The healthcare system is a real example of a distributed collaborative system, which aims to improve the patient's healthcare. The most important requirements of the healthcare system are the sensitivity of the medical data processed, large numbers of medical and para-medical interveners, as well as the medical treatment activity is a non-static process. Protecting data from unauthorized access and data sharing security in the healthcare environment is a critical process that influences system credibility. To achieve this goal and to meet the requirements of the healthcare system, the authors propose an extended Attribute-Based Access Control (ABAC) model by introducing the medical activity concept. This article defines the medical activity concept as an abstraction of collaboration in a care unit, defined by a medical activity purpose, in which the collaborators (or actors) realize their tasks in order to achieve the treatment purpose. The current access control model ABAC and these variants do not take into account the (business process) activity concept in the decision mechanism. In this paper, the authors propose a new access control model, called Medical-Activity-Attribute-Based Access Control (MA-ABAC), which can effectively enhance the security for healthcare system and produce more perfect and flexible mechanism of access control; order to strongly respond to the requirements of the distributed healthcare environment.

Various techniques have been proposed to achieve good QoS for diverse application types at network nodes. In order to supply the various QoS requirements for different kinds of applications, new scheduling policies need to be developed and evaluated. Many scheduling techniques have been proposed to respond to the temporal requirements of real-time flows. We propose a new scheduling Hierarchical Hybrid EDF/FIFO for network service, which considers the real time flow have higher priority to service. The technique uses the algorithm Earliest Deadline First (EDF) because the optimality of this algorithm has been proved for a number of criteria. However, this algorithm knows a complexity that increases with the size of queue. Our approach for scheduling is nonpreemptive and based in two queues. The first queue for real time flow (class-1) combines the two policies EDF and First in First out (FIFO) to reduce the complexity of EDF. The second queue for non real time flow (class-2) is scheduled by FIFO policy. The work complexity of our approach is less or equal than O(n log 2 n) with n is the length of the hierarchical queue. The simulation results underline the effectiveness of this approach.

Scheduling real time and non real time packets at network nodes has an important impact by reducing theprocessing overhead, queuing delay and response time. Most of the existing packet scheduling algorithmsused in network based on First-In First-Out (FIFO), non-preemptive priority, and preemptive priorityscheduling. However, these algorithms incur a large processing overhead, queuing delay and responsetime and are not dynamic to the data traffic changes. In this paper, we present a new hierarchicalscheduling algorithm to assign priority, Hierarchical Hybrid EDF/FIFO which can not only serve the realtime traffic but also provide best effort service to non real time traffic. To examine our approach forscheduling, we realized our analytical study to express the worst case queuing delay and the worst caseresponse time for different traffics. The simulation results showed that the Hierarchical hybrid EDF/FIFOachieved the minimum packet delay and adequate loss packet for non real time traffic when compared withHierarchical FIFO. In general, the performances of our approach draw near to Hierarchical EDF whichconfirms the effectiveness of this approac

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In recent years, collaborative environments play a significant role in collaboration work. The keys element of these environments is the process of collaboration. The calculation of the collaboration does not depend on the current collaboration but also on the past-time collaboration value. The value of collaboration is affected by time-invariant factors, as well as time. The time factor is a crucial element in determining the value of collaboration. This chapter discusses the effect of time on collaboration value, which influences the variation over time of the level of reliability of a collaborative environment. The proposal is based on the ability to measure the temporal variation of the reliability of a collaborative environment. Existing collaborative environments do not take this measurement time into account to determine the level of reliability of the collaboration. The simulations show that the approach offers more flexibility in interpreting the decay of collaboration over time.