Deployment of Edge Computing Nodes in IoT:Effective Implementation of Simulated Annealing Method Based on User Location

Edge computing paradigm for 5G architecture has been considered as one of the most effective ways to realize low latency and highly reliable communication,which brings computing tasks and network resources to the edge of network.The deployment of edge computing nodes is a key factor affecting the service performance of edge computing systems.In this paper,we propose a method for deploying edge computing nodes based on user location.Through the combination of Simulation of Urban Mobility(SUMO)and Network Simulator-3(NS-3),a simulation platform is built to generate data of hotspot areas in Io T scenario.By effectively using the data generated by the communication between users in Io T scenario,the location area of the user terminal can be obtained.On this basis,the deployment problem is expressed as a mixed integer linear problem,which can be solved by Simulated Annealing(SA)method.The analysis of the results shows that,compared with the traditional method,the proposed method has faster convergence speed and better performance.

Progress and Challenges Toward Effective Flexible Perovskite Solar Cells

The demand for building-integrated photovoltaics and portable energy systems based on flexible photovoltaic technology such as perovskite embedded with exceptional flexibility and a superior power-to-mass ratio is enormous.The photoactive layer,i.e.,the perovskite thin film,as a critical component of flexible perovskite solar cells(F-PSCs),still faces long-term stability issues when deformation occurs due to encountering temperature changes that also affect intrinsic rigidity.This literature investigation summarizes the main factors responsible for the rapid destruction of F-PSCs.We focus on long-term mechanical stability of F-PSCs together with the recent research protocols for improving this performance.Furthermore,we specify the progress in F-PSCs concerning precise design strategies of the functional layer to enhance the flexural endurance of perovskite films,such as internal stress engineering,grain boundary modification,self-healing strategy,and crystallization regulation.The existing challenges of oxygen-moisture stability and advanced encapsulation technologies of F-PSCs are also discussed.As concluding remarks,we propose our viewpoints on the large-scale commercial application of F-PSCs.

Intelligent reflecting surface-assisted federated learning in multi-platoon collaborative networks

Inspired by mobile edge computing(MEC),edge learning has gained a momentum by directly performing model training at network edge without sending massive data to a centralized data center.However,the quality of model training will be affected by the limited communication and computing resources of network edge.In this paper,how to improve the training performance of a federated learning system aided by intelligent reflecting surface(IRS)over vehicle platooning networks is studied,where multiple platoons train a shared federated learning model.Multi-platoon cooperation can alleviate the pressure of data processing caused by the limited computing resources of single platoon.Meanwhile,IRS can enhance the inter-platoon communication in a cost-effective and energy-efficient manner.Firstly,the federated learning optimization problem of maximizing the learning accuracy is formulated by jointing platoon scheduling,bandwidth allocation and phase shifts at the IRS to maximize the number of scheduled platoon.Specif-ically,in the proposed learning architecture each platoon updates the learning model with its own data and uploads it to the global model through IRS-based wireless networks.Then,a method based on sequential optimization algorithm(SOA)and a group-based optimization method are analyzed for single IRS aided and large-scale IRS aided commu-nication,respectively.Finally,a platoon scheduling scheme is designed based on the communication reliability and computing reliability of platoons.Simulation results demonstrate that large-scale IRS assisted communication can effectively improve the reliability of multi-user communication networks.The scheduling scheme based on learning reliability balances the communication performance and computing performance of platoons.

Comparison of Extraction Methods for Total Alkaloids from Abrus Cantoniensis Hance

[Objectives] To compare different extraction methods for total alkaloids from Abrus Cantoniensis Hance taking chloroform as solvent. [Methods] The ethanol extraction method,ultrasonic extraction method,acid water extraction method,and Soxhlet extraction method were used to extract total alkaloids,and the total alkaloids of Abrus Cantoniensis Hance were measured at 238 nm wavelength. [Results] The extraction rate of ethanol extraction method was 14. 76 mg/100 g; the extraction rate of ultrasonic extraction method was 56. 85 mg/100 g; the extraction rate of acid water extraction method was 56. 63 mg/100 g; the extraction rate of Soxhlet extraction method was 58. 19 mg/100 g.[Conclusions]Results indicate that Soxhlet extraction method can obtain the highest extraction rate.