Lyndon J. B. Nixon

Tuplespace-based computing for the semantic web: A survey of the state-of-the-art

Semantic technologies promise to solve many challenging problems of the present Web applications. As they achieve a feasible level of maturity, they become increasingly accepted in various business settings at enterprise level. By contrast, their usability in open environments such as the Web—with respect to issues such as scalability, dynamism and openness—still requires additional investigation. In particular, Semantic Web services have inherited the Web service communication model, which is primarily based on synchronous message exchange technology such as remote procedure call (RPC), thus being incompatible with the REST (REpresentational State Transfer) architectural model of the Web. Recent advances in the field of middleware propose ‘semantic tuplespace computing’ as an instrument for coping with this situation. Arguing that truly Web-compliant Web service communication should be based, analogously to the conventional Web, on shared access to persistently published data instead of message passing, space-based middleware introduces a coordination infrastructure by means of which services can exchange information in a time-and reference-decoupled manner. In this article, we introduce the most important approaches in this newly emerging field. Our objective is to analyze and compare the solutions proposed so far, thus giving an account of the current state-of-the-art, and identifying new directions of research and development.

Improving the accuracy of job search with semantic techniques

In this paper we introduce a prototype job portal which uses semantically annotated job offers and applicants. In our opinion, using Semantic Web technologies substantially increase market transparency, lower transaction costs and speed up the procurement process. However adding semantics is not a panacea for everything. We identify some outstanding problems in job search using the system and outline how the technique of query approximation can be the basis for a solution. Through an Industry-Research co-operation we are extending the prototype with these semantic techniques to demonstrate a more accurate job search.

Combining RDF Vocabularies for Expert Finding

This paper presents a framework for the reuse and extension of existing, established vocabularies in the Semantic Web. Driven by the primary application of expert finding, we will explore the reuse of vocabularies that have attracted a considerable user community already (FOAF, SIOC, etc.) or are derived from de facto standards used in tools or industrial practice (such as vCard, iCal and Dublin Core). This focus guarantees direct applicability and low entry barriers, unlike when devising a new ontology from scratch. The Web is already populated with several vocabularies which complement each other (but also have considerable overlap) in that they cover a wide range of necessary features to adequately describe the expert finding domain. Little effort has been made so far to identify and compare existing approaches, and to devise best practices on how to use and extend various vocabularies conjointly. It is the goal of the recently started ExpertFinder initiative to fill this gap. In this paper we present the ExpertFinder framework for reuse and extension of existing vocabularies in the Semantic Web. We provide a practical analysis of overlaps and options for combined use and extensions of several existing vocabularies, as well as a proposal for applying rules and other enabling technologies to the expert finding task.

Towards Semantic tuplespace computing: the Semantic web spaces system

In this paper we introduce Semantic Web Spaces, a middleware for coordinating knowledge processes on the Semantic Web. Co-ordination is an important aspect of any type of interaction between computer agents, but we find especially so on the Semantic Web in which the communication contains knowledge rather than data and correct inferences can only be made when the right knowledge is available at the right time. Because of this we have identified tuplespace computing as a relevant paradigm for agent communication on the Semantic Web and have prototypically realized a system based on a Linda-inspired coordination model and on core semantic technologies such as RDF, ontologies and reasoning.

Enabling real world semantic web applications through a coordination middleware

In a real world scenario Semantic Web applications must be capable to cope with the large scale, distributed, heterogeneous, unreliable and insecure environment of the World Wide Web if they are to truly represent added value to Web users. This includes issues of persistent storage, efficient reasoning, data mediation, scalability, distribution of data, fault tolerance and security. In this paper we present a coordination middleware for the Semantic Web and demonstrate its relevance to these vital issues for Semantic Web applications by elaborating a typical use case from the traffic management domain.

Towards a tuplespace-based middleware for the Semantic Web

The Semantic Web is about a Web which contains data which is machine-processable rather than human-interpretable. This makes new demands upon the Web architecture such as a standardized interface for access to this knowledge (how to interact), model and vocabulary-based mediation (how to understand) and semantic-based distribution (how to find). We present a middleware based on the concepts of co-ordination and space-based computing as a proposed part of the necessary Semantic Web architecture and outline its usage in the Web-based utilization of distributed knowledge.

Enabling the European Patient Summary through Triplespaces

One of the main items on the eHealth agenda of the European Community is the design and promotion of electronic patient summaries as an instrument to facilitate the pervasive delivery of healthcare, thus ensuring the right to patient mobility and increasing the productivity and quality of health service delivery. From a technical point of view this objective requires middleware technology which is able to cope with the stringent interoperability, multi-lingualism, security and privacy requirements arising in eHealth settings. In this paper we present triplespace computing, a coordination middleware for the semantic Web and demonstrate its relevance to the realization of the European patient summary infrastructure.

Towards a Component-Based Framework for Developing Semantic Web Applications

For those outside the research community, to develop Semantic Web applications entails real difficulty. This difficulty is due in part to the lack of usable approaches for planning Semantic Web solutions, even though Semantic Web tools have already reached industrial maturity. We propose here the Semantic Web Framework, a component-based framework for analysing rapidly the required components, the dependencies between them, and selecting existing solutions. This approach has been tested with a number of industrial partners, which justifies the effort made in this direction.

Enabling Collaborative eHealth through Triplespace Computing

The design and promotion of electronic patient summaries as an instrument to facilitate the pervasive delivery of healthcare is emerging as a key technology in eHealth solutions. From the technical point of view this requires powerful middleware systems supporting interoperability, multi-lingualism, security and patient privacy. In this paper we present a semantic coordination model and describe how it can be used to support pervasive access to electronic patient summaries.

A coordination model for the semantic web

The Semantic Web foresees a Web of machine-processable knowledge interacted with by clients in an operationalized manner. At Web scale, the coordination between clients will be vital for ensuring the success of their interactions. In this paper we consider how a coordination model for the Semantic Web would look, as a precursor to the design and implementation of Semantic Web Spaces, a middleware platform for real-world Semantic Web applications.