The blockchain provides a reliable and scalable method for enabling source-tracing functionality in large-scale Internet of Things(IoT)systems.Traditional blockchain-based source tracing applications are generally bas...The blockchain provides a reliable and scalable method for enabling source-tracing functionality in large-scale Internet of Things(IoT)systems.Traditional blockchain-based source tracing applications are generally based on the hypothesis that the raw data collected by each IoT node are credible and consistent,which however may not always be the truth.As no mechanism ensures the reliability of the original data collected from the IoT devices,these data may be accidently screwed up or maliciously tampered with before they are uploaded on-chain.To address this issue,we propose the Multi-dimensional Certificates of Origin(MCO)method to filter out the potentially incredible data-till all the data uploaded to the chain are credible.To achieve this,we devise the Multidimensional Information Cross-Verification(MICV)and Multi-source Data Matching Calculation(MDMC)methods.MICV verifies whether a to-be-uploaded datum is consistent or credible,and MDMC determines which data should be discarded and which data should be kept to retain the most likely credible/untampered ones in the circumstance when data inconsistency appears.Large-scale experiments show that our scheme ensures on the credibility of data and off the chain with an affordable overhead.展开更多
Transverse mode instability(TMI)has become the major limitation for power scaling of fiber lasers with nearly diffraction-limited beam quality.Compared with a co-pumped fiber laser,a counter-pumped fiber laser reveals...Transverse mode instability(TMI)has become the major limitation for power scaling of fiber lasers with nearly diffraction-limited beam quality.Compared with a co-pumped fiber laser,a counter-pumped fiber laser reveals TMI threshold enhancement through a semi-analytical model calculation.We demonstrated a 2 kW high-power counter-pumped all-fiberized laser without observation of TMI.Compared with the co-pumped scheme,the TMI threshold is enhanced at least 50%in counter-pumped scheme,moreover,stimulated Raman scattering and four-wave mixing are suppressed simultaneously.展开更多
基金This study is supported by Foundation of National Natural Science Foundation of China(Grant Number:62072273,72111530206,61962009,61873117,61832012,61771231,61771289)Natural Science Foundation of Shandong Province(ZR2019MF062)+3 种基金Shandong University Science and Technology Program Project(J18A326)Guangxi Key Laboratory of Cryptography and Information Security(No:GCIS202112)The Major Basic Research Project of Natural Science Foundation of Shandong Province of China(ZR2018ZC0438)Major Scientific and Technological Special Project of Guizhou Province(20183001),Foundation of Guizhou Provincial Key Laboratory of Public Big Data(No.2019BDKFJJ009),Talent project of Guizhou Big Data Academy.Guizhou Provincial Key Laboratory of Public Big Data.([2018]01).
文摘The blockchain provides a reliable and scalable method for enabling source-tracing functionality in large-scale Internet of Things(IoT)systems.Traditional blockchain-based source tracing applications are generally based on the hypothesis that the raw data collected by each IoT node are credible and consistent,which however may not always be the truth.As no mechanism ensures the reliability of the original data collected from the IoT devices,these data may be accidently screwed up or maliciously tampered with before they are uploaded on-chain.To address this issue,we propose the Multi-dimensional Certificates of Origin(MCO)method to filter out the potentially incredible data-till all the data uploaded to the chain are credible.To achieve this,we devise the Multidimensional Information Cross-Verification(MICV)and Multi-source Data Matching Calculation(MDMC)methods.MICV verifies whether a to-be-uploaded datum is consistent or credible,and MDMC determines which data should be discarded and which data should be kept to retain the most likely credible/untampered ones in the circumstance when data inconsistency appears.Large-scale experiments show that our scheme ensures on the credibility of data and off the chain with an affordable overhead.
基金National Natural Science Foundation of China(NSFC)(11174085,11404305,11474257,51132004,51302086)China State 863 Hi-tech Program(2013AA031502,2014AA041902)+1 种基金Guangdong Natural Science Foundation(S20120011380)China National Funds for Distinguished Young Scientists(61325024)
文摘Transverse mode instability(TMI)has become the major limitation for power scaling of fiber lasers with nearly diffraction-limited beam quality.Compared with a co-pumped fiber laser,a counter-pumped fiber laser reveals TMI threshold enhancement through a semi-analytical model calculation.We demonstrated a 2 kW high-power counter-pumped all-fiberized laser without observation of TMI.Compared with the co-pumped scheme,the TMI threshold is enhanced at least 50%in counter-pumped scheme,moreover,stimulated Raman scattering and four-wave mixing are suppressed simultaneously.
