The human brain is a complex intelligent system composed of tens of billions of neurons interconnected through synapses,and its intricate network structure has consistently attracted numerous scientists to explore the...The human brain is a complex intelligent system composed of tens of billions of neurons interconnected through synapses,and its intricate network structure has consistently attracted numerous scientists to explore the mysteries of brain functions.However,most existing studies have only verified the biological mimicry characteristics of memristors at the single neuron-synapse level,and there is still a lack of research on memristors simulating synaptic coupling between neurons in multi-neuron networks.Based on this,this paper uses discrete memristors to couple dual discrete Rulkov neurons,and adds synaptic crosstalk between the two discrete memristors to form a neuronal network.A memristor-coupled dual-neuron map,called the Rulkov-memristor-Rulkov(R-M-R)map,is constructed to simulate synaptic connections between neurons in biological tissues.Then,the equilibrium points of the R-M-R map are studied.Subsequently,the effect of parameter variations on the dynamic performance of the R-M-R map is comprehensively analyzed using bifurcation diagram,phase diagram,Lyapunov exponent spectrum(LEs),firing diagram,and spectral entropy(SE)complexity algorithms.In the RM-R map,diverse categories of periodic,chaotic,and hyperchaotic attractors,as well as different states of firing patterns,can be observed.Additionally,different types of state transitions and coexisting attractors are discovered.Finally,the feasibility of the model in digital circuits is verified using a DSP hardware platform.In this study,the coupling principle of biological neurons is simulated,the chaotic dynamic behavior of the R-M-R map is analyzed,and a foundation is laid for deciphering the complex working mechanisms of the brain.展开更多
To further improve the secrecy rate,a joint optimization scheme for the reconfigurable intelligent surface(RIS)phase shift and the power allocation is proposed in the untrusted relay(UR)networks assisted by the RIS.Th...To further improve the secrecy rate,a joint optimization scheme for the reconfigurable intelligent surface(RIS)phase shift and the power allocation is proposed in the untrusted relay(UR)networks assisted by the RIS.The eavesdropping on the UR is interfered by a source-based jamming strategy.Under the constraints of unit modulus and total power,the RIS phase shift,the power allocation between the confidential signal and the jamming signal,and the power allocation between the source node and the UR are jointly optimized to maximize the secrecy rate.The complex multivariable coupling problem is decomposed into three sub-problems,and the non-convexity of the objective function and the constraints is solved with semi-definite relaxation.Simulation results indicate that the secrecy rate is remarkably enhanced with the proposed scheme compared with the equal power allocation scheme,the random phase shift scheme,and the no-RIS scheme.展开更多
For digital image transmission security and information copyright,a new holographic image self-embedding watermarking encryption scheme is proposed.Firstly,the plaintext is converted to the RGB three-color channel,the...For digital image transmission security and information copyright,a new holographic image self-embedding watermarking encryption scheme is proposed.Firstly,the plaintext is converted to the RGB three-color channel,the corresponding phase hologram is obtained by holographic technology and the watermark is self-embedded in the frequency domain.Secondly,by applying the Hilbert transform principle and genetic center law,a complete set of image encryption algorithms is constructed to realize the encryption of image information.Finally,simulation results and security analysis indicate that the scheme can effectively encrypt and decrypt image information and realize the copyright protection of information.The introduced scheme can provide some support for relevant theoretical research,and has practical significance.展开更多
his special issue is dedicated to security problems in wireless and quan-turn communications. Papers for this issue were invited, and after peer review, eight were selected for publication. The first part of this issu...his special issue is dedicated to security problems in wireless and quan-turn communications. Papers for this issue were invited, and after peer review, eight were selected for publication. The first part of this issue comprises four papers on recent advances in physical layer security forwireless networks. The second Part comprises another four papers on quantum com- munications.展开更多
In optical computing systems for image tasks,optical signals of image data are usually generated by signal modulators,whose speed limits computational performance.To address this,a framework of image memory that can p...In optical computing systems for image tasks,optical signals of image data are usually generated by signal modulators,whose speed limits computational performance.To address this,a framework of image memory that can permanently store the image and instantaneously generate its corresponding optical signals has been proposed.In this framework,an original image is sliced into non-overlapping sub-images,each of which contains 3 pixel×3 pixel or 5 pixel×5 pixel,and these subimages are respectively stored in storage units,which are nine-channel or 25-channel power splitters(PSs).The gray values of pixels in each sub-image are sequentially mapped to the light intensity of channels in each PS.These PSs are inversely designed by combining the adjoint method(AM)and the finite-difference frequency-domain method.Using this method,high-performance memory has been realized based on PSs,with a maximum 33.37 dB signal-to-noise ratio.Using multiobjective AM,the storage capacity has been doubled according to the working wavelengths.For example,two sub-images with pixels arranged as‘T'and‘L'shapes can be retrieved at 1310 and 1550 nm,respectively.This framework provides highly stable,non-volatile image storage,and instantaneous generation of optical signals for future all-optical computing systems.展开更多
We theoretically investigate the optical second-order sideband generation(OSSG)in an optical parity-time(PT)symmetric system,which consists of a passive cavity trapping the atomic ensemble and an active cavity.Compare...We theoretically investigate the optical second-order sideband generation(OSSG)in an optical parity-time(PT)symmetric system,which consists of a passive cavity trapping the atomic ensemble and an active cavity.Compared with the double-passive system,it is found that near the exceptional point(EP),the efficiency of the OSSG increases sharply not only for the blue probepump detuning resonant case but also for the red one.Using experimentally achievable parameters,we study the effect of the atomic ensemble on the efficiency of the OSSG in the PT-symmetric system.The numerical results show that the efficiency of the OSSG is 30%higher than that of the first-order sideband,which is realized easily by simultaneously modulating the atom-cavity coupling strength and detuning.Moreover,the efficiency of the OSSG can also be tuned effectively by the pump power,and the efficiency is robust when the pump power is strong enough.This study may have some guidance for modulating the nonlinear optical properties and controlling light propagation,which may stimulate further applications in optical communications.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.62571079)the Technological Innovation Projects in the Field of Artificial Intelligence in Liaoning Province(Grant No.2023JH26/10300011)+1 种基金the Basic Scientific Research Projects in the Department of Education of Liaoning Province(Grant No.LJ212410152049)the Liaoning Provincial Science and Technology Plan Joint Project(Grant No.2025-BSLH-041)。
文摘The human brain is a complex intelligent system composed of tens of billions of neurons interconnected through synapses,and its intricate network structure has consistently attracted numerous scientists to explore the mysteries of brain functions.However,most existing studies have only verified the biological mimicry characteristics of memristors at the single neuron-synapse level,and there is still a lack of research on memristors simulating synaptic coupling between neurons in multi-neuron networks.Based on this,this paper uses discrete memristors to couple dual discrete Rulkov neurons,and adds synaptic crosstalk between the two discrete memristors to form a neuronal network.A memristor-coupled dual-neuron map,called the Rulkov-memristor-Rulkov(R-M-R)map,is constructed to simulate synaptic connections between neurons in biological tissues.Then,the equilibrium points of the R-M-R map are studied.Subsequently,the effect of parameter variations on the dynamic performance of the R-M-R map is comprehensively analyzed using bifurcation diagram,phase diagram,Lyapunov exponent spectrum(LEs),firing diagram,and spectral entropy(SE)complexity algorithms.In the RM-R map,diverse categories of periodic,chaotic,and hyperchaotic attractors,as well as different states of firing patterns,can be observed.Additionally,different types of state transitions and coexisting attractors are discovered.Finally,the feasibility of the model in digital circuits is verified using a DSP hardware platform.In this study,the coupling principle of biological neurons is simulated,the chaotic dynamic behavior of the R-M-R map is analyzed,and a foundation is laid for deciphering the complex working mechanisms of the brain.
基金supported by the National Natural Science Foundation of China(Grant No.61961024)the Top Double 1000 Talent Programme of Jiangxi Province(Grant No.JXSQ2019201055)+1 种基金the Natural Science Foundation of Jiangxi Province(Grant No.20181BAB202001)the Opening Project of Shanghai Key Laboratory of Integrated Administration Technologies for Information Security(Grant No.AGK201602)。
文摘To further improve the secrecy rate,a joint optimization scheme for the reconfigurable intelligent surface(RIS)phase shift and the power allocation is proposed in the untrusted relay(UR)networks assisted by the RIS.The eavesdropping on the UR is interfered by a source-based jamming strategy.Under the constraints of unit modulus and total power,the RIS phase shift,the power allocation between the confidential signal and the jamming signal,and the power allocation between the source node and the UR are jointly optimized to maximize the secrecy rate.The complex multivariable coupling problem is decomposed into three sub-problems,and the non-convexity of the objective function and the constraints is solved with semi-definite relaxation.Simulation results indicate that the secrecy rate is remarkably enhanced with the proposed scheme compared with the equal power allocation scheme,the random phase shift scheme,and the no-RIS scheme.
基金Project supported by the National Natural Science Foundation of China(Grant No.62061014)。
文摘For digital image transmission security and information copyright,a new holographic image self-embedding watermarking encryption scheme is proposed.Firstly,the plaintext is converted to the RGB three-color channel,the corresponding phase hologram is obtained by holographic technology and the watermark is self-embedded in the frequency domain.Secondly,by applying the Hilbert transform principle and genetic center law,a complete set of image encryption algorithms is constructed to realize the encryption of image information.Finally,simulation results and security analysis indicate that the scheme can effectively encrypt and decrypt image information and realize the copyright protection of information.The introduced scheme can provide some support for relevant theoretical research,and has practical significance.
文摘his special issue is dedicated to security problems in wireless and quan-turn communications. Papers for this issue were invited, and after peer review, eight were selected for publication. The first part of this issue comprises four papers on recent advances in physical layer security forwireless networks. The second Part comprises another four papers on quantum com- munications.
基金supported by the National Natural Science Foundation of China(No.62161025)the High-level Talent Introduction Research Program of Shanghai University of Engineering Science(No.2023RC-GC09)the High-Level Local University Construction Innovative Talents Training Program of Shanghai University of Engineering Science(No.25XAI008)。
文摘In optical computing systems for image tasks,optical signals of image data are usually generated by signal modulators,whose speed limits computational performance.To address this,a framework of image memory that can permanently store the image and instantaneously generate its corresponding optical signals has been proposed.In this framework,an original image is sliced into non-overlapping sub-images,each of which contains 3 pixel×3 pixel or 5 pixel×5 pixel,and these subimages are respectively stored in storage units,which are nine-channel or 25-channel power splitters(PSs).The gray values of pixels in each sub-image are sequentially mapped to the light intensity of channels in each PS.These PSs are inversely designed by combining the adjoint method(AM)and the finite-difference frequency-domain method.Using this method,high-performance memory has been realized based on PSs,with a maximum 33.37 dB signal-to-noise ratio.Using multiobjective AM,the storage capacity has been doubled according to the working wavelengths.For example,two sub-images with pixels arranged as‘T'and‘L'shapes can be retrieved at 1310 and 1550 nm,respectively.This framework provides highly stable,non-volatile image storage,and instantaneous generation of optical signals for future all-optical computing systems.
基金supported by the National Natural Science Foundation of China(Grant Nos.61368002,91736106,11674390,and 91836302)the Open Research Fund Program of the State Key Laboratory of Low-Dimensional Quantum Physics(Grant No.KF201711)+1 种基金the Foundation for Distinguished Young Scientists of Jiangxi Province(Grant No.20162BCB23009)the Graduate Innovation Special Fund of Jiangxi Province(Grant No.YC2019-S102)。
文摘We theoretically investigate the optical second-order sideband generation(OSSG)in an optical parity-time(PT)symmetric system,which consists of a passive cavity trapping the atomic ensemble and an active cavity.Compared with the double-passive system,it is found that near the exceptional point(EP),the efficiency of the OSSG increases sharply not only for the blue probepump detuning resonant case but also for the red one.Using experimentally achievable parameters,we study the effect of the atomic ensemble on the efficiency of the OSSG in the PT-symmetric system.The numerical results show that the efficiency of the OSSG is 30%higher than that of the first-order sideband,which is realized easily by simultaneously modulating the atom-cavity coupling strength and detuning.Moreover,the efficiency of the OSSG can also be tuned effectively by the pump power,and the efficiency is robust when the pump power is strong enough.This study may have some guidance for modulating the nonlinear optical properties and controlling light propagation,which may stimulate further applications in optical communications.
