共查询到20条相似文献，搜索用时 187 毫秒
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对于一个参数进行估计来讲,不仅要考虑估计的精度,还要考虑所得到的估计对于模型拟合的优良程度。通常的损失函数无能为力,而平衡损失函数可以考虑到这两点,本文将在平衡误差损失函数下研究广义Pareto分布参数的Bayes估计问题。在平衡损失函数下导出了参数的Bayes估计并讨论了一类线性形式估计的可容许性和不可容许性。 相似文献
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研究带分数阶时空阻尼项的双曲方程组.利用试验函数方法,通过精细的积分估计得到了该方程组整体解的不存在的充分条件。 相似文献
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本文基于一维函数最优恢复的思想,利用经典的积分离散化方法,以二维dirichlet核为主要逼近工具,对二维周期各向同性函数类进行了重构,得到了上界估计的最佳逼近阶。 相似文献
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许多《数学分析》书中只对含参量x的无穷限非正常积分的一致收敛的柯西准则、一致收敛判别法、性质等进行了分析与论证,面对含参量x的无界函数非正常积分仅给出了积分定义及一致收敛的定义,对一致收敛的柯西准则、一致收敛判别法、性质等均无分析与论证。本文根据无穷限非正常积分与无界函数非正常积分之间的相互转化,得出相应的含参量的无界函数非正常积分一致收敛的柯西准则、一致收敛判别法等。并对含参量x的无界函数非正常积分连续性、可微性和可积性等进行了分析与论证。 相似文献
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在指数分布定数截尾情形下,当先验分布中的超参数部分未知时,在加权平方损失下构造了刻度参数的参数型经验Bayes(PEB)估计,研究了其在均方误差(MSE)准则下相对于一致最小方差无偏估计(UMVUE)的优良性,并获得了PEB估计的大样本性质.当先验分布中的超参数完全未知时,通过数值模拟比较了PEB估计和UMVUE的均方误差,获得了其优良性.最后,通过数值模拟的结果,获得了PEB区间估计的优良性. 相似文献
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利用多维Neville算法实现基于转导思想的函数估计 总被引：1，自引：0，他引：1
根据转导思想的函数估计 ,不用估计函数的模型和参数 ,直接估计函数在给定点的值 ,从根本上区别于传统的函数估计方法 ,但具体的实现算法是一个公开的问题 .讨论使用多维Neville算法实现基于转导思想的函数估计的问题 .利用投影的方法 ,将传统的Neville算法推广到了多维空间 ,在数值计算中引入了核函数的思想 ,从而解决了多维空间的计算问题 ,得到利用多维的Neville算法实现函数估计的方法 .数值试验的结果表明 ,这种方法成功地克服了函数插值的龙格 (Runge)现象 ,有很好的逼近效果 ,并且可以处理多维的函数估计问题 ;同时也给出了对核函数参数进行估计这个难题的一些讨论 .该算法对转导思想的实现提供了一个崭新的途径 . 相似文献
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在多项抽样分布和对数线性模型下,给出了在一般约束条件下,未知参数的最小F散度约束估计,并证明了该估计的渐进正态性。 相似文献
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利用西方经济学的厂商理论和计量经济学的知识探讨了如何对短期生产函数进行有效的估计。以短期生产函数具备的理论特征为标准，分别观察线性估计与非线性估计二者对这些特征的拟合程度，从而优化短期生产函数的估计形式。最后给出了具体的短期生产函数的线性化估计方法，以及专业统计软件的具体实现方式。 相似文献
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Xiaolong Chen Han Zhao Hao Sun Shengchao Zhen Kang Huang 《Journal of The Franklin Institute》2019,356(5):2474-2490
Underactuated mobile robot (UMR) is a typical nonlinear underactuated system with nonholonomic and holonomic constraints. Based on the model of UMR, we propose a novel adaptive robust control to control the UMR and compensate the uncertainties from the view of constraint-following. The uncertainties, which are (possibly fast) time-varying and bounded, include modeling error, initial condition deviation, friction force and other external disturbances. However, the bounds are unknown. To estimate the bounds of the uncertainties, we design an adaptive law which is of leakage type. The uniform boundedness and the uniform ultimate boundedness of the proposed control are verified by Lyapunov method. Furthermore, the effectiveness of the control is shown via numerical simulation of a case. 相似文献
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人脸由于其非刚性明显,受到运动背景变化、形变程度复杂、特征丢失等因素的影响,使得在进行三维动态人脸形变估计时,面临着估计不准,误差较大的问题。为了解决这些问题,提出一种基于特征缺失修复的人脸三维运动形变估计算法,将非刚体人脸运动的形变估计过程中,运用特征补偿方法,补偿由于噪声、形变程度复杂带来的特征丢失缺陷,运用较多的人脸形变特征进行形变分析,准确计算人脸的形变程度。实验结果表明,这种方法得到的解误差较小,效果明显。 相似文献
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The leaderless, prescribed performance consensus problem for groups of agents with antagonistic interactions is addressed for the first time in this paper. We consider agents modeled by pure feedback nonlinear systems with unknown dynamics and an agent communication network described by a signed digraph with a directed spanning tree. A new proportional and integral (PI) variable transformation is proposed that enables the solution of the problem of leaderless bipartite consensus with prescribed performance by recasting it into a regulation problem with prescribed performance, which in turn we solve by a low complexity distributed control law. The algorithm guarantees uniform boundedness of all closed-loop signals and prescribed performance for the bipartite consensus error. Simulations verify the validity of our theoretical analysis. 相似文献
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Walter T. White 《Journal of The Franklin Institute》1948,245(1):25-36
In this paper integral equations are applied for the calculation of the normal modes of vibrating beams. Both exact and approximate methods of solving the integral equation are considered. The Green's function, or kernel, of the integral equation is constructed for both uniform and nonuniform beams. Solutions for the normal modes of a uniform cantilever are given. A nonuniform, naturally-twisted turbine blade is studied in detail and the first and second normal modes are calculated by the integral-equation method. 相似文献
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分部积分法因其对积分具有转化作用，在定积分的估值计算，及积分等式、不等式证明，和二重积分计算等方面具有一些特殊计算作用。此外，分部积分的计算方法可推广至渐次积分。 相似文献
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Regulation of linear systems with both pointwise and distributed input delays by memoryless feedback
《Journal of The Franklin Institute》2019,356(10):5172-5192
This paper is concerned with the stabilization of linear systems with both pointwise and distributed input delays, which can be arbitrarily large yet exactly known. The state vector used in the well-known Artstein transformation is firstly linked with the future state of the system. Pseudo-predictor feedback (PPF) approaches are then established to design memory stabilizing controllers. Necessary and sufficient conditions guaranteeing the stability of the closed-loop system are established in terms of the stability of some integral delay systems. Furthermore, since the PPF still is infinite-dimensional state feedback law and may cause difficulties in their practical implementation, truncated pseudo-predictor feedback (TPPF) approaches are established to design finite dimensional (memoryless) controllers. It is shown that the pointwise and distributed input delays can be compensated properly by the TPPF as long as the open-loop system is polynomially unstable. Finally, two numerical examples, one of which is the spacecraft rendezvous control system, are carried out to support the obtained theoretical results. 相似文献
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《Journal of The Franklin Institute》2022,359(16):8910-8932
An integral predictor-based dynamic surface control scheme is developed with prescribed performance (IPPDSC) for multi-motor driving servo systems in this paper. By employing a novel finite-time performance function and an improved error transformation, the tracking error is limited within a prescribed zone in any preset time without having the overrun and the singularity problem. Furthermore, integral state predictors are designed to update neural network weights to handle high-frequency oscillations under large adaptive gains. Different from the existing approaches, an integral term of prediction error is introduced to eliminate the steady-state error and avoid chattering. In addition, a synchronization controller based on the mean relative coupling structure is proposed to solve the coupling problem between synchronization and tracking. Finally, simulation and experimental results are presented to demonstrate the effectiveness of the designed approach. 相似文献
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Rodrigo P. Lemos Jonas A. Kunzler Diego F. Burgos B. Mário J. de Souza Hugo V.L. e Silva Yroá R. Ferreira Edna L. Flôres Oliver Sander 《Journal of The Franklin Institute》2019,356(9):4949-4969
SEAD method estimates the direction-of-arrival angles on an uniform linear array based on the difference between the two largest singular values, what is called differential spectrum. Although it presented an outstanding performance, the ability to indicate the source positions was not elucidated yet. Inspired by the differential spectrum formulation we derived a total differential spectrum and found out that the matrix norm induced by the vector 2-norm of a modified spatial covariance matrix can be used to estimate the direction-of-arrival of multiple plane waves. Indeed we show that matrix norms are estimators and we propose their use instead of the singular value decomposition in SEAD-based methods. We present a general mathematical expression in order to explicit the operating principles of the proposed methods. Consequently, we were able to explain how the relation between the arriving and the search angles produces the larger peaks on the differential spectrum. To evaluate the important role played by matrix norms, a thousand experiments were carried out. They showed that the proposed approach proved to be as accurate as the previous SEAD-based methods, while providing a significant reduction on runtime. It also outperformed well-established methods like MODEX regarding the estimation error. 相似文献
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In this paper, an adaptive TSK-type CMAC neural control (ATCNC) system via sliding-mode approach is proposed for the chaotic symmetric gyro. The proposed ATCNC system is composed of a neural controller and a supervisory compensator. The neural controller uses a TSK-type CMAC neural network (TCNN) to approximate an ideal controller and the supervisory compensator is designed to guarantee system stable in the Lyapunov stability theorem. The developed TCNN provides more powerful representation than the traditional CMAC neural network. Moreover, all the control parameters of the proposed ATCNC system are evolved in the Lyapunov sense to ensure the system stability with a proportional–integral (PI) type adaptation tuning mechanism. Some simulations are presented to confirm the validity of the proposed ATCNC scheme without the occurrence of chattering phenomena. Further, the proposed PI type adaptation laws can achieve faster convergence of the tracking error than that using integral type adaptation laws in previous published papers. 相似文献