RDF-Based Peer-to-Peer Based Ontology Editing

Article excerpt

ASTRACT: The evolution of the Semantic Web has accelerated the need for ontologies. There is a need to build new ontologies and to extend and merge existing ontologies. To achieve this we need software tools to edit and build ontologies. Our paper describes software to develop a protocol for collaborative ontology editing based on RDF and using a Peer-to-Peer (P2P) networking architecture. The protocol allows for the implementation a voting mechanism embedded into the RDF data itself, using a mixed initiative design for notification. This is implemented as extensions to an ontology browser called ONTORAMA (1). The P2P approach is compared to the classic ontology editing approaches and the special requirements of the ontology editing environment are discussed. The protocol, design, implementation and architecture for ontology update are also elaborated.

Categories and Subject Descriptors

C.2.1 [Network Architecture and Design]; D.2.12 [Interoperability Web-based Services]

General Terms

Web services, Peer to peer network, Ontology

Keywords: Semantic web, Ontology, P2P Network architecture, RDF data, Network protocol

1. Introduction

The Semantic Web [4] is a vision of the Web where available data can be processed automatically by machines. In this vision, machines are able to retrieve and process data to make meaningful decisions and agents are able to communicate and negotiate to achieve sophisticated tasks set by users. To achieve this RDF was developed as a language that records sets of triples to describe any resource accessible on the Web. The power of RDF is that it maps the representation directly into a data model. This data model is simple but with a number of syntactic variations, most noticeably designed around an accommodation of XML syntax.

One of the main reasons for the appearance of RDF within the context of the Semantic Web is for the creation of ontologies--explicit specifications of conceptualizations specific to an application domain.

RDF gives an infrastructure to model such ontologies, which can be used to communicate available terminology to a user of a website or to enable semantic inter-operation between autonomous agents.

The paper is structured as follows. First, we present a literature survey that highlights ontology server tools and the difficulties associated with a client-server architecture for ontology management. Second, we elaborate on the task of ontology editing, what research in this area has achieved and how our design is adapted from previous successes in distributed collaboration. Second, we present an overview of P2P systems. Many of the features for sharing ontological content derive from other successful P2P file sharing systems. We characterize our work in the context of the feature space of well-known P2P systems with the additional (and special) requirement of ontology editing. Third, the high-level mechanisms for collaborative P2P ontology editing are developed. The idea of voting, via assertions and rejections on content, gives a mechanism to control ontology update and a principled approach to knowledge-based version control management. Since our solution is embedded within the ONTORAMA ontology browser, the fourth section of this paper describes ONTORAMA, its capabilities and limitations. We spent some time in the fifth section describing the implementation details: demonstrating the operation of the P2P editor in use cases. In future work, we will stress test the application to explore the bounds of its practical use as a distributed P2P system.

1. Background and Literature Survey

Our paper presents a P2P ontology editing environment based on the ontology browsing tool ONTORAMA. The prototype, derived from ONTORAMA, provides a basic editing capability and ontology visualization framework. Further, a P2P network protocol facilitates collaborative ontology editing. …