Tutorial on Semantic Digital Libraries (ESWC'2007)

Tutorial – Semantic Digital Libraries

- Introduction -

Sebastian R. Kruk, Bernhard Haslhofer,

Philipp Nußbaumer, Sandy Payette, Tomasz Woroniecki

Tutorial overview

• Who we are– Sebastian R. Kruk, DERI Galway – Ireland

– Bernhard Haslhofer, University of Vienna - Austria

– Phillip Nußbaumer, Research Studios - Austria

– Sandy Payette, Cornell University – USA

– Tomasz Woroniecki, DERI Galway – Ireland

• Today we want to– give you a brief introduction to the Semantic Web, and show how SW is related to

digital libraries

– present existing semantic digital library systems

– discuss the current problems and future directions of semantic digital libraries and get feedback from you

• After this tutorial you will know– what is the semantic digital library system

– existing solutions in various degrees of detail

– how to run semantic digital library solutionson your machine

Tutorial Schedule

9:00 - 9:45 Introduction to Semantic Digital Libraries

9:45 – 10:30 Existing solutions - JeromeDL

10:30 – 11:00 Coffee break

11:00 - 12:15 Existing Semantic Digital Libraries solutions

12:15 – 12:30 Comparison and the future of SemDL

12:30 – 14:00 Lunch break

14:00 – 15:30 Hands-on session (part I)

15:30 – 16:00 Coffee break

16:00 – 16:45 Hands-on session (part II)

16:45 - 17:30 Conclusions, discussion

Outline

Introduction to Semantic Web

Semantic Digital Libraries

The Semantic Web – A Brief Introduction

• Current Web vs. Semantic Web?– An extension of the current Web in which information is given well-defined

meaning, better enabling computers and people to work in cooperation. [Tim Berners-Lee]

– Current Web was designed for humans, and there is little information usable for machines

• Was the Web meant to be more?– Objects with well defined attributes as opposed to untyped hyperlinks

between Internet resources

– A network of relationships amongst named objects, yielding unified information management tasks

• What do you mean by “Semantic”?– the semantics of something is the meaning of something

– Semantic Web is able to describe things in a way that computers can understand

YouAre

Where are we in the “Semantic Web layer cake”?

The challenge for the Semantic Web– The Semantic Web can’t work all by itself– For example, it is not very likely that you will be able to sell

your car just by putting your RDF file on the Web– Need society-scale applications: Semantic Web agents and/or

services, consumers and processors for semantic data, more advanced collaborative applications

The Semantic Web – What is RDF ?

Describing things on the Semantic Web– RDF (Resource Description Framework)

• a data format for describing information and resources,

• the fundamental data model for the Semantic Web

– Using RDF, we can describe relationships between things like:

• A is a part of B or

• Y is a member of Z

• and their properties (size, weight, age, price…) in a machine-understandable format where each thing has a

– RDF graph-based model delivers straightforward machine processing

– Putting information into RDF files makes it possible for “scutters” or RDF crawlers to search, discover, pick up, collect, analyse and process information from the Web

The Semantic Web – What is RDF ?

A simple RDF example– Statement:

“Stefan Decker is the creator of the resource (web page) http://www.stefandecker.org”

– Structure:

Resource (subject) http://www.stefandecker.org

Property (predicate) http://purl.org/dc/elements/1.1/creator

Value (object) “Stefan Decker”– Directed graph:

http://www.stefandecker.orgdc:creator Stefan Decker

The Semantic Web – How RDF can help us?

How RDF can help us?• identify objects

• establish relationships

• express a new relationship just add a new RDF statement

• integrate information from different sources copy all the RDF data together

• RDF allows many points of view

• What is an Ontology?„An ontology is a specification of a conceptualization.“

Tom Gruber, 1993

• Ontologies are social contracts– Agreed, explicit semantics

– Understandable to outsiders

– (Often) derived in a community process

• Ontology markup and representation languages:– RDF and RDF Schema

– OWL

– Other: DAML+OIL, EER, UML, Topic Maps, MOF, XML Schemas

The Semantic Web – Ontologies and Schemata

• Defines small vocabulary for RDF: – Class, subClassOf, type

– Property, subPropertyOf

– domain, range

• Vocabulary can be used to define other vocabularies for your application domain

The Semantic Web – RDF Schema

Person

Student Researcher

subClassOfsubClassOf

hasSuperVisordomain range

hasSuperVisor

OWL – The Web Ontology Language

Owl took Christopher Robin’s notice from Rabbit and looked at it nervously. He could spell his own name WOL, and he could spell Tuesday so that you knew it wasn’t Wednesday, and he could read quite comfortably when you weren’t looking over his shoulder and saying "Well?" all the time...

• provides a vocabulary for defining classes, their properties and their relationships among classes.

The Semantic Web – OWL

owl:disjointWith

Animal

Herbivore

Carnivore

Omnivore

• Based on Description Logics

• OWL is a W3C Recommendation

The Semantic Web – Applications

• Semantic Web cannot be and is not only a set of recommendations

• Semantic Web is becoming reality by applications that support it and are based on it

• Enabling technologies:– RDF Storages: Sesame, Jena, YARS– Reasoners: KAON, Racer – Editors: Protege, SWOOP, MarcOnt Portal

• End-User applications:– Semantic wikis: Makna, SemperWiki– Semantic blogs– Semantic digital libraries

Outline

Introduction to Semantic Web

Semantic Digital Libraries

What is a Semantic Digital Library?

Semantic digital libraries– integrate information based on different

metadata, e.g.: resources, user profiles, bookmarks, taxonomies – high quality semantics = highly and meaningfully connected information

– provide interoperability with other systems (not only digital libraries) on either metadata or communication level or both – RDF as common denominator between digital libraries and other services

– delivering more robust, user friendly and adaptable search and browsing interfaces empowered by semantics

Old days of hard-copy books

• Library:– Archive (storage space)

– Bibliographic cards (metadata)

– Librarian (interface)

• Pros:– Someone to talk to, to understand us, to explain, help in searching

• Cons:– Based on physical location

– Libraries are not connected – we have to visit every place

Yesterday of digital books

• Digital library– Database and archive (storage)

– Digital bibliographic descriptions (metadata)

– Full-text search (interface)

• Pros:– Content accessible online

– Federations of libraries – visit less places

• Cons:– Lonely user - no one to talk to, we need to find the right keywords,

what if we do not know them (“man without an ear” paintings example)

– Still many problems with interconnecting (different) libraries

Today of interconnected content

• Semantic Digital Libraries– Database and archive (storage)

– Semantic bibliographic description (interconnected metadata)

– Search and browsing on ontologies (interface)

• Pros:– Search and browsing based on semantics can help in substituting

the librarian

– It is easier to interconnect heterogeneous libraries (RDF as common denominator)

• Cons:– Semantics created from legacy formats – still hard to capture by

most of average users

Tomorrow of social media

• Social Semantic Digital Libraries– Database and archive (storage)

– Bibliographic descriptions with annotations provided by users (metadata)

– Collaborative search and browsing (interface)

• Pros:– Users contribute to the classification process

– Users can understand community driven annotations

– Users enhance digital content using blogs, wikis on the side

• Cons:– Not everyone is convinced

How are Semantic Digital Libraries different?

Semantic digital libraries extend digital libraries by– describing and exposing its resources in a machine

‘understandable’ way– resources can be

• contents, digital artefacts• organization of objects (e.g. collections)• users, user communities• controlled vocabularies, thesauri,

taxonomies– expose the semantics of their metadata

in terms of an ontology• defined using a formal language

– deliver mediation services for communication with other systems

Semantic Web Technologies for Digital Libraries?

Metadata is the key concept• the Web does not have metadata

– the idea of a Semantic Web is nice but difficult to implement

• many digital libraries do have metadata in place• we simply must make them available in a machine

understandable format• the Semantic Web provides the format: RDF

Semantic Web Technologies for Digital Libraries?

Knowledge in bibliographic records• Digital Libraries already have controlled vocabularies,

taxonomies or even ontologies in place • the challenge is to model this knowledge in a machine

understandable way• the Semantic Web provides ontology languages:

– RDF Schema– OWL– SKOS

A Sample Bibliographic Record

Vincent van Gogh; painter: Gogh, Vincent van (Dutch painter, 1853-1890)

Creation-Creator/Role

J. Paul Getty MuseumCurrent Location-Repository Name

irises, nature, soil, etc.Subject-Matter

1889, earliest: 1889, latest: 1889Creation-Date

IrisesTitle

paintingsObject/Work type

PaintingsClassification

College Art Association, Inc.

Terms taken from Controlled Vocabularies

Knowledge Organization Systems

• tools that present the organized interpretation of knowledge structures

• semantic tools - meaning of words and other symbols as well as

(semantic) relations between symbols and concept

• organize information and promote knowledge management

• Examples:

– classification and categorization schemata (organize materials at a general

level)

– subject headings (provide more detailed access)

– authority files (control variant versions of key information such as

geographic names and personal names)

– highly structured vocabularies, such as thesauri

– traditional schemes, such as semantic networks and ontologies

Taxonomy of Knowledge Organization Systems

• Term Lists

– Authority files (FOAF)

– Glossaries

– Dictionaries

– Gazetteers

• Classifications and Categories (DMoz)

– Subject headings

– Classification schemes

– Taxonomies

– Categorization Schemes.

• Relationship Lists

– Thesauri (WordNet, MeSH)

– Semantic networks

– Ontologies (Hodge, 2000)

Understanding Knowledge Organization Systems

• controlled vocabulary - a list of terms that have been enumerated explicitly

• taxonomy - a collection of controlled vocabulary terms organized into a

hierarchical structure.

• formal ontology – a controlled vocabulary expressed in an ontology

representation language. This language has a grammar for using vocabulary

terms to express something meaningful within a specified domain of interest.

• meta-model - an explicit model of the constructs and rules needed to build

specific models within a domain of interest. A valid meta-model is an ontology,

but not all ontologies are modeled explicitly as meta-models.

– as a set of building blocks and rules used to build models

– as a model of a domain of interest, and

– as an instance of another model.

Simple Knowledge Organization Systems (SKOS)

• basic structure and content of concept schemes such as

– thesauri,

– classification schemes,

– subject heading lists,

– taxonomies,

– 'folksonomies',

– other types of controlled vocabulary

• core concepts:

– narrower and broader

– isSubjectOf and subject; isPrimarySubjectOf and primarySubject

– member and Collection; memberList and OrderedCollection

– related and semanticRelation

– note, definition; altLabel and prefLabel; symbol and altSymbol

Benefits of Semantic Digital Libraries

Problems of today’s libraries • rapidly growing islands of highly organized information

– How to find things in a growing information space?

• is it enough to have a full-text index (à la Google)?

• typical “end-users” versus “expert users”

• converging digital library systems– e.g. uniform access to Europe’s digital libraries and cultural heritage

Benefits of Semantic Digital Libraries

The two main benefits of Semantic Digital Libraries• new search paradigms for the information space

– Ontology-based search / facet search– Community-enabled browsing

• providing interoperability on the data level– integrating metadata from various heterogeneous sources– Interconnecting different digital library systems

Searching the Sample Bibliographic Record

Vincent van Gogh; painter: Gogh, Vincent van (Dutch painter, 1853-1890)

Creation-Creator/Role

J. Paul Getty MuseumCurrent Location-Repository Name

irises, nature, soil, etc.Subject-Matter

1889, earliest: 1889, latest: 1889

Creation-Date

IrisesTitle

paintingsObject/Work type

PaintingsClassification

College Art Association, Inc.

• Full-text search– “Paintings” AND “Van Gogh”

AND “flowers” no result

• Semantic query– if the knowledge that “irises”

are “flowers” is modeled in an ontology (e.g. subclass-hierarchy)

– we can query for all “Paintings” by “Van Gogh” with subject “flowers” and retrieve also the picture with subject “irises”

Semantic Digital Libraries and Existing DL Systems

• how to handle the legacy (meta-)data problem • lifting existing (meta-)data to a semantic level

– simple solutions like MARC21 DublinCore– complex ontologies like MarcOnt Ontology for capturing concepts

from different standards

• legacy libraries expose their metadata via well established protocols - the metadata can be imported into semantic DLs

• semantic DLs can play a role of integration champions in the information retrieval process in heterogeneous networks:– OAI-PMH– Z39.50– Dienst

Application Areas for Semantic Web Technologies

• Thesauri & Controlled Vocabularies– qualified DublinCore

– DMoz, DDC-based taxonomies

– SKOS, WordNet and other thesauri

• Schema Mappings / Crosswalks– MarcOnt Ontology – aims to cover concepts from MARC21, BibTeX and

DublinCore

– MarcOnt Mediation Services – an open mediation framework between common legacy metadata standards

• Metadata Integration– RDF as a common data model for integrating metadata from various

autonomous and heterogeneous data sources

– OWL for modeling the data source’s semantics

– SPARQL as a common query language

Semantic DL as Evolving Knowledge Space

• In state-of-the-art digital libraries users are consumers– Retrieve contents based on available bibliographic records

• Recent trends: user communities– Connetea– Flickr

• In Semantic digital libraries users are contributers as well– Tagging (Web 2.0)– Social Semantic Collaborative Filtering– Annotations

• Semantic Digital libraries enforce the transition from a static information to a dynamic (collaborative) knowledge space

Existing Semantic Digital Library Systems

• JeromeDL– a social semantic digital library makes use of Semantic Web

and Social Networking technologies to enhance both interoperability and usability

• BRICKS– aims at establishing the organizational and technological

foundations for a digital library network in order to share knowledge and resources in the cultural heritage domain.

• FEDORA– delivers flexible service-oriented architecture to managing

and delivering content in the form of digital objects

• SIMILE– extends and laverages DSpace, seeking to enhance

interoperability among digital assets, schemata, metadata, and services

- Existing Semantic Digital Libraries Solutions -

Existing Semantic Digital Library Systems

• JeromeDL– a social semantic digital library makes use of Semantic Web

and Social Networking technologies to enhance both interoperability and usability

• BRICKS– aims at establishing the organizational and technological

foundations for a digital library network in order to share knowledge and resources in the cultural heritage domain.

• FEDORA– delivers flexible service-oriented architecture to managing

and delivering content in the form of digital objects

• SIMILE– extends and laverages DSpace, seeking to enhance

interoperability among digital assets, schemata, metadata, and services

Tutorial 7 – Semantic Digital Libraries

- Existing Semantic Digital Libraries Solutions –

JeromeDL

Sebastian R. Kruk, Tomasz Woroniecki

Outline

JeromeDL - Motivation and Overview

JeromeDL - Architecture and Ontologies

JeromeDL - Semantic Services

JeromeDL - Social Services

JeromeDL - Semantics in Use

JeromeDL - Introduction

• Joint effort of DERI, National University of Ireland, Galway

and Gdansk University of Technology (GUT)

• Distributed under BSD Open Source license

• Digital library build on semantic web technologies to answer

requirements from: librarians, scientists and everyone.

Motivation

• How to integrate and search information from different bibliographic sources?

• How to share and interconnect knowledge among people?

JeromeDL – Motivations Use Cases

• Librarians:– support for rich metadata (MARC21) in uploading resources,

accessing bibliographic information and searching

– persistent identifiers

• Scientists: – easy publishing (designed as a institute/university digital library)

– creating hierarchical networks of digital libraries

– support for accessing, sharing and searching using bibliography

metadata (BibTeX)

• Everyone:– simple search (incl. natural language queries)

– community-aware information sharing and browsing,

– support for interationalization

JeromeDL - Motivations

• Support for different kinds of bibliographic medatata, like:

DublinCore, BibTeX and MARC21 at the same time.

– Making use of existing rich sources of bibliographic descriptions (like

MARC21) created by human.

• Supporting users and communities:

– users have control over their profile information;

– community-aware profiles are integrated with bibliographic

descriptions

– support for community generated knowledge

• Delivering communication between instances:

– P2P mode for searching and users authentication

– Hierarchical mode for browsing

Outline

JeromeDL – Architecture

• Resources and

annotations repository

• Middleware:– query processing

– community space

– resources management

• User interface agents:

• Communication to the

outside world

• Administrative interface

Bibliographic Description in JeromeDL

<?xml version="1.0" encoding="UTF-8" ?><rdf:Description rdf:about="http://...id=828374765"><dc:title>JeromeDL - Adding Semantic Web Technologies to DLs</dc:title><dc:creator>Sebastian Kruk</dc:creator><dc:description>In recent years...</dc:description></rdf:Description>

01450cas 922004331i 450000100...019c19329999gw qr|p| ||||0 |0ger | a0044-2992 9a200412140219bVLOADc200404071525dvkulc200310071018dvbjc200303101205dkopumky200209211341zVLOAD aGD U/MPcGD U/MPdGD U/MFdGD U/KKsdWR O/EJ0 ager1 aZ. Kunstgesch. 0aZeitschrift für Kunstgeschichte00aZeitschrift für Kunstgeschichte.18aZfK aMünchen ;aBerlin :bDeutscher Kunstverlag,c1932-. c26-29 cm. aKwart.0 a1 Bd. (Juni 1932)-. aOpis na podst.: LCC. aW 1932 założycielami czasopisma byli Wilhelm Waetzoldt i Ernst Gall....

These all can be represented in RDFThese all can be represented in RDF@InProceedings { jeromedexa2005, author = "Sebastian Ryszard Kruk and ... ", title = "{JeromeDL - Adding Semantic ...}", booktitle = "{In Proceedings to DEXA 2005}", year = 2005}

Structure ontology in JeromeDL

Bibliographic (MarcOnt) Ontology in JeromeDL

Community-aware (FOAFRealm) ontology

Ontologies in JeromeDL

Metadata and Services in JeromeDL

Outline

Semantic Metadata and Services

MarcOnt Initiative – Overview

Motivation:

• Provide set of tools for

collaborative ontology

development

MarcOnt Initiative goals:

• Create a framework for collaborative ontology improvement (E-learning)

• Provide domain experts with tools to share their knowledge

• Offer tools for data mediation between different data formats

MarcOnt Portal and MarcOnt Ontology

Sugested Poposals

Initial Ontology

Proposal discussion

Proposal anotations

Proposal votingProposal autopromoting

Versioning

Next RevisionMarcOnt Portal

MarcOnt Ontology:

Central point of MarcOnt Initiative

Translation and mediation format

Continuos collaborative ontology

improvement

Knowledge from the domain experts

MarcOnt Portal (source of

knowledge):

• Suggestions

• Annotations

• Versioning

• Ontology editor

MarcOnt Mediation Services for Legacy Metadata

MarcOnt OntologyMarcOnt RDF

MARC21 RDF

MARC21 XML

MARC21

Dublin Core RDF

Dublin Core XML

Dublin Core

New format RDF

New format XML

New format

Format translation

RDF Translator

Format co-operation

MarcOnt Mediation Services

Browsing the data graph – why?

• The search does not end on a (long) list of results

• The results are not a list (!) but a graph

• „Lost in hyperspace”

• A need for unified UI and services for filter/narrow and

browse/expand services

• Share browsing experience – navigate collaboratively

Browsing the data graph – how?

• Defines REST access to services and their composition

• Basic services: access, search, filter, similar, browse,

combine

• Meta services: RDF serialization, subscription channels,

service ID generation,

• Context services: manage contexts, manage service

calls/compositions in the context, lists contexts

• Statistics services: properties, values,

tokens

Browsing the data graph

• JeromeDL exploits interconnected data

Browsing the data graph

• … to allow browsing

Outline

Semantic Metadata and Services

Social Services in JeromeDL

• Involve users into sharing knowledge

– Blogs – comments and discussions about documents and

resources

– Tagging – collaborative classification

– Wikis – collaboratively edited additional descriptions, such as

summaries and interesting facts

• Preserve knowledge for future use

– Users can learn from experience of others instantly

– Recommend new, interesting resources based on users’ profiles

FOAF - Describing Social Networks

• FOAF - Stands for Friend-of-a-Friend

• Defines properties for a person (but it does not have to be a

person, can be an “agent”)

• Does not only have to contain one person per file

• Can build a network of people with foaf:knows links

• FOAF can be easily extended to meet requirements, as in

the case of FOAFRealm for identity management…

Identity management with FOAFRealm

• Identity defined with extended FOAF

metadata

• Policies expressed by social networking – Distance between owner and requester

– Friendship level between owner and requester,

calculated across digraph of social network

• Support for single registration and sign on

• Distributed identity management with

HyperCuP (“D-FOAF”)• FOAFRealm is currently implemented as a plugin for Tomcat

(Realm/Valve implementation), with PHP and .NET versions

coming soon

Social Semantic Collaborative Filtering

• Why?– The bottom-line of acquiring knowledge: informal communication

(“word of mouth”)

• How?– Everyone classifies (filters) the information in bookmark folders (user-

oriented taxonomy)

– Peers share (collaborate over) the information (community-driven taxonomy)

• Result?– Knowledge “flows“ from the expert

through the social network to the user

– System amass a lot of information on user/community profile (context)

• Problems?– The horizon of a social network (2-3 degrees of separation)

– How to handle fine-grained information (blogs, wikis, etc.)

• Solutions? – Inference engine to suggest knowledge from the outskirts of the

social network

– Support for SIOC metadata:

• SIOC browser in SSCF

• Annotations and evaluations of “local” resources

What is Social Semantic Collaborative Filtering?

• Goal: to enhance individual bookmarks with shared knowledge within a community

• Users annotate catalogues of bookmarks with semantic information taken from DMoz or WordNet vocabularies

• Catalogs can include (transclusion) friend's catalogues

• Access to catalogues can be restricted with social networking-based polices

• SSCF delivers:– Community-oriented, semantically-rich taxonomies

– Information about a user's interest

– Flows of expertise from the domain expert

– Recommendations based on users previous actions

– Support for SIOC metadata

foaf:knows

xfoaf:include

xfoaf:bookmark

Social Networks in Digital Libraries

Resource

xfoaf:Annotation

user_C

creator_B

foaf:knows

marcont:hasCreator

creator_A

foaf:knows

xfoaf:Directory

user_D

xfoaf:owns

xfoaf:linksTo

xfoaf:isIn

Support for

online communities

in SSCF

Support for

online communities

in SSCF

Outline

JeromeDL – Delivering Semantic Content

• Providing semantic annotations during uploading process:

– open module for handling any taxonomies

– keywords based on WordNet and free tagging

– defining structure of resources in the JeromeDL ontology

• Lifting legacy metadata to MarcOnt ontology

• Community maintained annotations

– social semantic collaborative filtering

– semantic descriptions based on the FOAF metadata

Annotating Library Resources

JeromeDL – Semantic Information In Use

• Searching:– Keyword-based search with semantic query expansion

– Semantic search:

• Direct RDF quering

• Natural language templates

• Browsing– Exibit

– MultiBeeBrowse

• Sharing:– Social Semantic Collaborative Filtering

– Semantically Interlinked Online Communities

• Heterogeneous communication:– Bibster, A9, OAI-PMH

Exposing Semantic Annotations

Filtering Resources in JeromeDL

Sharing Knowledge with SSCF

Information Retrieval in JeromeDL

Fulltext Index

StructureRepository

MarcOntRepository

Resources’Content

FOAFRealmRepository

(typed)keywords

RDF & NLQuery

OpenSearchRSS

collaborativefiltering

localinterface

distributedinterface

types translation

semantic queryexpansion

RDF Repositories Secure Snapshot

Networks of Digital Libraries

• ELP (Extensible Library Protocol) implementation

– communication within JeromeDL network

– adapters for communication with other networks

• D-FOAF integration (distributed user profile management)

– single sign on and single registration within D-FOAF network

• HyperCuP integration (scalable P2P network)

• Independent ELP network entry point:

http://search.jeromedl.org/

BRICKS

Bernhard Haslhofer

University of Vienna

Austria

Philipp Nußbaumer

Research Studios

Austria

Outline

BRICKS Overview

BRICKS Components

BRICKS Applications

What is BRICKS?

• A software infrastructure for building digital library networks

– Transparent access to distributed resources

– Multilinguality– Easy installation & maintainance

• A set of end-user applications– Network & content management– Web 2.0 tagging/annotations– Domain specific applications

• A business model– Open source, platform independent– Low cost infrastructure– User communities sustainability

BRICKS Architecture

• A decentralized P2P network– Avoid central coordination

– Highly Scalable, increased reliability

– Minimized maintainance costs

• Each P2P Node is a set of SOA components– Web Service interface

– Platform independent

– Flexible composition

• Components for– Storing, accessing and protecting digital objects

– (Semantic) search & browsing

– P2P commmunication

Workstation

BNodeEMF

Workstation

BNodeAustrian Library

BNodeStudio Azzuro

WorkstationUser

FhG IPSIRequest

RequestRequest

Request

Accessing Data

A Look into a BNode

BNode{

Outline

BRICKS Overview

BRICKS Components

BRICKS Applications

Collection Manager

• Single access point for all content and metadata related operations (local and remote)

• Physical Collection– Similar to folder/directory hierarchy in a file system

– Bound to a single BNode

– Each digital content object belongs to exactly one collection

• Logical Collection– Virtual folder for organizing content items independent of their physical location

– Links to content items from various physical collections on different BNodes

– A content item might belong to many of them

• Stored Query similar to database views

Content Manager

• Two ways to handle content in BRICKS

– Stored locally at site of a member party, accessed via URL

– Stored within BRICKS

• Based on Java Content Repository (JCR)

• Provides a meta-content model

– Re-use of existing content models

– Use standard models

Metadata Manager

• Metadata descriptions RDF– Suitable for any application scenario– Express relationships between

objects– React to changes without changing

the model

• Schema defintions OWL– No fixed schema– Extensible (e.g. Application profiles)– Semantic concepts instead of

schematic strucutures

• SPARQL– Metadata queries over ontology

concepts– Queries for graph patterns

System Core

Storage (Jena)

Data Transformation

Schema Manager

Metadata Manager

Metadata Record

RDF/XML

Web Service

API (WSDL)

dc.xsl vra.xsl xyz.xsl

OAI-PMH Server

OAI-PMH Harvester

DCVRA xyz

mapping mapping

RDB File-DB

Query Adapter

Security Manager

• Transparently invoked by the Framework– any service call is checked

• Context-aware policies based on RBAC (via XACML rules)– supporting Roles, Groups, at DLObject level

• Permission declaration through Javadoc @tags

• Federated identity is managed through an adapted version of OpenSAML

• Reputation-based Trust calculation integrated

• Web-based GUI for security configuration

Digital Rights Management

• DRM Component– Support for licenses based on MPEG-21 REL license declaration standard

– Generic API for the integration of commercial DRM systems

• Watermarking– Open-source watermarking tool for images

– Other tools can be integrated

• BRICKS Store web application for commercial content

• Creative Commons support for other content in BRICKS

Outline

BRICKS Overview

BRICKS Components

BRICKS Applications

Application: BRICKS Workspace

• What does it demonstrate?– A web application (thin client) accessing BRICKS Foundation services– Web 2.0 image

annotations– Reference application

• Primary customers– General end-users (citizens)– Application developers

• Technology– Struts based interface to

the BCH

Application: BRICKS Desktop

• What does it demonstrate?– A rich client application accessing BRICKS foundation services– Direct access to the BCHN

• Primary customers– Expert end-users

(researchers, educators)– Application developers

• Technology– Eclipse based rich

client interface

Application: Annotation Tool

• What does it demonstrate?– Tool which allows end-users to annotate images– Creation of annotation threads– Supervised Annotations

• Primary customers– End-users– Institutions with large

image collections

• Technology– Web Application

Application: Online Exhibition Authoring Tool

• What does it demonstrate?– Creating and publishing online exhibitions

using contents that is availablein the BRICKS network

• Primary customers?– Expert end-users

(curators)

• Technology– Web Application

Application: Archeological Finds Identifier

• What does it demonstrate?– A web application for comparing findings (e.g. ancient coins) with objects in

reference collections – Application of complex

domain ontology (CIDOC-CRM)– Map visualization of GIS-Metadata

• Primary customers?– Museum curators, archaeologists,

students, amateurs,

• Technology– Struts based interface

References

• BRICKS Community Web Site– http://www.brickscommunity.org/

– Main Contact: silvia.boi@metaware.it

• Related (de-facto) standards– Resource Description Framework

(RDF)• http://www.w3.org/TR/rdf-primer/

– OWL Web Ontology Language (OWL)

• http://www.w3.org/TR/owl-guide/

– SPARQL• http://www.w3.org/TR/rdf-sparql-query/

– Java Content Repository (JCR)• http://www.jcp.org/en/jsr/detail?id=170

• Tools and Libraries– Jackrabbit

• http://jackrabbit.apache.org/– Jena Semantic Web

Framework• http://jena.sourceforge.net/

Fedora

Sandy Payette

Director, Fedora Project

Cornell University

Outline

Fedora

Examples: PLoS ONE and National Science Digital Library

Scholarly and Scientific Workbenches

“Web 2.0” Collaborative Repositories Museum Exhibits with Lesson Plans

Fedora Semantic Digital Libraries enable …

DataData

Annotation

Article

Linking Data and Publications

blog and wiki

The Fedora Project

• Fedora– Flexible– Extensible – Digital – Object– Repository– Architecture

• History– Cornell Research (1997-2002)

– DARPA and NSF-funded research and reference implementations– Distributed, Interoperable Repositories (experiments with CNRI)

– Open Source Project (2002-present)– Andrew W. Mellon Foundation (2002-2009)– Joint development by Cornell University and University of Virginia– Transitioning into non-profit organization (Fedora Commons 501c3)

Arts and Humanities

Sciences

Education

Fedora - Technology Integration

Semantic

Repository

Enterprise Preservation

• Information Networks• Contextualization• Relationships• Query• Inference

• Workflow• Messaging• Transactions• Replication

• Digital Objects• Manage• Access• Versioning• Storage

• Integrity Check• Monitoring• Alerting• Migration

Fedora Digital Objects• Flexible object model can support

– Documents, articles, journals

– Electronic Scholarly Texts

– Digital Images

– Complex multimedia publications

– Datasets

– Metadata

– Learning objects

– More…

• Create “networks” of objects using RDF

– Define object relationships and other properties via RDF

– Collection/member; part/whole; etc.

RDF in the Fedora Digital Object Model

Motivations: Fedora and Semantic Technologies

• A natural model for exposing repository as network of objects– Object-to-object relationships– Relationships to external entities– Query the graph; traversal to discover related stuff

• Indexing based on generalizable data model– Graph-based data model is a common reduction– Avoid fixed schema problems and metadata mud wrestling

• Extensible enrichment of object descriptions– Keep overlaying statements from multiple ontologies– Organic evolution

• Powerful queries and inference for repository management– Transitive relationships among objects– Dependency analysis; – Detection/Extraction of sub-graphs– Provenance of disseminations

Digital Objects contain their RDF assertions

• Assert relationships from Fedora base ontology– Collection – member– Whole – part– Equivalence– Description Of– More…

– Assert relationships/properties from community ontologies– isAnnotationOf– isRecommendedBy– isCertifiedBy– More ….

Example:Digital Objects with “compositional semantics”

Use Case: scholarly objects and annotation in the humanities

S erv ice

hasPartD iagram

hasP artL ette rannotationOf

P ID -11P ID -3

P ID -1P ID -10

providesC ontex t

P ID -2

am azo n e-co m m erce

musuem and library objects

commercial web content

scholarly objects

URI-100

xx:recommends

URI-55 yy:certifies

3 Objects – 3 RDF “Relationships” Datastreams

<rdf:Description rdf:about="info:fedora/uva:pid-11> <ais:annotationOf rdf:resource=“info:fedora/uva:pid-3”/></rdf:Description>

</rdf:RDF>

<rdf:Description rdf:about="info:fedora/uva:pid-3"> <uva:hasPartLetter rdf:resource="info:fedora/uva:pid-2"/>

<uva:hasPartDiagram rdf:resource="info:fedora/uva:pid-1"/></rdf:Description>

</rdf:RDF>

<rdf:Description rdf:about="info:fedora/uva:pid-10> <ais:providesContextFor rdf:resource=“info:fedora/uva:pid-3”/></rdf:Description>

</rdf:RDF>

• NOT the core object store - RI is a graph-based index of the repository

• Automatic, incremental indexing into triplestore

• Search/query the repository via Fedora RI Query Interface

Fedora RDF-based Resource Index (RI)

RDF Index of Repository

RDF datastream

Fedora object properties

DC datastream

Digital Object Store

RI Graph - view 1 (abbreviated) …

RI Graph - view 2 (abbreviated) …

RI Implementation: The Triplestore Challenge

• Scalability• Few triplestores perform well for 100M+ triples• Kowari – we tested to 180M triples• MPTStore – we tested to 250M triples

• Performance• Jena - easy to get out of memory• Sesame Native - slow for complex queries • Kowari

• Fast queries and full-featured query language (iTQL)• Instability and corruption problems

• MPTStore• Very fast for SPO queries (limited support for complex queries)• Add/modify significantly faster than Kowari

• Mulgara• Fork of Kowari; complex queries; models; inference• Major bug fixes to fix stability and corruption problems• XA2 transactions• Claims support for billions of triples

Fedora Repository – Notable Features

• Generic Digital Object Model

• Automatic content versioning and audit trail

• Web Service Interfaces (REST and SOAP)

• Authentication

• Authorization– Flexible fine-grained policy enforcement

– Built-in support for Extensible Access Control Markup Language (XACML)

• RDF– Each object contains its own RDF assertions

– Repository-wide index of all object (RDF triplestore)

• Self-healing – rebuild repository via digital object source files

Outline

FEDORA

Examples: PLoS ONE and National Science Digital Library

PLoS ONE and Topaz

Open Access Publishing and Collaboration

NSDL: Semantic Digital Library Architecture

What is NSDL committed to?

– NSDL 2.0 as a platform for a collaborative,

contributory semantic digital library

– Supporting communities across the full range of

science, technology, engineering and mathematics

research, learning and education

– Supporting the creation of context around library

resources to enhance discovery, use, and

understanding

NSDL Semantic Digital Library

repository requirements

• Supports storing both content and

metadata

• Allows arbitrary relationships

among resource and metadata

objects: organization, annotation,

citation

• Accessible through web service

architecture of remixable data

sources and transformations

NSDL Data Repository (NDR)

• Implemented in Fedora 2.2 with MPTStore • Moderately large

– 4.7 million digital objects– 250 million RDF triples

• Digital Objects– Resources– Metadata– Agents– Metadata providers– Aggregators

• REST API and authentication• In production at nsdl.org

NSDL as Semantic Digital Library:

collaboration, context, and contribution

• Platform: Fedora repository and services

• Applications:– Solution 1: Leverage the existing successful models: blogs,

wikis, bookmarking/tagging

– Solution 2: Leverage the existing software: WordPress,

MediaWiki, Connotea, Sakai

– Solution 3: Engage with partners and the broader community

to build applications to the platform

Expert Voices - Blogs on top of Fedora

Expert Voices

• NSDL Blogosphere (http://expertvoices.nsdl.org)– Topic-based discussions (e.g. forensics) linked to related library

resources– A way for NSDL community members to become NSDL

contributors of resources, questions, reviews, annotations, metadata

• Technology:– Wordpress-based multi-user multi-blog application (open source,

plug-in architecture)– Owner controls publication of entries as NSDL resources and

visibility of comments (NSDL middleware and Shibboleth)

• Blog Entries:– linked references to NSDL library resources

NSDL 2.0 – The Whole Ecosystem

Protocol:OAI-PMHHTTPRESTNDR API

STEMCollections

SearchServiceArchive

Service

Fedora-based NDR

NSDL 2.0 and the Semantic Web

• NSDL 2.0 applications situate resources in context, aiding both

discovery and use

• Users become contributors, adding new resources, ratings,

annotations, and organizational structure – frequently as a side

effect of using the library

• Fedora-based semantic web technology organizes resources,

ties context to content, maintains provenance, enables discovery,

empowers the user, and powers the library

Fedora Web Site: www.fedora.info

Community Open Source Tools: www.fedora.info/tools

Fedora Wiki: www.fedora.info/wiki

Tutorial:: http://openarchives.org/fedora/ESWC-Fedora.zip

- Comparison and the Future -

Outline

SIMILE – short overview

Comparison between existing solutions

Digital Libraries and Social Web

Semantic Digital Libraries Scenarios

SIMILE – Introduction

• SIMILE - Semantic Interoperability of Metadata and

Information in unLike Environments

– joint project conducted by the W3C, HP, MIT Libraries, and MIT's Lab

for Computer Science.

– extends and laverages DSpace, seeking to enhance interoperability

among digital assets, schemata, metadata, and services

– Goal: Make metadata interoperability easier for digital libraries by

providing useful tools for browsing, searching and mapping

heterogeneous metadata in RDF [MacKenzie Smith, MIT Libraries]

SIMILE – Introduction

SIMILE:

• enhances interoperability and provides end-user services:

– for digital assets, arbitrary schemata, metadata and services.

– across distributed individual, community, and institutional stores.

– though the application of RDF and semantic web techniques.

• implements a digital asset dissemination architecture based

upon web standards

SIMILE – Delivered Components

• Tools for Metadata Managers– Gadget - XML inspector

– RDFizers - Batch tools to transform existing XML data into RDF

– Solvent - Firefox extension for Javascript screen scraping

– Welkin - Graphical tool to inspect/edit RDF graph

• Tools for End-Users– Longwell - Web-based RDF faceted metadata browser

– Piggy Bank - Firefox extension for personal information management of

metadata in RDF

– Semantic Bank - Web-based server that allows data publishing and sharing

by individuals, groups, or communities

– Exibit - lightweight structured data publishing framework

– Timeline - AJAXy widget for visualizing time-based events

RDFizers - Transform XML data into RDF

RDFizers - Transform XML data into RDF:

• tools that allow to transform existing data into an RDF representation

• List of RDFizers in SIMILE:– MARC/MODS RDF

– OAI-PMH RDF

– OCW RDF

– EMail RDF

– BibTEX RDF

– Flat RDF

– Weather RDF

– Java RDF

– Javadoc RDF

– Jira RDF

– Subversion RDF

– Random RDF

Solvent - JavaScript screen scraping

Solvent - JavaScript screen scraping:

• a Firefox extension that helps write Javascript

screen scrapers for Piggy Bank.

• Motivation:– Piggy Bank needs web pages to embed information in RDF.

– Unfortunately, not many web pages embed or link to RDF

information.

– Piggy Bank is capable to execute a particular screen scraper on

particular pages in order to "extract" the information it needs.

– turns a regular web page into a semantic web page, freeing the

data from the page/site that contains it.

Solvent - JavaScript screen scraping

Longwell - RDF faceted metadata browser

PiggyBank

• Firefox extension for managing metadata - Loads RDF into

local Longwell server

• Search and faceted browse of local RDF - Views defined by

library, other users

• Users can find, collect, annotate RDF - Can then publish for

access by others

PiggyBank

SemanticBank

• Semantic Bank use cases:

– persist information remotely on a server

– share information with other people

– lets you publish your information, both in RDF or to regular web pages

• for individuals, groups, communities - e.g. conference

proceedings

– the ability to tag resources creates a powerful serendipitous

categorization

– Longwell facetted browsing view of published information

Timeline

Exibit

Outline

System Features Comparison

JeromeDL BRICKS Fedora

OS Support Any Any Any

Hardware Requirements

500MB RAM, min 128MB HD

500MB RAM, min 100MB HD

500MB RAM,min 100MB HD

Software Requirements

Java 1.5, Tomcat 5.5, Sesame

Java 1.4/1.5, Jena

Java 1.5, Tomcat,Kowari/Mulgara or MPTStore

Current Stage Research Stable version 2.0.1

Second Prototype

ProductionVersion 2.2

No. Installations 12+ ~ 8 ~50 monitored; large # of downloads unmonitored

Support Model Open Source Open Source Open Source

General Properties

Distribution Distributed searching (P2P), aggregated browsing (hierarchical)

Fully decentralized (P2P)

federation via nameresolver search services; Alvis P2P

Architecture Granularity

Low (main building blocks)

High(many Components)

High (core repository service with configurable modules; loosely coupled services)

DB - Support Any Sesame-compliant backend

Any Jena compliant backend

MySQL, Postgres, Oracle, McKoi;Kowari/Mulgara

Architectural Aspects

Content Types All All All

Content Models JeromeDL ontology

Any Any

Metadata Schema MarcOnt + extensions

Any RDF/S & OWL schema

Any XML Schema, RDF/S & OWL schema

Query types Full-text, Filed-Search, Ontology-based, NL Query Templates

Full-text, Field-Search, Ontology-based (sparql)

Field Search,Ontology-based (itql, rdql, sparql, spo),Full-Text (Lucene or Zebra backed service)

Content & Metadata Aspects

Security Model FOAFRealm RBAC XACML Policy

Granularity Resource Component, Method, Object

Object, Datastream, Dissemination method

DRM Model Fair use DRM under development

MPEG-21 REL DRM Datastreams

DRM Enabling Tool Support

Watermarking

Security & DRM Aspects

Reasoning Recommendation engine based on Prolog

Configurable inference engine

Holding pattern; look to Mulgara;

Tagging Free tagging, Wordnet-based

Annotation middleware component

middleware/apps (e.g., NSDL/NDR; PLoSONE/Topaz)

Taxonomies Any (JOnto) Any Any

Knowledge Sharing

SSCF component via middleware upon BRICKS

via middleware upon Fedora

Communities SIOC and FOAF compliance

Semantic Aspects & Community Features

Outline

The future - Social Semantic Digital Libraries

• Why current (semantic) digital libraries are not enough?

– digital libraries should not be for librarians only but for average

people

– they concentrate on delivering content/information, not on

knowledge sharing within a community of users

– digital libraries have lost human-part of their predecessors

• What could be the solution?

– make users/readers involved in the content annotation process

– allow users/readers to share their knowledge within a community

– provide better communication between users in and across

communities

What is Web 2.0?– The Web where “ordinary” users can meet, collaborate, and share

using whatever is newly popular on the Web (tagged content, social bookmarking, AJAX, etc.)

– The term Web 2.0 was made popular by Tim O’Reilly: http://www.oreillynet.com/pub/a/oreilly/tim/news/2005/09/30/what-is-web-20.html

– Popular examples include: Bebo, del.icio.us, digg, Flickr, Google Maps, Skype, Technorati, Wikipedia…

The future - Social Semantic Digital Libraries (3)

• Web 2.0 focuses include:– The Web as a platform for social and collaborative exchange

– Reusable community contributions

– Subscriptions to information, news, data flows, services

– Mass-publishing using web-based social software

• Social software for communication and collaboration:– IM, IRC, Forums, Blogs, Wikis, Social Network Services, Social

Bookmarks, MMOGs…

Social Semantic Information Spaces

Comparing Web 1.0 / Web 2.0 / Semantic Web 2.0

Semantic Social NetworksOnline Social NetworksBuddy Lists, Address Books

Semantic Social Information Spaces

Social Semantic Digital Social Semantic Digital LibrariesLibraries

Google Scholar, Book Search

CiteSeer, Project Gutenberg

Semantic Forums and Community Portals

Community PortalsMessage Boards

Semantic BlogsBlogsPersonal Websites

Semantic SearchGoogle Personalised, DumbFind

Altavista, Google

Semantic WikisWikisContent Management

Systems

Semantic Web 2.0Semantic Web 2.0Web 2.0Web 2.0Web 1.0Web 1.0

Outline

Geo, Time, and Machine Tagging

• Geo-tagging for resources with a specific geographical

location

• Time-tagging – community driven process of assigning

auxiliary multimedia content

• Machine-tagging – ability to mix structured annotations

into tags

• ROI-tagging:

– Regions of interest

– ERP game

– Asynchonous version with annealing of annotations for less

frequently visited libraries

SDL in eLearning

• One of potential sources of future e-Learning systems

• On the verge between formal (libraries) and informal

(communities) learning sources

• Semantic interoperability with Learning Management

Systems

• Improve knowledge creation, delivery and sharing

SDL in Future Museums

• Museums have physical objects

• Should bind digital annotations with physical objects

• Real-virtual tours

– Start with real, guided tour

– Ubiquitous browse through context information

– Locate other exhibitions in the vicinity

– Share your knowledge and experience with others, leave bread-

crumbs for others

– Get the most of the exhibition during your visit

Discussion – Feedback

The Librarian from Unseen University in Ankh-Morpork (formerly Dr. Horace Worblehat)

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