Ash Mohammad Abbas

Quality of Service in mobile ad hoc networks: a survey

To support multimedia applications, it is desirable that an ad hoc network has a provision of Quality of Service (QoS). However, the provision of QoS in a mobile ad hoc network is a challenging task. In this paper, we present a review of the current research related to the provision of QoS in an ad hoc environment. We examine issues and challenges involved in providing QoS in an ad hoc network. We discuss methods of QoS provisioning at different levels including those at the levels of routing, Medium Access Control (MAC), and cross layer. Also, we discuss schemes for admission control and scheduling that are proposed in the literature for the provision of QoS. We compare salient features of various solutions and approaches and point out directions for future work.

Weighted indices for evaluating the quality of research with multiple authorship

Devising an index to measure the quality of research is a challenging task. In this paper, we propose a set of indices to evaluate the quality of research produced by an author. Our indices utilize a policy that assigns the weights to multiple authors of a paper. We have considered two weight assignment policies: positionally weighted and equally weighted. We propose two classes of weighted indices: weighted h-indices and weighted citation h-cuts. Further, we compare our weighted h-indices with the original h-index for a selected set of authors. As opposed to h-index, our weighted h-indices take into account the weighted contributions of individual authors in multi-authored papers, and may serve as an improvement over h-index. The other class of weighted indices that we call weighted citation h-cuts take into account the number of citations that are in excess of those required to compute the index, and may serve as a supplement to h-index or its variants.

Bounds and Inequalities Relating h-Index, g-Index, e-Index and Generalized Impact Factor: An Improvement over Existing Models

In this paper, we describe some bounds and inequalities relating -index, -index, -index, and generalized impact factor. We derive the bounds and inequalities relating these indexing parameters from their basic definitions and without assuming any continuous model to be followed by any of them. We verify the theorems using citation data for five Price Medalists. We observe that the lower bound for -index given by Theorem 2, , comes out to be more accurate as compared to Schubert-Glanzel relation for a proportionality constant of , where is the number of citations and is the number of papers referenced. Also, the values of -index obtained using Theorem 2 outperform those obtained using Egghe-Liang-Rousseau power law model for the given citation data of Price Medalists. Further, we computed the values of upper bound on -index given by Theorem 3, , where denotes the value of -index. We observe that the upper bound on -index given by Theorem 3 is reasonably tight for the given citation record of Price Medalists.

An analytical framework for path reliabilities in mobile ad hoc networks

An ad hoc network is a collection of mobile nodes connected through multi-hop wireless links without the required intervention of any centralized access point or existing infrastructure. In this work, we have developed an analytical framework for computing the reliabilities of multi-hop paths. We have also investigated the effect of multi-path characteristics on path reliabilities. Among the main parameters considered here are, average link clustering, number of multiple paths, path complexity factor, and hop difference factor. Our approach is unified and general in the sense that it is able to incorporate single as well a multiple paths between a given source and destination pair.

Path Diminution is Unavoidable in Node-Disjoint Multipath Routing with Single Route Discovery

In an ad hoc network, identification of all node-disjoint paths between a given pair of nodes is a challenging task. The phenomena that a protocol is not able to identify all node-disjoint paths that exist between a given pair of nodes is called path diminution. In this paper, we discuss that path diminution is unavoidable when a protocol discovers multiple node-disjoint paths in a single route discovery. We discuss schemes to mitigate path diminution. However, no such scheme is guaranteed to discover all node-disjoint paths that exist between a given pair of nodes. We have proved that one cannot devise an efficient algorithm that is guaranteed to compute all node-disjoint paths between a given pair of nodes in a single route discovery

Path diminution in disjoint multipath routing for mobile ad hoc networks

An ad hoc network is a collection of mobile nodes connected through multi-hop wireless links without the required intervention of any centralized access point or existing infrastructure. Design of disjoint multipath routing protocols in an ad hoc environment is a challenging task. We have considered disjoint multipath routing schemes with path diminution in an ad hoc environment. Also, we have discussed the trade-off between the number of multiple paths searched and route establishment overheads.

Path diminution in node-disjoint multipath routing for mobile ad hoc networks is unavoidable with single route discovery

In an ad hoc network, identification of all node-disjoint paths between a given pair of nodes is a challenging task. The phenomena that a protocol is not able to identify all node-disjoint paths that exist between a given pair of nodes is called path diminution. In this paper, we discuss that path diminution is unavoidable when a protocol discovers multiple node-disjoint paths in a single route discovery. We discuss schemes to mitigate path diminution. However, no such scheme is guaranteed to discover all node-disjoint paths that exist between a given pair of nodes. We have proved that one cannot devise an efficient algorithm that is guaranteed to compute all node-disjoint paths between a given pair of nodes in a single route discovery.

An Analytical Framework for Route Failure Time of Multiple Node-Disjoint Paths in Mobile Ad hoc Networks

In a mobile ad hoc network, routes may often fail due to movements of nodes. In this paper, we analyze route failure time of multiple node-disjoint paths between a given pair of nodes. We discuss an exact expression for the expected value of route failure time when lifetimes of individual paths are independent and identically distributed random variables. In case lifetimes are not independent, we discuss an upper bound on route failure time. In order to validate the model, we simulate exponentially distributed random variables. Values of route failure time obtained from simulations are close to those obtained analytically

Topology control in heterogeneous mobile ad hoc networks

An ad hoc network is a cooperative engagement of a collection of mobile nodes without the required intervention of any centralized access point or existing infrastructure. Topology control is needed in ad hoc networks to conserve energy and maximize network lifetime while maintaining network connectivity. We propose a topology control protocol based on leader election and density based clustering. We also discuss the alone-soldier-node problem.

An Improvement over Incremental Approach for Guaranteed Identification of Multiple Node-Disjoint Paths in Mobile Ad hoc Networks

Identifying a maximal set of node-disjoint paths between a given source and a destination is a challenging task in mobile ad hoc networks. One cannot guarantee to identify the maximal set of node-disjoint paths in a single sequence of request-reply cycle. However, one can guarantee to identify the maximal set of node-disjoint paths in multiple attempts and in an incremental fashion. One may combine a protocol that tries to identify multiple node-disjoint paths in a single go with an incremental approach. In this paper, we present an improved version of an incremental protocol that is guaranteed to discover the maximal set of node-disjoint paths between a given source and a destination. We have analytically shown that our approach requires less number of route discoveries than that required by the existing incremental protocol. We have also discussed the scalability of the proposed approach.