A secure multi-hop relay node selection scheme based data transmission in wireless ad-hoc network via block chain

In today’s scenario, data transmission is established through the single or multi-hop relay nodes in Wireless Ad-Hoc Networks (WANET). Traditional relay node selection techniques undergo collusion attacks, increased energy consumption, delay, and reduced network lifetime. To cope with these problems, we propose a Quantum Atom Search Optimization coupled with Blockchain aided Data Transmission (QASO-BDT) scheme for a relay node selection with security aided data transmission. This approach comprises three phases such as registration, clustering, and transmission. Initially, in the node registration phase every sensor node gets registered in the blockchain network through Capillary Gateway (CG). Next, in the clustering phase, a CH is selected and an enhanced multi-view clustering model is used to cluster the nodes into several clusters. Finally, the multi-hop transmission phase assists in best relay node selection for multi-hop transmission using QASO, and the blockchain-based transaction is carried out to ensure security in the system. The proposed scheme is simulated in the MATLAB platform and achieves a result of 91.5% throughput, the reduced energy value of 40%, end to end delay of 20.6%, and the exhaustion of node is 1% which results in an increased lifetime of the nodes. Also, security is evaluated in comparison with other traditional methods.

     

A two-stage filter for high density salt and pepper denoising

Image restoration is an important and interesting problem in the field of image processing because it improves the quality of input images, which facilitates postprocessing tasks. The salt-and-pepper noise has a simpler structure than other noises, such as Gaussian and Poisson noises, but is a very common type of noise caused by many electronic devices. In this article, we propose a two-stage filter to remove high-density salt-and-pepper noise on images. The range of application of the proposed denoising method goes from low-density to high-density corrupted images. In the experiments, we assessed the image quality after denoising using the peak signal-to-noise ratio and structural similarity metric. We also compared our method against other similar state-of-the-art denoising methods to prove its effectiveness for salt and pepper noise removal. From the findings, one can conclude that the proposed method can successfully remove super-high-density noise with noise level above 90%.

     

Himalayan waters at the crossroads: issues and challenges

The Hindu Kush Himalayas are called the water towers of Asia as they are the source of 10 major rivers and have the largest snow and ice deposits outside the two poles. Water emanating from the HKH provides food, energy and ecosystem services to up to 1.3 billion people. Climate change and socio-economic and demographic changes have put unprecedented pressure on these water resources, leading to uncertain supplies, increased demands and higher risks of extreme events like floods and droughts. The eight articles in this special issue highlight various dimensions of the Himalayan water resources by focusing on both physical and social science aspects of water management.     

Image denoising by anisotropic diffusion with inter-scale information fusion

Anisotropic partial differential equations (PDEs) based schemes for denoising digital images are fast becoming an indispensable tool in computer vision problems. In this paper we propose to denoise noisy images via such multiscale anisotropic diffusion. In general, digital images contain objects of multiple scales and denoising them without destroying edges is one of the main objective in early computer vision problems. Unlike the previous approaches, which discard the multiple scale based images produced by anisotropic PDE, we utilize information contained in them. By effectively combining the inter-scale details, the proposed scheme improves upon the noise removal and detail preservation properties over other schemes. Numerical results indicate that the scheme achieves good denoising with edge preservation on a variety of images.     

Acid‐catalyzed isobutane–isobutylene alkylation in liquid carbon dioxide solution

Liquid carbon dioxide was studied as a solvent for the isobutane–isobutylene alkylation. The acid catalysts in the reaction were anhydrous HF (AHF), pyridinium–poly(hydrogen fluoride) complex (PPHF), concentrated sulfuric acid and trifluoromethanesulfonic acid (TFSA). The effect of the acid–hydrocarbon volume ratio, temperature and residence time on the alkylate quality were studied over the temperature range of 50 T 0 °C. Carbon dioxide as a competing weak base decreases the acidity of the system which parallels the alkylate quality. In the case of HF and TFSA catalysts, solvent CO₂ increased the octane number of the alkylate product (RON 95.6 for HF and 88.0 for TFSAcatalyzed alkylation with CO₂ solvent).     

Functionalization of poly(4‐vinyl pyridine) grafted cellulose by quaternization reactions and a study on the properties of postquaternized copolymers

Graft copolymers of 4‐vinyl pyridine (4‐VP) synthesized by using simultaneous gamma irradiation method were further functionalized by post polymer quaternization reactions at N: of the pyridine ring of the graft copolymers. Using the optimum grafting conditions reported earlier for the grafting of 4‐VP onto extracted cellulose, graft copolymer was synthesized in bulk and was further functionalized by quaternization with hexyl bromide (C₆H₁₃Br), benzyl chloride (C₆H₅CH₂Cl), n‐butyl bromide (C₄H₉Br), and maleic anhydride (MAnh). The quaternized polymers were studied for treatment of hardness of water, antibacterial action, emulsification properties, metal ion uptake and stability toward thermal degradation, and enzymatic and alkaline hydrolysis to evaluate the suitability of these polymers in harsh chemical, microbial, and thermal environments. The functionalized polymers were also characterized for surface morphology (SEM), elemental analysis and FTIR for investigations of structural aspects, and to obtain evidence for quaternization. The functionalized copolymers exhibit a range of properties that can be used in many fields of water purification technologies including antibacterial agents and ion exchangers. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 2454–2464, 2004     

Nafion-H catalyzed condensation of acetophenone derivatives. A preparative route of 1,3,5-Triarylbenzenes [1]

Nafion-H, a perfluorinated resinsulfonic acid, catalyzes condensation of acetophenones to provide 1,3,5-triarylbenzenes under relatively mild conditions. Reaction are clean, and water formed as by-product does not deactivate the catalyst. However, ortho-substituted     

Improving the usability of standard schemas

Due to the development of XML and other data models such as OWL and RDF, sharing data is an increasingly common task since these data models allow simple syntactic translation of data between applications. However, in order for data to be shared semantically, there must be a way to ensure that concepts are the same. One approach is to employ commonly usedschemas—called standard schemas —which help guarantee that syntactically identical objects have semantically similar meanings. As a result of the spread of data sharing, there has been widespread adoption of standard schemas in a broad range of disciplines and for a wide variety of applications within a very short period of time. However, standard schemas are still in their infancy and have not yet matured or been thoroughly evaluated. It is imperative that the data management research community takes a closer look at how well these standard schemas have fared in real-world applications to identify not only their advantages, but also the operational challenges that real users face.     

NB+: An improved Naïve Bayesian algorithm

A novel algorithm named NB⁺ which is an extended version of the traditional Naïve Bayesian algorithm has been presented in this paper. An exception occurs when there is an equal probability for the class label value in the Naïve Bayesian algorithm. The approach aims to suggest a solution with the help of a partial matching method. Consequently, the classification accuracy has drastically improved. Experimental evaluation has been done on various databases to show that NB⁺ algorithm outperforms the traditional Naïve Bayesian algorithm.