there are some problems with estimating the time required for the manufacturing process of products, especially when there is a variable serving time, like control stage. these problems will cause overestimation of process time. layout constraints, reworking constraints and inflexible product schedule in multi product lines need a precise planning to reduce volume in particular situation of lin...

In this paper we consider a queuing system in which the service times of customers are independent and identically distributed random variables, the arrival process is stationary and has the property of orderliness, and the queue discipline is arbitrary. For this queuing system we obtain the steady state second moment of the queue size in terms of the stationary waiting time distribution of a s...

The major traffic in today’s internet is entirely filled with video data with increased use of Video on-Demand systems. Quality Of internet video has a great impact on user engagement. Video encoding and streaming over wireless networks become a big concern. Real time video service requires low end-to-end delay and the major concern is to reduce the queuing delay which has high impact on the vi...

We consider queuing systems as models of distance learning system we analyze how characteristics of business process in the system affect on throughput and on learning outcomes. The processes of executing tasks and tasks validation process are the key processes in the distance learning. A model of the process performed by a student is a queuing system with refusals. A model of the process perfo...

Queuing theory has extensively studied the problem of estimating job execution times in steady state conditions both in the case of single queues and queuing networks. This paper discusses the use of closed Queuing Network (QN) models during finite time intervals to estimate the execution time of jobs submitted to a computer system. More specifically, the paper presents the Epochs algorithm tha...

This paper surveys recent works on queuing approaches to a number of optimization problems in production systems, especially modem jobbing production systems (or multi-item small lot production systems) represented by flexible manufacturing systems (FMS). This paper outlines optimization problems concerning with such aspects of the system design and control as workioading, job selection, produc...

We study an admissions control problem, where a queue with service rate 1 − p receives incoming jobs at rate λ ∈ (1 − p,1), and the decision maker is allowed to redirect away jobs up to a rate of p, with the objective of minimizing the time-average queue length. We show that the amount of information about the future has a significant impact on system performance, in the heavy-traffic regime. W...

This paper presents a general energy management system for High Performance Computing (HPC) clusters and cloud infrastructures that powers off cluster nodes when they are not being used, and conversely powers them on when they are needed. This system can be integrated with different HPC cluster middleware, such as Batch-Queuing Systems or Cloud Management Systems, and can also use different mec...