Engineering Commons^™

A 1x2 Adaptive Optical Splitter Based On Opto-Vlsi Processor, Haithem Mustafa, Feng Xiao, Kamal Alameh

Research outputs pre 2011

A 1×2 adaptive optical splitter structure is proposed and experimentally demonstrated. The 1×2 adaptive optical splitter structure is based on Opto-VLSI in conjunction with 4-f imaging system. An Opto-VLSI processor is software driven and capable of splitting an optical beam into different directions when a multicasting phase hologram is uploaded. An input optical signal launched into an input optical fiber port is split and coupled into two output optical fiber ports with arbitrary splitting ratios over a wavelength range exceeding 50 nm.

High-Performance Thin-Film Garnet Materials For Magneto-Optic And Nanophotonic Applications, Mikhail Vasiliev, Mohammad Nur E Alam, Viacheslav Kotov, Kamal Alameh

Research outputs pre 2011

Since the 1960's, Magneto-optic (MO) garnet materials have been studied extensively. These materials can possess world-record MO performance characteristics in terms of Faraday rotation and optical quality. Among the rear-earth-doped garnets, the Bi-substituted iron garnet is the best candidate for use as a functional material in different integrated-optics, imaging/image processing applications and also in forward-looking applications e.g. the design of metamaterials with non-reciprocal properties. We have established a set of technologies for fabricating ferrimagnetic garnet films of type (BiDy)3(FeGa)5O12 and also garnet-oxide nanocomposite (BiDy)3(FeGa)5O12 : Bi2O3 layers possessing record-high MO quality across the visible spectral range using RF-magnetron sputtering and …

Design Of High-Sensitivity Plasmonics-Assisted Gaas Metal-Semiconductor-Metal Photodetectors, Ayman Karar, Narottam Das, Chee Leong Tan, Kamal Alameh, Yong Lee

Research outputs pre 2011

In this paper, we use the finite difference timedomain (FDTD) method to optimize the light absorption of an ultrafast plasmonic GaAs metal-semiconductor-metal photodetector (MSM-PD) employing metal nano-gratings. The MSM-PD is optimized geometrically, leading to improved light absorption near the designed wavelength of GaAs through plasmon-assisted electric and magnetic field concentration through a subwavelength aperture. Simulation results show up to 10-times light absorption enhancement at 867 nm due to surface plasmon polaritons (SPPs) propagation through the metal nano-grating, in comparison to conventional MSM-PD.

Call Admission Control Scheme For Improved Quality Of Service In Wimax Communication At Vehicular Speeds, Iftekhar Ahmad, Daryoush Habibi

Research outputs pre 2011

The IEEE 802.16e standard, also known as mobile WiMAX, has emerged as an exciting mobile wireless communication technology that promises to offer both high throughput and guaranteed quality of service (QoS). Call admission control (CAC) scheme serves as a useful tool for WiMAX, which ensures that resources are not overcommitted and thereby, all existing connections enjoy guaranteed QoS. Existing CAC schemes largely depend on readily available information like currently available resources and bandwidth demand of the new call while making an acceptance or rejection decision once a new request arrives. Since wireless channels are not as reliable as wired communication, …

Comparison Between Neural Network Based Pi And Pid Controllers, Mohammed Hassan, Ganesh Kothapalli

Research outputs pre 2011

The Pneumatic actuation systems are widely used in industrial automation, such as drilling, sawing, squeezing, gripping, and spraying. Also, they are used in motion control of materials and parts handling, packing machines, machine tools, and in robotics; e.g. two-legged robot. In this paper, a Neural Network based PI controller and Neural Network based PID controller are designed and simulated to increase the position accuracy in a pneumatic servo actuator. In these designs, a well-trained Neural Network provides these controllers with suitable gains depending on feedback representing changes in position error and changes in external load force. These gains should keep …

Finite Element Analysis Of A Nose Gear During Landing, Thoai D. Nguyen

UNF Graduate Theses and Dissertations

Nose gear failure is a high concern in the aviation industries. According to the Federal Aviation Administration reports, 55% of aircraft failures occur during takeoff and landing while 45% of failures occur during flight. The objective of this thesis is to determine the stress behavior and the displacement of a nose gear of an aircraft during landing using structural finite element analysis. The nose gear was first modeled using computer-aided design software and then imported into finite element software. The external forces were determined analytically and the interactions between components were carefully modeled using contact analysis. The tire was modeled …

An Investigation Of The Rwpe Prostate Derived Family Of Cell Lines Using Ftir Spectroscopy, M. Baker, Colin Clarke, D. Demoulin, J. Nicolson, Fiona Lyng, Hugh Byrne, C. Hart, M. Brown, N. Clarke, P. Gardner

Articles

Interest in developing robust, quicker and easier diagnostic tests for cancer has lead to an increased use of Fourier transform infrared (FTIR) spectroscopy to meet that need. In this study we present the use of different experimental modes of infrared spectroscopy to investigate the RWPE human prostate epithelial cell line family which are derived from the same source but differ in their mode of transformation and their mode of invasive phenotype. Importantly, analysis of the infrared spectra obtained using different experimental modes of infrared spectroscopy produce similar results. The RWPE family of cell lines can be separated into groups based …

Resonant Mie Scattering (Rmies) Correction Of Infrared Spectra From Highly Scattering Biological Samples Analyst, Paul Bassan, Achim Kohler, Harald Martens, Joe Lee, Hugh Byrne, Paul Dumas, Ehsan Gazi, Michael Brown, Noel Clarke, Peter Gardner

Articles

Infrared spectra of single biological cells often exhibit the “dispersion artefact” observed as a sharp decrease in intensity on the high wavenumber side of absorption bands, in particular the Amide I band at ~1655 cm-1, causing a downward shift of the true peak position. The presence of this effect makes any biochemical interpretation of the spectra unreliable. Recent theory has shed light on the origins of the ‘dispersion artefact’ which has been attributed to resonant Mie scattering (RMieS). In this paper a preliminary algorithm for correcting RMieS is presented and evaluated using simulated data. Results show that the ‘dispersion artefact’ …

A Comparative Study Of The Interaction Of Different Polycyclic Aromatic Hydrocarbons On Different Types Of Single Walled Carbon Nanotubes, Sourabhi Debnath, Qiaohun Cheng, Theresa Hedderman, Hugh Byrne

Articles

A comparative study of the solubilising effect of polycyclic aromatic hydrocarbon (PAHs) on single walled carbon nanotubes (SWCNTs) produced by high pressure decomposition of carbon monoxide (HiPco) and the arc discharge (AD) method has been carried out with the aid of fluorescence and Raman spectroscopy. For this study, polyphenyl and polyacene PAHs of different lengths are used. From the study it has been found that the binding energy of PAHs with AD SWCNTs is the same as that with HiPco SWCNTs. Shorter PAHs molecules better solubilise SWCNTs and in general smaller diameter SWCNTs. Thus, given their smaller diameter profile, significantly …

Ultrasound-Assisted Swnts Dispersion: Effects Of Sonication Parameters And Solvent Properties, Qiaohuan Cheng, Sourabhi Debnath, Elizabeth Gregan, Hugh Byrne

Articles

Ultrasonication is widely used for preparing Single-Walled Carbon Nanotube (SWNT) dispersions in different solvent media and it has been shown to play a critical role in dispersing and debundling SWNTs. The strong shear force that can exfoliate the SWNT bundles during sonication comes from cavitation, which entails a process of bubble formation, growth, and collapse. The efficiency of the cavitation process is closely correlated to many solvent parameters, including vapor pressure, viscosity, and surface tension, as well as the sonication frequency, intensity, and time. In this study, SWNTs were dispersed in a range of organic solvents assisted by tip sonication. …

Drug-Eluting Stents For Coronary Artery Disease: A Review, David Martin, Fergal Boyle

Articles

Over the past decade the introduction of drug-eluting stents (DESs) has revolutionised the treatment of coronary artery disease. However, in recent years concern has arisen over the long-term safety and efficacy of DESs due to the occurrence of late adverse clinical events such as stent thrombosis. With this concern in mind, research and development is currently centred on increasing the long-term safety and efficacy of DESs. The aim of this paper is to provide a thorough review of currently approved and promising investigational DESs. With dozens of companies involved in the development of new and innovative anti-restenotic agents, polymeric coatings …

Charge Injection And Clock Feedthrough, Jonathan Yu

Master's Theses

Turning off a transistor introduces an error voltage in switched-capacitor circuits. Circuits such as analog-to-digital converters (ADC), digital-to-analog converters (DAC), and CMOS image sensor pixels are limited in performance due to the effects known as charge injection and clock feedthrough. Charge injection occurs in a switched-capacitor circuit when the transistor turns off and disperses channel charge into the source and drain. The source, which is the sampling capacitor, experiences an error in the sampled voltage due to the incoming channel charge. Simultaneously, the coupling due to gate-source overlap capacitance also contributes to the total error voltage, which is known as …

A Continuous Mathematical Model Of The One-Dimensional Sedimentation Process Of Flocculated Sediment Particles, Sebastian Fernando Torrealba

University of Kentucky Doctoral Dissertations

A new continuous one-dimensional sedimentation model incorporating a new continuous flocculation model that considers aggregation and fragmentation processes was derived and tested. Additionally, a new procedure to model sediment particle size distribution (PSD) was derived. Basic to this development were three different parametric models: Jaky, Fredlund and the Gamma probability distribution (GPD) were chosen to fit three different glass micro-spheres PSDs having average particle sizes of 7, 25 and 35 microns. The GPD provided the best fit with the least parameters. The bimodal GPD was used to fit ten sediment samples with excellent results (< 5% average error). A continuous flocculation model was derived using the method of moments for solving the continuous Smoluchowski coagulation equation with fragmentation. The initial sediment PSD was modeled using a bimodal GPD. This new flocculation model resulted in a new general moments’ equation that considers aggregation and fragmentation processes, which is represented by a system of ordinary differential equations. The model was calibrated using a genetic algorithm with initial and flocculated PSDs of four sediment samples and four anionic polyacrylamides flocculants. The results show excellent correlation between predicted and observed values (R² > 0.9878). A new continuous …

Characterization Of Defects In Metal Sheets Via Infrared Thermography, Marc Anthony Harik

University of Kentucky Master's Theses

Defects in Aluminum, Stainless steel and galvanized steel sheets are studied in reflection mode infrared thermography. The effect of material properties, surface finish, heating intensity, heater emission spectra, pixel size and defect size are studied. Contrast is governed by heat quality, emissivity and defect geometry—which follows a logarithmic trend. The diameter detected via infrared thermography is found to be at least 30% larger than the measured diameter and sub-pixel defects can be detected. The use of gradient and Laplacian of temperature is introduced as a means of increasing defect contrast and mitigating heater variation.

Sustainable Resource Utilization In Manufacturing Of Printed Circuit Board Assembly: Exergy Analysis Of The Process, Subramaniam Saiganesh

University of Kentucky Master's Theses

Engineering for sustainable development requires prudent utilization of resources under economic, environmental and societal constraints. Resource utilization must follow a holistic approach. This brings in a need for comprehensive metrics which are simple, standard and universal. Thermodynamics may offer a metric that focuses on both quality and quantity of energy resources which may carry information to be combined with other metrics. This metric may be a thermodynamic property called exergy or available energy, which provides a better insight into resource use in both energy and non-energy producing systems. This thesis is devoted to a study of the exergy concept in …

Commercialization And Optimization Of The Pixel Router, Steven James Dominick

University of Kentucky Master's Theses

The Pixel Router was developed at the University of Kentucky with the intent of supporting multi-projector displays by combining the scalability of commercial software solutions with the flexibility of commercial hardware solutions. This custom hardware solution uses a Look Up Table for an arbitrary input to output pixel mapping, but suffers from high memory latencies due to random SDRAM accesses. In order for this device to achieve marketability, the image interpolation method needed improvement as well. The previous design used the nearest neighbor interpolation method, which produces poor looking results but requires the least amount of memory accesses. A cache …

Characterization Of Ni-Rich Nitihf Based High Temperature Shape Memory Alloys, Gurdish S. Ded

University of Kentucky Master's Theses

Among the potential high temperature shape memory alloys, due to its low cost, medium ductility and high work output NiTiHf seems to be the most promising HTSMA for a wide range of applications in the 100-250ºC. A detailed investigation into the shape memory properties and transformation behavior for the Ni-rich HTSMA with the compositions of Ni_45.3Cu₅Ti_29.7Hf₂₀, Ni_50.3Ti_29.7Hf₂₀ and Ni_45.3Pd₅Ti_29.7Hf₂₀ was carried out. It is possible to form Ni-rich precipitates in Ni-rich NiTiHf alloys and tailor the TTs by heat treatments …

Igf-I Releasing Plga Scaffolds For Growth Plate Regeneration, Sharath Kumar Chinnakavanam Sundararaj

University of Kentucky Master's Theses

Growth plate is a highly organized cartilaginous tissue found at the end of long bones and is responsible for longitudinal growth of the bones. Growth plate fracture leads to retarded growth and unequal limb length, which might have a lifelong effect on a person’s physical stature. This research is a tissue engineering approach for the treatment of growth plate injury. Insulin-like growth factor I (IGF-I), which can stimulate cartilage formation, was encapsulated within PLGA microspheres that were then used to form porous scaffolds. The release profile of the IGF-I from the PLGA scaffold showed a biphasic release pattern. In vitro …

Numerical Modeling Of The Dynamic Response Of A Multi-Bilinear-Spring Support System, Trey D. Gilliam

University of Kentucky Master's Theses

The Alpha Magnetic Spectrometer is an International Space Station Experiment that features a unique nonlinear support system with no previous flight heritage. The experiment consists of multiple straps with piecewise-linear stiffness curves that support a cryogenic magnet in three-dimensional space inside of a vacuum chamber. The stiffness curves for each strap are essentially bilinear and switch between two distinct slopes at a specified displacement. This highly nonlinear support system poses many questions in regards to feasible computational methods of analysis and possible response behavior. This thesis develops a numerical model for a multi-bilinear-spring support system motivated by the Alpha Magnetic …

Quality Analysis In Flexible Manufacturing Systems With Batch Productions, Junwen Wang

University of Kentucky Doctoral Dissertations

To improve product quality and reduce cost, batch production is often implemented in many exible manufacturing systems. However, the current literature does not provide any method to analyze the quality performance in a flexible manufacturing system with batch production.

In this research, we present an analytical method with closed-form formula to evaluate the quality performance in such systems. Based on the model, we discover and investigate monotonic and non-monotonic properties in quality to provide practical guidance for operation management. To improve product quality, we introduce the notions of quality improvability with respect to product sequencing. In addition, we develop the …

Near-Field Radiative Transfer: Thermal Radiation, Thermophotovoltaic Power Generation And Optical Characterization, Mathieu Francoeur

University of Kentucky Doctoral Dissertations

This dissertation focuses on near-field radiative transfer, which can be defined as the discipline concerned with energy transfer via electromagnetic waves at sub-wavelength distances. Three specific subjects related to this discipline are investigated, namely nearfield thermal radiation, nanoscale-gap thermophotovoltaic (nano-TPV) power generation and optical characterization. An algorithm for the solution of near-field thermal radiation problems in one-dimensional layered media is developed, and several tests are performed showing the accuracy, consistency and versatility of the procedure. The possibility of tuning near-field radiative heat transfer via thin films supporting surface phononpolaritons (SPhPs) in the infrared is afterwards investigated via the computation of …

Incentive Mechanisms In P2p Media Streaming Systems, Xiao Su, Suchreet Dhaliwal

Faculty Publications

This paper highlights the need to curb free-riding in P2P media streaming systems and discusses the mechanisms by which this could be accomplished. Free riding, whereby a peer utilizes network resources, but does not contribute services could have a huge impact on the efficacy of blue streaming systems, leading to scalability issues and service degradation. We discuss why BitTorrent-like tit-for-tat mechanisms cannot be simply tailored and used in streaming. Even though the problem of free riding is more severe in P2P media streaming than in file sharing, the deployed systems still lack incentive schemes. In this paper, we categorize, analyze, …

Route Change Decision Making By Hurricane Evacuees Facing Congestion, R. Michael Robinson, Asad Khattak

VMASC Publications

Successful evacuations of metropolitan areas require overcoming unexpected congestion that reduces traffic flows. Congestion may result from accidents, incidents, or other events that reduce road capacity. Traffic professionals and emergency managers may promote deviations from planned routes to bypass an area of congestion and speed mass exit. However, some route changes may actually reduce traffic flow rates, and in these cases decision makers may want to discourage use of alternate routes. By using results of a behavioral survey of potential hurricane evacuees, this study identifies variables associated with the decision to alter routes and also identifies frequently used information sources. …

Denoising Of Natural Images Using The Wavelet Transform, Manish Kumar Singh

Master's Theses

A new denoising algorithm based on the Haar wavelet transform is proposed. The methodology is based on an algorithm initially developed for image compression using the Tetrolet transform. The Tetrolet transform is an adaptive Haar wavelet transform whose support is tetrominoes, that is, shapes made by connecting four equal sized squares. The proposed algorithm improves denoising performance measured in peak signal-to-noise ratio (PSNR) by 1-2.5 dB over the Haar wavelet transform for images corrupted by additive white Gaussian noise (AWGN) assuming universal hard thresholding. The algorithm is local and works independently on each 4x4 block of the image. It performs …

Computer Forensic Functions Testing: Media Preparation, Write Protection And Verification, Yinghua Guo, Jill Slay

Journal of Digital Forensics, Security and Law

The growth in the computer forensic field has created a demand for new software (or increased functionality to existing software) and a means to verify that this software is truly forensic i.e. capable of meeting the requirements of the trier of fact. In this work, we review our previous work---a function oriented testing framework for validation and verification of computer forensic tools. This framework consists of three parts: function mapping, requirements specification and reference set development. Through function mapping, we give a scientific and systemized description of the fundamentals of computer forensic discipline, i.e. what functions are needed in the …

Table Of Contents

Journal of Digital Forensics, Security and Law

No abstract provided.

Table Of Contents

Journal of Digital Forensics, Security and Law

No abstract provided.

Clustering Spam Domains And Destination Websites: Digital Forensics With Data Mining, Chun Wei, Alan Sprague, Gary Warner, Anthony Skjellum

Journal of Digital Forensics, Security and Law

Spam related cyber crimes have become a serious threat to society. Current spam research mainly aims to detect spam more effectively. We believe the identification and disruption of the supporting infrastructure used by spammers is a more effective way of stopping spam than filtering. The termination of spam hosts will greatly reduce the profit a spammer can generate and thwart his ability to send more spam. This research proposes an algorithm for clustering spam domains extracted from spam emails based on the hosting IP addresses and tracing the IP addresses over a period of time. The results show that many …

Developing Voip Honeypots: A Preliminary Investigation Into Malfeasant Activity, Craig Valli

Journal of Digital Forensics, Security and Law

30 years ago PABX systems were compromised by hackers wanting to make long distance calls at some other entities expense. This activity faded as telephony became cheaper and PABX systems had countermeasures installed to overcome attacks. Now the world has moved onto the provision of telephony via broadband enabled Voice over Internet Protocol (VoIP) with this service now being provided as a replacement for conventional fixed wire telephony by major telecommunication providers worldwide. Due to increasing bandwidth it is possible for systems to support multiple voice connections simultaneously. The networked nature of the Internet allows for attackers of these VoIP …

Adaptation Of Pyflag To Efficient Analysis Of Seized Computer Data Storage, Aleksander Byrski, Wojciech Stryjewski, Bartłomiej Czechowicz

Journal of Digital Forensics, Security and Law

Based on existing software aimed at investigation support in the analysis of computer data storage seized during investigation (PyFlag), an extension is proposed involving the introduction of dedicated components for data identification and filtering. Hash codes for popular software contained in NIST/NSRL database are considered in order to avoid unwanted files while searching and to classify them into several categories. The extension allows for further analysis, e.g. using artificial intelligence methods. The considerations are illustrated by the overview of the system's design.