Inflation rate is defined as the rate at which the cost general level of goods and services increases resulting in decreases of purchasing power of goods and services.

A system is a group of interacting or interrelated elements that act according to a set of rules to form a unified whole. 
An 'information system' means a discrete set of information resources organized for the collection, processing, maintenance, use, sharing, dissemination, or disposition of information.

Engineering economics, previously known as engineering economy, is a subset of economics concerned with the use and "...application of economic principles" in the analysis of engineering decisions.