44 Chapter 2 REVIEW OF LITERATURE, NEED, SCOPE, OBJECTIVES AND RESEARCH METHODOLOGY This chapter deals with the review of the existing literature that was relevant for the subject matter of the thesis. The first step in the research involved the collection of secondary data from all the possible sources that directly or indirectly focused on the main theme of the research study. Accordingly literature scan was undertaken. Efforts were made to prepare the list of relevant material and procure it so that conceptual clarity could be achieved. Secondary data was collected from various publications, journals, magazines, books, newspapers, institutional reports and internet etc. Leading on from that, the literature review seeks to lay a foundation for the current research. The gaps in previous studies were identified to uphold the need of this research. This chapter also deals with the scope, objectives, the methodology followed and limitations of the research. 2.1 REVIEW OF LITERATURE A lot has been written about simulation. A review of literature indicates three important phases of thinking and writing about the subject. The first phase, the time soon after the simulation concept formulation saw accumulation of literature on the concept crystallization and elaboration. Here the basic issue that attracted attention of scholars was to clarify what simulation is and what it is not. Once the consciousness began to emerge over the meaning and concept, the attention of thinkers and scholars shifted to its role in business processes, consequently the second phase of Business Process Simulation arrived. As the idea of Business Process Reengineering (BPR)
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Chapter 2
REVIEW OF LITERATURE, NEED, SCOPE, OBJECTIVES AND RESEARCH METHODOLOGY
This chapter deals with the review of the existing literature that was relevant for the
subject matter of the thesis. The first step in the research involved the collection of
secondary data from all the possible sources that directly or indirectly focused on the
main theme of the research study. Accordingly literature scan was undertaken. Efforts
were made to prepare the list of relevant material and procure it so that conceptual
clarity could be achieved. Secondary data was collected from various publications,
journals, magazines, books, newspapers, institutional reports and internet etc.
Leading on from that, the literature review seeks to lay a foundation for the current
research. The gaps in previous studies were identified to uphold the need of this
research. This chapter also deals with the scope, objectives, the methodology followed
and limitations of the research.
2.1 REVIEW OF LITERATURE
A lot has been written about simulation. A review of literature indicates three
important phases of thinking and writing about the subject. The first phase, the time
soon after the simulation concept formulation saw accumulation of literature on the
concept crystallization and elaboration. Here the basic issue that attracted attention of
scholars was to clarify what simulation is and what it is not. Once the consciousness
began to emerge over the meaning and concept, the attention of thinkers and scholars
shifted to its role in business processes, consequently the second phase of Business
Process Simulation arrived. As the idea of Business Process Reengineering (BPR)
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won appreciation of both business managers and scholars, the concern shifted to the
question as to how it can be adopted and implemented in business, what type of tools
have to be built so as to minimize the risk involved in full scale production. This era also
saw proliferation of simulation tools and thus the user got confused about which tool should be used
and why. Thus in the recent past, scholarly attitude has shifted to evaluation and selection of simulation
tools.
The three main components in the study are - business process simulation, business
process simulation tools and the evaluation & selection of business process simulation
tools, thus the following literature review has been divided into three sub-sections so
that the gap in each subsection may be clearly identified.
2.1.1 Business Process Simulation
The survey of the literature in this domain provides a list of reasons for the
introduction of simulation modelling into business process modelling.
Wild and Otis (1987) described the case of a company that considered the
implementation of 77 new machine tools, for a new production line. However, when
the operation was simulated, they found that 4 machines were actually needed,
presenting a total saving of $750 000. Such savings are not unusual when simulation
is used.
Curtis et al. (1992) suggested that a business process model must be capable of
providing various information elements to its users. Such elements include what
activities comprise the process, who is performing these activities, when and where
are these activities performed, how and why are they executed, and what data
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elements they manipulate. Simulation modelling techniques differ in the extent to
which their constructs highlight the information that answers these questions. To
provide this information, a modelling technique should be capable of representing one
or more of the following modelling perspectives:
§ Functional perspective: Represents what process elements (activities) are
being performed.
§ Behavioural perspective: Represents when activities are performed as well as
aspects of how they are performed through feedback loops, iteration, decision-
making conditions, entry and exit criteria, and so on.
§ Organizational perspective: Represents where and by whom activities are
performed, the physical communication mechanisms used for transfer of
entities, and the physical media and locations used for storing entities.
§ Informational perspective: Represents the informational entities (data)
produced or manipulated by a process and their relationships.
According to Busby and Williams (1993), business process models identify the
structure of the current operations and provide valued information on instituting a self
adjustment mechanism for process improvement. They also indicated that process
models permit process owners and managers to identify inadequate connections
between activities and information systems, duplications of activities, and the creation
of a macro model about cross functional interconnections.
Klein (1994) described the six categories of BPS:
§ Project management e.g. Microsoft Project.
§ Co-ordination, e.g. Microsoft Excel, Lotus Notes, and e-mail.
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§ Modelling, e.g. computer aided software engineering (CASE) tools such as
Popkin System Architect.
§ Analysis, e.g. the same tools as used for modelling.
§ Human resource allocation and design, e.g. assessment, teambuilding and
organization charting (CorelDRAW).
§ Systems development, e.g. Visual C++, and Borland Delphi.
Huckvale and Ould (1995) identified several objectives for which business process
simulation could be employed in a business process reengineering project. They
suggested that business process modelling could provide a means for discussing,
communicating, and analyzing existing processes, an avenue for designing new
processes, a baseline for continuing improvement, and a software program for
controlling processes. They argued that different purposes or objectives of using
processing modelling would require different modelling methods in terms of their
modelling properties and characteristics.
Levas et al. (1995) discussed some of business process modelling issues (such as
problem definition, data collection, socio-political issues, hierarchical and modular
modelling, granularity, integration and multi-perspective issues) needing attention in
BPR projects.
Swain (1995) stressed that simulation can be considered as a vital component in the
enterprise-wide modelling, in which processes once treated as separate functions (e.g.,
manufacturing, sales and design) can be modeled as a group and optimized as a
system.
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Harrel and Field (1996) argued that much of the process definition used in a
simulation model is contained in a process map, yet insufficient data are provided in a
process map for running simulation. Therefore additional information has to be
manually added on the simulation side.
Giaglis and Paul (1996) gave some modelling requirements specific to simulation-
assisted business renovation modelling which are as follows:
§ Processes need to be formally modelled and documented.
§ Modelling should take stochastic nature of business processes into account,
especially the way in which they are triggered by external factors.
§ There is a need to quantitatively evaluate the value of proposed
alternatives.
§ The evaluation is highly dependent on the objectives of the particular study.
§ Modelling tools should be easy to use to allow users of the processes to be
involved in the modelling process.
Greasley and Barlow (1998) identified several areas in business process simulation
projects where simulation modelling can be useful viz. identification of processes for
change, identification of change possibilities, identification of process vision,
understanding of current processes, design and prototyping of new processes.
Fathee et al. (1998) postulated that simulation is the only suitable technique for BPR
as business processes are too complex and confusing because of following reasons:
§ Many business processes are undetermined and include random variables.
§ Activities and resources that are main business process elements have
interactions.
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§ Business processes of organizations affect each other and are changed by
agents outside the organization.
Ackermann et al. (1999) demonstrated that discrete-event simulation can support
five most popular change management approaches. It could be claimed that modelling
provides an important means of discovering the essential aspects of the organizational
system where improvements will make a real difference in performance as well as
providing a sound basis for managing the consequences of the agreed actions.
Muthu et al. (1999) gave a structured approach to business process modelling. They
introduced a consolidated, systematic approach to the redesign of a business
enterprise. The methodology included the five activities i.e. Prepare for reengineering,
Map and analyze As-Is process, Design To-be process, Implement reengineered
process and Improve continuously.
Becker et al. (2000) stressed six principles that are important for business process
modelling: correctness, relevance, economic efficiency, clarity, comparability, and
systematic design. The principle of clarity is extremely subjective and postulates that
the model is understood by the model user. Clarity of models is especially important
when the objective of business process modelling is to facilitate human understanding
and communication or to support process improvement.
According to Irani et al. (2000) the reasons for the introduction of simulation
modelling into process modelling are: simulation allows for the modelling of process
dynamics, the influence of random variables on process development can be
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investigated, re-engineering effects can be anticipated in a quantitative way, process
visualization and animation are provided, and simulation models facilitate
communication between clients and an analyst. The final reason for using simulation
modelling is the fact that it can be increasingly used by those who have little or no
simulation background or experience.
McLean and Leong (2001) pointed that manufacturing simulation will have a major
impact on the way products are manufactured. Due to the high costs of acquisition,
integration, maintenance, limited interoperability, functionality, and performance —
simulation technology is not for everyone yet. Standard interfaces will increase the
functionality and reduce the costs of implementing this new technology. Their
research identified several sets of simulation interfaces that need to be standardized.
Yassine et al. (2001) presented a subjective assessment procedure for rework
probabilities used in project and process management simulation models, in general,
and in the Design Structure Matrix (DSM) simulation model. The assessment
proceeds in three phases: subjective evaluation of task variability and sensitivity,
mapping and calibration, and validation. The application example shows that the
probabilities required for simulating a DSM can be evaluated subjectively.
Furthermore, this assessment method can also be used to shed some light on
evaluating process improvement and reengineering efforts by defining two new
terminologies: reliability and robustness. They said that the goal of restructuring an
iterative process is not to break all iterative loops. Robustness obtained from iterative
task structures can be more valuable than the reliability obtained in a sequential
process structure.
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Lin et al. (2002) suggested that simulation is essential for business process change
projects, enabling two important functions: (1) to capture existing processes by
structurally representing their activities and related elements; and (2) to represent new
processes in order to evaluate their performance. In addition to these functions, a
business process modelling method should enable process evaluation and selection of
alternatives. They stressed that discrete event simulation seems to be an appropriate
method, and it offers a great potential in analyzing business processes.
Hlupic and Vuksic (2004) conducted a case study by engaging business process
modelling techniques. Based on the data presented from the modelling already
undertaken, a reengineered business process was proposed and refined. The effects of
reengineered model were created by performing "what if" analysis. In this phase of
the research a "prototype" of the “TO-BE” model was developed. The improvements
made in the process were evaluated presenting the simulation results to the managers
and end-users. The model was well accepted by both of them and management was
impressed enough to plan to make simulation modelling an integral part of its
business renovation plans.
Mahmudi and Tavakkoli (2004) discussed that there are two kinds of Business
Process Models: analytical (such as flowchart, spreadsheet, data flow diagram,
activity – role diagram, Integrated Computer-Aided Manufacturing and so on) and
simulation. They believed that the core reason for non-success in this area is the use
of analytical models (especially flowcharts and spreadsheets) for redesigning business
processes. To date, many researchers have identified this fact, but there is only a small
body of research to illustrate “why and how “simulation gives better results than
analytical models. They demonstrated by use of a case study that when you use more
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than two criteria for measuring and optimizing the business processes, the results of
analytical model might be non-optimal and even paradoxical.
Further they discussed that analytical tools don’t help analysts in the following areas:
§ Time variable properties of many processes
§ Time based processes (changing the state of system by time)
§ Non-linear relations between elements of processes
§ Randomness property of real processes
§ Unwanted events and occurrence in business environment
Hlupic et al. (2006) discussed the use of simulation for business process modelling
application to business process analysis and re-engineering projects. They argued that
simulation modelling tools are well suited for this purpose and that business
organizations can significantly benefit from a wider application of this approach.
They also argued that design of experiments or suitable search techniques can be
paired with simulation to maximize these benefits and overcome the inherent
limitations of simulation tools. Considering the important role of simulation in
business process modelling, it is critical to promote a wider diffusion of these tools
within the business community.
Popovic et al. (2006) said that process maps have all elements required for business
process simulation and that they have some other benefits, very important for business
process renovation. Business process models built by using process maps technique
can serve as a base for identifying information requirements and planning of
information system development projects. They are also very suitable for the
introduction of a workflow management system. They said that process maps can
serve as a foundation for IS modelling.
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With a simulation tool, we can take a dynamic picture of models. Some researchers
postulate that simulation is the only suitable technique for BPR because business
processes are too complex and confusing:
§ Many business processes are undetermined and include random variables.
§ Activities and resources that are main business process elements have
interactions.
§ Business processes of organizations affect each other and are changed by
agents outside the organization.
The various studies conducted by various researchers at different times on business
process simulation illustrated the advantage of business process simulation in various
areas. Some researchers suggested the capabilities that a business process model
should have. A few studies described the categories of business process simulation
and identified the various objectives for which business process simulation could be
employed. These studies also specified the principles that are important for business
process modelling.
2.1.2 Business Process Simulation Tools
Currently the market offers a variety of discrete-event simulation software packages.
Some are less expensive than others. Some are generic and can be used in a wide
variety of application areas while others are more specific. The following studies
focus on evolution, types and categories of simulation tools in the marketplace.
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Suri and Tomsicek (1990) described rapid modelling tools such as
ManuPlan/SimStarter, marketed by Network Dynamics Inc. The purpose of these
tools is to gain an idea about such measures of performance as throughput and
bottlenecks. The system is modelled in very general terms, omitting many of the
details in order to get an idea about the performance measures. In many instances, this
level of output is sufficient as it answers the questions that are being asked in a timely
manner.
Bhaskar et al. (1994) proposed a set of requirements that should be met by tools used
for modelling and simulation of business processes. These requirements can be
divided into five groups: process documentation, process redesign, performance
measurement, communication, and institutional learning. They have developed
BPMAT software package that can be used throughout a business process
reengineering effort. A major benefit that BPMAT affords through its ease of use is
that re-engineering practitioners can simulate the business process under investigation
and obtain quantitative measurements of key business processes (cost, cycle time,
resource utilization, etc.). This allows the evaluation of alternative process designs in
terms of quantitative criteria and the selection of the most promising ones for
implementation.
Greasley (1994) evaluated a number of tools for the redesign of processes through the
use of two case studies. There is a particular emphasis on the use of Business Process
Simulation in conjunction with Activity Based Costing and Activity Based Budgeting
within the context of a Business Process Reengineering approach. The use of a
balanced scorecard and marking guide can be used to identify suitable processes for
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redesign. A process map enables a study of the relationship between the activities that
form the process. The process map relates to the conceptual map in a simulation
study.
Aalst and Hee (1995) proposed high-level Petri nets as a tool for the modelling and
analysis of business processes. Petri nets have proved to be useful in the context of
logistics and production control. However, the application of these Petri nets is not
restricted to logistics and manufacturing, they can also be used to support business
process reengineering efforts. High-level Petri nets have a formal semantics. A Petri
net model of a business process is a precise and unambiguous description of the
behaviour of the modelled process. The precise nature and the firm mathematical
foundation of Petri nets have resulted in an abundance of analysis methods and tools.
Tumay (1995) gave an overview of business process simulation, described the
modelling and analysis considerations, and listed typical model input, simulation and
output requirements. The study provided a classification of simulation software
products to aid the user in understanding the business process simulation tools and
categorized the business process simulation tools into three categories: flow
diagramming based simulation tools, system dynamics based simulation tools and
discrete event based simulation tools. Further this study presented a simulation
exercise to illustrate the power and suitability of simulation for analyzing a business
process.
Wright and Burns (1996) said that many tools are available to stimulate, simulate
and support the business process modelling approaches, based on different
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methodologies and frameworks. They tended to describe the business process analysis
and modelling market as having three groups:
§ drawing packages with templates;
§ drawing packages with templates and some spreadsheet-like capabilities; and
§ the heavyweight business process analysis tools proper, akin to discrete event
simulators.
Bing and David (1997) examined the wide range of Business Process
Analysis/Modelling (BPA/M) tools available, and compared the features of 12
specific tools. They presented two case studies with examples of software tool
analysis results. The discussion addressed whether these tools met the needs of
managers of change and Business Process Re-engineering (BPR) initiatives, and
offered suggestions for future tool evolution. The focus is to highlight the differences
between the often lofty claims of tool vendors, and both the real needs of BPR
analysts and implementers, and the actual capabilities of the BPR tools.
Kettinger et al. (1997) conducted a survey of existing methodologies, tools, and
techniques for business process change and developed a framework to facilitate
referencing of tools and techniques that help in reengineering strategy, people,
management, and technology dimensions of business processes. Simulation is
mentioned as one of the modelling methods in this survey, and the authors identified a
need for more user-friendly multimedia process capture and simulation software
packages that could allow easy visualization of business processes and enable team
members to actively participate in modelling efforts.
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Law and McComas (1997) classified simulation tools into Languages and
Simulators. Thus, a Simulation Language is a software package that is general in
nature (in terms of the applications it can address) and where model development is
done by programming. The major advantage of a good simulation language is
modelling flexibility, whereas the major disadvantage is that programming expertise
is required. A manufacturing-oriented simulation language is one where the modelling
constructs are specifically oriented toward manufacturing or material handling. The
Manufacturing-oriented Simulator is a simulation package that is designed to model a
manufacturing system in a specific class of systems. This type of software has two
main characteristics: its orientation is toward manufacturing, and little or no
programming is required to build a model (relative to simulation languages).
Aguilar et al. (1999) stated that Business Process Simulation is a powerful tool
supporting analysis and design of business processes. The added value of simulation
is based on four factors:
§ Process performance analysis is improved by simulation-triggered
measurements.
§ Simulation (especially animation) is an effective tool to communicate process thinking and
process analysis results.
§ Simulation enables the migration towards dynamic models for business
processes.
§ Simulation provides essential decision support by anticipating changes.
Stemberger et al. (2003) discussed the level of information system modelling and
simulation modelling methods and tools integration in the conditions of dynamic e-
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business environment. They stressed the necessity for integrating simulation
modelling and information system modelling. The integrated BPM tools combine
formerly diverse areas of business process, IT, resource and financial modelling,
enabling the companies to form a complete view of their operations and providing a
framework for efficient development of robust and complete enterprise architecture.
Vreede et al. (2003) considered the suitability of Arena to simulate business
processes. They stated that a weak point in simulating business processes is the time
consuming and complicated process to create simulation models. They took
advantage of the possibility to develop their own template with predefined building
blocks, which they considered to be successful in several simulation studies they
carried out.
There are large numbers of simulation software available in the market and
researchers have made an attempt to describe many of these business process
modelling tools. Some researches proposed requirements that should be met by
business process simulation tools and based upon this they have divided them into
groups with specific characteristics.
2.1.3 Evaluation & Selection of Business Process Simulation Tools
Evaluation of simulation packages is not new. Many researchers have carried out
surveys on available packages for different purposes. However, there are only a
limited number of papers that describe methods to perform an evaluation and
selection of simulation packages. Some of the studies are:
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One of the best known early simulation software evaluation and comparison was
carried out by Tocher (1965). The simulation languages analyzed were: GPSS,
SIMPAC, SIMSCRIPT, SIMULA, CSL, ESP, GSP, MONTECODE and SIMON.
These languages are examined on the basis of the following groups of criteria: the
organization of time and activities in a simulation programming system, naming and
structure of entities and generalized activity specification, testing of conditions in
activities, test formation facilities, statistics collection procedures. It is estimated how
well the languages under consideration satisfy the criteria within each group.
Subsequently, each language is briefly described with an emphasis on its main
qualities and weaknesses. The languages evaluated have not been ranked nor were
particular ones recommended for use.
A comprehensive evaluation of fifteen simulation languages is provided by Cellier
(1983). Languages examined are ACSL, DARE-P, SIMNON, DYMOLA, SYSMOD,