In terms of fast response problem of unanticipated marine target, it is necessary to design the satellite-ground-combined operation mechanism and planning algorithm for autonomous task planning. Firstly, based on the ...In terms of fast response problem of unanticipated marine target, it is necessary to design the satellite-ground-combined operation mechanism and planning algorithm for autonomous task planning. Firstly, based on the autonomous operation and task planning of remote sensing satellite group, it is divided into two parts: ground planning and satellite autonomous planning. Secondly,the satellite-ground-combined operation mechanism and operation flow for task planning are proposed after fully considering the resource characteristics and task demand characteristics of the ground and satellite. The satellite autonomous task planning algorithm based on extended contract net is designed. Through the simulation operation of the self-developed distributed simulation demonstration software, it shows that the operation mechanism can coordinate and cooperate effectively between the satellite autonomous task planning and ground planning. It can give full play to the advantages of the ground computing resources, reflect the control intention, make full use of the real-time feature and flexibility of the satellite calculation, and respond fast to the unanticipated task. Besides, it has solved problems of the untimely response of ground control on unanticipated observation task, the limitation of satellite computing resources and satellite-ground planning and coordination, which can effectively improve the responsiveness of remote sensing satellite to the observation task of maritime unanticipated target.展开更多
If there are a lot of inputs,the readability of the “If-then” fuzzy rule is reduced,and the complexity of the fuzzy neural network structure will be increased.Hence,to optimize the structure of the fuzzy rule based ...If there are a lot of inputs,the readability of the “If-then” fuzzy rule is reduced,and the complexity of the fuzzy neural network structure will be increased.Hence,to optimize the structure of the fuzzy rule based neural network,a group Lasso based redundancy-controlled feature selection(input pruning) method is proposed.For realizing feature selection,the linear/nonlinear redundancy between features is considered,and the Pearson’s correlation coefficient is employed to construct the additive redundancy-controlled regularizer in the error function.In addition,considering the past gradient information,a novel parameter optimization method is presented.Finally,we demonstrate the effectiveness of our method on two benchmark classification datasets.展开更多
The use of groups of unmanned aerial vehicles（UAVs） has greatly expanded UAV＇s capabilities in a variety of applications, such as surveillance, searching and mapping. As the UAVs are operated as a team, it is impor...The use of groups of unmanned aerial vehicles（UAVs） has greatly expanded UAV＇s capabilities in a variety of applications, such as surveillance, searching and mapping. As the UAVs are operated as a team, it is important to detect and isolate the occurrence of anomalous aircraft in order to avoid collisions and other risks that would affect the safety of the team. In this paper, we present a data-driven approach to detect and isolate abnormal aircraft within a team of formatted flying aerial vehicles, which removes the requirements for the prior knowledge of the underlying dynamic model in conventional model-based fault detection algorithms. Based on the assumption that normal behaviored UAVs should share similar（dynamic） model parameters, we propose to firstly identify the model parameters for each aircraft of the team based on a sequence of input and output data pairs, and this is achieved by a novel sparse optimization technique. The fault states of the UAVs would be detected and isolated in the second step by identifying the change of model parameters.Simulation results have demonstrated the efficiency and flexibility of the proposed approach.展开更多
This article introduces a novel 20 V radiation-hardened high-voltage metal-oxide-semiconductor field-effect transistor(MOSFET)driver with an optimized input circuit and a drain-surrounding-source(DSS)structure.The inp...This article introduces a novel 20 V radiation-hardened high-voltage metal-oxide-semiconductor field-effect transistor(MOSFET)driver with an optimized input circuit and a drain-surrounding-source(DSS)structure.The input circuit of a conventional inverter consists of a thick-gate-oxide n-type MOSFET(NMOS).These conventional drivers can tolerate a total ionizing dose(TID)of up to 100 krad(Si).In contrast,the proposed comparator input circuit uses both a thick-gate-oxide p-type MOSFET(PMOS)and thin-gate-oxide NMOS to offer a high input voltage and higher TID tolerance.Because the thick-gate-oxide PMOS and thin-gate-oxide NMOS collectively provide better TID tolerance than the thick-gate-oxide NMOS,the circuit exhibits enhanced TID tolerance of>300 krad(Si).Simulations and experimental date indicate that the DSS structure reduces the probability of unwanted parasitic bipolar junction transistor activation,yielding a better single-event effect tolerance of over 81.8 MeVcm^(2)mg^(-1).The innovative strategy proposed in this study involves circuit and layout design optimization,and does not require any specialized process flow.Hence,the proposed circuit can be manufactured using common commercial 0.35μm BCD processes.展开更多
We investigate theoretically the enhancement of mechanical squeezing in a multimode optomechanical system by introducing a coherent phonon–photon interaction via the backward stimulated Brillouin scattering(BSBS)proc...We investigate theoretically the enhancement of mechanical squeezing in a multimode optomechanical system by introducing a coherent phonon–photon interaction via the backward stimulated Brillouin scattering(BSBS)process.The coherent photon–phonon interaction where two optical modes couple to a Brillouin acoustic mode with a large decay rate provides an extra channel for the cooling of a Duffing mechanical oscillator.The squeezing degree and the robustness to the thermal noises of the Duffing mechanical mode can be enhanced greatly.When the Duffing nonlinearity is weak,the squeezing degree of the mechanical mode in the presence of BSBS can be improved by more than one order of magnitude compared with that in the absence of BSBS.Our scheme may be extended to other quantum systems to study novel quantum effects.展开更多
Nowadays,force sensors play an important role in industrial production,electronic information,medical health,and many other fields.Two-dimensional material-based filed effect transistor(2D-FET)sensors are competitive ...Nowadays,force sensors play an important role in industrial production,electronic information,medical health,and many other fields.Two-dimensional material-based filed effect transistor(2D-FET)sensors are competitive with nano-level size,lower power consumption,and accurate response.However,few of them has the capability of impulse detection which is a path function,expressing the cumulative effect of the force on the particle over a period of time.Herein we fabricated the flexible polymethyl methacrylate(PMMA)gate dielectric MoS_(2)-FET for force and impulse sensor application.We systematically investigated the responses of the sensor to constant force and varying forces,and achieved the conversion factors of the drain current signals(I_(ds))to the detected impulse(I).The applied force was detected and recorded by I_(ds)with a low power consumption of~30 nW.The sensitivity of the device can reach~8000%and the 4×1 sensor array is able to detect and locate the normal force applied on it.Moreover,there was almost no performance loss for the device as left in the air for two months.展开更多
Existing Chinese named entity recognition(NER)research utilises 1D lexicon-based sequence labelling frameworks,which can only recognise flat entities.While lexicons serve as prior knowledge and enhance semantic inform...Existing Chinese named entity recognition(NER)research utilises 1D lexicon-based sequence labelling frameworks,which can only recognise flat entities.While lexicons serve as prior knowledge and enhance semantic information,they also pose completeness and resource requirements limitations.This paper proposes a template-based classification(TC)model to avoid lexicon issues and to identify nested entities.Template-based classification provides a template word for each entity type,which utilises contrastive learning to integrate the common characteristics among entities with the same category.Contrastive learning makes template words the centre points of their category in the vector space,thus improving generalisation ability.Additionally,TC presents a 2D tablefilling label scheme that classifies entities based on the attention distribution of template words.The proposed novel decoder algorithm enables TC recognition of both flat and nested entities simultaneously.Experimental results show that TC achieves the state-ofthe-art performance on five Chinese datasets.展开更多
This paper proposed an efficient method of image overlapping relationship analysis based on spatial index of KD tree fast search for disordered and large-scale asteroid images.In this study,the image data from asteroi...This paper proposed an efficient method of image overlapping relationship analysis based on spatial index of KD tree fast search for disordered and large-scale asteroid images.In this study,the image data from asteroid exploration missions such as Bennu,Vesta,and Ryugu were used for experiments,and the proposed image matching pairs determination algorithm was comprehensively compared with the corresponding modules of USGS ISIS in order to evaluate its performance in terms of efficiency and accuracy.The results show that when processing more than a thousand images,the proposed method greatly improves the efficiency of acquiring image matching pairs while ensuring the correctness of image overlapping relationships and accuracy of bundle adjustment.At the same time,according to the obtained image matching pairs,images that meet the requirements of Stereo Photoclinometry can be quickly selected,effectively improving the quality of 3D reconstruction models of asteroid images.展开更多
This paper focuses on AI intelligence as the fundamental direction to conduct research on information system operation and maintenance(O&M).Combining current AI-supported technologies in information system O&M...This paper focuses on AI intelligence as the fundamental direction to conduct research on information system operation and maintenance(O&M).Combining current AI-supported technologies in information system O&M,it proposes O&M strategies such as intelligent fault prediction and diagnosis,intelligent system performance optimization,intelligent system security protection,and adaptive system O&M implementation.Practical applications reveal that AI intelligence technology offers significant advantages in information system O&M,effectively addressing pain points of traditional O&M techniques,such as low fault prediction rates,slow repair speeds,poor security interception,and high labor costs.This substantially enhances the effectiveness of information system O&M.展开更多
With the rapid development of information technology,data security issues have received increasing attention.Data encryption and decryption technology,as a key means of ensuring data security,plays an important role i...With the rapid development of information technology,data security issues have received increasing attention.Data encryption and decryption technology,as a key means of ensuring data security,plays an important role in multiple fields such as communication security,data storage,and data recovery.This article explores the fundamental principles and interrelationships of data encryption and decryption,examines the strengths,weaknesses,and applicability of symmetric,asymmetric,and hybrid encryption algorithms,and introduces key application scenarios for data encryption and decryption technology.It examines the challenges and corresponding countermeasures related to encryption algorithm security,key management,and encryption-decryption performance.Finally,it analyzes the development trends and future prospects of data encryption and decryption technology.This article provides a systematic understanding of data encryption and decryption techniques,which has good reference value for software designers.展开更多
In the process of power scaling large-area Quantum Cascade Lasers(QCLs),challenges such as degradation of beam quality and emission of multilobed far-field modes are frequently encountered.These issues become particul...In the process of power scaling large-area Quantum Cascade Lasers(QCLs),challenges such as degradation of beam quality and emission of multilobed far-field modes are frequently encountered.These issues become particularly pronounced with an increase in ridge width,resulting in multimode problems.To tackle this,an innovative multi ridge waveguide structure based on the principle of supersymmetry(SUSY)was proposed.This structure comprises a wider main waveguide in the center and two narrower auxiliary waveguides on either side.The high-order modes of the main waveguide are coupled with the modes of the auxiliary waveguides through mode-matching design,and the optical loss of the auxiliary waveguides suppresses these modes,thereby achieving fundamental mode lasing of the wider main waveguide.This paper employs the finite difference eigenmode(FDE)method to perform detailed structural modeling and simulation optimization of the 4.6μm wavelength quantum cascade laser,successfully achieving a single transverse mode QCL with a ridge width of 10μm.In comparison to the traditional single-mode QCL(with a ridge width of about 5μm),the MRW structure has the potential to increase the gain area of the laser by 100%.This offers a novel design concept and methodology for enhancing the single-mode luminous power of mid-infrared quantum cascade lasers,which is of considerable significance.展开更多
Soft magnetic composites made from metallic magnetic particles with an easy magnetization plane(referred to as easy-plane metallic soft magnetic composites(SMC))are considered ideal materials for the next generation o...Soft magnetic composites made from metallic magnetic particles with an easy magnetization plane(referred to as easy-plane metallic soft magnetic composites(SMC))are considered ideal materials for the next generation of power electronic devices.This advantage is attributed to their ability to maintain high permeability at elevated frequencies.Despite these advantages,a definitive mathematical model that connects the high-frequency magnetic properties(e.g.,effective permeability)of easy-plane metallic SMCs to the intrinsic properties of the particles is still lacking.In this work,a theoretical calculation model for the effective permeability of easy-plane metallic SMCs was formulated.This model was derived from a skin effect-corrected Landau-Lifshitz-Gilbert(LLG)equation and integrated with effective medium theory incorporating inter-particle interaction.To validate the model,we prepared samples of easy-plane Y_(2)Co_(17)particle/PU SMCs with varying particle sizes and volume fractions.The experimental results showed a strong agreement with the calculated values.This research offers critical theoretical backing for the design and optimization of soft magnetic materials intended for high-frequency applications.展开更多
As key technologies in 6G,Space-Air-Ground Integrated Networks(SAGIN)promises to provide seamless global coverage through a comprehensive,ubiquitous communication system,while Integrated Sensing and Communications(ISA...As key technologies in 6G,Space-Air-Ground Integrated Networks(SAGIN)promises to provide seamless global coverage through a comprehensive,ubiquitous communication system,while Integrated Sensing and Communications(ISAC)effectively addresses spectrum congestion by sharing spectrum resources and transceivers for simultaneous communication and sensing operations.However,existing ISAC research has primarily focused on terrestrial networks,with limited exploration of its applications in SAGIN environments.This paper proposes a novel SAGIN-ISAC scheme leveraging High-Altitude Platform Stations(HAPS).In this scheme,HAPS serves as a relay node that not only amplifies and forwards communication signals but also receives and processes target echo signals for parameter estimation.The satellite employs Resilient Massive Access(RMA)to provide communication services to different User Terminals(UTs).To address scenarios with an unknown number of targets,we develop a Two-threshold Detection and Parameter Multiple Signal Classification(MUSIC)algorithm(TDPM),which employs dual-threshold correlation detection to determine the number of targets and utilizes the MUSIC algorithm to estimate targets’Angle of Arrival(AoA),range,and relative velocity.Furthermore,we establish a joint optimization framework that considers both communication and sensing performance,optimizing energy efficiency,detection probability,and the Cramér-Rao bound.The power allocation coefficients are derived through Nash equilibrium,while the precoding matrix is optimized using Sequential Convex Approximation(SCA)to address the non-convex nature of the optimization problem.Experimental results demonstrate that our proposed scheme significantly enhances the overall performance of the SAGIN-ISAC system.展开更多
The continuously available satellites of European Galileo currently reach more than 25.To explore the rationality and reliability of the L-band and satellite laser ranging(SLR)data processing strategies,we design the ...The continuously available satellites of European Galileo currently reach more than 25.To explore the rationality and reliability of the L-band and satellite laser ranging(SLR)data processing strategies,we design the Galileo L-band,the SLR-only,and the combined L-band/SLR dynamic precise orbit determination(POD)strategies by using the normal equations(NEQs)stacking,and investigate their continuity and stability by employing the Galileo L-band data and SLR observations for the time span of the whole year of 2023,based on the Bei Dou/GNSS analysis center platform of Shandong University by using the modified Bernese GNSS Software Version 5.4.The orbital consistency of the L-band 1-day solution is the best with the Three-dimensional Root-Mean-Square(3D-RMS)values of 3.6 cm compared with the Center for Orbit Determination in Europe Multi-GNSS Experiment(COM)orbits,the corresponding values is 1.4 cm,2.5 cm,and 2.3 cm in Radial,the Tangential,and the Normal(RTN)direction,respectively.While the SLR-only 9-day arc length is optimal with the RTN values of 5.3 cm,30 cm,and 38.2 cm,as well as the 3D-RMS values of 48.9 cm.Encouragingly,the difference of the orbital accuracy between the combined L-band/SLR multi-day solution and the COM orbits is reduced by 0.5 cm and 0.9 cm,0.6 cm and 1.2 cm in T-,and N-direction for the 3-and 5-day solution respectively.The corresponding values improve 0.7 cm and 0.9 cm,1.4 cm and 1.8 cm for the 3-and 5-day orbital overlaps difference between the combined L-band/SLR and the L-band solution.Take the E09 satellite as a case study,the SLR-only orbital accuracy is regularly optimized as the multi-day arc lengthens and with the sites increase.Furthermore,the SLR residuals of its three types of orbits further demonstrate the positive contribution of SLR to the combination of the GNSS and SLR techniques.展开更多
This paper is concerned with design-ing symbol labeling for a low-density parity-check(LDPC)-coded delayed bit-interleaved coded modu-lation(DBICM)scheme in a two-way relay channel(TWRC).We first present some properti...This paper is concerned with design-ing symbol labeling for a low-density parity-check(LDPC)-coded delayed bit-interleaved coded modu-lation(DBICM)scheme in a two-way relay channel(TWRC).We first present some properties of symbol labeling within a phase shift keying(PSK)modula-tion.These properties reduce the candidate labeling search space.Based on this search space,we take DBICM capacity as the cost function and propose a general method for optimizing symbol labeling by em-ploying the differential evolution algorithm.Numeri-cal results show that our labeling obtains a signal-to-noise ratio(SNR)gain up to 0.45 dB with respect to Gray labeling.展开更多
The collective dynamic of a fractional-order globally coupled system with time delays and fluctuating frequency is investigated.The power-law memory of the system is characterized using the Caputo fractional derivativ...The collective dynamic of a fractional-order globally coupled system with time delays and fluctuating frequency is investigated.The power-law memory of the system is characterized using the Caputo fractional derivative operator.Additionally,time delays in the potential field force and coupling force transmission are both considered.Firstly,based on the delay decoupling formula,combined with statistical mean method and the fractional-order Shapiro–Loginov formula,the“statistic synchronization”among particles is obtained,revealing the statistical equivalence between the mean field behavior of the system and the behavior of individual particles.Due to the existence of the coupling delay,the impact of the coupling force on synchronization exhibits non-monotonic,which is different from the previous monotonic effects.Then,two kinds of theoretical expression of output amplitude gains G and G are derived by time-delay decoupling formula and small delay approximation theorem,respectively.Compared to G,G is an exact theoretical solution,which means that G is not only more accurate in the region of small delay,but also applies to the region of large delay.Finally,the study of the output amplitude gain G and its resonance behavior are explored.Due to the presence of the potential field delay,a new resonance phenomenon termed“periodic resonance”is discovered,which arises from the periodic matching between the potential field delay and the driving frequency.This resonance phenomenon is analyzed qualitatively and quantitatively,uncovering undiscovered characteristics in previous studies.展开更多
This paper investigates how to achieve integrated sensing and communication(ISAC)based on a cell-free radio access network(CF-RAN)architecture with a minimum footprint of communication resources.We propose a new passi...This paper investigates how to achieve integrated sensing and communication(ISAC)based on a cell-free radio access network(CF-RAN)architecture with a minimum footprint of communication resources.We propose a new passive sensing scheme.The scheme is based on the radio frequency(RF)fingerprint learning of the RF radio unit(RRU)to build an RF fingerprint library of RRUs.The source RRU is identified by comparing the RF fingerprints carried by the signal at the receiver side.The receiver extracts the channel parameters from the signal and estimates the channel environment,thus locating the reflectors in the environment.The proposed scheme can effectively solve the problem of interference between signals in the same time-frequency domain but in different spatial domains when multiple RRUs jointly serve users in CF-RAN architecture.Simulation results show that the proposed passive ISAC scheme can effectively detect reflector location information in the environment without degrading the communication performance.展开更多
This paper considers the swarm vigilance problem for multi-agent systems(MAS),where multiple agents are deployed within a rectangular region for perception-based vigilance.There are two main challenges,namely the task...This paper considers the swarm vigilance problem for multi-agent systems(MAS),where multiple agents are deployed within a rectangular region for perception-based vigilance.There are two main challenges,namely the task allocation for vigilance roles and the coverage planning of the perception ranges.Firstly,vigilance behavioral patterns and processes in animal populations within natural habitats are investigated.Inspired by these biological vigilance behaviors,an efficient vigilance task allocation model for MAS is proposed.Secondly,the subsequent optimization of task layouts can achieve efficient surveillance coverage with fewer agents,minimizing resource consumption.Thirdly,an improved particle swarm optimization(IPSO)algorithm is proposed,which incorporates fitness-driven adaptive inertia weight dynamics.According to simulation analysis and comparative studies,optimal parameter configurations for genetic algorithm(GA)and IPSO are determined.Finally,the results indicate the proposed IPSO's superior performance to both GA and standard particle swarm optimization(PSO)in vigilance task allocation optimization,with satisfying advantages in computational efficiency and solution quality.展开更多
Radio antenna arrays have many advantages for astronomical observations,such as high resolution,high sensitivity,multi-target simultaneous observation,and flexible beam formation.Problems surrounding key indices,such ...Radio antenna arrays have many advantages for astronomical observations,such as high resolution,high sensitivity,multi-target simultaneous observation,and flexible beam formation.Problems surrounding key indices,such as sensitivity enhancement,scanning range extension,and sidelobe level suppression,need to be solved urgently.Here,we propose a sparse optimization scheme based on a genetic algorithm for a 64-array element planar radio antenna array.As optimization targets for the iterative process of the genetic algorithm,we use the maximum sidelobe levels and beamwidth of multiple cross-section patterns that pass through the main beam in three-dimensions,with the maximum sidelobe levels of the patterns at several different scanning angles.Element positions are adjusted for iterations,to select the optimal array configuration.Following sparse layout optimization,the simulated 64-element planar radio antenna array shows that the maximum sidelobe level decreases by 1.79 dB,and the beamwidth narrows by 3°.Within the scan range of±30°,after sparse array optimization,all sidelobe levels decrease,and all beamwidths narrow.This performance improvement can potentially enhance the sensitivity and spatial resolution of radio telescope systems.展开更多
By focusing on the nonlinear bending behavior of functionally graded carbon nanotube-reinforced(FG-CNTR)curved nanobeams under thermal loads while considering size effects,this paper fills the apparent void by compreh...By focusing on the nonlinear bending behavior of functionally graded carbon nanotube-reinforced(FG-CNTR)curved nanobeams under thermal loads while considering size effects,this paper fills the apparent void by comprehensively incorporating the Chen-Yao surface elasticity theory and modified couple-stress theory.A tri-parameter elastic substrate model is introduced,and the temperature dependence of material properties is considered.Through a two-step perturbation technique,the asymptotic solutions for the temperature-deflection relationship are obtained.After that,novel numerical results are provided to explore the impacts of temperature,size effects,geometric characteristics of the curved beams,elastic substrates,properties of the CNT reinforcements,and boundary conditions.The results indicate that surface effects,couple stress effects,and the elastic foundation enhance the bending stiffness of FG-CNTR curved nanobeams.By considering both size effect theories,this study provides a more comprehensive and precise description of the nonlinear bending of FG-CNTR curved nanobeams under thermal loads.展开更多
基金co-supported by the Open Fund of CETC Key Laboratory of Aerospace Information Applications of China (No.EX166290023)the Open Fund of National Defense Key Disciplines Laboratory of Deep Space Exploration Landing and Return Control Technology of China (No.HIT.KLOF.2016.077)
文摘In terms of fast response problem of unanticipated marine target, it is necessary to design the satellite-ground-combined operation mechanism and planning algorithm for autonomous task planning. Firstly, based on the autonomous operation and task planning of remote sensing satellite group, it is divided into two parts: ground planning and satellite autonomous planning. Secondly,the satellite-ground-combined operation mechanism and operation flow for task planning are proposed after fully considering the resource characteristics and task demand characteristics of the ground and satellite. The satellite autonomous task planning algorithm based on extended contract net is designed. Through the simulation operation of the self-developed distributed simulation demonstration software, it shows that the operation mechanism can coordinate and cooperate effectively between the satellite autonomous task planning and ground planning. It can give full play to the advantages of the ground computing resources, reflect the control intention, make full use of the real-time feature and flexibility of the satellite calculation, and respond fast to the unanticipated task. Besides, it has solved problems of the untimely response of ground control on unanticipated observation task, the limitation of satellite computing resources and satellite-ground planning and coordination, which can effectively improve the responsiveness of remote sensing satellite to the observation task of maritime unanticipated target.
基金supported by the Major Project of National Natural Science Foundation of China (No.U19B2019)。
文摘If there are a lot of inputs,the readability of the “If-then” fuzzy rule is reduced,and the complexity of the fuzzy neural network structure will be increased.Hence,to optimize the structure of the fuzzy rule based neural network,a group Lasso based redundancy-controlled feature selection(input pruning) method is proposed.For realizing feature selection,the linear/nonlinear redundancy between features is considered,and the Pearson’s correlation coefficient is employed to construct the additive redundancy-controlled regularizer in the error function.In addition,considering the past gradient information,a novel parameter optimization method is presented.Finally,we demonstrate the effectiveness of our method on two benchmark classification datasets.
基金supported by Fundamental Research Funds for Central Universities of China(No.NS2014090)
文摘The use of groups of unmanned aerial vehicles（UAVs） has greatly expanded UAV＇s capabilities in a variety of applications, such as surveillance, searching and mapping. As the UAVs are operated as a team, it is important to detect and isolate the occurrence of anomalous aircraft in order to avoid collisions and other risks that would affect the safety of the team. In this paper, we present a data-driven approach to detect and isolate abnormal aircraft within a team of formatted flying aerial vehicles, which removes the requirements for the prior knowledge of the underlying dynamic model in conventional model-based fault detection algorithms. Based on the assumption that normal behaviored UAVs should share similar（dynamic） model parameters, we propose to firstly identify the model parameters for each aircraft of the team based on a sequence of input and output data pairs, and this is achieved by a novel sparse optimization technique. The fault states of the UAVs would be detected and isolated in the second step by identifying the change of model parameters.Simulation results have demonstrated the efficiency and flexibility of the proposed approach.
基金supported by the National Natural Science Foundation of China(U2241221).
文摘This article introduces a novel 20 V radiation-hardened high-voltage metal-oxide-semiconductor field-effect transistor(MOSFET)driver with an optimized input circuit and a drain-surrounding-source(DSS)structure.The input circuit of a conventional inverter consists of a thick-gate-oxide n-type MOSFET(NMOS).These conventional drivers can tolerate a total ionizing dose(TID)of up to 100 krad(Si).In contrast,the proposed comparator input circuit uses both a thick-gate-oxide p-type MOSFET(PMOS)and thin-gate-oxide NMOS to offer a high input voltage and higher TID tolerance.Because the thick-gate-oxide PMOS and thin-gate-oxide NMOS collectively provide better TID tolerance than the thick-gate-oxide NMOS,the circuit exhibits enhanced TID tolerance of>300 krad(Si).Simulations and experimental date indicate that the DSS structure reduces the probability of unwanted parasitic bipolar junction transistor activation,yielding a better single-event effect tolerance of over 81.8 MeVcm^(2)mg^(-1).The innovative strategy proposed in this study involves circuit and layout design optimization,and does not require any specialized process flow.Hence,the proposed circuit can be manufactured using common commercial 0.35μm BCD processes.
基金Project supported by the Scientific and Technological Research Program of Chongqing Municipal Education Commission(Grant No.KJQN202400624)the Natural Science Foundation of Chongqing CSTC(Grant No.CSTB2022NSCQBHX0020)+3 种基金the China Electronics Technology Group Corporation 44th Research Institute(Grant No.6310001-2)the Project Grant“Noninvasive Sensing Measurement based on Terahertz Technology”from Province and MOE Collaborative Innovation Centre for New Generation Information Networking and Terminalsthe Key Research Program of CQUPT on Interdisciplinary and Emerging Field(A2018-01)the Venture&Innovation Support program for Chongqing Overseas Returnees Year 2022。
文摘We investigate theoretically the enhancement of mechanical squeezing in a multimode optomechanical system by introducing a coherent phonon–photon interaction via the backward stimulated Brillouin scattering(BSBS)process.The coherent photon–phonon interaction where two optical modes couple to a Brillouin acoustic mode with a large decay rate provides an extra channel for the cooling of a Duffing mechanical oscillator.The squeezing degree and the robustness to the thermal noises of the Duffing mechanical mode can be enhanced greatly.When the Duffing nonlinearity is weak,the squeezing degree of the mechanical mode in the presence of BSBS can be improved by more than one order of magnitude compared with that in the absence of BSBS.Our scheme may be extended to other quantum systems to study novel quantum effects.
基金financially supported by the National Natural Science Foundation of China(Nos.52272160,U2330112,and 52002254)Sichuan Science and Technology Foundation(Nos.2020YJ0262,2021YFH0127,2022YFH0083,2022YFSY0045,and 2023YFSY0002)+1 种基金the Chunhui Plan of Ministry of Education,Fundamental Research Funds for the Central Universities,China(No.YJ201893)the Foundation of Key Laboratory of Lidar and Device,Sichuan Province,China(No.LLD2023-006)。
文摘Nowadays,force sensors play an important role in industrial production,electronic information,medical health,and many other fields.Two-dimensional material-based filed effect transistor(2D-FET)sensors are competitive with nano-level size,lower power consumption,and accurate response.However,few of them has the capability of impulse detection which is a path function,expressing the cumulative effect of the force on the particle over a period of time.Herein we fabricated the flexible polymethyl methacrylate(PMMA)gate dielectric MoS_(2)-FET for force and impulse sensor application.We systematically investigated the responses of the sensor to constant force and varying forces,and achieved the conversion factors of the drain current signals(I_(ds))to the detected impulse(I).The applied force was detected and recorded by I_(ds)with a low power consumption of~30 nW.The sensitivity of the device can reach~8000%and the 4×1 sensor array is able to detect and locate the normal force applied on it.Moreover,there was almost no performance loss for the device as left in the air for two months.
基金Sichuan Provincial Science and Technology Support Program,Grant/Award Number:2023YFG0151National Natural Science Foundation of China,Grant/Award Numbers:U22B2061,U2336204。
文摘Existing Chinese named entity recognition(NER)research utilises 1D lexicon-based sequence labelling frameworks,which can only recognise flat entities.While lexicons serve as prior knowledge and enhance semantic information,they also pose completeness and resource requirements limitations.This paper proposes a template-based classification(TC)model to avoid lexicon issues and to identify nested entities.Template-based classification provides a template word for each entity type,which utilises contrastive learning to integrate the common characteristics among entities with the same category.Contrastive learning makes template words the centre points of their category in the vector space,thus improving generalisation ability.Additionally,TC presents a 2D tablefilling label scheme that classifies entities based on the attention distribution of template words.The proposed novel decoder algorithm enables TC recognition of both flat and nested entities simultaneously.Experimental results show that TC achieves the state-ofthe-art performance on five Chinese datasets.
基金Space Optoelectronic Measurement and Perception Lab(LabSOMP-2023-07)the National Natural Science Foundation ofChina(42241147)+1 种基金the State Key Laboratory of Geo-Information Engineering(SKLGIE2021-Z-3-1)and the Open Program of Collaborativeinnovation Center of Geo-information(2023C002)。
文摘This paper proposed an efficient method of image overlapping relationship analysis based on spatial index of KD tree fast search for disordered and large-scale asteroid images.In this study,the image data from asteroid exploration missions such as Bennu,Vesta,and Ryugu were used for experiments,and the proposed image matching pairs determination algorithm was comprehensively compared with the corresponding modules of USGS ISIS in order to evaluate its performance in terms of efficiency and accuracy.The results show that when processing more than a thousand images,the proposed method greatly improves the efficiency of acquiring image matching pairs while ensuring the correctness of image overlapping relationships and accuracy of bundle adjustment.At the same time,according to the obtained image matching pairs,images that meet the requirements of Stereo Photoclinometry can be quickly selected,effectively improving the quality of 3D reconstruction models of asteroid images.
文摘This paper focuses on AI intelligence as the fundamental direction to conduct research on information system operation and maintenance(O&M).Combining current AI-supported technologies in information system O&M,it proposes O&M strategies such as intelligent fault prediction and diagnosis,intelligent system performance optimization,intelligent system security protection,and adaptive system O&M implementation.Practical applications reveal that AI intelligence technology offers significant advantages in information system O&M,effectively addressing pain points of traditional O&M techniques,such as low fault prediction rates,slow repair speeds,poor security interception,and high labor costs.This substantially enhances the effectiveness of information system O&M.
文摘With the rapid development of information technology,data security issues have received increasing attention.Data encryption and decryption technology,as a key means of ensuring data security,plays an important role in multiple fields such as communication security,data storage,and data recovery.This article explores the fundamental principles and interrelationships of data encryption and decryption,examines the strengths,weaknesses,and applicability of symmetric,asymmetric,and hybrid encryption algorithms,and introduces key application scenarios for data encryption and decryption technology.It examines the challenges and corresponding countermeasures related to encryption algorithm security,key management,and encryption-decryption performance.Finally,it analyzes the development trends and future prospects of data encryption and decryption technology.This article provides a systematic understanding of data encryption and decryption techniques,which has good reference value for software designers.
基金Supported by the National Natural Science Foundation of China(62105039)。
文摘In the process of power scaling large-area Quantum Cascade Lasers(QCLs),challenges such as degradation of beam quality and emission of multilobed far-field modes are frequently encountered.These issues become particularly pronounced with an increase in ridge width,resulting in multimode problems.To tackle this,an innovative multi ridge waveguide structure based on the principle of supersymmetry(SUSY)was proposed.This structure comprises a wider main waveguide in the center and two narrower auxiliary waveguides on either side.The high-order modes of the main waveguide are coupled with the modes of the auxiliary waveguides through mode-matching design,and the optical loss of the auxiliary waveguides suppresses these modes,thereby achieving fundamental mode lasing of the wider main waveguide.This paper employs the finite difference eigenmode(FDE)method to perform detailed structural modeling and simulation optimization of the 4.6μm wavelength quantum cascade laser,successfully achieving a single transverse mode QCL with a ridge width of 10μm.In comparison to the traditional single-mode QCL(with a ridge width of about 5μm),the MRW structure has the potential to increase the gain area of the laser by 100%.This offers a novel design concept and methodology for enhancing the single-mode luminous power of mid-infrared quantum cascade lasers,which is of considerable significance.
基金supported by the National Key R&D Program of China(Grant No.2021YFB3501300)the 9th Research Institute of China Electronics Technology Group Corporation’s open projects(Grant No.2024SK-002-01)the Science and Technology Project of Gansu Province(Grant No.22YF7GA001).
文摘Soft magnetic composites made from metallic magnetic particles with an easy magnetization plane(referred to as easy-plane metallic soft magnetic composites(SMC))are considered ideal materials for the next generation of power electronic devices.This advantage is attributed to their ability to maintain high permeability at elevated frequencies.Despite these advantages,a definitive mathematical model that connects the high-frequency magnetic properties(e.g.,effective permeability)of easy-plane metallic SMCs to the intrinsic properties of the particles is still lacking.In this work,a theoretical calculation model for the effective permeability of easy-plane metallic SMCs was formulated.This model was derived from a skin effect-corrected Landau-Lifshitz-Gilbert(LLG)equation and integrated with effective medium theory incorporating inter-particle interaction.To validate the model,we prepared samples of easy-plane Y_(2)Co_(17)particle/PU SMCs with varying particle sizes and volume fractions.The experimental results showed a strong agreement with the calculated values.This research offers critical theoretical backing for the design and optimization of soft magnetic materials intended for high-frequency applications.
基金supported in part by the Natural Science Foundation of Chongqing under Grant CSTB2023NSCQ-LZX0118in part by the National Natural Science Foundation of China under Grant 62471052in part by the Beijing University of Posts and Telecommunications(BUPT)Excellent Ph.D.Students Foundation under Grant CX2023139.
文摘As key technologies in 6G,Space-Air-Ground Integrated Networks(SAGIN)promises to provide seamless global coverage through a comprehensive,ubiquitous communication system,while Integrated Sensing and Communications(ISAC)effectively addresses spectrum congestion by sharing spectrum resources and transceivers for simultaneous communication and sensing operations.However,existing ISAC research has primarily focused on terrestrial networks,with limited exploration of its applications in SAGIN environments.This paper proposes a novel SAGIN-ISAC scheme leveraging High-Altitude Platform Stations(HAPS).In this scheme,HAPS serves as a relay node that not only amplifies and forwards communication signals but also receives and processes target echo signals for parameter estimation.The satellite employs Resilient Massive Access(RMA)to provide communication services to different User Terminals(UTs).To address scenarios with an unknown number of targets,we develop a Two-threshold Detection and Parameter Multiple Signal Classification(MUSIC)algorithm(TDPM),which employs dual-threshold correlation detection to determine the number of targets and utilizes the MUSIC algorithm to estimate targets’Angle of Arrival(AoA),range,and relative velocity.Furthermore,we establish a joint optimization framework that considers both communication and sensing performance,optimizing energy efficiency,detection probability,and the Cramér-Rao bound.The power allocation coefficients are derived through Nash equilibrium,while the precoding matrix is optimized using Sequential Convex Approximation(SCA)to address the non-convex nature of the optimization problem.Experimental results demonstrate that our proposed scheme significantly enhances the overall performance of the SAGIN-ISAC system.
基金under the support of the National Natural Science Foundation of China(Grant No.42388102),ChinaYouth Fund of the Natural Science Foundation of Hebei Province(Grant No.D2023523003),China。
文摘The continuously available satellites of European Galileo currently reach more than 25.To explore the rationality and reliability of the L-band and satellite laser ranging(SLR)data processing strategies,we design the Galileo L-band,the SLR-only,and the combined L-band/SLR dynamic precise orbit determination(POD)strategies by using the normal equations(NEQs)stacking,and investigate their continuity and stability by employing the Galileo L-band data and SLR observations for the time span of the whole year of 2023,based on the Bei Dou/GNSS analysis center platform of Shandong University by using the modified Bernese GNSS Software Version 5.4.The orbital consistency of the L-band 1-day solution is the best with the Three-dimensional Root-Mean-Square(3D-RMS)values of 3.6 cm compared with the Center for Orbit Determination in Europe Multi-GNSS Experiment(COM)orbits,the corresponding values is 1.4 cm,2.5 cm,and 2.3 cm in Radial,the Tangential,and the Normal(RTN)direction,respectively.While the SLR-only 9-day arc length is optimal with the RTN values of 5.3 cm,30 cm,and 38.2 cm,as well as the 3D-RMS values of 48.9 cm.Encouragingly,the difference of the orbital accuracy between the combined L-band/SLR multi-day solution and the COM orbits is reduced by 0.5 cm and 0.9 cm,0.6 cm and 1.2 cm in T-,and N-direction for the 3-and 5-day solution respectively.The corresponding values improve 0.7 cm and 0.9 cm,1.4 cm and 1.8 cm for the 3-and 5-day orbital overlaps difference between the combined L-band/SLR and the L-band solution.Take the E09 satellite as a case study,the SLR-only orbital accuracy is regularly optimized as the multi-day arc lengthens and with the sites increase.Furthermore,the SLR residuals of its three types of orbits further demonstrate the positive contribution of SLR to the combination of the GNSS and SLR techniques.
文摘This paper is concerned with design-ing symbol labeling for a low-density parity-check(LDPC)-coded delayed bit-interleaved coded modu-lation(DBICM)scheme in a two-way relay channel(TWRC).We first present some properties of symbol labeling within a phase shift keying(PSK)modula-tion.These properties reduce the candidate labeling search space.Based on this search space,we take DBICM capacity as the cost function and propose a general method for optimizing symbol labeling by em-ploying the differential evolution algorithm.Numeri-cal results show that our labeling obtains a signal-to-noise ratio(SNR)gain up to 0.45 dB with respect to Gray labeling.
基金supported by the Natural Science Foundation of Sichuan Province,China(Youth Science Foundation)(Grant No.2022NSFSC1952).
文摘The collective dynamic of a fractional-order globally coupled system with time delays and fluctuating frequency is investigated.The power-law memory of the system is characterized using the Caputo fractional derivative operator.Additionally,time delays in the potential field force and coupling force transmission are both considered.Firstly,based on the delay decoupling formula,combined with statistical mean method and the fractional-order Shapiro–Loginov formula,the“statistic synchronization”among particles is obtained,revealing the statistical equivalence between the mean field behavior of the system and the behavior of individual particles.Due to the existence of the coupling delay,the impact of the coupling force on synchronization exhibits non-monotonic,which is different from the previous monotonic effects.Then,two kinds of theoretical expression of output amplitude gains G and G are derived by time-delay decoupling formula and small delay approximation theorem,respectively.Compared to G,G is an exact theoretical solution,which means that G is not only more accurate in the region of small delay,but also applies to the region of large delay.Finally,the study of the output amplitude gain G and its resonance behavior are explored.Due to the presence of the potential field delay,a new resonance phenomenon termed“periodic resonance”is discovered,which arises from the periodic matching between the potential field delay and the driving frequency.This resonance phenomenon is analyzed qualitatively and quantitatively,uncovering undiscovered characteristics in previous studies.
基金supported in part by the National Key Research and Development Program under Grant(2021YFB2900300)by the National Natural Science Foundation of China(NSFC)under Grants 61971127,61871122by the Southeast University-China Mobile Research Institute Joint Innovation Center,and by the Major Key Project of PCL(PCL2021A01-2).
文摘This paper investigates how to achieve integrated sensing and communication(ISAC)based on a cell-free radio access network(CF-RAN)architecture with a minimum footprint of communication resources.We propose a new passive sensing scheme.The scheme is based on the radio frequency(RF)fingerprint learning of the RF radio unit(RRU)to build an RF fingerprint library of RRUs.The source RRU is identified by comparing the RF fingerprints carried by the signal at the receiver side.The receiver extracts the channel parameters from the signal and estimates the channel environment,thus locating the reflectors in the environment.The proposed scheme can effectively solve the problem of interference between signals in the same time-frequency domain but in different spatial domains when multiple RRUs jointly serve users in CF-RAN architecture.Simulation results show that the proposed passive ISAC scheme can effectively detect reflector location information in the environment without degrading the communication performance.
基金The National Natural Science Foundation of China(62203015,62233001,62273351)The Beijing Natural Science Foundation(4242038)。
文摘This paper considers the swarm vigilance problem for multi-agent systems(MAS),where multiple agents are deployed within a rectangular region for perception-based vigilance.There are two main challenges,namely the task allocation for vigilance roles and the coverage planning of the perception ranges.Firstly,vigilance behavioral patterns and processes in animal populations within natural habitats are investigated.Inspired by these biological vigilance behaviors,an efficient vigilance task allocation model for MAS is proposed.Secondly,the subsequent optimization of task layouts can achieve efficient surveillance coverage with fewer agents,minimizing resource consumption.Thirdly,an improved particle swarm optimization(IPSO)algorithm is proposed,which incorporates fitness-driven adaptive inertia weight dynamics.According to simulation analysis and comparative studies,optimal parameter configurations for genetic algorithm(GA)and IPSO are determined.Finally,the results indicate the proposed IPSO's superior performance to both GA and standard particle swarm optimization(PSO)in vigilance task allocation optimization,with satisfying advantages in computational efficiency and solution quality.
基金supported by the Ministry of Science and Technology SKA Special Project(2020SKA0110202)the Special Project on Building a Science and Technology Innovation Center for South and Southeast Asia–International Joint Innovation Platform in Yunnan Province:"Yunnan Sino-Malaysian International Joint Laboratory of HF-VHF Advanced Radio Astronomy Technology"(202303AP140003)+4 种基金the National Natural Science Foundation of China (NSFC) Joint Fund for Astronomy (JFA) incubator program (U2031133)the International Partnership Program Project of the International Cooperation Bureau of the Chinese Academy of Sciences:"Belt and Road"Cooperation (114A11KYSB20200001)the Kunming Foreign (International) Cooperation Base Program:"Yunnan Observatory of the Chinese Academy of Sciences-University of Malaya Joint R&D Cooperation Base for Advanced Radio Astronomy Technology"(GHJD-2021022)the China-Malaysia Collaborative Research on Space Remote Sensing and Radio Astronomy Observation of Space Weather at Low and Middle Latitudes under the Key Special Project of the State Key R&D Program of the Ministry of Science and Technology for International Cooperation in Science,Technology and Innovation among Governments (2022YFE0140000)the High-precision calibration method for low-frequency radio interferometric arrays for the SKA project of the Ministry of Science and Technology(2020SKA0110300).
文摘Radio antenna arrays have many advantages for astronomical observations,such as high resolution,high sensitivity,multi-target simultaneous observation,and flexible beam formation.Problems surrounding key indices,such as sensitivity enhancement,scanning range extension,and sidelobe level suppression,need to be solved urgently.Here,we propose a sparse optimization scheme based on a genetic algorithm for a 64-array element planar radio antenna array.As optimization targets for the iterative process of the genetic algorithm,we use the maximum sidelobe levels and beamwidth of multiple cross-section patterns that pass through the main beam in three-dimensions,with the maximum sidelobe levels of the patterns at several different scanning angles.Element positions are adjusted for iterations,to select the optimal array configuration.Following sparse layout optimization,the simulated 64-element planar radio antenna array shows that the maximum sidelobe level decreases by 1.79 dB,and the beamwidth narrows by 3°.Within the scan range of±30°,after sparse array optimization,all sidelobe levels decrease,and all beamwidths narrow.This performance improvement can potentially enhance the sensitivity and spatial resolution of radio telescope systems.
基金supports from the National Natural Science Foundation of China(12102085)the Postdoctoral Science Foundation of China(2023M730504)the Sichuan Province Regional Innovation and Cooperation Project(2024YFHZ0210).
文摘By focusing on the nonlinear bending behavior of functionally graded carbon nanotube-reinforced(FG-CNTR)curved nanobeams under thermal loads while considering size effects,this paper fills the apparent void by comprehensively incorporating the Chen-Yao surface elasticity theory and modified couple-stress theory.A tri-parameter elastic substrate model is introduced,and the temperature dependence of material properties is considered.Through a two-step perturbation technique,the asymptotic solutions for the temperature-deflection relationship are obtained.After that,novel numerical results are provided to explore the impacts of temperature,size effects,geometric characteristics of the curved beams,elastic substrates,properties of the CNT reinforcements,and boundary conditions.The results indicate that surface effects,couple stress effects,and the elastic foundation enhance the bending stiffness of FG-CNTR curved nanobeams.By considering both size effect theories,this study provides a more comprehensive and precise description of the nonlinear bending of FG-CNTR curved nanobeams under thermal loads.
