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基于VMD-SSA-K-means-iForest的重力坝监测数据异常模式混合识别算法研究
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作者 李铁 李涵曼 +2 位作者 王福生 徐量 郭瑞 《水电能源科学》 北大核心 2026年第1期182-187,共6页
重力坝监测数据的异常识别对大坝安全评估具有重要意义,针对现有方法在模式辨识和特征提取方面的局限性,提出一种基于VMD-SSA-KMeans-iForest的重力坝监测数据异常值混合识别方法,该方法通过引入变分模态分解(VMD)优化SSA分解过程,显著... 重力坝监测数据的异常识别对大坝安全评估具有重要意义,针对现有方法在模式辨识和特征提取方面的局限性,提出一种基于VMD-SSA-KMeans-iForest的重力坝监测数据异常值混合识别方法,该方法通过引入变分模态分解(VMD)优化SSA分解过程,显著提升了特征提取的精度和鲁棒性。在此基础上,构建了基于K-means聚类与孤立森林(iForest)协同的异常识别框架,并将该方法应用于W重力坝异常数据识别中。结果表明,所提方法的异常识别准确率提升了2.5%,同时有效区分了结构损伤与仪器故障引起的异常模式,为重力坝安全评估提供了更可靠的技术支持。 展开更多
关键词 重力坝 奇异谱分析 变分模态分解 K-meanS聚类 孤立森林 异常模式识别
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A Number Theoretic Function and Its Mean Value Computation 被引量:1
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作者 李海龙 杨倩丽 《Chinese Quarterly Journal of Mathematics》 CSCD 2002年第3期53-56,共4页
Let p be a prime, n be any positiv e integer, α(n,p) denotes the power of p in the factorization of n! . In this paper, we give an exact computing formula of the mean value ∑ n<Nα(n,p).
关键词 number theoretic function mean value computing formula
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基于k-means算法的聚类个数确定方法改进 被引量:5
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作者 王丙参 王国长 魏艳华 《统计与决策》 北大核心 2025年第7期59-64,共6页
文章基于k-means算法探讨了最优聚类个数k*的确定方法:第一类是统计量方法;第二类是聚类算法不稳定性方法,即基于两次聚类结果间的距离,利用交叉验证、随机抽样取交集、自助法来构建聚类算法估计不稳定性指标,并根据投票、最小化均值方... 文章基于k-means算法探讨了最优聚类个数k*的确定方法:第一类是统计量方法;第二类是聚类算法不稳定性方法,即基于两次聚类结果间的距离,利用交叉验证、随机抽样取交集、自助法来构建聚类算法估计不稳定性指标,并根据投票、最小化均值方法确定k^(*)。数值模拟结果显示:在给定k^(*)的情况下,聚类结果与标签的距离或相似度可作为评价聚类结果的指标,为聚类算法评价提供了新的借鉴;基于k-means算法确定k^(*)的前提是数据集根据欧氏距离可明显分为几簇,相对而言,聚类算法不稳定性方法优于统计量方法;对于不稳定性指标,交叉验证估计方法与随机抽样取交集估计方法对抽样个数稳健,抽样个数依次建议略少于样本容量的1/3、80%;自助抽样估计方法由于利用了全部样本,因此效率更高;4种不稳定性指标没有显著差异,投票与最小化均值方法也没有显著差异。 展开更多
关键词 K-meanS算法 聚类个数 统计量 不稳定性
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THE SCHUR CONVEXITY OF GINI MEAN VALUES IN THE SENSE OF HARMONIC MEAN 被引量:5
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作者 夏卫锋 褚玉明 《Acta Mathematica Scientia》 SCIE CSCD 2011年第3期1103-1112,共10页
We prove that the Gini mean values S(a,b; x,y) are Schur harmonic convex with respect to (x,y)∈(0,∞)×(0,∞) if and only if (a, b) ∈{(a, b):a≥0,a ≥ b,a+b+1≥0}∪{(a,b):b≥0,b≥a,a+b+1≥0} ... We prove that the Gini mean values S(a,b; x,y) are Schur harmonic convex with respect to (x,y)∈(0,∞)×(0,∞) if and only if (a, b) ∈{(a, b):a≥0,a ≥ b,a+b+1≥0}∪{(a,b):b≥0,b≥a,a+b+1≥0} and Schur harmonic concave with respect to (x,y) ∈ (0,∞)×(0,∞) if and only if (a,b)∈{(a,b):a≤0,b≤0,a|b|1≤0}. 展开更多
关键词 Gini mean values Schur convex Schur harmonic convex
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The Asymptotic Property of Generalized Taylor Remainder "Mean Value Point" 被引量:4
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作者 RENLi-shun ZHANGCai-yu 《Chinese Quarterly Journal of Mathematics》 CSCD 2004年第3期314-318,共5页
This paper discussed asymptotic property of Taylor remainder 'mean value point' in normed Linear space. The asymptotic progerty of 'mean value point' is solved when f(n+i)(x0)h(n+i) = 0(i = 1, 2,..., p... This paper discussed asymptotic property of Taylor remainder 'mean value point' in normed Linear space. The asymptotic progerty of 'mean value point' is solved when f(n+i)(x0)h(n+i) = 0(i = 1, 2,..., p - 1) and f(n+p)(x0)h(h+p) don't exist. Meanwhile, achieve more general asymptotic estimation formula. Make many former results are just because of special case of the pager. 展开更多
关键词 functional F-derivative Gα-derivative mean value point assymptotic property
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Mesh Deformation Method Based on Mean Value Coordinates Interpolation 被引量:1
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作者 Shuli Sun Shuming Lv +1 位作者 Yuan Yuan Mingwu Yuan 《Acta Mechanica Solida Sinica》 SCIE EI CSCD 2016年第1期1-12,共12页
Mesh deformation technique is widely used in many application fields, and has re- ceived a lot of attentions in recent years. This paper focuses on the methodology and algorithm of algebraic type mesh deformation for ... Mesh deformation technique is widely used in many application fields, and has re- ceived a lot of attentions in recent years. This paper focuses on the methodology and algorithm of algebraic type mesh deformation for unstructured mesh in numerical discretization. To preserve mesh quality effectively, an algebraic approach for two and three dimensional unstructured mesh is developed based on mean value coordinates interpolation combined with node visibility analysis. The proposed approach firstly performs node visibility analysis to find out the visible boundary for each grid point to be moved, then evaluates the mean value coordinates of each grid point with respect to all vertices on its visible boundary. Thus the displacements of grid points can be calculated by interpolating the boundary movement by the mean value coordinates. Compared with other methods, the proposed method has good deformation capability and predictable com- putational cost, with no need to select parameters or functions. Applications of mesh deformation in different fields are presented to demonstrate the effectiveness of the proposed approach. The results of numerical experiments exhibit not only superior deformation capability of the method in traditional applications of fluid dynamic grid, but also great potential in modeling for large deformation analysis and inverse design problems. 展开更多
关键词 unstructured mesh mesh deformation mean value coordinates (MVC) visibilityanalysis domain partition
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Some Hybrid Mean Values of a New Number Theoretic Function 被引量:1
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作者 REN Gang-lian 《Chinese Quarterly Journal of Mathematics》 CSCD 北大核心 2008年第3期325-329,共5页
Let p and q be two distinct primes, epq(n) denotes the largest exponent of power pq which divides n. In this paper, we study the mean value properties of function epq(n), and give some hybrid mean value formulas f... Let p and q be two distinct primes, epq(n) denotes the largest exponent of power pq which divides n. In this paper, we study the mean value properties of function epq(n), and give some hybrid mean value formulas for epq(n) and Dirichlet divisor function d(n). Key words: largest exponent; asymptotic formula; hybrid mean value; Dirichlet divisor function d(n) 展开更多
关键词 largest exponent asymptotic formula hybrid mean value Dirichlet divisor function d(n)
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基于改进K-means算法的室内可见光通信O-OFDM系统信道均衡技术 被引量:1
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作者 贾科军 连江龙 +1 位作者 张常瑞 蔺莹 《电讯技术》 北大核心 2025年第1期96-102,共7页
在室内可见光通信中符号间干扰和噪声会严重影响系统性能,K均值(K-means)均衡方法可以抑制光无线信道的影响,但其复杂度较高,且在聚类边界处易出现误判。提出了改进聚类中心点的K-means(Improved Center K-means,IC-Kmeans)算法,通过随... 在室内可见光通信中符号间干扰和噪声会严重影响系统性能,K均值(K-means)均衡方法可以抑制光无线信道的影响,但其复杂度较高,且在聚类边界处易出现误判。提出了改进聚类中心点的K-means(Improved Center K-means,IC-Kmeans)算法,通过随机生成足够长的训练序列,然后将训练序列每一簇的均值作为K-means聚类中心,避免了传统K-means反复迭代寻找聚类中心。进一步,提出了基于神经网络的IC-Kmeans(Neural Network Based IC-Kmeans,NNIC-Kmeans)算法,使用反向传播神经网络将接收端二维数据映射至三维空间,以增加不同簇之间混合数据的距离,提高了分类准确性。蒙特卡罗误码率仿真表明,IC-Kmeans均衡和传统K-means算法的误码率性能相当,但可以显著降低复杂度,特别是在信噪比较小时。同时,在室内多径信道模型下,与IC-Kmeans和传统Kmeans均衡相比,NNIC-Kmeans均衡的光正交频分复用系统误码率性能最好。 展开更多
关键词 可见光通信 光正交频分复用 多径信道 信道均衡 K-means算法 反向传播神经网络
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Prognostic value of preoperative mean corpuscular volume in esophageal squamous cell carcinoma 被引量:2
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作者 Yu-Zhen Zheng Shu-Qin Dai +5 位作者 Wei Li Xun Cao Yong Li Lan-Jun Zhang Jian-Hua Fu JunYe Wang 《World Journal of Gastroenterology》 SCIE CAS 2013年第18期2811-2817,共7页
AIM: To evaluate whether preoperative mean corpuscular volume (MCV) is a prognostic indicator in patients with resectable esophageal squamous cell carcinoma (ESCC). METHODS: A total of 298 consecutive, prospectively e... AIM: To evaluate whether preoperative mean corpuscular volume (MCV) is a prognostic indicator in patients with resectable esophageal squamous cell carcinoma (ESCC). METHODS: A total of 298 consecutive, prospectively enrolled patients with histologically diagnosed ESCC who underwent surgery with curative intent from 2001 to 2011 were retrospectively evaluated. Patients were excluded if they had previous malignant disease, distant metastasis at the time of primary treatment, a history of neoadjuvant treatment, had undergone nonradical resection, or had died of a non-tumor-associated cause. Survival status was verified in September 2011. Pathological staging was performed based on the 2010 American Joint Committee on Cancer criteria. Preoperative MCV was obtained from blood counts performed routinely within 7 d prior to surgery. Receiver operating characteristic (ROC) curve analysis was used to determine a cutoff for preoperative MCV. RESULTS: The 298 patients consisted of 230 males and 68 females, with a median follow-up of 30.1 mo. ROC analysis showed an optimal cutoff for preoperative MCV of 95.6 fl. Fifty-nine patients (19.8%) had high (> 95.6 fl) and 239 (80.2%) had low (≤ 95.6 fl) preoperative MCV. Preoperative MCV was significantly associated with gender (P=0.003), body mass index (P=0.017), and preoperative red blood cell count (P<0.001). The predicted 1-, 3and 5-year overall survival (OS) rates were 72%, 60% and 52%, respectively. Median OS was significantly longer in patients with low than with high preoperative MCV (27.5 mo vs 19.4 mo, P<0.001). Multivariate analysis showed that advanced pT (P=0.018) and pN (P<0.001) stages, upper thoracic location (P=0.010), lower preoperative albumin concentration (P=0.002), and high preoperative MCV (P=0.001) were negative prognostic factors in patients with ESCC. Preoperative MCV also stratified OS in patients with T3, N1-N3, G2-G3 and stage Ⅲ tumors. CONCLUSION: Preoperative MCV is a prognostic factor in patients with ESCC. 展开更多
关键词 PREOPERATIVE MARKERS mean corpuscular volume PROGNOSIS Resectable ESOPHAGEAL NEOPLASMS
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基于AE并融合GMM与K-means的无监督颤振监测研究
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作者 王丹 张凤南 +1 位作者 马岩尉 刘博 《工具技术》 北大核心 2025年第2期139-145,共7页
金属切削过程中颤振的监测方法大致可分为颤振特征提取和聚类分析,其中提取方法有一定的局限性。本文提出一种基于大量未标记动态信号的无监督铣削颤振监测方法,该方法不依赖加工参数和环境,不需要标签,稳定性强,切削力信号来自多次铣... 金属切削过程中颤振的监测方法大致可分为颤振特征提取和聚类分析,其中提取方法有一定的局限性。本文提出一种基于大量未标记动态信号的无监督铣削颤振监测方法,该方法不依赖加工参数和环境,不需要标签,稳定性强,切削力信号来自多次铣削实验。该方法基于自动编码将信号的每一段压缩成二维,使用基于高斯混合模型和K-means合并的混合聚类方法对压缩信号进行聚类。所提出的方法在所有6个典型的无监督评价指标中都优于高斯混合模型和K-means算法。 展开更多
关键词 颤振监测 高斯混合模型 K-meanS 无监督聚类 自动编码器
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Mean Square Heun’s Method Convergent for Solving Random Differential Initial Value Problems of First Order 被引量:2
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作者 M. A. Sohaly 《American Journal of Computational Mathematics》 2014年第5期474-481,共8页
This paper deals with the construction of Heun’s method of random initial value problems. Sufficient conditions for their mean square convergence are established. Main statistical properties of the approximations pro... This paper deals with the construction of Heun’s method of random initial value problems. Sufficient conditions for their mean square convergence are established. Main statistical properties of the approximations processes are computed in several illustrative examples. 展开更多
关键词 Stochastic Partial DIFFERENTIAL Equations mean SQUARE SENSE Second Order RANDOM Variable
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On the Mean Value of High-Powers of a Special Character Sum Modulo a Prime
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作者 Xiaodan Yuan Wenpeng Zhang 《Computer Modeling in Engineering & Sciences》 SCIE EI 2023年第7期943-953,共11页
In this paper,we use the elementary methods,the properties of Dirichlet character sums and the classical Gauss sums to study the estimation of the mean value of high-powers for a special character sum modulo a prime,a... In this paper,we use the elementary methods,the properties of Dirichlet character sums and the classical Gauss sums to study the estimation of the mean value of high-powers for a special character sum modulo a prime,and derive an exact computational formula.It can be conveniently programmed by the“Mathematica”software,by which we can get the exact results easily. 展开更多
关键词 Quadratic character the classical gauss sums the mean value of high-power computational formula
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THE MEAN VALUE THEOREM AND CONVERSE THEOREM OF ONE CLASS THE FOURTH-ORDER PARTIAL DIFFERENTIAL EQUATIONS
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作者 同小军 同登科 陈绵云 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 2001年第6期717-723,共7页
For the formal presentation about the definite problems of ultra-hyperbolic equations, the famous Asgeirsson mean value theorem has answered that Cauchy problems are ill-posed to ultra-hyperbolic partial differential ... For the formal presentation about the definite problems of ultra-hyperbolic equations, the famous Asgeirsson mean value theorem has answered that Cauchy problems are ill-posed to ultra-hyperbolic partial differential equations of the second-order. So it is important to develop Asgeirsson mean value theorem. The mean value of solution for the higher order equation hay been discussed primarily and has no exact result at present. The mean value theorem for the higher order equation can be deduced and satisfied generalized biaxial symmetry potential equation by using the result of Asgeirsson mean value theorem and the properties of derivation and integration. Moreover, the mean value formula can be obtained by using the regular solutions of potential equation and the special properties of Jacobi polynomials. Its converse theorem is also proved. The obtained results make it possible to discuss on continuation of the solutions and well posed problem. 展开更多
关键词 Asgeirsson mean value theorem generalized biaxial symmetry potential equation Jacobi polynomials
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基于启发式交叉策略优化的K-Means聚类算法
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作者 张立娜 张兴瑞 +2 位作者 马丽 于合龙 宋欣怡 《吉林大学学报(理学版)》 北大核心 2025年第6期1663-1672,共10页
针对传统K-Means算法对初始质心敏感、易陷入局部最优以及未能充分挖掘聚类结果潜在语义特征的问题,提出一种基于启发式交叉策略优化的K-Means聚类算法.首先,该算法通过密度驱动的启发式交叉初始化策略,筛选高密度区域的代表性父代点,... 针对传统K-Means算法对初始质心敏感、易陷入局部最优以及未能充分挖掘聚类结果潜在语义特征的问题,提出一种基于启发式交叉策略优化的K-Means聚类算法.首先,该算法通过密度驱动的启发式交叉初始化策略,筛选高密度区域的代表性父代点,并引入交叉系数动态生成多样性初始质心,以降低随机初始化导致的聚类结果波动性;其次,在聚类迭代过程中,结合父代点信息与簇内均值更新规则,通过交叉操作动态调整质心位置,解决了传统算法因局部最优导致的簇间重叠问题;最后,将优化后的聚类结果输入多层感知机,利用其非线性映射能力挖掘潜在特征,实现了聚类结果与深层语义特征的深度融合.实验结果表明,该算法的轮廓系数、Davies-Bouldin指数和调整Rand指数分别达0.634,1.398,0.621,显著优于其他改进算法,有效提升了算法的聚类准确性、稳定性和可解释性. 展开更多
关键词 启发式交叉策略 K-meanS聚类算法 多层感知机 特征融合
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On the Lucas Base and Computation of Counting Function Mean Value
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作者 LIHai-long LIUHua-ke 《Chinese Quarterly Journal of Mathematics》 CSCD 2004年第1期84-89,共6页
In this paper, we introduce a new counting function a(m) related to the Lucas number, then use conjecture and induction methods to give an exact formula Ar(N)=α(n), (r=1,2,3) and prove them.
关键词 Lucas sequence Fibonacci sequence mean value counting fuction
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高效的云外包隐私保护K-means聚类研究
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作者 曹来成 靳娜维 +1 位作者 冯涛 郭显 《华中科技大学学报(自然科学版)》 北大核心 2025年第5期143-149,共7页
为提高云外包隐私保护K-means算法的聚类效率和计算来自多方用户的密文数据,提出一种可以高效计算多方密文的云外包隐私保护K-means聚类方案.首先,基于稀疏约束的非负矩阵分解算法实现了高维数据的低维表示,从而有效提高了K-means聚类... 为提高云外包隐私保护K-means算法的聚类效率和计算来自多方用户的密文数据,提出一种可以高效计算多方密文的云外包隐私保护K-means聚类方案.首先,基于稀疏约束的非负矩阵分解算法实现了高维数据的低维表示,从而有效提高了K-means聚类算法在高维数据下的聚类效果;然后,采用基于共用密钥的多密钥全同态加密技术解决了多方密文在云服务器进行K-means聚类时存在同态运算复杂的问题,在此过程中通过构建四个安全的基础协议使隐私信息得到了保护;最后,使用三角不等式定理实现K-means聚类算法的剪枝优化,减少了聚类中存在的冗余距离计算,提高了聚类效率.实验结果表明:所提方案当处理高维数据时有着较高的聚类效率,且准确率接近于明文数据下的聚类. 展开更多
关键词 K-meanS算法 多密钥全同态加密 云外包 隐私保护 高维数据
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On the Mean Value of the Infinite Order Legendre Series
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作者 王安斌 《Chinese Quarterly Journal of Mathematics》 CSCD 1996年第4期6-12, ,共7页
In this paper, we studies the relations between the mean value and the maximun norm of the infinite order entire functions which defined by legendre series. We obtained that if f(z) is an infinite order entire functio... In this paper, we studies the relations between the mean value and the maximun norm of the infinite order entire functions which defined by legendre series. We obtained that if f(z) is an infinite order entire function with a positive exponenatial lower order. then loaM (α) ~logMδ(α) ~ logMδ(α) (α→+∞). 展开更多
关键词 cntire function mean value order
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A New Compound Function and Its Mean Value
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作者 MA Jin-ping GE Jian 《Chinese Quarterly Journal of Mathematics》 CSCD 2010年第2期312-316,共5页
The main purpose of this paper is using the analytic method to study the mean value properties of the arithmetical functions δk((m, n)), δk([m,n]/m),and give several interesting asymptotic formulae for them.
关键词 arithmetic function mean value asymptotic formula
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Hybrid Mean Value of the Hyper Cochrane Sums
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作者 ZHANG TIAN-PING 《Communications in Mathematical Research》 CSCD 2009年第4期329-339,共11页
The main purpose of this paper is to use the analytic methods to study the hybrid mean value involving the hyper Cochrane sums, and give several sharp asymptotic formulae.
关键词 hyper Cochrane sum hyper-Kloosterman sum hybrid mean value
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A New Proof of the Stronger Second Mean Value Theorem for Integrals
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作者 Peng ZHENG Xiquan SHI 《Journal of Mathematical Research with Applications》 CSCD 2021年第3期265-269,共5页
R.Witula et al obtained a stronger version of the second mean value theorem for integral with some restrictions.In this paper,the stronger version theorem is proved without any restriction.The result is first restrict... R.Witula et al obtained a stronger version of the second mean value theorem for integral with some restrictions.In this paper,the stronger version theorem is proved without any restriction.The result is first restricted to the Riemann integrable functions and can be easily generalized to L~p integrable functions by using the well-known result that continuous functions are dense in the Banach space L~p[a,b]for any p≥1. 展开更多
关键词 second mean value theorem for integrals Riemann integrable Lebesgue integrable
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