Optimization-Based Control Methodologies with Applications to Autonomous Vehicle

This thesis includes two main parts. In the first part, the main contribution is to develop nonsingular rigid-body attitude control laws using a convex formulation, and implement them in an experimental set up. The attitude recovery problem is first parameterized in terms of quaternions, and then two polynomial controllers using an SoS Lyapunov function and an SoS density function are developed. A quaternion-based polynomial controller using backstepping is also designed to make the closed-loop system asymptotically stable. Moreover, the proposed quaternion-based controllers are implemented in a Quanser helicopter, and compared to the polynomial controllers and a PID controller experimentally. The main contribution of the second part of this thesis is to analytically solve the Hamilton-Jacobi-Bellman equation for a class of third order nonlinear optimal control problems for which the dynamics are affine and the cost is quadratic in the input. One special advantage of this work is that the solution is directly obtained for the control input without the computation of a value function first. The value function can however also be obtained based on the control input. Furthermore, a Lyapunov function can be constructed for a subclass of optimal control problems, yielding a proof certificate for stability. Using the proposed methodology, experimental results of a path following problem implemented in a Wheeled Mobile Robot (WMR) are then presented to verify the effectiveness of the proposed methodology

Mother’s health after baby’s birth: does delivery method matter? : Does the delivery method matter?

The dramatic increase in the utilization of caesarean section has raised concerns on its impact on public expenditure and health. While the financial costs associated with this surgical procedure are well recognized, less is known on the intangible health costs borne by mothers and their families. We contribute to the debate by investigating the effect of unplanned caesarean deliveries on mothers’ mental health in the first nine months after the delivery. Differently from previous studies, we account for the unobserved heterogeneity due to the fact that mothers who give birth through an unplanned caesarean delivery may be different than mothers who give birth with a natural delivery. Identification is achieved exploiting exogenous variation in the position of the baby in the womb at the time of delivery while controlling for hospital unobserved factors. We find that mothers having an unplanned caesarean section are at higher risk of developing postnatal depression and this result is robust to alternative specifications

Why women do not adopt upright positions during labour and birth: an exploratory study

The position in which a woman births her baby is considered to be influenced by her social environment. The position adopted by a woman in labour has not only physiological stimuli but socio-cultural ones as well. Throughout the twentieth century women have been encouraged to remain in bed during labour and for the birth, which can be viewed as a position more convenient for the accoucheur, as this enabled easier access to undertake continuous fetal monitoring, intravenous therapy, vaginal examinations and to administer analgesia. A review of history however suggests today's birth postures were decreed and adopted on the basis of custom and convenience rather than physiological and anatomical indications and scientific data. There has been no study to examine the social context of women's choice of birth position or the influence of birth setting. This study was undertaken to explore what concerns, principles and environmental factors guide women in their choices regarding birth positions. The study used qualitative methods of data collection and employed induction rather than deduction in the analysis. Clarification of these factors may influence the future provision of care by midwives, in addition to highlighting factors which may enhance maternal satisfaction. A grounded theory approach was utilised in this study by means of antenatal and postnatal interviews in two different hospital settings. Several factors that influenced women's choice of birth position were identified, some of which were interrelated. These included physicial and social environment, disciplinary power present in the medical system and related technology. The midwife and her support are also important factors affecting women's choice of birth position. A decision making typology that can be utilised by midwives to enhance their practice and assist women in their choice of birth position had been developed from this study

Why women do not adopt upright positions during labour and birth : an exploratory study

The position in which a woman births her baby is considered to be influenced by her social environment. The position adopted by a woman in labour has not only physiological stimuli but socio-cultural ones as well. Throughout the twentieth century women have been encouraged to remain in bed during labour and for the birth, which can be viewed as a position more convenient for the accoucheur, as this enabled easier access to undertake continuous fetal monitoring, intravenous therapy, vaginal examinations and to administer analgesia. A review of history however suggests today's birth postures were decreed and adopted on the basis of custom and convenience rather than physiological and anatomical indications and scientific data. There has been no study to examine the social context of women's choice of birth position or the influence of birth setting. This study was undertaken to explore what concerns, principles and environmental factors guide women in their choices regarding birth positions. The study used qualitative methods of data collection and employed induction rather than deduction in the analysis. Clarification of these factors may influence the future provision of care by midwives, in addition to highlighting factors which may enhance maternal satisfaction. A grounded theory approach was utilised in this study by means of antenatal and postnatal interviews in two different hospital settings. Several factors that influenced women's choice of birth position were identified, some of which were interrelated. These included physicial and social environment, disciplinary power present in the medical system and related technology. The midwife and her support are also important factors affecting women's choice of birth position. A decision making typology that can be utilised by midwives to enhance their practice and assist women in their choice of birth position had been developed from this study.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

An Empirical Investigation of Architectural Heritage Management Implications for Tourism: The Case of Portugal

The aims of this study are manifold. First, to investigate the potentials of architectural heritage in the context of tourism destination development, as well as examine public sector policies and make plans toward the preservation of these resources. Secondly, to appraise the outcome of preservation and its implications for tourism. The study is an effort to explore and understand the interrelationships between tourism and architectural heritage sites through tourist image and perception. For the purposes of this research, numerous heritage sites were sampled in Portugal. A mixed research method was utilized to gauge tourists’ image/perception of heritage resources, and impact (quantitative approach). A qualitative approach was utilized to assess the priority of tourists in their visits and public-sector policies toward heritage resource management and planning. The fuzzy logic method was used to assess the architectural value and the tourist and preservation potential of historical buildings in Porto/Aveiro. The contribution and implications of the study are also explained. The results revealed that architectural heritage resources have the most appeal to tourists. The study to date demonstrates the architectural value and tourist and preservation potential of the buildings observed via evaluation by fuzzy logic methods

An Empirical Investigation of Architectural Heritage Management Implications for Tourism: The Case of Portugal

The aims of this study are manifold. First, to investigate the potentials of architectural heritage in the context of tourism destination development, as well as examine public sector policies and make plans toward the preservation of these resources. Secondly, to appraise the outcome of preservation and its implications for tourism. The study is an effort to explore and understand the interrelationships between tourism and architectural heritage sites through tourist image and perception. For the purposes of this research, numerous heritage sites were sampled in Portugal. A mixed research method was utilized to gauge tourists’ image/perception of heritage resources, and impact (quantitative approach). A qualitative approach was utilized to assess the priority of tourists in their visits and public-sector policies toward heritage resource management and planning. The fuzzy logic method was used to assess the architectural value and the tourist and preservation potential of historical buildings in Porto/Aveiro. The contribution and implications of the study are also explained. The results revealed that architectural heritage resources have the most appeal to tourists. The study to date demonstrates the architectural value and tourist and preservation potential of the buildings observed via evaluation by fuzzy logic methods