Toshihisa Ozawa

Alternating service queues with mixed exhaustive and K -limited services

Abstract A single server model with two queues is analyzed. The service discipline used in one queue is “exhaustive” and that in the other queue is “ K -limited”. For a model without walking time, represented as a piecewise Markov process, the mean waiting times are derived using the rate conservation principle and the work conservation law. The characteristics of this model, such as the mean waiting times at both queues and their ratio, can be controlled by changing the parameter K ; for example, when K is one, the model corresponds to a non-preemptive priority model. Because mixtures of service disciplines can yield various priority relations between queues, the performance of these disciplines should be evaluated in constructing an integrated services system.

Sojourn time distributions in the queue defined by a general QBD process

We consider a general QBD process as defining a FIFO queue and obtain the stationary distribution of the sojourn time of a customer in that queue as a matrix exponential distribution, which is identical to a phase-type distribution under a certain condition. Since QBD processes include many queueing models where the arrival and service process are dependent, these results form a substantial generalization of analogous results reported in the literature for queues such as the PH/PH/c queue. We also discuss asymptotic properties of the sojourn time distribution through its matrix exponential form.

Asymptotics for the stationary distribution in a discrete-time two-dimensional quasi-birth-and-death process

We consider a discrete-time two-dimensional process

Analysis of queues with Markovian service processes

\{(L_{n}^{(1)},L_{n}^{(2)})\}

Method of Bandwidth Dimensioning and Management for Aggregated TCP Flows with Heterogeneous Access Links

on

Bounds of performance measures in large-scale mobile communication networks

\mathbb{Z}_{+}^{2}

A measurement-based performance evaluation method for IP networks and its implementation

with a background process {Jn} on a finite set, where individual processes

Exact asymptotic formulae of the stationary distribution of a discrete-time two-dimensional QBD process

\{L_{n}^{(1)}\}

A method of bandwidth dimensioning and management for aggregated TCP flows with heterogeneous access links

and

Analysis of a multiqueue model for an ISDN access interface

\{L_{n}^{(2)}\}