The Experts below are selected from a list of 31383 Experts worldwide ranked by ideXlab platform
Erik Jenelius - One of the best experts on this subject based on the ideXlab platform.
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road Network Vulnerability analysis conceptualization implementation and application
Computers Environment and Urban Systems, 2015Co-Authors: Erik Jenelius, Lars-göran MattssonAbstract:The paper describes a process for road Network Vulnerability analysis, from (i) the conceptual definition of Vulnerability measures, through (ii) the derivation of practical indicators and models adapted to available data and their implementation in computational procedures, to (iii) the application of the methodology in case studies. In the first step, the Vulnerability concept is defined and quantified formally, and distinct user and technological perspectives are highlighted. In the second step, the conceptual measures are adapted and calculated according to the conditions, requirements and goals of a particular analysis. The paper describes practical indicators and algorithms developed for large-scale Vulnerability analyses. For the third step, the paper analyzes both single link closures and area-covering disruptions and the distribution of impacts among different regions in a case study on the Swedish road transport system. The spatial patterns are put in connection with the regional variations in location and travel patterns and Network density. Finally, the implications for policy and possible approaches to Vulnerability management are discussed.
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road Network Vulnerability analysis of area covering disruptions a grid based approach with case study
Transportation Research Part A-policy and Practice, 2012Co-Authors: Erik Jenelius, Lars-göran MattssonAbstract:Road Network Vulnerability analysis of area-covering disruptions: A grid-based approach with case study
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The impact of Network density, travel and location patterns on regional road Network Vulnerability
2012Co-Authors: Erik Jenelius, Lars-göran MattssonAbstract:The impact of Network density, travel and location patterns on regional road Network Vulnerability
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Network structure and travel patterns explaining the geographical disparities of road Network Vulnerability
Journal of Transport Geography, 2009Co-Authors: Erik JeneliusAbstract:Inevitably, links in the road Network are sometimes disrupted because of adverse weather, technical failures or major accidents. Link closures may have different economic and societal consequences depending on in which regions they occur (regional importance), and users may be affected differently depending on where they travel (regional exposure). In this paper we investigate in what way these geographical disparities depend on the road Network structure and travel patterns. We propose aggregate supply-side (link redundancy, Network scale, road density, population density) and demand-side (user travel time, traffic load) indicators and combine them in statistical regression models. Using the Swedish road Network as a case study, we find that regional importance is largely determined by the Network structure and the average traffic load in the region, whereas regional exposure is largely determined by the Network structure and the average user travel time. Our findings show that the long-term Vulnerability disparities stem from fundamental properties of the transport system and the population densities. Quantitatively, they show how Vulnerability depends on different variables, which is of interest for robust Network design.
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importance and exposure in road Network Vulnerability analysis
Transportation Research Part A-policy and Practice, 2006Co-Authors: Erik Jenelius, Tom Petersen, Lars-göran MattssonAbstract:The reliability and Vulnerability of critical infrastructures have attracted a lot of attention recently. In order to assess these issues quantitatively, operational measures are needed. Such measures can also be used as guidance to road administrations in their prioritisation of maintenance and repair of roads, as well as for avoiding causing unnecessary disturbances in the planning of roadwork. The concepts of link importance and site exposure are introduced. In this paper, several link importance indices and site exposure indices are derived, based on the increase in generalised travel cost when links are closed. These measures are divided into two groups: one reflecting an "equal opportunities perspective", and the other a "social efficiency perspective". The measures are calculated for the road Network of northern Sweden. Results are collected in a GIS for visualisation, and are presented per link and municipality. In view of the recent great interest in complex Networks, some topological measures of the road Network are also presented.
Lars-göran Mattsson - One of the best experts on this subject based on the ideXlab platform.
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road Network Vulnerability analysis conceptualization implementation and application
Computers Environment and Urban Systems, 2015Co-Authors: Erik Jenelius, Lars-göran MattssonAbstract:The paper describes a process for road Network Vulnerability analysis, from (i) the conceptual definition of Vulnerability measures, through (ii) the derivation of practical indicators and models adapted to available data and their implementation in computational procedures, to (iii) the application of the methodology in case studies. In the first step, the Vulnerability concept is defined and quantified formally, and distinct user and technological perspectives are highlighted. In the second step, the conceptual measures are adapted and calculated according to the conditions, requirements and goals of a particular analysis. The paper describes practical indicators and algorithms developed for large-scale Vulnerability analyses. For the third step, the paper analyzes both single link closures and area-covering disruptions and the distribution of impacts among different regions in a case study on the Swedish road transport system. The spatial patterns are put in connection with the regional variations in location and travel patterns and Network density. Finally, the implications for policy and possible approaches to Vulnerability management are discussed.
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road Network Vulnerability analysis of area covering disruptions a grid based approach with case study
Transportation Research Part A-policy and Practice, 2012Co-Authors: Erik Jenelius, Lars-göran MattssonAbstract:Road Network Vulnerability analysis of area-covering disruptions: A grid-based approach with case study
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The impact of Network density, travel and location patterns on regional road Network Vulnerability
2012Co-Authors: Erik Jenelius, Lars-göran MattssonAbstract:The impact of Network density, travel and location patterns on regional road Network Vulnerability
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importance and exposure in road Network Vulnerability analysis
Transportation Research Part A-policy and Practice, 2006Co-Authors: Erik Jenelius, Tom Petersen, Lars-göran MattssonAbstract:The reliability and Vulnerability of critical infrastructures have attracted a lot of attention recently. In order to assess these issues quantitatively, operational measures are needed. Such measures can also be used as guidance to road administrations in their prioritisation of maintenance and repair of roads, as well as for avoiding causing unnecessary disturbances in the planning of roadwork. The concepts of link importance and site exposure are introduced. In this paper, several link importance indices and site exposure indices are derived, based on the increase in generalised travel cost when links are closed. These measures are divided into two groups: one reflecting an "equal opportunities perspective", and the other a "social efficiency perspective". The measures are calculated for the road Network of northern Sweden. Results are collected in a GIS for visualisation, and are presented per link and municipality. In view of the recent great interest in complex Networks, some topological measures of the road Network are also presented.
Johan W. Joubert - One of the best experts on this subject based on the ideXlab platform.
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The Road most Travelled: The Impact of Urban Road Infrastructure on Supply Chain Network Vulnerability
Networks and Spatial Economics, 2018Co-Authors: Nadia M. Viljoen, Johan W. JoubertAbstract:Making a supply chain more resilient and making it more efficient are often diametrically opposed objectives. Managers have to make informed trade-offs when designing their supply chain Networks. There are many methods available to quantify and optimise efficiency. Unfortunately the same cannot be said for Vulnerability and resilience. We propose a method to quantify the impact that a supply chain’s dependence on the underlying transport infrastructure has on its Vulnerability. The dependence relationship is modelled using multilayered complex Network theory. We develop two metrics relating to the unique collection of shortest path sets namely redundancy and overlap. To test the relationships between these metrics and supply chain Vulnerability we simulate progressive random link disruption of the urban road Network and assess the impact this has on Fully Connected, Single Hub and Double Hub Network archetypes. The results show that redundancy and overlap of the collection of shortest paths are significantly related to supply chain resilience, however under a purely random disturbance regime they hold no predictive power. This paper builds a foundation for a new field of inquiry into supply chain Vulnerability by presenting a flexible mathematical formulation of the multilayered Network and defining and testing two novel metrics that could be incorporated into supply chain Network design decisions.
Ettore Bompard - One of the best experts on this subject based on the ideXlab platform.
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complex Network based cascading faults graph for the analysis of transmission Network Vulnerability
IEEE Transactions on Industrial Informatics, 2019Co-Authors: Xiaoguang Wei, Ettore Bompard, Tao Huang, Shibin Gao, Tao WangAbstract:Transmission Network Vulnerability (TNV) assessment is a key issue in power systems to identify the vulnerable components against accidents or malicious threats. Recently, constructing the topological Vulnerability indices, particularly extended topological indices, is a popular method to evaluate the Network Vulnerability. However, the topological Vulnerability indices cannot reveal the mechanism of fault propagation. To overcome the shortcomings, this paper proposes a new method to assess the TNV through the cascading faults graph (CFG) based on fault chains, which is a statistical graph that comprehensively considers the physical, operational, and structural features of electrical Networks. Based on the complex Network theory (CNT), the scale-free properties of the CFG are revealed through simulations on various transmission Networks by corresponding the degree distribution of the CFG; then, the model constancy of the CFG is analyzed. Resorting to the CFG, a set of indices from the CNT is used to identify the vulnerable branches of transmission Networks. Illustrative applications are applied to the IEEE 39-bus and 118-bus test systems to demonstrate the effectiveness of the proposed method.
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A Novel Cascading Faults Graph Based Transmission Network Vulnerability Assessment Method
IEEE Transactions on Power Systems, 2018Co-Authors: Junbo Zhao, Tao Huang, Ettore BompardAbstract:This paper proposes a novel cascading faults graph (CFG) based on fault chain theory to assess the transmission Network Vulnerability. The proposed CFG is able to effectively reveal the mechanism of fault propagation in a transmission Network by transforming an electrical Network with spatial information into a fault propagation graph with temporal information, thus providing a better way for transmission Network Vulnerability assessment. Numerical results on IEEE 39-, 118-bus systems and French grid demonstrate the effectiveness of the proposed method.
Nadia M. Viljoen - One of the best experts on this subject based on the ideXlab platform.
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The Road most Travelled: The Impact of Urban Road Infrastructure on Supply Chain Network Vulnerability
Networks and Spatial Economics, 2018Co-Authors: Nadia M. Viljoen, Johan W. JoubertAbstract:Making a supply chain more resilient and making it more efficient are often diametrically opposed objectives. Managers have to make informed trade-offs when designing their supply chain Networks. There are many methods available to quantify and optimise efficiency. Unfortunately the same cannot be said for Vulnerability and resilience. We propose a method to quantify the impact that a supply chain’s dependence on the underlying transport infrastructure has on its Vulnerability. The dependence relationship is modelled using multilayered complex Network theory. We develop two metrics relating to the unique collection of shortest path sets namely redundancy and overlap. To test the relationships between these metrics and supply chain Vulnerability we simulate progressive random link disruption of the urban road Network and assess the impact this has on Fully Connected, Single Hub and Double Hub Network archetypes. The results show that redundancy and overlap of the collection of shortest paths are significantly related to supply chain resilience, however under a purely random disturbance regime they hold no predictive power. This paper builds a foundation for a new field of inquiry into supply chain Vulnerability by presenting a flexible mathematical formulation of the multilayered Network and defining and testing two novel metrics that could be incorporated into supply chain Network design decisions.