Deep reinforcement learning(DRL)has demonstrated exceptional capabilities in combinatorial optimization,which automatically devises policies for solution construction and optimizer refinement.DRL is particularly adept...Deep reinforcement learning(DRL)has demonstrated exceptional capabilities in combinatorial optimization,which automatically devises policies for solution construction and optimizer refinement.DRL is particularly adept in generating training samples by itself,thereby providing the flexibility to solve a variety of combinatorial optimization problems without supervision.While DRL takes actions according to states extracted from problem-specific information,it cannot be directly applied to black-box continuous optimization lacking explicit information.To address this issue,this paper proposes a search space independent operator based DRL method for black-box continuous optimization.It conceptualizes the optimization process driven by search space independent operators as a Markov decision process,wherein actions are defined as operators and states are extracted from solutions generated by operators.In contrast to other DRLassisted metaheuristics,the proposed method does not rely on any existing metaheuristic.Instead,it innovates by creating totally new operators,able to surpass the performance boundaries of existing metaheuristics.Compared with state-of-the-art metaheuristics and DRL methods,the proposed method shows significantly faster convergence speed on challenging continuous optimization problems.展开更多
For unknown nonlinear systems subject to asymmetric state and input constraints simultaneously,this article establishes a safe value iteration paradigm to learn an optimal control policy in a data-based manner.Initial...For unknown nonlinear systems subject to asymmetric state and input constraints simultaneously,this article establishes a safe value iteration paradigm to learn an optimal control policy in a data-based manner.Initially,the Koopman operator,instead of the black-box neural network,is applied to extract the inherent dynamics of the controlled systems from the measured data,thereby allowing for explicit analysis of the prediction error.To tackle the issue posed by state and input constraints,a crafted control barrier function is seamlessly incorporated into the canonical utility function,which retains the property of positive definiteness for the asymmetric case.Moreover,the value iteration algorithm with regard to the augmented utility function is adopted to attain a safe optimal controller,where the actor and critic networks are leveraged to approximate the control input and associated value function,respectively.The monotonicity,safety,and stability of the raised algorithm are further verified rigorously.Via performing three experiments on the linear system,the nonlinear system,and the manipulator plant,comparative results are obtained to substantiate the superiority and efficacy of the developed approach in achieving optimal performance and safe guarantee.展开更多
In this paper,we investigate the boundedness of pseudo-differential operators Tαon Besov spaces Bp,qswith symbol a∈Sρ,δm,0≤ρ≤δ<1.We obtain that Tαis bounded from Bp,qs+m-mc(p)to ...In this paper,we investigate the boundedness of pseudo-differential operators Tαon Besov spaces Bp,qswith symbol a∈Sρ,δm,0≤ρ≤δ<1.We obtain that Tαis bounded from Bp,qs+m-mc(p)to Bp,qs,where■.展开更多
In this paper,we obtain the dichotomy between mean equicontinuity and mean sensitivity for a sequence of bounded linear operators from a Banach space to a normed linear space.The mean Li-Yorke chaos for sequences and ...In this paper,we obtain the dichotomy between mean equicontinuity and mean sensitivity for a sequence of bounded linear operators from a Banach space to a normed linear space.The mean Li-Yorke chaos for sequences and submultiplicative sequences of bounded linear operators are also studied.Furthermore,several criteria for mean Li-Yorke chaos are established.展开更多
Bergman type operators are closely related to many basic problems on operator theory and function space theory.In this paper,we characterize the boundedness of logarithmic Bergman type operator Tλτc,k,k′from L^(...Bergman type operators are closely related to many basic problems on operator theory and function space theory.In this paper,we characterize the boundedness of logarithmic Bergman type operator Tλτc,k,k′from Lp(Bn,dvα)to Lq(Bn,dvβ)for some 1≤p,q≤+∞ and real α,β.These results generalize the relevant work of some scholars.At the same time,we partially solve the problem,put forward by Chen et al.in JMAA(2024).展开更多
It is well known that the inhomogeneous Calderón-Zygmund convolution operators are bounded on the local Hardy spaces.In this paper,we prove that these operators are bounded on the local product Hardy spaces and t...It is well known that the inhomogeneous Calderón-Zygmund convolution operators are bounded on the local Hardy spaces.In this paper,we prove that these operators are bounded on the local product Hardy spaces and the Lipschitz spaces.The key ideas used here are the discrete local Calderón identity and a density argument for the inhomogeneous product Lipschitz spaces in the weak sense.展开更多
Dual-polarization(dual-pol)radar variables provide information about the quantity,type,size,and water content of hydrometeors.Assimilating these dual-pol radar variables into numerical weather prediction models can en...Dual-polarization(dual-pol)radar variables provide information about the quantity,type,size,and water content of hydrometeors.Assimilating these dual-pol radar variables into numerical weather prediction models can enhance forecast accuracy.Observation operators are essential for radar data assimilation.This study focuses on applying a realistic dual-pol radar observation operator to more accurately calculate dual-pol radar variables.Previously reported dual-pol radar observation operators tended to overestimate radar variables near 0℃ in convective precipitation and simulate unrealistic dual-pol radar variables in subfreezing regions.To address this,the improved operator(KNU dual-pol radar observation operator;K-DROP)limits the distribution of mixed-phase hydrometeors,which have both solid and liquid properties,in areas with strong updrafts and downdrafts,improving the overestimation of radar variables near the melting layer.Additionally,by applying the observed snow axis ratio during winter to K-DROP,the issue of differential reflectivity(ZDR)being calculated as a constant value in subfreezing regions has been improved.By incorporating the observed maximum radius of hydrometeors into K-DROP,the overestimation of reflectivity(ZH)in subfreezing regions,the overestimation of ZDRin warm regions,and the underestimation of specific differential phase(KDP)in subfreezing regions and overestimation in warm regions,are improved.Compared to previous operators,the enhanced version reported in the present work produces more realistic dual-pol radar variables.展开更多
This paper investigates approximation problems in Orlicz spaces generated by Young functions.Utilizing Jensen’s inequality and the equivalence between the K-functional and the modulus of smoothness,we establish both ...This paper investigates approximation problems in Orlicz spaces generated by Young functions.Utilizing Jensen’s inequality and the equivalence between the K-functional and the modulus of smoothness,we establish both direct and inverse theorems for approximation by linear combinations of Szász-Mirakjan-Durrmeyer operators in these spaces.展开更多
Neural operators provide a data-driven framework for learning mappings between function spaces and have shown strong performance in scientific computing and surrogate modeling.Existing architectures,however,typically ...Neural operators provide a data-driven framework for learning mappings between function spaces and have shown strong performance in scientific computing and surrogate modeling.Existing architectures,however,typically rely on a single representation of the input function—either purely pointwise,as in DeepONet,or purely spectral,as in Fourier Neural Operators—which limits their ability to simultaneously capture local variability and global structure.In this work,we propose NOASLRR,a neural operator that integrates three complementary branches within a unified DeepONet-style formulation:a pointwise MLP embedding,a spectral branch based on Chebyshev polynomial coefficients,and a low-rank linear embedding.The three representations are fused through two learnable sigmoid gating mechanisms that adaptively balance structured inductive biases against unstructured expressivity in an input-dependent manner.We provide a theoretical guarantee showing that the proposed architecture can uniformly approximate any continuous operator admitting a decomposable structure,and we validate the method on three canonical PDE benchmarks:the heat equation,the viscous Burgers equation,and the Laplace equation with Dirichlet boundary conditions.On all three benchmarks NOASLRR converges faster and reaches substantially lower mean squared error than DeepONet and FNO baselines—for the heat equation the final MSE is reduced from 1.1×10⁻³(DeepONet)and 2.9×10⁻²(FNO)to 3.4×10⁻⁴,with comparable improvements on the Burgers and Laplace equations.Ablation experiments further confirm that each of the three branches contributes to the accuracy gains,while the parameter overhead relative to DeepONet remains moderate thanks to the low-rank factorization.展开更多
Long-term prediction of three-dimensional(3D)turbulent flows is one of the most challenging problems for machine learning approaches.Although some existing machine learning approaches,such as implicit U-net enhanced F...Long-term prediction of three-dimensional(3D)turbulent flows is one of the most challenging problems for machine learning approaches.Although some existing machine learning approaches,such as implicit U-net enhanced Fourier neural operator(IUFNO),have been proven to be capable of achieving stable long-term predictions for turbulent flows,their computational costs are usually high.In this paper,we use the adaptive Fourier neural operator(AFNO)as the backbone to construct a model that can predict 3D turbulence.Furthermore,we employ the implicit iteration to our constructed AFNO and propose the implicit adaptive Fourier neural operator(IAFNO).IAFNO is systematically tested in three types of 3D turbulence,including forced homogeneous isotropic turbulence(HIT),temporally evolving turbulent mixing layer,and turbulent channel flow.The numerical results demonstrate that IAFNO is more accurate than IUFNO and the traditional large-eddy simulation using the dynamic Smagorinsky model(DSM),while exhibiting greater stability compared to IUFNO.Meanwhile,the AFNO model exhibits instability in numerical simulations.Moreover,the training efficiency of IAFNO is 4 times higher than that of IUFNO,and the number of parameters and GPU memory occupation of IAFNO are only 1/80 and 1/3 of IUFNO,respectively in HIT.In other tests,the improvements are slightly lower but still considerable.These improvements mainly come from patching and self-attention in 3D space.Besides,the well-trained IAFNO is significantly faster than the DSM.Code and data available at:http://gffzz188fe103f8f1460aswububn6xf65v6pqx.ffgz.tsg.suse.edu.cn/yuchi-richard-jiang/IAFNO.展开更多
The behavior of materials is influenced by a wide range of phenomena occurring across various time and length scales.To better understand the impact of microstructure on the macroscopic response,multiscale modeling st...The behavior of materials is influenced by a wide range of phenomena occurring across various time and length scales.To better understand the impact of microstructure on the macroscopic response,multiscale modeling strategies are essential.Numerical methods,such as the FE2-approach,account for micro-macro interactions to predict the global response in a concurrent manner.However,these methods are computationally intensive because of the repeated evaluations of the discretized microscale.This challenge has led to the integration of deep learning techniques into computational homogenization frameworks to accelerate multiscale simulations.In this work,we employ neural operators to predict microscale physics,resulting in a hybrid model that combines datadriven and physics-based approaches.This allows for physics-guided learning and provides flexibility for different materials and spatial discretizations.We apply this method to time-dependent solid mechanics problems involving viscoelastic material behavior,where the state is represented by internal variables only at the microscale.The constitutive relationships at the microscale are incorporated into the model architecture and the internal variables are computed on the basis of established physical principles.The results for homogenized stresses(<6%error)show that the approach is computationally efficient(~100×faster).展开更多
In this paper,we study truncated Toeplitz operators and little truncated Hankel operators on Np,q-type quotient modules over the bidisk.We find a necessary and sufficient condition for a truncated Toeplitz operator to...In this paper,we study truncated Toeplitz operators and little truncated Hankel operators on Np,q-type quotient modules over the bidisk.We find a necessary and sufficient condition for a truncated Toeplitz operator to be zero,as a result,we find a characterization equation for bounded truncated Toeplitz operators.We also find a necessary and sufficient condition for a little truncated Hankel operator to be zero operator.This paper also studies the spectra,joint spectra and the essential spectra of truncated Toeplitz operators with some special symbols.展开更多
Aircraft assembly is characterized by stringent precedence constraints,limited resource availability,spatial restrictions,and a high degree of manual intervention.These factors lead to considerable variability in oper...Aircraft assembly is characterized by stringent precedence constraints,limited resource availability,spatial restrictions,and a high degree of manual intervention.These factors lead to considerable variability in operator workloads and significantly increase the complexity of scheduling.To address this challenge,this study investigates the Aircraft Pulsating Assembly Line Scheduling Problem(APALSP)under skilled operator allocation,with the objective of minimizing assembly completion time.A mathematical model considering skilled operator allocation is developed,and a Q-Learning improved Particle Swarm Optimization algorithm(QLPSO)is proposed.In the algorithm design,a reverse scheduling strategy is adopted to effectively manage large-scale precedence constraints.Moreover,a reverse sequence encoding method is introduced to generate operation sequences,while a time decoding mechanism is employed to determine completion times.The problem is further reformulated as a Markov Decision Process(MDP)with explicitly defined state and action spaces.Within QLPSO,the Q-learning mechanism adaptively adjusts inertia weights and learning factors,thereby achieving a balance between exploration capability and convergence performance.To validate the effectiveness of the proposed approach,extensive computational experiments are conducted on benchmark instances of different scales,including small,medium,large,and ultra-large cases.The results demonstrate that QLPSO consistently delivers stable and high-quality solutions across all scenarios.In ultra-large-scale instances,it improves the best solution by 25.2%compared with the Genetic Algorithm(GA)and enhances the average solution by 16.9%over the Q-learning algorithm,showing clear advantages over the comparative methods.These findings not only confirm the effectiveness of the proposed algorithm but also provide valuable theoretical references and practical guidance for the intelligent scheduling optimization of aircraft pulsating assembly lines.展开更多
In this article we consider a modification of the Stein’s spherical maximal operator of complex order a on Rn:■We show that when n≥,suppose||mα[1,2]f||Lq(Rn)≤C||f||Lp(Rn)holds for someα∈C,...In this article we consider a modification of the Stein’s spherical maximal operator of complex order a on Rn:■We show that when n≥,suppose||mα[1,2]f||Lq(Rn)≤C||f||Lp(Rn)holds for someα∈C,p,q≥,then we must have that q≥p and Reα≥σn(p,q):=max{1/p-n/q,n+1/2p-n-1/2(1/q+1),n/p-n+1}.Conversely,we show that Mα[1,2]is bounded from Lp(Rn)to Lq(Rn)provided that q≥p and Reα>σ2(p,q)for n=2;and Reα>max{σn(p,q),1/(2p)-(n-2)/(2q)-(n-1)/4}for n>2.The range ofα,p and q is almost optimal in the case when either n=2,or a=0,or(p,q)lies in certain regions for n>2.展开更多
This paper presents a data-driven economic model predictive control(EMPC)framework for nonlinear systems.Leveraging Koopman operator theory and the extended dynamic mode decomposition method,a lifted linear model in t...This paper presents a data-driven economic model predictive control(EMPC)framework for nonlinear systems.Leveraging Koopman operator theory and the extended dynamic mode decomposition method,a lifted linear model in the high-dimensional function space of the nonlinear dynamics is first identified from the collected dataset.Then,an EMPC strategy used to optimize process economics is designed in the lifted space,which employs the Koopman linear model as the predictor.To guarantee closed-loop stability,an artificial constraint is constructed by solving a convex quadratic programming problem.The recursive feasibility and closed-loop stability of the proposed approach are rigorously analyzed.Benefiting from the linear structure of the Koopman model,the online computational burden of the EMPC is substantially reduced.The effectiveness of the proposed method is demonstrated through simulations on a nonlinear chemical reactor.展开更多
Letα>0 and letμbe a positive Borel measure on the interval[0,1).The Hankel matrix■with entries■induces,formally,the generalized-Hilbert operator■where f(z)■is an analytic function in D.This article is devoted...Letα>0 and letμbe a positive Borel measure on the interval[0,1).The Hankel matrix■with entries■induces,formally,the generalized-Hilbert operator■where f(z)■is an analytic function in D.This article is devoted to study the measuresμfor which Hμ,αis a bounded(resp.,compact)operator from Hp(0<p≤1)into Hp(1≤q<∞).We also study the analogous problem in the Hardy spaces Hp(1≤p≤2).Finally,we obtain the essential norm of Hμ,αfrom Hp(0<p≤1)into Hp(1≤q<∞).展开更多
The goal of this paper is to establish the boundedness of the p-adic fractional integral operator with rough kernel Iβ,Ω′pand its commutators generated by b∈Λγ(Qpn)(0<γ<1)and the I_(β,Ω′...The goal of this paper is to establish the boundedness of the p-adic fractional integral operator with rough kernel Iβ,Ω′pand its commutators generated by b∈Λγ(Qpn)(0<γ<1)and the Iβ,Ω′p on grand p-adic Herz spaces.展开更多
In this paper,we prove the boundedness of strongly singular Calderón-Zygmund operators and their corresponding commutators when mapping from Musielak-Orlicz Hardy spaces into Musielak-Orlicz spaces.By introducing...In this paper,we prove the boundedness of strongly singular Calderón-Zygmund operators and their corresponding commutators when mapping from Musielak-Orlicz Hardy spaces into Musielak-Orlicz spaces.By introducing a specific subspace of BMO,we further show that the commutators generated by functions within this subspace and strongly singular Calderón-Zygmund operators remain bounded under the same mapping framework.展开更多
In this article,we prove the boundedness for commutators of fractional Hardy and Hardy-Littlewood-Pólya operators on grand p-adic variable Herz spaces,where the symbols of the commutators belong to Lipschitz spaces.
Metasurface design often requires solving field distributions across varying structural parameters and frequencies,where neural operators offer a promising avenue for fast prediction.However,conventional neural operat...Metasurface design often requires solving field distributions across varying structural parameters and frequencies,where neural operators offer a promising avenue for fast prediction.However,conventional neural operators have problems with degradation of the accuracy in multi-scale structural analysis.In this work,we propose a Generative Residual Enhanced Neural Operator(GRE-NO)framework that introduces a generative residual network to model the systematic bias of the main predictor.The core model retains the DeepONet architecture with both branch and trunk networks implemented using Fourier Neural Operators,combining strong generalization and efficient global representation.To handle the complexity of unbounded acoustic scattering problems,we integrate the Boundary Element Method(BEM)into data modeling and field computation,which reduces the problem dimensionality and enables training with samples at the 104 scale.Numerical experiments on some 2D and 3D acoustic metasurface problems demonstrate that the developed GRE-NO achieves excellent accuracy in results with relative errors under 1%in this study,outperforming conventional neural networks in accuracy of prediction.展开更多
基金supported in part by the National Natural Science Foundation of China(62136008,62276001,U21A20512,W2441019)the Anhui Provincial Natural Science Foundation(2308085J03)the Excellent Youth Foundation of Anhui Provincial Colleges(2022AH030013)。
摘要Deep reinforcement learning(DRL)has demonstrated exceptional capabilities in combinatorial optimization,which automatically devises policies for solution construction and optimizer refinement.DRL is particularly adept in generating training samples by itself,thereby providing the flexibility to solve a variety of combinatorial optimization problems without supervision.While DRL takes actions according to states extracted from problem-specific information,it cannot be directly applied to black-box continuous optimization lacking explicit information.To address this issue,this paper proposes a search space independent operator based DRL method for black-box continuous optimization.It conceptualizes the optimization process driven by search space independent operators as a Markov decision process,wherein actions are defined as operators and states are extracted from solutions generated by operators.In contrast to other DRLassisted metaheuristics,the proposed method does not rely on any existing metaheuristic.Instead,it innovates by creating totally new operators,able to surpass the performance boundaries of existing metaheuristics.Compared with state-of-the-art metaheuristics and DRL methods,the proposed method shows significantly faster convergence speed on challenging continuous optimization problems.
摘要For unknown nonlinear systems subject to asymmetric state and input constraints simultaneously,this article establishes a safe value iteration paradigm to learn an optimal control policy in a data-based manner.Initially,the Koopman operator,instead of the black-box neural network,is applied to extract the inherent dynamics of the controlled systems from the measured data,thereby allowing for explicit analysis of the prediction error.To tackle the issue posed by state and input constraints,a crafted control barrier function is seamlessly incorporated into the canonical utility function,which retains the property of positive definiteness for the asymmetric case.Moreover,the value iteration algorithm with regard to the augmented utility function is adopted to attain a safe optimal controller,where the actor and critic networks are leveraged to approximate the control input and associated value function,respectively.The monotonicity,safety,and stability of the raised algorithm are further verified rigorously.Via performing three experiments on the linear system,the nonlinear system,and the manipulator plant,comparative results are obtained to substantiate the superiority and efficacy of the developed approach in achieving optimal performance and safe guarantee.
基金Supported by NSFC(No.12071437)NSF from the Education Department of Anhui Province(No.2024AH051332)。
摘要In this paper,we investigate the boundedness of pseudo-differential operators Tαon Besov spaces Bp,qswith symbol a∈Sρ,δm,0≤ρ≤δ<1.We obtain that Tαis bounded from Bp,qs+m-mc(p)to Bp,qs,where■.
基金suported in part by the NSF of China(12222110)supported in part by the NSF of China(12301230)+1 种基金the STU Scientific Research Initiation Grant(SRIG,NTF22020)supported by the NSF of China(12301226).
摘要In this paper,we obtain the dichotomy between mean equicontinuity and mean sensitivity for a sequence of bounded linear operators from a Banach space to a normed linear space.The mean Li-Yorke chaos for sequences and submultiplicative sequences of bounded linear operators are also studied.Furthermore,several criteria for mean Li-Yorke chaos are established.
基金supported by the Education Department Important Foundation of Hunan Province in China(23A0095).
摘要Bergman type operators are closely related to many basic problems on operator theory and function space theory.In this paper,we characterize the boundedness of logarithmic Bergman type operator Tλτc,k,k′from Lp(Bn,dvα)to Lq(Bn,dvβ)for some 1≤p,q≤+∞ and real α,β.These results generalize the relevant work of some scholars.At the same time,we partially solve the problem,put forward by Chen et al.in JMAA(2024).
基金supported by the NSFC(12301115)the Natural Science Foundation of Huzhou(2023YZ11,2024YZ37)the second author was supported by the NSFC(12071437).
摘要It is well known that the inhomogeneous Calderón-Zygmund convolution operators are bounded on the local Hardy spaces.In this paper,we prove that these operators are bounded on the local product Hardy spaces and the Lipschitz spaces.The key ideas used here are the discrete local Calderón identity and a density argument for the inhomogeneous product Lipschitz spaces in the weak sense.
基金supported by the National Research Foundation(NRF)funded by the Korean government(MSIT)(Grant Nos.2022R1A2C1012361,2022R1A6A3A 13073165 and RS-2025-02242970).
摘要Dual-polarization(dual-pol)radar variables provide information about the quantity,type,size,and water content of hydrometeors.Assimilating these dual-pol radar variables into numerical weather prediction models can enhance forecast accuracy.Observation operators are essential for radar data assimilation.This study focuses on applying a realistic dual-pol radar observation operator to more accurately calculate dual-pol radar variables.Previously reported dual-pol radar observation operators tended to overestimate radar variables near 0℃ in convective precipitation and simulate unrealistic dual-pol radar variables in subfreezing regions.To address this,the improved operator(KNU dual-pol radar observation operator;K-DROP)limits the distribution of mixed-phase hydrometeors,which have both solid and liquid properties,in areas with strong updrafts and downdrafts,improving the overestimation of radar variables near the melting layer.Additionally,by applying the observed snow axis ratio during winter to K-DROP,the issue of differential reflectivity(ZDR)being calculated as a constant value in subfreezing regions has been improved.By incorporating the observed maximum radius of hydrometeors into K-DROP,the overestimation of reflectivity(ZH)in subfreezing regions,the overestimation of ZDRin warm regions,and the underestimation of specific differential phase(KDP)in subfreezing regions and overestimation in warm regions,are improved.Compared to previous operators,the enhanced version reported in the present work produces more realistic dual-pol radar variables.
基金supported by the Natural Science Foundation of Inner Mongolia Autonomous Region (No. 2025LHMS01014)。
摘要This paper investigates approximation problems in Orlicz spaces generated by Young functions.Utilizing Jensen’s inequality and the equivalence between the K-functional and the modulus of smoothness,we establish both direct and inverse theorems for approximation by linear combinations of Szász-Mirakjan-Durrmeyer operators in these spaces.
基金supported by grant No.25-71-10012 from the Russian Science Foundation,http://gffzz5363282ec1d94f2dswububn6xf65v6pqx.ffgz.tsg.suse.edu.cn/project/25-71-10012/.
摘要Neural operators provide a data-driven framework for learning mappings between function spaces and have shown strong performance in scientific computing and surrogate modeling.Existing architectures,however,typically rely on a single representation of the input function—either purely pointwise,as in DeepONet,or purely spectral,as in Fourier Neural Operators—which limits their ability to simultaneously capture local variability and global structure.In this work,we propose NOASLRR,a neural operator that integrates three complementary branches within a unified DeepONet-style formulation:a pointwise MLP embedding,a spectral branch based on Chebyshev polynomial coefficients,and a low-rank linear embedding.The three representations are fused through two learnable sigmoid gating mechanisms that adaptively balance structured inductive biases against unstructured expressivity in an input-dependent manner.We provide a theoretical guarantee showing that the proposed architecture can uniformly approximate any continuous operator admitting a decomposable structure,and we validate the method on three canonical PDE benchmarks:the heat equation,the viscous Burgers equation,and the Laplace equation with Dirichlet boundary conditions.On all three benchmarks NOASLRR converges faster and reaches substantially lower mean squared error than DeepONet and FNO baselines—for the heat equation the final MSE is reduced from 1.1×10⁻³(DeepONet)and 2.9×10⁻²(FNO)to 3.4×10⁻⁴,with comparable improvements on the Burgers and Laplace equations.Ablation experiments further confirm that each of the three branches contributes to the accuracy gains,while the parameter overhead relative to DeepONet remains moderate thanks to the low-rank factorization.
基金supported by the National Natural Science Foundation of China(NSFC)(Grant Nos.12172161,12302283,92052301,and 12161141017)the NSFC Basic Science Center Program(Grant No.11988102)+2 种基金the Shenzhen Science and Technology Program(Grant No.KQTD20180411143441009)the Department of Science and Technology of Guangdong Province(Grant Nos.2019B21203001,2020B1212030001,and 2023B1212060001)the Innovation Capability Support Program of Shaanxi(Grant No.2023-CX-TD-30).
摘要Long-term prediction of three-dimensional(3D)turbulent flows is one of the most challenging problems for machine learning approaches.Although some existing machine learning approaches,such as implicit U-net enhanced Fourier neural operator(IUFNO),have been proven to be capable of achieving stable long-term predictions for turbulent flows,their computational costs are usually high.In this paper,we use the adaptive Fourier neural operator(AFNO)as the backbone to construct a model that can predict 3D turbulence.Furthermore,we employ the implicit iteration to our constructed AFNO and propose the implicit adaptive Fourier neural operator(IAFNO).IAFNO is systematically tested in three types of 3D turbulence,including forced homogeneous isotropic turbulence(HIT),temporally evolving turbulent mixing layer,and turbulent channel flow.The numerical results demonstrate that IAFNO is more accurate than IUFNO and the traditional large-eddy simulation using the dynamic Smagorinsky model(DSM),while exhibiting greater stability compared to IUFNO.Meanwhile,the AFNO model exhibits instability in numerical simulations.Moreover,the training efficiency of IAFNO is 4 times higher than that of IUFNO,and the number of parameters and GPU memory occupation of IAFNO are only 1/80 and 1/3 of IUFNO,respectively in HIT.In other tests,the improvements are slightly lower but still considerable.These improvements mainly come from patching and self-attention in 3D space.Besides,the well-trained IAFNO is significantly faster than the DSM.Code and data available at:http://gffzz188fe103f8f1460aswububn6xf65v6pqx.ffgz.tsg.suse.edu.cn/yuchi-richard-jiang/IAFNO.
基金supported by the German Federal Ministry of Education and Research(BMBF)for the project“MOdellkopplung im Kontext eines VIrtuellen Untertagelabors und dessen Entwicklungsprozess–MOVIE”,within the research program“GEO:N–Geosciences for Sustainability”under the topic“Digital Geosystems:Virtual Methods and Digital Tools for Geoscientific Applications”(Grant No.03G0921A/2024-01 to 2026-12)the Ministry of Science and Culture of Lower Saxony and the Volkswagen Foundation for the Research Training Group Circular LIB through the zukunft.niedersachsen program(Grant No.MWK|ZN3678)。
摘要The behavior of materials is influenced by a wide range of phenomena occurring across various time and length scales.To better understand the impact of microstructure on the macroscopic response,multiscale modeling strategies are essential.Numerical methods,such as the FE2-approach,account for micro-macro interactions to predict the global response in a concurrent manner.However,these methods are computationally intensive because of the repeated evaluations of the discretized microscale.This challenge has led to the integration of deep learning techniques into computational homogenization frameworks to accelerate multiscale simulations.In this work,we employ neural operators to predict microscale physics,resulting in a hybrid model that combines datadriven and physics-based approaches.This allows for physics-guided learning and provides flexibility for different materials and spatial discretizations.We apply this method to time-dependent solid mechanics problems involving viscoelastic material behavior,where the state is represented by internal variables only at the microscale.The constitutive relationships at the microscale are incorporated into the model architecture and the internal variables are computed on the basis of established physical principles.The results for homogenized stresses(<6%error)show that the approach is computationally efficient(~100×faster).
基金supported by the Scientific Research Fund of Hunan Provincial Education Departmentsupported by the National Natural Science Foundation of China(12571132)。
摘要In this paper,we study truncated Toeplitz operators and little truncated Hankel operators on Np,q-type quotient modules over the bidisk.We find a necessary and sufficient condition for a truncated Toeplitz operator to be zero,as a result,we find a characterization equation for bounded truncated Toeplitz operators.We also find a necessary and sufficient condition for a little truncated Hankel operator to be zero operator.This paper also studies the spectra,joint spectra and the essential spectra of truncated Toeplitz operators with some special symbols.
基金supported by the National Natural Science Foundation of China(Grant No.52475543)Natural Science Foundation of Henan(Grant No.252300421101)+1 种基金Henan Province University Science and Technology Innovation Talent Support Plan(Grant No.24HASTIT048)Science and Technology Innovation Team Project of Zhengzhou University of Light Industry(Grant No.23XNKJTD0101).
摘要Aircraft assembly is characterized by stringent precedence constraints,limited resource availability,spatial restrictions,and a high degree of manual intervention.These factors lead to considerable variability in operator workloads and significantly increase the complexity of scheduling.To address this challenge,this study investigates the Aircraft Pulsating Assembly Line Scheduling Problem(APALSP)under skilled operator allocation,with the objective of minimizing assembly completion time.A mathematical model considering skilled operator allocation is developed,and a Q-Learning improved Particle Swarm Optimization algorithm(QLPSO)is proposed.In the algorithm design,a reverse scheduling strategy is adopted to effectively manage large-scale precedence constraints.Moreover,a reverse sequence encoding method is introduced to generate operation sequences,while a time decoding mechanism is employed to determine completion times.The problem is further reformulated as a Markov Decision Process(MDP)with explicitly defined state and action spaces.Within QLPSO,the Q-learning mechanism adaptively adjusts inertia weights and learning factors,thereby achieving a balance between exploration capability and convergence performance.To validate the effectiveness of the proposed approach,extensive computational experiments are conducted on benchmark instances of different scales,including small,medium,large,and ultra-large cases.The results demonstrate that QLPSO consistently delivers stable and high-quality solutions across all scenarios.In ultra-large-scale instances,it improves the best solution by 25.2%compared with the Genetic Algorithm(GA)and enhances the average solution by 16.9%over the Q-learning algorithm,showing clear advantages over the comparative methods.These findings not only confirm the effectiveness of the proposed algorithm but also provide valuable theoretical references and practical guidance for the intelligent scheduling optimization of aircraft pulsating assembly lines.
基金supported by National Key R&D Program of China 2022YFA1005700N.J.Liu is supported by China Postdoctoral Science Foundation(No.2024M763732)+4 种基金NNSF of China(No.12501132)M.X.Shen is supported by China Postdoctoral Science Foundation(No.2024M761509)NNSF of China(No.12501125)L.Song is supported by NNSF of China(No.12471097)L.X.Yan is supported by NNSF of China(No.12571111).
摘要In this article we consider a modification of the Stein’s spherical maximal operator of complex order a on Rn:■We show that when n≥,suppose||mα[1,2]f||Lq(Rn)≤C||f||Lp(Rn)holds for someα∈C,p,q≥,then we must have that q≥p and Reα≥σn(p,q):=max{1/p-n/q,n+1/2p-n-1/2(1/q+1),n/p-n+1}.Conversely,we show that Mα[1,2]is bounded from Lp(Rn)to Lq(Rn)provided that q≥p and Reα>σ2(p,q)for n=2;and Reα>max{σn(p,q),1/(2p)-(n-2)/(2q)-(n-1)/4}for n>2.The range ofα,p and q is almost optimal in the case when either n=2,or a=0,or(p,q)lies in certain regions for n>2.
基金supported by the National Natural Science Foundation of China(No.61833007)the 2025 Fundamental Research Funds for the Central Universities(Youth Program 1332050205256400).
摘要This paper presents a data-driven economic model predictive control(EMPC)framework for nonlinear systems.Leveraging Koopman operator theory and the extended dynamic mode decomposition method,a lifted linear model in the high-dimensional function space of the nonlinear dynamics is first identified from the collected dataset.Then,an EMPC strategy used to optimize process economics is designed in the lifted space,which employs the Koopman linear model as the predictor.To guarantee closed-loop stability,an artificial constraint is constructed by solving a convex quadratic programming problem.The recursive feasibility and closed-loop stability of the proposed approach are rigorously analyzed.Benefiting from the linear structure of the Koopman model,the online computational burden of the EMPC is substantially reduced.The effectiveness of the proposed method is demonstrated through simulations on a nonlinear chemical reactor.
基金supported by the Zhejiang Province Natural Science Foundation of China(LY23A010003).
摘要Letα>0 and letμbe a positive Borel measure on the interval[0,1).The Hankel matrix■with entries■induces,formally,the generalized-Hilbert operator■where f(z)■is an analytic function in D.This article is devoted to study the measuresμfor which Hμ,αis a bounded(resp.,compact)operator from Hp(0<p≤1)into Hp(1≤q<∞).We also study the analogous problem in the Hardy spaces Hp(1≤p≤2).Finally,we obtain the essential norm of Hμ,αfrom Hp(0<p≤1)into Hp(1≤q<∞).
基金Supported by Natural Science Foundation of China(12461021)。
摘要The goal of this paper is to establish the boundedness of the p-adic fractional integral operator with rough kernel Iβ,Ω′pand its commutators generated by b∈Λγ(Qpn)(0<γ<1)and the Iβ,Ω′p on grand p-adic Herz spaces.
基金partially supported by the National Natural Science Foundation of China(12171250,U21A20426,12271267)。
摘要In this paper,we prove the boundedness of strongly singular Calderón-Zygmund operators and their corresponding commutators when mapping from Musielak-Orlicz Hardy spaces into Musielak-Orlicz spaces.By introducing a specific subspace of BMO,we further show that the commutators generated by functions within this subspace and strongly singular Calderón-Zygmund operators remain bounded under the same mapping framework.
基金Supported by Chizhou University High Level Talent Research Start up Fund (No.CZ2025YJRC52)。
摘要In this article,we prove the boundedness for commutators of fractional Hardy and Hardy-Littlewood-Pólya operators on grand p-adic variable Herz spaces,where the symbols of the commutators belong to Lipschitz spaces.
基金funded by National Natural Science Foundation of China(Grant number 12372198).
摘要Metasurface design often requires solving field distributions across varying structural parameters and frequencies,where neural operators offer a promising avenue for fast prediction.However,conventional neural operators have problems with degradation of the accuracy in multi-scale structural analysis.In this work,we propose a Generative Residual Enhanced Neural Operator(GRE-NO)framework that introduces a generative residual network to model the systematic bias of the main predictor.The core model retains the DeepONet architecture with both branch and trunk networks implemented using Fourier Neural Operators,combining strong generalization and efficient global representation.To handle the complexity of unbounded acoustic scattering problems,we integrate the Boundary Element Method(BEM)into data modeling and field computation,which reduces the problem dimensionality and enables training with samples at the 104 scale.Numerical experiments on some 2D and 3D acoustic metasurface problems demonstrate that the developed GRE-NO achieves excellent accuracy in results with relative errors under 1%in this study,outperforming conventional neural networks in accuracy of prediction.