1,721,054 research outputs found
Driver sleepiness: Creation, consequences, and countermeasures
No full text<b>Overview</b>\ud
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• Creation\ud
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– Sleep/wake cycle \ud
– Influences on sleepiness\ud
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• Consequences\ud
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– Effects from sleepiness\ud
– Arousal influences\ud
– Signs of sleepiness\ud
– Sleepiness crash risk\ud
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• Countermeasures\ud
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– Effectiveness of various sleepiness countermeasure
Motivation to continue driving while sleepy: The effects on sleepiness and performance levels
No full textDriver sleepiness contributes to a substantial proportion of fatal and severe road crashes and potentially contributes to a greater proportion of less serious crashes. A number of survey studies have reported that some drivers choose to continue to drive while sleepy despite being aware of an increasing level of sleepiness. Additionally, drivers’ motivations to continue driving while sleepy is a stronger predictor of sleepy driving behaviours, overshadowing crash risk perception of sleepy driving. While several survey studies have quantified self-reported aspects of continuing to drive while sleepy, there appears to be lack of studies that examine the actual psychophysiological and performance sequela of continuing to drive when sleepy. The current study sought to examine the effect motivating oneself to apply extra effort to the task of driving when sleepy on physiological and subjective sleepiness and driving performance. In total, 18 participants undertook a 60 minute Hazard Perception test on four occasions – on the four occasions, the participants motivation level (motivated and non-motivated) and sleepiness level (sleepy-alert) were experimentally manipulated. Physiological, subjective, and performance indices of sleepiness were obtained with respect to the effects of the manipulation of motivation and sleepiness levels. The results suggest that no effect of motivation was observed in the Hazard Perception test data. Physiological and subjective sleepiness were both greater in the sleepy conditions than the alert conditions and over the duration of both tests, sleepiness levels increased regardless of the motivation or sleepiness conditions. Considered together, these findings suggest that sleepiness is very resilient to motivations to stay alert and improve performance levels. The present results suggest that continuing to drive while sleepy whereby the drivers motivate themself to apply extra effort to the task of driving is a dangerous driving behaviour
The sleep and wake drives : exploring the genetic and psychophysiological aspects of sleepiness, motivation, and performance
No full textThis research program examined the factors of motivation and genetic variations for their effects on sleepiness and performance. The results suggest that certain genetic variations were found to influence aspects of physiological and subjective sleepiness as well as performance outcomes. Motivation had no effect on performance when partially sleep deprived, but motivation improved task performance on a low-order cognitive task when fully rested. The results suggest sleepiness is resistant to motivation to improve performance. As such, drivers who continue to drive while sleepy by applying extra effort to the task of driving are engaging in a risky driving behaviour
Stop and revive? : the effectiveness of nap and active rest breaks for reducing driver sleepiness
No full textThe incidence of sleep-related crashes has been estimated to account for approximately 20% of all fatal and severe crashes. The use of sleepiness countermeasures by drivers is an important component to reduce the incidence rates of sleep-related crashes. Taking a brief nap and stopping for a rest break are two highly publicised countermeasures for driver sleepiness and are also believed by drivers to be the most effective countermeasures. Despite this belief, there is scarce evidence to support the utility of these countermeasures for reducing driver sleepiness levels. Therefore, determining the effectiveness of these countermeasures is an important road safety concern. The current study utilised a young adult sample (N = 20) to investigate the effectiveness of a nap and an active rest break. The countermeasures effects were evaluated by physiological, behavioural (hazard perception skill), and subjective measures previously found sensitive to sleepiness. Participants initially completed two hours of a simulated driving task followed by a 15 minute nap opportunity or a 15 minute active rest break that included 10 minutes of brisk walking. After the break, participants completed one final hour of the simulated driving task. A within-subjects design was used so that each participant completed both the nap and the active rest break conditions on separate occasions. The analyses revealed that only the nap break provided any meaningful reduction in physiological sleepiness, reduced subjective sleepiness levels, and maintained hazard perception performance. In contrast, the active rest break had no effect for reducing physiological sleepiness and resulted in a decrement in hazard perception performance (i.e., an increase of reaction time latencies), with a transient reduction in subjective sleepiness levels. A number of theoretical, empirical and practical issues were identified by the current study
Too sleepy to drive : self-perception and regulation of driving when sleepy
No full textBackground: Sleepiness is a direct contributor to a substantial proportion of fatal and severe road cashes. A number of technological solutions designed to detect sleepiness have been developed, but self-awareness of increasing sleepiness remains a critical component in on-road strategies for mitigating this risk. In order to take appropriate action when sleepy, drivers’ perceptions of their level of sleepiness must be accurate. \ud
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Aims: This study aimed to assess capacity to accurately identify sleepiness and self-regulate driving cessation during a validated driving simulator task. Participants: Participants comprised 26 young adult drivers (20-28 years). The drivers had open licenses but no other exclusion criteria where used. \ud
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Methods: Participants woke at 5am, and took part in a laboratory-based hazard perception driving simulation, either at mid-morning or mid-afternoon. Established physiological measures (including EEG) and subjective measures (sleepiness ratings) previously found sensitive to changes in sleepiness levels were utilised. Participants were instructed to ‘drive’ until they believed that sleepiness had impaired their ability to drive safely. They were then offered a nap opportunity. \ud
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Results: The mean duration of the drive before cessation was 39 minutes (±18 minutes). Almost all (23/26) of the participants then achieved sleep during the nap opportunity. These data suggest that the participants’ perceptions of sleepiness were specific. However, EEG data from a number of participants suggested very high levels of sleepiness prior to driving cessation, suggesting poor sensitivity. \ud
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Conclusions: Participants reported high levels of sleepiness while driving after very moderate sleep restriction. They were able to identify increasing sleepiness during the test period, could decide to cease driving and in most cases were sufficiently sleepy to achieve sleep during the daytime session. However, the levels of sleepiness achieved prior to driving cessation suggest poor accuracy in self-perception and regulation. This presents practical issues for the implementation of fatigue and sleep-related strategies to improve driver safety
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe 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
Sleepy driving and drink driving: attitudes, behaviours, and perceived legitimacy of enforcement of younger and older drivers
No full textSleepy driving and drink driving are two risky driving behaviours that substantially contribute to road crashes. Several studies demonstrate equivalent levels of impairment from both sleepy and drink driving. Yet, drivers perceive sleepy and drink driving distinctly different, with younger and older drivers engaging in these two risky driving behaviours at different rates. The current study sought to examine the sleepy and drink driving behaviours and perceptions in a sample of 114 younger (17-29 years) and 177 older (30+ years) drivers. Compared to older drivers, younger drivers reported more positive attitudes toward sleepy and drink driving behaviours, as well as more negative views regarding perceived legitimacy of sleepy driving enforcement. Younger drivers were also more likely to report performing sleepy driving behaviours than older drivers. Younger drivers reported greater likelihood to drive while sleepy, lower perceptions of legitimacy for sleepy driving, and more positive attitudes towards sleepy driving when compared to drink driving and the same pattern was found for older drivers as well. Subsequently, the self-reported likelihood of driving while sleepy was greater than drink driving in both age groups. Overall, the results suggest that sleepy driving is not viewed as equally dangerous as drink driving with younger drivers’ perceptions being more lenient than older drivers’ perceptions. It is likely that change is needed regarding the perceptions of dangerousness of sleepy driving with a particular focus on younger drivers seemingly needed
Variations on the Author
Full text link“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
Full text linkWe 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
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