Ring Signature-Based Conditional Privacy-Preserving Authentication in VANETs

Wireless Personal Communications - Vehicular ad hoc networks (VANETs) consist of vehicles with high mobility that broadcasts delay-intolerant safety and informative messages frequently. The real...     

An ultra wideband “OM” shaped DRA with a defected ground structure and dual polarization properties for 4G/5G wireless communications

This research article reports a new Dielectric Resonator Antenna (DRA) with its Dielectric resonator (DR) modified to an “OM” shape for UWB (3.1‐11.1 GHz), to support high data rate multimedia applications for 4G/5G communications. The proposed DRA reports a peak gain of 7.68 dB and a dual polarization behavior for a frequency band from 6 to 11.1 GHz. It has overall antenna dimensions of 50 × 40 × 4.87 mm³ and is fabricated on a commercially available Rogers RT 5880 substrate (with ε_r = 2.2), which is fed using a microstrip feedline with a P‐type transformer that offers an input impedance of 50 Ω to the DR. A conformal strip between the feedline and the OM shaped DR improves the impedance matching at the UWB frequency response of the DRA. This UWB frequency response is mainly because of its optimized “OM” shaped DR structure that excites a TE₁₁₁ mode at 4.9 GHz and two higher order modes TE₂₁₁ and TE₂₂₁ at resonant frequencies of 7.2 and 8.35 GHz, respectively. Additionally the proposed OM shaped DR also generates orthogonal modes of TE₂₁₁^x and TE₂₁₁^y at 6.5 and 7.2 GHz and TE₂₂₁^x and TE₂₂₁^y at 8.35 and 10 GHz, respectively. The proposed DRA therefore exhibits an elliptically polarized behavior with axial ratio bandwidth of 5.1 GHz (≤10 dB) from 6 to 11.1 GHz. A measured impedance bandwidth of 5.25 GHz from 3.8 to 9.05 GHz and 1.5 GHz from 10 to 11.5 GHz and a peak‐measured gain of 7.68 dB at 10.5 GHz (with an average gain of 4.6 dB) has been reported for the proposed DRA. An UWB performance, with good gain properties and an elliptically polarized behavior allows the proposed “OM” shaped DRA to be suitable for short range 4G/5G UWB wireless communications for future multimedia rich WPAN (wireless personal area networks), WLAN, Wi‐MAX, INSAT applications, satellite applications, and X band RADAR (for defense communication) applications.     

Performance Study of Dual Unmanned Aerial Vehicles with Underlaid Device-to-Device Communications

Wireless Personal Communications - Unmanned aerial vehicle (UAV) as an aerial base station is a predominant cost-effective solution of coverage extension in wireless communication network. It has a...     

Approximate controllability of stochastic delay differential systems driven by Poisson jumps with instantaneous and noninstantaneous impulses

Control systems in which instantaneous and noninstantaneous impulses occur simultaneously are difficult to handle. In this article, we investigate the solvability and approximate controllability for a new category of stochastic differential equations steered by Poisson jumps with instantaneous and noninstantaneous impulses. Utilizing the theory of fundamental solution, stochastic analysis, the measure of noncompactness, and the fixed-point approach, we establish the presence of a mild solution for the proposed system. We have also constructed a new set of sufficient constraints that assures approximate controllability of the considered system. Next, we discuss the existence of a solution and approximate controllability for an impulsive deterministic control system in which the nonlinear term contains spatial derivatives. Lastly, two examples are presented to encapsulate the abstract results.     

Design and reliability analysis of fault-tolerant shuffle exchange gamma logical neighborhood interconnection network

The Journal of Supercomputing - Multistage interconnection networks are used as a medium for interconnecting processors and memories in multiprocessor systems. Multistage interconnection networks...     

Secure data hiding scheme using shape generation algorithm: a key based approach

Data hiding in images has evolved as one of the trusted methods of secure data communication and numerous approaches have been introduced over the years using gray scale images as the cover media. Most of the methods are based on data hiding in least significant bit planes of cover images. Many such methods purely depend on data substitution algorithms by defining a pattern in which data is embedded. One can gain access to the secret data in a few attempts, if the algorithm is known. Keeping this in view several approaches based on secret keys have also been proposed by researchers. This paper proposes an efficient data embedding scheme using a key and an embedding pattern generated through midpoint circle generation algorithm. The pattern can be applied to a carrier that is mapped onto a grid/image. The cryptosystem uses the concept of steganography and is computationally light and secure. The secret-key is generated in such a way that Avalanche effect is ensured except in very rare cases. The proposed data embedding method is shown to be robust and highly secure while maintaining good hiding capacity and imperceptibility. It is applicable for data hiding in a generic grid that could be of pixels or bits.     

A fuzzy decision scheme for relay selection in cooperative wireless sensor network

In energy‐constrained military wireless sensor networks, minimizing the bit error rate (BER) with little compromise on network lifetime is one of the most challenging issues. This paper presents a new relay selection based on fuzzy logic (RSFL) scheme which provides balance between these parameters. The proposed scheme considers node's residual energy and path loss of the relay‐destination link as the input parameters for the selection of the relay node. The relay node selection by fuzzy logic is based on prioritizing higher residual energy and minimum path loss. To evaluate the performance on wireless sensor network, we compare the proposed scheme with the three existing relay selection strategies, ie, random, maximum residual energy based relay selection (MaxRes), and minimum energy consumption based relay selection (MinEnCon). The simulation results of the proposed scheme in terms of network lifetime, BER, Network Survivability Index (NSI), and average energy of network nodes have been presented and compared with different relay selection schemes. The simulation results show that the proposed RSFL scheme has the lowest BER, moderate network lifetime, average energy, and NSI.     

Filament Nucleation Tunes Mechanical Memory in Active Polymer Networks

Incorporating growth into contemporary material functionality presents a grand challenge in materials design. The F‐actin cytoskeleton is an active polymer network that serves as the mechanical scaffolding for eukaryotic cells, growing and remodeling in order to determine changes in cell shape. Nucleated from the membrane, filaments polymerize and grow into a dense network whose dynamics of assembly and disassembly, or “turnover,” coordinates both fluidity and rigidity. Here, the extent of F‐actin nucleation is varied from a membrane surface in a biomimetic model of the cytoskeleton constructed from purified protein. It is found that nucleation of F‐actin mediates the accumulation and dissipation of polymerization‐induced F‐actin bending energy. At high and low nucleation, bending energies are low and easily relaxed yielding an isotropic material. However, at an intermediate critical nucleation, stresses are not relaxed by turnover and the internal energy accumulates 100‐fold. In this case, high filament curvatures template further assembly of F‐actin, driving the formation and stabilization of vortex‐like topological defects. Thus, nucleation coordinates mechanical and chemical timescales to encode shape memory into active materials.     

Room-Temperature Gas Sensing Properties of Nanocrystalline-Structured Indium-Substituted Copper Ferrite Thin Film

Nanocrystalline indium-substituted copper ferrite thin film has been prepared by a chemical coprecipitation method and characterized by x-ray diffraction (XRD) analysis, scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier-transform infrared (FTIR) spectroscopy, ultraviolet–visible (UV–Vis) spectroscopy, and gas sensing measurements. XRD and SEM analyses revealed heterogeneous particle formation with cubic structure. Fourier-transform infrared (FTIR) spectroscopy revealed normal behavior for ferrite materials. The bandgap of the material was found to lie in the range of 1.54 eV, implying semiconducting nature. Gas sensor analysis revealed excellent sensing behavior at room temperature. The material showed fast detection response for liquefied petroleum gas (LPG) at low concentration, with enhanced sensitivity at increased LPG concentration. The thin-film sensor showed repeatability nature with reproducibility of ～ 96%.