Constraints are an important aspect of role-based models. Several types of constraints, such as separation of duty constraints, cardinality constraints and temporal constraints have been identified in the literature. Although the specification of constraints has received significant research interest, there has been little work on the development of an efficient constraint enforcement model. In...

Location-based context-aware services for mobile users need to collaborate in disparate networks. Services come and go as the user moves and no central repository is available. The user’s personal information and service usage statistics need to be protected. To support service collaboration we propose a service infrastructure that relies on an event-based serviceoriented architecture. We imple...

ion des données : on peut définir des actions plus abstraites que lecture/écriture. Le modèle RBAC modélise le système informatique considéré en séparant les entités actives des entités passives. Les entités actives correspondent aux utilisateurs du système et les entités passives correspondent aux objets du système. Au contraire du modèle de LaPadula, qui associe des niveaux de sécurité aux di...

This paper consists of a survey of current, and past, work on program transformation for the purpose of optimization. We first discuss some of the general methodological frameworks for program modification, such as analogy, explanation based learning, partial evaluation, proof theoretic optimization, and the unfold/fold technique. These frameworks are not mutually exclusive, and the latter, unf...

We exhibit the benefits of using formal methods for constructing and documenting component software. Formal specifications provide concise and complete descriptions of black-box components and, herewith, pave the way for full encapsulation. Specifications using abstract statements scale up better than prepostconditions and allow for ‘relative’ specifications because they may refer to other comp...

We introduce a condition for the verification of properties in component-based systems that allows for components with variants and hence supports reusability. Thereby, the architecture of the system and behavior equivalences between the components are exploited in order to cope with the state space explosion problem. We use the model of interaction systems as the component model and extend it ...

Early design and validation of service-oriented applications is hardly feasible due to their distributed, dynamic, and heterogeneous nature. In order to support the engineering of such applications and discover faults early, foundational theories, modeling notations and analysis techniques for component-based development should be revisited. This paper presents a formal framework for coordinate...

Abstract rules and specific fact situations interact in a highly complex fashion in engineering ethics, a weak analytic domain. In such domains, the construction of arguments or explanations does not rely on formal methods or proofs. Rather, experienced reasoners appear to address problems by applying ethical principles using a variety of techniques. In our study of a national engineering socie...

It is widely agreed that building correct fault-tolerant systems is very difficult. To address this problem, this paper introduces a new model-based approach for developing masking fault-tolerant systems. As in component-based software development, two (or more) component specifications are developed, one implementing the required normal behavior and the other(s) the required fault-handling beh...

A brief overview of the requirements engineering, its history, and state of practice are given. A semi-formal method to structure the behavioral requirements for realtime embedded systems is presented. This method is based on a set of forms that contain both informal textbased descriptions and formally defined language constructs. After documentation of requirements into these forms, an algorit...