Fine-grained traffic state estimation and visualisation

Tools for visualising the current traffic state are used by local authorities for strategic monitoring of the traffic network and by everyday users for planning their journey. Popular visualisations include those provided by Google Maps and by Inrix. Both employ a traffic lights colour-coding system, where roads on a map are coloured green if traffic is flowing normally and red or black if there is congestion. New sensor technology, especially from wireless sources, is allowing resolution down to lane level. A case study is reported in which a traffic micro-simulation test bed is used to generate high-resolution estimates. An interactive visualisation of the fine-grained traffic state is presented. The visualisation is demonstrated using Google Earth and affords the user a detailed three-dimensional view of the traffic state down to lane level in real time

Wind turbine condition assessment through power curve copula modeling

Power curves constructed from wind speed and active power output measurements provide an established method of analyzing wind turbine performance. In this paper it is proposed that operational data from wind turbines are used to estimate bivariate probability distribution functions representing the power curve of existing turbines so that deviations from expected behavior can be detected. Owing to the complex form of dependency between active power and wind speed, which no classical parameterized distribution can approximate, the application of empirical copulas is proposed; the statistical theory of copulas allows the distribution form of marginal distributions of wind speed and power to be expressed separately from information about the dependency between them. Copula analysis is discussed in terms of its likely usefulness in wind turbine condition monitoring, particularly in early recognition of incipient faults such as blade degradation, yaw and pitch errors

Digital filter structures from classical analogue networks

Imperial Users onl

Optimal and Robust Quantum Metrology Using Interaction-Based Readouts

Useful quantum metrology requires nonclassical states with a high particle number and (close to) the optimal exploitation of the state's quantum correlations. Unfortunately, the single-particle detection resolution demanded by conventional protocols, such as spin squeezing via one-axis twisting, places severe limits on the particle number. Additionally, the challenge of finding optimal measurements (that saturate the quantum Cram{\'e}r-Rao bound) for an arbitrary nonclassical state limits most metrological protocols to only moderate levels of quantum enhancement. "Interaction-based readout" protocols have been shown to allow optimal interferometry \emph{or} to provide robustness against detection noise at the expense of optimality. In this Letter, we prove that one has great flexibility in constructing an optimal protocol, thereby allowing it to also be robust to detection noise. This requires the full probability distribution of outcomes in an optimal measurement basis, which is typically easily accessible and can be determined from specific criteria we provide. Additionally, we quantify the robustness of several classes of interaction-based readouts under realistic experimental constraints. We determine that optimal \emph{and} robust quantum metrology is achievable in current spin-squeezing experiments.Comment: 7 pages, 3 figure

Lyophilisation of lentiviral pseudotypes for the development and distribution of virus neutralisation assay kits for rabies, Marburg and influenza viruses

Purpose: Some conventional serological assays can accurately quantify neutralising antibody responses raised against epitopes on virus glycoproteins, enabling mass vaccine evaluation and serosurveillance studies to take place. However, these assays often necessitate the handling of wild-type virus in expensive high biosafety laboratories, which restricts the scope of their application, particularly in resource-deprived areas. A solution to this issue is the use of lentiviral pseudotype viruses (PVs)—chimeric, replication-deficient virions that imitate the binding and entry mechanisms of their wild-type equivalents. Pseudotype virus neutralisation assays (PVNAs) bypass high biosafety requirements and yield comparable results to established assays. This study explores the potential for using lyophilisation of pseudotypes as a cost-effective, alternative means for production, distribution and storage of a PVNAbased diagnostic kit. Methods & Materials: Rabies, Marburg and H5 subtype Influenza virus pseudotypes were each suspended in cryoprotectant solutions of various molarities and subjected to freeze-drying before incubation at a variety of temperatures, humidities and time periods. Samples were then employed in antibody neutralisation assays using specific sera. Results: High levels of PV titre were retained post-lyophilisation, with acceptable levels of virus activity maintained even after medium-term storage in tropical conditions. Also, the performance of PVs in neutralisation assays was not affected by the lyophilisation process. Conclusion: These results confirm the viability of a freeze-dried PVNA-based diagnostic kit, which could considerably facilitate in-field serology for a number of clinically important viruses

THE EFFECTS OF STREPTOZOTOCIN-INDUCED DIABETES ON RESPONSES TO OPIATES AND OTHER CENTRALLY-ACTING PHARMACOLOGIC AGENTS

Diabetes mellitus affects millions of people. Although diabetics can lead relatively normal lives, all treatments for the disease are symptomatic and not curative. The purpose of this investigation was to determine whether the sensitivity to opiates and other selected centrally-acting drugs in animals is altered by streptozotocin (STZ)-induced diabetes. A second objective was to determine which aspect of the diabetic syndrome primarily was responsible for the altered sensitivity. Other experiments were performed in an attempt to elucidate the mechanism whereby this altered sensitivity occurred. STZ-induced diabetes or dextrose-induced transient hyperglycemia did not have a significant effect on the duration of hexobarbital-induced anesthesia. Similarly, following 5 days treatment with phenobarbital, the duration of hexobarbital-induced anesthesia was reduced equally in both control and STZ-induced diabetic mice. STZ-induced diabetes did not alter the acute oral LD50 of nicotine. The antinociceptive potency of morphine as determined by the tail-flick test was significantly decreased (p \u3c 0.05) in STZ-induced diabetic mice and mice pretreated with equimolar doses of hypertonic dextrose or fructose. STZ-induced diabetic rats and spontaneously diabetic mice were also significantly less sensitive to the antinociceptive effects of morphine as quantitated by the tail-flick test. The ability of morphine to inhibit phenquuinone-induced writhing was attenuated in STZ-induced diabetic mice. Hypoglycemic mice were significantly more sensitive to morphine in the tail-flick test. Insulin reversal of dextrose-induced and STZ-induced diabetic hyperglycemia returned sensitivity to morphine-induced antinociception in the tail-flick test to control values. Pretreatment with the non-metabolizable sugar 3-0-methylglucose at a dose equimolar to the doses of dextrose and fructose had no effect on morphine potency. The antinociceptive potencies of phenazocine and levorphanol were altered similarly to that of morphine, but the potencies of methadone, propoxyphene and meperidine were not altered by changes in blood glucose levels. The LD50 of morphine but not methadone was significantly decreased in STZ-induced diabetic mice. These results confirm the selectivity of the STZ-induced diabetes to alter the sensitivity of morphine and not methadone, and are provocative since they show that the lethal effect of morphine is altered in the opposite direction from the antinociceptive potency. Levels of morphine in the brains of STZ-induced diabetic and insulin-treated STZ-induced diabetic mice were not significantly different from control mice. The durations of action of morphine in STZ-induced diabetic and control mice were similar, although the level of antinociception in the diabetic mice was lower at all time points. STZ-induced diabetes in mice did not alter serum osmolarity and brain water content. Mice receiving various pretreatments (STZ-induced diabetes, STZ-induced diabetes plus insulin, dextrose, fasting or fasting plus insulin) were subjected to analyses of their serum glucose levels, serum insulin levels, and brain glucose levels. From these data only blood glucose levels correlated (inversely) with the antinociceptive potency of morphine. The results of these experiments led to the hypothesis that the hyperglycemia was the aspect of diabetes principally responsible for selectively affecting the potency of certain opiate-like pharmacologic agents