Engineering Commons^™

Mysteries And Heroes: Using Imaginative Education To Engage Middle School Learners In Engineering, Lucy Mcauliffe, Glenn W. Ellis, Sonia Katrin Ellis, Isabel Huff, Beth Mcginnis-Cavanaugh

Engineering: Faculty Publications

This paper examines the use of cognitive tools described in Imaginative Education (IE) in a middle school level engineering education project, Talk to Me. Developed by Kieran Egan, IE proposes five different levels of understandings, or ways of seeing and structuring the world, that develop at different cognitive and linguistic stages. The use of cognitive tools that assist learners with different understandings, such as narrative, engages these learners in a way that allows them to learn concepts more deeply. Talk to Me is aimed at middle school learners, primarily female students, in order to increase engagement from an early level …

Simulation And Control Of A Quadrotor Unmanned Aerial Vehicle, Michael David Schmidt

University of Kentucky Master's Theses

The ANGEL project (Aerial Network Guided Electronic Lookout) takes a systems engineering approach to the design, development, testing and implementation of a quadrotor unmanned aerial vehicle. Many current research endeavors into the field of quadrotors for use as unmanned vehicles do not utilize the broad systems approach to design and implementation. These other projects use pre-fabricated quadrotor platforms and a series of external sensors in a mock environment that is unfeasible for real world use. The ANGEL system was designed specifically for use in a combat theater where robustness and ease of control are paramount. A complete simulation model of …

Modeling And Optimization To Evaluate Sustainability Performance Of Customizable Product Service Systems, Ken Harsha Tilakaratne Wijekoon

University of Kentucky Master's Theses

The aim of this thesis is to present a new methodology to evaluate and optimize sustainability of customizable product-service systems while ensuring economic, environmental and societal constraints are also satisfied. Activities across the total product lifecycle are considered to develop a model that evaluates closed-loop flow, while being monitored through the growth, maturity and decline stages of the product to provide a comprehensive analysis. A novel method to evaluate the customer satisfaction is also presented. The research considers a modular product where customization can be achieved by selecting from alternatives while ensuring the compatibility between these alternatives. A manufacturer will …

Developing A Time And Motion Study For A Lean Healthcare Environment, Michael Winston Patton Jr.

University of Kentucky Master's Theses

This thesis outlines the development of a standard methodology for performing a time and motion study in a lean healthcare environment. Time and motion studies have been used in healthcare environments in the past, however they have nearly all been exclusive to a particular healthcare enterprise. To develop the time and motion study methodology, a study was designed to examine how resident doctors spend their time. This study was performed in response to coming changes in the work hours for all residents. Once the methodology was developed, trial observations were conducted. The data from these observations was analyzed to determine …

Capacitor Switching Transient Modeling And Analysis On An Electrical Utility Distribution System Using Simulink Software, Durga Bhavani Mupparty

University of Kentucky Master's Theses

The quality of electric power has been a constant topic of study, mainly because inherent problems to it can bring great economic losses in industrial processes. Among the factors that affect power quality, those related to transients originated from capacitor bank switching in the primary distribution systems must be highlighted. In this thesis, the characteristics of the transients resulting from the switching of utility capacitor banks are analyzed, as well as factors that influence there intensities. A practical application of synchronous closing to reduce capacitor bank switching transients is presented. A model that represents a real distribution system 12.47kV from …

Synthesis And Characterization Of P-Type Copper Indium Diselenide (Cis) Nanowires Embedded In Porous Alumina Templates, Sri Harsha Moturu

University of Kentucky Master's Theses

This work focuses on a simple template assisted approach for fabricating I-III-VI semiconductor nanowire arrays. Vertically aligned nanowires of p-CIS of controllable diameter and thickness are electrodeposited, from an acidic electrolyte solution, inside porous aluminum templates using a three electrode set up with saturated calomel electrode as the reference. AAO template over ITO-glass was used as starting template for the device fabrication. The deposited CIS is annealed at different temperatures in a reducing environment (95% Ar+ 5% H₂) for 30 minutes. X-ray diffraction of the nanowires showed nanocrystalline cubic phase structures with a strong orientation in the <112> direction. …

Gaze Estimation Using Sclera And Iris Extraction, Prashanth Rao Periketi

University of Kentucky Master's Theses

Tracking gaze of an individual provides important information in understanding the behavior of that person. Gaze tracking has been widely used in a variety of applications from tracking consumers gaze fixation on advertisements, controlling human-computer devices, to understanding behaviors of patients with various types of visual and/or neurological disorders such as autism. Gaze pattern can be identified using different methods but most of them require the use of specialized equipments which can be prohibitively expensive for some applications. In this dissertation, we investigate the possibility of using sclera and iris regions captured in a webcam sequence to estimate gaze pattern. …

Influence Of Tissue Absorption And Scattering On Diffuse Correlation Spectroscopy Blood Flow Measurements, Daniel Irwin

University of Kentucky Master's Theses

This investigation evaluates the influences of optical property assumptions on nearinfrared diffuse correlation spectroscopy (DCS) flow index measurements. Independent variation is induced in optical properties, absorption coefficient (μ_a) and reduced scattering coefficient (μ_s’), of liquid phantoms with concurrent measurements of flow indices. A hybrid instrument is incorporated consisting of a dual-wavelength (785 and 830 nm) DCS flow device to obtain flow indices and a frequency-domain tissue-oximeter for optical properties. Flow indices are calculated with measured μ_a and μ_s’ or assumed constant μ_a and μ_s’. Inaccurate μ_s’ assumptions produced …

Compact Vision System For Monitoring Of 3d Weld Pool Surface In Pipe Welding, Alexander Phillip Maroudis

University of Kentucky Master's Theses

Human welders have long been able to monitor a weld pool and adjust welding parameters accordingly. Automated welding robots can provide consistent movement during the welding process, but lack the ability to monitor the weld pool. A vision system attached to the welding robot could provide a way to monitor the weld pool substantially faster than a human being. Previous vision systems to monitor weld pool surfaces have been developed, but their uses are limited since the system is fixed in place. The compact vision system developed in this research attaches directly to the welding torch, which provides no limitations …

Strength And Erodability Of South Carolina Soils For Embankment Construction, Ke Zhou

Theses and Dissertations

When a particular soil from a borrow pit is being used to construct a road embankment, it is important that the strength and erodibility characteristics are known to ensure the embankment has sufficient load capacity and is resistant to erosion by rain or flooding. To evaluate the borrow pit material’s strength and erodibility characteristics, forty five-gallon buckets of soils were collected from fourteen borrow pits in South Carolina. Three buckets were collected at three different locations within each pit.

Fifteen sets of direct shear tests were performed on the selected fifteen buckets of soils. There are six buckets of soils …

Design And Analysis Of Macro Switched Impedance Motors, Weston C. Johnson

Theses and Dissertations--Electrical and Computer Engineering

For present day global economies energy use is the single most important criteria determining a nation’s wealth and sustainability. The global energy needs are met primarily by fossil fuels which are of finite supply. One means to extend the life span of the fossil fuel reserves has been to improve the efficiency of existing systems including generation, storage, usage etc., as a means of conservation. This dissertation investigates a motor technology that promises to complement existing conservation techniques.

Given advances in high voltage power semiconductors, manufacturing techniques and materials research this dissertation evaluates the potential of the switched impedance motor …

Improved Line Outage Detection Using Synchrophasor Measurements, Nick Mahoney

All Theses

The recent advent of synchronized phasor measurements has allowed a power system to be more readily observable. In fact, when multiple buses are observed, applications that were never before possible become a reality. One such application is the detection of line outages in remote or unobserved parts of the system. Two such methods of line outage detection are examined. First, principal component analysis is used to show that highly accurate line outage detection is possible. Using concepts similar to principal component analysis, a novel line outage detection algorithm is developed. Lastly, the efficacy of the novel line outage detection algorithm …

On The Performance Limits Of Cognitive Mimo Channels, Sami Akin, M. Cenk Gursoy

Department of Electrical and Computer Engineering: Faculty Publications

In this paper, throughput of cognitive multiple-input multiple-output (MIMO) systems operating under quality-of service (QoS) constraints is studied. It is assumed that transmission power and the covariance of the input signal vector are varied depending on the sensed activities of primary users in the system. Considering the reliability of the transmission and channel sensing results, a state-transition model is provided. Effective capacity is determined, and expressions for the first and second derivatives of the effective capacity are obtained at SNR = 0. The minimum bit energy requirements in the presence of QoS limitations are identified. Numerical results are provided.

Energy-Efficient Feedback Tracking On Embedded Smart Cameras By Hardware-Level Optimization, Mauricio Casares, Senem Velipasalar, Paolo Santinelli, Rita Cucchiara, Reggio Emilia, Andrea Prati

Department of Electrical and Computer Engineering: Faculty Publications

Embedded systems have limited processing power, memory and energy. When camera sensors are added to an embedded system, the problem of limited resources becomes even more pronounced. In this paper, we introduce two methodologies to increase the energy-efficiency and battery-life of an embedded smart camera by hardware-level operations when performing object detection and tracking. The CITRIC platform is employed as our embedded smart camera. First, down-sampling is performed at hardware level on the micro-controller of the image sensor rather than performing software-level down-sampling at the main microprocessor of the camera board. In addition, instead of performing object detection and tracking …

Risk-Based Failure Mode And Effect Analysis For Wind Turbines (Rb-Fmea), Salman Kahrobaee, Sohrab Asgarpoor

Department of Electrical and Computer Engineering: Faculty Publications

Failure Mode and Effect Analysis (FMEA) has already been used as a qualitative measure for identifying failure modes and causes, in order to mitigate the effects of failure in different sectors of power systems. This paper presents a quantitative approach called Risk-Based-FMEA, based on the failure probabilities and incurred failure costs instead of rating scales. As a case study, this approach has been applied to a direct drive wind turbine. The results show that the definition of failure modes priorities based on their contribution to the total failure cost of the wind turbine is more realistic and practical than the …

Series-Connected Self-Reconfigurable Multicell Battery, Taesic Kim, Wei Qiao, Liyan Qu

Department of Electrical and Computer Engineering: Faculty Publications

This paper proposes a novel series-connected, self-reconfigurable, multi-cell battery design. A new cell switching circuit topology is proposed and implemented by using high efficiency semiconductor devices for dynamic configuration of the multi-cell battery. Each cell in the battery only uses two switches to fully control its operation independently. The proposed design can maximally utilize the battery’s capacity and is tolerant to failures of single or multiple cells. These prolong the operating time and lifespan and enhance the reliability of the battery system. By using the proposed design, additional monitoring, control, protection and optimization functions can be readily added to each …

A Dual-Network Testbed For Wireless Sensor Applications, Jedrzej Kowalczuk, Mehmet C. Vuran, Lance C. Pérez

Department of Electrical and Computer Engineering: Faculty Publications

A dual-network Cyber-physical Networking (CPN) testbed developed at the University of Nebraska-Lincoln is described. The CPN testbed consists of two geographically disparate wireless sensor networks connected by a traditional TCP/IP network and enables peer-to-peer communication between each sensor in the network. The functionality of the testbed is enhanced by a range of software tools that support remote programming and network monitoring, and real-time visualization of sensor data. The resulting architecture supports easy deployment and evaluation of applications for both traditional and interconnected wireless sensor networks. To demonstrate the features of this testbed, a novel ping application was developed and deployed …

Analysis Of The Accuracy-Latency-Energy Tradeoff For Wireless Embedded Camera Networks, Alvaro Pinto, Zhe Zhang, Xin Dong, Senem Velipasalar, Mehmet C. Vuran, M. Cenk Gursoy

Department of Electrical and Computer Engineering: Faculty Publications

Wireless embedded smart cameras provide flexibility in camera deployment in terms of the locations and number of the cameras. However, these battery-powered embedded vision sensors have very limited energy, memory, and processing power. Energy consumption and latency are two major concerns in wireless embedded camera networks. In multi-camera tracking applications, the amount of data exchanged between cameras has an effect on the tracking accuracy, the energy consumption of the camera nodes and the latency. In this paper, we provide a detailed quantitative analysis of the accuracy-latency-energy tradeoff for overlapping and non-overlapping camera setups when different-sized data packets are transferred in …

Channel Coding Over Multiple Coherence Blocks With Queueing Constraints, Deli Qiao, M. Cenk Gursoy, Senem Velipasalar

Department of Electrical and Computer Engineering: Faculty Publications

This paper investigates the performance of wireless systems that employ finite-blocklength channel codes for transmission and operate under queueing constraints in the form of limitations on buffer overflow probabilities. A block fading model, in which fading stays constant in each coherence block and change independently between blocks, is considered. It is assumed that channel coding is performed over multiple coherence blocks. An approximate lower bound on the transmission rate is obtained from Feintein’s Lemma. This lower bound is considered as the service rate and is incorporated into the effective capacity formulation, which characterizes the maximum constant arrival rate that can …

On The Effective Capacity Of Two-Hop Communication Systems, Deli Qiao, M. Cenk Gursoy, Senem Velipasalar

Department of Electrical and Computer Engineering: Faculty Publications

In this paper, two-hop communication between a source and a destination with the aid of an intermediate relay node is considered. Both the source and intermediate relay node are assumed to operate under statistical quality of service (QoS) constraints imposed as limitations on the buffer overflow probabilities. It is further assumed that the nodes send the information at fixed power levels and have perfect channel side information. In this scenario, the maximum constant arrival rates that can be supported by this two-hop link are characterized by finding the effective capacity. Through this analysis, the impact upon the throughput of having …

Support Vector Machine-Based Short-Term Wind Power Forecasting, Jianwu Zeng, Wei Qiao

Department of Electrical and Computer Engineering: Faculty Publications

This paper proposes a support vector machine (SVM)-based statistical model for wind power forecasting (WPF). Instead of predicting wind power directly, the proposed model first predicts the wind speed, which is then used to predict the wind power by using the power-wind speed characteristics of the wind turbine generators. Simulation studies are carried out to validate the proposed model for very short-term and short term WPF by using the data obtained from the National Renewable Energy Laboratory (NREL). Results show that the proposed model is accurate for very short-term and short-term WPF and outperforms the persistence model as well as …

An Achievable Rate Region For Imperfectly-Known Two-Way Relay Fading Channels, Junwei Zhang, M. Cenk Gursoy

Department of Electrical and Computer Engineering: Faculty Publications

In this paper, achievable rates and resource allocation strategies for imperfectly known two-way relay fading channels are studied. Decode-and-forward (DF) relaying is considered. It is assumed that communication starts with the network training phase in which the users and the relay estimate the fading coefficients, albeit imperfectly. Subsequently, data transmission is performed in multiple-access and broadcast phases. In both phases, achievable rate regions are identified by treating the terms that arise due to channel estimation errors and imperfect interference cancellation as Gaussian distributed noise components. The achievable rate region of the two-way relay channel is given by the intersection of …

Energy-Efficient Foreground Object Detection On Embedded Smart Cameras By Hardware-Level Operations, Mauricio Casares, Paolo Santinelli, Senem Velipasalar, Andrea Prati, Rita Cucchiara

Department of Electrical and Computer Engineering: Faculty Publications

Embedded smart cameras have limited processing power, memory and energy. In this paper, we introduce two methodologies to increase the energy-efficiency and the battery-life of an embedded smart camera by hardware level operations when performing foreground object detection. We use the CITRIC platform as our embedded smart camera. We first perform down-sampling at hardware level on the micro-controller of the image sensor rather than performing software-level down-sampling at the main microprocessor of the camera board. In addition, we crop an image frame at hardware level by using the HREF and VSYNC signals at the micro-controller of the image sensor to …

On The Interplay Between Channel Sensing And Estimation In Cognitive Radio Systems, M. Cenk Gursoy, Sinan Gezici Sinan Gezici

Department of Electrical and Computer Engineering: Faculty Publications

Cognitive radio transmissions in the presence of channel uncertainty are considered. In practical scenarios, cognitive secondary users need to perform both channel sensing in order to identify whether the channel is being occupied by the primary users or not, and also channel estimation in order to learn the channel fading coefficients. Generally, errors occur in both channel sensing and estimation, and this leads to a coupling between the two. More specifically, imperfect sensing affects both the structure and the performance of channel estimation schemes. With this motivation, the interactions between channel sensing and estimation are studied in this paper. In …

Location Cheating: A Security Challenge To Location-Based Social Network Services, Wenbo He, Xue Liu, Mai Ren

Department of Electrical and Computer Engineering: Faculty Publications

Location-based mobile social network services such as foursquare and Gowalla have grown exponentially over the past several years. These location-based services utilize the geographical position to enrich user experiences in a variety of contexts, including location-based searching and location-based mobile advertising. To attract more users, the location-based mobile social network services provide real-world rewards to the user, when a user checks in at a certain venue or location. This gives incentives for users to cheat on their locations. In this paper, we investigate the threat of location cheating attacks, find the root cause of the vulnerability, and outline the possible …

A Current-Sensorless Mppt Quasi-Double-Boost Converter For Pv Systems, Christopher J. Lohmeier, Jianwu Zeng, Wei Qiao, Liyan Qu, Jerry L. Hudgins

Department of Electrical and Computer Engineering: Faculty Publications

This paper proposes a current-sensorless maximum power point tracking (MPPT) quasi-double-boost converter for photovoltaic (PV) systems. Instead of using sensors, the output current of the PV system is obtained from the measured voltage ripple in the input capacitor of the DC-DC converter. The estimated current is used by a hill-climbing (HC) MPPT algorithm to determine the optimal duty ratio for controlling the DC-DC converter. The operating principle, theoretical analysis, and design guidelines of the quasi-double-boost converter are provided in the paper. Simulation studies are carried out in MATLAB Simulink by using real solar radiation data obtained from the National Renewable …

Effective Capacity Region And Optimal Power Control For Fading Broadcast Channels, Deli Qiao, M. Cenk Gursoy, Senem Velipasalar

Department of Electrical and Computer Engineering: Faculty Publications

Transmission over fading broadcast channels in the presence of quality of service (QoS) constraints is studied. Effective capacity, which provides the maximum constant arrival rate that a given service process can support while satisfying statistical QoS constraints, is employed as the performance metric. The effective capacity region achieved with superposition coding and successive interference cancellation is identified and is shown to be convex. Subsequently, optimal power control policies that achieve the boundary points of the effective capacity region are investigated, and an algorithm for the numerical computation of the optimal power adaptation schemes for the two-user case is provided. Additionally, …

A Hybrid Battery Model Capable Of Capturing Dynamic Circuit Characteristics And Nonlinear Capacity Effects, Taesic Kim, Wei Qiao

Department of Electrical and Computer Engineering: Faculty Publications

A high-fidelity battery model capable of accurately predicting battery performance is required for proper design and operation of battery-powered systems. However, the existing battery models have at least one of the following drawbacks: 1) requiring intensive computation due to high complexity; 2) not applicable for electrical circuit design and simulation; and 3) not capable of accurately capturing the state of charge (SOC) and predicting run time of the battery due to neglecting the nonlinear capacity effects. This paper proposes a novel hybrid battery model, which takes the advantages of an electrical circuit battery model to accurately predicting the dynamic circuit …

Wide-Area Multi-Object Tracking With Non-Overlapping Camera Views, Youlu Wang, Senem Velipasalar, M. Cenk Gursoy

Department of Electrical and Computer Engineering: Faculty Publications

We present a system for wide-area multi-object tracking across disjoint camera views. We employ a probabilistic Petri Net-based approach to account for the uncertainties of the vision algorithms (such as unreliable background subtraction, and tracking failure) and to incorporate the available domain knowledge. We combine appearance features of objects as well as the travel-time evidence for target matching and consistent labeling across disjoint camera views. 3D color histogram, Histogram of Oriented Gradients, object size and aspect ratio are used as the appearance features. The distribution of the travel time is modeled by a Gaussian Mixture Model. By incorporating the domain …

Bearing Fault Detection For Direct-Drive Wind Turbines Via Stator Current Spectrum Analysis, Xiang Gong, Wei Qiao

Department of Electrical and Computer Engineering: Faculty Publications

Bearing faults constitute a significant portion of all faults in wind turbine generators (WTGs). Current-based bearing fault detection has significant advantages over traditional vibration-based methods in terms of cost, implementation, and system reliability. This paper proposes a method based on stator current power spectral density (PSD) analysis for bearing fault detection of direct-drive WTGs. In the proposed method, appropriate interpolation/up-sampling and down-sampling algorithms are designed to convert the variable fundamental frequency of the stator current to a fixed frequency according to the estimated fundamental speed of the WTG. Consequently, the characteristic frequencies of bearing faults can be clearly identified form …