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1 Workflow Description for Open Hypermedia Systems Sanjay Vivek, David C. De Roure [email protected] Department of Electronics and Computer Science University of Southampton, UK

1 Workflow Description for Open Hypermedia Systems Sanjay Vivek, David C. De Roure [email protected] Department of Electronics and Computer Science

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1

Workflow Description for Open Hypermedia

Systems

Sanjay Vivek, David C. De Roure

[email protected]

Department of Electronics and Computer ScienceUniversity of Southampton, UK

2

Outline

Brief history of third party link services What is workflow? Web Services and OHS Web Services Flow Language(WSFL) and

workflow concepts Roles in OHS Recursive composition Summary and Discussion

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Simple Open Hypermedia architecture

Link database

documents

Note the direction of this arrow!

Separable hyperstructure

4

Documents in native format

Hypermedia Link service

Customised hypermedia documents

Query(before, during or after doc is delivered)

Open Hypermedia as a Link Service

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ProxyDLS

client

Link service

Internet

The ‘Proxy DLS’ is an HTTP proxy that inserts links on-the-fly by querying the link service

Proxy DLS

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resolver

resolver

resolver

resolver

resolverconcurrency

fault tolerance

aggregation

DLS distributed architectureQUERY

Linkbase migration

Resolver

Resolver

Resolver

server

server

LINK DATA

Mobile link resolution agents

API

API

API

API

API

AGENT

Music content-based navigation

Link-enabled Application

LINK

Link ManagerAvailable Links

Interface

FeatureExtractor

FeatureMatching +Retrieval

LinkService

D.L.S.

FeatureAgents

Digital Library

Link Database

Feature Database

Streaming media using RTSP over IPv6

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Current Music IR architecture

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But where does link data come from?

DIY slide - Please label the boxes yourself

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Overview

Introduce workflow support for OHS Expose these OHS components as Web

Services Enable integration and coordination with

Web Services Flow Language (WSFL)

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What is workflow?

Workflow deals with the management, specification, and execution of operations (business processes) in organizations

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IBM

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IBM

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Agent Technology: A Canonical View

Environment

Agent

InteractionsOrganisationalrelationships

Sphere of influenceJennings, CACM

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WSFL and workflow concepts

XML language for the description of Web Services compositions

Essentially a specification to implement a business process model

Uses a workflow engine like the MQSeries Workflow to consume WSFL

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<globalModel name="bookTripNTickets" serviceproviderType="agentType">

<serviceProvider name="travelAgent" serviceProviderType="tio:agentType">

<export> <source portType="tio:tripHandler"

operation="sendItinerary"/> <target portType="tio:tripNTicketHandler"

operation="sendItinerary"/> </export> <export> <source portType="tio:tripHandler"

operation="receiveTripOrder"/> <target portType="tio:tripNTicketHandler"

operation="receiveTripOrder"/> </export> <locator type="..." /> </serviceProvider>

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Web Services and OHS(i)

To simplify the development and integration of distributed hypermedia services over the network

Web services enable you to loosely couple processes

Workflow helps integrate new and existing services

Previous work (Haake) in CSCW context rather than web services

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Web Services and OHS(ii)

An example OHS model consists of the client, a link service, and a linkbase

OHS components are clearly defined and can be described as a Web Service

Workflow helps sequence, coordinate, and manages conversations among Web services

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WSFL and workflow concepts(ii)

Submit QueryCertify Client

TranscodingService

User Profile

Submit QueryWith User Data

Receive Query

Transmit Query

Client Link Service LinkBase

Receive Query

Start

End

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WSFL and workflow concepts(ii) Each box is an activity

and is a WebService Processing logic is

indicated by the directed edges

Control points ensure if certain conditions are met before processing the next activity

Submit QueryCertify Client

TranscodingService

User Profile

Submit QueryWith User Data

Receive Query

Transmit Query

Client Link Service LinkBase

Receive Query

Start

End

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Roles in OHS

Every activity is implemented as a Web Service offered by a Web Service provider

The example OHS Model can be described in WSDL as follows:

<serviceProvider name =”Client” type=”client”/>

<serviceProvider name =”Linkservice” type=”linkservice”/>

<serviceProvider name=”Linkbase” type=”linkbase”/>

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Recursive Composition

Enables service providers to combine services into a single solution

The end user will see the Web Service as a single entity and not as a composite of web services

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Summary and Discussion

Deploy OHS services within a Web Service architecture and the usage of WSFL for coordination and interoperability

Two areas of possible research interest Application Interaction Reliability of services

Should the OHS community be defining “OHP” in web services?