No description available.

This thesis analyzes the procedural approach and benefits of applying optimization techniques to the design of a boost power factor correction (PFC) converter with an input electromagnetic interference (EMI) filter at the component level. The analysis is performed based on the particular minimum cost design study of a 1.15 kW unit satisfying a set of specifications. A traditional design methodology is initially analyzed and employed to obtain a first design. A continuous design optimization is then formulated and solved to gain insight into the converter design tradeoffs and particularities. Finally, a discrete optimization approach using a genetic algorithm is defined to develop a completely automated user-friendly software design tool able to provide in a short period of time globally optimum designs of the system for different sets of specifications. The software design tool is then employed to optimize the system design, and the savings with respect to the traditional design methodology are highlighted. The optimization problem formulation in both the continuous and discrete cases is presented in detail. The system design variables, objective function (system component cost) and constraints are identified. The objective function is expressed as a function of the design variables. A computationally efficient and experimentally validated model of the system, including second-order effects, allows the constraint values (also as a function of the design variables) to be obtained. / Master of Science

It is important to investigate the threat posed to commercial aircraft by on board electronic transmitters in the passenger cabin and the cargo holds of large transport aircraft. These transmitters may be in the form of unintentional use of portable electronic devices or even intentional radio frequency (RF) threat sources from terrorists. Thus, it is of interest to determine the "interference path loss" (IPL) from a transmitting device inside the cabin of such aircraft to the antenna terminals of a potential victim system of the aircraft. Past studies have concentrated on measurements. These efforts to measure IPL directly have demonstrated that accurate and repeatible measurements are difficult to obtain. Very little modeling work has been done successfully to understand the IPL on aircraft. In this thesis, we propose a 3-step methodology to quantify the interference path loss (IPL). We then apply this methodology to a broad class of aircraft and show results. To validate our results, we compare our findings to known measurements and discuss possible sources of errors. Finally we suggest areas of improvement to our analysis and propose future work. / Master of Science

Electromagnetic compatibility (EMC) has become increasingly important in present electronic design. Modern high-speed circuitry has earned amplified attention from engineers due to its ability to interfere with neighboring circuitry through electromagnetic interference (EMI). As the operating speed and layout complexity of electronic circuit systems continues to increase, electromagnetic interference (EMI) becomes a serious issue facing circuit designers of the present and future. In this paper, the radiated emissions of a small PCB (including a microprocessor, SRAM, and flash memory) placed within a 1-GHz Crawford TEM (transverse electromagnetic) cell are analyzed. Various programs are executed while the microprocessor runs at different clock speeds. The dissimilarities in the radiated emission spectrums provided by the DUT (device under test) while running various programs at different clock speeds are compared and analyzed. All five programs run by the microprocessor show similar effects when the clock speed is varied. It is demonstrated that when the clock rate of the microprocessor increases, the overall radiation from the system increases. However, varying the software executed by the microprocessor is found to have effects on the emitted radiation pattern. The greatest noise within the radiated emission spectrum is found to come from programs in which the microprocessor communicates with the external SRAM chip. It is also found that the radiation levels for each program executed by the microprocessor change differently as the position of the microprocessor inside the TEM cell is varied. The fast paced lifestyle of modern society has undeniably led to an increase in desire for higher functionality of electronic devices. Whether it is a wireless device, a portable computer, or simply more electronic components inside an automobile, the need for electronics with more capabilities has become a standard in electronic design. However, to increase the function of a digital device, clock frequencies and software have to be altered. It is hoped that this paper will help engineers to take into consideration how changes in clock frequencies and software can affect the radiated EMI within their designs. An engineer's consideration of the effects of EMI within his/her design will help lead to safer, more reliable devices.

Yes / Hot melt extrusion has been used to produce a solid dispersion of the thermolabile drug artemisinin. Formulation and process conditions were optimised prior to evaluation of dissolution and biopharmaceutical performance. Soluplus®, a low Tg amphiphilic polymer especially designed for solid dispersions enabled melt extrusion at 110ºC although some drug-polymer incompatibility was observed. Addition of 5% citric acid as a pH modifier was found to suppress the degradation. The area under plasma concentration time curve (AUC0-24hr) and peak plasma concentration (Cmax) were four times higher for the modified solid dispersion compared to that of pure artemisinin. / EPSRC grant no (EP/J003360/1) and UKIERI: UK-India Education and Research Initiative (TPR 26).

Electromagnetic compatibility (EMC), or the field of reducing emissions from and increasing immunity against electromagnetic interference, is an essential part of designing modern electronics. As one would expect, EMC is especially important for things such as aircraft and aviation equipment where outages or disturbances could have severe consequences. The problem presented in this thesis was to consolidate the available legislation regarding EMC for unmanned aircraft and then apply this information onto two commercial systems still under development. Based on the applied rules, pre-compliance measurements were then performed to identify problematic areas of their designs in regards to EMC, or more specifically radiated emissions and electromagnetic immunity. The research process for the legislation involved reading through mainly the official documents and directives published by the European Commission, the European Parliament and the European Aviation Safety Agency (EASA), looking up declarations of conformity made by drone manufacturers and also contacting accredited EMC labs for information on how they usually prove compliance for drones. The conclusion of this research being that (for EMC purposes) drones need to follow either the EMC directive 2014/30/EU, the radio equipment directive 2014/53/EU or the essential requirements of directive 2018/1139/EU depending on the intended usage of the drone and its technical specification. As for application of legislation onto the two commercial systems, because there were no drone-specific EMC standards (i.e voluntary ways to more easily prove conformity) in the EU some simplifications would need to be made. This took the form of applying parts of both the EN 55032 (applicable for multimedia equipment) and EN 301 489-1 (applicable for radio equipment) standards for radiated emissions and immunity testing respectively. While the application of legislation in the end was more simplified than initially planned, the goal of condensing down the available information was still achieved. As for the measurements, it should be noted that while most of the problematic areas that caused the systems to break the limits in the chosen legislation were indeed successfully identified on both systems there are still measurements that should be done in the future. This includes testing conducted emissions and immunity against transient electromagnetic phenomena such as electrostatic discharge (ESD).

published_or_final_version / Management Studies / Doctoral / Doctor of Philosophy

The present study is a longitudinal exploration of problems and satisfaction in the marriages of 60 participants. The Marriage Adjustment and the Confidential questionnaire were administered to these participants in 1973 and again in 1981, and their results were examined both descriptively and empirically for female/male differences in patterns of problems and satisfaction. In terms of empirical findings, eight hypotheses used either t-tests for dependent means or Pearson Product Moment Correlation Coefficients to test the frequency of problem endorsement relating to patterns of increase, persistence, and covariation with satisfaction levels. Satisfaction patterns over time and female/male differences were also explored. Females in the study showed significant increases in numbers of problems over time, whereas males did not. Females also showed significant decreases in satisfaction levels, whereas males did not. Both females and males showed an inverse relationship between number of problems and level of satisfaction in 1981, but not in 1973. Both females and males showed a relationship between frequency of problems endorsed in 1973 and the number of those problems persisting in 1981. There were no significant differences between female and male satisfaction ratings. In terms of descriptive findings, several research questions explored the content of most prevalent problems and problem categories in each year and persisting with time. Sex and communication problems were the highest ranked categories in both years for both sexes, and tended to persist and increase in number with time.

A global schema is an integrated view of heterogeneous databases used to support data sharing among independent, existing databases. Global schema design complexities arise from the volume of details, design choices, potential conflicts, and interdependencies among design choices. The methodology described provides a framework for efficient management of these critical dimensions in generating and evaluating alternative designs. The methodology contains three major steps. First, differences due to the varying local data models are resolved by converting each local schema to an equivalent schema in a unifying data model. Second, the entity types of the local schemas in the unifying model are grouped into clusters called common areas. All the entity types in a common area can possibly be merged via generalization. For each common area, semantic information is defined that drives the merging process. Third, each common area is integrated into the global schema by applying a set of generalization operators. Mapping rules are then defined to resolve differences in the representations of equivalent attributes. Th integration of the local schemas is based on equivalence assertions. Four types of attribute equivalences are defined: two attributes may be locally or globally equivalent, and they can be key or non-key. Strategies for handling each of these cases are proposed and evaluated. The global schema design methodology includes several algorithms which may assist a designer. One algorithm analyzes a set of equivalence assertions for consistency and completeness including resolution of transitively implied assertions. A second algorithm performs an interactive merge of a common area by presenting the possible generalization actions to the designer. It supports the theme that many generalization structures can be possible, and the appropriate structure often depends on designer preferences and application requirements. The methodology is evaluated for several cases involving real databases. The cases demonstrate the utility of the methodology in managing the details, considering many alternatives, and resolving conflicts. In addition, these cases demonstrate the need for a set of computer-aided tools; for even a relatively small case, the number of details and design choices can overwhelm a designer.

Despite recent increasing interest in the existence of animal personality, i.e. intra-individual consistency and inter-individual variation in the level of a behavioural trait, the evolutionary (and ecological) consequences of these consistent behavioural differences remain poorly understood. Some recent studies have revealed that variation in animal personalities might be linked to competitive interactions, resulting from natural selection. However, since personalities might similarly affect mate acquisition and reproductive success, it seems crucial to also explore their evolution under the framework of sexual selection theory. In this thesis I investigate the influence of personality on mate choice, reproductive success, female-male and male-male interactions, using zebra finches, Taeniopygia guttata, as a model species. After (I) I review the few existing studies assessing the link between sexual selection and personality, I propose a framework on the relationship between sexual selection and personality. Subsequently, (II) I show with different experimental approaches for the first time that (a) females choose males on the basis of their behaviour per se (male behaviour was experimentally disentangled from any appearance effects) whilst considering their own personality in their choice: less exploratory females did not distinguish between exploratory and non-exploratory appearing males, whereas moderately and highly exploratory females preferred similar males. (b) These preferences have an adaptive value to the exploratory females: exploratory females which had a behaviourally similar partner raised chicks in best condition but chicks in worst condition if they had a dissimilar partner. Low exploration females always raised chicks in intermediate condition, which may explain why they did not choose males on the basis of their exploratory behaviour. (c) I provide evidence that the combination of personalities in a pair, not only in terms of the level of the behaviour but also in terms of the behavioural consistency, influence reproductive success. However, this was only true for foster but not genetic parents, suggesting that behavioural rather than genetic compatibility (for the measured personality traits) is important for reproduction. (d) Moreover, some male behavioural characteristics appear to be a signal of male quality: highly exploratory foster males raised chicks (both males and females) in best condition, which themselves raised foster chicks of increased conditions. (e) Furthermore, a number of sex differences in personality traits (both level and consistency) are identified, including different responses to social interactions. (f) Additionally, I show how females with different exploratory tendencies differ in their movement patterns during mate choice. (g) Finally, I demonstrate that in competitive male-male situations, a measurement of condition, the fat score, and aggressive behaviour are positively correlated. These findings are set into sexual selection context (but other evolutionary processes are also considered) and both their ecological and evolutionary consequences are discussed. I outline how these results make a valuable contribution to the research field and discuss their potential to indicate new directions for future studies.