The paper presents revocation schemes in role-based access control models. We are particularly interested in two key issues: how to perform revocation and how to manage the revocation policy. We show how to deal with these two aspects in the delegation model based on the OrBAC formalism and its administration licence concept. This model provides means to manage several delegation types, such as...

• indemnities against claims of intellectual property infringement from third parties • requirements of consumer protection and antitrust legislation • obligations to redistribute source, and when they arise • enforceability of free software licences • layering and combining of licences • dual-licensing • licence incompatibility • software patent liability • contemporary developments in softwar...

This paper presents empirical evidence on the relationship between forest tenure and investment in silviculture. Silvicultural activities and expenditures on a large number of recently logged tracts in British Columbia, under four distinct forms of tenure, are assessed using a silvicultural investment model based on the conventional theory of capital. The empirical results indicate that silvicu...