In the secure domain computing environments, it is important to keep resources and information integrity from unauthorized access. Therefore, there is a strong demand on the access control for shared resources. In the past few years, Role-based Access Control (RBAC) has been introduced and offered a powerful means of specifying access control decisions. In this paper, an Object Oriented RBAC mo...

Modern distributed systems tend to be conglomerates of heterogeneous subsystems, which have been designed separately, by di erent people, with little, if any, knowledge of each other | and which may be governed by di erent security policies. A single software agent operating within such a system may nd itself interacting with, or even belonging to, several subsystems, and thus be subject to sev...

This paper examines the effect of open access policy on competition in network industries under uncertainty. Comparing a competition under an open access policy with a facility-based competition, we confirm that allowing access to an essential facility makes the timing of a follower’s entry earlier than that in a facility-based competition, irrespective of the level of access charge. Furthermor...

In this paper we are introducing the concept for the unified data access framework. The main aim of our work is to allow the unified data access on the international level for educational, commercial and security purposes. The idea of the unified access is important in the current days mostly for the national/international security, international labor policy, market restrictions or diseases pr...

In this paper we are introducing the concept for the unified data access framework. The main aim of our work is to allow the unified data access on the international level for educational, commercial and security purposes. The idea of the unified access is important in the current days mostly for the national/international security, international labor policy, market restrictions or diseases pr...

We present a theory for comparing the expressive power of access control models. The theory is based on simulations that preserve security properties. We perceive access control systems as state-transition systems and present two kinds of simulations, reductions and state-matching reductions. In applying the theory, we highlight four new results and discuss these results in the context of other...

Besides the well established access control models, Discretionary Access Control (DAC) and Mandatory Access Control (MAC), the policy neutral Role Based Access Control (RBAC) is gaining increasing attention. An important step towards a wide acceptance of RBAC has been achieved by the standardization of RBAC through the American National Standards Institute (ANSI). While the mandatory concept of...