Search Results for author: Iman Shames

Found 19 papers, 3 papers with code

Regret Analysis of Online LQR Control via Trajectory Prediction and Tracking: Extended Version

no code implementations21 Feb 2023 Yitian Chen, Timothy L. Molloy, Tyler Summers, Iman Shames

We adopted the notion of dynamic regret to measure the performance of this proposed online LQR control method, with our main result being that the (dynamic) regret of our method is upper bounded by a constant.

Trajectory Prediction

Minimum-Time Escape from a Circular Region for a Dubins Car

no code implementations3 Nov 2022 Timothy L. Molloy, Iman Shames

We investigate the problem of finding paths that enable a robot modeled as a Dubins car (i. e., a constant-speed finite-turn-rate unicycle) to escape from a circular region of space in minimum time.

The Replicator Dynamic, Chain Components and the Response Graph

no code implementations30 Sep 2022 Oliver Biggar, Iman Shames

We settle an open problem establishing that under the replicator, sink chain components -- a topological notion of long-run outcome of a dynamical system -- always exist and are approximated by the sink connected components of the game's response graph.

Robust Data-Driven Output Feedback Control via Bootstrapped Multiplicative Noise

no code implementations10 May 2022 Benjamin Gravell, Iman Shames, Tyler Summers

We propose a robust data-driven output feedback control algorithm that explicitly incorporates inherent finite-sample model estimate uncertainties into the control design.

Risk-Bounded Temporal Logic Control of Continuous-Time Stochastic Systems

no code implementations8 Apr 2022 Sleiman Safaoui, Lars Lindemann, Iman Shames, Tyler H. Summers

Our control approach relies on reformulating these risk predicates as deterministic predicates over mean and covariance states of the system.

Risk Bounded Nonlinear Robot Motion Planning With Integrated Perception & Control

1 code implementation5 Jan 2022 Venkatraman Renganathan, Sleiman Safaoui, Aadi Kothari, Benjamin Gravell, Iman Shames, Tyler Summers

Robust autonomy stacks require tight integration of perception, motion planning, and control layers, but these layers often inadequately incorporate inherent perception and prediction uncertainties, either ignoring them altogether or making questionable assumptions of Gaussianity.

Model Predictive Control Motion Planning

Learning Safety Filters for Unknown Discrete-Time Linear Systems

no code implementations1 Nov 2021 Farhad Farokhi, Alex S. Leong, Mohammad Zamani, Iman Shames

A learning-based safety filter is developed for discrete-time linear time-invariant systems with unknown models subject to Gaussian noises with unknown covariance.

Toward nonlinear dynamic control over encrypted data for infinite time horizon

no code implementations12 Oct 2021 Junsoo Kim, Farhad Farokhi, Iman Shames, Hyungbo Shim

In this note, we demonstrate that it is possible to run a dynamic controller over encrypted data for an infinite time horizon if the output of the controller can be represented as a function of a fixed number of previous inputs and outputs.

Quantization

Temporal Logic Planning for Minimum-Time Positioning of Multiple Threat-Seduction Decoys

no code implementations17 Jun 2021 Tony A. Wood, Mitchell Khoo, Elad Michael, Chris Manzie, Iman Shames

The task of a decoy reaching a state in which the lock of the assigned threat can be broken is formulated as a temporal logic specification.

Collision Avoidance Motion Planning +1

Fast Spline Trajectory Planning: Minimum Snap and Beyond

no code implementations4 May 2021 Declan Burke, Airlie Chapman, Iman Shames

In this paper, we study spline trajectory generation via the solution of two optimisation problems: (i) a quadratic program (QP) with linear equality constraints and (ii) a nonlinear and nonconvex optimisation program.

Trajectory Planning

An expressiveness hierarchy of Behavior Trees and related architectures

no code implementations16 Apr 2021 Oliver Biggar, Mohammad Zamani, Iman Shames

In this paper we provide a formal framework for comparing the expressive power of Behavior Trees (BTs) to other action selection architectures.

Safe Learning of Uncertain Environments

no code implementations2 Mar 2021 Farhad Farokhi, Alex Leong, Iman Shames, Mohammad Zamani

We show that with an arbitrarily large probability we can guarantee that the state will remain in the safe set, while learning and control are carried out simultaneously, provided that a feasible solution exists for the optimization problem.

Approximate Midpoint Policy Iteration for Linear Quadratic Control

1 code implementation28 Nov 2020 Benjamin Gravell, Iman Shames, Tyler Summers

We present a midpoint policy iteration algorithm to solve linear quadratic optimal control problems in both model-based and model-free settings.

On modularity in reactive control architectures, with an application to formal verification

no code implementations28 Aug 2020 Oliver Biggar, Mohammad Zamani, Iman Shames

We use a Linear Temporal Logic-based verification scheme to verify the correctness of this structure, and then show how one can modify modules while preserving its correctness.

A principled analysis of Behavior Trees and their generalisations

no code implementations27 Aug 2020 Oliver Biggar, Mohammad Zamani, Iman Shames

As complex autonomous robotic systems become more widespread, the need for transparent and reusable Artificial Intelligence (AI) designs becomes more apparent.

Decision Making

Online Stochastic Convex Optimization: Wasserstein Distance Variation

no code implementations2 Jun 2020 Iman Shames, Farhad Farokhi

Distributionally-robust optimization is often studied for a fixed set of distributions rather than time-varying distributions that can drift significantly over time (which is, for instance, the case in finance and sociology due to underlying expansion of economy and evolution of demographics).

Sociology Stochastic Optimization

Ordinal Optimisation for the Gaussian Copula Model

1 code implementation5 Nov 2019 Robert Chin, Jonathan E. Rowe, Iman Shames, Chris Manzie, Dragan Nešić

We present results on the estimation and evaluation of success probabilities for ordinal optimisation over uncountable sets (such as subsets of $\mathbb{R}^{d}$).

Optimization and Control Probability

Predictive Online Convex Optimization

no code implementations15 May 2019 Antoine Lesage-Landry, Iman Shames, Joshua A. Taylor

We show that under these conditions and without any assumptions on the predictability of the environment, the predictive update strictly improves on the performance of the standard update.

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