Neologism: Easy Vocabulary Publishing
Cosmin Basca1 , Stéphane Corlosquet1 , Richard Cyganiak1 , Sergio Fernández2
and Thomas Schandl11Digital Enterprise Research InstituteNational Univerisity of Ireland, Galway
Galway, Ireland{firstname.surname}@deri.org
2
Fundación CTIC
Gijón, Asturias, Spain
sergio.fernandez@fundacionctic.org

Abstract. Creating, documenting, publishing and maintaining an RDF
Schema vocabulary is a complex, time-consuming task. This makes vocabulary maintainers reluctant to evolve their creations quickly in response to user feedback; it prevents use of RDF for casual, ad-hoc data
publication about niche topics; it leads to poorly documented vocabularies, and contributes to poor compliance of vocabularies with bestpractice recommendations. Neologism is a web-based vocabulary editor
and publishing system that dramatically reduces the time required tocreate, publish and modify vocabularies. By removing a lot of pain fromthis process, Neologism will contribute to a generally more interesting,relevant and standards-compliant Semantic Web.

1Introduction

Anyone who wants to publish information as RDF on the Semantic Web firstfaces the choice which RDF Schema vocabulary or OWL ontology to use. Someareas, such as social networks (FOAF), online communities (SIOC) or general
document metadata (DC) are covered by established vocabularies. Outside ofthese domains, registries like SchemaWeb3 and search services like Falcons Concept Search4 assist in the task of finding vocabularies for niche topics, but what
they find might be of insufficient quality, or might not cover all required terms,
and at present many areas of interest are not covered by any vocabulary at all.
In summary, most efforts to publish information on the Semantic Web firstrequire an effort to create, extend or modify an RDF Schema vocabulary or OWL
ontology. But this is a complex and time-consuming task in itself. It involves:– Creating the formal specification of the vocabulary in RDFS or OWL,
– writing documentation that is clear and helpful for users of the ontology,– keeping both documents in sync as the vocabulary evolves,34

http://www.schemaweb.info/
http://iws.seu.edu.cn/services/falcons/conceptsearch/

– archiving older versions of the documents,– defining and maintaining mappings to related vocabularies,– configuring the web server in accordance with W3C best practices [3].
In this paper we present an online vocabulary editor and publishing system
based on Drupal5 , implemented in PHP and ActionScript, which will support
vocabulary authors in the tasks above and thereby dramatically reduce the timerequired to create, publish and modify vocabularies. The work presented in thispaper is in progress.

2

The value of vocabularies

We define vocabularies as simple, “lightweight” ontologies, such as FOAF, DC,
SIOC and SKOS. They usually comprise less than 50 terms. Expressivity is limited to RDF Schema plus selected OWL features, e.g. inverse functional properties and class disjointness. Their value is in providing common terminology
for exchanging information between programs. The actual information is in theRDF instance data that is expressed with the vocabulary’s terms, while in more
complex ontologies, the actual information lies in the definitions of the classes
and properties. A vocabulary is created by publishing a description of its terms
in natural using HTML or formal using RDFS/OWL language. Since classes
and properties are identified by URIs, it is considered a good practice to makethese URIs resolvable [2, 3]. This enables clients to look up definitions of thevocabulary terms, with the following benefits:– Information publishers can refer to a specification. This is important to create interoperability around a vocabulary. The top ten most popular vocabularies of 20066 all have a such a specification.
– RDF-aware tools such as data browsers (e.g. Tabulator [2]), SPARQL querybuilders and RDF instance editors can use the formal specification to improvethe user experience, e.g. by showing friendlier labels and comments, listingavailable terms and providing widgets appropriate to a property’s data type.
– Inference can be performed to increase recall when performing queries orlookups against RDF data, which is especially useful when terms are mapped
to other vocabularies. Systems that use such techniques are the Tabulator
data browser [2] and the Sindice semantic lookup index [6].

3Current approaches to vocabulary publishing

Vocabulary maintenance with text editors and custom scripts. Many popularvocabularies such as FOAF and SIOC are maintained by a process involving
hand-authoring of RDF and HTML files and custom scripts, e.g. SpecGen7 . Often, complex custom Apache configurations are employed to follow best practices
regarding content negotiation, MIME types and resolvable URIs [3].
5

http://drupal.org/
http://ebiquity.umbc.edu/resource/html/id/196/
7
http://sioc-project.org/specgen6Fig. 1. A vocabulary page in Neologism, as it appears to an authenticated user.

Offline ontology editors. OWL ontology editors such as Protégé [5], TopBraid
Composer8 and SWOOP9 can be used to create the formal specification of a vocabulary. While being great tools for knowledge engineering professionals, theseapplications have a steep learning curve and they intimidate casual users. Theyuse a file-based, offline model, where ontology files are stored on the local user’scomputer. Remote publishing, if supported at all, is an after-thought.
Web-based systems. OntoWiki [1] provides basic ontology editing, but its main
focus is the display and editing of RDF instance data. MyOntology [7] focuseson collaborative editing in a larger community, in the hope of creating richknowledge bases, while creation of simple vocabularies typically does not involve
many collaborating users. Knoodl10 is a hosted service with strong community
features and an easy-to-use vocabulary editor, but it does not publish createdvocabularies with resolvable URIs or according to best-practice guidelines.
Areas for improvement. We identify four points where we can simplify the process: (i) Instant web-based publishing instead of file-based offline editing. (ii)
Focus on a limited subset of RDFS and OWL. (iii) No instance editing or browsing. (iv) Handling of HTTP details like URI management, content negotiation
and redirects within the web-based application.

4Easier vocabulary publishing with Neologism

Neologism11 is a web-based vocabulary editor and publishing platform designed
to address these issues. It is currently being implemented and will soon be released as an open-source project. This section presents Neologism’s current state.
Public interface. To non-authenticated users on the Web, Neologism presents
a very simple interface: a homepage that lists one or more vocabularies, andfor each of them a vocabulary page containing some general information about
the vocabulary (Figure 1), followed by the descriptions of all its classes andproperties.
8

http://www.topbraidcomposer.com/
http://www.mindswap.org/2004/SWOOP/
10
http://knoodl.com/
11
http://neologism.deri.ie/
9Fig. 2. A form for editing a class.

Editor. After a vocabulary maintainer logs in, additional links become visible on
the vocabulary page and allow adding new terms, as well as editing of existingterms. Terms are created and edited through a web form (Figure 2). The form
allows entry of an ID (to become part of the term’s URI), label, comment,subclasses, subproperties, domain, range, disjoint classes, inverse properties, andmarking a property as inverse functional. Authenticated users can also create
new vocabularies and modify the vocabulary metadata.
Overview diagram. The vocabulary page provides access to a diagram that shows
the vocabulary’s classes and their relationships (Figure 3). The vocabulary
maintainer can arrange the diagram into a sensible layout and then save its
current state which will henceforth be shown to all users.
RDFS output, URIs and content negotiation. The URIs identifying classes andproperties are always generated by appending the hash character and the term’s
ID to the URI of the vocabulary page. This makes sure that the vocabulary
page is returned when these URIs are resolved. HTTP requests to the vocabulary
page are subject to content negotiation. Web browsers will see the HTML variant
shown in Figure 1. RDF-aware clients will receive the RDFS/OWL specification,either in RDF/XML or N3 syntax. In a nutshell, Neologism publishes standardscompliant vocabularies on the Web without requiring any additional effort on
the part of vocabulary maintainers.
Implementation. Neologism is implemented in PHP as a Drupal module. Drupal
reduces development time by providing many features for free, such as accountmanagement. It also makes integration with a larger Drupal-based site very easy,
for example to provide a news blog and discussion forum for each vocabulary. All

Fig. 3. The vocabulary overview diagram.

data is stored in a MySQL database. RAP12 is used to serialize RDF/XML andN3. The PHP Content Negotiation library13 is used instead of the usual Apacherules to implement content negotiation, and Vapour14 was used to validate itscorrectness. The overview diagram is implemented using Adobe Flex and codedin ActionScript; the ObjectHandles and Tweener libraries are used for animationand object handling.

5Future Work

Hosted Neologism service. Currently, vocabulary maintainers must install Neologism on their own webspace. A central hosted service, which could be easily
built on the Drupal platform, would remove this barrier.
Branching and revision tracking. Neologism does not yet offer revision control.
Some desirable features for vocabulary revision control are: archival of all priorversions; grouping of several small edits into a single version to avoid putting
the vocabulary into an inconsistent intermediate state; publishing changes as adraft before accepting them as a new version.
12

http://www4.wiwiss.fu-berlin.de/bizer/rdfapi/
http://ptlis.net/source/php-content-negotiation/14
http://vapour.sourceforge.net/
13

Plugin system. We intentionally kept the set of supported class and property
annotations small to simplify the user experience, and don’t support many possible further annotations, such as OWL cardinality constraints, plural and inverse labels15 , multilingual labels or associating Fresnel lenses [4] with classes
and properties. Such additional annotations could be supported through plugins
that are installed by vocabulary maintainers.
Consistency checking. Neologism doesn’t check the created vocabulary for consistency. This can become an issue when a vocabulary is integrated with several
external vocabularies. A solution could be the integration of an external reasoning service that performs consistency checks and is invoked through an API overthe Web.

6ConclusionWe have shown a web-based vocabulary publishing system that simplifies theprocess of creating, publishing and maintaining RDF vocabularies by (i) instant
web-based publishing, (ii) focus on a limited subset of RDFS and OWL, (iii)
avoiding instance editing or browsing, and (iv) handling URI management andHTTP content negotiation. We hope that the presented system will encourage
the creation of new vocabularies and thereby contribute to a generally moreinteresting, relevant and standards-compliant Semantic Web.

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http://www.wasab.dk/morten/2004/03/label