Modelling the compatibility of licenses

Abstract

Web applications facilitate combining resources (linked data, web services, source code, documents, etc.) to create new ones. For a resource producer, choosing the appropriate license for a combined resource is not easy. It involves choosing a license compliant with all the licenses of combined resources and analysing the reusability of the resulting resource through the compatibility of its license. The risk is either, to choose a license too restrictive making the resource difficult to reuse, or to choose a not enough restrictive license that will not sufficiently protect the resource. Finding the right trade-off between compliance and compatibility is a difficult process. An automatic ordering over licenses would facilitate this task. Our research question is: given a license li, how to automatically position li over a set of licenses in terms of compatibility and compliance? We propose CaLi, a model that partially orders licenses. Our approach uses restrictiveness relations among licenses to define compatibility and compliance. We validate experimentally CaLi with a quadratic algorithm and show its usability through a prototype of a license-based search engine. Our work is a step towards facilitating and encouraging the publication and reuse of licensed resources in the Web of Data.