Abstract We propose a new modification to the A* algorithm named AA* that significantly improves space and time complexities. In AA*’s forward pass, the node sets (open and closed) are not used, and only the local node neighborhood is saved to take the next move decision. AA* needs a backward pass to bridge and correct gaps and bad decisions made in the forward pass. The work of the backward pass is far less than that of the forward pass, as most of the task has been done. It is shown via empirical experimental work that our proposed AA* algorithm is superior to the classical A* algorithm in the typical three metrics: running time, number of probed nodes, and length of path. Furthermore, our experimental work showed that AA* is suboptimal in terms of length of path compared to the original Dijkstra’s algorithm with an accuracy of 96.95%.

Abstract The beamforming approach has been emerging as a very important concept for next generation networks. In addition to the improved channel capacity, spectral efficiency, energy efficiency, secrecy rate and secrecy outage probability, the upcoming fifth generation network mainly aims at enhancing the parameters of the channel for secure communication. In this paper, we have implied the allocation of resource blocks adaptively using HMM with a beamforming approach in an intruded network. A system model for secure communication in an intruded network has been discussed using a beamforming approach with the main motive being to provide a security scenario to the data which is transmitted over an unsecured channel in a network. In addition to this we have used the approach of HMM for allocating the resource blocks to the users which have been demanded and applied in order to avoid the intrusion and wastage of resource blocks.

Abstract Recently, significant research has been conducted on magnetic metamaterials that exhibit negative permeability and operate within the GHz and MHz frequency ranges. These metamaterial structures can be utilized to improve the efficiency of near-field wireless power transfer systems, subterranean communication, and position sensors. However, in most cases, they are only designed to work for a single application. This study focuses on examining the transmission of magneto-inductive waves in magnetic metamaterial structures with ordered arrangements. This structure can be used simultaneously for wireless power transfer and near-field communications. The unit cell is formed by a spiral with five turns that is implanted on a FR-4 substrate. An external capacitor was used to regulate the resonant frequency of the magnetic metamaterial unit cell. The properties of magneto-inductive waves, including reflection, transmission response, and field distribution on the waveguide, have been extensively computed and simulated. The obtained results indicate that both 1-dimensional and 2-dimensional magnetic metamaterial configurations possess the ability to conduct electromagnetic waves and propagate magnetic field energy at a frequency of 13.56 MHz. The straight and cross path configurations were also investigated to identify the optimal configuration on the 2-dimensional metamaterial slab.