Health information spreads rapidly,which can effectively control epidemics.However,the swift dissemination of information also has potential negative impacts,which increasingly attracts attention.Message fatigue refer...Health information spreads rapidly,which can effectively control epidemics.However,the swift dissemination of information also has potential negative impacts,which increasingly attracts attention.Message fatigue refers to the psychological response characterized by feelings of boredom and anxiety that occur after receiving an excessive amount of similar information.This phenomenon can alter individual behaviors related to epidemic prevention.Additionally,recent studies indicate that pairwise interactions alone are insufficient to describe complex social transmission processes,and higher-order structures representing group interactions are crucial.To address this,we develop a novel epidemic model that investigates the interactions between information,behavioral responses,and epidemics.Our model incorporates the impact of message fatigue on the entire transmission system.The information layer is modeled using a static simplicial network to capture group interactions,while the disease layer uses a time-varying network based on activity-driven model with attractiveness to represent the self-protection behaviors of susceptible individuals and self-isolation behaviors of infected individuals.We theoretically describe the co-evolution equations using the microscopic Markov chain approach(MMCA)and get the epidemic threshold.Experimental results show that while the negative impact of message fatigue on epidemic transmission is limited,it significantly weakens the group interactions depicted by higher-order structures.Individual behavioral responses strongly inhibit the epidemic.Our simulations using the Monte Carlo(MC)method demonstrate that greater intensity in these responses leads to clustering of susceptible individuals in the disease layer.Finally,we apply the proposed model to real networks to verify its reliability.In summary,our research results enhance the understanding of the information-epidemic coupling dynamics,and we expect to provide valuable guidance for managing future emerging epidemics.展开更多
Due to the lack of authentication mechanism in BeiDou navigation satellite system(BDS),BD-Ⅱ civil navigation message(BDⅡ-CNAV) are vulnerable to spoofing attack and replay attack.To solve this problem,we present a s...Due to the lack of authentication mechanism in BeiDou navigation satellite system(BDS),BD-Ⅱ civil navigation message(BDⅡ-CNAV) are vulnerable to spoofing attack and replay attack.To solve this problem,we present a security authentication protocol,called as BDSec,which is designed by using China’s cryptography Shangyong Mima(SM) series algorithms,such as SM2/4/9 and Zu Chongzhi(ZUC)algorithm.In BDSec protocol,both of BDⅡ-CNAV and signature information are encrypted using the SM4 algorithm(Symmetric encryption mechanism).The encrypted result is used as the subject authentication information.BDSec protocol applies SM9 algorithm(Identity-based cryptography mechanism) to protect the integrity of the BDⅡ-CNAV,adopts the SM2 algorithm(Public key cryptosystem) to guarantee the confidentiality of the important session information,and uses the ZUC algorithm(Encryption and integrity algorithm) to verify the integrity of the message authentication serial number and initial information and the information in authentication initialization sub-protocol respectively.The results of the SVO logic reasoning and performance analysis show that BDSec protocol meets security requirements for the dual user identity authentication in BDS and can realize the security authentication of BDⅡ-CNAV.展开更多
The BeiDou-Ⅱcivil navigation message(BDⅡ-CNAV)is transmitted in an open environment and no information integrity protection measures are provided.Hence,the BDⅡ-CNAV faces the threat of spoofing attacks,which can le...The BeiDou-Ⅱcivil navigation message(BDⅡ-CNAV)is transmitted in an open environment and no information integrity protection measures are provided.Hence,the BDⅡ-CNAV faces the threat of spoofing attacks,which can lead to wrong location reports and time indication.In order to deal with this threat,we proposed a scheme of anti-spoofing for BDⅡ-CNAV based on integrated information authentication.This scheme generates two type authentication information,one is authentication code information(ACI),which is applied to confirm the authenticity and reliability of satellite time information,and the other is signature information,which is used to authenticate the integrity of satellite location information and other information.Both authentication information is designed to embed into the reserved bits in BDⅡ-CNAV without changing the frame structure.In order to avoid authentication failure caused by public key error or key error,the key or public key prompt information(KPKPI)are designed to remind the receiver to update both keys in time.Experimental results indicate that the scheme can successfully detect spoofing attacks,and the authentication delay is less than 1%of the transmission delay,which meets the requirements of BDⅡ-CNAV information authentication.展开更多
Hybrid precoder design is a key technique providing better antenna gain and reduced hardware complexity in millimeter-wave(mmWave)massive multiple-input multiple-output(MIMO)systems.In this paper,Gaussian Mixture lear...Hybrid precoder design is a key technique providing better antenna gain and reduced hardware complexity in millimeter-wave(mmWave)massive multiple-input multiple-output(MIMO)systems.In this paper,Gaussian Mixture learned approximate message passing(GM-LAMP)network is presented for the design of optimal hybrid precoders suitable for mmWave Massive MIMO systems.Optimal hybrid precoder designs using a compressive sensing scheme such as orthogonal matching pursuit(OMP)and its derivatives results in high computational complexity when the dimensionality of the sparse signal is high.This drawback can be addressed using classical iterative algorithms such as approximate message passing(AMP),which has comparatively low computational complexity.The drawbacks of AMP algorithm are fixed shrinkage parameter and non-consideration of prior distribution of the hybrid precoders.In this paper,the fixed shrinkage parameter problem of the AMP algorithm is addressed using learned AMP(LAMP)network,and is further enhanced as GMLAMP network using the concept of Gaussian Mixture distribution of the hybrid precoders.The simula-tion results show that the proposed GM-LAMP network achieves optimal hybrid precoder design with enhanced achievable rates,better accuracy and low computational complexity compared to the existing algorithms.展开更多
This paper investigates the fundamental data detection problem with burst interference in massive multiple-input multiple-output orthogonal frequency division multiplexing(MIMO-OFDM) systems. In particular, burst inte...This paper investigates the fundamental data detection problem with burst interference in massive multiple-input multiple-output orthogonal frequency division multiplexing(MIMO-OFDM) systems. In particular, burst interference may occur only on data symbols but not on pilot symbols, which means that interference information cannot be premeasured. To cancel the burst interference, we first revisit the uplink multi-user system and develop a matrixform system model, where the covariance pattern and the low-rank property of the interference matrix is discussed. Then, we propose a turbo message passing based burst interference cancellation(TMP-BIC) algorithm to solve the data detection problem, where the constellation information of target data is fully exploited to refine its estimate. Furthermore, in the TMP-BIC algorithm, we design one module to cope with the interference matrix by exploiting its lowrank property. Numerical results demonstrate that the proposed algorithm can effectively mitigate the adverse effects of burst interference and approach the interference-free bound.展开更多
Due to the civil BeiDou navigation system is open,unauthenticated,and non-encrypted,civilian BeiDou navigation signals may have great security loopholes during transmission or reception.The main security loophole here...Due to the civil BeiDou navigation system is open,unauthenticated,and non-encrypted,civilian BeiDou navigation signals may have great security loopholes during transmission or reception.The main security loophole here is spoofing attacks.Spoofing attacks make the positioning or timing results of BeiDou civilian receivers wrong.Such errors may cause a series of security problems,which lays a serious hidden danger for Bei-Dou satellite information security.This article proposes an anti-spoofing method for BeiDou navigation system based on the combination of SM commercial cryptographic algorithm and Timed Efficient Stream Loss-tolerant Authentication(TESLA)for spoofing attacks.In this solution,we use the SM3 algorithm to generate a TESLA key chain with time information,and then use the key in the key chain to generate the message authentication code for the BeiDou D2 navigation message.The message authentication code is inserted into a reserved bit of the D2 navigation message.In addition,this solution uses the SM2 algorithm to protect and encrypt time information in the TESLA key chain to prevent key replay attacks in TESLA.The experimental results tested on the experimental platform built in this paper show that this scheme reduces the possibility of the BeiDou navigation system being deceived and enhances the safety of the BeiDou navigation system.展开更多
The orthogonal time frequency space(OTFS)modulation has emerged as a promis⁃ing modulation scheme for wireless communications in high-mobility scenarios.An efficient detector is of paramount importance to harvesting t...The orthogonal time frequency space(OTFS)modulation has emerged as a promis⁃ing modulation scheme for wireless communications in high-mobility scenarios.An efficient detector is of paramount importance to harvesting the time and frequency diversities promised by OTFS.Recently,some message passing based detectors have been developed by exploiting the features of the OTFS channel matrices.In this paper,we provide an overview of some re⁃cent message passing based OTFS detectors,compare their performance,and shed some light on potential research on the design of message passing based OTFS receivers.展开更多
Mobile phone(MP in the following) message is used routinely to communicate, yet the discourse analysis of it is relatively undeveloped. This new communication channel merits detailed discourse analysis, especially the...Mobile phone(MP in the following) message is used routinely to communicate, yet the discourse analysis of it is relatively undeveloped. This new communication channel merits detailed discourse analysis, especially the interaction differences among phone users. Using discourse analyze software Winmax2000 a to analyze the interaction code, this paper tries to shed light on the unique features of MP message communication and writing proficiency of English majors.展开更多
Research on human behavior has attracted increasing attention recently because of its scientific significance and potential applications.Some empirical results have indicated that the timing of many human activities f...Research on human behavior has attracted increasing attention recently because of its scientific significance and potential applications.Some empirical results have indicated that the timing of many human activities follows non-Poisson statistics.We analyze a real-life huge dataset of short message communication with 6326713 users and 37577781 records during the 2006 Chinese New Year.The results show that the number of short message sendings,the interevent time between two consecutive short message sendings and the response time all follow heavy-tailed distribution.We further observe a strongly positive correlation between the activity and the power-law exponent of the interevent time distribution.In addition,the short message communication system displays a bursty property yet no memory effects,which is in particular different from some well-studied human-activited systems such as email-sending,library-loaning and file printing.展开更多
Due to the openness of wireless multiuser networks,the private information transmitted in uplink or downlink is vulnerable to eavesdropping.Especially,when the downlink transmissions use nonorthogonal multiple access(...Due to the openness of wireless multiuser networks,the private information transmitted in uplink or downlink is vulnerable to eavesdropping.Especially,when the downlink transmissions use nonorthogonal multiple access(NOMA)techniques,the system further encounters interior eavesdropping.In order to address these security problems,we study the secret communication in multiuser networks with both uplink and downlink transmissions.Specifically,in uplink transmissions,the private messages transmitted in each slot are correlated,so any loss of the private information at the eavesdropper will prevent the eavesdropper from decoding the private information in later time slots.In downlink transmissions,the messages are correlated to the uplink information.In this way,any unexpected users who lose the expected user’s uplink information cannot decode its downlink information.The intercept probability is used to measure security performance and we analyze it in theory.Finally,simulation results are provided to corroborate our theoretical analysis.展开更多
Compressed sensing(CS)aims for seeking appropriate algorithms to recover a sparse vector from noisy linear observations.Currently,various Bayesian-based algorithms such as sparse Bayesian learning(SBL)and approximate ...Compressed sensing(CS)aims for seeking appropriate algorithms to recover a sparse vector from noisy linear observations.Currently,various Bayesian-based algorithms such as sparse Bayesian learning(SBL)and approximate message passing(AMP)based algorithms have been proposed.For SBL,it has accurate performance with robustness while its computational complexity is high due to matrix inversion.For AMP,its performance is guaranteed by the severe restriction of the measurement matrix,which limits its application in solving CS problem.To overcome the drawbacks of the above algorithms,in this paper,we present a low complexity algorithm for the single linear model that incorporates the vector AMP(VAMP)into the SBL structure with expectation maximization(EM).Specifically,we apply the variance auto-tuning into the VAMP to implement the E step in SBL,which decrease the iterations that require to converge compared with VAMP-EM algorithm when using a Gaussian mixture(GM)prior.Simulation results show that the proposed algorithm has better performance with high robustness under various cases of difficult measurement matrices.展开更多
Due to limited volume, weight and power consumption, micro-satellite has to reduce data transmission and storage capacity by image compression when performs earth observation missions. However, the quality of images m...Due to limited volume, weight and power consumption, micro-satellite has to reduce data transmission and storage capacity by image compression when performs earth observation missions. However, the quality of images may be unsatisfied. This paper considers the problem of recovering sparse signals by exploiting their unknown sparsity pattern. To model structured sparsity, the prior correlation of the support is encoded by imposing a transformed Gaussian process on the spike and slab probabilities. Then, an efficient approximate message-passing algorithm with structured spike and slab prior is derived for posterior inference, which, combined with a fast direct method, reduces the computational complexity significantly. Further, a unified scheme is developed to learn the hyperparameters using expectation maximization(EM) and Bethe free energy optimization. Simulation results on both synthetic and real data demonstrate the superiority of the proposed algorithm.展开更多
To overcome the limitations of conventional speech enhancement methods, such as inaccurate voice activity detector(VAD) and noise estimation, a novel speech enhancement algorithm based on the approximate message passi...To overcome the limitations of conventional speech enhancement methods, such as inaccurate voice activity detector(VAD) and noise estimation, a novel speech enhancement algorithm based on the approximate message passing(AMP) is adopted. AMP exploits the difference between speech and noise sparsity to remove or mute the noise from the corrupted speech. The AMP algorithm is adopted to reconstruct the clean speech efficiently for speech enhancement. More specifically, the prior probability distribution of speech sparsity coefficient is characterized by Gaussian-model, and the hyper-parameters of the prior model are excellently learned by expectation maximization(EM) algorithm. We utilize the k-nearest neighbor(k-NN) algorithm to learn the sparsity with the fact that the speech coefficients between adjacent frames are correlated. In addition, computational simulations are used to validate the proposed algorithm, which achieves better speech enhancement performance than other four baseline methods-Wiener filtering, subspace pursuit(SP), distributed sparsity adaptive matching pursuit(DSAMP), and expectation-maximization Gaussian-model approximate message passing(EM-GAMP) under different compression ratios and a wide range of signal to noise ratios(SNRs).展开更多
Mobile phone is regarded as"the fifth media"after newspaper,radio,TV and the Internet.The mobile phone short message further highlights the importance of written signs in communication".The thumb revolu...Mobile phone is regarded as"the fifth media"after newspaper,radio,TV and the Internet.The mobile phone short message further highlights the importance of written signs in communication".The thumb revolution"is eagerly anticipating one kind of trend by the hand replace of mouth,sound substitute for the quiet around us.My paper will analyze the language features and the culture features of mobile phone short messages which are written in Chinese and English.展开更多
To solve the key escrow problem of the identity-based cryptosystem, Girault introduced the notion of a self-certified public key, which not only eliminates the need to authenticate a public key but also solves the key...To solve the key escrow problem of the identity-based cryptosystem, Girault introduced the notion of a self-certified public key, which not only eliminates the need to authenticate a public key but also solves the key escrow problerrL This paper proposes a Self-Certified Signature （SCS） scheme with message recovery and two variants without using bilinear pairings： one is the authenticated encryption scheme in which only the designated re- ceiver can verify the signature, and the other is the authenticated encryption scheme with message linkage that deals with large messages. These three SCS schemes are provably secure in the random oracle model and are more efficient than previous schemes .展开更多
A novel mixed polling system with multiple stations is considered. Each station produces two classes of messages served with different disciplines. The real time message served with exhaustive service discipline and t...A novel mixed polling system with multiple stations is considered. Each station produces two classes of messages served with different disciplines. The real time message served with exhaustive service discipline and the unreal time message served with gated service discipline. Using an iterative method, the exact mean waiting times for both message classes are derived. The influence of the gate location of the message class served by the gated service discipline on the mean waiting time is also analyzed. The analytical results are verified with simulation method and agree well with simulation results.展开更多
This paper proposes a scheme for secure authentication of classical messages with single photons and a hashed function. The security analysis of this scheme is also given, which shows that anyone cannot forge valid me...This paper proposes a scheme for secure authentication of classical messages with single photons and a hashed function. The security analysis of this scheme is also given, which shows that anyone cannot forge valid message authentication codes （MACs）. In addition, the lengths of the authentication key and the MACs are invariable and shorter, in comparison with those presented authentication schemes. Moreover, quantum data storage and entanglement are not required in this scheme. Therefore, this scheme is more efficient and economical.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos.72171136 and 72134004)Humanities and Social Science Research Project,Ministry of Education of China(Grant No.21YJC630157)+1 种基金the Natural Science Foundation of Shandong Province(Grant No.ZR2022MG008)Shandong Provincial Colleges and Universities Youth Innovation Technology of China(Grant No.2022RW066)。
文摘Health information spreads rapidly,which can effectively control epidemics.However,the swift dissemination of information also has potential negative impacts,which increasingly attracts attention.Message fatigue refers to the psychological response characterized by feelings of boredom and anxiety that occur after receiving an excessive amount of similar information.This phenomenon can alter individual behaviors related to epidemic prevention.Additionally,recent studies indicate that pairwise interactions alone are insufficient to describe complex social transmission processes,and higher-order structures representing group interactions are crucial.To address this,we develop a novel epidemic model that investigates the interactions between information,behavioral responses,and epidemics.Our model incorporates the impact of message fatigue on the entire transmission system.The information layer is modeled using a static simplicial network to capture group interactions,while the disease layer uses a time-varying network based on activity-driven model with attractiveness to represent the self-protection behaviors of susceptible individuals and self-isolation behaviors of infected individuals.We theoretically describe the co-evolution equations using the microscopic Markov chain approach(MMCA)and get the epidemic threshold.Experimental results show that while the negative impact of message fatigue on epidemic transmission is limited,it significantly weakens the group interactions depicted by higher-order structures.Individual behavioral responses strongly inhibit the epidemic.Our simulations using the Monte Carlo(MC)method demonstrate that greater intensity in these responses leads to clustering of susceptible individuals in the disease layer.Finally,we apply the proposed model to real networks to verify its reliability.In summary,our research results enhance the understanding of the information-epidemic coupling dynamics,and we expect to provide valuable guidance for managing future emerging epidemics.
基金supported in part by the National Key R&D Program of China(No.2022YFB3904503)National Natural Science Foundation of China(No.62172418)the joint funds of National Natural Science Foundation of China and Civil Aviation Administration of China(No.U2133203).
文摘Due to the lack of authentication mechanism in BeiDou navigation satellite system(BDS),BD-Ⅱ civil navigation message(BDⅡ-CNAV) are vulnerable to spoofing attack and replay attack.To solve this problem,we present a security authentication protocol,called as BDSec,which is designed by using China’s cryptography Shangyong Mima(SM) series algorithms,such as SM2/4/9 and Zu Chongzhi(ZUC)algorithm.In BDSec protocol,both of BDⅡ-CNAV and signature information are encrypted using the SM4 algorithm(Symmetric encryption mechanism).The encrypted result is used as the subject authentication information.BDSec protocol applies SM9 algorithm(Identity-based cryptography mechanism) to protect the integrity of the BDⅡ-CNAV,adopts the SM2 algorithm(Public key cryptosystem) to guarantee the confidentiality of the important session information,and uses the ZUC algorithm(Encryption and integrity algorithm) to verify the integrity of the message authentication serial number and initial information and the information in authentication initialization sub-protocol respectively.The results of the SVO logic reasoning and performance analysis show that BDSec protocol meets security requirements for the dual user identity authentication in BDS and can realize the security authentication of BDⅡ-CNAV.
基金supported in part by the National Key R&D Program of China(No.2022YFB3904503)National Natural Science Foundation of China(No.62172418)。
文摘The BeiDou-Ⅱcivil navigation message(BDⅡ-CNAV)is transmitted in an open environment and no information integrity protection measures are provided.Hence,the BDⅡ-CNAV faces the threat of spoofing attacks,which can lead to wrong location reports and time indication.In order to deal with this threat,we proposed a scheme of anti-spoofing for BDⅡ-CNAV based on integrated information authentication.This scheme generates two type authentication information,one is authentication code information(ACI),which is applied to confirm the authenticity and reliability of satellite time information,and the other is signature information,which is used to authenticate the integrity of satellite location information and other information.Both authentication information is designed to embed into the reserved bits in BDⅡ-CNAV without changing the frame structure.In order to avoid authentication failure caused by public key error or key error,the key or public key prompt information(KPKPI)are designed to remind the receiver to update both keys in time.Experimental results indicate that the scheme can successfully detect spoofing attacks,and the authentication delay is less than 1%of the transmission delay,which meets the requirements of BDⅡ-CNAV information authentication.
文摘Hybrid precoder design is a key technique providing better antenna gain and reduced hardware complexity in millimeter-wave(mmWave)massive multiple-input multiple-output(MIMO)systems.In this paper,Gaussian Mixture learned approximate message passing(GM-LAMP)network is presented for the design of optimal hybrid precoders suitable for mmWave Massive MIMO systems.Optimal hybrid precoder designs using a compressive sensing scheme such as orthogonal matching pursuit(OMP)and its derivatives results in high computational complexity when the dimensionality of the sparse signal is high.This drawback can be addressed using classical iterative algorithms such as approximate message passing(AMP),which has comparatively low computational complexity.The drawbacks of AMP algorithm are fixed shrinkage parameter and non-consideration of prior distribution of the hybrid precoders.In this paper,the fixed shrinkage parameter problem of the AMP algorithm is addressed using learned AMP(LAMP)network,and is further enhanced as GMLAMP network using the concept of Gaussian Mixture distribution of the hybrid precoders.The simula-tion results show that the proposed GM-LAMP network achieves optimal hybrid precoder design with enhanced achievable rates,better accuracy and low computational complexity compared to the existing algorithms.
基金supported by the National Key Laboratory of Wireless Communications Foundation,China (IFN20230204)。
文摘This paper investigates the fundamental data detection problem with burst interference in massive multiple-input multiple-output orthogonal frequency division multiplexing(MIMO-OFDM) systems. In particular, burst interference may occur only on data symbols but not on pilot symbols, which means that interference information cannot be premeasured. To cancel the burst interference, we first revisit the uplink multi-user system and develop a matrixform system model, where the covariance pattern and the low-rank property of the interference matrix is discussed. Then, we propose a turbo message passing based burst interference cancellation(TMP-BIC) algorithm to solve the data detection problem, where the constellation information of target data is fully exploited to refine its estimate. Furthermore, in the TMP-BIC algorithm, we design one module to cope with the interference matrix by exploiting its lowrank property. Numerical results demonstrate that the proposed algorithm can effectively mitigate the adverse effects of burst interference and approach the interference-free bound.
基金supported in part by the Joint Foundation of National Natural Science Committee of China and Civil Aviation Administration of China under Grant U1933108in part by the Scientific Research Project of Tianjin Municipal Education Commission under Grant 2019KJ117.
文摘Due to the civil BeiDou navigation system is open,unauthenticated,and non-encrypted,civilian BeiDou navigation signals may have great security loopholes during transmission or reception.The main security loophole here is spoofing attacks.Spoofing attacks make the positioning or timing results of BeiDou civilian receivers wrong.Such errors may cause a series of security problems,which lays a serious hidden danger for Bei-Dou satellite information security.This article proposes an anti-spoofing method for BeiDou navigation system based on the combination of SM commercial cryptographic algorithm and Timed Efficient Stream Loss-tolerant Authentication(TESLA)for spoofing attacks.In this solution,we use the SM3 algorithm to generate a TESLA key chain with time information,and then use the key in the key chain to generate the message authentication code for the BeiDou D2 navigation message.The message authentication code is inserted into a reserved bit of the D2 navigation message.In addition,this solution uses the SM2 algorithm to protect and encrypt time information in the TESLA key chain to prevent key replay attacks in TESLA.The experimental results tested on the experimental platform built in this paper show that this scheme reduces the possibility of the BeiDou navigation system being deceived and enhances the safety of the BeiDou navigation system.
基金supported by the National Natural Science Foundation of Chi⁃na(61901417,U1804152,61801434)Science and Technology Re⁃search Project of Henan Province(212102210556,212102210566,212400410179).
文摘The orthogonal time frequency space(OTFS)modulation has emerged as a promis⁃ing modulation scheme for wireless communications in high-mobility scenarios.An efficient detector is of paramount importance to harvesting the time and frequency diversities promised by OTFS.Recently,some message passing based detectors have been developed by exploiting the features of the OTFS channel matrices.In this paper,we provide an overview of some re⁃cent message passing based OTFS detectors,compare their performance,and shed some light on potential research on the design of message passing based OTFS receivers.
文摘Mobile phone(MP in the following) message is used routinely to communicate, yet the discourse analysis of it is relatively undeveloped. This new communication channel merits detailed discourse analysis, especially the interaction differences among phone users. Using discourse analyze software Winmax2000 a to analyze the interaction code, this paper tries to shed light on the unique features of MP message communication and writing proficiency of English majors.
基金by the National Natural Science Foundation of China under Grant Nos 90924011,60973069,10975126,70971089 and 70871082the China Postdoctoral Science Foundation under Grant No 201003694the Sichuan Provincial Science and Technology Department under Grant No 2010HH0002.
文摘Research on human behavior has attracted increasing attention recently because of its scientific significance and potential applications.Some empirical results have indicated that the timing of many human activities follows non-Poisson statistics.We analyze a real-life huge dataset of short message communication with 6326713 users and 37577781 records during the 2006 Chinese New Year.The results show that the number of short message sendings,the interevent time between two consecutive short message sendings and the response time all follow heavy-tailed distribution.We further observe a strongly positive correlation between the activity and the power-law exponent of the interevent time distribution.In addition,the short message communication system displays a bursty property yet no memory effects,which is in particular different from some well-studied human-activited systems such as email-sending,library-loaning and file printing.
基金supported in part by the Fundamental Research Funds for the Central Universities(No.21620350)in part by the National Natural Science Foundation of China(No.62102167 and No.62032025)in part by the Guangdong Basic and Applied Basic Research Foundation(2020A1515110364).
文摘Due to the openness of wireless multiuser networks,the private information transmitted in uplink or downlink is vulnerable to eavesdropping.Especially,when the downlink transmissions use nonorthogonal multiple access(NOMA)techniques,the system further encounters interior eavesdropping.In order to address these security problems,we study the secret communication in multiuser networks with both uplink and downlink transmissions.Specifically,in uplink transmissions,the private messages transmitted in each slot are correlated,so any loss of the private information at the eavesdropper will prevent the eavesdropper from decoding the private information in later time slots.In downlink transmissions,the messages are correlated to the uplink information.In this way,any unexpected users who lose the expected user’s uplink information cannot decode its downlink information.The intercept probability is used to measure security performance and we analyze it in theory.Finally,simulation results are provided to corroborate our theoretical analysis.
基金supported by NSFC projects(61960206005,61803211,61871111,62101275,62171127,61971136,and 62001056)Jiangsu NSF project(BK20200820)+1 种基金Postgraduate Research&Practice Innovation Program of Jiangsu Province(KYCX210106)Research Fund of National Mobile Communications Research Laboratory.
文摘Compressed sensing(CS)aims for seeking appropriate algorithms to recover a sparse vector from noisy linear observations.Currently,various Bayesian-based algorithms such as sparse Bayesian learning(SBL)and approximate message passing(AMP)based algorithms have been proposed.For SBL,it has accurate performance with robustness while its computational complexity is high due to matrix inversion.For AMP,its performance is guaranteed by the severe restriction of the measurement matrix,which limits its application in solving CS problem.To overcome the drawbacks of the above algorithms,in this paper,we present a low complexity algorithm for the single linear model that incorporates the vector AMP(VAMP)into the SBL structure with expectation maximization(EM).Specifically,we apply the variance auto-tuning into the VAMP to implement the E step in SBL,which decrease the iterations that require to converge compared with VAMP-EM algorithm when using a Gaussian mixture(GM)prior.Simulation results show that the proposed algorithm has better performance with high robustness under various cases of difficult measurement matrices.
基金partially supported by the National Nature Science Foundation of China(Grant No.91438206 and 91638205)supported by Zhejiang Province Natural Science Foundation of China(Grant No.LQ18F010001)
文摘Due to limited volume, weight and power consumption, micro-satellite has to reduce data transmission and storage capacity by image compression when performs earth observation missions. However, the quality of images may be unsatisfied. This paper considers the problem of recovering sparse signals by exploiting their unknown sparsity pattern. To model structured sparsity, the prior correlation of the support is encoded by imposing a transformed Gaussian process on the spike and slab probabilities. Then, an efficient approximate message-passing algorithm with structured spike and slab prior is derived for posterior inference, which, combined with a fast direct method, reduces the computational complexity significantly. Further, a unified scheme is developed to learn the hyperparameters using expectation maximization(EM) and Bethe free energy optimization. Simulation results on both synthetic and real data demonstrate the superiority of the proposed algorithm.
基金supported by National Natural Science Foundation of China(NSFC)(No.61671075)Major Program of National Natural Science Foundation of China(No.61631003)。
文摘To overcome the limitations of conventional speech enhancement methods, such as inaccurate voice activity detector(VAD) and noise estimation, a novel speech enhancement algorithm based on the approximate message passing(AMP) is adopted. AMP exploits the difference between speech and noise sparsity to remove or mute the noise from the corrupted speech. The AMP algorithm is adopted to reconstruct the clean speech efficiently for speech enhancement. More specifically, the prior probability distribution of speech sparsity coefficient is characterized by Gaussian-model, and the hyper-parameters of the prior model are excellently learned by expectation maximization(EM) algorithm. We utilize the k-nearest neighbor(k-NN) algorithm to learn the sparsity with the fact that the speech coefficients between adjacent frames are correlated. In addition, computational simulations are used to validate the proposed algorithm, which achieves better speech enhancement performance than other four baseline methods-Wiener filtering, subspace pursuit(SP), distributed sparsity adaptive matching pursuit(DSAMP), and expectation-maximization Gaussian-model approximate message passing(EM-GAMP) under different compression ratios and a wide range of signal to noise ratios(SNRs).
文摘Mobile phone is regarded as"the fifth media"after newspaper,radio,TV and the Internet.The mobile phone short message further highlights the importance of written signs in communication".The thumb revolution"is eagerly anticipating one kind of trend by the hand replace of mouth,sound substitute for the quiet around us.My paper will analyze the language features and the culture features of mobile phone short messages which are written in Chinese and English.
基金This research was supported partially by the National Natural Science Foundation of China under Grants No. 61103247, No. 6110209 the Natural Science Foundation of Fujian Province under Grant No. 2011J05147+1 种基金 the Research Foundation of Education Bureau of Fujian Province under Grant No. JBll017 the Foundation for Excellent Young Teachers of Fujian Normal University under Grant No. fjsdjk2012049.
文摘To solve the key escrow problem of the identity-based cryptosystem, Girault introduced the notion of a self-certified public key, which not only eliminates the need to authenticate a public key but also solves the key escrow problerrL This paper proposes a Self-Certified Signature （SCS） scheme with message recovery and two variants without using bilinear pairings： one is the authenticated encryption scheme in which only the designated re- ceiver can verify the signature, and the other is the authenticated encryption scheme with message linkage that deals with large messages. These three SCS schemes are provably secure in the random oracle model and are more efficient than previous schemes .
基金Sponsored by the National Natural Science Foundation of China (No .60474031) the National"863"Program Project (2002AA412010-08)
文摘A novel mixed polling system with multiple stations is considered. Each station produces two classes of messages served with different disciplines. The real time message served with exhaustive service discipline and the unreal time message served with gated service discipline. Using an iterative method, the exact mean waiting times for both message classes are derived. The influence of the gate location of the message class served by the gated service discipline on the mean waiting time is also analyzed. The analytical results are verified with simulation method and agree well with simulation results.
基金supported by the National Natural Science Foundation of China (Grant Nos 60873191 and 60821001)the Specialized Research Fund for the Doctoral Program of Higher Education (Grant No 200800131016)+5 种基金Beijing Nova Program (Grant No2008B51)Key Project of the Chinese Ministry of Education (Grant No 109014)the Natural Science Foundation of Beijing (Grant No 4072020)the National Laboratory for Modern Communications Science Foundation of China (Grant No 9140C1101010601)the Natural Science Foundation of Education Bureau of Henan Province (Grant No 2008B120005)the Youth Foundation of Luoyang Normal University
文摘This paper proposes a scheme for secure authentication of classical messages with single photons and a hashed function. The security analysis of this scheme is also given, which shows that anyone cannot forge valid message authentication codes （MACs）. In addition, the lengths of the authentication key and the MACs are invariable and shorter, in comparison with those presented authentication schemes. Moreover, quantum data storage and entanglement are not required in this scheme. Therefore, this scheme is more efficient and economical.
