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S. Rehman

Publications and source records attributed to S. Rehman.

3 recordsLinked to original sources

Dynamics of self-gravitating systems in non-linearly magnetized chameleonic Brans-Dicke gravity

We study the effects of magnetic fields of non-linear electrodynamics in chameleonic Brans-Dicke theory under the existence of anisotropic spherical fluid. In particular, we explore dissipative and non-dissipative self-gravitating systems in the quasi-homologous regime with the minimal complexity constraint. As a result, under the aforementioned circumstances, several analytic solutions are found. Furthermore, by analyzing the dynamics of a dissipative fluid, it is demonstrated that a void covering the center can satisfy the Darmois criteria. The temperature of the self gravitating systems is also investigated.

gr-qc

Analyzing Energy-efficiency and Route-selection of Multi-level Hierarchal Routing Protocols in WSNs

The advent and development in the field of Wireless Sensor Networks (WSNs) in recent years has seen the growth of extremely small and low-cost sensors that possess sensing, signal processing and wireless communication capabilities. These sensors can be expended at a much lower cost and are capable of detecting conditions such as temperature, sound, security or any other system. A good protocol design should be able to scale well both in energy heterogeneous and homogeneous environment, meet the demands of different application scenarios and guarantee reliability. On this basis, we have compared six different protocols of different scenarios which are presenting their own schemes of energy minimizing, clustering and route selection in order to have more effective communication. This research is motivated to have an insight that which of the under consideration protocols suit well in which application and can be a guide-line for the design of a more robust and efficient protocol. MATLAB simulations are performed to analyze and compare the performance of LEACH, multi-level hierarchal LEACH and multihop LEACH.

cs.NI

Optimal Number of Cluster Head Selection for Efficient Distribution of Sources in WSNs

In this paper, we compare problems of cluster formation and cluster-head selection between different protocols for data aggregation and transmission. We focus on two aspects of the problem: (i) how to guess number of clusters required to proficiently consume available sources for a sensor network, and (ii) how to select number of cluster-heads to cover up sensor networks more proficiently. A sensor in Wireless Sensor Networks (WSNs) can communicate directly only with other sensors that are within a radio range in a cluster. However, in order to enable communication between sensors not within communication range, they must form new clusters in distributed sensors. Several clustering algorithms such as LEACH, DEEC, and SEP have been proposed with the objectives of energy minimization, route-path selection, increased connectivity and network longevity. LEACH protocol and the similar ones assume an energy homogeneous system where a node is not likely to fail due to failure in connectivity and packet dropping. More recent protocols like SEP and TEEN considered the reverse that is energy heterogeneity which is more applicable to case of WSNs. We developed a bi-dimensional chain model to select average number of for DEEC. Simulation results are used to compare performance of different protocols to found optimal solutions of above mentioned problems.

cs.NI