Collaborative ontology engineering: a survey <s> Wiki-based tools <s> This article describes the architecture and design principles of IkeWiki, a Semantic Wiki we developed at Salzburg Research. Outstanding features of IkeWiki are its support for collaborative knowledge engineering, its ease of use, its support for different levels of formalisation ranging from informal texts to formal ontologies, and its sophisticated, interactive user interface. While IkeWiki has been developed primarily as a tool for ontology engineering, it can be used in a variety of application scenarios. We briefly present some of these at the end of the article. <s> BIB001 </s> Collaborative ontology engineering: a survey <s> Wiki-based tools <s> We present OntoWiki, a tool providing support for agile, distributed knowledge engineering scenarios. OntoWiki facilitates the visual presentation of a knowledge base as an information map, with different views on instance data. It enables intuitive authoring of semantic content, with an inline editing mode for editing RDF content, similar to WYSIWYG for text documents. It fosters social collaboration aspects by keeping track of changes, allowing to comment and discuss every single part of a knowledge base, enabling to rate and measure the popularity of content and honoring the activity of users. Ontowiki enhances the browsing and retrieval by offering semantic enhanced search strategies. All these techniques are applied with the ultimate goal of decreasing the entrance barrier for projects and domain experts to collaborate using semantic technologies. In the spirit of the Web 2.0 OntoWiki implements an ”architecture of participation” that allows users to add value to the application as they use it. It is available as open-source software and a demonstration platform can be accessed at http://3ba.se. <s> BIB002
Wikis have received increasing attention in the Semantic Web community over the last 5 years 24 . This popularity is probably due to the user-friendliness of the core technology-a feature that is not necessarily characteristic to semantic applications-and to their focus on collaborative and community aspects. Existing semantic wikis primarily support the creation of semantic (instance) data expressed in Semantic Web languages such as RDF(S) or OWL; the development of the underlying ontologies is addressed-just as in the case of native ontology editors-mostly at implementation level, while the collaborative nature of wikis is assumed to inherently ease the consensus building within the engineering team. Exceptions from this are, for instance, the argumentation tool Cicero, which was previously mentioned in the context of the NeOn Toolkit, but also the tools that will be presented in the remainder of this section. IkeWiki BIB001 ) is a semantic wiki system for collaborative ontology engineering. It aims to formalize informal texts into formal ontologies using interactive user interfaces. Users can annotate pages and links between pages semantically in RDFS and OWL. These annotations are utilized for context-specific presentation of pages, advance querying and consistency checking as well as summarizing conclusions. IkeWiki offers a WYSIWYG editor using AJAX technology to communicate with the server and supports OWL-RDFS reasoning in order to derive implicit information from the facts stored in the knowledge base. Similar features are provided by OntoWiki 25 , which also includes an alternative visualization for geographical data in the form of Google Maps and calendars automatically generated from the semantic statements stored in the system with the purpose to ease the understanding of semantic information for non-experts BIB002 . Similarly to Cicero, the coefficientMakna system captures the ontology engineering discussions as instances of the argumentation ontology based on DILIGENT. It allows users to query data for monitoring the status of discussions, progress, and possible conflicts as well as reconstruct the rationale behind certain decisions. Usability is one of the main concerns of myOntology system  . To allow non-experts to participate in the process, myOntology focuses primarily on engineering lightweight ontologies, and implements several visualization techniques such as tag clouds and topic maps, and automatically builds links to Wikipedia and Flickr 26 for documentation purposes.