As stated in Resistance (2016), the term "center of gravity" is a phrase taken from the works of Prussian (Germany) General Carl Von Clausewitz, and it refers to " a source of strength and it could be communications, transportation, or munitions."
High Frequency (HF) radio is used for first-line and backup communications over long distances, mainly in remote regions of the developed world and in developing countries. HF radio will never replace fixed (landline) and mobile telephony as the first communications option for the general public, but for organizations involved in emergency, remote and military communications it is a vital and irreplaceable wireless communications tool.
"Fog of War" refers to the uncertainty with respect to the loss of blood and fortune when conducting such battles.
DIA is short for Defense Intelligence Agency.
LOP is short for Line of Position.