Workflow Management: Models, methods and systems.

Wil van der Aalst

Eindhoven University of Technology Faculty of Technology Management Department of and Technology P.O. Box 513 5600 MB Eindhoven The Netherlands [email protected]

1 Overview of this course

Workflow management

Relation (Re)design of workflows with BPR With or without WFMS Resource management Logistical aspects COSA Analysis of workflows

Protos Concepts Guidelines Workflow management systems Techniques for modelling Interorganizational workflow Adaptive workflow

Based on Petri nets!

2 Outline of this course

• Introduction and motivation • (Re)design of workflows, • Business process reengineering guidelines, ... • Techniques for process modeling • Analysis of workflows •Petrinets •Case • High-level Petri nets • Functions and architecture of workflow management systems • Modeling business processes: workflow concepts • Hands-on COSA/Protos • Conclusion • Mapping workflows onto Petri nets • Resource management • Case/demo

3 Some trends

From programming to assembling!

EDM From data oriented DBMS to process oriented! GW OS From design EDI to redesign! WFM DSS ERP From controlled applications to organic!

4 Workflow management

Goal To manage the flow of work such that the work is done at the right time by the proper person.

Definitions A workflow management system (WFMS) is a software package that can be used to support the definition, management and execution of workflow processes. A workflow system (WFS) is a system based on a WFMS that supports a specific set of business processes through the execution of computerized process definitions

5 Relevance of workflow management systems

Trend: UIMS UIMS WFMS appl. appl. appl. appl. DBMS DBMS DBMS OS OS OS OS 1965-1975 1975-1985 1985-1995 1995-2005 Processes: • are becoming more important (BPR) • are subject to frequent changes • are becoming more complex • are increasing in number ⇒ Workflow Management System

6 The basic idea:

processes resources WFMS

applications

• separation of processes, resources and applications • focus on the logistics of work processes, not on the contents of individual tasks

7 Motivation In this course we concentrate on business process modeling

• Processes are important: – Business Process Reengineering (BPR) – Continuous Process Improvement (CPI) – Workflow Management (WFM) – Logistics Management (LM) • There are many modeling techniques and tools – DFD, ISAC, SADT, PN, HLPN, PA, FC, ... – Simulation tools, design tools, CASE tools, WFMS, ... • In this course we focus on the essential concepts by using a generic process modeling technique (Petri nets). • We focus on workflow processes.

8 Business Process Reengineering (BPR) (Business Process Redesign)

• Hammer and Champy: "Reengineering the corporation" (1993) •Keywords: – fundamental – radical – dramatic –process • The "organize before automate"-principle is replaced by "process thinking".

9 Processes and the

10 Continuous Process Improvement (CPI) • Instead of of seeking a radical breakthrough, optimizing the process by continuous, incremental improvements. • Part of the (TQM) approach ("doing it right the first time", "eliminate waste", ...)

high CPI BPR chaos BPR CPI impact change stagnation CPI BPR low CPI

low high time frequency

BPR and CPI are both process centric and can be supported by a WFMS.

11 Workflow versus workgroup computing • Workflow computing Workflow Management (WFM) Products: FlowPath, Staffware, ActionWorkflow, InConcert, OPEN/workflow, Workparty, COSA, .... – Emphasis on processes – Structured processes • Workgroup computing Computer Supported Cooperative Work (CSCW); Groupware Products: Lotus-Notes – Emphasis on the information (documents) being processed – Unstructured processes, sharing of information

12 structured (production) workflow

ad-hoc workflow

groupware unstructured

information process centric centric

13 human system oriented oriented

groupware

workflow

transaction processing

14 Aspects of workflow and workgroup computing

• process awareness (WFM) (tasks, routing, roles, ...) • management instrument (WFM) (measurements, control, ...) • allocating work to resources (WFM) (scheduling, priorities, ...) • documents (GW) (imaging, sharing, transport) • collaboration (GW) (interaction, cooperation, ...) • systems integration (WFM,GW) (integrating applications, legacy software, ...) • distribution (WFM,GW) (network, transparency, robustness)

15 We focus on workflow computing!

This is not a new idea, why now?

Enablers: • networks (hardware and software, client/server technology) • process thinking (BPR, CPI!) • dynamics of the environment of an information system – customer-driven – variety of products and services – cost reduction (more for less) • available WFM systems • extended enterprise, EDI, ...

16 Production/distribution logistics versus office logistics

• Clearly there are many similarities: (product-document, machine- human)!

• Differences: – making a copy is easy – quality is hard to measure and quality requirements are flexible – less restricting (physical) constraints » transportation is instantaneous » no bounded buffers » no fixed routing (real parallelism) – almost no stock (in most cases make-to-order)

Nevertheless, many principles and techniques (OR) can be used!

17 Architecture of a workflow management system

workflow definition tool analysis tools process definition simulation resource classification WFS

administrator workflow engine DBS EDI resources cases

in-basket application environment

18 Today's situation

• Estimate: more than 250 software producers are active in this domain. • Relatively, a limited number of actual sites. • Despite the efforts of the Workflow Management Coalition (WFMC) standardization is lacking. • Situation is comparable to the early seventies in '- land' (ER-model by Chen 76, Relational model by Codd 70). ⇒ We need a conceptual model for WFM ! ⇒ A unifying process modeling technique!

19 Process modeling techniques

• Process modeling techniques are used in many application domains (production/office logistics, information systems, technical systems). • Purpose: compare with building a house.

Purpose: (1) insight (2) analysis (3) building

20 Overview of process modeling techniques

• Flowcharts • Dataflow diagrams (DFD, ISAC, SADT, IDEF) • Transition systems, state transition diagrams (extensions: e.g. state charts) • Queueing networks and Markov chains • Process algebra's (ACP, CCS, CSP) • (High-level) Petri nets • Vendor specific diagramming techniques used in WFMS's, simulation tools and CASE tools.

21 Requirements • Formal semantics • Graphical • Easy to use • Easy to learn • High expressive power • Supported by tools • Not vendor specific • Explicit representation of states and events

We will use high-level Petri nets! We use transition systems/dataflow diagrams to illustrate this choice

22 Transition systems

• "mother of all process models" •low-level • easy to learn • difficult to apply • basic concepts: – state – state space –event

23 Basic concepts (static)

• State – e.g. state of an elevator (5,-1) 6 – snapshot of the process/system 5 • State space 4 – set of all possible states 3 – { (floor,direction) ∈ ΙΝ x {−1,0,1} | (1 ≤ floor ≤ 6) ∧ 2 ( floor = 1) ⇒ ( direction ≥ 0) ∧ 1 ( floor = 6) ⇒ ( direction ≤ 0) }

24 Basic concepts (dynamic)

• A process/system has a behavior, i.e. it moves from state to state state

time

25 Discrete dynamic systems

• We focus on discrete processes, i.e. state changes are caused by events

= event state

time

26 Example: elevator

6 • Graphical representation of a 5 transition system 4

3 (Abstraction from time!) 2

1

-1 01 27 Example: elevator (2)

•A possible path represented by a state/time diagram

(6,0) ... (3,1) state (3,0) (3,-1) (2,1) (2,0) (2,-1) (1,1) (1,0) time

28 Examples

spring winter red

yellow

green summer autumn

29 Examples (2)

start_course on follow_lecture

error exercise

off do_exam

pass drop_out

30 Dataflow diagrams

function/(sub)process B dataflow

A D

C

store Problem: informal!

31