The paper addresses the decentralized optimal control and stabilization problems for interconnected systems subject to asymmetric information.Compared with previous work,a closed-loop optimal solution to the control p...The paper addresses the decentralized optimal control and stabilization problems for interconnected systems subject to asymmetric information.Compared with previous work,a closed-loop optimal solution to the control problem and sufficient and necessary conditions for the stabilization problem of the interconnected systems are given for the first time.The main challenge lies in three aspects:Firstly,the asymmetric information results in coupling between control and estimation and failure of the separation principle.Secondly,two extra unknown variables are generated by asymmetric information(different information filtration)when solving forward-backward stochastic difference equations.Thirdly,the existence of additive noise makes the study of mean-square boundedness an obstacle.The adopted technique is proving and assuming the linear form of controllers and establishing the equivalence between the two systems with and without additive noise.A dual-motor parallel drive system is presented to demonstrate the validity of the proposed algorithm.展开更多
The primary factor contributing to frequency instability in microgrids is the inherent intermittency of renewable energy sources.This paper introduces novel dual-backup controllers utilizing advanced fractional order ...The primary factor contributing to frequency instability in microgrids is the inherent intermittency of renewable energy sources.This paper introduces novel dual-backup controllers utilizing advanced fractional order proportional integral derivative(FOPID)controllers to enhance frequency and tie-line power stability in microgrids amid increasing renewable energy integration.To improve load frequency control,the proposed controllers are applied to a two-area interconnectedmicrogrid system incorporating diverse energy sources,such as wind turbines,photovoltaic cells,diesel generators,and various storage technologies.A novelmeta-heuristic algorithm is adopted to select the optimal parameters of the proposed controllers.The efficacy of the advanced FOPID controllers is demonstrated through comparative analyses against traditional proportional integral derivative(PID)and FOPID controllers,showcasing superior performance inmanaging systemfluctuations.The optimization algorithm is also evaluated against other artificial intelligent methods for parameter optimization,affirming the proposed solution’s efficiency.The robustness of the intelligent controllers against system uncertainties is further validated under extensive power disturbances,proving their capability to maintain grid stability.The dual-controller configuration ensures redundancy,allowing them to operate as mutual backups,enhancing system reliability.This research underlines the importance of sophisticated control strategies for future-proofing microgrid operations against the backdrop of evolving energy landscapes.展开更多
This paper presents an analysis of the power flow within the Northern Interconnected Grid of Cameroon. The Newton-Raphson method has been performed, known for its accuracy, under MATLAB software, to model and solve co...This paper presents an analysis of the power flow within the Northern Interconnected Grid of Cameroon. The Newton-Raphson method has been performed, known for its accuracy, under MATLAB software, to model and solve complex power flow equations. This study simulates a series of outage scenarios to evaluate the responsiveness of the grid. The results obtained underline the crucial importance of reactive power management and highlight the urgent need to consolidate the grid infrastructure of North Cameroon. To increase grid resilience and stability, the paper recommends the strategic integration of renewables and the development of interconnections with other power grids. These measures are presented as viable solutions to meet current and future energy distribution challenges, ensuring a reliable and sustainable power supply for Cameroon.展开更多
With the rapid development of network technologies,a large number of deployed edge devices and information systems generate massive amounts of data which provide good support for the advancement of data-driven intelli...With the rapid development of network technologies,a large number of deployed edge devices and information systems generate massive amounts of data which provide good support for the advancement of data-driven intelligent models.However,these data often contain sensitive information of users.Federated learning(FL),as a privacy preservation machine learning setting,allows users to obtain a well-trained model without sending the privacy-sensitive local data to the central server.Despite the promising prospect of FL,several significant research challenges need to be addressed before widespread deployment,including network resource allocation,model security,model convergence,etc.In this paper,we first provide a brief survey on some of these works that have been done on FL and discuss the motivations of the Communication Networks(CNs)and FL to mutually enable each other.We analyze the support of network technologies for FL,which requires frequent communication and emphasizes security,as well as the studies on the intelligence of many network scenarios and the improvement of network performance and security by the methods based on FL.At last,some challenges and broader perspectives are explored.展开更多
High-density interconnect(HDI)soft electronics that can integrate multiple individual functions into one miniaturized monolithic system is promising for applications related to smart healthcare,soft robotics,and human...High-density interconnect(HDI)soft electronics that can integrate multiple individual functions into one miniaturized monolithic system is promising for applications related to smart healthcare,soft robotics,and human-machine interactions.However,despite the recent advances,the development of three-dimensional(3D)soft electronics with both high resolution and high integration is still challenging because of the lack of efficient manufacturing methods to guarantee interlayer alignment of the high-density vias and reliable interlayer electrical conductivity.Here,an advanced 3D laser printing pathway,based on femtosecond laser direct writing(FLDW),is demonstrated for preparing liquid metal(LM)-based any layer HDI soft electronics.FLDW technology,with the characteristics of high spatial resolution and high precision,allows the maskless fabrication of high-resolution embedded LM microchannels and high-density vertical interconnect accesses for 3D integrated circuits.High-aspect-ratio blind/through LM microstructures are formed inside the elastomer due to the supermetalphobicity induced during laser ablation.The LM-based HDI circuit featuring high resolution(~1.5μm)and high integration(10-layer electrical interconnection)is achieved for customized soft electronics,including various customized multilayer passive electric components,soft multilayer circuit,and cross-scale multimode sensors.The 3D laser printing method provides a versatile approach for developing chip-level soft electronics.展开更多
Propelled by the rise of artificial intelligence,cloud services,and data center applications,next-generation,low-power,local-oscillator-less,digital signal processing(DSP)-free,and short-reach coherent optical communi...Propelled by the rise of artificial intelligence,cloud services,and data center applications,next-generation,low-power,local-oscillator-less,digital signal processing(DSP)-free,and short-reach coherent optical communication has evolved into an increasingly prominent area of research in recent years.Here,we demonstrate DSP-free coherent optical transmission by analog signal processing in frequency synchronous optical network(FSON)architecture,which supports polarization multiplexing and higher-order modulation formats.The FSON architecture that allows the numerous laser sources of optical transceivers within a data center can be quasi-synchronized by means of a tree-distributed homology architecture.In conjunction with our proposed pilot-tone assisted Costas loop for an analog coherent receiver,we achieve a record dual-polarization 224-Gb/s 16-QAM 5-km mismatch transmission with reset-free carrier phase recovery in the optical domain.Our proposed DSP-free analog coherent detection system based on the FSON makes it a promising solution for next-generation,low-power,and high-capacity coherent data center interconnects.展开更多
As the development of single-junction solar cells reaches a bottleneck,tandem solar cells have emerged as a critical pathway to further enhance power conversion efficiency.Among them,monolithic perovskite/silicon hete...As the development of single-junction solar cells reaches a bottleneck,tandem solar cells have emerged as a critical pathway to further enhance power conversion efficiency.Among them,monolithic perovskite/silicon heterojunction tandem solar cells are currently the fastest-growing technology,achieving the highest efficiencies at relatively low costs.The intercon-necting layer,which connects the two sub-cells,plays a crucial role in tandem cell performance.It collects electrons and holes from the respective sub-cells and facilitates recombination and tunneling at the interface.Therefore,the properties of the inter-connecting layer are pivotal to the overall device performance.In this work,we applied statistical analysis and machine learn-ing algorithms to systematically analyze the interconnecting layer.A comprehensive dataset on interconnecting layer parame-ters was established,and predictive modeling was performed using Lasso linear regression,random forest,and multilayer per-ceptron(a type of neural network).The analysis revealed key feature importance for experimental parameters,providing valu-able insights into the application of interconnecting layers in perovskite/silicon heterojunction tandem solar cells.The final opti-mized interconnecting layer can achieve a proof-of-concept efficiency of 38.17%,providing guidance and direction for the devel-opment of monolithic perovskite/silicon tandem solar cells.展开更多
Permanent Magnet Synchronous Motors(PMSMs)are widely employed in high-performance drive applications due to their superior efficiency and dynamic capabilities.However,their control remains challenging owing to nonline...Permanent Magnet Synchronous Motors(PMSMs)are widely employed in high-performance drive applications due to their superior efficiency and dynamic capabilities.However,their control remains challenging owing to nonlinear dynamics,parameter variations,and unmeasurable external disturbances,particularly load torquefluctuations.This study proposes an enhanced Interconnection and Damp-ing Assignment Passivity-Based Control(IDA-PBC)scheme,formulated within the port-controlled Hamiltonian(PCH)framework,to address these limitations.A nonlinear disturbance observer is embedded to estimate and compensate,in real time,for lumped mis-matched disturbances arising from parameter uncertainties and external loads.Additionally,aflatness-based control strategy is employed to generate the desired current references within the nonlinear drive system,ensuring accurate tracking of time-varying speed commands.This integrated approach preserves the system’s energy-based structure,enabling systematic stability analysis while enhancing robustness.The proposed control architecture also maintains low complexity with a limited number of tunable parameters,facilitating practical implementation.Simulation and experimental results under various operating conditions demonstrate the effectiveness and robustness of the proposed method.Comparative analysis with conventional proportional-integral(PI)control and standard IDA-PBC strategies confirms its capability to handle disturbances and maintain dynamic performance.展开更多
This study focused on meeting the stringent stability requirements of tubular segmented-in-series solid oxide fuel cells(SOFCs) in reducing and oxidizing atmospheres.To address this challenge,a bi-layer perovskite cer...This study focused on meeting the stringent stability requirements of tubular segmented-in-series solid oxide fuel cells(SOFCs) in reducing and oxidizing atmospheres.To address this challenge,a bi-layer perovskite ceramic interconnect was designed by controlling the oxygen partial pressure,because of the strong correlation between the conductivity of strontium-doped lanthanum titanate(LST) and the oxygen partial pressure.The LST powder was prepared using solid-phase and sol-gel methods,and their influence on particle size and sintering behavior was compared.LST/lanthanum strontium manganite(LSM) bi-layer ceramic interconnects with varying thicknesses were fabricated through screen printing and co-sintering.The results demonstrate favorable interfacial bonding and excellent chemical compatibility between the ceramic layers.The conductivity of the bi-layer interconnect exhibits a temperature-dependent behavior,peaking at 550℃.Simulation calculations and research findings validate that the co nductivity of the bi-layer interconnect is determined by the thickness of the LSM layer and the oxygen partial pressure at the interconnect interface.Optimal conductivity is achieved with a bilayer interconnect consisting of approximately 15 μm of LST and 4 μm of LSM.This can be attributed to the efficient regulation of oxygen partial pressure at the interface,effectively mitigating LSM decomposition caused by low oxygen partial pressure and the subsequent reduction in conductivity.These results provide valuable fundamental data and methodology for the development of high-performance interconnects for tubular segmented-in-series SOFCs.展开更多
In this article, we report the preparation of a three-dimensional（3D） interconnected mesoporous anatase TiO2-SiO2 nanocomposite. The nanocomposite was obtained by using an ordered two-dimensional（2D） hexagonal mes...In this article, we report the preparation of a three-dimensional（3D） interconnected mesoporous anatase TiO2-SiO2 nanocomposite. The nanocomposite was obtained by using an ordered two-dimensional（2D） hexagonal mesoporous anatase 70 TiO2-30 SiO2-950 nanocomposite（crystallized at 950 °C for 2 h） as a precursor, NaO H as an etchant of SiO2 via a ＂creating mesopores in the pore walls＂ approach. Our strategy adopts mild conditions of creating pores such as diluted NaO H solution, appropriate temperature and solid/liquid ratio, etc. aiming at ensuring the integrities of mesopores architecture and anatase nanocrystals. XRD, TEM and N2 sorption techniques have been used to systematically investigate the physico-chemical properties of the nanocomposites. The results show that the intrawall mesopores are highly dense and uniform（average pore size 3.6 nm）, and highly link the initial mesochannels in a 3D manner while retaining mesostructural integrity. There is no significant change to either crystallinity or size of the anatase nanocrystals before and after creating the intrawall mesopores. The photocatalytic degradation rates of rhodamine B（RhB, 0.303 min^–1） and methylene blue（MB, 0.757 min^–1） dyes on the resultant nanocomposite are very high, which are 5.1 and 5.3 times that of the precursor; even up to 16.5 and 24.1 times that of Degussa P25 photocatalyst, respectively. These results clearly demonstrate that the 3D interconnected mesopores structure plays an overwhelming role to the increments of activities. The 3D mesoporous anatase TiO2-SiO2 nanocomposite exhibits unexpected-high degradation activities to RhB and MB in the mesoporous metal oxide-based materials reported so far. Additionally, the nanocomposite is considerably stable and reusable. We believe that this method would pave the way for the preparation of other 3D highly interconnected mesoporous metal oxide-based materials with ultra-high performance.展开更多
A new type controller, fuzzy neural networks sliding mode controller (FNNSMC), is developed for a class of large scale systems with unknown bounds of high order interconnections and disturbances. Although sliding mod...A new type controller, fuzzy neural networks sliding mode controller (FNNSMC), is developed for a class of large scale systems with unknown bounds of high order interconnections and disturbances. Although sliding mode control is simple and insensitive to uncertainties and disturbances, there are two main problems in the sliding mode controller (SMC): control input chattering and the assumption of known bounds of uncertainties and disturbances. The FNNSMC, which incorporates the fuzzy neural networks (FNN) and the SMC, can eliminate the chattering by using the continuous output of the FNN to replace the discontinuous sign term in the SMC. The bounds of uncertainties and disturbances are also not required in the FNNSMC design. The simulation results show that the FNNSMC has more robustness than the SMC.展开更多
The current investigations primarily focus on using advanced suspensions to overcome the tradeo design of ride comfort and handling performance for mining vehicles. It is generally realized by adjusting spring sti nes...The current investigations primarily focus on using advanced suspensions to overcome the tradeo design of ride comfort and handling performance for mining vehicles. It is generally realized by adjusting spring sti ness or damping parameters through active control methods. However, some drawbacks regarding control complexity and uncertain reliability are inevitable for these advanced suspensions. Herein, a novel passive hydraulically interconnected suspension(HIS) system is proposed to achieve an improved ride-handling compromise of mining vehicles. A lumped-mass vehicle model involved with a mechanical–hydraulic coupled system is developed by applying the free-body diagram method. The transfer matrix method is used to derive the impedance of the hydraulic system, and the impedance is integrated to form the equation of motions for a mechanical–hydraulic coupled system. The modal analysis method is employed to obtain the free vibration transmissibilities and force vibration responses under di erent road excitations. A series of frequency characteristic analyses are presented to evaluate the isolation vibration performance between the mining vehicles with the proposed HIS and the conventional suspension. The analysis results prove that the proposed HIS system can e ectively suppress the pitch motion of sprung mass to guarantee the handling performance, and favorably provide soft bounce sti ness to improve the ride comfort. The distribution of dynamic forces between the front and rear wheels is more reasonable, and the vibration decay rate of sprung mass is increased e ectively. This research proposes a new suspension design method that can achieve the enhanced cooperative control of bounce and pitch motion modes to improve the ride comfort and handling performance of mining vehicles as an e ective passive suspension system.展开更多
This article considers delay dependent decentralized H∞ filtering for a class of uncertain interconnected systems, where the uncertainties are assumed to be time varying and satisfy the norm-bounded conditions. First...This article considers delay dependent decentralized H∞ filtering for a class of uncertain interconnected systems, where the uncertainties are assumed to be time varying and satisfy the norm-bounded conditions. First, combining the Lyapunov-Krasovskii functional approach and the delay integral inequality of matrices, a sufficient condition of the existence of the robust decentralized H∞ filter is derived, which makes the error systems asymptotically stable and satisfies the H∞ norm of the transfer function from noise input to error output less than the specified up-bound on the basis of the form of uncertainties. Then, the above sufficient condition is transformed to a system of easily solvable LMIs via a series of equivalent transformation. Finally, the numerical simulation shows the efficiency of the main results.展开更多
The paper proposes a novel H∞ load frequency control(LFC) design method for multi-area power systems based on an integral-based non-fragile distributed fixed-order dynamic output feedback(DOF) tracking-regulator cont...The paper proposes a novel H∞ load frequency control(LFC) design method for multi-area power systems based on an integral-based non-fragile distributed fixed-order dynamic output feedback(DOF) tracking-regulator control scheme. To this end, we consider a nonlinear interconnected model for multiarea power systems which also include uncertainties and timevarying communication delays. The design procedure is formulated using semi-definite programming and linear matrix inequality(LMI) method. The solution of the proposed LMIs returns necessary parameters for the tracking controllers such that the impact of model uncertainty and load disturbances are minimized. The proposed controllers are capable of receiving all or part of subsystems information, whereas the outputs of each controller are local. These controllers are designed such that the resilient stability of the overall closed-loop system is guaranteed. Simulation results are provided to verify the effectiveness of the proposed scheme. Simulation results quantify that the distributed(and decentralized) controlled system behaves well in presence of large parameter perturbations and random disturbances on the power system.展开更多
The Interconnected River System Network (IRSN) plays a crucial role in water resource allocation, water ecological restoration and water quality improvement. It has become a key part of the urban lake management. An e...The Interconnected River System Network (IRSN) plays a crucial role in water resource allocation, water ecological restoration and water quality improvement. It has become a key part of the urban lake management. An evaluation methodology system for IRSN project can provide important guidance for the selection of different water diversion schemes. However, few if any comprehensive evaluation systems have been developed to evaluate the hydrodynamics and water quality of connected lakes. This study developed a comprehensive evaluation system based on multi-indexes including aspects of water hydrodynamics, water quality and socioeconomics. A two-dimensional (2-D) mathematical hydrodynamics and water quality model was built, using NH<sub>3</sub>-N, TN and TP as water quality index. The IRSN project in Tangxun Lake group was used as a testbed here, and five water diversion schemes were simulated and evaluated. Results showed that the IRSN project can improve the water fluidity and the water quality obviously after a short time of water diversion, while the improvement rates decreased gradually as the water diversion went on. Among these five schemes, Scheme V showed the most noticeable improvement in hydrodynamics and water quality, and brought the most economic benefits. This comprehensive evaluation method can provide useful reference for the implementation of other similar IRSN projects.展开更多
This paper deals with analysis and synthesis problems of spatially interconnected systems where communicated information may get lost between subsystems. Spatial shift operator and temporal forward shift operator are ...This paper deals with analysis and synthesis problems of spatially interconnected systems where communicated information may get lost between subsystems. Spatial shift operator and temporal forward shift operator are introduced to model the interconnected systems as discrete time-space multidimensional linear systems with Markovian jumping parameters which reflect the state of communication channels. To ensure the whole system＇s well-posedness and mean square stability for a given packet loss rate, a condition is derived through analysis. Then a procedure of designing distributed dynamic output feedback controllers is proposed. The controllers have the same structure as the plants and are solved within the linear matrix inequality （LMI） framework. Finally, we apply these results to study the effect of communication losses on the multiple vehicle platoon control system, which further illustrates the effectiveness of the proposed model and method.展开更多
Hierarchically interconnected porous activated carbon have high specific surface areas, large numbers of dye adsorption sites, and interconnected pores for dye molecule diffusion and transportation. We prepared hierar...Hierarchically interconnected porous activated carbon have high specific surface areas, large numbers of dye adsorption sites, and interconnected pores for dye molecule diffusion and transportation. We prepared hierarchically interconnected porous banana peel activated carbons(BPACs) via a green method involving hydrothermal pretreatment and KOH activation, and systematically tested its methylene blue(MB) adsorption capacity. SEM showed that the BPACs had an interconnected porous structure and high-porosity surface. The Brunauer-Emmett-Teller surface area was 601.21 m^2/g, the adsorption average pore diameter was 2.11 nm, and the total pore volume was 0.32 cm^3/g. The MB adsorption capacity increased with increasing temperature, initial MB concentration, and pH value; it decreased with increasing adsorbent dosage. The adsorption isotherms and kinetic results for MB adsorption on BPACs were best described by the Langmuir adsorption and pseudo-second-order kinetic models, respectively. BPACs have a well-developed hierarchically interconnected porous structure, which increase the MB adsorption capacity and removal efficiency. Systematic MB adsorption tests show that BPAC is a highly efficient and easily available adsorbent.展开更多
This paper is concerned with the decentralized stabilization of continuous and discrete linear interconnected systems with the structural constraints about the interconnection matrices. For the continuous case,the mai...This paper is concerned with the decentralized stabilization of continuous and discrete linear interconnected systems with the structural constraints about the interconnection matrices. For the continuous case,the main improvement in the paper as compared with the corresponding results in the literature is to extend the considered class of systems from S to S (both will be defined in the paper) without resulting in high decentralized gain and difficult numerical computation. The algorithm for obtaining decentralized state feedback control to stable the overall system is presented. The discrete case and some very useful results are discussed as well.展开更多
Three-dimensional （3D） interconnected porous architectures are expected to perform well in photoelectrochemical （PEC） water splitting due to their high specific surface area as well as favourable porous properties...Three-dimensional （3D） interconnected porous architectures are expected to perform well in photoelectrochemical （PEC） water splitting due to their high specific surface area as well as favourable porous properties and interconnections. In this work, we demonstrated the facile fabrication of 3D interconnected nanoporous N-doped TiO2 （N-TiO2 network） by annealing the anodized 3D interconnected nanoporous TiO2 （TiO2 network） in ammonia atmosphere. The obtained N-TiO2 network exhibited broadened light absorption, and abundant, interconnected pores for improving charge separation, which was supported by the reduced charge transfer resistance. With these merits, a remarkably high photocurrent density at 1.23 V vs. reversible hydrogen electrode （RHE） was realized for the N-TiO2 network without any co-catalysts or sacrificial reagents, and the photostability can be assured after long term illumination. In view of its simplicity and efficiency, this structure promises for perspective PEC applications.展开更多
基金supported by the National Natural Science Foundation of China(62273213,62073199,62103241)Natural Science Foundation of Shandong Province for Innovation and Development Joint Funds(ZR2022LZH001)+4 种基金Natural Science Foundation of Shandong Province(ZR2020MF095,ZR2021QF107)Taishan Scholarship Construction Engineeringthe Original Exploratory Program Project of National Natural Science Foundation of China(62250056)Major Basic Research of Natural Science Foundation of Shandong Province(ZR2021ZD14)High-level Talent Team Project of Qingdao West Coast New Area(RCTD-JC-2019-05)。
文摘The paper addresses the decentralized optimal control and stabilization problems for interconnected systems subject to asymmetric information.Compared with previous work,a closed-loop optimal solution to the control problem and sufficient and necessary conditions for the stabilization problem of the interconnected systems are given for the first time.The main challenge lies in three aspects:Firstly,the asymmetric information results in coupling between control and estimation and failure of the separation principle.Secondly,two extra unknown variables are generated by asymmetric information(different information filtration)when solving forward-backward stochastic difference equations.Thirdly,the existence of additive noise makes the study of mean-square boundedness an obstacle.The adopted technique is proving and assuming the linear form of controllers and establishing the equivalence between the two systems with and without additive noise.A dual-motor parallel drive system is presented to demonstrate the validity of the proposed algorithm.
文摘The primary factor contributing to frequency instability in microgrids is the inherent intermittency of renewable energy sources.This paper introduces novel dual-backup controllers utilizing advanced fractional order proportional integral derivative(FOPID)controllers to enhance frequency and tie-line power stability in microgrids amid increasing renewable energy integration.To improve load frequency control,the proposed controllers are applied to a two-area interconnectedmicrogrid system incorporating diverse energy sources,such as wind turbines,photovoltaic cells,diesel generators,and various storage technologies.A novelmeta-heuristic algorithm is adopted to select the optimal parameters of the proposed controllers.The efficacy of the advanced FOPID controllers is demonstrated through comparative analyses against traditional proportional integral derivative(PID)and FOPID controllers,showcasing superior performance inmanaging systemfluctuations.The optimization algorithm is also evaluated against other artificial intelligent methods for parameter optimization,affirming the proposed solution’s efficiency.The robustness of the intelligent controllers against system uncertainties is further validated under extensive power disturbances,proving their capability to maintain grid stability.The dual-controller configuration ensures redundancy,allowing them to operate as mutual backups,enhancing system reliability.This research underlines the importance of sophisticated control strategies for future-proofing microgrid operations against the backdrop of evolving energy landscapes.
文摘This paper presents an analysis of the power flow within the Northern Interconnected Grid of Cameroon. The Newton-Raphson method has been performed, known for its accuracy, under MATLAB software, to model and solve complex power flow equations. This study simulates a series of outage scenarios to evaluate the responsiveness of the grid. The results obtained underline the crucial importance of reactive power management and highlight the urgent need to consolidate the grid infrastructure of North Cameroon. To increase grid resilience and stability, the paper recommends the strategic integration of renewables and the development of interconnections with other power grids. These measures are presented as viable solutions to meet current and future energy distribution challenges, ensuring a reliable and sustainable power supply for Cameroon.
基金supported by National Key Research and Development Program of China(No.2023YFB2704200)Beijing Natural Science Foundation(No.4254064).
文摘With the rapid development of network technologies,a large number of deployed edge devices and information systems generate massive amounts of data which provide good support for the advancement of data-driven intelligent models.However,these data often contain sensitive information of users.Federated learning(FL),as a privacy preservation machine learning setting,allows users to obtain a well-trained model without sending the privacy-sensitive local data to the central server.Despite the promising prospect of FL,several significant research challenges need to be addressed before widespread deployment,including network resource allocation,model security,model convergence,etc.In this paper,we first provide a brief survey on some of these works that have been done on FL and discuss the motivations of the Communication Networks(CNs)and FL to mutually enable each other.We analyze the support of network technologies for FL,which requires frequent communication and emphasizes security,as well as the studies on the intelligence of many network scenarios and the improvement of network performance and security by the methods based on FL.At last,some challenges and broader perspectives are explored.
基金supported by the National Science Foundation of China under the Grant Nos.12127806 and 62175195the International Joint Research Laboratory for Micro/Nano Manufacturing and Measurement Technologies。
文摘High-density interconnect(HDI)soft electronics that can integrate multiple individual functions into one miniaturized monolithic system is promising for applications related to smart healthcare,soft robotics,and human-machine interactions.However,despite the recent advances,the development of three-dimensional(3D)soft electronics with both high resolution and high integration is still challenging because of the lack of efficient manufacturing methods to guarantee interlayer alignment of the high-density vias and reliable interlayer electrical conductivity.Here,an advanced 3D laser printing pathway,based on femtosecond laser direct writing(FLDW),is demonstrated for preparing liquid metal(LM)-based any layer HDI soft electronics.FLDW technology,with the characteristics of high spatial resolution and high precision,allows the maskless fabrication of high-resolution embedded LM microchannels and high-density vertical interconnect accesses for 3D integrated circuits.High-aspect-ratio blind/through LM microstructures are formed inside the elastomer due to the supermetalphobicity induced during laser ablation.The LM-based HDI circuit featuring high resolution(~1.5μm)and high integration(10-layer electrical interconnection)is achieved for customized soft electronics,including various customized multilayer passive electric components,soft multilayer circuit,and cross-scale multimode sensors.The 3D laser printing method provides a versatile approach for developing chip-level soft electronics.
基金supported by the National Natural Science Foundation of China(Grant Nos.62405250 and 62471404)the China Postdoctoral Science Foundation(Grant No.2024M762955)+1 种基金the Key Project of Westlake Institute for Optoelectronics(Grant No.2023GD003)the Optical Com-munication and Sensing Laboratory,School of Engineering,Westlake University.
文摘Propelled by the rise of artificial intelligence,cloud services,and data center applications,next-generation,low-power,local-oscillator-less,digital signal processing(DSP)-free,and short-reach coherent optical communication has evolved into an increasingly prominent area of research in recent years.Here,we demonstrate DSP-free coherent optical transmission by analog signal processing in frequency synchronous optical network(FSON)architecture,which supports polarization multiplexing and higher-order modulation formats.The FSON architecture that allows the numerous laser sources of optical transceivers within a data center can be quasi-synchronized by means of a tree-distributed homology architecture.In conjunction with our proposed pilot-tone assisted Costas loop for an analog coherent receiver,we achieve a record dual-polarization 224-Gb/s 16-QAM 5-km mismatch transmission with reset-free carrier phase recovery in the optical domain.Our proposed DSP-free analog coherent detection system based on the FSON makes it a promising solution for next-generation,low-power,and high-capacity coherent data center interconnects.
基金support of the National Key Research and Development Program of China(Grant No.2023YFB4202503)Tianjin Science and Technology Project(Grant No.24ZXZSSS00120)+4 种基金the Joint Funds of the National Natural Science Foundation of China(Grant No.U21A2072)Yunnan Provincial Science and Technology Project at Southwest United Graduate School(Grant No.202302A0370009)the Overseas Expertise Introduction Project for Discipline Innovation of Higher Education of China(Grant No.B16027)the project of high-efficiency heterojunction solar cell technology and equipment industrialization(Grant No.TC220A04A-159)TCL science and technology innovation fund.Financial support was provided by the Haihe Laboratory of Sustainable Chemical Transformations,and the Fundamental Research Funds for the Central Universities,Nankai University.
文摘As the development of single-junction solar cells reaches a bottleneck,tandem solar cells have emerged as a critical pathway to further enhance power conversion efficiency.Among them,monolithic perovskite/silicon heterojunction tandem solar cells are currently the fastest-growing technology,achieving the highest efficiencies at relatively low costs.The intercon-necting layer,which connects the two sub-cells,plays a crucial role in tandem cell performance.It collects electrons and holes from the respective sub-cells and facilitates recombination and tunneling at the interface.Therefore,the properties of the inter-connecting layer are pivotal to the overall device performance.In this work,we applied statistical analysis and machine learn-ing algorithms to systematically analyze the interconnecting layer.A comprehensive dataset on interconnecting layer parame-ters was established,and predictive modeling was performed using Lasso linear regression,random forest,and multilayer per-ceptron(a type of neural network).The analysis revealed key feature importance for experimental parameters,providing valu-able insights into the application of interconnecting layers in perovskite/silicon heterojunction tandem solar cells.The final opti-mized interconnecting layer can achieve a proof-of-concept efficiency of 38.17%,providing guidance and direction for the devel-opment of monolithic perovskite/silicon tandem solar cells.
基金supported in part by an International Research Partnership“Electrical Engineering-Thai French Research Center(EE-TFRC)”under the project framework of the Lorraine Universite´d’Excellence(LUE)in cooperation between Universite´de Lorraine(France)and King Mongkut’s University of Technology North Bangkok(year 2021-2024/2025-28)by the National Research Council of Thailand(NRCT)under Research Team Promotion Grant(Senior Research Scholar Program)under Grant No.N42A 680561by the NSRF via the Program Management Unit for Human Resources&Institutional Development,Research and Innovation under Research project Grant No.B41G680025.
文摘Permanent Magnet Synchronous Motors(PMSMs)are widely employed in high-performance drive applications due to their superior efficiency and dynamic capabilities.However,their control remains challenging owing to nonlinear dynamics,parameter variations,and unmeasurable external disturbances,particularly load torquefluctuations.This study proposes an enhanced Interconnection and Damp-ing Assignment Passivity-Based Control(IDA-PBC)scheme,formulated within the port-controlled Hamiltonian(PCH)framework,to address these limitations.A nonlinear disturbance observer is embedded to estimate and compensate,in real time,for lumped mis-matched disturbances arising from parameter uncertainties and external loads.Additionally,aflatness-based control strategy is employed to generate the desired current references within the nonlinear drive system,ensuring accurate tracking of time-varying speed commands.This integrated approach preserves the system’s energy-based structure,enabling systematic stability analysis while enhancing robustness.The proposed control architecture also maintains low complexity with a limited number of tunable parameters,facilitating practical implementation.Simulation and experimental results under various operating conditions demonstrate the effectiveness and robustness of the proposed method.Comparative analysis with conventional proportional-integral(PI)control and standard IDA-PBC strategies confirms its capability to handle disturbances and maintain dynamic performance.
基金Project supported by the National Key Research and Development Program of China (2021YFB4001400)。
文摘This study focused on meeting the stringent stability requirements of tubular segmented-in-series solid oxide fuel cells(SOFCs) in reducing and oxidizing atmospheres.To address this challenge,a bi-layer perovskite ceramic interconnect was designed by controlling the oxygen partial pressure,because of the strong correlation between the conductivity of strontium-doped lanthanum titanate(LST) and the oxygen partial pressure.The LST powder was prepared using solid-phase and sol-gel methods,and their influence on particle size and sintering behavior was compared.LST/lanthanum strontium manganite(LSM) bi-layer ceramic interconnects with varying thicknesses were fabricated through screen printing and co-sintering.The results demonstrate favorable interfacial bonding and excellent chemical compatibility between the ceramic layers.The conductivity of the bi-layer interconnect exhibits a temperature-dependent behavior,peaking at 550℃.Simulation calculations and research findings validate that the co nductivity of the bi-layer interconnect is determined by the thickness of the LSM layer and the oxygen partial pressure at the interconnect interface.Optimal conductivity is achieved with a bilayer interconnect consisting of approximately 15 μm of LST and 4 μm of LSM.This can be attributed to the efficient regulation of oxygen partial pressure at the interface,effectively mitigating LSM decomposition caused by low oxygen partial pressure and the subsequent reduction in conductivity.These results provide valuable fundamental data and methodology for the development of high-performance interconnects for tubular segmented-in-series SOFCs.
基金supported by the National Natural Science Foundation of China(21373056)the Science and Technology Commission of Shanghai Municipality(13DZ2275200)~~
文摘In this article, we report the preparation of a three-dimensional（3D） interconnected mesoporous anatase TiO2-SiO2 nanocomposite. The nanocomposite was obtained by using an ordered two-dimensional（2D） hexagonal mesoporous anatase 70 TiO2-30 SiO2-950 nanocomposite（crystallized at 950 °C for 2 h） as a precursor, NaO H as an etchant of SiO2 via a ＂creating mesopores in the pore walls＂ approach. Our strategy adopts mild conditions of creating pores such as diluted NaO H solution, appropriate temperature and solid/liquid ratio, etc. aiming at ensuring the integrities of mesopores architecture and anatase nanocrystals. XRD, TEM and N2 sorption techniques have been used to systematically investigate the physico-chemical properties of the nanocomposites. The results show that the intrawall mesopores are highly dense and uniform（average pore size 3.6 nm）, and highly link the initial mesochannels in a 3D manner while retaining mesostructural integrity. There is no significant change to either crystallinity or size of the anatase nanocrystals before and after creating the intrawall mesopores. The photocatalytic degradation rates of rhodamine B（RhB, 0.303 min^–1） and methylene blue（MB, 0.757 min^–1） dyes on the resultant nanocomposite are very high, which are 5.1 and 5.3 times that of the precursor; even up to 16.5 and 24.1 times that of Degussa P25 photocatalyst, respectively. These results clearly demonstrate that the 3D interconnected mesopores structure plays an overwhelming role to the increments of activities. The 3D mesoporous anatase TiO2-SiO2 nanocomposite exhibits unexpected-high degradation activities to RhB and MB in the mesoporous metal oxide-based materials reported so far. Additionally, the nanocomposite is considerably stable and reusable. We believe that this method would pave the way for the preparation of other 3D highly interconnected mesoporous metal oxide-based materials with ultra-high performance.
文摘A new type controller, fuzzy neural networks sliding mode controller (FNNSMC), is developed for a class of large scale systems with unknown bounds of high order interconnections and disturbances. Although sliding mode control is simple and insensitive to uncertainties and disturbances, there are two main problems in the sliding mode controller (SMC): control input chattering and the assumption of known bounds of uncertainties and disturbances. The FNNSMC, which incorporates the fuzzy neural networks (FNN) and the SMC, can eliminate the chattering by using the continuous output of the FNN to replace the discontinuous sign term in the SMC. The bounds of uncertainties and disturbances are also not required in the FNNSMC design. The simulation results show that the FNNSMC has more robustness than the SMC.
基金Supported by National Natural Science Foundation of China(Grant Nos.51805155,51675152)Foundation for Innovative Research Groups of National Natural Science Foundation of China(Grant No.51621004)Open Fund in the State Key Laboratory of Advanced Design and Manufacture for Vehicle Body(Grant No.71575005)
文摘The current investigations primarily focus on using advanced suspensions to overcome the tradeo design of ride comfort and handling performance for mining vehicles. It is generally realized by adjusting spring sti ness or damping parameters through active control methods. However, some drawbacks regarding control complexity and uncertain reliability are inevitable for these advanced suspensions. Herein, a novel passive hydraulically interconnected suspension(HIS) system is proposed to achieve an improved ride-handling compromise of mining vehicles. A lumped-mass vehicle model involved with a mechanical–hydraulic coupled system is developed by applying the free-body diagram method. The transfer matrix method is used to derive the impedance of the hydraulic system, and the impedance is integrated to form the equation of motions for a mechanical–hydraulic coupled system. The modal analysis method is employed to obtain the free vibration transmissibilities and force vibration responses under di erent road excitations. A series of frequency characteristic analyses are presented to evaluate the isolation vibration performance between the mining vehicles with the proposed HIS and the conventional suspension. The analysis results prove that the proposed HIS system can e ectively suppress the pitch motion of sprung mass to guarantee the handling performance, and favorably provide soft bounce sti ness to improve the ride comfort. The distribution of dynamic forces between the front and rear wheels is more reasonable, and the vibration decay rate of sprung mass is increased e ectively. This research proposes a new suspension design method that can achieve the enhanced cooperative control of bounce and pitch motion modes to improve the ride comfort and handling performance of mining vehicles as an e ective passive suspension system.
基金the National Natural Science Foundation of China (60634020)the Hunan Provincial Natural Science Foundation of China (07JJ6138)+1 种基金the Postdoctoral Science Foundation of China (20060390883)the China Ph.D. Discipline Special Foundation (20050533028).
文摘This article considers delay dependent decentralized H∞ filtering for a class of uncertain interconnected systems, where the uncertainties are assumed to be time varying and satisfy the norm-bounded conditions. First, combining the Lyapunov-Krasovskii functional approach and the delay integral inequality of matrices, a sufficient condition of the existence of the robust decentralized H∞ filter is derived, which makes the error systems asymptotically stable and satisfies the H∞ norm of the transfer function from noise input to error output less than the specified up-bound on the basis of the form of uncertainties. Then, the above sufficient condition is transformed to a system of easily solvable LMIs via a series of equivalent transformation. Finally, the numerical simulation shows the efficiency of the main results.
文摘The paper proposes a novel H∞ load frequency control(LFC) design method for multi-area power systems based on an integral-based non-fragile distributed fixed-order dynamic output feedback(DOF) tracking-regulator control scheme. To this end, we consider a nonlinear interconnected model for multiarea power systems which also include uncertainties and timevarying communication delays. The design procedure is formulated using semi-definite programming and linear matrix inequality(LMI) method. The solution of the proposed LMIs returns necessary parameters for the tracking controllers such that the impact of model uncertainty and load disturbances are minimized. The proposed controllers are capable of receiving all or part of subsystems information, whereas the outputs of each controller are local. These controllers are designed such that the resilient stability of the overall closed-loop system is guaranteed. Simulation results are provided to verify the effectiveness of the proposed scheme. Simulation results quantify that the distributed(and decentralized) controlled system behaves well in presence of large parameter perturbations and random disturbances on the power system.
基金National Key Research and Development Program,No.2017YFA0603704,No.2017YFC1502500
文摘The Interconnected River System Network (IRSN) plays a crucial role in water resource allocation, water ecological restoration and water quality improvement. It has become a key part of the urban lake management. An evaluation methodology system for IRSN project can provide important guidance for the selection of different water diversion schemes. However, few if any comprehensive evaluation systems have been developed to evaluate the hydrodynamics and water quality of connected lakes. This study developed a comprehensive evaluation system based on multi-indexes including aspects of water hydrodynamics, water quality and socioeconomics. A two-dimensional (2-D) mathematical hydrodynamics and water quality model was built, using NH<sub>3</sub>-N, TN and TP as water quality index. The IRSN project in Tangxun Lake group was used as a testbed here, and five water diversion schemes were simulated and evaluated. Results showed that the IRSN project can improve the water fluidity and the water quality obviously after a short time of water diversion, while the improvement rates decreased gradually as the water diversion went on. Among these five schemes, Scheme V showed the most noticeable improvement in hydrodynamics and water quality, and brought the most economic benefits. This comprehensive evaluation method can provide useful reference for the implementation of other similar IRSN projects.
文摘This paper deals with analysis and synthesis problems of spatially interconnected systems where communicated information may get lost between subsystems. Spatial shift operator and temporal forward shift operator are introduced to model the interconnected systems as discrete time-space multidimensional linear systems with Markovian jumping parameters which reflect the state of communication channels. To ensure the whole system＇s well-posedness and mean square stability for a given packet loss rate, a condition is derived through analysis. Then a procedure of designing distributed dynamic output feedback controllers is proposed. The controllers have the same structure as the plants and are solved within the linear matrix inequality （LMI） framework. Finally, we apply these results to study the effect of communication losses on the multiple vehicle platoon control system, which further illustrates the effectiveness of the proposed model and method.
基金Funded by the Project of Scientific Research Staring Foundation of Huaqiao University(11BS214)the Cultivate Project of National Natural Science Foundation of Huaqiao University(JBZR1214)the Educational research project for Young and middle-aged Teachers of Fujian Province(JAT160031)
文摘Hierarchically interconnected porous activated carbon have high specific surface areas, large numbers of dye adsorption sites, and interconnected pores for dye molecule diffusion and transportation. We prepared hierarchically interconnected porous banana peel activated carbons(BPACs) via a green method involving hydrothermal pretreatment and KOH activation, and systematically tested its methylene blue(MB) adsorption capacity. SEM showed that the BPACs had an interconnected porous structure and high-porosity surface. The Brunauer-Emmett-Teller surface area was 601.21 m^2/g, the adsorption average pore diameter was 2.11 nm, and the total pore volume was 0.32 cm^3/g. The MB adsorption capacity increased with increasing temperature, initial MB concentration, and pH value; it decreased with increasing adsorbent dosage. The adsorption isotherms and kinetic results for MB adsorption on BPACs were best described by the Langmuir adsorption and pseudo-second-order kinetic models, respectively. BPACs have a well-developed hierarchically interconnected porous structure, which increase the MB adsorption capacity and removal efficiency. Systematic MB adsorption tests show that BPAC is a highly efficient and easily available adsorbent.
基金National Natural Science Foundation of China(1 970 1 0 2 2 )
文摘This paper is concerned with the decentralized stabilization of continuous and discrete linear interconnected systems with the structural constraints about the interconnection matrices. For the continuous case,the main improvement in the paper as compared with the corresponding results in the literature is to extend the considered class of systems from S to S (both will be defined in the paper) without resulting in high decentralized gain and difficult numerical computation. The algorithm for obtaining decentralized state feedback control to stable the overall system is presented. The discrete case and some very useful results are discussed as well.
基金financially supported by the National Natural Science Foundation of China(Grant Nos.51503014 and 51501008)the State Key Laboratory for Advanced Metals and Materials(No.2016Z-03)
文摘Three-dimensional （3D） interconnected porous architectures are expected to perform well in photoelectrochemical （PEC） water splitting due to their high specific surface area as well as favourable porous properties and interconnections. In this work, we demonstrated the facile fabrication of 3D interconnected nanoporous N-doped TiO2 （N-TiO2 network） by annealing the anodized 3D interconnected nanoporous TiO2 （TiO2 network） in ammonia atmosphere. The obtained N-TiO2 network exhibited broadened light absorption, and abundant, interconnected pores for improving charge separation, which was supported by the reduced charge transfer resistance. With these merits, a remarkably high photocurrent density at 1.23 V vs. reversible hydrogen electrode （RHE） was realized for the N-TiO2 network without any co-catalysts or sacrificial reagents, and the photostability can be assured after long term illumination. In view of its simplicity and efficiency, this structure promises for perspective PEC applications.
