1 code implementation • 28 Feb 2024 • Hongchao Zhang, Luyao Niu, Andrew Clark, Radha Poovendran
Control barrier function (CBF)-based approaches have been proposed to guarantee the safety of robotic systems.
1 code implementation • NeurIPS 2023 • Junlin Wu, Andrew Clark, Yiannis Kantaros, Yevgeniy Vorobeychik
However, finding Lyapunov functions for general nonlinear systems is a challenging task.
no code implementations • 28 Apr 2023 • Andrew Clark, Stuart Phinn, Peter Scarth
Our results showed: a stratified random sampling approach for producing training patches improved the accuracy of classes with a smaller area while having minimal effect on larger classes; a smaller number of larger patches compared to a larger number of smaller patches improves model accuracy; applying data augmentations and scaling are imperative in creating a generalised model able to accurately classify LULC features in imagery from a different date and sensor; and producing the output classification by averaging multiple grids of patches and three rotated versions of each patch produced and more accurate and aesthetic result.
no code implementations • 4 Apr 2023 • Abdullah Al Maruf, Luyao Niu, Bhaskar Ramasubramanian, Andrew Clark, Radha Poovendran
We then propose a distributed MARL algorithm called the CVaR QD-Learning algorithm, and establish that value functions of individual agents reaches consensus.
no code implementations • 14 Feb 2023 • Hongchao Zhang, Zhouchi Li, Shiyu Cheng, Andrew Clark
In this paper, we propose an approach to detect and mitigate LiDAR spoofing attacks by leveraging LiDAR scan data from other neighboring vehicles.
no code implementations • 31 Aug 2022 • Andrew Clark
Based on these conditions, we propose a framework for verifying safety of CBF-based control including single CBFs, high-order CBFs, multi-CBFs, and systems with trigonometric dynamics and actuation constraints.
no code implementations • 22 Aug 2022 • Luyao Niu, Zhouchi Li, Andrew Clark
We develop a class of fault-tolerant finite time convergence control barrier functions (CBFs) to guarantee that a dynamical system reaches a set within finite time almost surely in the presence of malicious attacks.
no code implementations • 11 Aug 2022 • Hongchao Zhang, Shiyu Cheng, Luyao Niu, Andrew Clark
We prove that the synthesized control input guarantees system safety using control barrier certificates.
no code implementations • 11 Jul 2022 • Hongchao Zhang, Zhouchi Li, Andrew Clark
Safety is one of the most important properties of control systems.
no code implementations • 28 Sep 2021 • Luyao Niu, Hongchao Zhang, Andrew Clark
By satisfying the constructed CBF constraint at each sampling time, we guarantee the unknown sampled-data system is safe for all time.
no code implementations • 3 Aug 2021 • Luyao Niu, Dinuka Sahabandu, Andrew Clark, Radha Poovendran
In this paper, we study the controlled islanding problem of a power system under disturbances introduced by a malicious adversary.
no code implementations • 28 Apr 2021 • Andrew Clark
Our approach is to show that safety of CBFs is equivalent to the non-existence of solutions to a family of polynomial equations, and then prove that this nonexistence is equivalent to a pair of sum-of-squares constraints via the Positivstellensatz of algebraic geometry.
no code implementations • 29 Mar 2021 • Bhaskar Ramasubramanian, Luyao Niu, Andrew Clark, Radha Poovendran
In this paper, we consider a setting where an autonomous agent has to learn behaviors in an unknown environment.
no code implementations • 28 Feb 2021 • Zhouchi Li, Luyao Niu, Andrew Clark
For each possible set of compromised sensors, we maintain a state estimator disregarding the sensors in that set, and calculate the optimal LQG control input at each time based on this estimate.
no code implementations • 19 Jan 2020 • Baicen Xiao, Qifan Lu, Bhaskar Ramasubramanian, Andrew Clark, Linda Bushnell, Radha Poovendran
The output of the feedback neural network is converted to a shaping reward that is augmented to the reward provided by the environment.
no code implementations • 20 Jul 2019 • Baicen Xiao, Bhaskar Ramasubramanian, Andrew Clark, Hannaneh Hajishirzi, Linda Bushnell, Radha Poovendran
This paper augments the reward received by a reinforcement learning agent with potential functions in order to help the agent learn (possibly stochastic) optimal policies.
no code implementations • 14 Aug 2017 • Hossein Hosseini, Baicen Xiao, Andrew Clark, Radha Poovendran
At the end, we propose introducing randomness to video analysis algorithms as a countermeasure to our attacks.
no code implementations • 27 Dec 2012 • Andrew Clark
In this paper we use group, action and orbit to understand how evolutionary solve nonconvex optimization problems.