Two-stage multi-server tandem queue with two types of processed customers is analyzed. Priority customers always are admitted into the system. Non-priority customers are admitted into the system only if the number of busy servers at the second stage does not exceed some pre-assigned threshold. Economic criterion of the system operation is optimized with respect to the threshold.

Abstract
 1. Introduction
 2. Mathematical Model
 3. Analysis of the Model
 4. Numerical Examples
 References

• 김제숭(상지대학교 산업공학과)