Software Architectures for Scalable Ontology Networks

We describe an ongoing project to develop technology that will support collaborative construction and effective use of distributed large-scale repositories of highly expressive reusable ontologies. We are focusing on developing a distributed server architecture for ontology construction and use, representation formalisms that remove key barriers to expressing essential knowledge in and about ontologies, ontology construction tools, and tools for obtaining domain models for use in applications from large-scale ontology repositories. We are building on the results of the DARPA Knowledge Sharing Effort, specifically by using the Knowledge Interchange Format (KIF) as a core representation language and the Ontolingua system as a core ontology development environment.

Electronic Commerce Research and Applications, 2006

Semantic markup languages such as RDF (Resource Description Framework) and OWL (Web Ontology Language) are increasingly being used to externalize meta-data or ontologies about data, software and services in a declarative form. Such externalized descriptions in ontological format are used for purposes ranging from search and retrieval to information integration and to service composition . Ontologies could significantly reduce the costs of deploying, integrating and maintaining enterprise systems. The barrier to more wide-spread use of ontologies for such applications is the lack of support in the currently available middleware stacks used in enterprise computing. This paper presents our work on developing an enterprise-scale ontology management system that will provide APIs and query languages, and scalability and performance that enterprise applications demand. We describe the design and implementation of the management system that programmatically supports the ontology needs of enterprise applications in a similar way a database management system supports the data needs of applications. In addition, we present a novel approach to representing ontologies in relational database tables to address the scalability and performance issues. The state of the art ontology management systems are either memory-based or use ad-hoc solutions for persisting data, and so provide limited scalability.

2007

In this paper, an object-oriented model and a software environment for the management of OWL ontologies is presented. The object-oriented model allows a simple and complete representation of ontologies defined by using OWL DL profile. The software environment, called OWLET, implements this object-oriented model and provides a complete set of reasoning functions together with a graphical editor for the creation and modification of ontologies. OWLET can be very useful for realizing heterogeneous and distributed semantic systems where nodes differ for their capabilities (i.e., CPU power, memory size, …); in fact, it offers a layered reasoning API that allows to deploy a system where high power nodes take advantages of all the OWLET reasoning capabilities, medium power nodes take advantages of a limited set of OWLET reasoning capabilities (e.g., reasoning about individuals) and low power nodes delegate reasoning tasks to the other nodes of the system.

Proceedings of the International conference on …, 2002

Journal of Universal Computer Science, 2004

Knowledge management solutions relying on central repositories sometimes have not met expectations, since users often create knowledge ad-hoc using their individual vocabulary and using their own decentral IT infrastructure (e.g., their laptop). To improve knowledge management for such decentralized and individualized knowledge work, it is necessary to, first, provide a corresponding IT infrastructure and to, second, deal with the harmonization of different vocabularies/ontologies. In this paper, we briefly sketch the technical peer-to-peer platform that we have built, but then we focus on the harmonization of the participating ontologies.

There has been notable growth in the use of ontologies in knowledge management. This occurs because, with the use of ontologies, knowledge is shared and re-utilized efficiently and clearly among all the resources, whether a person or an application. However, for ontologies to establish confidence within an extremely competitive and flexible market, which is currently the case, they must be created in a way that is swift and with high credibility, portability and scalability. However, there is a noted lack of tools to aid knowledge specialists for the construction of a new ontology. For this purpose, this article presents a tool that enables the research of concepts in the knowledge entities represented in a given ontology, by importing multiple ontologies. As a result, knowledge can be exported and modeled into a new ontology. This project is based on the re-utilization of knowledge, with the aim of extending an ontology so as to make it adequate to its application.

Symbiotic relationships between semantic web and knowledge engineering, 2008

This paper describes a set of tools which allow the large number of ontologies available on the Semantic Web to be discovered and reused for other applications (both in the Semantic Web and by the larger knowledge engineering community). Firstly, these tools address the problem of finding an existing ontology, with given characteristics. Secondly, we discuss tools which allow the knowledge engineer to detect and repair errors which occur in the ontology's vocabulary (CleOn) or are related to logical coherency/inconsistency ( ...

We foresee that ontologies for interoperability are likely organized by a loosely linked network. In the case of digital libraries, the network is realized by a federation of ontologies where cross-links are made on demand. For the future, we plan to work on two extensions. The first one is to develop a new paradigm for synchronization of ontologies, called imitation. The second one is about publishing existing information sources by an ontology that is scalable in its size. Local parts of the ontology can be extended by global parts, which provide more meaning to the concepts. Finally, we are continuing our research on reverse engineering for integrating legacy components.

An ontology middleware system is defined, presented, and discussed in this paper. It includes number of features critical for the implementation of real-world knowledge management application: versioning, fine-grained access control, and meta-information. Important part of the research presented is the definition of proper models for support for each of these aspects. A security model with three levels of complexity is designed so to support proper management of the compromise between complexity and efficiency. The system presented is under development as a part of the On-To-Knowledge project where it is implemented as extension of the Sesame repository and allows management of knowledge represented in RDF(S)-based languages, including DAML+OIL. Although the implementation makes strong commitments to RDF(S), the definitions of the change tracking and security problems are of general KR importance. This paper is further development of the results reported in .