Out-put to input Ratio:
Increasing national productivity can raise living standards because more real income improves people’s ability to purchase goods and services, enjoy leisure, improve housing and education and contribute to social and environmental programs. Productivity growth also helps businesses to be more profitable.
Signal flow graph:
A signal-flow graph (SFG) is a special type of block diagram—and directed graph—consisting of nodes and branches. Its nodes are the variables of a set of linear algebraic relations. An SFG can only represent multiplications and additions. Multiplications are represented by the weights of the branches; additions are represented by multiple branches going into one node. A signal-flow graph has a one-to-one relationship with a system of linear equations. In addition to this, it can also be used to represent the signal flow in a physical system; i.e., it can represent relations of cause and effect.