The wireless revolution has enabled a new generation of applications for nomadic users. In this work we propose a new paradigm for the creation of games based on virtual worlds that are hosted on mobile devices. Each time mobile devices “get in touch”, their virtual worlds have the opportunity to interact. This form of interaction is based on the remote control of a subset of the agents that po...

In this paper, we develop a new paradigm for access control and authorization management, called task-based authorization controls (TBAC). TBAC models access controls from a task-oriented perspective than the traditional subject-object one. Access mediation now involves authorizations at various points during the completion of tasks in accordance with some application logic. By taking a taskori...

Random convex programs (RCPs) are convex optimization problems subject to a finite number N of random constraints. The optimal objective value J∗ of an RCP is thus a random variable. We study the probability with which J∗ is no longer optimal if a further random constraint is added to the problem (violation probability, V ∗). It turns out that this probability rapidly concentrates near zero as ...

Multimedia interaction between users usually takes the form of conferences. We propose a taxonomy of multimedia conferencing, and develop a model that can support most types of collaborative interactions. The model provides sophisticated features such as access control with respect to diierent media streams, exibility to use multiple media channels to participate in multiple conferences simulta...

Cloud Computing is an emerging paradigm to offer on demand IT services to customers. The access control to resources located in the cloud is one of the critical aspects to enable business to shift into the cloud. Some recent works provide access control models suitable for the cloud, however there are important shortages that need to be addressed in this field. This work presents a step forward...

Developing concurrent applications is not a trivial task. As programs grow larger and become more complex, advanced concurrency control mechanisms are needed to ensure that application consistency is not compromised. Managing mutual exclusion on a per-object basis is not sufficient to guarantee isolation of sets of semantically-related actions. In this paper, we consider ‘atomic blocks’, a simp...

Every organisation today wants to adopt cloud computing paradigm and leverage its various advantages. Today everyone is aware of its characteristics which have made it so popular and how it can help the organisations focus on their core activities leaving all IT services development and maintenance to the cloud service providers. But it’s the security concerns that customers have which are prev...

We propose to extend the synchronous language Esterel by coordination primitives and by an asynchronous parallel composition operation on the level of modules. This is to program reactive systems such that subsystems may proceed at their own speed without enforcing a global knowledge of time. We intend is to stick with the synchronous language paradigm as close as possible since we aim for prop...

Most existing universal approximation results for fuzzy systems are based on the assumption that we use t conorms and t conorms to represent and and or Yager has proposed to use within the fuzzy system modeling paradigm more general operations based on uninorms In this paper we show that the universal approximation property holds for an arbitrary choice of a uninorm

Over the last three decades, the certainty equivalence principle has been the fundamental paradigm in the design of adaptive control laws. It is well known, however, that for general control criterions the performance achieved through its use is strictly suboptimal. In order to overcome this difficulty, two different approaches have been proposed: i) the use of cost-biased parameter estimators;...