This thesis considers the design of cascaded SISO control systems using the H∞ and QFT methodologies. In the first part of the thesis the actual advantages offered by Single Input Single Output (SISO) cascade loop structures are studied. In Quantitative Feedback Theory(QFT) it is emphasized that the use of cascaded loops is primarily for the reduction of bandwidth of the controllers. This in turn helps in considerable reduction of the adverse effects of high frequency noise. The question that arises then is whether or not there are any substantial benefits to be gained by cascade loop design in the low frequencies. It is shown using QFT methodology that there aren’t any advantages gained in the low frequencies with the use of cascaded design. In effect it is concluded that if the design is properly executed a single loop controller closed from the output to the input will be sufficient to meet the typical performance specifications. This is shown using an example where the mold level of a continuous casting process is to be controlled. The plant being used has considerable uncertainty so that features of robust control can be highlighted. In the second part the Robust Outer Loop bounds were generated analytically and examined for certain properties. It was compared to the bounds generated by already existing algorithms. In the third part the inner outer QFT design was modified with the inner loop being designed using H∞ with the concept of sensitivity shaping. This design was very similar to the pure QFT design with the added advantage of having some automation. In the fourth part the H∞ methodology was used to design a two loop control structure. The idea was to compare this design to the QFT design. It was seen that H∞ generated redundant controllers and pre filters.

Historical evidence has shown that incidents due to hazardous materials (HazMat) releases during transportation can lead to severe consequences. The public and some agencies such as the Department of Transportation (DOT) show an increasing concern with the hazard associated with HazMat transportation. Many hazards may be identified and controlled or eliminated through use of risk analysis. Transportation Risk Analysis (TRA) is a powerful tool in HazMat transportation decision support system. It is helpful in choosing among alternate routes by providing information on risks associated with each route, and in selecting appropriate risk reduction alternatives by demonstrating the effectiveness of various alternatives. Some methodologies have been developed to assess the transportation risk; however, most of those proposed methodologies are hard to employ directly by decision or policy makers. One major barrier is the lack of the match between available data/database analysis and the numerical methodologies for TRA. In this work methodologies to assess the transportation risk are developed based on the availability of data or databases. The match between the availability of data/databases and numerical TRA methodologies is pursued. Each risk component, including frequency, release scenario, and consequence, is assessed based on the available data/databases. The risk is measured by numerical algorithms step by step in the transportation network. Based on the TRA results, decisions on HazMat transportation could be made appropriately and reasonably. The combination of recent interest in expanding or building new facilities to receive liquefied natural gas (LNG) carriers, along with increased awareness and concern about potential terrorist action, has raised questions about the potential consequences of incidents involving LNG transportation. One of those consequences, rapid phase transition (RPT), is studied in this dissertation. The incidents and experiments of LNG-water RPT and theoretical analysis about RPT mechanism are reviewed. Some other consequences, like pool spread and vapor cloud dispersion, are analyzed by Federal Energy Regulatory Commission (FERC) model.

Autoland controllers are prevalent for both large and small/micro unmanned aerial vehicles, but very few are available for medium sized unmanned aerial vehicles. These vehicles tend to have limited sensors and instrumentation, yet must possess good performance in the presence of modeling uncertainties, and exogenous inputs such as turbulence. Quantitative Feedback Theory is an attractive control methodology for this application, since it provides good performance and robustness for systems with structured model uncertainties. It has been successfully applied to many aircraft problems, but not to automatic landing, and only inner-loop synthesis has been presented in the literature. This paper describes the synthesis and development of an automatic landing controller for medium size unmanned aerial vehicles, using discrete Quantitative Feedback Theory. Controllers for the localizer, glideslope tracker, and automatic flare are developed, with a focus on the outer-loops synthesis. Linear, non real-time six degree-of-freedom Monte Carlo simulation is used to compare the Quantitative Feedback Theory controller to a baseline Proportional-Integral controller in several still air and turbulent landing scenarios. The Quantitative Feedback Theory controller provides performance similar to the Proportional-Integral controller in still and in turbulent air. Both controllers show similar robustness to turbulence, but the Quantitative Feedback Theory controller provides significantly better robustness to model uncertainties in turbulent air as well as to sensor characteristics in turbulence. Based on the results of the paper, the QFT controller is a promising candidate for an autoland controller.

Thèse de doctorat : CHIMIE : Metz : 1999. / 1999METZ015S. 105 ref.

The development of a child can be monitored by studying the changes in physical appearance or the development of capabilities e.g. walking and talking. But is it possible to find a quantitative measure for brain development? The aim of this thesis work is to investigate that possibility using quantitative magnetic resonance imaging (qMRI) images by answering the following questions: Can brain development be determined using qMRI? If so, what properties of the brain can be used? Can the age of a child be automatically detected with an algorithm? If so, how can this algorithm function? With what accuracy? Previous studies have shown that it is possible to detect properties in the brain changing with age, based on MRI images. These properties have e.g. been changes in T1 and T2 relaxation time, i.e. properties in water signal behavior that can be measured using multiple MR acquisitions. In the literature this was linked to a rapid myelination process that occurs after birth. Furthermore the organization and growth of the brain is a property that can be measured and monitored. This thesis have investigated several different properties in the brain based on qMRI images in order to identify those who have a strong correlation with age in the range 0-20 years. The properties that were found to have a high correlation were: Position of the first histogram peak in T1 weighted qMRI images, Fraction of white matter in the brain, Mean pixel value of PD weighted qMRI images, Volume of white matter in the brain, Curves on the form f(x) = ae^(-bx) +c are fitted to the data sets and confidence intervals are calculated to frame the statistical insecurity of the curve. The mean error in percent for the different properties can be seen in the list below: Property, Mean error [%] 0-20 years, Mean error [%] 0-3 years Peak position: 53.84, 98.17 Fraction of WM: 118.97, 71.67 Mean pixel value: 200.89, 126.28 Volume of WM: 241.72, 72.58 The conclusions drawn based on the presented results are that there are properties in the brain that correlates well to aging, but the error is too large for making a valid prediction of age over the entire range of 0-20 years. When decreasing the age range to 0-3 years the mean error becomes smaller, but it is still too large. More data is needed to evaluate and improve this result.

<p>The petrochemical field is an industry seeking to increase efficiency, improve safety of workers, and lessen environmental impacts (U.S. Chemical Safety & Hazard Investigation Board, 2007). One way to improve the performance of operators is to investigate their situation awareness (SA). Research has shown that SA is a predictor of performance (Durso et al., 1999). However, there is little consensus on how to measure SA. This study investigated two prominent techniques for measuring SA: the Situation Present Assessment Method (SPAM; Durso & Dattel, 2004) and the Situation Awareness Global Assessment Technique (SAGAT; Endsley, 1995b). These two techniques were examined for their psychometric properties in assessing SA among operators. The results of this investigation showed that probe-type SA techniques can be used to assess SA in this field. This especially applies to the SPAM technique, which was shown to predict performance, not intrude, and was preferred by a majority of operators.

published_or_final_version / Electrical and Electronic Engineering / Master / Master of Philosophy

<p> The Fullerton Ontological Confusion (FOC) scale was constructed to address the issues of inconsistent theory and inadequate measurement regarding paranormal, superstitious, magical, and supernatural (PSMS) beliefs. For the FOC scale, PSMS beliefs were defined as confusions of ontology, or the misattribution of core knowledge belief categories. The FOC was empirically evaluated under an Item Response Theory framework using the nominal response model (NRM) to estimate item parameters and the Wald test to evaluate within-item category variation. Using the NRM and the Wald test, the FOC scale items were revised to yield a measure that was optimally formatted and informative. Correlational analysis was used to validate the FOC scale by testing the hypothesized relationships to theoretically related and unrelated constructs. The FOC scale was found to have a good degree of validity with most of the testable validation hypotheses being supported. Compared to the available existing measures, the FOC scale could be used as a more pure and informative measure for PSMS beliefs. </p>

Heartwater is a tick borne disease that affects ruminants and wild animals in Africa south of the Sahara. It is caused by Ehrlichia ruminantium and transmitted by the tick Amblyomma hebraeum. The protocols currently used to detect heartwater take several days to complete. Here, we describe the development of a pCS20 quantitative real-time PCRTaqMan probe assay to detect E. ruminantium in livestock blood and ticks from the field. The assay is based on the conserved pCS20 gene region of E. ruminantium that contains two overlapping genes, rnc and ctaG [Collins, N.E., Liebenberg, J., De Villiers, E.P., Brayton, K.A., Louw, E., Pretorius, A., Faber, F.E., Van Heerden, H., Josemans, A., Van Kleef, M., Steyn, H.C., Van Strijp, M.F., Zweygarth, E., Jongejan, F., Maillard, J.C., Berthier, D., Botha, M., Joubert, F., Corton, C.H., Thomson, N.R., Allsopp, M.T., Allsopp, B.A., 2005. The genome of the heartwater agent Ehrlichia ruminantium contains multiple tandem repeats of actively variable copy number. PNAS 102, 838–843]. The pCS20 quantitative real-time PCRTaqMan probe was compared to the currently used pCS20 PCR and PCR/32P-probe test with regards to sensitivity, specificity and the ability to detect DNA in field samples and in blood from experimentally infected sheep. This investigation showed that the pCS20 quantitative real-time PCRTaqMan probe was the most sensitive assay detecting seven copies of DNA/ml of cell culture. All three assays, however, cross react with Ehrlichia canis and Ehrlichia chaffeensis. The pCS20 real-time PCR detected significantly more positive field samples. Both the PCR and pCS20 real-time PCR could only detect E. ruminantium parasites in the blood of experimentally infected sheep during the febrile reaction. The PCR/32P-probe assay, however, detected the parasite DNA 1 day before and during the febrile reaction. Thus, because this new quantitative pCS20 real-time PCRTaqMan probe assay was the most sensitive and can be performed within 2 h it is an effective assay for epidemiological surveillance and monitoring of infected animals.

<p> The overarching goal of psychoanalytic and narrative therapies is to increase agency; however, few tools assess for agency. The Personal Agency Questionnaire (PAQ) was developed for this purpose and was found to be a valid and reliable instrument (Lundquist, 2012). The primary aims of this study were to (a) replicate past findings by performing correlations between the PAQ and scales measuring constructs thought to be part of agency (RSES for self-esteem; GSE for self-efficacy, and IPC for internal locus of control), (b) increase internal consistency and reliability of the PAQ through performing a factor analysis, and (c) establish additional validity by performing regressions to determine how three additional variables were related to agency: gender, perception of being overweight, and antifat attitudes. Females were expected to score lower than males on the PAQ because of the influence of gender norms on agency. Overweight status has shown a negative relation to agency, self-efficacy, and self-esteem; however, the fat- accepting individuals were expected to have greater agency compared to those who have internalized the culture&rsquo;s antifat messages. Participants accessed the online survey through postings on Craig&rsquo;s List and Yahoo discussion groups. Analyses were conducted with 280 participants, a majority of whom were White (65%), female (74%), employed (59%), highly educated (64% had college degree or greater, 33.20% attended some college), and had attended therapy (68%). Factor analysis revealed 4 factors underlying the PAQ (which replaced the previously hypothesized 6 subscales); items of the PAQ were reduced from 42 to 24, increasing reliability among the factors, with &alpha; = .78, &alpha; = .78, &alpha; = .72, &alpha; = .73, and the total reliability from &alpha; = .62 to &alpha; = .90. The new PAQ had stronger correlations than previously with the three scales that established its construct validity. Fat acceptance, age, education and therapy were significantly, positively correlated with agency. When looking at gender alone, or perceptions of being fat alone or in combination with gender, no differences in agency were evident. However when adding the antifat variable to gender and perceptions of being overweight, being female, significantly overweight, with antifat attitudes predicted reduced agency.</p>