Monte Carlo localization algorithm based on particle swarm optimization

In wireless sensor networks, Monte Carlo localization for mobile nodes has a large positioning error and slow convergence speed. To address the challenges of low sampling efficiency and particle impoverishment, a time sequence Monte Carlo localization algorithm based on particle swarm optimization (TSMCL-BPSO) is proposed in this paper. Firstly, the sampling region is constructed according to the overlap of the initial sampling region and the Monte Carlo sampling region. Then, particle swarm optimization (PSO) strategy is adopted to search the optimum position of the target node. The velocity of particle swarm is updated by adaptive step size and the particle impoverishment is improved by distributed estimation and particle replication, which avoids the local optimum caused by the premature convergence of particles. Experiment results indicate that the proposed algorithm improves the particle fitness, increases the particle searching efficiency, and meanwhile the lower positioning error can be obtained at the node\u27s maximum speed of 70 m/s

Silver decorated lanthanum calcium manganate for electrochemical supercapacitor

Perovskite La _0.5 Ca _0.5 MnO _3 (LCM) based materials are promising for electrode construction but their poor conductivities often lead to limited electrochemical performances. In this work, LCM was combined with Ag through the two-step process based on sol-gel and silver mirror reaction. The as-obtained LCM@Ag composites were characterized by scanning electron microscopy and x-ray powder diffraction. The mass percent determined by energy disperse spectroscopy combined with x-ray photoelectron spectroscopy was estimated at 5%. The electrochemical measurements showed LCM@Ag to possess superior specific capacitance of 287 C g ^−1 (179 F g ^−1 ) at 1.5 A g ^−1 while pure LCM delivered only 187 C g ^−1 (117 F g ^−1 ). The key to the improvement of performance can be attributed to the silver nanoparticle introduction, which leads to the enhancement of the electron transport capacity and ion diffusion for the composite. Meanwhile, the cycle stability slightly improved and the retention rate after 3,000 cycles at 10 A g ^−1 reached 66%. In sum, La _0.5 Ca _0.5 MnO _3 perovskite system looks promising for electrode construction, where silver modification could improve the overall electrochemical properties