Inspired by macroscale 3D pixel mechanical metamaterials and microscale straw-like carbon nanotube,we propose a design of multi-stable straw-like carbon nanotubes(MSCNT)via optimizing the structure of a unit to obtain...Inspired by macroscale 3D pixel mechanical metamaterials and microscale straw-like carbon nanotube,we propose a design of multi-stable straw-like carbon nanotubes(MSCNT)via optimizing the structure of a unit to obtain multiple stable states under dis-placement loading by molecular dynamics.The unit of MSCNT is mirror-symmetrically connected two truncated graphene cones with specific apex angles.By switching the LJ term in AIREBO potential,we verify that the bistability of unit is co-determined by snap-through instability and microscale adhesions.Moreover,we examine the validity of the multi-stability of the unit cells arranged in series and in parallels.Simulation results indicate that the MSCNT can achieve mechanical programmability in microscale,which triggers many potential applications in need of customizing nanos-cale mechanical behaviors.展开更多
This paper introduces the Integrated Security Embedded Resilience Architecture (ISERA) as an advanced resilience mechanism for Industrial Control Systems (ICS) and Operational Technology (OT) environments. The ISERA f...This paper introduces the Integrated Security Embedded Resilience Architecture (ISERA) as an advanced resilience mechanism for Industrial Control Systems (ICS) and Operational Technology (OT) environments. The ISERA framework integrates security by design principles, micro-segmentation, and Island Mode Operation (IMO) to enhance cyber resilience and ensure continuous, secure operations. The methodology deploys a Forward-Thinking Architecture Strategy (FTAS) algorithm, which utilises an industrial Intrusion Detection System (IDS) implemented with Python’s Network Intrusion Detection System (NIDS) library. The FTAS algorithm successfully identified and responded to cyber-attacks, ensuring minimal system disruption. ISERA has been validated through comprehensive testing scenarios simulating Denial of Service (DoS) attacks and malware intrusions, at both the IT and OT layers where it successfully mitigates the impact of malicious activity. Results demonstrate ISERA’s efficacy in real-time threat detection, containment, and incident response, thus ensuring the integrity and reliability of critical infrastructure systems. ISERA’s decentralised approach contributes to global net zero goals by optimising resource use and minimising environmental impact. By adopting a decentralised control architecture and leveraging virtualisation, ISERA significantly enhances the cyber resilience and sustainability of critical infrastructure systems. This approach not only strengthens defences against evolving cyber threats but also optimises resource allocation, reducing the system’s carbon footprint. As a result, ISERA ensures the uninterrupted operation of essential services while contributing to broader net zero goals.展开更多
Scientific reforms proposed in response to moral concerns about corrupted science are reminiscent of the Christian Reformation,which similarly formed a moral reorientation as a reaction to malpractices.In this study,w...Scientific reforms proposed in response to moral concerns about corrupted science are reminiscent of the Christian Reformation,which similarly formed a moral reorientation as a reaction to malpractices.In this study,we compare these moral reorientation processes to contextualize two different moral programmes of the scientific reform movement and their sociopolitical conditions.We argue that such an explication of moral programmes is vital to build legitimacy and reflect on value-prioritization.While epistemic programmes are foregrounded,moral programmes also play a crucial role in shaping science,and different moral programmes offer different promises for the sustained support of credible,reliable,fair and equitable science.We discuss the virtue and equity programmes,and through interrogating both programmes in relation to the Reformation,we display the relevance of sociopolitical contexts to how key values operate in science and generate orders of worth.These insights aim to stimulate debate about the conditions for opting for either of these moral programmes.In our view,not all moral programmes offer equal promise for the sustained support of credible,equitable and fair science.展开更多
Persistent flows are defined as network flows that persist over multiple time intervals and continue to exhibit activity over extended periods,which are critical for identifying long-term behaviors and subtle security...Persistent flows are defined as network flows that persist over multiple time intervals and continue to exhibit activity over extended periods,which are critical for identifying long-term behaviors and subtle security threats.Programmable switches provide line-rate packet processing to meet the requirements of high-speed network environments,yet they are fundamentally limited in computational and memory resources.Accurate and memoryefficient persistent flow detection on programmable switches is therefore essential.However,existing approaches often rely on fixed-window sketches or multiple sketches instances,which either suffer from insufficient temporal precision or incur substantial memory overhead,making them ineffective on programmable switches.To address these challenges,we propose SP-Sketch,an innovative sliding-window-based sketch that leverages a probabilistic update mechanism to emulate slot expiration without maintaining multiple sketch instances.This innovative design significantly reduces memory consumption while preserving high detection accuracy across multiple time intervals.We provide rigorous theoretical analyses of the estimation errors,deriving precise error bounds for the proposed method,and validate our approach through comprehensive implementations on both P4 hardware switches(with Intel Tofino ASIC)and software switches(i.e.,BMv2).Experimental evaluations using real-world traffic traces demonstrate that SP-Sketch outperforms traditional methods,improving accuracy by up to 20%over baseline sliding window approaches and enhancing recall by 5%compared to non-sliding alternatives.Furthermore,SP-Sketch achieves a significant reduction in memory utilization,reducing memory consumption by up to 65%compared to traditional methods,while maintaining a robust capability to accurately track persistent flow behavior over extended time periods.展开更多
This paper presents the development of a thermoplastic shape memory rubber that can be programmed at human body temperature for comfortable fitting applications.We hybridized commercially available thermoplastic rubbe...This paper presents the development of a thermoplastic shape memory rubber that can be programmed at human body temperature for comfortable fitting applications.We hybridized commercially available thermoplastic rubber(TPR)used in the footwear industry with un-crosslinked polycaprolactone(PCL)to create two samples,namely TP6040 and TP7030.The shape memory behavior,elasticity,and thermo-mechanical response of these rubbers were systematically investigated.The experimental results demonstrated outstanding shape memory performance,with both samples achieving shape fixity ratios(Rf)and shape recovery ratios(R_(r))exceeding 94%.TP6040 exhibited a fitting time of 80 s at body temperature(37℃),indicating a rapid response for shape fixing.The materials also showed good elasticity before and after programming,which is crucial for comfort fitting.These findings suggest that the developed shape memory thermoplastic rubber has potential applications in personalized comfort fitting products,offering advantages over traditional customization techniques in terms of efficiency and cost-effectiveness.展开更多
Advanced programmable metamaterials with heterogeneous microstructures have become increasingly prevalent in scientific and engineering disciplines attributed to their tunable properties.However,exploring the structur...Advanced programmable metamaterials with heterogeneous microstructures have become increasingly prevalent in scientific and engineering disciplines attributed to their tunable properties.However,exploring the structure-property relationship in these materials,including forward prediction and inverse design,presents substantial challenges.The inhomogeneous microstructures significantly complicate traditional analytical or simulation-based approaches.Here,we establish a novel framework that integrates the machine learning(ML)-encoded multiscale computational method for forward prediction and Bayesian optimization for inverse design.Unlike prior end-to-end ML methods limited to specific problems,our framework is both load-independent and geometry-independent.This means that a single training session for a constitutive model suffices to tackle various problems directly,eliminating the need for repeated data collection or training.We demonstrate the efficacy and efficiency of this framework using metamaterials with designable elliptical holes or lattice honeycombs microstructures.Leveraging accelerated forward prediction,we can precisely customize the stiffness and shape of metamaterials under diverse loading scenarios,and extend this capability to multi-objective customization seamlessly.Moreover,we achieve topology optimization for stress alleviation at the crack tip,resulting in a significant reduction of Mises stress by up to 41.2%and yielding a theoretical interpretable pattern.This framework offers a general,efficient and precise tool for analyzing the structure-property relationships of novel metamaterials.展开更多
Software-Defined Perimeter(SDP)provides a logical perimeter to restrict access to services.However,due to the security vulnerability of a single controller and the programmability lack of a gateway,existing SDP is fac...Software-Defined Perimeter(SDP)provides a logical perimeter to restrict access to services.However,due to the security vulnerability of a single controller and the programmability lack of a gateway,existing SDP is facing challenges.To solve the above problems,we propose a flexible and secure SDP mechanism named Mimic SDP(MSDP).MSDP consists of endogenous secure controllers and a dynamic gateway.The controllers avoid single point failure by heterogeneity and redundancy.And the dynamic gateway realizes flexible forwarding in programmable data plane by changing the processing of packet construction and deconstruction,thereby confusing the potential adversary.Besides,we propose a Markov model to evaluate the security of our SDP framework.We implement a prototype of MSDP and evaluate it in terms of functionality,performance,and scalability in different groups of systems and languages.Evaluation results demonstrate that MSDP can provide a secure connection of 93.38%with a cost of 6.34%under reasonable configuration.展开更多
Kirigami,through introducing cuts into a thin sheet,can greatly improve the stretchability of structures and also generate complex patterns,showing potentials in various applications.Interestingly,even with the same c...Kirigami,through introducing cuts into a thin sheet,can greatly improve the stretchability of structures and also generate complex patterns,showing potentials in various applications.Interestingly,even with the same cutting pattern,the mechanical response of kirigami metamaterials can exhibit significant differences depending on the cutting angles in respect to the loading direction.In this work,we investigate the structural deformation of kirigami metamaterials with square domains and varied cutting angles of 0°and 45°.We further introduce a second level of cutting on the basis of the first cutting pattern.By combining experiments and finite element simulations,it is found that,compared to the commonly used 0°cuts,the two-level kirigami metamaterials with 45°cuts exhibit a unique alternating arrangement phenomenon of expanded/unexpanded states in the loading process,which also results in distinct stress–strain response.Through tuning the cutting patterns of metamaterials with 45°cuts,precise control of the rotation of the kirigami unit is realized,leading to kirigami metamaterials with encryption properties.The current work demonstrates the programmability of structural deformation in hierarchical kirigami metamaterials through controlling the local cutting modes.展开更多
Chiral metamaterials are manmade structures with extraordinary mechanical properties derived from their special geometric design instead of chemical composition.To make the mechanical deformation programmable,the non-...Chiral metamaterials are manmade structures with extraordinary mechanical properties derived from their special geometric design instead of chemical composition.To make the mechanical deformation programmable,the non-uniform rational B-spline(NURBS)curves are taken to replace the traditional ligament boundaries of the chiral structure.The Neural networks are innovatively inserted into the calculation of mechanical properties of the chiral structure instead of finite element methods to improve computational efficiency.For the problem of finding structure configuration with specified mechanical properties,such as Young’s modulus,Poisson’s ratio or deformation,an inverse design method using the Neural network-based proxy model is proposed to build the relationship between mechanical properties and geometric configuration.To satisfy some more complex deformation requirements,a non-homogeneous inverse design method is proposed and verified through simulation and experiments.Numerical and test results reveal the high computational efficiency and accuracy of the proposed method in the design of chiral metamaterials.展开更多
UNDP official discusses transforming Africa-China partnerships through innovation,trade,and green growth Representatives from numerous interna-tional organisations,including the United Nations Development Programme(UN...UNDP official discusses transforming Africa-China partnerships through innovation,trade,and green growth Representatives from numerous interna-tional organisations,including the United Nations Development Programme(UNDP),attended the fourth China-Africa Economic and Trade Expo(CAETE),held in June in Changsha,Hunan Province.Among them was Ahunna Eziakonwa,UN assistant secretary general and director of the UNDP Regional Bureau for Africa,who took part in several activities at the expo.Her mission focused on promoting sustainable development across Africa through trade,innovation,and responsible investment.展开更多
Smart elastomers have attracted great interest due to their excellent adaptability to changing environments and affinity to living organisms,characterized by their ability to undergo programmable deformations or prope...Smart elastomers have attracted great interest due to their excellent adaptability to changing environments and affinity to living organisms,characterized by their ability to undergo programmable deformations or property changes in response to external stimuli(e.g.,heat,light,pH,or electric/magnetic fields).They exhibit huge potential to drive the innovation of soft actuators,robotics,biomedical devices,and wearable electronics.This special issue of Chinese Journal of Polymer Science(CJPS)is dedicated to showcasing cutting-edge advancements in liquid crystal elastomers,hydrogels and the related soft actuators,with a focus on the design,synthesis,characterization,and application of stimuli-responsive soft elastomers and their integration into functional actuation systems.展开更多
With the rapid development of low altitude economic industry,low altitude adhoc network technology has been getting more and more intensive attention.In the adhoc network protocol designed in this paper,the convolutio...With the rapid development of low altitude economic industry,low altitude adhoc network technology has been getting more and more intensive attention.In the adhoc network protocol designed in this paper,the convolutional code used is(3,1,7),and the design of a low power Viterbi decoder adapted to multi-rate variations is proposed.In the traditional Viterbi decoding method,the high complexity of path metric(PM)accumulation and Euclidean distance computation leads to the problems of low efficiency and large storage resources in the decoder.In this paper,an improved add compare select(ACS)algorithm,a generalized formula for branch metric(BM)based on Manhattan distance,and a method to reduce the accumulated PM for different Viterbi decoders are put forward.A simulation environment based on Vivado and Matlab to verify the accuracy and effectiveness of the proposed Viterbi decoder is also established.The experimental results show that the total power consumption is reduced by 15.58%while the decoding accuracy of the Viterbi decoder is guaranteed,which meets the design requirements of a low power Viterbi decoder.展开更多
On April 19th,"the Youth Table Tennis Programme—Photo Exhibition of Zhou Enlai and the Bandung Conference&China-ASEAN(Indonesia)Youth Table Tennis Training Camp"opened in Jakarta,Indonesia.The event was...On April 19th,"the Youth Table Tennis Programme—Photo Exhibition of Zhou Enlai and the Bandung Conference&China-ASEAN(Indonesia)Youth Table Tennis Training Camp"opened in Jakarta,Indonesia.The event was guided by the Chinese Embassy in Indonesia and co-organised by the ASEAN-China Centre(ACC),the Memorial to Zhou Enlai and Deng Yingchao,the China Friendship Foundation for Peace and Development,the Beijing One Heart Sphere Charity Foundation,and the Enlai Foundation.展开更多
A programmable low-profile array antenna based on nematic liquid crystals(NLCs)is proposed.Each antenna unit comprises a square patch radiating structure and a tunable NLC-based phase shifter capable of achieving a ph...A programmable low-profile array antenna based on nematic liquid crystals(NLCs)is proposed.Each antenna unit comprises a square patch radiating structure and a tunable NLC-based phase shifter capable of achieving a phase shift exceeding 360°with high linearity.First,the above 64 antenna units are periodically arranged into an 8×8 NLC-based antenna array,and the bias voltage of the NLC-based phase shifter loaded on the antenna unit is adjusted through the control of the field-programmable gate array(FPGA)programming sequences.This configuration enables precise phase changes for all 64 channels.Numerical simulation,sample processing,and experimental measurements of the antenna array are conducted to validate the performance of the antenna.The numerical and experimental results demonstrate that the proposed antenna performs well within the frequency range of 19.5-20.5 GHz,with a 3 dB relative bandwidth of 10%and a maximum main lobe gain of 14.1 dBi.A maximum scanning angle of±34°is achieved through the adjustment of the FPGA programming sequence.This NLC-based programmable array antenna shows promising potential for applications in satellite communication.展开更多
With the rapid advancement of information technology,the quality assurance and evaluation of software engineering education have become pivotal concerns for higher education institutions.In this paper,we focus on a co...With the rapid advancement of information technology,the quality assurance and evaluation of software engineering education have become pivotal concerns for higher education institutions.In this paper,we focus on a comparative study of software engineering education in China and Europe,aiming to explore the theoretical frameworks and practical pathways employed in both regions.Initially,we introduce and contrast the engineering education accreditation systems of China and Europe,including the Chinese engineering education accreditation framework and the European EUR-ACE(European Accreditation of Engineering Programmes)standards,highlighting their core principles and evaluation methodologies.Subsequently,we provide case studies of several universities in China and Europe,such as Sun Yat-sen University,Tsinghua University,Technical University of Munich,and Imperial College London.Finally,we offer recommendations to foster mutual learning and collaboration between Chinese and European institutions,aiming to enhance the overall quality of software engineering education globally.This work provides valuable insights for educational administrators,faculty members,and policymakers,contributing to the ongoing improvement and innovative development of software engineering education in China and Europe.展开更多
In recent years,materials with asymmetric mechanical response properties(mechanical Janus materials)have been found possess numerous potential applications,i.e.shock absorption and vibration isolation.In this study,we...In recent years,materials with asymmetric mechanical response properties(mechanical Janus materials)have been found possess numerous potential applications,i.e.shock absorption and vibration isolation.In this study,we propose a novel mechanical Janus lattice whose asymmetric mechanical response can be switched in orientation by a plug.Through finite element analysis and experimental verification,this lattice exhibits asymmetric displacement responses to symmetric forces.Furthermore,with such a plug structure inside,individual lattices can switch the orientation of asymmetry and thus achieve reprogrammable design of a mechanical structure with chained lattices.The reprogrammable asymmetry of this material will offer multiple functions in design of mechanical metamaterials.展开更多
A digital data-acquisition system based on XIA LLC products was used in a complex nuclear reaction experiment using radioactive ion beams.A flexible trigger system based on a field-programmable gate array(FPGA)paramet...A digital data-acquisition system based on XIA LLC products was used in a complex nuclear reaction experiment using radioactive ion beams.A flexible trigger system based on a field-programmable gate array(FPGA)parametrization was developed to adapt to different experimental sizes.A user-friendly interface was implemented,which allows converting script language expressions into FPGA internal control parameters.The proposed digital system can be combined with a conventional analog data acquisition system to provide more flexibility.The performance of the combined system was veri-fied using experimental data.展开更多
The area of land that is affected by soil erosion in the Yangtze River has been reduced by 146,000 km~2(accounting for 27%of the entire Yangtze River)since 2000.However,the contributions of different tributaries to th...The area of land that is affected by soil erosion in the Yangtze River has been reduced by 146,000 km~2(accounting for 27%of the entire Yangtze River)since 2000.However,the contributions of different tributaries to this soil erosion decline and the underlying causes have not been determined.Here we quantify the soil erosion decline in the Yangtze River and the impacts of the Grain-for-Green Programme(GFGP)and climate change using the RUSLE model and statistical methods.The results were as follows:(1)After the implementation of the GFGP,soil erosion decreased in ten sub-basins excluding the Dongting Lake catchment;(2)Soil erosion was mainly affected by the GFGP and the rainfall erosivity.Specifically,the contributions of the GFGP and rainfall erosivity to soil erosion decline are estimated to be 70.12%and 29.88%,respectively.(3)“Scenario#9”means the combination of slope(15°-25°)of retired farmland converted to shrub land and slope(>25°)of retired farmland converted to grassland.Considering scenario feasibility and management targets,Scenario#9 was the most appropriate land use scenario for the Yangtze River.This study offers insights into managing and reducing soil erosion in the future.展开更多
Manipulating the expression of synaptic plasticity of neuromorphic devices provides fascinating opportunities to develop hardware platforms for artifi-cial intelligence.However,great efforts have been devoted to explo...Manipulating the expression of synaptic plasticity of neuromorphic devices provides fascinating opportunities to develop hardware platforms for artifi-cial intelligence.However,great efforts have been devoted to exploring biomimetic mechanisms of plasticity simulation in the last few years.Recent progress in various plasticity modulation techniques has pushed the research of synaptic electronics from static plasticity simulation to dynamic plasticity modulation,improving the accuracy of neuromorphic computing and providing strategies for implementing neuromorphic sensing functions.Herein,several fascinating strategies for synap-tic plasticity modulation through chemical techniques,device structure design,and physical signal sensing are reviewed.For chemical techniques,the underly-ing mechanisms for the modification of functional materials were clarified and its effect on the expression of synaptic plasticity was also highlighted.Based on device structure design,the reconfigurable operation of neuromorphic devices was well demonstrated to achieve programmable neuromorphic functions.Besides,integrating the sensory units with neuromorphic processing circuits paved a new way to achieve human-like intelligent perception under the modulation of physical signals such as light,strain,and temperature.Finally,considering that the relevant technology is still in the basic exploration stage,some prospects or development suggestions are put forward to promote the development of neuromorphic devices.展开更多
Inspired by the way sea turtles rely on the Earth’s magnetic field for navigation and locomotion,a novel magnetic soft robotic turtle with programmable magnetization has been developed and investigated to achieve bio...Inspired by the way sea turtles rely on the Earth’s magnetic field for navigation and locomotion,a novel magnetic soft robotic turtle with programmable magnetization has been developed and investigated to achieve biomimetic locomotion patterns such as straight-line swimming and turning swimming.The soft robotic turtle(12.50 mm in length and 0.24 g in weight)is integrated with an Ecoflex-based torso and four magnetically programmed acrylic elastomer VHB-based limbs containing samarium-iron–nitrogen particles,and was able to carry a load more than twice its own weight.Similar to the limb locomotion characteristics of sea turtles,the magnetic torque causes the four limbs to mimic sinusoidal bending deformation under the influence of an external magnetic field,so that the turtle swims continuously forward.Significantly,when the bending deformation magnitudes of its left and right limbs differ,the soft robotic turtle switches from straight-line to turning swimming at 6.334 rad/s.Furthermore,the tracking swimming activities of the soft robotic turtle along specific planned paths,such as square-shaped,S-shaped,and double U-shaped maze,is anticipated to be utilized for special detection and targeted drug delivery,among other applications owing to its superior remote directional control ability.展开更多
基金the National Natural Science Foundation of China(Nos.12225201 and 12102021)the China Postdoctoral Science Foundation(No.2020M680287)are gratefully acknowledged.
文摘Inspired by macroscale 3D pixel mechanical metamaterials and microscale straw-like carbon nanotube,we propose a design of multi-stable straw-like carbon nanotubes(MSCNT)via optimizing the structure of a unit to obtain multiple stable states under dis-placement loading by molecular dynamics.The unit of MSCNT is mirror-symmetrically connected two truncated graphene cones with specific apex angles.By switching the LJ term in AIREBO potential,we verify that the bistability of unit is co-determined by snap-through instability and microscale adhesions.Moreover,we examine the validity of the multi-stability of the unit cells arranged in series and in parallels.Simulation results indicate that the MSCNT can achieve mechanical programmability in microscale,which triggers many potential applications in need of customizing nanos-cale mechanical behaviors.
基金funded by the Office of Gas and Electricity Markets(Ofgem)and supported by De Montfort University(DMU)and Nottingham Trent University(NTU),UK.
文摘This paper introduces the Integrated Security Embedded Resilience Architecture (ISERA) as an advanced resilience mechanism for Industrial Control Systems (ICS) and Operational Technology (OT) environments. The ISERA framework integrates security by design principles, micro-segmentation, and Island Mode Operation (IMO) to enhance cyber resilience and ensure continuous, secure operations. The methodology deploys a Forward-Thinking Architecture Strategy (FTAS) algorithm, which utilises an industrial Intrusion Detection System (IDS) implemented with Python’s Network Intrusion Detection System (NIDS) library. The FTAS algorithm successfully identified and responded to cyber-attacks, ensuring minimal system disruption. ISERA has been validated through comprehensive testing scenarios simulating Denial of Service (DoS) attacks and malware intrusions, at both the IT and OT layers where it successfully mitigates the impact of malicious activity. Results demonstrate ISERA’s efficacy in real-time threat detection, containment, and incident response, thus ensuring the integrity and reliability of critical infrastructure systems. ISERA’s decentralised approach contributes to global net zero goals by optimising resource use and minimising environmental impact. By adopting a decentralised control architecture and leveraging virtualisation, ISERA significantly enhances the cyber resilience and sustainability of critical infrastructure systems. This approach not only strengthens defences against evolving cyber threats but also optimises resource allocation, reducing the system’s carbon footprint. As a result, ISERA ensures the uninterrupted operation of essential services while contributing to broader net zero goals.
基金supported by the German Federal Ministry of Education and Research(BMBF)through their award of the K?te Hamburger Kolleg‘Cultures of Research’Senior Research Fellowship to Bart Penders
文摘Scientific reforms proposed in response to moral concerns about corrupted science are reminiscent of the Christian Reformation,which similarly formed a moral reorientation as a reaction to malpractices.In this study,we compare these moral reorientation processes to contextualize two different moral programmes of the scientific reform movement and their sociopolitical conditions.We argue that such an explication of moral programmes is vital to build legitimacy and reflect on value-prioritization.While epistemic programmes are foregrounded,moral programmes also play a crucial role in shaping science,and different moral programmes offer different promises for the sustained support of credible,reliable,fair and equitable science.We discuss the virtue and equity programmes,and through interrogating both programmes in relation to the Reformation,we display the relevance of sociopolitical contexts to how key values operate in science and generate orders of worth.These insights aim to stimulate debate about the conditions for opting for either of these moral programmes.In our view,not all moral programmes offer equal promise for the sustained support of credible,equitable and fair science.
基金supported by the National Undergraduate Innovation and Entrepreneurship Training Program of China(Project No.202510559076)at Jinan University,a nationwide initiative administered by the Ministry of Educationthe National Natural Science Foundation of China(NSFC)under Grant No.62172189.
文摘Persistent flows are defined as network flows that persist over multiple time intervals and continue to exhibit activity over extended periods,which are critical for identifying long-term behaviors and subtle security threats.Programmable switches provide line-rate packet processing to meet the requirements of high-speed network environments,yet they are fundamentally limited in computational and memory resources.Accurate and memoryefficient persistent flow detection on programmable switches is therefore essential.However,existing approaches often rely on fixed-window sketches or multiple sketches instances,which either suffer from insufficient temporal precision or incur substantial memory overhead,making them ineffective on programmable switches.To address these challenges,we propose SP-Sketch,an innovative sliding-window-based sketch that leverages a probabilistic update mechanism to emulate slot expiration without maintaining multiple sketch instances.This innovative design significantly reduces memory consumption while preserving high detection accuracy across multiple time intervals.We provide rigorous theoretical analyses of the estimation errors,deriving precise error bounds for the proposed method,and validate our approach through comprehensive implementations on both P4 hardware switches(with Intel Tofino ASIC)and software switches(i.e.,BMv2).Experimental evaluations using real-world traffic traces demonstrate that SP-Sketch outperforms traditional methods,improving accuracy by up to 20%over baseline sliding window approaches and enhancing recall by 5%compared to non-sliding alternatives.Furthermore,SP-Sketch achieves a significant reduction in memory utilization,reducing memory consumption by up to 65%compared to traditional methods,while maintaining a robust capability to accurately track persistent flow behavior over extended time periods.
基金supported by the Aeronautical Science Foundation of China(Grant Nos.2024Z009052003,20230038052001 and 20230015052002)the Third Batch of Science and Technology Plan Projects in Changzhou City in 2023(Applied Basic Research,Grant No.CJ20230080).
文摘This paper presents the development of a thermoplastic shape memory rubber that can be programmed at human body temperature for comfortable fitting applications.We hybridized commercially available thermoplastic rubber(TPR)used in the footwear industry with un-crosslinked polycaprolactone(PCL)to create two samples,namely TP6040 and TP7030.The shape memory behavior,elasticity,and thermo-mechanical response of these rubbers were systematically investigated.The experimental results demonstrated outstanding shape memory performance,with both samples achieving shape fixity ratios(Rf)and shape recovery ratios(R_(r))exceeding 94%.TP6040 exhibited a fitting time of 80 s at body temperature(37℃),indicating a rapid response for shape fixing.The materials also showed good elasticity before and after programming,which is crucial for comfort fitting.These findings suggest that the developed shape memory thermoplastic rubber has potential applications in personalized comfort fitting products,offering advantages over traditional customization techniques in terms of efficiency and cost-effectiveness.
基金supported by the National Natural Science Foundation of China (Grant Nos.12102021,12372105,12172026,and 12225201)the Fundamental Research Funds for the Central Universities and the Academic Excellence Foundation of BUAA for PhD Students.
文摘Advanced programmable metamaterials with heterogeneous microstructures have become increasingly prevalent in scientific and engineering disciplines attributed to their tunable properties.However,exploring the structure-property relationship in these materials,including forward prediction and inverse design,presents substantial challenges.The inhomogeneous microstructures significantly complicate traditional analytical or simulation-based approaches.Here,we establish a novel framework that integrates the machine learning(ML)-encoded multiscale computational method for forward prediction and Bayesian optimization for inverse design.Unlike prior end-to-end ML methods limited to specific problems,our framework is both load-independent and geometry-independent.This means that a single training session for a constitutive model suffices to tackle various problems directly,eliminating the need for repeated data collection or training.We demonstrate the efficacy and efficiency of this framework using metamaterials with designable elliptical holes or lattice honeycombs microstructures.Leveraging accelerated forward prediction,we can precisely customize the stiffness and shape of metamaterials under diverse loading scenarios,and extend this capability to multi-objective customization seamlessly.Moreover,we achieve topology optimization for stress alleviation at the crack tip,resulting in a significant reduction of Mises stress by up to 41.2%and yielding a theoretical interpretable pattern.This framework offers a general,efficient and precise tool for analyzing the structure-property relationships of novel metamaterials.
基金supported by the National Key Research and Development Program of China(Grant No.2022YFB2901304)。
文摘Software-Defined Perimeter(SDP)provides a logical perimeter to restrict access to services.However,due to the security vulnerability of a single controller and the programmability lack of a gateway,existing SDP is facing challenges.To solve the above problems,we propose a flexible and secure SDP mechanism named Mimic SDP(MSDP).MSDP consists of endogenous secure controllers and a dynamic gateway.The controllers avoid single point failure by heterogeneity and redundancy.And the dynamic gateway realizes flexible forwarding in programmable data plane by changing the processing of packet construction and deconstruction,thereby confusing the potential adversary.Besides,we propose a Markov model to evaluate the security of our SDP framework.We implement a prototype of MSDP and evaluate it in terms of functionality,performance,and scalability in different groups of systems and languages.Evaluation results demonstrate that MSDP can provide a secure connection of 93.38%with a cost of 6.34%under reasonable configuration.
基金supported by the National Natural Science Foundation of China(Grant Nos.12102392 and 12272341)the Zhejiang Provincial Natural Science Foundation of China(Grant No.LQ21A020008).
文摘Kirigami,through introducing cuts into a thin sheet,can greatly improve the stretchability of structures and also generate complex patterns,showing potentials in various applications.Interestingly,even with the same cutting pattern,the mechanical response of kirigami metamaterials can exhibit significant differences depending on the cutting angles in respect to the loading direction.In this work,we investigate the structural deformation of kirigami metamaterials with square domains and varied cutting angles of 0°and 45°.We further introduce a second level of cutting on the basis of the first cutting pattern.By combining experiments and finite element simulations,it is found that,compared to the commonly used 0°cuts,the two-level kirigami metamaterials with 45°cuts exhibit a unique alternating arrangement phenomenon of expanded/unexpanded states in the loading process,which also results in distinct stress–strain response.Through tuning the cutting patterns of metamaterials with 45°cuts,precise control of the rotation of the kirigami unit is realized,leading to kirigami metamaterials with encryption properties.The current work demonstrates the programmability of structural deformation in hierarchical kirigami metamaterials through controlling the local cutting modes.
基金supported by the National Natural Science Foundation of China(grant numbers 11972287 and 12072266)the State Key Laboratory of Structural Analysis,Optimization and CAE Software for Industrial Equipment(GZ23106)+1 种基金the National Key Laboratory of Aircraft Configuration Design(No.2023-JCJQ-LB-070)the Fundamental Research Funds for the Central Universities.
文摘Chiral metamaterials are manmade structures with extraordinary mechanical properties derived from their special geometric design instead of chemical composition.To make the mechanical deformation programmable,the non-uniform rational B-spline(NURBS)curves are taken to replace the traditional ligament boundaries of the chiral structure.The Neural networks are innovatively inserted into the calculation of mechanical properties of the chiral structure instead of finite element methods to improve computational efficiency.For the problem of finding structure configuration with specified mechanical properties,such as Young’s modulus,Poisson’s ratio or deformation,an inverse design method using the Neural network-based proxy model is proposed to build the relationship between mechanical properties and geometric configuration.To satisfy some more complex deformation requirements,a non-homogeneous inverse design method is proposed and verified through simulation and experiments.Numerical and test results reveal the high computational efficiency and accuracy of the proposed method in the design of chiral metamaterials.
文摘UNDP official discusses transforming Africa-China partnerships through innovation,trade,and green growth Representatives from numerous interna-tional organisations,including the United Nations Development Programme(UNDP),attended the fourth China-Africa Economic and Trade Expo(CAETE),held in June in Changsha,Hunan Province.Among them was Ahunna Eziakonwa,UN assistant secretary general and director of the UNDP Regional Bureau for Africa,who took part in several activities at the expo.Her mission focused on promoting sustainable development across Africa through trade,innovation,and responsible investment.
文摘Smart elastomers have attracted great interest due to their excellent adaptability to changing environments and affinity to living organisms,characterized by their ability to undergo programmable deformations or property changes in response to external stimuli(e.g.,heat,light,pH,or electric/magnetic fields).They exhibit huge potential to drive the innovation of soft actuators,robotics,biomedical devices,and wearable electronics.This special issue of Chinese Journal of Polymer Science(CJPS)is dedicated to showcasing cutting-edge advancements in liquid crystal elastomers,hydrogels and the related soft actuators,with a focus on the design,synthesis,characterization,and application of stimuli-responsive soft elastomers and their integration into functional actuation systems.
基金Supported by the National Natural Science Foundation of China(No.62103257).
文摘With the rapid development of low altitude economic industry,low altitude adhoc network technology has been getting more and more intensive attention.In the adhoc network protocol designed in this paper,the convolutional code used is(3,1,7),and the design of a low power Viterbi decoder adapted to multi-rate variations is proposed.In the traditional Viterbi decoding method,the high complexity of path metric(PM)accumulation and Euclidean distance computation leads to the problems of low efficiency and large storage resources in the decoder.In this paper,an improved add compare select(ACS)algorithm,a generalized formula for branch metric(BM)based on Manhattan distance,and a method to reduce the accumulated PM for different Viterbi decoders are put forward.A simulation environment based on Vivado and Matlab to verify the accuracy and effectiveness of the proposed Viterbi decoder is also established.The experimental results show that the total power consumption is reduced by 15.58%while the decoding accuracy of the Viterbi decoder is guaranteed,which meets the design requirements of a low power Viterbi decoder.
文摘On April 19th,"the Youth Table Tennis Programme—Photo Exhibition of Zhou Enlai and the Bandung Conference&China-ASEAN(Indonesia)Youth Table Tennis Training Camp"opened in Jakarta,Indonesia.The event was guided by the Chinese Embassy in Indonesia and co-organised by the ASEAN-China Centre(ACC),the Memorial to Zhou Enlai and Deng Yingchao,the China Friendship Foundation for Peace and Development,the Beijing One Heart Sphere Charity Foundation,and the Enlai Foundation.
基金The National Natural Science Foundation of China(No.62401168,62401139,62401170)China Postdoctoral Science Foundation(No.2023MD744197)+2 种基金Postdoctoral Fellowship Program of CPSF(No.GZC20230631)Project for Enhancing Young and Middle-aged Teacher’s Research Basis Ability in Colleges of Guangxi(No.2023KY0218)Guangxi Key Laboratory Foundation of Optoelectronic Information Processing(No.GD23102)。
文摘A programmable low-profile array antenna based on nematic liquid crystals(NLCs)is proposed.Each antenna unit comprises a square patch radiating structure and a tunable NLC-based phase shifter capable of achieving a phase shift exceeding 360°with high linearity.First,the above 64 antenna units are periodically arranged into an 8×8 NLC-based antenna array,and the bias voltage of the NLC-based phase shifter loaded on the antenna unit is adjusted through the control of the field-programmable gate array(FPGA)programming sequences.This configuration enables precise phase changes for all 64 channels.Numerical simulation,sample processing,and experimental measurements of the antenna array are conducted to validate the performance of the antenna.The numerical and experimental results demonstrate that the proposed antenna performs well within the frequency range of 19.5-20.5 GHz,with a 3 dB relative bandwidth of 10%and a maximum main lobe gain of 14.1 dBi.A maximum scanning angle of±34°is achieved through the adjustment of the FPGA programming sequence.This NLC-based programmable array antenna shows promising potential for applications in satellite communication.
基金supported by the Guangdong Higher Education Association’s“14th Five Year Plan”2024 Higher Education Research Project(24GYB03)the Natural Science Foundation of Guangdong Province(2024A1515010255)。
文摘With the rapid advancement of information technology,the quality assurance and evaluation of software engineering education have become pivotal concerns for higher education institutions.In this paper,we focus on a comparative study of software engineering education in China and Europe,aiming to explore the theoretical frameworks and practical pathways employed in both regions.Initially,we introduce and contrast the engineering education accreditation systems of China and Europe,including the Chinese engineering education accreditation framework and the European EUR-ACE(European Accreditation of Engineering Programmes)standards,highlighting their core principles and evaluation methodologies.Subsequently,we provide case studies of several universities in China and Europe,such as Sun Yat-sen University,Tsinghua University,Technical University of Munich,and Imperial College London.Finally,we offer recommendations to foster mutual learning and collaboration between Chinese and European institutions,aiming to enhance the overall quality of software engineering education globally.This work provides valuable insights for educational administrators,faculty members,and policymakers,contributing to the ongoing improvement and innovative development of software engineering education in China and Europe.
基金supported by the National Natural Science Foundation of China(Grant Nos.52075411 and U1913213)Shaanxi Key Research and Development Program(Grant No.2020ZDLGY06-11).
文摘In recent years,materials with asymmetric mechanical response properties(mechanical Janus materials)have been found possess numerous potential applications,i.e.shock absorption and vibration isolation.In this study,we propose a novel mechanical Janus lattice whose asymmetric mechanical response can be switched in orientation by a plug.Through finite element analysis and experimental verification,this lattice exhibits asymmetric displacement responses to symmetric forces.Furthermore,with such a plug structure inside,individual lattices can switch the orientation of asymmetry and thus achieve reprogrammable design of a mechanical structure with chained lattices.The reprogrammable asymmetry of this material will offer multiple functions in design of mechanical metamaterials.
基金This work was supported by the National Key R&D Program of China(Nos.2023YFA1606403 and 2023YFE0101600)the National Natural Science Foundation of China(Nos.12027809,11961141003,U1967201,11875073 and 11875074).
文摘A digital data-acquisition system based on XIA LLC products was used in a complex nuclear reaction experiment using radioactive ion beams.A flexible trigger system based on a field-programmable gate array(FPGA)parametrization was developed to adapt to different experimental sizes.A user-friendly interface was implemented,which allows converting script language expressions into FPGA internal control parameters.The proposed digital system can be combined with a conventional analog data acquisition system to provide more flexibility.The performance of the combined system was veri-fied using experimental data.
基金National Natural Science Foundation of China,No.42101259,No.42371101,No.42301455Qin Chuangyuan Cites High-level Innovation or Entrepreneurship Talent Project,No.QCYRCXM-2023-066+2 种基金Fifth Batch Special Funding(Pre-Station)from China Postdoctoral Science Foundation,No.2023TQ0207Fundamental Research Funds for the Central Universities,No.GK202304024,No.1110011297,No.1112010355Teaching Reform Project of Shaanxi University,No.23GGYS-JG06。
文摘The area of land that is affected by soil erosion in the Yangtze River has been reduced by 146,000 km~2(accounting for 27%of the entire Yangtze River)since 2000.However,the contributions of different tributaries to this soil erosion decline and the underlying causes have not been determined.Here we quantify the soil erosion decline in the Yangtze River and the impacts of the Grain-for-Green Programme(GFGP)and climate change using the RUSLE model and statistical methods.The results were as follows:(1)After the implementation of the GFGP,soil erosion decreased in ten sub-basins excluding the Dongting Lake catchment;(2)Soil erosion was mainly affected by the GFGP and the rainfall erosivity.Specifically,the contributions of the GFGP and rainfall erosivity to soil erosion decline are estimated to be 70.12%and 29.88%,respectively.(3)“Scenario#9”means the combination of slope(15°-25°)of retired farmland converted to shrub land and slope(>25°)of retired farmland converted to grassland.Considering scenario feasibility and management targets,Scenario#9 was the most appropriate land use scenario for the Yangtze River.This study offers insights into managing and reducing soil erosion in the future.
基金financial support from the National Natural Science Foundation of China(Nos.62104017 and 52072204)Beijing Institute of Technology Research Fund Program for Young Scholars.
文摘Manipulating the expression of synaptic plasticity of neuromorphic devices provides fascinating opportunities to develop hardware platforms for artifi-cial intelligence.However,great efforts have been devoted to exploring biomimetic mechanisms of plasticity simulation in the last few years.Recent progress in various plasticity modulation techniques has pushed the research of synaptic electronics from static plasticity simulation to dynamic plasticity modulation,improving the accuracy of neuromorphic computing and providing strategies for implementing neuromorphic sensing functions.Herein,several fascinating strategies for synap-tic plasticity modulation through chemical techniques,device structure design,and physical signal sensing are reviewed.For chemical techniques,the underly-ing mechanisms for the modification of functional materials were clarified and its effect on the expression of synaptic plasticity was also highlighted.Based on device structure design,the reconfigurable operation of neuromorphic devices was well demonstrated to achieve programmable neuromorphic functions.Besides,integrating the sensory units with neuromorphic processing circuits paved a new way to achieve human-like intelligent perception under the modulation of physical signals such as light,strain,and temperature.Finally,considering that the relevant technology is still in the basic exploration stage,some prospects or development suggestions are put forward to promote the development of neuromorphic devices.
基金supported by National Natural Science Foundation of China(Grant nos.52275290,51905222)Natural Science Foundation of Jiangsu Province(Grant no.BK20211068)+2 种基金Research Project of State Key Laboratory of Mechanical System and Vibration(Grant no.MSV202419)Major Program of National Natural Science Foundation of China(NSFC)for Basic Theory and Key Technology of Tri-Co Robots(Grant no.92248301)Opening project of the Key Laboratory of Bionic Engineering(Ministry of Education),Jilin University(Grant no.KF2023006).
文摘Inspired by the way sea turtles rely on the Earth’s magnetic field for navigation and locomotion,a novel magnetic soft robotic turtle with programmable magnetization has been developed and investigated to achieve biomimetic locomotion patterns such as straight-line swimming and turning swimming.The soft robotic turtle(12.50 mm in length and 0.24 g in weight)is integrated with an Ecoflex-based torso and four magnetically programmed acrylic elastomer VHB-based limbs containing samarium-iron–nitrogen particles,and was able to carry a load more than twice its own weight.Similar to the limb locomotion characteristics of sea turtles,the magnetic torque causes the four limbs to mimic sinusoidal bending deformation under the influence of an external magnetic field,so that the turtle swims continuously forward.Significantly,when the bending deformation magnitudes of its left and right limbs differ,the soft robotic turtle switches from straight-line to turning swimming at 6.334 rad/s.Furthermore,the tracking swimming activities of the soft robotic turtle along specific planned paths,such as square-shaped,S-shaped,and double U-shaped maze,is anticipated to be utilized for special detection and targeted drug delivery,among other applications owing to its superior remote directional control ability.
