Multi-objective model for optimizing railway infrastructure asset renewal

Trabalho inspirado num problema real da empresa Infraestruturas de Portugal, EP.A multi-objective model for managing railway infrastructure asset renewal is presented. The model aims to optimize three objectives, while respecting operational constraints: levelling investment throughout multiple years, minimizing total cost and minimizing work start postponements. Its output is an optimized intervention schedule. The model is based on a case study from a Portuguese infrastructure management company, which specified the objectives and constraints, and reflects management practice on railway infrastructure. The results show that investment levelling greatly influences the other objectives and that total cost fluctuations may range from insignificant to important, depending on the condition of the infrastructure. The results structure is argued to be general and suggests a practical methodology for analysing trade-offs and selecting a solution for implementation.info:eu-repo/semantics/publishedVersio

Economic Impacts of GO TO 2040

The economy of the Chicago metropolitan region has reached a critical juncture. On the one hand, Chicagoland is currently a highly successful global region with extraordinary assets and outputs. The region successfully made the transition in the 1980s and 1990s from a primarily industrial to a knowledge and service-based economy. It has high levels of human capital, with strong concentrations in information-sector industries and knowledge-based functional clusters -- a headquarters region with thriving finance, business services, law, IT and emerging bioscience, advanced manufacturing and similar high-growth sectors. It combines multiple deep areas of specialization, providing the resilience that comes from economic diversity. It is home to the abundant quality-of-life amenities that flow from business and household prosperity.On the other hand, beneath this static portrait of our strengths lie disturbing signs of a potential loss of momentum. Trends in the last decade reveal slowing rates, compared to other regions, of growth in productivity and gross metropolitan product. Trends in innovation, new firm creation and employment are comparably lagging. The region also faces emerging challenges with respect to both spatial efficiency and governance.In this context, the Chicago Metropolitan Agency for Planning (CMAP) has just released GO TO 2040, its comprehensive, long-term plan for the Chicago metropolitan area. The plan contains recommendations aimed at shaping a wide range of regional characteristics over the next 30 years, during which time more than 2 million new residents are anticipated. Among the chief goals of GO TO 2040 are increasing the region's long-term economic prosperity, sustaining a high quality of life for the region's current and future residents and making the most effective use of public investments. To this end, the plan addresses a broad scope of interrelated issues which, in aggregate, will shape the long-term physical, economic, institutional and social character of the region.This report by RW Ventures, LLC is an independent assessment of the plan from a purely economic perspective, addressing the impacts that GO TO 2040's recommendations can be expected to have on the future of the regional economy. The assessment begins by describing how implementation of GO TO 2040's recommendations would affect the economic landscape of the region; reviews economic research and practice about the factors that influence regional economic growth; and, given both of these, articulates and illustrates the likely economic impacts that will flow from implementation of the plan. In the course of reviewing the economic implications of the plan, the assessment also provides recommendations of further steps, as the plan is implemented, for increasing its positive impact on economic growth

The Dynamics of Vehicular Networks in Urban Environments

Vehicular Ad hoc NETworks (VANETs) have emerged as a platform to support intelligent inter-vehicle communication and improve traffic safety and performance. The road-constrained, high mobility of vehicles, their unbounded power source, and the emergence of roadside wireless infrastructures make VANETs a challenging research topic. A key to the development of protocols for inter-vehicle communication and services lies in the knowledge of the topological characteristics of the VANET communication graph. This paper explores the dynamics of VANETs in urban environments and investigates the impact of these findings in the design of VANET routing protocols. Using both real and realistic mobility traces, we study the networking shape of VANETs under different transmission and market penetration ranges. Given that a number of RSUs have to be deployed for disseminating information to vehicles in an urban area, we also study their impact on vehicular connectivity. Through extensive simulations we investigate the performance of VANET routing protocols by exploiting the knowledge of VANET graphs analysis.Comment: Revised our testbed with even more realistic mobility traces. Used the location of real Wi-Fi hotspots to simulate RSUs in our study. Used a larger, real mobility trace set, from taxis in Shanghai. Examine the implications of our findings in the design of VANET routing protocols by implementing in ns-3 two routing protocols (GPCR & VADD). Updated the bibliography section with new research work

Strategies and Measures for Sustainable Urban Transport Systems

Increasing sustainability of urban transport systems is a crucial objective of all strategic plans both at national and European level. Different strategies and measures can be adopted to improve the efficiency of transport systems, according to a large set of factors that can affect the results of the implemented actions. A comprehensive study has been carried out in order to define a methodology able to define effective and efficient strategies and measures, allowing to increase the sustainability level of different kinds of cities, from small-medium sized to large metropolitan areas. The methodology has been tested on a group of 50 Italian cities, whose characteristics have been analysed through an initial set of more than 200 indicators. Three main groups of indicators have been taken into account: State indicators, Sustainability indicators, Policy indicators. The main aim has been to identify existing relationships between Sustainability and Policy indicators for cities showing commonalities in terms of State indicators. A correlation analysis allowed to identify 53 relevant indicators from the initial set of 200, while a cluster analysis, based on a hierarchical model, allowed to group the cities into five different groups, according to their population size and density. Correlations between relevant indicators have also been analysed within each group, while linear regression models have allowed to describe some functional relations between Policy and Sustainability indicators. A benchmarking exercise has allowed to identify strategies and measures adopted by the best performers within each group, hence defining possible paths to a better sustainability level for the remaining cities. Finally, recommendations for a correct urban mobility planning procedures have been produce

Decomposing generalized transport costs using index numbers: A geographical analysis of economic and infrastructure fundamentals

We use the economic theory approach to index numbers in order to improve the existing definitions and decompositions of generalized transport costs (GTCs), and thus to obtain a better understanding of their economic and infrastructure determinants. Using this approach we accurately measure the contribution made to reducing GTCs by the variation in operating costs and accessibility variables, and discuss to what extent transportation policy has been successful in reducing GTCs in terms of market competition and infrastructure investments. To implement the optimizing behaviour of transportation firms when choosing minimum cost itineraries, we compile a new economic database on road freight transportation at a highly detailed provincial level, which is then embedded into a GIS to show the digitalized road networks corresponding to five-year intervals between 1980 and 2007. Average GTCs weighted by trade flows have decreased by -16.3% in Spain, with infrastructure policy leading the way in providing notable accessibility improvements in terms of lower times and distances. The contribution of infrastructure is double that of economic cost, whose trends are mainly driven by technological and market determinants rather than by specific competition and regulatory policies promoted by the administrations. We find large territorial disparities in GTC levels and variations, but also significant clusters where the market and network effects on GTC reduction show relevant and diverse degrees of spatial association. We finally conclude that after three decades of active transportation policy aimed mainly at intensifying investment in road infrastructure, there has been a significant increase in territorial cohesion in terms of GTCs and their components.Generalized transport costs; Index number theory; Infrastructure; GIS; Territorial cohesion.