1,721,088 research outputs found
Vulnerability assessment framework for interdependent critical infrastructures: case-study for Great Britain’s rail network
Full text linkCritical infrastructures vulnerability assessment involves understanding various sociotechnological aspects of modern day infrastructures. While vulnerabilities exist at different scales, failures of large-scale installations in infrastructures are significant because they lead towards widespread social and economic disruptions. There is growing awareness of the multiple potential causes of failure, including those due to dependence upon other infrastructures. This paper establishes a framework for national analysis of vulnerability of interdependent infrastructures. We present: (i) A mathematical formulation of the vulnerability assessment; (ii) Network models for infrastructures that take in account the geographic, physical and operational characteristics of connecting nodes and edges; (iii) Interdependency mapping models that establish relationships between different subsystems within and across infrastructures; and (iv) Methods for implementing failure and disruption calculations. The methodology is demonstrated for Great Britain’s railway infrastructure, for which we have built detailed interdependency mappings between critical assets and infrastructures that support railway operations. Two key vulnerability assessment results, produced to examine failure impacts of such assets on railway passenger trip flows, include: (i) Random failure outcomes; and (ii) Flood vulnerability outcomes. The results show which critical infrastructure interdependencies potentially have large impacts on railway operations, providing a useful analysis tool for further risk and adaptation planning
The African Transport Systems Database: an open geospatial database of multi-modal connected networks
No full textWe present the first comprehensive geolocated multi-modal transport database for the whole continent of Africa, the African Transport Systems Database (AfTS-Db), including road, rail, aviation, maritime and inland waterway networks. To do so, we created and standardized asset and network data across all transport modes, including inter-modal connections, attributes of road and rail corridors and estimated annual statistics for airports and ports. The African Transport Systems Database includes 234 airports including their airline routes, 179 maritime ports and their connections with each other, 132 inland ports and docking sites with river and lake connections, 6,057 railway stations connected across 99,373 kilometers of rail lines, and 1,004,512 kilometers of roads mainly comprised of all motorways, trunk roads, primary and secondary routes across Africa and some local roads that connect to other transport modes. The AfTS-Db provides key information for transport planning, resilience assessments, asset management and development of transport models and applications. Furthermore, we expect the data will also be of relevance for environmental, health, social and economic studies
Risk and resilience assessment of complex infrastructure networks – a system-of-systems approach to rail networks
Full text linkThe railway is an important critical national infrastructure network in many western countries and by its nature is exposed to diverse threats ranging from extreme weather and climate change risks, man-made and malevolent activities. The complex nature of the interdependencies across the respective systems that make up a typical rail network can result in the propagation of network failures with serious consequences for the movement of trains, passengers, goods and services. Recent disruption events have shown how rapid and widescale the impact of failures can be on complex interdependent rail networks, and with the projection of increased risk from extreme weather and climate change events, there is a need for robust methodologies that can address this growing complexity with applicability to real-world networks.
The aim of this thesis is therefore to develop models and methodologies for analysing the risk and resilience of large scale interdependent rail infrastructure networks. It introduces multi-scale, system-of-systems based methodologies and applied analysis that provides important new insights into interdependent infrastructure network risk and resilience at national scale using real-world case studies. The thesis comprises three parts. First, a theoretical network-based model of the multi-track layout is built to replicate the actual operational functionality of the rail network which is tested using a real-world national timetable dataset for Great Britain. This model is calibrated using an empirical dataset of journey disruptions to arrive at a robust journey disruption network model. Next, by adopting a complex network-based modelling approach, real-world asset data is integrated from the respective systems of the national rail network in Great Britain to represent the physical interconnectivity that exists within and between its interdependent infrastructure systems. The coupling of both models give rise to an integrated infrastructure network model which is used to simulate scenarios of risk to the traction power network and resilience modelling. Lastly, the impact of extreme weather risks is studied with the development of a flood risk methodology which is tested by carrying out a comprehensive risk assessment of the national rail network in Great Britain. The criticality of individual assets is calculated by summing the direct impacts, with the indirect impacts measured in terms of train and passenger disruptions.
The development of robust methodologies and research models that represent the actual physical, geographic and functional interdependencies across rail networks using real-world asset datasets allows for the testing of multiple scenarios of risk and resilience which can be used to support robust decision making in complex networks. This research therefore presents new theoretical insights and practical methodologies with direct applicability to academia, infrastructure managers, policy and decision makers across Great Britain and beyond
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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