177,093 research outputs found
Supplementary materials for the article: How do drivers merge heavy goods vehicles onto freeways? A semi-structured interview unveiling needs for communication and support.
No full textSupplementary materials for the article Dreger, F. A., De Winter, J. C. F., & Happee, R. How do drivers merge heavy goods vehicles onto freeways? A semi-structured interview unveiling needs for communication and support. Cognition, Technology and Work
Supplementary materials for the article: Prediction of effort and eye movement measures from driving scene components
No full textSupplementary materials for the article: Cabrall, C. D. D., Happee, R., & De Winter, J. C. F. (2019). Prediction of effort and eye movement measures from driving scene components. Transportation Research Part F.
TU Delft, Faculty of Mechanical, Maritime and Materials Engineering (3mE), Department of Cognitive Robotic
Effects of adaptive cruise control and highly automated driving on workload and situation awareness: a review of the empirical evidence
No full textAdaptive cruise control (ACC), a driver assistance system that controls longitudinal motion, has been introduced in consumer cars in 1995. A next milestone is highly automated driving (HAD), a system that automates both longitudinal and lateral motion. We investigated the effects of ACC and HAD on drivers’ workload and situation awareness through a meta-analysis and narrative review of simulator and on-road studies. Based on a total of 32 studies, the unweighted mean self-reported workload was 43.5% for manual driving, 38.6% for ACC driving, and 22.7% for HAD (0% = minimum, 100 = maximum on the NASA Task Load Index or Rating Scale Mental Effort). Based on 12 studies, the number of tasks completed on an in-vehicle display relative to manual driving (100%) was 112% for ACC and 261% for HAD. Drivers of a highly automated car, and to a lesser extent ACC drivers, are likely to pick up tasks that are unrelated to driving. Both ACC and HAD can result in improved situation awareness compared to manual driving if drivers are motivated or instructed to detect objects in the environment. However, if drivers are engaged in non-driving tasks, situation awareness deteriorates for ACC and HAD compared to manual driving. The results of this review are consistent with the hypothesis that, from a Human Factors perspective, HAD is markedly different from ACC driving, because the driver of a highly automated car has the possibility, for better or worse, to divert attention to secondary tasks, whereas an ACC driver still has to attend to the roadway
Supplementary material for the paper: Take-over quality: Assessing the effects of time budget and traffic density with the help of a trajectory-planning method.
No full textSupplementary materials for the paper
Doubek, F., Loosveld, E., Happee, R., & De Winter, J. C. F. (2020). Take-over quality: Assessing the effects of time budget and traffic density with the help of a trajectory-planning method. Journal of Advanced Transportation
Measurement of the lateral characteristics and identification of the Magic Formula parameters of city and cargo bicycle tyres
No full textThe paper presents measurements of the lateral force and self-aligning torque from cargo and city bicycle tyres. Based on the experimental data, we have determined the parameters for the Magic Formula model, for lateral force and self-aligning torque. We performed tests with VeTyT, an indoor test rig specific for bicycle tyres, under different vertical loads (ranging from 343 N to 526 N), camber angles (−5, 0, 5) deg and inflation pressure (from 300 kPa to 500 kPa). For each condition, we evaluated the cornering stiffness and found that it generally decreases with the increase in inflation pressure for the tour/city bicycle tyres. However, the cargo tyre tested showed an opposite trend, with an increase in the cornering stiffness as the inflation pressure increased from 300 kPa to 400 kPa
Optimisation of vehicle passive safety for occupants with varying anthropometry
No full textA method has been devloped to generate models representing subjects of varying anthropometry. This method has been applied to crash-dummy models, and will in the future also be applied to human body models. The 1st step of the method is to generate a set of target anthropomethry parameters from a relevant population. The 2nd step is to scale an existing model towards the desired anthropometry. Different scaling factors are being applied for the different body parts and dimensions. These factors are used to derive body dimensions, mass and inertia properties, joint resistance and contact resistance parameters. For this study on adult subjects it has been assumed that material properties are invariant with subject size. Quasi-static simulations were performed to confirm that the resulting stiffness of complete body parts obey the scaling rules applied to the model components. The design of a vehicle has been evaluated with respect to passive safety for a wide range of occupant sizes. Starting point was a set of validated frontal impact simulations including Hybrid III dummies. These simulations were repeated with occupant models of varying size and weight. The model setup for the frontal impact simulation was similar to the model used in the study of Michaelsen, 1997. The frontal impact simulations have shown a wide range of results for the different types of occupant. Due to different seat positions and body proportions the injury parameters exceed the range of results found for standard dummies
The load path from upper legs to chest in the Hybrid III dummy: experiments and simulations
No full textIt has been shown that the design of the Hybrid III dummy's hip joint can cause high spikes in the chest accelerations. These spikes are generated when the pelvis rotation is suddenly stopped by the bottoming out of the hip joint. This creates large lumbar shear and tension forces which act to resist forward movement of the dummy's chest. This problem has partly been resolved by the introduction of 'modified femurs'. However, even with modified femurs, high peaks have still been observed in chest accelerations of some front barrier crashes. In order to analyze the load path from upper legs to chest, dynamic experiments have been performed on the hip joint (with modified femurs and with standard femurs), on the isolated lumbar spine and on a partial dummy consisting of upper legs, torso, neck and head. These tests have been used to significantly improve an existing model of the dummy. In the hip joint, a considerable rate-dependency was found and the adjustment of hip friction was found to be an important factor. For different lumbar spines from the same manufacturer, major differences in response were found. These differences between dummy parts are a concern for reproducibility of full dummy tests. A sensitivity analysis showed that such dummy related factors lead to variations in the order of 2-8% for peak chest acceleration and chest deflection, but lead to much larger variations in lumbar loads
Appropriate Similarity Measures for Author Cocitation Analysis
No full textWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Horizontal Semicircular Canal Orientation and the 3-D Vestibulo-Ocular Reflex
No full textGoal. The three-dimensional vestibulo-ocular reflex (3-D VOR) is responsible for the maintenance of stable vision through generating compensatory eye movements in response to head movements. The main functional components of the 3-D VOR are the semicircular canals. The anatomy of the three canals is complicated, requiring the definition of several natural coordinate systems in order to assess the canals' functionality. Most notably, the horizontal canals form a significant angle (25°) with respect to the earth-horizontal (E-H) while the head is upright. The goal of this study was to determine the influence of head pitch orientation on the quality of the VOR, and thus to identify the 3-D VOR dependence on the canal anatomy and orientation. Methods. Eight healthy upright seated subjects underwent whole-body sinusoidal and transient stimulation delivered by a six degree of freedom (6-DOF) motion platform. Small-amplitude sinusoidal oscillation was delivered around the yaw axis and axes in the horizontal plane between roll and pitch at increments of 22.5°. Transients were delivered in yaw, roll and pitch and in the vertical canal planes. This sequence of stimuli was repeated for the subject with his/her head under three different initial positions: upright, pitched nose down 16°and 25°, aligning the horizontal canal prime direction and maximum response direction with the E-H, respectively. 3-D scleral search coils were used for the recording of eye movements. Results. For sinusoidal stimulation around axes in the horizontal plane, a decline in gain and an increase in misalignment were found for increasing downward head pitch, in the light as well as in darkness. All component gains had lower values in darkness than in light. For vertical axis rotation, this decrease in gain and increase in misalignment was also present, except for the torsion component which increased with both upward and downward (from upright) pitch. Transient stimulation yielded overall lower gains than sinusoidal stimulation. No significant differences between the different head pitch orientations were found for vertical axis stimulation. For transients around axes in the horizontal plane however, the horizontal component gain increased with increasing nose-down pitch, while overall the vertical component decreased. Conclusions. The incongruence between the mathematically modelled coordinate systems of the semicircular canals and the obtained results in terms of gain and misalignment, suggests the contribution of other mechanisms to the 3-D VOR. The gravity-induced otolith-mediated VOR is likely to have an additional effect with the head pitched. The inhibitory effect of the otolith-mediated gravity vector on the torsional eye position is a possible explanation for the reduction in gain for sinusoidal rotation around axes in the horizontal plane. The opposite is seen during transient stimulation, which could be attributed to the otolith organs' low-pass behaviour.Specialization: BiomechatronicsBiomechanical EngineeringMechanical, Maritime and Materials Engineerin
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