Linking Services and Linked Data

John Domingue

Knowledge Media Institute,

The Open University, UK

Overview

• Linked data introduction– Linked data successes

• Linked Services– Approaches and principles– Technologies supporting Linked Services

• Models: MicroWSMO, WSMO-Lite and the Minimal Service Model• Tools: iServe, SWEET and OmniVoke

• Sample applications– House hunting– Integrating advertising and video in Watch’n’Buy

• Current and future work• Summary

LINKED DATA INTRODUCTION

Semantic Web Stack

RDF = Subject, Property, Value Triples

Triples combine to make Graphs

Linked Data Principles

1. Use URIs as names for things.

2. Use HTTP URIs so that people can look up those names.

3. When someone looks up a URI, provide useful RDF information.

4. Include RDF statements that link to other URIs so that they can discover related things.

Tim Berners-Lee, http://www.w3.org/DesignIssues/LinkedData.html, 2006

Set of best practices for publishing structured data on the Web in accordance with the general architecture of the Web.

LINKED DATA SUCCESSES

BBC Sports

BBC Sports

BBC Sports

www.bbc.co.uk/ontologies/sport

Live Video Streams

I ‘Like’ Casablanca

People, photos, friends and the Web

Google Buys MetaWeb

Freebase Data

Application Portals

Where does my money go?

ASBOrometer

Linked Open Data Cloud

LINKED SERVICES

Linked Data and Services

• Provide a platform for building applications on top of Linked Data

• Connect services and semantic formats within the Web context

• Ease the tasks associated with building applications from online service components

Rise of Web APIs

J. Mosser: “Open APIs: state of the market”, Glue conference 2011

LINKED SERVICES APPROACH AND PRINCIPLES

Linked Services Principles

• Services described as Linked Data– Inputs, outputs, functionality, etc is described using RDF(S) and

using existing vocabularies

• Consume and produce RDF– Applications may contain ‘standard services’ too

• Process layer on top of the Web of Data

TECHNOLOGIES SUPPORTING LINKED SERVICES

MicroWSMO & WSMO-Lite

36

Minimal Service Model

SWEET & SOWERLPML

deployment

Process Editor

Discovery

incl. TG, Optimizer, DTC

SOA4All Process Lifecycle

Service annotation

Process modeling

Process execution

Analysis & Monitoring

incl. BPEL-based execution environment

Invocation

ISERVE SERVICE REPOSITORY

iServe Key Features

• Support for several SWS formalisms– WSMO-Lite, MicroWSMO, SAWSDL, OWL-S

• Supports access via– Web Application - iServe Browser– Read and Write RESTful API– Linked Data principles– SPARQL endpoint– Content negotiation (RDF, HTML)

• Support for hybrid discovery• Integration of social features (tags, comments,

ratings)

iServe Browser

Linked Open Data Cloud

iServe Context

iServe Architecture

SWEET

SWEET Workflow

SWEET: Initial State

Dynamics, APIs and Services / Hands-on SWEET/iServe and WSMT - 47

Input: HTML description of the Web API (local representation of the HTML, which is used as a basis for the annotation process)

Addition of the HTML tags

Current status of the annotation in the form of a tree structure

Identifying Service Properties

Semantic Annotation

SWEET Architecture

OMNIVOKE

OmniVoke Context

OmniVoke Architecture

TYPICAL APPLICATION SCENARIO

SAMPLE APPLICATIONS

Example 1: House Hunting …

… public transport …

… schools

www.tauntonschool.co.uk

Behind the Scenes

Train stations

Bus stops

Schools

Real estate

Public Data and Services

discovery

invocation

publishingService Broker

WATCH’N’BUY

Our Model

Architecture

CURRENT AND FUTURE WORK

ParkJam

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Sharing Human Body ProcessesP

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Cardiovascular Workflow

Internet of ServicesThe Internet of Services allows• the trading of services• the bundling of

services• the automatic offering,

delivery, and execution

© SAP 2010 / Page 78

ServiceAggregator

ServiceHoster

ServiceProvider

ServiceGateway

ServiceBroker

ServiceChannel Maker

The Internet of Services – Unified Service Description Language (USDL)

See also: http://www.internet-of-services.de/index.php?id=24

Service Transformation stands for a value-driven, smooth and effective provision of services along the Global Service Delivery Supply Chain

Service Transformation implies that Services are being Described considering business, operational and legal requirements Maintained, extended and assembled where needed Applying a common notation named USDL

USDL http://www.internet-of-services.com/

Linked-USDL http://www.linked-usdl.org/

Summary• Linked data now a mainstream mechanism for sharing

data on the Web• Now a requirement for application development support

– Especially within emerging Linked Data portals

• Linked services– Services which consume and produce linked data – Described as Linked Data– Approaches and principles

• Technologies supporting Linked Services• Models: MicroWSMO, WSMO-Lite and the Minimal Service Model• Tools: iServe, SWEET, OmniVoke….

• Validation of approach through diverse application scenarios

• Linked-USDL for services at the business level

Acknowledgements

• BBC slides adapted from Jem Rayfield http://www.slideshare.net/JemRayfield/mark-logic-usergroup2012

• Internet of Services adapted from SAP including Axel Fasse http://www.slideshare.net/drleidig/linked-usdl-at-the-fiware-architects-weeks-in-madrid

• Chris Bizer, Jacek Kopecky, Ning Li, Dong Liu, Maria Maleshkova, Carlos Pedrinaci

• Funded by the SOA4All, NoTube, PlanetData and VPH Share projects

THANKSMore details at: iserve.kmi.open.ac.uk