Reader
- About
-
- Email Address
- murilo.baptista@abdn.ac.uk
- Telephone Number
- +44 (0)1224 272489
- Office Address
University of Aberdeen
Institute for Complex Systems and Mathematical Biology
Meston Building, Meston Walk
Aberdeen AB24 3UE
- School/Department
- School of Natural and Computing Sciences
Biography
Since 2014, I am a Reader of the University of Aberdeen, having joined it in 2009 as a Senior Lecturer. Before that, I worked as a postdoc, guest scientist, or guest assistant professor at 5 Universities and Institutes in USA, Brazil, Germany, and Portugal. I have interest in understanding the relationship among function (e.g., information, collective behaviour and synchronisation) and structure in large networked complex systems for its posterior modelling, having contributed to works in neuroscience, smart engineering systems, and sustainability of the Earth. My work is supported by analytical developments, but I also rely on the analysis and modelling of data using techniques from data sciences, nonlinear time-series analysis, and machine learning. I am a leading scientist in the area of chaos-based communication, where I am working to show that chaos offers alternative technologies for efficiently smart (and secure) wireless communication systems.
- Research
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Research Overview
I have interest in understanding the relationship among function (e.g., information, collective behaviour and synchronisation) and structure in large networked complex systems for its posterior modelling, having contributed to works in neuroscience, smart engineering systems, and sustainability of the Earth. My work is supported by analytical developments, but I also rely on the analysis and modelling of data using techniques from data sciences, nonlinear time-series analysis, and machine learning. I am a leading scientist in the area of chaos-based communication, where I am working to show that chaos offers alternative technologies for efficiently smart (and secure) wireless communication systems.
Research Areas
Accepting PhDs
I am currently accepting PhDs in Physics, Maths, Engineering.
Please get in touch if you would like to discuss your research ideas further.
Research Specialisms
- Mathematical Modelling
- Applied Mathematics
- Dynamics
- Information Technology
- Neural Computing
Our research specialisms are based on the Higher Education Classification of Subjects (HECoS) which is HESA open data, published under the Creative Commons Attribution 4.0 International licence.
Current Research
I am working to understand optimal configuration to communicate wirelessly with chaos in the air and in space, to model synapses and their information capacity, predict degradation in vessels, to understand how synchronisation emerges in networks with connections of higher order, to model how arguments in a networks of agents predominates, to understand the causal relationship of socio and economic variables in Brazil, to explain the topological changes suffered in the brain of patients that have undergone brain surgeries due to tumours.
Past Research
During my PhD, we discovered that the driven Chua’s chaotic circuit presented a transition to chaos via destruction of a two-frequency torus. Though this route was known, the description of topological changes suffered by the chaotic attractor was not. Later on, I work to define the phase of chaotic oscillators. Though the phase of a periodic signal is a well-known quantity, for chaotic trajectories, it is not. Our work has proposed a mathematical framework to define and measure it.
To secure communication systems based on chaos, the chaotic wave signal encoding information should not be transmitted. Instead, one could transmit the trajectory’s Poincaré first return times (PFRT). This understanding resulted in the cipher today one of the founding references for the area of chaos-based cryptography. We have proved (see http://hdl.handle.net/10216/65184) a conjecture that the distribution of PFRTs can be analytically calculated by the eigenvalues of the unstable periodic orbits of the chaotic attractor, and shown that a very important and popular quantity to characterise chaotic behaviour - the Kolmogorov-Sinai entropy – can be estimated from PFRTs.
Typically, chaotic behaviour in a nonlinear system is replaced by periodic behaviour even when arbitrarily small parameter alterations are made. I worked on experiments to demonstrate this and validate works that explain why periodic behaviour is ubiquitous in nature, came in Ref. [42,90].
My work in neural networks with neurons connected by both electrical and chemical synapses has provided a rigorous ground to explain the regulatory effect that electrical synapses have in the brain. The study of such networks, known as multiplex networks, only became a topic of attention by the scientific community by 2013. We have proposed a formula for the mutual information in terms of Lyapunov exponents (that quantify chaos) and used to provide support for the Infomax theory that suggests that the brain evolve by maximising information. We have discovered the phenomenon of Collective Almost Synchronization, ubiquitous in complex networks, and that has been shown to be crucial for the chaos enhancement of machine learning methods to model and predict EEG signals. I have also shown that the cause-effect relationship between variables, or causality (and that is usually characterised by temporal quantities), is a spatial-temporal phenomenon. Finally, we have shown that a power grid without control systems can be designed to be reliable by properly connecting generators and consumers.
- Publications
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Page 3 of 7 Results 51 to 75 of 171
Mirror node correlations tuning synchronization in multiplex networks
Physical Review. E, Statistical, Nonlinear and Soft Matter Physics, vol. 96, no. 6, 062301Contributions to Journals: ArticlesInterpreting Physical Flows in Networks as a Communication System
Indian Academy of Sciences Conference Series, vol. 1, no. 1, pp. 17-23Contributions to Journals: ArticlesSynaptic Plasticity and Spike Synchronisation in Neuronal Networks
Brazilian Journal of Physics, vol. 47, no. 6, pp. 678-688Contributions to Journals: Articles- [ONLINE] DOI: https://doi.org/10.1007/s13538-017-0529-5
- [OPEN ACCESS] http://aura.abdn.ac.uk/bitstream/2164/11099/1/Review_BJP.pdf
Methods for removal of unwanted signals from gravity time-series: comparison using linear techniques complemented with analysis of system dynamics
Chaos, vol. 27, no. 10, pp. 1-12Contributions to Journals: Articles- [ONLINE] DOI: https://doi.org/10.1063/1.4996452
- [OPEN ACCESS] http://aura.abdn.ac.uk/bitstream/2164/9507/1/article_1_.pdf
- [OPEN ACCESS] http://aura.abdn.ac.uk/bitstream/2164/9507/3/1.4996452.pdf
Uncovering hidden flows in physical networks
Europhysics Letters, vol. 118, no. 5, pp. 1-7Contributions to Journals: ArticlesA chaotic spread spectrum system for underwater acoustic communication
Physica. A, Statistical Mechanics and its Applications, vol. 478, pp. 77-92Contributions to Journals: Articles- [ONLINE] DOI: https://doi.org/10.1016/j.physa.2017.02.036
- [OPEN ACCESS] http://aura.abdn.ac.uk/bitstream/2164/10106/1/template20170128.pdf
General analytical solutions for DC/AC circuit-network analysis
The European Physical Journal. Special Topics, vol. 226, no. 9, pp. 1829-1844Contributions to Journals: ArticlesSensitive Dependence on Parameters of Continuous-time Nonlinear Dynamical Systems
Chaos, Solitons & Fractals, vol. 99, pp. 16-19Contributions to Journals: Articles- [ONLINE] DOI: https://doi.org/10.1016/j.chaos.2017.03.043
- [OPEN ACCESS] http://aura.abdn.ac.uk/bitstream/2164/10251/1/medeirosCSF.pdf
Synchronised firing patterns in a random network of adaptive exponential integrate-and-fire neuron model
Neural Networks, vol. 90, pp. 1-7Contributions to Journals: Articles- [ONLINE] DOI: https://doi.org/10.1016/j.neunet.2017.03.005
- [OPEN ACCESS] http://aura.abdn.ac.uk/bitstream/2164/10191/1/AEIF_NN_new.pdf
Optimization of synchronizability in multiplex networks by rewiring one layer
Physical Review. E, Statistical, Nonlinear and Soft Matter Physics, vol. 95, no. 4, pp. 1-5Contributions to Journals: Articles- [ONLINE] DOI: https://doi.org/10.1103/PhysRevE.95.040301
- [OPEN ACCESS] http://aura.abdn.ac.uk/bitstream/2164/8468/3/PhysRevE.95.040301.pdf
Maintaining extensivity in evolutionary multiplex networks
PloS ONE, vol. 12, no. 4, e0175389Contributions to Journals: ArticlesSpike timing-dependent plasticity induces non-trivial topology in the brain
Neural Networks, vol. 88, pp. 58–64Contributions to Journals: Articles- [ONLINE] DOI: https://doi.org/10.1016/j.neunet.2017.01.010
- [OPEN ACCESS] http://aura.abdn.ac.uk/bitstream/2164/9971/1/STDP_NN_new.pdf
Tumour chemotherapy strategy based on impulse control theory
Philosophical Transactions of the Royal Society A: Mathematical, Physical & Engineering Sciences, vol. 375, no. 2088, 20160221Contributions to Journals: Articles- [ONLINE] DOI: https://doi.org/10.1098/rsta.2016.0221
- [OPEN ACCESS] http://aura.abdn.ac.uk/bitstream/2164/9935/1/Ren_Tumour_2_.pdf
Trapping Phenomenon Attenuates the Consequences of Tipping Points for Limit Cycles
Scientific Reports, vol. 7, 42351Contributions to Journals: ArticlesCharacterization in bi-parameter space of a non-ideal oscillator
Physica. A, Statistical Mechanics and its Applications, vol. 466, pp. 224-231Contributions to Journals: Articles- [ONLINE] DOI: https://doi.org/10.1016/j.physa.2016.09.020
- [OPEN ACCESS] http://aura.abdn.ac.uk/bitstream/2164/9333/1/PhysicaA.pdf
Robustness of Chaos to Multipath Propagation Media
Chaotic Signals in Digital Communications. Eisencraft, M., Attux, R., Suyama, R. (eds.). CRC Press, 15 pagesChapters in Books, Reports and Conference Proceedings: ChaptersSustainable Smart Cities: Applying Complexity Science to Achieve Urban Sustainability
Tokyo: United Nations University Press. 4 pagesBooks and Reports: Other ReportsWeak connections form an infinite number of patterns in the brain
Scientific Reports, vol. 7, 46472Contributions to Journals: ArticlesControl and prediction for blackouts caused by frequency collapse in smart grids
Chaos, vol. 26, no. 9, 093119Contributions to Journals: Articles- [ONLINE] DOI: https://doi.org/10.1063/1.4963764
- [OPEN ACCESS] http://aura.abdn.ac.uk/bitstream/2164/7452/3/1.4963764.pdf
Theoretical knock-outs on biological networks
Journal of Theoretical Biology, vol. 403, pp. 38-44Contributions to Journals: Articles- [ONLINE] http://arxiv.org/pdf/1512.03094
- [ONLINE] DOI: https://doi.org/10.1016/j.jtbi.2016.05.021
- [OPEN ACCESS] http://aura.abdn.ac.uk/bitstream/2164/5379/1/1512.03094v1
Unstable dimension variability structure in the parameter space of coupled Hénon maps
Applied Mathematics and Computation, vol. 286, pp. 23-28Contributions to Journals: Articles- [ONLINE] DOI: https://doi.org/10.1016/j.amc.2016.04.007
- [ONLINE] View publication in Scopus
Experimental Validation of Wireless Communication with Chaos
Chaos, vol. 26, no. 8, 083117Contributions to Journals: Articles- [ONLINE] DOI: https://doi.org/10.1063/1.4960787
- [OPEN ACCESS] http://aura.abdn.ac.uk/bitstream/2164/6311/3/1.4960787.pdf
Parameter space of experimental chaotic circuits with high-precision control parameters
Chaos, vol. 26, no. 8, pp. 1-7Contributions to Journals: Articles- [ONLINE] DOI: https://doi.org/10.1063/1.4960582
- [OPEN ACCESS] http://aura.abdn.ac.uk/bitstream/2164/6255/2/1_2E4960582.pdf
Tilted excitation implies odd periodic resonances
Physical Review. E, Statistical, Nonlinear and Soft Matter Physics, vol. 94, no. 1, pp. 1-6Contributions to Journals: Articles- [ONLINE] DOI: https://doi.org/10.1103/PhysRevE.94.012202
- [OPEN ACCESS] http://aura.abdn.ac.uk/bitstream/2164/6225/1/PRE_final.pdf
Network and external perturbation induce burst synchronisation in cat cerebral cortex
Communications in Nonlinear Science and Numerical Simulation, vol. 34, pp. 45-54Contributions to Journals: Articles- [ONLINE] DOI: https://doi.org/10.1016/j.cnsns.2015.10.009
- [ONLINE] View publication in Scopus