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Data grids support distributed data-intensive applications that need to access massive datasets stored around the world. Ensuring efficient access to such datasets is hindered by the high latencies of wide-area networks. To speed up access, files can be replicated so a user can access a nearby replica. Much of the work on the replica placement problem in data grids has focused on average system performance...
Computing constrained shortest paths is fundamental to some important network functions such as QoS routing and traffic engineering. This paper introduces a polynomial time approximation Quality of Service (QoS) routing algorithm and constructs dynamic state-dependent routing policies. The proposed algorithm uses a bio-inspired approach based on the trial/error paradigm combined with swarm adaptive...
This paper presents a novel shared mesh restoration scheme for survivable multilayered networks with Shared Risk Link Groups (SRLG) considerations. We develop a heuristic restoration scheme called Two-Step Partial Protection Risk Algorithm to tackle three major problems: (1) network survivability (2) optimization of spare bandwidth, and (3) offering differentiated classes of service. The proposed...
Many applications in the Internet today demand high end-to-end Quality of Service (QoS) assurance, such as bandwidth, delay, jitter and packet loss constraints. Also they seek better utilization of the network resources, while satisfying customer needs. Multi-constrained optimal path (MCOP) QoS routing problem attempts to find a feasible path that satisfies the requested QoS constraints, while maintaining...
In this paper we validate through simulations the convergence properties of our earlier proposed balls and bins channel allocation algorithm. The algorithm supports dynamic channel allocation based on local link quality information and does not require exchange of network information. Each radio evaluates periodically a cost function related to the desired QoS. Based on the calculated cost the radio...
Tree-based backbone establishment and maintenance in mobile ad hoc - delay tolerant networks is often operated through the use of traversing tokens. A study and framework are proposed here for various token traversal strategies on tree-based backbones. The proposed strategies execute in a distributed and purely decentralized manner, and require only 1-hop knowledge. Aiming at providing the highest...
In this paper, we propose a power control algorithm using game theory for cognitive radio networks. A novel framework is presented to meet different SIR constrains which can guarantee the cognitive radio user's QoS requirement. We define a cost function which can effectively control the network power consumption. With the given cost function, the second user can achieve a better performance related...
In this paper we verify and study through implementation our earlier game theory algorithm for load balanced dynamic channel assignment. In our algorithm every cognitive radio is initially assigned a channel in a random fashion. The radios periodically evaluate a cost function related to a Quality of Service (QoS) parameter and may change the transmission channel with probability proportional to the...
Quality of service (QoS) is an important issue in delay tolerant mobile ad-hoc networks (DTMs). This work attempts to improve the QoS in DTMs by relying on spanning forests algorithms. The existing algorithms are improved by introducing the notion of trust and choosing the most robust (trustable) spanning trees among existing opportunities. The robustness/quality of the tree can be assessed based...
This paper investigates effects of pilot assisted channel estimation on dynamic resource allocation in a multiuser orthogonal frequency division multiplexing (OFDM) system. The channel estimation is done in each OFDM symbol through least-squared error (LSE) or minimum mean-squared error (MMSE) algorithm. The performance of each of these algorithms is evaluated through computer simulations. The maximal...
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