Engineering Commons^™

A Novel Microphotonic Structure For Optical Header Recognition, Muhsen Aljada, Kamal Alameh, Adam Osseiran, Khalid Al-Begain

Research outputs pre 2011

In this paper, we propose and demonstrate a new MicroPhotonic structure for optical packet header recognition based on the integration of an optical cavity, optical components and a photoreceiver array. The structure is inherently immune to optical interference thereby routing an optical header within optical cavities to different photo receiver elements to generate the autocorrelation function, and hence the recognition of the header using simple microelectronic circuits. The proof-of-concept of the proposed MicroPhotonic optical header recognition structure is analysed and experimentally demonstrated, and results show excellent agreement between measurements and theory.

Optimised Nano-Engineered 1-D Magnetophotonic Crystals For Integrated-Optical Modulators, Mikhail Vasiliev, Kamal Alameh, Vladimir Belotelov, Vyacheslav Kotov, Anotoly Zvezdin

Research outputs pre 2011

The optimization of multilayer ID megnetophotonic crystals with mulitple nano-engineered defects enables novel practical photonics applications. The properties of several optimized structures suitable for infrared intensity modulators are discussed. A novel approach to the design of integrated multi-channel WDM/DWDM transmission loss equalizers is proposed. We also show the effect of material absorption on the spectral properties of magnetic phtonic crystals, which is a factor of primary importance for the design of short-wavelenght infrared modulators.

Design Of Reconfigurable Optical Interconnects Employing Opto-Vlsi Processors, Roger Jeffery, Kamal Alameh, Mikhail Vasiliev

Research outputs pre 2011

We investigate the design and performance of a reconfigurable optical interconnect structure based on vertical-cavity surface-emitting lasers (VCSEL), Opto-VLSI processors and photodetector arrays. We optimise a proof-of-concept 3-VCSEL-element structure that eliminates crosstalk caused by unwanted diffracted optical beams and show that a bit error role (BER) of 10'17 is feasible at 3.2 Gbps for each channel.

Optimisation Of Opto-Ulsi Processor Performance Using Closed-Loop Feedback, Chung Poh, Kamal Alameh, Rong Zheng

Research outputs pre 2011

In this paper, an algorithm based on multi-variable Newton-Raphson method is developed to optimise the steering efficiency of a I-D Opto-USLI processor. The algorithm enables the evaluation of the phase-voltage relationship of the Opto-ULSI processor using realtime power measurements. The optimisation algorithm reported in the paper is crucial for reconfigurable photonic systems such as optical add drop multiplexers, optical switches, tunable optical filters and WDM equalizers.

Dynamic Opto-Vlsi Lens And Lens-Let Generation With Programmable Focal Length, Zhenglin Wang, Kamal Alameh, Rong Zheng, Salem Adherom

Research outputs pre 2011

In this paper we present and demonstrate a dynamic lens and lens array generation method with programmable focal length based on an Opto-VLSI processor. The Opto-VLSI is driven by computer generated algorithm to generate a discrete Fresnel lens phase hologram. By optimizing the phase hologram, lenses and lens arrays of different focal lengths ranging from 300mm to infinity can be realized. The optical axis of each lens element can be independently addressed to simultaneously focus and steer an optical beam within an angular range of ±0.5°.

Dynamic Wavefront Generation Technology Using Optovlsi Processor, Zhenglin Wang, Kamal Alameh, Rong Zheng

Research outputs pre 2011

In this paper we present a novel approach for dynamic wavefront generatio based on reconfigurable Opto-VLSI processing. Computer algorithms are developed to generate arbitrary quadric-phse lense and lenslet array with programmable focal lenght, beam steering and lens diameter by driving the Opto-VLSI processor with different computer generated phase holograms. Proff-of-concept experimental results show that multiple spheric and aspheric lens/lenslet wavefrongs can be generated with each lens independently addressed. The measured meaximum focal length tuning range is from +80mm to infinity and the beam scanning angular range is +7mrad, which are in excellent agreement with theory. Difference spatial profiles for wavefront …

Optical Interference Suppression Using Microphotonic Rf Filter Structure, Rong Zheng, Kamal E. Alameh, Zhenglin Wang

Research outputs pre 2011

The impact of laser coherence noise on conventional photonic RF filters is investigated in this paper. In addition, a new microphotonic adaptive RF filter structure is proposed, which can simultaneously suppress the phased-induced intensity noise caused by optical interference. Results show that the coherence length of the laser light significantly degrades the RF frequency response of a photonic transversal RF filter, whereas the microphotonic RF filter has the capability of generating arbitrary transfer function with no phase-induced intensity noise

Dynamic Spot Generation Using Opto-Vlsi Processing, Zhenglin Wang, Rong Zheng, Kamal Alameh

Research outputs pre 2011

In this paper we demonstrate the capability of OptoVLSI processors to generate arbitrary optical power distribution for adaptive optical beam splitting and dynamic optical spot generation. By using the multicasting capability of Opto-VLSI processors, an input optical signal can be dynamically split into N spots array, and the output power of each spot can be independently configured. Experimental results of multiple beam splitting show that dynamic optical multicasting can be achieved with more than 20dB dynamic range. Special patterns are also generated by optimising the phase hologram of the Opto-VLSI processor to place the output beam spots at appropriate positions.

Optical Cavity Design Of Integrated Microphotonic Wideband Adaptive Rf Signal Processor, Rong Zheng, Zhenglin Wang, Kamal Alameh

Research outputs pre 2011

In this paper. we analyse the beam propagation within the optical cavities of all integrated MicroPhotonic adaptive RF signal processor, and optimize the optical beam diameter and incidence angle that maximize the number of taps to realise high-resolution R F processor. Simulation results show that for a 1m-diameter collimated Gallssioll beam, 16 taps per cavity can be achieved for a 20mm-long cavity, and that there is no need for a diffractive optical element (DOE) to re- collimate the Gaussian beam within the cavity. The tolerance of the MicrnPhotonic processor to changes in optical cavity length which degrade the beam overlapping …

A Robust Qr Based Detector For V Blast And Its Efficient Hardware Implementation, Fariborz Sobhanmanesh, Saeid Nooshabadi, Daryoush Habibi

Research outputs pre 2011

The use of multiple antennas at both transmitting and receiving sides of a communication channel has increased the spectral efficiency to near the Shannon bound. However algorithmic complexity in the realization of the receiver is a major problem for its hardware implementation. In this paper we investigate a near optimal algorithm for V-BLAST detection in MIMO wireless communication systems based on QR factorization, offering remarkable reduction in the hardware complexity. Specifically, we analyze some hardware implementation aspects of the selected algorithm through MATLAB simulations and demonstrate its robustness. This technique can be used in an efficient fixed point VLSI implementation …

Open Source Software For Commercial Off-The-Shelf Gps Receivers, Andrew Greenberg

Dissertations and Theses

Inexpensive and commercially available Global Positioning System (GPS) receivers can be used in novel applications, such as nanosatellites and unmanned aerial vehicles (UAVs), by modifying the receiver's software. Unfortunately, typical GPS software development systems cost tens of thousands of dollars and have restrictive license agreements, such as non-disclosure agreements, for both their hardware and software. This thesis describes the design and construction of an open source GPS receiver development system that addresses these unnecessary restrictions. For the first time, any developer with a PC, a commercially available GPS receiver, and this development system can quickly and easily develop software for …

Optimizing Integrated Water Resources Management: Data, Tools, And Examples, Richard C. Peralta

Civil and Environmental Engineering Faculty Publications

Best utilizing water resources requires coordinating their availability and use in time and space. Required can be: spatially and temporally distributed data; simulators to predict system response to stimuli; procedures for defining management goals, constraints, and scenarios; optimizers to compute optimal management strategies; and appropriate strategy implementation techniques. Here, a strategy is a set of controllable groundwater extraction and injection rates and surface water diversions. Simulation/optimization (S/O) models couple simulators and optimizers to compute optimal strategies for posed management problems. S/O models are becoming more commonly used for policy, planning, system design, and management. For example, water planners and managers …

Effects Of Railroad Track Structural Components And Subgrade On Damping And Dissipation Of Train Induced Vibration, Bei Su

University of Kentucky Doctoral Dissertations

A method for numerical simulation of train induced track vibration and wave propagation in subgrade has been proposed. The method uses a mass to simulate the bogie of a train and considers the effect of rail roughness. For this method, rail roughness is considered as a randomly generated signal and a filter is used to block the undesired components. The method predicts the particle velocity around the track and can be applied to many kinds of railroad trackbeds including traditional ballast trackbed and modern Hot mix asphalt (HMA) trackbed. Results from ballast and HMA trackbeds are compared and effects of …

A Suboptimal Receiver With Turbo Block Coding For Ultra-Wideband Communications, Robert H. Morelos-Zaragoza, Timothy Becker, Sim Aquino

Faculty Publications

In this paper, the performance of adaptive equalization and turbo product coding is investigated for pulse-based UWB communications in short-range indoor environments. The sensitivity of adaptive LMS linear and nonlinear (decision-feedback) equalizers with respect to the number of training symbols and number of taps is considered. To reduce the error performance variation with respect to changing channel conditions, a turbo product code (TPC) with two component (31,26,3) Hamming codes is proposed. We report simulation results showing that channel coding not only improves error performance, but also reduces significantly the sensitivity of UWB systems in short-range indoor wireless communications.

Self-Assembly Of Ge Quantum Dots On Si(100)- 2×1 By Pulsed Laser Deposition, M. S. Hegazy, H. E. Elsayed-Ali

Electrical & Computer Engineering Faculty Publications

Self-assembled Ge quantum dots are grown on Si(100)- 2×1 by pulsed laser deposition. The growth is studied by in situ reflection high-energy electron diffraction and postdeposition atomic force microscopy. After the completion of the wetting layer, transient hut clusters, faceted by different planes, are observed. When the height of these clusters exceeded a certain value, the facets developed into {305} planes. Some of these huts become {305}-faceted pyramids as the film mean thickness was increased. With further thickness increase, dome clusters developed on the expense of these pyramids. © 2005 American Institute of Physics. [DOI: 10.1063/1.1949285]

A Study For Branch Predictors To Alleviate The Aliasing Problem, Tieling Xie, Robert Evans, Yul Chu

Electrical and Computer Engineering Faculty Publications

Modern processors usually have a deep pipeline, superscalar architecture to obtain higher performance. As pipelines are getting deeper, accurate branch prediction is critical to achieve high performance, since fetched instructions after a branch have to be flushed from inside the pipeline when the prediction is wrong. This paper studies the performance of several types of branch predictors, starting from local branch predictor and global branch predictor. Simulation results show that the global history predictor outperforms the local history predictor due to the characteristic that branches tend to be correlated. However, the global history predictor still suffers an aliasing problem that …

Indium Growth On Si(100)-2 X 1 By Femtosecond Pulsed Laser Deposition, M. A. Hafez, M. S. Hegazy, H. E. Elsayed-Ali

Electrical & Computer Engineering Faculty Publications

Indium was grown on Si (100) -2×1 at room temperature by femtosecond pulsed laser deposition. Reflection high-energy electron diffraction (RHEED) was performed in situ to study film morphology and in-plane lattice spacing. Indium was found to grow on Si (100) -2×1 by the Stranski-Krastanov mode. The initial two-dimensional In layer formed in the In-2×1 structure with a lattice constant of 3.65 Å. The full-width at half-maximum (FWHM) of the specular peak decreased during the growth, indicating an increase of the In islands size. Further In growth on the initial In-2×1 layer showed the formation of hexagonal, elongated, and hemispherical islands …

Microbubble-Based Model Analysis Of Liquid Breakdown Initiation By A Submicrosecond Pulse, J. Qian, R. P. Joshi, K. H. Schoenbach, J. Dickens, A. Neuber, M. Butcher, M. Cevallos, H. Krompholz, E. Schamiloglu, J. Gaudet

Electrical & Computer Engineering Faculty Publications

An electrical breakdown model for liquids in response to a submicrosecond(∼100ns) voltage pulse is presented, and quantitative evaluations carried out. It is proposed that breakdown is initiated by field emission at the interface of pre-existing microbubbles. Impact ionization within the microbubble gas then contributes to plasma development, with cathode injection having a delayed and secondary role. Continuous field emission at the streamer tip contributes to filament growth and propagation. This model can adequately explain almost all of the experimentally observed features, including dendritic structures and fluctuations in the prebreakdown current. Two-dimensional, time-dependent simulations have been carried out based on a …

Optimization Of Ultraviolet Emission And Chemical Species Generation From A Pulsed Dielectric Barrier Discharge At Atmospheric Pressure, Xinpei Lu, Mounir Laroussi

Electrical & Computer Engineering Faculty Publications

One of the attractive features of nonthermal atmospheric pressure plasmas is the ability to achieve enhanced gas phase chemistry without the need for elevated gas temperatures. This attractive characteristic recently led to their extensive use in applications that require low temperatures, such as material processing and biomedical applications. The agents responsible for the efficient plasma reactivity are the ultraviolet (UV) photons and the chemically reactive species. In this paper, in order to optimize the UV radiation and reactive species generation efficiency, the plasma was generated by a dielectric barrier discharge driven by unipolar submicrosecond square pulses. To keep the discharge …

Modeling And Simulation To Investigate Effects Of Static Mixer, Carrier Gas, Temperature And Pressure On The Mixing Ratio Of Carbon Nanotubes Growth Reactors, David Addie Noye

Dissertations and Theses @ UNI

The problem of this study was to investigate the effects of static mixer, carrier gas, carrier gas inlet pressures, and reactor operating temperatures on the mixing ratio of carbon nanotube synthesizing reactor. The methodology included design of static mixers, mathematical modeling, and computer modeling and simulation experiments.

The simulation experiment was performed based on single phase carrier gas modeling due to difficulty and time for three phase fluid modeling. First only nitrogen carrier gas in addition to the other three factors under constant inlet flow velocity and inlet temperature was simulated. Secondly, the same procedure was applied to argon carrier …

Mechanism Of Targeted Chemotherapeutic Delivery Using Ultrasound, Thaidra A. Gaufin, Byron K. Murray, Seiga Ohmine, Kim L. O'Neill, William G. Pitt, Briant S. Stringham

Faculty Publications

Ultrasound (US) is used to enhance and target delivery of drugs and genes to cancer tissues. The advantages of focused delivery to select tissues are manifold, but the exact mechanisms are largely unknown and need clarification to optimize delivery. The present study further defined the role of collapse cavitation in US-induced permeabilization of cell membranes and subsequent drug or gene uptake by the cell. Cavitation, defined as the collapse of micro-bubbles, produces high shear stresses and shock waves that may transiently puncture cell membranes and has been suggested as the cause of increased permeability. The hypothesis that collapsing bubbles permeabilize …

The Evidence For A Nascent Biotechnology Cluster In Cork, John W. Hobbs

Theses

Over the past 30 years, encouraged by Ireland’s low rate of corporation tax (currently 12.5 %), and active promotion of FDI by the IDA, foreign owned pharmaceutical plants have set up and multiplied in the Cork area. To Ireland’s advantages of a low tax rate, an English speaking population, a pro-business environment and membership of EU, Cork offered the added attractions of a deepwater port and large natural harbour, good freight connections, an international airport, an educated workforce and excellent sporting and leisure facilities for sailing, golf, etc. (Pfizer, Eli Lilly, Novartis, GlaxoSmithKline, Johnson & Johnson and Schering Plough have …

Automatic Generation Of Social Network Data From Electronic-Mail Communications, Jason Yee, Robert F. Mills, Gilbert L. Peterson, Summer E. Bartczack

Faculty Publications

Most organizations have formal and informal elements. Formal structures are usually documented in organizational charts showing chain of command, levels of authority, and personnel resources. The actual effectiveness of the organization or specific individuals may actually depend on informal structures and internal communication networks. These are by definition personality-dependent and may provide significant insight into how work actually gets done within the organization. Effective leaders will want insight into these informal structures for various reasons. Inefficient decision-making or staffing processes may result in unnecessary or redundant communications, chokepoints, or single points of failure, each of which can either delay decisions …

Ab Initio : A New Concept In Engineering Education, A History Of The Design, Creation And Implementation Of A New School Of Engineering In Richmond, Virginia (1990-2000), Henry A. Mcgee Jr.

VCU University History Books

Dr. Henry A. McGee, Jr., Founding Dean Emeritus of the School of Engineering at Virginia Commonwealth University, chronicles the history of the School of Engineering through his term as Founding Dean, 1994–1999. McGee details the process of creating a program aimed to balance innovation and entrepreneurship.

Joint Center Movement Analysis And 3d Motion Modeling Of Upper Arm - Comparison Of Several Algorithms With The Visual 3-D Program, Leena Joseph

Theses and Dissertations

600 out of every 100,000 people in the United States today suffer from some form of cerebellar disease that causes major abnormalities in the equilibrium and aligned, coordinated movement of the body. Hence it becomes essential to diagnose the extent of the movement and gait disorder and provide required therapy to the patients. Various developments have been made in the designing and application of interactive software system for body positioning. Object oriented design techniques are used in the field of software engineering for interactive geometric representation of system behavior. Motion analysis of the upper and lower extremities of the body …

A Study On The Nature Of Anomalous Current Conduction In Gallium Nitride, Joshua K. Spradlin

Theses and Dissertations

Current leakage in GaN thin films limits reliable device fabrication. A variety of Ga and N rich MBE GaN thin films grown by Rf, NH3, and Rf+ NH3, are examined with electrical measurements on NiIAu Schottky diodes and CAFM. Current-voltage (IV) mechanisms will identify conduction mechanisms on diodes, and CAFM measurements will investigate the microstructure of conduction in GaN thin films. With CAFM, enhanced conduction has been shown to decorate some extended defects and surface features, while CAFM spectroscopy on a MODFET structure indicates a correlation between extended defects and field conduction behavior at room temperature. A remedy for poor …

Myocardial Perfusion Imaging With Rb-82 Pet, George Nittil Francis

Theses and Dissertations

Myocardial perfusion imaging (MPI) is an effective technique used to study the left ventricular ejection function (LVEF), myocardial perfusion, wall motion, and wall thickening. Positron emission tomography (PET) and single photon emission computed tomography (SPECT) are two modalities that can be used to quantify the left global and regional perfusion at rest and stress. While PET and SPECT rely on similar principles to produce images, important differences in instrumentation and experimental applications are dictated by inherent differences in their respective physics of radioactive decay. With a sensitivity > 90% in combination with a high specificity, PET is today the best available …

Reentrainment Of Submicron Solid Particles, Ramin Mortazavi

Theses and Dissertations

In this work, an experimental method is developed to study the effects of particle size, flow rate, pulsation, particle/substrate material, and temperature on the short-term reentrainment of submicron particles. The particles tested are in the size range of 10-900 nm and are deposited by wetting the inside of capillary tubes with a liquid suspension. The tubes are then dried in a desiccator. The particles are reentrained under turbulent dry air flow conditions and a condensation particle counter is used to measure the number of entrained particles.There has been very limited work done with nanoscale particles in general and no previous …

Characterization Of Fluoropolymer Powders Made By Supercritical Assisted Mixing With Crystalline Additives, Ntoh Atem-Tambe

Theses and Dissertations

This research project investigates a new technique to efficiently mix crystalline solid additives with polymers by gentle ball milling with steel balls in the presence of carbon dioxide (C02) at 17 to 30°C and 1300 to 2500 psig. As the ball milling system is agitated, the steel balls transfer mechanical energy to the fluoropolymer and additive thereby converting them to powders. C02 is added into the chamber to expand the polymer and make it amenable to impregnation by the additive. At the end of the mixing process, a free flowing powder is produced consisting of the additive coated with fluoropolymer. …

Characterization Of Electrosprayed Poly(Vinylidene Fluoride)/Cnt Nanocomposite, Ihab Maher Abdelsayed

Theses and Dissertations

PVDF, Poly(vinylidene fluoride), is a polymer that has been studied for over four decades due to its good electromechanical properties, stability, and durability in various environments. Currently, PVDF is the only commercially available piezoelectric polymer. PVDF is a polymorph, which indicates the presence of several crystalline phases such as α, β, γ, and δ-phase. Oriented β-phase PVDF exhibits ferroelectric properties and displays the largest piezoelectricity amongst the four phases, which makes it the most desirable phase. Preparing oriented β-phase PVDF is a multi-step process, which is cost intensive, due to the time, labor and energy utilized. The main goal of …