Resilient Monotone Sequential Maximization

TL;DR

This paper introduces a scalable, resilient sequential optimization algorithm capable of handling adversarial attacks and failures, with proven approximation guarantees for monotone objectives, applicable to control and sensor scheduling tasks.

Contribution

It presents the first scalable algorithm for resilient sequential maximization that guarantees system-wide resilience and near-optimal solutions for monotone functions.

Findings

Algorithm achieves resilience against any number of failures or attacks.

Provides provable approximation guarantees based on curvature.

Validated through simulations in robot navigation scenarios.

Abstract

Applications in machine learning, optimization, and control require the sequential selection of a few system elements, such as sensors, data, or actuators, to optimize the system performance across multiple time steps. However, in failure-prone and adversarial environments, sensors get attacked, data get deleted, and actuators fail. Thence, traditional sequential design paradigms become insufficient and, in contrast, resilient sequential designs that adapt against system-wide attacks, deletions, or failures become important. In general, resilient sequential design problems are computationally hard. Also, even though they often involve objective functions that are monotone and (possibly) submodular, no scalable approximation algorithms are known for their solution. In this paper, we provide the first scalable algorithm, that achieves the following characteristics: system-wide resiliency, i.e., the algorithm is valid for any number of denial-of-service attacks, deletions, or failures; adaptiveness, i.e., at each time step, the algorithm selects system elements based on the history of inflicted attacks, deletions, or failures; and provable approximation performance, i.e., the algorithm guarantees for monotone objective functions a solution close to the optimal. We quantify the algorithm's approximation performance using a notion of curvature for monotone (not necessarily submodular) set functions. Finally, we support our theoretical analyses with simulated experiments, by considering a control-aware sensor scheduling scenario, namely, sensing-constrained robot navigation.