IDEF3

1
IDEF3

• Process Modeling

2
Importance of Process

• It is not the products, but the processes that
  create products, bring companies long-term
  success.
• Process Ordered sequence of events.
• Business Process Ordered sequence events
  involving people, materials, energy, and
  equipment that is designed to achieve a defined
  business outcome.

3
Motivation for Process Modeling

• Underlying the operations of every
  company--working like its spine-- is its Value
  Delivery System. A companys performance is the
  direct result of how effectively this system is
  structured and managed.
• George Stalk, Jr. Thomas M. Hout
• From BPR Literature

4
What is a Process Model?

• Simply put, the Process Model is the way that
  the work is divided in a value delivery system.
• James B. Swartz
• A representation of a process and its related
  components presented in a time-dependent fashion.
• It also represents the decision logic that exists
  within the system.

5
Benefits of Process Modeling

• Document current processes for standardization.
• Provide guidelines for new process members to
  reduce the learning curve.
• Capture and analyze AS-IS processes.
• Design / redesign process for TO-BE scenarios.
• Test the design of a new process before
  committing to an expensive development project.

6
What is IDEF3?

• The Process Description Capture Method.
• The Object State Transition Description Method.
• Supports descriptions at any desired level of
  detail through Decompositions.
• Employs the concepts of Scenarios to simplify the
  structure of complex process flow descriptions.
• Supports the capture of multiple viewpoints.

7
Flow Charting vs. Process Modeling
8
A Generic Process Modeling Tool ...

• Automates the IDEF3 method.
• Complies with the method standards.
• Provides background quality checking and advisory
  support.
• Utilizes SmartDraw capability.

9
IDEF3 Overview

• Section 1 Basic Elements of the Process
  Diagram
• Section 2 Documenting the Process Flow
• Section 3 Enhancing the Process Description

10
Basic Elements of the Process Diagram

• Processes
• Links
• Junctions

11
Processes
Function Action Process Activity Act Operation E
vent Scenario Decision Procedure
Represented by
Verb-based Label
Node
IDEF Ref
12
Links

• Purpose
• Describe temporal, logical, conventional, or
  natural constraints between processes
• Types of Links
• Simple Precedence
• Object Flow
• Relation

13
Precedence Link

• Express simple temporal precedence between
  instances of one process type and another.
• Each instance of the source process will complete
  before the paired instance of the destination
  process can begin.

You have to turn on the computer before you can
login.
14
Object Flow Link

• Indicates the participation of an object in two
  process instances.
• Has the same temporal semantics as a precedence
  link.
• Lack of an Object Flow link does not preclude the
  existence of an object participation between two
  processes.

There is an object (Part) that is common to both
processes.
15
Relational Link
Commonly used relational (dashed) link
relations Before Meets Starts Triggers
During Overlaps Causes After Finishes Enable
s
(a)
1
1
2
2
16
Junctions

• IDEF3 junctions show convergence or divergence of
  multiple process flows and their timing.

17
Junctions
Asynchronous And All preceding (or following)
actions must complete (or start).
Synchronous And All preceding (or following)
actions must complete (or start) simultaneously.


Asynchronous Or One or more of the preceding
(or following) will complete (or start).
Synchronous Or One or more of the preceding (or
following) will complete (or start)
simultaneously.
O
O
Exclusive Or Exactly one of the preceding (or
following) will complete (or start).
X
18
Junctions Example
Receive purchase requisition
Enter into computer
Fill P.O.
Approve request
Place the order
J7
J8
X J4
15.1
8.1
10.1
7.1
13.1
Assign a P.O.
Deny request
9.1
14.1
Rework purchase request
Goto/Receive purchase requisition
Partially approve
11.1
12.1
7/1
19
Taxonomy of Junctions
20
Junction Semantics
Fan-out (Divergence)
Junction Type
Meaning
All succeeding process paths will eventually
start, and all processes on each path will
eventually happen. All succeeding process paths
will start together, and all processes on each
path will eventually happen. One or more of the
following process paths will eventually start,
and all of the processes on these paths will
happen. There will be a synchronized initiation
of one or more process paths. Exactly one of
the following process paths will be initiated,
and only the processes on that path will happen.

Asynchronous AND
Synchronous AND

Asynchronous OR
O
Synchronous OR
O
XOR
X
21
Junction Semantics
Fan-in (Convergence)
Junction Type
Meaning
Asynchronous AND

All preceding processes must complete. All
preceding processes will complete
simultaneously. One or more of the preceding
processes will complete. One or more of the
preceding processes will complete simultaneously.
Exactly one of the preceding processes will
complete.
Synchronous AND

Asynchronous OR
O
Synchronous OR
O
XOR
X
22
Review
Function Process Activity
Operation Action Event
Process
Verb-based label
Process
IDEF Ref
Junction type
Asynchronous
Junctions
Junction type
Synchronous
Precedence Link Relational Link Object Flow Link
Links
23
Documenting the Process Flow

• Process Elaboration
• Objects
• Referents
• Other Documentation

24
Process Elaboration
25
Elaboration Documentation
Refers To
Elaboration Form
UOB Name
Objects
Facts
Each UOB has an elaboration form that provides
the defining characterization of the real-world
process
Constraints
Description
26
Objects Linked to a Process
Object Types Instances of Object Types

• Entity
• Location
• Resource
• Queue
• Transport

• Paint/Part
• Paint Booth
• Operator
• Part Queue
• Conveyor

27
Referents

• Referents draw the readers attention to an
  important point or note.
• Referents are often used to
• Point to other model elements without showing an
  explicit process flow.
• Indicate a Go-To location in complex process
  flows.
• Specify constraints on junctions.
• Provide links to Object State Transition Networks.

28
Referents
. . . simply point the reader to some other
aspect of the model that needs to be considered.
29
Other Documentation

• Glossary
• Textual descriptions of the process elements.
• Sources
• Source material used in the construction of the
  process description.
• Notes
• Annotations resulting from the model review
  process.

30
Enhancing the Process Descriptions

• Scenario
• Scenario Objectives
• Decompositions
• Object State Transmission Networks

31
Scenarios

• Scenarios are the organizing structure for IDEF3
  descriptions.
• A scenario represents a commonly occurring
  situation.
• Business events that we are specifically planning
  for.
• e.g., core or primary process under
  investigation.
• Different views can be different scenarios.
• A base scenario is always needed.

32
Paint Shop Example
Painting a part in the company paint shop.
33
Scenario Objectives

• Viewpoint
• Determines what can be seen and from what
  perspective.
• Purpose
• Establishes the goal of the communication
  intended by the description.
• Defines why the description is being developed,
  and specifies how it will be used.
• Context
• Establishes the subject of a description.
• Establishes the subject as a part of a larger
  whole.
• Creates a boundary within the environment.

34
Decomposition

• Purpose
• Decreases complexity of a diagram.
• Enables the capture of descriptions at varying
  levels of abstraction.
• Provides the ability to model the same process
  from different knowledge sources or different
  points of view.

Syntactically, a decomposition is just another
IDEF3 process flow diagram.
35
Decomposition
Decompositions allow you to break the process
into pieces which are stand-alone processes.
36
Decomposition

• Types
• Objective view Multiple view decompositions may
  be consolidated into an objective view--the view
  perceived by a neutral observer. There can be
  only one objective view.
• Role view The view of a process as understood
  by, or from the perspective of, one individual,
  role type, or functional organization. There may
  be more than one role view of a process.

37
Purchase Order Example
Top-level Scenario AS-IS Order Process
38
Purchase Order Example
Customer Rec./Dis. Materials
Customer Places Order
Supplier Processes Order
Del. Svc. Transports Materials
2.1
3.1
4.1
1.1
Decomposition Customer Places Order
39
Numbering
Receive purchase requisition
Approve request
X J4
8.1
8
7
Deny request
9
Approve partially
11
Give for approval
Complete proposal
Prepare proposal
Evaluate request
8.1.44
8.1.45
8.1. 46
8.1.47
40
Analyzing Objects Object States

• Objects and their related processes can be
  studied in an object-centered view by using the
  Object State Transition Network (OSTN).

41
The IDEF3 OSTN Language
Object State Label
Object State Transition Arc Referents
Asynchronous Synchronous Referent Referent
42
The IDEF3 OSTN Language
Transition Arcs
Object State
Entry Conditions
State Description
Exit Conditions
In the Object State Elaboration
43
OSTN Diagram
OSTN Referent
Object State II
Scenario Referent
Object State IV
UOB Referent
Object State I
Object State III

• Allows construction of an object-centered view
• Summarizes allowable transitions of an object in
  the domain
• Used to document data life cycles
• Cuts across the process flow diagrams
• Characterizes dynamic behavior of objects

44
Paint Shop Scenario Paint OSTN (Focus Object
Paint)
Paint covered by new layer
Scenario Referent
1
UOB/Test coverage
Solid paint on part
Liquid paint in machine
3
UOB Dry part
Paint covered by polish
2
UOB/Test coverage
3
45
IDEF3 Models

• Reading
• Building

46
Reading IDEF3 Models

• Study the context, purpose, and viewpoint to
  understand the scope of the model.
• Read process flow diagrams from left to right,
  starting with the leftmost process(es).
• Reading a diagram in this manner is called
  performing a walkthrough.
• Examine carefully the description and elaboration
  form of each element.

47
IDEF3 Model Development Process

• Establish and refine CVP - validate
• Collect information and artifacts - validate
• Identify candidate Scenarios - validate
• Identify candidate UOBs - validate
• Specify elaboration per UOB - validate
• Construct process flow diagrams - validate
• Develop OSTN diagram for flow objects - validate
• Refine from OSTN to Flow model - validate
• Apply results - validate
• Maintain

48
Establish and refine CVP

• What are the boundaries
• What is in and out
• Essentially define the top level scenario
• What is visible and what is not
• What are the completion criteria
• What decisions need to be made
• Wont get it right the first time
• Will refine during the course of doing the model

49
Collect Information and Artifacts

• Identify sources and expert reviewers
• Identify stakeholders
• Interview
• All relevant levels in the organization
• Listen carefully
• Take detailed notes
• Collect as much as you can
• Organize the collected material
• Go through the Author-Reader-Review cycle

50
The Author-Reader-Review Cycle

• The team
• source experts
• reviewers
• modelers
• method/modeling experts
• team and project managers
• librarian/model coordinator

Library Coordinator
1.
Kit
Model Author
Expert Reviewer
Kit with Reviewer Comments
2.
Kit with Comments and Author Response
3.
51
Identify candidate objects

• Pick out object references
• Name coining is a key activity
• Definite descriptors need to be converted to
  names
• Use nouns or noun phrases
• Organize the lists
• By kind
• By part-of relations
• Validate with reviewer cycle

52
Group Objects into Hierarchies

• Solidify name references
• Harmonize terminology
• Construct new names for the super-kinds or
  compositions
• May guide modeler in identification of missing
  functions
• Validate with experts

53
Define UOB elaboration

• Associate objects with UOB
• Identify roles that objects play relative to a
  UOB
• flow entity operated upon
• resource objects affects flow entities or each
  other
• information object may be a kind of resource
• Identify facts observed relations between
  objects
• Identify constraints relations that must hold
  for this UOB to occur
• Check object association on the next level of
  detail
• Check object relevance on the same level

54
Construct Diagrams

• Build what diagrams you can from the composition
  relationships
• Look for inconsistent or incomplete statements
• Analyze to find the key missing relations
• Complete the story as best as you can from the
  source material
• Validate with experts

55
Refine upwards and downwards

• Arrange diagrams in hierarchy
• Check consistency of interfaces
• Is the boundary clearly defined?
• Refine upwards
• Do the leaf nodes contain information required to
  address the modeling purpose?
• Refine downwards
• Validate with experts

56
Building IDEF3 Models
Some practical guidelines

• Do not follow an XOR fan-out junction with an AND
  fan-in junction.
• Avoid multiple leftmost processes in a diagram
  their interpretation is ambiguous.
• Use a fan-out junction preceding the multiple
  leftmost processes to clarify the process flow.
• When possible, avoid nested fan-out junctions to
  simplify diagrams.
• A fan-out junction immediately following a fan-in
  junction can indicate a missing process in the
  diagram.

57
Conclusion

• IDEF3 documents current processes for
  standardization and provides guidelines for new
  process members to reduce the learning curve.
• IDEF3 provides a mechanism to capture the
  temporal sequence of a process, the decision
  logic effecting the process, and the state
  transitions of objects within the process.
• IDEF3 serves as a tool to analyze existing
  processes and design and test new processes
  before committing to expensive changes.

58
IDEF0 vs. IDEF3
59
When To Do IDEFØ Before IDEF3

• When definite precedence or flow logic does not
  appear in the description
• When the interviewee tells you what she does, not
  how she does it
• When there are no clear separations between the
  activities being described
• When policy rather than procedure is being
  described

60
When To Do IDEF3 Before IDEFØ

• When the descriptions are very procedural or
  detailed in nature
• Where logical or precedence sequences form a
  major portion of the acquired description
• When the domain expert describes the timing
  and/or logic of a process
• When the domain expert focuses on objects and
  their flow or participation in the environment

61
PROSIM Windows
62
Window Types

• PROSIM provides three window types in which to
  view process models and one for viewing object
  states. Each window provides a different
  perspective on the model.

• Process Flow Nodelist Window
• Process Diagram Window
• Process/Object Matrix Window
• Object State Transition Network (OSTN) Window

63
Process Flow Nodelist Window

• The Process Flow Nodelist Window shows the
  entire hierarchy of scenarios in the active
  project, also indicating the decomposition
  diagrams within each scenario and the processes
  in each diagram.

64
Process Flow Nodelist Window

• Drag and drop elements in the nodelist
• to copy a scenario
• to create a new decomposition
• to move the contents of one diagram to another
• to rearrange processes

65
Process Diagram Window

• The Process Diagram Window shows individual
  models using the standard IDEF3 graphic display.

It provides a process-centered perspective of the
system being modeled.
66
Process/Object Matrix Window

• The P/O Matrix Window shows all the processes in
  the model and all objects associated with those
  processes.

The matrix cells indicate associations between
processes and objects. Cells also show each
objects simulation type.
67
OSTN Window

• The OSTN Window illustrates graphically how
  objects change during a process flow.

68
Presenting the Model
69
Presentation Features

• In Custom Display mode, you can replace elements
  with custom bitmaps and control the color of the
  elements.

External Customer
70
Presentation Features

• In Presentation Display mode, you can drag
  elements into specific Swim Lanes represented by
  different color-codes.

External Customer
71
Importing Exporting Models
72
Model Management

• PROSIMs import and export capabilities allow you
  to exchange and convert between different IDEF
  model types.

• ImportingImport models from other KBSI tools as
  well as text files you create.
• ExportingExport an entire project or a single
  model.

73
Importing Activity Models

• When PROSIM imports activity models, PROSIM
  partially reconstructs the imported models.
  Elements are placed into the pools where you can
  begin distributing them to models in your
  project.

• Activitiesconverted to processes and placed into
  the Process Pool.
• Conceptsconverted to objects and placed into the
  Object Pool.
• Inputs gt Entities
• Outputs gt Entities
• Controls gt Logicals
• Mechanisms gt Resources

74
Exporting

• Entire projects
• Individual diagrams
• Pools
• Simulation models

75
Simulation Modeling in PROSIM
76
What is Simulation?

• Process models represent process-centered views
  of the modeled system and incorporate logical
  assumptions about how the system works.
• In simulation models, this process-centered view
  becomes an object-centered view, allowing the
  modeler to numerically evaluate the performance
  of the model at discrete points of time.

77
Processes Simulation

• Process times and resource rules are a function
  of processes and determine the amount of time
  required for a process to complete and how
  resources are used in a single activation. These
  data map to WITNESS as cycle time and labor.

You can also define the cost of resources and
entity changes that occur in the process.
78
Objects Simulation

• Simulation information for objects represents how
  the object participates in the process.

• For entities, you can define
• How the entity arrives in the process
• The number of entities arriving
• The inter-arrival time of entity batches

79
Junctions Simulation
Simulation information for junctions represents
how junctions produce or combine entities (AND
junctions) or how junctions route entities
through the process flow (XOR junctions).

• For XOR junctions, you can define how the
  junction logically passes entities to the next
  element in the process flow. When you select a
  logic type, you can then detail the type for the
  junction occurrence.

80
Exporting a PROSIM Simulation Model into WITNESS

• STEPS
• Complete validation of PROSIM Simulation Model.
• Generate Simulation Model Code.
• Remember where you saved your file.
• Access Simulation Model File through the WITNESS
  Read Commands option under the File Menu.

81
Running a Simulation Model

• Several options are available for
• running a Simulation Model
• (1) Click on Run and again on Run to run
  the Simulation Model. There are other options
  available for stopping the model (Stop) and for
  returning the model to the start point (Begin).
  You can also use the ICONs at the bottom left
  portion of the WITNESS Screen.
• (2) Click on this ICON to run the Simulation
  Model.
• (3) Click on this ICON to stop the Simulation
  Model.
• (4) Click on this ICON to rewind the model
  (return it to the start point).

82
Process Modeling to Project Planning
83
PROSIM PROJECTLINK
PROJECTLINK allows you to translate your process
models into a scheduling chart format and to
create process models from existing schedules.
Export a .txt file from PROSIM
Import an .mpx file into your project management
software
Save your work in an .mpx format
Import a .txt file into PROSIM
84
Assignment 2

• Develop a IDEF3 process model of a system of your
  choice.
• Make sure to
• Define Context, Purpose, and Viewpoint
• Include at least 2 Levels of Decompositions
• Use at least two different types of junctions
  (XOR, OR, AND)
• Use at least two referents
• Use ProSim to generate and print the diagrams. If
  you wish, you may also use other drawing tools
  (Visio, PowerPoint drawing tools, etc.)
• Assignments should be typed, and should have a
  cover page including your name, date, and
  assignment number.