1 Decoherence-free subspaces, subspace of a system's Hilbert space where the system is decoupled from the environment.  Dynamic Frequency Selection, part of the IEEE 802.11h wireless standard.
The American Psychological Association (APA) is a scientific and professional organization that represents psychologists in the United States.
The Army Engineer Association (AEA) is a member-based, non-profit corporation specifically organized to facilitate cohesion, interaction, and networking within the United States Army Corps of Engineers total family of soldiers, civilians, family members, and alumni.