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41.
Abstract

In this paper, the latent stochastic frontier model is used to estimate the technical efficiency of UK airports. These airports are ranked according to their technical efficiency for the period 2000–06 and the airports are disentangled and segmented by the cost frontier model, which leads us to advise the implementation of policies by segments. Economic implications arising from the study are also considered.  相似文献   
42.
Road restraint systems are roadside structures that include safety barriers, crash cushions, terminal of barriers, the transitions among different road restraint systems, motorcyclist protection devices, etc. These systems are used to protect vehicle occupants from dangerous roadside elements and are a key issue in roadside safety.  相似文献   
43.
This paper describes an approach developed to identify common elements of city performance that have transferability potential across a number of cities. The findings provide a wealth of information sourced from 200 measures in 19 European cities. A transferability framework is proposed, that uses ideas from traditional top-down approaches using city clustering to infer the transferability of measures, as well as elements of a bottom-up approach, based on the concept of “measure enabling context”. Systems' thinking diagramming was used to depict relationships between measures, drivers and barriers, portraying the feedbacks at work and the cause-effect relationships, to establish appealing preconditions for transferability.  相似文献   
44.
The objective of this work is to formulate a structure of procedures to support projects to integrate neighborhoods in the area of influence of railway corridors and the urban facilities around each station. Based on the concept of centrality, formulated mathematically by graph theory and with the support of a geographic information system (GIS), we propose interventions aiming to create a more harmonious urban environment better in tune with sustainable mobility. We highlight the relevance of quantitative approaches in the study of urban concepts to foster integration between transportation and urban development, as well as the potential of their application in various Brazilian metropolises having commuter rail systems that are currently underutilized and in the process of revitalization.  相似文献   
45.
This paper describes an analytic aggregation procedure for disaggregate demand models similar to the one proposed in earlier publications by Westin (1974) and McFadden and Reid (1975). The technique, which uses a multivariate normal approximation for the distribution of the vector of attributes, is based on the multinomial profit algorithm proposed by Daganzo, Bouthelier and Sheffi (1977) and can be applied to an arbitrary number of alternatives. The procedure is computationally so efficient that it enables us to calibrate disaggregate models with aggregate data by maximum likelihood using the same or slightly modified codes developed for disaggregated data. The paper also contains a small scale numerical example intended to illustrate the important highlights of the aggregation-estimation problem.  相似文献   
46.
The ability of bacteria to assimilate sulfur from dimethylsulfoniopropionate (DMSP) was examined in the western Arctic Ocean by combining microautoradiography and fluorescence in situ hybridization (FISH). Assimilation of leucine was also measured for comparative purposes since leucine is considered a universal substrate for bacteria, which use it for protein synthesis. Samples were collected at 3 m depth, through a hole in the ice, in the CASES (Canadian Arctic Shelf Ecosystem Study) overwintering station in Franklin Bay (eastern Beaufort Sea) in March and May 2004 to compare two contrasting situations: winter and early spring. FISH counts indicated that the bacterial assemblage consisted of α- (up to 60% of the EUB positive cells), β- (up to 10%) and γ-proteobacteria (around 20%), and Bacteroidetes (up to 60%). The β-proteobacteria were not active with any of the two substrates tested. The remaining groups were much less efficient at assimilating DMSP-sulfur (5% of the cells) than leucine (20–35%) both in winter and in spring. Only the Roseobacter group of α-proteobacteria showed a similar assimilation of both substrates.  相似文献   
47.
稳定可靠的蒸发器是纸厂平稳运行的基石,随着设备呈大型化趋势,正确考虑设计和安装蒸发系统很有必要  相似文献   
48.
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   
49.
The object of this paper is to explain how the expected length of traveling salesman tours changes with zone shape. To do this, a simple strategy that yields good traveling salesman tours is presented. The resulting tours are suboptimal but appear to be close to those that can be obtained by hand. Thus, the formulas that are provided may also be indicative of the length of tours built with better strategies. The results of this paper are useful for the design of distribution systems.  相似文献   
50.
Transportation - The inaccuracy of traffic forecasts has long stood as a central research theme in the field of infrastructure and transportation studies. The literature presents several motives...  相似文献   
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