Time series prediction using supervised learning and tools from chaos theory

A thesis submitted to the Faculty of Science and Computing, University of Luton, in partial fulfilment of the requirements for the degree of Doctor of PhilosophyIn this work methods for performing time series prediction on complex real world time series are examined. In particular series exhibiting non-linear or chaotic behaviour are selected for analysis. A range of methodologies based on Takens' embedding theorem are considered and compared with more conventional methods. A novel combination of methods for determining the optimal embedding parameters are employed and tried out with multivariate financial time series data and with a complex series derived from an experiment in biotechnology. The results show that this combination of techniques provide accurate results while improving dramatically the time required to produce predictions and analyses, and eliminating a range of parameters that had hitherto been fixed empirically. The architecture and methodology of the prediction software developed is described along with design decisions and their justification. Sensitivity analyses are employed to justify the use of this combination of methods, and comparisons are made with more conventional predictive techniques and trivial predictors showing the superiority of the results generated by the work detailed in this thesis

Magnetic resonance studies of point defects in single crystal diamond

The results from EPR studies of CVD diamond which was intentionally silicon doped with isotopes in natural abundance or isotopically enriched are reported. The observation of hyperfine satellites arising due to the presence of 29Si has provided definitive evidence for the involvement of silicon in two EPR centres in diamond which were previously suspected to involve silicon: KUL1 and KUL3. KUL1 is unambiguously identified as the neutral silicon split vacancy defect (V-Si-V)0, whilst KUL3 is shown to be (V-Si-V)0 decorated with a hydrogen atom. Data have also revealed that (V-Si-V)0 is preferentially oriented in samples grown on {110} substrates. The negative nitrogen-vacancy centre (NV‑) has been investigated. Published parameters for the nitrogen hyperfine interaction produce an unsatisfactory fit to the experimental spectra and hence these parameters are redetermined. Optically-excited EPR has been used to estimate the degree of spin polarisation of the NV-ground state and the increase in signal intensity with illumination has permitted the interaction between the unpaired electron and neighbouring 13C atoms to be studied. Two sets of 13C hyperfine satellites have been identified, which account for ~100% of the unpaired electron probability density. Despite the predictions that the neutral charge state of NV should have an S = ½ ground state, this charge state has not previously been detected by EPR. Optically excited EPR measurements reveal a trigonal nitrogen containing defect in diamond with an excited state populated via optical excitation. Analysis of the spin-Hamiltonian parameters and the wavelength dependence of the optical excitation leads to assignment of this state to the 4A2 excited state of NV0

Teaching systems and robotics in a four-week summer short course

This paper describes a four-week summer short-course designed to introduce students with limited hands-on technical experience to the low-level details of embedded systems and robotics. Students start the course using a Raspberry Pi 3 to learn the basics of Linux and programming, and end the course by competing in a capture-the-flag type competition with the web-configurable GPS-guided autonomous robots they designed and tested in the course. Throughout the course, students are introduced to programming languages including Python and PHP, advanced programming concepts such as using sockets for inter-process communication, data interchange formats such as JSON, basic API development, system concepts such as I2C and UART serial interfaces, PWM motor control, and sensor fusion to improve robotic navigation and localization. This course was offered to students for the first time in the summer of 2016, and though formal feedback collection was limited, informal feedback indicated that students found the course to be challenging, engaging, and beneficial to their overall understanding of engineering. The paper walks the reader through the background of this course. It then discusses the weekly lesson plans, supplemental material provided to the students, and our general strategy for teaching the course\u27s programming and system design concepts in such an accelerated time frame. Finally, the paper discusses the student and instructor reactions to the course, lessons learned, and suggestions for future offerings. The material developed for this course will be posted online so that other educators may use it in their teaching

Toward an open cloud standard

Today's cloud ecosystem features several increasingly divergent management interfaces. Numerous bridging efforts attempt to ameliorate the resulting vendor lock-in for customers. However, as the number of providers continues to grow, the drawback of this approach becomes apparent: the need to maintain adapter implementations. The Open Cloud Computing Interface builds on the fundamentals of modern Web-based services to define a standardized interface for cloud environments while enabling service providers to differentiate their service offerings at the same time

Magnetic resonance studies of point defects in single crystal diamond

The results from EPR studies of CVD diamond which was intentionally silicon doped with isotopes in natural abundance or isotopically enriched are reported. The observation of hyperfine satellites arising due to the presence of 29Si has provided definitive evidence for the involvement of silicon in two EPR centres in diamond which were previously suspected to involve silicon: KUL1 and KUL3. KUL1 is unambiguously identified as the neutral silicon split vacancy defect (V-Si-V)0, whilst KUL3 is shown to be (V-Si-V)0 decorated with a hydrogen atom. Data have also revealed that (V-Si-V)0 is preferentially oriented in samples grown on {110} substrates. The negative nitrogen-vacancy centre (NV‑) has been investigated. Published parameters for the nitrogen hyperfine interaction produce an unsatisfactory fit to the experimental spectra and hence these parameters are redetermined. Optically-excited EPR has been used to estimate the degree of spin polarisation of the NV-ground state and the increase in signal intensity with illumination has permitted the interaction between the unpaired electron and neighbouring 13C atoms to be studied. Two sets of 13C hyperfine satellites have been identified, which account for ~100% of the unpaired electron probability density. Despite the predictions that the neutral charge state of NV should have an S = ½ ground state, this charge state has not previously been detected by EPR. Optically excited EPR measurements reveal a trigonal nitrogen containing defect in diamond with an excited state populated via optical excitation. Analysis of the spin-Hamiltonian parameters and the wavelength dependence of the optical excitation leads to assignment of this state to the 4A2 excited state of NV0.EThOS - Electronic Theses Online ServiceEngineering and Physical Sciences Research Council (Great Britain) (EPSRC)Diamond Trading Company Research Centre (Maidenhead) (DTCRC)GBUnited Kingdo

The control of magma crystallinity on the fluctuations in gas composition at open vent basaltic volcanoes

Basaltic open vent volcanoes are major global sources of volcanic gases. Many of these volcanoes outgas via intermittent Strombolian-type explosions separated by periods of passive degassing. The gas emitted during the explosions has high molar CO2/SO2 and SO2/HCl ratios, while during the passive degassing these ratios are lower. We present new laboratory experiments in a model volcanic conduit, which suggest that these differences in gas geochemistry are a consequence of gas migration through crystal-rich magma. We show that gas may flow along channels through the particle-laden liquid and, at a critical depth, the gas may displace an overlying crystal-rich plug en masse, producing a growing slug of gas. Owing to the friction on the walls of the conduit, this plug becomes progressively sheared and weakened until gas enriched in the least soluble volatiles breaks through, causing an explosion at the surface. When the gas slug bursts, liquid is drawn up in its wake, which exsolves the more soluble volatile components, which then vent passively at the surface until the next explosive slug-bursting event

The effects of highly active antiretroviral therapy on survival and CD4 cell percentage in HIV-infected children in Kinshasa, Democratic Republic of Congo

In HIV-infected children, the effects of highly active antiretroviral therapy (HAART) on survival and CD4 responses are understood incompletely. As most pediatric HIV infections occur in lower-income countries, our objective was to provide the first estimates of these effects among children in a resource-deprived setting. Observational data from HAART-naive children enrolled into an HIV care and treatment program in Kinshasa, Democratic Republic of Congo between December 2004 and May 2010 were analyzed. Marginal structural models were used to quantify the effects of HAART on survival and CD4 percentage while accounting for time-dependent confounders affected by prior exposure to HAART. At the start of follow-up, the median age of the 790 children was 5.9 years; 528 (67%) had advanced or severe immunodeficiency and 405 (51%) were in HIV clinical stage 3 or 4. The children were observed for a median of 31 months and contributed 2,090 person-years. Eighty children (10%) died, 619 (78%) initiated HAART, six (1%) transferred care to another facility, and 76 (10%) were lost to follow-up. The mortality rate was 3.2 per 100 person-years (95% CI: 2.4, 4.2) during HAART and 6.0 (95% CI: 4.1, 8.6) during receipt of primary HIV care only. The mortality hazard ratio comparing HAART to no HAART was 0.25 (95% CI: 0.06, 0.95). Compared to no HAART, the estimated absolute rise in CD4 percentage was 6.8% (95% CI: 4.7%, 8.9%) after six months of HAART, 8.6% (95% CI: 7.0%, 10.2%) after 12 months, and 20.5% (95% CI: 16.1%, 24.9%) after 60 months. HAART-mediated CD4 percentage gains were slowest but greatest among children who had a baseline CD4 percentage <15. The cumulative incidence of recovery to not significant WHO age-specific immunodeficiency was lower if HAART was initiated when immunodeficiency was severe rather than mild or advanced. HAART reduced the hazard of mortality and increased CD4 percentages among HIV-infected children in a resource-deprived setting to a similar degree as previously noted for children in the United States. The more gradual and protracted immunological recovery observed in children with lower baseline CD4 percentages supports earlier initiation of pediatric HAART