@techreport{TR-IC-01-13,
  number = {IC-01-13},
  author = {Jacques Wainer and Paulo Barthelmess and Akhil Kumar},
  title = {{W-RBAC} - A Workflow Security Model Incorporating Controlled Overriding of Constraints},
  month = {October},
  year = {2001}, 
  institution = {Institute of Computing, University of Campinas},
  note = {In English, 27 pages.
    \par\selectlanguage{english}\textbf{Abstract}
      This paper presents a pair of role-based access control models
      for workflow systems, collectively known as the W-RBAC model.
      The models described here contains both static and dynamic
      (history based) constraints, which is integrated with a workflow
      system. The W0-RBAC model describes our concept of dynamic
      constrains, and the integration of the access control system
      with the workflow. The W1-RBAC model extends the W0-RBAC model
      by allowing for a controlled overriding of constraints, which we
      argue are necessary in workflow applications in order to cope
      with exceptional situations. Finally we discuss a Prolog
      implementation of the access control models.
  }
}