While complex systems have been studied now for more than two decades, there still is no agreement on what complexity actually is. This lack of a definition might be a problem when asking questions about the evolution of complexity. In this article criteria against which candidate measures of...

The implementation of usable security is particularly challenging in the growing field of Grid computing, where control is decentralised, systems are heterogeneous, and authorization applies across administrative domains. PERMIS, based on the Role-Based Access Control (RBAC) model, provides a...

There has, in recent years, been growing interest in Model Driven Engineering (MDE), in which models are the primary design artifacts and transformations are applied to these models to generate refinements leading to usable implementations over specific platforms. There is also interest in...

Existing access control systems are typically unilateral in that the enterprise service provider assigns the access rights and makes the access control decisions, and there is no negotiation between the client and the service provider. As access management systems lean towards being...

Context-awareness enables applications and services to better fulfil the needs of users by adapting to their situation and their preferences. However, the use of contextual information is complicated by privacy concerns. A subjects context is personal and needs to be regarded as sensitive....

Likelihood Function for a Simple Cardioid Sonobuoy Andrew R. Runnalls, University of Kent Published in IEE Proceedings Radar, Sonar and Navigation 153 [2006] pp. 417--26 ABSTRACT This paper considers the common sonobuoy configuration comprising two horizontal dipoles mounted orthogonally...

In this paper we describe how we have added support for dynamic delegation of authority that is enacted via the issuing of credentials from one user to another, to the XACML model for authorisation decision making. Initially we present the problems and requirements that such a model demands,...

If e-business contracts are to be widely used, they need to be supported by the IT infrastructure of the organizations concerned. This implies that the interactions between systems in different organizations must be guided by the contract and there must be sufficiently strong checks and balances...

As the health care industry enters the era of knowledge management it must place security at the foundation of the transition. Risks are pervasive to every aspect of information and knowledge management. Without secure practices that seek to avoid or mitigate the effects of these risks, how can...

In this paper we intend to show how the challenges of managing a Business Process Reengineering (BPR) project are consistent with the ones of a Systems Development project. As traditional management techniques were no longer appropriate in the changing business environment, companies employed...