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51.
Daniel S. Zachary Jessica Gervais Ulrich Leopold 《Transportation Research Part D: Transport and Environment》2010,15(2):82-93
This paper describes a multi-indicator assessment and minimization problem focused on aviation “Community” noise. The model explores a combined noise and emission objective for airfreight movements at Luxembourg’s Findel Airport. Community noise is evaluated via four population impact indicators emissions are tabulated from in-flight segments in the proximity of the airport and from the contribution of taxiing. A set of scenarios based on trajectory, aircraft scheduling, fleet composition, operational procedures are implemented in software. An integer programming methodology is used to search for minimal environmental impact. An on/off switch allows for an evaluation of each indicator in the objective. Different impacts on the population are explored in a case study involving the Cargolux Airlines International S.A. 相似文献
52.
Public transport improvements may increase economic productivity if they enable the growth and densification of cities, downtowns, or industrial clusters and thereby increase external agglomeration economies. It has been argued that the potential agglomeration benefits are large; if so, understanding them better would be useful in making funding decisions about public transport improvements. We reviewed theoretical and empirical literature on agglomeration as well as a small number of articles on transportation's role in agglomeration. The theoretical literature is useful in understanding possible avenues by which transportation improvements might affect agglomeration, although there is little discussion of public transport specifically. Relevant empirical studies tend to focus on metropolitan regions and use a generalized measure of transportation cost. But public transport impacts on agglomeration are likely to be different from road investment impacts. We identified several ways of conducting research building on this literature that would help evaluate the agglomeration impacts of public transport proposals: tracing the links between transport, agglomeration, and productivity; better motivating research using theories of agglomeration mechanisms; taking scale and redistribution into account; exploring the functional form of agglomeration economies; accounting for endogeneity in model structure; and considering development context. 相似文献
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54.
Use of SeaWiFS data for light availability and parameter estimation of a phytoplankton production model of the Bay of Biscay 总被引:2,自引:0,他引:2
Martin Huret Francis Gohin Daniel Delmas Michel Lunven Vronique Garon 《Journal of Marine Systems》2007,65(1-4):509
Processing SeaWiFS (Sea-viewing Wide Field-of-view Sensor) data provides useful information for the observation and modelling of the phytoplankton production of the Bay of Biscay. Empirical algorithms allow the retrieval of chlorophyll a and non-living Suspended Particulate Matter (SPM) concentrations. These data are used to constrain a coupled 3D physical–biogeochemical model of the Bay of Biscay continental shelf. Two issues are investigated, depending on the variable used, to constrain the winter to spring phytoplankton production for the year 2001. First, SPM data is used as forcing data to correct the corresponding state variable of our model. This allows the realistic simulation of the light limited bloom at the end of February 2001, as observed with SeaWiFS chlorophyll a images and from the NUTRIGAS field cruise. Second, chlorophyll a data is used for parameter estimation of the biogeochemical model. The ability of assimilating these data is tested to improve the simulation of strong blooms observed in late May 2001 in the Loire and Gironde plumes. A global optimization method (Evolutive Strategies) is adapted to the complete 3-D coupled model, in order to find the best set of parameters. The hydrological conditions during the bloom can be validated with data from the PEL01 field cruise. After selection of the most sensitive parameters, the method is tested with twin experiments. Then, the use of real SeaWiFS data reduces the model/data misfit by a factor of two, improving the simulation of bloom intensities and extensions. The sets of parameters retrieved in each plume are discussed. 相似文献
55.
Daniel Salmons 《天津汽车》2008,(5):26
尽管这些年来汽车照明技术取得不小的进步,但夜间行车的风险仍比白天大得多.据美国国家公路交通安全管理局(NHTSA)的统计,虽然夜间行车在整个公路交通中只占1/4,发生的死亡事故却占了一半. 相似文献
56.
Audrey de Nazelle Daniel A. Rodríguez 《Transportation Research Part D: Transport and Environment》2009,14(4):255-263
A microsimulation of individuals’ activities is used in the context of a risk analysis framework to assess the impacts of hypothesized changes to the built environment on personal energy expenditure and on inhalation of air pollutants. Uncertainty is assessed using Monte Carlo simulations and sensitivity analyzes. We find both simulated individuals that augment and others that reduce their energy expenditure and inhalation dose of pollutants, with median increases displaying larger magnitudes than the decreases. Up to 75% of the population has significant increases in energy expenditure and pollutant inhalation. We also find, however, high uncertainty associated with the estimates. Results differ considerably depending on the travel mode choice model used in the simulation. 相似文献
57.
Ye Tian Sheng Liu William J.T. Daniel Paul A. Meehan 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》2015,53(5):692-709
This paper presents the locomotive traction controller performance with respect to the track wear under different operation conditions. In particular, an investigation into the dynamic response of a locomotive under changing wheel–rail friction conditions is performed with an aim to determine the effect of controller setting on track wear. Simulation using a full-scale longitudinal–vertical locomotive dynamic model shows that the appropriately designed creep threshold, controller, settings can effectively maintain a high tractive effort while avoiding excessive rail damage due to wear, especially during acceleration under low speed. 相似文献
58.
Daniel A. Rodríguez Carlos H. Mojica 《Transportation Research Part A: Policy and Practice》2009,43(5):560-571
A before and after hedonic model is used to determine the property value impacts on properties already served by the transit system caused by extensions to Bogotá’s bus rapid transit system. Asking prices of residential properties belonging to an intervention area (N = 1407 before, 1570 after) or a control area (N = 267 before, 732 after) and offered for sale between 2001 and 2006 are used to determine capitalization of the enhanced regional access provided by the extension. Properties offered during the year the extension was inaugurated and in subsequent years have asking prices that are between 13% and 14% higher than prices for properties in the control area, after adjusting for structural, neighborhood and regional accessibility characteristics of each property. Furthermore, the appreciation is similar for properties within 500 m and properties between 500 m and 1 km of the BRT. 相似文献
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60.
Daniel Lancien 《先进运输杂志》1993,27(1):65-77
The development of railway transportation, especially through the gradual implementation of high-speed European network, is inciting railway companies to design railway movements command and control systems to enhance technical performance in terms of throughput and control of disturbances while simultaneously minimizing operational costs. The new command-control systems must be modular, adaptable and evolutive structures from both functional and geographical viewpoints if they are to satisfy all operational needs. Concurrent research into performance enhancement and cost reduction prescribes a system in which the majority of the “real time” components are aboards the locomotives. This is particularly true for those components used by the train to indicate its own position on the network as well as those enabling it to converse with operational control centers. The initial task is to design a global architecture of the command-control system that satisfies modularity and availability criteria followed by the development of numerous technical components including radar self-location systems and cellular radio transmission networks. The French (SNCF) and German (DB) national railways have implemented a vast program of co-operation aimed at providing valid, proven answers to these problems so as to allow their trains to travel freely on either network. 相似文献