In an urban environment, sewer flooding and combined sewer overflows (CSOs) are a potential risk to human life, economic assets and the environment. To mitigate such phenomena, real time control systems represent a va...
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In an urban environment, sewer flooding and combined sewer overflows (CSOs) are a potential risk to human life, economic assets and the environment. To mitigate such phenomena, real time control systems represent a valid and cost-effective solution. This paper proposes an urban drainage network equipped by sensors and a series of electronically movable gates controlled by a decentralized real-time system based on a gossip-based algorithm which exhibits good performance and fault tolerance properties. The proposal aims to exploit effectively the storage capacity of the urban drainage network so as to reduce flooding and CSO. The approach is validated by considering the urban drainage system of the city of Cosenza (Italy) and a set of extreme rainfall events as a testbed. Experiments are conducted by using a customized version of the SWMM simulation software and show that the CSO and local flooding volumes are significantly reduced.
We study randomized gossip-based processes in dynamic networks that are motivated by information discovery in large-scale distributed networks such as peer-to-peer and social networks. Awell-studied problem in peer-to...
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We study randomized gossip-based processes in dynamic networks that are motivated by information discovery in large-scale distributed networks such as peer-to-peer and social networks. Awell-studied problem in peer-to-peer networks is resource discovery, where the goal for nodes (hosts with IP addresses) is to discover the IP addresses of all other hosts. Also, some of the recent work on self-stabilization algorithms for P2P/overlay networks proceed via discovery of the complete network. In social networks, nodes (people) discover new nodes through exchanging contacts with their neighbors (friends). In both cases the discovery of new nodes changes the underlying network new edges are added to the network - and the process continues in the changed network. Rigorously analyzing such dynamic (stochastic) processes in a continuously changing topology remains a challenging problem with obvious applications. This paper studies and analyzes two natural gossip-based discovery processes. In the push discovery or triangulation process, each node repeatedly chooses two random neighbors and connects them (i. e., "pushes" their mutual information to each other). In the pull discovery process or the two-hop walk, each node repeatedly requests or "pulls" a random contact from a random neighbor and connects itself to this two-hop neighbor. Both processes are lightweight in the sense that the amortized work done per node is constant per round, local, and naturally robust due to the inherent randomized nature of gossip. Our main result is an almost-tight analysis of the time taken for these two randomized processes to converge. We show that in any undirected n-node graph both processes take O(n log(2) n) rounds to connect every node to all other nodes with high probability, whereas Omega(n log n) is a lower bound. We also study the two-hop walk in directed graphs, and show that it takes O(n(2) log n) time with high probability, and that the worst-case bound is tight for arbitrary dir
We introduce a new distributed eigensolver (dOI) for square matrices based on orthogonal iteration. In contrast to standard parallel eigensolvers, our approach performs only nearest neighbor communication and provides...
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ISBN:
(纸本)9780769549392;9781467353212
We introduce a new distributed eigensolver (dOI) for square matrices based on orthogonal iteration. In contrast to standard parallel eigensolvers, our approach performs only nearest neighbor communication and provides much more flexibility with respect to the properties of the hardware infrastructure on which the computation is performed. This is achieved by utilizing distributed summation methods with randomized communication schedules which do not require global synchronization across the nodes. Our algorithm is particularly attractive for loosely coupled distributed networks with arbitrary network topologies and potentially unreliable components. Our distributed eigensolver dOI is based on a novel distributed matrix-matrix multiplication algorithm and on an extension of a distributed QR factorization algorithm proposed earlier. We illustrate the advantages of dOI in terms of higher flexibility with respect to the underlying network and lower communication cost compared to a related distributed eigensolver by Kempe and McSherry. Moreover, we experimentally illustrate how the overall communication cost of dOI is further reduced by adapting the accuracy of each distributed summation during the orthogonal iteration process.
The real-time control (RTC) system is a valid and cost-effective solution for urban stormwater management. This paper aims to evaluate the beneficial effect on urban flooding risk mitigation produced by applying RTC t...
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The real-time control (RTC) system is a valid and cost-effective solution for urban stormwater management. This paper aims to evaluate the beneficial effect on urban flooding risk mitigation produced by applying RTC techniques to an urban drainage network by considering different control configuration scenarios. To achieve the aim, a distributed real-time system, validated in previous studies, was considered. This approach uses a smart moveable gates system, controlled by software agents, managed by a swarm intelligence algorithm. By running the different scenarios by a customized version of the Storm Water Management Model (SWMM), the findings obtained show a redistribution of conduits filling degrees, exploiting the whole system storage capacity, with a significant reduction of node flooding and total flood volume.
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