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Parametric resonance of axially functionally graded pipes conveying pulsating fluid

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Applied mathematics and Mechanics(English Edition) 2024年第2期45卷 239-260页

作者： Jie JING Xiaoye MAO Hu DING Liqun CHEN Shanghai Key Laboratory of Mechanics in Energy Engineering Shanghai Frontier Science Center of MechanoinformaticsShanghai Institute of Applied Mathematics and MechanicsSchool of Mechanics and Engineering ScienceShanghai UniversityShanghai 200444China Shanghai institute of Aircraft Mechanics and Control Shanghai 200092China

Based on the generalized Hamilton's principle,the nonlinear governing equation of an axially functionally graded(AFG)pipe is *** non-trivial equilibrium configuration is superposed by the modal functions of a simply supported *** the direct multi-scale method,the response and stability boundary to the pulsating fluid velocity are solved analytically and verified by the differential quadrature element method(DQEM).The influence of Young's modulus gradient on the parametric resonance is investigated in the subcritical and supercritical *** general,the pipe in the supercritical region is more sensitive to the pulsating *** nonlinearity changes from hard to soft,and the non-trivial equilibrium configuration introduces more frequency components to the ***,the increasing Young's modulus gradient improves the critical pulsating flow velocity of the parametric resonance,and further enhances the stability of the *** addition,when the temperature increases along the axial direction,reducing the gradient parameter can enhance the response *** work further complements the theoretical analysis of pipes conveying pulsating fluid.

关键词： pipe conveying fluid axially functionally graded supercritical resonance multi-scale method parametric resonance

A polynomial resultant approach to algebraic constructions of extremal graphs

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Science China mathematics 2024年

作者： Tao Zhang Zixiang Xu Gennian Ge institute of mathematics and Interdisciplinary Sciences Xidian University school of Mathematical Sciences Capital Normal University

The Turan problem asks for the largest number of edges ex（n, H） in an n-vertex graph not containing a fixed forbidden subgraph H, which is one of the most important problems in extremal graph theory. However,the order of magnitude of ex（n, H） for bipartite graphs is known only in a handful of cases. In particular,giving explicit constructions of extremal graphs is very challenging in this field. In this paper, we develop a polynomial resultant approach to the algebraic construction of explicit extremal graphs, which can efficiently decide whether a specified structure exists. A key insight in our approach is the multipolynomial resultant, which is a fundamental tool of computational algebraic geometry. Our main results include the matched lower bounds on the Turan number of 1-subdivision of K3,t1and the linear Turan number of the Berge theta hypergraphΘ3B,t2, where t1= 25 and t2= 217. Moreover, the constant t1 improves the random algebraic construction of Bukh and Conlon（2018） and makes the known estimation better on the smallest value of t1 concerning a problem posed by Conlon et al.（2021） by reducing the value from a magnitude of 1056 to the number 25, while the constant t2improves a result of He and Tait（2019）.

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Aubry-Mather theory for contact Hamiltonian systems III

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Science China mathematics 2024年

作者： Panrui Ni Lin Wang Shanghai Center for Mathematical Sciences Fudan University school of mathematics and Statistics Beijing Institute of Technology

By exploiting the contact Hamiltonian dynamics(T*M × R, Φt) around the Aubry set of contact Hamiltonian systems, we provide a relation among the Mather set, the Φt-recurrent set, the strongly static set,the Aubry set, the Ma?ne′ set, and the Φt-non-wandering set. Moreover, we consider the strongly static set, as a new flow-invariant set between the Mather set and the Aubry set in the strictly increasing case. We show that this set plays an essential role in the representation of certain minimal forward weak Kolmogorov-Arnold-Moser(KAM) solutions and the existence of transitive orbits around the Aubry set.

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Monogamy and polygamy for the generalized W-class states using unified-(q,s)entropy

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Science China(Physics,Mechanics & Astronomy) 2024年第1期67卷 10-22页

作者： Bo Li Bing Xie Zhanjun Zhang Heng Fan school of Computer and Computing Science Hangzhou City UniversityHangzhou 310015China Department of mathematics East China University of TechnologyNanchang 330013China school of Information&Electronic Engineering(Sussex Artificial Intelligence institute) Zhejiang Gongshang UniversityHangzhou 310018China institute of Physics Chinese Academy of SciencesBeijing 100190China

We describe the entanglement distribution and restricted shareability of the multipartite generalized W-class states and their reduced density matrix under arbitrary partitions by using monogamy and polygamy relation based on the unified-(q,s)***,we provide an analytical formula of unified-(q,s)entanglement(UE)and an analytical lower bound of unified-(q,s)entanglement of assistance(UEo A)for a reduced density matrix of a generalized W-class ***,we use these two analytical formulas to derive the monogamy and polygamy inequalities for a reduced density matrix of a qudit generalized W-class(GW)*** establish two partition-dependent residual entanglements based on the new monogamy relation,which is helpful to obtain a comprehensive analysis of entanglement dynamics of generalized W-class ***,we investigate tighter monogamy and polygamy relations based on the power ofαth(α≥0)for UE andβth(β≥0)for UEo A,*** results show that the entanglement distribution characteristics of generalized W-class states satisfying stronger constraints can be described more accurately.

关键词： monogamy polygamy multiqudit unified entropy

On von Neumann Regularity of Commutators

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Algebra Colloquium 2024年第2期31卷 181-198页

作者： Nam Kyun Kim Tai Keun Kwak Yang Lee Sung Ju Ryu Nanqing Ding school of Basic Sciences Hanbat National UniversityDaejeon 34158Korea Department of Data Science Daejin UniversityPocheon 11159Korea Department of mathematics Yanbian UniversityYanjiJilin 133002China institute for Applied mathematics and Optics Hanbat National University Daejeon 34158Korea Department of mathematics Pusan National UniversityBusan 46241Korea 不详

We study the structure of rings which satisfy the von Neumann regularity of commutators,and call a ring R C-regularif ab-ba ∈(ab-ba)R(ab-ba)for all a,b in *** a C-regular ring R,we prove J(R[X])=N^(*)(R[X])=N^(*)(R)[X]=W(R)[X]■Z(R[X]),where J(A),N^(*)(A),W(A),Z(A)are the Jacobson radical,upper nilradical,Wedderburn radical,and center of a given ring A,respectively,and A[X]denotes the polynomial ring with a set X of commuting indeterminates over A;we also prove that R is semiprime if and only if the right(left)singular ideal of R is *** provide methods to construct C-regular rings which are neither commutative nor von Neumann regular,from any given ***,for a C-regular ring R,the following are proved to be equivalent:(i)R is Abelian;(ii)every prime factor ring of R is a duo domain;(ii)R is quasi-duo;and(iv)R/W(R)is reduced.

关键词： C-regular ring commutator regular ring commutative ring radical singular ideal

Optimal liquidation with dynamic parameter updating: A forward approach

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Probability, Uncertainty and Quantitative Risk 2024年第2期9卷 235-262页

作者： Haoran Wang Thaleia Zariphopoulou 1444 Warren Street Jersey CityNew Jersey07302USA Departments of mathematics and IROM McCombs School of BusinessThe University of Teras at AustinAustinTX 78712USA Orford-Man institute Quantitative finance University of OrfordOafordOX26EDUK

We propose a forward approach to study the performance of liquidation strategies under sequential model parameter *** forward liquidation program consists of pasting forward in time and in a time-consistent fashion a series of optimal liquidation *** are triggered at the parameter shift instances,thus entirely eliminating model error,and last at most till the next parameter ***,due to the nature of the model dynamics,solutions may cease to exist in finite time,even before the subsequent parameter ***,forward liquidation strategies may never lead to full liquidation,even though they maximize the average utility of revenue and always preserve *** juxtaposition,the traditional approach delivers full liquidation at the sought horizon but encounters considerable model error,generates value erosion,and is time-inconsistent.

关键词： Optimal liquidation Dynamic parameter updating Forward approach Full liquidation Time consistency Backward approach Expected utility model

Threshold Selection and Resource Allocation for Quantized Identification

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Journal of Systems Science & Complexity 2024年第1期37卷 204-229页

作者： WANG Ying LI Xin ZHAO Yanlong ZHANG Ji-Feng Key Laboratory of Systems and Control Institute of Systems ScienceAcademy of Mathematics and Systems ScienceChinese Academy of SciencesBeijing 100190China school of Mathematical Sciences University of Chinese Academy of SciencesBeijing 100049China

This paper is concerned with the optimal threshold selection and resource allocation problems of quantized identification, whose aims are improving identification efficiency under limited resources. Firstly, the first-order asymptotically optimal quantized identification theory is extended to the weak persistent excitation condition. Secondly, the characteristics of time and space complexities are established based on the Cramér-Rao lower bound of quantized systems. On these basis, the optimal selection methods of fixed thresholds and adaptive thresholds are established under aperiodic signals, which answer how to achieve the best efficiency of quantized identification under the same time and space complexity. In addition, based on the principle of maximizing the identification efficiency under a given resource, the optimal resource allocation methods of quantized identification are given for the cases of fixed thresholds and adaptive thresholds, respectively, which show how to balance time and space complexity to realize the best identification efficiency of quantized identification.

关键词： Quantized output resource allocation system identification threshold selection.

Tamed EM method for a delayed Ait-Sahalia type model driven by Poisson jumps

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Acta Mathematica Sinica,English Series 2024年

作者： Li TAN Sheng Rong WANG school of Statistics and Data Science Jiangxi University of Finance and Economics Key Laboratory of Data Science in finance and Economics Jiangxi University of Finance and Economics College of Modern Economics and Management of Jiangxi University of finance and Economics

In this paper, we consider a delayed Ait-Sahalia type model driven by Poisson jumps. The analytical properties including uniqueness, positiveness and boundedness of the true solution to this model are investigated. Since the coefficients are sup-linear, a tamed Euler-Maruyama(EM) method is constructed, and it is shown that the tamed EM solution converges strongly to the true solution.

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Principal Model Analysis Based on Bagging PLS and PCA and Its Application in Financial Statement Fraud

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Journal of Systems Science and Information 2024年第2期12卷 212-228页

作者： Xiao LIANG Qiwei XIE Chunyan LUO Liang TANG Yi SUN school of Economics and Management Beijing University of TechnologyBeijing 100124China Shanghai Tongtu Semiconductor Technology Co. LtdShanghai 210203China school of finance Anhui University of Finance&EconomicsBengbu 233000China

Motivated by the Bagging Partial Least Squares(Bagging PLS)and Principal Component Analysis(PCA)algorithms,a novel approach known as Principal Model Analysis(PMA)method is introduced in this *** the proposed PMA algorithm,the PCA and the Bagging PLS are *** this method,multiple PLS models are trained on sub-training sets,derived from the training set using the random sampling with replacement *** regression coefficients of all the sub-PLS models are fused in a joint regression coefficient *** final projection direction is then estimated by performing the PCA on the joint regression coefficient ***,the proposed PMA method is compared with other traditional dimension reduction methods,such as PLS,Bagging PLS,Linear discriminant analysis(LDA)and *** results on six public datasets demonstrate that our proposed method consistently outperforms other approaches in terms of classification performance and exhibits greater ***,it is employed in the application of financial statement fraud *** and other five algorithms are utilized to financial statement fraud which concerned by the academic community,and the results indicate that the classification of PMA surpassed that of the other methods.

关键词： principal model analysis partial least squares principal component analysis dimension reduction ensemble learning financial statement fraud detection