In order to storage resource of a radar recognition system, schemes for reducing data storage and for correlation discrimination of radar based on wavelet packets were proposed Experiment results at various signal-t...In order to storage resource of a radar recognition system, schemes for reducing data storage and for correlation discrimination of radar based on wavelet packets were proposed Experiment results at various signal-to-noise ratios were given The given.ability of the reduced data method's validity are supported by experimental results. Using optimal basis can get higher successful recognition rate using rigid wavelet basis.展开更多
Kubernetes has become the dominant container orchestration platform,withwidespread adoption across industries.However,its default pod-to-pod communicationmechanism introduces security vulnerabilities,particularly IP s...Kubernetes has become the dominant container orchestration platform,withwidespread adoption across industries.However,its default pod-to-pod communicationmechanism introduces security vulnerabilities,particularly IP spoofing attacks.Attackers can exploit this weakness to impersonate legitimate pods,enabling unauthorized access,lateral movement,and large-scale Distributed Denial of Service(DDoS)attacks.Existing security mechanisms such as network policies and intrusion detection systems introduce latency and performance overhead,making them less effective in dynamic Kubernetes environments.This research presents PodCA,an eBPF-based security framework designed to detect and prevent IP spoofing in real time while minimizing performance impact.PodCA integrates with Kubernetes’Container Network Interface(CNI)and uses eBPF to monitor and validate packet metadata at the kernel level.It maintains a container network mapping table that tracks pod IP assignments,validates packet legitimacy before forwarding,and ensures network integrity.If an attack is detected,PodCA automatically blocks spoofed packets and,in cases of repeated attempts,terminates compromised pods to prevent further exploitation.Experimental evaluation on an AWS Kubernetes cluster demonstrates that PodCA detects and prevents spoofed packets with 100%accuracy.Additionally,resource consumption analysis reveals minimal overhead,with a CPU increase of only 2–3%per node and memory usage rising by 40–60 MB.These results highlight the effectiveness of eBPF in securing Kubernetes environments with low overhead,making it a scalable and efficient security solution for containerized applications.展开更多
Multi-electron and multi-orbital effects play a crucial role in the interaction of strong laser fields with complex molecules.Here,multi-electron effects encompass not only electron-electron Coulomb interactions and e...Multi-electron and multi-orbital effects play a crucial role in the interaction of strong laser fields with complex molecules.Here,multi-electron effects encompass not only electron-electron Coulomb interactions and exchangecorrelation effects but also the interference between the dynamics of different electron wave packets.展开更多
Software-defined satellite networks(SDSNs)play an essential role in future networks.Due to the diverse service scenarios,SDSN faces the demand of packet processing for heterogeneous protocols.Existing packet switching...Software-defined satellite networks(SDSNs)play an essential role in future networks.Due to the diverse service scenarios,SDSN faces the demand of packet processing for heterogeneous protocols.Existing packet switching typically works on one single protocol.For protocol-heterogeneous users,existing packet switch architectures have to construct multiple protocol-specific switching instances,resulting in severe resource waste.In this article,we propose the heterogeneous protocol-independent packet switch architecture(HISA).HISA employs a fast parsing structure to achieve efficient heterogeneous packet parsing and a novel match-action pipeline to achieve shared packet processing among heterogeneous users.HISA can also support the online configuration of switching behaviors.Use cases illustrate the effectiveness of applying HISA in SDSN.Numerical results show that compared to existing packet switching,HISA can significantly improve the resource utilization of SDSN.展开更多
High-quality services in today’s mobile networks require stable delivery of bandwidth-intensive network content.Multipath QUIC(MPQUIC),as a multipath protocol that extends QUIC,can utilize multiple paths to support s...High-quality services in today’s mobile networks require stable delivery of bandwidth-intensive network content.Multipath QUIC(MPQUIC),as a multipath protocol that extends QUIC,can utilize multiple paths to support stable and efficient transmission.The standard coupled congestion control algorithm in MPQUIC synchronizes these paths to manage congestion,meeting fairness requirements and improving transmission efficiency.However,current algorithms’Congestion Window(CWND)reduction approach significantly decreases CWND upon packet loss,which lowers effective throughput,regardless of the congestion origin.Furthermore,the uncoupled Slow-Start(SS)in MPQUIC leads to independent exponential CWND growth on each path,potentially causing buffer overflow.To address these issues,we propose the CC-OLIA,which incorporates Packet Loss Classifcation(PLC)and Coupled Slow-Start(CSS).The PLC distinguishes between congestion-induced and random packet losses,adjusting CWND reduction accordingly to maintain throughput.Concurrently,the CSS module coordinates CWND growth during the SS,preventing abrupt increases.Implementation on MININET shows that CC-OLIA not only maintains fair performance but also enhances transmission efficiency across diverse network conditions.展开更多
Pre-Authentication and Post-Connection(PAPC)plays a crucial role in realizing the Zero Trust security model by ensuring that access to network resources is granted only after successful authentication.While earlier ap...Pre-Authentication and Post-Connection(PAPC)plays a crucial role in realizing the Zero Trust security model by ensuring that access to network resources is granted only after successful authentication.While earlier approaches such as Port Knocking(PK)and Single Packet Authorization(SPA)introduced pre-authentication concepts,they suffer from limitations including plaintext communication,protocol dependency,reliance on dedicated clients,and inefficiency under modern network conditions.These constraints hinder their applicability in emerging distributed and resource-constrained environments such as AIoT and browser-based systems.To address these challenges,this study proposes a novel port-sequence-based PAPC scheme structured as a modular model comprising a client,server,and ephemeral Key Management System(KMS).The system employs the Advanced Encryption Standard(AES-128)to protect message confidentiality and uses a Hash-Based Message Authentication Code(HMAC-SHA256)to ensure integrity.Authentication messages are securely fragmented and mapped to destination port numbers using a signature-based avoidance algorithm,which prevents collisions with unsafe or reserved port ranges.The server observes incoming port sequences,retrieves the necessary keys from the KMS,reconstructs and verifies the encrypted data,and conditionally updates firewall policies.Unlike SPA,which requires decrypting all incoming payloads and imposes server-side overhead,the proposed system verifies only port-derived fragments,significantly reducing computational burden.Furthermore,it eliminates the need for raw socket access or custom clients,supporting browser-based operation and enabling protocol-independent deployment.Through a functional web-based prototype and emulated testing,the system achieved an F1-score exceeding 95%in detecting unauthorized access while maintaining low resource overhead.Although port sequence generation introduces some client-side cost,it remains lightweight and scalable.By tightly integrating lightweight cryptographic algorithms with a transport-layer communication model,this work presents a conceptually validated architecture that contributes a novel direction for interoperable and scalable Zero Trust enforcement in future network ecosystems.展开更多
The hydration state of amphiphilic block copolymers during the self-assembly transition is closely related to the structure and properties of copolymers. In this study, the temperature-induced self-assembly of copolym...The hydration state of amphiphilic block copolymers during the self-assembly transition is closely related to the structure and properties of copolymers. In this study, the temperature-induced self-assembly of copolymer poly(N,N-dimethylacrylamide)-poly(diacetone acrylamide)(PDMAA_(30)-PDAAM_(60))_(2)in aqueous solution was monitored by near-infrared spectroscopy with water as a probe. The wavelet packet transform was employed to improve the spectral resolution. The spectral information of hydrated water surrounding the hydrophilic PDMAA and hydrophobic PDAAM blocks was then extracted, revealing the significant roles of water in morphological transition of the copolymer from spherical to worm-like micelles. Specifically, water molecules interacting with N atoms and C=O groups of the hydrophilic block gradually decrease during the morphological transition, while hydrogen-bond structures NH–CO of the hydrophobic block gradually break, bringing more water molecules into contact with the hydrophobic block. This work provides a foundation for exploring the role of water molecules during the self-assembly transition of complex block copolymers.展开更多
Rotational dynamics simulations of neutral O_(2)molecules driven by linearly,elliptically and circularly polarized femtosecond pulsed lasers are carried out using a full quantum time-dependent wave packet evolution me...Rotational dynamics simulations of neutral O_(2)molecules driven by linearly,elliptically and circularly polarized femtosecond pulsed lasers are carried out using a full quantum time-dependent wave packet evolution method.Here,the direction of laser propagation is set along the z axis,and the polarization plane is restricted to the xy plane.The results indicate that the alignment of O_(2)molecules in the z direction is weakly affected by varying the ellipticity when the total laser intensity is held constant.For rotation within the xy plane,the linearly polarized laser significantly excites rotational motion,with the degree of excitation increasing as the ellipticity increases.In contrast,under the influence of a circularly polarized laser,the angular distribution of O_(2)molecules in the xy plane remains isotropic.Additionally,the effects of the initial rotational quantum number,the temperature of the O_(2)molecules and the nuclear spin on laser-induced alignment are discussed.展开更多
Reliable and efficient communication is essential for Unmanned Aerial Vehicle(UAV)networks,especially in dynamic and resource-constrained environments such as disaster management,surveillance,and environmental monitor...Reliable and efficient communication is essential for Unmanned Aerial Vehicle(UAV)networks,especially in dynamic and resource-constrained environments such as disaster management,surveillance,and environmental monitoring.Frequent topology changes,high mobility,and limited energy availability pose significant challenges to maintaining stable and high-performance routing.Traditional routing protocols,such as Ad hoc On-Demand Distance Vector(AODV),Load-Balanced Optimized Predictive Ad hoc Routing(LB-OPAR),and Destination-Sequenced Distance Vector(DSDV),often experience performance degradation under such conditions.To address these limitations,this study evaluates the effectiveness of Dynamic Adaptive Routing(DAR),a protocol designed to adapt routing decisions in real time based on network dynamics and resource constraints.The research utilizes the Network Simulator 3(NS-3)platform to conduct controlled simulations,measuring key performance indicators such as latency,Packet Delivery Ratio(PDR),energy consumption,and throughput.Comparative analysis reveals that DAR consistently outperforms conventional protocols,achieving a 20%-30% reduction in latency,a 25% decrease in energy consumption,and marked improvements in throughput and PDR.These results highlight DAR’s ability to maintain high communication reliability while optimizing resource usage in challenging operational scenarios.By providing empirical evidence of DAR’s advantages in highly dynamic UAV network environments,this study contributes to advancing adaptive routing strategies.The findings not only validate DAR’s robustness and scalability but also lay the groundwork for integrating artificial intelligence-driven decision-making and real-world UAV deployment.Future work will explore cross-layer optimization,multi-UAV coordination,and experimental validation in field trials,aiming to further enhance communication resilience and energy efficiency in next-generation aerial networks.展开更多
We investigate the diffractive paraxial wave equation with an external potential,utilizing self-similarity and variable separation methods.The exact solution to this evolution equation,expressed through Scorer functio...We investigate the diffractive paraxial wave equation with an external potential,utilizing self-similarity and variable separation methods.The exact solution to this evolution equation,expressed through Scorer functions,gives rise to the new Scorer beams.We explore the dynamics of counterpropagating Scorer beams,as promising optical wave packets,focusing on their compression behavior.The Scorer beams are characterized by two key parameters:the attenuation factor and the initial pulse width.By appropriately adjusting these parameters,significant beam compression can be achieved.Specifically,increasing the attenuation factor enhances compression and raises pulse amplitude,while reducing the initial pulse width further amplifies these effects.Along the way,we observe interesting interference patterns of the counterpropagating Scorer beams that have never been seen before.This study introduces a novel approach to beam compression and opens new possibilities for practical applications of Scorer beams.展开更多
We present a graphics processing units(GPU)parallelization based three-dimensional time-dependent Schrödinger equation(3D-TDSE)code to simulate the interaction between single-active-electron atom/molecule and arb...We present a graphics processing units(GPU)parallelization based three-dimensional time-dependent Schrödinger equation(3D-TDSE)code to simulate the interaction between single-active-electron atom/molecule and arbitrary types of laser pulses with either velocity gauge or length gauge in Cartesian coordinates.Split-operator method combined with fast Fourier transforms(FFT)is used to perform the time evolution.Sample applications in different scenarios,such as stationary state energies,photon ionization spectra,attosecond clocks,and high-order harmonic generation(HHG),are given for the hydrogen atom.Repeatable results can be obtained with the benchmark program PCTDSE,which is a 3DTDSE Fortran solver parallelized using message passing interface(MPI)library.With the help of GPU acceleration and vectorization strategy,our code running on a single NVIDIA 3090 RTX GPU can achieve about 10 times faster computation speed than PCTDSE running on a 144 Intel Xeon CPU cores server with the same accuracy.In addition,3D-GTDSE can also be modified slightly to simulate non-adiabatic dynamics involving the coupling of nuclear and electronic wave packets,as well as pure nuclear wave packet dynamics in the presence of strong laser fields within 3 dimensions.Additionally,we have also discussed the limitations and shortcomings of our code in utilizing GPU memory.The 3D-GTDSE code provides an alternative tool for studying the ultrafast nonlinear dynamics under strong laser fields.展开更多
Based on the massive data collected with a passive network monitoring equipment placed in China＇s backbone, we present a deep insight into the network backbone traffic and evaluate various ways for inproving traffic ...Based on the massive data collected with a passive network monitoring equipment placed in China＇s backbone, we present a deep insight into the network backbone traffic and evaluate various ways for inproving traffic classifying efficiency in this pa- per. In particular, the study has scrutinized the net- work traffic in terms of protocol types and signatures, flow length, and port distffoution, from which mean- ingful and interesting insights on the current Intemet of China from the perspective of both the packet and flow levels are derived. We show that the classifica- tion efficiency can be greatly irrproved by using the information of preferred ports of the network applica- tions. Quantitatively, we find two traffic duration thresholds, with which 40% of TCP flows and 70% of UDP flows can be excluded from classification pro- cessing while the in^act on classification accuracy is trivial, i.e., the classification accuracy can still reach a high level by saving 85% of the resources.展开更多
The propagation of wave packets and its relationship with the subtropical jet was investigated for the period 26 29 January 2008 over southern China using ECMWF Interim re-analysis data. Wave packets propagated from t...The propagation of wave packets and its relationship with the subtropical jet was investigated for the period 26 29 January 2008 over southern China using ECMWF Interim re-analysis data. Wave packets propagated from the north to the south side of an upper front with eastward development along the upper front during this period. Due to the eastward development of propagation, the acceleration of geostrophic westerly winds shifted eastward along the front. There were two primary sources of the propagation of wave packets at around 30°N. The first was the temperature inversion layer below 500 hPa, and the second was baroclinic zones located along the polarward flank of the subtropical jet in the middle and upper troposphere. Most wave packets propagated horizontally from the baroclinic zones and then converged on the zero meridional gradients of zonal winds.展开更多
文摘In order to storage resource of a radar recognition system, schemes for reducing data storage and for correlation discrimination of radar based on wavelet packets were proposed Experiment results at various signal-to-noise ratios were given The given.ability of the reduced data method's validity are supported by experimental results. Using optimal basis can get higher successful recognition rate using rigid wavelet basis.
基金partially supported by Asia Pacific University of Technology&Innovation(APU)Bukit Jalil,Kuala Lumpur,MalaysiaThe funding body had no role in the study design,data collection,analysis,interpretation,or writing of the manuscript.
文摘Kubernetes has become the dominant container orchestration platform,withwidespread adoption across industries.However,its default pod-to-pod communicationmechanism introduces security vulnerabilities,particularly IP spoofing attacks.Attackers can exploit this weakness to impersonate legitimate pods,enabling unauthorized access,lateral movement,and large-scale Distributed Denial of Service(DDoS)attacks.Existing security mechanisms such as network policies and intrusion detection systems introduce latency and performance overhead,making them less effective in dynamic Kubernetes environments.This research presents PodCA,an eBPF-based security framework designed to detect and prevent IP spoofing in real time while minimizing performance impact.PodCA integrates with Kubernetes’Container Network Interface(CNI)and uses eBPF to monitor and validate packet metadata at the kernel level.It maintains a container network mapping table that tracks pod IP assignments,validates packet legitimacy before forwarding,and ensures network integrity.If an attack is detected,PodCA automatically blocks spoofed packets and,in cases of repeated attempts,terminates compromised pods to prevent further exploitation.Experimental evaluation on an AWS Kubernetes cluster demonstrates that PodCA detects and prevents spoofed packets with 100%accuracy.Additionally,resource consumption analysis reveals minimal overhead,with a CPU increase of only 2–3%per node and memory usage rising by 40–60 MB.These results highlight the effectiveness of eBPF in securing Kubernetes environments with low overhead,making it a scalable and efficient security solution for containerized applications.
基金supported by the National Key Research and Development Program of China(Grant No.2022YFE0134200)the National Natural Science Foundation of China(Grant No.12204214)+1 种基金the Fundamental Research Funds for the Central Universities(Grant No.GK202207012)QCYRCXM-2022-241。
文摘Multi-electron and multi-orbital effects play a crucial role in the interaction of strong laser fields with complex molecules.Here,multi-electron effects encompass not only electron-electron Coulomb interactions and exchangecorrelation effects but also the interference between the dynamics of different electron wave packets.
基金supported by the National Natural Science Foundation of China(62101300,62341130)the Youth Fund Program of the Beijing National Research Center for Information Science and Technology under Grant BNR2021RC01012the Open Research Fund Program of the Beijing National Research Center for Information Science and Technology under Grant BNR2021KF02001.
文摘Software-defined satellite networks(SDSNs)play an essential role in future networks.Due to the diverse service scenarios,SDSN faces the demand of packet processing for heterogeneous protocols.Existing packet switching typically works on one single protocol.For protocol-heterogeneous users,existing packet switch architectures have to construct multiple protocol-specific switching instances,resulting in severe resource waste.In this article,we propose the heterogeneous protocol-independent packet switch architecture(HISA).HISA employs a fast parsing structure to achieve efficient heterogeneous packet parsing and a novel match-action pipeline to achieve shared packet processing among heterogeneous users.HISA can also support the online configuration of switching behaviors.Use cases illustrate the effectiveness of applying HISA in SDSN.Numerical results show that compared to existing packet switching,HISA can significantly improve the resource utilization of SDSN.
文摘High-quality services in today’s mobile networks require stable delivery of bandwidth-intensive network content.Multipath QUIC(MPQUIC),as a multipath protocol that extends QUIC,can utilize multiple paths to support stable and efficient transmission.The standard coupled congestion control algorithm in MPQUIC synchronizes these paths to manage congestion,meeting fairness requirements and improving transmission efficiency.However,current algorithms’Congestion Window(CWND)reduction approach significantly decreases CWND upon packet loss,which lowers effective throughput,regardless of the congestion origin.Furthermore,the uncoupled Slow-Start(SS)in MPQUIC leads to independent exponential CWND growth on each path,potentially causing buffer overflow.To address these issues,we propose the CC-OLIA,which incorporates Packet Loss Classifcation(PLC)and Coupled Slow-Start(CSS).The PLC distinguishes between congestion-induced and random packet losses,adjusting CWND reduction accordingly to maintain throughput.Concurrently,the CSS module coordinates CWND growth during the SS,preventing abrupt increases.Implementation on MININET shows that CC-OLIA not only maintains fair performance but also enhances transmission efficiency across diverse network conditions.
基金supported by Institute for Information&Communications Technology Planning&Evaluation(IITP)grant funded by the Korea government(MSIT)(No.RS-2022-II221200)Convergence Security Core Talent Training Business(Chungnam National University).
文摘Pre-Authentication and Post-Connection(PAPC)plays a crucial role in realizing the Zero Trust security model by ensuring that access to network resources is granted only after successful authentication.While earlier approaches such as Port Knocking(PK)and Single Packet Authorization(SPA)introduced pre-authentication concepts,they suffer from limitations including plaintext communication,protocol dependency,reliance on dedicated clients,and inefficiency under modern network conditions.These constraints hinder their applicability in emerging distributed and resource-constrained environments such as AIoT and browser-based systems.To address these challenges,this study proposes a novel port-sequence-based PAPC scheme structured as a modular model comprising a client,server,and ephemeral Key Management System(KMS).The system employs the Advanced Encryption Standard(AES-128)to protect message confidentiality and uses a Hash-Based Message Authentication Code(HMAC-SHA256)to ensure integrity.Authentication messages are securely fragmented and mapped to destination port numbers using a signature-based avoidance algorithm,which prevents collisions with unsafe or reserved port ranges.The server observes incoming port sequences,retrieves the necessary keys from the KMS,reconstructs and verifies the encrypted data,and conditionally updates firewall policies.Unlike SPA,which requires decrypting all incoming payloads and imposes server-side overhead,the proposed system verifies only port-derived fragments,significantly reducing computational burden.Furthermore,it eliminates the need for raw socket access or custom clients,supporting browser-based operation and enabling protocol-independent deployment.Through a functional web-based prototype and emulated testing,the system achieved an F1-score exceeding 95%in detecting unauthorized access while maintaining low resource overhead.Although port sequence generation introduces some client-side cost,it remains lightweight and scalable.By tightly integrating lightweight cryptographic algorithms with a transport-layer communication model,this work presents a conceptually validated architecture that contributes a novel direction for interoperable and scalable Zero Trust enforcement in future network ecosystems.
基金supported by the National Natural Science Foundation of China (Nos. 22174075 and 22374082)the Haihe Laboratory of Sustainable Chemical Transformations。
文摘The hydration state of amphiphilic block copolymers during the self-assembly transition is closely related to the structure and properties of copolymers. In this study, the temperature-induced self-assembly of copolymer poly(N,N-dimethylacrylamide)-poly(diacetone acrylamide)(PDMAA_(30)-PDAAM_(60))_(2)in aqueous solution was monitored by near-infrared spectroscopy with water as a probe. The wavelet packet transform was employed to improve the spectral resolution. The spectral information of hydrated water surrounding the hydrophilic PDMAA and hydrophobic PDAAM blocks was then extracted, revealing the significant roles of water in morphological transition of the copolymer from spherical to worm-like micelles. Specifically, water molecules interacting with N atoms and C=O groups of the hydrophilic block gradually decrease during the morphological transition, while hydrogen-bond structures NH–CO of the hydrophobic block gradually break, bringing more water molecules into contact with the hydrophobic block. This work provides a foundation for exploring the role of water molecules during the self-assembly transition of complex block copolymers.
基金supported by the National Key Research and Development Program of China(Grant No.2022YFA1602502)the National Natural Science Foundation of China(Grant No.12450404).
文摘Rotational dynamics simulations of neutral O_(2)molecules driven by linearly,elliptically and circularly polarized femtosecond pulsed lasers are carried out using a full quantum time-dependent wave packet evolution method.Here,the direction of laser propagation is set along the z axis,and the polarization plane is restricted to the xy plane.The results indicate that the alignment of O_(2)molecules in the z direction is weakly affected by varying the ellipticity when the total laser intensity is held constant.For rotation within the xy plane,the linearly polarized laser significantly excites rotational motion,with the degree of excitation increasing as the ellipticity increases.In contrast,under the influence of a circularly polarized laser,the angular distribution of O_(2)molecules in the xy plane remains isotropic.Additionally,the effects of the initial rotational quantum number,the temperature of the O_(2)molecules and the nuclear spin on laser-induced alignment are discussed.
文摘Reliable and efficient communication is essential for Unmanned Aerial Vehicle(UAV)networks,especially in dynamic and resource-constrained environments such as disaster management,surveillance,and environmental monitoring.Frequent topology changes,high mobility,and limited energy availability pose significant challenges to maintaining stable and high-performance routing.Traditional routing protocols,such as Ad hoc On-Demand Distance Vector(AODV),Load-Balanced Optimized Predictive Ad hoc Routing(LB-OPAR),and Destination-Sequenced Distance Vector(DSDV),often experience performance degradation under such conditions.To address these limitations,this study evaluates the effectiveness of Dynamic Adaptive Routing(DAR),a protocol designed to adapt routing decisions in real time based on network dynamics and resource constraints.The research utilizes the Network Simulator 3(NS-3)platform to conduct controlled simulations,measuring key performance indicators such as latency,Packet Delivery Ratio(PDR),energy consumption,and throughput.Comparative analysis reveals that DAR consistently outperforms conventional protocols,achieving a 20%-30% reduction in latency,a 25% decrease in energy consumption,and marked improvements in throughput and PDR.These results highlight DAR’s ability to maintain high communication reliability while optimizing resource usage in challenging operational scenarios.By providing empirical evidence of DAR’s advantages in highly dynamic UAV network environments,this study contributes to advancing adaptive routing strategies.The findings not only validate DAR’s robustness and scalability but also lay the groundwork for integrating artificial intelligence-driven decision-making and real-world UAV deployment.Future work will explore cross-layer optimization,multi-UAV coordination,and experimental validation in field trials,aiming to further enhance communication resilience and energy efficiency in next-generation aerial networks.
基金supported by the National Natural Science Foundation of China under Grant No.62275176the Natural Science Foundation of Guangdong Province,China,under Grant No.2022A1515010084+1 种基金by Key Projects of Basic Research and Applied Basic Research in Universities of Guangdong Province,China,under Grants Nos.2021ZDZX1118 and 2022ZDZX1079supported by the NPRP 13S-0121-200126 Project with the Qatar National Research Fund(a member of the Qatar Foundation).
文摘We investigate the diffractive paraxial wave equation with an external potential,utilizing self-similarity and variable separation methods.The exact solution to this evolution equation,expressed through Scorer functions,gives rise to the new Scorer beams.We explore the dynamics of counterpropagating Scorer beams,as promising optical wave packets,focusing on their compression behavior.The Scorer beams are characterized by two key parameters:the attenuation factor and the initial pulse width.By appropriately adjusting these parameters,significant beam compression can be achieved.Specifically,increasing the attenuation factor enhances compression and raises pulse amplitude,while reducing the initial pulse width further amplifies these effects.Along the way,we observe interesting interference patterns of the counterpropagating Scorer beams that have never been seen before.This study introduces a novel approach to beam compression and opens new possibilities for practical applications of Scorer beams.
基金supported by the GHfund A(Grant No.ghfund202407013663)the Fundamental Research Funds for the Central Universities(Grant No.GK202207012)+4 种基金Shaanxi Province(Grant No.QCYRCXM-2022-241)the National Key Research and Development Program of China(Grant No.2022YFE0134200)Guangdong Basic and Applied Basic Research Foundation(Grant No.2025A1515011117)the Natural Science Foundation of Jilin Province(Grant No.20220101016JC)the National Natural Science Foundation of China(Grant Nos.12374238,11934004,and 11974230)。
文摘We present a graphics processing units(GPU)parallelization based three-dimensional time-dependent Schrödinger equation(3D-TDSE)code to simulate the interaction between single-active-electron atom/molecule and arbitrary types of laser pulses with either velocity gauge or length gauge in Cartesian coordinates.Split-operator method combined with fast Fourier transforms(FFT)is used to perform the time evolution.Sample applications in different scenarios,such as stationary state energies,photon ionization spectra,attosecond clocks,and high-order harmonic generation(HHG),are given for the hydrogen atom.Repeatable results can be obtained with the benchmark program PCTDSE,which is a 3DTDSE Fortran solver parallelized using message passing interface(MPI)library.With the help of GPU acceleration and vectorization strategy,our code running on a single NVIDIA 3090 RTX GPU can achieve about 10 times faster computation speed than PCTDSE running on a 144 Intel Xeon CPU cores server with the same accuracy.In addition,3D-GTDSE can also be modified slightly to simulate non-adiabatic dynamics involving the coupling of nuclear and electronic wave packets,as well as pure nuclear wave packet dynamics in the presence of strong laser fields within 3 dimensions.Additionally,we have also discussed the limitations and shortcomings of our code in utilizing GPU memory.The 3D-GTDSE code provides an alternative tool for studying the ultrafast nonlinear dynamics under strong laser fields.
基金This paper was partially supported by the National Natural Science Foundation of China under Crant No. 61072061111 Project of China under Crant No. B08004 the Fundamental Research Funds for the Central Universities under Grant No. 2009RC0122. References
文摘Based on the massive data collected with a passive network monitoring equipment placed in China＇s backbone, we present a deep insight into the network backbone traffic and evaluate various ways for inproving traffic classifying efficiency in this pa- per. In particular, the study has scrutinized the net- work traffic in terms of protocol types and signatures, flow length, and port distffoution, from which mean- ingful and interesting insights on the current Intemet of China from the perspective of both the packet and flow levels are derived. We show that the classifica- tion efficiency can be greatly irrproved by using the information of preferred ports of the network applica- tions. Quantitatively, we find two traffic duration thresholds, with which 40% of TCP flows and 70% of UDP flows can be excluded from classification pro- cessing while the in^act on classification accuracy is trivial, i.e., the classification accuracy can still reach a high level by saving 85% of the resources.
基金supported by the National Natural Science Foundation of China (Grant Nos. 40930950 and 40921160379)the Chinese Academy of Meteorological Sciences State Key Laboratory of Severe Weather (LaSW+1 种基金Grant No. 2011LASW-A01)the National Basic Research Project of China under Grant No. 2012CB417201
文摘The propagation of wave packets and its relationship with the subtropical jet was investigated for the period 26 29 January 2008 over southern China using ECMWF Interim re-analysis data. Wave packets propagated from the north to the south side of an upper front with eastward development along the upper front during this period. Due to the eastward development of propagation, the acceleration of geostrophic westerly winds shifted eastward along the front. There were two primary sources of the propagation of wave packets at around 30°N. The first was the temperature inversion layer below 500 hPa, and the second was baroclinic zones located along the polarward flank of the subtropical jet in the middle and upper troposphere. Most wave packets propagated horizontally from the baroclinic zones and then converged on the zero meridional gradients of zonal winds.
