Engineering Commons^™

Design Of An Integrated Starter-Alternator For A Series Hybrid Electric Vehicle: A Case Study In Axial Flux Permanent Magnet Machine Design, Jessica L. Colton

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

This thesis details the design of an electric machine to perform as both a starter and alternator in a series hybrid electric vehicle. The focus of the work is on practical design aspects specific to single-sided axial flux permanent magnet machines with non-overlapped windings. First, a characterization of the rotor losses in these machine types is presented through experimental validation of finite element analysis estimates. The approaches taken to model the axial flux geometry, especially in two-dimensions, are detailed, and the difficult issue of validating the finite element analysis estimates with experimental data is addressed with a prototype 24-slot, 20-pole …

Modeling Biological Structures Via Abstract Grammars To Solve Common Problems In Computational Biology, David J. Russell

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

Grammars are generally understood to be the set of rules that define the relationships between elements of a language. However, grammars can also be used to elucidate structural relationships within sequences constructed from any finite alphabet. In this work abstract grammars are used to model the primary and secondary structures present in biological data. These grammar models are inferred and applied to efficiently solve various sequence analysis problems in computational biology, including multiple sequence alignment, fragment assembly, database redundancy removal, and structural prediction.

The primary structures, or sequential ordering of symbols, of biological data are first modeled with Lempel-Ziv (LZ) …

Growth And Characterization Of Silicon Carbide Thin Films Using A Nontraditional Hollow Cathode Sputtering Technique, James Huguenin-Love

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

Silicon carbide (SiC) is considered a suitable candidate for high-power, high-frequency devices due to its wide bandgap, high breakdown field, and high electron mobility. It also has the unique ability to synthesize graphene on its surface by subliming Si during an annealing stage. The deposition of SiC is most often carried out using chemical vapor deposition (CVD) techniques, but little research has been explored with respect to the sputtering of SiC.

Investigations of the thin film depositions of SiC from pulse sputtering a hollow cathode SiC target are presented. Although there are many different polytypes of SiC, techniques are discussed …

Experimental Investigation Of Dielectric Barrier Impact On Breakdown Voltage Enhancement Of Copper Wire-Plane Electrode Systems, Elham Foruzan, M. Ziaee-Nezhad, A. A. Shayegani-Akmal, K. Niayesh

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

Non-pressurized air is extensively used as basic insulation media in medium / high voltage equipments. An inherent property of air-insulated designs is that the systems tend to become physically large. Application of Dielectric barrier can increase the breakdown voltage and therefore decrease the size of the equipments.

In this paper, the impact of dielectric barrier on breakdown voltage enhancement of a copper wire-plane system is investigated. For this purpose, the copper wire is covered with different dielectric materials. Depending on the air gap and dielectric strength of the barrier the breakdown can be initiated in the solid or gas dielectric. …

A New Perspective On First Read Rate Of 2d Barcodes In Mobile Applications, Keng Tiong (Alf) Tan, Douglas Chai

Research outputs pre 2011

The first read rate (FRR) has been one of the traditional benchmark metric for measuring the performance of barcode systems. In recent studies, it has been noted that the FRR alone is not a complete measure of user experience, especially of barcodes in mobile applications. In this paper, we present a further three factors that would influence the user experience of mobile 2D barcodes. Our investigation is based on a quantitative survey of a controlled study participated by 250 lay users of mobile phones, through reading QRCode and Data Matrix barcodes with a variety of camera mobile phones. Observations from …

Bandwidth Allocation And Routing Information For Wireless Mobile Ad-Hoc Networks, Rajeshkumar Ramraj

Research outputs pre 2011

An admission control Algorithm must organize among flows and should afford assurance of how the medium is shared between nodes. In a wired network, nodes can keep an eye on the medium to see how much bandwidth is being used by the network. On the other hand, in an Ad-Hoc network, during communication nodes possibly will use the bandwidth of neighbouring nodes. Consequently, the bandwidth consumption of flows and the accessible resources to a node are not local concepts, other than it being linked to the neighbouring nodes in carrier-sensing range. Current solutions do not address how to perform admission …

Photovoltaic Micro-Cell Design For Distrubuted Power In Sensor Networks, Gary A. Allwood, Graham Wild, Steven Hinckley

Research outputs pre 2011

We present a new study of power over optical fiber, for use in optical fiber smart sensor networks, using silicon-based photovoltaic micro-cells. A number of parameters in the design of the micro-cell for implementation in a power converter chip have been investigated. Matching the beam profile to the active region, as well as maximizing the contact area improves the device efficiency. The effect of doping profile and junction type on the device performance, suggests silicon is a cost effective and suitable material for this application.

The Properties Of Nanocomposite (Bidy)3(Fega)5o12:Bi2o3 Magneto-Optic Garnet Films For Applications In Nanophotonics, Ultrafast Switching And Integrated Optoelectronics, Mikhail Vasiliev, Mohammad Nur E Alam, Viacheslav Kotov, Kamal Alameh

Research outputs pre 2011

We investigate the properties and applications of newly-developed RF-sputtered nano-composites with record-high magneto-optic quality (exceeding 25° at 532 nm and 42° at 635 nm). Bi-substituted dysprosium-gallium iron garnet layers with excess co-sputtered bismuth oxide content are demonstrated to possess very attractive optical and magnetic properties, which makes them suitable for novel magneto-optic and nanophotonic applications.

Opto-Vlsi-Based Rf Beamformer For Space Division Multiple Access Network, Budi Juswardy, Feng Xiao, Kamal Alameh

Research outputs pre 2011

In this paper, the architecture of a photonic-assisted smart antenna for Space-division Multiple Access (SDMA) is described. Antenna beam steering is achieved by generating independent true-time delay (TTD) for each element in the antenna arrays, through the use of an Opto-VLSI Processor in conjunction with a 10-km single mode optical fibre. Experimental results demonstrate RF beam steering in 4-element linear patch antenna array operating at 1.85GHz are presented.

Multi-Wavelength Laser Scanning Architecture For Object Discrimination, Kavitha Venkataraayan, Sreten Askraba, Kamal Alameh, Clifton Smith

Research outputs pre 2011

A novel method for identifying and discriminating various objects using five different lasers is described. This method uses a laser combination module that allows five laser diodes of different wavelengths to sequentially emit identically polarized light beams through a common aperture, along one optical path. Each laser beam enters a custom-made curved optical cavity for multi-beam spot generation through internal partial beam reflection. The intensity of the reflected light beams from each spot is detected by a high-speed area scan image sensor. Object discrimination based on analyzing the Gaussian profile of reflected laser light at distinguishing wavelengths is demonstrated.

Opto-Vlsi-Based Tunable Linear-Cavity Fibre Laser, David Michel, Feng Xiao, Kamal Alameh

Research outputs pre 2011

A novel approach using an Opto-VLSI processor to achieve a tunable fibre laser is presented. The Opto-VLSI based fibre laser is able to tune wavelengths and maintain a high Side-Mode Suppression Ratio (SMSR) even when the output optical power is low. Experimental results show a continuously tunable fibre laser source with a tuning range as high as 30 nm and a SMSR exceeding 30 dB.

High Utility Video Surveillance System On Public Transport Using Wimax Technology, Iftekhar Ahmad, Daryoush Habibi

Research outputs pre 2011

Video surveillance on public transport is a useful tool to fight against anti-social behaviour like vandalism, harassment, graffiti and terrorism. Real-time video surveillance on moving public transport faces serious technological challenges mainly due to limited throughput offered by existing communication technologies at high vehicular speeds. Success of real-time video surveillance on public transport heavily depends on future communication technologies like WiMAX. WiMAX has emerged as an exciting technology with promises to offer high throughput and improved quality of services (QoS), key requirements for video surveillance on public transport. WiMAX however, offers limited throughput at high vehicular speeds mainly because of …

Call Admission Control Scheme For The Ieee 802.16e At Vehicular Speeds, Iftekhar Ahmad, Daryoush Habibi

Research outputs pre 2011

The IEEE 802.16e standard has emerged as an exciting mobile wireless broadband technology that promises to deliver both high throughput and guaranteed quality of service (QoS). Call admission control (CAC) scheme serves as a great utility for WiMAX, which ensures that resources are not over committed and thereby, all existing connections enjoy guaranteed quality of service. Existing CAC schemes largely depend on computation of available resources while making an acceptance or rejection decision once a new request arrives. Since wireless channels are not as reliable as wired communication, CAC scheme in WiMAX communication faces a serious challenge of making a …

Simulation Of A Hybrid Polywell And Stacked Gradient Poly-Homojunction Cmos Photodiode, Paul V. Jansz, Steven Hinckley

Research outputs pre 2011

In this paper, we have simulated the performance of a photodiode array that has multiple wells per pixel as well as a stacked-gradient poly-homojunction (StaG) geometry. The pixel response resolution was improved when the first StaG epilayer was within 2 μm of the space charge region (SCR).

Jpeg Compression Of Monochrome 2d-Barcode Images Using Dct Coefficient Distributions, Keng Teong Tan, Douglas Chai

Research outputs pre 2011

Two dimensional (2D) barcodes are becoming a pervasive interface for mobile devices, such as camera phones. Often, only monochrome 2D-barcodes are used due to their robustness in an uncontrolled operating environment of camera phones. Most camera phones capture and store such 2D-barcode images in the baseline JPEG format. As a lossy compression technique, JPEG does introduce a fair amount of error in the decoding of captured 2D-barcode images. In this paper, we introduce an improved JPEG compression scheme for such barcode images. By altering the JPEG compression parameters based on the DCT coefficient distribution of such barcode images, the improved …

Adiabatic Coherent Quantum Tunneling Of Ultracold Atoms Trapped In An Asymmetrical Two-Dimensional Magnetic Lattices, Ahmed Abdelrahman, Kamal Alameh, Peter Hannford

Research outputs pre 2011

We propose a new method to realize a two-dimensional magnetic lattice, having two different configurations of asymmetric magnetic lattice, which exhibits magnetic band gap structure, and a symmetric magnetic lattice. We also describe the tunneling mechanisms of magnetically trapped ultracold atoms, prepared in a degenerate quantum gas such as Bose-Einstein Condensate (BEC). A coherent quantum tunneling of ultracold atoms between the sites of the asymmetrical magnetic lattice can be realized which induces the adiabatically controlled dc Josephson current. At critical phase transitions, namely at certain values of site phase difference and population fraction, a plasma oscillation can be observed in …

Pspice Simulation Of An Electro-Acoustic Communications Channel, Graham Wild, Steven Hinckley

Research outputs pre 2011

In this paper, we present results from a circuit simulation of a proposed electro-acoustic communications channel. The communications channel was modeled in PSpice using Redwood's version of Mason's equivalent circuit. The simulations used binary phase shift keyed communications signals with a carrier frequency of 1.12 MHz. Results obtained from the model are comparable with the results obtained experimentally. The frequency response of the model matched the measured frequency response, predicting lower frequency resonances obtained in the experimental data. The transient response of the model compares almost identically with the transient response observed experimentally. This is a significant characteristic as the …

The Use Of Alignment Cells In Mmcc Barcode, Siong Khai Ong, Douglas Chai, Alexander Rassau

Research outputs pre 2011

The QR code, a monochrome 2D barcode, is a popular and commonly used barcode system worldwide. QR codes can easily be read using a mobile phone with the appropriate decoder. As there is an increasing need for higher data capacity barcodes, some newer 2D barcodes, such as the MMCC code, have adopted the use of colour. However, the use of colour introduces more challenges for mobile phone decoders than with monochrome codes. In this paper, the use of alignment cells within the MMCC code is proposed to improve the robustness of the colour barcode when used in a mobile environment. …

Wireless Acoustic Communications And Power Supply For In-Vivo Biomedical Devices, Graham Wild, Steven Hinckley

Research outputs pre 2011

Pacemakers are common biomedical devices used in the treatment of specific cardiovascular problems. Current research in biomedical engineering is investigating the use of so called brain pacemakers to regulate conditions such as Parkinson's and other neurological conditions. In this paper, we demonstrate the principle of acoustic communications and power harvesting, in vivo. The signals are intended to be used for fixed in vivo biomedical devices, such as pacemakers, were wired and wireless RF communications cannot be used. Results show the performance of the communications channel. The frequency response, transfer function and transient response (at resonance) of the communications channel were …

Effect Of A Polywell Geometry On A Cmos Photodiode Array, Paul V. Jansz, Steven Hinckley, Graham Wild

Research outputs pre 2011

The effect of a polywell geometry hybridized with a stacked gradient poly-homojunction architecture, on the response of a CMOs compatible photodiode array was simulated. Crosstalk and sensitivity improved compared to the polywell geometry alone, for both back and front illumination

Spatial Performance Of Acousto-Ultrasonic Fiber Bragg Grating Sensor, Graham Wild, Steven Hinckley

Research outputs pre 2011

In this letter, we present results for the spatial performance of a fiber Bragg grating (FBG) sensor to continuous-wave acousto-ultrasonic (AU) signals. The FBG AU sensor is an intensity sensor, using a transmit reflect detection system. The AU sensor was used to receive actively generated continuous-wave ultrasonic signals from a PZT transducer. We present results showing the received signal strength as a function of longitudinal, lateral, and angular separation in small aluminum panels. Measurements were taken for distances of less then 100 mm and at angles from 0 to 90 degrees between the sensor and the transducer. These results show …

Adaptive Optical Splitter Employing An Opto-Vlsi Processor And A 4-F Imaging System, Haithem Ab Mustafa, Feng Xiao, Kamal Alameh

Research outputs pre 2011

A novel adaptive optical splitter structure employing an Opto-VLSI processor and 4-f imaging system is proposed and experimentally demonstrated. By driving the Opto-VLSI processor with computer generated multicasting phase holograms, an input optical signal launched into an input optical fiber port can be split and coupled into many output optical fiber ports with arbitrary splitting ratios. A proof-of-principle 1 2 adaptive optical splitter structure driven by optimized multicasting phase holograms uploaded onto the Opto-VLSI processor is developed, demonstrating an arbitrary splitting ratio over a wavelength range exceeding 50 nm.

Adaptive Multi/Demultiplexers For Optical Signals With Arbitrary Wavelength Spacing, Feng Xiao, Kamal Alameh

Research outputs pre 2011

We propose and demonstrate the principle of a novel adaptive wavelength division multiplexer/demultiplexer structure based on Opto-VLSI processing. By driving an Opto-VLSI processor with an appropriate phase hologram, optical signals of arbitrary wavelengths from different input fiber ports can be multiplexed into a common output fiber port. In addition, wavelength division multiplexed channels of arbitrary wavelength spacings can also be demultiplexed and dynamically routed into arbitrary output fiber ports. A proof-of-principle 1×3 adaptive multiplexer/demultiplexers is experimentally demonstrated.

Cladding Modes Analysis Of Photonics Crystal Fiber For Refractive Index Sensors Using Finite Element Method, Naeem Khurram, Linh Viet Nguyen, Kamal Alameh, Youngjoo Chung

Research outputs pre 2011

We developed a Finite Element package to analyze cladding mode field extensions into the air-holes of photonics crystal fiber for refractive index sensing. Our analysis could determine the most sensitive cladding mode for liquid sensing.

Technological Challenges Of 1-Dimensional Magnetic Photonic Crystals, Mikhail Vasiliev, Kamal Alameh, Dmitry E. Balabanov, Vladimir I. Burkov, V. V. Koledov, Viacheslav A. Kotov, V. G. Shavrov, Anotoly K. Zvezdin

Research outputs pre 2011

Visible-region magnetic photonic crystals (MPC) designed for higher-order bandgap operation have been proposed to overcome the technological restrictions originating from the strong thickness dependency of the individual magnetic layer properties observed in MPC structures.

Experimental Investigation Of Magnetic Circular Dichroism Spectrum And Stress Induced Optical Activity In A Single-Defect Photonic Crystal, Mikhail Vasiliev, Kamal Alameh, Vladimir I. Burkov, V. V. Koledov, Viacheslav A. Kotov, V. G. Shavrov, Anotoly K. Zvezdin

Research outputs pre 2011

Experimental investigation results for the magnetic circular dichroism spectrum (MCD) of a photonic crystal (PC) are presented. We found that in the vicinity of the transmission peak within the photonic bandgap and also near the bandgap edges, the circular dichroism is measurable even in the absence of any applied magnetic field. The application of magnetic field leads to generating an additional MCD signal measurable at the wavelengths near the “defect mode” transmittance line.

Challenges And Opportunities For Simulation Modelling Integrating Mine Haulage And Truck Shop Operations, Melinda Hodkiewicz, Steven Richardson, Richard Durham

Research outputs pre 2011

Historically considerable work has been done to develop models that simulate truck haulage for both underground and open-pit operations. However, this work frequently simplifies or overlooks aspects such as the reliability of the trucks, priority setting and maintenance strategies in the truck shop, and resourcing of the repair facilities. This paper provides an overview of work in this area that is specific to the mining industry and also relevant work from other sectors that might inform how improvements can be made. The paper proposes some specific projects that will assist in identifying technical issues. Initially, it is important to understand …

Design Of Functionally Graded Carbon Coatings Against Contact Damage, Rajnish K. Singh, Zhifeng Zhou, Lawrence Kwok Yan Li, Paul Munroe, Mark Hoffman, Zonghan Xie

Research outputs pre 2011

Three different functionally graded amorphous carbon (a-C) thin films were deposited on to aluminium substrates using a closed-field unbalanced magnetron sputtering ion plating method. The closed-field configuration prohibits the loss of secondary electrons and consequently enhances the plasma density significantly. The functional gradient of the a-C films was achieved by varying the bias voltage linearly during deposition. Three graded a-C systems possessing different variations in Young's modulus were deposited with the highest Young's modulus at the (i) top surface, (ii) interface or (iii) middle of the film. Of the three systems investigated, the one with the highest Young's modulus at …

Groove Shape-Dependent Absorption Enhancement Of 850 Nm Msm Photodetectors With Nano-Gratings, Narottam Das, Ayman Karar, Mikhail Vasiliev, Chee Leong Tan, Kamal Alameh, Yong Tak Lee

Research outputs pre 2011

Finite difference time-domain (FDTD) analysis is used to investigate the light absorption enhancement factor dependence on the groove shape of the nano-gratings etched into the surfaces of metal-semiconductor-metal photodetector (MSM-PD) structures. By patterning the MSM-PDs with optimized nano-gratings a significant improvement in light absorption near the design wavelength is achieved through plasmon-assisted electric field concentration effects. Simulation results show about 50 times light absorption enhancement for 850 nm light due to improved optical signal propagation through the nano-gratings.

Absorption Enhancement Of Msm Photodetector Structure With A Plasmonic Double Grating Structure, Chee Leong Tan, Volodymyr V. Lysak, Narottam Das, Ayman Karar, Kamal Alameh, Yong Lee

Research outputs pre 2011

We present finite difference time domain simulation to analyze the optical absorption enhancement of metal-semiconductor-metal photo detectors employing double plasmonic grating structures. Simulation results show that the combination of a subwavelength aperture and double nano-structured metal grating results in up to 25 times enhancement in optical absorption, in comparison to MSM photodetector structures employing only a subwavelength aperture. This improvement of the absorption enhancement is due to the coupling out function of the bottom grating structure which distributes the light to both side of the subwavelength aperture.