Complex control systems are heterogeneous, in the sense of discrete computer-based controllers interacting with continuous physical plants, regular data sampling interleaving with usually irregular communication and user interaction, and multilayer and multimode control laws. This heterogeneity imposes great challenges for control system design technologies in terms of end-to-end control perfor...

Authorization control has been well studied for years, and there are quite a few theories and techniques available for handling access control for a single or a centralized system. However unique and challenging security issues concerning business collaboration in the context of service oriented computing (SOC) have arisen due to the dynamic and loosely coupling nature of the environment in whi...

ABSI'RACI' Real-time control systems with a subset of processes subject to deadlines are investigated. The structure and the perfoImance of a class of such systems. namely the data acquisition and analysis systems are analyzed in case of procedure oriented as well as in the case of message oriented design. A methodology for system modeling and the approximations needed are discussed.

A long-term research goal for Aspect-Oriented Programming is the modular verification of aspects such that safe evolution and reuse is facilitated. However, one of the fundamental problems with verifying aspect-oriented programs is the inability to determine the effect of the weaving process on the control flow of the program, and thus on the state of the system and subsequently the properties ...

Specifying, enforcing and evolving access control policies is essential to prevent security breaches and unavailability of resources. These access control design concerns impose requirements that allow only authorized users to access protected computer-based resources. Addressing these concerns in a design results in the spreading of access control functionality across several design modules. T...

We consider the use of aspect-oriented techniques as a flexible way to deal with security policies in distributed systems. Recent work suggests to use aspects for analysing the future behaviour of programs and to make access control decisions based on this; this gives the flavour of dealing with information flow rather than mere access control. We show in this paper that it is beneficial to aug...

In this paper, we present new pointcuts and primitives to Aspect-Oriented Programming (AOP) languages that are needed for systematic hardening of security concerns. The two proposed pointcuts allow to identify particular join points in a program’s control-flow graph (CFG). The first one is the GAFlow, Closest Guaranteed Ancestor, which returns the closest ancestor join point to the pointcuts of...

Actors in our general framework for secure systems can exert four types of control over other actors’ systems, depending on the temporality (prospective vs. retrospective) of the control and on the power relationship (hierarchical vs. peering) between the actors. We make clear distinctions between security, functionality, trust, and distrust by identifying two orthogonal properties: feedback an...