Digital Commons Network^™

Ferritic Nitrocarburizing Process Development For Minimization Of Distortion, Chunyan Nan

Electronic Theses and Dissertations

Nitrocarburizing is a thermochemical diffusion process that has been proposed as an alternative to carbonitriding to improve the surface characteristics of automotive components without producing unacceptable part distortion. In this study, gas, ion and vacuum ferritic nitrocarburizing using various heat treatment schedules were investigated and compared with a current carbonitriding procedure. Dimensional distortion and residual stresses in Navy C-Rings and torque converter pistons resulting from each treatment process were evaluated. The microstructure and microhardness, as well as the phase composition of the specimens, were also characterized.

The results of this study indicated that the nitrocarburizing process utilizing suitable heat treatment …

Backfilling With Fairness And Slack For Parallel Job Scheduling, Wei Jin

Electronic Theses and Dissertations

Parallel jobs have different runtimes and numbers of threads/processes. Thus, scheduling parallel jobs involves a packing problem. If jobs are packed as tightly as possible, utilization will be improved. Otherwise, some resources have to stay idle. The common solution to deal with idle resources is backfilling, which schedule smaller jobs submitted later to execute earlier as long as they do not postpone the first job or all the previous jobs in the waiting queue. Traditionally, backfilling uses first fit for idle resources, according to the submission order. However, in this case, better packing of jobs could be missed. Hence, we …

Advanced Diagnostics, Control And Testing Of Diesel Low Temperature Combustion, Usman Asad

Electronic Theses and Dissertations

The conventional high temperature diesel combustion is constrained by the classical NOx-soot trade-off, so that any technique to reduce one emission generally increases the other. The simultaneous low NOx and soot can be achieved by lowering the combustion temperature and by preparing a cylinder charge of high homogeneity. However, the lowered combustion temperature may significantly reduce the fuel efficiency of such combustion cycles. Therefore, the overall objective of this work was to conduct a detailed analysis of the diesel LTC cycles that result in simultaneous low NOx and low soot, and to improve the LTC performance through advanced diagnostics and …

Optimal Channel Assignment And Power Control In Wireless Cellular Networks, Xin Yu

Electronic Theses and Dissertations

Wireless mobile communication is a fast growing field in current telecommunication industry. In a wireless cellular network, channel assignment is a mechanism that assigns channels to mobile users in order to establish a communication between a mobile terminal and a base station. It is important to determine an optimal allocation of channels that makes effective use of channels and minimizes call-blocking and call-dropping probabilities. Another important issue, the power control, is a problem of determining an optimal allocation of power levels to transmitters such that the power consumption is minimized while signal quality is maintained. In wireless mobile networks, channels …

Numerical Investigation Of Synthetic Jet Ejector (Sje) Performance, Feng Lin

Electronic Theses and Dissertations

The performance of a synthetic jet ejector (SJE) has been investigated numerically using Computational Fluid Dynamics (CFD). A parametric study was conducted and combined with a search procedure to determine the conditions for optimum volume flow rate through the device. Active parameters such as input driving frequency and input velocity amplitude as well as passive parameters describing the ejector geometry, such as the orifice diameter, shroud diameter, and shroud length were considered.

Results show that the SJE has an optimum operating condition. The optimum orifice diameter is theoretically the same as the actuator diameter, which is 0.8 times the shroud …

Study Of Challenges In Technology Development And Market Penetration Of Hybrid Electric Vehicles In Canada, Mariam Khan

Electronic Theses and Dissertations

Growing concerns of the economic and environmental impact of petroleum combustion by on-road transportation have accelerated the development of alternative fuel vehicles; of these, the hybrid electric vehicle (HEV) is currently the most commercially successful technology. It integrates an electric drivetrain to the internal combustion engine for optimized engine operation giving significantly higher fuel efficiency and lower emissions. However, despite their well recognized benefits, Canadian consumers have shown reluctance in adapting HEVs so far. This thesis discusses the immediate need for Canada to adopt more efficient and eco-friendly transportation systems and analyzes the cost effectiveness and tailpipe emissions of HEVs …

Tcp/Ip Control Server For A Multi-Drop Test Bench Network, Christopher Rennick

Electronic Theses and Dissertations

This thesis describes the design, construction and verification process in full for the test server portion of the second generation of an automated testing network. The system was built for, and with, AMD/ATI of Markham, Ontario and will be used to test large batches of their graphics processing units (GPU's). The final test system has the capability to simultaneously test and control several parameters on a large number of test nodes. The TCP/IP Control Server for a Multi-Drop Test Bench Network was designed to test and control a network of 256 test nodes over an RS-485 network. The contents of …

Integrated Placement And Routing Of Relay Nodes For Fault-Tolerant Hierarchical Sensor Networks, Yufei Xu

Electronic Theses and Dissertations

In two-tiered sensor networks, using higher-powered relay nodes as cluster heads has been shown to lead to further improvements in network performance. Placement of such relay nodes focuses on achieving specified coverage and connectivity requirements with as few relay nodes as possible. Existing placement strategies typically are unaware of energy dissipation due to routing and are not capable of optimizing the routing scheme and placement concurrently.

We, in this thesis, propose an integrated integer linear program (ILP) formulation that determines the minimum number of relay nodes, along with their locations and a suitable communication strategy such that the network has …

Extending Scojo-Pect By Migration Based On System-Level Checkpointing, Peiyu Cai

Electronic Theses and Dissertations

In recent years, a significant amount of research has been done on job scheduling in high performance computing area. Parallel jobs have different running time and require a different number of processors, thus jobs need to be scheduled and packed to improve system utilization. Scojo-PECT is a job scheduler which provides service guarantees by using coarse-grain time sharing. However, Scojo-PECT does not provide process migration. We extend the Scojo-PECT by migrating parallel jobs based on system-level checkpointing. We investigate different cases in the Scojo-PECT scheduling algorithm where migration based on system-level checkpointing can be used to improve resource utilization and …

Efficient Time Delay Estimation And Compensation Applied To The Cancellation Of Acoustic Echo, Tomi Hila

Electronic Theses and Dissertations

The system identification problem is notably dealt with using adaptive filtering approaches. In many applications the unknown system response consists of an initial sequence of zero-valued coefficients that precedes the "active" part of the response. The presence of these coefficients introduces a flat delay in the incoming signals which can take significantly large values. When most adaptive approaches attempt to model such a system, the presence of flat delay impairs their operation and performance. The approach introduced in this thesis aims to model the flat delay and "active" part of the unknown system separately. An efficient system for time delay …

Models For The Optical Dispersion Relations Of Amorphous Semiconductors, Wei Lu

Electronic Theses and Dissertations

The development of empirical expressions for the spectral dependence of the real and imaginary components of the dielectric function have proven useful over the years. These expressions can be applied in the analysis of optical data, including the interpretation of transmittance, reflectance, and ellipsometric spectra obtained from thin film semiconductors. Also, they can be used in performance simulations of optoelectronic devices, such as solar cells.

In this thesis, a critical comparison of a number of empirical models for the real and imaginary components of the dielectric function is performed. A number of crystalline and disordered semiconductors of interest are considered …

High Speed World Level Finite Field Multipliers In F2m, Ashkan Hosseinzadeh Namin

Electronic Theses and Dissertations

Finite fields have important applications in number theory, algebraic geometry, Galois theory, cryptography, and coding theory. Recently, the use of finite field arithmetic in the area of cryptography has increasingly gained importance. Elliptic curve and El-Gamal cryptosystems are two important examples of public key cryptosystems widely used today based on finite field arithmetic. Research in this area is moving toward finding new architectures to implement the arithmetic operations more efficiently.

Two types of finite fields are commonly used in practice, prime field GF(p) and the binary extension field GF(2 m). The binary extension fields are attractive …

Encoding Ultrasonic Signals To Improve The Signal To Noise Ratio For The Inline Inspection Of Spot Welds, Lawrence Barsanti

Electronic Theses and Dissertations

Inline spot weld analysis (ISWA) is a relatively new application of ultrasonic technology that is capable of assessing spot welds as they are made. In previous studies, the fundamental concepts of ISWA have been uncovered and strong correlations with other test methods have been produced. Unfortunately, the current apparatus for ISWA has a low signal to noise ratio (SNR) in some installations which can lead to unusable weld signatures and incorrect interpretations. This work applies coded ultrasonic signals to ISWA in an attempt to improve the SNR of the acquired weld signatures and Ultimately improve the reliability of ISWA.

In …

Design And Implementation Of A Real-Time Miniaturized Embedded Stereo-Vision System, Siddhant Ahuja

Electronic Theses and Dissertations

The main motivation of the thesis is to develop a fully integrated, modular, small baseline (<=3cm), low cost (<=CAD$600), real-time miniaturized embedded stereo-vision system which fits within 5x5cm and consumes very low power (700mA@3.3V). The system consists of two small profile cameras and a dualcore embedded media processor, running at 600MHz per core. The stereo-matching engine performs sub-sampling, rectification, pre-processing using census transform, correlation-based Sum of Hamming Distance matching using three levels of recursion, LRC check and post-processing. The novel post processing algorithm removes outliers due to low-texture regions and depth-discontinuities. A quantitative performance of the post processing algorithm is presented which shows that for all regions, it has an average percentage improvement of 13.61% (based on 2006 Middlebury dataset). To further enhance the performance of the system, optimization steps are employed to achieve a speed of around 10fps for disparity maps in MESVS-I and 20fps in MESVS-II system.

Low-Power Cmos Rectifier And Chien Search Design For Rfid Tags, Shu-Yi Wong

Electronic Theses and Dissertations

Automotive sensors implemented in radio frequency identification (RFID) tags can correct data errors by using BCH (Bose-Chaudhuri-Hocquenghem) decoder, for which Chien search is a computation-intensive key step. Existing low power approaches have drastically degrading performance for multiple-bit-correcting codes. This thesis presents a novel approach of using register-transfer-level (RTL) power management in the search process, leading to significant power savings for BCH codes with higher correction capability. An example for the (255, 187, 9) BCH code has been implemented in 0.18μm CMOS technology.

We also consider ways of conserving power for the sole power harvester on a passive tag – the …

Enabling Reliable And Power Efficient Real-Time Multimedia Delivery Over Wireless Sensor Networks, Tarik El-Amsy

Electronic Theses and Dissertations

There is an increasing need to run real-time multimedia applications, e.g. battle field and border surveillance, over Wireless Sensor Networks (WSNs). In WSNs, packet delivery exhibits high packet loss rate due to congestion, wireless channel high bit error rate, route failure, signal attenuation, etc... Flooding conventional packets over all sensors redundantly provides reliable delivery. However, flooding real-time multimedia packets is energy inefficient for power limited sensors and causes severe contentions affecting reliable delivery.

We propose the Flooding Zone Initialization Protocol (FZIP) to enhance reliability and reduce power consumption of real-time multimedia flooding in WSNs. FZIP is a setup protocol which …

Dynamic Analysis Of Synchronous Machine Using Neural Network Based Characterization Clustering And Pattern Recognition, Rashed Mazhar

Electronic Theses and Dissertations

Synchronous generators form the principal source of electric energy in power systems. Dynamic analysis for transient condition of a synchronous machine is done under different fault conditions. Synchronous machine models are simulated numerically based on mathematical models where saturation on main flux was ignored in one model and taken into account in another. The developed models were compared and scrutinized for transient conditions under different kind of faults – loss of field (LOF), disturbance in torque (DIT) & short circuit (SC). The simulation was done for LOF and DIT for different levels of fault and time durations, whereas, for SC …

Neudetect: A Neural Network Data Mining System For Wireless Network Intrusion Detection, Md. Zillur Rahman

Electronic Theses and Dissertations

This thesis proposes an Intrusion Detection System, NeuDetect, which applies Neural Network technique to wireless network packets captured through hardware sensors for purposes of real time detection of anomalous packets. To address the problem of high false alarm rate confronted by the current wireless intrusion detection systems, this thesis presents a method of applying the artificial neural networks technique to the wireless network intrusion detection system.

The proposed system solution approach is to find normal and anomalous patterns on preprocessed wireless packet records by comparing them with training data using Back-propagation algorithm. An anomaly score is assigned to each packet …

Using Cultural Coevolution For Learning In General Game Playing, Shiven Sharma

Electronic Theses and Dissertations

Traditionally, the construction of game playing agents relies on using pre-programmed heuristics and architectures tailored for a specific game. General Game Playing (GGP) provides a challenging alternative to this approach, with the aim being to construct players that are able to play any game, given just the rules. This thesis describes the construction of a General Game Player that is able to learn and build knowledge about the game in a multi-agent setup using cultural coevolution and reinforcement learning. We also describe how this knowledge can be used to complement UCT search, a Monte-Carlo tree search that has already been …

Extending Scojo-Pect By Migration Based On Application Level Checkpointing, Jiaying Shi

Electronic Theses and Dissertations

In parallel computing, jobs have different runtimes and required computation resources. With runtimes correlated with resources, scheduling these jobs would be a packing problem getting the utilization and total execution time varies. Sometimes, resources are idle while jobs are preempted or have resource conflict with no chance to take use of them. This greatly wastes system resource at certain degree.

Here we propose an approach which takes periodic checkpoints of running jobs with the chance to take advantage of migration to optimize our scheduler during long term scheduling. We improve our original Scojo-PECT preemptive scheduler which does not have checkpoint …

New Design Of Switched Reluctance Motor Using Finite Element Analysis For Hybrid Electric Vehicle Applications, Anas Labak

Electronic Theses and Dissertations

Switched reluctance motors (SRMs) have been gaining increasing popularity and emerging as an attractive alternative to traditional electrical motors in hybrid vehicle applications due to their simple structure, ruggedness, ability of fault-tolerance, extremely high-speed operation, high power density, and low manufacturing cost. However, large torque ripple and acoustic noise are well-known as their major disadvantages. This thesis presents a novel five-phase 15/12 SRM which features higher power density, very low level of vibration with flexibility in controlling the torque ripple profile. This design is classified as an axial field SRM, hence it needs 3-dimensional finite-element analysis model. Nonetheless, an alternative …

Aerodynamics Of Bridge-Stay Cables In The Context Of Rigid Circular Cylinder In Smooth Flow, Arash Raeesi

Electronic Theses and Dissertations

Bridge stay cables are prone to dynamic excitations by wind. Depending on the orientation and mechanical properties of cable, wind speed, and other environmental factors, unstable cable response of different features could occur. The current work focuses on exploring the possible excitation mechanisms associated with two different types of wind-induced unstable responses observed on a rigid circular cylinder model in a series of wind tunnel tests. Characteristics of critical flow past a circular cylinder model in cross-flow were first studied to provide additional insight into the impact of critical Reynolds number regime. Then, the limited-amplitude and divergent type responses of …

Mining Very Long Sequences With Plwaplong Algorithms, Kashif Saeed

Electronic Theses and Dissertations

Sequential pattern mining is the process of finding inter-transaction frequent sequential patterns from a sequential database, where records consist of ordered sets of events (or items), by applying data mining techniques on such sequential databases. Discovering sequential patterns in web server logs is an example application of sequential mining, which is useful for predicting visiting patterns of web users for such purposes as targeted advertisements. Position Coded Pre-order Linked Web Access Pattern (PLWAP) mining algorithm is one of the existing efficient web sequential pattern mining algorithms, which stores the frequently stored sequences of the entire sequential database in a compressed …

Improving The Corrosion Resistance Of A High-Strength Aluminum-Copper Casting Alloy, Madhavan Manivannan

Electronic Theses and Dissertations

The B206 alloy (up to 5 wt% Cu) is the strongest aluminum foundry alloy in current use. B206 alloy can be used in a number of automotive applications, e.g. suspension knuckles and vehicle control arms, to reduce vehicle weight. Elimination of hot tearing has reawakened the interest in the 206 alloy family. However, the B206 alloy is susceptible to intergranular/pitting corrosion which restricts its current applications.

A heterogeneous distribution of Cu-containing intermetallic precipitates in the as-cast condition resulted in severe intergranular corrosion. The improved 3-step ST + 2-step AA provides better corrosion resistance compared to 2-step ST + 1-step AA. …

Grid-Job Scheduling With Reservations And Preemption, Xiaorong Cao

Electronic Theses and Dissertations

Computational grids make it possible to exploit grid resources across multiple clusters when grid jobs are deconstructed into tasks and allocated across clusters. Grid-job tasks are often scheduled in the form of workflows which require synchronization, and advance reservation makes it easy to guarantee predictable resource provisioning for these jobs. However, advance reservation for grid jobs creates roadblocks and fragmentation which adversely affects the system utilization and response times for local jobs. We provide a solution which incorporates relaxed reservations and uses a modified version of the standard grid-scheduling algorithm, HEFT, to obtain flexibility in placing reservations for workflow grid …

G-Lomarc-Ts: Lookahead Group Matchmaking For Time/Space Sharing On Multi-Core Parallel Machines, Xijie Zeng

Electronic Theses and Dissertations

Parallel machines with multi-core nodes are becoming increasingly popular. The performances of applications running on these machines are improved gradually due to the resource competition in each node. Researches have found that coscheduling different applications with complementary resource characteristics on the same set of nodes (semi time sharing) may improve the performance. We propose a scheduling algorithm G-LOMARC-TS which incorporates both space and semi time sharing scheduling methods and matches groups of jobs if possible for coscheduling. Since matchmaking may select jobs further down the waiting queue and the jobs in front of the queue may be delayed subsequently, fairness …

Experimental Determination Of The Yield Locus Of Anisotropic Metal Sheets Using Digital Image Correlation, Neil D. Turton

Electronic Theses and Dissertations

The focus of this research was to determine the yielding and work hardening behaviour of two anisotropic steel sheets (DP600 and HSLA). Uniaxial tension and compression tests were performed in the rolling and transverse directions and at 45 degrees to the rolling direction for each sheet. Plane-strain tension tests were carried out along the rolling and transverse directions. Digital image correlation was used to determine the strain distribution throughout the gauge region.

The stress-strain response of the plane-strain tension specimen was estimated through a comparison of the experimental and numerically predicted load-strain response.

Yield stresses in uniaxial tension were obtained …

Analysis Of Scheduling In A Diagnostic Imaging Department: A Simulation Study, Brendan Eagen

Electronic Theses and Dissertations

In this thesis we present an Agent-Based Modelling Tool (ABMT) for use in the investigation of the impact that operational level changes have on diagnostic imaging scheduling and patient wait times. This tool represents a novel application of agent-based modelling in the outpatient scheduling/simulation fields. The ABMT is a decision support tool with a user friendly graphical user interface that is capable of modelling a wide array of outpatient scheduling scenarios. The tool was verified and validated using data and expertise from Hotel Dieu Grace Hospital, Windsor, Ontario, Canada. The ABMT represents a technological advancement in the modelling of multi-server, …

Adaptive Foreground Segmentation Using Fuzzy Approach, Huajing Yao

Electronic Theses and Dissertations

Intelligent visual surveillance which attempts to detect, recognize and track certain objects from image sequences is becoming an active research topic in computer vision community. Background modeling and foreground segmentation are the first two and the most important steps in any intelligent visual surveillance systems. The accuracy of these two steps highly effects performance of the following steps. In this thesis, we propose a simple and novel method which employs histogram based median method for background modeling and a fuzzy k-Means clustering approach for foreground segmentation. Experiments on a set of videos and benchmark image sequences show the effectiveness of …

Adaptive Deinterlacing Of Video Sequences Using Motion Data, Elham Shahinfard

Electronic Theses and Dissertations

In this work an efficient motion adaptive deinterlacing method with considerable improvement in picture quality is proposed. A temporal deinterlacing method has a high performance in static images while a spatial method has a better performance in dynamic parts. In the proposed deinterlacing method, a motion adaptive interpolator combines the results of a spatial method and a temporal method based on motion activity level of video sequence.

A high performance and low complexity algorithm for motion detection is introduced. This algorithm uses five consecutive interlaced video fields for motion detection. It is able to capture a wide range of motions …