ABSTRACT
Important foundations for using nondeterministic models are the notions of random process and uncertainty. The top-down approach, which relies on what is known or perceived to be objectives of the systems coupled with a process of logical elimination or exclusion, provides general set of risks. The elements of a queuing system are identified, various performance parameters of queuing systems are described, and how to model common and specialized engineering problems as queuing systems are explained. Systems engineer, similar to a weather forecaster, often needs to describe a phenomenon with the objective of helping himself or someone else arrive at a decision. The notions of necessary and sufficient causes taken together form the foundation of judging causality in many fields including systems engineering and risk analysis. From a systems analysis perspective, the two commonly held approaches to the identification of risk scenarios are bottom-up and top-down approaches.
