Kharazmi University International Journal of Supply and Operations Management 2383-1359 1 1 2014 05 01 Analysis of an M/G/1 Queue with Multiple Vacations, N-policy, Unreliable Service Station and Repair Facility Failures 1 19 1900 10.22034/2014.1.01 EN Wenqing Wu School of Mathematics & Software Science, Sichuan Normal University, Chengdu, Sichuan, 610068, China Yinghui Tang School of Mathematics & Software Science, Sichuan Normal University, Chengdu, Sichuan, 610068, China Miaomiao Yu School of Science, Sichuan University of Science and Engineering, Zigong, Sichuan, 643000, China Journal Article 2014 07 16 This paper studies an M/G/1 repairable queueing system with multiple vacations and N-policy, in which the service station is subject to occasional random breakdowns. When the service station breaks down, it is repaired by a repair facility. Moreover, the repair facility may fail during the repair period of the service station. The failed repair facility resumes repair after completion of its replacement. Under these assumptions, applying a simple method, the probability that the service station is broken, the rate of occurrence of breakdowns of the service station, the probability that the repair facility is being replaced and the rate of occurrence of failures of the repair facility along with other performance measures are obtained. Following the construction of the long-run expected cost function per unit time, the direct search method is implemented for determining the optimum threshold N* that minimises the cost function. http://www.ijsom.com/article_1900_9fdb62f932adf55af2c0e09e55861964.pdf