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71.
Stef Proost Fay DunkerleyBruno De Borger Astrid GühnemanPia Koskenoja Peter MackieSaskia Van der Loo 《Transportation Research Part A: Policy and Practice》2011,45(3):161-170
The trans-European transport network (TEN-T) encompasses the major planned transport infrastructure in Europe, ranging from high speed rail to port infrastructure. Projects in this category are considered priority projects and receive European subsidies; but these have been insufficient to get these projects off the ground. This paper addresses two research questions. First, it sketches the basic economics of cross-boundary infrastructure projects: what pricing and investment policies can we expect, what is the role of through traffic and high fixed costs of infrastructure? Second, it examines briefly what lessons the EU could draw from the experience of other existing federal funding institutions like the US and Germany. These ideas are used to propose a new subsidy scheme for the TEN-T projects. 相似文献
72.
Javier Alonso Vicente Milanés Joshué Pérez Enrique Onieva Carlos González Teresa de Pedro 《Transportation Research Part C: Emerging Technologies》2011,19(6):1095-1110
This article presents a cooperative manoeuvre among three dual mode cars – vehicles equipped with sensors and actuators, and that can be driven either manually or autonomously. One vehicle is driven autonomously and the other two are driven manually. The main objective is to test two decision algorithms for priority conflict resolution at intersections so that a vehicle autonomously driven can take their own decision about crossing an intersection mingling with manually driven cars without the need for infrastructure modifications. To do this, the system needs the position, speeds, and turning intentions of the rest of the cars involved in the manoeuvre. This information is acquired via communications, but other methods are also viable, such as artificial vision. The idea of the experiments was to adjust the speed of the manually driven vehicles to force a situation where all three vehicles arrive at an intersection at the same time. 相似文献
73.
Richard W. Stoffle Jessica Minnis Amanda Murphy Kathleen Van Vlack Nathan O'Meara Tavarrie Smith 《Coastal management》2013,41(5):501-517
This article recommends the parallel but separate modeling of nature-based and people-based marine protected areas (MPA) before the design and siting stages of establishing an MPA. Separate but simultaneous modeling of ideal nature and people MPAs permits each to be maximized for its own variables and subsequently compared to identify conflicts and agreements. The case that supports this recommendation is in the Commonwealth of the Bahamas, where the study conducted 572 interviews with people from six traditional settlements in the central Exumas Islands and Cays. The research is focused on why members of these settlements differentially responded to three nearby national MPA proposals. 相似文献
74.
ABSTRACTConventional travel time reliability assessment has evolved from road segments to the route level. However, a connection between origin and destination usually consists of multiple routes, thereby providing the option to choose. Having alternatives can compensate for the deterioration of a single route; therefore, this study assesses the reliability and quality of the aggregate of the route set of an origin-destination (OD) pair. This paper proposes two aggregation methods for analyzing the reliability of travel times on the OD level: 1) an adapted Logsum method and 2) a route choice model. The first method analyzes reliability from a network perspective and the second method is based on the reliability as perceived by a traveler choosing his route from the available alternatives. A case study using detailed data on actual travel times illustrates both methods and shows the impact of having variable departure times and the impact of information strategies on travel time reliability. 相似文献
75.
Silvia Fernndez Unai Villanueva Alberto de Diego Gorka Arana Juan Manuel Madariaga 《Journal of Marine Systems》2008,72(1-4):332
Deep water samples (in contact with the sediment) were collected at eight different points of the estuary of the Nerbioi-Ibaizabal River (Bay of Biscay, Basque Country), both at low and high tides, during four sampling campaigns (May, September and December 2005 and March 2006). Superficial water was also sampled in March 2006. Temperature, pH, redox potential, dissolved oxygen and electrical conductivity corresponding to each sample were measured in situ at each sampling point using a multiparametric probe. The physico-chemical parameters found are typical of highly stratified estuaries, with an acceptable oxygenation level. After filtering and acidifying the samples, they were analysed by inductively coupled plasma/mass spectrometry (ICP/MS) to simultaneously determine the total concentration of Al, As, Cr, Cu, Fe, Mn, Ni and Zn. Concentrations in the μg kg− 1 level were found in all cases (cCr and cNi, 1–10; cAl, cAs and cZn, 10–50; cCu and cMn, 10–100 and cFe, 100–400 μg kg− 1). A probable net input of Al, Cr, Mn and Zn via the main (Nerbioi-Ibaizabal) and some of the tributary rivers (Galindo, Asua and Gobela) was identified. Evidence of a common source of Al and Zn to the estuary was found. Correlation analysis of data revealed connections between variables (concentration of Cu, Fe and As with salinity, as well as cAl with cZn, cCu with cFe, cAs with cFe, and cAs with cCu). Principal Component Analysis (PCA) of data allowed the samples to be grouped according to sampling campaign, with two principal components accounting for 62% of the total variance. In addition, plots of element concentration against salinity suggested a conservative behaviour for As, Cu and Fe and a non-conservative one for Cr. Not clear mixing behaviour was observed for the rest of elements. 相似文献
76.
This paper explores a selection of recently proposed bootstrapping techniques to estimate non-parametric convex (DEA) cost frontiers and efficiency scores for transit firms. Using a sample of Norwegian bus operators, the key results can be summarized as follows: (i) the bias implied by uncorrected cost efficiency measures is numerically important (close to 25%), (ii) the bootstrapped-based test rejects the constant returns to scale hypothesis, and (iii) explaining patterns of efficiency scores using a two-stage bootstrapping approach detects only one significant covariate, in contrast to earlier results highlighting, e.g., the positive impact of high-powered contract types. Finally, comparing the average inefficiency obtained for the Norwegian data set with an analogous estimate for a smaller French sample illustrates how the estimated differences in average efficiency almost disappear once sample size differences are accounted for. 相似文献
77.
Kris De Baere Helen Verstraelen Lucien Lemmens Silvia Lenaerts Raf Dewil Yves Van Ingelgem Geert Potters 《Journal of Marine Science and Technology》2014,19(1):116-123
Sacrificial anodes have become a standard practice for the protection of ballast tanks of merchant vessels against corrosive damage. A well protected tank should extend the life span of a ship and consequently enhances its economic value. An in situ survey comprising more than 100 merchant vessels provided the opportunity to measure the impact of these anodes on the life expectancy of these vessels. Contrary to the general belief of these anodes’ beneficial effect, no significant difference was found in our observations in terms of corrosion occurrence between ship populations with and without sacrificial anodes, across all ship ages. This may be explained by the highly variable conditions and the complex geometry in a ballast tank severely impede optimal and straightforward installation of these anodes in these tanks. Also, poorly placed anodes in it may harm the integrity of the coating of the tank. We therefore plead for uniform and clear rules on anode installation and inspection. 相似文献
78.
Many decisions taken by mankind are rational only to a limited extent. This holds for individual travel behaviour, but also for long-range strategic decisions on transport systems or transport technology. In any decision problem, coping with uncertainty is the most critical element. The introduction of new transport technology is surrounded by uncertainty. For example, there is uncertainty about the pace and extent of adoption of new technology and there is uncertainty about the impact of new technology in terms of increased sustainability or increased efficiency. This article maps uncertainty surrounding new transport technology and identifies ways in which to deal with uncertainty in policy making. The findings will be illustrated with electric vehicles, particularly with two specific strategies to deal with uncertainty: interactive technology watching and experimentation in a market niche. The paper concludes with a discussion of success factors that influence the outcomes of such strategies. 相似文献
79.
Oscar van Vliet Bert de Vries André Faaij Wim Turkenburg Wander Jager 《Transportation Research Part D: Transport and Environment》2010,15(6):326-342
We have formalized and parameterized a model for the production of six transport fuels and six fuels blends from six feedstocks through 13 different production chains, and their adoption of by 11 distinct subpopulations of motorists. The motorists are represented by agents that use heuristics to choose a fuel on the basis of three attributes and a social feedback loop. Adoption of specific fuels is mostly driven by price differences, but other factors play a role if prices are similar. The results are not always intuitive and do not always show up immediately. We find that sustained combinations of interventions are required to bring about a transition away from petrol or diesel. Adoption of alternative fuels was most often confined to niche markets with a share of 5% or lower. Only in a single case was a complete fuel transition observed. 相似文献
80.
Mario Hoppema Eberhard Fahrbach Michel H. C. Stoll Hein J. W. de Baar 《Journal of Marine Systems》1999,19(4):1935
Data from two cruises, one in April/May 1996 and one in December/January 1993, covering the same wide area in the offshore Weddell Sea, were used to derive the annual extent of entrainment and the capacity of the biological pump. The former property was obtained with the help of dissolved oxygen data, whereas the latter was approximated with nutrients. Especially the data from April/May, representing the initial state of the winter surface layer, were crucial to assess the annual extent of these processes. The results were applied to our carbon dioxide data. The annual increase of the Total CO2 (TCO2) concentration in the surface layer due to vertical transport amounts to 16.3 μmol kg−1. An entrainment rate of deep water in the surface layer amounting to 35±10 m yr−1 was deduced. The compensating, biologically mediated TCO2 reduction was calculated to be larger than the TCO2 increase due to vertical transport. Since the balance of these two processes determines whether the Weddell Sea is a source or a sink of CO2, this indicates that the Weddell Sea, albeit upwelling area, is definitely a sink for atmospheric CO2 on an annual basis. This conclusion is further supported by contemplations that the biological drawdown of CO2 in the Weddell Sea as a whole is probably underestimated by our calculations. The new production for the Weddell Sea on a per unit area basis was found to be much higher than that for the Antarctic Ocean, when the latter value is being obtained by traditional biological methods. On the other hand, the CO2 uptake by the Weddell Sea on a per unit area basis is somewhat smaller than the CO2 uptake by the world ocean. 相似文献