simulation in the supply chain context: a survey
TRANSCRIPT
Simulation in the supply chain context: a survey
Sergio Terzia,*, Sergio Cavalierib
aPolitecnico di Milano, Department of Economics, Industrial and Management Engineering, Piazza Leonardo da Vinci 32, 20133 Milan, ItalybDepartment of Industrial Engineering, Universita di Bergamo, Viale Marconi 5, 24044 Dalmine, Italy
Received 29 January 2003; accepted 13 June 2003
Abstract
The increased level of competitiveness in all industrial sectors, exacerbated in the last years by the globalisation of the
economies and by the sharp fall of the final demands, are pushing enterprises to strive for a further optimisation of their
organisational processes, and in particular to pursue new forms of collaboration and partnership with their direct logistics
counterparts. As a result, at a company level there is a progressive shift towards an external perspective with the design and
implementation of new management strategies, which are generally named with the term of supply chain management (SCM).
However, despite the flourish of several IT solutions in this context, there are still evident hurdles to overcome, mainly due to
the major complexity of the problems to be tackled in a logistics network and to the conflicts resulting from local objectives
versus network strategies.
Among the techniques supporting a multi-decisional context, as a supply chain (SC) is, simulation can undoubtedly play an
important role, above all for its main property to provide what-if analysis and to evaluate quantitatively benefits and issues deriving
from operating in a co-operative environment rather than playing a pure transaction role with the upstream/downstream tiers.
The paper provides a comprehensive review made on more than 80 articles, with the main purpose of ascertaining which
general objectives simulation is generally called to solve, which paradigms and simulation tools are more suitable, and deriving
useful prescriptions both for practitioners and researchers on its applicability in decision-making processes within the supply
chain context.
# 2003 Elsevier B.V. All rights reserved.
Keywords: Parallel and distributed simulation; Supply chain management; High level architecture; Survey
1. Introduction
Modern industrial enterprises operate in a rapidly
changing world, stressed by even more global com-
petition, managing world-wide procurement and
unforeseeable markets, supervising geographically
distributed production plants, striving for the provi-
sion of outstanding products and high quality custo-
mer service.
More than in the past, companies which are not able
to revise periodically their strategies and, accordingly,
to modify their organisational processes seriously risk
to be pulled out from the competitive edge.
In the 1990s, companies have made huge efforts for
streamlining their internal business processes, identi-
fying and enhancing the core activities pertaining to
the product value chain, and invested massively in new
intra-company information and communication plat-
forms, as data warehouse or ERP systems.
In the last years, globally active companies, as well
as SMEs, are realising that the efficiency of their own
Computers in Industry 53 (2004) 3–16
* Corresponding author. Fax: þ39-02-2399-2700.
E-mail address: [email protected] (S. Terzi).
0166-3615/$ – see front matter # 2003 Elsevier B.V. All rights reserved.
doi:10.1016/S0166-3615(03)00104-0
businesses is heavily dependent on the collaboration
and co-ordination with their suppliers as well as with
their customers [1]. This external perspective is termed
in literature under the broad concept of supply chain
management (SCM), which is concerned with the
strategic approach of dealing with trans-corporate
logistics planning and operation on an integrated basis
[2]. Adopting a SCM strategy means to apply a business
philosophy where more industrial nodes along a logistic
network act together in a collaborative environment,
pursuing common objectives, exchanging continuously
information, but preserving at the same time the orga-
nisational autonomy of each single unit. This business
vision is applied to different industrial processes (e.g.
procurement, logistics, marketing, etc.) and imple-
menting different policies (e.g. continuous replenish-
ment, co-marketing, etc.). Integrated management
frameworks (as the SCOR [3] model) support the
development of collaboration among multiple tiers
through mutually designed planning and execution
processes along the entire supply chain (SC).
From the IT perspective, a new wave of solutions is
arising with the main hype to overcome all the physical,
organisational and informational hurdles which can
seriously jeopardise any co-operation effort. Advanced
planning and scheduling (APS) systems aim to step
over the intra-company integration supplied by ERP
systems by providing a common inter-organisational
SCM platform, which supports the logistics chain along
the whole product life-cycle, from its initial forecast
data, to its planning and scheduling, and finally to its
transportation and distribution to the end customer [4].
Despite the various solutions currently available on the
market, the common features of the APS products
reside on the intensive usage of quantitative methods
in order to provide users with the best solution at time.
An example is given by mixed integer linear program-
ming techniques and genetic algorithms for solving
multi-site or transportation planning problems, or time-
series and regressive techniques for demand planning
problems.
Among these quantitative methods, simulation is
undoubtedly one of the most powerful techniques to
apply, as a decision support system, within a supply
chain environment.
In the industrial area, simulation has been mainly
used for decades as an important support for production
engineers in validating new lay-out choices and correct
sizing of a production plant (e.g. [5,6]). Nowadays,
simulation knowledge is considered one of the most
important competences to acquire and develop within
modern enterprises in different processes (business,
marketing, manufacturing, etc.) [7]. Within the Visions
for 2k-enterprises [8], simulation is considered one of
the most relevant key-success factors for companies
surviving, thanks to its predictable features. Several
organisations consider simulation as an essential deci-
sion support system, for example, since 1996, the USA
Department of Defence (DoD) has been asking to all its
services and parts suppliers to furnish a simulation
model of the product/service provided [9].
In particular, as the topic of the paper, supply chain
is a typical environment where simulation (in parti-
cular, discrete-event simulation) can be considered a
useful device. In fact, it is quite evident to find out
how, by using simulation technology, it is possible to
reproduce and to test different decision-making alter-
natives upon more possible foreseeable scenarios, in
order to ascertain in advance the level of optimality
and robustness of a given strategy.
Aim of the paper is to survey how simulation
techniques (in particular, discrete-event simulation)
could represent one of the main IT enablers in a supply
chain context for creating a collaborative environment
among logistics tiers.
After an introduction to simulation specifications
and terminology (Section 2), a detailed literature
review is proposed (Section 3) in order to analyse
the scope of use, the paradigms employed and the
main benefits reported from the adoption of simulation
techniques in the supply chain context. In Section 4,
final considerations from the authors are provided.
2. The role of simulation techniques in thesupply chain context
Despite the great emphasis given in the last decade
on the need for companies to smooth their physical
boundaries in favour of a more integrated perspective,
there is often among practitioners a lot of confusion
and a flawed use of the term ‘‘integration’’.
Stevens [10] provides a framework for achieving an
integrated supply chain, highlighting that integration
of logistics functions requires a progressive evolution
from intra-company functional integration (i.e. change
4 S. Terzi, S. Cavalieri / Computers in Industry 53 (2004) 3–16
from a functional to a process view of internal activ-
ities) to an internal corporate logistics integration
(supported by ERP, DRP systems), and finally to an
external integration in a logistic network extended
upstream to suppliers and downstream to customers.
The last step is undoubtedly the most challenging
one. However, in addition to the classical morpholo-
gical scheme in corporate logistics, a logistics network
requires, among others, alignment of network strate-
gies and interests, mutual trust and openness among
tiers, high intensity of information sharing, collabora-
tive planning decisions and shared IT tools [1].
These requirements represent often the major hurdles
inhibiting the full integrability of a logistics chain: even
in presence of a strong partnership and mutual trust
among logistics nodes, there are in practice evident
risks of potential conflict areas of local versus global
interests and strong reluctance of sharing common
information related to production planning and sche-
duling as for example inventory and capacity levels.
Hence, from the IT point of view there is the strong
requirement to adopt distributed collaborative solu-
tions, which could preserve at the same time the local
autonomies and privacy of logistics data. Moreover,
these solutions must necessarily be platform indepen-
dent and easily interfaceable with companies’ legacy
systems.
These requirements are profoundly changing also
the traditional paradigms underlying the world of
simulation. In literature, there is a progressive shift
of research and application works from local, single
node simulation studies to modelling of more complex
systems, as logistics channels are.
Generally, simulation of such systems can be car-
ried out according to two structural paradigms: using
only one simulation model, executed over a single
computer (local simulation), or implementing more
models, executed over more calculation processors
(computers and/or multi-processors) in a parallel or
distributed fashion [11].
Consequently, a simulation model of a supply chain
can be designed and realised either traditionally as a
whole single model reproducing all nodes (Fig. 1), or
using more integrated models (one for each node),
which are able to run in parallel mode in a single co-
operating simulation (Fig. 2).
Fig. 1. Local simulation paradigm.
Model
Model Model
Model
Co-operativeSimulation
Fig. 2. Parallel and distributed simulation paradigm.
S. Terzi, S. Cavalieri / Computers in Industry 53 (2004) 3–16 5
The next section will be mainly addressed to the
specification of the parallel and distributed simulation
(PDS) paradigms.
2.1. The parallel and distributed simulation
paradigms
Parallel discrete-event simulation (PS) is concerned
with the execution of simulation programs on multi-
processor computing platforms, while distributed simu-
lation (DS) is concerned with execution of simulations
on geographically distributed computers intercon-
nected via a network, local or wide [11]. Both cases
imply the execution of a single main simulation model,
made up by several sub-simulation models, which are
executed, in a distributed manner, over multiple com-
puting stations. Hence, it is possible to use a single
expression, PDS, referred to both situations.
PDS paradigm is based upon a co-operation and
collaboration concept in which each model co-parti-
cipates to a single simulation execution, as a single
decision-maker of a ‘‘federated’’ environment.
The need of a distributed execution of a simulation
across multiple computers derives from four main
reasons [9,11,12].
� To reduce execution simulation time: A large simu-
lation can be split in more models and so executed
in a shorter time.
� To reproduce a system geographic distribution:
Some systems (as supply chain systems or military
applications) are geographically distributed. There-
fore, reducing them into a single simulation model
is a rough approximation. By preserving the geo-
graphic distribution, the execution of a PDS over
distributed computers enables the creation of virtual
worlds with multiple participants that are physically
located at different sites.
� To integrate different simulation models that
already exist and to integrate different simulation
tools and languages: Simulation models of single
local sub-systems may already exist before
designing a PDS (e.g. flight simulators in military
application, but also local production systems in a
supply chain context) and may be written in
different simulation languages and executed over
different platforms. By using a PDS paradigm, it is
possible to integrate existing models and different
simulation tools into a single environment, with-
out the need to adopt a common platform and
language and to re-write the models.
� To increase tolerance to simulation failures: This is
a potential benefit for particular simulation systems.
Within a PDS, composed by different simulation
processors, if one processor fails, it may be possible
for others processors to go on with simulation runs
without the down processor.
PDS paradigm derives from studies that academic
laboratories and also military agencies have been
realising since 1970. These studies can be classified
according to Fujimoto [11] in two major categories.
� Analytic simulation: This type of simulation is used
to analyse quantitatively the behaviour of systems. In
this case, PDS paradigm is applied to execute as fast
as possible the simulation experimental campaigns.
� Distributed virtual environment: A virtual environ-
ment is composed by more simulation applications
that are used to create a virtual world where humans
can be embedded for training (e.g. soldiers training
in battlefields) and also for entertainment (e.g.
distributed video games) purposes.
In recent years, PDS paradigm has been mainly
used in military applications, but also in several civil
domains (e.g. navy in [13], emergency management in
[14], transportation in [15]).
PDS practical execution needs a framework, which
enables to model the information sharing and synchro-
nicity among single local simulations. In literature, it is
possible to distinguish two different PDS frameworks,
separated by their basic co-ordination logic.
� A network structure, based on a distributed protocol
logic, in which single nodes are mutually intercon-
nected (Fig. 3a).
� A centralised structure, founded on a centric logic,
in which a single process manager is responsible for
linking participant nodes (Fig. 3b).
For the purposes of the paper, it is possible to
synthesise the two frameworks as follows.
� Distributed protocols map interaction messages that
each participant model sends continuously to other
nodes, to bring their update of proper simulation
state. MPI-ASP [16] and GRIDS [17] are examples
of distributed protocols logic.
6 S. Terzi, S. Cavalieri / Computers in Industry 53 (2004) 3–16
� The centric logic provides a software instrument
that is able to receive standard messages from each
connected node, and, therefore, to sort out needed
communications between single participant simula-
tion nodes.
The last logic, as it will be possible to understand
by the following literature survey, is becoming the
most widely used, since it clearly divides connection
and model activity. In fact, in a PDS centric struc-
ture a user is only interested in the model creation,
while the central software solves all connection
problems.
High level architecture (HLA) [12] is the most
known PDS framework. HLA is a standard PDS
architecture developed by the US DoD for military
purposes and nowadays is becoming an IEEE stan-
dard. A PDS in HLA is named ‘‘federation’’ while
participant models are termed ‘‘federates’’. One HLA-
PDS is based on the ‘‘federation and federate rules’’,
which establish 10 ground rules for creating and
managing the simulation. In particular, 10 ‘‘rules’’
identify:
� the HLA interface specification, that defines ser-
vices for federation execution;
� the Object Modelling Template (OMT) language,
for the specification of communications amongst
federates.
Within the HLA framework, a distributed simula-
tion is accomplished through a ‘‘federation’’ of con-
current ‘‘federates’’, interacting between themselves
by means of a shared data model and federation
services (basically time and data distribution manage-
ment services). The federation services are provided
by the Run Time Infrastructure (RTI) software tool,
compliant to the HLA interface specification.
2.2. PDS and supply chain simulation
Many software vendors (e.g. i2 in [18], or IBM in
[19]), universities and consultancy companies have
traditionally used a local simulation approach in the
supply chain context. Only in recent years, some of the
features of PDS were recognised as important benefits
for enabling sound simulation models in support of
SCM policies [20,21].
� PDS ensures the possibilities to realise complex
simulation models which cross the enterprise
boundaries without any need of common sharing
of local production system models and data; as
previously discussed, companies that do not belong
to the same enterprise might not be willing to share
their data openly. Gan et al. [22] explain that PDS
paradigm guarantees the ‘‘encapsulation’’ of differ-
ent local models within one overall complex simu-
lation system, so that, apart from the information
exchanged, each model is self-contained.
� PDS provides a connection between supply chain
nodes that are geographically distributed throughout
the globe, guaranteeing that each single simulation
model is really linked to its respective industrial site.
� In some cases, the execution of a PDS model allows
to reduce the time spent for simulation, since sepa-
rated models run faster than a single complex model.
3. Literature survey
The survey has been conducted over the scientific
literature in order to ascertain which general objec-
tives simulation is generally called to solve, using
which paradigms and simulation tools or languages,
and derive useful prescriptions both for practitioners
and researchers on its applicability in decision-making
processes within the supply chain context.
More than 80 papers have been reviewed. Intro-
ductive papers on supply chain simulation were also
analysed, but they are not classified within the tables.
Reader may note that the survey considers only papers
and references that propose applications of supply
chain simulation, as (i) industrial test cases, or (ii)
simulation software specifically designed for model-
ling supply chains or (iii) simulation tests conducted
over a logistics network.
Fig. 3. PDS frameworks.
S. Terzi, S. Cavalieri / Computers in Industry 53 (2004) 3–16 7
Table 1
Literature survey—local simulation paradigm
Pap
ers
Alf
ieri
and
Bra
nd
imar
te[3
2]
Arc
hib
ald
etal
.[2
8]
Bag
chi
etal
.[1
9]
Bel
hau
etal
.[2
4]
Ber
ryan
dN
aim
[50
]
Bott
eret
al.
[25
]
Burn
ett
and
Le
Bar
on
[51
]
Cav
alie
riet
al.
[52
]
Chen
etal
.[4
0]
Haf
eez
etal
.[5
4]
Hir
sch
etal
.[2
3]
Ing
alls
etal
.[5
5]
Jain
etal
.[5
6]
Lu
oet
al.
[57
]
Mie
lke
[58
]
Per
sso
nan
dO
lhag
er[5
9]
Pet
rov
ic[6
0]
Ph
elp
set
al.
[42
]
Ph
elp
set
al.
[61
]
Pro
mo
del
[27
]
Rit
chie
Du
nh
aman
dA
nd
erso
n[3
7]
Sip
rell
eet
al.
[29]
Sch
un
k[2
6]
Van
der
Vors
tet
al.
[31]
Zh
ang
etal
.[3
0]
Zh
ang
etal
.[3
8]
Scope and objective
Objective
Network design
Design � � � � � � � � � � � � � � � � �Localisation � � � � � � � � �
Strategic decision
Management archetype � � � � � � �Strategic model � � � � � � �
Process
Demand and sales planning � � � � � � � �SC planning � � � � � � � � � �Inventory planning � � � � � � � � � � � � � � �Distribution and
transportation planning
� � � � � � � � � � � � � � � �
Production planning
and scheduling
� � � � � � � � �
Morphology
SC ownership
SC single ownership � � � � � � � � � � � � � � � � � � �SC multi-ownership � � � �
SC levelsa Na 2 Na 2 2þ Na Na 2 Na 2þ Na Na Na 2þ Na Na Na Na Na Na Na Na Na Na 2þ Na
Simulation paradigm and technology
Local � � � � � � � � � � � � � � � � � � � � � � � � � �Specific tool � � � � � � � �General tool � � � � � � � � � � � � � � �
Other (simulation tools
and languages)
Mod
Sim
IBM
SC
A
IBM
SC
A
Cre
ate!
Dy
nam
o
Are
na
Au
tom
od
Jav
a
IBM
SC
A
Dy
nam
o
LO
CO
MO
TIV
E
Are
na
Are
na
Are
na
Are
na
Tay
lor
II
Gen
eral
pu
rpo
se
SD
I
SD
I
SC
Gu
ru
SD
I
Su
pp
lyS
olv
er
Gen
eral
pu
rpo
se
Are
na
Development stageb Ex, Cn Ex Sw Ex, Cn Ex Ex Ex Ex Cn Ex Ex Ex Ex, Cn Ex Ex Ex Ex, Cn Sw Sw Sw Cn Sw Sw Ex, Cn Ex Cn
a Na means information not available.b Cn: conceptual; Sw: software; Ex: experience; Ts: testing.
8S
.Terzi,
S.
Ca
valieri/C
om
pu
tersin
Ind
ustry
53
(20
04
)3
–1
6
Table 2
Literature survey—parallel and distributed simulation paradigm
Papers
Barnett and
Miller [39]
Brun et al.
[35]
Gan et al.
[16]
Gan et al.
[22,33,43]
Gan et al.
[21,44]
Gan and
McGinnis [53]
Kim et al.
[36]
Seliger
et al. [48]
Strasburger et al.
[34,45,46]
Sudra et al.
[17]
Ventateswaran
et al. [62]
Zulch
et al. [63]
Scope and objective
Objective
Network design
Design � � �Localisation
Strategic decision
Management archetype
Strategic model
Process
Demand and sales planning �SC planning � �Inventory planning � �Distribution and transportation planning � � � � �Production planning and scheduling � � �
SC features
SC ownership
SC single ownership
SC multi-ownership � � � � � � � � � �
SC levelsa Na 2 2 2 2 Na Na 2 2 Na 2 Na
Simulation paradigm and technology
PDS � � � � � � � � � � � �Network logic � � �Centric logic � � � � � � � � � � (�)
Other (simulation tools and languages,
PDS frameworks)
HLA HLA (WILD)MPI-HLA DP HLA HLA DEVS/COR-
BA
HLA HLA GRIDS HLA Osim
Development stageb Cn Ts, Ex Ts Ts Ts Ts, Cn Cn Ts Ts Ts Ts Cn
a Na means information not available.b Cn: conceptual; Sw: software; Ex: experience; Ts: testing.
S.
Terzi,S
.C
ava
lieri/Co
mp
uters
inIn
du
stry5
3(2
00
4)
3–
16
9
The survey makes use of a chart classification and its
results are summarised in Tables 1 and 2. Before
detailing the content of the tables, it is necessary to
introduce the classification criteria adopted.
3.1. Classification criteria
Three classification criteria have been adopted for
categorising the reviewed articles.
� Scope and objectives: It is related to the specific
context, the objectives and the scale of the problem
(strategic, tactic, operative) the simulation techni-
que was addressed to.
� Simulation paradigm and technology: It states the
simulation paradigm (e.g. local versus distributed
simulation) and the simulation tools and languages
adopted.
� Development stage: It refers to the different levels
of development of the simulation application
reported in the articles (from the conceptual level
to testing activities or commercial applications).
3.1.1. Scope and objectives
This classification driver is further structured in
three sub-criteria: (1) objectives, (2) processes, (3)
morphology.
(1) Objectives: It is possible to highlight two macro
objectives.
(a) Network SC design: Simulation can be used
as a decision support system within the
design phases (e.g. design of a logistics
network, design of production nodes). Two
sub-levels are defined.
(i) Design: It stands for logical modelling and
industrial nodes configuration. It is possi-
ble to notice that all papers illustrating
specific simulation tools stress this objec-
tive. For example, in Hirsch et al. [23], a
specific supply chain simulation tool,
named LOCOMOTIVE, is adopted to
verify and test more solutions into a
logistic network for packing eco-reusing
and recovery.
(ii) Node localisation: It relates to the
activity of placing a supply chain node
in a determined geographic site. Only a
few simulation models and tools, among
those reviewed, deal with the problem of
geographic disposition of industrial
nodes. For example, in Belhau et al.
[24], a simulation model is conceived in
order to identify the right geographic
disposition for distribution centres, aim-
ing to minimise transport costs through
the use of proper cost functions.
(b) SC strategic decision support: Simulation is
applied over a supply chain to evaluate more
strategic alternatives, as strategies based on
quick response, collaborative planning and
forecasting or outsourcing to third-parties. As
an example, in Botter et al. [25] simulation is
applied on a Brazilian beer logistics network
in order to evaluate the possibility of entirely
outsourcing the logistic process to an external
provider.
(2) Processes: The survey investigates which pro-
cesses are addressed and which decision levels
(strategic, tactic, operative [7]) are pondered in the
simulation applications under scrutiny. The clas-
sification makes use of the same categorisation of
most APS systems [4].
(a) Demand and sales planning: Simulation
processes dealing with stochastic demand
generation (e.g. customer process generation)
and forecasting planning definition.
(b) Supply chain planning: Simulation processes
supporting production planning and distribu-
tion resources allocation, under supply and
capacity constraints; as an example, Schunk
[26] describes a simulation tool, Supply
Solver, which is interfaced with an external
module, which optimises the solution for
distribution and production allocation pro-
blem.
(c) Inventory planning: Simulation processes
supporting multi-inventory planning; the
commercial simulation tool programmed by
Promodel, SCGuru, proposes, a specific
module for inventory management and opti-
misation [27].
(d) Distribution and transportation planning:
Simulation of distribution centres, sites loca-
lisation and transport planning, in terms of
resources, times and costs; it is one of the
most recurrent simulation processes reported
10 S. Terzi, S. Cavalieri / Computers in Industry 53 (2004) 3–16
in literature; for example, as described in
Bagchi et al. [19] and Archibald et al. [28],
IBM supply chain analyser has two separated
modules (distribution and transportation plan-
ning) to simulate distribution centres, trans-
port type (train, truck, etc.) and relative
management processes (material handling,
loading and unloading, etc.).
(e) Production planning and scheduling: Simula-
tion processes related to production manage-
ment. Each logistics node is simulated at its
manufacturing layer, as a specific set of
machines, cells and lines. Manufacturing
planning is implemented by simulation mod-
els (and tools), which integrate different
model layers, from single production lines to
the entire factory and to the whole logistics
chain. SDI Industry Pro [29] is one of the most
important examples of manufacturing plan-
ning implementation; SDI is a simulation tool
specifically developed for logistics chains,
which allows the development of models from
single production machines to more complex
distribution centres.
(3) Morphology: The morphology of the supply
chains addressed by simulation models can be
further refined as follows.
(a) Supply chain ownership: Which distinguishes
two possible conditions.
(i) Single ownership: This is the typical case
of multinational companies, whose in-
dustrial nodes (manufacturers, distribu-
tors, financial sites, etc.) are distributed
all over the world; an example is the case
of IBM and its supply chain analyser [19]
simulation tool specifically developed as
a decision support system for solving
company’s supply chain issues.
(ii) Multi-ownership: In this case, there is a
fair balance of power among more
autonomous enterprises joining a logistics
network. In the LOGSME-ESPRIT 22633
European project, a simulation tool has
been developed in order to support the
decision-making process of a logistics
network made up by SMEs [30].
(b) Supply chain levels: With regards to the
number of tiers along a supply chain, from
the survey, it came out that most of the articles
reviewed do not provide clear information
about the physical dimension of the simulated
systems.
3.1.2. Simulation paradigm and technology
As reported in Section 2.1, there are in literature two
main alternative approaches adopted, with different
choices in terms of tools and languages adopted.
� Local simulation paradigm: With: (i) specific com-
mercial simulation tools developed by software ven-
dors only for simulation purposes within a supply
chain context (e.g. SDI Industry Pro in [29], IBM
SCA in [19], SCGuru in [27], LOCOMOTIVE in
[23], Supply Solver in [26]). (ii) General-purpose
simulation tools or languages, as Arena [25], Create!
[24], CPLEX [31], ModSim [32].
� Parallel and distributed simulation paradigm: With
(i) a network logic approach (e.g. CMB-DIST in
[22], MPI-ASP in [33], GRIDS in [17]); (ii) a
centric logic approach (e.g. HLA in [34,35],
DEVS/CORBA in [36]).
3.1.3. Development stage
From the literature review, it is possible to argue
that the reported simulation studies are at a different
level of development, ranging from as follows.
� Conceptual level: Papers which still denote a con-
ceptual content, since simulation models appear not
yet implemented and tested [36–38], or are mainly
proposals for new descriptive methodologies sup-
porting the adoption of simulation in supply chain
environments [24,31,39,40], or reporting the appli-
cation of novel simulation paradigms, as web-based
simulation [41].
� Software description: Papers which explain features
of tools specifically created for design and devel-
opment of simulation models. Examples of this
category of articles are the two papers presented
at the 1998 and 2000 Winter Simulation Conference
(WSC) by two simulation software development
teams, IBM supply chain analyser [19] and SDI
Industry Pro [42].
� Experience description: Papers which describe real
applications of supply chain simulation. For exam-
ple, Archibald et al. [28] describe a simulation
of a food logistics network aiming to verify the
S. Terzi, S. Cavalieri / Computers in Industry 53 (2004) 3–16 11
effectiveness of alternative logistics management
strategies, in particular, the adoption of continuous
replenishment policies.
� Testing activity: Papers which verify simulation
technology portability in a supply chain context.
In particular, in these papers IT platforms and
software solutions are tested. The stability of dis-
tributed simulation paradigms is the most experi-
mented problem, as it appears by the papers
presented by the research groups of the University
of Singapore [16,21,22,33,43,44] and by the Uni-
versity of Magdeburg [34,45,46].
4. Survey analysis
From the literature survey, it is possible to draw
some useful indications for recognising the future
trends of simulation applications in a supply chain
context.
At first, it is important to notice the clear difference
that exists between local simulation and PDS para-
digms. In fact, after this evidence, authors decided to
divide Tables 1 and 2 in local simulation and PDS
experiences. Next considerations are reported having
in mind this first sharp separation.
4.1. Local simulation paradigm
The local simulation paradigm is still the most
applied approach in literature. It is mainly applied
for supply chain network design, but also for verifying
strategic models and management archetypes. The
most implemented simulation processes are related
to distribution, transportation and inventory planning.
With regards to the simulation tools adopted, with
more powerful simulation tools (e.g. IBM SCA and
SDI), based upon modular construction, it is possible
to describe detailed industry models and more com-
plex supply chain processes; on the other hand, gen-
eral-purpose simulation languages guarantee more
programs flexibility, but with more complexity, so
that they appear not suitable for simulation of
multi-tier logistics networks.
In synthesis, the local simulation paradigm:
� is used in many experiences, with heterogeneous
objectives, from supply chain design to strategic
decisions, within several industrial sectors and with
different company scales;
� is often realised, within the industry environment,
with specific simulation tools, whilst academic
users mostly apply general simulation tools;
� is usually applied to a single-ownership supply
chain (e.g. as in the IBM case), while only for
some experiences is applied to a multi-ownership
supply chain, for the main reason that each com-
pany normally is not willing to share its own
simulation models and data with the other tiers of
the network.
4.2. PDS paradigms
The literature survey on PDS applications points out
clearly that PDS paradigm has not become a steady
applied approach and probably, at this time, the critical
research mass for advancing development and user-
friendly employment has not been yet reached. Cer-
tainly, this is due to the major IT complexity that PDS
paradigm causes.
Among the studies reporting the use of PDS para-
digm, it is worthwhile to report two particular experi-
ences.
� The Web Integrated Logistics Designer (WILD)
project [47], conducted by the authors, which makes
use of heterogeneous simulation models, each
reproducing an industrial node of an aeronautical
multi-ownership logistics chain, written in different
languages and intertwined through the use of the
HLA framework; the main objective of the project
was to integrate the local production planning and
scheduling activities at each node by means of
interaction among distributed simulation models;
in each simulation model, local production systems,
production management and scheduling activities
were simulated.
� The Osim project [48], conducted by the University
of Karlsruhe, which aims to create a hierarchical
simulation where more interconnected simulation
models reproduce different ‘‘industrial’’ processes
and layers (production physical cells, production
management, customers, business control, etc.) in
order to model a single supply chain node. These
coupled models could be (not at the present ver-
sion) interconnected in a more extensive supply
12 S. Terzi, S. Cavalieri / Computers in Industry 53 (2004) 3–16
chain simulation with models of other industrial
nodes.
Both experiences highlight the increasing attention
of the scientific and industrial community for parallel
and distributed supply chain simulation, which is
being developed in different ways:
� in the research world, it is in a testing phase, above
all for solving IT stability problems;
� there is not yet a sufficient critical research mass for
expanding PDS application;
� it is applied mainly to multi-ownership supply
chains, for their main property to solve any infor-
mation-sharing issue among nodes, thanks to the
provision of a common information bus where each
simulation model, even if written with proprietary
language, can be plugged in and synchronised;
� at IT implementation level, it is possible to observe
an evolutionary trend from a network structure,
based on distributed protocols approach, to a centric
structure, especially based on the HLA standard
framework.
5. Conclusions
According to Chang and Makatsoris [49]: ‘‘dis-
crete-event simulation allows the evaluation of oper-
ating performance prior to the implementation of a
system since: (a) it enables companies to perform
powerful what-if analyses leading them to better
planning decisions; (b) it permits the comparison of
various operational alternatives without interrupting
the real system and (c) it permits time compression so
that timely policy decisions can be made’’.
These features are the common background coming
out from the survey reported in this paper, which
shows how simulation is successfully adopted in
different studies related to logistics network.
In particular, the local simulation paradigm is
preferably used within intra-company supply chain
projects (typical of large multinational logistics net-
works) for evaluating and quantitatively ranking dif-
ferent project solutions or for verifying more strategic
policies.
On the contrary, if the supply chain is composed
by independent enterprises, sharing information
becomes a critical obstacle, since each independent
actor typically is not willing to share with the other
nodes its own production data (as production capacity,
internal lead times, production costs, etc.).
This problem is further exacerbated in geographi-
cally distributed networks. Each simulation model of a
local production site of a company needs be locally
resident on each plant. In fact, the maintenance of the
simulation model cannot be carried out centrally, since
only the technical personnel directly working on the
plant is able to maintain and update it whenever the
plant is subjected to any reconfiguration (like instal-
ling new machines or lay-out modifications).
Unlike local simulation, PDS paradigm fulfils
powerfully these requirements. Within the PDS
approach, each simulation model can run in its own
local environment; the data exchange and, above all,
the synchronisation with the other distributed simula-
tion models are ensured by a shared protocol. Thus, in
a supply chain context, collaborating nodes need only
to define at the beginning which information will be
shared and the time steps or the production events
which will trigger the data exchange.
In addition, each model can be developed with
different simulation tools or languages and executed
on heterogeneous platforms, since the establishment of
the shared network is rather similar to a plug-in tool.
This sounds quite important whenever simulation mod-
els already exist: no substantial revisions on the simula-
tion code need to be produced in order to scale it up from
a local running to a distributed experimentation.
PDS can be implemented with the two frameworks
described in Section 2.1, which propose different
solutions for the two most important PDS problems:
(i) data exchanging and (ii) simulation time synchro-
nisation. From literature survey, it is possible to argue
that the centric logic is becoming the most used
framework. In particular, HLA can be considered
the reference, adopted in several simulation projects
within different domains (military, civil, scientific).
This HLA supremacy derives certainly from the
free distribution policy decided by the USA DoD
(developer of the HLA framework), but it also comes
out from evidence: HLA promises a relative simple
approach to PDS and it guarantees all necessary
devices and support.
Once available the proper IT tools, it is possible to
assert that in the future, simulation models developed
with the PDS approach could better enlarge their
S. Terzi, S. Cavalieri / Computers in Industry 53 (2004) 3–16 13
current scope of application as a support to the deci-
sion-making processes of SCM.
Their intensive use will certainly contribute to the
elimination of the current barriers in the accomplish-
ment of a real integration of logistics networks. By
providing a systematic quantitative and objective eva-
luation of the outcomes resulting from different pos-
sible planning scenarios, from demand planning to
transportation and distribution planning, simulation
techniques can make companies more aware of the
benefits coming out from an integrated and co-oper-
ating strategy with their upstream/downstream nodes
rather than following myopically an antagonistic
behaviour with them.
Acknowledgements
The paper reports some of the results achieved by
the authors within the WILD project (refer to its web-
site http://st.itim.unige.it/wild/ for detailed informa-
tion), a project involving seven Italian universities and
funded by the Italian Ministry of Universities
Research & Scientific Technologies. The authors wish
to thank all the collaborating researchers within the
WILD project, in particular, researchers working at
the Dipartimento di Ingegneria Gestionale of Politec-
nico di Milano, namely Prof. Marco Garetti, Prof.
Alessandro Pozzetti, Dr. Alessandro Brun, Dr. Maria
Caridi, Roberto Cigolini and Marco Macchi.
References
[1] R. Hieber, Supply chain management: a collaborative
performance measurement approach, VDF Zurich, 2002.
[2] H.C.W. Lau, W.B. Lee, On a responsive supply chain
information system, International Journal of Physical Dis-
tribution and Logistics Management 30 (7–8) (2000) 598–
610.
[3] SCOR, Supply Chain Operations Reference Model, Supply
Chain Council, 2002 (www.supply-chain.org).
[4] H. Stadtler, C. Kilger, Supply Chain Management and
Advanced Planning, Springer-Verlag, Berlin, 2000.
[5] B. Martinoli, Guida alla simulazione, Franco Angeli Editore,
1993.
[6] R. Brooks, in: S. Robinson (Ed.), Simulation, Operational
Research Series, Palgrave, 2001.
[7] J. Kosturiak, M. Gregor, Simulation in production system life
cycle, Computers in Industry 38 (1999) 159–172.
[8] Integrated Manufacturing Technology Initiative (IMTI),
Modelling and Simulation Roadmap, 2000 (www.imti.net).
[9] Defense Modeling and Simulation Office (DMSO), High
level architecture (HLA) overview, 2002 (hla.dmso.mil).
[10] G. Stevens, Integrating the supply chain, Physical Distribu-
tion & Materials Management 19 (8) (1989) 3–8.
[11] R. Fujimoto, Parallel and distributed simulation, in: Pro-
ceedings of the 1999 Winter Simulation Conference, IEEE,
Piscataway, NJ, pp. 122–131.
[12] Defense Modeling and Simulation Office (DMSO), RTI
Programmer’s Guide, Version NG, 1999 (hla.dmso.mil).
[13] G.A. Bruzzone, R. Mosca, R. Revetria, YACHTS—yet another
cooperative high level architecture training software, in:
Proceedings of the 2001 Winter Simulation Conference, 2001.
[14] U. Klein, Distributed simulation for emergency management
based on the high level architecture, in: Proceedings of the 5th
Conference of the International Emergency Management
Society (TIEMS’98), 1998.
[15] T. Schulze, U. Klein, Migration of HLA into civil domains:
solutions and prototypes for transportation applications,
Simulation 73 (5) (1999) 296–303.
[16] B.P. Gan, L. Liu, J.S. Turner, W. Cai, S. Jain, W.J. Hsu,
Distributed supply chain simulation across enterprise
boundaries, in: Proceedings of the 2000 Winter Simulation
Conference, 2000.
[17] R. Sudra, S.J. Taylor, T. Janahan, Distributed supply chain
simulation in GRIDS, in: Proceedings of the 2000 Winter
Simulation Conference, 2000.
[18] J. Padmos, B. Hubbard, T. Duczmal, S. Saidi, How i2 integrates
simulation in supply chain optimisation, in: Proceedings of the
1999 Winter Simulation Conference, 1999.
[19] S. Bagchi, S. Buckley, M. Ettl, G. Lin, Experience using the
IBM supply chain simulator, in: Proceedings of the 1998
Winter Simulation Conference, 1998.
[20] C. McLean, F. Riddick, The IMS Mission architecture for
distributed manufacturing simulation, in: Proceedings of 2000
Winter Simulation Conference, 2000.
[21] B.P. Gan, W. Cai, S. Turner, Distributed supply-chain
simulation using high level architecture, Transactions of the
Society for Computer Simulation 18 (2) (2001a) 98–109.
[22] B.P. Gan, Y. Low, C. Lim, S. Jain, Bottleneck based
modelling of semiconductor supply chains, in: Proceedings
of the International Conference on Modelling and Analysis of
Semiconductor Manufacturing, 2000.
[23] B.E. Hirsch, T. Kuhlmann, T.J. Schumacher, Logistics simula-
tion of recycling networks, Computer in Industry 24 (1998)
31–38.
[24] T. Belhau, C. Strothotte, D. Ziems, A. Schurholz, M.
Schmitz, Modeling and Simulation of Supply Chain, 1999
(www.uni-magdeburg.de).
[25] R.C. Botter, A. Bergsten Mendes, R. Ferreira de Souza,
Simulation model for the redesign of a supply distribution
system, in: Proceedings of the 1998 Summer Computer
Simulation Conference, 1998.
[26] D. Schunk, Using simulation to analyze supply chain, in:
Proceedings of the 2000 Winter Simulation Conference,
2000.
14 S. Terzi, S. Cavalieri / Computers in Industry 53 (2004) 3–16
[27] Promodel Corporation, Supply Chain Guru, 2002 (www.
promodel.com).
[28] G. Archibald, N. Karabakal, P. Karlsson, Supply chain vs.
supply chain: using simulation to compete beyond the four
walls, in: Proceedings of the 1999 Winter Simulation
Conference, 1999.
[29] A.J. Siprelle, D. Parsons, R.A. Phelps, SDI Industry Pro:
simulation for enterprise wide problem solving, in:
Proceedings of the 1999 Winter Simulation Conference,
1999.
[30] J. Zhang, I. Hunt, C. O’Connor, Simulating and modeling
supply chain activities in the food industry, 1998 (www.cim-
ru.nuigalway.ie).
[31] J.G. Van der Vorst, A.J. Beulens, P. Van Beek, Modelling and
simulating multi-echelon food systems, European Journal of
Operational Research (2000) 354–366.
[32] A. Alfieri, P. Brandimarte, Object-oriented modelling and
simulation of integrated production/distribution systems,
Computer Integrated Manufacturing Systems 10 (1997) 261–
266.
[33] B.P. Gan, Y. Low, C. Lim, S. Jain, W. Cai, W. Hsu, S. Huang,
S. Turner, Parallel discrete-event simulation of a supply chain
in semiconductor industry, in: Proceedings at HPC ASIA,
2000.
[34] S. Strasburger, T. Schulze, M. Schumann, H. Menzler,
Distributed traffic simulation based on the HLA, in:
Proceedings of the 1998 Simulation Interoperability Work-
shop, Fall, 1998.
[35] A. Brun, S. Cavalieri, M. Macchi, A. Portioli-Staudacher, S.
Terzi, Distributed simulation for supply chain co-ordination,
in: Proceedings of the 12th International Working Seminar on
Production Economics, Igls, Austria, 2002.
[36] D. Kim, H. Cao, S. Buckley, Modelling and simulation of
supply chain management based on DEVS and CORBA
framework, in: Proceedings of the 1999 Winter Simulation
Conference, 1999.
[37] J. Ritchie Dunham, E. Anderson, A strategic supply chain
simulation model, in: Proceedings of the 2000 Winter
Simulation Conference, 2000.
[38] J. Zhang, I. Hunt, J. Browne, The development of an
extended enterprise supply chain simulator, 1998 (www.cim-
ru.nuigalway.ie).
[39] M.W. Barnett, C. Miller, Analysis of the virtual enterprise
using distributed supply chain modelling and simulation: an
application of e-SCOR, in: Proceedings of the 2000 Winter
Simulation Conference, 2000.
[40] H.B. Chen, O. Bimber, C. Chatre, E. Poole, S. Buckley,
eSCA: A thin client/server/web-enabled system for distrib-
uted supply chain simulation, in: Proceedings of the 1999
Winter Simulation Conference, 1999.
[41] E.H. Page, S. Griffin, S. Rother, Providing conceptual
framework support for distributed web-based simulation
within the HLA, SPIE, Orlando, 1998, pp. 287–292.
[42] R. Phelps, D.J. Parsons, A. Siprelle, The SDI industry
product suite: simulation from the production line to the
supply chain, in: Proceedings of the 2000 Winter Simulation
Conference, 2000.
[43] B.P. Gan, J. Turner, W. Cai, P. Xavier, Visualization of a
distributed semiconductor supply chain simulation, in:
Proceedings of the 2001 European Simulation Interoperability
Workshop, 2001.
[44] B.P. Gan, J. Turner, W. Cai, Hierarchical Federations: an
architecture for information hiding, PADS USA, 2001.
[45] S. Strasburger, T. Schulze, M. Schumann, E. Bluemel, Using
HLA for factory simulation, in: Proceedings of the 1998 Fall
Simulation Interoperability Workshop, 1998.
[46] S. Strasburger, T. Schulze, U. Klein, Migration of HLA into
civil domains: solutions and prototypes for transportation
applications, Simulation 73 (5) (1999) 296–303.
[47] WILD Consortium, in: A. Bruzzone, R. Mosca, R. Revetria
(Eds.), The Wild Book, University of Genoa, Italy, 2001.
[48] G. Seliger, D. Krutzfeldt, P. Lorenz, S. Strasburger, On the
HLA and Internet-based coupling of commercial simulation
tools for production networks, in: WebSim Symposium,
1999.
[49] Y. Chang, H. Makatsoris, Supply chain modelling using
simulation, International Journal of Simulation 1 (2001).
[50] D. Berry, M. Naim, Quantifying the relative improvements of
redesign strategies in a PC supply chain, International Journal
of Production Economics 46–47 (1996) 181–196.
[51] D. Burnett, T. Le Baron, Efficiently modeling warehouse
systems, in: Proceedings of the 2001 Winter Simulation
Conference, 2001.
[52] S. Cavalieri, V. Cesarotti, S. Grassi, A. Spandri, Coordinated
planning models for managing spare parts inventory in after
sales service, in: Proceedings of the 12th International
Working Seminar on Production Economics, Igls, Austria,
2002.
[53] B.P. Gan, L. McGinnis, Distributed simulation with
incorporated APS procedures for high-fidelity supply chain
optimisation, in: Proceedings of the 2001 Winter Simulation
Conference, 2001.
[54] K. Hafeez, M. Griffiths, J. Griffiths, M. Naim, Systems
design of two-echelon steel industry supply chain, Interna-
tional Journal of Production Economics 45 (1996) 121–130.
[55] R.G. Ingalls, C. Kasales, CSCAT: the Compaq supply chain
analysis tool, in: Proceedings of the 1999 Winter Simulation
Conference, 1999.
[56] S. Jain, L. Collins, R. Workman, E. Ervin, Development of a
high-level supply chain simulation model, in: Proceedings of
the 2001 Winter Simulation Conference, 2001.
[57] Y. Luo, P. Wirojanagud, R. Caudil, Network-based Optimisa-
tion and Simulation of Sustainable e-Supply Chain Manage-
ment, IEEE, Piscataway, NJ, 2001.
[58] R. Mielke, Applications for enterprise simulation, in: Pro-
ceedings of the 1999 Winter Simulation Conference, 1999.
[59] F.J. Persson, D. Olhager, Performance simulation of supply
chain designs, International Journal of Production Economics
77 (2002) 231–245.
[60] D. Petrovic, Simulation of supply chain behaviour and
performance in an uncertain environment, International
Journal of Production Economics 71 (2001) 429–438.
[61] R.A. Phelps, D.J. Parsons, A.J. Siprelle, SDI supply chain
builder: simulation from atoms to the enterprise, in:
S. Terzi, S. Cavalieri / Computers in Industry 53 (2004) 3–16 15
Proceedings of the 2001 Winter Simulation Conference,
2001.
[62] J. Ventateswaran, M. Jafferali, Y. Son, Distributed simula-
tion: an enabling technology for the evaluation of virtual
enterprises, in: Proceedings of the 2001 Winter Simulation
Conference, 2001.
[63] G. Zulch, U. Jonsson, J. Fischer, Hierarchical simulation of
complex production systems by coupling of models,
International Journal of Production Economics 77 (2002)
39–51.
Sergio Terzi is a PhD student of Poli-
tecnico di Milano, Department of Eco-
nomics, Industrial and Management
Engineering, Laboratory of Produc-
tion Systems Design and Management.
He is also taking PhD in conjunction
with CRAN laboratories, University of
Nancy I, France. He received his MSc in
management engineering degrees from
the University of Castellanza in 1999
and from the same university he recei-
ved his BS degrees in economics in 2002. His current research
interests are parallel and distributed simulation applied to industry
and supply chain context, technologies enabling product life-
cycle management within SME and modelling of production
systems.
Sergio Cavalieri is currently associate
professor at the Department of Indus-
trial Engineering of the University of
Bergamo. Graduated in July 1994 in
management and production engineer-
ing, in 1998 he got the PhD title in
management engineering at the Uni-
versity of Padua. His main fields of
interest are modelling and simulation
of manufacturing systems, application
of multi-agent systems and soft-com-
puting techniques (genetic algorithms, ANNs, expert systems)
for operations and supply chain management. He has been
participating to various research projects at national and inter-
national level. He has published two books and about 40 papers
on national and international journals and conference proceed-
ings. He is currently co-ordinator of the IMS Network of Ex-
cellence Special Interest Group on Benchmarking of Production
Scheduling Systems and member of the IFAC-TC on Advanced
Manufacturing Technology.
16 S. Terzi, S. Cavalieri / Computers in Industry 53 (2004) 3–16