I am currently doing an internship at Motional in Singapore. Starting October, I will be a PhD student in Prof. Marta Kwiatkowska's group at the University of Oxford. My interests lie in safe and reliable machine learning and autonomous systems, applied mathematics, and compositional theories.

Before joining Motional I got my MSc at ETH Zürich focusing on robotics, machine learning, statistics, and applied category theory. My thesis was on Compositional Computational Systems. At ETH, I was working closely with Prof. Emilio Frazzoli's group and my studies were generously funded by the Excellence Scholarship & Opportunity Programme (ESOP).

Before that, I received my BSc in Aerospace Engineering from TU Delft and did my final project under the supervision of Christophe de Wagter of the Micro Air Vehicle Laboratory. I also had the pleasure to work with Ron Noomen on spacecraft trajectory optimization.



Updates

June 2021
Starting October, I will be joining Prof. Marta Kwiatkowska's group at the University of Oxford as a PhD student working on formal verification for machine learning. I will be part of the EPSRC Centre for Doctoral Training in Autonomous Intelligent Machines and Systems and will be funded by Toyota!
May 2021
I am happy to share that I am starting an internship at Motional in Singapore! I will be working on detecting the safe operational envelope of the Motional self-driving stack.
October 2020
I presented the final results of my Master Thesis! The title is Compositional Computational Systems and it deals with the problem of problem-solving. You can find the presentation and the thesis itself under Publications.
July 2020
Our paper, Integrated Benchmarking and Design for Reproducible and Accessible Evaluation of Robotic Agents, a collaboration between ETH Zürich, Université de Montréal, and Toyota Technological Institute at Chicago, got accepted at IROS2020.
March 2020
I started my Master thesis under the supervision of Gioele Zardini and Dr. Andrea Censi in Prof. Emilio Frazzoli's group, at the Institute for Dynamic Systems and Control, ETH Zürich. We are working on a Compositional Computational Theory in the context of Applied Category Theory.
February 2020
I concluded my semester project with Daedalean under the supervision of Prof. Thomas Hofmann. We worked on machine learning models which utilize additional inputs at training time, showed how they can be formulated as an optimization problem over mutual information terms, and explored their implications to model certification.
January 2020
Our paper, Learning Camera Miscalibration Detection on which I worked at the Autonomous Systems Lab got accepted at ICRA2020.

Publications


Compositional Computational Systems

Aleksandar Petrov, supervised by Gioele Zardini, Andrea Censi, Emilio Frazzoli

Master thesis

[Abstract] [Thesis] [Slides] [Presentation]

We propose a collection of formal definitions for problems and solutions, and study the relationships between the two. Problems and solutions can be represented as morphisms in two categories, and the structure of problem reduction and problem-solving has the properties of a heteromorphic twisted arrow category (a generalization of the twisted arrow category) defined on them. Lagado, a compositional computational system built on a type-theoretic foundation that accounts for the resources required for computation is provided as an example.
This thesis furthermore provides the universal conditions for defining any compositional computational system. We argue that any problem can be represented as a function from the product of hom-sets of two semicategories to a rig (a kinded function) and that any procedure can also be represented as a similar kinded function. Combining all problems and procedures defined over the same subcategory of SemiCat via a solution judgment map results in a heteromorphic twisted arrow category called Laputa, which automatically provides problem-reducing and problem-solving properties.
The thesis illustrates the practical application of the theory of compositional computations systems by studying the representation of co-design problems from the theory of mathematical co-design as part of several different compositional computations systems. In the process, new results on the conditions for the solvability of co-design problems and their compositional category-theoretical properties are also presented.


Integrated Benchmarking and Design for Reproducible and Accessible Evaluation of Robotic Agents

Jacopo Tani, Andrea F. Daniele, Gianmarco Bernasconi, Amaury Camus, Aleksandar Petrov, Anthony Courchesne, Bhairav Mehta, Rohit Suri, Tomasz Zaluska, Matthew R. Walter, Emilio Frazzoli, Liam Paull, Andrea Censi

IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS) 2020

[Abstract] [arXiv]

As robotics matures and increases in complexity, it is more necessary than ever for robot autonomy research to be “reproducible”. Compared to other sciences, there are specific challenges to benchmarking autonomy, such as the complexity of the software stacks, the variability of the hardware and the reliance on data-driven techniques, amongst others. In this paper we describe a new concept for reproducible research, in which development and benchmarking are integrated, so that reproducibility is obtained “by design” from the beginning of the research/development processes. We provide the overall conceptual objectives to achieve this goal and then provide a concrete instance that we have built, the DUCKIENet. One of the central components of this setup is the Duckietown Autolab, a remotely accessible standardized setup that is itself also relatively low cost and reproducible. When evaluating agents, careful definition of interfaces allows users to choose among local vs. remote evaluation using simulation, logs, or the remote automated hardware setups. We validate the system by analyzing the repeatability of experiments run using the infrastructure and show that there is low variance across different robot hardware and across different remote labs.

Learning Camera Miscalibration Detection

Andrei Cramariuc*, Aleksandar Petrov*, Rohit Suri, Mayank Mittal, Roland Siegwart, Cesar Cadena

IEEE International Conference on Robotics and Automation (ICRA) 2020

[Abstract] [arXiv] [Code]

Self-diagnosis and self-repair are some of the key challenges in deploying robotic platforms for long-term real-world applications. One of the issues that can occur to a robot is miscalibration of its sensors due to aging, environmental transients, or external disturbances. Precise calibration lies at the core of a variety of applications, due to the need to accurately perceive the world. However, while a lot of work has focused on calibrating the sensors, not much has been done towards identifying when a sensor needs to be recalibrated. This paper focuses on a data-driven approach to learn the detection of miscalibration in vision sensors, specifically RGB cameras. Our contributions include a proposed miscalibration metric for RGB cameras and a novel semi-synthetic dataset generation pipeline based on this metric. Additionally, by training a deep convolutional neural network, we demonstrate the effectiveness of our pipeline to identify whether a recalibration of the camera's intrinsic parameters is required or not.

Optimizing multi-rendezvous spacecraft trajectories: ΔV matrices and sequence selection

Aleksandar Petrov, Ron Noomen

[Abstract] [arXiv]

Multi-rendezvous spacecraft trajectory optimization problems are notoriously difficult to solve. For this reason, the design space is usually pruned by using heuristics and past experience. As an alternative, the current research explores some properties of ΔV matrices which provide the minimum ΔV values for a transfer between two celestial bodies for various times of departure and transfer duration values. These can assist in solving multi-rendezvous problems in an automated way. The paper focuses on the problem of, given a set of candidate objects, how to find the sequence of N objects to rendezvous with that minimizes the total ΔV required. Transfers are considered as single algebraic objects corresponding to ΔV matrices, which allow intuitive concatenation via a generalized summation. Waiting times, both due to mission requirements and prospects for cheaper and faster future transfers, are also incorporated in the ΔV matrices. A transcription of the problem as a shortest path search on a graph can utilize a range of available efficient shortest path solvers. Given an efficient ΔV matrix estimator, the new paradigm proposed here is believed to offer an alternative to the pruning techniques currently used.