Mathematical model with allowance of repeated calls for the support centers

This work presents mathematical model for call center. It was developed for estimation of probabilistic-temporal parameters influence on call center effectiveness. We derived formulas for determination of mean time for call at the input during primary and repeated call receipt, and formulas for evaluation of control traffic overhead value by primary and repeated calls for the first and second level operators. Derived formulas take into account mean time of post-processing calls. The paper represents plot of call loss probability dependence on service failure intensity due to customer impatience, unacceptable waiting time and repeated calls.