Modified Black Widow Optimization-Based Enhanced Threshold Energy Detection Technique for Spectrum Sensing in Cognitive Radio Networks

This study develops an Enhanced Threshold Based Energy Detection approach(ETBED)for spectrum sensing in a cognitive radio network.The threshold identification method is implemented in the received signal at the secondary user based on the square law.The proposed method is implemented with the signal transmission of multiple outputs-orthogonal frequency division multiplexing.Additionally,the proposed method is considered the dynamic detection threshold adjustments and energy identification spectrum sensing technique in cognitive radio systems.In the dynamic threshold,the signal ratio-based threshold is fixed.The threshold is computed by considering the Modified Black Widow Optimization Algorithm(MBWO).So,the proposed methodology is a combination of dynamic threshold detection and MBWO.The general threshold-based detection technique has different limitations such as the inability optimal signal threshold for determining the presence of the primary user signal.These limitations undermine the sensing accuracy of the energy identification technique.Hence,the ETBED technique is developed to enhance the energy efficiency of cognitive radio networks.The projected approach is executed and analyzed with performance and comparison analysis.The proposed method is contrasted with the conventional techniques of theWhale Optimization Algorithm(WOA)and GreyWolf Optimization(GWO).It indicated superior results,achieving a high average throughput of 2.2 Mbps and an energy efficiency of 3.8,outperforming conventional techniques.

Design and analysis of multi-channel drop filter using dual L defected hexagonal photonic crystal ring resonator

In this paper,dual L defected hexagonal Photonic Crystal Ring Resonator(PCRR)using Channel Drop Filter(CDF)is designed for Coarse Wavelength Division Multiplexing(CWDM)systems.In this structure,the external rods of the ring resonator are arranged in a hexagon and the internal rods are removed in L arrangement for introducing defects.Scatter rods are used to prevent leakage.By using the L defected hexagonal resonator,a multi-channel CDF is designed,which exhibits multiple wavelengths of CWDM(1500 nm–1600 nm)region.In addition,the selection of rod size and the position of rods in the proposed multi-channel CDF are validated by varying the radius of coupling and scattering rods,as well as the position of resonators,respectively.By using plane wave expansion and opti Finite Difference Time Domain(FDTD)method,the electromagnetic wave propagation and the photonic band gap are obtained.

肿瘤病人在进行多层CT随访时无需常规使用口服阳性对比剂

该回顾性医学分析的目的是评价肿瘤病人进行多层CT随访时停止常规使用口服对比剂对阅片满意度的影响。分析100例病人CT检查经历表明，口服阳性对比剂是他们最不愉快的经历（P〈0．0001）。对447例一般肿瘤病人进行多层CT随访检查时放弃常规口服阳性对比剂，以2．5mm进行多层重组，随访5～13个月。

Spin-Relaxation of NiO Encapsulated Gd_2O_3 Core–Shell Nanoparticles

Nickel oxide encapsulated gadolinium oxide(Gd2O3/NiO) core–shell nanoparticles(Nps) has been synthesized by polyol method and analyzed by transmission electron microscopy.The particle size is found to vary from 25 to 35 nm.Raman spectra show the gadolinium oxide core material peaks are found to be diminished by the mass effect of the NiO shell material.The dynamics of the magnetic moment has been studied with the help of temperature dependent electron paramagnetic resonance(EPR) spectroscopy.Peak-to-peak line width(DHpp) value of the EPR spectra increases with decreasing temperature.Temperature dependence of line width shows the dominance of spin–lattice relaxation in these systems,and it can be used as T1contrast agent.Spin number estimated from EPR studies increases with the decrease of the temperature.The interfacial exchange coupling between the core and shell region is found to be existing at very low temperatures as determined by EPR studies in this non-magnetic/antiferromagnetic(NM/AFM) core/shell nanosystem.The effects of the temperature on the magnetic properties of the Gd2O3/NiO core/shell NPs and the underlying mechanism have been discussed.