We revisit classical sieves for computing primes and analyze their performance in the external-memory model. Most prior sieves are analyzed in the RAM model, where the focus is on minimizing both the total number of operations and the size of the working set. The hope is that if the working set fits in RAM, then the sieve will have good I/O performance, though such an outcome is by no means gua...

one of the most important issues in the plant layout design especially in mass production organizations with high inter-plant logistics is‘material flow and inter-plant traffic analysis and its effects on the production capabilities or pauses in production lines. in this paper the inter-plant traffic analysis issue on the basis of single channel queue model (m/m/1) is analyzed in a carmaker c...

We consider a one dimensional stochastic control problem that arises from queueing network applications. The state process corresponding to the queue-length is given by a stochastic differential equation which reflects at the origin. The controller can choose the drift coefficient which represents the service rate and the buffer size b > 0. When the queue-length reaches b, the new customers are...

To better understand how to interpret birth-and-death (BD) processes fit to service system data, we investigate the consequences of fitting a BD process to a multi-server queue with a periodic time-varying arrival rate function. We study how this fitted BD process is related to the original queue-length process. If a BD process is fit to a segment of the sample path of the queue-length process,...

Queueing delays experienced by packets buffered at a node are among the most difficult to predict when considering the performance of a flow in a network. The arrivals of packets at a node tend to be highly variable so that a finite-buffer single-server queue with general arrivals and service emerges as a natural model of a network link. In this paper we propose an approach to the solution of s...

Evolutionary optimization is often applied to problems, where simulations or experiments used as the fitness function are expensive to run. In such cases, surrogate models are used to reduce the number of fitness evaluations. Some of the problems also require a fixed size batch of solutions to be evaluated at a time. Traditional methods of selecting individuals for true evaluation to improve th...

Nodal congestion in ABR traac control design is often detected by comparison of present queue size with a pre-assigned queue-threshold. Such queue-threshold detection has the disadvantage of delayed congestion detection and undesired extension of congestion periods. In consequence, the oscillation of ABR traac in each control feedback loop is unnecessarily extended and magniied, causing a large...

We use a discrete-time dynamical feedback system model of TCP/RED to study the performance of Random Early Detection RED for different values of control parameters. Our analysis shows that the queue length is able to keep stable at a given target if the maximum probability pmax and exponential averaging weight w satisfy some conditions. From the mathematical analysis, a new self-tuning RED is p...

AblJract Two queues are fed by independent, time-homogeneous Poisson arrival processes. One server is available to handle both. All service-durations, in both queues, are 'drawn independently from the sarpe distril?uUon. A ~etup time is. incurred whenever the server moves (switches) from one queue to the other. We prove that in order to minimize the sum of discounted setup charges and holding c...