Albert Alonso

Postdoc, Aalborg University · Spatio-temporal Modelling & Probabilistic Machine Learning

aadlf@cs.aau.dk

Lonso, Alberta

I'm a postdoc at Aalborg University (2026–present), working on landscape modelling and uncertainty quantification as part of the DK-Future project.

Previously, I was at the IMAGE section at DIKU (2025–2026), working on explainable AI and medical image segmentation.

I did my PhD in Biophysics at the Niels Bohr Institute (2022–2025) as part of the Kirkegaard Lab. My dissertation, Mind the Gradient, explored differentiable methods for studying microorganism behaviour and optimality in biological systems.

I am a co-founder of phaige (2026–present), a startup working on optimising phage isolation to make it a practical alternative to antibiotics.

I also build open-source tools, mostly in JAX. Always open to ideas and collaborations.

Google Scholar | ORCID | GitHub | Looking for Lonso, Alberta? Here you go.

Research

Biophysics & Statistical Physics Computer Vision Probabilistic Modelling
2026
Probabilistic land-use forecast
Beyond accuracy in land-use modeling
A probabilistic reformulation of demand-driven land allocation
Land-use forecasts usually hand you a single map as the future, but these systems are noisy and rarely set in stone. We take a standard demand-driven model and make it probabilistic. The ensemble becomes a trust layer over the usual map. And once you carry that uncertainty downstream, the very same map can look rock-solid or shaky depending on what you measure.
Cost of sensing
Energetic costs of reaching the physical limits of sensing
Sensing a chemical gradient means absorbing molecules, and absorbing molecules costs energy. So how much must a cell burn to sense well? We derive nice closed-form relations tying gradient-sensing accuracy to entropy production, and find a happy surprise: cells can get most of the way to peak chemotaxis while paying only a tiny fraction of the full diffusion-limited cost. I guess precision is cheap, but perfection is not.
Observer-absorber assemblies
Limits of cell sensing in observer-absorber assemblies
A lonely cell senses better by absorbing molecules, which kills off rebinding correlations. That we know. But in a colony, every molecule you absorb is one your neighbour can't. We introduce an observer-absorber model that smoothly interpolates between Berg-Purcell monitoring and perfect absorption, and show the best strategy depends on geometry with Pareto fronts emerging from the tug-of-war.
rNCA self-repairing segmentation
rNCA: Self-repairing segmentation masks
Biological organisms have developed extraordinary capabilities to fix broken structures. We exploit that and construct a cellular-automata network to fix common issues on pixel-wise segmentation masks, resulting in a surprisingly effective method that efficiently repairs topological artifacts in medical segmentation models.
Extremal contours
Extremal contours: Gradient-driven contours for compact visual attribution
We introduce a new explainability mask where a closed contour 'relaxes' on top of the object that the Neural Network is basing its decision on. The cool part is that we move the contour by propagating the gradients through the network and the masking process. Very simple and elegant.
2025
Spline refinement with differentiable rendering
Sometimes predicted centerlines look slightly off. We introduce a training-free differentiable rendering approach to spline refinement, achieving both high reliability and sub-pixel accuracy. It serves as a drop-in replacement for the popular active contour model.
Adaptive nodes
Adaptive node positioning in biological transport networks
When the hydrodynamic graph model accounts for the energy cost of delivery from node to area, we can apply automatic differentiation to study optimal node positions. Curiously, when the domain is irregular (as in leaves), nodes distribute themselves to maximise efficiency.
Receptor clustering
Local clustering and global spreading of receptors for optimal spatial gradient sensing
Tiny cells have a hard time sensing their environment due to physical limits. We present a theoretical model exploring how receptors should be placed for optimal information processing. Results show clustering in high-curvature membrane regions, aligning with real-cell observations.
Pseudopod splitting
Persistent pseudopod splitting is an effective chemotaxis strategy in shallow gradients
Decision making is hard for microscopic cells, yet essential for survival. We present a minimal model providing quantitative understanding of how cells use pseudopod splitting to achieve high-performance chemotaxis with minimal regulation—mechanical intelligence.
Irreversibility in non-reciprocal chaotic systems
A stochastic-thermodynamic framework analysing the relationship between irreversibility and dynamical behaviour in high-dimensional chaotic systems.
2024
ChemoXRL
Learning optimal integration of spatial and temporal information in noisy chemotaxis
Two main chemotaxis strategies exist in nature: temporal (for small cells) and spatial (for larger cells). We show the transition is continuous and a combined strategy outperforms constrained variants.
2023
DeepTangle
Fast detection of slender bodies in high-density microscopy data
An end-to-end deep learning approach for extracting precise shape trajectories of motile, overlapping slender bodies in high-density microscopy, applied to swimming nematodes.

PhD Thesis

Mind the Gradient: Differentiable computational methods in microorganism behaviour studies
Uses differentiable programming techniques to develop computational methods and mathematical models exploring navigation, sensory integration, and behavioural adaptations under physical constraints of the microscopic scale.

Software

  • Bayex – Bayesian Optimisation in JAX stars
  • PCAx – Differentiable PCA in JAX stars
  • t-SNEx – Minimal t-SNE in JAX stars
  • BoundVor – Bounded Voronoi Tessellation stars
  • Notata – Scientific Logging stars

See my GitHub for more details.