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数学学习离不开思维,数学探索需要通过思维来实现,在初中数学教学中逐步渗透数学思想方法,培养思维能力,形成良好的数学思维习惯,数形结合的思想贯穿初中数学教学的始终。数形结合思想的主要内容体现在以下几个方面：a.建立适当的代数模型（主要是方程、不等式或函数模型）;b.建立几何模型（或函数图象）解决有关方程和函数的问题;c.与函数有关的代数、几何综合性问题;d.以图象形式呈现信息的应用性问题。采用数形结合思想解决问题的关键是找准数与形的契合点。如果能将数与形巧妙地结合起来,有效地相互转化,一些看似无法入手的问题就会迎刃而解,产生事半功倍的效果。 相似文献
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<正>函数的奇偶性是一个非常特殊的性质，并在很多实际问题中有着非常广泛的应用.本文主要通过具体例子介绍函数奇偶的这一特性在函数的定积分、曲线积分、重积分计算当中的应用.在高等院校中,高等数学作为各理工科本科生必修的基础课程,在各个领域都有着广泛的应用.而积分计算作为高等数学中的重难点,其重要性是不言而喻的.而函数是高等数学中尤其是微积分的主要研究对象,在学习高等数学的过程中我们不难发现函数具有很多特性,比如单调性、奇偶性、有界性、周期性等,这些特性充分体现了函数的几何美.其中函数奇偶性将数学美体现的淋漓尽致, 相似文献
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本文对超宽带透视雷达系统回波信号处理中的杂波抑制算法进行研究,主要针对近距离或浅层应用中的回波数据杂波抑制问题,提出一种新的基于回波数据能量和数学特征的杂波抑制算法.对实测数据分别用均值法、基于图像处理技术的杂波抑制算法以及基于回波数据能量和数学特征的杂波抑制算法进行处理,结果表明基于回波数据能量和数学特征的杂波抑制算法能够在去除杂波的同时,有效地减少运算的数据量. 相似文献
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针对整体叶轮加工时易变形等特点,选用合理的机床和刀具,在此基础上,利用UG软件,通过几何分析,确定建模流程,最终实现整体叶轮的实体建模和高速加工。 相似文献
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阐述虚拟现实展示设计的概念、特点、表现方式及基本类型,探讨虚拟现实展示设计应该遵循的设计原则和对设计传播的现实意义。通过分析其在商业产品展示、建筑环境展示、文化遗产展示等方面的具体应用,论述其不同的应用价值和意义。并且对三维建模虚拟现实展示与全景虚拟现实展示这两种设计类别进行具体研究论述,阐述其设计实现原理、应用技术及设计内容。 相似文献
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虚拟现实技术可以利用计算机重现现实建筑环境。利用虚拟现实技术进行模拟城市环境、辅助城市规划在国内已引起充分的重视。解决虚拟场景建模主要采用两种方法,一是以传统计算机图形学为基础的几何造型与绘制;二是以现实环境的图像采样为基础建立的基于图像建模与绘制。 相似文献
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目前国际数学界普遍赞同通过开展数学建模活动和在数学教学中推广使用现代化技术来推动数学教育改革.我国普通高中新的数学教学大纲中也明确提出要切实培养学生解决实际问题的能力,要求增强应用数学的意识,能初步运用数学模型解决实际问题.数学建模将各种知识综合应用于解决实际问题中,是培养和提高学生应用所学知识分析问题、解决问题的能力的必备手段之一,是改善学生学习方式的突破口.因此有计划地开展数学建模活动,将有效地培养学生的能力,提高学生的综合素质.
数学建模可以提高学生的学习兴趣,培养学生不怕吃苦、敢于战胜困难的坚强意志,培养自律、团结的优秀品质,培养正确的数学观.具体的调查表明,大部分学生对数学建模比较感兴趣,并不同程度地促进了他们对于数学及其他课程的学习.数学建模能培养学生应用数学进行分析、推理、证明和计算的能力;用数学语言表达实际问题及用普通人能理解的语言表达数学结果的能力;应用计算机及相应数学软件的能力;独立查找文献,自学的能力,组织、协调、管理的能力;创造力、想象力、联想力和洞察力.由此,在高中数学教学中渗透数学建模知识是很有必要的. 相似文献
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<正>数学建模和数学一样,有着悠久的历史。例如欧几里德几何、牛顿万有引力定律、麦克斯伟方程组、门捷列夫周期表、孟德尔遗传定律等都是数学建模的光辉典范。如何培养高中生的数学建模思想,是本文探讨的主 相似文献
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Dezhi Xu Yuchen Dai Chengshun Yang Xinggang Yan 《Journal of The Franklin Institute》2019,356(4):1880-1898
This study focuses on the control of islanded photovoltaic (PV) microgrid and design of a controller for PV system. Because the system operates in islanded mode, the reference voltage and frequency of AC bus are provided by the energy storage system. We mainly designed the controller for PV system in this study, and the control objective is to control the DC bus voltage and output current of PV system. First, a mathematical model of the PV system was set up. In the design of PV system controller, command-filtered backstepping control method was used to construct the virtual controller, and the final controller was designed by using sliding mode control. Considering the uncertainty of circuit parameters in the mathematical model and the unmodeled part of PV system, we have integrated adaptive control in the controller to achieve the on-line identification of component parameters of PV system. Moreover, fuzzy control was used to approximate the unmodeled part of the system. In addition, the projection operator guarantees the boundedness of adaptive estimation. Finally, the control effect of designed controller was verified by MATLAB/Simulink software. By comparing with the control results of proportion-integral (PI) and other controllers, the advanced design of controller was verified. 相似文献
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《Journal of The Franklin Institute》2019,356(17):10260-10276
This paper is concerned with the problem of distributed event-triggered controller design for networked control systems (NCSs) with stochastic cyber-attacks. A decentralized event-triggered scheme is introduced to save the energy consumption and alleviate the transmission load of the network. Each sensor can make its own decision to determine whether the sampled data is delivered to the network or not. By taking two kinds of random cyber-attacks into consideration, a novel mathematical model is constructed for distributed event-triggered NCSs. Sufficient conditions which can guarantee the stability of the control system are obtained by applying Lyapunov stability theory, and the design method of the controller gain is presented in an exact expression. Finally, an example is given to demonstrate the effectiveness of the proposed method. 相似文献
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提出了一种形状可控的B样条曲面补洞算法。此算法在补洞过程中提供了多组可调节的形状参数,分别可以调整中心点的位置,孔洞的凹凸性和孔洞的平整性,从而实现对孔洞形状的调整。对于给定的一组边界曲线及相应的跨界导矢,可以通过调整参数达到对孔洞的不同构造,然后用B样条曲面控制网格表示孔洞,并通过调整控制顶点使得孔洞在各处都满足G1连续。本文的补洞算法提供多组可调控参数,有效的结合了孔洞内部可能的约束条件并可以非常方便的进行调整,从而增加了孔洞修补的灵活性。在放宽对参数的约束时可以实现对孔洞的工艺设计等。 相似文献
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《Journal of The Franklin Institute》2022,359(6):2405-2423
The hydraulic flight motion simulator (HFMS), as a key equipment for hardware-in-the-loop (HWIL) simulation in the field of aerospace, is required to have the ability to accurately simulate the aircraft attitude in the laboratory. However, three model uncertainties including nonlinear friction torque, unbalanced gravity torque and time-varying inertia existing in the outer frame of the HFMS at the same time become a main obstacle to achieving its high-precision position control effect. In this paper, according to identification results of friction torque and gravity torque from experiments, combining with simulation result of time-varying inertia of the outer frame from virtual prototype, a disturbance-observer-based nonlinear robust controller with the model compensation was designed on the basis of the mathematical model. Here, since the model compensation has eliminated the main mismatched uncertainties, dual disturbance observers are only necessary to suppress unmodeled mismatched uncertainties and matched uncertainties. Furthermore, the zero bias of the servo valve was also considered to help controller implementation. Finally, the effectiveness and the practicability of the proposed control method were validated by comparative experiments, which demonstrates that the proposed control method is promising and can be applied in the high-precision position control for the HFMS. 相似文献
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A feedback controller based on an infinite dimensional observer is proposed to solve the synchronous control problem of network wave equations with time-varying and general perturbations at the boundary. An agent in the network as a virtual leader, and all remaining agents need to incrementally track the status of the virtual leader and each agent is controlled by the Neumann-type drive through the boundary. In this paper, by adopting the idea of the active disturbance rejection control (ADRC) technology, the design of the synchronous controller is divided into three parts and has various functions in this paper. Firstly, it compensates the total disturbance asymptotically. Secondly, it ensures the asymptotic convergence between the network state and the virtual leader state to track the virtual leader. Finally, it ensures that the paired states are synchronized. The convergence of infinite dimensional systems and the suitability of closed-loop systems are analyzed and proved. Three network wave equations with disturbance observer feedback control are simulated numerically, and the simulation results show the effectiveness of the proposed method. 相似文献
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提出了一种同步DS-CDMA无线Ad Hoc网络中的有效用户识别方法,采用跨层设计,将MAC层SEEDEX协议中的调度信息用于物理层的帧编码和用户识别. 接收机首先判断是否存在有效用户,如存在则使用当前时隙所有可能发送数据的节点的扩频码来确定有效用户,不存在则直接丢弃该数据帧,从而减少了接收机的能量消耗. 仿真结果表明,该方法同现存的同类算法比较,减小了运算量,节省了接收机能量,改善了接收机错判概率. 相似文献
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提出了用于有界动态随机系统的状态观测器设计方法.首先利用平方根B样条逼近系统的输出概率密度函数来构造残差,同时利用李亚普诺夫函数方法得到观测器增益的自适应调节规律,然后提出了新的对数B样条逼近模型并设计了新的自适应观测器,两个仿真例子表明了方法的有效性. 相似文献
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双凸极变速永磁电机的运行原理及其静态特性的线性分析 总被引：46，自引：0，他引：46
双凸极变速永磁电机是一种全新的机电一体化系统．本文首先简要地介绍了该电机的特点，阐述了电机的基本工作原理和基本控制策略，提出了电机参数的线性数学模型，分析了静态特性 相似文献
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Kabekode V.S. Bhat 《Journal of The Franklin Institute》1981,311(3):171-185
In this paper, we present a consistent theory for the minimization of fuzzy functions given in disjunctive normal form by studying the structure of such functions. An O(N2) time algorithm is given for minimization of a fuzzy function consisting entirely of elementary phrases. The minimal form in this case is shown to be unique (i.e., the minimal form consists of a unique set of phrases). By introducing the notion of standard complex minterms and standard minterms a tabular method is presented and illustrated for the minimization of a disjunctive normal form consisting of entirely complex phrases. The method resembles the well-known Quine-McCluskey tabular procedure for Boolean function minimization. The minimal form in this case may not be unique in general. Finally, the approach is extended for the case of minimization of an arbitrary disjunctive normal form consisting of both elementary as well as complex phrases. 相似文献
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Yong Feng Minghao Zhou Xuemei Zheng Fengling Han Xinghuo Yu 《Journal of The Franklin Institute》2018,355(2):653-674
To control MIMO systems with unmatched uncertainties, two sliding-mode controllers are presented in this paper. Firstly, a terminal sliding-mode controller is presented to force the output of an MIMO system to a region near zero in finite-time. With the analysis on the effect of the unmatched uncertainties, a full-order terminal sliding-mode control is further proposed to force the output of the MIMO system to converge to zero rather than a region. The virtual control is utilized to establish the reference for the part of the system states, which can reject unmatched uncertainties completely. To generate continuous virtual control signals, the proposed full-order terminal sliding-mode controller makes the ideal sliding motion as the full-order dynamics rather than the reduced-order dynamics in traditional sliding-mode control systems. Finally, the simulations on the control of an L-1011 fixed wing aircraft at cruise flight conditions validate the effectiveness of the proposed method. 相似文献