2 code implementations • 23 Jan 2024 • Liqun Zhao, Keyan Miao, Konstantinos Gatsis, Antonis Papachristodoulou
Reinforcement learning (RL) excels in applications such as video games and robotics, but ensuring safety and stability remains challenging when using RL to control real-world systems where using model-free algorithms suffering from low sample efficiency might be prohibitive.
no code implementations • 6 Nov 2023 • Xiao Tan, Antonis Papachristodoulou, Dimos V. Dimarogonas
This paper proposes a (control) barrier function synthesis and safety verification scheme for interconnected nonlinear systems based on assume-guarantee contracts (AGC) and sum-of-squares (SOS) techniques.
no code implementations • 12 Jul 2023 • Matthew Newton, Antonis Papachristodoulou
However, one prominent issue with these methods is that they use existing neural network architectures tailored for traditional machine learning tasks.
1 code implementation • 8 Apr 2023 • Liqun Zhao, Konstantinos Gatsis, Antonis Papachristodoulou
Reinforcement learning (RL) has demonstrated impressive performance in various areas such as video games and robotics.
no code implementations • 22 Mar 2023 • Han Wang, Antonis Papachristodoulou, Kostas Margellos
Both the scenario sampling and safety verification procedures are fully distributed.
no code implementations • 28 Apr 2022 • Xuda Ding, Han Wang, Jianping He, Cailian Chen, Kostas Margellos, Antonis Papachristodoulou
Simulations demonstrates that BRSCA has a higher probability of finding feasible solutions, reduces the computation time by about 17. 4% and the energy cost by about four times compared to other methods in the literature.
no code implementations • 8 Apr 2022 • Matthew Newton, Antonis Papachristodoulou
These higher order Lyapunov functions are used in conjunction with higher order multipliers on the inequality and equality constraints that bound the neural network input-output properties.
no code implementations • 4 Feb 2022 • Matthew Newton, Antonis Papachristodoulou
Depending on the complexity of these bounds, the computational time of the optimisation problem varies, with longer solve times often leading to tighter bounds.
2 code implementations • 14 Jul 2018 • Yang Zheng, Giovanni Fantuzzi, Antonis Papachristodoulou
Optimization over non-negative polynomials is fundamental for nonlinear systems analysis and control.
Optimization and Control Systems and Control
2 code implementations • 8 Apr 2018 • Yang Zheng, Giovanni Fantuzzi, Antonis Papachristodoulou
We show that a subset of sparse SOS matrices with chordal sparsity patterns can be equivalently decomposed into a sum of multiple SOS matrices that are nonzero only on a principal submatrix.
Optimization and Control Systems and Control
2 code implementations • 17 Jul 2017 • Yang Zheng, Giovanni Fantuzzi, Antonis Papachristodoulou, Paul Goulart, Andrew Wynn
We employ chordal decomposition to reformulate a large and sparse semidefinite program (SDP), either in primal or dual standard form, into an equivalent SDP with smaller positive semidefinite (PSD) constraints.
Optimization and Control
2 code implementations • 6 Nov 2016 • Yang Zheng, Giovanni Fantuzzi, Antonis Papachristodoulou, Paul Goulart, Andrew Wynn
We propose an efficient first-order method, based on the alternating direction method of multipliers (ADMM), to solve the homogeneous self-dual embedding problem for a primal-dual pair of semidefinite programs (SDPs) with chordal sparsity.
Optimization and Control
2 code implementations • 20 Sep 2016 • Yang Zheng, Giovanni Fantuzzi, Antonis Papachristodoulou, Paul Goulart, Andrew Wynn
We show that chordal decomposition can be applied to either the primal or the dual standard form of a sparse SDP, resulting in scaled versions of ADMM algorithms with the same computational cost.
Optimization and Control
no code implementations • 18 Nov 2013 • Jan-Peter Calliess, Antonis Papachristodoulou, Stephen J. Roberts
In contrast to previous work that has used stochastic processes for identification, we leverage the structural knowledge afforded by Lagrangian mechanics and learn the drift and control input matrix functions of the control-affine system separately.
3 code implementations • 17 Oct 2013 • Antonis Papachristodoulou, James Anderson, Giorgio Valmorbida, Stephen Prajna, Pete Seiler, Pablo Parrilo
Specifically, polynomial and SOS variable declarations made using sossosvar, sospolyvar, sosmatrixvar, etc now return a new polynomial structure, dpvar.
Optimization and Control Mathematical Software Systems and Control