Karlsruhe Accurate Arithmetic (KAA) or Karlsruhe Accurate Arithmetic Approach (KAAA), augments conventional floating-point arithmetics with good error behaviour with new operations to calculate scalar products with a single rounding error.
The foundations for KAA were developed at the University of Karlsruhe starting in the late 1960s.
References
Karlsruhe Accurate Arithmetic Wikipedia(Text) CC BY-SA