Biblio

Improvements in mobile networking combined with the ubiquitous availability and adoption of low-cost development boards have enabled the vision of mobile platforms of Cyber-Physical Systems (CPS), such as fractionated spacecraft and UAV swarms. Computation and communication resources, sensors, and actuators that are shared among different applications characterize these systems. The cyber-physical nature of these systems means that physical environments can affect both the resource availability and software applications that depend on resource availability. While many application development and management challenges associated with such systems have been described in existing literature, resilient operation and execution have received less attention. This paper describes our work on improving runtime support for resilience in mobile CPS, with a special focus on our runtime infrastructure that provides autonomous resilience via self-reconfiguration. We also describe the interplay between this runtime infrastructure and our design-time tools, as the later is used to statically determine the resilience properties of the former. Finally, we present a use case study to demonstrate and evaluate our design-time resilience analysis and runtime self-reconfiguration infrastructure.

Multi-module Cyber-Physical Systems (CPSs), such as satellite clusters, swarms of Unmanned Aerial Vehicles (UAV), and fleets of Unmanned Underwater Vehicles (UUV) are examples of managed distributed real-time systems where mission-critical applications, such as sensor fusion or coordinated flight control, are hosted. These systems are dynamic and reconfigurable, and provide a “CPS cluster-as-a-service” for mission-specific scientific applications that can benefit from the elasticity of the cluster membership and heterogeneity of the cluster members. Distributed and remote nature of these systems often necessitates the use of Deployment and Configuration (D&C) services to manage lifecycle of software applications. Fluctuating resources, volatile cluster membership and changing environmental conditions require resilience. However, due to the dynamic nature of the system, human intervention is often infeasible. This necessitates a self-adaptive D&C infrastructure that supports autonomous resilience. Such an infrastructure must have the ability to adapt existing applications on the fly in order to provide application resilience and must itself be able to adapt to account for changes in the system as well as tolerate failures.

This paper describes the design and architectural considerations to realize a self-adaptive, D&C infrastructure for CPSs. Previous efforts in this area have resulted in D&C infrastructures that support application adaptation via dynamic re-deployment and re-configuration mechanisms. Our work, presented in this paper, improves upon these past efforts by implementing a self- adaptive D&C infrastructure which itself is resilient. The paper concludes with experimental results that demonstrate the autonomous resilience capabilities of our new D&C infrastructure.