=Paper=
{{Paper
|id=None
|storemode=property
|title=Introducing the Semlib Project: Semantic Web Tools for Digital Libraries
|pdfUrl=https://ceur-ws.org/Vol-801/paper9.pdf
|volume=Vol-801
|dblpUrl=https://dblp.org/rec/conf/ercimdl/MorbidoniGNFL11
}}
==Introducing the Semlib Project: Semantic Web Tools for Digital Libraries==
https://ceur-ws.org/Vol-801/paper9.pdf
Proceedings of the 1st International Workshop on Semantic Digital Archives (SDA 2011)
Introducing the Semlib project: semantic web
tools for digital libraries
Christian Morbidoni a,1 , Marco Grassi b,1 , Michele Nucci c,1 , Simone Fonda d,2 ,
and Giovanni Ledda e,1
1
Semedia Group, Università Politecnica delle Marche, Italy
a
christian.morbidoni@gmail.com, b m.grassi@univpm.it,
c
mik.nucci@gmail.com, e g.ledda@univpm.it
http://www.semedia.dibet.univpm.it/
2
NET7, Italy
d
fonda@netseven.it
http://www.netseven.it
Abstract. It is a common opinion that today’s digital libraries (DL)
can no longer be simple “expositions’ of digital objects. Users should
no more be passive readers, they need to interact with the library, add
their annotations and tags, personalize their experience and collaborate
with each other. Web 2.0 technologies, such as social bookmarking and
online discussions, are already being applied in DLs to allow users to
annotate digital objects. However, the lack of semantic structure of such
annotations and a clear social model to share and aggregate community
contributions makes it difficult to take full advantage of such collabora-
tively created knowledge.
The SemLib project aims at developing a modular and configurable an-
notation system that can be easily plugged into existing digital libraries
in order to allow end-users as well as digital libraries content curators to
produce meaningful and customizable aggregations of semantically struc-
tured annotations produced by communities. In this paper we introduce
the SemLib project, discussing the principles and ideas behind the pro-
posed annotation system, and present a prototypal implementation.
Keywords: Digital libraries, Semantic Web, Ontology, Data Model
1 Introduction
Nowadays, Digital Libraries (DL) are applied in many different contexts ranging
from academic institutions to public libraries, archives, museums and industries.
Traditionally DLs, as well as Web itself at its beginning, have been based on the
expert paradigm according to which experts create content, DL experts provide
access to it, and individual users consume it [1]. The advent of Web 2.0 has lead
to a Copernican revolution in the Web universe that has pushed users more and
more toward its center and transformed them from passive content consumers
into primary actors in data and metadata creation. As a result, tagging, linking
and commenting resources have become common activities for Web users and a
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Proceedings of the 1st International Workshop on Semantic Digital Archives (SDA 2011)
valuable source of metadata that can be exploited to drive resource ranking, clas-
sification and retrieval. Annotation creation and sharing in a research context is
an established practice since the pre-digital era, therefore its not surprising that
in the last years the application of Web 2.0 models has been widely investigated
in the context of digital humanities.
One of the ideas at the base of the research and development activities in
this field is that user-created annotations, if properly structured and machine-
processable, can enrich Web content and enhance search and browsing capabili-
ties. Also allowing users write-access to the collection in DLs can provide users a
more engaging experience and “capture diffuse and ephemeral information’ [2].
Supporting social annotations has proved to be an enabling feature for scholars to
actually benefit from the digital world in their everyday work. Experiments con-
ducted within the Discovery3 european project have clearly shown that building
structured information by annotating Web documents can be a valuable mean
of representing aspects of the study process e.g. in e-learning or classroom ac-
tivities. In [3], authors make a distinction between “social engagement’, where
users annotate contents for their own purposes (e.g., to better organize study
resources), and crowdsourcing, where social engagement is used within groups
of users (communities) to “achieve a shared goal by working collaboratively to-
gether as a group’. If social engagement has been addressed to a certain extent
by modern DLs, they rarely provide support to exploit such collected knowledge
to improve libraries metadata, enrich contents, searching and linking different
contents together. However, the topic is of high interest and not entirely new
to the DLs community, as witnessed by interesting ongoing projects like Dig-
italkoot4 , which is engaging people through online games, which create different
kind of structured contents.
Basing on previous research and developments in Semantic Web oriented
collaborative annotations (e.g.: SWickyNotes5 ), the SemLib project6 , shortly
presented in section 2, aims at developing a flexible, collaborative annotation
system to address single scholars and unregulated user communities as well as
curated “authoritative’ annotations to incrementally enrich digital contents.
In this paper we discuss the data and social model designed during the
project’s first phase, presenting a preliminary prototype composed by experi-
mental GUIs to create and exploit annotations and a triple-store based annota-
tion server providing RESTful APIs to create, share and consume them. This
paper is organized as follows: chapter 2 shortly presents the SemLib project;
chapter 3 provides a brief overview of existing cutting-edge tools for resource
annotation; chapters 4 and 5 discuss the annotation system architecture and
chapter 6 demonstrates the experimental prototype.
3
ECP 2005 CULT 038206 project, EC eContentplus programme
4
http://www.digitalkoot.fi/en/splash
5
http://www.swickynotes.org
6
http://www.semlibproject.eu/
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2 The SemLib project: use cases and challenges
The SemLib project, funded by the European commission, aims to improve the
current state of the art in DLs, through the application of Semantic Web (SW)
technologies for data representation and management. One of the main expected
outputs of the SemLib project is the design and implementation of an annota-
tion system able to enrich and interconnect digital objects published on the
Web, specifically targeting DLs and multimedia archives owned by participating
SMEs. As such objects are different, both from technology and from type of
provided content points of view, the annotation system has to be designed to be
technologically decoupled from the DL (adopting a RESTful architecture), based
on established standards in data and metadata representation (such as RDF and
Semantic Web ontologies), domain agnostic and adaptable or configurable for a
variety of different use cases.
Resources annotation should be supported at different granularity levels in
order to enhance resource fruition and interaction. With respect to this require-
ment, Web standards such as XPointer7 and Media Fragment URI8 are being
used respectively to unambiguously identify text excerpts in Web pages and
subparts of images and audio-video resources. In addition, as digital content can
be remixed and replicated inside a DL (e.g. in summary pages or in compos-
ite, derivative digital objects), annotations should address not only entire web
pages (has it happens for the majority of existing tools), but also small, atomic
unit of content, like pictures, single text paragraphs, etc. Also, as SEMLIB aims
at addressing different kind of users, they should be allowed to create different
types of annotation, structured according to different levels of complexity and
provided with diverse expressive flavor and semantics, from natural language
comments to semantic tags coming from a restricted vocabulary to full subject-
object-value statements based on domain ontologies. Moreover, SemLib should
provide tools and models capable of leveraging the process of collaborative and
community driven annotation of DLs items. This is an important requirement
both for engaging small unregulated end-user communities and for providing ef-
fective tools for scholarly communities and DL maintainers to incrementally and
collaboratively enrich the quality of metadata (e.g. basing on a crowdsourcing).
The several high level challenges, which have to be tackled in order to ac-
complish SemLib’s goals, can be summarized as follows:
– supporting DLs in aggregating users in communities by providing properly
configured tools and uniform domain vocabularies to create interoperable
metadata;
– enabling a social model where end-users, as well as content owners, create,
share and aggregate annotations into personal, curated “views’ of the collec-
tive knowledge base;
7
“XML Pointer Language (XPointer)” http://www.w3.org/TR/xptr/
8
“Media Fragments URI 1.0” http://www.w3.org/TR/media-frags/
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Proceedings of the 1st International Workshop on Semantic Digital Archives (SDA 2011)
– providing DLs with visual tools and APIs to exploit the collective knowledge
base, slice it accordingly to custom policies and make it available to end-users
for searching, browsing and studying online content;
– developing annotation GUIs capable of efficently handling the trade-off be-
tween the ease of use and the creation/management of meaningful structured
data.
3 Related Work
In recent years, several annotation systems have been developed. These allow
Web resource annotation providing different approaches and functionalities to
be applied in different application scenarios. Some applications have been devel-
oped as extensions of popular social bookmarking tools, as Delicious9 or Stum-
bleUpon10 , that count millions of registered users. Other tools have been more
specifically conceived for creating and sharing annotations of digital resources
for supporting e-learning, collaborative tasks, such as document reviews or edit-
ing, and in general working group cooperation. A complete review of the state
of the art tools for Web resources annotation goes beyond the purpose of this
work and can be found in [4]. Some of the most interesting applications are now
presented and discussed, with regard to SemLib project.
EuropeanaConnect Media Annotation Prototype (ECMAP) [5] is an online
media annotation suite based on Annotea [6] that allows users to extend exist-
ing bibliographic information about digital items like images, audio and videos.
ECMAP allows free-text annotations and semantic tagging, enabling Linked
Data resource linkage in the user annotation process, in addition to the possibil-
ity to draw user-defined shapes on images, maps and videos. Special support is
also provided for high-resolution map images, enabling tile-based rendering for
faster delivery, geo-referencing and semantic tag suggestions based on geographic
location. ECMAP’s annotation system presents several similarities with SemLib,
in particular in the overall idea of supporting various types of resources. For this
reason, it represents an important reference to identify the basic features that
SemLib annotation system should have. LORE (Literature Object Reuse and
Exchange) [7] is a tool developed inside the Aus-e-Lit Project “to enable schol-
ars and teachers of literature to author, edit and publish compliant compound
information objects that encapsulate related digital resources and bibliographic
records’. The OAI-ORE Resource Map11 is used as the main data model and a
specific ontology has been defined to describe the relationships among objects,
called LORE Relationship Ontology. The annotation tool provides a graphical
user interface for creating, labeling and visualizing typed relationships among
individual objects, using terms from a bibliographic ontology. While the user in-
terface is powerful, it probably lacks in simplicity and would not be so straight-
9
http://http://www.delicious.com/
10
www.stumbleupon.com/
11
Open Archives Initiative Object Reuse and Exchange
http://www.openarchives.org/ore/0.9/primer#ResourceMap
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forward to understand for non-expert users. However, LORE is an interesting
source of inspiration, since it presents several conceptual similarities with the
SemLib annotation system. One Click Annotator [8] is a WYSIWYG Web edi-
tor for enriching content with RDFa annotations, enabling non-experts to create
semantic metadata. It allows the annotation of words and sentences, referencing
ontology concepts and creating relationships among annotated sentences. The
Open Knowledge Foundations Annotator12 project is developing a Web-based,
open-source annotation tool that, from a user interaction perspective, has simi-
larities to SemLib annotation tools. It uses XPath to anchor textual annotations
and tags to specific parts of a page, providing also a server-side module for
storing annotations represented as JSON data.
The idea of semantic tagging is implemented in Faviki13 , a social bookmark-
ing tool that allows the use of Wikipedia concepts as tags for Web pages. Tags are
suggested using auto completion, allowing disambiguation, where the suggested
items are ordered by their use frequency. It also proposes tags automatically
extracted from the page using Zemanta14 . Several Web annotation tools exist,
which do not make use of structured semantics and handle simple textual an-
notations. Among those, Diigo15 (Digest of Internet Information, Groups and
Other stuff) is a social bookmarking application, which allows signed-up users
to bookmark and tag Web pages. In addition, Diigo allows users to highlight
any part of a Web page, attaching sticky notes to it. Diigo provides a simple but
interesting annotations sharing model: annotations can be kept private, shared
with a group within Diigo or forwarded to someone else with a custom link.
4 Representing semantically structured annotations
Annotations represent a peculiar type of resources that is specifically conceived
to add information to other resources. Annotations acquire therefore full sig-
nificance in relation with the target resource and other contextual information,
such as its author, its creation date and the vocabulary terms used. Properly
structuring an annotation is therefore necessary at twofold level. On the one
hand, an annotation represents an “information container’, whose structured
metadata make contextual information explicit. On the other hand, an anno-
tation includes an informative content that expresses a “knowledge bit’ about
annotated resources. Such knowledge is strongly domain dependent and, when
uniformly structured by means of shared ontologies, can be in turn aggregated
and used to increase content accessibility and interoperability.
Several ontologies have been developed in the last few years to provide a
generic annotation structure and to improve interoperability among different
annotation tools [9] [10]. The Open Annotation Collaboration16 (OAC) project
12
http://okfn.org/projects/annotator/
13
http://www.faviki.com/
14
http://www.zemanta.com/
15
http://www.diigo.com/
16
http://www.openannotation.org/
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recently published the first specifications of the OAC data model [11], which
at the moment seems to be the most accepted by the Digital Humanities com-
munity. In our first implementation the OAC ontology has been adopted and
extended. It provides solid support for contextual metadata and for attaching
annotations to involved Web resources. Such resources can be entire media ob-
jects or fragments (basing on Media Fragments and XPointer). Other ontologies,
like the Annotation Ontology17 , mostly used in bio-science community, have sim-
ilar structure and comparable expressivity. In such ontologies annotations have a
payload (body) that represents the user-created informative content. In practice,
this is usually a Web page (e.g. a blog entry) or a textual comment.
One of the first issues we had to tackle was how to represent annotations that
have an RDF graph as body. Even if this specific case is starting to be discussed
within the community, it has not yet been regulated by the OAC specification
that makes no assumption on the kind of body an annotation can have. It can
be, for example, a plain text or a resource with its own URI. In RDF, there are
different methodologies to model such a situation, from standard reification, to
Content in RDF [12] or some ad-hoc solutions. As our primary goal is to prove
how RDF triples produced by users can be aggregated using flexible criteria, we
found it convenient to adopt named graphs to represent semantically structured
annotation content. In our model, each annotation has an ”oac:body” that is
associated with a named graph, where the informative content is represented in
triples. This allow us to exploit standard support for named graphs in SPARQL
and in triplestores, thus querying and accessing only little “slices’ of the entire
collaborative knowledge graph. As discussed in detail later, this is very important
to support personal views and target use cases.
The annotation storage is agnostic with respect to the ontologies used to rep-
resent the informative content of annotations. However, communities and DLs
would greatly benefit from the uniformity of the data schema and vocabulary
used in annotations. Our approach allows DLs to deploy specific configurations
of the annotation tools provided, enabling users to transparently adhere to pre-
defined data schemas. A range of pluggable entity spaces (like ontologies or the-
sauri) can be used in practice to provide users with a shared common vocabulary,
enabling effective structured descriptions of any knowledge domain at different
levels of expressiveness and with different structures. At the current stage, the
annotation tool supports both “open’, relatively flat vocabularies like Freebase
(leveraging the reconciliation APIs18 ) and restricted controlled vocabularies and
taxonomies, e.g. based on the SKOS model [13]. The following example in N3
syntax shows how an annotation and its informative content are represented in
RDF.
Listing 1.1. An annotation example in N3 notation
// contextual metadata
ex : ANNOTATION - ID -1 a oac : Annotation ;
rdfs : label " My test annotation ";
dcterms : created "2011 -01 -27 10:30:56";
17
http://code.google.com/p/annotation-ontology/wiki/Homepage
18
http://wiki.freebase.com/wiki/Freebase API
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dcterms : creator ex : C hr i s t i a n M o r b i d o n i ;
oac : hasBody ex : ANN - BODY - ID -1 ;
oac : hasTarget http :// example . com /1. htm ;
oac : hasTarget http :// example . com /1. jpg .
ex : ANN - BODY - ID -1 a oac : body ;
rdfs : comment " This is an optional comment " ;
semlib : graph ex : graph - ann1 .
// informative content
ex : graph - ann1 {
http :// example . com /1. htm tags : hasTag http :// www . freebase . com / view / en /
pippo_baudo ;
http :// example . com /1. jpg foaf : depicts ex : PippoBaudo ;
http :// example . com /1. jpg ex : is - related - to http :// example . com /1. htm .}
5 Addressing digital content and fragments
While the system is designed to work on generic web pages, there are some
features that pose some requirements on DLs to better handle annotations. Two
main issues have emerged from the analysis of the SemLib use cases and previous
experiments.
DLs, like other web 2.0 applications, change over time. Presentation can be
restyled and content can be re-organized. In addition, the same content (e.g. a
page of an essay) can be accessible via different Web location (e.g. a summary
page and the whole essay page). If we want annotations to remain consistent in
such cases, in particular when they are shared in communities and not under a
centralized control, we need a way of unambiguously identify atomic, annotable
contents in DL Web pages. For this reasons the annotation system requires DLs
to include RDFa tags to wrap atomic content, the granularity being opportunely
tuned to address specific needs. Each marked content should have a resolvable
URI associated, to which annotations are attached. This allows also for an anno-
tation to be automatically associated to all pages that include the same content,
as it might happen, for example, for derivative works.
As it happens for stand-off markup in general, the annotated content can
change itself, e.g. typos gets fixed or corrections are made by editors. In such
cases, annotations referring to fine granular fragments (e.g. sentences or words)
can become invalid or simply no more addressable in the modified version. While
editorial changes in some DLs result in new versioned objects, this is not a rule in
practice, and preserving annotations through content modifications and revisions
can be useful in publication workflows. In SemLib, this issue has not been fully
addressed yet, but the model is “tolerant’ to content change. We use XPointers
to address DOM documents fragments of the marked content, but we also store
the original annotated content, checking for broken annotations and possibly
alerting the user when they are shown.
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6 Sharing annotations
In our system users collect their annotations in notebooks, which are private by
default but can be made public and shared with others. Notebooks are identified
by dereferenciable URLs that applications can use to retrieve RDF-encoded an-
notations and relative metadata in different formats (RDF/XML, JSON, etc.).
Being able to collect annotations in different notebooks helps users in organizing
their work and in grouping annotations by topic or task, furthermore it allows
users to make available to others subsets of their annotations.
Sharing a notebook is as easy as sharing its URL on the web, similarly to
what happens for popular file sharing platforms. At the moment our system does
not provide a social network itself where notebooks can be shared, rather the
idea is that of relying on existing communication tools and social media that
users are already familiar with. For example, if users want to share a notebook
with a single person (e.g. a colleague), they can send the url via mail. In other
cases, where users wants make a notebook of public domain, twitter, facebook or
other social media can be used as publishing channels. This simple mechanism is
general enough to enable different collaborative scenarios, but has limitation in
terms of security: once a notebook is made public, each user that receive or find
somewhere its URL can access the annotations. In later versions of the system,
in order to better address real world use cases, owners of a notebook will be able
to explicitly grant read and write permissions to other users of the annotation
system. When a users receive an invitation to view a notebook (e.g. receiving
the URL by mail) they simply click on it and, if signed in to the annotation
system, they are redirected to the notebook web page where they can “activate’
it. Each user has a personal preference page where he/she manage the list of
active notebooks. When a notebook is active its content is visible to the user
while annotated resources are browsed. In other words, by properly configuring
the environment, users will be able to aggregate their and others annotations
and explore them as custom semantic graphs.
7 Creating crowdsourced annotation collections
DL owners interact with the annotation system in two ways. On the one hand
they deploy custom configuration of the system to deliver domain specific anno-
tation tools to their users, by including Javascript libraries into their Web pages
or suggesting shortcuts as bookmarklets to users. Using such annotation tools,
communities of users, around single or federated DLs, can transparently produce
metadata adhering to agreed schemas and vocabularies. This in turn makes the
collectively produced data interoperable with the DL itself.
On the other hand, DLs owners/maintainers can act as content curators. As
such, they might want to make their own annotation but also to select rele-
vant end-user contributions, aggregate them and, perhaps implement a proper
contribution submission workflow (as it happens, for example, with reviewed
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Proceedings of the 1st International Workshop on Semantic Digital Archives (SDA 2011)
publications). This would in turn enable a reward based scenario that can stim-
ulate users to contribute. While SemLib does not implement any specific pub-
lication workflow, the intent is that of providing a framework that applications
can base on to implement their own. In practice, content curators would act as
“power users’ of the annotation system. They produce their own annotation as
regular user do, and they can copy annotations from users-created notebooks
to their own notebooks, preserving authorship and other contextual metadata.
Such curated notebooks, along with their informative structured content, can be
delivered back to users as trusted/official annotations, or directly imported to
enrich the DL. In the first case a properly configured GUI, once embedded in
the DL, could show the official annotations distinguishing them from users per-
sonal notebooks using some visual effect. In the second case, DLs can use simple
REST APIs provided by the system to consume RDF encoded annotations and
import them into their own database. Experiments in this directions are being
made in SemLib, where some of the involved SME’s products are natively based
on RDF.
8 Prototypal implementation
At the time of writing, the annotation system implementation has reached a
prototype stage and, while collaborative features are still not fully implemented,
is supports annotation of generic Web contents. It can be used in any existing
Web site without modification to its structure and source-code, it is completely
decoupled from the Web sites or DLs to be annotated and can be run by end-
users through a dedicated bookmarlet. The system is made of two main macro-
components: a client-side and a server-side component. When a user launches the
bookmarklet, the client-side component is automatically plugged into the web
page the user is currently browsing. The client-side component comprises a set
of sub-modules developed in Javascript using the dojo framework 19 to facilitate
cross-browser support. The client-side module implements the graphical user
interfaces to create and browse annotations as well as modules dedicated to the
communication with the server. Among these components the most important
are the Fragment Handlers, the Resource Selectors and the annotation composer,
called Pundit. Their interactions are depicted in Fig. 1.
During the annotation process, Fragment Handlers and Resource Selectors
allow users to import different kind of resources into Pundit, where they can
be used to compose structured annotations. Fragment Handlers and Resource
Selectors can be configured by the system administrator to use specific vocabu-
laries. Fragment Handlers assist users in selecting parts of content (eg. parts of
a web page, parts of images, video frames, etc.) and turn them into actual ad-
dressable resources (e.g. using XPointer) to be used into annotations. Fragment
Handlers also have the role of resolving resource fragments involved in exist-
ing annotations so that they can be highlighted in the page. Resource selectors
have a similar role: they allow users to import into Pundit selected terms from
19
http://dojotoolkit.org/
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Proceedings of the 1st International Workshop on Semantic Digital Archives (SDA 2011)
Fragment Handlers Selectors
Text Reconciliation
Pundit
Image Vocabulary
Client
Video Predicate
... ... ... ... ... ...
Annotation Annotation
Viewer Writer
Annotations Users Annotations
Consuming API Management API Authoring API
Server
Storage System
Fig. 1. Simplified architecture of the annotation system
a vocabulary or entity space. Resources are typed, where types are addressable
resources as well (as it happens in RDF Schema). The current prototype imple-
ments two kind of selectors: one based on the Freebase reconciliation service and
one presenting vocabs from a configurable domain taxonomy (e.g. conceptually
equivalent to a SKOS vocabulary). Once resources are added to Pundit, users
can build structured information in the form of triples (subject, predicate and
object), by specifying semantically typed relations that links them, chosen from
a predefined, configurable list or RDF properties. Pundit uses domain and ranges
of such properties to assist the user and suggest proper relations for different
kind of resources. At the current state, the discussed modules can be configured
via simple JSON files. However, as the underlaying model is an RDF Schema
ontology, such a configuration could be easily extracted from a SPARQL end-
point. This might be useful if the DL exposes its data schema and resources
via Semantic Web standard mechanisms such as SPARQL and Linked Data.
This point will be addressed later in the project. The screenshot in Fig. 2 shows
the prototypal user interface to compose semantic annotations. Users can select
fragments of the page and import them into Pundit, where they can be dragged
to populate statements. Users can also import resources from provided custom
taxonomies (like the simple one in the illustration) or from Freebase, and again
use them in annotations.
Once triples have been edited, user can save them to the Annotation Server,
which is a modular RESTful web-service. It allows annotation storage, user au-
thentication and management in addition to APIs for annotation authoring, con-
suming and sharing. Such RESTful APIs, partially inspired by previous works
as the Annotea Protocol, allow users to create new notebooks and annotations
supporting different data formats (e.g. RDF, JSON, etc.), to browse notebooks
and related annotations and to personalize users views by activating public note-
books (e.g. shared by others). Such aggregations of activated notebooks can be
then exploited by querying them and retrieving semantic data in the form of
RDF triples. A typical use of such querying functionalities is that of retriev-
ing all the RDF statements where a particular web resource (or a fragment of
it) is involved. Sub-graphs obtained in this way can be immediately explored
with existing Semantic Web aware tools. A prototypal annotation navigator, for
example, has been implemented using Simile Exhibit.
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Proceedings of the 1st International Workshop on Semantic Digital Archives (SDA 2011)
create resources
from fragments of the page
import resources
from a controlled vocabulary
drag resources and relations
to compose semantic statements
Fig. 2. A screenshot of Pundit in action
The storage module defines a completely generic interface, designed to sup-
port different kind of storage systems ranging from traditional relational databases
to NoSQL databases (eg. RDF triplestores). In the prototype version, the stor-
age is implemented using the Sesame triplestore 20 as this greatly simplifies
handling and exporting RDF data. The storage module, besides keeping users
annotations, stores also user profiles and related contextual information (e.g.:
user’s metadata, user’s permissions etc.). The Annotation Server supports two
single sign-on systems for users authentication, in particular, Open-ID21 and
OAuth22 . Different authentication systems can be easily implemented develop-
ing dedicated plugins. Using single sign-on systems simplifies the integration of
the annotation system with existing DL, which may already provide facilities for
users authentication.
9 Conclusions
In this paper, we introduced the SemLib project, focusing on the proposed data
and social model and explaining how those are expected not only to foster anno-
tation sharing between DL communities and user engagement but also to allow
the application of crowdsourcing paradigm in the creation of added value for
the DLs. As proof of concept of our ideas, we also presented an early proto-
type implementation of the system discussing the experimental client-side GUIs
for annotation creation and the server’s RESTful APIs for annotation storage,
sharing and consumption.
20
http://www.openrdf.org/
21
http://openid.net/
22
http://oauth.net/
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Proceedings of the 1st International Workshop on Semantic Digital Archives (SDA 2011)
As SEMLIB is an ongoing project, not all the features here described have
been implemented yet, and several challenges are still open in improving annota-
tion creation, visualization and sharing, which will be tackled in future releases
of the annotation system. Also, the proposed system will be extensively tested on
existing DLs of partner SMEs, which is expected to provide valuable feedbacks
and to further boost the development process.
10 Acknowledgments
The research leading to these results has received funding from the European
Union’s Seventh Framework Programme managed by REA-Research Executive
Agency23 ([FP7/2007-2013][FP7/2007-2011]) under grant agreement n. 262301.
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