tunning.py

import numpy

def get_turn_off(alpha):
    cycle_cnt =  (numpy.log(0.4) / numpy.log(1 - alpha) )
    return (cycle_cnt * 50)/ (1000 * 60)

def get_alpha_from_cut_off(cut_off):
	alpha = 1 - numpy.exp(numpy.log(0.1) / ((float(cut_off) * 60 * 1000) / float(50)))
	return alpha

cut_off = 10
alpha = get_alpha_from_cut_off(cut_off)
print get_turn_off(alpha)