Complex networks and data analysis
Many real-world systems, constituted by nonlinear interacting units, are modelled by complex networks (or graphs) in which the nodes represent the units and the links represent the interactions among them. These interactions are often only partially known, and we are interested in developing appropriated tools for inferring the network structure, from observed data. Typically, only limited (and noisy) data is available. We are also interested in extracting additional information about underlying phenomena, from observed data (for the identification of regime transitions, for uncovering the community structure of highly inter-related nodes, etc.).
We apply advanced data analysis tools to two types of empirical data:
-climatological time-series: we use the network approach and various data analysis tools (ordinal analysis, Hilbert analysis) to investigate long-range climatic interactions (inferring the underlying “climate network”) and signatures of regime transitions that can be related to “climate change”.
- biomedical images: we use symbolic analysis (2D extension of ordinal analysis) and the network approach (by mapping a 2D image into a graph) to develop novel tools for image classification. We analyze ocular images with the goal of providing new measures for automatic/unsupervised classification. We also aim at providing reliable early-warning indicators of ocular diseases such as glaucoma.
D. A. Zappala, M. Barreiro, and C. Masoller
Earth System Dynamics 9, 383 (2018). Supplementary information
G. Tirabassi, L. Sommerlade, and C. Masoller, Chaos (2017). Arxiv
T. A. Schieber, L. Carpi, A. Diaz-Guilera, P. M. Pardalos, C. Masoller, and M. G. Ravetti, Nat. Comm. 8, 13928 (2017).
F. Arizmendi, M. Barreiro, C. Masoller, Sci. Rep. 7, 45676 (2017).
D. A. Zappalà, M. Barreiro, and C. Masoller, Entropy 18, 408 (2016).
G. Tirabassi and C. Masoller, Scientific Reports 6, 29804 (2016).
G. Tirabassi, R. Sevilla-Escoboza, J. M. Buldú and C. Masoller, Scientific Reports 5 10829 (2015).
J. I. Deza, M. Barreiro and C. Masoller, Chaos 25, 033105 (2015). Video
C. Masoller, Y. Hong, S. Ayad, F. Gustave, S. Barland, A. J. Pons, S. Gómez and A. Arenas, New Journal of Physics 17, 023068 (2015).
G. Tirabassi, C. Masoller and M. Barreiro,International Journal of Climatology 35, 3440 (2015).
Ignacio Deza: Climate networks constructed by using information-theoretic measures and ordinal time-series analysis (February 2015)
Giulio Tirabassi: Disentangling climate interactions and inferring tipping points by using complex networks (June 2015)
Complex physical and biophysical systems (ComPhysBio, FIS2015-66503-C3-2-P)
Click on the image to download the paper
Quantifying changes in surface air temperature dynamics during the last 30 years (Earth System Dynamics 2018).
Quantifying network dissimilarities (Nat. Comm. 2017)
Identying regions with nonlinear surface air temperature response to solar forcing (Sci. Rep. 2017)