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Browse Prior Art Database

Analytical Modeling System

IP.com Disclosure Number: IPCOM000111489D
Original Publication Date: 1994-Feb-01
Included in the Prior Art Database: 2005-Mar-26
Document File: 2 page(s) / 97K

Publishing Venue

IBM

Related People

Hanschke, T: AUTHOR [+2]

Abstract

The economical operation of a manufacturing system requires careful planning of resources and layout. To guarantee an optimal material flow and to achieve a high amount of flexibility, it is essential to detect and eliminate the bottlenecks of a manufacturing line. With increasing complexitiy of manufacturing processes, it is more and more difficult to understand material and information flow and to find the right methods for answering questions concerning performance or costs of such an environment. Therefore, computer-based applications to design and control manfacturing systems became very important in the past.

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Analytical Modeling System

      The economical operation of a manufacturing system requires
careful planning of resources and layout.  To guarantee an optimal
material flow and to achieve a high amount of flexibility, it is
essential to detect and eliminate the bottlenecks of a manufacturing
line.  With increasing complexitiy of manufacturing processes, it is
more and more difficult to understand material and information flow
and to find the right methods for answering questions concerning
performance or costs of such an environment.  Therefore,
computer-based applications to design and control manfacturing
systems became very important in the past.

      The AMS, the Analytical Modeling System, is one of these
applications.  The special feature of AMS is its method: it is not
based on the classical descrete event simultation used by almost all
other planning tools; rather, it is based on an analytical approach
developed from queueing theory.

      The applied mathematical algorithm for calculating the
characteristics of the underlying queueing process is based on a
decomposition method, i.e., any subsystem is described by a
multi-server batch queue in which all inter-arrival and service times
are independent and identically distributed random variables.  The
approximation formulae for the performance measures of the
batch-queueing systems have been derived with the aid of a diffusion
approximation technique.  The machine breakdowns and their subsequent
repairs are treated as so-called active interruptions (interruption
only when the server is active) and are simulated by appropriately
refining the parameters of the service times.  In order to compute
the parameters of the inter-arrival time distributions at each work
center, we slightly generalized the well-known decomposition method,
which results in two systems of linear equations for determining the
mean, the variance of the inter-arrival time distributions.

      AMS is an IBM internal PS/2* software package for the OS/2*
Presentation Manager* for planning and dimensioning manufacturing
systems.  It can model lines with multiple product types, and it
directly calculates the maximum possible throughput, the equipment
utilization, actual leadtimes and buffers needed for a given
production plan.  All results can be displayed or printed in the form
of tables or graphical plots.  Also, AMS can be used to perform a
direct capacity calculation which is important in the design phase of
a manufacturing line.

      An AMS model consists of work centers, products and operations
and a process flow for each product.

      Work centers are used to model working places or machine
groups.  The major param...