1. Workflow Description Language and Workflow Patterns Yi Wang

2. Outline What is Workflow? Workflow Management System Workflow Reference Models Workflow Description Language Workflow Patterns

3. Workflow Definition The automation of a business process, in whole or part. Information or tasks are passed from one participant to another for action, according to a set of procedural rules. A number of logical steps, each of which is known as an activity.

4. Example of Workflow

5. Example

6. Workflow Management System--Definition A system that completely defines, manages and executes “workflows” through the execution of software whose order of execution is driven by a computer representation of the workflow logic.

7. Three function areas --Supporting WFM  he Build-time functions, concerned with defining, and possibly modeling, the workflow process and its constituent activities The Run-time control functions concerned with managing the workflow processes in an operational environment and sequencing the various activities to be handled as part of each process The Run-time interactions with human users and IT application tools for processing the various activity steps

9. Types of Workflow Product FlowMark (IBM) Lotus Notes(IBM/Lotus) Ad hoc WorkMAN (Reach Software)

10. Workflow Reference Model A reference model for workflow management systems has been defined by the WfMC(Workflow Management Coalition). Specify a framework for workflow systems, identifying their characteristics, functions and interfaces.

12. WAPI Workflow Application Programming Interface The interface around the workflow enactment A service interface which is to support workflow management functions across the 5 functional areas.

13. Workflow Enactment Services A software service Consist of one or more workflow engines in order to create, manage and execute workflow instances. Applications may interface to this service via the WAPI.

14. Workflow Engine A workflow enactment service consists of mutiple workflow engines. A software service or "engine" Execute environment for a workflow instance Responsible for the part or all of the runtime control environment within an enactment service.

15. Process and Activity State Transitions The workflow enactment service may be considered as a state transition machine, Individual process or activity instances change states in response to external events(eg completion of an activity) Specific control decisions taken by a workflow engine(eg navigation to the next activity step within a process)

16. A Basic Example

17. Process Definition Tools To create model, describe and document a business process. Based on Process definition language Object relationship model A set of routing commands to transfer information between participating users

19. A Basic Meta-Model WFMC is developing a meta-model for the process definition Meta-Languages is a superset of constructs that is in process modeling languages

20. Workflow Description Language A process description, is a structure describing the tasks or activities to be executed and the order of their execution. The process description can be provided in Workflow Description Language.

21. Meta-Language for Workflow and Process Modeling WPDL(Workflow Process Definition Language) PIF(Process Interchange Framework) PSL(Process Specification Language) GPSG(Generalized Process Structure Grammars) Unified Modeling Language

22. A Business Process

23. Workflow Process Definition Language(WPDL) Defining the actions to be carried out in each possible state Pre- and post-conditions of states Transitions between states Defining the sequencing of tasks / states Defining automated states and states requiring user input

25. PIF Processes are presented at various levels of abstraction. Object-Oriented concept of inheritance. Hierarchy structure.

26. PIF

27. PSL(Process Specification Language) To support communication between different applications based on a common understanding of their environment. Develop a common exchange format for different modeling description.

28. A brief summary WPDL, PIF, PSL represent IPO-based process modeling languages. IPO(Input-Process-Output) IPO-based languages describe a workflow as a directed graph of activities, denoting the sequence of their execution.

29. GPSG Generalized Process Structure Grammars. A constraint-based approach to process modeling.

30. GPSG example For IPO-based language the sequence of two activities is denoted as B.start :=A.end For GPSG, contain following constraints B.start = A.end B.end < deadline B.start = B.end – B.average_duration

31. Unified Modeling Language Defines different diagram types for the design object-oriented software systems Helps you specify, visualize, and document models. Offers graphical notations for workflow models.

32. Workflow Patterns A process requires the activation of multiple tasks. Refers to the relationship among the tasks of a process. The workflow description languages and the mechanisms to control the enactment of a case must have provisions to support these temporal relationships.

33. Basic workflow patterns graph

35. Reference Internet-Based Workflow Management: Towards a Semantics Web. Dan.C.Marinescu. Wiley, 2002 Workflow:An Introduction. Rob Allen, Open Image Systems Inc., United Kingdom Chair, WFMC External Relations Committee Using Web Services and Workflow Ontology in Multi-Agent Systems. Jarmo Korhonen, Lasse Pajunen, and Juha Puustjärvi

36. Reference Workflow: An Introduction. Rob Allen, Open Image Systems Inc., United Kingdom. Chair, WfMC External Relations Committee. Workflow Process Definition Language- Development and Directions of a Meta-Language for Workflow Processes. Michael zur Mühlen, Jörg Becker Workflow Management Coalition The Workflow Reference Model Document Number TC00-1003 Document Status - Issue 1.1 19-Jan-95 Author:David Hollingsworth