The certainty of uncertainty in real-time systems

Identifying and managing uncertainty is an essential part of the engineering of complex systems. But when dealing with real-time systems, special forms of uncertainty provide even greater challenges. Why should this be? The short answer is that real-time systems must add the assurance of temporal correctness to the already difficult task of sensor interface and device control. But the problem is really more complicated than that. In this article, the author examines the nature of uncertainty in real-time systems. While looking briefly at some traditional mathematical models of uncertainty, emphasis on this article is on the identification of uncertainty through telltale behaviors and "code smells." Then, techniques for managing, mitigating, or eliminating the uncertainty will be given.