Intelligent transportation systems(ITSs)are becoming increasingly popular as they support efficient coordinated transport.ITSs aim to improve the safety,efficiency and reliability of road transportation through integr...Intelligent transportation systems(ITSs)are becoming increasingly popular as they support efficient coordinated transport.ITSs aim to improve the safety,efficiency and reliability of road transportation through integrated approaches to the exchange of relevant information.Mobile adhoc networks(MANETs)and vehicle ad-hoc networks(VANETs)are integral components of ITS.The VANET is composed of interconnected vehicles with sensitivity capabilities to exchange traffic,positioning,weather and emergency information.One of the main challenges in VANET is the reliable and timely dissemination of information between vehicular nodes to improve decision-making processes.This paper illustrates challenges in VANET and reviews possible solutions to improve road safety control and management using V2V and V2I communications.This paper also summarizes existing rules-based and optimized-based solutions,including reducing the effect of mixed environments,obstacles,malfunctions and short wireless ranges on transportation efficiency and reducing false messages that cause unintended vehicle actions and unreliable transportation systems.Additionally,an event simulation algorithm was designed to maximize the benefits of exchangeable messages among vehicles.Furthermore,simulated VANET environments were developed to demonstrate how the algorithm can be used for transformable messages.Experimental results show that coupling of both V2V and V2I messages yielded better results in terms of end-to-end delay and average time.Future research directions were highlighted to be taken into account in the development of ITS and intelligent routing mechanisms.展开更多
Space systems have become a key enabler for a wide variety of applications that are vital to the functioning of advanced societies. The trend is one of quantitative and qualitative increase of this dependence, so much...Space systems have become a key enabler for a wide variety of applications that are vital to the functioning of advanced societies. The trend is one of quantitative and qualitative increase of this dependence, so much so that space systems have been described as a new example of critical infrastructure. This article argues that the existence of critical space infrastructures implies the emergence of a new category of disasters related to disruption risks. We inventory those risks and make policy recommendations for what is, ultimately, a resilience governance issue.展开更多
In recent years,urban resilience has attracted increasing attention from researchers and managers from the international community at the national,regional,and urban levels.Numerous multi-dimensional and cross-discipl...In recent years,urban resilience has attracted increasing attention from researchers and managers from the international community at the national,regional,and urban levels.Numerous multi-dimensional and cross-disciplinary investigations,campaigns,and outlines have significantly promoted the development goal of re-silience in cities worldwide.However,the existing definitions and interpretations of urban resilience still call for a more comprehensive,systematic,and exhaustive analysis as urbanization accelerates and the complex risks of various safety events increase.To this end,we rethink the extension and connotation of urban resilience based on a review and analysis of critical hotspots,realistic demand,and development trends.A conceptual classification with three aspects and three typical tiers of urban resilience is proposed,which further promotes a new definition and interpretation by incorporating the resilience extension of urban systems.In addition,the six-dimensional characteristics are extracted to furnish the urban resilience connotation,and four-stage improvement measures are introduced accordingly.In addition,the newly developed urban resilience is applied to a case analysis of a large-scale disaster,which demonstrates the necessity and significance of this study.The new extension and connotation investigation will be helpful for the improvement and implementation of urban resilience,thereby guiding the construction of resilient cities.展开更多
The past decade has witnessed an acceleration of autonomous vehicle research and development,with technological advances contributed by academia,government,and the industrial and consumer sectors.These advancements ho...The past decade has witnessed an acceleration of autonomous vehicle research and development,with technological advances contributed by academia,government,and the industrial and consumer sectors.These advancements hold the potential to improve society by enhancing transportation safety and throughput,where decreased congestion saves time and reduces vehicle emissions.Two of the key technologies to enable vehicle infrastructure interaction,advanced traffic management,and automated vehicles are automated roadway mapping and reliable vehicle state estimation.In this paper,we present an overview and new methods for the problems automated roadway mapping plus a discussion of the extension of these methods to the problem of vehicle state estimation.Results from the application of these methods to feature mapping and state estimation are presented.展开更多
System health management,which aims to ensure the safe and efficient operation of systems by reducing uncertain risks and cascading failures during their lifetime,is proposed for complex transportation systems and oth...System health management,which aims to ensure the safe and efficient operation of systems by reducing uncertain risks and cascading failures during their lifetime,is proposed for complex transportation systems and other critical infrastructures,especially under the background of the New Infrastructure Projects launched in China.Previous studies proposed numerous approaches to evaluate or improve traffic reliability or efficiency.Nevertheless,most existing studies neglected the core failure mechanism(i.e.,spatio-temporal propagation of traffic congestion).In this article,we review existing studies on traffic reliability management and propose a health management framework covering the entire traffic congestion lifetime,from emergence,evolution to dissipation,based on the study of core failure modes with percolation theory.Aiming to be"reliable,invulnerable,resilient,potential,and active",our proposed traffic health management framework includes modeling,evaluation,diagnosis,and improvement.Our proposed framework may shed light on traffic management for megacities and urban agglomerations around the world.This new approach may offer innovative insights for systems science and engineering in fiiture intelligent infrastructure management.展开更多
Cyber-physical systems(CPSs)in critical infrastructure face serious threats of attack,motivating research into a wide variety of defence mechanisms such as those that monitor for violations of invariants,i.e.logical p...Cyber-physical systems(CPSs)in critical infrastructure face serious threats of attack,motivating research into a wide variety of defence mechanisms such as those that monitor for violations of invariants,i.e.logical properties over sensor and actuator states that should always be true.Many approaches for identifying invariants attempt to do so automatically,typically using data logs,but these can miss valid system properties if relevant behaviours are not well-represented in the data.Furthermore,as the CPS is already built,resolving any design flaws or weak points identified through this process is costly.In this paper,we propose a systematic method for deriving invariants from an analysis of a CPS design,based on principles of the axiomatic design methodology from design science.Our method iteratively decomposes a high-level CPS design to identify sets of dependent design parameters(i.e.sensors and actuators),allowing for invariants and invariant checkers to be derived in parallel to the implementation of the system.We apply our method to the designs of two CPS testbeds,SWaT and WADI,deriving a suite of invariant checkers that are able to detect a variety of single-and multi-stage attacks without any false positives.Finally,we reflect on the strengths and weaknesses of our approach,how it can be complemented by other defence mechanisms,and how it could help engineers to identify and resolve weak points in a design before the controllers of a CPS are implemented.展开更多
In order to facilitate and coordinate spatial data sharing and exchange,many organisations have developed spatial data infrastructures(SDIs).SDI governance plays a pivotal role in the development and evolution of an S...In order to facilitate and coordinate spatial data sharing and exchange,many organisations have developed spatial data infrastructures(SDIs).SDI governance plays a pivotal role in the development and evolution of an SDI,but as SDIs are complex adaptive systems,governing is a challenge.This research therefore proposes a complexity perspective to SDI governance by exploring the use of agent-based modelling to simulate and examine SDI governance interactions.In this agent-based simulation,we examine interactions between SDI stakeholders,data availability and the effects of different governance styles(hierarchical,network and laissez-faire governance)and budget policies.The simulation shows that it is possible to mimic SDI governance dynamics through agent-based modelling.By running different scenarios,it appears that a network approach is more successful compared to a hierarchical or laissez-faire approach.Expert validation shows that overall the results of the simulation are credible and insightful,although improvements can be made to make the model more realistic.With agent-based modelling,SDI governance becomes more tangible and visible,which facilitates discussion and understanding.Agent-based modelling therefore appears to be a helpful new approach in a better understanding of the complexities and dynamics of SDI governance.展开更多
A systematic approach is proposed to the theme of safety,reliability and global quality of complex networks(material and immaterial)by means of special mathematical tools that allow an adequate geometric characterizat...A systematic approach is proposed to the theme of safety,reliability and global quality of complex networks(material and immaterial)by means of special mathematical tools that allow an adequate geometric characterization and study of the operation,even in the presence of multiple obstacles along the path.To that end,applying the theory of graphs to the problem under study and using a special mathematical model based on stochastic geometry,in this article we consider some regular lattices in which it is possible to schematize the elements of the network,with the fundamental cell with six,eight or 2(n+2)obstacles,calculating the probability of Laplace.In this way it is possible to measure the“degree of impedance”exerted by the anomalies along the network by the obstacles examined.The method can be extended to other regular and/or irregular geometric figures,whose union together constitutes the examined network,allowing to optimize the functioning of the complex system considered.展开更多
Water quality,flooding risk,and water consumption in urban areas are emerging issues.Urban impervious surfaces increase stormwater runoff,affecting ecosystems and leading to hydrogeological instability and flooding ri...Water quality,flooding risk,and water consumption in urban areas are emerging issues.Urban impervious surfaces increase stormwater runoff,affecting ecosystems and leading to hydrogeological instability and flooding risk.Sustainable urban design strategies can contribute to counteract the negative impact of anthropic activities both at city-scale and global scale.Green and Blue Infrastructure(GBI)approaches,in particular,are an alternative to stormwater traditional management.In Europe,Sustainable Drainage System implementation copes with impervious surfaces to achieve water quality,amenity,and biodiversity increase.Best Management Practices,developed mainly in the USA,focus on specific measures for sustainable stormwater treatment.Water Sensitive Urban Design,spread in Australia and England,also aims to minimise the impact of developed areas preventing flood risk,limiting water consumption and enhancing environmental quality.In the USA and Canada,Low Impact Development offers design strategies to manage runoff and deliver structural practices to mimic predevelopment processes of infiltration,filtration and detention.展开更多
基金Deanship of Scientific Research at Majmaah University for supporting this work under Project Number No.R-2023-413.
文摘Intelligent transportation systems(ITSs)are becoming increasingly popular as they support efficient coordinated transport.ITSs aim to improve the safety,efficiency and reliability of road transportation through integrated approaches to the exchange of relevant information.Mobile adhoc networks(MANETs)and vehicle ad-hoc networks(VANETs)are integral components of ITS.The VANET is composed of interconnected vehicles with sensitivity capabilities to exchange traffic,positioning,weather and emergency information.One of the main challenges in VANET is the reliable and timely dissemination of information between vehicular nodes to improve decision-making processes.This paper illustrates challenges in VANET and reviews possible solutions to improve road safety control and management using V2V and V2I communications.This paper also summarizes existing rules-based and optimized-based solutions,including reducing the effect of mixed environments,obstacles,malfunctions and short wireless ranges on transportation efficiency and reducing false messages that cause unintended vehicle actions and unreliable transportation systems.Additionally,an event simulation algorithm was designed to maximize the benefits of exchangeable messages among vehicles.Furthermore,simulated VANET environments were developed to demonstrate how the algorithm can be used for transformable messages.Experimental results show that coupling of both V2V and V2I messages yielded better results in terms of end-to-end delay and average time.Future research directions were highlighted to be taken into account in the development of ITS and intelligent routing mechanisms.
基金supported by a grant of the Program for Research,Development and Innovation for Space Technology and Advanced Research(STAR)administered by the Romanian Space Agency,project number 191/2017
文摘Space systems have become a key enabler for a wide variety of applications that are vital to the functioning of advanced societies. The trend is one of quantitative and qualitative increase of this dependence, so much so that space systems have been described as a new example of critical infrastructure. This article argues that the existence of critical space infrastructures implies the emergence of a new category of disasters related to disruption risks. We inventory those risks and make policy recommendations for what is, ultimately, a resilience governance issue.
基金the National Key R&D Program of China(No.2021ZD0111200)the National Science Foundation of China(Grant No.72204134,72174099)the High-tech Discipline Construction Foundation for Universities in Beijing(Safety Science and Engineering).
文摘In recent years,urban resilience has attracted increasing attention from researchers and managers from the international community at the national,regional,and urban levels.Numerous multi-dimensional and cross-disciplinary investigations,campaigns,and outlines have significantly promoted the development goal of re-silience in cities worldwide.However,the existing definitions and interpretations of urban resilience still call for a more comprehensive,systematic,and exhaustive analysis as urbanization accelerates and the complex risks of various safety events increase.To this end,we rethink the extension and connotation of urban resilience based on a review and analysis of critical hotspots,realistic demand,and development trends.A conceptual classification with three aspects and three typical tiers of urban resilience is proposed,which further promotes a new definition and interpretation by incorporating the resilience extension of urban systems.In addition,the six-dimensional characteristics are extracted to furnish the urban resilience connotation,and four-stage improvement measures are introduced accordingly.In addition,the newly developed urban resilience is applied to a case analysis of a large-scale disaster,which demonstrates the necessity and significance of this study.The new extension and connotation investigation will be helpful for the improvement and implementation of urban resilience,thereby guiding the construction of resilient cities.
基金supported in part by the US Department of Transportation Federal Highway Administration[grant number DTFH61-09-C-00018]and[grant number DTFH61-06-D-00006]California Department of Transportation[grant number 65A0261].
文摘The past decade has witnessed an acceleration of autonomous vehicle research and development,with technological advances contributed by academia,government,and the industrial and consumer sectors.These advancements hold the potential to improve society by enhancing transportation safety and throughput,where decreased congestion saves time and reduces vehicle emissions.Two of the key technologies to enable vehicle infrastructure interaction,advanced traffic management,and automated vehicles are automated roadway mapping and reliable vehicle state estimation.In this paper,we present an overview and new methods for the problems automated roadway mapping plus a discussion of the extension of these methods to the problem of vehicle state estimation.Results from the application of these methods to feature mapping and state estimation are presented.
基金This work was supported by the National Natural Science Foundation of China(Grants Nos.71822101,71890973/71890970,71771009,and 61961146005).
文摘System health management,which aims to ensure the safe and efficient operation of systems by reducing uncertain risks and cascading failures during their lifetime,is proposed for complex transportation systems and other critical infrastructures,especially under the background of the New Infrastructure Projects launched in China.Previous studies proposed numerous approaches to evaluate or improve traffic reliability or efficiency.Nevertheless,most existing studies neglected the core failure mechanism(i.e.,spatio-temporal propagation of traffic congestion).In this article,we review existing studies on traffic reliability management and propose a health management framework covering the entire traffic congestion lifetime,from emergence,evolution to dissipation,based on the study of core failure modes with percolation theory.Aiming to be"reliable,invulnerable,resilient,potential,and active",our proposed traffic health management framework includes modeling,evaluation,diagnosis,and improvement.Our proposed framework may shed light on traffic management for megacities and urban agglomerations around the world.This new approach may offer innovative insights for systems science and engineering in fiiture intelligent infrastructure management.
基金the National Research Foundation,Singapore,under its National Satellite of Excellence Programme“Design Science and Technology for Secure Critical Infrastructure”(Award Number:NSoE DeST-SCI2019-0004).
文摘Cyber-physical systems(CPSs)in critical infrastructure face serious threats of attack,motivating research into a wide variety of defence mechanisms such as those that monitor for violations of invariants,i.e.logical properties over sensor and actuator states that should always be true.Many approaches for identifying invariants attempt to do so automatically,typically using data logs,but these can miss valid system properties if relevant behaviours are not well-represented in the data.Furthermore,as the CPS is already built,resolving any design flaws or weak points identified through this process is costly.In this paper,we propose a systematic method for deriving invariants from an analysis of a CPS design,based on principles of the axiomatic design methodology from design science.Our method iteratively decomposes a high-level CPS design to identify sets of dependent design parameters(i.e.sensors and actuators),allowing for invariants and invariant checkers to be derived in parallel to the implementation of the system.We apply our method to the designs of two CPS testbeds,SWaT and WADI,deriving a suite of invariant checkers that are able to detect a variety of single-and multi-stage attacks without any false positives.Finally,we reflect on the strengths and weaknesses of our approach,how it can be complemented by other defence mechanisms,and how it could help engineers to identify and resolve weak points in a design before the controllers of a CPS are implemented.
基金This work is part of the research programme Maps4Society with project number 13717(GOV4SDI)which is(partly)financed by the Dutch Research Council(NWO).
文摘In order to facilitate and coordinate spatial data sharing and exchange,many organisations have developed spatial data infrastructures(SDIs).SDI governance plays a pivotal role in the development and evolution of an SDI,but as SDIs are complex adaptive systems,governing is a challenge.This research therefore proposes a complexity perspective to SDI governance by exploring the use of agent-based modelling to simulate and examine SDI governance interactions.In this agent-based simulation,we examine interactions between SDI stakeholders,data availability and the effects of different governance styles(hierarchical,network and laissez-faire governance)and budget policies.The simulation shows that it is possible to mimic SDI governance dynamics through agent-based modelling.By running different scenarios,it appears that a network approach is more successful compared to a hierarchical or laissez-faire approach.Expert validation shows that overall the results of the simulation are credible and insightful,although improvements can be made to make the model more realistic.With agent-based modelling,SDI governance becomes more tangible and visible,which facilitates discussion and understanding.Agent-based modelling therefore appears to be a helpful new approach in a better understanding of the complexities and dynamics of SDI governance.
文摘A systematic approach is proposed to the theme of safety,reliability and global quality of complex networks(material and immaterial)by means of special mathematical tools that allow an adequate geometric characterization and study of the operation,even in the presence of multiple obstacles along the path.To that end,applying the theory of graphs to the problem under study and using a special mathematical model based on stochastic geometry,in this article we consider some regular lattices in which it is possible to schematize the elements of the network,with the fundamental cell with six,eight or 2(n+2)obstacles,calculating the probability of Laplace.In this way it is possible to measure the“degree of impedance”exerted by the anomalies along the network by the obstacles examined.The method can be extended to other regular and/or irregular geometric figures,whose union together constitutes the examined network,allowing to optimize the functioning of the complex system considered.
文摘Water quality,flooding risk,and water consumption in urban areas are emerging issues.Urban impervious surfaces increase stormwater runoff,affecting ecosystems and leading to hydrogeological instability and flooding risk.Sustainable urban design strategies can contribute to counteract the negative impact of anthropic activities both at city-scale and global scale.Green and Blue Infrastructure(GBI)approaches,in particular,are an alternative to stormwater traditional management.In Europe,Sustainable Drainage System implementation copes with impervious surfaces to achieve water quality,amenity,and biodiversity increase.Best Management Practices,developed mainly in the USA,focus on specific measures for sustainable stormwater treatment.Water Sensitive Urban Design,spread in Australia and England,also aims to minimise the impact of developed areas preventing flood risk,limiting water consumption and enhancing environmental quality.In the USA and Canada,Low Impact Development offers design strategies to manage runoff and deliver structural practices to mimic predevelopment processes of infiltration,filtration and detention.
