1 Claude Godart & Hala Skaf-Molli, ESSTIN & UFR STMIA, UHP, Nancy 1 Workflow Concepts and Techniques...

Claude Godart & Hala Skaf-Molli, ESSTIN & UFR STMIA, UHP, Nancy 1 1

Workflow Concepts and Techniques

Claude Godart & Hala Skaf-Molli


Contents

• Where to get more information ?

• Business Process

• Workflow Definition

• Workflow Conceptual Model

• Benefits of Workflow Technology

• Workflow and Related Technologies

• Conclusion


Where to get more information?

• http://www.aiim.org/wfmc/– Workflow Management Coalition (WfMC):

– non-profit, International Organization of Workflow vendors, users and analysts..

– Define standards for the workflow system

– Reference model

– 180 Members: Microsoft, Oracle, Action Technology, DCE consultants, IBM, SAP AG, NEC ….


Where to get more information?• Tutorials:

– Workflow and Workflow management system, P. Peretti (Altan Group), Globecom Rio de Janeiro 1999

– Workflow Management in the Internet Age, C. Mohan (IBM Almaden Research Center), école d’été objets répartis, Grenoble 1999.

• Books– Production Workflow: Concepts and techniques, by F. Leymann (IBM)

and D. Roller (IBM), Prentice Hall.

– Workflow Technology in Computer supported Co-coperative Work, edited by Michel Beaudouin-Lafon

• On the Web– www.w4.fr

– www.teamware.com

– ….;


Business Process

• Procedures within an organization…

• A sequence of activities performed by various persons, the visible result being various pieces of paper.

• Example:– loan process in a bank– claims processing in an insurance company...


Workflow

• The automation of a business process, in whole or part, during which documents, information or tasks are passed from one participant to another for action, according to a set of procedural rules [WFMC].– Ensure that the right work is done at the right

time by the right people, in the right order.


Workflow

• We call the operational aspects of a business process-the sequence of tasks and who performs them, the information flow to support the tasks, and the tracking and reporting mechanisms that measure and control them-the workflow [Mohan99]


Processes and Workflow

Real World

Process Model

Process

Computer

Workflow Model

WorkflowIn

stan

ce

Inst

ance


Applications ExampleEvery time individuals co-operate to achieve a common

goal according to a predefined procedure workflow management is the appropriate tool.

• Insurance policy/claims processing (AVECOM)

• Loan request handling

• System administration (e.g. BDA activities)

• Healthcare claims (Empire Blue Cross Blue Shield)

• Order management (Microsoft)

• Travel expense approvals..

• Technical documentation creation

• Quality management

• Concurrent Engineering


Ex: Loan Request Handling

• Activities– Collect Credit Information – Assess Risk (amount > 10 000 FF)– Request Approval (amount > 10 000 FF or

High Risk)– Accept Credit– Reject Credit


Control flow of activities


Data flow

NameAddressRiskAmount

NameAddressRiskAmountName

AddressRiskAmount


Workflow challenge

• The workflow initiative promotes independence between process logic and programs

• as the database initiative promoted independence between process data and programs


Workflow Process Logic

• Two major facets:– Flow of control: the execution sequence of

activities…• nodes are activities, arcs are control connectors…

• transition condition is attached to a control connector...

– Data Flow : determines which paths should be taken..


Workflow Collaboratif Workflow de ProductionDocuments complexes et Documents à compléter/instruire :composites : - Contrat

- Document technique - Commande-Livraison - Document de recherche & facturation

- Publication

Workflow «Ad hoc» Workflow Administratif- Demandes spécifiques Traitements administratifs :- Gestion des cas particuliers - Processus d’achat

- Agendas, notes de frais- Gestion de personnel

Workflow Collaboratif Workflow de ProductionDocuments complexes et Documents à compléter/instruire :composites : - Contrat

- Document technique - Commande-Livraison - Document de recherche & facturation

- Publication

Workflow «Ad hoc» Workflow Administratif- Demandes spécifiques Traitements administratifs :- Gestion des cas particuliers - Processus d’achat

- Agendas, notes de frais- Gestion de personnel

Fréquence des processus

Valeur ajoutée des processus

Co

mm

un

icat

ion

Pro

du

ctio

n

Typologie et caractéristiques des

Workflow


Caractéristiques requises par type de Workflow 1/4

• Workflow de Production– Débit important (temps de réponse faible et bonne capacité de monter en

charge)– Puissant formalisme de représentation des procédures (procédures

définies de façon extensive)– Puissant environnement de développement et des outils d’intégration

avec les systèmes existants– Mécanismes d’affectation complets– Outil d’administration des opérations efficace (administration des

utilisateurs, des droits d’accès, des instances de procédure, statistiques)



• Workflow Administratif– Mêmes caractéristiques que celles du Workflow de production avec toutefois un

niveau de complexité et de richesse inférieur– Définition des procédures et activités sous forme graphique (limitation au

maximum de la programmation)– Présentation graphique des portefeuilles d’activités («worklists») fournie (agent)– Présentation graphique de l’historique des instances de procédures fournie (agent)– Support et distribution Internet afin de limiter le coût de déploiement



• Workflow collaboratif– Définition des procédures et activités sous forme graphique (gestion de sous-

procédures, réutilisation)– Modifications dynamiques de procédures– Présentation graphique des portefeuilles d’activités («worklists») fournie avec des

fonctionnalités de délégation, acceptation/rejet/re-soumission (agent)– Présentation graphique de l’historique des instances de procédures fournie (agent)– Support et distribution Internet afin de limiter le coût de déploiement



• Workflow Ad hoc– Produit très simple à utiliser (formation des utilisateurs en une demie-journée)

– Aucune programmation, toutes les définitions doivent se faire de façon graphique et sous forme de règles

– Limitation des fonctionnalités disponibles à l’essentiel afin de faciliter l’utilisation du produit

– Support et distribution Internet afin de limiter le coût de déploiement


Fréquence des processus

Valeur ajoutée des processus

•FlowMark(IBM)

•Visual Worlflo(FileNet)

•StaffWare(StaffWare)

•Lotus Notes(IBM)

•Ensemble(FileNet)

•TeamWare flow(TeamWare)

•In Concert(Xerox)



•StaffWare(StaffWare)



•W4(World Wide

Web Workflow)

•W4(World Wide

Web Workflow)

•EastmanSoftware Workflow(EastmanSoftware)

Positionnement des principales solutions

Source : Cap Gemini


Dimensions of Workflow

Three Dimensional workflow space W3 (what, who, which)

Process Logic

organization

IT Infrastructure


Workflow Management System

• A system that completely defines, manages and executes « workflow » through the execution of software whose order of execution is driven by a computer representation of the workflow logic [WFMC].

• Common characteristics:– basis for developing integration

– interoperability


WF system characteristics


Running Activities

Activity

Input ContainerOutput Container

WorklistWorkitem..

Program

1

2

3

4

5

1: user click (manual activity)

2: WfS: builds input container

3: Wfs call program

4: access database

5: put new value in output container


Modèle de référence WFMC


Workflow system’s components

• Build-time functions : flow modeling component– administrators and analysts to define processes

(procedure) and activities– analyze and simulate them– assign to participant specifications– view work process statistics– make change to process



• Run-time process control functions : workflow execution (enactment) in an operational environment– workflow engine

• process creation and deletion

• activity scheduling

• interactions with application tools and human resources



• Run-time activity interactions with humans users and IT application tools functions :– transfer control between activities– tool invocation and data passing– workflow interperability


Execution d’un WF


Workflow Concepts

Activity Process Role

Operation Flow of control Actor

Task Transition Position

Step Route User

Work Path Group

Job Resource

Staff

Organizational unit

A lot of words around workflow

What is done Relationships among Who doesthings done


WfMC process definition meta-model Process definition

Process activity Process

relevant data

TransitionInformation

Sub-process

Atomic activity

consists_of

implemented as

from to

Participantspecification

executed_by

may use

Loop

Applicationdeclaration

*

* *

* *

**

** *

may use

*

Participantspecification

may reference


Process

• Workflow process (or procedure) is the automated parts of a business process

• A coordinated set of activity(s) that are connected in order to achieve a common goal.

• Example:– « order processing procedure » Engineering– « claims administration process » : Insurance


Activity

• The body of a work step of a process.– Compound activity: another process.– Elementary activity: a basic set of work;

sequential set of primitive actions executed by a signal participant.

• 3 modes: automatic, manual, mixed..


Activity Example

• Process: «order equipment» has 3 work steps:1. Order entry

2. Credit check

3. Billing

4. Shipping

1. automatic; 2. manual; 3. automatic; 4. mixed


Activity Example

2. Credit check

2.1. log request

2.2 gather data

2.3 evaluate

2.4. fill out report form


Process instancestate-transition

Initiated

Suspended

Running Active

resume

restart

suspend

Completed

Terminated

Initiate

abort

terminate

Iterate through all active activities

start


Activity instancestate-transition

Initiated

Suspended

Running Active

resume

restart

suspend

Completed

Terminated

Initiate

abort

terminate

Iterate through all active activities

start


Transition information

• AND Join parallel activities converges into single activity with synchronization..

• OR join parallel activities converges into single activity without synchronization..

• AND Split single activity splits into two or more parallel activities ..

• Or Split single activity makes a decision upon which branch to take when encountered with multiple branches

• start, end...


Transition information

A

B1

B2

B3

C

Parallel Processing

AND-split AND-join OR-split OR-join

A

B1

B2

B3

C

Conditional Branching

A

B1

B2

B3

C

Parallel Branching with final selection

Fork activityJoin activity


Example: Make some coffeeStart

Finish

A

BC

D

Start

Finish

A

B

C

D

A. Fill the kettle (Remplir la bouilloire)

B. Place coffee in cups

C. Heat the water

D. Pour hot water on coffee

A, B, C, D are activities Plans


Work case (Job)

• An instance of the process

• Has its own data

• Example:– 2 loans request from Micheal, Jean

=> 2 work cases– Micheal Loan request– Jean Loan request..


Role

• Basis for access control and execution control.• The execution of activities is associated with roles

rather than end-user => flexibility; handle exception..

• Ex: “order entry activity” is executed by the order administrator (not by Micheal :-)

• Role: associated with an actor; a group of actors..

• Ex: order administrators; «send to all»


Participant

• A person, program, group or entity that can fulfill roles to execute, to be responsible for…

• Human participant is an actor...


0,n

0,n

0,n

0,n

0,n

1,1

0,n

0,n

0,n

0,n

0,nnext

0,nprevious

1,n

1,n

Process Participant

Data

Activity

Role

Job

Implication

Precedence

Use

Play

Responsible

State

Execution

Workflow Conceptual Architecture


More About Activities

Join ConditionActivation Condition/Mode

Query on Organization BDProper Implantation

Exit Condition

TASK

UserIdImplementation

Worklist(UserID)Workitem1

workitem2

...

Workitems

Fine Structure of Activities


Activity state transition diagram

Inactive Ready Executing

InError Executed

CheckOutTerminated

Finished

ExpiredSkipped


Different Types of Activities

• Information Activity:– do some action (call a customer)

• Program Activity– separation between conceptual and implementation

– different implementation according to OS(Windows NT, AIX,..)

• Process activity:– activity is implemented by a subprocess..

• Bundle Activity:– executed multiple times (Compilation activity)..


Subprocess

• Local subprocess

• Remote subprocess (same or different vendor WF)

• Subprocess behaves w.r.t its parent:– Autonomy model: his own life, not affected

when parent terminate….– Connected discrete Model– hierarchical Model


Autonomy model

• Has his own life

• Autonomy rules define relation with parent

• if completely autonomous then parent termination does not affect the subprocess


Connected Discrete Model• Two processes A, B..

• An activity of A causes the creation of an instance of B

• A and B are independent ...

• Chained services model

A1

A2

A3

A4

A5 B1

B2

B3

B4

B5

Process AProcess B


Hierarchical Model• Two processes A, B..• An activity of A causes creation of an instance of B• A waits B • Nested Model

A1

A2

A3

A4

A5 B1

B2

B3

B4

B5

Process AProcess B


Why Workflow Technology

• To streamline, coordinate and monitor an organizational process involving human and automated tasks spread across multiple enterprises with heterogeneous (existing and new) computing environment.

• Some products focus on one aspects of workflow technology, primarily to reduce paper work or coordinate activities among humans:– document management, e-mail routing, etc...


Benefits of Workflow Technology• For customers:

– Gain improved insight into the processing of their work cases.

– Response time,

– Quality of services and accuracy of status are enhanced.

• At enterprise level– Organize, schedule, control and monitor process

– Improve productivity

– Reduce paper work…

– reinforces security and confidentiality ..

– The image of the enterprise is improved


Benefits of Workflow Technology

• For the enterprise staff– Employee has more accurate view of his tasks

– External pressures for increased efficiency– No need to spend time and effort to control the organization

of work cases...

– Internal pressure for increased effectiveness– Desire by workers for more reward and less stress !!

• For the line management (supervisors)– just in time information to make decision to improve

tasks !!


Benefits of Workflow Technology

• For the top management– formally describe the processes of an enterprise

– improve process

– Workflow also helps to quickly educate new or temporary actors.

• In general:– Support on-line data entry, Support data exchange and transactions

across independent enterprises (EDI)

– In most general form, workflow technology can be used to support programming-in-the-large..


Be Careful !

• Workflow must be flexible…• Must not kill creativity of people..• Must be accepted by people..• No successful story of Wf from 1970 to 1980

because of people rejection (don’t take in consideration social and organization setting) …

• Workflow are people systems


Example Systems

• IBM FlowMark

• Action Workflow

• Polymer

• TeamWare Flow


TeamWare Flow

• Client/Server

• TeamWARE Flow:– server software,– a database, – a document management system, client tool

applications – and an Application Programming Interface

(RCAPI).


Architecture


TeamWare

• Server side:– data base (SQL server, Oracle or Sybase)

• data + process states and history..

– DMS : document attached to a process– BUS: TCP/IP..


Workflow and Related Technologies


Workflow and Related Technologies

Workflow Technology

SystemManagement

Multidatabases

InternetApplication

Development

ObjectTechnology

Operating Systems

BusinessEngineering

MobileComputing

TransactionManagement


Research Discipline Contributing to Workflow Management

WfMSReengineeringmethodology

Quantitative andFormal Methods Organizational

Science

SGBD

CSCW

DistributedComputing

SoftwareEngineering

SoftwareProcess


Workflow and Objects

• What is the relationship between objects technology and workflow technology ?– Objects to implement activities…

– workflow as objects

• Component-based Software Construction

• OMG OO framework to manipulate workflow..


Component-based Software Construction

• Use prefabricated software artifacts in building new applications functions…

• Artifact: “Business Object”

• Scripting: build new application function out of business objects


Business Objects

• Objects that are related to the business of the enterprise: customer, credits

• As software objects:– things from reality..

– self-contained entities: what can be done with…

– reusable: account object, payment, funds transfers,…

• object used for scripting applications functions components


Components technical proprieties

• Language independent …

• Interoperate with as many different tools as possible: capability to query metadata about itself..

• Interoperate across operating systems and networks..


Scripting

• Plug components together..

• Script specifies in a simple way how component must behave: properties and methods…

• Scripting language: simple, no declaration...


Example: The Loan Request Implemented with Objects

Amount

Credit

check

Customer

reject

ResponseLetter

confirmResponseLetter

cr.Amount()>10000

cr.Amount()<=10000 Cus.check= “OK”

The business objects methods are used to specify the proper sequencing...


Utiliser visual builder: Example: Alarm Bean et JugglerBean...

Java beans


Scripting language vs process model

• Script must be specified as process model, if one on the following is true:– forward recoverable: problem during execution,

resuming execution where it left... • persistent state

– components run in parallel, distributed, in heterogeneous environment

• synchronization

– different programming language for the components

– backward recovery..


Scripting language vs process model

• Component in script are not launched automatically but on explicit request from external parties..

• Data flow facilities: input parameters of a component are constructed from the output of several preceding components...


Workflow and Objects

• OMG propose workflow management facility..• Add runtime functionality of a workflow

management system to an ORB (Object Request Broker)..

• OMG standard defines a collection of interfaces in IDL (process manager interface, activity interface,…)

• No implementation...


Workflow and transactions


Why Transactional Workflow ?

Parts of Travel reservation of “traveluck”, Inc



Data Sharing Semantics



Failure Semantics


Transactional Requirements• Need to specify data sharing semantics• Need to specify failure semantics:

– which parts of workflow behave as a whole (atomically)

• Reliable workflow process requires transaction mechanism !

• Put the transactional properties:– at activity level: secure customer payment..

– at several activity level :consistency of the whole system..


Standard Transactions• A transaction is a set of actions..• ACID Properties

– Atomic (all or nothing)

– Consistent (by the programmer)

– isolation (no visibility of intermediate results)

– Durable

• Correction Criterion: Serialisability– concurrent execution of transaction is correct if

equivalent to serial execution (same read set and final results..)

• Correction protocol : 2PL (2 Phases Locking)


Standard Transactions

• Distributed transaction (Global transaction): more than resource manager– hotel reservation, flight reservation..– Atomic commitment:

• 2PC protocol...


Advanced transaction models

• A lot of models (database transaction Models, Ahmed K. Elmagarmid92)

– Nested transaction[Moss 82]..– Saga [Garcia-Molina and Salem 87]– ConTracts [Reuter 89]– Multi-bases transactions– S-transactions


Nested Transaction • Decompose a “large” transaction into a collection of

transactions..

t1

t12 t22

t21t22 t23 t24


Nested transactions• Each transaction can commit or abort

• The root transaction can commit or abort

• The commit of a transaction will only become effective if its predecessor transaction commits

• if a transaction aborts, all transctions of its subtree are aborted too.

• Modifications on resources of a transaction become visible to its immediate predecessor transction (« parent ») iff the transaction commits ...

• Modifications on resources of a transaction are only visible to the transaction itself and its successor transactions (« children ») ...


Open Nested Transaction• Objective: increase the throughput …• idea : giving up the isolation properties

– the effects of a committed transaction are visible to all transaction and not only to its parents…

• Problem: t12 abort, t21 has committed– undo only t21 not possible and not sufficient, why ?

• Solution: compensation functions• Example:

– credit and debit, reserve and cancel…

– complex compensation: compensating deposit transaction after days !!!!!


Saga• Add the capability to automatically

determine and start compensation functions to the environment..

• A saga is defined as a sequence [(T1,C1),…(Tn,Cn)] that having the following properties:– T1,…Tn and C1,..Cn, Ci compensation

function of Ti


Saga

• [(T1,C1),…(Tn,Cn)] is executed as one of the following sequences:– a. [T1,…Tn] if all Ti committed– b. [T1…, Ti,Ci-1,….C1] if Ti aborts and

T1, …Ti-1 committed before

– used in (IBM FlowMark Workflow)...


ConTracts

• A consistent and fault tolerant execution of an arbitrary sequence of predefined actions (called steps) according to an explicitly specified control flow description (script)

• A step an unit of work, is ACID transaction..

• Atomic works are implemented ...


Forward Recovery

• For each step there is an compensating step

• This is not a rollback of the step…– the context of ConTract variables, windows, files,

data) execution is persistent

• There is a correction criterion for compensation...


S1 S2 S3 S4 S5 S1

S2

S2

Traveldatainput

Checkflight schedules

Flightreservation

Hotel reservation

Carrental

Print documents

S6 S7

failureBegin ofContract

End ofConTract

S8

Trip reservation

Cancel reservation

failure

3 airlinesare consulted

2 Hotel andcar companies


ConTracts

• Minimal loss of work in case of failures

• Forward recovery after a failure

• Fault-tolerant run-time system


(Distributed) Transaction Processing (DTP) Vs. Advanced WfMs

• DTP/D-OLTP is focused on efficient execution of relatively simple tasks with no coordination across heterogeneous tasks …

• Advanced Workflow requires coordinated execution of heterogeneous tasks, with varied level of transactional properties, on a variety of systems..


(Distributed) Transaction Processing (DTP) Vs. Advanced WfMs

Task groups in DTP

Task task1

Workflow group in advanced WF

task2

task3

task4


Conclusion

• Transactions are important for reliable workflow semantics

• standard ACID transaction model too restricted for workflow

• Advanced transaction models can be a good solution...

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