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IDEF3. Process Modeling. Importance of Process. It is not the products, but the processes that create products, bring companies long-term success. Process : Ordered sequence of events.

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idef3

IDEF3

Process Modeling

importance of process
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.

MSIS 5653 - Advanced Systems Development

motivation for process modeling
Motivation for Process Modeling

“Underlying the operations of every company--working like its spine-- is its Value Delivery System. A company’s performance is the direct result of how effectively this system is structured and managed.”

— George Stalk, Jr. & Thomas M. Hout

From BPR Literature

MSIS 5653 - Advanced Systems Development

what is a process model
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.

MSIS 5653 - Advanced Systems Development

benefits of process modeling
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.

MSIS 5653 - Advanced Systems Development

what is idef3
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.

MSIS 5653 - Advanced Systems Development

flow charting vs process modeling
Flow Charting

Process Modeling

Conveys process logic in an ambiguous manner

Conveys process logic with unambiguous syntax

Varying levels of abstraction cannot be captured

Can capture varying levels of abstraction from multiple viewpoints

Embellishes the process with objects and simulation data

Does not provide information about the objects in a process

Flow Charting vs. Process Modeling

MSIS 5653 - Advanced Systems Development

a generic process modeling tool
A Generic Process Modeling Tool ...
  • Automates the IDEF3 method.
  • Complies with the method standards.
  • Provides background quality checking and advisory support.
  • Utilizes SmartDraw capability.

MSIS 5653 - Advanced Systems Development

idef3 overview
IDEF3 Overview
  • Section 1: Basic Elements of the Process Diagram
  • Section 2: Documenting the Process Flow
  • Section 3: Enhancing the Process Description

MSIS 5653 - Advanced Systems Development

processes
Processes

Function Action Process

Activity Act Operation

Event Scenario Decision

Procedure

Represented by

Verb-based Label

Node #

IDEF Ref #

MSIS 5653 - Advanced Systems Development

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

MSIS 5653 - Advanced Systems Development

precedence link
Turn on

computer

Login

1

2

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.

MSIS 5653 - Advanced Systems Development

object flow link
Paint Part

Dry Part

1

2

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.

MSIS 5653 - Advanced Systems Development

relational link
Activity B

Activity A

2

1

Relational Link

Commonly used relational (dashed) link relations:

Before Meets Starts Triggers

During Overlaps Causes

After Finishes Enables

(a)

1

1

2

2

MSIS 5653 - Advanced Systems Development

junctions
Fan-out junction

Fan-in junction

2

4

6

1

J2

J1

3

5

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

MSIS 5653 - Advanced Systems Development

junctions17
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

MSIS 5653 - Advanced Systems Development

slide18
Junctions Example

Receive

purchase

requisition

Fill P.O.

Enter into

computer

Place the

order

Approve

request

&

J8

&

J7

X

J4

15.1

8.1

10.1

7.1

13.1

Assign a

P.O.#

Deny

request

14.1

9.1

Goto/Receive

purchase

requisition

Rework

purchase

request

Partially

approve

12.1

11.1

7/1

MSIS 5653 - Advanced Systems Development

taxonomy of junctions
Junctions

Fan-in

Fan-out

XOR (X)

AND (&)

OR (O)

X

Asynchronous

Synchronous

&

&

O

O

Taxonomy of Junctions

MSIS 5653 - Advanced Systems Development

junction semantics
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

MSIS 5653 - Advanced Systems Development

junction semantics21
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

MSIS 5653 - Advanced Systems Development

review
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

MSIS 5653 - Advanced Systems Development

documenting the process flow

Documenting the Process Flow

Process Elaboration

Objects

Referents

Other Documentation

process elaboration
Process Label

Process #

Elaboration Form

Process Label:

Process Reference Number:

Objects:

Facts:

Constraints:

Description:

Process Elaboration

MSIS 5653 - Advanced Systems Development

elaboration documentation
Elaboration Documentation

Refers To

ElaborationForm

UOB Name

Objects

Facts

Each UOB has an elaboration form that provides the defining characterization of the real-world process

Constraints

Description

MSIS 5653 - Advanced Systems Development

objects linked to a process
Paint PartObjects Linked to a Process

Object Types Instances of Object Types

  • Entity
  • Location
  • Resource
  • Queue
  • Transport
  • Paint/Part
  • Paint Booth
  • Operator
  • Part Queue
  • Conveyor

MSIS 5653 - Advanced Systems Development

referents
Referents
  • Referents draw the reader’s 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.

MSIS 5653 - Advanced Systems Development

referents28
Object:

Pur. Req.

Identify Supplier

Negotiate price with vendor

2

3

Receive request for purchase

Prepare and dispatch purchase order

&

&

1

5

J2

J1

Receive request for purchase

4

Scenario /

Ordering Contracted parts

Object /

Contracted Parts

Referents

. . . simply point the reader to some other aspect of the model that needs to be considered.

MSIS 5653 - Advanced Systems Development

other documentation
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.

MSIS 5653 - Advanced Systems Development

enhancing the process descriptions

Enhancing the Process Descriptions

Scenario

Scenario Objectives

Decompositions

Object State Transmission Networks

scenarios
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.

MSIS 5653 - Advanced Systems Development

paint shop example
Go-To/

Paint part

1/1

Paint

part

Dry

part

Test

coverage

X

2

3

1

Route to

next stop

4

Paint Shop Example

“Painting a part in the company paint shop.”

MSIS 5653 - Advanced Systems Development

scenario objectives
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.

MSIS 5653 - Advanced Systems Development

decomposition
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.

MSIS 5653 - Advanced Systems Development

decomposition35
Decomposition

Decompositions allow you to break the process into pieces which are stand-alone processes.

MSIS 5653 - Advanced Systems Development

decomposition36
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.

MSIS 5653 - Advanced Systems Development

purchase order example
Customer Rec./Dis. Materials

Supplier Processes Order

Del. Svc. Transports Materials

Customer Places Order

4.1

2.1

3.1

1.1

Purchase Order Example

Top-level Scenario:

AS-IS Order Process

MSIS 5653 - Advanced Systems Development

purchase order example38
System Generates Pick Ticket File

Open Channel/Send File to Target Printer

Sys. Cross Ref. Part # w/Order Details

Operator Enters Item Description

8.1

6.1

7.1

5.1

Purchase Order Example

Customer Rec./Dis. Materials

Supplier Processes Order

Del. Svc. Transports Materials

Customer Places Order

4.1

2.1

3.1

1.1

Decomposition:

Customer Places Order

MSIS 5653 - Advanced Systems Development

slide39
Numbering

Receive

purchase

requisition

Approve

request

X

J4

8

8.1

7

Deny

request

9

Approve

partially

11

Give for

approval

Prepare

proposal

Complete

proposal

Evaluate

request

8.1.44

8.1.45

8.1. 46

8.1.47

MSIS 5653 - Advanced Systems Development

analyzing objects object states
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).

MSIS 5653 - Advanced Systems Development

the idef3 ostn language
Referent

Type/ID

Referent

Type/ID

Locator

Locator

The IDEF3 OSTN Language

Object

State

Label

Object State

Transition Arc

Referents

Asynchronous Synchronous

Referent Referent

MSIS 5653 - Advanced Systems Development

the idef3 ostn language42
The IDEF3 OSTN Language

Transition Arcs

Object State

Entry

Conditions

State

Description

Exit

Conditions

In the Object

State Elaboration

MSIS 5653 - Advanced Systems Development

ostn diagram
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

MSIS 5653 - Advanced Systems Development

slide44
Paint Shop Scenario: Paint OSTN

(Focus Object: Paint)

Paint

covered by

new layer

Scenario

Referent

1

UOB/Test

coverage

Liquid

paint in

machine

Solid

paint on

part

3

UOB

Dry part

Paint

covered by

polish

2

UOB/Test

coverage

3

MSIS 5653 - Advanced Systems Development

idef3 models

IDEF3 Models

Reading

Building

reading idef3 models
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.

MSIS 5653 - Advanced Systems Development

idef3 model development process
IDEF3 Model Development Process
  • Establish and refine CV&P - 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

MSIS 5653 - Advanced Systems Development

establish and refine cv p
Establish and refine CV&P
  • 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
  • Won’t get it right the first time
  • Will refine during the course of doing the model

MSIS 5653 - Advanced Systems Development

collect information and artifacts
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

MSIS 5653 - Advanced Systems Development

the author reader review cycle
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.

MSIS 5653 - Advanced Systems Development

identify candidate objects
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

MSIS 5653 - Advanced Systems Development

group objects into hierarchies
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

MSIS 5653 - Advanced Systems Development

define uob elaboration
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

MSIS 5653 - Advanced Systems Development

construct diagrams
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

MSIS 5653 - Advanced Systems Development

refine upwards and downwards
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

MSIS 5653 - Advanced Systems Development

building idef3 models
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.

MSIS 5653 - Advanced Systems Development

conclusion
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.

MSIS 5653 - Advanced Systems Development

when to do idef before idef3
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

MSIS 5653 - Advanced Systems Development

when to do idef3 before idef
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

MSIS 5653 - Advanced Systems Development

window types
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

MSIS 5653 - Advanced Systems Development

process flow nodelist window
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.

MSIS 5653 - Advanced Systems Development

process flow nodelist window64
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

MSIS 5653 - Advanced Systems Development

process diagram window
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.

MSIS 5653 - Advanced Systems Development

process object matrix window
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 object’s simulation type.

MSIS 5653 - Advanced Systems Development

ostn window
OSTN Window

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

MSIS 5653 - Advanced Systems Development

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

External Customer

MSIS 5653 - Advanced Systems Development

presentation features70
Presentation Features
  • In Presentation Display mode, you can drag elements into specific Swim Lanes represented by different color-codes.

External Customer

MSIS 5653 - Advanced Systems Development

model management
Model Management

PROSIM’s import and export capabilities allow you to exchange and convert between different IDEF model types.

  • Importing—Import models from other KBSI tools as well as text files you create.
  • Exporting—Export an entire project or a single model.

MSIS 5653 - Advanced Systems Development

importing activity models
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.

  • Activities—converted to processes and placed into the Process Pool.
  • Concepts—converted to objects and placed into the Object Pool.
    • Inputs > Entities
    • Outputs > Entities
    • Controls > Logicals
    • Mechanisms > Resources

MSIS 5653 - Advanced Systems Development

exporting
Exporting
  • Entire projects
  • Individual diagrams
  • Pools
  • Simulation models

MSIS 5653 - Advanced Systems Development

what is simulation
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.

MSIS 5653 - Advanced Systems Development

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.Processes & Simulation

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

MSIS 5653 - Advanced Systems Development

objects simulation
Simulation information for objects represents how the object participates in the process.Objects & Simulation
  • For entities, you can define:
  • How the entity arrives in the process
  • The number of entities arriving
  • The inter-arrival time of entity batches

MSIS 5653 - Advanced Systems Development

junctions simulation
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.

MSIS 5653 - Advanced Systems Development

exporting a prosim simulation model into witness

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.

running a simulation model
(1)

(2)

(4)

(3)

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).

p ro s im p roject l ink
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

Import a *.txt file into PROSIM

Save your work in an *.mpx format

MSIS 5653 - Advanced Systems Development

assignment 2
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.

MSIS 5653 - Advanced Systems Development

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