Semantic Web Vision Research Articles

Editorial: Revisiting the (Machine) Semantic Web: The Missing Layers for the Human Semantic Web

THE Semantic Web has recently emerged as a new and highly promising context for knowledge and data engineering. Within an atmosphere of high expectations, many myths as well as many visions have exhibited a number of different approaches for the exploitation of the Semantic Web in both academia and industry. However, a struggling business reality requires a concrete strategy as well as the development of specific competencies from the knowledge and data engineering community in order to prove the value of the Semantic Web to society. For three years, we have undertaken a significant effort to cultivate the Semantic Web vision in the computer science, information systems, and Semantic Web communities through the Special Interest Group on Semantic Web and Information Systems of the Association for Information Systems (AIS, see http://www.aisnet.org [1], [8]). We have emphasized the benefits of the Semantic Web merits in different application contexts, including digital libraries, e-government, knowledge management, health care, and e-learning [3], [4], [5], [6]. One of the most fascinating aspects of our effort is the exchange of ideas with people that come from different disciplines, which has led us to arrive at the conclusion that the Semantic Web adoption requires the convergence of many different disciplines; this is illustrated in Fig. 1. It is more than obvious that, after an early stage of evolution, Semantic Web research has reached a first level of maturity. Most significantly, some “voices” of criticism or questioning for the pace of the change that Semantic Web brings to traditional knowledge and data engineering have initiated a new stream of innovations. The concept of semantics [2] and its capacity to support a new era of applications challenges the traditional perceptions for the never-ending journey of computing. Knowledge and data representation and retrieval require new conceptual models and the move to a human Semantic Web vision seems more timely than ever. After the initial enthusiasm and excitement following the launch of the Semantic Web vision, a time of significant problems, unexploited opportunities, and slow adoption followed. Knowledge and data engineering had to meet several diverse and high demanding requirements for the realization of the Semantic Web. In numerous international efforts as well as in various research and competence centers of the Semantic Web, there is now a continuous effort to reach the point for a real “take-off” of the Semantic Web. It looks like an entire research community is looking for the last step before the breaking of the “wall.” And, this wall is associated with all the inefficiencies of the traditional Web, and with a panacea for the solution of all the knowledgerelated performance gaps. For the past one and a half years, we have been working hard, with the support of a large number of reviewers, on the development of an excellent quality TKDE special issue on the Semantic Web. From the beginning, our motivation was based on a clear belief that the Semantic Web represents a key milestone for the knowledge and data engineering community. While the Semantic Web is often considered to be a machine-intensive/oriented theme, our key argumentation is that Semantic Web is a Human manifesto [7]. The fundamental social and political impact of the Semantic Web is derived from the fact that its underlying technology supports a shift of social interaction patterns from “knowledge push” to “knowledge pull” [7]. This includes the shift

Piggy Bank: Experience the Semantic Web inside your web browser

The Semantic Web Initiative envisions a Web wherein information is offered free of presentation, allowing more effective exchange and mixing across web sites and across web pages. But without substantial Semantic Web content, few tools will be written to consume it; without many such tools, there is little appeal to publish Semantic Web content. To break this chicken-and-egg problem, thus enabling more flexible information access, we have created a web browser extension called Piggy Bank that lets users make use of Semantic Web content within Web content as users browse the Web. Wherever Semantic Web content is not available, Piggy Bank can invoke screenscrapers to re-structure information within web pages into Semantic Web format. Through the use of Semantic Web technologies, Piggy Bank provides direct, immediate benefits to users in their use of the existing Web. Thus, the existence of even just a few Semantic Web-enabled sites or a few scrapers already benefits users. Piggy Bank thereby offers an easy, incremental upgrade path to users without requiring a wholesale adoption of the Semantic Web's vision. To further improve this Semantic Web experience, we have created Semantic Bank, a web server application that lets Piggy Bank users share the Semantic Web information they have collected, enabling collaborative efforts to build sophisticated Semantic Web information repositories through simple, everyday's use of Piggy Bank.

Aqualog: An Ontology-Driven Question Answering System for Organizational Semantic Intranets

The semantic web vision is one in which rich, ontology-based semantic markup will become widely available. The availability of semantic markup on the web opens the way to novel, sophisticated forms of question answering. AquaLog is a portable question-answering system whichtakes queries expressed in natural language and an ontology as input, and returns answers drawn from one or more knowledge bases (KBs). We say that AquaLog is portable because the configuration time required to customize the system for a particular ontology is negligible. AquaLog presents an elegant solution in which different strategies are combined together in a novel way. It makes use of the GATE NLP platform, string metric algorithms, WordNet and a novel ontology-based relation similarity service to make sense of user queries with respect to the target KB. Moreover it also includes a learning component, which ensures that the performance of the system improves over the time, in response to the particular community jargon used by end users.

Piggy Bank: Experience the Semantic Web Inside Your Web Browser

The Semantic Web Initiative envisions a Web wherein information is offered free of presentation, allowing more effective exchange and mixing across web sites and across web pages. But without substantial Semantic Web content, few tools will be written to consume it; without many such tools, there is little appeal to publish Semantic Web content. To break this chicken-and-egg problem, thus enabling more flexible information access, we have created a web browser extension called Piggy Bank that lets users make use of Semantic Web content within Web content as users browse the Web. Wherever Semantic Web content is not available, Piggy Bank can invoke screenscrapers to re-structure information within web pages into Semantic Web format. Through the use of Semantic Web technologies, Piggy Bank provides direct, immediate benefits to users in their use of the existing Web. Thus, the existence of even just a few Semantic Web-enabled sites or a few scrapers already benefits users. Piggy Bank thereby offers an easy, incremental upgrade path to users without requiring a wholesale adoption of the Semantic Web's vision. To further improve this Semantic Web experience, we have created Semantic Bank, a web server application that lets Piggy Bank users share the Semantic Web information they have collected, enabling collaborative efforts to build sophisticated Semantic Web information repositories through simple, everyday's use of Piggy Bank.

Building a semantic wiki

The semantic Web vision of a "unifying logical language that enables concepts to be progressively linked into a universal Web" is part of along lineage of dreams of a universal repository of ideas: from Diderot's universal encyclopedia in the 18th century to Vannevar Bush's Memex at the beginning of the computer age to Ted Nelson's Xanadu in the 1970s. However, the semantic Web's development so far has focused primarily on metadata and carefully designed data structures. To realize Berners-Lee's vision, the semantic Web must capture and represent content created every day by people without special training - such content includes blogs, emails, and discussion groups. Rhizome is an experimental, open source content management framework the author have created that can capture and represent informal, human-authored content in a semantically rich manner. Rhizome aims to help bring about a new kind of commons - one of ideas. This commons wouldn't comprise just a web of interlinked pages of content, as is the current World Wide Web, but a web of relationships between the underlying ideas and distinctions that the content implies: a permanent, universally accessible interlinking of content based on imputed semantics such as concepts, definitions, or structured argumentation.

Concept abduction and contraction for semantic-based discovery of matches and negotiation spaces in an e-marketplace

In this paper, we present a Description Logic approach – fully compliant with the Semantic web vision and technologies – to extended matchmaking between demands and supplies in a semantic-enabled Electronic Marketplace, which allows the semantic-based treatment of negotiable and strict requirements in the demand/supply descriptions. To this aim, we exploit two novel non-standard Description Logic inference services, Concept Contraction – which extends satisfiability – and Concept Abduction – which extends subsumption. Based on these services, we devise algorithms, which allow to find negotiation spaces and to determine the quality of a possible match, also in the presence of a distinction between strictly required and optional elements. Both the algorithms and the semantic-based approach are novel, and enable a mechanism to boost logic-based discovery and negotiation stages within an e-marketplace. A set of simple experiments confirm the validity of the approach.

Towards Semantic Web agents: Knowledge Web and AgentLink

This paper presents an overview on the role of agents in the Semantic Web, which was the topic of the AgentLink Technical Forum Group on ‘Semantic Web Agents’, aimed at fostering closer collaboration between the European communities working in these areas. The paper is structured in three main sections. In the first, we argue how agents are an essential component of the Semantic Web, then we provide a brief history, by no means comprehensive, of how the Semantic Web vision—that includes agents—has evolved over the past fifteen years. We then conclude, reporting on the topics presented and discussed during the Technical Forum.

On the Convergence of Formal Ontologies and Standardized E-Learning

Current efforts to standardize e-learning resources are centered on the notion of a learning object as a piece of content that can be reused in diverse educational contexts. Several specifications for the description of learning objects — converging in the LOM standard — have appeared in recent years, providing a common foundation for interoperability and shared semantics. At the same time, the Semantic Web vision has resulted in a number of technologies grounded in the availability of shared, consensual knowledge representations called ontologies. As proposed by several authors, ontologies can be used to provide a richer, logics-based framework for the expression of learning object metadata, resulting in the convergence of both streams of research towards a common objective. In this article, we address the practicalities of the representation of LOM metadata instances into formal ontologies, discussing the main technical and organizational issues that must be addressed for an effective integration of both technologies, and sketching some illustrative examples using modern ontology languages and a large knowledge base.

A framework for modeling and evaluating automatic semantic reconciliation

The introduction of the Semantic Web vision and the shift toward machine understandable Web resources has unearthed the importance of automatic semantic reconciliation. Consequently, new tools for automating the process were proposed. In this work we present a formal model of semantic reconciliation and analyze in a systematic manner the properties of the process outcome, primarily the inherent uncertainty of the matching process and how it reflects on the resulting mappings. An important feature of this research is the identification and analysis of factors that impact the effectiveness of algorithms for automatic semantic reconciliation, leading, it is hoped, to the design of better algorithms by reducing the uncertainty of existing algorithms. Against this background we empirically study the aptitude of two algorithms to correctly match concepts. This research is both timely and practical in light of recent attempts to develop and utilize methods for automatic semantic reconciliation.

Information retrieval and knowledge discovery utilising a biomedical Semantic Web

Although various ontologies and knowledge sources have been developed in recent years to facilitate biomedical research, it is difficult to assimilate information from multiple knowledge sources. To enable researchers to easily gain understanding of a biomedical concept, a biomedical Semantic Web that seamlessly integrates knowledge from biomedical ontologies, publications and patents would be very helpful. In this paper, current research efforts in representing biomedical knowledge in Semantic Web languages are surveyed. Techniques are presented for information retrieval and knowledge discovery from the Semantic Web that extend traditional keyword search and database querying techniques. Finally, some of the challenges that have to be addressed to make the vision of a biomedical Semantic Web a reality are discussed.

Semantic eBusiness

We define Semantic eBusiness as “an approach to managing knowledge for coordination of eBusiness processes through the systematic application of Semantic Web technologies.” Advances in Semantic Web-based technologies offer the means to integrate heterogeneous systems across organizations in a meaningful way by incorporating ontology—a common, standard, and shareable vocabulary used to represent the meaning of system entities; knowledge representation, with structured collections of information and sets of inference rules that can be used to conduct automated reasoning; and intelligent agents that collect content from diverse sources and exchange semantically enriched information. These primary components of the Semantic Web vision form the foundation technology for semantic eBusiness. The challenge for research in information systems and eBusiness is to provide insight into the design of business models and technical architecture that demonstrate the potential of technical advancements in the computer and engineering sciences to be beneficial to business and consumers. Semantic eBusiness seeks to apply fundamental work done in Semantic Web technologies to support the transparent flow of semantically enriched information and knowledge—including content and know-how—to enable, enhance, and coordinate collaborative eBusiness processes within and across organizational boundaries. Semantic eBusiness processes are characterized by the seamless and transparent flow of semantically enriched information and knowledge. We present a holistic view of semantic eBusiness that integrates emergent and well-grounded Semantic Web technologies to improve the current state of the art in the transparency of eBusiness processes.

A semantic retrieval of web documents using domain ontology

The Semantic Web vision offers the potential to express queries in a more semantic way. However, the unstructured nature of existing web documents, which lack semantics, proves to be a difficult task for such a query. To support this, the semantic information content of web documents needs to be specified in order to make the tangled information more structured and accessible. In this paper, we propose an approach meant to semantically query web documents using a natural language analysis technique and a domain specific ontology. Using both techniques, the tool gradually constructs the semantic document model of the documents retrieved from an existing search engine for each search session, which is represented as XML. The semantic model can then be semantically refined and browsed by the user.

Spinning the Semantic Web

From the quiet new born days of early 1990s, the World Wide Web has had an exponential growth in the last decade or so. From the original goal of sharing research resources, Web today portrays a virtual world spanning from research to entertainment and e‐commerce. This growth has necessitated substantial changes in the Web model. From the purely syntactic and relatively static framework of HTML, we have moved through DHTML and XML incorporating dynamicity and extensibility, and are now en route semantic frameworks starting with RDF. These allow Web documents to be comprehensible to machines (and not just to humans) allowing software agents to access and process such information on the Web. This leads us to semantic Web, and thus to a generation of Web applications based on Web services, adaptive content delivery, etc. Spinning the Semantic Web is based on papers presented in a seminar in Germany in 2000, and sketches the vario elements of semantic Web, the issues in realising it as well as some visions of the future. The stimulating forward to the book by Tim Berners‐Lee, recently Knighted and widely regarded as the father of the Web, portrays his vision of semantic Web. The chapters explore specific issues such as ontologies, schema languages, annotations, applications, etc. The chapters are largely unorganised and presented without any cross‐linking and most chapters use a fair amount of domain jargon. The book will be of value to those seriously interested in the field.

DAMLJessKB: a tool for reasoning with the Semantic Web

Fully realizing the Semantic Web vision will require practical tools. We believe that DAMLJessKB is one such tool. As more and more Web sites, network services, databases, and knowledge bases look to DAML as a de facto representation syntax, we hope that DAMLJessKB will become one in a suite of tools that let users truly leverage the shared semantics.

A conceptual architecture for semantic web enabled web services

Semantic Web Enabled Web Services (SWWS) will transform the web from a static collection of information into a distributed device of computation on the basis of Semantic technology making content within the World Wide Web machine-processable and machine-interpretable. Semantic Web Enabled Web Services will allow the automatic discovery, selection and execution of inter-organization business logic making areas like dynamic supply chain composition a reality. In this paper we introduce the vision of Semantic Web Enabled Web Services, describe requirements for building semantics-driven web services and sketch a first draft of conceptual architecture for implementing semantic web enabled web services.