Alexandre de Bustamante Simas
Alexandre Simas is an expert on stochastic processes and spatial statistics, with a focus on stochastic partial differential equations and random fields on metric graphs.
Biography
Alexandre Simas is a senior research scientist at KAUST in the Stochastic Processes and Mathematical Statistics group. His work spans probability, statistics and mathematical analysis, with a particular focus on stochastic partial differential equations, random fields on complex domains and statistical methodology for spatial and graph-based data.
He received his Ph.D. in Mathematics from the Instituto Nacional de Matemática Pura e Aplicada (IMPA) in Brazil, and part of his doctoral research was conducted at the Courant Institute of Mathematical Sciences at New York University under the mentorship of S. R. S. Varadhan. Before joining KAUST, Alexandre was a faculty member at the Federal University of Paraíba, where he reached the position of associate professor.
His research includes contributions to the theory and computation of SPDE-based models, Gaussian and non-Gaussian processes, fractional and non-stationary fields, and statistical modeling on metric graphs and manifolds. He is also active in the development of open-source statistical software, co-authoring the MetricGraph, rSPDE and ngme2 packages, among others.
Research Interests
Alexandre’s research focuses on stochastic partial differential equations, probability theory and spatial statistics, with particular emphasis on the mathematical and statistical modeling of Gaussian and non-Gaussian random fields on metric graphs and other complex geometries. His work develops theoretical foundations for SPDE-based models on graph-structured domains, including results on covariance structures, regularity properties and computationally efficient approximation methods.
He also works on Bayesian inference for large-scale SPDE models, fractional and non-stationary fields, and on the construction of flexible statistical frameworks for data defined on networks and irregular spatial domains. In parallel with these theoretical developments, Alexandre contributes to the creation of open-source R software, including the MetricGraph package, the rSPDE package and the ngme2 package, which provide tools for modeling and inference in applications ranging from environmental processes to network-based phenomena.
Awards and Distinctions
- Best paper award, Spatial Statistics: At the Dawn of AI, 2025 , The 7th Spatial Statistics conference, 2025
Education
- Doctor of Philosophy (Ph.D.)
- Mathematics, Instituto Nacional de Matemática Pura e Aplicada, Brazil, 2010
- Doctor of Philosophy (Ph.D.)
- Visiting Student, New York University, United States, 2010
- Bachelor of Science (B.S.)
- Statistics, Federal University of Pernambuco, Brazil, 2005
Quote
“In my work, I seek to combine the rigor of theoretical statistics with the creativity of computational methods to solve real-world problems in data analysis and modeling.”
Selected Publications
- Simas, A. B., & Jhonson, K. (2025). One-sided Measure Theoretic Elliptic Operators and Applications to SDEs Driven by Gaussian White Noise with Atomic Intensity. Potential Analysis, 63, 34. Retrieved from https://link.springer.com/article/10.1007/s11118-025-10208-1 (Original work published 2025)
- Bolin, D., Simas, A. B., & Wallin, J. (2026). Markov properties of Gaussian random fields on compact metric graphs. Bernoulli, 32(1), 26. Retrieved from https://projecteuclid.org/journals/bernoulli/volume-32/issue-1/Markov-properties-of-Gaussian-random-fields-on-compact-metric-graphs/10.3150/25-BEJ1853.full
- Bolin, D., Simas, A. B., & Mehandiratta, V. (2025). Linear cost and exponentially convergent approximation of Gaussian Matérn processes on intervals. Journal of Machine Learning Research, 26(96), 34. Retrieved from https://jmlr.org/papers/v26/24-1779.html
- Leao, D., Ohashi, A., & Simas, A. B. (2018). A weak version of path-dependent functional Itô calculus. Annals of Probability, 46(6), 43. Retrieved from https://projecteuclid.org/journals/annals-of-probability/volume-46/issue-6/A-weak-version-of-path-dependent-functional-It%c3%b4-calculus/10.1214/17-AOP1250.full
- Simas, A. B., & Valentim, F. (2018). Homogenization of generalized second-order elliptic difference operators. Journal of Differential Equations, 265, 45. Retrieved from https://www.sciencedirect.com/science/article/pii/S0022039618302997
