PEGS Production Scheduler

Beta Version released (20/9/2005) (Current version is Version 2.0.3)

Company Partners needed for Trials and Case Studies

Introduction

Production scheduling programs are used by companies to determine the best order in which to manufacture their products. The aim is to optimise the order of production against some pre-determined goal such as minimum production time, maximum utilisation of equipment or minimum average lateness for deliveries to customers.

Our new scheduler, PEGS, uses the latest techniques for ordering and searching through millions of potential alternative schedules to find a solution close to the optimum possible.

The program is generic - it will cope with a wide range of factory configurations and manufacturing strategies including single machine, parallel machines, flow and job shops. Most operations fall within one of these categories.

Users set up the program by entering one-off details about their products, factory equipment, production operations and the sequence of operations needed to make each product. Where appropriate, the program can also store and use details of machine set-up times and account for between-operation buffer stocks of partly processed products.

To create a schedule it is then necessary to enter details of when the various machines will become available and a list of orders (quantities of products to be made) and possibly due dates for those orders. Next, choose the objective, say to minimise total production time, and run the program. The results are displayed on a Gannt chart (showing which operation is running on which machine against time) and may be printed out in various formats.

All the details can be saved on disk and can be reloaded at any time to generate alternative or follow-on schedules.

Benefits

The main benefit is likely to be an improvement in operating efficiency arising from the use of optimised schedules over those generated by hand or using less effective scheduling programs.

In one case study with a local manufacturer PEGS produced schedules with completion times about 15% shorter over a four-week period. In this case the objective was to improve machine utilisation and hence increase the potential total weekly output of the factory.

The degree of benefit realised from a scheduler depends on the individual circumstances of the client company. It is most likely to be of benefit where there are many different products or batches to be made on a range of machines and there is a need to improve machine or staff utilisation, factory throughput, to reduce the amount of work in progress, or to improve on the ability to meet due dates.

Company Partners needed for Trials and Case Studies

The first 'beta' or test version of the new PEGS program was released on the 20th September 2005. In order to test the new program in real situations, we need a number of industrial partners to try it out. Local Northern Ireland companies are particularly welcome to take part in the trials.

We will visit your company and help to set up the program and show your staff how to use it. In exchange for this, we wish to examine the results from the program and to check that it does indeed produce improved production schedules.

At the end of the trial participating companies will have an option to buy the program at an agreed discount should they wish to continue using it.

If you'd like to get involved contact John Stewart at: j.r.stewart@qub.ac.uk

Beta Version released (20/9/2005)

A 'beta' or initial test version of the new PEGS program is now available.

Case Studies

As soon as we have them, we intend to add details of some case studies illustrating practical applications of the program.

Program Details

This section contains some technical details for readers interested in those aspects.

PEGS (Production and Environmental Generic Scheduler) is a finite capacity generic production scheduling system. PEGS can solve Single, Parallel or Job Shop/Flow Shop environments.

Two systems for PEGS have now been developed, both available in the current beta version. The default is now to use an agent-based system to schedule. This is distributd in nature but runs on a single machine. It uses software agents to represent machines and jobs, where they negotiate to generate the best schedule. We also have a centralised system. This uses the popular Shifting Bottleneck algorithm along with a choice of search strategy to generate a schedule. Tests show that the agent-based system can be much faster in a Job Shop environment. Both systems use exactly the same data and have the same functionality. They just schedule differently. Simply click a check box to change between the two systems.

Being generic, PEGS offers a wide choice of evaluation objective (e.g. makespan, flowtime, tardiness, etc.). Other features include setup times and a wide range of machine, time and job constraints. PEGS is stand alone, reading input from XML files or, in the case of job details, also from CSV files.

PEGS allows overlap of operations for the same job while others are in sequence. It has a simple buffer that also allows one operation to start after a fixed number of items of the previous operation for the same job has finished. PEGS will automatically group similar operations based on type/family, or waste type/family, to try to improve the objective. PEGS has an accumulative operation that can take input from several jobs, process it and then schedule the resulting output to several jobs again.

Few companies are in a position to extrapolate from their production plans to predict their environmental performance. The PEGS scheduling program will not only make both economic and environmental predictions, but will permit optimisation of work programmes to minimise costs and environmental burdens.

Environmental factors can be evaluated as part of the schedule. Currently we have implemented facilities to account for operator numbers, energy usage and waste produced. When evaluating waste the objectives are converted into economic equivalents, requiring some relatively simple economic factors about the plant to be entered.

Because using search strategies to generate a schedule can sometimes be quite slow, we have developed a distributed version that allows you to spread the scheduling among a number of machines. This option is only available if using the centralised Shifting Bottleneck algorithm, as it is this algorithm that is distributed. If using the agent-based system, then this is much quicker anyway for a Job Shop and so does not need to be distributed.

PEGS has two main windows. The Data Entry window allows manual entry of the relevant factory details, which can then be saved in a project file for automatic re-use at a later time.

Standard processing sequences can be entered but they may later be overridden by entering fixed times and alternative routes for particular jobs. The Data Entry window also allows re-scheduling because of breakdowns or new job entries.

The other main window is the Schedule window, which displays the schedule as a Gantt chart. This is fully interactive allowing you to move operations to other machines or before other operations and re-schedule with this change.

The program comes with an Acrobat format (.pdf) operating manual and a 'getting started' guide, which may be viewed on screen or printed, as well as having the same information available as interactive program help files.

Sample Screenshots

Main Data Entry Window

Schedule Window

Trial Version

QTL have developed a trial version of the PEGS program to let potential users evaluate the program at first hand. The trial version is fully functional but allows job details to be entered for the dates up to the end of 2006 only.

Before you can install the PEGS system, you need to make sure that you have the .Net framework installed on your computer. You can check to see if you already have the .NET Framework 1.1 installed by clicking Start on your Windows desktop, selecting Control Panel, and then double-clicking the Add or Remove Programs icon. When that window appears, scroll through the list of applications. If you see Microsoft .NET Framework 1.1 listed, the latest version is already installed and you do not need to install it again. If it is not installed, you can download it from here.

To download a trial version of PEGS click here.

The .Net framework is language specific. We have included the English language version in another demo version zip file. To download a trial version with the English version of the .Net redistributable included in the zip file click here.

If you want to test the distributed version, you also need to download the server application from here.

Read the readme file included in the zip file before installing.

Version Changes

Please note that from version 1.9.4 onwards, the economic factors are stored differently. If using data from earlier versions, you will need to re-enter the economic factors again.

Consultancy

As with all our products QUESTOR Technologies provides a consultancy service for PEGS.

For further information on our scheduling consultancy service please contact:

John Stewart
The QUESTOR Centre
The Queen's University of Belfast
BT9 5AG
Phone: +44 (0)28 9097 4037
E-mail: j.r.stewart@qub.ac.uk

How to obtain the software

A full release version is available for purchase at a price of £2500 plus VAT. If you help with the development or testing of the system then discounts will be available. The planned release date is fourth quarter 2005. Please send your enquiries to:

Product Sales,
QUESTOR Technologies Ltd,
David Keir Building,
Stranmillis Road,
Belfast,
Northern Ireland,
BT9 5AG