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Václav?PlevkaEmail authorView authors OrcID profile Pieter?Segaert Chris?M.?J.?Tampère Mia?Hubert 《Transportation》2016,43(6):979-996
This study investigates travel behavior determinants based on a multiday travel survey conducted in the region of Ghent, Belgium. Due to the limited data reliability of the data sample and the influence of outliers exerted on classical principal component analysis, robust principal component analysis (ROBPCA) is employed in order to reveal the explanatory variables responsible for most of the variability. Interpretation of the results is eased by utilizing ROSPCA. The application of ROSPCA reveals six distinct principal components where each is determined by a few variables. Among others, our results suggest a key role of variable categories such as journey purpose-related impedance and journey inherent constraints. Surprisingly, the variables associated with journey timing turn out to be less important. Finally, our findings reveal the critical role of outliers in travel behavior analysis. This suggests that a systematic understanding of how outliers contribute to observed mobility behavior patterns, as derived from travel surveys, is needed. In this regard, the proposed methods serve for processing raw data typically used in activity-based modelling. 相似文献
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Abstract Nationwide Transport Surveys and Time‐Use Surveys both reflect the daily agendas and schedules of the reporting individuals and should therefore yield comparable indicators of travel behaviour; for instance: immobility rate (share of persons not leaving the home on any one day), daily travel time, and number of trips per day. These two surveys exist in three countries from the same time period: Belgium, France, Great Britain. The comparisons demonstrate that they tell parallel stories, but that the levels of the variables are significantly different with lower immobility rates and longer travel times reported in the Time‐Use Surveys. These surveys should therefore be integrated in the analysis of travel behaviour analysis as a crucial yardstick. In Europe, where Nationwide Travel Surveys are intermittent and not harmonized, the harmonised Time‐Use Surveys allow for crucial European‐wide comparisions across time and space. 相似文献
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Silvana N.R. Birchenough Sin E. Boyd Roger A. Coggan David S. Limpenny William J. Meadows Hubert L. Rees 《Journal of Marine Systems》2006,62(3-4):204
This study presents the results of a trial assessment based on a combination of sampling techniques at a dredged material disposal site located off the North East coast of the UK, over 2001 to 2004. The site was surveyed with a high-resolution sidescan sonar system producing a mosaic with 100% coverage of the survey area. Benthic communities and sediments were ground-truthed using a Hamon grab with a video camera. Additionally, the area was also sampled in 2003 with a Sediment Profile Imaging (SPI) camera, which complemented other techniques by providing in situ information on sediment quality, and biogenic activities. An assessment is made of the benefits of combining the results from conventional methods, principally using grab samples, with those from acoustic techniques and optical imaging devices to determine seafloor and macrobenthic conditions. This information has the potential to contribute to the enhancement of routine monitoring programmes within UK waters. 相似文献
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A study of the influence of severe environmental conditions on common traffic congestion features 下载免费PDF全文
On the basis of real traffic and environmental data measured on German freeways, we studied common features of traffic congestion under the influence of severe weather conditions. We have found that traffic features [J] and [S] defining traffic phases “wide moving jam” (J) and “synchronized flow” (S) in Kerner's three‐phase theory are indeed common spatiotemporal traffic features. The quantitative parameters for both traffic phases [S] and [J] were investigated in a comparison of “ideal” weather conditions (good visibility and no precipitation) and severe weather situations (icy road, wind, precipitation, etc.). We showed spatiotemporal congested patterns in several space–time diagrams based on the Automatic Tracking of Moving Jams/Forecasting of Traffic Objects (ASDA/FOTO) model reconstruction for roadside detectors. A statistical study of traffic phase [J] parameters was presented, showing the average values and standard deviation of the quantities. Similarities and differences were analyzed, and some consequences for vehicular applications were discussed to cope with severe weather conditions. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
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