Enterprise Modelling IDEF3 David Chen IMS, University Bordeaux 1

IDEF3 - Introduction IDEF3 consists of two models :
Process modelling

=> Diagram of activity flow
Object modelling

=> Diagram of state transition

IDEF3 – Process modelling DEFINITION

A process defines the sequence of execution of a set of activities. It describes activity flow. BASIC ELEMENTS


Unit of Behavior (UOB)




Links




Junctions




Referent




Note

The boxes Unit of Behavior (UOB)

Description of the activity Number of the activity

Verb

1

Reference to IDEF0 if exists

Remark: An UOB represents any concept of process, function, scenario, activity, operation,…

The arrows The arrow represents the links between the boxes. The links can be of different natures: - precedence - relational

Simple precedence links A simple precedence link expresses a temporal link between two units of behaviors Install Electrical outlets

Box 1 (A) is ‘source’

Pain wall

Box 2 (B) is ‘destination’

- A is known as the predecessor (immediate) of B, and B the successor (immediate) of A - Do not precise if ‘A’ can be activated without ‘B’ or ‘B’ can take place without A

Constrained Precedence Links ‘A’ (source) must be followed by ‘B’ (destination) Accept new customer orders

Perform a MRP planning (MRP)

A

B

- Link ‘forced’ (left –> right) - The absence of ‘B’ : inconsistency - The absence of ‘A’ is authorized

Constrained Precedence Links B must be preceded by A

Control quality

Deliver products

A must be followed by B et B must be preceded by A

Heat metal

Mold part

Constrained Precedence Links Precedence Links with particular conditions

Example: B must be activated in 5 minutes after the accomplishment of A

Example The meeting can be closed before the end of the discussion

The committee report must not be discussed before the meeting

The minutes must be distributed after the meeting

Relational links The dashed lines do not have pre-defined meanings. They are used to represent: - constraints defined by users - relational links

Example: The person who ‘sign timesheet’ can not approve his own timesheet

The ‘junction’ boxes Asynchronous

Synchronous

There are three types of junctions : - AND (&) - OR (O) - XOR (X) A junction can be : - converging - diverging

Graphical syntax of junctions Diverging et converging

Junction box AND Junction box : AND Asynchronous

Diverging : Activities B and C must all start after A

Converging : Activities A and B must all end before to start C

Example of junctions AND asynchronous

Temporal diagram

Junction box AND Junction box: AND Synchronous

Diverging: Activities B and C must start simultaneously after A

Converging: Activities A and B must end simultaneously before to start C

Example of junctions AND synchronous

Give the temporal diagram

Junction box OR Junction : OR Asynchronous

Diverging : Either B or C, or both B and C start after A

Converging : Either A or B, or both A and B end before to start C

Example of junctions OR asynchronous

OR

OR

Junction box OR Junction box : OR Synchronous

Diverging : One or more activities (B and C) will start simultaneously after A

Converging : One or more activities (A and B) will end simultaneously

Example: junction OR synchronous

Remark : The fact that J1 and J2 are synchronous will force C and D (case 2) to start and end simultaneously.

Example: junction AND followed by junction OR Can B executed after E ?

Can E start before D is finished ? Extreme case

B after E

E starts without D is finished

XOR junction Junction box: XOR

x

Diverging : Only one activity (B or C) can start

x

Converging : Only one activity (A or B) can end

Decomposition

Number of the Parent box

Number of the decomposition

Reference number of the box (unique)

Example

Decomposition 3.1 of the UOB Receive and Activate Contract

Disconnected UOB It is possible to conceive of UOBs without links to other parts of an IDEF3 schematic Example

Referents Call and Continue Referent : The referenced element needs only to start

before the call element can progress to completion. Call and Wait Referent : The referenced element needs to complete before

the call element can progress to completion..

Call and Wait Referent

Call and Continue Referent Referent type/ label Locator

Referent type - UOB - Scenario - GOTO - etc.

Referent type/ label Locator

Example – Referents Call-and-Continue UDC/D

B can continue after having activated D

9.1.15

A 1

B

C 3

2

Call-and-Wait UDC/D 9.1.15

A 1

B 2

B can only continue after having activated and finished D

C 3

Example – Referent GOTO

A C

D

B

GOTO Activity A

A

1/1

C

D

B

D 4

Note A note box may be attached to a UOB, junction, object, link, or referent.

Notes may be used to provide additional information about a particular IDEF3 model element. Or to attach illustrations, text, screen layouts, comments, etc. to the description.

Example - Note

Examples

Example (1) Use of junction: AND asynchronous

Example (2) Use of junctions: AND synchonous

Example (3) Use of OR and XOR asynchronous junctions

Example (4) Invalid example

IDEF3 - Author / Reader cycle

Understand an IDEF3 diagram

The State transition diagram

Process

State transition

Conclusions
Graphical language for the description of

process => semi formal language
Do not allow representing the use of

resources
The time is not taken into account in IDEF3 model => No simulation
Not executable (=> Workflow)