Abstract: Waiting lines and service systems are important parts of the business world. In this article we describe several common queuing situations and present mathematical models for analyzing waiting lines following certain assumptions. Those assumptions are that (1) arrivals come from an infinite or very large population, (2) arrivals are Poisson distributed, (3) arrivals are treated on a FIFO basis and do not balk or renege, (4) service times follow the negative exponential distribution or are constant, and (5) the average service rate is faster than the average arrival rate.
The model illustrated in this Bank for customers on a level with service is the multiple-channel queuing model with Poisson Arrival and Exponential Service Times (M/M/S). After a series of operating characteristics are computed, total expected costs are studied, total costs is the sum of the cost of providing service plus the cost of waiting time. Finally we find the total minimum expected cost.
Keywords: Service; FIFO; M/M/s; Poisson distribution; Queue; Service cost; Utilization factor; Waiting cost; Waiting time, optimization.
History: Queuing theory had its beginning in the research work of a Danish engineer named A.K. Erlang. In 1909 Erland experimented with fluctuating demand in telephone traffic. Eight years letter he published a report addressing the delays in automatic dialling equipment. At the end of World War II, Erlang’s early work was extended to more general problems and to business applications of waiting lines.