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IDEF3

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IDEF3

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  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. MSIS 5653 - Advanced Systems Development

  3. 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

  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. MSIS 5653 - Advanced Systems Development

  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. MSIS 5653 - Advanced Systems Development

  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. MSIS 5653 - Advanced Systems Development

  7. 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

  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. MSIS 5653 - Advanced Systems Development

  9. 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

  10. Basic Elements of the Process Diagram Processes Links Junctions

  11. Processes Function Action Process Activity Act Operation Event Scenario Decision Procedure Represented by Verb-based Label Node # IDEF Ref # MSIS 5653 - Advanced Systems Development

  12. Links • Purpose • Describe temporal, logical, conventional, or natural constraints between processes • Types of Links • Simple Precedence • Object Flow • Relation MSIS 5653 - Advanced Systems Development

  13. 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

  14. 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

  15. 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

  16. 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

  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 MSIS 5653 - Advanced Systems Development

  18. 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

  19. Junctions Fan-in Fan-out XOR (X) AND (&) OR (O) X Asynchronous Synchronous & & O O Taxonomy of Junctions MSIS 5653 - Advanced Systems Development

  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 MSIS 5653 - Advanced Systems Development

  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 MSIS 5653 - Advanced Systems Development

  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 MSIS 5653 - Advanced Systems Development

  23. Documenting the Process Flow Process Elaboration Objects Referents Other Documentation

  24. Process Label Process # Elaboration Form Process Label: Process Reference Number: Objects: Facts: Constraints: Description: Process Elaboration MSIS 5653 - Advanced Systems Development

  25. 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

  26. Paint Part Objects 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

  27. 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

  28. 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

  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. MSIS 5653 - Advanced Systems Development

  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. MSIS 5653 - Advanced Systems Development

  32. 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

  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. MSIS 5653 - Advanced Systems Development

  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. MSIS 5653 - Advanced Systems Development

  35. Decomposition Decompositions allow you to break the process into pieces which are stand-alone processes. MSIS 5653 - Advanced Systems Development

  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. MSIS 5653 - Advanced Systems Development

  37. 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

  38. 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

  39. 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

  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). MSIS 5653 - Advanced Systems Development

  41. 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

  42. The IDEF3 OSTN Language Transition Arcs Object State Entry Conditions State Description Exit Conditions In the Object State Elaboration MSIS 5653 - Advanced Systems Development

  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 MSIS 5653 - Advanced Systems Development

  44. 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

  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. MSIS 5653 - Advanced Systems Development

  47. 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

  48. 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

  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 MSIS 5653 - Advanced Systems Development

  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. MSIS 5653 - Advanced Systems Development