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This research formulates and implements a novel closed-loop optimal control system that drives a train between two stations in an optimal time, energy efficient, or mixed objective manner. The optimal controller uses sensor feedback from the train and in real-time computes the most efficient control decision for the train to follow given knowledge of the track profile ahead of the train, speed restrictions and required arrival time windows. The control problem is solved both on an open track and while safely driving no closer than a fixed distance behind another locomotive. In contrast to other research in the field, this thesis achieves a real-time capable and embeddable closed-loop optimization with advanced modeling and numerical solving techniques with a non-linear optimal control problem. This controller is first formulated as a non-convex control problem and then converted to an advanced convex second-order cone problem with the intent of using a simple numerical solver, ensuring global optimality, and improving control robustness. Convex and non-convex numerical methods of solving the control problem are investigated and closed-loop performance results with a simulated vehicle are presented under realistic modeling conditions on advanced tracks both on desktop and embedded computer architectures. It is observed that the controller is capable of robust vehicle driving in cases both with and without modeling uncertainty. The benefits of pairing the optimal controller with a parameter estimator are demonstrated for cases where very large mismatches exists between the controller model and the simulated vehicle. Stopping performance is consistently within 25cm of target stations, and the worst case closed-loop optimization time was within 100ms for the computation of a 1000 point control horizon on an i7-6700 machine. / Thesis / Master of Applied Science (MASc) / This research formulates and implements a novel closed-loop optimal control system that drives a train between two stations in an optimal time, energy efficient, or mixed objective manner. It is deployed on a commuter vehicle and directly manages the motoring and braking systems. The optimal controller uses sensor feedback from the train and in real-time computes the most efficient control decision for the train to follow given knowledge of the track profile ahead of the train, speed restrictions and required arrival time windows. The final control implementation is capable of safe, high accuracy and optimal driving all while computing fast enough to reliably deploy on a rail vehicle.

A deep scientific understanding of complex physical systems, such as the atmosphere, can be achieved neither by direct measurements nor by numerical simulations alone. Data assimilation is a rigorous procedure to fuse information from a priori knowledge of the system state, the physical laws governing the evolution of the system, and real measurements, all with associated error statistics. Data assimilation produces best (a posteriori) estimates of model states and parameter values, and results in considerably improved computer simulations. The acquisition and use of observations in data assimilation raises several important scientific questions related to optimal sensor network design, quantification of data impact, pruning redundant data, and identifying the most beneficial additional observations. These questions originate in operational data assimilation practice, and have started to attract considerable interest in the recent past. This dissertation advances the state of knowledge in four dimensional variational (4D-Var) - data assimilation by developing, implementing, and validating a novel computational framework for estimating observation impact and for optimizing sensor networks. The framework builds on the powerful methodologies of second-order adjoint modeling and the 4D-Var sensitivity equations. Efficient computational approaches for quantifying the observation impact include matrix free linear algebra algorithms and low-rank approximations of the sensitivities to observations. The sensor network configuration problem is formulated as a meta-optimization problem. Best values for parameters such as sensor location are obtained by optimizing a performance criterion, subject to the constraint posed by the 4D-Var optimization. Tractable computational solutions to this "optimization-constrained" optimization problem are provided. The results of this work can be directly applied to the deployment of intelligent sensors and adaptive observations, as well as to reducing the operating costs of measuring networks, while preserving their ability to capture the essential features of the system under consideration. / Ph. D.

The present thesis employs ideas of set invariance and sliding modes in order to deal with different relevant problems control of nonlinear systems. Initially, it reviews the techniques of set invariance as well as the more relevant results about sliding modes control. Then the main methodologies used are presented: sliding mode reference conditioning, second order sliding modes and continuous approximation of sliding modes. Finally, the methodologies are applied to different problems in control theory and to a variety of biologically inspired applications. The contributions of the thesis are: The development of a method to coordinate dynamical systems with different dynamic properties by means of a sliding mode auxiliary loop shaping the references given to the systems as function of the local and global goals, the achievable performance of each system and the available information of each system. Design methods for second order sliding mode algorithms. The methods decouple the problem of stability analysis from that of finite-time convergence of the super-twisting sliding mode algorithm. A nonlinear change of coordinates and a time-scaling are used to provide simple, yet flexible design methods and stability proofs. Application of the method to the design of finite-time convergence estimators of bioprocess kinetic rates and specific biomass growth rate, from biomass measurements. Also the estimators are validated with experimental data. The proposal of a strategy to reduce the variability of a cell-to-cell communication signal in synthetic genetic circuits. The method uses set invariance and sliding mode ideas applied to gene expression networks to obtain a reduction in the variance of the communication signal. Experimental approaches available to modify the characteristics of the gene regulation function are described. / Vignoni, A. (2014). Invariance and Sliding Modes. Application to coordination of multi-agent systems, bioprocesses estimation, and control in living cells [Tesis doctoral]. Editorial Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/37743

The fast-paced growth in microelectromechanical systems (MEMS), microfluidic fabrication, porous media applications, biomedical assemblies, space propulsion, and vacuum technology demands accurate and practical transport equations for rarefied gas flows. It is well-known that in rarefied situations, due to strong deviations from the continuum regime, traditional fluid models such as Navier-Stokes-Fourier (NSF) fail. The shortcoming of continuum models is rooted in nonequilibrium behavior of gas particles in miniaturized and/or low-pressure devices, where the Knudsen number (Kn) is sufficiently large. Since kinetic solutions are computationally very expensive, there has been a great desire to develop macroscopic transport equations for dilute gas flows, and as a result, several sets of extended equations are proposed for gas flow in nonequilibrium states. However, applications of many of these extended equations are limited due to their instabilities and/or the absence of suitable boundary conditions. In this work, we concentrate on regularized 13-moment (R13) equations, which are a set of macroscopic transport equations for flows in the transition regime, i.e., Kn≤1. The R13 system provides a stable set of equations in Super-Burnett order, with a great potential to be a powerful CFD tool for rarefied flow simulations at moderate Knudsen numbers. The goal of this research is to implement the R13 equations for problems of practical interest in arbitrary geometries. This is done by transformation of the R13 equations and boundary conditions into general curvilinear coordinate systems. Next steps include adaptation of the transformed equations in order to solve some of the popular test cases, i.e., shear-driven, force-driven, and temperature-driven flows in both planar and curved flow passages. It is shown that inexpensive analytical solutions of the R13 equations for the considered problems are comparable to expensive numerical solutions of the Boltzmann equation. The new results present a wide range of linear and nonlinear rarefaction effects which alter the classical flow patterns both in the bulk and near boundary regions. Among these, multiple Knudsen boundary layers (mechanocaloric heat flows) and their influence on mass and energy transfer must be highlighted. Furthermore, the phenomenon of temperature dip and Knudsen paradox in Poiseuille flow; Onsager's reciprocity relation, two-way flow pattern, and thermomolecular pressure difference in simultaneous Poiseuille and transpiration flows are described theoretically. Through comparisons it is shown that for Knudsen numbers up to 0.5 the compact R13 solutions exhibit a good agreement with expensive solutions of the Boltzmann equation.

Like death, the defining human reality underlying our relationships and views of life's meaning, the experiences and activities of undertakers, remains an uncommon subject for psychological research. Existential anxiety roots a society-wide denial of the fundamental nature of death. which necessitates the development of institutions to take responsibility for the dying and dead. As the image and service of the stigmatised funeral industry improves, society's experience of death should become more meaningful. The overview of the research into these topics noted the need for further studies. Within a holistic, ecosystemic epistemology, this study adopted a qualitative approach and case study method, which provided descriptions of the ecology, contexts, and relationships characteristic .of the undertaker's vocation by focussing on patterned expressions of views and attitudes. The aim was to gain insight into the undertaker's experience of the many faces of death, with a genuine interest and deep respect for their world. / Psychology / M.A. (Clinical Psychology)

Text in Afrikaans / Die objek van studie in hierdie proefskrif is ietwat ongewoon. Die studie is outobiografies en is gegrond op die aanname dat daar tussen die psigoterapeut, sy geskiedenis, die wetenskap (etnografie en tweede-orde kubernetika) en die klient(e) 'n unieke patroonverband bestaan. Die psigoterapeut in die platteland het weens afstand of finansies nie altyd die voorreg om supervisie van 'n eksterne supervisor te ontvang nie. In so 'n situasie kan selfsupervisie, deurdat dit 'n proses van selfontdekking is, 'n belangrike rol in die psigoterapeut se selfontwikkeling speel. Selfsupervisie plaas die klem op die psigoterapeut as persoon en as terapeut; oor wie hy is, waar hy vandaan kom en waarheen hy binne die psigoterapeutiese proses op pad is. Vir enige psigoterapeut is dit belangrik om na 'n hoer vlak van psigoterapie te streef. Hierdie strewe impliseer 'n proses van selfondersoek, delwing, selfevaluasie en disseksie. Hierdie proses is aan die hand van dagboekinskrywings gedoen, waar die psigoterapeut sy daaglikse ervarings en gebeurtenisse vanuit die verlede interpreteer het. Dit plaas die psigoterapeut as hoofspeler, met sy familiegeskiedenis en huidige interpersoonlike opset as inherente deel van sy mondering, op die voorgrond. In hierdie proses word die psigoterapeut sentraal geplaas met die klem op eie verantwoordelikheid met betrekking tot die proses van selfsupervisie. Die probleme wat deur hierdie persoonlik gekleurde, wetenskaplike studie aangespreek word, is probleme wat die psigoterapeut deur middel van sy selfsupervisie ge1dentifiseer het. So 'n selfondersoek lei tot 'n diepere selfkennis wat die psigoterapeut tot voordeel van homself, sy gesinsisteem en klientsisteem kan gebruik. Hierdie studie is 'n poging om 'n nuwe wyse van navorsing te identifiseer. Dit is omvattend en lei tot persoonlike vervulling asook diepere selfkennis en is 'n man waardeur ander psigoterapeute ook hulself en hul werelde kan ontdek. Dit is 'n stadige en pynlike proses. Hoofstukke 1 tot 4 is die teoretiese, wetenskaplike beredenering van die studie en hoofstukke 5 tot 12 is 'n uitbeelding van die geskiedenis van die psigoterapeut. Hoofstuk 13 plaas selfsupervisie as selfevalueringsmetode binne die psigoterapeutiese beroep. / The object of this study somewhat unusual. The study is an autobiography based on the assumption that there exists an unique patterned connection between the psychotherapist, his history, science (ethnography and second-order cybernetics), and his clients. Due to distance or financial problems, a rural psychotherapist cannot experience the privilege of supervision with an external supervisor. In such a situation selfsupervision could play an important role in the self-development, because it includes a search of self that will lead to more effectiveness in psychotherapy. Self-supervision focuses on the psychotherapist as a person and therapist, who he is, where he comes from, and in what direction he, as a psychotherapist, is developing within the psychotherapeutic process. It is important to any psychotherapist to strive towards a higher level of psychotherapy. This implies a process of selfinvestigation, dissection and self-evaluation. This process was conducted by means of diary entries in which the psychotherapist interpreted his daily experiences and events in terms of his past. This places the psychotherapist, with his family history and current interpersonal situation, as intrinsic parts of himself, in the foreground. In this process the psychotherapist takes centre stage with emphasis on his responsibility concerning the process of self-supervision. The problems addressed by this personally coloured, scientific study, are problems that the psychotherapist identified through the process of self-supervision and introspection. Such introspection leads to a deeper personal knowledge which the psychotherapist can use to his own benefit but also to the benefit of his family and client system. This study is an attempt to identify a new way of research. It is comprehensive and leads to personal fulfilment and deeper self-knowledge and is also a method by which other psychotherapists could discover themselves and their worlds. It is a slow and painful process. Chapters 1 to 4 comprise of the theoretical rationale of the study and chapters 5 to 12 depict the history of the psychotherapist. Chapter 13 situates self-supervision as a method of self-evaluation in the profession of psychotherapy. / Psychology / D. Litt. et Phil.

D. Admin. (Public Administration)

Text in Afrikaans / In die studie word die ontwikkelingspad van 'n Newtoniaanse benadering na 'n ekosistemiese benadering in die denke van die navorser en lewering van pleegsorgdienste deur die maatskaplike werker/navorser, beskryf. In die beskrywing is gefokus op drie beginsels elk van die Newtoniaanse - en die ekosistemiese benaderings. Die gekose beginsels is met 'n gevallestudie geillustreer. Aan die ha d van die beginsels van die ekosistemiese benadering word 'n konsepsuele raamwerk gebied waardeur die outonomie van mense en sisteme in stand gehou en gebruik kan word. Volgens tweede orde kubernetika, is die studie die konstruksie van die navorser. Pleegsorg is 'n komplekse alternatiewe versorgingsposisie vir 'n kind en die lewering van begeleidingsdienste stel besondere eise aan die professionele persone betrokke. Hierdie studie suggereer dat pleegsorgdienste wat aan die hand van die ekosistemiese benadering gelewer word, 'n konstruksie van gedeelde verantwoordelikheid tussen al die betrokke partye voorstel. / Social Work / M. A. (Social Science: Mental Health)