 dB with a power consumption of 3.33uW. An OTA with over 90 dB open loop gain and lower power consumption is highly suitable for low-voltage applications. The slew rate of the OTA is 0.05V/uS with a unity-gain …

The Use Of Online Social Media Platforms By Tanzania Journalists To Produce And Disseminate Development News, Elisha Magolanga

Tanzania Journal of Engineering and Technology (TJET)

Advancement in Information and Communication Technologies (ICT) are revolutionizing Development Journalism (DJ) into an effective strategy for building competitive economies globally. However, many countries in Africa including Tanzania are slow in tapping potentials of ICT for development journalism. Digital penetration in the form of the Internet and social media are changing the way in which journalists are mobilizing and engaging communities in journalism practises, a key strategy for a competitive digitalised economy. This paper was guided by Development Communication Theory and Diffusion of Innovation Theory to explore the use of online social media by journalists in Tanzania to practice development …

Television White Space Based Broadband Network’S Coverage And Capex Performance For Rural Areas Connectivity In Tanzania, Moses Ismail

Tanzania Journal of Engineering and Technology (TJET)

This study compared the CAPEX requirements for a television white space (TVWS) based broadband network and that of deploying the UMTS based mobile broadband networks to deliver broadband connectivity in areas with sparse population which characterize most of Tanzania rural. Like many developing countries, Tanzania has low Internet penetration, with penetration of just over 46% when multiple subscriptions are taken into account. The affected communities are mostly rural due to low population densities which make deployment of the mobile broadband to be much expensive in terms of costs. This limits the economic development potential in these areas given that the …

Iot-Based Smart Fishing Gear For Sustainability Of The Tanzania Blue Economy, Abdi Abdalla

Tanzania Journal of Engineering and Technology (TJET)

The fishing industry engages many Tanzanians and is among the leading sectors of Blue Economy in the country. However, fishing practices are small-scale with poor and insufficient number of fishing facilities, hence limiting productivity and efficacy. Studies argue that the low level of technology currently used in the country could possibly be an impeding factor. Specifically, fishers use non interactive gears that cannot instantaneously update status and alert them whenever the gears are ready for collection. In such scenarios, fishers not only waste their time but also scarce resources such as fuel to facilitate trips to and from the fishing …

Development Of Directed Randomization For Discussing A Minimal Security Architecture, Henrique Oyama, Dominic Messina, Keshav Kasturi Rangan, Akkarakaran Francis Leonard, Kip Nieman, Helen Durand, Katie Tyrrell, Katrina Hinzman, Michael Williamson

Chemical Engineering and Materials Science Faculty Research Publications

Strategies for mitigating the impacts of cyberattacks on control systems using a control-oriented perspective have become of greater interest in recent years. Our group has contributed to this trend by developing several methods for detecting cyberattacks on process sensors, actuators, or both sensors and actuators simultaneously using an advanced optimization-based control strategy known as Lyapunov-based economic model predictive control (LEMPC). However, each technique comes with benefits and limitations, both with respect to one another and with respect to traditional information technology and computer science-type approaches to cybersecurity. An important question to ask, therefore, is what the goal should be of …

Red Comunitaria Bosachoque-Libre Ingeniería Al Servicio De La Brecha Digital Rural, Universidad De Cundinamarca Sede Fusagasugá, Ángela Patricia Arenas Amado, Eva Patricia Vásquez Gómez, Marcia Catalina Pulido Córdoba, Wilson Daniel Gordillo Ochoa

Ingeniería

En materia de conectividad y accesibilidad digital la pandemia por COVID – 19 expuso la exclusión digital en la cual se encuentran sumidos los territorios rurales de Colombia y el mundo. Pese a los ingentes esfuerzos del gobierno nacional a través de procesos institucionalizados para garantizar la inclusión de la tecnología en zonas rurales, no se logra una cobertura óptima, lo cual genera una afectación tecnológica, educativa y de salud pública para comunidades en situación de desventaja social, como es el caso de la ruralidad.
En este documento se muestran los resultados del trabajo de investigación llevado a cabo en …

Establishment And Mapping Of Heterogeneous Anomalies In Network Intrusion Datasets, Liam Riddell, Mohiuddin Ahmed, Paul Haskell-Dowland

Research outputs 2022 to 2026

Anomaly detection in the scope of network security aims to identify network instances for the unexpected and unique, with various security operations employing such techniques to facilitate effective threat detection. However, many systems have been designed based on the absolute mapping of attacks to one of three anomaly types (i.e. point, collective, or contextual), a strategy not supported by the recent findings of hybrid anomaly classifications. Given the growing usage of network anomaly detection and the implications of hybrid anomalies, we propose several heterogeneous anomaly types and provide an unsupervised approach for the automated mapping of network threats. Initial findings …

Wearable Sensors For Plants, Nafize Ishtiaque Hossain

Electrical Engineering Theses

This thesis reports PlantFit: a research and development project that is intended to develop wearable sensors for plants. Plants are responsible for providing food, fiber, fuel, and fodder to the society. To overcome the problem of a limited land base, a more efficient farming approach needs to be developed, and thus precision farming is required. Precision farming would entail personalized healthcare in plants. When the plant is under any stress, the productivity declines. Plants release phytohormones, also known as early responders, in response to these stressors. The key crop phytohormones that respond to environmental stresses include salicylic acid (SA), indole-3-acetic …

Effect On 360 Degree Video Streaming With Caching And Without Caching, Md Milon Uddin

Electrical Engineering Theses

People all around the world are becoming more and more accustomed to watching 360-degree videos, which offer a way to experience virtual reality. While watching videos, it enables users to view video scenes from any perspective. To reduce bandwidth costs and provide the video with less latency, 360-degree video caching at the edge server may be a smart option. A hypothetical 360-degree video streaming system can partition popular video materials into tiles that are cached at the edge server. This study uses the Least Recently Used (LRU) and Least Frequently Used (LFU) algorithms to accomplish video caching and suggest a …

Nuclear Power Plant In Las Vegas, Ryan W. Murray

Undergraduate Research Symposium Posters

This research focuses on the impact of a “Nuclear Power Plant in Las Vegas” or ‘NPP in LV’ for short. Nuclear power is clean, has no greenhouse gas emissions, and has a moderate cost of kilowatt hours. Las Vegas, or more specifically Clark County uses Gas power plants to produce a majority of their electricity. My project will show what a nuclear plant could do if built in the city of Las Vegas. What is a Nuclear power plant? The EIA’s definition is “A nuclear power plant uses the heat that a nuclear reactor produces to turn water into steam, …

Resiliency Of Levee-Protected Power Networks To Flooding In A Changing Climate Integrating Environmental Justice, Seyed Saeed Miraee-Ashtiani

Theses and Dissertations

Electric power system (EPS) is an integral part of infrastructure systems. Ensuring its resiliency to extreme weather events and natural hazards is crucial to protect the safety, economy and public health. Recorded and projected data show an increase in the frequency and severity of extreme weather events and natural hazards attributed to a changing climate. It is critical to ensure the integrity of the aging infrastructure systems and to promote environmental justice by shrinking the energy-equity gap to lower power outages in disadvantaged communities.

An important aspect is the resiliency interdependency of EPS to other critical infrastructure systems, an aspect …

Comparing Importance Of Knowledge And Professional Skill Areas For Engineering Programming Utilizing A Two Group Delphi Survey, John F. Hutton

Theses and Dissertations

All engineering careers require some level of programming proficiency. However, beginning programming classes are challenging for many students. Difficulties have been well-documented and contribute to high drop-out rates which prevent students from pursuing engineering. While many approaches have been tried to improve the performance of students and reduce the dropout rate, continued work is needed. This research seeks to re-examine what items are critical for programming education and how those might inform what is taught in introductory programming classes (CS1). Following trends coming from accreditation and academic boards on the importance of professional skills, we desire to rank knowledge and …

A Miniature And Low-Power Potentiostat For Integration With Wearable Sensors, Franci Franulovic

Electrical Engineering Theses

The potentiostat is an analytical device and an important part of an electrochemical instrument commonly used in electrochemical experiments to investigate chemical reaction mechanisms and other chemical phenomena. The ability to detect chemical phenomena can be useful for early disease detection. Nowadays conventional potentiostats are designed as benchtop instruments for use in laboratory environments. In contrast, a wearable potentiostat is designed to interface with wearable biochemical sensors for disease diagnostics. This thesis reports a wearable potentiostat that is designed for interfacing with a sensor array (eight to ten working electrodes). The system is battery-powered using lithium-ion batteries. The data is …

Autonomous Gyroscopic 2-Wheel Differential Robot, Haruka Kido, James Vrtis, Luke Anderson, Tarek Elderini

Electrical Engineering Student Publications

This paper demonstrates the implementation of an autonomous gyroscopic 2-wheel differential robot, including a forward and inverse kinematics simulation in MatLAB, a test hardware robot and programmed demonstration of a simple move forward and spin left motion, and a final configuration of a complete square path based on programming kinematics, gyroscopic speed responses, and remote-control functionality.

A Low-Cost, Low-Power, Scada Testbed Solution For Secure Remote Monitoring, Connor Berger

Symposium of Student Scholars

Similar to software application systems adopted by companies and businesses for product logging, payroll, human resources, Supervisory Control and Data Acquisition (SCADA) systems control the distributed processes with multiple components located on different machines that communicate and coordinate actions in order to appear as a single coherent system. SCADA systems severely lack the appropriate security and hack prevention measures. We propose a low cost, low power SCADA testbed solution for secure remote monitoring. The goal of this research is to implement and test the testbed’s security by emulating attack vectors on both hardware components and communication channels to probe the …

Small-Separation Speckle Contrast Optical Spectroscopy For Intraoperative Assessment Of Parathyroid Glands Viability During Thyroid Surgery, Connor Berger

Symposium of Student Scholars

The parathyroid glands (PTGs) are often damaged during thyroid surgeries due to a lack of methods identifying PTGs and assessing their viability. Damage to PTGs can cause hypocalcemia, a deficiency of calcium in the body. This complication can lead to detrimental consequences with economic burden. The surgeon’s current method of viability assessment is qualitative and subjective. Our technical solution is to employ an optical technique called speckle contrast optical spectroscopy (SCOS) that noninvasively quantifies the blood flow index (Db) of biological tissues at deep tissue levels (>1cm). The goal of this project is to verify SCOS at small source-detector-separation …

Six-Dimensional Single-Molecule Imaging With Isotropic Resolution Using A Multi-View Reflector Microscope, Oumeng Zhang, Zijian Guo, Yuanyuan He, Tingting Wu, Michael D. Vahey, Matthew D. Lew

Electrical & Systems Engineering Publications and Presentations

Imaging of both the positions and orientations of single fluorophores, termed single-molecule orientation-localization microscopy, is a powerful tool for the study of biochemical processes. However, the limited photon budget associated with single-molecule fluorescence makes high-dimensional imaging with isotropic, nanoscale spatial resolution a formidable challenge. Here we realize a radially and azimuthally polarized multi-view reflector (raMVR) microscope for the imaging of the three-dimensional (3D) positions and 3D orientations of single molecules, with precisions of 10.9 nm and 2.0° over a 1.5-μm depth range. The raMVR microscope achieves 6D super-resolution imaging of Nile red molecules transiently bound to lipid-coated spheres, accurately resolving …

Study Of Carbon Nanotube Embedded Honey As A Resistive Switching Material, Md Mehedi Hasan Tanim, Brandon Sueoka, Zhigang Xiao, Kuan Yew Cheong, Feng Zhao

Electrical and Computer Engineering Faculty Research & Creative Works

In this paper, natural organic honey embedded with carbon nanotubes (CNTs) was studied as a resistive switching material for biodegradable nonvolatile memory in emerging neuromorphic systems. CNTs were dispersed in a honey-water solution with the concentration of 0.2 wt.% CNT and 30 wt.% honey. The final honey-CNT-water mixture was spin-coated and dried into a thin film sandwiched in between Cu bottom electrode and Al top electrode to form a honey-CNT based resistive switching memory (RSM). Surface morphology, electrical characteristics and current conduction mechanism were investigated. The results show that although CNTs formed agglomerations in the dried honey-CNT film, both switching …

A Robust Platform For Mobile Robotics Teaching And Developing Using Arduino’S Integrated Development Environment (Ide) For Programming The Arduino Mega 2560, Sajjad Alhassan

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

In light of the rapid pace at which development happens with modern technology, mobile robots play an important role in our daily lives. This is due to their great importance in facilitating the affairs of life in various economic, commercial, industrial, scientific, and many other fields. In this research and project, we have restructured the microcontroller and system for one of the mobile robots (CEENBOT) that was designed by the University of Nebraska and replaced it with an Arduino Mega 2560.

The purpose of using the Arduino Mega 2560 robot is to provide alternative programming for the CEENBOT platform to …

An Ultrasensitive Bacterial Detection Platform For Culture-Free Diagnosis Of Infections, Xuyang Shi

ETD Archive

The current methods of the diagnosis of bloodstream infections are based on bacterial culture growth, a process that requires considerable time, e.g., 12-16 hours, to obtain a result. This long wait time for the result creates many problems, including the generation of multi-drug resistant organisms (MDROs). At the same time, infected bloodstream usually contains a very low concentration of bacteria, i.e., lower than 5 CFU/mL. The long diagnosis time and the extremely low concentration of bacteria in the infected bloodstream make such infections difficult to diagnose. Here, we demonstrate a culture-free approach for the diagnosis of bloodstream infections using a …