1,721,002 research outputs found
Time‐Varying Input‐Output Inoperability Model
No full textRepresenting interdependent critical infrastructures is mandatory for implementing protection policies and strategies. Among the several interdependency models provided over the years, the input-output inoperability model (IIM) has attracted widespread attention due to its simplicity and compactness. Such a model can emphasize cascading effects induced in a complex scenario by dependencies and interdependencies; however, the model is typically set up based on economic data, and the stationary assumption greatly reduces the applicability of the framework. These aspects are crude approximations due to the intrinsic limits of the methodology. Indeed, in modeling realistic scenarios, the coupling of different infrastructures and sectors is expected to increase with outage duration. In this paper, a different formulation of the IIM is proposed where time-varying interdependency coefficients are considered. Such coefficients are defined to explicitly account for the severity and duration of negative phenomena. Some interesting results are obtained from a complex case study including several infrastructures in Italy, emphasizing the features of the proposed methodology. The proposed framework, based directly on operator experience, captures the behaviors induced by the various backup strategies
Distributed Negotiation for Reaching Agreement among Reluctant Players in Cooperative Multi-Agent Systems
No full textIn this article, we propose a distributed negotiation framework that allows a set of cooperative agents to find a common ground with their neighbors while attempting to modify their initial opinion by the least possible amount. Based on such a framework, we develop a distributed agreement approach where the effort spent in the local agreement reflects the relevance of the agents in a weighted consensus process. In particular, we assume that players whose ideas happen to satisfactory mediate the standpoint of their interlocutors will end-up being more influential in the overall decision-making process. We conclude the article by applying the proposed methodology in the context of distributed data aggregation scenarios, as a way to mitigate the effect of outliers (e.g., faulty sensors).</p
A Sum-of-States Preservation Framework for Open Multi-Agent Systems With Nonlinear Heterogeneous Coupling
Full text linkIn this article, we develop a general open multiagent systems (OMAS) framework over undirected graphs where the agents' interaction is, in general, nonlinear, time-varying, and heterogeneous, in that the agents interact with different pairwise interaction rules for each link, possibly nonlinear, which may change over time. In particular, assuming the agents interact by exchanging flows , which modify their states, our framework guarantees that the sum of the states of agents participating in the network is preserved. To this end, agents maintain a state variable for each of their neighbors. Upon the disconnection of a neighbor, such a variable is used to completely eliminate the effect of previous interaction with disconnected agents from the overall system. In order to demonstrate the effectiveness of the proposed OMAS framework, we provide a case study focused on average consensus, and, specifically, we develop a sufficient condition on the structure of the agents' interaction guaranteeing asymptotic convergence under the assumption that the network becomes fixed. The article is complemented by simulation results that numerically demonstrate the effectiveness of the proposed method
Simultaneous localization and routing in sensor networks using shadow edges
No full textIn the last decade, Wireless Sensor Networks (WSN) have been adopted in a wide range of industrial and consumer applications to perform various monitoring tasks such as search, rescue, disaster relief, target tracking and smart environments control. In many such tasks, node localization is inherently one of the system parameters. Node localization is required to gain spatial awareness of the supervised area. In this work a simultaneous localization and routing algorithm is proposed. The localization is obtained by a ranging technique, exploiting network topology provided by the routing algorithm to reduce the network signaling communication, which is the most power-consuming operation in WSN, as much as possible. To this end, Shadow Edges, a novel class of links, is considered to take into account the lack of communication among nodes
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