Performance Modeling of Critical Event Management for Ubiquitous Computing Applications

A generic theoretical framework for managing critical events in ubiquitous computing systems is presented. The main idea is to automatically respond to occurrences of critical events in the system and mitigate them in a timely manner. This is different from traditional fault-tolerance schemes, where fault management is performed only after system failures. To model the critical event management, the concept of criticality, which characterizes the effects of critical events in the system, is defined. Each criticality is associated with a timing requirement, called its window-of-opportunity, which needs to be fulfilled in taking mitigative actions to prevent system failures.