Federated Learning with Blockchain for Privacy-Preserving Data Sharing in Internet of Vehicles

Data sharing technology in Internet of Vehicles(Io V)has attracted great research interest with the goal of realizing intelligent transportation and traffic management.Meanwhile,the main concerns have been raised about the security and privacy of vehicle data.The mobility and real-time characteristics of vehicle data make data sharing more difficult in Io V.The emergence of blockchain and federated learning brings new directions.In this paper,a data-sharing model that combines blockchain and federated learning is proposed to solve the security and privacy problems of data sharing in Io V.First,we use federated learning to share data instead of exposing actual data and propose an adaptive differential privacy scheme to further balance the privacy and availability of data.Then,we integrate the verification scheme into the consensus process,so that the consensus computation can filter out low-quality models.Experimental data shows that our data-sharing model can better balance the relationship between data availability and privacy,and also has enhanced security.

Bacterial communities and volatile organic compounds in traditional fermented salt-free bamboo shoots

Fermented bamboo shoot is a traditional salt-free fermented vegetable product,which has been widely used as cooking ingredient in southern China.This paper intends to evaluate the changes of bacterial diversity and volatile organic compounds(VOCs)in bamboo shoots during fermentation.FT-IR spectra confirmed the significant original difference in transmittance between fresh and fermented bamboo shoots.Four VOCs in fresh bamboo shoots,namelyα-gurjunene,p-cresol,methoxyphenyloxime,hexanal,were retained after fermentation.At the same time,new VOCs,namelyβ-cedrene,ethyl caprylate,1-nonanal,4-methylanisole,(z)-2-heptenal,acetic acid,valeraldehyde,1-hexanol,ethyl palmitate were produced.Among them,the concentration of p-cresol was the highest among all VOCs.At the phylum level,proteobacteria was the dominant bacterial biota in fresh bamboo shoots(GC-0 group).Firmicutes became the dominant bacterial biota in fermented samples.At the genus level,bacterial groups in fresh bamboo shoots were dominated by Oxyphotobacteria(unclassified)and Lactobacillus.With the progress of fermentation,Lactobacillus increased continuously and finally became the dominant bacterial biota.Weissella appeared in the early stage of fermentation,but began to decline to less than 0.1%in the later stage.Lactobacillus became increasingly abundant during fermentation,and there was a significant positive correlation between Lactobacillus and valeraldehyde,1-hexanol,ethyl palmitate,propyl acetate,2-methoxy-4-methylphenol.These results suggest that the aroma quality of fermented bamboo shoots may be seriously affected by the bacterial biota in traditional fermented bamboo shoots.To sum up,this study provides a comprehensive and in-depth correlation between bacterial community and VOCs in fermented bamboo shoots.