Measurement-device-independent quantum key distribution （MDI-QKD） can be immune to all detector side- channel attacks and guarantee the information-theoretical security even with uncharacterized single photon detect...Measurement-device-independent quantum key distribution （MDI-QKD） can be immune to all detector side- channel attacks and guarantee the information-theoretical security even with uncharacterized single photon detectors. MDI-QKD has been demonstrated in both laboratories and field-tests by using attenuated lasers combined with the decoy-state technique. However, it is a critical assumption that the sources used by legitimate participants are trusted in MDI-QKD. Hence, it is possible that a potential security risk exists. Here we propose a new scheme of polarization-encoding-based MDI-QKD with a single untrusted source, by which the complexity of the synchronization system can be reduced and the success rate of the Bell-state measurement can be improved. Meanwhile, the decoy-state method is employed to avoid the security issues introduced by a non-ideal single photon source. We also derive a security analysis of the proposed system. In addition, it seems to be a promising candidate for the implementation for QKD network in the near future.展开更多
Reference-frame-independent（RFI）quantum key distribution（QKD）is a protocol which can share unconditional secret keys between two remote users without the alignment of slowly varying reference frames.We propose a p...Reference-frame-independent（RFI）quantum key distribution（QKD）is a protocol which can share unconditional secret keys between two remote users without the alignment of slowly varying reference frames.We propose a passive decoy-state RFI-QKD protocol with heralded single-photon source（HSPS）and present its security analysis.Compared with RFI QKD using a weak coherent pulse source（WCPS）,numerical simulations show that the passive decoy-state RFI QKD with HSPS performs better not only in secret key rate but also in secure transmission distance.Moreover,our protocol is robust against the relative motion of the reference frames as well as RFI QKD with the WCPS.In addition,we also exploit Hoeffding＇s inequality to investigate the finite-key effect on the security of the protocol.展开更多
Recently, a novel kind of quantum key distribution called the round-robin differential phase-shift （RRDPS） protocol was proposed, which bounds the amount of leakage without monitoring signal disturbance. The protoco...Recently, a novel kind of quantum key distribution called the round-robin differential phase-shift （RRDPS） protocol was proposed, which bounds the amount of leakage without monitoring signal disturbance. The protocol can be implemented by a weak coherent source. The security of this protocol with a simply characterized source has been proved. The application of a common phase shift can improve the secret key rate of the protocol. In practice, the randomized phase is discrete and the secret key rate is deviated from the continuous case. In this study, we analyze security of the RRDPS protocol with discrete-phase-randomized coherent state source and bound the secret key rate. We fix the length of each packet at 32 and 64, then simulate the secret key rates of the RRDPS protocol with discrete-phase randomization and continuous-phase randomization. Our simulation results show that the performance of the discrete-phase randomization case is close to the continuous counterpart with only a small number of discrete phases. The research is practically valuable for experimental implementation.展开更多
To ensure the safety of urban rail transit operations and uncover the transmission dynam ics of risk sources,a key risk chain mining method for urban rail transit operation is pro posed.Firstly,the H-Apriori associati...To ensure the safety of urban rail transit operations and uncover the transmission dynam ics of risk sources,a key risk chain mining method for urban rail transit operation is pro posed.Firstly,the H-Apriori association rule algorithm is proposed for the characteristics of low frequency but high riskiness of high hazard degree risk sources in urban rail transit operation,which adds a new hazard degree evaluation index to the traditional Apriori algo rithm and couples with support degree two-dimensionally to mine the strong association rules among risk sources.Secondly,we construct a weighted risk network with risk sources as network nodes and strong association rules as network edges,and propose a key risk chain mining method for urban rail transit operation based on path search theory to mine key risk chains from the weighted risk network.Finally,using the actual urban rail transit operation data of a city in China as an example,a total of 17 key risk chains are mined,and then 5 key risk sources and 8 key chain break locations are obtained by riskiness and fre quency analysis of key risk chains,and control plans are proposed.The research outcomes introduce a novel approach to mining risk chains in urban rail transit operations,shedding light on the propagation mechanisms,triggering probabilities,and degrees of unsafety associated with risk sources.The results not only provide theoretical support but also offer methodological guidance for pinpointing locations of risk chain breaks and refining the control of risk sources.展开更多
This study evaluates the greenhouse gas(GHG)emissions associated with the construction of subway tunnels,aiming to identify the primary sources of emissions and provide insights into emission reduction strategies.Usin...This study evaluates the greenhouse gas(GHG)emissions associated with the construction of subway tunnels,aiming to identify the primary sources of emissions and provide insights into emission reduction strategies.Using the civil engineering construction of specific tunnels of a subway line in Guangdong Province,China,as a case study,this research quantitatively analyzes the composition of GHG emissions across three stages:upstream building materials production,building materials transportation,and on-site construction.The results indicate that upstream building materials production and on-site construction collectively account for over 95%of the total GHG emissions during tunnel construction.The analysis further reveals that a small proportion of building materials and construction machinery accounts for the majority of total GHG emissions during tunnel construction,aligning with the Pareto principle.The findings emphasize the importance of accurate evaluation of high-impact building materials and construction machinery,particularly in contexts where basic energy consumption data are limited.Strategies such as utilizing recycled materials and enhancing machinery efficiency can lead to significant emission reductions.For instance,achieving a recycling rate of 10%to 30%for steel and concrete can reduce total GHG emissions from tunnel construction by 5.51%to 9.94%,while improving machinery efficiency by 10%to 30%can reduce emissions by up to 2.29%.These findings provide a scientific basis for low-carbon subway tunnel construction.展开更多
基金Supported by the National Natural Science Foundation of China under Grant Nos 61372076 and 61301171the 111 Project under Grant No B08038
文摘Measurement-device-independent quantum key distribution （MDI-QKD） can be immune to all detector side- channel attacks and guarantee the information-theoretical security even with uncharacterized single photon detectors. MDI-QKD has been demonstrated in both laboratories and field-tests by using attenuated lasers combined with the decoy-state technique. However, it is a critical assumption that the sources used by legitimate participants are trusted in MDI-QKD. Hence, it is possible that a potential security risk exists. Here we propose a new scheme of polarization-encoding-based MDI-QKD with a single untrusted source, by which the complexity of the synchronization system can be reduced and the success rate of the Bell-state measurement can be improved. Meanwhile, the decoy-state method is employed to avoid the security issues introduced by a non-ideal single photon source. We also derive a security analysis of the proposed system. In addition, it seems to be a promising candidate for the implementation for QKD network in the near future.
基金Supported by the National Basic Research Program of China under Grant No 2013CB338002the National Natural Science Foundation of China under Grant Nos 61505261,61675235,61605248 and 11304397
文摘Reference-frame-independent（RFI）quantum key distribution（QKD）is a protocol which can share unconditional secret keys between two remote users without the alignment of slowly varying reference frames.We propose a passive decoy-state RFI-QKD protocol with heralded single-photon source（HSPS）and present its security analysis.Compared with RFI QKD using a weak coherent pulse source（WCPS）,numerical simulations show that the passive decoy-state RFI QKD with HSPS performs better not only in secret key rate but also in secure transmission distance.Moreover,our protocol is robust against the relative motion of the reference frames as well as RFI QKD with the WCPS.In addition,we also exploit Hoeffding＇s inequality to investigate the finite-key effect on the security of the protocol.
基金Supported by the National Basic Research Program of China under Grant No 2013CB338002the National Natural Science Foundation of China under Grant Nos 11304397 and 61505261
文摘Recently, a novel kind of quantum key distribution called the round-robin differential phase-shift （RRDPS） protocol was proposed, which bounds the amount of leakage without monitoring signal disturbance. The protocol can be implemented by a weak coherent source. The security of this protocol with a simply characterized source has been proved. The application of a common phase shift can improve the secret key rate of the protocol. In practice, the randomized phase is discrete and the secret key rate is deviated from the continuous case. In this study, we analyze security of the RRDPS protocol with discrete-phase-randomized coherent state source and bound the secret key rate. We fix the length of each packet at 32 and 64, then simulate the secret key rates of the RRDPS protocol with discrete-phase randomization and continuous-phase randomization. Our simulation results show that the performance of the discrete-phase randomization case is close to the continuous counterpart with only a small number of discrete phases. The research is practically valuable for experimental implementation.
文摘To ensure the safety of urban rail transit operations and uncover the transmission dynam ics of risk sources,a key risk chain mining method for urban rail transit operation is pro posed.Firstly,the H-Apriori association rule algorithm is proposed for the characteristics of low frequency but high riskiness of high hazard degree risk sources in urban rail transit operation,which adds a new hazard degree evaluation index to the traditional Apriori algo rithm and couples with support degree two-dimensionally to mine the strong association rules among risk sources.Secondly,we construct a weighted risk network with risk sources as network nodes and strong association rules as network edges,and propose a key risk chain mining method for urban rail transit operation based on path search theory to mine key risk chains from the weighted risk network.Finally,using the actual urban rail transit operation data of a city in China as an example,a total of 17 key risk chains are mined,and then 5 key risk sources and 8 key chain break locations are obtained by riskiness and fre quency analysis of key risk chains,and control plans are proposed.The research outcomes introduce a novel approach to mining risk chains in urban rail transit operations,shedding light on the propagation mechanisms,triggering probabilities,and degrees of unsafety associated with risk sources.The results not only provide theoretical support but also offer methodological guidance for pinpointing locations of risk chain breaks and refining the control of risk sources.
基金funded by the Sichuan Transportation Science and Technology Project(Project No.2021-ZL-04)the Educational Science Research Project of China Transportation Education Research Association(Project Nos.JT2022YB163,and JT2022YB405)Nagqu City Regional Collaborative Innovation Project“Research on Low-Carbon Construction and Safety Control Technologies for Utility Tunnels under Complex Climate and Permafrost Conditions in Ultra-High Altitude Areas of Nagqu”.
文摘This study evaluates the greenhouse gas(GHG)emissions associated with the construction of subway tunnels,aiming to identify the primary sources of emissions and provide insights into emission reduction strategies.Using the civil engineering construction of specific tunnels of a subway line in Guangdong Province,China,as a case study,this research quantitatively analyzes the composition of GHG emissions across three stages:upstream building materials production,building materials transportation,and on-site construction.The results indicate that upstream building materials production and on-site construction collectively account for over 95%of the total GHG emissions during tunnel construction.The analysis further reveals that a small proportion of building materials and construction machinery accounts for the majority of total GHG emissions during tunnel construction,aligning with the Pareto principle.The findings emphasize the importance of accurate evaluation of high-impact building materials and construction machinery,particularly in contexts where basic energy consumption data are limited.Strategies such as utilizing recycled materials and enhancing machinery efficiency can lead to significant emission reductions.For instance,achieving a recycling rate of 10%to 30%for steel and concrete can reduce total GHG emissions from tunnel construction by 5.51%to 9.94%,while improving machinery efficiency by 10%to 30%can reduce emissions by up to 2.29%.These findings provide a scientific basis for low-carbon subway tunnel construction.
