Magister Educationis (Adult Learning and Global Change) - MEd(AL) / This study was prompted by my observations and feedback from trainers and learners on an array of barriers to participation in learning which are experienced by learners participating in accredited adult learning programmes offered by a NGO in Cape Town. The aim of this research was to investigate these barriers using a Psychosocial Interaction Model by Merriam and Darkenwald (1982) and the Transition Theory by Schlossberg (1981). Participants in a Health and Welfare Seta (HWSETA) accredited training programme, which is a qualification in Ancillary Health Care level 1, who are community caregivers, were used as research participants. This research provided empirical evidence on barriers to participation in adult learning experienced by these learners and recommendations have been made based on the findings. A new theoretical insight that was generated as a result of this study is that of the interplay between internal and external barriers to participation in adult learning and other variables within the continuum of the Psychosocial Interaction Model as well as certain variables within the Transition Theory. This came as a result of broadening the investigation into barriers to participation in learning, using all variables across the whole spectrum of the Psychosocial Interaction Model, instead of only using the barriers factor.

Background: In treatment planning for intensity-modulated proton therapy (IMPT), we aim to deliver the prescribed dose to the target yet minimize the dose to adjacent healthy tissue. Mixed-integer programming (MIP) has been applied in radiation therapy to generate treatment plans. However, MIP has not been used effectively for IMPT treatment planning with dose-volume constraints. In this study, we incorporated dose-volume constraints in an MIP model to generate treatment plans for IMPT. Methods: We created a new MIP model for IMPT with dose volume constraints. Two groups of IMPT treatment plans were generated for each of three patients by using MIP models for a total of six plans: one plan was derived with the Limited-memory Broyden-Fletcher-Goldfarb-Shanno (L-BFGS) method while the other plan was derived with our MIP model with dose-volume constraints. We then compared these two plans by dose-volume histogram (DVH) indices to evaluate the performance of the new MIP model with dose-volume constraints. In addition, we developed a model to more efficiently find the best balance between tumor coverage and normal tissue protection. Results: The MIP model with dose-volume constraints generates IMPT treatment plans with comparable target dose coverage, target dose homogeneity, and the maximum dose to organs at risk (OARs) compared to treatment plans from the conventional quadratic programming method without any tedious trial-and-error process. Some notable reduction in the mean doses of OARs is observed. Conclusions: The treatment plans from our MIP model with dose-volume constraints can meetall dose-volume constraints for OARs and targets without any tedious trial-and-error process. This model has the potential to automatically generate IMPT plans with consistent plan quality among different treatment planners and across institutions and better protection for important parallel OARs in an effective way.

In this work, we present a new method for seismic waveform characterization, which is aimed at extracting detailed litho-stratigraphical information from seismic data. We attempt to estimate the lithological attributes from seismic data according to our parametric representation of stratigraphical horizons, where the parameter values provide us with a direct link to nature of lithological transitions. We test our method on a seismic dataset with a strong diagenetic transition (opal-A to opal-CT transition). Given some information from cutting samples of well, we use a percolation-based model to construct the elastic profile of lithological transitions. Our goal is to match parametric representation for the diagenetic transition in both real data and synthetic data given by these elastic profiles. This match may be interpreted as a well-seismic tie, which reveals lithological information about stratigraphical horizons. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate

Despite evidence to support physically active and passive leisure as significant contributors to well-being, for working mothers, fitting leisure into an already busy schedule can be challenging. The purpose of this study was to examine the influence of perceived time constraints and self-determination for physically active and passive leisure on conflict between these two leisure domains and the influence of this conflict on well-being among physically active working mothers. A total of 66 women who were physically active, worked at least 30 hours per week outside the home and had at least one child living in the home, participated in the study. At baseline, the participants completed a basic intake assessment in addition to validated questionnaires to measure time constraints and motivation for physically active and passive leisure. A two-week period of electronic experience sampling followed to evaluate leisure engagement. A final set of measures to evaluate conflict between physically active and passive leisure over the two weeks, and general well-being were completed at the end of the experience sampling period. Results indicated that despite relatively high levels of satisfaction with time available for both physically active and passive leisure, perceived time constraints were associated with increased goal conflict as are non-self-determined motivation for physically active leisure and self-determined motivation for passive leisure. Controlling for engagement in physically active and passive leisure, well-being is negatively influenced by goal conflict. Recommendations are provided regarding areas for additional research to further our understanding of the impact of opposing motivational orientations on goal conflict including the incorporation of Vallerand’s Dualistic Model of Passion (Vallerand et al., 2003). From a practical standpoint, the implications of the study results for interventions designed to address general well-being in middle class working mothers through targeting factors related to time constraints and goal conflict are discussed.

This dissertation develops a process improvement method for service operations based on the Theory of Constraints (TOC), a management philosophy that has been shown to be effective in manufacturing for decreasing WIP and improving throughput. While TOC has enjoyed much attention and success in the manufacturing arena, its application to services in general has been limited. The contribution to industry and knowledge is a method for improving global performance measures based on TOC principles. The method proposed in this dissertation will be tested using discrete event simulation based on the scenario of the service factory of airline turnaround operations. To evaluate the method, a simulation model of aircraft turn operations of a U.S. based carrier was made and validated using actual data from airline operations. The model was then adjusted to reflect an application of the Theory of Constraints for determining how to deploy the scarce resource of ramp workers. The results indicate that, given slight modifications to TOC terminology and the development of a method for constraint identification, the Theory of Constraints can be applied with success to services. Bottlenecks in services must be defined as those processes for which the process rates and amount of work remaining are such that completing the process will not be possible without an increase in the process rate. The bottleneck ratio is used to determine to what degree a process is a constraint. Simulation results also suggest that redefining performance measures to reflect a global business perspective of reducing costs related to specific flights versus the operational local optimum approach of turning all aircraft quickly results in significant savings to the company. Savings to the annual operating costs of the airline were simulated to equal 30% of possible current expenses for misconnecting passengers with a modest increase in utilization of the workers through a more efficient heuristic of deploying them to the highest priority tasks. This dissertation contributes to the literature on service operations by describing a dynamic, adaptive dispatch approach to manage service factory operations similar to airline turnaround operations using the management philosophy of the Theory of Constraints.

Design constraints is the first topic new interaction designers learn about intheir studies. These are supposed to be the properties of a design that limitsuser’s actions. This thesis aims to explore these constraints in depth tounderstand if there is more to learn about them when placed in a new setting,such as games. This knowledge could then be used to create better player oruser experience. To discover this, a detailed study of two escape rooms wasconducted and analyzed.The investigation showed that there is more to design constraints thanpreviously mentioned by theorists, especially when context changes, and thatdesign constraints should instead be interaction opportunities. Instead ofonly seeing constraints as limiting actions, they should become the clues forpossible interactions.

Cette thèse est composée de trois chapitres. Le premier chapitre, "Bertrand-Edgeworth Competition with Substantial Product Differentiation", étudie le comportement d'un duopole lorsque les deux entreprises sont caractérisées par des contraintes de capacité et produisent un bien différencié à la Hotelling. En limitant l'analyse au cas d'un degré élevé de différentiation du produit, je démontre l'existence d'au moins un équilibre en stratégie pure pour tous les niveaux de capacités. Le deuxième chapitre, "Monopoly Pricing with Dual Capacity Constraints" analyse un monopole qui est contraint par deux types de contraintes de capacité: un sur la quantité produite, l'autre sur le nombre des consommateurs. Je démontre que les prix optimaux choisis par les entreprises en court terme ne sont pas monotones dans le niveau des contraintes de capacité. En outre, le bien-être agrégé des consommateurs peut décroître si une des contraintes de capacité est augmentée. Le troisième chapitre, "Competition with Dual Capacity Constraints", étend l'analyse du deuxième chapitre au cas du duopole symétrique dans lequel les deux entreprises font face aux mêmes niveaux de capacité. Je démontre l'existence de conditions sous lesquelles la non-monotonicité des prix et du bien-être des consommateurs observée dans le 2ème chapitre est également présente dans le cas du duopole. Certains équilibres donnent naissance à des prix de duopole égaux au prix de monopole. En outre, les entreprises peuvent choisir des prix d'équilibre identiques sur les deux marchés malgré leur pouvoir de discrimination des prix. / This Ph.D. thesis is composed of three chapters. Since Kreps and Scheinkman's seminal article (1983) a large number of papers have analyzed capacity constraints' potential to relax price competition. However, the majority of the ensuing literature has assumed that products are either perfect or very close substitutes. Therefore very little is known about the interaction between capacity constraints and local monopoly power. The aim of the present paper is to shed light on this question using a standard Hotelling setup. The high level of product dierentiation results in a variety of equilibrium firm behavior and it generates at least one pure-strategy equilibrium for any capacity level. The second chapter, "Bertrand-Edgeworth Competition with Substantial Product Differentiation", studies the price-setting behavior of a monopoly facing two capacity constraints: one on the number of consumers it can serve, the other on the total amount of products it can sell. Facing two consumer groups that difer in their demands and the distribution of their willingness-to-pay, the monopoly's optimal non-linear pricing strategy consists of offering one or two price-quantity bundles. The characterization of the firm's optimal pricing as a function of its two capacities reveals a rich structure that also gives rise to some surprising results. In particular, I show that prices are non-monotonic in capacity levels. Moreover, there always exists a range of parameters in which weakening one of the capacity constraints decreases consumer surplus. In the long run, when the firms can choose how much capacity to build, prices and consumer surplus are monotonic in capacity costs. The third chapter, "Competition with Dual Capacity Constraints", studies duopoly pricing under dual capacity constraints, limiting both the total quantity and the number of consumers served. It extends both the analysis of monopoly pricing with dual capacity constraints and the symmetric models of Bertrand-Edgeworth competition with a singular capacity. By isolating parameter regions where a symmetric pure-strategy equilibrium exists, I nd that several types of equilibria are possible, depending on the model's specications. For some of them, duopoly prices are identical to monopoly prices. Equilibrium prices are non-monotonic in capacity levels if consumers' valuations are suciently heterogeneous. Moreover, I show that despite their ability to price discriminate, competition may lead firms to charge identical prices across markets.

This study was conceived as an attempt to determine .and analyze factors deterring participation in continuing professional education among social workers in environments where continuing education for relicensure is mandatory and voluntary. The specific research design implemented to complete this study was the ex-post facto descriptive design. The sample included 106 social workers randomly selected in the state of Texas where continuing education is mandatory and 94 social workers in the state of Louisiana where continuing education is voluntary. The instrument used was the Deterrent to Participation Scale developed by Scanlan (1983) and a demographic inventory. Scanlan (1983) earlier identified six factors deterring participation in continuing professional education: Disengagement, Lack of Quality, Family Constraints, Cost, Lack of Benefit, and Work Constraints. The study concluded that social workers in both states considered work constraint as a major factor deterring participation in continuing professional education. Also the factors of cost and lack of quality were also considered as crucial barriers in their efforts to participate in continuing professional education. The Wilks' multivariate test of significance of the means and univariate F tests at alpha level p < .05 revealed differences in the combined mean scores of social workers in both states when the variables of age, marital status, and position held were tested. In comparing the ranking of the six factors deterring participation in continuing professional education, a Spearman rank correlation coefficient revealed respondents in both states rank the six factors in the same order. The findings were congruent with earlier studies of barriers to participation in continuing education among professionals. The researcher recommended a study which would include a larger number of social workers and a longitudinal study to measure changes in barriers to participation in continuing professional education.

Creativity plays an important part in design and problem-solving. While the role of play has enjoyed a great deal of attention in the study of both creativity and problem-solving alike, the overlap between games and the creative problem-solving process has not enjoyed much scholarly attention. This dissertation therefore focuses on exploring the overlap between games and the creative problem-solving process. This exploration seeks to enhance the manner in which the role and function of gameplay within the creative problem-solving process is understood. This study is approached from the viewpoint of a thorough literature review and synthesises insights from design discourse, creativity studies and game design literature. Firstly, this study demonstrates the systemic similarities between games and creative problems. These similarities prove that both systems are capable of generating or allowing the emergence of gameplay. The second aspect focused on is the manner in which gameplay emerges from creative problem-solving and the value that it holds for that process. The third aspect focused on is the role and function of rules in both games and problem-solving in eliciting gameplay. These explorations culminate in a rudimentary framework that describes the manner in which the rules and limitations in a creative problem become established in order to allow gameplay to emerge. Lastly, the paper explores the psychological factors inherent in eliciting gameplay from a creative problem in the form of adopting a lusory attitude. The study ultimately demonstrates the crucial role of gameplay in creative problem-solving and the aspects that influence its emergence. / Dissertation (MA)--University of Pretoria, 2017. / Visual Arts / MA / Unrestricted

This study used action research to study the implementation of Critical Chain methodology in a multi-project environment. It used a medium sized company, which is an original equipment manufacturer, but due to the complexity of the equipment each is executed as a project. This creates a multi-project environment.The object of the research was to find the contributing and inhibiting factors to CC implementation. It further sought to discover improvements in business performance due to CC methodology.The study found resistance to change prevented CC implementation. The resistance to change was supported by incorrect application of CC principles and a false sense that CC is contributing to the business. On business performance improvements it was found that order intake improvements of thirty seven per cent year on year and reduction in lead time of projects due to implementation of CC principles. The latter also opened new markets which strategically benefitted the company. / Dissertation (MBA)--University of Pretoria, 2012. / Gordon Institute of Business Science (GIBS) / unrestricted