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The next generation of cellular networks (Long Term Evolution) uses SC-FDMA (Single Carrier Frequency Division Multiple Access) on the uplink. In SC-FDMA, the uplink resources assigned to a user are called Resource Blocks (RBs) each of which consists of a set of consecutive subcarriers spanning all symbols available for data. Since at most one User Equipment (UE) is assigned to each RB then uplink...
The self-installation nature of femtocells sharing the same frequency band can lead to harmful femto-to-femto interference levels. The possibility for operators to share its licensed spectrum allows femtocells of one operator to exploit the frequency resources of other operators. In this paper we propose and analyze the performance of two dynamic frequency selection algorithms that permit to the generic...
In service-based systems (SBS), workflows are composed of loosely coupled services. The quality of service (QoS) of composite service-based workflows needs to be considered. In doing so, various aspects of the QoS of these workflows need to be assessed. In this paper, a user-centric approach is presented to assessing the confidentiality and integrity of service-based workflows, given the QoS of constituent...
Service composition is an important means for integrating the individual Web services for creating new value added systems that satisfy complex demands. Since, Web services exist in the heterogeneous environments on the Internet, study on how to guarantee the reliability of service composition in a distributed, dynamic and complex environment becomes more and more important. This paper proposes a...
QoS-aware service composition is to compose a composite service by selecting atomic services from service providers to maximize QoS while satisfying all the QoS constraints imposed by user requests. Many proposed schemes for service composition are atomic task oriented (ATO). Due to the possible large number of tasks contained in a composite service and the wide range of candidate services capable...
The transmission of stream media over the Internet require a high bandwidth. While the best-effort network could not provide constant transmission speed. The proxy server (PS) is the nearest part of the Internet to the client. The proxy can cache the data, and release the load of the servers. So the proxies have great influence on the video QoS. Through the perfect algorithm, within the acceptable...
In Service Oriented Architecture, Quality of Service (Qos) represents an important issue which is often considered when selecting and composing services. For receiving up-to-date information, non-functional properties can be continuously monitored using current methods. Because of the occurrence of monitoring at every time of service calling, the current methods imposes some overhead on the SOA. The...
Due to the dynamic nature of environment in service computing, it becomes more important to make the Web service composition able to self-adapt to changes in its environment. Achieving this goal is a challenging task, as the performance of a composite Web service will be decreased if the adaptation happens frequently in runtime. In this paper, we improve adaptation of Web service composition by predicting...
Personal Communication Services Systems provides global roaming and improved quality of services irrespective of the location of its users. One of the important and challenging issues in personal communication services systems is location management, which keeps track of the movement of the users. The existing user location strategies used for location management suffers from high signaling traffic...
Traffic Engineering (TE) broadly relates to optimization of the performance of a network. The Overlay approach has been widely used by many service providers for Traffic Engineering in large Internet backbones. In this approach logical connections are set up between edge nodes to form a full mesh virtual network on top of the physical topology. Instead of overlaying IP routing over the logical virtual...
When a stream application that demands real-time processing over continuous data streams is running on a network-on-chip (NoC)-based multiprocessor system-on-chip (MPSoC), two types of deadlocks may occur: (i) the routing-dependent deadlocks, and (ii) the message-dependent deadlocks. In this paper, we focus on the request-request type message-dependent deadlocks, the most devastating deadlocks in...
This paper presents the issue of capacity variable routing in Satellite-HAP system networks with multicasting capabilities, for different traffic types, with the objective of minimizing the short term traffic load oscillations and reacting to the long term changes of the traffic loads. This is realized by learning from the past and using it to influence the current decision. Some of the major QOS...
The massively growing demand for bandwidth-consuming real-time applications such as voice and video, added to the need of QoS being guaranteed are the main motivation of this work. In this paper we propose a new medium access mechanism that improves the performance of IEEE 802.11e EDCA wireless networks by minimizing the collision probability while maintaining high transmission probability. This was...
System capacity is an important factor that affects the performance of WiMAX system where the amount of data that can be delivered to the end user is determined based on the system capacity and users QoS requirements. This scenario is even more complex when multi-hop relays are introduced into the network whereas the user access capacity decreases with the increase of hop number. In order to maintain...
Network Calculus is a set of recent developments that provide deep performance analysis of communication networks. Central to the theory is the use of alternate algebras such as the min-plus algebra to transform complex network systems into analytically tractable systems. With network calculus, we are able to understand some fundamental properties of integrated services networks, window flow control,...
IEEE 802.15.4 defines the physical layer and medium access control sub-layer specifications for low-data-rate wireless connectivity devices with very limited battery consumption requirements typically operating in the personal operating space. Unlike traditional wireless networks, its unique characteristics, such as low-data-rate and guaranteed time slots (GTS), have brought unprecedented challenges...
Dynamic routing protocol involves the purchase order management among six participants which cooperate by multiple service interactions. Due to the complexities of interactions, it is important to check if the protocol will be stuck due to the fact that some required channels are not available (i.e. channel-absence) when an interaction is executed. Moreover, the quality of service (QoS) of the protocol...
In existing federated identity management systems it is more and more necessary new set of advanced policies, such as policies for the administrative delegation. They allow administrators to delegate a subset of the system policies management to other users, who will have a much wider knowledge in the application area where these policies will be applied. In this paper, we present an infrastructure...
Large-scale complex infrastructures are emerging as new computing platforms for the federation of world-wide mission critical systems over the Internet. However, standard approaches to data dissemination are still not adequate to the scale of these systems. The best-effort delivery guarantees of the Internet and the occurrence of node failures may compromise the correct and timely delivery of data,...
In Web Services composition, effectively appraising of QoS of Web Services is a main method of service selecting. Most of current QoS models do not consider the uncertainty, subjectivity, interacting and business relativity of the non-functional attributes of services. And they lack of the deep and thorough analysis of user requirements. Thus they are not able to provide sufficient support to service...
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