This article deals with the consensus problem of multi-agent systems by developing a fixed-time consensus control approach with a dynamic event-triggered rule. First, a new fixedtime stability condition is obtained wh...This article deals with the consensus problem of multi-agent systems by developing a fixed-time consensus control approach with a dynamic event-triggered rule. First, a new fixedtime stability condition is obtained where the less conservative settling time is given such that the theoretical settling time can well reflect the real consensus time. Second, a dynamic event-triggered rule is designed to decrease the use of chip and network resources where Zeno behaviors can be avoided after consensus is achieved, especially for finite/fixed-time consensus control approaches. Third, in terms of the developed dynamic event-triggered rule, a fixed-time consensus control approach by introducing a new item is proposed to coordinate the multi-agent system to reach consensus. The corresponding stability of the multi-agent system with the proposed control approach and dynamic eventtriggered rule is analyzed based on Lyapunov theory and the fixed-time stability theorem. At last, the effectiveness of the dynamic event-triggered fixed-time consensus control approach is verified by simulations and experiments for the problem of magnetic map construction based on multiple mobile robots.展开更多
To address fixed-time consensus problems of a class of leader-follower second-order nonlinear multi-agent systems with uncertain external disturbances,the event-triggered fixed-time consensus protocol is proposed.Firs...To address fixed-time consensus problems of a class of leader-follower second-order nonlinear multi-agent systems with uncertain external disturbances,the event-triggered fixed-time consensus protocol is proposed.First,the virtual velocity is designed based on the backstepping control method to achieve the system consensus and the bound on convergence time only depending on the system parameters.Second,an event-triggered mechanism is presented to solve the problem of frequent communication between agents,and triggered condition based on state information is given for each follower.It is available to save communication resources,and the Zeno behaviors are excluded.Then,the delay and switching topologies of the system are also discussed.Next,the system stabilization is analyzed by Lyapunov stability theory.Finally,simulation results demonstrate the validity of the presented method.展开更多
We analyse the fixed-time consensus problem for multi-agent systems with leaderfollower mode. Based on a follower’s observation structure for the leader’s information, it is proved that the estimation errors can be ...We analyse the fixed-time consensus problem for multi-agent systems with leaderfollower mode. Based on a follower’s observation structure for the leader’s information, it is proved that the estimation errors can be converged to zero at a fixed time. From this stability and a sliding mode structure, we derive a control input of followers, which provides a critical support for fixed-time consensus. The simulation results demonstrate that this control approach does conduce to the implementation of the fixed-time synchronization.展开更多
In this paper,the problem of non-singular fixed-time control with prescribed performance is studied for multi-agent systems characterized by uncertain states,nonlinearities,and nonstrict feedback.To mitigate the nonli...In this paper,the problem of non-singular fixed-time control with prescribed performance is studied for multi-agent systems characterized by uncertain states,nonlinearities,and nonstrict feedback.To mitigate the nonlinearity,a fuzzy logic algorithm is applied to approximate the intrinsic dynamics of the system.Furthermore,a fuzzy logic system state observer based on leader state information is designed to address the partial unob-servability of followers.Subsequently,the power integral method is incorporated into the backstepping approach to avoid singularities in the fixed-time controller.A command filter method is introduced into the standard backstepping approach to reduce the computational complexity of controller design.Then,a non-singular fixed-time adaptive control strategy with prescribed performance is proposed by constraining the tracking error within a prescribed range.Rigorous theoretical analysis ensures the convergence of consensus error in the multi-agent system to the prescribed performance region within a fixed time.Finally,the practicality of the algorithm is validated through numerical simulations.展开更多
This paper investigates the sliding-mode-based fixed-time distributed average tracking (DAT) problem for multiple Euler-Lagrange systems in the presence of external distur-bances. The primary objective is to devise co...This paper investigates the sliding-mode-based fixed-time distributed average tracking (DAT) problem for multiple Euler-Lagrange systems in the presence of external distur-bances. The primary objective is to devise controllers for each agent, enabling them to precisely track the average of multiple time-varying reference signals. By averaging these signals, we can mitigate the influence of errors and uncertainties arising dur-ing measurements, thereby enhancing the robustness and stabi-lity of the system. A distributed fixed-time average estimator is proposed to estimate the average value of global reference sig-nals utilizing local information and communication with neigh-bors. Subsequently, a fixed-time sliding mode controller is intro-duced incorporating a state-dependent sliding mode function coupled with a variable exponent coefficient to achieve dis-tributed average tracking of reference signals, and rigorous ana-lytical methods are employed to substantiate the fixed-time sta-bility. Finally, numerical simulation results are provided to vali-date the effectiveness of the proposed methodology, offering insights into its practical application and robust performance.展开更多
Background:Insufficient physical activity and prolonged sedentary behavior have emerged as major global public health challenges.Short bouts(≤10 min)of accumulated exercise(SBAE)throughout the day may be a promising ...Background:Insufficient physical activity and prolonged sedentary behavior have emerged as major global public health challenges.Short bouts(≤10 min)of accumulated exercise(SBAE)throughout the day may be a promising strategy to mitigate the adverse effects of prolonged sitting and promote physical activity,ultimately promoting overall health.However,previous ambiguity in defining this concept has resulted in a fragmented and inconsistent evidence base,impeding practical applications,the development of guidelines,and policymaking.The purpose of this study is to establish an operational definition of SBAE by synthesizing systematic reviews and research trials alongside an expert consensus.Additionally,it seeks to evaluate acute and long-term efficacy and feasibility,providing evidence-based recommendations for practice and future research directions.Methods:A literature search was performed across PubMed and Web of Science,followed by systematic screening and summarization of eligible studies based on predefined inclusion criteria.Inclusion criteria encompassed various modes/types of SBAE(bouts lasting≤10 min,performed multiple times daily with≥30 min intervals);both aerobic and resistance exercise were considered.Relevant systematic reviews and research trials were included.Methodological quality,risk of bias,and evidence certainty were assessed.Expert consensus was obtained through a survey to evaluate recommendations and agreement levels on findings.Results:After analyzing 27 systematic reviews,135 research studies,and an expert consensus involving 48 researchers from 11 countries,SBAE is defined as any exercise mode of activity,regardless of intensity,that is accumulated in either continuous or intermittent bouts lasting≤10 min per session(including multiple intermittent sets)that are performed multiple times(≥2 sessions/day)per day,with intervals of≥30 min between bouts or otherwise sufficient time for recovery.When used to interrupt prolonged periods of sedentary time,SBAE mitigates the acute adverse effects of sedentary behavior on more than 10 clinical biomarkers of endocrine,cardiovascular,and brain health/function among adults of diverse ages and conditions.Moreover,SBAE was superior for improving acute glycemic control compared to a single continuous exercise session.As a long-term intervention(average of 11 weeks),SBAE can improve over 20 health outcomes,including peak oxygen uptake,resting blood pressure,and metabolic health.Additionally,SBAE might be more effective than continuous exercise for improving longer-term glycemic control and body composition.Long-term completion rates for SBAE interventions are generally high(95%),with low dropout rates(12%)and high adherence rates even without supervision(85%),and its safety has been preliminarily validated.Conclusion:An operational definition of SBAE is provided along with its classification and acute and long-term efficacy.Practical exercise prescription recommendations and evidence-based strategies for various populations and contexts are provided.Future research should focus on generating high-quality evidence for SBAE in 5 key areas:quantification and monitoring,population-specific responses,optimization of exercise prescriptions,intervention efficacy,and practical implementation.Additionally,addressing policy,environmental,and promotional barriers is crucial for transitioning from expert consensus to public consensus,and for facilitating the application of this strategy in real-world environments.展开更多
This paper is dedicated to fixed-time passivity and synchronization for multi-weighted spatiotemporal directed networks.First,to achieve fixed-time passivity,a type of decentralized power-law controller is developed,i...This paper is dedicated to fixed-time passivity and synchronization for multi-weighted spatiotemporal directed networks.First,to achieve fixed-time passivity,a type of decentralized power-law controller is developed,in which only one parameter needs to be adjusted in the power-law terms;this greatly decreases the inconvenience of parameter adjustment.Second,several fixed-time passivity criteria with LMI forms are derived by using a Gauss divergence theorem to deal with the spatial diffusion of nodes and by applying the Hölder’s inequality to dispose rigorously the power-law term greater than one in the designed control scheme;this improves the previous theoretical analysis.Additionally,the fixed-time synchronization of spatiotemporal directed networks with multi-weights is addressed as a direct result of fixed-time strict passivity.Finally,a numerical example is presented in order to show the validity of the theoretical analysis.展开更多
Practical byzantine fault tolerance(PBFT)can reduce energy consumption and achieve high throughput compared with the traditional PoW algorithm,which is more suitable for a strongly consistent consortium blockchain.How...Practical byzantine fault tolerance(PBFT)can reduce energy consumption and achieve high throughput compared with the traditional PoW algorithm,which is more suitable for a strongly consistent consortium blockchain.However,due to the frequent communication among nodes,PBFT cannot realize scalability in large-scale networks.Existing PBFTbased algorithms still ignore performance and security.Therefore,we propose a secure and efficient practical byzantine fault tolerance based on double layers and multi copies(DM-PBFT).We design a reputation evaluation and node scheduling method for DMPBFT.And then we propose an adaptive node scheduling strategy based on the derived threshold values after analyzing the system communication complexity and security.Combining the above research,a node dynamic adjustment mechanism is proposed to freeze or adjust the node operation status according to the system environment.Simulation experiments show that the proposed mechanism can improve efficiency and increase the system’s throughput.展开更多
The Internet of Vehicles(IoV)operates in highly dynamic and open network environments and faces serious challenges in secure and real-time authentication and consensus mechanisms.Existing methods often suffer from com...The Internet of Vehicles(IoV)operates in highly dynamic and open network environments and faces serious challenges in secure and real-time authentication and consensus mechanisms.Existing methods often suffer from complex certificate management,inefficient consensus protocols,and poor resilience in high-frequency communication,resulting in high latency,poor scalability,and unstable network performance.To address these issues,this paper proposes a secure and efficient distributed authentication scheme for IoV with reputation-driven consensus and SM9.First,this paper proposes a decentralized authentication architecture that utilizes the certificate-free feature of SM9,enabling lightweight authentication and key negotiation,thereby reducing the complexity of key management.To ensure the traceability and global consistency of authentication data,this scheme also integrates blockchain technology,applying its inherent invariance.Then,this paper introduces a reputation-driven dynamic node grouping mechanism that transparently evaluates and groups’node behavior using smart contracts to enhance network stability.Furthermore,a new RBSFT(Reputation-Based SM9 Friendly-Tolerant)consensus mechanism is proposed for the first time to enhance consensus efficiency by optimizing the PBFT algorithm.RBSFT aims to write authentication information into the blockchain ledger to achieve multi-level optimization of trust management and decision-making efficiency,thereby significantly improving the responsiveness and robustness in high-frequency IoV scenarios.Experimental results show that it excels in authentication,communication efficiency,and computational cost control,making it a feasible solution for achieving IoV security and real-time performance.展开更多
This paper focuses on the leader-following positive consensus problems of heterogeneous switched multi-agent systems.First,a state-feedback controller with dynamic compensation is introduced to achieve positive consen...This paper focuses on the leader-following positive consensus problems of heterogeneous switched multi-agent systems.First,a state-feedback controller with dynamic compensation is introduced to achieve positive consensus under average dwell time switching.Then sufficient conditions are derived to guarantee the positive consensus.The gain matrices of the control protocol are described using a matrix decomposition approach and the corresponding computational complexity is reduced by resorting to linear programming and co-positive Lyapunov functions.Finally,two numerical examples are provided to illustrate the results obtained.展开更多
Introduction,Breast cancer is the most common cancer type in adolescents and young adults<40 years of age,accounting for 30%of cancers in this age group1.Breast cancer in the young presents significant challenges f...Introduction,Breast cancer is the most common cancer type in adolescents and young adults<40 years of age,accounting for 30%of cancers in this age group1.Breast cancer in the young presents significant challenges for patients and society,including more aggressive tumor biology,poor prognosis,genetic susceptibility,fertility preservation,and complex psychosocial issues.Moreover,because of the markedly younger median age of breast cancer,the proportion of young breast cancer patients in China is significantly higher than Western countries2.The first Young Breast Cancer in China(YBCC)consensus meeting was held in Guangzhou,China in December 2021 to address exclusive challenges and requirements facing young patients with breast cancer.Chinese medical experts from multiple specialties had an extensive discussion and formulated a consensus over several hot topics in young patients with breast cancer.The“Expert Consensus on the Diagnosis and Treatment of Young Breast Cancer in China(2022 edition)”published in the Chinese Medical Journal has garnered significant attention3,highlighting enormous interest in the YBCC consensus in the medical community and public.展开更多
Kidney transplantation(KT)accounts for nearly three-fourths of organ transplants in India,with living donors contributing to 82%of cases.Induction immunosuppression is essential to optimize initial immunosuppression,r...Kidney transplantation(KT)accounts for nearly three-fourths of organ transplants in India,with living donors contributing to 82%of cases.Induction immunosuppression is essential to optimize initial immunosuppression,reduce acute rejections,and enable tailored use of maintenance agents.Rabbit anti-thymocyte globulin(rATG)and interleukin-2 receptor anatagonists(IL-2RA/IL-2RBs)are the most widely used induction therapies.However,data on induction practices across India are limited.To evaluate induction immunosuppression practices across KT centers in India and establish a consensus for different subsets of KT recipients.A nationwide online survey was conducted by the Indian Society of Organ Transplantation(ISOT)among its members(400 KT centers).Responses were analyzed to assess induction practices across diverse donor types,age groups,and immunological risk profiles.Heterogeneity in practices prompted consensus building using a modified Delphi process.Literature review and expert panel discussions(April 2024)were followed by structured voting,and 16 consensus statements were finalized.Of 400 centers approached,254 participated.rATG was the most commonly used induction therapy,followed by IL-2RBs;alemtuzumab was least used.Significant heterogeneity was observed in type,dose,and duration of induction therapy.Consensus recommendations were framed:rATG for high immunological risk recipients and deceased donor KTs;IL-2RB or low-dose rATG for low immunological risk;rituximab in ABOincompatible KTs;and tailoring based on age,diabetes,donor type,infection risk,and affordability.This first ISOT consensus provides 16 India-specific statements on induction therapy in KT.It emphasizes risk-stratified,evidenceinformed,and context-appropriate induction strategies,supporting standardization of care across the country.展开更多
This paper studies the problem of fixed-time output consensus tracking for high-order multi-agent systems(MASs)with directed network topology with consideration of data packet dropout.First,a predictive compensation b...This paper studies the problem of fixed-time output consensus tracking for high-order multi-agent systems(MASs)with directed network topology with consideration of data packet dropout.First,a predictive compensation based distributed observer is presented to compensate for packet dropout and estimate the leader’s states.Next,stability analysis is conducted to prove fixed time convergence of the developed distributed observer.Then,adaptive fixed-time dynamic surface control is designed to counteract mismatched disturbances introduced by observation error,and stabilize the tracking error system within a fixed time,which overcomes explosion of complexity problem and singularity problem.Finally,simulation results are provided to verify the effectiveness and superiority of the consensus tracking strategy proposed.The contribution of this paper is to provide a fixed-time distributed observer design method for high-order MAS under directed graph subject to packet dropout,and a novel fixed-time control strategy which can handle mismatched disturbances and overcome explosion of complexity and singularity problem.展开更多
The problem of fixed-time group consensus for second-order multi-agent systems with disturbances is investigated.For cooperative-competitive network,two different control protocols,fixed-time group consensus and fixed...The problem of fixed-time group consensus for second-order multi-agent systems with disturbances is investigated.For cooperative-competitive network,two different control protocols,fixed-time group consensus and fixed-time eventtriggered group consensus,are designed.It is demonstrated that there is no Zeno behavior under the designed eventtriggered control.Meanwhile,it is proved that for an arbitrary initial state of the system,group consensus within the settling time could be obtained under the proposed control protocols by using matrix analysis and graph theory.Finally,a series of numerical examples are propounded to illustrate the performance of the proposed control protocol.展开更多
In this paper,fixed-time consensus tracking for mul-tiagent systems(MASs)with dynamics in the form of strict feed-back affine nonlinearity is addressed.A fixed-time antidistur-bance consensus tracking protocol is prop...In this paper,fixed-time consensus tracking for mul-tiagent systems(MASs)with dynamics in the form of strict feed-back affine nonlinearity is addressed.A fixed-time antidistur-bance consensus tracking protocol is proposed,which consists of a distributed fixed-time observer,a fixed-time disturbance observer,a nonsmooth antidisturbance backstepping controller,and the fixed-time stability analysis is conducted by using the Lyapunov theory correspondingly.This paper includes three main improvements.First,a distributed fixed-time observer is developed for each follower to obtain an estimate of the leader’s output by utilizing the topology of the communication network.Second,a fixed-time disturbance observer is given to estimate the lumped disturbances for feedforward compensation.Finally,a nonsmooth antidisturbance backstepping tracking controller with feedforward compensation for lumped disturbances is designed.In order to mitigate the“explosion of complexity”in the tradi-tional backstepping approach,we have implemented a modified nonsmooth command filter to enhance the performance of the closed-loop system.The simulation results show that the pro-posed method is effective.展开更多
The research and development of new traditional Chinese medicine(TCM)drugs have progressively established a novel system founded on the integration of TCM theory,human experience,and clinical trials(termed the“Three ...The research and development of new traditional Chinese medicine(TCM)drugs have progressively established a novel system founded on the integration of TCM theory,human experience,and clinical trials(termed the“Three Combinations”).However,considering TCM's distinctive features of“syndrome differentiation and treatment”and“multicomponent formulations and complex mechanisms”,current TCM drug development faces challenges such as insufficient understanding of the material basis and the overall mechanism of action and an incomplete evidence chain system.Moreover,significant obstacles persist in gathering human experience data,evaluating clinical efficacy,and controlling the quality of active ingredients,which impede the innovation process in TCM drug development.Network pharmacology,centered on the“network targets”theory,transcends the limitations of the conventional“single target”reductionist research model.It emphasizes the comprehensive effects of disease or syndrome biological networks as targets to elucidate the overall regulatory mechanism of TCM prescriptions.This approach aligns with the holistic perspective of TCM,offering a novel method consistent with TCM's holistic view for investigating the complex mechanisms of TCM and developing new TCM drugs.It is internationally recognized as a“next-generation drug research model”.To advance the research of new tools,methods,and standards for TCM evaluation and to overcome fundamental,critical,and cutting-edge technical challenges in TCM regulation,this consensus aims to explore the characteristics,progress,challenges,applicable pathways,and specific applications of network pharmacology as a new theory,method,and tool in TCM drug development.The goal is to enhance the quality of TCM drug research and development and accelerate the efficiency of developing new TCM products.展开更多
The Internet of Things(IoT)has gained substantial attention in both academic research and real-world applications.The proliferation of interconnected devices across various domains promises to deliver intelligent and ...The Internet of Things(IoT)has gained substantial attention in both academic research and real-world applications.The proliferation of interconnected devices across various domains promises to deliver intelligent and advanced services.However,this rapid expansion also heightens the vulnerability of the IoT ecosystem to security threats.Consequently,innovative solutions capable of effectively mitigating risks while accommodating the unique constraints of IoT environments are urgently needed.Recently,the convergence of Blockchain technology and IoT has introduced a decentralized and robust framework for securing data and interactions,commonly referred to as the Internet of Blockchained Things(IoBT).Extensive research efforts have been devoted to adapting Blockchain technology to meet the specific requirements of IoT deployments.Within this context,consensus algorithms play a critical role in assessing the feasibility of integrating Blockchain into IoT ecosystems.The adoption of efficient and lightweight consensus mechanisms for block validation has become increasingly essential.This paper presents a comprehensive examination of lightweight,constraint-aware consensus algorithms tailored for IoBT.The study categorizes these consensus mechanisms based on their core operations,the security of the block validation process,the incorporation of AI techniques,and the specific applications they are designed to support.展开更多
Early correction of childhood malocclusion is timely managing morphological,structural,and functional abnormalities at different dentomaxillofacial developmental stages.The selection of appropriate imaging examination...Early correction of childhood malocclusion is timely managing morphological,structural,and functional abnormalities at different dentomaxillofacial developmental stages.The selection of appropriate imaging examination and comprehensive radiological diagnosis and analysis play an important role in early correction of childhood malocclusion.This expert consensus is a collaborative effort by multidisciplinary experts in dentistry across the nation based on the current clinical evidence,aiming to provide general guidance on appropriate imaging examination selection,comprehensive and accurate imaging assessment for early orthodontic treatment patients.展开更多
Patients with periodontal disease often require combined periodontal-orthodontic interventions to restore periodontal health,function,and aesthetics,ensuring both patient satisfaction and long-term stability.Managing ...Patients with periodontal disease often require combined periodontal-orthodontic interventions to restore periodontal health,function,and aesthetics,ensuring both patient satisfaction and long-term stability.Managing these patients involving orthodontic tooth movement can be particularly challenging due to compromised periodontal soft and hard tissues,especially in severe cases.Therefore,close collaboration between orthodontists and periodontists for comprehensive diagnosis and sequential treatment,along with diligent patient compliance throughout the entire process,is crucial for achieving favorable treatment outcomes.Moreover,long-term orthodontic retention and periodontal follow-up are essential to sustain treatment success.This expert consensus,informed by the latest clinical research and practical experience,addresses clinical considerations for orthodontic treatment of periodontal patients,delineating indications,objectives,procedures,and principles with the aim of providing clear and practical guidance for clinical practitioners.展开更多
This paper presents an investigation on the target-guided coordinated control(TACC)of unmanned surface vehicles(USVs).In the scenario of tracking non-cooperative targets,the status information of the target can only b...This paper presents an investigation on the target-guided coordinated control(TACC)of unmanned surface vehicles(USVs).In the scenario of tracking non-cooperative targets,the status information of the target can only be obtained by some USVs.In order to achieve semi-encirclement tracking of noncooperative targets under maritime security conditions,a fixed-time tracking control method based on dynamic surface control(DSC)is proposed in this paper.Firstly,a novel TACC architecture with decoupled kinematic control law and decoupled kinetic control law was designed to reduce the complexity of control system design.Secondly,the proposed DSC-based target-guided kinematic control law including tracking points pre-allocation strategy and sigmoid artificial potential functions(SigAPFs)can avoid collisions during tracking process and optimize kinematic control output.Finally,a fixed-time TACC system was proposed to achieve fast convergence of kinematic and kinetics errors.The effectiveness of the proposed TACC approach in improving target tracking safety and reducing control output chattering was verified by simulation comparison results.展开更多
基金supported in part by the National Natural Science Foundation of China (62073108)the Zhejiang Provincial Natural Science Foundation(LZ23F030004)+1 种基金the Key Research and Development Project of Zhejiang Province (2019C04018)the Fundamental Research Funds for the Provincial Universities of Zhejiang (GK229909299001-004)。
文摘This article deals with the consensus problem of multi-agent systems by developing a fixed-time consensus control approach with a dynamic event-triggered rule. First, a new fixedtime stability condition is obtained where the less conservative settling time is given such that the theoretical settling time can well reflect the real consensus time. Second, a dynamic event-triggered rule is designed to decrease the use of chip and network resources where Zeno behaviors can be avoided after consensus is achieved, especially for finite/fixed-time consensus control approaches. Third, in terms of the developed dynamic event-triggered rule, a fixed-time consensus control approach by introducing a new item is proposed to coordinate the multi-agent system to reach consensus. The corresponding stability of the multi-agent system with the proposed control approach and dynamic eventtriggered rule is analyzed based on Lyapunov theory and the fixed-time stability theorem. At last, the effectiveness of the dynamic event-triggered fixed-time consensus control approach is verified by simulations and experiments for the problem of magnetic map construction based on multiple mobile robots.
基金National Natural Science Foundation of China(No.62073296)Natural Science Foundation of Zhejiang Province,China(No.LZ23F030010)Key Laboratory of Intelligent Manufacturing Quality Big Data Tracing and Analysis of Zhejiang Province,China Jiliang University(No.ZNZZSZ-CJLU2022-03)Rights and permissions。
文摘To address fixed-time consensus problems of a class of leader-follower second-order nonlinear multi-agent systems with uncertain external disturbances,the event-triggered fixed-time consensus protocol is proposed.First,the virtual velocity is designed based on the backstepping control method to achieve the system consensus and the bound on convergence time only depending on the system parameters.Second,an event-triggered mechanism is presented to solve the problem of frequent communication between agents,and triggered condition based on state information is given for each follower.It is available to save communication resources,and the Zeno behaviors are excluded.Then,the delay and switching topologies of the system are also discussed.Next,the system stabilization is analyzed by Lyapunov stability theory.Finally,simulation results demonstrate the validity of the presented method.
基金Supported by the National Natural Science Foundation of China(11401577,11671011)
文摘We analyse the fixed-time consensus problem for multi-agent systems with leaderfollower mode. Based on a follower’s observation structure for the leader’s information, it is proved that the estimation errors can be converged to zero at a fixed time. From this stability and a sliding mode structure, we derive a control input of followers, which provides a critical support for fixed-time consensus. The simulation results demonstrate that this control approach does conduce to the implementation of the fixed-time synchronization.
基金supported by the National Natural Science Foundation of China(62203356).
文摘In this paper,the problem of non-singular fixed-time control with prescribed performance is studied for multi-agent systems characterized by uncertain states,nonlinearities,and nonstrict feedback.To mitigate the nonlinearity,a fuzzy logic algorithm is applied to approximate the intrinsic dynamics of the system.Furthermore,a fuzzy logic system state observer based on leader state information is designed to address the partial unob-servability of followers.Subsequently,the power integral method is incorporated into the backstepping approach to avoid singularities in the fixed-time controller.A command filter method is introduced into the standard backstepping approach to reduce the computational complexity of controller design.Then,a non-singular fixed-time adaptive control strategy with prescribed performance is proposed by constraining the tracking error within a prescribed range.Rigorous theoretical analysis ensures the convergence of consensus error in the multi-agent system to the prescribed performance region within a fixed time.Finally,the practicality of the algorithm is validated through numerical simulations.
基金supported by the National Natural Science Foundation of China(61673130).
文摘This paper investigates the sliding-mode-based fixed-time distributed average tracking (DAT) problem for multiple Euler-Lagrange systems in the presence of external distur-bances. The primary objective is to devise controllers for each agent, enabling them to precisely track the average of multiple time-varying reference signals. By averaging these signals, we can mitigate the influence of errors and uncertainties arising dur-ing measurements, thereby enhancing the robustness and stabi-lity of the system. A distributed fixed-time average estimator is proposed to estimate the average value of global reference sig-nals utilizing local information and communication with neigh-bors. Subsequently, a fixed-time sliding mode controller is intro-duced incorporating a state-dependent sliding mode function coupled with a variable exponent coefficient to achieve dis-tributed average tracking of reference signals, and rigorous ana-lytical methods are employed to substantiate the fixed-time sta-bility. Finally, numerical simulation results are provided to vali-date the effectiveness of the proposed methodology, offering insights into its practical application and robust performance.
文摘Background:Insufficient physical activity and prolonged sedentary behavior have emerged as major global public health challenges.Short bouts(≤10 min)of accumulated exercise(SBAE)throughout the day may be a promising strategy to mitigate the adverse effects of prolonged sitting and promote physical activity,ultimately promoting overall health.However,previous ambiguity in defining this concept has resulted in a fragmented and inconsistent evidence base,impeding practical applications,the development of guidelines,and policymaking.The purpose of this study is to establish an operational definition of SBAE by synthesizing systematic reviews and research trials alongside an expert consensus.Additionally,it seeks to evaluate acute and long-term efficacy and feasibility,providing evidence-based recommendations for practice and future research directions.Methods:A literature search was performed across PubMed and Web of Science,followed by systematic screening and summarization of eligible studies based on predefined inclusion criteria.Inclusion criteria encompassed various modes/types of SBAE(bouts lasting≤10 min,performed multiple times daily with≥30 min intervals);both aerobic and resistance exercise were considered.Relevant systematic reviews and research trials were included.Methodological quality,risk of bias,and evidence certainty were assessed.Expert consensus was obtained through a survey to evaluate recommendations and agreement levels on findings.Results:After analyzing 27 systematic reviews,135 research studies,and an expert consensus involving 48 researchers from 11 countries,SBAE is defined as any exercise mode of activity,regardless of intensity,that is accumulated in either continuous or intermittent bouts lasting≤10 min per session(including multiple intermittent sets)that are performed multiple times(≥2 sessions/day)per day,with intervals of≥30 min between bouts or otherwise sufficient time for recovery.When used to interrupt prolonged periods of sedentary time,SBAE mitigates the acute adverse effects of sedentary behavior on more than 10 clinical biomarkers of endocrine,cardiovascular,and brain health/function among adults of diverse ages and conditions.Moreover,SBAE was superior for improving acute glycemic control compared to a single continuous exercise session.As a long-term intervention(average of 11 weeks),SBAE can improve over 20 health outcomes,including peak oxygen uptake,resting blood pressure,and metabolic health.Additionally,SBAE might be more effective than continuous exercise for improving longer-term glycemic control and body composition.Long-term completion rates for SBAE interventions are generally high(95%),with low dropout rates(12%)and high adherence rates even without supervision(85%),and its safety has been preliminarily validated.Conclusion:An operational definition of SBAE is provided along with its classification and acute and long-term efficacy.Practical exercise prescription recommendations and evidence-based strategies for various populations and contexts are provided.Future research should focus on generating high-quality evidence for SBAE in 5 key areas:quantification and monitoring,population-specific responses,optimization of exercise prescriptions,intervention efficacy,and practical implementation.Additionally,addressing policy,environmental,and promotional barriers is crucial for transitioning from expert consensus to public consensus,and for facilitating the application of this strategy in real-world environments.
基金supported by the National Natural Science Foundation of China(62373317)the Tianshan Talent Training Program(2022TSYCCX0013)+3 种基金the Key Project of Natural Science Foundation of Xinjiang(2021D01D10)the Basic Research Foundation for Universities of Xinjiang(XJEDU2023P023)the Xinjiang Key Laboratory of Applied Mathematics(XJDX1401)the Intelligent Control and Optimization Research Platform in Xinjiang University.
文摘This paper is dedicated to fixed-time passivity and synchronization for multi-weighted spatiotemporal directed networks.First,to achieve fixed-time passivity,a type of decentralized power-law controller is developed,in which only one parameter needs to be adjusted in the power-law terms;this greatly decreases the inconvenience of parameter adjustment.Second,several fixed-time passivity criteria with LMI forms are derived by using a Gauss divergence theorem to deal with the spatial diffusion of nodes and by applying the Hölder’s inequality to dispose rigorously the power-law term greater than one in the designed control scheme;this improves the previous theoretical analysis.Additionally,the fixed-time synchronization of spatiotemporal directed networks with multi-weights is addressed as a direct result of fixed-time strict passivity.Finally,a numerical example is presented in order to show the validity of the theoretical analysis.
基金supported in part by Beijing Natural Science Foundation(L244010,251038)National Natural Science Foundation of China(92467203,62372050,62502041)+2 种基金CCF-Huawei Populus Grove Fund(TC202418)Fellowship of China National Postdoctoral Program for Innovative Talents(BX20240045)China Postdoctoral Science Foundation General Program(2025M773481).
文摘Practical byzantine fault tolerance(PBFT)can reduce energy consumption and achieve high throughput compared with the traditional PoW algorithm,which is more suitable for a strongly consistent consortium blockchain.However,due to the frequent communication among nodes,PBFT cannot realize scalability in large-scale networks.Existing PBFTbased algorithms still ignore performance and security.Therefore,we propose a secure and efficient practical byzantine fault tolerance based on double layers and multi copies(DM-PBFT).We design a reputation evaluation and node scheduling method for DMPBFT.And then we propose an adaptive node scheduling strategy based on the derived threshold values after analyzing the system communication complexity and security.Combining the above research,a node dynamic adjustment mechanism is proposed to freeze or adjust the node operation status according to the system environment.Simulation experiments show that the proposed mechanism can improve efficiency and increase the system’s throughput.
基金supported by the National Natural Science Foundation of China(Grant No.61762071,Grant No.61163025).
文摘The Internet of Vehicles(IoV)operates in highly dynamic and open network environments and faces serious challenges in secure and real-time authentication and consensus mechanisms.Existing methods often suffer from complex certificate management,inefficient consensus protocols,and poor resilience in high-frequency communication,resulting in high latency,poor scalability,and unstable network performance.To address these issues,this paper proposes a secure and efficient distributed authentication scheme for IoV with reputation-driven consensus and SM9.First,this paper proposes a decentralized authentication architecture that utilizes the certificate-free feature of SM9,enabling lightweight authentication and key negotiation,thereby reducing the complexity of key management.To ensure the traceability and global consistency of authentication data,this scheme also integrates blockchain technology,applying its inherent invariance.Then,this paper introduces a reputation-driven dynamic node grouping mechanism that transparently evaluates and groups’node behavior using smart contracts to enhance network stability.Furthermore,a new RBSFT(Reputation-Based SM9 Friendly-Tolerant)consensus mechanism is proposed for the first time to enhance consensus efficiency by optimizing the PBFT algorithm.RBSFT aims to write authentication information into the blockchain ledger to achieve multi-level optimization of trust management and decision-making efficiency,thereby significantly improving the responsiveness and robustness in high-frequency IoV scenarios.Experimental results show that it excels in authentication,communication efficiency,and computational cost control,making it a feasible solution for achieving IoV security and real-time performance.
基金supported by the National Natural Science Foundation of China(62463007,62463005)the Natural Science Foundation of Hainan Province(625RC710,625MS047)+1 种基金the System Control and Information Processing Education Ministry Key Laboratory Open Funding,China(Scip20240119)the Science Research Funding of Hainan University,China(KYQD(ZR)22180,KYQD(ZR)23180).
文摘This paper focuses on the leader-following positive consensus problems of heterogeneous switched multi-agent systems.First,a state-feedback controller with dynamic compensation is introduced to achieve positive consensus under average dwell time switching.Then sufficient conditions are derived to guarantee the positive consensus.The gain matrices of the control protocol are described using a matrix decomposition approach and the corresponding computational complexity is reduced by resorting to linear programming and co-positive Lyapunov functions.Finally,two numerical examples are provided to illustrate the results obtained.
基金supported by the National Natural Science Foundation of China(Grant Nos.82230057 and 82272859)the National Key R&D Program of China(Grant No.2022YFC2505101).
文摘Introduction,Breast cancer is the most common cancer type in adolescents and young adults<40 years of age,accounting for 30%of cancers in this age group1.Breast cancer in the young presents significant challenges for patients and society,including more aggressive tumor biology,poor prognosis,genetic susceptibility,fertility preservation,and complex psychosocial issues.Moreover,because of the markedly younger median age of breast cancer,the proportion of young breast cancer patients in China is significantly higher than Western countries2.The first Young Breast Cancer in China(YBCC)consensus meeting was held in Guangzhou,China in December 2021 to address exclusive challenges and requirements facing young patients with breast cancer.Chinese medical experts from multiple specialties had an extensive discussion and formulated a consensus over several hot topics in young patients with breast cancer.The“Expert Consensus on the Diagnosis and Treatment of Young Breast Cancer in China(2022 edition)”published in the Chinese Medical Journal has garnered significant attention3,highlighting enormous interest in the YBCC consensus in the medical community and public.
文摘Kidney transplantation(KT)accounts for nearly three-fourths of organ transplants in India,with living donors contributing to 82%of cases.Induction immunosuppression is essential to optimize initial immunosuppression,reduce acute rejections,and enable tailored use of maintenance agents.Rabbit anti-thymocyte globulin(rATG)and interleukin-2 receptor anatagonists(IL-2RA/IL-2RBs)are the most widely used induction therapies.However,data on induction practices across India are limited.To evaluate induction immunosuppression practices across KT centers in India and establish a consensus for different subsets of KT recipients.A nationwide online survey was conducted by the Indian Society of Organ Transplantation(ISOT)among its members(400 KT centers).Responses were analyzed to assess induction practices across diverse donor types,age groups,and immunological risk profiles.Heterogeneity in practices prompted consensus building using a modified Delphi process.Literature review and expert panel discussions(April 2024)were followed by structured voting,and 16 consensus statements were finalized.Of 400 centers approached,254 participated.rATG was the most commonly used induction therapy,followed by IL-2RBs;alemtuzumab was least used.Significant heterogeneity was observed in type,dose,and duration of induction therapy.Consensus recommendations were framed:rATG for high immunological risk recipients and deceased donor KTs;IL-2RB or low-dose rATG for low immunological risk;rituximab in ABOincompatible KTs;and tailoring based on age,diabetes,donor type,infection risk,and affordability.This first ISOT consensus provides 16 India-specific statements on induction therapy in KT.It emphasizes risk-stratified,evidenceinformed,and context-appropriate induction strategies,supporting standardization of care across the country.
基金supported in part by the National Natural Science Foundation of China(61903302,61973252,61903126)the Natural Science Basic Research Plan in Shaanxi Province of China(2019JQ-035)+2 种基金the Fundamental Research Funds for the Central Universities(31020180QD076,ZDHXYKYYW201914)Key R&D and Promotion Projects in Henan Province(202102210130)Key Scientific Research Projects of Universities in Henan Province-20A590001。
文摘This paper studies the problem of fixed-time output consensus tracking for high-order multi-agent systems(MASs)with directed network topology with consideration of data packet dropout.First,a predictive compensation based distributed observer is presented to compensate for packet dropout and estimate the leader’s states.Next,stability analysis is conducted to prove fixed time convergence of the developed distributed observer.Then,adaptive fixed-time dynamic surface control is designed to counteract mismatched disturbances introduced by observation error,and stabilize the tracking error system within a fixed time,which overcomes explosion of complexity problem and singularity problem.Finally,simulation results are provided to verify the effectiveness and superiority of the consensus tracking strategy proposed.The contribution of this paper is to provide a fixed-time distributed observer design method for high-order MAS under directed graph subject to packet dropout,and a novel fixed-time control strategy which can handle mismatched disturbances and overcome explosion of complexity and singularity problem.
基金Project supported by the Graduate Student Research Innovation Project of Chongqing(Grant No.CYS22482)the National Natural Science Foundation of China(Grant No.61773082)+1 种基金the Science and Technology Research Program of Chongqing Municipal Education Commission(Grant No.KJZD-K202000601)the Research Program of Chongqing Talent,China(Grant No.cstc2021ycjhbgzxm0044).
文摘The problem of fixed-time group consensus for second-order multi-agent systems with disturbances is investigated.For cooperative-competitive network,two different control protocols,fixed-time group consensus and fixed-time eventtriggered group consensus,are designed.It is demonstrated that there is no Zeno behavior under the designed eventtriggered control.Meanwhile,it is proved that for an arbitrary initial state of the system,group consensus within the settling time could be obtained under the proposed control protocols by using matrix analysis and graph theory.Finally,a series of numerical examples are propounded to illustrate the performance of the proposed control protocol.
基金supported by the National Defense Basic Scientific Research Project(JCKY2020130C025)the National Science and Technology Major Project(J2019-III-0020-0064,J2019-V-0014-0109)。
文摘In this paper,fixed-time consensus tracking for mul-tiagent systems(MASs)with dynamics in the form of strict feed-back affine nonlinearity is addressed.A fixed-time antidistur-bance consensus tracking protocol is proposed,which consists of a distributed fixed-time observer,a fixed-time disturbance observer,a nonsmooth antidisturbance backstepping controller,and the fixed-time stability analysis is conducted by using the Lyapunov theory correspondingly.This paper includes three main improvements.First,a distributed fixed-time observer is developed for each follower to obtain an estimate of the leader’s output by utilizing the topology of the communication network.Second,a fixed-time disturbance observer is given to estimate the lumped disturbances for feedforward compensation.Finally,a nonsmooth antidisturbance backstepping tracking controller with feedforward compensation for lumped disturbances is designed.In order to mitigate the“explosion of complexity”in the tradi-tional backstepping approach,we have implemented a modified nonsmooth command filter to enhance the performance of the closed-loop system.The simulation results show that the pro-posed method is effective.
基金supported by the National Medical Products Administration Commissioned Research Project (No.20211440216)the National Administration of Traditional Chinese Medicine Science and Technology Project (No.GZY-KJS-2024-03)+3 种基金the State Key Laboratory of Drug Regulatory Science Project (No.2023SKLDRS0104)the Basic Research Program Natural Science Fund-Frontier Leading Technology Basic Research Special Project of Jiangsu Province (No.BK20232014)the Programs Foundation for Leading Talents in National Administration of Traditional Chinese Medicine of China“Qihuang scholars”Projectthe Tianjin Administration for Market Regulation Science and Technology Key Projects (No.2022-W35)。
文摘The research and development of new traditional Chinese medicine(TCM)drugs have progressively established a novel system founded on the integration of TCM theory,human experience,and clinical trials(termed the“Three Combinations”).However,considering TCM's distinctive features of“syndrome differentiation and treatment”and“multicomponent formulations and complex mechanisms”,current TCM drug development faces challenges such as insufficient understanding of the material basis and the overall mechanism of action and an incomplete evidence chain system.Moreover,significant obstacles persist in gathering human experience data,evaluating clinical efficacy,and controlling the quality of active ingredients,which impede the innovation process in TCM drug development.Network pharmacology,centered on the“network targets”theory,transcends the limitations of the conventional“single target”reductionist research model.It emphasizes the comprehensive effects of disease or syndrome biological networks as targets to elucidate the overall regulatory mechanism of TCM prescriptions.This approach aligns with the holistic perspective of TCM,offering a novel method consistent with TCM's holistic view for investigating the complex mechanisms of TCM and developing new TCM drugs.It is internationally recognized as a“next-generation drug research model”.To advance the research of new tools,methods,and standards for TCM evaluation and to overcome fundamental,critical,and cutting-edge technical challenges in TCM regulation,this consensus aims to explore the characteristics,progress,challenges,applicable pathways,and specific applications of network pharmacology as a new theory,method,and tool in TCM drug development.The goal is to enhance the quality of TCM drug research and development and accelerate the efficiency of developing new TCM products.
文摘The Internet of Things(IoT)has gained substantial attention in both academic research and real-world applications.The proliferation of interconnected devices across various domains promises to deliver intelligent and advanced services.However,this rapid expansion also heightens the vulnerability of the IoT ecosystem to security threats.Consequently,innovative solutions capable of effectively mitigating risks while accommodating the unique constraints of IoT environments are urgently needed.Recently,the convergence of Blockchain technology and IoT has introduced a decentralized and robust framework for securing data and interactions,commonly referred to as the Internet of Blockchained Things(IoBT).Extensive research efforts have been devoted to adapting Blockchain technology to meet the specific requirements of IoT deployments.Within this context,consensus algorithms play a critical role in assessing the feasibility of integrating Blockchain into IoT ecosystems.The adoption of efficient and lightweight consensus mechanisms for block validation has become increasingly essential.This paper presents a comprehensive examination of lightweight,constraint-aware consensus algorithms tailored for IoBT.The study categorizes these consensus mechanisms based on their core operations,the security of the block validation process,the incorporation of AI techniques,and the specific applications they are designed to support.
基金supports by the National Natural Science Foundation of China(Nos.82201135)"2015"Cultivation Program for Reserve Talents for Academic Leaders of Nanjing Stomatological School,Medical School of Nanjing University(No.0223A204).
文摘Early correction of childhood malocclusion is timely managing morphological,structural,and functional abnormalities at different dentomaxillofacial developmental stages.The selection of appropriate imaging examination and comprehensive radiological diagnosis and analysis play an important role in early correction of childhood malocclusion.This expert consensus is a collaborative effort by multidisciplinary experts in dentistry across the nation based on the current clinical evidence,aiming to provide general guidance on appropriate imaging examination selection,comprehensive and accurate imaging assessment for early orthodontic treatment patients.
基金supported by the National Key R&D Program of China(2022YFC2504200)Chongqing Young and Middle-aged Medical Excellence Team ProjectJiangsu Province Key Research and Development Program(BE2022670)。
文摘Patients with periodontal disease often require combined periodontal-orthodontic interventions to restore periodontal health,function,and aesthetics,ensuring both patient satisfaction and long-term stability.Managing these patients involving orthodontic tooth movement can be particularly challenging due to compromised periodontal soft and hard tissues,especially in severe cases.Therefore,close collaboration between orthodontists and periodontists for comprehensive diagnosis and sequential treatment,along with diligent patient compliance throughout the entire process,is crucial for achieving favorable treatment outcomes.Moreover,long-term orthodontic retention and periodontal follow-up are essential to sustain treatment success.This expert consensus,informed by the latest clinical research and practical experience,addresses clinical considerations for orthodontic treatment of periodontal patients,delineating indications,objectives,procedures,and principles with the aim of providing clear and practical guidance for clinical practitioners.
文摘This paper presents an investigation on the target-guided coordinated control(TACC)of unmanned surface vehicles(USVs).In the scenario of tracking non-cooperative targets,the status information of the target can only be obtained by some USVs.In order to achieve semi-encirclement tracking of noncooperative targets under maritime security conditions,a fixed-time tracking control method based on dynamic surface control(DSC)is proposed in this paper.Firstly,a novel TACC architecture with decoupled kinematic control law and decoupled kinetic control law was designed to reduce the complexity of control system design.Secondly,the proposed DSC-based target-guided kinematic control law including tracking points pre-allocation strategy and sigmoid artificial potential functions(SigAPFs)can avoid collisions during tracking process and optimize kinematic control output.Finally,a fixed-time TACC system was proposed to achieve fast convergence of kinematic and kinetics errors.The effectiveness of the proposed TACC approach in improving target tracking safety and reducing control output chattering was verified by simulation comparison results.
