ABSTRACT
A man-made system is a collection of objects that interact in accordance with a set of rules to achieve some purpose or function. The hierarchical organization of these objects into a whole-part pattern forms a product entity structure for the system. Everything in the system is in its physical product entity structure. Everything else in the universe that is not in the system product entity structure is in the system environment, as depicted in Figure 1.1. The entities in the system interact with each other and with the environment selectively through interfaces, causing the entities to be capable of accomplishing ends not possible using the entities disassociated from each other. A man-made system consists of some combination of physical elements, referred to as hardware; computer software that is an intellectual construct that operates within a hardware computer; facilities and real-estate improvements; and human beings accomplishing mental activity, decision making, and work in accordance with procedures to guide human performance.
