85,188 research outputs found
The effects of increased workload on driving performance and visual behaviour
No full textThe workload of drivers has been increasing in modern times due to the growing use of In-Vehicle systems. The higher task demand resulting from these extra visual and auditorystimuli presents an increasingly challenging problem for drivers, and has become a growing safety concern, as the higher workloads can adversely affect driving performance and must be balanced against the benefits from in-vehicle systems. Existing models suggest that when the induced workload is relatively low, drivers can deal with this increased demand by using different coping strategies; however, when the workload increases above a certain level, drivers’ performance decreases. These models are relatively simplistic and do not describe the extent to which drivers’ coping strategies can impact on the relationship between workload and performance, which are difficult to observe by traditional measures. The literature suggests that visual behaviour or eye movements, with its physiological nature, combines attributes of both attention state and human behaviour, and can be used to provide sensitive, diagnostic, and instantaneous measurements to investigate the impact of increased workload on performance, and explore associated coping strategies. An on-road experiment was therefore conducted to observe drivers’ behaviour when their workload was increased by in-vehicle secondary tasks, and the impact this had on their performance, using eye movement as well as traditional vehicle control and manoeuvring measurements. The field experiment was run under two driving scenarios of Car-Following and Free-Driving, on two road sections in Hampshire over a period of three months, using the Transportation Research Group’s Instrumented Vehicle (IV) and a FaceLabTM eye monitoring system. An Operation Simulation System was developed for drivers to perform a series of in-vehicle auditory and visual tasks through touch screen and audio systems, which reflected two different types of workload (i.e. mental and visual), with three levels of difficulty. Surveys were also conducted during and after each test run to assess drivers’ workload perception and gain an understanding of their experiences of performing the tasks, and a database established to organise all the information collected to enable subsequent analyses to be conducted readily. The results show that drivers’ behaviour was significantly impacted by additional tasks, and their secondary task performance decreased steadily with task complexity. The effects were consistent across the two Scenarios, although driving performance generally deteriorated more for the visual tasks than auditory ones, which reflects the higher conflict of visual and manual resource caused by these tasks, and all drivers took action to compensate either by increasing their headways in Car-Following, or reducing their speed in Free-Driving. The effects were reflected in their visual behaviour, which showed higher blink rates and shrunk visual searching range for the auditory tasks, i.e. a higher mental workload over baseline driving, and higher saccade and more visual transactions between different objects for the visual ones. Differences were also found in the driving and visual behaviour of individual driver characteristics groups, including gender and different experience groups. While traditional performance measurements showed many differences in behaviour due to the extra in-vehicle tasks, the different coping strategies adopted by drivers were typically observed only through the analysis of their visual behaviour. The use of these additional measurements provides an improvement to existing models for describing the relationship between workload and performance in dual-tasking
Measurement of the differential and double-differential Drell-Yan cross sections in proton-proton collisions at root s=7 TeV
No full textMeasurements of the differential and double-differential Drell-Yan cross sections are presented using an integrated luminosity of 4.5 (4.8) fb−1 in the dimuon (dielectron) channel of proton-proton collision data recorded with the CMS detector at the LHC at s√ = 7 TeV. The measured inclusive cross section in the Z-peak region (60–120 GeV) is σ(ℓℓ) = 986.4 ± 0.6 (stat.) ± 5.9 (exp. syst.) ± 21.7 (th. syst.) ± 21.7 (lum.) pb for the combination of the dimuon and dielectron channels. Differential cross sections dσ/dm for the dimuon, dielectron, and combined channels are measured in the mass range 15 to 1500 GeV and corrected to the full phase space. Results are also presented for the measurement of the double-differential cross section d2σ/dm d|y| in the dimuon channel over the mass range 20 to 1500 GeV and absolute dimuon rapidity from 0 to 2.4. These measurements are compared to the predictions of perturbative QCD calculations at next-to-leading and next-to-next-to-leading orders using various sets of parton distribution functions
Mileewa triloba He, Yan & Yang 2021
No full text49. Mileewa triloba He, Yan & Yang, 2021 Mileewa triloba He, Yan & Yang, 2021: 444. Type-locality. China (Hainan). Distribution. China (Hainan).Published as part of He, Hong-Li, Yan, Bin, Yang, Mao-Fa & Webb, M. D., 2021, Four new species of Mileewini leafhoppers (Hemiptera: Cicadellidae: Mileewinae) from China, with a checklist to Chinese species, pp. 521-540 in Zootaxa 4949 (3) on page 536, DOI: 10.11646/zootaxa.4949.3.5, http://zenodo.org/record/464062
Ujna cavipenis He, Yan & Yang 2021
No full text1. Ujna cavipenis He, Yan & Yang, 2021 Ujna cavipenis He, Yan & Yang, 2021: 446. Type-locality. China (Hainan). Distribution. China (Hainan).Published as part of He, Hong-Li, Yan, Bin, Yang, Mao-Fa & Webb, M. D., 2021, Four new species of Mileewini leafhoppers (Hemiptera: Cicadellidae: Mileewinae) from China, with a checklist to Chinese species, pp. 521-540 in Zootaxa 4949 (3) on page 538, DOI: 10.11646/zootaxa.4949.3.5, http://zenodo.org/record/464062
Using performance assessment in secondary school mathematics: an empirical study in a Singapore classroom
No full textThis article reports an exploratory study on using performance assessment in mathematics instruction in a high-performing secondary school in Singapore. An intact mathematics class participated in the study, and received chapter-based performance tasks as intervention during regular mathematics lessons for about one and a half school years. The performance tasks used included authentic and/or open-ended tasks. The students’ academic achievements and attitudes in mathematics were compared with a comparison class that did not receive the intervention. Both quantitative and qualitative data were collected, mainly through questionnaire surveys, performance task tests, conventional school exams, and interviews with students and teachers. The results suggest that the students receiving the intervention performed significantly better than their counterparts in solving conventional exam problems, and in general they also showed more positive changes in attitudes towards mathematics and mathematics learning. The students from the experimental class also expressed positive views about the benefits of using performance tasks in promoting their ability in higher order thinking, though no statistically significant difference was detected between the two classes of students in solving unconventional tasks before and after intervention. Overall, the results appear to support teachers’ using contextualised problems in real life situations and open-ended investigations in students’ learning of mathematic
Sivers effect in Drell-Yan processes
No full textThe Sivers distributions recently extracted from semi-inclusive deep inelastic scattering data [M. Anselmino, Eur. Phys. J. A 39, 89 (2009)] are used to compute estimates for Sivers asymmetries in Drell-Yan processes which are being planned at several facilities (RHIC, COMPASS, J-PARC, PAX, PANDA, NICA (JINR) and SPASCHARM (IHEP)). Most of these asymmetries turn out to be large and could allow a clear test of the predicted sign change of the Sivers distributions when active in SIDIS and Drell-Yan processes. This is regarded as a fundamental test of our understanding, within QCD and the factorization scheme, of single spin asymmetries
Drell Yan processes at LHC
No full textWe study the main observables associated with the Drell-Yan processes at the LHC
Why hedge? Extent, nature, and determinants of derivative usage in U.S. municipalities
No full textUsing a hand-collected dataset of over 300 observations of large U.S. cities and counties, this paper investigates the extent, nature and determinants of derivatives usage in the municipal sector.Over half of our sample entities engage in derivative transactions and a vast majority of these transactions are intended to manage interest rate risk. Swaps, by far, are the most popular derivative instrument. In terms of the determinants of derivative usage,we find that the propensity to use derivatives as well as the extent of derivative usage is higher for municipalities that are larger and more financially constrained. We do not find growth to be related to municipal derivative usage. Contrary to suggestions made in the popular press, we fail to find managerial opportunism to be a significant factor in municipal derivative usage. We also find that more sophisticated managers of large municipalities and less sophisticated managers of small municipalities are more likely to engage in derivative transactions.Peer reviewe
A study on the reliability of consecutive k-Out-of-n: G systems based on Copula
No full textThe computation of reliability characteristics of a system that consists of dependent components is sometimes difficult especially when the type of dependence is not known. This article introduces the copula method to calculate the reliability of dependent consecutive k-out-of-n: G systems. The components in these systems are dependent on each other and the dependency may be either linear or nonlinear. The copula is a popular tool for modeling the dependence structure of data. It contains the information about the dependency structure of a vector of random variables and can capture nonlinear dependence. Based on the copula theory, the article analyzes the consecutive k-out-of-n: G systems and gets the reliability indexes. Finally, some numerical examples are presented to illustrate the results obtained in this article.Peer reviewe
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