Reliability and Vacation: The Critical Issue

Abstract

Predicting and understanding the machining system performance is a constant challenge in the process industries like manufacturing and production systems, computer and communication systems, just-in-time (JIT) service systems. The reliability modeling supports the decision-making process from early to the optimal state-of-the-art design of the machining system. Reliability measures account the performance of different preventive, predictive, corrective, zero-hours, and periodic maintenance strategies. For all strategies, the most anterior arrangement is the availability of the service facility as and when required to maintain the high grade or efficient quality of service (QoS). The permanent service facility may increase cost, idleness, deterioration in quality. To reduce the wastage of valuable resources like time, money, quality, etc., vacation is a prominent idea for the service facility. The vacation time is a period of time of not doing the usual service or activities. In this time, the server may take rest to rejuvenate, to reduce idle time at the station, to diminish the expected cost incurred in service. The long vacation time also wastes the valuable resources substantially due to the long waiting queue of failed machines. The vacation time period is a critical issue and needs to analyze judgementally. In this chapter, a comparative study of different vacation policies on the reliability characteristics of the machining system is presented. For that purpose, the queueing-theoretic approach is employed, and the Markovian models are developed for various types of vacation policy namely N-policy, single vacation, multiple vacations, Bernoulli vacation, working vacation, vacation interruption, etc. For all vacation policies, the reliability and mean-time-to-failure (MTTF) of the system are compared, and results are depicted in the graphs for quick insights. From this study, readers get a glance to understand about vacation, researchers get a concrete platform to choose appropriate assumptions for their research in machining/service system or system analyst may opt suitable vacation policy as per limitation of the system.