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Rangel Thais Gonzalez Juan Nicolas Gomez Juan Romero Fernando Vassallo Jose Manuel 《Transportation》2022,49(2):373-393
Transportation - Ride-hailing is an emerging service that is transforming door to door mobility in urban areas. Users can easily request a ride through a smartphone app that informs them of the... 相似文献
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The present paper proposes a conceptual framework for the driver’s visual–spatial perceptual processes. Based on a theoretical analysis of driving proposed by Gibson and Crooks [(1938). A theoretical field-analysis of automobile-driving. The American Journal of Psychology, 51, 453–471. doi:10.2307/1416145], the developed field of safe travel (FoST) framework suggests that at any moment the driver constructs a “field” by integrating two perceptual entities: (i) the possible available spatial fields for locomotion and (ii) the driver’s mental image of ego-vehicle outer-line and motion dynamics. This framework is used to reinterpret in a unified way a number of disparate research findings reported in the literature concerning specific driving sub-tasks (e.g. lane keeping and car following). It is argued that the FoST framework may be used to predict drivers’ behaviour in various traffic/situation environments based on their prioritisation between the above two perceptual entities. Implications of the proposed framework at a theoretical and practical level, in view of the future of driving with multiple levels of automation, are also discussed. 相似文献
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Franois G. Schmitt Yongxiang Huang Zhiming Lu Yulu Liu Nicolas Fernandez 《Journal of Marine Systems》2009,77(4):473
We consider here surf zone turbulence measurements, recorded in the Eastern English Channel using a sonic anemometer. In order to characterize the intermittent properties of their fluctuations at many time scales, we analyze the experimental time series using the Empirical Mode Decomposition (EMD) method. The series is decomposed into a sum of modes, each one narrow-banded, and we show that some modes are associated with the energy containing wave breaking scales, and other modes are associated with small-scale intermittent fluctuations. We use the EMD approach in association with a newly developed method based on Hilbert spectral analysis, representing the probability density function in an amplitude–frequency space. We then characterize the fluctuations in a stochastic framework using a cumulant generating function for all scales, and compare the results obtained from direct and classical structure function analysis, to EMD–Hilbert spectral analysis results, showing that the former method saturates at large scales, whereas the latter method is more precise in its scale approach. These results show the strength of the new EMD–Hilbert spectral analysis method for data presenting a strong forcing such as found in shallow water, wave dominated situations. 相似文献
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Marie-France Joly Jean-Pierre Thouez Robert Bourbeau Yves Bussire Andr Rannou 《先进运输杂志》1992,26(1):61-77
In this study we analyze the dmographic and geographical distribution of pedestrian accidents (n=28,452) in the Quebec Municipalités régionales de comté (MRC) reported between January 1, 1983 and December 31, 1988. In order to be able to make comparisons between MRCs, we have created in Comparative Mortality Index and a Comparative Morbidity Index. We use a logistic regression model to single out explanatory factors. The main tendencies which are apparent in the demographic analysis are an overrepresentation of young persons and elderly persons in the accident statistics, and that men are more at risk than women. Men 15 years and under and men 65 years and over are more at risk of being involved in a fatal pedestrian accident. The geographic analysis show that among men, the average mortality rate is one and a half times greater in rural MRCs than in urban MRCs; among women, rural mortality is two and a half times greater than urban mortality. In the case of non-severe injuries we note an over-representation of urban MRCs. Young persons 15 years or less who live in an urban, populated zone are those most at risk of being involved in a pedestrian accident. Identifying high risk groups or areas is a prerequisite step for injury prevention and control. 相似文献
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An important part of the French research program on cavitation erosion, conducted from 1980 to 1995, was devoted to pitting.
Histograms of pit size have been extensively used to characterise the hydrodynamic aggressiveness of a cavitating flow. Numerous
erosion tests, limited to the incubation period, were carried out on similar test sections, for different velocities, liquids,
length scales, and materials. Scaling laws were discussed and two kinds of methods for prediction of the erosion rate were
proposed. The first one is based upon the estimation of the aggressiveness of the prototype cavitating flow, from pitting
tests on a model and the simulation of the prototype histogram of pits on an appropriate device. The second one is based upon
a correlation between the advanced stage of erosion and the incubation period, consisting of a proper adimensionalization
of the mass-loss curve. After several years of research and the development of special facilities, devices and techniques,
more deterministic procedures for predicting cavitation erosion could now be developed, based not upon erosion tests, but
upon the characterization of the aggressiveness of the cavitating flow in terms of impact loads and the analysis of the mechanical
and metallurgical response of the material to successive impacts. 相似文献
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Since the 1990s, transport project assessments take systematically pollutant emission estimations into account. This paper is about the methodological aspects of these calculations. It focuses more specifically on the car fleet hypothesis, which most often lays on national data, without consideration of local specificities. We use the last household travel survey from Lyon, 2006, and the SIMBAD model to compare the results of CO2 and NOx emissions estimated from the French national car fleet, the aggregated Lyon car fleet and the same fleet disaggregated by household location and income. We show that the error level varies, depending on the pollutant and the observation scale. The use of an aggregated local car fleet seems interesting and satisfactory for a global emission assessment. If the results are required at a more detailed spatial level, the use of this local fleet improves sharply the estimations in comparison of a national fleet; the fleet disaggregation refines the results for NOx. 相似文献
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Hassane Saghir Marc Heddebaut Fouzia Elbahhar Jean-Michel Rouvaen Atika Menhaj-Rivenq Jean-Pierre Ghys 《Transportation Research Part C: Emerging Technologies》2009,17(1):81-97
The capabilities of ultra-wide-band (UWB) technology make it a viable candidate for fourth generation wireless communication. This paper proposes the use of UWB radio technology and time-reversal (TR) technique for underground train-to-wayside communication systems. UWB technology has the potential to offer simultaneous ground-to-train communication, train location and obstacle detection in front of the trains. Time-reversal channel prefiltering facilitates signal detection and helps reducing interference. Thus, UWB–TR combination provides a challenging, economically sensible, as well as technically effective alternative solution to existing signaling technologies used in urban transport systems. This paper concentrates on the communication function and reports simulation and measurement performance evaluation of such combinations, respectively in a deterministic tunnel channel model and in real tunnel environments. A new approach is also proposed to ensure multiple access (MA) communication using modified-orthogonal waveforms. 相似文献
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2006年的世界高速铁路 总被引:2,自引:0,他引:2
介绍了亚洲、欧洲等国家高速铁路及其新线建设情况,简述了这些国家和地区的高速铁路发展意向,指出高速铁路光明的发展前景. 相似文献