This dissertation addresses fault detection and isolation (FDI) for nonlinear systems based on models using two different approaches. The first approach detects and isolates single and multiple faults, particularly when there are restrictions in measuring process variables. The FDI model-based method is based on nonlinear state estimators, in which the estimates are calculated under high filtering, and a high fidelity residuals model, obtained from the difference between measurements and estimates. In the second approach, a robust fault detection and isolation (RFDI) system, that handles both parameter estimation and parameters with uncertainties, is proposed in which complex models can be simplified with nonlinear functions so that they can be formulated as differential algebraic equations (DAE). In utilizing this framework, faults are identified by performing a statistical analysis. Finally, comparisons with existing data-driven approaches show that the proposed model-based methods are capable of distinguishing a fault from the diverse array of possible faults, a common occurrence in complex processes. / text

Les bases de données présentent des problèmes de passage à l’échelle. Ceci est principalement dû à la compétition pour les ressources et au coût du contrôle de la concurrence. Une alternative consiste à centraliser les écritures afin d’éviter les conflits. Cependant, cette solution ne présente des performances satisfaisantes que pour les applications effectuant majoritairement des lectures. Une autre solution est d’affaiblir les propriétés transactionnelles mais cela complexifie le travail des développeurs d’applications. Notre solution, Gargamel, répartie les transactions effectuant des écritures sur différentes répliques de la base de données tout en gardant de fortes propriétés transactionnelles. Toutes les répliques de la base de donnée s’exécutent séquentiellement, à plein débit; la synchronisation entre les répliques reste minime. Les évaluations effectuées avec notre prototype montrent que Gargamel permet d’améliorer le temps de réponse et la charge d’un ordre de grandeur quand la compétition est forte (systèmes très chargés avec ressources limitées) et que dans les autres cas le ralentissement est négligeable. / Databases often scale poorly in distributed configurations, due to the cost of concurrency control and to resource contention. The alternative of centralizing writes works well only for read-intensive workloads, whereas weakening transactional properties is problematic for application developers. Our solution spreads non-conflicting update transactions to different replicas, but still provides strong transactional guarantees. In effect, Gargamel partitions the database dynamically according to the update workload. Each database replica runs sequentially, at full bandwidth; mutual synchronisation between replicas remains minimal. Our prototype show that Gargamel improves both response time and load by an order of magnitude when contention is high (highly loaded system with bounded resources), and that otherwise slow-down is negligible.

No description available.

A primary concern in the geologic storage of anthropogenic carbon dioxide is the leakage of buoyant CO₂ plumes into shallower formations, aquifers, or the surface. Man-made wells drilled through these formations present a potential leakage pathway for this CO₂ as the cement binding the well to the earth develops fractures or debonded microannuli form over time. Typically, wells with poor cementing or suspected leaks are subject to a cement-squeeze, in which new cement is injected to eliminate the leakage pathway. However, small fractures or leakage pathways are often difficult for oilfield cement to repair, as the cement dispersion is potentially screened out from dispersing fluid and cannot enter the fracture. Therefore a low-viscosity sealant is desired that can enter these leakage pathways easily and provide a robust seal. A class of poly(acrylic acid) polymers known commercially as Carbopol® are pH-sensitive microgels and swell/thicken upon neutralization with alkali cement components. These polymer dispersions are tested for ease of placement into cement fractures and subsequent development of resistance to displacement. Laboratory experiments involved injecting various unswollen polymer microgel dispersion into constructed cement fractures while measuring injection pressure and the pH of the polymer effluent to quantify the chemical reactions taking place and the induced viscosity changes. Fractures were constructed in order to allow for visual inspection of the polymer microgel swelling during and after injection, qualitatively useful in determining the polymer’s efficiency at blocking cement fractures. It was determined that polymer microgels undergo syneresis in the presence of calcium cations that are dissolved from minerals present in cement. The syneresis causes the polymer to collapse onto the cement fracture face and expelled water is left to fill the rest of the fracture, providing little to no resistance to subsequent flow. However, the syneresed polymer does show some potential in blocking or partially blocking small aperture fractures and is not entirely detrimental to fracture blockage in small amounts. An acid pre-flush prior to polymer injection has been seen to favorably reduce the amount of calcium and therefore extent of syneresis, allowing swollen polymer microgels to remain intact and block fluid flow. / text

This investigation was concerned with the relationship between loneliness and disability in individuals with back and spinal cord injury. Specifically, the purpose of this study was to answer the following questions: (1) Do disabled individuals report a greater degree of loneliness than an able-bodied control group? (2) Does loneliness relate to the level of expressed need for inclusion and affection? (3) Does locus of control relate to the degree of loneliness reported by individuals with disability? (4) Does the employment status or living arrangement of disabled individuals relate to the degree of reported loneliness? (5) Does the short form of the Revised UCLA Loneliness Scale provide a reliable estimate of the full-scale form in the measurement of loneliness in disabled individuals? The population for this study consisted of thirty spinal-injured paraplegics, thirty back-injured patients, and fifty able-bodied control subjects. The criterion instruments employed in this study were the Revised UCLA Loneliness Scale, the Fundamental Interpersonal Relations Orientation-Behavior, and the Rotter Internal-External Locus of Control Scale. Survey packets were mailed to the spinal-injury and back-injury subjects. Able-bodied controls were administered the same packet in a group-classroom setting. The data was analyzed by Pearson Product-Moment correlation, point bi-serial correlation, One Way Analysis of Variance, and Student t-test. The significance level for this investigation was set at .05. Based on the results of the statistical analyses, the following conclusions were drawn: (1) Paraplegics did not significantly differ from back-injured patients, or an able-bodied control group, on the measure of Loneliness. (2) A significant correlation (negative) was found between loneliness and the expressed need for inclusion and affection in the spinal-injured group. (3) A significant relationships between loneliness and employment status or living arrangement was not found. (4) Spinal-injured paraplegics rated as externals on the locus of control measure were significantly higher than those subjects rated as having an internal locus of control on the measure of loneliness. (5) The short-form of the Revised UCLA Loneliness Scale was significantly, (positively), correlated with the full-form in all subject groups.

No description available.

No description available.

No description available.

The thesis examines isolation and caritas, or charity, in The Confidence-Man as polar themes which express, respectively, withdrawal from and suspicion of the human community and integration within and appreciation for that community. Isolation is considered a negative theme; caritas, an affirmative theme.

Background: South Africa is a diverse country in terms of its cultures, languages, socioeconomic variety and community beliefs and this is reflected in our health care setting. Communication is a critical feature of adequate medical care and an understanding of potential barriers to communication is important particularly in understanding under-resourced rural health care settings. The health community is comprised of different professionals who are required to communicate interdependently on a daily basis to ensure the best quality of care for their patients. Little research has been done on the role of interprofessional communication in a rural setting. Purpose: The aim of this research project is to describe and understand the influence of systemic and interpersonal factors on communication processes between health care professionals working in a rural hospital context. Method: The research study used a qualitative design and the application of social interaction theory, specifically Goffman’s framework was used to understand the phenomena studied. The study involved 52 health professionals and included: doctors, nurses, clinical associates, social workers, pharmacists, dieticians, physiotherapists, occupational therapists, speech and language therapists, audiologists and administrative staff. The data in this research were derived from ethnographic observations in the hospital, and focus groups and interviews with participants. Profession-specific vignettes were used during the focus groups to stimulate discussion. A SiSwati speaking research assistant helped with the collection of data and aided in translation and transcriptions. Data from the 52 interviews, 8 detailed xiv observations and 12 focus groups were analysed using thematic analysis. Findings: Numerous systemic and interpersonal themes were derived from the data. The study found that health care professionals felt isolation from both the wider medical community as well as the local community which influenced interprofessional communication. Systemic influences included the impact of the rural setting, changes in health systems (the proposed National Health Insurance scheme) and access to provincial support. Interpersonal themes included management, power, responsibility, handover, recognition of roles, blame, conflict and language issues. One of the most prominent interpersonal themes to emerge was the identity of the health care worker which was interlinked with their professional role, status, power, race, language and community identity. Participants’ thoughts about the way forward for the hospital also emerged. Conclusion & implications: Systemic and interpersonal factors do influence health care workers’ interprofessional communication. Social interaction theory explains some of the complex communication interactions but they do not account for important systemic influences. Goffman’s front and backstage is beneficial in identifying communication in a rural hospital however systemic and interpersonal categories were found to be more useful in this setting. The implications from this study are important for policy, theory and practice such as communication training programmes for rural healthcare teams as well as site specific models of training. Speech and language therapists are communication experts and therefore could be playing a greater role in the development of team communication.