The m series with 511 bits is taken as an example being applied in non-coherent integra- tion algorithm. A method to choose the bi-phase code is presented, which is 15 kinds of codes are picked out of 511 kinds of m s...The m series with 511 bits is taken as an example being applied in non-coherent integra- tion algorithm. A method to choose the bi-phase code is presented, which is 15 kinds of codes are picked out of 511 kinds of m series to do non-coherent integration. It is indicated that the power in- creasing times of larger target sidelobe is less than the power increasing times of smaller target main- lobe because of the larger target＇ s pseudo-randomness. Smaller target is integrated from larger tar- get sidelobe, which strengthens the detection capability of radar for smaller targets. According to the sidelobes distributing characteristic, a method is presented in this paper to remove the estimated sidelobes mean value for signal detection after non-coherent integration. Simulation results present that the SNR of small target can be improved approximately 6. 5 dB by the proposed method.展开更多
Offboard active decoys(OADs)can effectively jam monopulse radars.However,for missiles approaching from a particular direction and distance,the OAD should be placed at a specific location,posing high requirements for t...Offboard active decoys(OADs)can effectively jam monopulse radars.However,for missiles approaching from a particular direction and distance,the OAD should be placed at a specific location,posing high requirements for timing and deployment.To improve the response speed and jamming effect,a cluster of OADs based on an unmanned surface vehicle(USV)is proposed.The formation of the cluster determines the effectiveness of jamming.First,based on the mechanism of OAD jamming,critical conditions are identified,and a method for assessing the jamming effect is proposed.Then,for the optimization of the cluster formation,a mathematical model is built,and a multi-tribe adaptive particle swarm optimization algorithm based on mutation strategy and Metropolis criterion(3M-APSO)is designed.Finally,the formation optimization problem is solved and analyzed using the 3M-APSO algorithm under specific scenarios.The results show that the improved algorithm has a faster convergence rate and superior performance as compared to the standard Adaptive-PSO algorithm.Compared with a single OAD,the optimal formation of USV-OAD cluster effectively fills the blind area and maximizes the use of jamming resources.展开更多
In this paper, we propose a measurement-device-independent quantum-key-distribution（MDI-QKD） protocol using orbital angular momentum（OAM） in free space links, named the OAM-MDI-QKD protocol. In the proposed protoc...In this paper, we propose a measurement-device-independent quantum-key-distribution（MDI-QKD） protocol using orbital angular momentum（OAM） in free space links, named the OAM-MDI-QKD protocol. In the proposed protocol,the OAM states of photons, instead of polarization states, are used as the information carriers to avoid the reference frame alignment, the decoy-state is adopted to overcome the security loophole caused by the weak coherent pulse source, and the high efficient OAM-sorter is adopted as the measurement tool for Charlie to obtain the output OAM state. Here, Charlie may be an untrusted third party. The results show that the authorized users, Alice and Bob, could distill a secret key with Charlie＇s successful measurements, and the key generation performance is slightly better than that of the polarization-based MDI-QKD protocol in the two-dimensional OAM cases. Simultaneously, Alice and Bob can reduce the number of flipping the bits in the secure key distillation. It is indicated that a higher key generation rate performance could be obtained by a high dimensional OAM-MDI-QKD protocol because of the unlimited degree of freedom on OAM states. Moreover,the results show that the key generation rate and the transmission distance will decrease as the growth of the strength of atmospheric turbulence（AT） and the link attenuation. In addition, the decoy states used in the proposed protocol can get a considerable good performance without the need for an ideal source.展开更多
Recently the performance of the quantum key distribution （QKD） is substantially improved by the decoy state method and the non-orthogonal encoding protocol, separately. In this paper, a practical non-orthogonal deco...Recently the performance of the quantum key distribution （QKD） is substantially improved by the decoy state method and the non-orthogonal encoding protocol, separately. In this paper, a practical non-orthogonal decoy state protocol with a heralded single photon source （HSPS） for QKD is presented. The protocol is based on 4 states with different intensities. i.e. one signal state and three decoy states. The signal state is for generating keys; the decoy states are for detecting the eavesdropping and estimating the fraction of single-photon and two-photon pulses. We have discussed three cases of this protocol, i.e. the general case, the optimal case and the special case. Moreover, the final key rate over transmission distance is simulated. For the low dark count of the HSPS and the utilization of the two-photon pulses, our protocol has a higher key rate and a longer transmission distance than any other decoy state protocol.展开更多
We investigate the decoy state quantum key distribution via the atmosphere channels. We consider the efficient decoy state method with one-signal state and two-decoy states. Our results show that the decoy state metho...We investigate the decoy state quantum key distribution via the atmosphere channels. We consider the efficient decoy state method with one-signal state and two-decoy states. Our results show that the decoy state method works even in the channels with fluctuating transmittance. Nevertheless, the key generation rate will be dra-matically decreased by atmosphere turbulence, which sheds more light on the characterization of atmosphere turbulence in realistic free-space based quantum key distributions.展开更多
The quantum key distribution （QKD） allows two parties to share a secret key by typically making use of a one-way quantum channel. Howevery the two-way QKD has its own unique advantages, which means the two-way QKD h...The quantum key distribution （QKD） allows two parties to share a secret key by typically making use of a one-way quantum channel. Howevery the two-way QKD has its own unique advantages, which means the two-way QKD has become a focus recently. To improve the practieM performance of the two-way QKD, we present a security analysis of a two-way QKD protocol based on the decoy method with heralded single-photon sources （HSPSs）. We make use of two approaches to calculate the yield and the quantum bit error rate of single-photon and two-photon pulses. Then we present the secret key generation rate based on the GLLP formula. The numerical simulation shows that the protocol with HSPSs has an advantage in the secure distance compared with weak coherent state sources. In addition, we present the final secret key by considering the statistical fluctuation of the yield generation rate of the LM05 protocol with finite resources and the error rate.展开更多
Reference-frame-independent quantum key distribution(RFI-QKD)has been proven to be very useful and practical under realistic environment.Here,we present a scheme for one-decoy state RFI-QKD based on the work of Rusca ...Reference-frame-independent quantum key distribution(RFI-QKD)has been proven to be very useful and practical under realistic environment.Here,we present a scheme for one-decoy state RFI-QKD based on the work of Rusca et al.[Appl.Phys.Lett.112,171104(2018)],and carry out investigation on its performance under realistic experimental conditions.Numerical simulation results show that the one-decoy state RFI-QKD can achieve comparable performance in terms of secret key rate and transmission distance as the two-decoy state correspondence under practical experimental conditions.On contrast,it does not need to prepare the vacuum state in the former case,substantially reducing the experimental complexity and random number consumptions.Therefore,our present proposal seems very promising in practical implementations of RFI-QKD.展开更多
We generalize BB84 quantum key distribution(QKD) to the scenario where the receiver adopts a heralded quantum memory(QM). With the heralded QM, the valid dark count rate of the receiver's single photon detectors c...We generalize BB84 quantum key distribution(QKD) to the scenario where the receiver adopts a heralded quantum memory(QM). With the heralded QM, the valid dark count rate of the receiver's single photon detectors can be mitigated obviously, which will lower the quantum bit error rate, and thus improve the performance of decoy-state BB84 QKD systems in long distance range. Simulation results show that, with practical experimental system parameters, decoy-state BB84 QKD with QM can exhibit performance comparable to that of without QM in short distance range, and exhibit performance better than that without QM in long distance range.展开更多
Passive decoy-state quantum key distribution is more desirable than the active one in some scenarios. It is also affected by the imperfections of the devices. In this paper, the influence of modulator attenuation on t...Passive decoy-state quantum key distribution is more desirable than the active one in some scenarios. It is also affected by the imperfections of the devices. In this paper, the influence of modulator attenuation on the passive decoy-state method is considered. We introduce and analyze the unbalanced Mach-Zehnder interferometer, briefly, and combining with the virtual source and imaginary unitary transformation, we characterize the passive decoy-state method using a weak coherent photon source with modulator attenuation. According to the attenuation parameter 6, the pass efficiencies are given. Then, the key generation rate can be acquired. From numerical simulations, it can be seen that modulator attenuation has a non- negligible influence on the performance of passive-state QKD protocol. Based on the research, the analysis method of virtual source and imaginary unitary transformation are preferred in analyzing passive decoy state protocol, and the passive decoy-state method is better than the active one and is close to the active vacuum ＋ weak decoy state under the condition of having the same modulator attenuation.展开更多
Quantum key distribution provides an unconditional secure key sharing method in theory,but the imperfect factors of practical devices will bring security vulnerabilities.In this paper,we characterize the imperfections...Quantum key distribution provides an unconditional secure key sharing method in theory,but the imperfect factors of practical devices will bring security vulnerabilities.In this paper,we characterize the imperfections of the sender and analyze the possible attack strategies of Eve.Firstly,we present a quantized model for distinguishability of decoy states caused by intensity modulation.Besides,considering that Eve may control the preparation of states through hidden variables,we evaluate the security of preparation in practical quantum key distribution(QKD)scheme based on the weak-randomness model.Finally,we analyze the influence of the distinguishability of decoy state to secure key rate,for Eve may conduct the beam splitting attack and control the channel attenuation of different parts.Through the simulation,it can be seen that the secure key rate is sensitive to the distinguishability of decoy state and weak randomness,especially when Eve can control the channel attenuation.展开更多
The existing decoy-state quantum key distribution(QKD)beating photon-number-splitting(PNS)attack provides a more accurate method to estimate the secure key rate,while it still considers that only single-photon pulses ...The existing decoy-state quantum key distribution(QKD)beating photon-number-splitting(PNS)attack provides a more accurate method to estimate the secure key rate,while it still considers that only single-photon pulses can generate secure keys in any case.However,multiphoton pulses can also generate secure keys if we can detect the possibility of PNS attack in the channel.The ultimate goal of this line of research is to confirm the absence of all types of PNS attacks.In particular,the PNS attack mentioned and detected in this paper is only the weaker version of PNS attack which significantly changes the observed values of the legitimate users.In this paper,under the null hypothesis of no weaker version of PNS attack,we first determine whether there is an attack or not by retrieving the missing information of the existing decoy-state protocols,extract a Cauchy distribution statistic,and further provide a detection method and the type I error probability.If the result is judged to be an attack,we can use the existing decoy-state method and the GLLP formula to estimate the secure key rate.Otherwise,the pulses with the same basis received including both single-photon pulses and multiphoton pulses,can be used to generate the keys and we give the secure key rate in this case.Finally,the associated experiments we performed(i.e.,the significance level is 5%)show the correctness of our method.展开更多
Passive decoy state quantum key distribution（PDS-QKD） has advantages in high-speed scenarios.We propose a modified model to simulate the PDS-QKD with a weak coherent light source based on Curty＇s theory [Opt.Lett.3...Passive decoy state quantum key distribution（PDS-QKD） has advantages in high-speed scenarios.We propose a modified model to simulate the PDS-QKD with a weak coherent light source based on Curty＇s theory [Opt.Lett.34 3238（2009）].The modified model can provide better performance in a practical PDS-QKD system.Moreover,we report an experimental demonstration of the PDS-QKD of over 22.0-dB channel loss.展开更多
Phase-matching quantum key distribution is a promising scheme for remote quantum key distribution,breaking through the traditional linear key-rate bound.In practical applications,finite data size can cause significant...Phase-matching quantum key distribution is a promising scheme for remote quantum key distribution,breaking through the traditional linear key-rate bound.In practical applications,finite data size can cause significant system performance to deteriorate when data size is below 1010.In this work,an improved statistical fluctuation analysis method is applied for the first time to two decoy-states phase-matching quantum key distribution,offering a new insight and potential solutions for improving the key generation rate and the maximum transmission distance while maintaining security.Moreover,we also compare the influence of the proposed improved statistical fluctuation analysis method on system performance with those of the Gaussian approximation and Chernoff-Hoeffding boundary methods on system performance.The simulation results show that the proposed scheme significantly improves the key generation rate and maximum transmission distance in comparison with the Chernoff-Hoeffding approach,and approach the results obtained when the Gaussian approximation is employed.At the same time,the proposed scheme retains the same security level as the Chernoff-Hoeffding method,and is even more secure than the Gaussian approximation.展开更多
Taken guidance radar as an example,some evaluation models for number of shot,single-shot kill probability and damage ability are established firstly.Then tactics calculation methods for number of anti-radar reflector ...Taken guidance radar as an example,some evaluation models for number of shot,single-shot kill probability and damage ability are established firstly.Then tactics calculation methods for number of anti-radar reflector beam,throwing time interval and total consumption are given.Finally,the models' feasibility is illustrated with a numerical example and some valuable conclusions are drawn.展开更多
Passive decoy state quantum key distribution(PDS-QKD) has advantages in high-speed scenarios.We propose a modified model to simulate the PDS-QKD with a weak coherent light source based on Curty’s theory [Opt.Lett.34 ...Passive decoy state quantum key distribution(PDS-QKD) has advantages in high-speed scenarios.We propose a modified model to simulate the PDS-QKD with a weak coherent light source based on Curty’s theory [Opt.Lett.34 3238(2009)].The modified model can provide better performance in a practical PDS-QKD system.Moreover,we report an experimental demonstration of the PDS-QKD of over 22.0-dB channel loss.展开更多
Innate immune signaling is essential for clearing pathogens and damaged cells and must be tightly regulated to avoid excessive inflammation or autoimmunity.Here,we found that the alternative splicing of exons derived ...Innate immune signaling is essential for clearing pathogens and damaged cells and must be tightly regulated to avoid excessive inflammation or autoimmunity.Here,we found that the alternative splicing of exons derived from transposable elements is a key mechanism controlling immune signaling in human cells.By analyzing long-read transcriptome datasets,we identified numerous transposon exonization events predicted to generate functional protein variants of immune genes,including the type I interferon receptor IFNAR2.We demonstrated that the transposon-derived isoform of IFNAR2 is more highly expressed than the canonical isoform in almost all tissues and functions as a decoy receptor that potently inhibits interferon signaling,including in cells infected with severe acute respiratory syndrome coronavirus 2(SARS-CoV-2).Our findings uncover a primate-specific axis controlling interferon signaling and show how a transposon exonization event can be co-opted for immune regulation.展开更多
It is difficult to achieve accurate acquisition of weak global positioning system( GPS) signals with traditional methods. A weak signal acquisition strategy based on block processing and differentially coherent( BPDC)...It is difficult to achieve accurate acquisition of weak global positioning system( GPS) signals with traditional methods. A weak signal acquisition strategy based on block processing and differentially coherent( BPDC) is put forward after analyzing the advantages and disadvantages of coherent and non-coherent integration algorithms. Code phase parallel search of the pre-coherent integration is conducted by using fast Fourier transform( FFT),and the results are then differential coherent processed and block processed. BPDC method reduces computation cost compared with coherent and noncoherent( CNC) algorithm. The performance of the two algorithms is also compared based on simulated signals. The result shows that the noise suppression effect of BPDC algorithms is superior to that of traditional CNC algorithm,and the superiority of BPDC is more apparent with the reduction of carrier to noise ratio( CNR). In the case that the pre-coherent integration length is 4 ms and CNR is reduced to 28 dB-Hz,CNC algorithm cannot yet acquire signal correctly while BPDC has well acquisition performance. Therefore,for weak GPS signal acquisition,BPDC algorithm can acquire the signal with lower CNR and has better acquisition property.展开更多
基金Supported by the National Natural Science Foundation of China(Youth Science Fund)(61001190)
文摘The m series with 511 bits is taken as an example being applied in non-coherent integra- tion algorithm. A method to choose the bi-phase code is presented, which is 15 kinds of codes are picked out of 511 kinds of m series to do non-coherent integration. It is indicated that the power in- creasing times of larger target sidelobe is less than the power increasing times of smaller target main- lobe because of the larger target＇ s pseudo-randomness. Smaller target is integrated from larger tar- get sidelobe, which strengthens the detection capability of radar for smaller targets. According to the sidelobes distributing characteristic, a method is presented in this paper to remove the estimated sidelobes mean value for signal detection after non-coherent integration. Simulation results present that the SNR of small target can be improved approximately 6. 5 dB by the proposed method.
基金the National Natural Science Foundation of China(Grant No.62101579).
文摘Offboard active decoys(OADs)can effectively jam monopulse radars.However,for missiles approaching from a particular direction and distance,the OAD should be placed at a specific location,posing high requirements for timing and deployment.To improve the response speed and jamming effect,a cluster of OADs based on an unmanned surface vehicle(USV)is proposed.The formation of the cluster determines the effectiveness of jamming.First,based on the mechanism of OAD jamming,critical conditions are identified,and a method for assessing the jamming effect is proposed.Then,for the optimization of the cluster formation,a mathematical model is built,and a multi-tribe adaptive particle swarm optimization algorithm based on mutation strategy and Metropolis criterion(3M-APSO)is designed.Finally,the formation optimization problem is solved and analyzed using the 3M-APSO algorithm under specific scenarios.The results show that the improved algorithm has a faster convergence rate and superior performance as compared to the standard Adaptive-PSO algorithm.Compared with a single OAD,the optimal formation of USV-OAD cluster effectively fills the blind area and maximizes the use of jamming resources.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61271238 and 61475075)the Specialized Research Fund for the Doctoral Program of Higher Education of China(Grant No.20123223110003)+7 种基金the Natural Science Research Foundation for Universities of Jiangsu Province of China(Grant No.11KJA510002)the Open Research Fund of Key Laboratory of Broadband Wireless Communication and Sensor Network TechnologyMinistry of EducationChina(Grant No.NYKL2015011)the Innovation Program of Graduate Education of Jiangsu ProvinceChina(Grant No.KYLX0810)partially supported by Qinglan Project of Jiangsu ProvinceChina
文摘In this paper, we propose a measurement-device-independent quantum-key-distribution（MDI-QKD） protocol using orbital angular momentum（OAM） in free space links, named the OAM-MDI-QKD protocol. In the proposed protocol,the OAM states of photons, instead of polarization states, are used as the information carriers to avoid the reference frame alignment, the decoy-state is adopted to overcome the security loophole caused by the weak coherent pulse source, and the high efficient OAM-sorter is adopted as the measurement tool for Charlie to obtain the output OAM state. Here, Charlie may be an untrusted third party. The results show that the authorized users, Alice and Bob, could distill a secret key with Charlie＇s successful measurements, and the key generation performance is slightly better than that of the polarization-based MDI-QKD protocol in the two-dimensional OAM cases. Simultaneously, Alice and Bob can reduce the number of flipping the bits in the secure key distillation. It is indicated that a higher key generation rate performance could be obtained by a high dimensional OAM-MDI-QKD protocol because of the unlimited degree of freedom on OAM states. Moreover,the results show that the key generation rate and the transmission distance will decrease as the growth of the strength of atmospheric turbulence（AT） and the link attenuation. In addition, the decoy states used in the proposed protocol can get a considerable good performance without the need for an ideal source.
基金Project supported by the National Natural Science Foundation of China (Grant No 60578055)the State Key Development Program for Basic Research of China (Grant No 2007CB307001)
文摘Recently the performance of the quantum key distribution （QKD） is substantially improved by the decoy state method and the non-orthogonal encoding protocol, separately. In this paper, a practical non-orthogonal decoy state protocol with a heralded single photon source （HSPS） for QKD is presented. The protocol is based on 4 states with different intensities. i.e. one signal state and three decoy states. The signal state is for generating keys; the decoy states are for detecting the eavesdropping and estimating the fraction of single-photon and two-photon pulses. We have discussed three cases of this protocol, i.e. the general case, the optimal case and the special case. Moreover, the final key rate over transmission distance is simulated. For the low dark count of the HSPS and the utilization of the two-photon pulses, our protocol has a higher key rate and a longer transmission distance than any other decoy state protocol.
基金Supported by the National Natural Science Foundation of China under Grant Nos 11574400,U1304613,11204197,11204379 and 11074244the National Basic Research Program of China under Grant No 2011CBA00200the Doctor Foundation of the Ministry of Education of China under Grant No 20113402110059
文摘We investigate the decoy state quantum key distribution via the atmosphere channels. We consider the efficient decoy state method with one-signal state and two-decoy states. Our results show that the decoy state method works even in the channels with fluctuating transmittance. Nevertheless, the key generation rate will be dra-matically decreased by atmosphere turbulence, which sheds more light on the characterization of atmosphere turbulence in realistic free-space based quantum key distributions.
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The quantum key distribution （QKD） allows two parties to share a secret key by typically making use of a one-way quantum channel. Howevery the two-way QKD has its own unique advantages, which means the two-way QKD has become a focus recently. To improve the practieM performance of the two-way QKD, we present a security analysis of a two-way QKD protocol based on the decoy method with heralded single-photon sources （HSPSs）. We make use of two approaches to calculate the yield and the quantum bit error rate of single-photon and two-photon pulses. Then we present the secret key generation rate based on the GLLP formula. The numerical simulation shows that the protocol with HSPSs has an advantage in the secure distance compared with weak coherent state sources. In addition, we present the final secret key by considering the statistical fluctuation of the yield generation rate of the LM05 protocol with finite resources and the error rate.
基金Project supported by the National Key Research and Development Program of China(Grant Nos.2018YFA0306400 and 2017YFA0304100)the National Natural Science Foundation of China(Grant Nos.61590932,11774180,and 61705110)the Natural Science Foundation of Jiangsu Province for Leading-edge Technology Program,China(Grant No.BK20192001).
文摘Reference-frame-independent quantum key distribution(RFI-QKD)has been proven to be very useful and practical under realistic environment.Here,we present a scheme for one-decoy state RFI-QKD based on the work of Rusca et al.[Appl.Phys.Lett.112,171104(2018)],and carry out investigation on its performance under realistic experimental conditions.Numerical simulation results show that the one-decoy state RFI-QKD can achieve comparable performance in terms of secret key rate and transmission distance as the two-decoy state correspondence under practical experimental conditions.On contrast,it does not need to prepare the vacuum state in the former case,substantially reducing the experimental complexity and random number consumptions.Therefore,our present proposal seems very promising in practical implementations of RFI-QKD.
基金supported by the National Key Research and Development Program of China (Grant Nos. 2018YFA0306400 and 2017YFA0304100)the National Natural Science Foundation of China (Grant Nos. 12074194 and 11774180)the Leading-edge Technology Program of Jiangsu Provincial Natural Science Foundation,China (Grant No. BK20192001)。
文摘We generalize BB84 quantum key distribution(QKD) to the scenario where the receiver adopts a heralded quantum memory(QM). With the heralded QM, the valid dark count rate of the receiver's single photon detectors can be mitigated obviously, which will lower the quantum bit error rate, and thus improve the performance of decoy-state BB84 QKD systems in long distance range. Simulation results show that, with practical experimental system parameters, decoy-state BB84 QKD with QM can exhibit performance comparable to that of without QM in short distance range, and exhibit performance better than that without QM in long distance range.
基金supported by the National Natural Science Foundation of China(Grant No.11304397)
文摘Passive decoy-state quantum key distribution is more desirable than the active one in some scenarios. It is also affected by the imperfections of the devices. In this paper, the influence of modulator attenuation on the passive decoy-state method is considered. We introduce and analyze the unbalanced Mach-Zehnder interferometer, briefly, and combining with the virtual source and imaginary unitary transformation, we characterize the passive decoy-state method using a weak coherent photon source with modulator attenuation. According to the attenuation parameter 6, the pass efficiencies are given. Then, the key generation rate can be acquired. From numerical simulations, it can be seen that modulator attenuation has a non- negligible influence on the performance of passive-state QKD protocol. Based on the research, the analysis method of virtual source and imaginary unitary transformation are preferred in analyzing passive decoy state protocol, and the passive decoy-state method is better than the active one and is close to the active vacuum ＋ weak decoy state under the condition of having the same modulator attenuation.
基金the National Key Research and Development Program of China(Grant No.2020YFA0309702)NSAF(Grant No.U2130205)+3 种基金the National Natural Science Foundation of China(Grant Nos.62101597,61605248,and 61505261)the China Postdoctoral Science Foundation(Grant No.2021M691536)the Natural Science Foundation of Henan(Grant Nos.202300410534 and 202300410532)the Anhui Initiative in Quantum Information Technologies。
文摘Quantum key distribution provides an unconditional secure key sharing method in theory,but the imperfect factors of practical devices will bring security vulnerabilities.In this paper,we characterize the imperfections of the sender and analyze the possible attack strategies of Eve.Firstly,we present a quantized model for distinguishability of decoy states caused by intensity modulation.Besides,considering that Eve may control the preparation of states through hidden variables,we evaluate the security of preparation in practical quantum key distribution(QKD)scheme based on the weak-randomness model.Finally,we analyze the influence of the distinguishability of decoy state to secure key rate,for Eve may conduct the beam splitting attack and control the channel attenuation of different parts.Through the simulation,it can be seen that the secure key rate is sensitive to the distinguishability of decoy state and weak randomness,especially when Eve can control the channel attenuation.
文摘The existing decoy-state quantum key distribution(QKD)beating photon-number-splitting(PNS)attack provides a more accurate method to estimate the secure key rate,while it still considers that only single-photon pulses can generate secure keys in any case.However,multiphoton pulses can also generate secure keys if we can detect the possibility of PNS attack in the channel.The ultimate goal of this line of research is to confirm the absence of all types of PNS attacks.In particular,the PNS attack mentioned and detected in this paper is only the weaker version of PNS attack which significantly changes the observed values of the legitimate users.In this paper,under the null hypothesis of no weaker version of PNS attack,we first determine whether there is an attack or not by retrieving the missing information of the existing decoy-state protocols,extract a Cauchy distribution statistic,and further provide a detection method and the type I error probability.If the result is judged to be an attack,we can use the existing decoy-state method and the GLLP formula to estimate the secure key rate.Otherwise,the pulses with the same basis received including both single-photon pulses and multiphoton pulses,can be used to generate the keys and we give the secure key rate in this case.Finally,the associated experiments we performed(i.e.,the significance level is 5%)show the correctness of our method.
基金Project supported by the National Basic Research Program of China （Grants Nos. 2011CBA00200 and 2011CB921200） the National Natural Science Foundation of China （Grant Nos. 60921091 and 61101137） the China Postdoctoral Science Foundation（Grant Nos. 20100480695 and 2012M511419）
文摘Passive decoy state quantum key distribution（PDS-QKD） has advantages in high-speed scenarios.We propose a modified model to simulate the PDS-QKD with a weak coherent light source based on Curty＇s theory [Opt.Lett.34 3238（2009）].The modified model can provide better performance in a practical PDS-QKD system.Moreover,we report an experimental demonstration of the PDS-QKD of over 22.0-dB channel loss.
文摘Phase-matching quantum key distribution is a promising scheme for remote quantum key distribution,breaking through the traditional linear key-rate bound.In practical applications,finite data size can cause significant system performance to deteriorate when data size is below 1010.In this work,an improved statistical fluctuation analysis method is applied for the first time to two decoy-states phase-matching quantum key distribution,offering a new insight and potential solutions for improving the key generation rate and the maximum transmission distance while maintaining security.Moreover,we also compare the influence of the proposed improved statistical fluctuation analysis method on system performance with those of the Gaussian approximation and Chernoff-Hoeffding boundary methods on system performance.The simulation results show that the proposed scheme significantly improves the key generation rate and maximum transmission distance in comparison with the Chernoff-Hoeffding approach,and approach the results obtained when the Gaussian approximation is employed.At the same time,the proposed scheme retains the same security level as the Chernoff-Hoeffding method,and is even more secure than the Gaussian approximation.
文摘Taken guidance radar as an example,some evaluation models for number of shot,single-shot kill probability and damage ability are established firstly.Then tactics calculation methods for number of anti-radar reflector beam,throwing time interval and total consumption are given.Finally,the models' feasibility is illustrated with a numerical example and some valuable conclusions are drawn.
基金Project supported by the National Basic Research Program of China (Grants Nos. 2011CBA00200 and 2011CB921200)the National Natural Science Foundation of China (Grant Nos. 60921091 and 61101137)the China Postdoctoral Science Foundation(Grant Nos. 20100480695 and 2012M511419)
文摘Passive decoy state quantum key distribution(PDS-QKD) has advantages in high-speed scenarios.We propose a modified model to simulate the PDS-QKD with a weak coherent light source based on Curty’s theory [Opt.Lett.34 3238(2009)].The modified model can provide better performance in a practical PDS-QKD system.Moreover,we report an experimental demonstration of the PDS-QKD of over 22.0-dB channel loss.
文摘Innate immune signaling is essential for clearing pathogens and damaged cells and must be tightly regulated to avoid excessive inflammation or autoimmunity.Here,we found that the alternative splicing of exons derived from transposable elements is a key mechanism controlling immune signaling in human cells.By analyzing long-read transcriptome datasets,we identified numerous transposon exonization events predicted to generate functional protein variants of immune genes,including the type I interferon receptor IFNAR2.We demonstrated that the transposon-derived isoform of IFNAR2 is more highly expressed than the canonical isoform in almost all tissues and functions as a decoy receptor that potently inhibits interferon signaling,including in cells infected with severe acute respiratory syndrome coronavirus 2(SARS-CoV-2).Our findings uncover a primate-specific axis controlling interferon signaling and show how a transposon exonization event can be co-opted for immune regulation.
基金Supported by the Fundamental Research Fund for the Central University(1002-56XAA13016)
文摘It is difficult to achieve accurate acquisition of weak global positioning system( GPS) signals with traditional methods. A weak signal acquisition strategy based on block processing and differentially coherent( BPDC) is put forward after analyzing the advantages and disadvantages of coherent and non-coherent integration algorithms. Code phase parallel search of the pre-coherent integration is conducted by using fast Fourier transform( FFT),and the results are then differential coherent processed and block processed. BPDC method reduces computation cost compared with coherent and noncoherent( CNC) algorithm. The performance of the two algorithms is also compared based on simulated signals. The result shows that the noise suppression effect of BPDC algorithms is superior to that of traditional CNC algorithm,and the superiority of BPDC is more apparent with the reduction of carrier to noise ratio( CNR). In the case that the pre-coherent integration length is 4 ms and CNR is reduced to 28 dB-Hz,CNC algorithm cannot yet acquire signal correctly while BPDC has well acquisition performance. Therefore,for weak GPS signal acquisition,BPDC algorithm can acquire the signal with lower CNR and has better acquisition property.
