lecture 6 - ntnu

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Sobah Abbas Petersen

Adjunct Associate [email protected]

TDT4252Modelling of Information Systems

Advanced Course

Lecture 6: Process Modelling TDT4252, Spring 2013

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Overview of lecture today• Process Modelling: IDEF0 and BPMN

Based on the following articles:• 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

Lecture 6: Process Modelling TDT4252, Spring 2013

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From lecture on perspectives to conceptual modelling

• Structural• Functional• Behavioral• Rule-oriented• Object-oriented• Social communication• Actor/role-oriented

Lecture 6: Process Modelling

Perspectives of an enterprise

TDT4252, Spring 2013

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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.

TDT4252, Spring 2013Lecture 6: Process Modelling

Ref: Vernadat, 1996

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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

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Functional Modelling Methods

• Functions can be activities or processes.• Functions are then connected by means of a precedence

relationship to model the business processes of the enterprise.


• 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.

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.

• Task: a part of a set of actions for completion.


Ref: Vernadat, 1996

9 Taxonomy of Manufacturing Enterprise Activities

Design Production Control

ProductionEngineering

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

Production scheduling


Ref: Vernadat, 1996

PlanningScheduling

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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)

• 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)


Goal

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 To-be

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History


• Flow charts• Control flow diagrams• Gantt Charts• Pert charts• SADT/IDEF• UML (Unified Modelling Language)• BPMN (Business Process Modelling

Notation)

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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.

- Not suitable for describing flows (it describes dependencies).

- 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.


Function

Controls

OutputsInputs

Mechanisms

•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

ICOMs

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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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Role of ICOMs

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The ICOMs show their relevance to the processes. They can be considered in more detail as other domains.

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IDEF0 Modelling in Metis• Use MEAF template

• From Model Tree view, select:– Metis Enterprise Architecture Framework

• Process Domain

• Use Modelling Objects:– 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:

– Point to a process or an ICOM

– Click right mouse button, a list of possible relationships appear

– 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

• 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• Comes from manufacturing• Addresses business

environments• Aims to cover O-O,

knowledge representation and software development

UML• 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: 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


lecture 6 - ntnu

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