Based on the discrete mechanics and optimal control framework,Hamel’s variational integrators are employed to solve the fuel-optimal and time-optimal control problems for a single rigid body.The optimal control probl...Based on the discrete mechanics and optimal control framework,Hamel’s variational integrators are employed to solve the fuel-optimal and time-optimal control problems for a single rigid body.The optimal control problem is discretized via the discrete d’Alembert-Lagrange principle,and the corresponding discrete necessary conditions for optimality are derived.The sensitivity matrix is constructed and solved using the Newton-Armijo iteration method.This approach effectively linearizes the nonlinear problem,enhancing computational efficiency and ease of implementation.Finally,two numerical examples involving the optimal control of spacecraft orbital transfers are presented to verify the effectiveness and applicability of the proposed method.展开更多
The variational integrators of autonomous Birkhoff systems are obtained by the discrete variational principle. The geometric structure of the discrete autonomous Birkhoff system is formulated. The discretization of ma...The variational integrators of autonomous Birkhoff systems are obtained by the discrete variational principle. The geometric structure of the discrete autonomous Birkhoff system is formulated. The discretization of mathematical pendulum shows that the discrete variational method is as effective as symplectic scheme for the autonomous Birkhoff systems.展开更多
Integrator based model is used to describe a wide range of systems in robotics. In this paper, we present an axis-coupled trajectory generation algorithm for chains of integrators with an arbitrary order. Special noti...Integrator based model is used to describe a wide range of systems in robotics. In this paper, we present an axis-coupled trajectory generation algorithm for chains of integrators with an arbitrary order. Special notice has been given to problems with pre-existing nominal plans, which are common in robotic applications. It also handles various type of constraints that can be satisfied on an entire time interval, including non-convex ones which can be transformed into a series of convex constraints through time segmentation. The proposed approach results in a linearly constrained quadratic programming problem, which can be solved effectively with off-the-shelf solvers. A closed-form solution is achievable with only the boundary constraints considered. Finally, the proposed method is tested in real experiments using quadrotors which represent high-order integrator systems.展开更多
In this paper, we propose a variational integrator for nonlinear Schrodinger equations with variable coefficients. It is shown that our variational integrator is naturally multi-symplectic. The discrete multi-symplect...In this paper, we propose a variational integrator for nonlinear Schrodinger equations with variable coefficients. It is shown that our variational integrator is naturally multi-symplectic. The discrete multi-symplectic structure of the integrator is presented by a multi-symplectic form formula that can be derived from the discrete Lagrangian boundary function. As two examples of nonlinear Schrodinger equations with variable coefficients, cubic nonlinear Schrodinger equations and Gross-Pitaevskii equations are extensively studied by the proposed integrator. Our numerical simulations demonstrate that the integrator is capable of preserving the mass, momentum, and energy conservation during time evolutions. Convergence tests are presented to verify that our integrator has second-order accuracy both in time and space.展开更多
This paper studies a distributed optimal consensus problem for multiple double integrators under bounded velocity and acceleration. Assigned with an in dividual and private convex cost which is dependent on the positi...This paper studies a distributed optimal consensus problem for multiple double integrators under bounded velocity and acceleration. Assigned with an in dividual and private convex cost which is dependent on the position, each age nt n eeds to achieve consensus at the optimum of the aggregate cost under bounded velocity and acceleration. Based on relative positions and velocities to neighbor agents, we design a distributed control law by including the integration feedback of position and velocity errors. By employing quadratic Lyapunov functions, we solve the optimal consensus problem of double-integrators when the fixed topology is strongly connected and weight-balanced. Furthermore, if an initial estimate of the optimum can be known, then control gains can be properly selected to achieve an exponentially fast convergence under bounded velocity and acceleration. The result still holds when the relative velocity is not available, and we also discuss an extension for heterogeneous Euler-Lagrange systems by in verse dynamics control. A nu meric example is provided to illustrate the result.展开更多
A discrete total variation calculus with variable time steps is presented for mechanico-electrical systems where there exist non-potential and dissipative forces. By using this discrete variation calculus, the symplec...A discrete total variation calculus with variable time steps is presented for mechanico-electrical systems where there exist non-potential and dissipative forces. By using this discrete variation calculus, the symplectic-energy-first integrators for mechanico-electrical systems are derived. To do this, the time step adaptation is employed. The discrete variational principle and the Euler-Lagrange equation are derived for the systems. By using this discrete algorithm it is shown that mechanico-electrical systems are not symplectic and their energies are not conserved unless they are Lagrange mechanico-electrical systems. A practical example is presented to illustrate these results.展开更多
Two new fourth-order three-stage symplectic integrators are specifically designed for a family of Hamiltonian systems,such as the harmonic oscillator,mathematical pendulum and latticeφ4 model.When the nonintegrable l...Two new fourth-order three-stage symplectic integrators are specifically designed for a family of Hamiltonian systems,such as the harmonic oscillator,mathematical pendulum and latticeφ4 model.When the nonintegrable latticeφ4 system is taken as a test model,numerical comparisons show that the new methods have a great advantage over the second-order Verlet symplectic integrators in the accuracy of energy,become explicitly better than the usual non-gradient fourth-order seven-stage symplectic integrator of Forest and Ruth,and are almost equivalent to a fourth-order seven-stage force gradient symplectic integrator of Chin.As the most important advantage,the new integrators are convenient for solving the variational equations of many Hamiltonian systems so as to save a great deal of the computational cost when scanning a lot of orbits for chaos.展开更多
N-body simulations of the Sun, the planets, and small celestial bodies are frequently used to model the evolution of the Solar System. Large numbers of numerical integrators for performing such simulations have been d...N-body simulations of the Sun, the planets, and small celestial bodies are frequently used to model the evolution of the Solar System. Large numbers of numerical integrators for performing such simulations have been developed and used;see, for example, [1,2]. The primary objective of this paper is to analyse and compare the efficiency and the error growth for different numerical integrators. Throughout the paper, the error growth is examined in terms of the global errors in the positions and velocities, and the relative errors in the energy and angular momentum of the system. We performed numerical experiments for the different integrators applied to the Jovian problem over a long interval of duration, as long as one million years, with the local error tolerance ranging from 10-16 to 10-18.展开更多
Based on the Magnus integrator method established in linear dynamic systems, an efficiently improved modified Magnus integrator method was proposed for the second-order dynamic systems with time-dependent high frequen...Based on the Magnus integrator method established in linear dynamic systems, an efficiently improved modified Magnus integrator method was proposed for the second-order dynamic systems with time-dependent high frequencies. Firstly, the secondorder dynamic system was reformulated as the first-order system and the frame of reference was transfered by introducing new variables so that highly oscillatory behaviour inherits from the entries in the meantime. Then the modified Magnus integrator method based on local linearization was appropriately designed for solving the above new form and some improved also were presented. Finally, numerical examples show that the proposed methods appear to be quite adequate for integration for highly oscillatory dynamic systems including Hamiltonian systems problem with long time and effectiveness.展开更多
For the problem of set point regulation of the liquid level in coupled tank systems, we present a continuous sliding mode control(SMC) with a "conditional integrator", which only provides integral action ins...For the problem of set point regulation of the liquid level in coupled tank systems, we present a continuous sliding mode control(SMC) with a "conditional integrator", which only provides integral action inside the boundary layer. For a special choice of the controller parameters, our design can be viewed as a PID controller with anti-windup and achieves robust regulation.The proposed controller recovers the transient response performance without control chattering. Both full-state feedback as well as output-feedback designs are presented in this work. Our output-feedback design uses a high-gain observer(HGO) which recovers the performance of a state-feedback design where plant parameters are assumed to be known. We consider both interacting as well as non-interacting tanks and analytical results for stability and transient performance are presented in both the cases. The proposed controller continuous SMC with conditional integrators(CSMCCI) provides superior results in terms of the performance measures as well as performance indices than ideal SMC, continuous SMC(CSMC) and continuous SMC with conventional integrator(CSMCI). Experimental results demonstrate good tracking performance in spite of unmodeled dynamics and disturbances.展开更多
ZTE Corporation has signed strategic telecommunications software agreement with two leading providers in Europe and Latin America to optimize its offerings for target customers in
In this work,a consistent and physically accurate implementation of the general framework of unified second-order time accurate integrators via the well-known GSSSS framework in the Discrete Element Method is presente...In this work,a consistent and physically accurate implementation of the general framework of unified second-order time accurate integrators via the well-known GSSSS framework in the Discrete Element Method is presented.The improved tangential displacement evaluation in the present implementation of the discrete element method has been derived and implemented to preserve the consistency of the correct time level evaluation during the time integration process in calculating the algorithmic tangential displacement.Several numerical examples have been used to validate the proposed tangential displacement evaluation;this is in contrast to past practices which only seem to attain the first-order time accuracy due to inconsistent time level implementation with different algorithms for normal and tangential directions.The comparisons with the existing implementation and the superiority of the proposed implementation are given in terms of the convergence rate with improved numerical accuracy in time.Moreover,several schemes via the unified second-order time integrators within the framework of the GSSSS family have been carried out based on the proposed correct implementation.All the numerical results demonstrate that using the existing state-of-the-art implementation reduces the time accuracy to be first-order accurate in time,while the proposed implementation preserves the correct time accuracy to yield second-order.展开更多
This paper develops a new approach to construct variational integrators. A simplified unconventional Hamilton's variational principle corresponding to initial value problems is proposed, which is convenient for appli...This paper develops a new approach to construct variational integrators. A simplified unconventional Hamilton's variational principle corresponding to initial value problems is proposed, which is convenient for applications. The displacement and mo- mentum are approximated with the same Lagrange interpolation. After the numerical integration and variational operation, the original problems are expressed as algebraic equations with the displacement and momentum at the interpolation points as unknown variables. Some particular variational integrators are derived. An optimal scheme of choosing initial values for the Newton-Raphson method is presented for the nonlinear dynamic system. In addition, specific examples show that the proposed integrators are symplectic when the interpolation point coincides with the numerical integration point, and both are Gaussian quadrature points. Meanwhile, compared with the same order symplectic Runge-Kutta methods, although the accuracy of the two methods is almost the same, the proposed integrators are much simpler and less computationally expensive.展开更多
In this paper,the authors study the problem of distributed Nash equilibrium seeking of N-player games with high-order integrator dynamics subject to disturbances generated by an uncertain exosystem.Similar problems ha...In this paper,the authors study the problem of distributed Nash equilibrium seeking of N-player games with high-order integrator dynamics subject to disturbances generated by an uncertain exosystem.Similar problems have been studied for disturbances with an exactly known exosystem.Compared with the existing results of high-order integrator dynamics,which can only handle sinusoidal disturbances with known frequencies,this paper aims to handle multi-tone disturbances with unknown frequencies by introducing an adaptive control technique to estimate the unknown frequencies.Technically,when the exosystem is known,the disturbance can be dealt with by the Luenburger observer.In contrast,the Luenburger observer cannot deal with an uncertain exosystem.The authors combine the internal model design and some adaptive control technique to solve the proposed problem.Further,the authors also establish the sufficient condition to guarantee the convergence of the estimated unknown frequencies to the actual values of these frequencies.Two examples are given to verify the proposed algorithm.展开更多
Qingke,a staple crop grown on the high-altitude Tibetan Plateau,has evolved a metabolomic profile providing both environmental stress resilience and human nutrition.We review the hypothesis that the metabolites that c...Qingke,a staple crop grown on the high-altitude Tibetan Plateau,has evolved a metabolomic profile providing both environmental stress resilience and human nutrition.We review the hypothesis that the metabolites that confer cold and UV resistance on the crop also facilitate human adaptation to high-altitude stresses.Specifically,β-glucans regulate blood glucose primarily via short-chain fatty acids(SCFAs)produced through gut microbiota fermentation,which directly mediate glucose homeostasis.Phenolamides accumulate via the phenylpropanoid pathway,with chalcone isomerase(CHI)serving as a key enzyme in flavonoid biosynthesis and enhancing UV-B resistance.Under low temperatures,β-glucans improve frost tolerance by modulating osmotic balance and inhibiting ice-nucleating proteins,while lipids maintain membrane fluidity to sustain cellular function during cold stress.Importantly,we explore the hypothesis that these same metabolites,upon consumption,may facilitate human adaptation to high-altitude stresses.This hypothesis is supported by preliminary epidemiological associations between Qingke consumption and favorable health outcomes in high-altitude populations,as well as established bioactivities of the implicated metabolites in vitro and in animal models.However,direct causal evidence in humans and a comprehensive understanding of the underlying molecular mechanisms remain key knowledge gaps that warrant future investigation.Qingke as a unique resource at the interface of agricultural resilience and human nutrition.Understanding its metabolic blueprint will inform the development of functional foods and climate-resilient crops.展开更多
tRNA-derived small RNAs(tsRNAs),as a class of regulatory small noncoding RNA,have been implicated in a wide variety of human diseases.Large amounts of tsRNA–disease associations have been identified in recent years f...tRNA-derived small RNAs(tsRNAs),as a class of regulatory small noncoding RNA,have been implicated in a wide variety of human diseases.Large amounts of tsRNA–disease associations have been identified in recent years from accumulating studies.However,repositories for cataloging the detailed information on tsRNA–disease associations are scarce.In this study,we provide a tsRNADisease database by integrating experimentally and computationally supported tsRNA–disease associations from manual curation of literatures and other related resources.tsRNADisease contains 5571 manually curated associations between 4759 tsRNAs and 166 diseases with experimental evidence from 346 studies.In addition,it also contains 5013 predicted associations between 1297 tsRNAs and 111 diseases.tsRNADisease provides a user-friendly interface to browse,retrieve,and download data conveniently.This database can improve our understanding of tsRNA deregulation in diseases and serve as a valuable resource for investigating the mechanism of disease-related tsRNAs.tsRNADisease is freely available at http://gffzz9c504e06f78b4edahnoffqqoc9qvf6ucx.ffgz.tsg.suse.edu.cn.展开更多
Alzheimer's disease is well characterized by the buildup of amyloid-β plaques and tau protein tangles,leading to neurodegeneration and cognitive impairments.Recent prosperous Alzheimer's disease therapeutic d...Alzheimer's disease is well characterized by the buildup of amyloid-β plaques and tau protein tangles,leading to neurodegeneration and cognitive impairments.Recent prosperous Alzheimer's disease therapeutic development targeting amyloid-β validates the amyloid hypothesis.Nonetheless,the limited efficacy of single-target therapies plus as-observed synergy between amyloid-β and tau calls for a thorough understanding of Alzheimer's disease pathogenesis.Thus,this review introduces Alzheimer's disease pathogenesis,specifically focusing on the amyloid-β and tau pathologies,highlights their interconnected nature,presents personal perspectives on therapeutic and diagnostic challenges,and underscores the necessity of combined therapeutic approaches to effectively address Alzheimer's disease.展开更多
Alleviating the imbalance between urban and rural areas for regional coordinated development is an imperative response to the Sustainable Development Goal 10 of the United Nations.To track China’s urban-rural integra...Alleviating the imbalance between urban and rural areas for regional coordinated development is an imperative response to the Sustainable Development Goal 10 of the United Nations.To track China’s urban-rural integration progress and address the uneven issues in specific fields,this study constructed a novel seven-dimension index system of urban-rural integration,comprising free population mobility,efficient land transfer,interactive economic growth,highly-linked transportation,equal public services,joint environmental governance and unimpeded informatization between urban and rural areas.Based on a comprehensive measurement framework and multi-source panel data,we uncovered the spatial-temporal evolution of urban-rural integration in China’s 367 prefecture-level administrative units from 1980 to 2022.The results demonstrated that China’s urban-rural integration steadily increased from 27.51 to 57.35 with an average annual growth rate of 3.40%.Whereas,the overall urban-rural integration was relatively inferior in 2022,at the level of moderate integration whose proportion of China’s land area was 88.08%.The urban-rural integration level in eastern region and urban agglomerations was higher than that in mid-west and non-urban agglomerations.From the perspective of seven dimensions,interactive economic growth,joint environmental governance and unimpeded informatization made an obvious improvement and reached higher integration,while free population mobility,efficient land transfer,highly-linked transportation and equal public services maintained the stage of moderate integration in 2022.In the future,China should make targeted efforts for urban-rural integration in terms of population,land use,transportation and public services,and accelerate urban-rural common prosperity in the mid-west and economically underdeveloped areas.展开更多
Cooperative integrated sensing and communication(ISAC),an advanced version of ISAC,is becoming an inevitable paradigm in sixth-generation mobile information networks.Based on the foundation of largescale deployed mobi...Cooperative integrated sensing and communication(ISAC),an advanced version of ISAC,is becoming an inevitable paradigm in sixth-generation mobile information networks.Based on the foundation of largescale deployed mobile networks,cooperative ISAC holds promise to realize ubiquitous sensing,thus becoming a significant step in promoting the transformation from connected things to connected intelligence.In this paper,we depict a sweeping panorama of cooperative ISAC,including the concept,key technologies,a performance evaluation framework,and field trials.We start by introducing the application scenarios of cooperative ISAC,which are the motivation for its commercialization.Next,from the perspective of technical development,we trace the evolution of cooperative ISAC,noting that cooperation within sensing and communication is an objective trend.We reveal the four core features of cooperative ISAC-denoted herein as network-enabled,integration,cooperation,and everything-and provide a general system model.Regarding key technologies,we introduce our contributions to antenna array design,cooperative clustering,synchronization,and data fusion,as well as interference management and networking.We also propose an evaluation framework and define several key performance indicators for cooperative ISAC.Through system-level simulations and field trials,we show the practical application feasibility of cooperative ISAC.Finally,we provide guidance on future research directions in cooperative ISAC.展开更多
An aircraft carrier's formidable combat capability relies on sorties,with efficient deck operations as the core to enhance sortie and recovery capabilities.First,this study develops an integrated mathematical mode...An aircraft carrier's formidable combat capability relies on sorties,with efficient deck operations as the core to enhance sortie and recovery capabilities.First,this study develops an integrated mathematical model for carrier-based aircraft deployment,sortie,and maintenance scheduling to assist decision-makers in formulating sorties and coordinating resource allocation(e.g.,personnel,equipment),aiming to optimize the comprehensive effectiveness index of integrated carrier-based aircraft scheduling.Second,a hybrid multi-layer coded genetic algorithm(HMCGA)integrated with heuristic rules is proposed;it uses four-layer coding to resolve inter-sub-process coupling and supports integrated carrier-based aircraft scheduling,covering hangar transfer,deck transfer,aircraft maintenance support,and sortie execution.Then,case simulation shows the proposed model and algorithm effectively improve operational effectiveness and ensure accuracy.Finally,comparisons of 50 independent simulation results(PSO,DE,WOA,CPLEX)effectively validate HMCGA's superiority and universality in solving integrated carrier-based aircraft scheduling problems across fleet scales,further confirming the model and algorithm's reliability.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.12232009 and 12372002).
摘要Based on the discrete mechanics and optimal control framework,Hamel’s variational integrators are employed to solve the fuel-optimal and time-optimal control problems for a single rigid body.The optimal control problem is discretized via the discrete d’Alembert-Lagrange principle,and the corresponding discrete necessary conditions for optimality are derived.The sensitivity matrix is constructed and solved using the Newton-Armijo iteration method.This approach effectively linearizes the nonlinear problem,enhancing computational efficiency and ease of implementation.Finally,two numerical examples involving the optimal control of spacecraft orbital transfers are presented to verify the effectiveness and applicability of the proposed method.
基金supported by the National Natural Science Foundation of China (Grant Nos. 10872084 and 10932002)the Research Program of Higher Education of Liaoning Province,China (Grant No. 2008S098)+3 种基金the Program of Supporting Elitists of Higher Education of Liaoning Province,China (Grant No. 2008RC20)the Program of Constructing Liaoning Provincial Key Laboratory,China (Grant No. 2008403009)the Foundation Research Plan of Liaoning educational Bureau,China (Grant No. L2010147)the Youth fund of Liaoning University,China (Grant No. 2008LDQN04)
摘要The variational integrators of autonomous Birkhoff systems are obtained by the discrete variational principle. The geometric structure of the discrete autonomous Birkhoff system is formulated. The discretization of mathematical pendulum shows that the discrete variational method is as effective as symplectic scheme for the autonomous Birkhoff systems.
摘要Integrator based model is used to describe a wide range of systems in robotics. In this paper, we present an axis-coupled trajectory generation algorithm for chains of integrators with an arbitrary order. Special notice has been given to problems with pre-existing nominal plans, which are common in robotic applications. It also handles various type of constraints that can be satisfied on an entire time interval, including non-convex ones which can be transformed into a series of convex constraints through time segmentation. The proposed approach results in a linearly constrained quadratic programming problem, which can be solved effectively with off-the-shelf solvers. A closed-form solution is achievable with only the boundary constraints considered. Finally, the proposed method is tested in real experiments using quadrotors which represent high-order integrator systems.
基金supported by the National Natural Science Foundation of China(Grant No.11401259)the Fundamental Research Funds for the Central Universities,China(Grant No.JUSRR11407)
摘要In this paper, we propose a variational integrator for nonlinear Schrodinger equations with variable coefficients. It is shown that our variational integrator is naturally multi-symplectic. The discrete multi-symplectic structure of the integrator is presented by a multi-symplectic form formula that can be derived from the discrete Lagrangian boundary function. As two examples of nonlinear Schrodinger equations with variable coefficients, cubic nonlinear Schrodinger equations and Gross-Pitaevskii equations are extensively studied by the proposed integrator. Our numerical simulations demonstrate that the integrator is capable of preserving the mass, momentum, and energy conservation during time evolutions. Convergence tests are presented to verify that our integrator has second-order accuracy both in time and space.
摘要This paper studies a distributed optimal consensus problem for multiple double integrators under bounded velocity and acceleration. Assigned with an in dividual and private convex cost which is dependent on the position, each age nt n eeds to achieve consensus at the optimum of the aggregate cost under bounded velocity and acceleration. Based on relative positions and velocities to neighbor agents, we design a distributed control law by including the integration feedback of position and velocity errors. By employing quadratic Lyapunov functions, we solve the optimal consensus problem of double-integrators when the fixed topology is strongly connected and weight-balanced. Furthermore, if an initial estimate of the optimum can be known, then control gains can be properly selected to achieve an exponentially fast convergence under bounded velocity and acceleration. The result still holds when the relative velocity is not available, and we also discuss an extension for heterogeneous Euler-Lagrange systems by in verse dynamics control. A nu meric example is provided to illustrate the result.
基金Project supported by the National Natural Science Foundation of China (Grant Nos 10672143 and 60575055)the State Key Laboratory of Scientific and Engineering Computing, Chinese Academy of Sciencesthe Natural Science Foundation of Henan Province Government, China (Grant No 0511022200)
摘要A discrete total variation calculus with variable time steps is presented for mechanico-electrical systems where there exist non-potential and dissipative forces. By using this discrete variation calculus, the symplectic-energy-first integrators for mechanico-electrical systems are derived. To do this, the time step adaptation is employed. The discrete variational principle and the Euler-Lagrange equation are derived for the systems. By using this discrete algorithm it is shown that mechanico-electrical systems are not symplectic and their energies are not conserved unless they are Lagrange mechanico-electrical systems. A practical example is presented to illustrate these results.
基金by the National Natural Science Foundation of China under Grant No 10873007.
摘要Two new fourth-order three-stage symplectic integrators are specifically designed for a family of Hamiltonian systems,such as the harmonic oscillator,mathematical pendulum and latticeφ4 model.When the nonintegrable latticeφ4 system is taken as a test model,numerical comparisons show that the new methods have a great advantage over the second-order Verlet symplectic integrators in the accuracy of energy,become explicitly better than the usual non-gradient fourth-order seven-stage symplectic integrator of Forest and Ruth,and are almost equivalent to a fourth-order seven-stage force gradient symplectic integrator of Chin.As the most important advantage,the new integrators are convenient for solving the variational equations of many Hamiltonian systems so as to save a great deal of the computational cost when scanning a lot of orbits for chaos.
摘要N-body simulations of the Sun, the planets, and small celestial bodies are frequently used to model the evolution of the Solar System. Large numbers of numerical integrators for performing such simulations have been developed and used;see, for example, [1,2]. The primary objective of this paper is to analyse and compare the efficiency and the error growth for different numerical integrators. Throughout the paper, the error growth is examined in terms of the global errors in the positions and velocities, and the relative errors in the energy and angular momentum of the system. We performed numerical experiments for the different integrators applied to the Jovian problem over a long interval of duration, as long as one million years, with the local error tolerance ranging from 10-16 to 10-18.
基金Project supported by the National Natural Science Foundation of China (No.10572119)Program for New Century Excellent Talent of Ministry of Education of China (No.NCET-04-0958)the Open Foundation of State Key Laboratory of Structural Analysis of Industrial Equipmentthe Doctorate Foundation of Northwestern Polytechnical University
摘要Based on the Magnus integrator method established in linear dynamic systems, an efficiently improved modified Magnus integrator method was proposed for the second-order dynamic systems with time-dependent high frequencies. Firstly, the secondorder dynamic system was reformulated as the first-order system and the frame of reference was transfered by introducing new variables so that highly oscillatory behaviour inherits from the entries in the meantime. Then the modified Magnus integrator method based on local linearization was appropriately designed for solving the above new form and some improved also were presented. Finally, numerical examples show that the proposed methods appear to be quite adequate for integration for highly oscillatory dynamic systems including Hamiltonian systems problem with long time and effectiveness.
摘要For the problem of set point regulation of the liquid level in coupled tank systems, we present a continuous sliding mode control(SMC) with a "conditional integrator", which only provides integral action inside the boundary layer. For a special choice of the controller parameters, our design can be viewed as a PID controller with anti-windup and achieves robust regulation.The proposed controller recovers the transient response performance without control chattering. Both full-state feedback as well as output-feedback designs are presented in this work. Our output-feedback design uses a high-gain observer(HGO) which recovers the performance of a state-feedback design where plant parameters are assumed to be known. We consider both interacting as well as non-interacting tanks and analytical results for stability and transient performance are presented in both the cases. The proposed controller continuous SMC with conditional integrators(CSMCCI) provides superior results in terms of the performance measures as well as performance indices than ideal SMC, continuous SMC(CSMC) and continuous SMC with conventional integrator(CSMCI). Experimental results demonstrate good tracking performance in spite of unmodeled dynamics and disturbances.
摘要ZTE Corporation has signed strategic telecommunications software agreement with two leading providers in Europe and Latin America to optimize its offerings for target customers in
摘要In this work,a consistent and physically accurate implementation of the general framework of unified second-order time accurate integrators via the well-known GSSSS framework in the Discrete Element Method is presented.The improved tangential displacement evaluation in the present implementation of the discrete element method has been derived and implemented to preserve the consistency of the correct time level evaluation during the time integration process in calculating the algorithmic tangential displacement.Several numerical examples have been used to validate the proposed tangential displacement evaluation;this is in contrast to past practices which only seem to attain the first-order time accuracy due to inconsistent time level implementation with different algorithms for normal and tangential directions.The comparisons with the existing implementation and the superiority of the proposed implementation are given in terms of the convergence rate with improved numerical accuracy in time.Moreover,several schemes via the unified second-order time integrators within the framework of the GSSSS family have been carried out based on the proposed correct implementation.All the numerical results demonstrate that using the existing state-of-the-art implementation reduces the time accuracy to be first-order accurate in time,while the proposed implementation preserves the correct time accuracy to yield second-order.
基金Project supported by the National Natural Science Foundation of China(Nos.11172334 and11202247)the Fundamental Research Funds for the Central Universities(No.2013390003161292)
摘要This paper develops a new approach to construct variational integrators. A simplified unconventional Hamilton's variational principle corresponding to initial value problems is proposed, which is convenient for applications. The displacement and mo- mentum are approximated with the same Lagrange interpolation. After the numerical integration and variational operation, the original problems are expressed as algebraic equations with the displacement and momentum at the interpolation points as unknown variables. Some particular variational integrators are derived. An optimal scheme of choosing initial values for the Newton-Raphson method is presented for the nonlinear dynamic system. In addition, specific examples show that the proposed integrators are symplectic when the interpolation point coincides with the numerical integration point, and both are Gaussian quadrature points. Meanwhile, compared with the same order symplectic Runge-Kutta methods, although the accuracy of the two methods is almost the same, the proposed integrators are much simpler and less computationally expensive.
基金supported in part by the Research Grants Council of the Hong Kong Special Administration Region under Grant No.14201420in part by the National Natural Science Foundation of China under GrantNo.61973260.
摘要In this paper,the authors study the problem of distributed Nash equilibrium seeking of N-player games with high-order integrator dynamics subject to disturbances generated by an uncertain exosystem.Similar problems have been studied for disturbances with an exactly known exosystem.Compared with the existing results of high-order integrator dynamics,which can only handle sinusoidal disturbances with known frequencies,this paper aims to handle multi-tone disturbances with unknown frequencies by introducing an adaptive control technique to estimate the unknown frequencies.Technically,when the exosystem is known,the disturbance can be dealt with by the Luenburger observer.In contrast,the Luenburger observer cannot deal with an uncertain exosystem.The authors combine the internal model design and some adaptive control technique to solve the proposed problem.Further,the authors also establish the sufficient condition to guarantee the convergence of the estimated unknown frequencies to the actual values of these frequencies.Two examples are given to verify the proposed algorithm.
基金supported by the Financial Special Fund,grant number XZ202401JD0027National Barley Industry Technology System(CARS-05-01A-08)+3 种基金the Xizang Agri-Tech Innovation Project(XZNKY-2025-CXGC-T01)the Joint Funds of the National Natural Science Foundation of China(No.U20A2026)the Financial Special Fund,grant number(32401784,2017CZZX001/2,XZNKY-2018-C-021 and NYSTC202401)the China Agriculture Research System of Barley(CARS-05).
摘要Qingke,a staple crop grown on the high-altitude Tibetan Plateau,has evolved a metabolomic profile providing both environmental stress resilience and human nutrition.We review the hypothesis that the metabolites that confer cold and UV resistance on the crop also facilitate human adaptation to high-altitude stresses.Specifically,β-glucans regulate blood glucose primarily via short-chain fatty acids(SCFAs)produced through gut microbiota fermentation,which directly mediate glucose homeostasis.Phenolamides accumulate via the phenylpropanoid pathway,with chalcone isomerase(CHI)serving as a key enzyme in flavonoid biosynthesis and enhancing UV-B resistance.Under low temperatures,β-glucans improve frost tolerance by modulating osmotic balance and inhibiting ice-nucleating proteins,while lipids maintain membrane fluidity to sustain cellular function during cold stress.Importantly,we explore the hypothesis that these same metabolites,upon consumption,may facilitate human adaptation to high-altitude stresses.This hypothesis is supported by preliminary epidemiological associations between Qingke consumption and favorable health outcomes in high-altitude populations,as well as established bioactivities of the implicated metabolites in vitro and in animal models.However,direct causal evidence in humans and a comprehensive understanding of the underlying molecular mechanisms remain key knowledge gaps that warrant future investigation.Qingke as a unique resource at the interface of agricultural resilience and human nutrition.Understanding its metabolic blueprint will inform the development of functional foods and climate-resilient crops.
基金supported by the National Natural Science Foundation of China(91959106)the Foundation of the Shanghai Municipal Education Commission(24RGZNC02)+4 种基金Shanghai Key Laboratory of Intelligent Information Processing,Fudan University(IIPL-2025-RD3-02)Key University Science Research Project of Anhui Province(2023AH030108)Climbing Peak Training Program for Innovative Technology team of Yijishan Hospital,Wannan Medical College(PF201904)Peak Training Program for Scientific Research of Yijishan Hospital,Wannan Medical College(GF2019G15)the talent project of the First Affiliated Hospital of Wannan Medical College(Yijishan Hospital of Wannan Medical College)(YR202422).
摘要tRNA-derived small RNAs(tsRNAs),as a class of regulatory small noncoding RNA,have been implicated in a wide variety of human diseases.Large amounts of tsRNA–disease associations have been identified in recent years from accumulating studies.However,repositories for cataloging the detailed information on tsRNA–disease associations are scarce.In this study,we provide a tsRNADisease database by integrating experimentally and computationally supported tsRNA–disease associations from manual curation of literatures and other related resources.tsRNADisease contains 5571 manually curated associations between 4759 tsRNAs and 166 diseases with experimental evidence from 346 studies.In addition,it also contains 5013 predicted associations between 1297 tsRNAs and 111 diseases.tsRNADisease provides a user-friendly interface to browse,retrieve,and download data conveniently.This database can improve our understanding of tsRNA deregulation in diseases and serve as a valuable resource for investigating the mechanism of disease-related tsRNAs.tsRNADisease is freely available at http://gffzz9c504e06f78b4edahnoffqqoc9qvf6ucx.ffgz.tsg.suse.edu.cn.
基金the institutional support and access to academic resources that facilitates the preparation of this review,provided by the University of Miami,FL,USA。
摘要Alzheimer's disease is well characterized by the buildup of amyloid-β plaques and tau protein tangles,leading to neurodegeneration and cognitive impairments.Recent prosperous Alzheimer's disease therapeutic development targeting amyloid-β validates the amyloid hypothesis.Nonetheless,the limited efficacy of single-target therapies plus as-observed synergy between amyloid-β and tau calls for a thorough understanding of Alzheimer's disease pathogenesis.Thus,this review introduces Alzheimer's disease pathogenesis,specifically focusing on the amyloid-β and tau pathologies,highlights their interconnected nature,presents personal perspectives on therapeutic and diagnostic challenges,and underscores the necessity of combined therapeutic approaches to effectively address Alzheimer's disease.
基金supported by the Innovative Research Group Project of the National Natural Science Foundation of China(Grant No.42121001).
摘要Alleviating the imbalance between urban and rural areas for regional coordinated development is an imperative response to the Sustainable Development Goal 10 of the United Nations.To track China’s urban-rural integration progress and address the uneven issues in specific fields,this study constructed a novel seven-dimension index system of urban-rural integration,comprising free population mobility,efficient land transfer,interactive economic growth,highly-linked transportation,equal public services,joint environmental governance and unimpeded informatization between urban and rural areas.Based on a comprehensive measurement framework and multi-source panel data,we uncovered the spatial-temporal evolution of urban-rural integration in China’s 367 prefecture-level administrative units from 1980 to 2022.The results demonstrated that China’s urban-rural integration steadily increased from 27.51 to 57.35 with an average annual growth rate of 3.40%.Whereas,the overall urban-rural integration was relatively inferior in 2022,at the level of moderate integration whose proportion of China’s land area was 88.08%.The urban-rural integration level in eastern region and urban agglomerations was higher than that in mid-west and non-urban agglomerations.From the perspective of seven dimensions,interactive economic growth,joint environmental governance and unimpeded informatization made an obvious improvement and reached higher integration,while free population mobility,efficient land transfer,highly-linked transportation and equal public services maintained the stage of moderate integration in 2022.In the future,China should make targeted efforts for urban-rural integration in terms of population,land use,transportation and public services,and accelerate urban-rural common prosperity in the mid-west and economically underdeveloped areas.
基金funding from China Mobile Communications Group Co.,Ltd。
摘要Cooperative integrated sensing and communication(ISAC),an advanced version of ISAC,is becoming an inevitable paradigm in sixth-generation mobile information networks.Based on the foundation of largescale deployed mobile networks,cooperative ISAC holds promise to realize ubiquitous sensing,thus becoming a significant step in promoting the transformation from connected things to connected intelligence.In this paper,we depict a sweeping panorama of cooperative ISAC,including the concept,key technologies,a performance evaluation framework,and field trials.We start by introducing the application scenarios of cooperative ISAC,which are the motivation for its commercialization.Next,from the perspective of technical development,we trace the evolution of cooperative ISAC,noting that cooperation within sensing and communication is an objective trend.We reveal the four core features of cooperative ISAC-denoted herein as network-enabled,integration,cooperation,and everything-and provide a general system model.Regarding key technologies,we introduce our contributions to antenna array design,cooperative clustering,synchronization,and data fusion,as well as interference management and networking.We also propose an evaluation framework and define several key performance indicators for cooperative ISAC.Through system-level simulations and field trials,we show the practical application feasibility of cooperative ISAC.Finally,we provide guidance on future research directions in cooperative ISAC.
摘要An aircraft carrier's formidable combat capability relies on sorties,with efficient deck operations as the core to enhance sortie and recovery capabilities.First,this study develops an integrated mathematical model for carrier-based aircraft deployment,sortie,and maintenance scheduling to assist decision-makers in formulating sorties and coordinating resource allocation(e.g.,personnel,equipment),aiming to optimize the comprehensive effectiveness index of integrated carrier-based aircraft scheduling.Second,a hybrid multi-layer coded genetic algorithm(HMCGA)integrated with heuristic rules is proposed;it uses four-layer coding to resolve inter-sub-process coupling and supports integrated carrier-based aircraft scheduling,covering hangar transfer,deck transfer,aircraft maintenance support,and sortie execution.Then,case simulation shows the proposed model and algorithm effectively improve operational effectiveness and ensure accuracy.Finally,comparisons of 50 independent simulation results(PSO,DE,WOA,CPLEX)effectively validate HMCGA's superiority and universality in solving integrated carrier-based aircraft scheduling problems across fleet scales,further confirming the model and algorithm's reliability.