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Now showing items 1-10 of 32

#### An Ontology-Based Approach To Concern-Specific Dynamic Software Structure Monitoring

(University of Waterloo, 2006)

Software reliability has not kept pace with computing hardware. Despite the use reliability improvement techniques and methods, faults remain that lead to software errors and failures. Runtime monitoring can improve software reliability by detecting certain errors before failures occur. Monitoring is also useful for online and electronic services, where resource management directly impacts reliability and quality. For example, resource ownership errors can accumulate over time (e. g. , as resource leaks) and result in software aging. Early detection of errors allows more time for corrective action before failures or service outages occur. In addition, the ability to monitor individual software concerns, such as application resource ownership structure, can help support autonomic computing for self-healing, self-adapting and self-optimizing software. <br /><br /> This thesis introduces

**ResOwn**- an application resource ownership ontology for interactive session-oriented services. ResOwn provides software monitoring with enriched concepts of application resource ownership borrowed from real-world legal and ownership ontologies. ResOwn is formally defined in OWL-DL (Web Ontology Language Description Logic), verified using an off-the-shelf reasoner, and tested using the call processing software for a small**private branch exchange (PBX)**. The ResOwn Prime Directive states that every object in an operational software system is a resource, an owner, or both simultaneously. Resources produce benefits. Beneficiary owners may receive resource benefits. Nonbeneficiary owners may only manage resources. This approach distinguishes resource ownership use from management and supports the ability to detect when a resource's role-based runtime capacity has been exceeded. <br /><br /> This thesis also presents a greybox approach to concern-specific, dynamic software structure monitoring including a monitor architecture, greybox interpreter, and algorithms for deriving monitoring model from a monitored target's formal specifications. The target's requirements and design are assumed to be specified in SDL, a formalism based on communicating extended finite state machines. Greybox abstraction, applicable to both behavior and structure, provides direction on what parts, and how much of the target to instrument, and what types of resource errors to detect. <br /><br /> The approach was manually evaluated using a number of resource allocation and ownership scenarios. These scenarios were obtained by collecting actual call traces from an instrumented PBX. The results of an analytical evaluation of ResOwn and the monitoring approach are presented in a discussion of key advantages and known limitations. Conclusions and recommended future work are discussed at the end of the thesis....#### Design and Development of a Power Modulator for Insulation Testing

(University of Waterloo, 2006)

Variable speed drives allow for more precise speed control of induction motors, are of high power factor, and offer fast response characteristics, compared to older technologies, such as motor-generator sets and eddy current ...

#### Issues in Implementation of Public Key Cryptosystems

(University of Waterloo, 2006)

A new class of moduli called the low-weight polynomial form integers (LWPFIs) is introduced. LWPFIs are expressed in a low-weight, monic polynomial form,

**p**=**f**(**t**). While the generalized Mersenne numbers (GMNs) proposed by Solinas allow only powers of two for**t**, LWPFIs allow any positive integers. In our first proposal of LWPFIs, we limit the coefficients of**f**(**t**) to be 0 and ±1, but later we extend LWPFIs to allow any integer of less than**t**for the coefficients of**f**(**t**). Modular multiplication using LWPFIs is performed in two phases: 1) polynomial multiplication in Z[**t**]/**f**(**t**) and 2) coefficient reduction. We present an efficient coefficient reduction algorithm based on a division algorithm derived from the Barrett reduction algorithm. We also show a coefficient reduction algorithm based on the Montgomery reduction algorithm. We give analysis and experimental results on modular multiplication using LWPFIs. <br /><br /> New three, four and five-way squaring formulae based on the Toom-Cook multiplication algorithm are presented. All previously known squaring algorithms are symmetric in the sense that the point-wise multiplication step involves only squarings. However, our squaring algorithms are asymmetric and use at least one multiplication in the point-wise multiplication step. Since squaring can be performed faster than multiplication, our asymmetric squaring algorithms are not expected to be faster than other symmetric squaring algorithms for large operand sizes. However, our algorithms have much less overhead and do not require any nontrivial divisions. Hence, for moderately small and medium size operands, our algorithms can potentially be faster than other squaring algorithms. Experimental results confirm that one of our three-way squaring algorithms outperforms the squaring function in GNU multiprecision library (GMP) v4. 2. 1 for certain range of input size. Moreover, for degree-two squaring in Z[**x**], our algorithms are much faster than any other squaring algorithms for small operands. <br /><br /> We present a side channel attack on XTR cryptosystems. We analyze the statistical behavior of simultaneous XTR double exponentiation algorithm and determine what information to gather to reconstruct the two input exponents. Our analysis and experimental results show that it takes**U**<sup>1. 25</sup> tries, where**U**= max(**a**,**b**) on average to find the correct exponent pair (**a**,**b**). Using this result, we conclude that an adversary is expected to make**U**<sup>0. 625</sup> tries on average until he/she finds the correct secret key used in XTR single exponentiation algorithm, which is based on the simultaneous XTR double exponentiation algorithm....#### Channel Estimation and Equalization for Cooperative Communication

(University of Waterloo, 2006)

The revolutionary concept of space-time coding introduced in the last decade has demonstrated that the deployment of multiple antennas at the transmitter allows for simultaneous increase in throughput and reliability because ...

#### Design of a MOSFET-Based Pulsed Power Supply for Electroporation

(University of Waterloo, 2006)

The use of high-voltage pulsed electric fields in biotechnology and medicine has lead to new methods of cancer treatment, gene therapy, drug delivery, and non-thermal inactivation of microorganisms. Regardless of the application, the objective is to open pores in the cell membrane and hence either facilitate the delivery of foreign materials inside the cell or to kill the cell completely. Pulsed power supplies are needed for electroporation, which is the process of applying pulsed electric fields to biological cells to induce a temporary permeability in the cell membrane. The applications of pulsed electric fields are dependent on the output pulse shape and pulse parameters, both of which can be affected by the circuit parameters of the pulsed power supply and the conductivity of the media being treated. <br /><br /> In this research, two Metal Oxide Field Effect Transistor (MOSFET)-based pulsed power supplies that are used for electroporation experiments were designed and built. The first used up to three MOSFETs in parallel to deliver high voltage pulses to highly conductive loads. To produce pulses with higher voltages, a second pulsed power supply using two MOSFETs connected in series was designed and built. The parallel and series MOSFET-based pulsed power supplies are capable of producing controllable square pulses with widths of a few hundred nanoseconds to dc and amplitudes up to 1500 V and 3000 V, respectively. The load in this study is a 1-mm electroporation cuvette filled with a buffer solution that is varied in conductivity from 0. 7 mS/m to 1000 mS/m. The results indicate that by controlling the circuit parameters such as the number of parallel MOSFETs, gate resistance, energy storage capacitance, and the parameters of the MOSFET driver gating pulses, the output pulse parameters can be made almost independent of the load conductivity. <br /><br /> Using the pulsed power supplies designed in this work, an investigation into electroporation-mediated delivery of a plasmid DNA molecule into the pathogenic bacterium

**E. coli**O157:H7, was conducted. It was concluded that increasing the electric field strength and pulse amplitude resulted in an increase in the number of transformants. However, increasing the number of pulses had the effect of reducing the number of transformants. In all of the experiments the number of cells that were inactivated by the exposure to the pulsed electric field was measured....#### On-line Monitoring and Oscillatory Stability Margin Prediction in Power Systems Based on System Identification

(University of Waterloo, 2006)

Poorly damped electromechanical modes detection in a power system and corresponding stability margins prediction are very important in power system planning and operation, and can provide significant help to power system ...

#### Application of Non-linear Optimization Techniques in Wireless Telecommunication Systems

(University of Waterloo, 2006)

Non-linear programming has been extensively used in wireless telecommunication systems design. An important criterion in optimization is the minimization of mean square error. This thesis examines two applications: ...

#### Voltage Sag Ride-Through and Harmonics Mitigation for Adjustable Speed Drives using Dual-Functional Hardware

(University of Waterloo, 2006)

Great portion of today's industry are

**Adjustable Speed Drives**(**ASD's**) operated in order to fulfill certain processes. When these processes are critical ones or sensitive to voltage disturbances, that might take place due to inserting high load in an area near to the Point of Common Coupling (**PCC**) of the process or due to a short term outage, few tens of thousands up to millions of dollars will be lost once such interruptions (voltage sags) take place as a result of the process failure. On the other hand, a distorted voltage waveform at the PCC for some sensitive process might malfunction as a result of the high harmonic content of the voltage waveform. Utilities are required to deliver as pure as possible sinusoidal voltage waveform according to certain limits; thus, they might apply fines against the consumers who are responsible for producing high amounts of current harmonics that affect the voltage wave shape at the**PCC**in order to force them to improve the consumer's load profile by adding filters at**PCC**for instance. Utilities are charging the consumers who are drawing power at poor power factor as well. <br /><br /> This thesis presents an**ASD**retrofitted with a dual-functional piece of hardware connected in series to its**DC-link**that is capable of handling the previously two mentioned problems. In other words, hardware that is capable of providing**voltage sag ride-through**during the voltage sag conditions on one side, on the other side, during the normal operating conditions, it is capable to mitigate the harmonic contents of the drawn current by the ASD's rectifier and to improve the power factor. <br /><br /> Survey on voltage sag ride-through for ASD's approaches are presented in the literature has been made. Approaches are classified as the topology utilized; first, topologies that utilizes energy storage elements that store energy to compensate the DC-link voltage with during the voltage sags, second, topologies retrofitting the DC-link itself with additional hardware to compensate the DC-link voltage. The first group is capable to provide voltage compensating during the full outages while the second can't. The presented voltage sag ride-through work of this thesis belongs to the second group. <br /><br /> Boost converter has been used as the hardware to compensate the DC-link voltage because of its simplicity and cheap price. An adaptive linear network (ADALINE) is investigated as the detection system to detect the envelope of the input voltage waveform. Once the envelope of the voltage goes below a certain level, the boost converter is activated to compensate the difference between voltage set point and the actual DC-link voltage. Simulation results supporting the proposed configuration are presented. <br /><br /> A third-harmonic current injection approach is utilized in this work in order to achieve**total harmonic distortion**(**THD**) mitigation from 32% to 5. 125% (theoretically). Two third-harmonic current injection networks have been investigated; one utilizes a real resistor, the other utilizes a resistor emulator to reduce the energy dissipated. The proposed controller for the resistor emulator does not require a proportional-integral (PI) controller. <br /><br /> As a result of the common devices between the voltage sag ride-through circuitry and the harmonic mitigation one, they can be integrated together in one circuitry connected in series with the DC-link of the ASD. And hence, the dual functionality of the hardware will be achieved. Simulation results supporting the theoretical results have been presented....#### Practical Routing in Delay-Tolerant Networks

(University of Waterloo, 2006)

Delay-tolerant networks (DTNs) have the potential to connect devices and areas of the world that are under-served by traditional networks. The idea is that an end-to-end connection may never be present. To make ...

#### Multi-Port RF MEMS Switches and Switch Matrices

(University of Waterloo, 2006)

Microwave and millimeter wave switch matrices are essential components in telecommunication systems. These matrices enhance satellite capacity by providing full and flexible interconnectivity between the received and ...