Posts by Collection

portfolio

Abnormal motion from video

Detect, explain, and notify abnormal vessel behavior from video.

Multisensor fusion, mutiple object tracking, anomaly detection

Detecting people in restricted areas and ships not broadcasting their positions with AIS.

Artificial agent learns representative trajectories by imitation

Real vessel trajectory in the Gulf of Mexico. Prediction from an artificial agent.

publications

The cantilevered beam: an analytical solution for general deflections of linear-elastic materials

Published in European Journal of Physics, 2006

As a Bachelor student, I was confronted with studying the bending of cantilever beams in a experimental physics class. After realizing that the theory was incomplete, I exploited the consequences of a proper formulation.

Semi-exact solutions for large deflections of cantilever beams of non-linear elastic behavior

Published in International Journal of Non-Linear Mechanics, 2009

I couldn’t let my Bachelor finish without answering how the corrected bending-moment formulation of cantilever beams that I had discovered could be applied to materials which don’t have a linear elastic response.

Magnetic properties of a ferrimagnetic mixed (1,3/2) spin chain with inhomogeneous crystal-field anisotropy

Published in Journal of Magnetism and Magnetic Materials, 2010

The Master comes with new challenges … and I began to embrace them by fixing my attention on quantum magnetism in low dimensional systems. How else to understand the topic than by starting from simple specific examples?

Interacting spin-wave dispersion relations of ferrimagnetic Heisenberg chains with crystal-field anisotropy

Published in Solid State Communications, 2010

Now it is time to complicate things and study more general cases of spin configurations and interactions. I wanted to lift a controversy regarding the effectiveness of the spin-wave theory when applied to mixed-spin chains with crystal-field anisotropy.

Formation of quantum magnetization plateaux in mixed-spin Ising chains with single-ion anisotropy

Published in Journal of Magnetism and Magnetic Materials, 2010

What I had observed in the (1,3/2) spin chains was too beautiful to leave it unfinished. I couldn’t resist generalizing the methods that I had used to other spin configurations. This time, however, the soup had more ingredients.

Pairwise entanglement and critical behavior of an anisotropic ferrimagnetic spin chain

Published in Physics Letters A, 2011

Entanglement is a weird quantum phenomenon and its relationship with quantum phase transitions is fascinating. Evidently, exploring this connection within the context of mixed-spin systems was the next step.

Unconventional features of the low-temperature properties of a dimerized quantum mixed-spin chain

Published in Physica Status Solidi B, 2011

It is very satisfying when a material has an unexpected behavior and you can find a model which explains it. By swimming in the sea of interesting problems, I found this one … and had a lot of fun realizing what was going on.

Entanglement and quantum phase transition in a mixed-spin Heisenberg chain with single-ion anisotropy

Published in Physica A: Statistical Mechanics and its Applications, 2011

How much can the quantum entanglement within a mixed-spin chain survive when the temperature is increased? In this study, I could figure out means to affect that threshold temperature by varying the crystal-field anisotropy.

Real Time Dynamics of a Spin Chain with Dzyaloshinskii-Moriya Interactions: Spiral Formation and Quantum Spin Oscillations

Published in Physical Review B, 2011

I had studied enough ground-state and finite-temperature properties in spin chains for my thesis. Nevertheless, I felt that something was missing: how the behavior of initial states evolves with time. So I closed the chapter by investigating this for a special case.

Approach to Equilibrium of a Restricted Class of Isolated Quantum Systems After a Quench

Published in arXiv, 2015

At some point during my PhD, I couldn’t reconcile in my mind having isolated quantum systems which, after some initial manipulation, come to equilibrium after a long time. So I looked for sufficient conditions for this to happen, arriving at a very restricted class.

Quantum recurrences in a one-dimensional gas of impenetrable bosons

Published in Physical Review E, 2015

I was captivated by Fano’s formulation of the density matrix as a vector in Liouville space. Using it for the quantum particle in a box problem, I arrived at a novel description of its back-and-forth motion and used it to interpret the quantum Newton’s cradle.

Theory of entropy production in quantum many-body systems

Published in Physical Review B, 2016

In quantum mechanics, we talk about quantum observables as the entities that are measurable. In termodynamics, the entropy is a state variable, as measurable as the temperature and pressure. What is the corresponding quantum observable?

Entropy production and thermalization in the one-atom maser

Published in Physical Review E, 2016

How are thermodynamic phenomena to be interpreted at quantum scales? Failure to do this properly might lead to paradoxes, as in the Jaynes-Cummings discussion of the one-atom maser. This was a suitable testbed for my entropy-production theory.

Chiral phonons and electrical resistivity of ferromagnetic metals at low temperatures

Published in Physica Status Solidi B, 2018

Quantum magnetism comes back! I discovered an old problem related to a linear contribution to the resistivity of ferromagnets around liquid helium temperatures. I showed that this could be due to electrons interacting with chiral phonons.

Can a single neuron learn predictive uncertainty?

Published in Journal of Uncertainty, Fuzziness and Knowledge-Based Systems, 2021

Shortly after beginning my new job as an AI researcher, I got interested in the field of uncertainty estimation in ML models. I noticed that estimating confidence intervals was similar to computing the chemical potential of an electron gas. I then began the journey.

Detection and Geovisualization of Abnormal Vessel Behavior from Video

Published in IEEE International Intelligent Transportation Systems Conference, 2021

Entering the field of anomaly detection using AI, I lead a team to develop a simple mechanism to detect abnormal vessel motion from video and notify it via RESTful services to a UI indicating the corresponding areas on a map.

Learning Representative Vessel Trajectories Using Behavioral Cloning

Published in Proceedings of the MARESEC workshop, 2022

I was asked if I wanted to supervise a Master student interested in applications of reinforcement learning. Why not? I was eager to learn! Fortunately, he was very motivated and ended up doing a nice work for predicting vessels trajectories.

Learning Representative Trajectories of Dynamical Systems via Domain-Adaptive Imitation

Published in arXiv, 2023

Transferring style in unsupervised image-to-image translation was first cleverly done using cycle-consistent GANs. I noticed that similar generative modeling ideas could be used to let an artificial agent learn trajectories (geometry + evolution) by imitation.

Look ATME: The Discriminator Mean Entropy Needs Attention

Published in Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, 2023

Ideas from non-equilibrium thermodynamics coming back! In the GAN game for supervised image-to-image translation, the generator and discriminator don’t share information symmetrically, usually hindering equilibration … Maxwell’s demon?

teaching

Teaching experience 1

Undergraduate course, University 1, Department, 2014

This is a description of a teaching experience. You can use markdown like any other post.

Teaching experience 2

Workshop, University 1, Department, 2015