Glossary ยท approach
Queueing Theory
Mathematical discipline analyzing waiting lines where arrivals and service times are random.
Waiting Line TheoryQueue Theory
Queueing theory studies waiting times, queue lengths, and system utilization when customers arrive at random and service times are stochastic. Founded by Agner Krarup Erlang in 1909 at the Copenhagen Telephone Company to compute switch capacity. Models follow Kendall's notation A/B/c โ A is the arrival process (M = Markov/Poisson, G = general), B the service process, c the number of parallel servers. Classical examples: M/M/1, M/M/c, M/G/1. Little's Law (L = ฮปW) applies to all steady-state queues: mean customers in system = arrival rate ร mean time in system. Applications: call centers (Erlang-C/A), hospital emergency rooms, production lines, logistics terminals, computer network traffic, bank teller systems.
รrnek
A 150-seat call center with 600 calls/hour and 4-minute AHT in the 09:00-10:00 interval needs 47 agents to meet an 80/20 service-level target โ queueing theory delivers that number.