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TDT4252
Modelling of Information Systems
Advanced Course
Sobah Abbas Petersen
Adjunct Associate Professor
[email protected]
Lecture 7: Process Modelling
TDT4252, Spring 2011
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Overview of lecture today
• Process Modelling: IDEF0 and BPMN
Based on the following article:
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Vernadat, F. B. (1996), Chapter 4: Modelling Functional Aspects, in
Enterprise Modelling and Integration: Principles and Applications.
Chapman and Hall. ISBN: 0 412 60550 3
Noran, Ovidiu, S. Business Modelling: UML vs. IDEF, Griffiths
University, http://www.ict.griffith.edu.au/noran/Docs/UMLvsIDEF.pdf.
Menzel, Christopher, Mayer, Richard J. The IDEF Family of
Languages. (pages 1-11 only) http://cmenzel.org/Papers/idef-family.pdf
A07: Stephen A. White, Introduction to BPMN, BPTrends, July 2004.
http://www.tweetcube.com/uploads/9e0c00e0c1.pdf
Lecture 7: Process Modelling
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From lecture on perspectives to conceptual
modelling
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Structural
Functional
Behavioral
Rule-oriented
Object-oriented
Social communication
Actor/role-oriented
Lecture 7: Process Modelling
Perspectives of
an enterprise
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Functional Modelling
• Methods to model the functional aspects of an
enterprise: the things to be done and the way things are
done in an enterprise.
• The purpose of a functional modelling approach is to
describe the enterprise functionality and enterprise
behaviour to the level of detail required by business
users.
Ref: Vernadat, 1996
Lecture 7: Process Modelling
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Enterprise Functionality
• Concerns the things to be done, i.e. activities and
operations performed, either by humans or machines,
within an enterprise.
• Enterprise functionality represents actions performed in
the form of functions transforming input into output, over
a period of time.
Ref: Vernadat, 1996
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Enterprise Behaviour
• Concerns flow of control within an enterprise, i.e. the
sequence in which things are done.
• Enterprise behaviour governs the way enterprise
functionality is performed according to occurrences of
enterprise states and real-world events.
Ref: Vernadat, 1996
Lecture 7: Process Modelling
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Functional Modelling Methods
• Most functional modelling methods are based on a functional
decomposition principle: functions of the system modelled are
decomposed into sub-functions, sub-functions into sub-functions,
and so on.
• Functions can be activities or processes.
• Functions are then connected by means of a precedence
relationship to model the business processes of the enterprise.
Ref: Vernadat, 1996
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Terminology: Activity and Process
• Activity: An activity f performs something, usually
transforming its inputs into outputs. Generally, this
transformation may happen if some condition C is
verified.
– Activity f transforms an input state into an output state, under condition
C.
• Process: Processes are logico-temporal sequences of
activities. They are partially ordered sets of activities.
Ref: Vernadat, 1996
• Task: a part of a set of actions for completion.
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TDT4252, Spring 2011
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Taxonomy of Manufacturing Enterprise
Activities
Design
Production
Control
Production
Engineering
Manufacturing
Production
Planning
Preliminary
design
Inventory control
Process planning
Machining and
assembly
activities
Long-term
forecasting
Detailed design
Master production
scheduling
Manufacturing
plant layout
design
Process control
Master production
scheduling
Engineering
design/ analysis
Material
requirements
planning
Part programming
Quality control
Material
requirements
planning
Documentation
Production
scheduling
Tool and fixture
design
Planning
Production
scheduling
Scheduling
Ref: Vernadat, 1996
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Business Processes
• A business process is a collection of related,
structured activities or tasks that produce a
specific service or product (serve a particular
goal) for a particular customer or customers.
(Ref: Wikipedia)
Goal
• A business process is a sequence (or partially
ordered set) of enterprise activities, execution of
which is triggered by some event and will result in
some observable or quantifiable result. (Ref:
Vernadat, 1996)
Think as processes instead of functions and procedures!
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Business Processes Modelling
• Business Process Models take into account the
business goals, business structure and the resources
that are available to achieve the business goals.
• This introduces additional concepts to the ones
introduced in functional modelling: input transformed
into output, under a specific condition.
 Business Goals
 Resources
As-is
Lecture 7: Process Modelling
To-be
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History
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Flow charts
Control flow diagrams
Gantt Charts
Pert charts
SADT/IDEF
UML (Unified Modelling Language)
BPMN (Business Process Modelling
Notation)
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TDT4252, Spring 2011
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SADT
• SADT: Structured Analysis Design Technique (Ross 1977, Ross
and Schoman 1977)
• Originally developed as a “system-blueprinting” method for software
engineering, i.e. a method for detailed requirements definition.
• Main strength: it is based on a structured methodology for
decomposing complex systems into functions and sub-functions.
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Not suitable for describing flows (it describes dependencies).
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Only provides a static snapshot of the state of the system.
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IDEF Languages (1)
• ICAM (Integrated Computer Aided Manufacturing)
• IDEF = ICAM DEFinition Language
• Originated in the 1970s, in the US Air Force and the
ICAM program, based on SADT.
• Initially intended for use in Systems Engineering
• IDEF0 : for activity modelling or functional modelling.
• Later a suite of languages: IDEF1, IDEF2… for more
advanced modelling.
• We will focus on IDEF0!
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IDEF0
• IDEF0 : for activity modelling or functional modelling.
• Models the decisions, actions and activities of an
organisation or system, in order to communicate the
functional perspective of a system.
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IDEF0: Syntax
• A model of a function at the highest level of inputs,
outputs, controls and mechanisms.
ICOMs
Controls
Inputs
Function
Mechanisms
Lecture 7: Process Modelling
Outputs
•Inputs: items that trigger or are
transformed in the activity
•Controls: guide or regulate the
activity
•Mechanisms: resources used to
perform the activity
•Outputs: results of the activity or
items processed or transformed
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IDEF0: Decomposition
• The top level is called a context.
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IDEF0: ICOMs
• Input:
– Can be a trigger
– Input that is transformed to output.
• Control
– Guide or regulate activity
– !!! Distinction between input and control: inputs change, controls remain
unchaged.
• Mechanism: resources needed to perform activity
– People
– Equipment, IT
– Financial resources
• Outputs
– Results of a performing the activity
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IDEF0: Dependency & Flow
• Dependency: One process depends on another.
• Flow: something flows between processes: Information,
material
Remember the
Barings Bank
case?
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IDEF0 Model in Metis (1)
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IDEF0 Model in Metis (2)
Role of ICOMs
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IDEF0 Model in Metis (3)
The ICOMs show their
relevance to the
processes. They can be
considered in more detail
as other domains.
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IDEF0 Model in Metis (4)
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IDEF0 Modelling in Metis
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Use MEAF template
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From Model Tree view, select:
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Metis Enterprise Architecture Framework
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Use Modelling Objects:
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Process Domain
Process (object), Process Input (interface), Process Control(interface),
Process Output (interface), Process Mechanism (interface)
To link processes via the ICOMs, use the menu
process modelling menu, available on the process
and ICOM objects:
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Point to a process or an ICOM
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Click right mouse button, a list of possible relationships appear
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Select appropriate relationship
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Connecting IDEF0 ICOMs to Other
Domains in Metis
To link ICOMs to other
domains in the model :
•Select the desired object (e.g. a
document)
•Point to an ICOM
•Click right mouse button, a list of
possible relationships appear
•Select appropriate relationship
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IDEF0: Benefits
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Supports understanding of the organisation
Helps improve our knowledge about the organisation
Supports decision making
Supports planning and improvement (e.g. by adding
new processes easily)
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IDEF0: Strengths & Weaknesses
• Strenghts:
– Effective in detailing the system activities for function modelling.
– Provide a concise description of systems, by using the ICOMs (Input,
Control, Mechanism, Mechanism)
– The hierarchical nature allows the system to be easily refined into
greater detail.
• Weaknesses:
– Can be so concise that only domain experts can understand.
– Can be misinterpreted as representing a sequence of activities.
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IDEF and UML
IDEF
UML
• Comes from manufacturing
• Addresses business
environments
• Aims to cover O-O,
knowledge representation
and software development
• O-O software
• Driven by software
development
• Focussed on designing
software systems
• UML “business
customisations” are based
upon principles borrowed from
IDEF.
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Discussion: IDEF0
• Is IDEF0 functional modelling or Process Modelling or
both?
• How can you use IDEF0 in your assignment?
• How does IDEF0 link to the other modelling methods
and languages we have looked at?
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BPMN: Introduction
• BPMN: Business Process Modelling Notation
• First specification released in May 2004.
• Defines a Business Process Diagram (BPD), which is
based on a flowcharting technique tailored for creating
graphical models of business operations.
• Business Process Model: a network of graphical
objects, which are activities, and the flow controls that
define their order of performance.
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BPMN: Aim
• To create a simple mechanism for creating business
process models, while at the same time being able to
handle the complexity inherent to business processes.
– Simple: use familiar notation
• Categories of Notations
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Flow Objects
Connecting Objects
Swimlanes
Artifacts
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BPMN: Flow Objects
• Set of core elements
• Event: “something” that happens during the
course of a business process.
– Denoted by circles
– Affect the flow of the process: e.g. a trigger or a result.
• Activity: Generic term for work that is
performed.
– Can be atomic (task and sub-processes) or non-atomic
(compound).
• Gateway:
– Used to control the convergence and divergence of
sequence flow: decisions and forking.
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BPMN: Connecting Objects
• Flow objects are connected together in a
diagram to create a basic skeletal structure of a
business process.
• Sequence flow: shows the order or sequence
that activities will be performed in a process.
• Message Flow: shows the flow of messages
between two separate process participants.
• Association: associates data, text and other
artifacts with flow objects. Shows the inputs
and outputs of activities.
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Example: Discussion
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BPMN: Swimlanes
Lecture 7: Process Modelling
TDT4252, Spring 2011
Name
• Lane: A sub-partition within a pool and
will extend the entire length of the pool.
Name
• Pool: A participant in a process.
Name
– A graphical container for a participant’s activities.
Name
• A mechanism to organise activities into
separate visual categories in order to
illustrate different functional capabilities
or responsibilities.
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BPMN: Artifacts
• Allows some flexibility in extending the basic
notation.
• Data object: a mechanism to show how data is
required or produces by activities. They are
connected through associations.
• Group: Can be used for documentation or
analysis purposes, but does affect the sequence
flow.
• Annotation: mechanism for a modeller to
provide additional text in the model.
Lecture 7: Process Modelling
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Text…
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Example: Discussion
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BPMN: General Uses
• Collaboration, B2B (Business to Business)
– When there is a collaboration between two or more organisational
entities.
– Swimlanes are used for this.
– Shows clear resposibilities.
• Internal purposes
– Detailed business process models: flow, sequences, decisions, events,
etc.
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BPMN: Strenghts & Weaknesses
• Strenghts:
– Connects business process representations with system design
– Represents a more unified modelling language than some of its
predecessors
• Weaknesses:
– Difficult to model teamwork where the line of responsibility is not so
clear.
– Focussed towards process execution.
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Discussion: BPMN
• How does BPMN compare to IDEF0?
• How does BPMN link to the other modelling methods
and languages we have looked at?
• How can you use BPMN in your assignment?
When should we use which method?
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Next Lecture
• Product Modelling
– Product Modelling in Metis
• Friday, 25 February 2011, room F4
• There will be an opportunity to talk about the assignment.
Lecture 7: Process Modelling
TDT4252, Spring 2011