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1.
The convergence criterion of Newton’s method to find the zeros of a map f from a Lie group to its corresponding Lie algebra is established under the assumption that f satisfies the classical Lipschitz condition, and that the radius of convergence ball is also obtained. Furthermore, the radii of the uniqueness balls of the zeros of f are estimated. Owren and Welfert (2000) stated that if the initial point is close sufficiently to a zero of f, then Newton’s method on Lie group converges to the zero; while this paper provides a Kantorovich’s criterion for the convergence of Newton’s method, not requiring the existence of a zero as a priori. 相似文献
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WANG Jin-hua LI Chong 《浙江大学学报(A卷英文版)》2007,8(6):978-986
The convergence criterion of Newton＇s method to find the zeros ofa mapffrom a Lie group to its corresponding Lie algebra is established under the assumption thatfsatisfies the classical Lipschitz condition, and that the radius of convergence ball is also obtained. Furthermore, the radii of the uniqueness balls of the zeros of fare estimated. Owren and Welfert （2000） stated that if the initial point is close sufficiently to a zero off then Newton＇s method on Lie group converges to the zero; while this paper provides a Kantorovich＇s criterion for the convergence of Newton＇s method, not requiring the existence of a zero as a priori. 相似文献
3.
XIA Xu 《重庆大学学报(英文版)》2014,13(2):54-61
The background and purpose, and the current situation of the cost control theory of real estate development project are disscussed in the paper. Problems of cost control for real estate development projects in China are analyzed and summarized. According to the real estate development project cost control problems and related factors, a cost control index system of real estate development enterprise, and a cost control factors index system of real estate projects are constructed respectively. Cost control in the five stages of a real estate development project is introduced and summarized respectively. The five stages include： the investment decision-making, planning and design stage, the bidding phase, project implementation stage, and rental or sale. 相似文献
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In a hybrid system, the subsystems with discrete dynamics play a central role in a hybrid system. In the course of engineering machinery of cluster construction, the discrete control law is hard to obtain because the construction environment is complex and there exist many affecting factors. In this paper, hierarchically intelligent control, expert control and fuzzy control are introduced into the discrete subsystems of engineering machinery of cluster hybrid system, so as to rebuild the hybrid system and make the discrete control law easily and effectively obtained. The structures,reasoning mechanism and arithmetic of intelligent control are replanted to discrete dynamic, continuous process and the interface of the hybrid system. The structures of three types of intelligent hybrid system are presented and the human experiences summarized from engineering machinery of cluster are taken into account. 相似文献
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This paper presents a novel current feedforward control strategy for a three-phase pulse-width modulation (PWM) DC voltage-type converter based on phase and amplitude control (PAC). With right-angle triangle relation of phasors and principle of conservation of energy, a phasor adjustment method and the relevant low-frequency mathematical model of the system are analyzed in detail, both in rectification and regeneration modes for the converter, are discussed. For improving the traditional PAC dynamic performance, variable load current is detected indirectly by the change of the DC voltage, which is fed to the control system as an additional control variable to generate modulation index and phase angle. Also, the algorithm is derived and the system principle is introduced. Experimental results from a 3 kw laboratory device are included to demonstrate the effectiveness of the proposed control strategy. 相似文献
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In virtual environment construction of natural scenes, high realism of the scenes and real time control to the objects in the scene are needed. With a modeling method based on physical properties and a particle system, together with a mipmapping texture technique,good integration between realism and real time control of the natural scenes such as clouds and smoke can be obtained. This paper briefly introduces the basic theory of particle system first, and then describes the construction method of a cloud and smoke particle system. By changing the values of physical properties in the particle system, different shapes and motion status of cloud and smoke result. With a mipmapping technique, real time control and variety of the scenes are improved. Finally an example showing implementation of this method is presented. 相似文献
7.
In this paper, a nonlinear dynamic MIMO model of a 6-DOF underactuated quad rotor rotorcraft is derived based on Newton-Euler formalism. The derivation comprises determining equations of motion of the quad rotor in three dimensions and seeking to approximate the actuation forces through modeling of the aerodynamic coefficients and electric motor dynamics. The derived model is dynamically unstable, so a sequential nonlinear control strategy is implemented for the quad rotor. The control strategy includes exact feedback linearization technique, using the geometric methods of nonlinear control. The performance of the nonlinear control algorithm is evaluated using simulation and the results show the effectiveness of the proposed control strategy for the quad rotor rotorcraft near quasi-stationary flight. 相似文献
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In this paper, a vector regulating principle of the phase and amplitude control （ PAC ） method for three-phase grid-connected inverters is presented. To solve the problem of heavy inrush current and slow dynamic response when system starts up, the starting voltage prediction control and the current feed-forward control are proposed and used, which improve the dynamic performance of the system in the PAC. The experimental results carried out on a three-phase grid-connected inverter proved the validity of the proposed method. 相似文献
9.
This paper proposes a current control scheme for a grid-connected pulse width modulator （PWM） voltage source converter （GC-VSC） under imbalanced and distorted supply voltage conditions. The control scheme is implemented in the positive synchronously rotating reference frame and composed of a single proportional integral （PI） regulator and multi-frequency resonant controllers tuned at the frequencies of 2ω and 6ω, respectively. The experimental results, with the target of eliminating the active power oscillations and current harmonics on a prototype GC-VSC system, validate the feasibility of the proposed current control scheme during supply voltage imbalance and distortion. 相似文献
10.
It’s widely argued that a business environment of budget control and innovation can be antithetical.This essay explores the ways that management accounting and control practices might enable organizations to achieve both control and innovation in the current globalised economy on a basis of the different views in the management control systems(MCSs) and innovation. 相似文献
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P. H. Keskar 《Resonance》2012,17(5):476-486
The ancient Greek mathematician Thales of Miletus devised a method to make large measurements like the heights of pyramids. The straightedge or ruler construction of multiplication can be traced back to this method of Thales. The ruler construction also exists for addition. In this article, we indicate how the comparison between these two constructions leads to Lie theory, a device created by Lie to reduce the multiplicative problems to the additive ones. It is hoped that this enhances the interest in these two themes. 相似文献
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中华龙是史前期一个农耕物侯标志,其生物原型是个体特大的南蛇;古人的龙图腾源于对规律性冬眠后出土蛇类的崇拜,人们据此确定农时。辰溪的"辰"字在古记时十二生肖中表象为龙,境内出土过距今7 800年的龙形图案,且龙舟竞渡等龙崇拜文化源远流长,多学科证据表明辰溪是中华龙文化的重要起源地。 相似文献
13.
Ned Kock Ruth Chatelain-Jardón Jesus Carmona 《Decision Sciences Journal of Innovative Education》2009,7(2):359-375
It seems that surprise events have the potential to turn short-term memories into long-term memories, an unusual phenomenon that may have limited but interesting applications in learning tasks. This surprise-enhanced cognition phenomenon is theoretically modeled based on the notion that many human mental traits have evolved through natural selection; a mathematical analysis building on Price's covariance theorem is employed in this modeling effort. Additionally, the phenomenon is discussed in the context of an online learning task, based on a study involving 186 student participants. A simulated threat was incorporated into a human–computer interface with the goal of increasing the interface's knowledge-transfer effectiveness. The participants were asked to review Web-based learning modules and subsequently take a test on what they had learned. Data from six learning modules in two experimental conditions were contrasted. In the treatment condition, a Web-based screen with a snake in attack position was used to surprise the participants; the snake screen was absent in the control condition. As predicted, the participants in the treatment condition did significantly better in the test for the modules immediately before and after the snake screen than the participants in the control condition. These findings are extrapolated to classroom applications in general. Ethical considerations are also discussed. 相似文献
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柳宗元《捕蛇者说》中的异蛇究竟指什么蛇?有五步蛇、蝮蛇、银环蛇、泛指永州地区的毒蛇之说,也有人认为是虚构的。根据柳宗元的作品与永州的实际分析,异蛇是以五步蛇(蝮蛇)为基础综合加工的,是蒋氏与赋敛发生关系的重要媒介。 相似文献
15.
魏苏宁 《闽西职业大学学报》2008,(1):50-52
图腾崇拜的研究对于了解一个民族的历史、风俗以及人的心理具有重要的意义。在众多对蛇存在着图腾崇拜的民族中,闽越人对蛇的图腾崇拜具有代表性。人们从敬畏到一般崇拜再到图腾崇拜,经历了一系列的变化。闽越人对蛇有着一份特殊的敬意,闽越人崇拜蛇也有着多种多样的表现形式。 相似文献
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朱林生 《常熟理工学院学报》2000,14(2):13-22
引进了ＣＮ李代数、ＣＳ李代数等概念,给出了ＣＮ李代数、ＣＳ李代数与Ｈｅｉｓｅｎｂｅｒｇ代数、对称自对偶李代数的关系,从而首次揭示了完备车代数与共形场论的关系． 相似文献
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主要介绍了Grebner-Shirshov基理论的历史;回顾了自由李代数的合成钻石引进;找到了Lie(X;Ω)的一组线性基底;作为应用,证明了Lie(X;Ω)是带有多元算子的自由李代数. 相似文献