1,720,962 research outputs found
Definition of simulated driving tests for the evaluation of drivers' reactions and responses
No full textObjective: This paper aims at identifying the most significant measures in two perception—response (PR) tests performed at a driving simulator: a braking test and a lateral skid test, which was developed in this work.
Methods: 48 subjects (26 females and 22 males) with a mean age of 24.9±3.0 years were enrolled for this study. They were asked to perform a drive on the driving simulator at the University of Pisa (Italy) following a specific test protocol, including 8–10 braking tests and 8–10 lateral skid tests. Driver input signals and vehicle model signals were recorded during the drives and analysed to extract some measures, such as the reaction time, the first response time, etc. Following a statistical procedure (based on ANOVA and post-hoc tests), all test measures (3 for the braking test and 8 for the lateral skid test) were analysed in terms of statistically significant differences among different drivers. The presented procedure allows to evaluate the capability of a given test to distinguish among different drivers.
Results: In the braking test, the reaction time showed a high dispersion within the results of the single drivers, leading to just 4.8% of statistically significant driver pairs (using the Games-Howell post-hoc test), whereas the pedal transition time scored 31.9%. In the lateral skid test, 28.5% of the two-by-two comparisons showed significantly different reaction times, 19.5% had different response times, 35.2% had a different second peak of the steering wheel signal and 33% showed different values of the integral of the steering wheel signal.
Conclusions: For the braking test, which has been widely employed in similar forms in the literature, it was shown how the reaction time, with respect to the pedal transition time, can have a higher dispersion due to the influence of external factors. For the lateral skid test, the following measures were identified as the most significant for application studies: the reaction time for the reaction phase, the second peak of the steering wheel angle for the first instinctive response and the integral of the steering wheel angle for the complete response. The methodology, which was used to analyse the test measures, was founded on statistically based and objective evaluation criteria and could be applied to other tests. Even if obtained with a fixed base simulator, the obtained results represent useful information for applications of the presented PR tests in experimental campaigns with driving simulators.
Supplemental materials are available for this article. Go to the publisher's online edition of Traffic Injury Prevention to view the supplemental file
Evaluation of drivers' attention level by a driving simulator
No full textDiagnosis systems for evaluating driver's attention level have become very important in the last years and have gained an increasing attention from automotive manufacturers; indeed, traffic crashes represent worldwide one of the main public health problems and many accidents are demonstrated to be due to drivers' hypovilance. In this work a driving simulator and specific test tools were developed to validate the possibility of monitoring the drivers' attention level and capability.
The driving simulator is equipped with a fixed cockpit and a single front screen. The cockpit reproduces the man-machine interface of a typical medium class car with automatic transmission, i.e. the driver interacts with the simulator by means of the throttle and brake pedals and the steering wheel. The pedals are endowed with passive feedback systems, whereas an electric motor applies an active feedback torque on the steering wheel.
From the software point of view, the simulator is managed by four PCs connected by a LAN. Two of them are dedicated to the simulation of vehicle dynamics and for data logging, while the other two run the graphical scenario software. This includes a motorway area connected to an urban area with an autonomous traffic.
The vehicle model was built with a block architecture in the Matlab/Simulink environment and is run in real-time by using the xPC Target toolbox. A specific block, consisting of an in-house developed 14 d.o.f. model, was set up to represents vehicle dynamics.
The driving simulator is currently employed in experimental campaigns acquiring about 60 signals of driver's input and vehicle quantities. In order to evaluate the drivers' attention level, two specific tests were developed, which aim at measuring the drivers' reaction time and ability in sudden events such as a brake manoeuvre or a sudden lateral skid.
In the paper the driving simulator hardware and software are presented. The tests procedures, which were developed to investigate the driver's attention, are also discussed with reference to some tests
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe 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
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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