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This thesis considers the optimisation of vehicle suspension systems via a reinforcement learning technique The aim is to assess the potential of learning automata to learn 'optimum' control of suspension systems, which contain some active element under electronic control, without recourse to system models. Control optimisation tasks on full-active and senu-active suspension systems are used for the feasibility assessment and subsequent development of the learning automata technique. The quarter-vehicle simulation model, with ideal full-active suspension actuation, provides a well-known environment for initial studies applying classical discrete learning automata to learn the controller gains of a linear state-feedback controller. Learning automata are shown to be capable of acquiring near optimal controllers without any explicit knowledge of the suspension environment. However, the methodology has to be developed to allow safe on-line application. A moderator is introduced to prevent excessive suspension deviations as a result of possible unstable control actions applied during learning. A hardware trial is successfully implemented on a test vehicle fitted with semi-active suspension, excited by a hydraulic road simulation rig. During these initial studies some inherent weaknesses of the discrete automata are noted A discrete action set provides insufficient coverage of a continuous controller space so optima may be overlooked. Subsequent methods to increase the resolution of search lead to a forced convergence and hence an increased likelihood of local optima location. Th1s motivates the development of a new formulation of learning automaton, the CARLA, which exhibits a continuous action space and a reinforcement generalisation. The new method is compared w1th discrete automata on vanous stochastic function optimisatwn case stui1es, demonstrating that the new functionality of CARLA overcomes many of the identified shortcomings of discrete automata. Furthermore, CARLA shows a potential capability to learn in non-stationary environments. Repeatmg the earlier suspension tasks with CARLA applied, including an on-line hardware study, further demonstrates a performance gain over discrete automata Finally, a complex multi-goal learning task is considered A dynamic roll-control strategy is formulated based on the senu-active suspension hardware of the test vehicle. The CARLA is applied to the free parameters of this strategy and is seen to successfully synthesise improved roll-control over passive suspension.

Approved for public release; distribution is unlimited / Both the number of hosts using Internet Protocol version 6 (IPv6), and the volume of IPv6 traffic, has increased exponentially since 2012.With this adoption, the IPv6 routed infrastructure becomes an increasingly important component of global critical infrastructure and network policy. Unfortunately, the tools and techniques used to perform active network topology discovery were designed for Internet Protocol version 4 (IPv4), leading to a potentially opaque view of the IPv6 Internet. In this thesis, we extend nascent work on stateless high-speed IPv4 active topology probing to develop a new IPv6 traceroute method Yelling At Random Routers Progressively version 6 (Yarrp6). Yarrp6 randomly permutes the set of IPv6 targets and hop counts to distribute load, thereby helping to avoid IPv6 response rate limiting. Further, we encode state in the IPv6 payload to permit Yarrp6 to both match responses with probes and use different probe transport protocols. Via active experimentation on the public IPv6 Internet, we compare the results obtained from Yarrp6 against the current state-of-the-art IPv6 topology mapping tool. We show that Yarrp6 can discover topology at more than an order of magnitude faster than previously possible. Finally, we conduct a study of the effect of transport layer protocol on forward Internet Protocol (IP) path inference to determine what protocol is best used for active IPv6 topology discovery. / Outstanding Thesis / Information Systems Technician First Class, United States Navy

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Background: The HIV/AIDS epidemic is continuing to impact negatively on the health of populations globally. The region most affected by this epidemic is sub-Saharan Africa, with two-thirds of people living with HIV/AIDS located in this region. In order to combat this epidemic, countries are putting up efforts to scale-up the provision of antiretrovirals to affected individuals. South Africa faces challenges similar to other sub-Saharan countries in the scaling-up of antiretrovirals, such as cost of drugs, inadequate laboratory infrastructure and the low and declining number of health professionals. Therefore, the contribution of private general practitioners as part of the overall strategy to combat the HIV/AIDS epidemic needs to be considered. However, the performance of antiretroviral programmes in the private sector are unknown and there is therefore a need to explore patient outcomes in antiretroviral programmes being run by general practitioners in the private sector. The findings of this study will add to understanding what the outcomes of ARV programmes by GPs in private practice could be in a public-private partnership. Aims: The main aim of the study was to evaluate patient outcomes in an antiretroviral programme in the setting of a solo private general practitioner. Methods: This was a cross-sectional study using retrospective data from March 2005 to February 2008. A total of 170 patient records from a private general practitioner’s rooms were examined. The data were analysed using the using the median, interquartile and proportions. The Chi square was used to test for association between baseline characteristics and patient outcomes in the univariate analysis. Results: The increase in median CD4 count was 242 cells/μl and 265 cells/μl at 6 months and 12 months respectively. The proportion of patients who achieved viral suppression at 6 months and 12 months was 75% and 73% respectively. Rate of loss to follow-up was 29% and 38% at 6 months and 12 months respectively, which was much higher than in other settings. Although there were no statistically significant associations established by the study, the patterns emerging from the study showed that the baseline characteristics that were a risk for poor virological outcomes during the period of the study were female gender, younger age group, higher WHO clinical staging, lower CD4 count and higher viral load. Baseline characteristics that were a risk for loss to follow-up during the period of the study were male gender, younger age group, higher WHO clinical staging, lower CD4 count and higher viral load. Conclusion: Patient outcomes in an antiretroviral programme in the setting of a solo private general practitioner are comparable with patient outcomes in antiretroviral programmes in public sector settings in terms of immunological and virological outcomes. However, the lost to follow-up rate was much higher than in public sector settings.