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Abstract The increasing capacity of technological tools, as well as the advent of geographic information systems, has multiplied the ability to process large sets of microdata. At the same time, modeling concerns and the quest for a more in-depth understanding of individual behaviors is requiring more, and better, data. The gap between scientific modeling and informational tools for decision-making seems to be widening. In the Greater Montreal area, large sets of microdata have been available for more than 30 years. Along with the development of modeling and planning tools, particular attention has been given to the continuous enlightening of planners and decision-makers with respect to the outcomes of the various surveys. This has led to the development of particular interactive tools, specifically addressed at local planners, which present the most significant information regarding travel and demography, for geopolitically relevant areas. This paper presents the most recent interactive tool that has been developed for local planners in the Montreal area. It integrates information from both the most recent travel survey held in the region and the Canadian census. It offers both ease of use and relevant analytical means to assist in exploring the complex relations between spatial locations, demographic features, and activity-travel indicators. 相似文献
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A cooperative waiting strategy based on elliptical areas for the Dynamic Pickup and Delivery Problem with Time Windows 下载免费PDF全文
The purpose of this paper to present a cooperative scheduling algorithm for solving the Dynamic Pickup and Delivery Problem with Time Windows (DPDPTW). The idea behind cooperative waiting strategies is to calculate simultaneously the waiting times for all nodes in the solution. Classical non‐cooperative scheduling algorithms perform the scheduling for each route independently of the scheduling of the other routes. We present the Cooperative Scheduling Problem (CSP) based on the elliptical areas generated by vehicles waiting at their nodes. The CSP is solved by means of a genetic algorithm and is evaluated by using a set of benchmarks based on real‐life data found in the literature. Initially, two waiting strategies are presented: Wait‐Early‐Time scheduling and Balanced‐Departure scheduling. Extensive empirical simulations have been carried out by analyzing the degree of dynamism and the average waiting time, a new concept defined to take into account the gap between the time windows of pickup and delivery nodes. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
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Tolls have increasingly become a common mechanism to fund road projects in recent decades. Therefore, improving knowledge of demand behavior constitutes a key aspect for stakeholders dealing with the management of toll roads. However, the literature concerning demand elasticity estimates for interurban toll roads is still limited due to their relatively scarce number in the international context. Furthermore, existing research has left some aspects to be investigated, among others, the choice of GDP as the most common socioeconomic variable to explain traffic growth over time. This paper intends to determine the variables that better explain the evolution of light vehicle demand in toll roads throughout the years. To that end, we establish a dynamic panel data methodology aimed at identifying the key socioeconomic variables explaining changes in light vehicle demand over time. The results show that, despite some usefulness, GDP does not constitute the most appropriate explanatory variable, while other parameters such as employment or GDP per capita lead to more stable and consistent results. The methodology is applied to Spanish toll roads for the 1990–2011 period, which constitutes a very interesting case on variations in toll road use, as road demand has experienced a significant decrease since the beginning of the economic crisis in 2008. 相似文献
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María Feo-Valero Leandro García-Menéndez Salvador del Saz-Salazar 《Transportation》2016,43(1):101-122
This paper analyses the choice between road and rail in Spain where rail market share for freight is still residual. Discrete choice models are estimated with data obtained through a two-phase fieldwork, thus allowing us to carry out a stated preference efficient design for each interviewee. We analyse the existence of attribute cut-offs and the presence of a segment of the population with a zero value of frequency. Our results show that ignoring the existence of cut-offs and segments of the population with polarised valuations can lead to erroneous conclusions in terms of the possibilities of rail for absorbing significant quota. 相似文献
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Transportation - Inadequate infrastructure is recognized as an important barrier to cycling; therefore, improvements in the provision of bicycle facilities, such as bikeways, are frequently... 相似文献
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Thomas Degré 《WMU Journal of Maritime Affairs》2007,6(1):37-49
The Paris Memorandum of Understanding (Paris MoU) has defined criteria aimed at better targeting of ships for Port State Control
inspections. These criteria are mostly based on ship detentions or deficiencies. Another approach proposed in this paper is
based on the concept of risk, combining in various ways the probability of the occurrence of casualties and the potential
consequences of such occurrences. These measures are to help identify High Risk Vessels (HRV) and to inspect them accordingly. 相似文献
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R. Brémond 《Recherche - Transports - Sécurité》2012,28(3-4):248-255
As a result of some of the analogies between biology and transport, including the concepts of evolution and selection, we are wondering whether some ideas and methods used in biology may not be used to provide research avenues within the field of transportation. We are interested in the idea of complexity, which is common to the two scientific fields, but not treated in the same way by either of the two disciplines. By observing the way in which systemic biology has developed, from a largely “data-driven” approach to research guided by data, we are questioning whether such a direction would be possible in the field of transportation. This investigation also leads us to ask questions about “modules”, or the boundaries of the subsystems studied in the field of transportation, through the observation that molecular biology defines these boundaries in terms of the function of the subsystems. In conclusion, we are expressing the notion that these comparisons will lead to new research avenues in the field of transportation. 相似文献
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Zina Armi Elbahri Trabelsi Souad Turki Béchir Béjaoui Naceur Ben Maïz 《Journal of Marine Science and Technology》2010,15(4):417-426
Phytoplankton community structure was investigated in a 1-year study period from January to December 2006 in the Tunis North
Lagoon (South Mediterranean). Twice a month, sampling was carried out from the whole water column. Phytoplankton species composition
showed seasonal dynamics following the general environmental variable trends in the study area, with variation in species
abundance levels within each season characterised by the presence of different phytoplankton communities. Analysis of environmental
variables indicated that phytoplankton-dominant communities were associated with various water physicochemical characteristics,
especially water temperature and salinity. Accordingly, significant correlation was recorded between water temperature and
dinoflagellates (r = 0.35; p < 0.05) in summer and diatoms (r = 0.69; p < 0.05) in autumn, whereas euglenophytes, cyanophytes and chlorophytes were slightly correlated with temperature in autumn.
Salinity was positively correlated with dichtyophytes (r = 0.41; p < 0.05) in winter and with diatoms (r = 0.65; p < 0.05) and euglenophytes (r = 0.57; p < 0.05) in autumn. On the other hand, relationships between high nitrogen nutrient concentration and phytoplankton concentration
were recorded for diatoms (r = 0.43; p < 0.05 with NO2; r = 0.49; p < 0.05 with NO3) in winter. Silicate concentration supported proliferation of diatoms (r = 0.58; p < 0.05) in autumn in our study period. In contrast, increase of dinoflagellate concentration was associated with the decrease
of these parameters in spring and summer. 相似文献