Depth-first search. Depth-first search (DFS) is an algorithm for traversing or searching tree or graph data structures. One starts at the root (selecting some arbitrary node as the root in the case of a graph) and explores as far as possible along each branch before backtracking.
Derivative classification is: the incorporating, paraphrasing, restating, or generating in new form information that is already classified and the marking of the new material consistent with the classification of the source material, or the marking of the information in accordance with an authorized classification guide.
Energy derivative. An energy derivative is a derivative contract based on (derived from) an underlying energy asset, such as natural gas, crude oil, or electricity. Energy derivatives are exotic derivatives and include exchange-traded contracts such as futures and options, and over-the-counter (i.e., privately negotiated) derivatives such as forwards, swaps and options. Major players in the energy derivative markets include major trading houses, oil companies, utilities, and financial institutions.