Approximating Airports and Railways

In this paper we consider the airport and railway problem (AR), which combines capacitated facility location with network design, both in the general metric and the two-dimensional Euclidean space. An instance of the airport and railway problem consists of a set of points in the corresponding metric, together with a non-negative weight for each point, and a parameter k. The points represent cities, the weights denote costs of opening an airport in the corresponding city, and the parameter k is a maximum capacity of an airport. The goal is to construct a minimum cost network of airports and railways connecting all the cities, where railways correspond to edges connecting pairs of points, and the cost of a railway is equal to the distance between the corresponding points. The network is partitioned into components, where each component contains an open airport, and spans at most k cities. For the Euclidean case, any points in the plane can be used as Steiner vertices of the network. We obtain the first bicriteria approximation algorithm for AR for the general metric case, which yields a 4-approximate solution with a resource augmentation of the airport capacity k by a factor of 2. More generally, for any parameter 0 < p <= 1 where pk is an integer we develop a (4/3)(2 + 1/p)-approximation algorithm for metric AR with a resource augmentation by a factor of 1 + p. Furthermore, we obtain the first constant factor approximation algorithm that does not resort to resource augmentation for AR in the Euclidean plane. Additionally, for the Euclidean setting we provide a quasi-polynomial time approximation scheme for the same problem with a resource augmentation by a factor of 1 + mu on the airport capacity, for any fixed mu > 0

Approximating actual flows in physical infrastructure networks : the case of the Yangtze River Delta high-speed railway network

Previous empirical research on urban networks has used data on infrastructure networks to guesstimate actual inter-city flows. However, with the exception of recent research on airline networks in the context of the world city literature, relatively limited attention has been paid to the degree to which the outline of these infrastructure networks reflects the actual flows they undergird. This study presents a method to improve our estimation of urban interaction in and through infrastructure networks by focusing on the example of passenger railways, which is arguably a key potential data source in research on urban networks in metropolitan regions. We first review common biases when using infrastructure networks to approximate actual inter-city flows, after which we present an alternative approach that draws on research on operational train scheduling. This research has shown that 'dwell time' at train stations reflects the length of the alighting and boarding process, and we use this insight to estimate actual interaction through the application of a bimodal network projection function. We apply our method to the high-speed railway (HSR) network within the Yangtze River Delta (YRD) region, discuss the difference between our modelled network and the original network, and evaluate its validity through a systemic comparison with a benchmark dataset of actual passenger flows

GIS-based methodology for evaluating the wind-energy potential of territories: A case study from Andalusia (Spain)

In recent years, Spain, in an effort to meet European Union (E.U.) targets, has been developing different strategies to promote the installation of renewable energy plants. In this regard, evaluating territories to assess their potential and thus identify optimum sites for the installation of energy-generating facilities is a crucial task. This paper presents a comprehensive geographic information system (GIS)-based site-selection methodology for wind-power plants in the province of Córdoba, which has hitherto been regarded as unsuitable for this sort of facility owing to the lack of wind resources. Three scenarios have been set out, each of which presents a different set of restrictions. Scenario 2 applies the most stringent restrictions in the specialized literature, and finds no suitable areas for the installation of wind-energy plants. However, Scenario 1, which applies the least stringent restrictions, and Scenario 3, which applies the same restrictions currently in force for other wind turbines already in operation in Andalusia, have led to the identification of several areas that could a priori be considered suitable and now need more detailed analysis. The results illustrate the convenience of undertaking multiscenario analyses

Testing, not modelling, the impact of Cohesion support: a theoretical framework and some preliminary results for the Spanish regions

This paper develops a simple model that can be used to estimate the effectiveness of Cohesion expenditure relative to similar but unsubsidized projects, thereby making it possible to explicitly test an important assumption that is often implicit in estimates of the impact of Cohesion policies. Some preliminary results are reported for the case of infrastructure investment in the Spanish regions.Cohesion policy effectiveness, Structural Fund evaluation

What drives the allocation of motorways? Evidence from Portugal’s fast-expanding network

This study investigates the factors that influenced the allocation of motorways across municipalities in mainland Portugal over the period from 1981 to 2011. Our analysis, based on Poisson Pseudo-maximum Likelihood models, suggests that population size and market potential in 1981 are important determinants of motorway density in 2011. Likewise, physical and geographical variables also help explain the spatial distribution of motorway investment, as terrain ruggedness, distance to the coast, and distance to the border with Spain are negatively associated with motorway density. In addition, we consider the influence of the proximity to historical and pre-existing transport networks on the allocation of motorways; we find that municipalities that are closer to the 1800’s itineraries, the main roads of the 1945’s National Road Plan, and 1981’s train stations appear to have higher motorway densities in 2011, but this effect is concentrated in the vast and sparsely populated area of the country that excludes what we term the highdensity Portuguese “blue banana”. Interestingly, it is also only in this low-density region that partisan alignment between the municipal and the national levels of government appears to affect the allocation of transport investment, which suggests that motorways are more of a political asset in more remote or less urbanised areas.info:eu-repo/semantics/publishedVersio

Direct and Indirect Land Use Impacts of the EU Cohesion Policy. Assessment with the Land Use Modelling Platform

The Cohesion policy for the programming period 2014-2020 is analyzed in terms of its likely land use and environmental impacts using the Land Use Modelling Platform (LUMP). This report describes in detail the process and the methodology by which the ex-ante impact assessment was made, and presents the results for Austria, Czech Republic, Germany, and Poland. The modelling approach can provide insights on the trade-offs between economic growth, investment policies (such as the Cohesion policy), and land use and the environment. In addition, ways to mitigate potentially negative land use and environmental impacts were explored. The future development of the LUMP is discussed in view of planned future work.JRC.H.8-Sustainability Assessmen