Validating Semistructured Data Using OWL

Web Semantics, 2005

Although the OWL Web Ontology Language adds considerable expressive power to the Semantic Web it does have expressive limitations, particularly with respect to what can be said about properties. We present SWRL (the Semantic Web Rules Language), a Horn clause rules extension to OWL that overcomes many of these limitations. SWRL extends OWL in a syntactically and semantically coherent manner: the basic syntax for SWRL rules is an extension of the abstract syntax for OWL DL and OWL Lite; SWRL rules are given formal meaning via an extension of the OWL DL model-theoretic semantics; SWRL rules are given an XML syntax based on the OWL XML presentation syntax; and a mapping from SWRL rules to RDF graphs is given based on the OWL RDF/XML exchange syntax. We discuss the expressive power of SWRL, showing that the ontology consistency problem is undecidable, provide several examples of SWRL usage, and discuss a prototype implementation of reasoning support for SWRL.

Encyclopedia of Information Science and Technology, Third Edition, 2015

2009

Despite similarities between the Web Ontology Language (OWL) and schema languages traditionally used in relational databases, systems based on these languages exhibit quite different behavior in practice. The schema statements in relational databases are usually interpreted as integrity constraints and are used to check whether the data is structured according to the schema.

Electronic Notes in Theoretical Computer Science, 2006

The rapid growth of the World Wide Web has resulted in more data being accessed over the Internet. In turn there is an increase in the use of semistructured data, which plays a crucial role in many web applications particularly with the introduction of XML and its related technologies. This increase in use makes the design of good semistructured data structures essential. The Object Relationship Attribute model for Semistructured data (ORA-SS) is a graphical notation for designing and representing semistructured data. In this paper, we demonstrate an approach to formally validate the ORA-SS data models in order to enhance the correctness of semistructured data design. A mathematical semantics for the ORA-SS notation is defined using the Z formal language, and further validation processes are carried out to check the correctness of the semistructured data models at both the schema and instance levels.

Proceedings of the Second International Conference on Web Information Systems Engineering

Semistructured data has become prevalent with the growth of the Internet. The development of new web applications that require efficient design and maintenance of large amounts of data makes it increasingly important to design "good" semistructured databases to prevent data redundancy and updating anomalies. However, it is not easy, even impossible, for current semistructured data models to capture the semantics traditionally needed for designing databases. In this paper, we show how an Object-Relationship-Attribute model for SemStructured data (ORA-SS) can facilitate the design of "good" semistructured databases. This is accomplished via the normalization of ORA-SS. An XML DTD or Schema generated from a normal form ORA-SS schema diagram has no undesirable redundancy, and thus no updating anomalies for the complying semistructured databases. The general design methodology and detailed steps for converting an ORA-SS schema diagram into a normal form ORA-SS schema diagram are presented. These steps can also be used as guidelines for designing semistructured databases using the ORA-SS model.

Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics), 2005

Description Logics (DLs) are a family of class (concept) based knowledge representation formalisms. They are characterised by the use of various constructors to build complex concepts from simpler ones, an emphasis on the decidability of key reasoning tasks, and by the provision of sound, complete and (empirically) tractable reasoning services. Although they have a range of applications (e.g., reasoning with database schemas and queries [1, 2]), DLs are perhaps best known as the basis for ontology languages such as OIL, DAML+OIL and OWL [3]. The decision to base these languages on DLs was motivated by a requirement not only that key inference problems (such as class satisfiability and subsumption) be decidable, but that "practical" decision procedures and "efficient" implemented systems also be available. That DLs were able to meet the above requirements was the result of extensive research within the DL community over the course of the preceding 20 years or more. This research mapped out a complex landscape of languages, exploring a range of different language constructors, studying the effects of various combinations of these constructors on decidability and worst case complexity, and devising decision procedures, the latter often being tableaux based algorithms. At the same time, work on implementation and optimisation techniques demonstrated that, in spite of the high worst case complexity of key inference problems (usually at least ExpTime), highly optimised DL systems were capable of providing practical reasoning support in the typical cases encountered in realistic applications [4]. With the added impetus provided by the OWL standardisation effort, DL systems are now being used to provide computational services for a rapidly expanding range of ontology tools and applications [5-9]. The increasing use of DL based ontologies in areas such as e-Science and the Semantic Web is, however, already stretching the capabilities of existing DL systems, and brings with it a range of research challenges.

Handbook on Ontologies, 2004

With the deep research of semantic Web, people are more and more concerned with the problem of representing and retrieving information content on the Web. The ontology language layer building on top of RDF schema is used to formally describe the meaning of ...

2005

One of the research fields which has recently gained much scientific interest within the database community are Peer-to-Peer databases, where peers have the autonomy to decide whether to join or to leave an information sharing environment at any time. Such volatile data nodes may appear shortly, collect or deliver some data, and disappear again. It even can not be assured that a peer joins the network ever again. In this paper we introduce a representation format fort both, schema and data information based on the Web Ontology Language OWL. According to the advantages of the Semantic Web we are thus able to represent and to transfer every schema and data component of a database to any partner, without having to define a data and schema exchange format explicitly.

Life Science …, 2012

Current World Wide Web means to display pages to end user, while the Semantic Web is a vision of a next-generation network focuses on "Meaning" instead of merely pasting arbitrary text on a page. An intelligent software agents use information to organize and filter data to meet the user's needs. DAML+OIL and Web Ontology Language OWL are the current environments to create Ontology over RDF and XML structures which are used to represent data intelligently among different Ontologies. To assure quality and accurateness in Ontologies in the early design stage, we used the Z-specification which is a formal language based on discrete mathematics such as predicate logic, sets, relations and functions to specify the behavior of Semantic Web. Further, we applied a transformation from schemas written in Z-specification to OWL. The formal specification is described and validated using Z/EVES tool. A fundamental goal of this research is to transform a verified and validated specification to OWL to design Ontologies.

Semantic Web is an extended form of World Wide Web in which efforts of Knowledge Engineers and Web Developers are combined to provide a semantic-rich web environment. Semantic Web application processes knowledge based on metadata of shared data sources available on Linked Open Data cloud.

Synthesis Lectures on the Semantic Web: Theory and Technology, 2017

Whether you call it the Semantic Web, Linked Data, or Web 3.0, a new generation of Web technologies is offering major advances in the evolution of the World Wide Web. As the first generation of this technology transitions out of the laboratory, new research is exploring how the growing Web of Data will change our world. While topics such as ontology-building and logics remain vital, new areas such as the use of semantics in Web search, the linking and use of open data on the Web, and future applications that will be supported by these technologies are becoming important research areas in their own right. Whether they be scientists, engineers or practitioners, Web users increasingly need to understand not just the new technologies of the Semantic Web, but to understand the principles by which those technologies work, and the best practices for assembling systems that integrate the different languages, resources, and functionalities that will be important in keeping the Web the rapidly expanding, and constantly changing, information space that has changed our lives. Topics to be included:

Lecture Notes in Computer Science, 2001

Semi-structured data has become prevalent with the growth of the Internet. The data is usually stored in a traditional database system or in a specialized repository. While many information providers have presented their databases on the web as semi-structured data, other information providers are developing repositories for new application. One such application is e-commerce, which is emerging as a major web-supported application assisting business transactions between multiple parties via the network and involving large amounts of data. Designing a \good" semi-structured database is increasingly crucial to prevent data redundancy, inconsistency and updating anomalies. In this paper, we propose a conceptual approach to design semi-structured databases. A conceptual layer which is based on the popular Entity-Relationship (ER) model is employed to remove anomalies and redundancies at the semantic level. An algorithm to map an ER diagram involving composite attributes weak entity types, recursive, n-ary and ISA relationship sets, and aggregations to a semi-structured schema graph (S3-Graph) used to represent semi-structured data is given. Our study reveals similarities between the S3-Graph and the hierarchical model and nested relations in that all have limitations in modeling situations with nonhierarchical relationships given their tree-like structures.

PhD Thesis, The University of Hong Kong, 2009

The nature of software applications is evolving very quickly in the past decade since the World Wide Web has been popularized. Some web applications are required to process large datasets which do not have well-defined structures. This has been challenging conventional data engineering methods. A conventional data engineering method typically requires that a system architect should have prior knowledge on what and how data are processed in an application so as to design a good database schema that optimizes data computations and storage. However, for a web application processing large-scale semi-structured and unstructured data, schema design tasks cannot always be handled totally by human, and need to be automated by software tools. In this thesis, I study the problems of schema computations for semi-structured XML data and unstructured RDF data. This thesis consists of two parts. In the first part, I investigate into the XML data interoperability problem of web services. To address this problem, I develop a formal model for XML schemas called Schema Automaton, and derive the computational techniques for schema compatibility testing and subschema extraction. In the second part, I investigate di?erent types of databases for RDF data. For one particular database type called property tables, I propose a new datamining technique namely Attribute Clustering by Table Load to automate the schema design for the database based on the underlying data patterns.

OWLED 2009, OWL: …, 2009

Abstract. The Ontology Definition Metamodel (ODM) defines a set of UML metamodels and profiles for development of RDF and OWL. The UML profiles in the ODM specification adapt UML notations to provide a form of visual representation for RDF and OWL. Recently, the ODM Revision ...

Lecture Notes in Computer Science, 2016

The Web Ontology Language OWL is a prominent ontology language for specifying ontologies. Although OWL ontologies are wellused for representing and reasoning about knowledge in various domains, they are sparsely studied for visual language specification. The work in this paper, therefore, explores OWL for visual language specification by specifying the concrete syntax of selected UML class diagram notations in an ontology. The selected diagram notations are specified as spatial configurations of primitive elements and qualitative base spatial relationships of Region Connection Calculus-8 (RCC-8). Furthermore, the automated reasoning features of ontology reasoners are investigated to verify the completeness and the correctness of the specification. The verification results indicate that the given specification needs to be revised to support applications to draw the selected notations. The value of such a specification in supporting a semantic diagram interpretation application is demonstrated using the automated instance classification feature of ontology reasoners.