1,720,970 research outputs found
Graph models of network behavior in environmental planning
No full textPolicies to protect the environment in Europe and in the rest of the world have been adjusted to take into account the network behavior of conglomerates of nature protection areas. Network behavior can emerge from the natural configuration of habitat patches, or be induced by the establishment of habitat corridors. Careful planning is required to protect and improve the network behavior in existing sites; this has prompted researchers to build graph models of ecological networks, and apply complex network analysis to improve the understanding of their features. However, the most common approach is to keep the focus on a single species, meant to be representative of most species within the area under analysis, or especially important with respect to conservation issues. In this paper, data pertaining to land use types found within sites making up the "Natura 2000" ecological network is used to provide a high-level view of the network, and propose a framework for study, in which similarity measures are used as a criterion to suggest guidelines for land management
Evaluating complex network indices for vulnerability analysis of a territorial power grid
No full textIn order to meet power demands in a sustainable way, power grids are gradually being adjusted to fit into a smart grid paradigm. A common problem in this kind of transition is to identify locations where it is most beneficial to invest in distributed generation. In order to assist in such a decision, we work on a graph model of a regional power grid. We apply optimization strategies on power flows, and verify the current degree of self-sufficiency of the network, with special reference to the effect of natural variations in wind-based production. We propose a method to assess collateral damage to the network resulting from a localized failure, and proceed to perform complex network analysis on multiple instances of the network, looking for correlations between estimated damages and betweenness centrality indices, with the purpose of attempting to determine which model is best suited to predict features of our network
Complex network based approaches to enable software-aided management and planning
No full textSoftware tools to perform complex network analysis can be a valuable help in decision making for infrastructure development plans and environmental planning. However, it is necessary to build a data model of a region, including elements such as cities, geographical features and protected areas, and representing constraints where applicable, like in the case of defining ecological corridors. The issue of building a model to enable computation at a desirable level of abstraction is nontrivial. We discuss different models to represent a region as a network, in order to enable analysis based on techniques derived from graph theory, complex network theory, and operational research. In doing so, we highlight the advantages and disadvantages of different approaches to this problem
Modelli funzionali delle reti ecologiche: dal particolare al generale
Full text linkLa protezione degli habitat e delle specie a rischio avviene oggi in Europa attraverso l'istituzione del progetto Natura 2000. La caratteristica principale di Natura 2000 è il comportamento reticolare delle aree protette, il quale deve emergere da una gestione del territorio che avviene in ambito locale, le cui finalità non si limitino alla protezione di uno specifico habitat, ma si integrino con obiettivi di larga scala e di lungo periodo. La rete Natura 2000 è frequentemente oggetto di studio con tecniche derivate dalla teoria delle reti complesse, tuttavia nella maggior parte dei casi i modelli matematici utilizzati per rappresentare la rete tengono conto solamente di una specie scelta come obiettivo, o un insieme limitato di specie. La ricerca di un modello che catturi il comportamento reticolare della rete in senso più generale può passare attraverso l'integrazione tra i dati raccolti per aree protette diverse, oltre a quella con dati provenienti da altre fonti; integrazione necessaria poiché i dati sulla rete Natura 2000 provengono da attività di rilevamento operate sul territorio e si intendono riferite a singole aree protette, sebbene talora assai vaste. Questo lavoro, considerando come caso di studio i siti della Regione Sardegna, mira alla generazione di modelli funzionali della rete ecologica, tramite l'integrazione dei dati raccolti dai rilevatori nell'ambito del progetto Natura 2000 con i dati sull'uso del suolo, operata tramite software GIS, e conseguentemente allo studio delle proprietà della rete risultante con la teoria delle reti complesse. Questa nuova tipologia di modello risulta utile per il confronto con modelli relativi a singole specie, allo scopo di valutare la portata delle modificazioni conseguenti a interventi proposti sul territorio.The protection of endangered habitats and species is coordinated in Europe under the project denominated Natura 2000. The main aspect of this project is the notion that nature protection areas are considered part of an ecological network, and they have to be established and maintained while taking into account a number of large-scale goals, especially concerning the protection of biodiversity. The Natura 2000 network has frequently been an object of study using complex network analysis, but in most cases, the graph models under analysis are built considering only a single species or a very limited set of species. In an endeavour toward a graph model with a higher degree of generality, the data sources that are part of the project should be integrated with external sources, as within the Natura 2000 project, no information is collected on territories outside nature protection areas. This paper aims at building general graph models by cross-referencing land use data with the employment of GIS software, and providing guidelines to the analysis of these models using complex network analysis techniques. The proposed models can be useful to make comparisons with single-species models and perform the assessment of proposed network modifications
A model of assessment of collateral damage on power grids based on complex network theory
Full text linkAs power grids are gradually adjusted to fit into a smart grid paradigm, a common problem is to identify locations where it is most beneficial to introduce distributed generation. In order to assist in such a decision, we work on a graph model of a regional power grid, and propose a method to assess collateral damage to the network resulting from a localized failure. We perform complex network analysis on multiple instances of the network, looking for correlations between estimated damages and betweenness centrality indices, attempting to determine which model is best suited to predict features of our network
Topological and conceptual complex network models for environmental planning
Full text linkThe growing importance of environmental planning has encouraged researchers to apply complex network analysis on topological models of environmental networks. Relevant features of current green infrastructure can be derived with common and ad hoc techniques, but results tend to expose only a limited view, whether by geographical areas or by species. In this paper, the possibility to extend complex network analysis to conceptual models with a higher degree of abstraction is explored
An Analysis of Features and Tendencies in Mobile Banking Apps
No full textMobile devices such as smartphones and tablets are being employed alongside personal computers, and even replacing them in some applications. Banks are increasingly investing on mobility, by enabling the mobile web and mobile app channels for online banking, and by providing new mobile payment services. In this paper, the services for off-branch banking offered by several Italian banks are analyzed, showing that mobile apps have surpassed the mobile web channel in completeness of the offer, due to the fact that additional capabilities of mobile devices make possible advanced features and applications. An outlook on the near future is provided, remarking that mobile marketing and mobile recommender systems can greatly take advantage of being run natively on devices, making it desirable for businesses to invest on designing mobile apps
Performance analysis and grid computing on wide area
No full textNowadays, the energy production system is no longer suitable to our livelihood and several issues need to be solved. Primary sources will not last forever and the environmental impact that we have on the planet grows more each year. Even renewable energies, always considered as part of the solution, are not stable enough to substitute or significantly integrate our traditional system. The research on smart grid is now seen as the best opportunity to overcome these problems. These new field proposes the realization of an intelligent grid equipped with sensors and devices able to constantly monitor demand and supply of the electrical grid. This architecture will be able to direct energy only where and when it is needed, avoiding waste and improving power quality at the same time. We give a short recap about grid proprieties and challenges, and then propose an approach based on complex network to study the real case model of a regional power. We comment all the design choices adopted during the model construction, pointing out the importance of using appropriate weights to define connections between substations, in order to represent the behavior of the grid properly. We show, through an example, how the betweenness can change employing different cost settings and finally lay the foundation for a future work
Connectivity analysis of ecological landscape networks by cut node ranking
Full text linkEcological landscape networks represent the current paradigm for the protection of biodiversity. In the analysis of land features that precedes the establishment of land management plans, graph-theoretic approaches become increasingly popular due to their aptness for the representation of connectivity. Ecological corridors, seen as connecting elements for geographically distant areas dedicated to the preservation of endangered species, can be analyzed for the identification of critical land patches, by ranking cut nodes according to a score that encompasses various criteria for prioritized intervention
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