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Achieving Dynamic Inter-Organizational Achieving Dynamic Inter-Organizational Workflow Management by Integrating Business Workflow Management by Integrating Business Processes, E-Services, Events and RulesProcesses, E-Services, Events and Rules

Jie MengJie Meng

Ph.D. CandidatePh.D. Candidate

CISE DepartmentCISE Department

January 04, 2002January 04, 2002

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OutlineOutline IntroductionIntroduction Related ResearchRelated Research Architecture of DynaFlowArchitecture of DynaFlow Dynamic Workflow ModelDynamic Workflow Model

– E-ServicesE-Services– Dynamic Workflow ModelDynamic Workflow Model– Workflow Event DefinitionWorkflow Event Definition– Dynamic Properties of DWM and DynaFlowDynamic Properties of DWM and DynaFlow

DynaFlow DesignDynaFlow Design DynaFlow ImplementationDynaFlow Implementation

– Code Generation ApproachCode Generation Approach– Workflow Engine ArchitectureWorkflow Engine Architecture– Run-time Modification to a Process ModelRun-time Modification to a Process Model

Summary and Future WorkSummary and Future Work

This research project is supported by an NSF grant #EIA-0075284.This research project is supported by an NSF grant #EIA-0075284.

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MotivationMotivation

Global marketplace is competitive and changing Global marketplace is competitive and changing Internet gains a great successInternet gains a great success Trend of publishing services on Internet emergesTrend of publishing services on Internet emerges Different organizations need to work togetherDifferent organizations need to work together

Virtual Enterprise

Dynamic Inter-organizational Workflow

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Inter-organizational Workflow should be Inter-organizational Workflow should be DynamicDynamic

Business processes need to be integrated with business Business processes need to be integrated with business events and rules. The rules can:events and rules. The rules can:– In turn enact other business processes or do some work (active).In turn enact other business processes or do some work (active).

– Enforce customized business constraints and policies Enforce customized business constraints and policies (customizable). (customizable).

Runtime modifications to process model should be Runtime modifications to process model should be supported (adaptive).supported (adaptive).

Dynamic binding of service requests made in a process Dynamic binding of service requests made in a process model to services and their providers should be supported model to services and their providers should be supported (flexible).(flexible).

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Our SolutionOur Solution

Basic idea: Basic idea: use dynamic inter-organizational workflow use dynamic inter-organizational workflow technology to integrate distributed and heterogeneous technology to integrate distributed and heterogeneous services.services.

Develop a Develop a dynamic workflow model (DWM)dynamic workflow model (DWM) by extending by extending WPDL to enable the specification of dynamic properties WPDL to enable the specification of dynamic properties associated with a business process model.associated with a business process model.– Treat sharable tasks in a virtual enterprise as Treat sharable tasks in a virtual enterprise as e-servicese-services..

– Propose constraint-based Propose constraint-based dynamic service binding dynamic service binding technology.technology.

– Integrate business processes with Integrate business processes with events and rulesevents and rules. .

– Provide Provide run-time modificationrun-time modification to process models. to process models.

Build a Build a dynamic workflow management system (DynaFlow)dynamic workflow management system (DynaFlow) as a part of the ISEE Infrastructureas a part of the ISEE Infrastructure

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Related WorkRelated Work WfMCWfMC

– Workflow Reference ModelWorkflow Reference Model– WPDLWPDL

Workflow Projects that Make Use of Events and RulesWorkflow Projects that Make Use of Events and Rules– WIDE: Events and rules are used for exception handling.WIDE: Events and rules are used for exception handling.– EvE: Events and rules are used for EvE: Events and rules are used for defining and enforcing workflow logic. A

distributed ECA rule-based enactment architecture is also investigated in EvE. Run-time Modification to Process ModelRun-time Modification to Process Model

– ADEPT_flex.ADEPT_flex.– Rule-based approach.Rule-based approach.

Virtual Enterprise and Workflow TechnologyVirtual Enterprise and Workflow Technology– WISEWISE– CrossFlowCrossFlow

Web Service TechnologiesWeb Service Technologies– SOAPSOAP– WSDLWSDL– UDDIUDDI– WSFLWSFL

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ISEE InfrastructureISEE Infrastructure

App

Internet Communication Infrastructure

Agent ADODOBrowser

ISEE Infrastructure

. . .

Manufacturers & Suppliers

Warehouses & Distribution Centers

Retailers

Transportation Companies

ISEE HubISEE HubISEE Hub

ISEE HubISEE Hub

OtherServersOther

Servers

ISEE-HUB

NegotiationServer

NegotiationServer

WorkflowServer

WorkflowServer

Security Server

Security Server

ETRServerETR

Server

EventServerEventServer

WebServerWeb

Server

...

Internet Communication Infrastructure

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Internet

ISEE Hub

ISEE Hub

Broker Server

ISEE Hub

E-Services

E-Service Adapter

Organization 3Organization 2

Organization 1

Workflow Server Broker Proxy

ETR ServerEvent Server Web Server

E-Services

E-Service Adapter

E-Services

E-Service Adapter

E-Services

E-Service Adapter

Organization 4

Architecture of Architecture of DynaFlowDynaFlow

Workflow Server Broker Proxy

ETR ServerEvent Server Web Server

Workflow Server Broker Proxy

ETR ServerEvent Server Web Server

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Components in DynaFlowComponents in DynaFlow

Process Definition Tool

ISEE Hub

E-Service Adapter

E-Services

ISEE Hub

Post Async Events

Post Sync Events

Service Invocation

Distribute Events

Event Server ETR Server

Broker Server

WF Engine

Install events, triggers and rules

Install WF Events

Forward Events

Generate Runtime WF Structures

Receive Events

Receive Events

Broker Proxy

Service Provider Inquiry

Knowledge Profile Manager

Invoke

Distribute Events

ISEE Hub

Browse E-Service Information

INTERNET

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E-ServicesE-Services E-Services E-Services are services offered on the Internet that can be are services offered on the Internet that can be

accessed programmatically using a standard Internet accessed programmatically using a standard Internet Protocol and representation format like HTTP and XML.Protocol and representation format like HTTP and XML.

Categorize e-services by the Categorize e-services by the types of business types of business that the that the providers conduct.providers conduct.

For each type of e-service, a For each type of e-service, a e-service templatee-service template is defined is defined to standardize the specification of an e-service.to standardize the specification of an e-service.

E-service templates are managed by the Broker Server. E-service templates are managed by the Broker Server. Service providers register the e-service they provided to the Service providers register the e-service they provided to the

Broker Server according to e-service templates. Broker Server according to e-service templates. E-service E-service specificationsspecifications are maintained by the Broker Server. are maintained by the Broker Server.

Process model designers specify Process model designers specify e-service requestse-service requests in a in a process model according to e-service templates. process model according to e-service templates.

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Build-time Relationship among the Broker Server, Build-time Relationship among the Broker Server, Service Providers and Process Model DesignerService Providers and Process Model Designer

Broker Server

E-Service Rquests

Process Model Designer

Service Provider

Service

E-Service Adapter

ServiceService

register reference

E-Services

E-Service Specification

E-Service Template

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An Example of E-Service TemplateAn Example of E-Service Template

Operations Name Type

Input Attributes Product_NameModel_NameQuantityUser_Info

StringStringIntUserInfo

Output Attributes Status Status

ProcessOrder

Service Attributes DurationCostShpping_Method

TimeCostString

Business Type: Distributor E-Service: OrderProcessing

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An Example of E-Service ConstraintAn Example of E-Service Constraint

E-Service Constraint E-Service Constraint restricts the kind of data that the requester of an e-restricts the kind of data that the requester of an e-service can provide when the e-service is invoked. service can provide when the e-service is invoked.

Distributor Distributor Worldwide Worldwide which provides the e-service which provides the e-service OrderProcessing OrderProcessing may specify constraints on the operation may specify constraints on the operation Process Order Process Order as follows:as follows:

ATTRIBUTE_CONSTRAINT:ATTRIBUTE_CONSTRAINT:

Product_Name String ENUMERATION [“Computer”] priority[1]Product_Name String ENUMERATION [“Computer”] priority[1]

Model_Name String ANY priority[2]Model_Name String ANY priority[2]

Quantity Integer RANGE [1-1000] priority[3]Quantity Integer RANGE [1-1000] priority[3]

INTER_ATTRIBUTE_CONSTRAINT:INTER_ATTRIBUTE_CONSTRAINT:

Iac1Iac1 Quantity > 500 Quantity > 500 impliesimplies Duration>10 Duration>10

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E-Service RequestE-Service Request

E-service requestsE-service requests in a process model are defined in a process model are defined according to e-service templates.according to e-service templates.

An e-service request contains two parts:An e-service request contains two parts:– Variable mappings of the input/output attributes.Variable mappings of the input/output attributes.

– Constraints on the service attributes.Constraints on the service attributes.

ATTRIBUTE_CONSTRAINT:ATTRIBUTE_CONSTRAINT:Duration int RANGE[0 .. 10] priority[1]Duration int RANGE[0 .. 10] priority[1]

Cost float RANGE[0 .. 1000] priority[2]Cost float RANGE[0 .. 1000] priority[2]

INTER_ATTRIBUTE_CONSTRAINTINTER_ATTRIBUTE_CONSTRAINT

Iac1Iac1: Duration >4 : Duration >4 implies implies Cost < 800Cost < 800

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Constraint-based BrokeringConstraint-based Brokering

An important function of the Broker Server is to do An important function of the Broker Server is to do constraint-based brokering and service provider selection.constraint-based brokering and service provider selection.

ProceduresProcedures– Call Call Constraint Satisfaction Processor (CSP)Constraint Satisfaction Processor (CSP) to match the to match the e-service e-service

request constraintsrequest constraints with the with the e-service constraintse-service constraints in the e-service in the e-service specifications of different service providers.specifications of different service providers.

– Three possible results:Three possible results: None: fail.None: fail. Only one: succeed.Only one: succeed. More than one: call More than one: call Cost Benefit Module (CBM) Cost Benefit Module (CBM) to get the best to get the best

service provider.service provider.

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E-Service Invocation MechanismE-Service Invocation Mechanism

Legacy Application

E-Service Adapter E-Service Adapter

Distributed Object

ISEE Hub

WF EngineBroker Proxy

Local Workflow

SOAP MSG

Internet (HTTP)

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Extension to WPDLExtension to WPDL

Introduction to Introduction to ConnectorConnector Encapsulation of the activity definitionEncapsulation of the activity definition Inclusion of e-service requests in activity definitionsInclusion of e-service requests in activity definitions Inclusion of explicit data flow specificationInclusion of explicit data flow specification Introduction of events and rulesIntroduction of events and rules

– Before-Activity-EventBefore-Activity-Event

– After-Activity-Event After-Activity-Event

– External EventExternal Event

Workflow Events

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Workflow EventsWorkflow Events Workflow Events are automatically generated based on the process Workflow Events are automatically generated based on the process

model name, the activity name, and the input and output data of the model name, the activity name, and the input and output data of the activity.activity.

Synchronous workflow eventSynchronous workflow event– The rules attached to the synchronous workflow events of a process model The rules attached to the synchronous workflow events of a process model

can only be defined by the model designer and by the organizations that can only be defined by the model designer and by the organizations that use the business process model.use the business process model.

– Organization customizationOrganization customization: different organizations defines business rules : different organizations defines business rules attached to the synchronous workflow events to reflect their local business attached to the synchronous workflow events to reflect their local business policies.policies.

– Instance customizationInstance customization: a workflow instance can also trigger a different set : a workflow instance can also trigger a different set of rules when an unexpected event happens.of rules when an unexpected event happens.

Asynchronous workflow events:Asynchronous workflow events:– The organizations in the virtual enterprise can subscribe to the The organizations in the virtual enterprise can subscribe to the

asynchronous workflow events and receive notifications on asynchronous workflow events and receive notifications on some processing milestones of an enacted business process or exceptions.

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Graphical Representation of a Process Model in DWMGraphical Representation of a Process Model in DWM

AE

EE

BE

Activity

Connector

Condition

Before- Activity-Event

After- Activity-Event

External Event

Rule

Transition

Subflow

Data flow

BE

AE

EE

Triggers

Begin-Activity or End-Activity

Block

Legend:

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Activity Definition... Activity Definition... Activity specification

ACTIVITY <activity id>

[DESCRIPTION <description>]

[PERFORMER < participant assignment>]

IN_PARAMETER <input parameter list>

OUT_PARAMETER <output parameter list>

[WF_EVENTS] <workflow event list>

[ACTIVITY_VAR <variable list>]

IMPLEMENTATION <activity body>

END_ACTIVITY

Task items in activity body

– E-service requests

SERVICE <business type name>. <e-service name>SERVICE <business type name>. <e-service name>

INPUTINPUT < <in_attributes mapping>in_attributes mapping>

[OUTPUT[OUTPUT < <out_attributes mapping>]out_attributes mapping>]

CONSTRAINTCONSTRAINT < <constraint definition>constraint definition>

END_SERVICEEND_SERVICE

– Inline code

– External event posting

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PERFORMER specificationPERFORMER specification PERFORMERPERFORMER <business type name> (<performer selection constraint>)<business type name> (<performer selection constraint>)

performer selection constraintperformer selection constraint– CONSTANTCONSTANT

PERFORMER PERFORMER DistributorDistributor (CONSTANT (CONSTANT IBMIBM))

– ANYANYPERFORMER PERFORMER Transportation_AgencyTransportation_Agency (ANY) (ANY)

– SAME_ASSAME_ASPERFORMER PERFORMER DistributorDistributor (SAME_AS (SAME_AS Activity1Activity1))

– VARIABLEVARIABLEPERFORMER PERFORMER ManufacturerManufacturer (VARIABLE (VARIABLE Activity2.bestManufacturerActivity2.bestManufacturer))

...Activity Definition ...Activity Definition

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Sample Activity DefinitionSample Activity DefinitionACTIVITY Shipping

DESCRIPTION “Ship the order to the customer”.IN_PARAMETERS ProductDesc prod_desc, Integer quantity, UserInfo user_infoOUT_PARAMETERS Boolean shipping_statusPERFORMER TransportationAgency (ANY)WF_EVENT async-afterIMPLEMENTATION

 E-SERVICE ShipOrder.InitiateShipping INPUT prod_desc, quantity, user_info OUTPUT shipping_status CONSTRAINT ATTRIBUTE_CONSTRAINT: duration int [0 .. 5] priority[1] END_CONSTRAINTEND_SERVICE

 END_IMPLEMENTATION

END_ACTIVITY

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Dynamic Properties of DWMDynamic Properties of DWM

ActiveActive: Business process may post synchronous and/or : Business process may post synchronous and/or asynchronous events to trigger the processing of business asynchronous events to trigger the processing of business rules.rules.

FlexibleFlexible: The e-service requests specified inside a process : The e-service requests specified inside a process model are bound to suitable service providers during the model are bound to suitable service providers during the enactment of the business process through a dynamic enactment of the business process through a dynamic service binding mechanism.service binding mechanism.

AdaptiveAdaptive: Process models can be easily modified to adapt to : Process models can be easily modified to adapt to the changing business environment. the changing business environment.

CustomizableCustomizable: Organizational customization and instance : Organizational customization and instance customization can be achieved through the customization of customization can be achieved through the customization of business rules attached to synchronous workflow events.business rules attached to synchronous workflow events.

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Sample ScenarioSample Scenario

Order Entry

Check and Adjust Inventory

Acknowledge Purchase Order

Initiate Shipping

Begin

End

Distributor (ANY)

Distributor (SAMEAS A1)

Transportation Agency (ANY)

B ESYNC

AE

ASYNC

AE

A1:

A2:

A4: A5:

AND

AND

Distributor (SAMEAS A1)

ASYNC

T1

T2

T3

T4 T5

T6 T7

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Process Definition Tool

Metadata Manager

Process Models, E-service Constraints,E-service Templates,

Events, Triggers,

Rules

KPMConstraint

GUI

Triggers, Rules, Data Classes, Events

E-Service Request Constraints

Process Models

Runtime WF Structures, Activity Codes,

E-service Templates

Event Server

ETR Server

Install Events

Install Events, Triggers, Rules

WF Code Generator

Process Models

Install Events

Invoke

Invoke

Invoke

Build-time Build-time EnvironmentEnvironment

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Process Definition ToolProcess Definition Tool

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Code Generation ApproachCode Generation Approach

Code GenerationCode Generation approach is used to implement the Workflow Engine. approach is used to implement the Workflow Engine. The Workflow Code Generator is used to process a process model’s The Workflow Code Generator is used to process a process model’s

meta-information and to generate meta-information and to generate run-time workflow structuresrun-time workflow structures and and activity codes.activity codes.

The Workflow Engine uses run-time workflow structures to schedule The Workflow Engine uses run-time workflow structures to schedule the transitions and data flows between activities, blocks, and subflows.the transitions and data flows between activities, blocks, and subflows.

When an activity is scheduled for execution, the Workflow Engine When an activity is scheduled for execution, the Workflow Engine simply loads the corresponding activity code from a run-time simply loads the corresponding activity code from a run-time repository and executes the code directly to perform the specified task repository and executes the code directly to perform the specified task items.items.

Code Generation approach results in a Code Generation approach results in a lightweightlightweight, , efficientefficient, and , and adaptiveadaptive Workflow Engine. Workflow Engine.

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Run-time Workflow StructuresRun-time Workflow Structures

An entity structureAn entity structure provides the necessary information to schedule and execute provides the necessary information to schedule and execute each of the following entities in a process model: activities, blocks, and each of the following entities in a process model: activities, blocks, and subflows. subflows.

A control flow structureA control flow structure is generated for each of the following entities of a is generated for each of the following entities of a process model: activity, subflow, block, connector, and End-Activity. It process model: activity, subflow, block, connector, and End-Activity. It captures the control dependency between the entity and its preceding entities in a captures the control dependency between the entity and its preceding entities in a process model.process model.

– Entity name: The name of the entity of the control flow structure name: The name of the entity of the control flow structure

– Aggregation property: Aggregation property: JOIN connector: same as the aggregation property of the connector (i.e., AND, OR, or JOIN connector: same as the aggregation property of the connector (i.e., AND, OR, or

XOR).XOR). Otherwise, the aggregation property is SIMPLE.Otherwise, the aggregation property is SIMPLE.

– Transition(s):Transition(s): JOIN connector: multiple transitions. JOIN connector: multiple transitions. Otherwise, only one transition. Otherwise, only one transition.

A data flow structureA data flow structure specifies data dependency, i.e., the parameter mapping specifies data dependency, i.e., the parameter mapping information between two entities in a process model. information between two entities in a process model.

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Dynamic Service BindingDynamic Service Binding Get e-services that need to be provided by the same service providerGet e-services that need to be provided by the same service provider

– E-Services inside an activity definitionE-Services inside an activity definition– SAME_ASSAME_AS

Put e-service request constraint and the values of input attributes togetherPut e-service request constraint and the values of input attributes together– Constraint on the service attributes of an e-service Constraint on the service attributes of an e-service

ATTRIBUTE_CONSTRAINT:ATTRIBUTE_CONSTRAINT:duration int RANGE[0 .. 10] priority[1]duration int RANGE[0 .. 10] priority[1]cost float RANGE[0 .. 1000] priority[2]cost float RANGE[0 .. 1000] priority[2]

INTER_ATTRIBUTE_CONSTRAINTINTER_ATTRIBUTE_CONSTRAINT iac1iac1: duration >4 : duration >4 implies implies cost < 800cost < 800

– The values of input parameters of an e-service requestThe values of input parameters of an e-service request

ATTRIBUTE_CONSTRAINT:ATTRIBUTE_CONSTRAINT:Product_Name String EQUAL “Compaq” Priority [1]Product_Name String EQUAL “Compaq” Priority [1]Model_Name String EQUAL “Model_Name String EQUAL “PentiumIII 800” Priority [1]” Priority [1]

Contact the Broker Server to get the proper service provider.Contact the Broker Server to get the proper service provider.

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Activity CodeActivity CodeImport statementsClass processName::activityName{ variable declaration  processName::activityName() // Constructor { [ Get reference of the broker proxy ] /* If there are e-service requests in the activity.*/ [ Get references of the event server and the ETR server ] /* If there are event postings.*/ }  ActivityResult activate(Vector inputValues, String businessType, Hashtable serviceConstraints ) { Initialization of input variables … /* Following statements are for dynamic service binding */ [ Put input attribute values of an e-service to the e-service request constraint ] [ Contact broker proxy to get the service provider’s URL (dynamic service binding) ] … /* Following statements are for an e-service invocation */ [ Generate SOAP request message ] [ Invoke e-service and get SOAP response message ] [ Get the return value from the SOAP response message ] … /* Following statements are for an event posting. */ [ Construct the event object ] [ Post synchronous event to the ETR Server ] [ Post asynchronous event to the Event Server ] … /* For inline code, directly copy it to the activity code. */ [ inline code ] … }

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Workflow Engine ArchitectureWorkflow Engine Architecture

Workflow Scheduler

E-Service Adapter

Initiate Workflow Instance

Activity Codes

Runtime WF Structure

Activity Handler

Service Client

Subflow Scheduler Block Scheduler

E-Service AdapterE-Service Adapter

ETR Server

Event Server

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Run-time Modification to Process ModelRun-time Modification to Process Model

Run-time modifications to a process model is achieved by the modification to the run-time workflow structure.– Delete/Add a Transition

– Delete/Add a Data flow

– Replace an Activity

– Modify Condition

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Summary of Research and ContributionsSummary of Research and Contributions The design of a The design of a Dynamic Workflow Model (DWM)Dynamic Workflow Model (DWM) by extending by extending

WfMC’s WPDL: adding the concepts of events and rules into WfMC’s WPDL: adding the concepts of events and rules into WPDL, introducing the WPDL, introducing the Connector Connector construct, encapsulating activity construct, encapsulating activity definitions, and supporting e-service requests. DWM is active, definitions, and supporting e-service requests. DWM is active, flexible, adaptive, and customizable. flexible, adaptive, and customizable.

The introduction of a constraint-based dynamic service binding mechanism for the enactment of business processes.

The design of an DynaFlow, which is a part of the ISEE information infrastructure for supporting e-business enterprises.

The technique for run-time modifications of the run-time workflow structures to alter the course of executing workflow instances.

How Dynamic?

(1) Constraint-based dynamic service binding

(2) Organizational customization of process model

(3) Instance customization of process model

(4) Run-time modification to process model

(5) Notification of Milestones of the enactment of business processes

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Future WorkFuture Work

Security issuesSecurity issues– Process modelsProcess models

– Workflow eventsWorkflow events

– E-servicesE-services Correctness proof of a process modelCorrectness proof of a process model The assumptions on standardized e-service templates may not be The assumptions on standardized e-service templates may not be

realistic because different organizations may use different ontologies. realistic because different organizations may use different ontologies. Also, the e-services they provide may have different operations and Also, the e-services they provide may have different operations and attributes.attributes.

Further research can be done on e-service composition.Further research can be done on e-service composition.