Potential benefits of an adaptive forward collision warning system

Forward collision warning (FCW) systems can reduce rear-end vehicle collisions. However, if the presentation of warnings is perceived as mistimed, trust in the system is diminished and drivers become less likely to respond appropriately. In this driving simulator investigation, 45 drivers experienced two FCW systems: a non-adaptive and an adaptive FCW that adjusted the timing of its alarms according to each individual driver’s reaction time. Whilst all drivers benefited in terms of improved safety from both FCW systems, non-aggressive drivers (low sensation seeking, long followers) did not display a preference to the adaptive FCW over its non-adaptive equivalent. Furthermore, there was little evidence to suggest that the non-aggressive drivers’ performance differed with either system. Benefits of the adaptive system were demonstrated for aggressive drivers (high sensation seeking, short followers). Even though both systems reduced their likelihood of a crash to a similar extent, the aggressive drivers rated each FCW more poorly than their non-aggressive contemporaries. However, this group, with their greater risk of involvement in rear-end collisions, reported a preference for the adaptive system as they found it less irritating and stress-inducing. Achieving greater acceptance and hence likely use of a real system is fundamental to good quality FCW design

Human factors implications of vehicle automation: Current understanding and future directions

Advances in vehicle-based technology are currently progressing at an ever- increasing rate and innovations in this area are no longer restricted to Original Equipment Manufacturers or the automotive industry, with service providers such as Google and a number of research institutes in Europe and North America also offering possibilities for new approaches to mobility (see http://www.driverless-future.com/?page_id=155). The race to test the first fleet of such vehicles on public roads is currently underway, with Volvo Cars announcing the start of its Drive Me project by 2017 (Volvo Cars, 2013) and the UK Government recently encouraging cities to engage in demonstrating trials of such vehicles on public roads from January 2015 (BBC, 2014). However, the homogeneous global implementation of fully autonomous vehicles is unlikely in the near to distant future

On Unbounded Composition Operators in L2L^2-Spaces

Fundamental properties of unbounded composition operators in $L^2$-spaces are studied. Characterizations of normal and quasinormal composition operators are provided. Formally normal composition operators are shown to be normal. Composition operators generating Stieltjes moment sequences are completely characterized. The unbounded counterparts of the celebrated Lambert's characterizations of subnormality of bounded composition operators are shown to be false. Various illustrative examples are supplied

Behavioural changes in drivers experiencing highly-automated vehicle control in varying traffic conditions

Previous research has indicated that high levels of vehicle automation can result in reduced driver situation awareness, but has also highlighted potential benefits of such future vehicle designs through enhanced safety and reduced driver workload. Well-designed automation allows drivers’ visual attention to be focused away from the roadway and toward secondary, in-vehicle tasks. Such tasks may be pleasant distractions from the monotony of system monitoring. This study was undertaken to investigate the impact of voluntary secondary task uptake on the system supervisory responsibilities of drivers experiencing highly-automated vehicle control. Independent factors of Automation Level (manual control, highly-automated) and Traffic Density (light, heavy) were manipulated in a repeated-measures experimental design. 49 drivers participated using a high-fidelity driving simulator that allowed drivers to see, hear and, crucially, feel the impact of their automated vehicle handling. Drivers experiencing automation tended to refrain from behaviours that required them to temporarily retake manual control, such as overtaking, resulting in an increased journey time. Automation improved safety margins in car following, however this was restricted to conditions of light surrounding traffic. Participants did indeed become more heavily involved with the in-vehicle entertainment tasks than they were in manual driving, affording less visual attention to the road ahead. This might suggest that drivers are happy to forgo their supervisory responsibilities in preference of a more entertaining highly-automated drive. However, they did demonstrate additional attention to the roadway in heavy traffic, implying that these responsibilities are taken more seriously as the supervisory demand of vehicle automation increases. These results may dampen some concerns over driver underload with vehicle automation, assuming vehicle manufacturers embrace the need for positive system feedback and drivers also fully appreciate their supervisory obligations in such future vehicle designs

How does the environment affect fighting? The interaction between extrinsic fighting ability and resource value during contests.

An individual's performance during a fight is influenced by a combination of their capacity and willingness to compete. While willingness to fight is known to be determined by both intrinsic and extrinsic drivers, an individual's capacity to fight is generally thought of as solely intrinsic, being driven by a host of physiological factors. However, evidence indicates that variation in fighting ability can also be generated through exposure to different environmental conditions. Environmental contributions to fighting ability may be particularly important for animals living in spatially and temporally heterogeneous habitats, in which fights can occur between rivals recently exposed to different environmental conditions. The rapidly changing environment experienced within intertidal zones, for example, means that seawater parameters, including dissolved oxygen content and temperature, can vary across small spatial and temporal scales. Here we investigate the relative importance of these extrinsic contributions to fighting ability and resource value on contest dynamics in the beadlet sea anemone Actinia equina We manipulate the extrinsic fighting ability of both opponents (through dissolved oxygen concentration prior to fights) and resource value (through seawater flow rate during the fight). Our results indicate that the extrinsic fighting ability of both opponents can interact with resource value to drive escalation patterns and that extrinsic drivers can be more important in determining contest dynamics than the intrinsic traits commonly studied. Our study highlights the need to combine data on intrinsic state and extrinsic conditions in order to gain a more holistic view of the factors driving contest behaviour

Multidrug-Resistant Gram-Negative Bacteria in Burn Patients

Patients with burn injuries are at high risk for infectious complications, and infections are the most common cause of death after the first 72 h of hospitalization. Hospital-acquired infections caused by multidrug resistant (MDR) Gram-negative bacteria (GNB) in this population are concerning. Here, we evaluated carriage with MDR GNB in patients in a large tertiary-care burn intensive care unit. Twenty-nine patients in the burn unit were screened for intestinal carriage. Samples were cultured on selective media. Median time from admission to the burn unit to first sample collection was 9 days (IQR 5 – 17 days). In 21 (72%) patients, MDR GNB were recovered; the most common bacterial species isolated was Pseudomonas aeruginosa, which was found in 11/29 (38%) of patients. Two of these patients later developed bloodstream infections with P. aeruginosa. Transmission of KPC-31-producing ST22 Citrobacter freundii was detected. Samples from two patients grew genetically similar C. freundii isolates that were resistant to ceftazidime-avibactam. On analysis of whole-genome sequencing, blaKPC-31 was part of a Tn4401b transposon that was present on two different plasmids in each C. freundii isolate. Plasmid curing experiments showed that removal of both copies of blaKPC-31 was required to restore susceptibility to ceftazidime-avibactam. In summary, MDR GNB colonization is common in burn patients and patient-to-patient transmission of highly resistant GNB occurs. These results emphasize the ongoing need for infection prevention and antimicrobial stewardship efforts in this highly vulnerable population

Ten implementations of ptychography

Ptychography is an increasingly popular phase retrieval imaging technique, able to routinely deliver quantitative phase images with extended field of view at diffraction limited resolution. Different variants of this technique, like Bragg ptychography and Fourier ptychography, have also been developed and applied to various fields. Here we experimentally demonstrate 10 ways to implement the conventional real space transmission ptychography, and compare their properties to provide a guide to choosing the optimal setup for a specific application

Driving performance and driver discomfort in an elevated and standard driving position during a driving simulation

This article was accepted for publication in Applied Ergonomics [© Elsevier] and the definitive version is available at: http://dx.doi.org/10.1016/j.apergo.2015.01.003The primary purposes of a vehicle driver’s seat, is to allow them to complete the driving task comfortably and safely. Within each class of vehicle (e.g. passenger, commercial, industrial, agricultural), there is an expected driving position to which a vehicle cabin is designed. This paper reports a study that compares two driving positions, in relation to Light Commercial Vehicles (LCVs), in terms of driver performance and driver discomfort. In the ‘elevated’ driving position, the seat is higher than usually used in road vehicles; this is compared to a standard driving position replicating the layout for a commercially available vehicle. It is shown that for a sample of 12 drivers, the elevated position did not, in general, show more discomfort than the standard position over a 60 minutes driving simulation, although discomfort increased with duration. There were no adverse effects shown for emergency stop reaction time or for driver headway for the elevated posture compared to the standard posture. The only body part that showed greater discomfort for the elevated posture compared to the standard posture was the right ankle. A second experiment confirmed that for 12 subjects, a higher pedal stiffness eliminated the ankle discomfort problem

Functional approach to 2+1 dimensional gravity coupled to particles

The quantum gravity problem of N point particles interacting with the gravitational field in 2+1 dimensions is approached working out the phase-space functional integral. The maximally slicing gauge is adopted for a non compact open universe with the topology of the plane. The conjugate momenta to the gravitational field are related to a class of meromorphic quadratic differentials. The boundary term for the non compact space is worked out in detail. In the extraction of the physical degrees of freedom functional determinants related to the puncture formulation of string theory occur and cancel out in the final reduction. Finally the ordering problem in the definition of the functional integral is discussed.Comment: 29 pages LaTe