Semantic Web Best Practices and Deployment Working Group - Publications
Notes
- 1 translation for Defining N-ary Relations on the Semantic Web
- русский
In Semantic Web languages, such as RDF and OWL, a property is a binary relation: it is used to link two individuals or an individual and a value. However, in some cases, the natural and convenient way to represent certain concepts is to use relations to link an individual to more than just one individual or value. These relations are called n-ary relations. For example, we may want to represent properties of a relation, such as our certainty about it, severity or strength of a relation, relevance of a relation, and so on. Another example is representing relations among multiple individuals, such as a buyer, a seller, and an object that was bought when describing a purchase of a book. This document presents ontology patterns for representing n-ary relations in RDF and OWL and discusses what users must consider when choosing these patterns.
The RDF and OWL Recommendations use the simple types from XML Schema. This document addresses three questions left unanswered by these Recommendations: Which URIref should be used to refer to a user defined datatype? Which values of which XML Schema simple types are the same? How to use the problematic xsd:duration in RDF and OWL? In addition, we further describe how to integrate OWL DL with user defined datatypes (in appendix B).
- 1 translation for A Semantic Web Primer for Object-Oriented Software Developers
- русский
Domain models play a central role throughout the software development cycle, from requirements analysis to design, through implementation and beyond. As such, great progress has been made in the consistent use of models throughout this process. Modern software development tools with support for the UML and code generation as well as Model-Driven Architectures allow for developers to synchronize and verify technical implementation with user requirements using models. However, the reusability of domain models is often limited because they are, by definition, domain specific and only take into consideration abstractions needed to make possible a solution within the confines of their own individual problem space. But the Web is broader than that and provides a multidimensional solution space capable of referencing an almost limitless set of domains. While much of our software becomes increasingly embedded in the Web, our development processes do not fully exploit the potential of model reuse from the Web yet. This note therefore introduces Semantic Web languages such as RDF Schema and OWL, and shows how they can be used in tandem with mainstream object-oriented languages. We show that the Semantic Web can serve as a platform on which domain models can be created, shared and reused.
The Resource Description Framework (RDF) is a model developed by the W3C for representing information about resources in the World Wide Web. Topic Maps is a standard for knowledge integration developed by the ISO. This document contains a survey of existing proposals for integrating RDF and Topic Maps data and is intended to be a starting point for establishing standard guidelines for RDF/Topic Maps interoperability.
Modelling various descriptive "features" (also known variously as "qualities", "attributes" or "modifiers") is a frequent requirement when creating ontologies. For example: "size" may describe persons or other physical objects and be constrained to take the values "small", "medium" or "large"; rank may describe military officers and restricted to a specific list of values depending on the military organisation. In OWL such descriptive features are modelled as properties whose range specifies the constraints on the values that the property can take on. This document describes two methods to represent such features and their specified values: 1) as partitions of classes; and 2) as enumerations of individuals. It does not discuss the use of datatypes to represent lists of values.
This document addresses the issue of using classes as property values in OWL and RDF Schema. It is often convenient to put a class (e.g., ) as a property value (e.g., topic or book subject) when building an ontology. While OWL Full and RDF Schema do not put any restriction on using classes as property values, in OWL DL and OWL Lite most properties cannot have classes as their values. We illustrate the direct approach for representing classes as property values in OWL-Full and RDF Schema. We present various alternative mechanisms for representing the required information in OWL DL and OWL Lite. For each approach, we discuss various considerations that the users should keep in mind when choosing the best approach for their purposes.