Dissertations and Theses

A review of the literature regarding risk management and effective risk communications identified that very few researchers have addressed risk assessment confidence levels when using risk scoring methods. The focus of this research is to develop a definition of risk assessment confidence levels for use in internal project management communications and to evaluate its usefulness. This research ...

Future microprocessors pose many challenges to the power conversion techniques. Multiphase synchronous buck converters have been widely used in high current low voltage microprocessor application. Design optimization needs to be carefully carried out with pushing the envelope specification and ever increasing concentration towards power saving features. In this work, attention has been focused ...

Passive components are indispensable in the design and development of microchips for high-frequency applications. Inductors in particular are used frequently in radio frequency (RF) IC's such as low-noise amplifiers and oscillators. High performance inductor has become one of the critical components for voltage controlled oscillator (VCO) design, for its quality factor (Q) value directly affect...

In this dissertation, the response time issue of the liquid crystal (LC) devices is investigated in meeting the challenges for display and photonic applications. The correlation between the LC director response time and the optical response time is derived theoretically and confirmed experimentally. A major contribution of this thesis is that, based on the small angle approximation, we derive r...

Since it's release in Dec 2000, there has been a slow movement towards the new version of ISO 9001:2000 by ISO 9000:1994 certified organizations. Of the 561,747 ISO 9000 certified businesses, 167,210 are certified under the new ISO 9001:2000, which is less than 30 % of the total ISO 9000 certified companies. Although many studies have been conducted to understand and assess the practices of ISO...

The development in power conversion technology is in constant demand of high power efficiency and high power density. The DC-DC power conversion is an indispensable stage for numerous power supplies and energy related applications. Particularly, in PV micro-inverters and front-end converter of power supplies, great challenges are imposed on the power performances of the DC-DC converter stage, w...

This dissertation consists of four papers concerning impacts of zinc orthophosphate (ZOP) inhibitor on iron, copper and lead release in a changing water quality environment. The mechanism of zinc orthophosphate corrosion inhibition in drinking water municipal and home distribution systems and the role of zinc were investigated. Fourteen pilot distribution systems (PDSs) which were identical and...

In this dissertation, the research mainly focused on discussing ESD failure event simulation and ESD modeling, seeking solutions for ESD issues by simulating ESD event and predict possible ESD reliability problem in IC design. The research involves failure phenomenon caused by ESD/ EOS stress, mainly on the thermal failure due to inevitable self-heating during an ESD stress. Standard Complement...

Medical simulation has facilitated the understanding of complex biological phenomenon through its inherent explanatory power. It is a critical component for planning clinical interventions and analyzing its effect on a human subject. The success of medical simulation is evidenced by the fact that over one third of all medical schools in the United States augment their teaching curricula using p...

Power management solutions such as voltage regulator (VR) mandate DC-DC converters with high power density, high switching frequency and high efficiency to meet the needs of future computers and telecom equipment. The trend towards DC-DC converters with higher switching frequency presents significant challenges to power MOSFET technology. Optimization of the MOSFETs plays an important role in i...

Evolutions in integrated circuit technology require the use of a high-frequency synchronous buck converter in order to achieve low cost, low profile, fast transient response and high power density. However, high frequency operation leads to increased power MOSFET switching losses. Optimization of the MOSFETs plays an important role in improving converter performance. This dissertation focuses o...

One of the major concerns in the behavior of an earth dam is the change in the exit gradient and the impact on the slope stability under drawdown conditions. Drawdown can cause increased seepage forces on the upstream slope which may result in the movement of soil particles in the flow direction and cause erosion problems. In this research, a numerical approach, based on the finite element meth...

The dissertation is concerned with the design of high-efficiency permanent magnet synchronous machinery and the control system. The dissertation first talks about the basic concept of the permanent magnet synchronous motor (PMSM) design and the mathematics design model of the advanced design method. The advantage of the design method is that it can increase the high load capacity at no cost of ...

Nowadays, big data systems (e.g., Hadoop and Spark) are being widely adopted by many domains for offering effective data solutions, such as manufacturing, healthcare, education, and media. A common problem about big data systems is called anomaly, e.g., a status deviated from normal execution, which decreases the performance of computation or kills running programs. It is becoming a necessity t...

The extensive use of Integrated Circuits (ICs) means complex working conditions for these tiny chips. To guarantee the ICs could work properly in various environments, some special protection strategies are required to improve the reliability of system. From all the possible reliability issues, the electrostatics discharge (ESD) might be the most common one. The peak current of electrostatics ...

In order to overcome the drawbacks associated with conventional bulk lithium niobate photonic, thin-film lithium-niobate-on-silicon has been pursued recently. This work presents contributions made to electro-, and nonlinear-optic applications of this technology. For electrooptic applications, detailed modeling and design guidelines of optical and radio-frequency parameters of ultracompact modul...

Blockchains enable secure asset exchange in a distributed system, thereby facilitating innovative applications such as cryptocurrencies and smart contracts. Although the cryptographic constructs of blockchains are highly secure, however, their practical deployments are vulnerable to various attacks due to their application-specific policies, and their peer-to-peer (P2P) network intricacies. In ...

A big challenge in blockchain and cryptocurrency is securing the private key from potential hackers. Nobody can rollback a transaction made with a stolen key once the network confirms it. The technical solution to protect private keys is the cryptocurrency wallet, software, hardware, or a combination to manage the keys. In this dissertation, we try to investigate the significant challenges in e...

Prognosis and health management play an important role in the control of costs associated with the operation of large industrial equipment. By properly comprehending hardware degradation and accurately predicting the remaining useful life of such equipment, we can significantly lower operational costs by reducing asset downtime and maintenance interventions. However, complex interactions betwee...

This thesis is devoted to designing and analyzing efficient text indexing data structures and associated algorithms for processing text data. The general problem is to preprocess a given text or a collection of texts into a space-efficient index to quickly answer various queries on this data. Basic queries such as counting/reporting a given pattern's occurrences as substrings of the original te...