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A SHARP ESTIMATE ON THE DEGREE OF APPROXIMATION TO FUNCTIONS OF BOUNDED VARIATION BY CERTAIN OPERATORS 被引量:1
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作者 Vijay Gupta 《Analysis in Theory and Applications》 1995年第3期106-107,共2页
Recently Guo introduced integrated Meyer -Konig and Zeller operators and studied the rate of convergence for function of bounded variation. In this note we give a sharp estimate for these operators.
关键词 A SHARP ESTIMATE ON THE DEGREE OF approximation TO FUNCTIONS OF BOUNDED variatION BY CERTAIN OPERATORS
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Variational Approach to 2D and 3D Heat Conduction Modeling
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作者 Slavko Đurić Ivan Aranđelović Milan Milotić 《Journal of Applied Mathematics and Physics》 2024年第4期1383-1400,共18页
The paper proposes an approximate solution to the classical (parabolic) multidimensional 2D and 3D heat conduction equation for a 5 × 5 cm aluminium plate and a 5 × 5 × 5 cm aluminum cube. An approximat... The paper proposes an approximate solution to the classical (parabolic) multidimensional 2D and 3D heat conduction equation for a 5 × 5 cm aluminium plate and a 5 × 5 × 5 cm aluminum cube. An approximate solution of the generalized (hyperbolic) 2D and 3D equation for the considered plate and cube is also proposed. Approximate solutions were obtained by applying calculus of variations and Euler-Lagrange equations. In order to verify the correctness of the proposed approximate solutions, they were compared with the exact solutions of parabolic and hyperbolic equations. The paper also presents the research on the influence of time parameters τ as well as the relaxation times τ ∗ to the variation of the profile of the temperature field for the considered aluminum plate and cube. 展开更多
关键词 Classical Equation of Heat Conduction Generalized Equation of Heat Conduction Calculus of variations approximate Solution
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D_∞-APPROXIMATION OF PRODUCT VARIATIONS OF TWO PARAMETER SMOOTH SEMIMARTINGALES
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作者 刘继成 《Acta Mathematica Scientia》 SCIE CSCD 2004年第2期235-246,共12页
Let X be a two parameter smooth semimartingale and (?) be its process of the product variation. It is proved that (?) can be approximated as D_∞-limit of sums of its discrete product variations as the mesh of divisio... Let X be a two parameter smooth semimartingale and (?) be its process of the product variation. It is proved that (?) can be approximated as D_∞-limit of sums of its discrete product variations as the mesh of division tends to zero. Moreover, this result can be strengthen to yield the quasi sure convergence of sums by estimating the speed of the convergence. 展开更多
关键词 Malliavin calculus D_∞-approximation two parameter smooth semimartingale product variation quasi sure
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Muntz Rational Approximation for Special Function Classes in Orlicz Spaces 被引量:1
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作者 Ruifang Yu Garide Wu 《Analysis in Theory and Applications》 CSCD 2017年第1期20-28,共9页
Using the method of construction, with the help of inequalities, we research the Muntz rational approximation of two kinds of special function classes, and give the corresponding estimates of approximation rates of th... Using the method of construction, with the help of inequalities, we research the Muntz rational approximation of two kinds of special function classes, and give the corresponding estimates of approximation rates of these classes under widely con- ditions. Because of the Orlicz Spaces is bigger than continuous function space and the Lp space, so the results of this paper has a certain expansion significance. 展开更多
关键词 Muntz rational approximation bounded variation function class Sobolev functionclass Orlicz space.
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ON A FAMILY OF MULTIVARIATE LEAST-SQUARES ORTHOGONAL POLYNOMIALS 被引量:1
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作者 郑成德 王仁宏 《Numerical Mathematics A Journal of Chinese Universities(English Series)》 SCIE 2003年第1期51-58,共8页
In this paper the new notion of multivariate least-squares orthogonal poly-nomials from the rectangular form is introduced. Their existence and uniqueness isstudied and some methods for their recursive computation are... In this paper the new notion of multivariate least-squares orthogonal poly-nomials from the rectangular form is introduced. Their existence and uniqueness isstudied and some methods for their recursive computation are given. As an applica-is constructed. 展开更多
关键词 线性代数 正交多项式 多元最小二乘方 递归计算 多元近似
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MNTZ RATIONAL APPROXIMATION FOR SPECIAL FUNCTION CLASSES IN Ba[0,1] SPACES
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作者 Zhenghua Kang Garidi Wu 《Analysis in Theory and Applications》 2012年第1期87-94,共8页
In this paper, we research the Miintz rational approximation of two kinds of spe- cial function classes, and give the corresponding estimates of approximation rates of these classes.
关键词 Muntz rational approximation bounded variation function class Sobolevfunction class approximation rate
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Comparison of two approximal proximal point algorithms for monotone variational inequalities 被引量:1
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作者 TAO Min 《Journal of Zhejiang University-Science A(Applied Physics & Engineering)》 SCIE EI CAS CSCD 2007年第6期969-977,共9页
Proximal point algorithms (PPA) are attractive methods for solving monotone variational inequalities (MVI). Since solving the sub-problem exactly in each iteration is costly or sometimes impossible, various approximat... Proximal point algorithms (PPA) are attractive methods for solving monotone variational inequalities (MVI). Since solving the sub-problem exactly in each iteration is costly or sometimes impossible, various approximate versions of PPA (APPA) are developed for practical applications. In this paper, we compare two APPA methods, both of which can be viewed as predic- tion-correction methods. The only difference is that they use different search directions in the correction-step. By extending the general forward-backward splitting methods, we obtain Algorithm I; in the same way, Algorithm II is proposed by spreading the general extra-gradient methods. Our analysis explains theoretically why Algorithm II usually outperforms Algorithm I. For computation practice, we consider a class of MVI with a special structure, and choose the extending Algorithm II to implement, which is inspired by the idea of Gauss-Seidel iteration method making full use of information about the latest iteration. And in particular, self-adaptive techniques are adopted to adjust relevant parameters for faster convergence. Finally, some nu- merical experiments are reported on the separated MVI. Numerical results showed that the extending Algorithm II is feasible and easy to implement with relatively low computation load. 展开更多
关键词 单调变分不等式 近似邻近点算法 比较 预测 校正
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Continuous Piecewise Linear Approximation of BV Function
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作者 Hua Yi Tao Yu +1 位作者 Zhiquan Chen Jingwen Zhu 《Applied Mathematics》 2014年第4期667-671,共5页
Nonlinear approximation is widely used in signal processing. Real-life signals can be modeled as functions of bounded variation. Thus the variable knot of approximating function could be self- adaptively chosen by bal... Nonlinear approximation is widely used in signal processing. Real-life signals can be modeled as functions of bounded variation. Thus the variable knot of approximating function could be self- adaptively chosen by balancing the total variation of the target function. In this paper, we adopt continuous piecewise linear approximation instead of the existing piecewise constants approximation. The results of experiments show that this new method is superior to the old one. 展开更多
关键词 Nonlinear approximation BOUNDED variation CONTINUOUS PIECEWISE Linear BASIS FUNCTION PIECEWISE Constant BASIS FUNCTION Compression DENOISING
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基于VMD-LILGWO-LSSVM短期风电功率预测
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作者 王瑞 李虹锐 +1 位作者 逯静 卜旭辉 《河南理工大学学报(自然科学版)》 CAS 北大核心 2024年第2期128-136,共9页
目的为了减小风电功率并入国家电网时产生的频率波动,提高风电功率预测精度,方法提出一种结合变分模态分解(VMD)、改进灰狼算法(LILGWO)和最小二乘支持向量机(LSSVM)的风电功率短期预测方法。首先通过VMD方法将风电功率序列分解重构成3... 目的为了减小风电功率并入国家电网时产生的频率波动,提高风电功率预测精度,方法提出一种结合变分模态分解(VMD)、改进灰狼算法(LILGWO)和最小二乘支持向量机(LSSVM)的风电功率短期预测方法。首先通过VMD方法将风电功率序列分解重构成3个复杂程度性不同的模态分量,降低风电功率的波动性;其次使用LSSVM挖掘各分量的特征信息,对各分量分别进行预测,针对LSSVM模型中重要参数的选取对预测精度影响较大问题,引入LILGWO对参数进行寻优;最后将各分量预测结果叠加重构,得到最终预测风电功率。结果以宁夏回族自治区某地区风电站实际数据为例,对未来三天分别进行预测取平均值,本文方法的预测平均绝对误差(mean absolute error,MAE)为2.7068 kW,均方根误差(root mean square error,RMSE)为2.0211,拟合程度决定系数(R-Square,R^(2))为0.9769,与对比方法3~6相比,RMSE分别降低了40.93%,25.21%,14.7%,6.24%;MAE分别降低了42.34%,28.04%,16.97%,7.77%;R^(2)分别提升了4.21%,1.78%,0.82%,0.28%。预测时长方面,BP和LSSVM平均训练时间分别是10,138 s,虽然LSSVM预测时间较长但效果最好,采用PSO、GWO、LILGWO对LSSVM进行寻优后训练时间分别平均缩短了39,44,58 s。结论仿真验证了所提方法在短期风电功率预测方面的有效性。 展开更多
关键词 风电功率 短期预测 变分模态分解 近似熵 改进灰狼算法 最小二乘支持向量机
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基于变分自编码器的近似聚合查询优化方法
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作者 黄龙森 房俊 +1 位作者 周云亮 郭志城 《浙江大学学报(工学版)》 EI CAS CSCD 北大核心 2024年第5期931-940,共10页
针对偏态数据分布不平衡,传统近似聚合查询方法难以抽样生成偏态分布数据的问题,提出基于优化的变分自编码器的近似聚合查询方法,研究近似聚合查询方法对偏态分布数据的近似聚合查询准确率的影响.在预处理阶段对偏态分布数据进行分层分... 针对偏态数据分布不平衡,传统近似聚合查询方法难以抽样生成偏态分布数据的问题,提出基于优化的变分自编码器的近似聚合查询方法,研究近似聚合查询方法对偏态分布数据的近似聚合查询准确率的影响.在预处理阶段对偏态分布数据进行分层分组,对变分自编码器生成模型的网络结构和损失函数进行优化,降低近似聚合查询相对误差.实验结果表明,与基准方法相比,近似聚合查询对偏态分布数据的查询相对误差更小,且随着偏态系数的提高,查询相对误差的上升趋势更平缓. 展开更多
关键词 近似查询处理 偏态分布 机器学习 变分自编码器 分组抽样
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量子计算技术在新型电力系统决策优化中的应用 被引量:1
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作者 李知艺 许悦 韩旭涛 《电力系统自动化》 EI CSCD 北大核心 2024年第6期62-73,共12页
新型电力系统的规划、运行和市场运营等决策优化过程呈现变量激增、约束繁杂等特点,而量子计算具有运算并行和状态叠加等特性,为高效解决此类“维数灾难”难题提供了新的技术路径。文中围绕量子计算技术赋能新型电力系统决策优化的原理... 新型电力系统的规划、运行和市场运营等决策优化过程呈现变量激增、约束繁杂等特点,而量子计算具有运算并行和状态叠加等特性,为高效解决此类“维数灾难”难题提供了新的技术路径。文中围绕量子计算技术赋能新型电力系统决策优化的原理可行性及实现思路展开探析。首先,梳理分析量子计算应用于新型电力系统决策优化过程的先进性与局限性,构建量子-经典计算混合的变分量子决策优化框架。在此基础上,提炼新型电力系统典型优化问题的共性,推导统一的问题结构,形成可利用量子比特系统描述的能量模型。随后,提出基于量子近似优化算法的求解流程,寻找能量模型的极值,并映射得到原优化问题的最优解。最后,从软硬件、算法框架以及行业发展等角度提出思考与展望。 展开更多
关键词 量子计算 新型电力系统 决策优化 变分量子算法 量子近似优化算法 混合整数规划 分布式计算
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基于Pochhammer k符号的Lupaş-Beta算子逼近性质
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作者 程文韬 刘玉洁 +1 位作者 杨瑞 华义平 《安庆师范大学学报(自然科学版)》 2024年第1期24-29,共6页
参数型基函数曲线曲面造型的应用与相应算子的结构性质和收敛性质被广泛关注。为此,本文首次利用Beta函数,构造了一种基于Pochhammer k符号的Lupas-Beta含幂参数型算子。同时,利用中心矩研究了该算子的Voronovskaya型渐进公式,根据Ditzi... 参数型基函数曲线曲面造型的应用与相应算子的结构性质和收敛性质被广泛关注。为此,本文首次利用Beta函数,构造了一种基于Pochhammer k符号的Lupas-Beta含幂参数型算子。同时,利用中心矩研究了该算子的Voronovskaya型渐进公式,根据Ditzian-Totik光滑模和Peetre’-K泛函讨论了其全局逼近,并借助函数的分解技巧和区间分割技术等研究了其关于导数为有界变差函数的点态估计。本研究将为该算子在曲线曲面造型中的应用提供关键的理论依据。 展开更多
关键词 Lupas-Beta算子 Pochhammer k符号 全局逼近 有界变差函数
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A NEW ITERATIVE METHOD FOR FINDING COMMON SOLUTIONS OF GENERALIZED EQUILIBRIUM PROBLEM,FIXED POINT PROBLEM OF INFINITE k-STRICT PSEUDO-CONTRACTIVE MAPPINGS,AND QUASI-VARIATIONAL INCLUSION PROBLEM 被引量:5
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作者 刘敏 张石生 《Acta Mathematica Scientia》 SCIE CSCD 2012年第2期499-519,共21页
In this article, we introduce a hybrid iterative scheme for finding a common element of the set of solutions for a generalized equilibrium problems, the set of common fixed point for a family of infinite k-strict pseu... In this article, we introduce a hybrid iterative scheme for finding a common element of the set of solutions for a generalized equilibrium problems, the set of common fixed point for a family of infinite k-strict pseudo-contractive mappings, and the set of solutions of the variational inclusion problem with multi-valued maximal monotone mappings and inverse-strongly monotone mappings in Hilbert space. Under suitable conditions, some strong convergence theorems are proved. Our results extends the recent results in G.L.Acedo and H.K.Xu [2], Zhang, Lee and Chan [8], Wakahashi and Toyoda [9], Takahashi and Takahashi [I0] and S. S. Chang, H. W. Joseph Lee and C. K. Chan [II], S.Takahashi and W.Takahashi [12]. Moreover, the method of proof adopted in this article is different from those of [4] and [12]. 展开更多
关键词 k-strict pseudo-contractive mappings generalized equilibrium problem vis-cosity approximation method variational inclusion problem multi-valuedmaximal monotone mappings s-inverse-strongly monotone mapping
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The sea-air oscillator model of decadal variations in subtropical cells and equatorial Pacific SST 被引量:2
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作者 莫嘉琪 林万涛 林一骅 《Chinese Physics B》 SCIE EI CAS CSCD 2007年第7期1908-1911,共4页
In this paper a time delay equation for sea-air oscillator model is studied. The aim is to create an approximate solving method of nonlinear equation for sea-air oscillator model. Employing the method of variational i... In this paper a time delay equation for sea-air oscillator model is studied. The aim is to create an approximate solving method of nonlinear equation for sea-air oscillator model. Employing the method of variational iteration, it obtains the approximate solution of corresponding equation. This method is an approximate analytic method, which can be often used for analysing other behaviour of the sea surface temperature anomaly of the atmosphere-ocean oscillator model. 展开更多
关键词 nonlinear time delay E1 Nifio-Southern Oscillator variational iteration approximate solution.
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A statistical RCL interconnect delay model taking account of process variations
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作者 朱樟明 万达经 +1 位作者 杨银堂 恩云飞 《Chinese Physics B》 SCIE EI CAS CSCD 2011年第1期659-666,共8页
As the feature size of the CMOS integrated circuit continues to shrink, process variations have become a key factor affecting the interconnect performance. Based on the equivalent Elmore model and the use of the polyn... As the feature size of the CMOS integrated circuit continues to shrink, process variations have become a key factor affecting the interconnect performance. Based on the equivalent Elmore model and the use of the polynomial chaos theory and the Galerkin method, we propose a linear statistical RCL interconnect delay model, taking into account process variations by successive application of the linear approximation method. Based on a variety of nano-CMOS process parameters, HSPICE simulation results show that the maximum error of the proposed model is less than 3.5%. The proposed model is simple, of high precision, and can be used in the analysis and design of nanometer integrated circuit interconnect systems. 展开更多
关键词 process variation interconnect line statistical delay successive linear approximation
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Variational iteration method for solving compressible Euler equations
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作者 赵国忠 蔚喜军 +1 位作者 徐云 朱江 《Chinese Physics B》 SCIE EI CAS CSCD 2010年第7期28-34,共7页
This paper applies the variational iteration method to obtain approximate analytic solutions of compressible Euler equations in gas dynamics. This method is based on the use of Lagrange multiplier for identification o... This paper applies the variational iteration method to obtain approximate analytic solutions of compressible Euler equations in gas dynamics. This method is based on the use of Lagrange multiplier for identification of optimal values of parameters in a functional. Using this method, a rapid convergent sequence is produced which converges to the exact solutions of the problem. Numerical results and comparison with other two numerical solutions verify that this method is very convenient and efficient. 展开更多
关键词 variational iteration method compressible Euler equations approximate analytic solu-tions Lagrange multiplier
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Approximate analytic solutions for a generalized Hirota—Satsuma coupled KdV equation and a coupled mKdV equation
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作者 赵国忠 蔚喜军 +2 位作者 徐云 朱江 吴迪 《Chinese Physics B》 SCIE EI CAS CSCD 2010年第8期46-54,共9页
This paper applies the variational iteration method to obtain approximate analytic solutions of a generalized Hirota-Satsuma coupled Korteweg-de Vries (KdV) equation and a coupled modified Korteweg-de Vries (mKdV)... This paper applies the variational iteration method to obtain approximate analytic solutions of a generalized Hirota-Satsuma coupled Korteweg-de Vries (KdV) equation and a coupled modified Korteweg-de Vries (mKdV) equation. This method provides a sequence Of functions which converges to the exact solution of the problem and is based on the use of Lagrange multiplier for identification of optimal values of parameters in a functional. Some examples are given to demonstrate the reliability and convenience of the method and comparisons are made with the exact solutions. 展开更多
关键词 approximate analytic solutions generalized Hirota-Satsuma coupled KdV equation coupled mKdV equation variational iteration method
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Variational Iteration Method Solutions for Certain Thirteenth Order Ordinary Differential Equations
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作者 Tunde A. Adeosun Olugbenga J. Fenuga +3 位作者 Samuel O. Adelana Abosede M. John Ogunjimi Olalekan Kazeem B. Alao 《Applied Mathematics》 2013年第10期1405-1411,共7页
In this paper, we extend variational iteration method (VIM) to find approximate solutions of linear and nonlinear thirteenth order differential equations in boundary value problems. The method is based on boundary val... In this paper, we extend variational iteration method (VIM) to find approximate solutions of linear and nonlinear thirteenth order differential equations in boundary value problems. The method is based on boundary valued problems. Two numerical examples are presented for the numerical illustration of the method and their results are compared with those considered by [1,2]. The results reveal that VIM is very effective and highly promising in comparison with other numerical methods. 展开更多
关键词 variatIONAL ITERATION Method Boundary Value PROBLEMS Linear and Nonlinear PROBLEMS approximATE Solution
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Analytical Approach to Differential Equations with Piecewise Continuous Arguments via Modified Piecewise Variational Iteration Method
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作者 Qi Wang 《Journal of Applied Mathematics and Physics》 2014年第1期26-31,共6页
In the present article, we apply the modified piecewise variational iteration method to obtain the approximate analytical solutions of the differential equations with piecewise continuous arguments. This technique pro... In the present article, we apply the modified piecewise variational iteration method to obtain the approximate analytical solutions of the differential equations with piecewise continuous arguments. This technique provides a sequence of functions which converges to the exact solution of the problem. Moreover, this method reduces the volume of calculations because it does not need discretization of the variables, linearization or small perturbations. The results seem to show that the method is very reliable and convenient for solving such equations. 展开更多
关键词 Delay Differential EQUATIONS PIECEWISE CONTINUOUS Arguments variatIONAL ITERATION Method approximation
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A Projection and Contraction Method for P-Order Cone Constraint Stochastic Variational Inequality Problem
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作者 Mengdi Zheng Xiaohui Xu Juhe Sun 《Journal of Applied Mathematics and Physics》 2022年第4期1113-1125,共13页
In this paper, we study the p-order cone constraint stochastic variational inequality problem. We first take the sample average approximation method to deal with the expectation and gain an approximation problem, furt... In this paper, we study the p-order cone constraint stochastic variational inequality problem. We first take the sample average approximation method to deal with the expectation and gain an approximation problem, further the rationality is given. When the underlying function is Lipschitz continuous, we acquire a projection and contraction algorithm to solve the approximation problem. In the end, the method is applied to some numerical experiments and the effectiveness of the algorithm is verified. 展开更多
关键词 Stochastic variational Inequality Sample Average approximation Projection and Contraction Method Convergence Analysis Numerical Experiments
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