题目：Modelling the execution of workflows under role-based authorisation control
报告人：何黎刚博士 英国沃里克大学
地点：东五楼二楼210学术报告厅
时间：4月7日晚上8：00

报告摘要：
　　When investigating performance of running applications in paralleland distributed systems, we often only take resource allocation into account,assuming that computational resources will accept the applications and executethem to completion once the resources are available. In reality, especially in Gridor e-business environments, security policies may be implemented in individualorganisations. Therefore, the performance of executing applications under security policies needs to be investigated. Authorisation control, which specifies who is allowed to perform which tasks at what time, is one of the most important security considerations in the distributed systems such as Grids. Role-Based Access Control (RBAC), under which the users are assigned to certain roles while the roles are associated with prescribed permissions, is among most popular authorisation control mechanisms. This work presents a mechanism to model the performance of running workflows under the RBAC control. Color timed Petri-net formalism is applied to construct the model. Various authorisation constraints are modeled, including temporal constraints, cardinality constraints, binding of duty and separation of duty constraints, etc. In this work, the model composition is modularized so that it is easy to apply the presented mechanism to model the authorisation and execution of complex workflows. A Petri-net simulation tool, CPN-Tool, is utilised to implement the developed mechanism and simulate the constructed model. Simulation experiments can be conducted to evaluate the impact of authorisation policies on the execution performance of the workflows.

报告人简介：
Dr. Ligang He graduated from Huazhong University of Science and Technology with the Bachelor and the Master degree, and from the University of Warwick, United Kingdom, with the PhD degree. He then did the postdoctoral research at the Cambridge University. He is now Assistant Professor in the Department of Computer Science at the University of Warwick.