ABSTRACT

In order to evaluate the performance of several scheduling policies for
multiclass  queuing  networks  we felt  the need  to develop  a general
purpose software  package where different  networks and policies can be
tried, either  from a set  of pre-defined  systems and policies  or for
user-defined systems  and policies. In  this paper we present a package
to perform  discrete  event  simulation of a  manufacturing system with
different  configurations  specified  by the  user,  according  to  the
framework  of activity  networks  as introduced  by  Harrison [1].  The
package uses  an object oriented  modelling technique. The  language in
question is JAVA.

The architecture  of the system  to be simulated  is described  in file
format, where the resources,  routing patterns for customers, and other
parameters are  specified. The user  may choose the  decision  policies
from a library of methods or can add new  policies to this library. The
modelling flexibility  permitted includes  standard multiclass  queuing
networks to be modeled, where  there are a few types of customers, each
characterized  by a  unique  routing,  at each  stage  of  the  routing
customers  wait in  a specific  buffer for  the next  service, and each
server  works  on a customer  at a time.  The activity  networks  allow
other  configurations,  where  a given  service  may  take more  than a
customer  from  different  buffers. Some  preliminary  studies  on  the
performance   evaluation   of   distributed   scheduling  policies  for
queuing networks  are presented as a means  to provide insights  on the
type of utilization the package can have.