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The Asymptotic Distribution of General Divisor Problem Associated to Dedekind Zeta Function over Certain Sequences
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作者 HUA Guodong 《数学进展》 北大核心 2026年第2期292-314,共23页
Let K_(j)/Q,1≤j≤ν,ν≥2 be quadratic fields with pairwise coprime discriminants Dj,and let τ_(kj)^(K_(j))(n)be the divisor function associated to Dedekind zeta function SK_(j)(s).In this paper,we consider a multid... Let K_(j)/Q,1≤j≤ν,ν≥2 be quadratic fields with pairwise coprime discriminants Dj,and let τ_(kj)^(K_(j))(n)be the divisor function associated to Dedekind zeta function SK_(j)(s).In this paper,we consider a multidimensional general divisor problem related to the τ_(kj)^(K_(j))(n)involving several number fields over square integers,by establishing the corresponding asymptotic formula.As an application,we also obtain the asymptotic formula of variance of these coefi icients. 展开更多
关键词 non-normal cubic field Dekekind zeta function divisor problem
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Nonlocal Boundary Value Problems for Nonlinear Fractional Differential Equations with a Disturbance Parameter on the Infinite Interval
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作者 ZHENG Yanping YANG Hui WANG Wenxia 《应用数学》 北大核心 2026年第2期360-372,共13页
This paper is concerned with a class of nonlinear fractional differential equations with a disturbance parameter in the integral boundary conditions on the infinite interval.By using Guo-Krasnoselskii fixed point theo... This paper is concerned with a class of nonlinear fractional differential equations with a disturbance parameter in the integral boundary conditions on the infinite interval.By using Guo-Krasnoselskii fixed point theorem,fixed point index theory and the analytic technique,we give the bifurcation point of the parameter which divides the range of parameter for the existence of at least two,one and no positive solutions for the problem.And,by using a fixed point theorem of generalized concave operator and cone theory,we establish the maximum parameter interval for the existence of the unique positive solution for the problem and show that such a positive solution continuously depends on the parameter.In the end,some examples are given to illustrate our main results. 展开更多
关键词 Boundary value problem Disturbance parameter Infinite interval Bifurcation point CONE
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Graph Guide Diffusion Solvers with Noises for Travelling Salesman Problem
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作者 Yan Kong Xinpeng Guo Chih-Hsien Hsia 《Computers, Materials & Continua》 2026年第3期689-707,共19页
With the development of technology,diffusion model-based solvers have shown significant promise in solving Combinatorial Optimization(CO)problems,particularly in tackling Non-deterministic Polynomial-time hard(NP-hard... With the development of technology,diffusion model-based solvers have shown significant promise in solving Combinatorial Optimization(CO)problems,particularly in tackling Non-deterministic Polynomial-time hard(NP-hard)problems such as the Traveling Salesman Problem(TSP).However,existing diffusion model-based solvers typically employ a fixed,uniform noise schedule(e.g.,linear or cosine annealing)across all training instances,failing to fully account for the unique characteristics of each problem instance.To address this challenge,we present GraphGuided Diffusion Solvers(GGDS),an enhanced method for improving graph-based diffusion models.GGDS leverages Graph Neural Networks(GNNs)to capture graph structural information embedded in node coordinates and adjacency matrices,dynamically adjusting the noise levels in the diffusion model.This study investigates the TSP by examining two distinct time-step noise generation strategies:cosine annealing and a Neural Network(NN)-based approach.We evaluate their performance across different problem scales,particularly after integrating graph structural information.Experimental results indicate that GGDS outperforms previous methods with average performance improvements of 18.7%,6.3%,and 88.7%on TSP-500,TSP-100,and TSP-50,respectively.Specifically,GGDS demonstrates superior performance on TSP-500 and TSP-50,while its performance on TSP-100 is either comparable to or slightly better than that of previous methods,depending on the chosen noise schedule and decoding strategy. 展开更多
关键词 Combinatorial optimization problem diffusion model noise schedule traveling salesman problem
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Mindfulness and internalizing/externalizing problems among adolescents:Ethnicity moderation and psychological capital mediation
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作者 Jia Wu Wei Luo +4 位作者 Qianguo Xiao Qinhong Xie Xiaodong Li Taiyong Bi Hui Kou 《Journal of Psychology in Africa》 2026年第1期97-106,共10页
This study examines the mediating role of positive psychological capital and the moderating role of ethnicity in the relationship between mindfulness and internalizing/externalizing problems among adolescents.The stud... This study examines the mediating role of positive psychological capital and the moderating role of ethnicity in the relationship between mindfulness and internalizing/externalizing problems among adolescents.The study sample comprized Chinese adolescents(N=637 ethnic minority;females=40.97%,meam age=12.68,SD=0.49 years;N=636 Han;females=49.06%,mean age=12.71,SD=0.47 years).The participants completed the Child and Adolescent Mindfulness Measure,the Positive Psycap Questionnaire,and the Youth Self-Report.Results from the moderated mediation analysis showed mindfulness was negatively associated with both internalizing and externalizing problems.Ethnicity moderated the relationship between mindfulness and internalizing problems to be stronger for Han adolescents compared to ethnic minority adolescents.Psychological capital mediated the relationship between mindfulness and internalizing problems in both groups,with a negative direction.Findings support the Conservation of Resources theory and highlight mindfulness as a personal resource fostering adolescent well-being in multicultural contexts. 展开更多
关键词 Ethnic minority adolescent MINDFULNESS positive psychological capital internalizing problems externalizing problems
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Bifurcation and Stability of Nonlinear Steklov Problems on the Unit Disk
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作者 Qingbo LIU Ruihao LIU Yingxin SUN 《Journal of Mathematical Research with Applications》 2026年第2期251-262,共12页
This paper is concerned with the following nonlinear Steklov problemΔu=0 in D,∂vu=λf(u)on∂D,where D is the unit disk in the plane,∂v denotes the unit outward normal derivative.For each k∈N,under some natural condit... This paper is concerned with the following nonlinear Steklov problemΔu=0 in D,∂vu=λf(u)on∂D,where D is the unit disk in the plane,∂v denotes the unit outward normal derivative.For each k∈N,under some natural conditions on f,using the Crandall-Rabinowitz bifurcation theorem,we obtain a bifurcation curve emanating from(k,0).Furthermore,we also analyze the local structure of bifurcation curves and stability of solutions on them.Specifically,our results indicate the bifurcation is critical for each k and is subcritical(supercritical)if f'''(0)>0(f'''(0)<0). 展开更多
关键词 teklov eigenvalue BIFURCATION STABILITY nonlinear boundary problem
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Diagnosing Organizational Bottlenecks in Student Software Projects with Extended Problem Frames
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作者 Zicheng Huang Hongbin Xiao Zhi Li 《计算机教育》 2026年第3期210-219,共10页
In educational settings,instructors often lead students through hands-on software projects,sometimes engaging two different schools or departments.How can such collaborations be made more efficient,and how can student... In educational settings,instructors often lead students through hands-on software projects,sometimes engaging two different schools or departments.How can such collaborations be made more efficient,and how can students truly experience the importance of teamwork and the impact of organizational structure on project complexity?To answer these questions,we introduce the requirement-driven organization structure(R-DOS)approach,which tightly couples software requirements with the actual development process.By extending problem-frames modeling and focusing on requirements,R-DOS allows educators and students to(1)diagnose structural flaws early,(2)prescribe role-level and communication fixes,and(3)observe-in real time-how poor structure can derail a project while good structure accelerates learning and delivery. 展开更多
关键词 Requirements engineering Organization structure problem Frames
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Solutions of three-body problem based on an equivalent system approach
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作者 Jing Tang Xing 《Acta Mechanica Sinica》 2026年第1期292-309,共18页
Generalised reduced masses with a set of equations governing the three relative motions between two of 3-bodies in their gravitational field are established,of which the dynamic characteristics of 3-body dynamics,fund... Generalised reduced masses with a set of equations governing the three relative motions between two of 3-bodies in their gravitational field are established,of which the dynamic characteristics of 3-body dynamics,fundamental bases of this paper,are revealed.Based on these findings,an equivalent system is developed,which is a 2-body system with its total mass,constant angular momentum,kinetic and potential energies same as the total ones of three relative motions,so that it can be solved using the well-known theory of the 2-body system.From the solution of an equivalent system with the revealed characteristics of three relative motions,the general theoretical solutions of the 3-body system are obtained in the curve-integration forms along the orbits in the imaged radial motion space.The possible periodical orbits with generalised Kepler’s law are presented.Following the description and mathematical demonstrations of the proposed methods,the examples including Euler’s/Lagrange’s problems,and a reported numerical one are solved to validate the proposed methods.The methods derived from the 3-body system are extended to N-body problems. 展开更多
关键词 Three-body problem Equivalent system with solutions Orbit-equation of a conic section Generalised reduced mass Chaotic motions Generalised Kepler’s law N-body problem
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The Curvilinear Relationship between Maternal-Parenting Stress and Adolescent Internalizing-Problems:Family Socioeconomic-Status and Adolescent Gender’s Moderating Roles
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作者 Xiaoting Hou Jingjing Zhao +2 位作者 Yuxin Shi Yuhua Li Shufen Xing 《International Journal of Mental Health Promotion》 2026年第3期26-37,共12页
Background:The growing parenting stress among Chinese mothers in recent years raises concerns about its impact on adolescent internalizing problems.The purpose of this study was to examine the curvilinear relationship... Background:The growing parenting stress among Chinese mothers in recent years raises concerns about its impact on adolescent internalizing problems.The purpose of this study was to examine the curvilinear relationship between maternal parenting stress and internalizing problems in adolescents,and further explore the moderating effects of family socioeconomic status(SES)and adolescent gender.Methods:Data were collected from 405 mothers and adolescents(203 boys,Meanage=12.23)across five cities(Beijing,Hebei,Shanxi,Shenzhen,and Shandong)in China,who completed self-report measures of maternal parenting stress and internalizing problems.Descriptive statistics and multiple regression analyses were conducted using SPSS 27.0.Results:Multiple regression analyses indicated that the association between maternal parenting stress2 and adolescents’internalizing problems was moderated by the interaction between gender and SES(b=−0.03,p<0.01).Specifically,a significant U-shaped relationship was observed among high-SES boys(b=0.12,t=3.89,p<0.001),with internalizing problems peaking at both low and high levels of maternal parenting stress,whereas the moderating effect of SES was not significant among girls.Conclusion:The study highlights that moderate maternal parenting stress is associated with lower internalizing problems among adolescents,particularly among high-SES boys,indicating that interventions should consider the optimal balance of parental stress and account for family socioeconomic and adolescent gender differences. 展开更多
关键词 Maternal parenting stress internalizing problems family socioeconomic status GENDER
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Sensitivity of glacial isostatic adjustment observations on 3D Earths with lateral viscosity variations:A perspective from the Forward problem
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作者 Patrick Wu 《Geodesy and Geodynamics》 2026年第1期1-11,共11页
Sensitivity of observational data is important in the study of Glacial Isostatic Adjustment(GIA).However,depending on whether sensitivity is used for the Inverse Problem or the Forward Problem,the final formulation an... Sensitivity of observational data is important in the study of Glacial Isostatic Adjustment(GIA).However,depending on whether sensitivity is used for the Inverse Problem or the Forward Problem,the final formulation and display of the sensitivity kernel will be different.Unfortunately,in the past,both perspectives give the same name to their quantity computed/displayed,and that has caused some confusion.To distinguish between the two,their perspective should be added to the names.This paper focuses only on the perspective of the Forward Problem where the input parameters are known.The Perturbation method has been successfully used in the computation of the sensitivity kernels of observations on 1D and 3D viscosity variations from the Forward perspective.One aim of this paper is to review and clarify the physics of the Perturbation method and bring out some important aspects of this method that have been misunderstood or neglected.Another aim is to present sensitivity kernels from the Perturbation method using 3D(both radially and laterally heterogeneous)Earth models with realistic ice history.These new results are now suitable for future comparison with those from new methods using the Forward perspective.Finally,the sensitivity computations for realistic ice histories on a 3D Earth is reviewed and used to search for optimal locations of new GIA observations. 展开更多
关键词 Mantle rheology Loading of the Earth Forward problem
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Micromagnetic simulation of μMAG standard problem No.3:Evaluating the standard dipole-dipole interaction
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作者 A.K.F.Silva D.C.Carvalho +1 位作者 H.S.Assis P.Z.Coura 《Chinese Physics B》 2026年第1期180-186,共7页
Cubic-shaped magnetic particles subjected to a dimensionless uniaxial anisotropy(Q=0.1)aligned with one of the crystallographic axes provide an ideal system for investigating magnetic equilibrium states.In this system... Cubic-shaped magnetic particles subjected to a dimensionless uniaxial anisotropy(Q=0.1)aligned with one of the crystallographic axes provide an ideal system for investigating magnetic equilibrium states.In this system,three fundamental magnetization configurations are identified:(i)the flower state,(ii)the twisted flower state,and(iii)the vortex state.This problem corresponds to standard problem No.3 proposed by the NIST Micromagnetics Modeling Group,widely adopted as a benchmark for validating computational micromagnetics methods.In this work,we approach the problem using a computational method based on direct dipolar interactions,in contrast to conventional techniques that typically compute the demagnetizing field via finite difference-based fast Fourier transform(FFT)methods,tensor grid approaches,or finite element formulations.Our results are compared with established literature data,focusing on the dimensionless parameterλ=L/l_(ex),where L is the cube edge length and l_(ex)is the exchange length of the material.To analyze equilibrium state transitions,we systematically varied the size L as a function of the simulation cell number N and intercellular spacing a,determining the criticalλvalue associated with configuration changes.Our simulations reveal that the transition between the twisted flower and vortex states occurs atλ≈8.45,consistent with values reported in the literature,validating our code(Grupo de Física da Matéeria Condensada-UFJF),and shows that this standard problem can be resolved using only interaction dipolar of a direct way without the need for sophisticated additional calculations. 展开更多
关键词 micromagnetic simulation standard problem No.3 dipolar interaction
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Collaborative scheduling problem pertaining to launch and recovery operations for carrier aircraft
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作者 GUO Fang HAN Wei +3 位作者 LIU Yujie SU Xichao LIU Jie LI Changjiu 《Journal of Systems Engineering and Electronics》 2026年第1期287-306,共20页
The proliferation of carrier aircraft and the integration of unmanned aerial vehicles(UAVs)on aircraft carriers present new challenges to the automation of launch and recovery operations.This paper investigates a coll... The proliferation of carrier aircraft and the integration of unmanned aerial vehicles(UAVs)on aircraft carriers present new challenges to the automation of launch and recovery operations.This paper investigates a collaborative scheduling problem inherent to the operational processes of carrier aircraft,where launch and recovery tasks are conducted concurrently on the flight deck.The objective is to minimize the cumulative weighted waiting time in the air for recovering aircraft and the cumulative weighted delay time for launching aircraft.To tackle this challenge,a multiple population self-adaptive differential evolution(MPSADE)algorithm is proposed.This method features a self-adaptive parameter updating mechanism that is contingent upon population diversity,an asynchronous updating scheme,an individual migration operator,and a global crossover mechanism.Additionally,comprehensive experiments are conducted to validate the effectiveness of the proposed model and algorithm.Ultimately,a comparative analysis with existing operation modes confirms the enhanced efficiency of the collaborative operation mode. 展开更多
关键词 carrier aircraft collaborative scheduling problem LAUNCH RECOVERY multiple population differential evolution
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Somatization and Eating Problems in Adolescents in Residential Care: The Influence of Relational Trauma, Attachment, Gender, and Personal Resources
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作者 Laura Lacomba-Trejo Francisco González-Sala +1 位作者 Sandra Simó Florencia Talmón-Knuser 《International Journal of Mental Health Promotion》 2026年第3期38-58,共21页
Backgrounds:Somatization and eating-related problems in adolescents living in residential care may be shaped by the interplay of risk and protective factors,including gender,relational trauma,attachment patterns,emoti... Backgrounds:Somatization and eating-related problems in adolescents living in residential care may be shaped by the interplay of risk and protective factors,including gender,relational trauma,attachment patterns,emotional intelligence,and perceived social support.This study examined how gender,relational trauma,attachment dimensions,resilience,and emotional intelligence contribute to the presence of somatic and eating difficulties in this population.Methods:The sample included 46 adolescents(63%female;ages 12–17,Mean=14.85,Standard Deviation(SD)=1.49)residing in child protection institutions in Uruguay.Participants completed self-report measures assessing childhood relational trauma(CaMir),attachment dimensions(anxiety and avoidance),resilience,emotional intelligence(adaptability and stress management),social support(MOS),and psychosocial adjustment(SENA subscales of somatization and eating problems).Using a fuzzy-set Qualitative Comparative Analysis(fsQCA)approach,distinct configurations of risk and protective factors associated with elevated levels of somatization and eating problems were identified.Results:Relational trauma and attachment anxiety showed moderate associations with both somatization and eating problems(r=0.52–0.57,p<0.01),whereas stress management was negatively associated with both outcomes(r=−0.37 to−0.47,p<0.05).FsQCA revealed multiple configurations of risk and protective factors explaining 81–90%of cases,with solution consistencies ranging from 0.83 to 0.87.Results suggest that relational trauma and attachment anxiety are key risk conditions,whereas resilience,emotional regulation,and perceived social support function as protective factors.Conclusions:Findings highlight the importance of considering multifactorial patterns of vulnerability and protection rather than single predictors and underscore the need for tailored interventions that strengthen resilience and emotional skills while addressing the impact of early relational trauma. 展开更多
关键词 Residential care SOMATIZATION eating problems relational trauma RESILIENCE emotional intelligence social support
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NONLINEAR RIEMANN AND HILBERT BOUNDARY VALUE PROBLEMS WITH SQUARE ROOTS IN VARIABLE EXPONENT SPACES
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作者 Yajun Hu Fuli He 《Acta Mathematica Scientia》 2026年第1期1-18,共18页
In this paper,we study the nonlinear Riemann boundary value problem with square roots that is represented by a Cauchy-type integral with kernel density in variable exponent Lebesgue spaces.We discuss the odd-order zer... In this paper,we study the nonlinear Riemann boundary value problem with square roots that is represented by a Cauchy-type integral with kernel density in variable exponent Lebesgue spaces.We discuss the odd-order zero-points distribution of the solutions and separate the single valued analytic branch of the solutions with square roots,then convert the problem to a Riemann boundary value problem in variable exponent Lebesgue spaces and discuss the singularity of solutions at individual zeros belonging to curve.We consider two types of cases those where the coefficient is Hölder and those where it is piecewise Hölder.Then we solve the Hilbert boundary value problem with square roots in variable exponent Lebesgue spaces.By discussing the distribution of the odd-order zero-points for solutions and the method of symmetric extension,we convert the Hilbert problem to a Riemann boundary value problem.The equivalence of the transformation is discussed.Finally,we get the solvable conditions and the direct expressions of the solutions in variable exponent Lebesgue spaces. 展开更多
关键词 boundary value problem Cauchy-type integral variable exponent spaces non-linearity piecewise Lyapunov curve
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Precedence Criteria and Gradient-Based Scheduling Algorithm for the Airplane Refueling Problem
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作者 LIN Hao HE Cheng 《Chinese Quarterly Journal of Mathematics》 2026年第1期38-49,共12页
The airplane refueling problem can be stated as follows.We are given n airplanes which can refuel one another during the flight.Each airplane has a reservoir volume wj(liters)and a consumption rate pj(liters per kilom... The airplane refueling problem can be stated as follows.We are given n airplanes which can refuel one another during the flight.Each airplane has a reservoir volume wj(liters)and a consumption rate pj(liters per kilometer).As soon as one airplane runs out of fuel,it is dropping out of the flight.The problem asks for finding a refueling scheme such that the last plane in the air reach a maximal distance.An equivalent version is the n-vehicle exploration problem.The computational complexity of this non-linear combinatorial optimization problem is open so far.This paper employs the neighborhood exchange method of single-machine scheduling to study the precedence relations of jobs,so as to improve the necessary and sufficiency conditions of optimal solutions,and establish an efficient heuristic algorithm which is a generalization of several existing special algorithms. 展开更多
关键词 Combinatorial optimization Scheduling method The airplane refueling problem Optimality criteria Heuristic algorithm
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Design and Validation of Zeroing Neural Network With Active Noise Rejection Capability for Time-Varying Problems Solving
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作者 Yilin Shang Wenbo Zhang +1 位作者 Dongsheng Guo Shan Xue 《CAAI Transactions on Intelligence Technology》 2026年第1期256-266,共11页
Recently,the zeroing neural network(ZNN)has demonstrated remarkable effectiveness in tackling time-varying problems,delivering robust performance across both noise-free and noisy environments.However,existing ZNN mode... Recently,the zeroing neural network(ZNN)has demonstrated remarkable effectiveness in tackling time-varying problems,delivering robust performance across both noise-free and noisy environments.However,existing ZNN models are limited in their ability to actively suppress noise,which constrains their robustness and precision in solving time-varying problems.This paper introduces a novel active noise rejection ZNN(ANR-ZNN)design that enhances noise suppression by integrating computational error dynamics and harmonic behaviour.Through rigorous theoretical analysis,we demonstrate that the proposed ANR-ZNN maintains robust convergence in computational error performance under environmental noise.As a case study,the ANR-ZNN model is specifically applied to time-varying matrix inversion.Comprehensive computer simulations and robotic experiments further validate the ANR-ZNN's effectiveness,emphasising the proposed design's superiority and potential for solving time-varying problems. 展开更多
关键词 active noise rejection matrix inversion robot application time-varying problems zeroing neural network
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Centralized Circumcentered-Reflection Method for Solving the Convex Feasibility Problem in Sparse Signal Recovery
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作者 Chunmei LI Bangjun CHEN Xuefeng DUAN 《Journal of Mathematical Research with Applications》 2026年第1期119-133,共15页
Convex feasibility problems are widely used in image reconstruction, sparse signal recovery, and other areas. This paper is devoted to considering a class of convex feasibility problem arising from sparse signal recov... Convex feasibility problems are widely used in image reconstruction, sparse signal recovery, and other areas. This paper is devoted to considering a class of convex feasibility problem arising from sparse signal recovery. We first derive the projection formulas for a vector onto the feasible sets. The centralized circumcentered-reflection method is designed to solve the convex feasibility problem. Some numerical experiments demonstrate the feasibility and effectiveness of the proposed algorithm, showing superior performance compared to conventional alternating projection methods. 展开更多
关键词 convex feasibility problem centralized circumcentered-re ection method sparse signal recovery compressed sensing
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Quality-guaranteed Dubins Path Planning for USV Based on Mixed-integer Piecewise linear Programming for Addressing the Extended Minimum-time Intercept Problem
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作者 Xing Zhou Kelin Zhu +3 位作者 Shuang Liu Zhaoqing Li Wenxin Zhang Kang Du 《哈尔滨工程大学学报(英文版)》 2026年第1期216-227,共12页
During the use of robotics in applications such as antiterrorism or combat,a motion-constrained pursuer vehicle,such as a Dubins unmanned surface vehicle(USV),must get close enough(within a prescribed zero or positive... During the use of robotics in applications such as antiterrorism or combat,a motion-constrained pursuer vehicle,such as a Dubins unmanned surface vehicle(USV),must get close enough(within a prescribed zero or positive distance)to a moving target as quickly as possible,resulting in the extended minimum-time intercept problem(EMTIP).Existing research has primarily focused on the zero-distance intercept problem,MTIP,establishing the necessary or sufficient conditions for MTIP optimality,and utilizing analytic algorithms,such as root-finding algorithms,to calculate the optimal solutions.However,these approaches depend heavily on the properties of the analytic algorithm,making them inapplicable when problem settings change,such as in the case of a positive effective range or complicated target motions outside uniform rectilinear motion.In this study,an approach employing a high-accuracy and quality-guaranteed mixed-integer piecewise-linear program(QG-PWL)is proposed for the EMTIP.This program can accommodate different effective interception ranges and complicated target motions(variable velocity or complicated trajectories).The high accuracy and quality guarantees of QG-PWL originate from elegant strategies such as piecewise linearization and other developed operation strategies.The approximate error in the intercept path length is proved to be bounded to h^(2)/(4√2),where h is the piecewise length. 展开更多
关键词 Minimum-time intercept problem Dubins vehicle Mixed-integer piecewise-linear program LINEARIZATION Approximate error trigonometric function USV
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Cooperative Metaheuristics with Dynamic Dimension Reduction for High-Dimensional Optimization Problems
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作者 Junxiang Li Zhipeng Dong +2 位作者 Ben Han Jianqiao Chen Xinxin Zhang 《Computers, Materials & Continua》 2026年第1期1484-1502,共19页
Owing to their global search capabilities and gradient-free operation,metaheuristic algorithms are widely applied to a wide range of optimization problems.However,their computational demands become prohibitive when ta... Owing to their global search capabilities and gradient-free operation,metaheuristic algorithms are widely applied to a wide range of optimization problems.However,their computational demands become prohibitive when tackling high-dimensional optimization challenges.To effectively address these challenges,this study introduces cooperative metaheuristics integrating dynamic dimension reduction(DR).Building upon particle swarm optimization(PSO)and differential evolution(DE),the proposed cooperative methods C-PSO and C-DE are developed.In the proposed methods,the modified principal components analysis(PCA)is utilized to reduce the dimension of design variables,thereby decreasing computational costs.The dynamic DR strategy implements periodic execution of modified PCA after a fixed number of iterations,resulting in the important dimensions being dynamically identified.Compared with the static one,the dynamic DR strategy can achieve precise identification of important dimensions,thereby enabling accelerated convergence toward optimal solutions.Furthermore,the influence of cumulative contribution rate thresholds on optimization problems with different dimensions is investigated.Metaheuristic algorithms(PSO,DE)and cooperative metaheuristics(C-PSO,C-DE)are examined by 15 benchmark functions and two engineering design problems(speed reducer and composite pressure vessel).Comparative results demonstrate that the cooperative methods achieve significantly superior performance compared to standard methods in both solution accuracy and computational efficiency.Compared to standard metaheuristic algorithms,cooperative metaheuristics achieve a reduction in computational cost of at least 40%.The cooperative metaheuristics can be effectively used to tackle both high-dimensional unconstrained and constrained optimization problems. 展开更多
关键词 Dimension reduction modified principal components analysis high-dimensional optimization problems cooperative metaheuristics metaheuristic algorithms
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Non-Newtonian rivulet flows on an inclined planar surface applying the 2nd Stokes problem
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作者 S.V.ERSHKOV E.S.BARANOVSKII A.V.YUDIN 《Applied Mathematics and Mechanics(English Edition)》 2026年第1期153-164,共12页
The newly formulated non-Newtonian rivulet flows streaming down an inclined planar surface,with additional periodic perturbations arising from the application of the 2nd Stokes problem to the investigation of rivulet ... The newly formulated non-Newtonian rivulet flows streaming down an inclined planar surface,with additional periodic perturbations arising from the application of the 2nd Stokes problem to the investigation of rivulet dynamics,are demonstrated in the current research.Hereby,the 2nd Stokes problem assumes that the surface,with a thin shared layer of the fluid on it,oscillates in a harmonic manner along the x-axis of the rivulet flow,which coincides with the main flow direction streaming down the underlying surface.We obtain the exact extension of the rivulet flow family,clarifying the structure of the pressure field,which fully absorbs the arising perturbation.The profile of the velocity field is assumed to be Gaussian-type with a non-zero level of plasticity.Hence,the absolutely non-Newtonian case of the viscoplastic flow solution,which satisfies the motion and continuity equations,is considered(with particular cases of exact solutions for pressure).The perturbed governing equations of motion for rivulet flows then result in the Riccati-type ordinary differential equation(ODE),describing the dynamics of the coordinate x(t).The approximated schematic dynamics are presented in graphical plots. 展开更多
关键词 rivulet flow non-Newtonian fluid creeping viscoplastic flow 1st/2nd Stokes problem
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Neural boundary shape functions in physics-informed neural networks for discontinuous and high-frequency problems
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作者 P.T.NGUYEN K.A.LUONG J.H.LEE 《Applied Mathematics and Mechanics(English Edition)》 2026年第2期423-442,共20页
Physics-informed neural networks(PINNs)have been shown as powerful tools for solving partial differential equations(PDEs)by embedding physical laws into the network training.Despite their remarkable results,complicate... Physics-informed neural networks(PINNs)have been shown as powerful tools for solving partial differential equations(PDEs)by embedding physical laws into the network training.Despite their remarkable results,complicated problems such as irregular boundary conditions(BCs)and discontinuous or high-frequency behaviors remain persistent challenges for PINNs.For these reasons,we propose a novel two-phase framework,where a neural network is first trained to represent shape functions that can capture the irregularity of BCs in the first phase,and then these neural network-based shape functions are used to construct boundary shape functions(BSFs)that exactly satisfy both essential and natural BCs in PINNs in the second phase.This scheme is integrated into both the strong-form and energy PINN approaches,thereby improving the quality of solution prediction in the cases of irregular BCs.In addition,this study examines the benefits and limitations of these approaches in handling discontinuous and high-frequency problems.Overall,our method offers a unified and flexible solution framework that addresses key limitations of existing PINN methods with higher accuracy and stability for general PDE problems in solid mechanics. 展开更多
关键词 physics-informed neural network(PINN) boundary shape function(BSF) strong-form approach energy approach DISCONTINUITY high-frequency problem
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