Network, System, and IT Security Engineering
(Computer Science)

Architects and engineers are among the most fortunate of men since they build their own monuments with public consent, public approval and often public money.

Engineering: The art of organizing and directing men, and of controlling the forces and materials of nature for the benefit of the human race.

In terms of the quantum theory, a system is defined as a collection of bands corresponding to a common transition between two major electron levels. Sets of bands in a system can be selected such that the frequency intervals between successive bands in the set change in an arithmetic progression. These sets can be chosen in two different ways, the frequency intervals increasing in opposite directions in the two sets. Deslandres, who did the pioneer work in this field, called one series of such sets " first progressions," and the other series " second progressions." An entire system of bands, often eighty or more in number, can thus be represented as a function of two parameters p and n. The parameter n varies in a first progression, p remaining constant. The parameter p varies in a second progression, n remaining constant.