The objective of this thesis is to determine a method for computing the amount of capacitance in a power electronic converter required to melt a fuse in the event of a line to ground fault. DC micro-grids rely on power electronic converters to change voltage levels. All converters rely on semiconductor switches that must be protected from surges of fault current. This limits the power that a converter can supply to a fuse. In many cases, sufficient power may be achieved by appropriately sizing the converters’ output capacitor. / text

Personality research has long been an area of interest in the study of consumer behavior. Currently, common practice is to segment prospective audiences by demographic variables (age, gender, and race) instead of psychographics (values, attitudes, personality). In this research, the author investigates the relationship between personality type (introversion/extraversion) and message recall. Using 122 undergraduate and graduate students, recall was examined across two forms of stimulus (incongruent and congruent messages). Results indicated that while there is no relationship between personality type and message recall, there is a relationship between the frequency of advertising messaging and recall. Results are discussed individually by messaging frequency and personality type with further suggestions for future research. / text

The use of feedback to provide channel state information to the transmitter can greatly improve the performance of a communication system. However, the amount of information required to characterize a time-varying MIMO channel can exceed the capacity of the feedback channel. This paper surveys research in limited feedback systems, which employ a number of methods to reduce the information and improve performance in multi-antenna communication systems. This paper also presents a new method, Quantized Successor Pre-coding (QSP), that exploits time-correlation to implement spatial multiplexing in a MIMO system using very little feedback. QSP uses an ordered codebook of pre-coders and transmission modes to reduce the feedback to a single bit. Simulations of QSP demonstrate a substantial performance improvement relative to open-loop spatial multiplexing. / text

Minimal research has been conducted to examine dissolution and remediation of NAPL located in lower-permeability (K) media. The purpose of this research was to investigate dissolution of non-uniformly distributed residual NAPL located in lower-K media and how mass transfer was affected. Additionally, in situ chemical oxidation (ISCO) effectiveness using KMnO₄ in the laboratory and field was examined. A series of column and flow cell experiments were conducted with trichloroethene (TCE). For uniformly distributed residual NAPL control experiments, reduced interfacial pool area and resonance time were likely the most important mass transfer limitation. For non-uniformly distributed residual NAPL, by-pass flow attributed to reduced effective permeability was initially the most important factor affecting nonideal mass transfer. Dissolution times increased with physical heterogeneity due to bypass flow. Mass transfer was more non-ideal for non-uniformly distributed NAPL. Nonideal mass transfer was most pronounced for non-uniformly distributed NAPL in lower-K zones. NAPL location influences dissolution behavior and ultimately remediation. Mass flux reduction versus mass reduction comparisons for the experiments exhibited how mass transfer trends vary between systems. The effectiveness of KMnO₄ ISCO of residual TCE located in lower-K media was examined. KMnO₄ solution was flushed through a flow cell followed by water flushing to evaluate long-term mass flux behavior, which was then compared to a water-flush control. For water flushing following KMnO₄ flushing, mass flux was similar to the control experiment. However, since contaminant mass was reduced, the number of pore volumes required for complete TCE removal via water flushing was estimated to be reduced by half. 1,1-Dichloroethene (DCE) is thought to be located in lower permeability strata adjacent to the water table at the Samsonite Building Area. Eight injection wells were emplaced in the source zone area, with well screens spanning the vadose and saturated zones, and injected with ~250 kg of 1.7% KMnO₄ solution. Bench-scale studies using core material determined that DCE was readily degraded by KMnO₄, even at lower reagent concentrations (< 1 mM). The natural oxidant demand was determined to be 1.0 x 10⁻⁵ g of KMnO₄/g of sediment. Aqueous DCE levels dropped below detection after KMnO₄ solution was present.

Cooperative effects in many-particle systems can be exploited to achieve measurement outcomes not possible with independent probe particles. We explore two measurement applications based on the cooperative phenomenon of superradiance or on correlated quantum states closely related to superradiance. In the first application we study the off-resonant superradiant Raman scattering of light from an ultracold Bose atomic vapor. We investigate the temperature dependence of superradiance for a trapped vapor and show that in the regime where superradiance occurs on a timescale comparable to a trap frequency, scattering takes place preferentially from atoms in the lowest trap levels due to Doppler dephasing. As a consequence, below the critical temperature for Bose condensation, absorption images of transmitted light serve as a direct probe of the condensed state. Subsequently, we consider a pure condensate and study the time-dependent spatial features of transmitted light, obtaining good qualitative agreement with recent imaging experiments. Inclusion of quantum fluctuations in the initial stages of the superradiant emission accounts well for shot-to-shot fluctuations. Secondly, we have used simulated annealing, a global optimization strategy, to systematically search for correlated quantum interferometer input states that approach the Heisenberg limited uncertainty in estimates of the interferometer phase shift. That limit improves over the standard quantum limit to the phase sensitivity of interferometric measurements by a factor of 1√N, where N is the number of interfering particles. We compare the performance of these states to that of other non-classical states already known to yield Heisenberg limited uncertainty.

Alzheimer’s disease is the most common cause of dementia and was responsible for over 2% of all deaths in Sweden 2012. One of the pathological hallmarks is amyloid plaques built by fibrillated Amyloid β. Luminescent conjugated oligothiophenes are known to stain and give characteristic fluorescence spectra when staining amyloid fibrils. Little is however known about the interactions between LCOs and fibrils. Studies have been performed on molecules more traditionally known to stain amyloid fibrils. Studies have also been performed on fibrils using limited proteolysis. So far no studies have been performed using LCOs combined with limited proteolysis in order to study the interaction pattern between LCOs and fibrils. Amyloid β is expressed and purified using a simple few step purification protocol. The amyloid β peptide was then fibrillated in several generations in order to select for a homogenous fibril structure. This purification protocol also has the ability to purify different oligomers of Amyloid β that are interesting from a toxicity point of view. In this thesis optical characteristics and limited proteolysis with mass spectrometry are being used to studies the interactions between LCOs and fibrillated amyloid β. The proteolytic pattern was suggestive of an accessible N-terminal and a hidden C-terminal of Amyloid β M1-42 in the fibril. It was also shown that the proteolysis cleavage pattern of Chymotrypsin is not disrupted when the LCO pKTAA was used to stain fibrils. The emission spectra from the two LCOs pATAA and pKTAA changes differently when subjected to continuous excitation indicative of conformational changes or chemical modification.

Due to difficulties associated with formulating complex models and obtaining reliable estimates of unknown model parameters, modellers often use simplified models (SMs) that are structurally imperfect and that contain a smaller number of parameters. The objectives of this research are: 1) to develop practical and easy-to-use strategies to help modellers select the best SM from a set of candidate models, and 2) to assist modellers in deciding which parameters in complex models should be estimated, and which should be fixed at initial values. The aim is to select models and parameters so that the best possible predictions can be obtained using the available data and the modeller’s engineering and scientific knowledge. This research summarizes the extensive qualitative and quantitative results in the statistics literature regarding the use of SMs. Mean-squared error (MSE) is used to judge the quality of model predictions obtained from different candidate models, and a confidence-interval approach is developed to assess the uncertainties associated with whether a SM or the corresponding extended model will give better predictions. Nine commonly-applied model-selection criteria (MSC) are reviewed and analyzed for their propensities of preferring SMs. It is shown that there exist preferential orderings for many MSC that are independent of model structure and the particular data set. A new MSE-based MSC is developed using univariate linear statistical models. The effectiveness of this criterion for selecting dynamic nonlinear multivariate models is demonstrated both theoretically and empirically. The proposed criterion is then applied for determining the optimal number of parameters to estimate in complex models, based on ranked parameter lists obtained from estimability analysis. This approach makes use of the modeller’s prior knowledge about precision of initial parameter values and is less computationally expensive than comparable methods in the literature. / Thesis (Ph.D, Chemical Engineering) -- Queen's University, 2009-12-23 09:48:45.423

Discrete-Event systems (DES) is a framework in which problems are modelled as finite-state automata and a solution in the form of a supervisory control scheme can be automatically synthesized via an exhaustive search through the state space of the system. Various extensions to the standard DES framework have been introduced to allow it to be applied to a greater variety of problems. When the system in question is very large or varies with time, a limited lookahead policy can be adopted, in which control decisions are made on-the-fly by looking at finite-step projections of the behaviour of the system's underlying automata. This work presents a new approach to limited lookahead supervision which incorporates many of the extensions to DES that are already present in the literature, such as event probability and string desirability. When dealing with a limited lookahead technique, the projected system behaviour is represented as a lookahead tree with some depth limit decided on by the user. It can be difficult to strike a balance between the complexities associated with storing and analyzing the trees and the amount of information available to make decisions, both of which increase with depth. This work also presents a set of methods which are designed to aid in accurately estimating the state space of lookahead trees with the intent of simplifying the process of determining a favourable depth to use. Finally, the approaches introduced herein are applied to a simulation of an infectious disease outbreak, primarily to showcase them in action, but also for the possibility of illuminating any useful information for real-world health units. / Thesis (Master, Computing) -- Queen's University, 2012-01-20 19:35:58.007

This study seeks to establish whether the introduction of new products between 1995 and 2003 created value for the customers and if the bank's key performance indicators such as profitability and market share improved as a result. The research also intends to identify the benefits and problems associated with development and introduction of new products in the banking sector, and whether or not the benefits are worth the effort and resources invested. Literature on segmentation, product development and customer care, from popular authors such as Kotler were applied. Subjects used were 29 Zimbabwe Banking Corporation Limited customers and 10 non-customers. The self-administered structured questionnaire, in conjunction with face-to-face interviews were used throughout the study. To ensure relevance and reliability of responses, only randomly selected companies and individuals were interviewed. Overall almost three quarters of the respondents affirmed that new products and refurbishments are effective because customer choice is increased, and that simply by introducing new products, the company shows an image of great customer focus. The introduction of new products and refurbishment of branches was also said to enhance the image of the bank. Others associated such changes with increased speed of service and better, more convenient products. Comparing the period before renovations with the one after, the new products introduced and branch refurbishments have had positive impact on the performance of ZIMBANK, as very significant improvements have been noted especially on the aspects of customer service, quality of products and increase in branch network. / Thesis (MBA)-University of Natal, Durban, 2003.

Globalisation and the intense competitiveness amongst businesses and countries has increased the importance of comparative stakeholder analysis and banks focusing on their corporate culture. Managers are now being required to look within their companies and are constantly seeking ways to move forward and grow their business. Banks have moved away from a financial motive to one focused on satisfying stakeholder wants and needs in order to satisfy needs externally. The aim of this thesis was to investigate and evaluate the cultural setting in which a bank in South Africa namely Standard Bank operates. Further, how this environment influences a stakeholder’s perspective, particularly employees and managers. Firstly, the thesis examines the literature that is separated into different parts. Initially, stakeholder theory and the needs and the motivations behind the different models adopted were analysed. Furthermore, in order to understand the interconnection between bank culture, stakeholder interests and perspectives, the different cultural dynamics at the site were studied and evaluated. This aided in developing a deeper understanding of conflicts arising from cultural issues, particularly in organisations with diverse cultures, such as Standard Bank. Secondly, a mixed methods approach was utilised in order to understand the interplay between the stakeholder perceptions and corporate culture. This approach facilitated the researcher in gaining richer insights and a broader perspective of the topic, further enhancing the study. Insights were drawn from visual diaries (5), questionnaires (35), in-depth interviews (2), and observations (1 day). This was done through combining the various elements of both quantitative and qualitative research methods. The study contributes to an understanding that, the unification of both managers and employees understanding of their cultural environment is instrumental to the success of an organisation. In order to do so, this starts with the way a company operates mainly its culture, values and belief systems within the organisation. Therefore, these values and beliefs affect how a company operates. Taking this into account helps to create a customer centred environment. These views may either be aligned or conflicting with organisational goals and values. Although, banks the world over have a unified banking system, each bank has its own value and belief systems in place which make it successful. / Thesis (M.Com.)-University of KwaZulu-Natal, Pietermaritzburg, 2013.