Computational Resiliency: Reliable Heterogeneous Applications

This thesis presents the notion of computational resiliency to provide reliability in heterogeneous distributed applications. The notion provides both software fault tolerance and the ability to tolerate information warfare (IW) attacks. This technology seeks to strengthen a military mission, rather than protect its network infrastructure using static defense measures such as network security, intrusion sensors, and firewalls. Even if a failure or successful attack is never detected, it should be possible to continue information operations and achieve mission objectives. Computational resiliency involves the dynamic use of replicated software structures, guided by mission policy, to achieve reliable operation. However, it goes further to automatically regenerate replication in response to a failure or attack, allowing the level of system reliability to be restored and maintained. Replicated structures can be protected through several techniques such as camouflage, dispersion, and layered security policy. This thesis examines a prototype concurrent programming technology to support computational resiliency in a heterogeneous distributed computing environment. The performance of the technology is explored through two example applications, concurrent sonar processing and remote sensing. We develop the associated performance analytical model and verify the model against the experimental results. Overhead of computational resiliency over homogeneous and heterogeneous systems are investigated. Load balancing techniques are used to improve the overall performance of the system especially on heterogeneous computing environments.