Abstract. The paper analyzes the results of application of hyper-exponential and Erlang approximations with parameters of paradoxical and complex type for calculating the steady-state characteristics of G /G /1/m queueing systems by the fictitious phase method. The results are verified using simulation models.

Keywords: non-Markovian queueing system, hyper-exponential distribution, generalized Erlang distribution, complex and paradoxical parameters of distribution, approximation.

¹ Ivan Franko National University of Lviv, Ukraine

 yu.zhernovyi@lnu.edu.ua