This paper describes the work of the W3C Decisions and Decision-making Incubator 1, with the goal to identify requirements for a standard decision format, through a set of use cases, and to develop a first version of a potential standard format for representing decisions, fulfilling the requirements of the use cases and exploiting semantic web standards. Ongoing efforts include the identification and modelling of ‘decision patterns ’ and development of proof-ofconcept applications to validate assumptions and patterns.

Abstract. Reusing knowledge resources, specifically Ontology Design Patterns (ODPs), has became a popular technique within the ontology engineering field. Such a reuse allows speeding up the ontology development process, saving time and money, and promoting the application of good practices. Recently methods and tools to support the reuse of ODPs have emerged. In addition, the existence of detailed examples of real use cases that reuse ODPs favours the adoption and application of such methods. Thus, our objective in this paper is to show an example of how to apply a method for reusing ODPs during the development of a context ontology network to model context-related knowledge that allows adapting applications based on user context. Besides, in this paper we present the main drawbacks found during the application of the reuse method as well as some proposals to overcome them.

The high expressivity of the OWL ontology language often allows to express the same conceptualisation in different ways. A simple example is the difference between ‘class-centric ’ and ‘property-centric ’ modelling style, such that the same notion is modelled as a class in the former (e.g. ‘Purchase’) and an object property in the latter (e.g. ‘bought from’). Such heterogeneity is an obstacle to reusing ontologies in advanced semantic web scenarios. In particular, two ontologies modelled in different styles are difficult to match or to import to one another, as few matching systems support complex matching structures that bridge style heterogeneity, never mind considering schema merging and/or data migration. Furthermore, opting for a style when designing an ontology may have impact on the usability and performance of reasoners, as some features cause performance problems for certain reasoners. Semi-automatic transformation of the modelling style of existing ontologies, with the help of tools to be presented in the demo, will alleviate such problems. The whole tool suite consists of the PatOMat Transformation Framework