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- Modelling forest fires using complex networksPublication . Perestrelo, Sara; Grácio, Clara; Almeida Ribeiro, Nuno; Lopes, LuísForest fires have been a major threat to the environment throughout history. In order to mitigate its consequences, we present, in a first of a series of works, a mathematical model with the purpose of predicting fire spreading in a given land portion divided into patches, considering the area and the rate of spread of each patch as inputs. The rate of spread can be estimated from previous knowledge on fuel availability, weather and terrain conditions. We compute the time duration of the spreading process in a land patch in order to construct and parametrize a landscape network, using cellular automata simulations. We use the multilayer network model to propose a network of networks at the landscape scale, where the nodes are the local patches, each with their own spreading dynamics. We compute some respective network measures and aim, in further work, for the establishment of a fire-break structure according to increasing accuracy simulation results.
- Modelling spreading process of a wildfire in heterogeneous orography, fuel distribution and environmental conditions - a complex networks approachPublication . Perestrelo, Sara; Grácio, Maria; Ribeiro, Nuno; Lopes, LuísForest fires are phenomena that represent a great danger for the population and have severe environmental consequences. The greatest efforts in regard to direct confrontation require a large investment in terms of both financial and human resources, partly due to the unpredictability of fire behaviour and the fuel distribution that feeds its growth and spread. To deal with this unpredictability in a more efficient manner, our work focuses around the establishment of an optimal fire-break structure whose purpose is to block the spread along the landscape, at a minimal cost. It’s a preventative approach, which acts as a complement to direct confrontation and contributes to the reduction of material, economic and human losses. For the establishment of this optimal fire-break structure it is necessary to model fire spreading process and, for that, we use the multilayer network model, within the area of complex networks. We aim the construction of a network of networks that allows us to simulate the fire spreading process both at a local scale and at a more global scale.
- A multi-scale network with percolation model to describe the spreading of forest firesPublication . Perestrelo, Sara; C., Grácio; Almeida Ribeiro, Nuno; Lopes, LuísForest fires have been a major threat to forest ecosystems and its biodiversity, as well as the environment in general, particularly in the Mediterranean regions. To mitigate fire spreading, this study aims at finding a fire-break solution for territories prone to fire occurrence. To the effect, here follows a model to map and predict phase transitions in fire regimes (spanning fires vs. penetrating fires) based on terrain morphology. The structure consists of a 2-scale network using site percolation and SIR epidemiology rules in a cellular automata to model local fire Dynamics. The target area for the application is the region of Serra de Ossa in Portugal, due to its wildfire incidence. The study considers the cases for a Moore neighbourhood of warm cells of radius 1 and 2 and also considers a heterogeneous terrain with 3 classes of vegetation. Phase transitions are found for different combinations of fire risk for each of these classes and use these values to parametrize the resulting landscape network.