An analysis of the Spanish high capacity road network criticality

The analysis of complex networks has been carried out in different fields using an ample variety of method and concepts. Recently, in the general literature of regional economics, the concepts of resilience, connectivity, vulnerability and criticality have been gaining their momentum. The aim of this paper is to provide an analytical framework, using well-known accessibility indicators, in order to calculate the critical links or road sections of the Spanish high-capacity road network. Our analysis will be based on approximately four hundred sections that will be classified in five different groups according to their criticality degree in the whole network. Our analysis will be complemented with the comparison of the results obtained in five different scenarios, namely the average criticality using the effects on the whole country, Madrid, Barcelona, Valencia and Pontevedra. Furthermore, the paper will also analyze what kind of intrinsic characteristics of the sections favor or not the links’ criticality using a method based on a classification and regression tree. This analysis is crucial to understand other important concepts that are recently being studied in network and spatial economics, like, for example, resilience and vulnerability. It is concluded that the number of relations or routes, being a trunk or not, the road density and the time to Madrid capital play an important role in the criticality of the roads section in the high capacity road network.     

About attitudes and perceptions: finding the proper way to consider latent variables in discrete choice models

We provide an in-depth theoretical discussion about the differences between individual-specific latent constructs (representing attitudes, for example, but also other characteristics such as values or personality traits) and alternative-specific latent constructs (that may represent perceptions) affecting the choice-making process of individuals; we also carry out an empirical exercise to analyze their effects. This discussion is of importance, as the majority of papers considering attitudinal latent variables just take these as attributes affecting directly the utility of a certain alternative, while systematic taste variations are rarely considered and perceptions are mostly ignored. The results of our case study show that perceptions may indeed affect the decision making process and that they are able to capture a significant part of the variability that is normally explained by alternative specific constants. Furthermore, our results indicate that attitudes may be a reason for systematic taste variations, and that a proper categorization of latent variables, in accordance with underlying theory, may outperform the customary assumption of linearity.     

Telemetric system for monitoring and automation of railroad networks

This paper describes a new method of real-time train monitoring based on the ZigBee/IEEE 802.15.4 protocol. The system consists of a mobile device embedded in the moving train which transmits parameter signals that are being measured by a base unit with the help of routers. When applied, the technique monitors and controls vehicles operating on permanent routes, making a real-time evaluation of their performance and location, and allowing an effective planning of trains. It consists of a low cost, low power consumption and safe modular technology capable of monitoring many different variables simultaneously.     

Marketing management at the world's major ports

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.     

Fishermen’s training and use of safety equipment: A case-study of the Artisanal Fleet of Andalusia

This article is intended as a contribution to safety and health in small-scale/artisanal fishing in the autonomous region of Andalusia, Spain. Training is examined as a key element for reducing risks and therefore the serious number of accidents that occur in the fishery work sector as one of those that is statistically reflected as such and discusses the international and Spanish regulations. The case study focuses on the use of safety equipment in this fishing fleet and highlights the improper use of safety equipment and lack of a health and safety culture. Training is examined as a key element in promoting health and safety awareness in this group.     

Characterizing European high speed train stations using intermodal time and entropy metrics

This paper presents a quantitative method for characterizing high speed train stations in terms of passenger intermodality. The aim of the procedure is two-fold: firstly, the method is to be used as an objective measure for comparing stations in order to detect suboptimal points and improve the performance of stations as nodal points; secondly, the method provides a means to embed intermodality into regional accessibility models, allowing comprehensive modelling at lower scales. The empirical base of the work comprises data from 27 European high speed rail stations, which is deemed an appropriate statistical sample for the whole European rail network. Using the entropy metric, we found that several different patterns emerged: there was a clear hierarchy of stations which was linked to their respective roles within the system, while strong constraints impeded stations from performing optimally as true intermodal nodes.     

PACDIN statement of methods

PAntograph–Catenary Dynamic Interaction (PACDIN) is a code developed by the vehicle technology research centre (CITV) of the Universitat Politècnica de València in collaboration with the railway company Talgo S.L. The model of the catenary is a finite element model using absolute nodal coordinates. It is based on a general formulation that can be applied for analysing a wide range of catenary configurations, including stitch wire, transitions or non-straight path tracks. The formulation is fully non-linear and includes large deformations, dropper slackening and contact interaction. The model is linearised when deformations are small, as in the case of the benchmark dynamic analysis. The results of the PACDIN code show a good agreement with the average results of other benchmark codes.     

Spatial distribution patterns of demersal and epibenthic communities on the Galician continental shelf (NW Spain)

Spatial distribution patterns of epibenthic communities on the Galician continental shelf were studied using multivariate methods. Data came from 5 surveys carried out in 2002, 2003 and 2004. Beam trawls and otter trawls were used to study epibenthic communities along 8 transects perpendicular to the coastline. The role of depth, season, latitude and sediment characteristics was examined. Seven habitats were described according to bathymetry and sediment characteristics. There were weak linear relationships between environmental variables and species richness, biomass and species diversity. However, the canonical analysis showed that depth and sediment characteristics greatly influence smaller epibenthic communities sampled by beam trawl. Six assemblages were obtained for beam trawls: inner shelf mud, very fine sands, and fine sands, middle shelf sands, and outer shelf very fine sands, and fine sands. Five assemblages were identified for larger-sized and swimming epibenthos sampled with otter trawls. These assemblages were also determined according to depth and sediment type but sediment characteristics were less important. Otter trawl assemblages were the same as the beam trawl ones, except for on the outer shelf where no differences between sediment type were detected. For both gears, inner and outer shelf assemblages displayed a higher biotic variability than the middle shelf, as a consequence of a higher environmental heterogeneity. Typifying species were mainly eurytopic in the middle shelf, whereas eurytopic and stenotopic species characterised the inner and outer shelves.     

On-road emissions from urban buses with SCR + Urea and EGR + DPF systems using diesel and biodiesel

Due to growing concerns about NO_x and particulate matter (PM) emissions from diesel engines, stricter regulations are being introduced requiring advanced emission control technology. In response the diesel industry has begun testing various emission control technologies and applying them. To assess vehicle renewal policies of bus companies, two exhaust after-treatment technologies are compared: the combination of a diesel particulate filter and an exhaust gas re-circulation system and the combination of a selective catalytic reduction and urea. On-board emission measurements were conducted under real-world driving conditions on a specific bus route in the city of Madrid.     

A literature review of mobility services: definitions,modelling state-of-the-art,and key considerations for a conceptual modelling framework

ABSTRACT

This paper presents a comprehensive literature review focused on the supply side of mobility services, providing relevant insights at the conceptual, operational, and modelling levels. Definitions are first drawn from the Mobility as a Service paradigm due to its predominance in the literature. This is followed by an assessment of the operational features of a range of mobility services, including carsharing, bikesharing, ridehailing, and demand responsive transit. To conclude the review, the state-of-the-art in modelling approaches for mobility services is reported, at different levels of complexity and integration. Three of the most important findings and arguments from this paper suggest that a high degree of generality exists for operational features of mobility services; that it is essential to make a distinction between Mobility as a Service and a mobility service in isolation; along with the argument that human agency should be carefully considered in modelling efforts, both for user agent and driver agent decision-making processes. Finally, key considerations are proposed for the future development of a conceptual framework for modelling the supply side of mobility services, which would have a generic service provider model as its core component.