Nework topology for maximizing the terminal reliability in a Computer Communication Network

In the design of a Computer Communication Network (CCN), the reliability between any pair of nodes and the maximum permissible installation cost are of great importance. These characteristics are largely dependant upon the topological layout of the links, their costs and reliabilities. Having the knowledge of the topological layout of the various computer centres (nodes) and maximum permissible cost of installing the various links at their pre-assigned positions; in this paper an algorithm for obtaining an optimal network topology which gives the maximum s?t reliability is presented. The developed method is general and is computerized. The proposed method has an additional advantage that the system is not to be redesigned, if at a later stage the permissible cost is enhanced by budgetary provisions. An example illustrates the algorithm.     

Adaptive MAC Protocol for Solar Energy Harvesting Based Wireless Sensor Networks in Agriculture

The wireless sensor network is one of the promising technologies in the agriculture field. Its actual usage in real agriculture fields is limited by its dependence on the small batteries which cannot make the network survive for long. Various protocols are being designed at the network and MAC layer to increase the lifetime of the nodes, but up to a certain extent only. Hence the energy harvesting to power up the WSN nodes is a promising technology to fulfill this ever energy demand, but the protocols need to be redesigned for this scenario. Solar energy harvesting based MAC protocol which is adaptive to the changing weather conditions is designed in this paper for the smart agriculture applications. It is based on the multilayer and receiver-initiated process to improve network quality. It has shown the remarkable performance over the other energy harvesting based protocols in terms of ENO ratio, energy consumption and collision rate.

     

A stable energy efficient clustering protocol for wireless sensor networks

Sensor networks comprise of sensor nodes with limited battery power that are deployed at different geographical locations to monitor physical events. Information gathering is a typical but an important operation in many applications of wireless sensor networks (WSNs). It is necessary to operate the sensor network for longer period of time in an energy efficient manner for gathering information. One of the popular WSN protocol, named low energy adaptive clustering hierarchy (LEACH) and its variants, aim to prolong the network lifetime using energy efficient clustering approach. These protocols increase the network lifetime at the expense of reduced stability period (the time span before the first node dies). The reduction in stability period is because of the high energy variance of nodes. Stability period is an essential aspect to preserve coverage properties of the network. Higher is the stability period, more reliable is the network. Higher energy variance of nodes leads to load unbalancing among nodes and therefore lowers the stability period. Hence, it is perpetually attractive to design clustering algorithms that provides higher stability, lower energy variance and are energy efficient. In this paper to overcome the shortcomings of existing clustering protocols, a protocol named stable energy efficient clustering protocol is proposed. It balances the load among nodes using energy-aware heuristics and hence ensures higher stability period. The results demonstrate that the proposed protocol significantly outperforms LEACH and its variants in terms of energy variance and stability period.     

An Adaptive Weighted Min-Mid-Max Value Based Filter for Eliminating High Density Impulsive Noise

In this study, non-orthogonal multiple access (NOMA) together with cognitive radio (CR) benefit to the vehicle-to-everything (V2X) as promising application with high spectrum efficiency. We have higher priority to evaluate system performance of the secondary network in such CR-NOMA system operating in the context of V2X. We first arrange vehicles belonging to serving group in this CR-NOMA assisted V2X, and it is beneficial to serve massive connections for vehicles. There are two scenarios studied in this paper, with and without the support of CR scheme. In our proposed system, two system metrics need be investigated to evaluate performance of vehicles that need higher quality of service (QoS). Our results indicate that the outage performance gap among two vehicles exists since different transmit power allocation factors were assigned to them. In particular, the outage probability is first derived in exact forms and then the bit error rate (BER) can be further achieved. In specific situations, the optimal outage probability can be obtained by numerical simulations. Simulation results are also provided to verify the correctness of the derived expressions and it exhibits advantages of the proposed CR-NOMA assisted V2X system in terms of two main metrics such as outage probability and BER.

     

Recent Advances in MAC Protocols for the Energy Harvesting Based WSN: A Comprehensive Review

Wireless Personal Communications - Wireless sensor networks are catching the attention of the researchers in various fields like structural, healthcare monitoring, but the real world adoption is...     

Curcumin loaded PEG400‐OA nanoparticles: A suitable system to increase apoptosis,decrease migration,and deregulate miR‐125b/miR182 in MDA‐MB‐231 human breast cancer cells

Curcumin is an anti‐cancerous agent, but its low‐solubility limits its clinical use. The relationship between deregulation of miRNAs and their targets suggested that miRNAs can be interest targets of curcumin in treatment of different cancers. In this study, to overcome essential defects of the clinical usage of this golden drug, curcumin‐encapsulated polymersome nanoparticles (CPNs) have been developed, and the cytotoxicity effects were studied on MDA‐MB‐231 breast cancer cells. The expression level of miR‐182/125b and the expression pattern of some potential targets in apoptotic pathway, predicted by in silico approaches, were analyzed by RT‐qPCR in CPNs‐treated and untreated cells. Moreover, the amount of CASP9 and CASP8 proteins were determined by Western blotting. The effect of CPNs on cell migration were studied by scratch test and the level of EGFR, E‐cadherin, and beta‐catenin proteins were monitored in CPNs‐treated and untreated cells by western blotting. RT‐qPCR analysis identified the downregulation of miR‐125b and miR‐182 in CPNs‐treated cells and the upregulation of some predicted apoptotic target genes such as P53, CASP9 and BAX after 24 hours. Western blotting confirmed the effects of curcumin on the increase of cleaved CASP9 protein. Based on data from the current experiment, the migration of MDA‐MB‐231 cells was decreased after CPNs treatment. According to the results, CPNs, as suitable and compatible nanocarriers, can deliver curcumin into cancerous cells more effectively and can increase the therapeutic effects of curcumin on MDA‐MB‐231 cells partly by suppression of miR‐125b and miR‐182 as well as induction of apoptosis and inhibition of metastatic progression.     

BER performance of MQAM with L‐branch MRC diversity reception over correlated Nakagami‐m fading channels

Exact and closed form generalized expressions for bit error rate (BER) of M‐ary quadrature amplitude modulation (MQAM) with L‐branch maximal ratio combining (MRC) space diversity reception in fading channels are derived and analyzed. The fading channels are modeled as identical but correlated frequency‐nonselective slow Nakagami‐m fading channels corrupted by additive white Gaussian noise (AWGN). Analytical results obtained are in terms of few finite range integrals with an integrand composed of elementary functions. Because of their simple form, these analytical results readily allow numerical evaluation in cases of practical interest. The results are also general enough to include Nakagami‐m fading channels with and without correlation, no diversity system, Rayleigh fading channels with and without correlation, and AWGN as special cases. The numerical results for the case of 16QAM are shown graphically and also in tabular form in order to examine the effects of fading severity, order of diversity, and branch correlation on the BER performance. The two correlation models considered are constant correlation model and exponential correlation model. One may be interested to know how the BER of MQAM is related to symbol error rate (SER) of MQAM. Therefore, the BER results obtained in this paper are also compared with that obtained directly from the SER. It is expected that the analytical results presented in this paper will provide a convenient tool for design and analysis of a radio communication system with space diversity reception in uncorrelated and correlated fading environment. Copyright © 2002 John Wiley & Sons, Ltd.     

Evolution of PAPR Reduction Techniques: A Wavelet Based OFDM Approach

Wireless Personal Communications - Orthogonal frequency division multiplexing (OFDM) is considered among the most suitable multiplexing technique for realizing high speed wireless communication in...     

Flower pollination algorithm‐based energy‐efficient stable clustering approach for WSNs

The advances in the size, cost of deployment, and user‐friendly interface of wireless sensor devices have given rise to many wireless sensor network (WSN) applications. WSNs need to use protocols for transmitting data samples from event regions to sink through minimum cost links. Clustering is a commonly used method of data aggregation in which nodes are organized into groups to reduce energy consumption. Nonetheless, cluster head (CH) has to bear an additional load in clustering protocols to organize different activities within the cluster. Proper CH selection and load balancing using efficient routing protocol is therefore a critical aspect for WSN's long‐term operation. In this paper, a threshold‐sensitive energy‐efficient cluster‐based routing protocol based on flower pollination algorithm (FPA) is proposed to extend the network's stability period. Using FPA, multihop communication between CHs and base station is used to achieve optimal link costs for load balancing distant CHs and energy minimization. Analysis and simulation results show that the proposed algorithm significantly outperforms competitive clustering algorithms in terms of energy consumption, stability period, and system lifetime.