Interactive event-based intelligent scheduling Rand Afrikaans by gyvwpsjkko


									Interactive event-based intelligent scheduling

                    Xiaomei Zhang


          submitted in fulfilment of the requirements
                        for the degree

                 Philosophiae Doctor


                  Computer Science

                            in the

                 Faculty of Science

                            of the

         Rand Afrikaans University

            Promoter: Prof EM Ehlers

                    September 2003


Table of contents

List of figures and tables



Published papers

Thesis body

List of sources consulted


Keywords: “intelligent scheduling”,       “integrated   scheduling”,    “knowledge-based

The present research study will be dedicated to expounding an integrated event-based
scheduling model, which model will, in turn, be based on an object-oriented method and
a knowledge-based methodology. In order to complete the said model, the integration of
vision and scheduling systems has been taken one step further, especially as far as the
processing of events, data integration and interface design are concerned. Consequent
upon the latter research, three knowledge-based domain schedulers will be expounded
as scheduling control mechanisms. For the completion of the integrated scheduling
system, scheduling strategies and methods based on general environments have been
developed further. A wide knowledge base model will also be introduced. Finally, a case
study based on the management and manufacturing environments of Omega Holdings
Ltd will be conducted with the help of the proposed new scheduling model. The author
hopes that the integrated event-based scheduling system will serve as an effective
scheduling system tool for manufacturing and industrial-management environments

This thesis comprises three sections, the first of which provides an overview of
scheduling literature, including scheduling types, methods and technologies in a
manufacturing environment. The first section will also be dedicated to a discussion on
current approaches to scheduling and their respective limitations, followed by the
introduction of an integrated scheduling model for interactive event-based intelligent
scheduling. This will be followed by a detailed function analysis of the model in question,
based on its architecture.

The second section holds the key to this thesis, as it will be dedicated to a discussion on
knowledge-based domain schedulers for interactive scheduling, the implementation of
three knowledge-based domain schedulers based on an object-oriented concept and
event-based scheduling strategies. Consequent upon this discussion, the model of a
wide integrated knowledge base will be developed further.
Finally, an interactive event-based intelligent scheduling system will be developed for a
dynamic manufacturing environment, whereupon an evaluation of the proposed
scheduling tool and system will be effected. A case study undertaken in an existing
holding company will then be used to illustrate how to realise interactive event-based
intelligent scheduling and how to improve on the management function in a dynamic

The thesis will culminate in a summary of the pros and cons of the proposed system.
In conclusion, an indication will be given as to possible areas for future research, such as
multilayer scheduling in a distributed environment.


Sleutelwoorde:    “intelligente skedulering”, “geïntegreerde skedulering”,
                  “kennisgebaseerde skedulering”

Die onderhawige navorsingstudie word gewy aan die uiteensetting van ’n geïntegreerde
gevalgebaseerde skeduleringsmodel, welke model op sy beurt op ’n objekgeoriënteerde
metode en ’n kennisgebaseerde metodologie berus. Ten einde gemelde model te kon
voltooi, is die integrasie van ’n visie- en skeduleringstelsel een stap verder gevoer, veral
wat die verwerking van gevalle, data-integrasie en koppelvlakontwerp betref.
Voortspruitende    uit   laasgenoemde       navorsing     word    drie    kennisgebaseerde
domeinskeduleerders          as       skeduleringskontrolemeganismes            uiteengesit.
Skeduleringstrategieë en -metodes gebaseer op algemene omgewings is verder
ontwikkel ten einde die geïntegreerde skeduleringstelsel te voltooi. ’n Wyekennisbasis-
model word ook bekendgestel.         Ten slotte word ’n gevallestudie gebaseer op die
bestuurs- en vervaardigingsomgewing van Omega Beherend Beperk met behulp van die
voorgestelde nuwe skeduleringsmodel onderneem.                 Die outeur hoop dat die
geïntegreerde      gevalgebaseerde        skeduleringstelsel     as      ’n   doeltreffende
skeduleringstelselinstrument vir sowel vervaardigings- as bedryfsleidingsomgewings sal

Hierdie verhandeling bestaan uit drie afdelings, waarvan die eerste ’n oorsig oor
skeduleringsliteratuur verskaf, met inbegrip van skeduleringstipes, -metodes en
-tegnologieë binne ’n vervaardigingsomgewing. Die eerste afdeling word voorts gewy
aan ’n bespreking rondom bestaande benaderings tot skedulering en hierdie benaderings
se onderskeie beperkings, gevolg deur die bekendstelling van ’n geïntegreerde

skeduleringsmodel    vir   interaktiewe   gevalgebaseerde     intelligente   skedulering.
Laasgenoemde word gevolg deur ’n gedetailleerde funksie-ontleding van die betrokke
model, gegrond op die model se argitektuur.

Die tweede afdeling bevat die sleutel tot hierdie verhandeling, aangesien dit gewy word
aan ’n bespreking rondom kennisgebaseerde domeinskeduleerders vir interaktiewe
skedulering, die implementering van dtie kennisgebaseerde domeinskeduleerders
gegrond op ’n objekgeoriënteerde konsep en gevalgebaseerde skeduleringstrategieë.

Voortspruitende uit gemelde bespreking word die model van ’n wye geïntegreerde
kennisbasis verder ontwikkel.

Ten slotte word ’n interaktiewe gevalgebaseerde intelligente skeduleringstelsel vir ’n
dinamiese vervaardigingsomgewing ontwikkel, waarna ’n evaluering van die voorgestelde
skeduleringsinstrument en -stelsel uitgevoer word.     ’n Gevallestudie wat binne ’n
bestaande beheermaatskappy onderneem is, word daarna gebruik om aan te toon hoe
interaktiewe gevalgebaseerde intelligente skedulering geïmplementeer word en hoe die
bestuursfunksie in ’n dinamiese omgewing verbeter kan word.

Die onderhawige verhandeling kulmineer in ’n opsomming van die voor- en nadele van
die voorgestelde stelsel. Ter afsluiting word ’n aanduiding gegee van gebiede wat hulle
moontlik tot verdere navorsing sal kan leen, soos dié van multivlakskedulering in ’n
verspreide omgewing.



Index         Description                                                   Page No

Chapter 0 Preamble                                                           0-1
0.1           Principal aim                                                  0-2
0.2           Scope                                                          0-2
0.3           Layout                                                         0-2

Part – I      Scheduling overview and
              the integrated scheduling model
Chapter 1 Introduction                                                       1-1
1.1           Introduction                                                   1-2
1.2           The scheduling problem and its background                      1-2
1.2.1         Introduction                                                   1-2
1.2.2         Characteristics                                                1-3
1.2.3         Objectives                                                     1-3
1.2.4         Essential ingredients of successful production management      1-4
1.2.5         Environment of scheduling problems                      1-4
1.3           Defining scheduling                                            1-5
1.4           Scheduling systems                                             1-7
1.5           The solution to scheduling problems                            1-8
1.6           Summary                                                        1-9

Chapter 2 A survey of scheduling literature
2.1           Introduction                           `                       2-2
2.2           Scheduling terminology                                         2-3
2.3           Classification of scheduling applications                      2-7
2.4           Scheduling methods                                             2-10
2.5           Scheduling technology                                          2-13
2.5.1         Traditional scheduling                                 2-13
2.5.2         Recent scheduling technologies                                 2-14

2.6      Scheduling strategies                                         2-15
2.7      Summary                                                       2-16

Chapter 3 Descriptions and requirements of scheduling
          problems                                                     3-1
3.1      Introduction                                                  3-2
3.2      The classification of scheduling problems                     3-3
3.2.1    Classification by means of resource types                     3-4
3.2.2    Classification by means of constraints                        3-5
3.2.3    Classification by means of requirements                       3-6
3.2.4    Classification by means of nature                             3-7
3.2.5    Classification by means of feature                            3-7
3.2.6    A proposed EPRCER classification scheme                       3-7
3.3      The comparison of specific scheduling problems                3-11
3.3.1    The relationships among specific scheduling problems          3-11
3.3.2    Definition and differences                                    3-12
3.4      The features and requirements of scheduling problems          3-17
3.4.1    Common features of scheduling problems                        3-17
3.4.2    Common requirements                                           3-18
3.5      The specific scheduling problem to be discussed               3-19
3.6      Summary                                                       3-20

Chapter 4 Manufacturing environment                                    4-1
4.1      Introduction                                                  4-2
4.2      Classification of a manufacturing environment                 4-3
4.3      Computer-integrated manufacturing environment                 4-6
4.3.1    CIME representations                                          4-6
4.3.2    Manufacturing system                                          4-8
4.4      An analysis of the physical environments of a
         manufacturing system                                4-9
4.4.1    A functional representation                         4-9
4.4.2    An object-oriented representation                   4-11
4.4.3    A knowledge-based representation                    4-12
4.5      A complete knowledge-based approach for ME analysis 4-13
4.6      Summary                                             4-14

Chapter 5 Scheduling systems                                           5-1
5.1      Introduction                                                  5-2
5.2      Description of a scheduling system                            5-3
5.3      Reviews of knowledge-based scheduling systems                 5-6
5.3.1    Object-oriented scheduling system (“OOSS”)                    5-8
5.3.2    Constraint-based scheduling system (“CBSS”)                   5-9
5.3.3    Hybrid scheduling system (“HSS”)                              5-11
5.3.4    Integrated scheduling system (“ISS”)                   5-12
5.4      Comparison of scheduling system architecture                  5-13
5.4.1    Conceptual architecture                                       5-13
5.4.2     Strategic architecture                                  5-14
5.4.3     Generalised architecture                                5-14
5.5       A general intelligent scheduling system                 5-16
5.5.1     Characteristics                                         5-16
5.5.2     Framework and basic modules                             5-16
5.5.3     Development cycle                                       5-21
5.6       Summary                                                 5-24

Chapter 6 The Integrated Scheduling Model                         6-1
6.1       Introduction                                            6-2
6.2       Overview of related production control systems          6-3
6.2.1     Master production schedule (“MPS”)                      6-3
6.2.2     Manufacturing resource planning (“MRP-II”)              6-4
6.2.3     Event-based scheduling                                  6-6
6.3       Object-oriented method and approach                     6-7
6.4       The framework of the Integrated Scheduling Model        6-8
6.5       Description of the Model                                6-13
6.5.1     Physical environment layout class                       6-13
6.5.2     Master production scheduler class                       6-13
6.5.3     Material requirement scheduler class                    6-14
6.5.4     Capacity requirement scheduler class                    6-15
6.5.5     Visual-event analyser class                             6-17
6.5.6     Total environment manager class                         6-18
6.5.7     Integrated schedule class                               6-19
6.6       Summary                                                 6-22

Part – II The completion of the model
Chapter 7 Integration of scheduling and supervision
          systems                                                 7-1
7.1       Introduction                                            7-2
7.2       The strategy of integration                             7-4
7.2.1     An integrated scheduling strategy                       7-4
7.2.2     Description of the strategy of integration              7-6   Integration on a production activity level              7-6   Hardware interface connection and the use of software   7-9   Integration of data and knowledge                       7-10
7.3       Different methods of integration                        7-11
7.3.1     The general integration method                          7-11   Description of the method                               7-11   The application of the method                           7-12

7.3.2     The Method of Object-oriented Integration                 7-13
7.4       Integration of scheduling and vision systems              7-15
7.4.1     A conceptual framework of the integration                 7-15
7.4.2     A functional framework of the integration                 7-16
7.5       The interfaces for scheduling and vision systems          7-18
7.5.1     The detector interface                             7-18
7.5.2     The visual-event interface                                7-19
7.5.3     The physical interface                             7-19
7.6       Visual-event process and data integration                 7-20
7.6.1     Visual-event acquisition                                  7-20
7.6.2     Visual-event processing and integration                   7-20
7.6.3     Visual-data extractor (dynamic classification)            7-21
7.6.4     Visual-data analyser (static classification)              7-21
7.6.5     Image recogniser                                          7-21
7.6.6     Image knowledge base                                      7-21
7.6.7     A diagram of visual-event processing                      7-22
7.7       Evaluation of the vision integration                      7-23
7.8       Summary                                                   7-24

Chapter 8 The knowledge-based schedulers                            8-1
8.1       Introduction                                              8-2
8.2       A description of schedulers                               8-4
8.2.1     Position of schedulers                                    8-4
8.2.2     Features and functions                                    8-6
8.2.3     Hierarchical function analysis                     8-8
8.2.4     Integration of schedulers                          8-10
8.2.5     Interface of schedulers                            8-11
8.3       A model of domain schedulers                       8-12
8.3.1     A knowledge-based model                            8-13
8.3.2     Description of the model                           8-13   A description of function modules                  8-13   Domain Event Control Interface (“DECI”)            8-14   Internal state                                     8-16   Integrated Information Net (“IIN”)                 8-17   Domain Event Processor (“DEP”)                     8-17   Domain Negotiation Controller (“DNC”)              8-19   Domain Schedule Dispatcher (“DSD”)                 8-20
8.4       The knowledge-based WMPS                           8-21
8.4.1     Scheduling process description                     8-21
8.4.2     Integrated central scheduling strategies           8-23
8.5       KB Master Production Schedule Scheduler (“KBMPSS”) 8-24
8.5.1     Scheduling process description                     8-24
8.5.2     Dynamic master scheduling strategies               8-25
8.6       KB Material Resource Plan Scheduler (“KBMRPS”)     8-27
8.6.1     Scheduling process description                     8-27
8.6.2     Material resource scheduling strategies            8-28
8.7       KB Capacity Resource Plan Scheduler (“KBCRPS”)     8-29
8.7.1     Scheduling process description                     8-29
8.7.2     Dynamic capacity scheduling strategies                            8-30
8.8       Summary                                                           8-32

Chapter 9 A model of a wide integrated knowledge base                       9-1
9.1       Introduction                                                      9-2
9.2       Definition of the terms “data”, “knowledge” and “rule”            9-3
9.2.1     Data and databases                                                9-4
9.2.2     Knowledge and knowledge base                                      9-5
9.2.3     Rule and rule base                                                9-6
9.2.4     Relationship between data, knowledge and rule                     9-6
9.3       An integrated database model                                      9-8
9.3.1     Classification                                                    9-8
9.3.2     Database structure                                                9-9
9.3.3     Data format                                                       9-9
9.3.4     Data-type definition                                              9-11
9.3.5     The method for integrating data                                   9-14
9.4       An integrated rule-base model                                     9-15
9.4.1     Classification of the integrated rule base                        9-15
9.4.2     Rule sources and integration of the integrated rule base          9-16
9.4.3     The structure and format of the integrated rule base       9-16
9.5       An integrated knowledge-base model                                9-17
9.5.1     Classification                                                    9-17
9.5.2     Detailed description of an integrated knowledge base              9-18
9.6       A wide integrated knowledge-base model                            9-19
9.7       Summary                                                           9-20

Part – III Developing an integrated scheduling system,
           case study and conclusion
Chapter 10 Developing an integrated scheduling system                       10-1
10.1      Introduction                                                      10-2
10.2      Interactive event-based intelligent scheduling                    10-3
10.3      A dynamic scheduling tool                                         10-4
10.4      Description of the integrated scheduling system                   10-6
10.5      A scheduling clock                                                10-9
10.6      Other factors to consider when implementing an
          integrated system                                                 10-11
10.7      Summary                                                           10-12

Chapter 11 A case study: Omega Holdings Ltd                                 11-1
11.1      Introduction                                                      11-2
11.2      Omega Holdings Limited: an introduction                           11-2
11.3      Omega’s management levels                                         11-4
11.4      Omega’s scheduling levels and problems                            11-7

11.4.1          Omega’s scheduling levels                                     11-7
11.4.2          Omega’s internal problems                                     11-9
11.5            Scheduling solutions for Omega                                11-10
11.5.1          A new organisational structure for Omega                      11-10
11.5.2          A complete scheduling system framework                        11-11        Central scheduling and management system                      11-13        The Internet-based Scheduling Integration Centre              11-14        Distributed domain scheduling                                 11-14        Local domain scheduling                                       11-15
11.6            Developing scheduling mechanism and solution                  11-15
11.6.1          Developing central manager and domain managers        11-15
11.6.2          Developing schedulers                                         11-15
11.6.3          Developing a database, knowledge base and rule base           11-16        Database                                                      11-16        Knowledge base                                                11-17        Rule base                                                     11-18
11.7            Summary                                                       11-19

Chapter 12 Evaluation
12.1            Introduction                                                  12-2
12.2            Evaluation of a scheduling problem                            12-2
12.2.1          Traditional scheduling problems                               12-3
12.2.2          Real-time scheduling problems                                 12-4
12.2.3          Dynamic scheduling problems                                   12-5
12.2.4          Rescheduling problems                                         12-5
12.2.5          Visual-event scheduling problems                              12-5
12.3            Evaluation of scheduling methods                              12-6
12.3.1          The OO Method                                                 12-6
12.3.2          The Functional Decomposition Method                           12-7
12.3.3          The Event-based Method                                        12-7
12.4            Evaluation of scheduling strategies                           12-8
12.5            Evaluation of knowledge-based schedulers                      12-8
12.6            Evaluation of database, knowledge base, rule base             12-9
12.6.1          Evaluation of the database                                    12-9
12.6.2          Evaluation of knowledge base and rule base            12-10
12.7            Evaluation of a scheduling system                             12-11
12.8            Summary                                                       12-12

Chapter 13 Conclusion                                                         13-1
13.1            Introduction                                                  13-2
13.2            Conclusion                                                    13-3
13.2.1          Realisation of main objectives                                13-3
13.2.2          Scheduling solution                                           13-4
13.2.3          Scheduling methods                                            13-5
13.2.4          Benefits to be derived from the newly expounded
                scheduling system                                             13-6

13.2.5           Additional benefits to be derived from the newly expounded
                 scheduling system                                                    13-7
13.2.6           Limitations of the newly expounded scheduling system                 13-8
13.3             Further research                                                     13-9
13.3.1           Potential areas for further research                                 13-9
13.4             Summary                                                              13-10

List of sources consulted



Figure/Table No Title of figure/table                                                Page No

Fig. 1.1         A functional layout of a scheduling system                           1-7
Fig. 1.2         The solution to a scheduling problem                         1-9
Fig. 2.1         The procedure for developing a scheduling strategy           2-17
Fig. 3.1         A proposed broader definition of scheduling                  3-8
Table 3.1        The proposed EPRCER classification of scheduling problems            3-10
Fig. 3.2         The classification of and relationships among specific
                 scheduling problems                                                  3-11
Fig. 4.1         A hierarchical representation of a CIME                              4-7
Fig. 4.2         A functional representation of a CIME                                4-8
Fig. 4.3         The functional representation of a physical environment              4-10
Fig. 4.4         An object-oriented representation of a physical environment          4-11
Fig. 4.5         A source viewed as an object                                4-12
Fig. 4.6         A knowledge-based representation of a physical environment           4-13
Fig. 4.7         A complete knowledge-based approach to an ME analysis                4-14
Fig. 5.1         Relationship between production-management systems                   5-5
Fig. 5.2         A graphic representation of a knowledge-based scheduling
Fig. 5.3         The conceptual architecture of a scheduling system                   5-14
Fig. 5.4         The strategic architecture of a scheduling system                    5-15
Fig. 5.5         The generalised architecture of a scheduling system                  5-15
Fig. 5.6         The general component representation of a scheduling system          5-17
Fig. 5.7         Scheduling system development cycle (based on [EAS94]) 5-22
Fig. 6.1         MRP-II conceptual diagram based on [WIG88]                           6-5
Fig. 6.2         The relationship between a vision system and manufacturing
                 control                                                              6-6

Fig. 6.3      The procedure followed when utilising the OO system method          6-9
Fig. 6.4      The framework for an integrated scheduling model                    6-10
Fig. 6.5      A graphic representation of the MPS scheduler class                 6-14
Fig. 6.6      A graphic representation of the MRP scheduler class                 6-16
Fig. 6.7      A graphic representation of the CRP scheduler class                 6-17
Fig. 6.8      A graphic representation of the visual-event analyser class 6-18
Fig. 6.9      The data flow inside an integrated schedule                         6-21
Fig. 7.1      An integrated scheduling strategy                                   7-5
Fig. 7.2      A general integrated method                                         7-12
Fig. 7.3      A method of object-oriented integration                             7-14
Fig. 7.4      A conceptual framework of the integration                           7-16
Fig. 7.5      A functional framework of integration                        7-17
Fig. 7.6      The object-oriented representation of a detector interface          7-19
Fig. 7.7      A diagram of visual-event processing                                7-22
Fig. 8.1      A graphic depiction of schedulers at three scheduling levels        8-5
Fig. 8.2      A graphic representation of the parts the three schedulers play     8-7
Fig. 8.3(a)   The multilayered integrated function of schedulers                  8-9
Fig. 8.3(b)   The multilayered dispatch function of schedulers                    8-9
Fig. 8.4      Integration of schedulers                                           8-10
Fig. 8.5      Integration interface of schedulers                                 8-11
Fig. 8.6      MPSS domain interface                                               8-12
Fig. 8.7      Structure of knowledge-based domain schedulers                      8-13
Fig. 8.8      Event evaluation module                                             8-18
Fig. 8.9      Domain negotiation controller                                8-19
Fig. 8.10     An OO management method for processing events                8-24
Fig. 8.11     A strategy for releasing constraints, based on [KOL93]              8-26
Fig. 8.12     Scheduling process of KBMRPS                                        8-28
Fig. 8.13     Co-ordination framework of the scheduling process                   8-29
Fig. 9.1      Data, knowledge and rule relationships in the system                9-5
Fig. 9.2      The information-transformation process                              9-7
Fig. 9.3      The Integrated Database Model                                       9-9
Fig. 9.4      Database structure                                                  9-10
Fig. 9.4(a)   Data contents structure                                             9-11
Fig. 9.5      An integrated rule-base model                                       9-15
Fig. 9.6      Rule-base structure                                                 9-16
Fig. 9.7      An integrated knowledge-base model                                  9-18
Fig. 9.8      A wide integrated knowledge-base model                              9-19
Fig. 10.1     A model of a dynamic scheduling tool                                10-4
Fig. 10.2     A functional representation of the integrated scheduling system     10-7
Fig. 11.1     Goods controller flow                                               11-4
Fig. 11.2     Goods flow                                                          11-4
Fig. 11.3     Omega management organisational structure                           11-6
Fig. 11.4     New proposed organisational structure for Omega                     11-11
Fig. 11.5     A complete scheduling system framework for Omega                    11-13
Fig. 12.1     Factors to be evaluated for a special scheduling problem            12-3

 Legend used in figures
 The following notation is used in all figures, unless indicated otherwise:

                           -       Data flow
                           -       Message flow
                           -       Extended message flow


3D             Three-dimensional
ACCPAC         Accounting Package
AI             Artificial Intelligence
ASCII          American Standard Code for Information Interchange
BOM            Bill of materials
CBSS           Constraint-based Scheduling System
CE             Conceptual environment
CEO            Chief Executive Officer
CIM            Computer-integrated manufacturing
CKB            Central knowledge base
CIME           Computer-integrated manufacturing environment
CIMS           Computer-integrated manufacturing system
CRP            Capacity requirement (resource) plan (planning)
CRPKB          Capacity resource plan knowledge base
CRPS           Capacity resource plan scheduling/
               Capacity resource plan scheduler
CRPSD          Capacity resource plan scheduling domain
CSMS           Central scheduling and management system
DB             Database
DECI           Domain event control interface
DEP            Domain event processor
DNC            Domain negotiation controller
DSD            Domain schedule dispatcher
ED             Events dispatched
EDC            Events dispatched from the controller
EDP            Events dispatched from the processor
EDI            Dispatched Internal Events
EDIS           Events dispatched from internal state
EE             Events external
EI             Events internal
EPRCER         Event-Priority-Resource-Constraint-Environment-Requirement

ER       Events rescheduled
ES       Expert system
EU       Events updated
Ec       Events for capacity domain
Ef       Events for final dispatch
Em       Events for material domain
Eo       Events for rescheduling
Ep       Events for production
FAS      Final assembly scheduling
FIFO     First in, first out
FME      Flexible manufacturing environment
FMS      Flexible manufacturing system
FMSE     Flexible manufacturing system environment
HSS      Hybrid scheduling system
IBSIC    Internet-based scheduling integration center
ISS      Integrated scheduling system
IT       Information Technology
IIN      Integrated Information Net
IKB      Integrated knowledge base
JIT      Just-in-time
KB       Knowledge base
KBMRPS   Knowledge-based Material Resource Plan Scheduler
KBMRS    Knowledge-based Material Requirement Scheduler
KBMPS    Knowledge-based Master Production Scheduler
KBMPSS   Knowledge-based Master Production Schedule Scheduler
KBCRPS   Knowledge-based Capacity Resource Plan Scheduler
KBCRS    Knowledge-based Capacity Requirement Scheduler
KBSS     Knowledge-based Scheduling System
LAN      Local Area Network
MA       Multiagent
ME       Manufacturing environment
MRP      Material Requirement (Resource) Plan (Planning)
MRPKB    Material Resource Plan Knowledge Base
MRPS     Material Resource Plan Scheduling
         Material Resource Plan Scheduler
MRPSD    Material Resource Plan Scheduler Domain
MPS      Master Production Schedule
MPSKB    Master Production Schedule Knowledge Base
MPSS     Master Production Schedule Scheduling/
         Master Production Schedule Scheduler
MPSSD    Master Production Schedule Scheduling Domain
MRP-II   Manufacturing Resource Planning-II
NN       Neural network
OO       Object-oriented
OOSS     Object-oriented scheduling system
OPT      Optimised Production Technology
OR       Operations Research
OCME     Source-Customer Manufacturing Environment
OSCME    Source-Stock-Customer Manufacturing Environment
PE       Production Environment

RE             Real Environment
SCCI           Shanghai Corporate Centre International
SCME           Stock-Customer Manufacturing Environment
SE             Simulated Environment
SSCME          Stock-Stock-Customer Manufacturing Environment
Sub-FE         Sub-function Environment
Sub-ME         Sub-manufacturing Environment
WIP            Work-in-process
WMPS           Wide Master Production Schedule (Scheduler)
WMPSS          Wide Master Production Schedule Scheduler
WMPSSD         Wide Master Production Schedule Scheduling Domain


This thesis would not have been possible without the help of a host of people, among
whom I would like to single out the following:

Ø      Prof EM Ehlers, for her guidance and her unwavering encouragement and

Ø      The NRF, for its financial support.

Ø      Mrs Ina Erasmus, for her support, her friendship and her truly caring attitude.

Ø      Mr Emil Marais, for his technical advice and guidance.

Ø      My parents, brother and sisters, whose love and enthusiasm made this a
       worthwhile undertaking.

Ø      My business partner, Mr RMH Havard, for his unflagging zeal and practical
       support, which took so many forms.

Xiaomei Zhang
September 2003


1.   “An integrated scheduling model for a manufacturing environment”, E.M. Ehlers, X. Zhang:
     Rand Afrikaans University, South Africa. Published on ICC & IE’96, Proceedings of the 20th
     International Conference on Computers & Industrial Engineering, Vol. 2, 6-9 October 1996,

2.   “Distributed   architecture   towards   integrated   scheduling”,    E.M.   Ehlers,   X.   Zhang:
     Page 646-653, CARS & FOF 2001, Proceedings of the 17 International Conference on
     CAD/CAM, Robotics and Factories of the Future, Durban, South Africa, 10-12 July 2001.
     ISBN 1-86840-432-3

3.   “Domain schedulers for wide master production schedulers”, E.M. Ehlers, X. Zhang:
     Page 654-661, CARS & FOF 2001, Proceedings of the 17th International Conference on
     CAD/CAM, Robotics and Factories of the Future, Durban, South Africa, 10-12 July 2001.
     ISBN 1-86840-432-3


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