1,807 research outputs found
Geodatabase for the Hydrogeologic Atlas of Southwest Travis County, Central Texas
No full textThe Barton Springs/Edwards Aquifer Conservation District (BSEACD), in cooperation with Travis County, compiled existing and new hydrogeologic data to evaluate groundwater resources in southwestern Travis County (SWTC). Analysis and interpretation of these data provide the foundation for hydrogeologic evaluations presented in the Hydrogeologic Atlas of Southwest Travis County, Central Texas (Hunt et al., 2020), which refines the area’s hydrogeologic framework and conceptual model, establishes current aquifer conditions, and estimates groundwater use in SWTC.
Authors of the Atlas created a geodatabase to provide a single repository for the source data of the study. The geodatabase may help provide baseline data for future groundwater studies of the region. An accompanying report (Cockrell et al., 2020) describes the development of the geodatabase, documents data sources, and describes the data analyses performed
Inter- and intra-driver variability in lane change behaviour
No full textLane change manoeuvres are known to vary widely in lane change duration. This is thought to be an effect of the surrounding vehicles and personal preference of drivers. However, little is known about the effect on steering behaviour during a lane change manoeuvre. Moreover, the relation of the effect of traffic to inter- and intra-driver variability is unknown. This study focuses on quantifying inter- and intra-driver variability in lane change duration and steering behaviour during lane changes in two different traffic scenarios. In an exploratory study, 21 participants drove 30 lane change manoeuvres in a 6 DoF moving base driving simulator. Two scenarios were used: a closing gap in the target lane and a constant gap in the target lane, with 15 repetitions per scenario. The results show high inter-driver and intra-driver variability, for both lane change duration (M=6.34 s SD-inter=0.90 s SD-intra=1.26 s) and steering behaviour (e.g. maximum steering wheel angle M=4.14 deg SD-inter=1.62 deg SD-intra=1.34 deg). The effect of the scenario was not significant for lane change duration and maximum steering wheel angles. Additionally, it was shown that lane change duration only has a medium correlation with the maximum steering wheel angle (Pearson R(585)=-.48, p\textless0.001). Furthermore, the mean and variability of the lane change duration decreased when lane changes were initiated with a shorter distance to the slow lead vehicle. Concluding, the lane change duration does not fully determine steering behaviour during a lane change, making it an unsuitable metric for determining human-like lane change trajectories. It is therefore proposed to create trajectories based on steering behaviour. It seems that drivers exhibit high variability in lane change behaviour when spatio-temporal criticality with respect to traffic is low. Higher spatio-temporal criticality limits the mean and variability of the lane change duration. Future work should determine whether this variability is the result of driver preference or indifference. Additionally, future work should implement and test human-like lane change trajectories based on steering behaviour as opposed to lane change duration.Mechanical Engineering | Vehicle Engineerin
On the improvement of the rifle, as a weapon for general use / by Lieut.-Colonel Lane-Fox, Grenadier Guards.
No full text'Read at the United Service Institution, on 14th June, 1858, Colonel the Hon. James Lindsay in the Chair' - t.p.; Signatures: B2, C2, D2; Electronic reproduction. Canberra, A.C.T. : National Library of Australia, 2011.; Library copy has marks in margins and signature on title page. "A brief account of the history of the rifle and of the experiemnets and trials which have accompanied its introduction into the English Army.The remarks ... are principally from a private journal which I [author] had kept during the course of experiements in which I [author] have been engaged at Woolwich, Enfield, Hythe and Malta, during the six years, commencing in 1851 and ending in 1857." -- [p.3]
Lane Determination with GPS Precise Point Positioning
No full textModern intelligent transport solutions can achieve an improvement of traffic flow on motorways. With lane-specific measurements and lane-specific control, more measures are possible. Single frequency precise point positioning (PPP) is a newly developed and affordable technique to achieve an improved position accuracy compared with global positioning system (GPS) standalone positioning. GPS-PPP allows for sub-meter accurate positioning, in real time, of vehicles on a motorway. This paper tests this technique in real life; moreover, it presents a methodology to map the lanes on a motorway using data collected by this technique. The methodology exploits the high accuracy and the fact that the most driving is within a lane. In a field test, a GPS-PPP equipped vehicle drives a specific motorway stretch 100 times, for which the GPS-PPP trajectory data are collected. Using these data, the positions and the widths of different lanes are successfully estimated. Comparison with the ground truth shows a dm accuracy. With the parametrized lanes, vehicles can be tracked down to a lane with the GPS-PPP device.</p
Lane County criminal justice report
No full textThis archived document is maintained by the Oregon State Library as part of the Oregon Documents Depository Program. It is for informational purposes and may not be suitable for legal purposes.Title from PDF cover (viewed on July 18, 2014)"The Criminal Justice Commission convened a study group to look at county level data and develop quantitative measures of public safety services. This group has looked at offense, arrest, jail bed, prison intake, and sworn officer data. We focused on conditions in Lane County."-page 2Includes bibliographical referencesMode of access: Internet from the Oregon Government Publications Collection.Text in Englis
Identifying Lane Changes Automatically using the GPS Sensor of Portable Devices
No full textAutomatic lane change identification can be used in warning systems that alert the driver when drifting off-lane, or in lane-specific navigation systems. Furthermore, they may help road authorities plan better road network design and infrastructure. Though lane-departure warning systems are already commercially available, these systems rely on on-board vehicle sensors. The availability of such systems can be increased if it became available to owners of smartphones or navigation devices. In this thesis, I propose and test several methods that rely solely on GPS data originating from portable devices (two smartphones, a GPS-equipped GoPro Max, and a USB GPS receiver), recorded during test rides on a Dutch highway (42.8 km) with a total of 64 lane changes. The methods rely on observing changes in the lateral offset between the GPS trajectories and the road geometry. The resulting identification accuracy of the best performing algorithm was achieved using the GoPro Max with an overall F1 score (harmonic mean of precision and recall) of 0.9 on the validation data using the signal of filtered projected lateral distance. It is concluded that GPS-equipped portable devices could be a suitable choice for identifying lane changes, provided there is improvement in the quality of GPS receiver chips with higher data collection frequency such as the ones used in GoPro Max.Mechanical Engineerin
Continuous auditory feedback on the status of adaptive cruise control, lane deviation, and time headway: An acceptable support for truck drivers?
No full textThe number of trucks that are equipped with driver assistance systems is increasing. These driver assistance systems typically offer binary auditory warnings or notifications upon lane departure, close headway, or automation (de)activation. Such binary sounds may annoy the driver if presented frequently. Truck drivers are well accustomed to the sound of the engine and wind in the cabin. Based on the premise that continuous sounds are more natural than binary warnings, we propose continuous auditory feedback on the status of adaptive cruise control, lane offset, and headway, which blends with the engine and wind sounds that are already present in the cabin. An on-road study with 23 truck drivers was performed, where participants were presented with the additional sounds in isolation from each other and in combination. Results showed that the sounds were easy to understand and that the lane-offset sound was regarded as somewhat useful. Systems with feedback on the status of adaptive cruise control and headway were seen as not useful. Participants overall preferred a silent cabin and expressed displeasure with the idea of being presented with extra sounds on a continuous basis. Suggestions are provided for designing less intrusive continuous auditory feedback.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Human-Robot Interactio
Automated lane changing using deep reinforcement learning: a user-acceptance case study
No full textLane change decision-making is an important challenge for automated vehicles, urging the need for high performance algorithms that are able to handle complex traffic situations. Deep reinforcement learning (DRL), a machine learning method based on artificial neural networks, has recently become a popular choice for modelling the lane change decision-making process, outperforming various traditional rule-based models. So far, performance has often been expressed in terms of achieved average speed, absence of collisions or merging success rate. However, no studies have investigated how humans will react to the resulting behavior as potential occupants. This study addresses this research gap by validating a self-developed DRL-based lane changing model (trained using proximal policy optimization) from a technology acceptance perspective through an online crowdsourcing experiment. Participants (N=1085) viewed a random subset of 32 out of 120 videos of an automated vehicle driving on a three-lane highway with varying traffic densities featuring our proposed model or a baseline policy (i.e. a state-of-the-art rule-based model, MOBIL). They were tasked to press a response key if the decision-making was deemed undesirable and subsequently rated the vehicle's behavior along four acceptance constructs (performance expectancy, safety, human-likeness and reliability) on a scale of 1 to 5. Results showed that the proposed model caused a significantly lower amount of disagreements and was rated significantly higher on all four acceptance constructs compared to the baseline policy. Moreover, considerable differences between individual disagreement rates were observed for both models. Our findings offer prospects for the practical application of DRL-based lane change models in a use-case scenario, depending on the user. Further research is necessary to examine whether these observations hold in other (more complex) traffic situations. Additionally, we recommend combining DRL with other modelling techniques that allow for personalization of behavioral parameters, such as imitation learning.Mechanical Engineerin
A methodology for the assessment of Operational Design Domain of Lane Keeping Assistance system equipped vehicles: The case of Tesla Model S
No full textIn this research, a methodology to assess the Operational Design Domain of Lane Keeping Assistance System equipped vehicles is developed. The method is mainly intended for use by manufacturers of semi-automated vehicles to assess the situations and conditions in which their lane keeping systems that are already available in the market, can and cannot perform. The methodology is implemented to a real-road case study using an instrumented Tesla Model S and assesses its Autosteer system at certain pre-specified situations. It involves assessment of the situations based on three main components: lane keeping performance of the system in these situations; the lateral objective risks of driving in these situations; and the driver’s attitude/behaviour using questionnaires at three stages of testing
Chi Square
No full textThis resource, created by author David M. Lane, defines and explains Chi square. It takes the user through 5 different categories: testing differences between p and pi, more than two categories, chi-square test of independence, reporting results, exercises. This basic resource provides students with a much greater understanding of this testing process. Overall, it would be good for any statistics classroom
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