=Paper=
{{Paper
|id=Vol-273/paper-16
|storemode=property
|title=SOBOLEO -- Social Bookmarking and Lighweight Engineering of Ontologies
|pdfUrl=https://ceur-ws.org/Vol-273/paper_41.pdf
|volume=Vol-273
|dblpUrl=https://dblp.org/rec/conf/www/ZachariasB07
}}
==SOBOLEO -- Social Bookmarking and Lighweight Engineering of Ontologies==
https://ceur-ws.org/Vol-273/paper_41.pdf
SOBOLEO – Social Bookmarking and Lighweight
Engineering of Ontologies
Valentin Zacharias Simone Braun
Forschungszentrum Informatik, FZI Forschungszentrum Informatik, FZI
Haid-und-Neu Strasse 10-14 Haid-und-Neu Strasse 10-14
76131 Karlsruhe, Germany 76131 Karlsruhe, Germany
zacharias@fzi.de braun@fzi.de
ABSTRACT the group using it. These barriers cause communica-
We present SOBOLEO, a system for the webbased collab- tion problems: new requirements are collected from
orative engineering of SKOS ontologies and annotation of the users and need to be understood by the knowledge
web resources. SOBOLEO enables the simple creation, ex- engineers; in turn, changes to the shared vocabulary
tension and maintenance of taxonomies. At the same time, need to be explained to the users [9].
it supports the annotation of web resources with concepts 4. The use of different sets of tools for the creation/main-
from this taxonomy. tenance and for the use of a structured vocabulary
often results in less frequent updates to the shared
Categories and Subject Descriptors vocabulary. This again causes time lags between the
moment a new concept emerges in the domain and its
H.5.3 [Information Systems]: Group and Organization
inclusion in the vocabulary. It has been shown that
Interfaces; H.3.3 [Information Systems]: Information
even modest time lags can make structured vocabu-
Search and Retrieval; H.3.5 [Information Systems]: On-
laries unusable for fast moving domains [9].
line Information Services; H.4.3 [Information System Ap-
plications]: Communications Applications For these reasons, tools for collaborative creation of shared
vocabularies need to be usable by the people in the domain
General Terms themselves. And—at least in fast changing domains—there
Design, Human Factors must be a simple, quick and seamless way to change the
shared vocabulary underlying an application.
Keywords 2. THE SOBOLEO SYSTEM
Ontology engineering, social software, collaboration, anno- In order to satisfy these requirement we developed SOBO-
tation, SOBOLEO LEO. SOBOLEO is the acronym for Social Bookmarking
and Lightweight Engineering of Ontologies. The system’s
1. INTRODUCTION goal is to support people working in one domain in the
So far, there is no integrated tool, which supports the collaborative development of a shared vocabulary and of a
collaborative creation of an index of relevant web resources shared index of relevant web resources. With SOBOLEO it
together with the shared vocabulary used to organize it. To- is possible to create, extend and maintain taxonomies ac-
day’s tools either allow the creation of a shared vocabulary cording to the SKOS Core Vocabulary [2] in a simple way.
or to structure information resources according to some fixed It also supports the collection and sharing of relevant web
vocabulary. In addition, most tools for editing a shared vo- resources (bookmarks). These bookmarks can be annotated
cabulary are tailored to people with training in knowledge with concepts from the SKOS taxonomy or arbitary tags for
engineering and not for domain experts. That results in a better retrieval. One instance or installation of SOBOLEO
number of problems for using such tools: is meant to be used by a community with interest in build-
ing a shared vocabulary and a web index. Within this one
1. Involving engineering experts for knowledge formula- instance, the users create and maintain one taxonomy and
tion and modelling causes the creation of a shared vo- one shared index of web resources collaboratively.
cabulary to be more expensive [1].
3. SYSTEM FUNCTIONALITIES
2. Knowledge engineers often have only a limited under-
SOBOLEO is based on AJAX technology and works in
standing of the domain and thereby introduce more
most current browsers (we tested Internet Explorer 6 and 7,
errors [1].
Opera 9, Firefox 1.5 and 2.0). It consists of four major parts:
3. Organizational barriers arise from the fact that the (1) a collaborative real time editor for changing the taxon-
group of people creating a vocabulary is different from omy, (2) a tool for the annotation of web resources, (3) a
semantic search engine for the annotated web resources, and
Copyright is held by the author/owner(s).
WWW2007, May 8–12, 2007, Banff, Canada. (4) a taxonomy browser for navigating the taxonomy and the
. content of the web resources index. Editing the taxonomy
Figure 2: The annotation pop up.
time, the message pane acts as chat window and shows all
exchanged chat messages. An input field below allows the
user to send chat messages to other users currently editing
Figure 1: The editor for the structured vocabulary. the taxonomy.
or the index of web resources requires authentification. The
other areas are open accessible. In the following paragraphs 3.2 Annotation of Web Resources
we will describe each of these parts. Clicking on the annotate button anywhere in SOBOLEO
opens the annotation interface (see Figure 2) as a pop up. In
3.1 Editor this interface, users can enter the url and the title of the doc-
SOBOLEO uses a subset of SKOS [2] as the format for ument they want to add to the index. In another input field
the structured vocabulary or taxonomy. It supports con- they can add a number of concepts from the taxomomy or
cepts and broader, narrower and related links between them. arbitary tags to annotate this new resource. This topic field
Concepts have a preferred label and a description; they can offers auto completion of entities in the taxonomy2 to en-
have any number of alternative labels. courage users to apply these concepts. Tags not previously
Entering the editor after succesfull authentification, a user known to the system can be used as well and will appear in
sees the current state of the taxonomy and the changes of the taxonomy editor as “prototypical concepts”; users can
other users in realtime. consolidate and move them within the taxonomy later. In
The interface of the editor (see Figure 1) consists of three this way we allow for the seamless gathering of new concept
main parts. To the left of the screen is a tree display of the ideas when they are occuring.
taxonomy. It shows the preferred labels of the concepts and A better way to use the annotation tool is, however, to
the tree formed by the narrower-broader-relations between drag the annotate button on to the browser bookmarks,
them. Users can drag’n’drop concepts on other concepts to where it will work as a bookmarklet. Whenever a user visits
create new broader relations or drag’n’drop while pressing a site she deems interesting for the index, she can click on
shift to remove them1 . The operations cut, copy and paste the bookmarklet and it will open the annotation interface
(and their shortcuts) are also supported on the concepts in with url and title already filled in based on the page that is
the taxonomy. Buttons below the taxonomy tree allow for open in the browser.
the creation and deletion of concepts. The SOBOLEO system automatically sends out a crawler
Clicking on a concept displays its details in the center to any newly added url to fetch and index the contents of the
part of the screen. The input fields at the center of the page3 . The contents of the page together with any concepts
interface can be used to edit the relations between concepts, used to annotate it gets added to the index.
the labels and the description of the concept. The editing of Whenever the annotate interface is opened for a particu-
relations between concepts is supported by auto completion lar url, the system checks whether there is already an an-
of entities in the taxonomy. notation. If so, the annotation is displayed and can also be
The right part of the screen is reserved for message. The
2
message pane displays automatically generated messages for Based on the preferred label of the concepts
3
all changes made to the taxonomy by any user. At the same Please note that SOBOLEO cannot add the content of sites
that use frames or require authentification—in these cases
1
Removing broader relations in this way is currently not only the title, the url and the annotated concepts will be
working in Firefox saved
Figure 3: The search result page.
Figure 4: The taxonomy and associated web resources
edited. In the current system one instance of SOBOLEO
browser.
has one annotation per url. This annotation consists of a
title and an arbitrary numbers of concepts. Annotations are
maintained collaboratively. (see Figure 4). Starting from the root concepts, the users
can click through the taxonomy concepts. On top, the users
3.3 Searching see the currently selected concept with its preferred and
SOBOLEO includes a semantic search engine support- alternative labels and its description. Additionally, all its
ing search and retrieval of the indexed web resources. The broader, narrower and related concepts are displayed as links
SOBOLEO search engine is used by typing search terms into for further navigation. Underneath the concept details there
a text field—similar to common internet search engines. The is a list of all resources which are annotated with the cur-
entered search string, however, is analyzed for occurrances of rently selected concept or with one of its narrower concepts.
concept labels from the taxonomy. An occurrance of a label These resources are further ranked by their date they were
of a concept in a search string is understood as a reference collected, thus the newest resources appear upmost.
to a concept. If references to concepts can be found, the
SOBOLEO search engine searches for web resources anno- 4. IMPLEMENTATION
tated with these concepts or narrower ones (related concepts
are currently not regarded). The results from the semantic The server side of SOBOLEO is implemted in Java on
search are combined with the result from a full text search top of the Apache Tomcat [16] application server. The sys-
in the contents of all annotated pages. tem uses Jena [3] for RDF processing, Hibernate [10] and
On the result page (see Figure 3) the SOBOLEO search HSQLDB [12] for persistance. The index of web resources
engine gives feedback on which concepts it understood the and the semantic search is build on top of the open source
query to be referencing. Depending on the search string, framework Lucene [14]. The client side AJAX interfaces are
the results and the taxonomy, the system may also propose created with Google’s GWT framework [8].
a number of query refinements or relaxations. The interface
lists all found resources with their title linking to the original 5. RELATED WORK
page, with annotated concepts, a short excerpt of the page A large number of other approaches for the creation of
content highlighting the search terms and the exact url. The structured vocabulary and the building of a shared web in-
edit links for each result allow to quickly modify or remove dex exist. We consider the semantic wikis (i.e. [13, 15]) and
the annotation of a web resource. The annotation pop up social web annotation tool like del.icio.us to be the most
interface is used (see Figure 2). relevant (i.e. [6, 11, 5, 7, 4]).
Compared to Semantic Wikis it is immediately obvious
3.4 Taxonomy Browsing that SOBOLEO is much more spezialized. Semantic Wikis
With the browsing interface users can navigate through are general purpose knowledge formulation tools—SOBO-
the taxonomy and the content of the web resources index LEO is deliberately restricted to a simple subset of SKOS.
Because of this restriction SOBOLEO can offer more spe- International Conference on Principles of Knowledge
cialized user interfaces and search facilities making it faster, Representation and Reasoning, pages 488–497, 2004.
simpler and more effective for the creation of a shared web [2] D. Brickley and A. Miles. SKOS Core Vocabulary
index together with the taxonomy used to organize it. SO- Specification. W3C working draft, W3C, November
BOLEO’s editor also allows for a closer collaboration among 2005.
the editors and virtually eliminates the chance for edit col- [3] J. Carroll, I. Dickinson, C. Dollin, D. Reynolds,
lisions. On the other hand, however, it is unclear whether A. Seaborne, and K. Wilkinson. Jena: Implementing
SOBOLEO’s interface could scale to knowledge models of a the semantic web recommendations, 2003.
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