Errors always occur. It is possible to reduce, and in theory eliminate, errors in a transmission or storage system. Error correction codes performs this task. These codes can also be applied to humans. The ISBN number that identifies a book has a simple error detection code which is designed to detect the most common errors and prevent an incorrect book from being delivered.
Transmission systems can use wires, fiber-optic cables, or radio waves.
A rapidly growing area is that of telecommunication networks. Some obvious characteristics of a network are that it should be fast and reliable. Of course, it should be inexpensive too. A Tomographic Algorithm for Vertical Profile Determination Using GPS Satellites, presented at the National Radio Science Meeting, Internation Union of Radio Science, Boulder CO, January 1998, S. Divakaruni and J. R. Austen. Comparison of Tomographic and Conventional Methods for Resolution of the Constant of Integration, David L. Page and Jeffrey R. Austen, Radio Science, Vol.