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Many representative applications on the semantic web, including collaborative ontology building, partial ontology reuse, selective knowledge hiding and distributed data management, call for modular ontologies,. However, although OWL allows using owl:imports to connect multiple ontologies, its current semantics requires all involved ontologies to have a single global semantics, thus providing only...
With the growth of Internet and the fast development of semantic web technologies, the access and usage of information will become much more easier. However, the security of information gathering for both information suppliers and demanders is a critical issue. Policies determine the ideal behaviors for web concepts. The concepts of policy, policy languages and policy ontologies must be determined,...
Basic storage and querying of RDF data using a relational database can be done in a very simple manner. Such approach can run into trouble when used on large and complex data. This paper presents such data and several sample queries together with analysis of their performance. It also describes two possible ways of improving the performance based on this analysis.
Following software engineering approaches for the Semantic Web (SW) and also Hendler’s vision [3], I believe that the SW will not be a unique large complex Web, but it will be composed, mainly, of several small contextualized domain applications. These domain applications will be, in my opinion, Multi-Agent Systems (MAS) [5]. MAS have emerged as a promising approach for the development of information...
Web standards are currently seen as increasingly fragmented between colloquial XML, the Semantic Web, and Web Services. Semantic Web Services, while an immensely productive area of research, has yet to reach in-roads and a large user-base.We propose a minimalist, yet powerful, unifying framework built upon solid computational and philosophical foundations: Web Services are functions, ontologies are...
Ontologies represent a shared understanding of some domain of interest. Therefore, tools to develop ontologies have to support this sharing in some way. However, current tools lack support of this important aspect, if they tackle it at all. Beyond this, each interactive system cannot be limited to its utility but must also make sure that this is provided in a usable way. However, current ontology...
The Semantic Web presents the vision of a dynamically growing knowledge base that should allow users to draw on and combine distributed information sources specified in languages based on formal logic. Common users, however, were shown to have problems even with the simplest Boolean expressions [4]; the use of the logic formalism underlying the Semantic Web is beyond their understanding. So how can...
Updating an ontology that is in use may result in inconsistencies between the ontology and the knowledge base, dependent ontologies and applications/services. Current research concentrates on the creation of ontologies and how to manage ontology changes in terms of mapping ontology versions and keeping consistent with the instances. Very little work investigated controlling the impact on dependent...
By transforming the Web from a collection of documents to a collection of semantically rich data sources, the Semantic Web promises an unprecedented benefit of a global knowledge infrastructure. My PhD research will try to help make that happen at a global scale by doing the following proposed work: 1. Design and implement a highly scalable Semantic Web knowledge base system by exploiting modern...
Current solutions to data integration present many inconvenients. The bottleneck seems to be the impossible automation of the whole process. Human intervention will always be needed at some point, and the problem is to find where and how this intervention can be performed the most efficiently. In traditional mediator approaches the global schema and mappings between the global and local schemas are...
This thesis will address how to enable Triple Space Computing as a communication paradigm for Semantic Web Services. Currently, Semantic Web Services are following a message based communication paradigm. Triple Space Computing is envisioned as communication and coordination paradigm for Semantic Web Services which is an extension of tuple space computing to support RDF and then use it for communication...
Huge amounts of biological data are available online. To obtain needed information, biologists sometimes have to traverse different Web sources and combine their data manually. We introduce a system that can automatically interpret the structures of heterogeneous Web pages, extract useful information from them, and also transform them to machine-understandable pages for the Semantic Web, so that a...
The Semantic Web is an ecosystem of interaction among computer systems. The social web is an ecosystem of conversation among people. Both are enabled by conventions for layered services and data exchange. Both are driven by human-generated content and made scalable by machine-readable data. Yet there is a popular misconception that the two worlds are alternative, opposing ideologies about how the...
The notion of the Semantic Web can be coined as a Web of data when bringing database content to the Web or as a Web of enriched human-readable content when encoding the semantics of web-resources in a machine-interpretable form. It has been clear from the beginning that realizing the Semantic Web vision will require interdisciplinary research. At this the fifth ISWC, it is time to re-examine...
The virtual state is a metaphor meant to draw attention to the structures and processes of the state that are becoming increasingly aligned with the structures and processes of the semantic web. Semantic Web researchers understand the potential for information sharing, enhanced search, improved collaboration, innovation, and other direct implications of contemporary informatics. Yet many of the broader...
Ontology search and reuse is becoming increasingly important as the quest for methods to reduce the cost of constructing such knowledge structures continues. A number of ontology libraries and search engines are coming to existence to facilitate locating and retrieving potentially relevant ontologies. The number of ontologies available for reuse is steadily growing, and so is the need for methods...
An ontology alignment explicitly describes the relations holding between two ontologies. A system composed of ontologies and alignments interconnecting them is herein called a distributed system. We give three different semantics of a distributed system, that do not interfere with the semantics of ontologies. Their advantages are compared with respect to allowing consistent merge of ontologies, managing...
SPARQL is the W3C candidate recommendation query language for RDF. In this paper we address systematically the formal study of SPARQL, concentrating in its graph pattern facility. We consider for this study simple RDF graphs without special semantics for literals and a simplified version of filters which encompasses all the main issues. We provide a compositional semantics, prove there are normal...
Precisely identifying entities in web documents is essential for document indexing, web search and data integration. Entity disambiguation is the challenge of determining the correct entity out of various candidate entities. Our novel method utilizes background knowledge in the form of a populated ontology. Additionally, it does not rely on the existence of any structure in a document or the appearance...
We propose an approach that unifies browsing by tags and visual features for intuitive exploration of image databases. In contrast to traditional image retrieval approaches, we utilise tags provided by users on collaborative tagging sites, complemented by simple image analysis and classification. This allows us to find new relations between data elements. We introduce the concept of a navigation map,...
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