PART VII - Workflow Management Systemslsir · • Workflow Management systems make this function...

©2001, Karl Aberer, EPFL-DSC, Laboratoire de systèmes d'informations rèpartis

PART VII - Workflow Management Systems

1. Overview1. Motivation2. Terminology

2. Process Modelling3. Workflow Management Systems

1. Types of Workflow management systems2. WfMS architectures3. Crossorganizational workflows4. Example: WebLogic Process Integrator

4. Summary5. References


1. Overview

• 1.1 Motivation• 1.2 Terminology


1.1 Motivation

• Process focus in modelling an information system– Data focus: e.g. relational data model and databases– Functional focus: function interfaces and transaction monitors– Behavioral focus: object models and object transaction monitors– Process focus: process models and workflow management systems

• Why focus on processes ?– At coarse granularity a business process describes best what a company is

doing– Business process re-engineering is a practice to understand and optimize

what a company is doing– At a coarse granularity large systems can be best described as processes

(programming in the large)– The interaction of many different information systems and human users can be

best captured by processes (linking data islands)


Example: Damage Claim Handling Business Process

receive call

assign garage

notify insurance

notify adjustor

contact garage

receive car

estimate cost

assign adjustor

inspect car

agree repair

repair car

invoice

checkinvoice

fill claim form

amend estimate

reconcile info

finalize claim

estimate < 500

insurance WFMS

GARAGE

CALL CENTRE

INSURANCE


System Activites in a Business Process

• Activities in a business process can be human- or system controlled• The activities can access (shared) applications and databases• Business process can be distributed within and among organizations

Source: WfMC


The Role of Workflow Management

Process ProcessSpecification

Process Execution

Business ProcessModelling and Reengineering

Workflow Enactment

Workflow AnalysisSimulation

runtimebuildtime

Interactionwith humans and IT tools


Benefits of Workflow Management Technology

• Organize, schedule, control and monitor process • Help understand/improve process

– analysis, simulate, reengineering

• Make processes more efficient– Reduce paper work– Support on-line data entry where data originates– support data exchange and transactions across independent enterprises (EDI)

• More generally workflow technology can be seen as"programming-in-the-large"


1.2 Terminology

• A Process is – a collection of activities related to a specific case (commitment)

• each damage claim represents a single case• all damage claims (the same case) constitute the damage claim handling process

• An Activity is – a collection of events, a set of logically related operations or a bounded

computation – that can be made to occur by a single logical actor (e.g., by a person with a given

role) or a processing entity (information system, resource manager)• review a damage claim assessment• fill out a complaint form• perform a database transaction

• An Organizational Process is – a collection of activities related to a specific case, adding value to a product of an

organization.• processing damage claims in an insurance company


Terminology

• Workflow Management (WFM) is – the automated coordination, control, and communication of work– both of people and computers– in the context of organizational processes– through the execution of software in a network of computers – whose order of execution is controlled by a computerized representation of the

business processes

• A Workflow Process is – an automated organizational process– the automation of a business process, in whole or part, during which documents,

information, or tasks are passed from one participant to another for acting, according to a set of procedural rules [WfMC]

• processing damage claims in an insurance company “orchestrated” by a workflow management system

• A Workflow Management System (abbreviated WFMS) is – a technological system – in which workflow processes are defined, performed, managed, and monitored – through the execution of software – whose order of events is driven by a process definition


Terminology

• A Work Item is– a message that represents work to be performed.– is used to manipulate (e.g. relay, store, schedule) work for the purpose of doing

it later or elsewhere• a fax asking about the damage claim assessment that should have been there 3 days ago.

• A Data Item– An object that represents information, which is needed to perform some activity

• a photograph of the damage, taken on location

• A Work List is– list of work items retrieved from a workflow management system.– a worklist is used by an actor as a to-do list


Relationships among Concepts

Business Process

Workflow Management System

Process Instances

Activity Instances

Work Items Invoked Applications

Process Definition

Sub-Processes

Activities

Manual Activities Automated Activities

Which may be

or

Is defined in a(i.e what is

intended to happen )Is managed by

(controls automated aspects of thebusiness process via)

Include one or more

(a representation of what is actually happening)

(tasks allocated to a workflow participant)

(computer tools/applications used tosupport an activity)

Which include

And/Or

(a representation of what is intendedto happen)

Composed of

(which are not managed as part of the Workflow system)

During execution are represented by

Used to manageand create

Source: WfMC


2. Workflow Modelling


Elements of Workflow Models

• There exist almost as many workflow models as workflow systems• Usually a workflow model distinguishes

– Process definition– Resources– Resource management rules

• Process definition– Description of the process– Activities, usually executed atomically with internal state model– Control and data flow among them– Subprocesses

• Resources– Classes of resources that can be used to execute an activity


Process Definition: Control and Data Flow in Processes

Activity 1

Activity 2

Activity 4

Activity 3

Estimate≤100

out In out

Control connector

Data connector

Transition condition

Variable(Data container)


Control Flow

• Each workflow has well-defined start and end node

• Sequential Execution

• Parallel Execution– Both activities executed in parallel– Workflow continues when both

activities are completed– AND-split and AND-join

• Choice– On of the alternative activites executed– Decision made based on variable values– Workflow continues when one

activitiy completed– OR-split and OR-join

Activity 2Activity 1

Activity 2

Activity 1

Activity 2

Activity 1

Activity 1S E

cond


Example: Damage Claim Process

receive call

assign garage

notify insurance

notify adjustor

contact garage

receive car

estimate cost

assign adjustor

inspect car

agree repair

repair car invoice

check invoice

fill claim form

amend estimate

reconcile info

finalize claim

S

E

estimate < 500


Sub-workflow

• A workflow activity itself can be a whole sub-workflow– The sub-workflow has one ingoing and one outgoing control connector

Activity 1S E

Activity 2Activity 1S E


Workflow Instance

• A workflow specification is instantiated in runtime – Multiple instances of the same workflow (cases)– State is given by the currently active activities and their internal states– Multiple instances of the same activity types can be instantiated

• Internal states of activities

Source: WfMC


Global States of Workflow Instances

• A workflow instance has also a (global) execution state associated with

Source: WfMC


Resources

• Resource (participant, actor, user, agent)– A resource can execute certain activities for certain cases– Human or non- human (printer, modem)

• Resource class is a set of resources with similar characteristics• A resource class is typically based on

– Role (skill, competence, qualification)• Classification based on what a resource can do

– Group (department, team, office, organizational unit)• Classification based on the organization

• The workflow specification contains rules that specify by whom an activity can be performed


3. Workflow Management Systems

• 3.1 Types of Workflow management systems• 3.2 WfMS architectures• 3.3 Crossorganizational workflows• 3.4 Example: WebLogic Process Integrator


3.1 The Evolution of Workflow Systems

• A number of technologies incorporated workflow-related functions– Image processing– Document management– Electronic Mail– Groupware Applications– Transaction Applications– IT Project support software– Business process reengineering and system design tools

• Workflow Management systems make this function explicit and support by means of a dedicated system– Stand-alone workflow management systems (e.g. Flowmark)– Embedded workflow management systems (e.g. SAP)– Workflow management middleware (e.g. Weblogic Process Integrator)


WfMS Architecture

• Message oriented (the “lightweight” approach)– workflow process definition is part of messages

• Repository oriented (the “heavyweight” approach)– workflow process definition is stored in a repository/database

• Trade-off– infrastructure technology needed, robustness, ease of modification


Message-oriented Architecture

• Origins in enhanced e-mail systems and electronic forms• Flow of structured messages between performers/users

– messaging model

• Process definition part of messages – usually not stored in a repository

• Lack of accessible and manipulable process definition => difficulty in – knowing status (monitoring) – progress (tracking)– reuse

Activity 1

Activity 2

Activity 4

Activity 3

System 1

System 2

System 4

System 3


Repository-oriented Architecture

• Modeling of execution of process components• Formal process model (e.g., petrinets)• Both local view of individual execution component (worklist) and of

complete process• Repository of definitions to support reuse• Use of databases or common/shared storage

– usually supporting monitoring, tracking

Workflowsystem

Activity 1

System 1

Activity 2

System 2

Activity 3

System 3

Activity 4

System 4


Types of Workflow Systems

Informationcentric

Processcentric

unstructured

structured

groupware

ad-hoc workflow

production workflow


3.2 Workflow Engines as Middleware

Application Database

activity 1 activity 2

activity 4

activity 3

Wrapper Wrapper

Workflow client

Workflow engine

AdministrationMonitoring

Process definition

Otherworkflow engines

Data server

Workflowdata


Implementation Architectures (repository-oriented)

Source: WfMC


The WfMC Reference Model

Source: WfMC


WfMC Interfaces

• Interface 1: Workflow Definition Interchange– Exchange of workflow definitions between modelling and runtime tools– Based on a process meta-model– Standard API calls to read an write process definitions

• Interface 2: Workflow Client Application Interface– Access of applications to the workflow engine and the worklists– Process and activity control functions

• Interface 3: Invoked Applications Interfaces– Interface for workflow-enabled applications– Start/suspend/resume/abort activity– Notification of workflow engine– Data handling

• Interface 4: Workflow Interoperability Interfaces– Invocation and synchronisation of processes and activites across workflow

engines• Interface 5: Adminstration and Monitoring Interface

– User/role management– Audit management (event log)– Resource control– Process supervision and status querying


3.3 Workflow Interoperability

Source: WfMC

chained

subworkflow

synchronised

shared


Workflow Interoperability Models

• Chained– Control is passed on from one workflow to another without any further

interactions

• Subworkflow– One workflow system performs a subworkflow on behalf of another one

• Synchronised– Activities from different workflow synchronise via notifications

• Shared– A shared workflow process is executed by different workflow engines


3.4 Weblogic Process Integrator

Source: BEA


Weblogic Process Integrator Process Model

Source: BEA


Events in Weblogic Process Integrator

• The event node allows a workflow to enable control connectors based on the occurrence of (external) events– Events can be incoming XML messages– Interoperability with other systems (synchronised model)


Summary

• Workflow management systems support– Explicit process specification and enactment– Thus useful for business process (re-)engineering and optimization and

programming in hte large– Process model define the control and data flow between the activities

• Workflow management systems– Are a process-oriented middleware– Can be implemented in a message-oriented or repository-oriented fashion– Are standardized by the Workflow Management Coalitions models

• Advanced problems– Flexibility in workflow models– Treatment of exceptions and time– Interoperability of workflow systems


References

• Books– F. Leymann, D. Roller: "Production Workflows", Prentice Hall, 2000.

• Websites– Workflow Management Coalition: www.wfmc.org– Weblogic Process Integrator: edocs.bea.com/wlpi


Exams

• Oral exam• Basis for the exam

– The script– The exercises– The reading list: 10 - 11 articles providing more detailed information on a topic

• 2 questions– Q1: you can choose 3 reading topics from the reading list, the questions on this

topic will be technically more detailed– Q2: a question on a more conceptual level based on the script

• Motivation: there exists 4 levels of acquaintance with a topic– Knowledge of names (who ?) - hopefully you heard them– Understanding of concepts and their relationships (what ?) - Q2– Understanding the technical details and algorithms (how ?) - Q1– Mastering the technology (do it) - Exercises


Reading List

• Part 1– XSL Transformations: XSLT Alleviates XML Schema Incompatibility Headaches, Don Box, Aaron Skonnard, John

Lam (html document)– XML Schema Part 0: Primer, W3C Candidate Recommendation 24 October 2000 (html document)

• Part 2– Federated Information Systems: Concepts, Terminology and Architectures, Susanne Busse, Ralf-Detlef Kutsche,

Ulf Leser, Herbert Weber, Forschungsberichte des Fachbereichs Informatik, Bericht Nr. 99-9 (pdf article)

• Part 3– Using the Web DataBlade Module (html document -

http://examples.informix.com/frameset.html#top?initial_page=/doc/case_studies/datablade/apb/apbLOC.html)

• Part 4– Database Technologies for Large Scale Databases in Telecommunication, Eurescom Deliverable, Part 1:

Transaction Processing Monitors (pdf document)– OMG Transaction Service Specification, ch 1-2 (pdf document)– R. Ramakrishnan, J. Gehrke, "Database Management Systems", McGraw Hill, 2000. - ch 18, 19, 20 on transaction

processing (paper copies - available at LSIR secretary)

• Part 5– M. Henning, S. Vinoski, Advanced CORBA Programming with C++, Addison Wesley, 1999. - ch 2, 3, 11 on CORBA

and POA (paper copies - available at LSIR secretary)

• Part 6– Introduction to BEA WebLogic Server 5.1 (html document)– R. Monson-Haefel, "Enterprise Java Beans", O'Reilly, Second Ed., 2000. - ch 2, 3, 6, 7 on the EJB model (paper

copies - available at LSIR secretary)

• Part 7– Workflow Management Coalition: The Workflow Reference Model (pdf document)

• Part 8– Biztalk Framework 2.0 (Word document) and Biztalk server example (html document)


Semester project -The P2P Information Systems Algorithm Project

• Take part in an exciting endevaour we are undertaking at LSIR !• Goal

– systematically analyse whether and how existing algorithms for accessing large information collections can be implemented in a P2P fashion

– Java-based testbed – P2P information systems will be the hot topic over the next years on the Internet

and in business computing– Buzzwords: Gnutella, FreeNet, MojoNation, …

• Algorithms that are added to the library – accessing databases (typically indexing methods):

• Examples: B-Trees, kd-Trees, Trie structures, ...– information retrieval:

• Examples: Vector retrieval model, latent semantic indexing model, Bayesian model, ...– data mining and distributed decision making:

• Examples: Classification methods, association rule mining, cluster analysis, ...

• Approach– choice of the specific algorithm left to you (if you wish)– the semester project can serve as entry to a larger subsequent diploma project– this project matches perfectly the contents of the lecture "Distributed Information

Systems"• contact [email protected] in case you are interested in the project

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PART VII - Workflow Management Systemslsir · • Workflow Management systems make this function...

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