Simulation study of driver stress and performance to an unexpected event

Abstract In this paper, we study the effect of unexpected behaviour of a Driving Assistance System (DAS) on the driver, during a common task of driving in a virtual environment. The considered system is an electrical steering, which allows drivers to reduce efforts needed to handle the steering wheel during cornering manoeuvres. A failure of such system could produce a sudden and permanent loss of steering assistance and make the steering wheel more difficult to turn. The objective of this study is to determine how this event will affect the driver's performance, particularly in terms of stress and visual performance. At last, drivers are able to adapt to this kind of event if it occurs before entering a curve. Moreover, an increase of muscle stiffness has been observed during lane change manoeuvres, which provide a more robust control of the steering wheel to external perturbations. At last drivers are able to manage a sudden increase of stress. The experiment was conducted on the ULTIMATE dynamic driving simulator developed by the Technical Centre for Simulation of RENAULT. The simulator has been fitted with a new steering force feedback system improving dynamical performance. This simulator upgrade and assessment methodology will be presented in more details in this paper. The driver behaviour was studied through questionnaires to assess the stress produced by the different situations. Detection and/or recognition of objects in the virtual scene give cues on the DAS failure effects on the driver's visual attention. In order to quantify the drivers' performance, objective indicators such as steering reversal rate, steering entropy and time-to-lane-crossing were also used. In spite of the unexpected steering event, all drivers have achieved their driving task, without leaving the road. Results show an increase of stress for drivers when the unexpected event occurs. We also notice an alteration of the visual performance revealed by drivers' difficulties to recognize critical objects in the environment. This study suggests that high-performance driving simulators may be valuable to assess the effects of safety-critical events on driving performance. Résumé Dans cet article, nous étudions l'effet sur le conducteur d'un comportement inattendu d'un système d'aide à la conduite (DAS) et ceci lors d'une tâche de conduite ordinaire en environnement virtuel. Le système retenu est une direction assistée électrique qui permet au conducteur de réduire les efforts nécessaires à produire pour le maniement du volant en virage. Une défaillance d'un tel système peut produire une perte soudaine et permanente d'assistance et rendre ainsi le volant plus difficile à tourner. L'objectif de cette étude est de déterminer l'impact de ce type d'évènement sur les performances du conducteur. Seront considérés en particulier la performance visuelle et la production de stress. Il a été constaté que lorsque cet évènement apparaît avant l'entrée en virage, les conducteurs sont capables de s'y adapter. De plus, une augmentation de la raideur des muscles du bras a été observée lors de manoeuvres de changement de file, ce qui rend le contrôle du volant plus robuste à des perturbations extérieures. Enfin, il semble que les conducteurs sont capables de gérer un stress soudain et de courte durée. L'expérimentation a été réalisée sur le simulateur de conduite dynamique ULTIMATE développé au Centre Technique de Simulation de RENAULT. Le simulateur s'est vu doté d'un nouveau restituteur d'effort pour le volant, offrant des performances dynamiques supérieures au précédent restituteur. L'installation et la validation de ce nouveau matériel sera présentée dans de plus amples détails. Le comportement des conducteurs a été étudié au travers de questionnaires afin d'évaluer la production de stress lors des différentes situations. La détection et/ou la reconnaissance d'objets dans la scène virtuelle procure des indices quant aux effets sur l'attention visuelle du conducteur de la défaillance du système d'assistance. Dans le but de quantifier la performance de conduite, des indicateurs tels que le Steering Reversal Rate, le Steering Entropy et le Time-to-Line-Crossing ont été utilisés. Malgré que l'évènement soit inattendu, tous les conducteurs ont réussi à terminer leur tâche de conduite sans quitter la route. Les résultats montrent une augmentation du stress lorsque cet évènement apparaît. Remarquons aussi l'altération de l'attention visuelle des conducteurs de part leur difficulté à reconnaître les objets de l'environnement. Cette étude suggère que les simulateurs de conduite à hautes performances autorisent l'évaluation des effets sur la performance de conduite d'évènements critiques en termes de sécurité

The Congolobe project, a multidisciplinary study of Congo deep-sea fan lobe complex: Overview of methods, strategies, observations and sampling

The presently active region of the Congo deep-sea fan (around 330,000 km(2)), called the terminal lobes or lobe complex, covers an area of 2500 km(2) at 4700-5100 m water depth and 750-800 km offshore. It is a unique sedimentary area in the world ocean fed by a submarine canyon and a channel-levee system which presently deliver large amounts of organic carbon originating from the Congo River by turbidity currents. This particularity is due to the deep incision of the shelf by the Congo canyon, up to 30 km into the estuary, which funnels the Congo River sediments into the deep-sea. The connection between the river and the canyon is unique for major world rivers. In 2011, two cruises (WACS leg 2 and Congolobe) were conducted to simultaneously investigate the geology, organic and inorganic geochemistry, and micro- and macro-biology of the terminal lobes of the Congo deep-sea fan. Using this multidisciplinary approach, the morpho-sedimentary features of the lobes were characterized along with the origin and reactivity of organic matter, the recycling and burial of biogenic compounds, the diversity and function of bacterial and archaeal communities within the sediment, and the biodiversity and functioning of the faunal assemblages on the seafloor. Six different sites were selected for this study: Four distributed along the active channel from the lobe complex entrance to the outer rim of the sediment deposition zone, and two positioned cross-axis and at increasing distance from the active channel, thus providing a gradient in turbidite particle delivery and sediment age. This paper aims to provide the general context of this multidisciplinary study. It describes the general features of the site and the overall sampling strategy and provides the initial habitat observations to guide the other in-depth investigations presented in this special issue. Detailed bathymetry of each sampling site using 0.1-1 m resolution multibeam obtained with a remotely operated vehicle (ROV) shows progressive widening and smoothing of the channel-levees with increasing depth and reveals a complex morphology with channel bifurcations, erosional features and massive deposits. Dense ecosystems surveyed in the study area gather high density clusters of two large-sized species of symbiotic Vesicomyidae bivalves and microbial mats. These assemblages, which are rarely observed in sedimentary zones, resemble those based on chemosynthesis at cold-seep sites, such as the active pockmarks encountered along the Congo margin, and share with these sites the dominant vesicomyid species Christineconcha regab. Sedimentation rates estimated in the lobe complex range between 0.5 and 10 cm yr(-1), which is 2-3 orders of magnitude higher than values generally encountered at abyssal depths. The bathymetry, faunal assemblages and sedimentation rates make the Congo lobe complex a highly peculiar deep-sea habitat driven by high inputs of terrigenous material delivered by the Congo channel-levee system. (c) 2016 Elsevier Ltd. All rights reserved.ZAIANGOANR Congolobe (ANR Blanc SIMI5-6) [11 BS56 030]IFREMERCEA through LSCEU.S. National Science Foundation [OCE-0831156]info:eu-repo/semantics/acceptedVersio

Evidence for the Role of Horizontal Transfer in Generating pVT1, a Large Mosaic Conjugative Plasmid from the Clam Pathogen, Vibrio tapetis

The marine bacterium Vibrio tapetis is the causative agent of the brown ring disease, which affects the clam Ruditapes philippinarum and causes heavy economic losses in North of Europe and in Eastern Asia. Further characterization of V. tapetis isolates showed that all the investigated strains harbored at least one large plasmid. We determined the sequence of the 82,266 bp plasmid pVT1 from the CECT4600T reference strain and analyzed its genetic content. pVT1 is a mosaic plasmid closely related to several conjugative plasmids isolated from Vibrio vulnificus strains and was shown to be itself conjugative in Vibrios. In addition, it contains DNA regions that have similarity with several other plasmids from marine bacteria (Vibrio sp., Shewanella sp., Listonella anguillarum and Photobacterium profundum). pVT1 contains a number of mobile elements, including twelve Insertion Sequences or inactivated IS genes and an RS1 phage element related to the CTXphi phage of V. cholerae. The genetic organization of pVT1 underscores an important role of horizontal gene transfer through conjugative plasmid shuffling and transposition events in the acquisition of new genetic resources and in generating the pVT1 modular organization. In addition, pVT1 presents a copy number of 9, relatively high for a conjugative plasmid, and appears to belong to a new type of replicon, which may be specific to Vibrionaceae and Shewanelleacae

Introduction: Human ecology in the Himalaya

Knowledge of human adaptation in the Himalayas has developed more slowly than that for other world mountain systems. At the same time, the opening of the region to research has focused attention toward description in a “natural history” mode until quite recently. Where these studies have addressed issues of adaptation they have tended to do so more as a heuristic tool rather than in terms of contributing to the development of adaptive perspectives from a uniquely Himalayan vantage point. The contributions to this special issue suggest some of Himalayan cultural ecology's new themes as it more directly assumes a truly processual approach that incorporates the individual and domestic dimensions of adaptation within historical and social contexts .Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/44482/1/10745_2004_Article_BF00889710.pd

Eco-driving performance assessment with in-car visual and haptic feedback assistance

In this experiment, 28 participants completed an urban driving task in a highly immersive driving simulator at Renault’s Technical Centre for Simulation. This simulator provides a 150 deg field of view in a fully instrumented cockpit. Two different eco-driving assistance devices were added: a visual display on the midconsole and a force feedback system on the gas pedal, in order to apply an additionnal reaction torque on drivers’ foot. The feedback information was computed by comparing the car’s instant acceleration with an optimal acceleration level based on a proprietary consumption model of a Renault diesel engine. This experiment has three main goals: I. Assess the contribution of verbal instructions to eco-driving performance; II. Quantify the additional contribution generated by two eco-driving assistance systems (visual and haptic); III. Measure drivers’ acceptance of haptic eco-driving assistance system. Basic eco-driving instructions, such as changing gears under 2000 Rpm, yield significant decrease of polluting emissions. Assisting drivers with visual, haptic, or visual-haptic on-board devices, in addition to low engine speed verbal instructions, lead to supplementary significant savings of polluting emissions. There is no significant difference between assistance feedback type; suggesting that the haptic feedback provides the same ecoperformance as visual feedback. In particular, subjects show good adaptation to the haptic feedback pedal at first utilization of the system. They apparently relied more on haptic modality to achieve the eco-driving task, when they used both visual and haptic assistance