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81.
王宇 《西安交通大学学报(英文版)》1995,(2)
ENHANCEDNITRICOXIDE(NO)-MEDIATEDVASODILATIONINLOWPOTASSIUMMEDIUMwagnYu;OS.Steinsland,SH.Nelson,AE.Feerick,WE.Johnstonn(Depart?.. 相似文献
82.
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
83.
84.
Lara Maria Erviti José Germán Giménez Asier Alonso 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》2017,55(12):1884-1908
The application of combined subspace identification methods to land vehicles would allow the modal parameters of the vehicle to be obtained, while it is in operation, thus improving the vehicle modal characterisation. However, when a land vehicle is circulating through a straight line, the excitations applied to the different axles are identical among them but with a certain time delay. The presence of repeated excitations with different time delays implies that the past and future subspaces include common vectors that may lead to problems in the application of the method. To analyse its influence, an index called the reduction coefficient resulting from excitations (RCE) has been defined. RCE evaluates the amount of information eliminated in the oblique projection due to the effect of repeated excitations. The use of RCE enables the selection of analysis parameters, particularly the sampling frequency, the signals grouping and some specific parameters of the subspace identification methods. 相似文献
85.
M.F. Yáñez S. Raveau J. de D. Ortúzar 《Transportation Research Part A: Policy and Practice》2010,44(9):744-753
Travel demand models typically use mainly objective modal attributes as explanatory variables. Nevertheless, it has been well known for many years that attitudes and perceptions also influence users’ behaviour. The use of hybrid discrete choice models constitutes a good alternative to incorporate the effect of subjective factors. We estimated hybrid models in a short-survey panel context for data among many alternatives. The paper analyses the results of applying these models to a real urban case study, and also proposes an approach to forecasting using these models. Our results show that hybrid models are clearly superior to even highly flexible traditional models that ignore the effect of subjective attitudes and perceptions. 相似文献
86.
Juan Carlos Martín Augusto Voltes-Dorta 《Transportation Research Part B: Methodological》2011,45(1):112-127
The econometric estimation of cost functions has been proposed in the literature as a suitable approach in order to obtain estimations of marginal costs, efficiency levels and scale elasticities for transport industries. However, regarding the airport industry, no significant attention has been paid in developing an airport-specific estimation methodology rather than adapting the procedures applied to other industries. The lack of comparable airport data is one of the causes which could explain the scarcity of this literature in the past, as well as the use of very limited approaches to explain airport technology. This paper tries to overcome these limitations by developing an airport-specific methodology to estimate a multi-output long-run cost function using an unbalanced pooled database on 161 airports worldwide. The specification of hedonically-adjusted aircraft operations, domestic and international passengers, cargo and commercial revenues in the output vector, as well as the calculation of input prices are discussed. Both technical and allocative inefficiencies are specified in the model using a Stochastic Frontier method that has been estimated through Bayesian Inference and Markov Chain Monte Carlo methods. 相似文献
87.
Alfred G. Cuzán 《Coastal management》2013,41(3):149-167
Abstract This is an exploration of the political economy of ports in the United States and Great Britain. A number of technical, economic, and political issues concerning ports are examined. Particular attention is paid to the institutional evolution of ports from private to public ownership, and its consequences for port efficiency. The paper concludes with a set of recommendations designed to reverse the trend toward port nationalization in both countries. 相似文献
88.
David A. Hensher Anne Yvrande‐Billon Rosário Macário John Preston Peter White Bill Tyson 《运输评论》2013,33(4):411-448
Abstract This paper documents some thoughts on the reform agenda in public transit that is occurring throughout the world. The specific focus is on a growing commitment to competitive regulation through competitive tendering, and the efforts by a few governments (notably in Australia) to take control of the tangible assets used by private operators as a mechanism to exercise the opportunity, if so taken, to put services out to competitive tender. The paper reviews the theoretical arguments and empirical evidence on contracting regimes and asset ownership, and the role that government and the operator might play in a setting in which building trusting and collaborative partnerships has merit in delivering services that are in the main funded from the public purse. 相似文献
89.
Julián Pando Andres Araujo Francisco Javier Maqueda 《Maritime Policy and Management》2013,40(2):67-87
Recent technological developments in maritime transport, particularly in container shipping and larger vessels, are having major repercussions at ports the world over. The latest wave of innovations has increased the level of competition in maritime transport, in particular in port activities. Shippers have many more alternatives available, something that tends to increase the hinterland of each port, precisely by reducing captive hinterlands. Ports are now generally moving towards formulas in which private initiative has a bigger role to play. Increases in competition combined with growth in private initiatives highlight the usefulness of marketing tools in two ways. Externally, because they help to achieve throughputs from remote points of origin and destination, and internally, by aiding the proper coordination of business and organizational activity at a commercial port. The present paper is a transversal study of the current situation of marketing and quality tools at major ports, including the opinions of a range of port commercial and marketing managers. We have also tried to describe the differentiated groups to be found at ports, as a useful methodology for identifying the nearest competition or ports with similar characteristics. 相似文献
90.
Juan M. Barragán Muñoz 《Coastal management》2013,41(3):137-156
The article is divided into three clearly defined sections. The first outlines the Brazilian National Coastal Zone Management Plan. The second offers a critical assessment of its introduction. To conclude, some general considerations are made. In this way, the author aims to achieve two objectives: to disseminate the aforementioned plan and offer a critical opinion of it. 相似文献