scheduling theory, algorithms, and systems

Scheduling




Michael L. Pinedo
Scheduling
Theory, Algorithms, and Systems
Fourth Edition

permission of the publisher (Springer Science+Business Media, LLC, 233 Spring Street, New York, NY
10013, USA), except for brief excerpts in connection with reviews or scholarly analysis. Use in connection
with any form of information storage and retrieval, electronic adaptation, computer software, or by similar
or dissimilar methodology now known or hereafter developed is forbidden.
The use in this publication of trade names, trademarks, service marks, and similar terms, even if they are
not identified as such, is not to be taken as an expression of opinion as to whether or not they are subject
to proprietary rights.
Printed on acid-free paper
Springer is part of Springer Science+Business Media (www.springer.com)
Springer New York Dordrecht Heidelberg London
ISBN 978-1-4614-1986-0 e-ISBN 978-1-4614-2361-4
DOI 10.1007/978-1-4614-2361-4
© Springer Science+Business Media, LLC 201
All rights reserved. This work may not be translated or copied in whole or in part without the written
Mathematics Subject Classification (2010):
Library of Congress Control Number:
2
68Mxx, 68M20, 90Bxx, 90B35
Michael L. Pinedo
New York

New York University
NY, USA
2011945105


To Paula,
Esti, Jaclyn, and Danielle,
Eddie, Jeffrey, and Ralph,
Franciniti, Morris, Izzy, and baby Michael.

H
F
r
W
pr
a
t
i
n
t
h
H
en
r
r
ed
e
W
ar
r

in
c
t
th
e
n
1
9
h
e
o
ry

L
e
ri
c
I t
o
c
i
p
l
e
e
a
n
9
18
.

o
ri
gi
L
a
u
ck

W
o

e
e
s
i
n
n
u
.
T
h
i
na
l
u
re
n
W
.
e

val
i
n
h
u
al
h
e
G
l
s,
b
n
ce
Ta
y
uat
h
is
me
e
G
a
n
b
ot
h
G
y
lo

r
e
p
p
a
p
e
ti
n
n
tt
c
h
i
n
H
E
ant
t
r
.
H
p
ro
d
p
er
ng

o

c
ha
r
n

pu
E
N
R
t

w
H
e
d
d
uc
t
“E
f
o
f
t
r
ts
c
u
r
po
R

Y
w
as
d
ev
e
t
io
n
f
fi
c
t
he
c
ur
r
o
se
L
A
(
1
a
n
e
lo
p
n
s

c
c
ie
n
A
m
r
en
an
d
A
U
R
1
86
1
n
i
n
p
e
d
c
he
d
n
c
y

m

er
i
tl
y

d
i
n
R
E
1
-1
9

n
du
d
hi
d
ul
e
an
d
i
ca
n
in
u
n
d

e
N
C
9
1
9
str
i
s n
o
e
s.
d

D
n
S
o
u
se
e
si
gn
C
E
G
9
)
i
al

o
w
G
a
D
e
m
o
ci
e
ar
e
n
.
GA
en
g
fa
m
a
ntt
m
oc
r
e
t
y

e
t

y
A
N
T
g
in
e
m
o
u
di
s
r
ac
y
of
yp
ic
T
T
e
er
u
s
c
s
cu
s
y
,”

M
e
all
y
a
n
c
ha
r
s
se
d
wh
e
ch
a
y
a
n
d
a
r
ts
d
d
t
h
ich
a
ni

c
si
m
a

d
d
u
r
h
e
u
h
e
c
al
mp
l
i
d
is
c
r
in
g
u
n
d
e

p
r
e
E
n
i
fic
a
c
i
p
l
e
g

W
d
erl
y
e
se
ng
i
n
a
ti
o
e

o

W
orl
d
y
in
g
nte
d
n
ee
r
o
n
o
o
f
d
g

d
r
s
o
f

Preface
Preface to the First Edition
Sequencing and scheduling is a form of decision-making that plays a crucial role
in manufacturing and service industries. In the current competitive environment
effective sequencing and scheduling has become a necessity for survival in the

market-place. Companies have to meet shipping dates that have been committed
to customers, as failure to do so may result in a significant loss of goodwill. They
also have to schedule activities in such a way as to use the resources available
in an efficient manner.
Scheduling began to be taken seriously in manufacturing at the beginning
of this century with the work of Henry Gantt and other pioneers. However, it
took many years for the first scheduling publications to appear in the industrial
engineering and operations research literature. Some of the first publications ap-
peared in Naval Research Logistics Quarterly in the early fifties and contained
results by W.E. Smith, S.M. Johnson and J.R. Jackson. During the sixties a
significant amount of work was done on dynamic programming and integer pro-
gramming formulations of scheduling problems. After Richard Karp’s famous
paper on complexity theory, the research in the seventies focused mainly on the
complexity hierarchy of scheduling problems. In the eighties several different
directions were pursued in academia and industry with an increasing amount
of attention paid to stochastic scheduling problems. Also, as personal comput-
ers started to permeate manufacturing facilities, scheduling systems were being
developed for the generation of usable schedules in practice. This system design
and development was, and is, being done by computer scientists, operations
researchers and industrial engineers.
This book is the result of the development of courses in scheduling theory and
applications at Columbia University. The book deals primarily with machine
scheduling models. The first part covers deterministic models and the second
part stochastic models. The third and final part deals with applications. In this
last part scheduling problems in practice are discussed and the relevance of
the theory to the real world is examined. From this examination it becomes
vii

viii Preface
clear that the advances in scheduling theory have had only a limited impact

on scheduling problems in practice. Hopefully there will be in a couple of years
a second edition in which the applications part will be expanded, showing a
stronger connection with the more theoretical parts of the text.
This book has benefited from careful reading by numerous people. Reha Uz-
soy and Alan Scheller Wolf went through the manuscript with a fine tooth comb.
Len Adler, Sid Browne, Xiuli Chao, Paul Glasserman, Chung-Yee Lee, Young-
Hoon Lee, Joseph Leung, Elizabeth Leventhal, Rajesh Sah, Paul Shapiro, Jim
Thompson, Barry Wolf, and the hundreds of students who had to take the (re-
quired) scheduling courses at Columbia provided many helpful comments which
improved the manuscript.
The author is grateful to the National Science Foundation for its continued
summer support, which made it possible to complete this project.
Michael Pinedo
New York, 1994.
Preface to the Second Edition
The book has been extended in a meaningful way. Five chapters have been
added. In the deterministic part it is the treatment of the single machine, the
job shop and the open shop that have been expanded considerably. In the
stochastic part a completely new chapter focuses on single machine scheduling
with release dates. This chapter has been included because of multiple requests
from instructors who wanted to see a connection between stochastic scheduling
and priority queues. This chapter establishes such a link. The applications part,
Part III, has been expanded the most. Instead of a single chapter on general
purpose procedures, there are now two chapters. The second chapter covers
various techniques that are relatively new and that have started to receive a fair
amount of attention over the last couple of years. There is also an additional
chapter on the design and development of scheduling systems. This chapter
focuses on rescheduling, learning mechanisms, and so on. The chapter with the
examples of systems implementations is completely new. All systems described
are of recent vintage. The last chapter contains a discussion on research topics

that could become of interest in the next couple of years.
The book has a website:
/>The intention is to keep the site as up-to-date as possible, including links to
other sites that are potentially useful to instructors as well as students.
Many instructors who have used the book over the last couple of years have
sent very useful comments and suggestions. Almost all of these comments have
led to improvements in the manuscript.
Reha Uzsoy, as usual, went with a fine tooth comb through the manuscript.
Salah Elmaghraby, John Fowler, Celia Glass, Chung-Yee Lee, Sigrid Knust,

Preface ix
Joseph Leung, Chris Potts, Levent Tuncel, Amy Ward, and Guochuan Zhang
all made comments that led to substantial improvements.
A number of students, including Gabriel Adei, Yo Huh, Maher Lahmar, Sonia
Leach, Michele Pfund, Edgar Possani, and Aysegul Toptal, have pointed out
various errors in the original manuscript.
Without the help of a number of people from industry, it would not have
been possible to produce a meaningful chapter on industrial implementations.
Thanks are due to Heinrich Braun and Stephan Kreipl of SAP, Rama Akkiraju
of IBM, Margie Bell of i2, Emanuela Rusconi and Fabio Tiozzo of Cybertec,
and Paul Bender of SynQuest.
Michael Pinedo
New York, 2001.
Preface to the Third Edition
The basic structure of the book has not been changed in this new edition.
The book still consists of three parts and a string of Appendixes. However,
several chapters have been extended in a meaningful way, covering additional
topics that have become recently of interest. Some of the new topics are more
methodological, whereas others represent new classes of models.
The more methodological aspects that are receiving more attention include

Polynomial Time Approximation Schemes (PTAS) and Constraint Program-
ming. These extensions involve new material in the regular chapters as well as
in the Appendixes. Since the field of online scheduling has received an enormous
amount of attention in recent years, a section focusing on online scheduling has
been added to the chapter on parallel machine scheduling.
Two new classes of models are introduced in the chapter on more advanced
single machine scheduling, namely single machine scheduling with batch pro-
cessing and single machine scheduling with job families.
Of course, as in any new edition, the chapter that describes implementations
and applications had to be revamped and made up-to-date. That has happened
here as well. Two new software systems have been introduced, namely a system
that is currently being implemented at AMD (Advanced Micro Devices) and a
generic system developed by Taylor Software.
For the first time, a CD-ROM has been included with the book. The CD-
ROM contains various sets of power point slides, minicases provided by com-
panies, the LEKIN Scheduling system, and two movies. The power point slides
were developed by Julius Atlason (when he taught a scheduling course at the
University of Michigan-Ann Arbor), Johann Hurink (from the University of
Twente in Holland), Rakesh Nagi (from the State University of New York at
Buffalo), Uwe Schwiegelshohn (from the University of Dortmund in Germany),
Natalia Shakhlevich (from the University of Leeds in England).

x Preface
A website will be maintained for this book at
/>The intention is to keep this website as up-to-date as possible, including links
to other sites that are potentially useful to instructors as well as to students.
A hardcopy of a solutions manual is available from the author for instructors
who adopt the book. The solutions provided in this manual have been prepared
by Clifford Stein (Columbia University), Julius Atlason (Michigan), Jim Geelen
(Waterloo), Natalia Shakhlevich (Leeds), Levent Tuncel (Waterloo), and Martin

Savelsbergh (Georgia Tech).
I am very grateful to a number of colleagues and students in academia who
have gone over the new sections and have provided some very useful comments,
namely Alessandro Agnetis (Siena), Ionut Aron (T.J. Watson Research Labo-
ratories, IBM), Dirk Briskhorn (Kiel), John Fowler (Arizona), Jim Geelen (Wa-
terloo), Johann Hurink (TU Twente, the Netherlands), Detlef Pabst (AMD),
Gianluca de Pascale (Siena, Italy), Jacob Jan Paulus (TU Twente, the Nether-
lands), Jiri Sgall (Charles University, Prague), and Gerhard Woeginger (TU
Eindhoven). Gerhard provided me with the chapters he wrote on Polynomial
Time Approximation Schemes. His material has been incredibly useful.
Without the help of a number of people from industry, it would not have
been possible to produce a meaningful chapter on industrial implementations.
Thanks are due to Stephan Kreipl of SAP, Shekar Krishnaswamy and Peng Qu
of AMD, and Robert MacDonald of Taylor Software.
The technical production of the book would not have been possible without
the invalualable help from Adam Lewenberg (Stanford University) and Achi
Dosanjh (Springer). Without the continued support of the National Science
Foundation this book would never have been written.
Michael Pinedo
Spring 2008
New York
Preface to the Fourth Edition
The text has undergone a number of enhancements and corrections. The presen-
tations and proofs of various results in Chapters 4 and 5 have been changed and
simplified. Chapter 6 now contains a new section that focuses on proportionate
flow shops. Chapter 19 contains a significant amount of new material as well;
two new sections have been added that describe the Asprova APS and the Pre-
actor scheduling systems. The other chapters have undergone minor changes;
however, a significant number of new references have been added in order to
keep the book up-to-date.

Preface xi
A website for this book is still being maintained on the author’s homepage
/>The intention is to keep this website as up-to-date as possible, including links
to other sites that are potentially useful to instructors as well as to students.
The third edition of this book contained a CD-ROM. The material on the
CD-ROM has been expanded significantly; but, in this new edition, this ma-
terial is not included as a CD-ROM. This supplementary electronic material
Springer site

This supplementary electronic material will also be included in the ebook ver-
sion of this text.
A hardcopy of a solutions manual is still available from the author for in-
structors who adopt the book. The solutions provided in the manual have been
prepared by Clifford Stein (Columbia University), Julius Atlason (Michigan),
Jim Geelen (Waterloo), Natalia Shakhlevich (Leeds), Levent Tuncel (Waterloo),
and Martin Savelsbergh (Georgia Tech).
I am very grateful to a number of colleagues and students in academia who
have gone over the new sections and have provided some very useful comments,
namely Stefan Bock (Wuppertal), Banafsheh Khosravi (Southampton), Scott
Mason (Clemson University), Martin Picha, Kirk Pruhs (Pittsburgh), Christian
Rathjen (Wuppertal), Uwe Schwiegelshohn (University Dortmund), Jiri Sgall
(Charles University, Prague), Andrew Wirth (University of Melbourne), and
Lirong Xia (Duke University).
Without the help from various individuals in industry, it would not have been
possible to produce a meaningful chapter on industrial implementations. With
respect to these changes, thanks are due to Oh Ki from Asprova and Gregory
Quinn from Preactor.
The technical production of the book would, again, not have been possible
without the invaluable help from Adam Lewenberg (Stanford University), Achi

Dosanjh (Springer), and Danielle Benzaken (NYU). The continued support of
the National Science Foundation is still very much being appreciated.
Michael Pinedo
Fall 2011
New York
is available for download from the author’s homepage as well as from the



Contents
Preface vii
Supplementary Electronic Material xix
1 Introduction 1
1.1 TheRoleofScheduling 1
1.2 The Scheduling Function in an Enterprise . . . . . . . . . . . . . . . . . . . 4
1.3 OutlineoftheBook 6
Part I Deterministic Models
2 Deterministic Models: Preliminaries 13
2.1 Frameworkand Notation 13
2.2 Examples 20
2.3 ClassesofSchedules 21
2.4 ComplexityHierarchy 26
3 Single Machine Models (Deterministic) 35
3.1 The TotalWeightedCompletionTime 36
3.2 TheMaximumLateness 42
3.3 TheNumberofTardyJobs 47
3.4 TheTotalTardiness-DynamicProgramming 50
3.5 TheTotalTardiness-AnApproximationScheme 54
3.6 TheTotalWeightedTardiness 57
3.7 Discussion 61

4 Advanced Single Machine Models (Deterministic) 69
4.1 TheTotalEarlinessand Tardiness 70
4.2 PrimaryandSecondaryObjectives 77
4.3 MultipleObjectives:AParametricAnalysis 79
xiii

xiv Contents
4.4 The Makespan with Sequence Dependent Setup Times . . . . . . . . 82
4.5 Job Families with Setup Times . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91
4.6 BatchProcessing 98
4.7 Discussion 104
5 Parallel Machine Models (Deterministic) 111
5.1 TheMakespanwithoutPreemptions 112
5.2 TheMakespanwithPreemptions 122
5.3 The Total Completion Time without Preemptions . . . . . . . . . . . . 129
5.4 The Total Completion Time with Preemptions . . . . . . . . . . . . . . . 133
5.5 DueDateRelatedObjectives 136
5.6 OnlineScheduling 137
5.7 Discussion 142
6 Flow Shops and Flexible Flow Shops (Deterministic) 151
6.1 Flow Shops with Unlimited Intermediate Storage . . . . . . . . . . . . . 152
6.2 Flow Shops with Limited Intermediate Storage . . . . . . . . . . . . . . . 161
6.3 Proportionate Flow Shops with Unlimited and Limited
IntermediateStorage 167
6.4 Flexible Flow Shops with Unlimited Intermediate Storage . . . . . 174
6.5 Discussion 176
7 Job Shops (Deterministic) 183
7.1 Disjunctive Programming and Branch-and-Bound . . . . . . . . . . . . 183
7.2 The Shifting Bottleneck Heuristic and the Makespan . . . . . . . . . . 193
7.3 The Shifting Bottleneck Heuristic and the Total Weighted

Tardiness 201
7.4 Constraint Programming and the Makespan . . . . . . . . . . . . . . . . . 207
7.5 Discussion 215
8 Open Shops (Deterministic) 221
8.1 TheMakespanwithoutPreemptions 221
8.2 TheMakespanwithPreemptions 225
8.3 TheMaximumLatenesswithoutPreemptions 228
8.4 The MaximumLateness with Preemptions 233
8.5 TheNumberofTardyJobs 237
8.6 Discussion 238
Part II Stochastic Models
9 Stochastic Models: Preliminaries 247
9.1 Frameworkand Notation 247
9.2 Distributions and Classes of Distributions . . . . . . . . . . . . . . . . . . . 248
9.3 StochasticDominance 252

Contents xv
9.4 Impact ofRandomness onFixedSchedules 255
9.5 ClassesofPolicies 259
10 Single Machine Models (Stochastic) 267
10.1 ArbitraryDistributionswithoutPreemptions 267
10.2 Arbitrary Distributions with Preemptions: the Gittins Index . . . 274
10.3 LikelihoodRatioOrderedDistributions 279
10.4 ExponentialDistributions 282
10.5 Discussion 289
11 Single Machine Models with Release Dates (Stochastic) 295
11.1 Arbitrary Release Dates and Arbitrary Processing Times
withoutPreemptions 296
11.2 Priority Queues, Work Conservation and Poisson Releases . . . . . 298
11.3 Arbitrary Releases and Exponential Processing Times with

Preemptions 302
11.4 Poisson Releases and Arbitrary Processing Times without
Preemptions 308
11.5 Discussion 314
12 Parallel Machine Models (Stochastic) 321
12.1 The Makespan and Total Completion Time without
Preemptions 322
12.2 The Makespan and Total Completion Time with Preemptions . . 331
12.3 DueDateRelatedObjectives 339
12.4 Bounds Obtained through Online Scheduling . . . . . . . . . . . . . . . . . 341
12.5 Discussion 343
13 Flow Shops, Job Shops and Open Shops (Stochastic) 349
13.1 Stochastic Flow Shops with Unlimited Intermediate Storage . . . 350
13.2 StochasticFlowShopswithBlocking 356
13.3 StochasticJobShops 361
13.4 StochasticOpenShops 362
13.5 Discussion 368
Part III Scheduling in Practice
14 General Purpose Procedures for Deterministic Scheduling . . 375
14.1 DispatchingRules 376
14.2 CompositeDispatching Rules 377
14.3 Local Search: Simulated Annealing and Tabu-Search . . . . . . . . . . 382
14.4 LocalSearch:GeneticAlgorithms 389
14.5 Ant ColonyOptimization 391
14.6 Discussion 393

xvi Contents
15 More Advanced General Purpose Procedures 399
15.1 BeamSearch 400
15.2 Decomposition Methods and Rolling Horizon Procedures . . . . . . 402

15.3 ConstraintProgramming 407
15.4 Market-BasedandAgent-BasedProcedures 411
15.5 Procedures for Scheduling Problems with Multiple Objectives . . 418
15.6 Discussion 424
16 Modeling and Solving Scheduling Problems in Practice . . . . . 431
16.1 SchedulingProblemsinPractice 432
16.2 CyclicSchedulingofaFlowLine 435
16.3 Scheduling of a Flexible Flow Line with Limited Buffers and
Bypass 440
16.4 Scheduling of a Flexible Flow Line with Unlimited Buffers and
Setups 445
16.5 Scheduling a Bank of Parallel Machines with Jobs having
ReleaseDatesandDueDates 452
16.6 Discussion 454
17 Design and Implementation of Scheduling Systems: Basic
Concepts 459
17.1 SystemsArchitecture 460
17.2 Databases, Object Bases, and Knowledge-Bases . . . . . . . . . . . . . . 462
17.3 Modulesfor GeneratingSchedules 467
17.4 User Interfaces and Interactive Optimization . . . . . . . . . . . . . . . . . 470
17.5 Generic Systems vs. Application-Specific Systems . . . . . . . . . . . . . 476
17.6 Implementationand Maintenance Issues 479
18 Design and Implementation of Scheduling Systems: More
Advanced Concepts 485
18.1 Robustness and Reactive Decision Making . . . . . . . . . . . . . . . . . . . 486
18.2 MachineLearningMechanisms 491
18.3 Design of Scheduling Engines and Algorithm Libraries . . . . . . . . 496
18.4 ReconfigurableSystems 500
18.5 Web-BasedSchedulingSystems 502
18.6 Discussion 505

19 Examples of System Designs and Implementations 511
19.1 SAP’s Production Planning and Detailed Scheduling System . . . 512
19.2 IBM’sIndependent AgentsArchitecture 516
19.3 Real Time Dispatching and Agent Scheduling at AMD . . . . . . . . 519
19.4 ASPROVAAdvanced PlanningandScheduling 524
19.5 PreactorPlanningandSchedulingSystems 529
19.6 TaylorSchedulingSoftware 534

Contents xvii
19.7 LEKIN-A SystemDeveloped in Academia 539
19.8 Discussion 546
20 What Lies Ahead? 547
20.1 TheoreticalResearch 547
20.2 AppliedResearch 550
20.3 SystemsDevelopment 553
Appendices
A Mathematical Programming: Formulations and Applications 559
A.1 LinearProgrammingFormulations 559
A.2 IntegerProgrammingFormulations 563
A.3 Bounds, Approximations and Heuristics Based on Linear
Programming 567
A.4 DisjunctiveProgrammingFormulations 569
B Deterministic and Stochastic Dynamic Programming 573
B.1 DeterministicDynamicProgramming 573
B.2 StochasticDynamicProgramming 577
C Constraint Programming 581
C.1 ConstraintSatisfaction 581
C.2 ConstraintProgramming 583
C.3 An Example of a Constraint Programming Language . . . . . . . . . . 585
C.4 Constraint Programming vs. Mathematical Programming . . . . . . 586

D Complexity Theory 589
D.1 Preliminaries 589
D.2 PolynomialTimeSolutionsversusNP-Hardness 592
D.3 Examples 595
D.4 ApproximationAlgorithmsandSchemes 598
E Complexity Classification of Deterministic Scheduling
Problems 603
F Overview of Stochastic Scheduling Problems 607
G Selected Scheduling Systems 611
H The Lekin System 615
H.1 Formatting of Input and Output Files . . . . . . . . . . . . . . . . . . . . . . . 615
H.2 LinkingScheduling Programs 617
References 623

xviii Contents
Subject Index 661
Name Index 667

Supplementary Electronic
Material
The supplementary electronic material listed below is available for download
from the author’s homepage as well as from the Springer site

This electronic material is also included in the ebook version of this text.
1. Slides from Academia
(a) University of Michigan, Ann Arbor (Julius Atlason)
(b) Technical University of Twente (Johann Hurink)
(c) State University of New York at Buffalo (Rakesh Nagi)
(d) University of Bonn (Tim Nieberg)
(e) University of Dortmund (Uwe Schwiegelshohn)

(f) University of Leeds (Natalia Shakhlevich)
2. Scheduling Systems
(a) LEKIN (New York University - Michael Pinedo and Andrew Feldman)
(b) LiSA (University of Magdeburg - Heidemarie Braesel)
(c) TORSCHE (Czech Technical University - Michal Kutil)
3. Scheduling Case
(a) Scheduling in the Time-Shared Jet Business (Carnegie-Mellon Univer-
sity - Pinar Keskinocak and Sridhar Tayur)
4. Mini-Cases
(a) Kihara Manufacturing Company (Asprova)
(b) Mitsubishi Electric Corporation – Nakatsugawa Works (Asprova)
(c) Autoparts Manufacturer (Asprova)
(d) Mitsubishi Electric Corporation – Nagoya Plant (Asprova)
(e) Mitusbishi Heavy Industries, Ltd. (Asprova)
(f) Plastform (Preactor)
(g) Teikon (Preactor)
(h) BCM Kosmetik (Taylor Software)
(i) Beaver Plastics (Taylor Software)
xix

xx Supplementary Electronic Material
(j) Fountain Set (Holdings) Limited (Taylor Software)
(k) Lexmark (Taylor Software)
(l) Major Pharmaceuticals Manufacturer (Taylor Software)
(m) Major Printing Supplies Company (Taylor Software)
(n) Grammer (SAP)
(o) Mittal Steel Germany (SAP)
(p) mySAP Supply Chain Management (SAP)
5. Handouts
(a) University of Leeds (Natalia Shakhlevich)

6. Movies
(a) SAIGA - Scheduling at the Paris Airports (ILOG)
(b) Scheduling at United Airlines
(c) Preactor International

Part I
Deterministic Models
2 DeterministicModels:Preliminaries 13
3 Single Machine Models(Deterministic) 35
4 Advanced SingleMachineModels(Deterministic) 69
5 Parallel Machine Models(Deterministic) 111
6 FlowShopsandFlexibleFlowShops(Deterministic) 151
7 JobShops(Deterministic) 183
8 Open Shops (Deterministic) 221

Chapter 2
Deterministic Models:
Preliminaries
2.1 Framework andNotation 13
2.2 Examples 20
2.3 Classes ofSchedules 21
2.4 ComplexityHierarchy 26
Over the last fifty years a considerable amount of research effort has been fo-
cused on deterministic scheduling. The number and variety of models considered
is astounding. During this time a notation has evolved that succinctly captures
the structure of many (but for sure not all) deterministic models that have been
considered in the literature.
The first section in this chapter presents an adapted version of this notation.
The second section contains a number of examples and describes some of the
shortcomings of the framework and notation. The third section describes sev-

eral classes of schedules. A class of schedules is typically characterized by the
freedom the scheduler has in the decision-making process. The last section dis-
cusses the complexity of the scheduling problems introduced in the first section.
This last section can be used, together with Appendixes D and E, to classify
scheduling problems according to their complexity.
2.1 Framework and Notation
In all the scheduling problems considered the number of jobs and the number
of machines are assumed to be finite. The number of jobs is denoted by n and
the number of machines by m. Usually, the subscript j refers to a job while the
subscript i refers to a machine. If a job requires a number of processing steps
or operations, then the pair (i, j) refers to the processing step or operation of
job j on machine i. The following pieces of data are associated with job j.
DOI 10.1007/978-1-4614- , © Springer Science+Business Media, LLC 2012
,
2-
M.L. Pinedo, Scheduling: Theory, Algorithms, and Systems
361 4_2
13

14 2 Deterministic Models: Preliminaries
Processing time (p
ij
)Thep
ij
represents the processing time of job j on
machine i. The subscript i is omitted if the processing time of job j does not
depend on the machine or if job j is only to be processed on one given machine.
Release date (r
j
) The release date r

j
of job j may also be referred to as
the ready date. It is the time the job arrives at the system, i.e., the earliest time
at which job j can start its processing.
Due date (d
j
) The due date d
j
of job j represents the committed shipping or
completion date (i.e., the date the job is promised to the customer). Completion
of a job after its due date is allowed, but then a penalty is incurred. When a
due date must bemetitisreferredtoasadeadline and denoted by
¯
d
j
.
Weight (w
j
)Theweightw
j
of job j is basically a priority factor, denoting
the importance of job j relative to the other jobs in the system. For example,
this weight may represent the actual cost of keeping the job in the system. This
cost could be a holding or inventory cost; it also could represent the amount of
value already added to the job.
A scheduling problem is described by a triplet α | β | γ.Theα field describes
the machine environment and contains just one entry. The β field provides
details of processing characteristics and constraints and may contain no entry
at all, a single entry, or multiple entries. The γ field describes the objective to
be minimized and often contains a single entry.

The possible machine environments specified in the α field are:
Single machine (1) The case of a single machine is the simplest of all pos-
sible machine environments and is a special case of all other more complicated
machine environments.
Identical machines in parallel (Pm)Therearem identical machines in
parallel. Job j requires a single operation and may be processed on any one of
the m machines or on any one that belongs to a given subset. If job j cannot
be processed on just any machine, but only on any one belonging to a specific
subset M
j
, then the entry M
j
appears in the β field.
Machines in parallel with different speeds (Qm)Therearem machines
in parallel with different speeds. The speed of machine i is denoted by v
i
.The
time p
ij
that job j spends on machine i is equal to p
j
/v
i
(assuming job j receives
all its processing from machine i). This environment is referred to as uniform
machines. If all machines have the same speed, i.e., v
i
=1foralli and p
ij
= p

j
,
then the environment is identical to the previous one.
Unrelated machines in parallel (Rm) This environment is a further
generalization of the previous one. There are m different machines in parallel.
Machine i can process job j at speed v
ij
.Thetimep
ij
that job j spends on
machine i is equal to p
j
/v
ij
(again assuming job j receives all its processing
from machine i). If the speeds of the machines are independent of the jobs, i.e.,
v
ij
= v
i
for all i and j, then the environment is identical to the previous one.

2.1 Framework and Notation 15
Flow shop (Fm)Therearem machines in series. Each job has to be
processedoneachoneofthem machines. All jobs have to follow the same
route, i.e., they have to be processed first on machine 1, then on machine 2,
and so on. After completion on one machine a job joins the queue at the next
machine. Usually, all queues are assumed to operate under the First In First
Out (FIFO) discipline, that is, a job cannot ”pass” another while waiting in
a queue. If the FIFO discipline is in effect the flow shop is referred to as a

permutation flow shop and the β field includes the entry prmu.
Flexible flow shop (FFc) A flexible flow shop is a generalization of the flow
shop and the parallel machine environments. Instead of m machines in series
there are c stages in series with at each stage a number of identical machines in
parallel. Each job has to be processed first at stage 1, then at stage 2, and so on.
A stage functions as a bank of parallel machines; at each stage job j requires
processing on only one machine and any machine can do. The queues between
the various stages may or may not operate according to the First Come First
Served (FCFS) discipline. (Flexible flow shops have in the literature at times
also been referred to as hybrid flow shops and as multi-processor flow shops.)
Job shop (Jm) Inajobshopwithm machines each job has its own
predetermined route to follow. A distinction is made between job shops in which
each job visits each machine at most once and job shops in which a job may
visit each machine more than once. In the latter case the β-field contains the
entry rcrc for recirculation.
Flexible job shop (FJc) A flexible job shop is a generalization of the job
shop and the parallel machine environments. Instead of m machines in series
there are c work centers with at each work center a number of identical machines
in parallel. Each job has its own route to follow through the shop; job j requires
processing at each work center on only one machine and any machine can do.
If a job on its route through the shop may visit a work center more than once,
then the β-field contains the entry rcrc for recirculation.
Open shop (Om)Therearem machines. Each job has to be processed
again on each one of the m machines. However, some of these processing times
may be zero. There are no restrictions with regard to the routing of each job
through the machine environment. The scheduler is allowed to determine a
route for each job and different jobs may have different routes.
The processing restrictions and constraints specified in the β field may in-
clude multiple entries. Possible entries in the β field are:
Release dates (r

j
) If this symbol appears in the β field, then job j cannot
start its processing before its release date r
j
.Ifr
j
does not appear in the β
field, the processing of job j may start at any time. In contrast to release dates,
due dates are not specified in this field. The type of objective function gives
sufficient indication whether or not there are due dates.