The non-local stabilization of nonlinear systems by output feedback is a challenging problem that remains the subject of continuing investigation in control theory. In this thesis we develop two globally asymptotically stabilizing output feedback algorithms for multivariable nonlinear systems. Our first result is an extension a well-known output feedback method to a class of nonlinear systems whose dynamics can be written as a collection of subsystems that are dynamically coupled through output-dependent nonlinear terms. We show that this method must be modified to accommodate the dynamic coupling by introducing additional nonlinear damping terms into each control input. Our second contribution involves the application of observer backstepping to systems in a restricted block-triangular observer form. In this form, the nonlinearities entering each subsystem are allowed to depend on the output associated with the subsystem, and all upper subsystem states, including unmeasured ones. The proposed algorithm is demonstrated on a magnetically levitated ball. / Controls

The impetus for this study grew from observations in clinical practice that many individuals survived all sorts of hardships with minimal distress, or with the ability to tolerate their distress, and move on with their lives in a positive manner. A review of the literature led to the conclusions that the research investigating resilience was making minimal inroads into understanding what made these people different, and that the richness of who they were was being lost in the scientific process. This dissatisfaction led to the decision to explore the construct from a phenomenological framework, and to try and discover the essential elements of resilience through analysis of the subjective experience of resilience. A qualitative study involving thirteen participants identified by their peers as resilient was undertaken and the underlying themes of their stories were analysed. This led to the development of a model of resilience that attempted to balance the need for parsimony with that of explanatory breadth, and which had the potential to tolerate the complexity and instability of the construct itself. The model developed identified three core elements that embraced the construct of resilience. These included the physiological capacity to be resilient, and from this basis the ability to be adaptive and the ability to maintain well-being emerge. Factors identified with these elements include individual reactivity to and recovery from adverse events, the ability to be effective and efficient in the management of adverse events, and the beliefs about the world and the self that promote well-being when exposed to adverse events. The model has a basis within neurobiology and is framed within the context of Dynamic Systems Theory. The theory itself is a culmination of clinical observations with what is known from within the current literature and the results of this study.

Thesis (M.H.A.)--University of Michigan, 1962.

Thesis (M.H.A.)--University of Michigan, 1962.

The capability of organizations to respond to unexpected events has been investigated from different theoretical angles: organizational learning, improvisation, ambidexterity, resilience, to name but a few. These concepts, however, hardly ever refer to structural characteristics. Against this backdrop, the aim of this paper is twofold. First, based on systems and organizational learning theory, it will theoretically link the characteristics of organizational structure with organizational responses to unexpected external jolts, thus contributing to better understand the reactions of organizations to the unexpected. Second, it will empirically illustrate the relation of organizational structure with organizational responses by investigating how Civil Society Organizations (CSOs) in Austria reacted to the unexpected inflow of refugees from Central Europe. In 2015, CSOs accepted a wide range of responsibilities and worked together with government entities to provide shelter, catering, and transport for almost one million refugees. Based on participant observations during opera- tion, in-depth interviews (2015 and 2016) and focus groups with decision-makers (2017), we will sketch three longi- tudinal case studies of organizations with very different structures, concentrating on the processes and operations they developed during the crisis. Our findings show that their responses are closely related to their structure, specifically to the flexibility and the stability of structural elements. Remarkable changes took place in all organizations investigated. Initial responses and first structural changes occurred mainly where the structure already allowed for flexibility. Yet in the long run, the adaptations also impacted the stable structural elements.

The purpose of this study is to examine instances of naturally occurring conversations between twin siblings. This study uses both conversation analysis and semi-structured interviews to investigate communication patterns and practices in everyday twin-to-twin talk. The following research questions guided this study: (1) What pragmatic features of analytic interest are present in twin-to-twin talk? (2) What pragmatic features of analytic interest are present when twins interact with other members of the family system? There were a total of six sets of twin siblings between the ages of 10 and 15 who engaged in participant self-taping and semi-structured interviews. Although it did not have an observable effect on the findings, there were five sets of dizygotic (fraternal) twins and one set of monozygotic (identical) twins. Eight parents were interviewed and four parents participated in the conversations with the twin siblings. Findings suggest that certain communication practices and Phenomena are present in twin siblings' conversations, though not necessarily uniquely. Simultaneous speech is a conversational practice evident in every set of twin siblings' transcripts, serving as a completion to the other's utterance. In the presence of parents, it functions as a competitive move, other-initiated repair, and entertainment. As the twins conversed alone, extension/completion of the other twin's utterance served as a way to verify reported speech. It functions as support, verification, competition, and a way to gain attention when talking in front of a parent. The joint conversational performance act of code-switching was a practice used for entertainment by the twins when conversing alone. It served as a way to prove a point and to entertain as they interacted with a parent. Conversational phenomena included testing, and speaking for one's twin. Twins engaged in testing while conversing alone to show support for their twin. As they engaged in talk with a parent present, it served as competition/support, role confirmation/enactment, and identification/deidentification between the twin siblings. Speaking for one's twin could only occur while the twins were conversing in front of a parent. It functioned as a competitive move, as support, and as a way to gain attention.

Over the past two decades, holistic and systemic approaches to second language development have begun to draw the attention of scholars in the field of SLA. These studies are primarily informed by complexity theory, which emerged from the general systems theory. General systems theory, however, has another important theoretical offshoot in social sciences, namely autopoietic systems theory. An investigation of conceptual tools drawn from the latter theory has been absent in the field of second language education. This paper seeks to explore how systemic thinking has improved the field’s understanding of the complexity of the L2 development. It then explores the possibilities for incorporating autopoietic systems theory into complexity thinking to better understand the dynamics of L2 development at personal and social levels. Finally, it will highlight two insights from a systemic analysis of language development in L2 classroom groupings. These insights build on each other to describe L2 development from a systemic perspective. By exploring and bringing together these theoretical perspectives, this paper hopes to shed light on how complexity theory can provide a systemic description of L2 development.

Abstract In this thesis a set of new algorithms is introduced for Iterative Learning Control (ILC) and Repetitive Control (RC). Both areas of study are relatively new in control theory, and the common denominator for them is that they concentrate on controlling systems that include either reference signals or disturbances which are periodic. This provides opportunities for using past information or experience so that the control system learns the control action that results in good performance in terms of reference tracking or disturbance rejection. The first major contribution of the thesis is the algebraic analysis of ILC systems. This analysis shows that in the discrete-time case ILC algorithm design can be considered as designing a multivariable controller for a multivariable static plant and the reference signal that has to be tracked is a multivariable step function. Furthermore, the algebraic analysis reveals that time-varying algorithms should be used instead of time-invariant ones in order to guarantee monotonic convergence of the error in norm. However, from the algebraic analysis it is not clear how to select the free parameters of a given ILC algorithm. Hence in this thesis optimisation methods are used to automate this design phase. Special emphasis is placed on the so called Norm-Optimal Iterative Learning Control (NOILC) that was originally developed in (Amann:1996) as a new result it is shown that a convex modification of the existing predictive algorithm will result in a considerable improvement in convergence speed. Because the NOILC algorithm is computationally quite complex, a new set of Parameter-Optimal ILC algorithms are derived that converge under certain assumptions on the original plant. Three of these new algorithms will result in monotonic convergence to zero tracking error for an arbitrary discrete-time, linear, time-invariant plant. This a very strong property that has been earlier reported for only a small number of ILC algorithms. In the RC case it is shown that an existing RC algorithm that has been widely analysed and used in the research literature is in fact highly unrobust if the algorithm is implemented using sampled-data processing. Consequently, in this thesis a new optimality based discrete-time RC algorithm is derived, which converges to zero tracking error asymptotically for an arbitrary linear, time-invariant discrete-time plant under mild controllability and observability conditions.

Magister Artium (Psychology) - MA(Psych) / Supportive relationships have been found to be very beneficial for health and well-being. However, amongst alcohol dependent individuals, family support is often low, as alcohol abuse can pose a barrier between the individual and his or her family. The aim of this study was to gain an understanding of how adult children experienced providing social support to a parent with alcohol abuse problems or recovering from alcohol addiction. To conceptualize the study, Bowen's Family Systems Theory was used, which highlights the impact that alcohol abuse has on a family as a whole, and that it does not solely affect the individual who is addicted to alcohol. Participants were selected using convenience sampling. Adopting a qualitative approach, the researcher conducted individual semi-structured interviews in which participants were students between the ages of 25 and 38 years. The qualitative interviews were transcribed verbatim and transcriptions were analyzed using Interpretative Phenomenological Analysis (IPA).Ethical clearance was obtained from the University of the Western Cape Higher Degrees Committee. Informed consent for conducting this research study was obtained from the University of the Western Cape (UWC) and Kensington Treatment Centre (KTC) as well as from participants. The consent forms indicate that only the researcher and the researcher's supervisor have access to the data obtained. The researcher pledged confidentiality and adherence to ethical rules and regulations. The researcher ensured that participant anonymity was not compromised upon analysis of the data. The study found that parental alcohol abuse has negative effects on the support provider's well-being and their involvement in the parent-child relationship. Effects included feelings of anger and shame; giving in to peer pressure; engaging in substance use and risky sexual behaviours; distancing themselves emotionally; and keeping secrets. Furthermore, participants also experienced social alienation; emotional and sexual abuse; and a fragmentation of the parent-child relationship.

This study contends that time, narrative and justice cannot be separated from one another. One always demands that the other two also be considered. If we accept that law should be held accountable to a higher ethical standard, then law’s relationship with time and narrative is also important. Good law can only exist through a responsible and active engagement with this challenge. Unfortunately it is not in law’s interest to honour its responsibility, and the legal system as described by Niklas Luhmann is not interested in justice. Law’s only aims are to be legitimate and to ensure its own continued perpetuation. These aims are in threatened when law is required to appeal to norms outside of itself. Thus law has developed certain mechanisms in order to shirk this responsibility: It draws boundaries between itself and its environment; it removes its operations from human reality; it undermines human identity and agency (intention and causality) by reducing it in complexity and meaning; and finally it protects itself through building up its own unreal and false complexity. Law is able to do this by turning its back on its relationship with time (and by extension, narrative). Time is stripped of duration and reduced to a succession of presents. This has two effects: firstly human identity and agency becomes meaningless and secondly, moral or ethical judgment becomes impossible. By cutting the knot instead of trying to unravel it, law avoids its responsibility to be moral. One way of stepping up to the challenge of justice, time and law is through Ricoeur’s narrative time. Human beings and larger social entities all have narrative and temporal duration and location. It recognises that humans have an identity that can not be divorced from time and narrative. This structure also gives necessary context and meaning to actions, and allows us to make moral judgments. / Dissertation (LLM)--University of Pretoria, 2012. / Jurisprudence / unrestricted