Digital Commons Network^™

Making The Graduate-Industry Connection, Mariesa Crow

Electrical and Computer Engineering Faculty Research & Creative Works

Many utilities are beginning to ramp up their recruiting and hiring efforts to attract bright young engineering graduates into the industry to replace the large numbers of engineers that have recently retired or will retire in the next few years. Unfortunately, the long drought in hiring brought on by the uncertainty of deregulation and the perspective that the industry is "old and conservative" has caused a mismatch in the interests of young engineers and the companies that want to hire them. in addition, the number of young people pursuing engineering degrees is decreasing as they become attracted to other lucrative …

Matched Filter Bound Of Wireless Systems Over Frequency Selective Channels With Receiver Timing Phase Offset, Jingxian Wu, Y. Rosa Zheng, Khaled Ben Letaief, Chengshan Xiao

Electrical and Computer Engineering Faculty Research & Creative Works

The sampler timing (phase) sensitivity of wireless communication systems is discussed in this paper. Based on the matched filter bound technique, a tight error performance bound is derived for systems experiencing frequency selective Rayleigh fading, with the receiver timing offset being quantified in the error performance expressions. With the error performance bound, the timing phase sensitivity of systems with both symbol spaced receivers and fractionally spaced receivers is analyzed. Simulation results show that the new bound can accurately predict the performance of practical communication systems suffering both frequency selective fading and timing phase offset.

Model For Estimating Radiated Emissions From A Printed Circuit Board With Attached Cables Due To Voltage-Driven Sources, Todd H. Hubing, Hwan-Woo Shim

Electrical and Computer Engineering Faculty Research & Creative Works

Common-mode currents induced on cables attached to printed circuit boards (PCBs) can be a significant source of unintentional radiated emissions. This paper develops a model for estimating the amount of common-mode cable current that can be induced by the signal voltage on microstrip trace structures or heatsinks on a PCB. The model employs static electric field solvers or closed-form expressions to estimate the effective self-capacitances of the board, trace, and/or heatsink. These capacitances are then used to determine the amplitude of an equivalent common-mode voltage source that drives the attached cables. The model shows that these voltage-driven common-mode cable currents …

Grouping Www Image Search Results By Novel Inhomogeneous Clustering Method, Gu Xu, Zhiwei Li, Mingjing Li, Wei-Ying Ma, Hong-Jiang Zhang

Mechanical and Aerospace Engineering Faculty Research & Creative Works

In this paper, a novel inhomogeneous clustering method is proposed for grouping web images. It is used to re-organize the search result of web image search engines into a hierarchical structure so that the users can conveniently browse the search result. This method takes into account various features associated with web images, and treats them in different ways. For the surrounding text extracted from the containing web pages, co-clustering approach is adopted; for low-level features of the image content and other features, one-way clustering approach is adopted. The clustering results of different approaches are combined together to produce the final …

Hierarchical Optimal Force-Position Control Of A Turning Process, B. Pandurangan, Robert G. Landers, S. N. Balakrishnan

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Machining process control technologies are currently not well integrated into machine tool controllers and, thus, servomechanism dynamics are often ignored when designing and implementing process controllers. In this brief, a hierarchical controller is developed that simultaneously regulates the servomechanism motions and cutting forces in a turning operation. The force process and servomechanism system are separated into high and low levels, respectively, in the hierarchy. The high-level goal is to maintain a constant cutting force to maximize productivity while not violating a spindle power constraint. This goal is systematically propagated to the lower level and combined with the low-level goal to …

Effect Of Control Plot Density, Control Plot Arrangement, And Assumption Of Random Or Fixed Effects On Nonreplicated Experiments For Germplasm Screening Using Spatial Models, Boi Sebolai, Jeffrey F. Pedersen, D. B. Marx, D. L. Boykin

Department of Agronomy and Horticulture: Faculty Publications

Early generation selection experiments typically involve several hundred to thousands of lines. Various systematic and statistical techniques have been developed to increase effectiveness and efficiencies in such experiments, including the development and application of spatial statistical models. In this study, mixed model equations were used to provide least squares means (LSMEANs) and best linear unbiased predictors (BLUPs) and compare selection effectiveness and efficiencies to observed (Y) and true values in simulated experiments varying in size (10 X 10, 20 X 20 and 30 X 30 grids), control plots densities (0, 5, 10, 20, and 50%), control plot arrangements (high, medium, …

Inherently Dangerous: The Potential For An Internet-Specific Standard Restricting Speech That Performs A Teaching Function, H. Brian Holland

Faculty Scholarship

Real or not, we perceive the convergence of several dangers-the physical threat of terrorism, both foreign and domestic; the economic threat of recession, corporate scandal, and globalization; and the social threat of new technology that connects, informs, exposes, and overwhelms us. At this moment, certain First Amendment protections are ripe for circumscription. The question, then, is whether our constitutional right of free speech is relative and conditional. The populist answer is yes. The legal answer is much more complicated.

To that end, this Article carries three goals. The first is to highlight parallel signals from the three branches of government …

Optimal And Hierarchical Formation Control For Uav, Xiaohua Wang, S. N. Balakrishnan

Mechanical and Aerospace Engineering Faculty Research & Creative Works

In this paper, optimal and hierarchical control concepts are investigated for cooperative formation flying of aircrafts. The airplanes are modeled as point mass and represented by double integrators. And all the planes are considered to be in a plane. For demonstration of the concepts, a task of forming a square from arbitrary initial conditions is presented to four airplanes. The final position that each airplane has to reach is unknown to them. The goal for the team is abstracted in the top layer. The system is modeled as a two layer hierarchical system in which the global information comes from …

Development And Characterization Of Antimicrobial Edible Films From Crawfish Chitosan, Kandasamy Nadarajah

LSU Doctoral Dissertations

Inherent antibacterial/antifungal properties and film-forming ability of chitosan make it ideal for use as a biodegradable antimicrobial packaging material. This study was attempted to develop antimicrobial films from crawfish chitosan. Traditional chitosan production involves: deproteinization (DP), demineralization (DM), decolorization (DC), and deacetylation (DA). Modification of chitosan production affects film properties. Effects of chitosan production protocols, film-casting solvents, and plasticizer contents on physicochemical, mechanical and antibacterial properties were investigated. Four chitosans were prepared from traditional (DPMCA) and modified processes [excluding either DP, DC or both DP and DC]. Chitosan (1%w/v) was dissolved in 1% acetic, ascorbic, citric, formic, lactic and/or malic …

Theoretical Investigation Of Quantum-Dot Avalanche Photodiodes For Mid-Infrared Applications, Sanjay Krishna, Oh-Hyun Kwon, Majeed M. Hayat

Electrical and Computer Engineering Faculty Research and Publications

A novel midinfrared sensor, called the quantum-dot avalanche photodiode (QDAP), is proposed which is expected to have improved signal-to-noise ratio (SNR) in the presence of Johnson noise over its quantum-dot (QD) counterpart. In the QDAP, an intersubband QD detector is coupled with a thin, low-noise GaAs avalanche layer through a tunnel barrier. The avalanche layer provides the necessary photocurrent gain required to overcome Johnson noise and nearly achieve the dark-current-limited SNR of the QD detector. In the proposed three-terminal device, the applied biases of the QD-detector and the avalanche-photodiode sections of the QDAP are controlled separately. This feature permits the …

Exponential Time Response In Analogue And Geiger Mode Avalanche Photodiodes, C. Groves, C. H. Tan, J. P.R. David, G. J. Rees, Majeed M. Hayat

Electrical and Computer Engineering Faculty Research and Publications

The mean avalanche current impulse response in an avalanche photodiode exhibits an initial transient and then grows or decays, above or below breakdown, at exponential rates which depend only on the probability distributions of the electron and hole ionization events. The process continues while the electric field profile remains unchanged by the applied bias or the evolving space charge. Below breakdown the distribution in the avalanche duration also exhibits an initial transient and then decays exponentially at the same rate as the mean current. Below breakdown the standard deviation in current decays exponentially at one half of the rate of …

Information-Theoretic Criterion For The Performance Of Single-Photon Avalanche Photodiodes, David A. Ramirez, Majeed M. Hayat, Sergio N. Torres, Bahaa E.A. Saleh, Malvin Carl Teich

Electrical and Computer Engineering Faculty Research and Publications

A channel-capacity metric is introduced for assessing the performance of single-photon avalanche photodiodes (SPADs) when used as detectors in laser communication systems. This metric is employed to theoretically optimize, with respect to the device structure and operating voltage, the performance of SPADs with simple InP or In/sub 0.52/Al/sub 0.48/As-InP heterojunction multiplication regions. As the multiplication-region width increases, an increase is predicted in both the peak and the full-width at half-maximum of the channel capacity curve versus the normalized excess voltage. Calculations also show the existence of an optimal In/sub 0.52/Al/sub 0.48/As-InP heterojunction multiplication region that maximizes the peak channel capacity …

Bone Engineering Of The Ulna Of Rabbit, Amanda Peter Hart

University of Kentucky Master's Theses

Repair of bone defects is a major challenge in orthopaedic surgery. Current bone graft treatments, including autografts, allografts and xenografts, have many limitations making it necessary to develop a biomaterial to be a bone graft substitute. One such biomaterial is bioactive resorbable silica-calcium phosphate nanocomposite (SCPC). SCPC was processed using a 3D rapid prototyping technique and sintered at different temperatures to create porous scaffolds. SEM analyses and mercury intrusion porosimetry showed SCPC to be highly porous with micro- and nanopores. BET analysis indicated that SCPC had high surface area. Mechanical testing demonstrated that SCPC had a compressive strength similar to …

Towards Full-Body Gesture Analysis And Recognition, Muthukumar B. Puranam

University of Kentucky Master's Theses

With computers being embedded in every walk of our life, there is an increasing demand forintuitive devices for human-computer interaction. As human beings use gestures as importantmeans of communication, devices based on gesture recognition systems will be effective for humaninteraction with computers. However, it is very important to keep such a system as non-intrusive aspossible, to reduce the limitations of interactions. Designing such non-intrusive, intuitive, camerabasedreal-time gesture recognition system has been an active area of research research in the fieldof computer vision.Gesture recognition invariably involves tracking body parts. We find many research works intracking body parts like eyes, lips, face …

Master Texture Space: An Efficient Encoding For Projectively Mapped Objects, David Guinnip

University of Kentucky Master's Theses

Projectively textured models are used in an increasingly large number of applicationsthat dynamically combine images with a simple geometric surface in a viewpoint dependentway. These models can provide visual fidelity while retaining the effects affordedby geometric approximation such as shadow casting and accurate perspective distortion.However, the number of stored views can be quite large and novel views must be synthesizedduring the rendering process because no single view may correctly texture the entireobject surface. This work introduces the Master Texture encoding and demonstrates thatthe encoding increases the utility of projectively textured objects by reducing render-timeoperations. Encoding involves three steps; 1) all …

Cycle-Up Of Multiple Rifting Event Models: How Long Does It Take To Reach A Steady State Stress?, Lokranjith K. Ravi

University of Kentucky Master's Theses

Many geological numerical models are initiated with a background stress state of zero. Often these numerical results are compared directly to geodetic data. Recent work (Kenner and Simons, 2004) has shown that modeled deformation rates can change as the model is cycled-up following repeated earthquakes or rifting events. In this study, we investigate model cycle-up in the context of time-dependent deformation following rifting during the 1975-1984 Krafla eruption in Iceland. We consider the number of rifting cycles required for complete cycle-up, variations in cycle-up time at different locations in the model, background stress magnitudes in fully cycled-up models, and errors …

Failure Mode Of The Weftless Bead And Evaluation Of Improved Continuous Single Wire Based Bead, Arun Kumar Doradla

University of Kentucky Master's Theses

Weftless Bead design has long been in existence and still used in many passenger car, bus, truck and agriculture tractors. The ideal bead design is a high strength flexible cable with minimal cross section and covered by rubberized nylon, rayon or steel wire side wall. The basic tire bead designs are weftless bead with rubberized ribbon of parallel wires of multiple wound layers and a continuous wire wound in sufficient number of loops to give the required strength. Weftless bead failures generally occur within about 5cm from the end of the overlapping parallel wire ribbon. The cause for this failure …

Nonlinear Transient Finite Element Simulations Of Beam Parametric Response Including Quadratic Damping, Satish N.R. Remala

University of Kentucky Master's Theses

Nonlinear parametric response of a flexible cantilever beam is simulated. In the simulations, lateral response of the beam due to an imposed axial harmonic base displacement excitation is calculated. The response frequency is approximately half the input frequency. The transient simulations include the assumption of damping proportional to the square of the velocity along the beam. Velocity-squared damping is realistic for situations in which fluid forces resisting the structural motion are significant. The commercial finite element software, ANSYS, is used to perform the simulations. A flexible method is developed and implemented in this work, based on the ANSYS Parametric Design …

Simulation Of Low-Re Flow Over A Modified Naca 4415 Airfoil With Oscillating Camber, Vamsidhar Katam

University of Kentucky Master's Theses

Recent interest in Micro Aerial Vehicles (MAVs) and Unmanned Aerial Vehicles (UAVs) have revived research on the performance of airfoils at relatively low Reynolds numbers. A common problem with low Reynolds number flow is that separation is almost inevitable without the application of some means of flow control, but understanding the nature of the separated flow is critical to designing an optimal flow control system. The current research presents results from a joint effort coupling numerical simulation and wind tunnel testing to investigate this flow regime. The primary airfoil for these studies is a modified 4415 with an adaptive actuator …

Implementation And Validation Of Fault Tolerant Control Of A Self-Bearing Motor Considering Open Coil Faults, Anand Ranganathan

University of Kentucky Master's Theses

Self-bearing motor is a magnetic actuator with both bearing and motoring functionality. This work implements and validates a decoupled and fault tolerant control algorithm for the Lorentz self bearing motor containing open phase faults. The goal of the algorithm is to achieve a stable bearing force and motoring torque even with coil faults. This work simulates many non-real-time fault tolerant control models based on the algorithm using simulink. Test cases are designed in simulink and tested on these models to arrive at the best model that could be implemented in dspace for real-time control. The responses of these simulations are …

Effects Of Stochastic (Random) Surface Roughness On Hydrodynamic Lubrication Of Deterministic Asperity, Prerit Vyas

University of Kentucky Master's Theses

In order to achieve enhanced and cost-effective performance of engineering components, Surface Engineering embraces traditional and innovative surface technologies which modify the surface properties of metallic and non-metallic engineering components for specific and sometime unique engineering purposes. The surface roughness of an engineered surface may be classified as: the random surface roughness which is a product of surface finishing and the deterministic surface roughness which is engineered to increase the lubrication characteristics of the hydro dynamically lubricated thrust ring. The effect of stochastic/random roughness can not be ignored when the roughness is of the same amplitude as that of fluid …

Statistical Analysis Of Injury Data And The Conceptual Design Of A Rollover Protective Structure For An All-Terrain Vehicle, Bhavana Parvathareddy

University of Kentucky Master's Theses

The rising statistics of fatal and non-fatal injuries involving an all-terrain vehicle has called for an analysis of the accumulated data from the past years. The analysis has led to the conclusion that in the past years, the fatal and non-fatal injuries have been rising rapidly in spite of the consent decrees which were brought into effect from 1988-1998 by the consumer product safety commission. A necessity to provide increased safety while riding an all-terrain vehicle is recognized. Rollover protective structures which were used with successful results in curbing the injuries on agricultural tractors have been identified as having a …

Modeling And Testing Ultra-Lightweight Thermoform-Stiffened Panels, Prathik Navalpakkam

University of Kentucky Master's Theses

Ultra-lightweight thermoformed stiffened structures are emerging as a viable option for spacecraft applications due to their advantage over inflatable structures. Although pressurization may be used for deployment, constant pressure is not required to maintain stiffness. However, thermoformed stiffening features are often locally nonlinear in their behavior under loading. This thesis has three aspects: 1) to understand stiffness properties of a thermoformed stiffened ultra-lightweight panel, 2) to develop finite element models using a phased-verification approach and 3) to verify panel response to dynamic loading. This thesis demonstrates that conventional static and dynamic testing principles can be applied to test ultra-lightweight thermoformed …

Exergy Based Method For Sustainable Energy Utilization Analysis Of A Net Shape Manufacturing System, Jayasankar Sankara

University of Kentucky Master's Theses

The approach advocated in this work implements energy/exergy analysis and indirectly an irreversibility evaluation to a continuous manufacturing process involving discrete net shape production of compact heat exchangers through a complex controlled atmosphere brazing (CAB) process. The system under consideration involves fifteen cells of a continuous ramp-up heating, melting, reactive flow, isothermal dwell, and rapid quench solidification processing sequence during a controlled atmosphere brazing of aluminum compact heat exchangers. Detailed mass, energy, and exergy balances were performed. The irreversibility sources were identified and the quality of energy utilization at different processing steps determined. It is demonstrated that advanced thermodynamics metrics …

Grouping Related Attributes, Santosh Dawara

Theses

Grouping objects that are described by attributes, or clustering is a central notion in data mining. On the other hand, similarity or relationships between attributes themselves is equally important but relatively unexplored. Such groups of attributes are also known as directories, concept hierarchies or topics depending on the underlying data domain. The similarities between the two problems of grouping objects and attributes might suggest that traditional clustering techniques are applicable. This thesis argues that traditional clustering techniques fail to adequately capture the solution we seek. It also explores domain-independent techniques for grouping attributes. The notion of similarity between attributes and …

Structural Advances For Pattern Discovery In Multi-Relational Databases, Juveria Kanodia

Theses

With ever-growing storage needs and drift towards very large relational storage settings, multi-relational data mining has become a prominent and pertinent field for discovering unique and interesting relational patterns. As a consequence, a whole suite of multi-relational data mining techniques is being developed. These techniques may either be extensions to the already existing single-table mining techniques or may be developed from scratch. For the traditionalists, single-table mining algorithms can be used to work on multi-relational settings by making inelegant and time consuming joins of all target relations. However, complex relational patterns cannot be expressed in a single-table format and thus, …

Can Foreign Aid Save Africa?, William Easterly

Clemens Lecture Series

No abstract provided.

Integration Of Micromachined Thermal Thermal Shear Stress Sensors With Microchannels - Design, Fabrication And Testing, Vinod Dilip Kulkarni

Theses

Rochester Institute of Technology, 2005 Includes bibliographical references (leaves 91-96) "The emerging picture of microvascular flow strongly suggests that local gradients in shear rate along the arteriole walls play an integral role in the ability of a microvascular network to regulate and modify blood flow. The methods to estimate shear stress from approximations of the velocity profiles determined by in vivo particle tracking experiments in the hamster and computational simulation are limited by assumptions made about the flow and experimental techniques. Right now, our ability to relate wall shear stress in microvessels to corresponding biological function is limited by our …

A Study To Determine If The Tech Prep Program At Dabney S. Lancaster Community College Has Academic Benefits Using Grade Point Average As A Predictor, Susan H. Carper

OTS Master's Level Projects & Papers

The problem of this study was to compare the grade point averages of students in the Tech Prep program at Dabney S. Lancaster Community College in Clifton Forge, Virginia, to students not in the Tech Prep program to determine if this career and technical education program has academic benefits.

The Demand For Industrial Technology And Technology Education Faculty Professors At United States Universities, Cleo Hicks Jr.

OTS Master's Level Projects & Papers

To guide this study, the following goals were developed: 1. Identify the positions available at the university level for professors of Technology Education and Industrial Technology; 2. Determine the demand of Industrial Technology faculty professor positions during the past five years; 3. Deter the demand of Technology Education faculty professor positions during the past five years; 4. Identify the different types of skills and requirements sought in these professions; 5. Determine the technical areas where the greatest need for faculty exists.