Output-feedback online optimal control for a class of nonlinear systems

In this paper an output-feedback model-based reinforcement learning (MBRL) method for a class of second-order nonlinear systems is developed. The control technique uses exact model knowledge and integrates a dynamic state estimator within the model-based reinforcement learning framework to achieve output-feedback MBRL. Simulation results demonstrate the efficacy of the developed method

Use of Particle Swarm Optimization Algorithm to Reduce Drilling Costs by Finding Optimal Operational Parameters

Oil and gas companies have played a major role in the energy sector, and constantly try to develop technology to maximize their overall revenue. One of the more substantial feats was the developed equipment that allowed for horizontal wells. These horizontal sections allow much more oil to reach the wellbore due to the extended length into reservoir supplies. However, as the wells continue to get drilled farther, the cost of drilling the wells continue to rise. Now more than ever, there is an increased need for better drilling optimization techniques, which could potentially reduce these drilling costs and increase the overall profit. Many individuals have researched optimizing constant operational parameters; however, these constant variables lead to wasted time and money for the operators. This is because formation variables constantly change throughout the drilling process; therefore, the concept of dynamic variables allow drillers to alter the drilling parameters to better adjust for changes in the formation. The research presented herein, incorporates a particle swarm optimization (PSO) algorithm to optimizeoperational parameters, weight on bit (WOB), revolutions per minute (RPM) of the bit,bit pull depth, and bit combination, with the goal to decrease the overall drilling cost perfoot. A rate of penetration (ROP) model was incorporated with the PSO algorithm inorder to calculate the drilling time and the associated costs from the given parameters.This research could be applied in numerous ways including as an artificial intelligenceoptimizer in an existing drilling simulator, or directly integrated by drilling engineersduring the planning stage. Long term use for this algorithm is to be the foundation for anautonomous driller including being the real time optimal solver.Mechanical & Aerospace Engineerin

Online Observer-Based Inverse Reinforcement Learning

In this paper, a novel approach to the output-feedback inverse reinforcement learning (IRL) problem is developed by casting the IRL problem, for linear systems with quadratic cost functions, as a state estimation problem. Two observer-based techniques for IRL are developed, including a novel observer method that re-uses previous state estimates via history stacks. Theoretical guarantees for convergence and robustness are established under appropriate excitation conditions. Simulations demonstrate the performance of the developed observers and filters under noisy and noise-free measurements.Comment: 7 pages, 3 figure

Multiaddressable Photochromic Architectures: From Molecules to Materials

Multiaddressable architectures comprising light‐responsive photochromic molecules and different stimuli‐responsive components are appealing platforms for intelligent materials because of not only the potential diversity of components and corresponding properties, but also the functions resulting from their synergistic interactions. A variety of multiaddressable photochromic architectures are being designed to meet the demands of applications in different areas ranging from molecular machines to smart materials. This review highlights exciting recent advances in the field of multiaddressable systems that employ photoswitching molecules, specifically with regard to photo‐/chemical‐addressable, photo‐/pH‐addressable, photo‐/thermal‐addressable, photo‐/redox‐addressable, and multi‐photoaddressable architectures. Design concepts, crosstalk between different components, and photoswitch integration in these multiaddressable systems are discussed

Studying Underlying Characteristics of Computing and Engineering Student Success (SUCCESS) Survey

This survey was developed to measure underlying factors that may influence student success including personality, community, grit, thriving, identity, mindset, motivation, perceptions of faculty caring, stress, gratitude, self-control, mindfulness, and belongingness. We measure these underlying factors because each engineering and computing student admitted to a university has clear potential for academic and personal success in their undergraduate curriculum based upon admissions criteria. However, while some thrive academically, others struggle in a variety of ways. In our NSF-funded project (1626287/1626185/1626148), we posit that some collection of characteristics—apparently not visible on their admission applications and perhaps not related to their talent or intelligence—is an important piece of the student performance puzzle. We developed a survey to measure various non-cognitive and affective factors that we believe are important for student achievement, academically, personally, and professionally. These non-cognitive and affective factors are representative of multifaceted aspects of undergraduate student success in prior literature. Each of the constructs we chose had validity evidence from prior studies, some within an engineering population. An exploratory and confirmatory factor analysis have been conducted on the original list of items to develop this finalized survey (Scheidt et al., 2018). The survey takes approximately 30 minutes for students to complete. Scheidt, M., & Godwin, A., & Senkpeil, R. R., & Ge, J. S., & Chen, J., & Self, B. P., & Widmann, J. M., & Berger, E. J. (2018, June), Validity Evidence for the SUCCESS Survey: Measuring Non-Cognitive and Affective Traits of Engineering and Computing Students. Paper presented at 2018 ASEE Annual Conference & Exposition, Salt Lake City, Utah. https://peer.asee.org/3122

Morphology and dynamics of inflated subaqueous basaltic lava flows

International audienceDuring eruptions onto low slopes, basaltic Pahoehoe lava can form thin lobes that progressively coalesce and inflate to many times their original thickness, due to a steady injection of magma beneath brittle and viscoelastic layers of cooled lava that develop sufficient strength to retain the flow. Inflated lava flows forming tumuli and pressure ridges have been reported in different kinds of environments, such as at contemporary subaerial Hawaiian-type volcanoes in Hawaii, La Réunion and Iceland, in continental environments (states of Oregon, Idaho, Washington), and in the deep sea at Juan de Fuca Ridge, the Galapagos spreading center, and at the East Pacific Rise (this study). These lava have all undergone inflation processes, yet they display highly contrasting morphologies that correlate with their depositional environment, the most striking difference being the presence of water. Lava that have inflated in subaerial environments display inflation structures with morphologies that significantly differ from subaqueous lava emplaced in the deep sea, lakes, and rivers. Their height is 2-3 times smaller and their length being 10-15 times shorter. Based on heat diffusion equation, we demonstrate that more efficient cooling of a lava flow in water leads to the rapid development of thicker (by 25%) cooled layer at the flow surface, which has greater yield strength to counteract its internal hydrostatic pressure than in subaerial environments, thus limiting lava breakouts to form new lobes, hence promoting inflation. Buoyancy also increases the ability of a lava to inflate by 60%. Together, these differences can account for the observed variations in the thickness and extent of subaerial and subaqueous inflated lava flows

Self-testing for cancer: a community survey

<p>Abstract</p> <p>Background</p> <p>Cancer-related self-tests are currently available to buy in pharmacies or over the internet, including tests for faecal occult blood, PSA and haematuria. Self-tests have potential benefits (e.g. convenience) but there are also potential harms (e.g. delays in seeking treatment). The extent of cancer-related self-test use in the UK is not known. This study aimed to determine the prevalence of cancer-related self-test use.</p> <p>Methods</p> <p>Adults (n = 5,545) in the West Midlands were sent a questionnaire that collected socio-demographic information and data regarding previous and potential future use of 18 different self-tests. Prevalence rates were directly standardised to the England population. The postcode based Index of Multiple Deprivation 2004 was used as a proxy measure of deprivation.</p> <p>Results</p> <p>2,925 (54%) usable questionnaires were returned. 1.2% (95% CI 0.83% to 1.66%) of responders reported having used a cancer related self test kit and a further 36% reported that they would consider using one in the future. Logistic regression analyses suggest that increasing age, deprivation category and employment status were associated with cancer-related self-test kit use.</p> <p>Conclusion</p> <p>We conclude that one in 100 of the adult population have used a cancer-related self-test kit and over a third would consider using one in the future. Self-test kit use could alter perceptions of risk, cause psychological morbidity and impact on the demand for healthcare.</p

Making Well-being an Experiential Possibility: The Role of Sport

Whilst the relationship between active participation in sport and well-being has been widely acknowledged, less attention has been paid to actually understand this relationship from the perspective of the individual. Our paper draws upon phenomenological philosophy and the existential life-world view of well-being, in order to explore how the experience of sport can help facilitate possibilities for multiple kinds and levels of well-being. In doing so, our paper highlights the multiplicity of the dimensions of well-being, and offers examples of the different paths to well-being provided by sport, thus providing ways of describing well-being experiences within a sports context that are more complex than those offered by more traditional approaches to study in this area. Within this conceptual analysis we adopt a humanistic approach that considers the multiple ways well-being can be experienced through sport as a sense of dwelling, mobility or dwelling-mobility within the life-world dimensions of temporarily, spatiality, mood, embodiment, inter-subjectivity and identity