scholarly journals Identifying Sensitive Components in Infrastructure Networks via Critical Flows

2019 ◽  
Author(s):  
James Williams
Keyword(s):  
Reliability Analysis ◽  
Critical Infrastructure ◽  
Urban Systems ◽  
Centrality Measures ◽  
Critical Flow ◽  
Infrastructure Networks ◽  
Component Importance ◽  
Infrastructure System ◽  
Critical Components ◽  
The Impact

This paper introduces a novel set of component importance measures that are based on the concept of critical flow. Various research communities have developed techniques for identifying critical components of networks. The methods in this paper extend previous work on flow-based centrality measures by adapting them to the assessment of critical infrastructure in urban systems. The motivation is to provide municipalities with a means of reasoning about the impact of urban interventions. An infrastructure system is represented as a flow network in which demand nodes are assigned both demand values and criticality ratings. Sensitive elements in the network are those that carry critical flows, where a flow is deemed critical to the extent that it satisfies critical demand. A method for computing these flows is presented, and its utility is demonstrated by comparing the new measures to existing flow centrality measures. The paper also shows how the method may be combined with standard approaches to reliability analysis.

scholarly journals An Overview of Various Importance Measures of Reliability System

2017 ◽  
Vol 2 (3) ◽  
pp. 150-171 ◽  
Author(s):  
Kalpesh P. Amrutkar ◽  
Kirtee K. Kamalja
Keyword(s):  
Reliability Analysis ◽  
System Reliability ◽  
System Failure ◽  
Numerical Rank ◽  
Reliability Improvement ◽  
System Reliability Analysis ◽  
Component Importance ◽  
Critical Components ◽  
The Impact ◽  
Reliability Systems

One of the purposes of system reliability analysis is to identify the weaknesses or the critical components in a system and to quantify the impact of component’s failures. Various importance measures are being introduced by many researchers since 1969. These component importance measures provide a numerical rank to determine which components are more important to system reliability improvement or more critical to system failure. In this paper, we overview various components importance measures and briefly discuss them with examples. We also discuss some other extended importance measures and review the developments in study of various importance measures with respect to some of the popular reliability systems.

scholarly journals Critical Flow Centrality Measures on Interdependent Networks with Time-Varying Demands

2019 ◽  
Author(s):  
James Williams
Keyword(s):  
Flow Analysis ◽  
Network Capacity ◽  
Scale Model ◽  
Centrality Measures ◽  
Critical Flow ◽  
Degradation Analysis ◽  
Standard Component ◽  
Novel Method ◽  
Critical Components ◽  
Support Decision Making

This paper describes a novel method for allowing urban planners and municipal engineers to identify critical components of interdependent infrastructure networks whose attributes vary over time. The method is based on critical flow analysis, wherein system components are ranked by their role in facilitating the flow of resources to critical locations. The intent of the method is to support decision making by providing a means by which stakeholders can reason about the way in which changes in supply, demand, or network capacity can alter the distribution of critical flows within an urban environment. Individual infrastructure systems are modeled as networks that can be linked to one another by physical and geospatial dependencies. A simple instantiation of the method is presented and evaluated on a district-scale model of a city that contains water and electricity networks. The paper also discusses two forms of reliability analysis based on critical flows: a composite measure incorporating edge reliability, and a variation on standard component failure/degradation analysis.

scholarly journals Hotspots of boundary accumulation: dynamics and statistics of micro-swimmers in flowing films

2016 ◽  
Vol 13 (115) ◽  
pp. 20150936 ◽  
Author(s):  
Arnold J. T. M. Mathijssen ◽  
Amin Doostmohammadi ◽  
Julia M. Yeomans ◽  
Tyler N. Shendruk
Keyword(s):  
Solid Wall ◽  
Critical Value ◽  
Hydrodynamic Interactions ◽  
Critical Flow ◽  
Natural Environments ◽  
Flow Strength ◽  
Surfaces And Interfaces ◽  
Biological Flows ◽  
The Impact ◽  
Systematic Framework

Biological flows over surfaces and interfaces can result in accumulation hotspots or depleted voids of microorganisms in natural environments. Apprehending the mechanisms that lead to such distributions is essential for understanding biofilm initiation. Using a systematic framework, we resolve the dynamics and statistics of swimming microbes within flowing films, considering the impact of confinement through steric and hydrodynamic interactions, flow and motility, along with Brownian and run–tumble fluctuations. Micro-swimmers can be peeled off the solid wall above a critical flow strength. However, the interplay of flow and fluctuations causes organisms to migrate back towards the wall above a secondary critical value. Hence, faster flows may not always be the most efficacious strategy to discourage biofilm initiation. Moreover, we find run–tumble dynamics commonly used by flagellated microbes to be an intrinsically more successful strategy to escape from boundaries than equivalent levels of enhanced Brownian noise in ciliated organisms.

scholarly journals Whose Health in Whose City? A Systems Thinking Approach to Support and Evaluate Plans, Policies, and Strategies for Lasting Urban Health

2021 ◽  
Vol 13 (21) ◽  
pp. 12225
Author(s):  
Silvio Cristiano ◽  
Samuele Zilio
Keyword(s):  
Public Health ◽  
Urban Planning ◽  
Systems Thinking ◽  
Urban Health ◽  
Urban Governance ◽  
Well Being ◽  
World Health ◽  
Urban Systems ◽  
Health Issues ◽  
The Impact

An increasing interest has been present in scientific literature and policy making for the links between urban environments and health, as also learnt from the COVID-19 pandemic. Collaboration between urban planning and public health is therefore critical for enhancing the capabilities of a city to promote the well-being of its people. However, what leverage potential for urban health can be found in existing plans, policies, and strategies that address urban health? Starting from the relationship between urban systems and health issues, the purpose of this contribution is to broaden the systemic knowledge of urban systems and health so as to try to figure out the impact potential of local urban governance on public health. Considering the systemic nature of health issues, as defined by the World Health Organisation, this is done through a systems thinking epistemological approach. Urban health proposals are studied and assessed in four European cities (Copenhagen, London, Berlin, and Vienna). Current criticalities are found, starting from the guiding goal of such proposals, yet a systemic approach is suggested aimed at supporting and evaluating lasting and healthy urban planning and management strategies.

scholarly journals Population changes in former voivodeship cities in Poland in the context of suburbanization processes and loss of the administrative function

2019 ◽  
Vol 7 (3) ◽  
pp. 66-78 ◽  
Author(s):  
Wioletta Szymańska ◽  
Tomasz Michalski
Keyword(s):  
Demographic Factors ◽  
Administrative Reform ◽  
The Other ◽  
Urban Systems ◽  
Population Changes ◽  
Influence Zone ◽  
City Core ◽  
The Impact ◽  
The City

Abstract The article presents an attempt to analyse population changes and to measure the strength of the impact of factors causing these changes in former voivodeship (province) cities in Poland. In view of the ongoing processes of suburbanisation, the discussion also concerns the areas surrounding the city, i.e. those creating urban systems together with the city. These zones were delineated, calling them demographic influence zones, because only demographic factors were involved in defining them. The research was conducted in the period between1999–2015, and took into account the administrative reform of the country that degraded 31 cities from voivodeship (NUTS-2) capitals to poviat (LAU-1) cities. The main aim of the study was to find an answer to the question: do the directions and the strength of population changes confirm a hypothesis of the destructive impact of the loss of administrative function on settlement units. The results of the study only partially confirmed this hypothesis. Although a decrease in the population is overwhelmingly predominant in the city core, in the case of the demographic influence zone, it has already increased. Counting both parts together, it was found that in half of the cases there was a decline and in the other half a growth of the population.

scholarly journals Modeling the Impact of Electric Vehicle Charging Infrastructure on Regional Energy Systems: Fields of Action for an Improved e-Mobility Integration

Energies ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 7992
Author(s):  
Dominik Husarek ◽  
Vjekoslav Salapic ◽  
Simon Paulus ◽  
Michael Metzger ◽  
Stefan Niessen
Keyword(s):  
Peak Reduction ◽  
Charging Infrastructure ◽  
Infrastructure Networks ◽  
Charging Station ◽  
Electric Vehicle Charging ◽  
Economic Framework ◽  
Infrastructure Investments ◽  
Grid Operators ◽  
The Impact ◽  
Charging Demand

Since e-Mobility is on the rise worldwide, large charging infrastructure networks are required to satisfy the upcoming charging demand. Planning these networks not only involves different objectives from grid operators, drivers and Charging Station (CS) operators alike but it also underlies spatial and temporal uncertainties of the upcoming charging demand. Here, we aim at showing these uncertainties and assess different levers to enable the integration of e-Mobility. Therefore, we introduce an Agent-based model assessing regional charging demand and infrastructure networks with the interactions between charging infrastructure and electric vehicles. A global sensitivity analysis is applied to derive general guidelines for integrating e-Mobility effectively within a region by considering the grid impact, the economic viability and the Service Quality of the deployed Charging Infrastructure (SQCI). We show that an improved macro-economic framework should enable infrastructure investments across different types of locations such as public, highway and work to utilize cross-locational charging peak reduction effects. Since the height of the residential charging peak depends up to 18% on public charger availability, supporting public charging infrastructure investments especially in highly utilized power grid regions is recommended.

scholarly journals Impact of Earthquakes on the Transportation Infrastructure of Indonesia: A Preliminary Study

2019 ◽  
Vol 21 (1) ◽  
pp. 19-28 ◽  
Author(s):  
Anita Amirsardari ◽  
Massoud Sofi ◽  
Elisa Lumantarna ◽  
Iswandi Imran ◽  
Colin Duffield
Keyword(s):  
Risk Assessment ◽  
Seismic Risk ◽  
Transportation Infrastructure ◽  
Seismic Region ◽  
The Past ◽  
Preliminary Study ◽  
Critical Components ◽  
Future Work ◽  
The Impact ◽  
Economical Losses

Indonesia is a high seismic region and one of the most vulnerable countries prone to experiencing damaging earthquakes. It is critical that lifeline infrastructure remain operational or is quickly remediated after an earthquake to minimise physical, social, and economical losses. Not much work has been carried out in understanding the effect of earthquakes on transportation infrastructure systems. This study aims to gain a better understanding of the impact of earthquakes on the transportation infrastructure in Indonesia. This is achieved by firstly reviewing the frameworks and tools for conducting seismic risk assessment of lifeline infrastructure. The critical components of the transportation system are then identified. Various forms of transportation infrastructure damage caused by earthquakes are discussed. An overview of the damaging earthquakes for the past 20 years is presented. Finally, conclusions and recommendations are provided about the future work required for conducting risk assessment of the transportation infrastructure in Indonesia

scholarly journals How Web Shops Impact Consumer Behavior?

2021 ◽  
Vol 15 (3) ◽  
pp. 350-356
Author(s):  
Helena Štimac ◽  
Ivan Kelić ◽  
Karla Bilandžić
Keyword(s):  
Multivariate Analysis ◽  
Linear Regression ◽  
Correlation Analysis ◽  
Reliability Analysis ◽  
Online Shopping ◽  
Customer Behavior ◽  
Descriptive Statistics ◽  
Firm Reputation ◽  
Marketing Actions ◽  
The Impact

The behavior of e-customers is quite unpredictable, which raises additional questions about this topic. The purpose of the paper is to conduct research on e-customers, understand the impact of marketing actions on e-customer behavior and understand the unpredictability of e-customers. Research was conducted on the Mlinar web shop that sells cakes. 284 respondents/buyers had the opportunity to solve questionnaires about behavior after purchase and consumption of product. Different methods have been used in the analysis - descriptive statistics, multivariate analysis (reliability analysis, correlation analysis and linear regression) and analysis of variance (ANOVA). The results showed that most examinees were satisfied with online shopping on the Mlinar web shop and that they are impulsive when online shopping. Saving time is the main reason to buy on a web shop. Research proved that variables such as firm reputation/perceived value, e-satisfaction and online services positively affect the creation of e-loyalty in their users.

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