A high speed Tri-Vision system for automotive applications

Purpose: Cameras are excellent ways of non-invasively monitoring the interior and exterior of vehicles. In particular, high speed stereovision and multivision systems are important for transport applications such as driver eye tracking or collision avoidance. This paper addresses the synchronisation problem which arises when multivision camera systems are used to capture the high speed motion common in such applications. Methods: An experimental, high-speed tri-vision camera system intended for real-time driver eye-blink and saccade measurement was designed, developed, implemented and tested using prototype, ultra-high dynamic range, automotive-grade image sensors specifically developed by E2V (formerly Atmel) Grenoble SA as part of the European FP6 project – sensation (advanced sensor development for attention stress, vigilance and sleep/wakefulness monitoring). Results : The developed system can sustain frame rates of 59.8 Hz at the full stereovision resolution of 1280 × 480 but this can reach 750 Hz when a 10 k pixel Region of Interest (ROI) is used, with a maximum global shutter speed of 1/48000 s and a shutter efficiency of 99.7%. The data can be reliably transmitted uncompressed over standard copper Camera-Link® cables over 5 metres. The synchronisation error between the left and right stereo images is less than 100 ps and this has been verified both electrically and optically. Synchronisation is automatically established at boot-up and maintained during resolution changes. A third camera in the set can be configured independently. The dynamic range of the 10bit sensors exceeds 123 dB with a spectral sensitivity extending well into the infra-red range. Conclusion: The system was subjected to a comprehensive testing protocol, which confirms that the salient requirements for the driver monitoring application are adequately met and in some respects, exceeded. The synchronisation technique presented may also benefit several other automotive stereovision applications including near and far-field obstacle detection and collision avoidance, road condition monitoring and others.Partially funded by the EU FP6 through the IST-507231 SENSATION project.peer-reviewe

Seasoned Equity Offerings and Stock Price Crash Risk

Using a large sample of U.S. firms during 1987–2011, we find robust evidence that the issuance of seasoned equity is associated with abnormally high future stock price crash risk. The association between seasoned equity offerings and crash risk is stronger among offerings that involve the sale of secondary shares (existing shares sold by insiders or large blockholders). We also find that recent seasoned equity issuers are far less likely to experience sudden positive price jumps relative to firms that have not recently issued equity. Our findings of elevated crash risk and diminished jump risk, when taken together, are consistent with a heightened propensity for firms to hoard bad news but not good news when issuing equity

Self-oscillations in field emission nanowire mechanical resonators: a nanometric DC-AC conversion

We report the observation of self-oscillations in a bottom-up nanoelectromechanical system (NEMS) during field emission driven by a constant applied voltage. An electromechanical model is explored that explains the phenomenon and that can be directly used to develop integrated devices. In this first study we have already achieved ~50% DC/AC (direct to alternative current) conversion. Electrical self-oscillations in NEMS open up a new path for the development of high speed, autonomous nanoresonators, and signal generators and show that field emission (FE) is a powerful tool for building new nano-components

Overcoming the barriers to implementing urban road user charging schemes

Urban road user charging offers the potential to achieve significant improvements in urban transport, but is notoriously difficult to implement. Cities need guidance on the range of factors to be considered in planning and implementing such schemes. This paper summarises the results of a 3 year programme which has collated evidence on the issues of most concern to cities. A state of the art report has provided evidence on 14 themes, ranging from objectives and design to implementation and evaluation. A set of 16 case studies has reviewed experience in design and implementation across Europe. The paper summarises their findings, provides references to more detailed information, presents the resulting policy recommendations to European, national and local government, and outlines the areas in which further research is needed

Developing pathways to low carbon land based passenger transport in Great Britain by 2050

The key aim of this paper is to examine strategic pathways to low carbon personal transport in Britain and to compare these with the current trajectory of transport policy. A 2050 baseline was established using trend information, forecasts and best evidence from the literature on response to policy intervention. A range of strategies are tested including: technological development, pricing, public transport and soft measures. We conclude that even dramatic technological advance cannot meet the more stringent targets for carbon reduction in the absence of considerable behavioural change. The most promising combinations of measures involve clear price signals to encourage both a reduction in the use of motorised transport and the development and purchase of more efficient vehicles; decarbonisation of public transport and facilitating measures to enhance access whilst reducing the need for motorised travel

What is a sustainable level of CO2 emissions from transport activity in the UK?

The paper reports on the development of UK transport targets for CO2 emissions for 2050. Five key studies containing future carbon emissions scenarios for the UK were used to establish targets for overall reductions in emissions to achieve stabilisation at 550 ppm and 450 ppm of atmospheric CO2. Two approaches were used to consider the proportion of total emissions that would be attributable to transport in the future: 26% of total emissions as now and an increase to 41% of total emissions in line with forecasts. The overall targets and expected contributions from transport were used to derive target emissions for the transport sector to be achieved by 2050, which ranged from 8.2 MtC to 25.8 MtC. Even the weakest of these targets represents a considerable reduction from current emissions levels

A Finite Difference Representation of Neutrino Radiation Hydrodynamics in Spherically Symmetric General Relativistic Space-Time

We present an implicit finite difference representation for general relativistic radiation hydrodynamics in spherical symmetry. Our code, Agile-Boltztran, solves the Boltzmann transport equation for the angular and spectral neutrino distribution functions in self-consistent simulations of stellar core collapse and postbounce evolution. It implements a dynamically adaptive grid in comoving coordinates. Most macroscopically interesting physical quantities are defined by expectation values of the distribution function. We optimize the finite differencing of the microscopic transport equation for a consistent evolution of important expectation values. We test our code in simulations launched from progenitor stars with 13 solar masses and 40 solar masses. ~0.5 s after core collapse and bounce, the protoneutron star in the latter case reaches its maximum mass and collapses further to form a black hole. When the hydrostatic gravitational contraction sets in, we find a transient increase in electron flavor neutrino luminosities due to a change in the accretion rate. The muon- and tauon-neutrino luminosities and rms energies, however, continue to rise because previously shock-heated material with a non-degenerate electron gas starts to replace the cool degenerate material at their production site. We demonstrate this by supplementing the concept of neutrinospheres with a more detailed statistical description of the origin of escaping neutrinos. We compare the evolution of the 13 solar mass progenitor star to simulations with the MGFLD approximation, based on a recently developed flux limiter. We find similar results in the postbounce phase and validate this MGFLD approach for the spherically symmetric case with standard input physics.Comment: reformatted to 63 pages, 24 figures, to be published in ApJ