The system is modeled as a single-server queueing system having a finite number of each of two types of worker: document user and document entry operator. Worker think times are assumed to be exponentially distributed while job service times are drawn from general distributions; worker think times and job service times are dependent upon worker type. Throughput and waiting times as a function of the number of users of each type are analyzed under a nonpreemptive rule in which document use has priority over document entry.>

The authors consider worker waiting times and throughput for an optical-disk-based document storage and retrieval system in an office environment. They model the system as a single-server queuing system having a finite number of each of two types of worker: document user and document entry. Worker think times are assumed to be exponentially distributed while job service times are drawn from general distributions; worker think times and job service times are dependent on worker type. Throughput and waiting time as a function of the number of users of each type are analyzed under a nonpreemptive rule in which document use has priority over document entry. The methodology developed to assess average delays in finite-source queuing systems with priority appears to be novel.>

In a packet voice communication system, packets are fed to a common queue by a number of independent voice sources and are removed from this queue on a first-come-first-serve basis for transmission over a communication link of finite capacity. Each voice source alternates between active periods, during which packets are generated at regular intervals, and inactive periods, during which no packets are generated. In this paper, we discuss three models, a semi-Markov process model, a continuous-time Markov chain model, and a uniform arrival and service model, to assess the queueing behavior of such systems. Numerical results obtained from each of the three models are compared to each other, to results obtained from a discrete event simulation program, and to results obtained from anM/D/1analysis. Parameters of the model are the average duration of active and inactive periods, the packet generation rate, the communication link capacity, and the total number of voice sources. Conclusions are drawn regarding which models appear to be most appropriate in the parameter ranges investigated.