Optimized Integral Controller Searching Prime Number Orders
  The concept of integration is generally applicable to automatic control of processes. As shown in this paper, integral controller performs efficient searches in the extensive prime sets, too. An inspiration by the simple analytic rules for PID controller tuning results in integral controller that ensures predictable work regardless of the cardinality of primes. It gives an innovative application of the feedback control which relates to a gradient method. 
Petr Klan
cs.SY