共查询到19条相似文献，搜索用时 609 毫秒
1.
负载潮流分析是电力系统规划设计与运作的基础。运用不同方法如牛顿-拉夫逊迭代法、高斯-赛德尔和快速解耦方法,成功地解决了负载潮流测试案例中的互联配电系统问题。对IEEE-30母线网络测试结果表明,牛顿-拉夫逊法能够获得负载潮流问题的最佳解决方案。通过MATLAB编程,得到了降低功率损耗的解决方案和补救措施的实现方法。 相似文献
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成功应用VB软件平台开发了潮流计算软件,该软件充分利用了VB的灵活性、模块性和程序的封装性及易改性;算法是运用牛顿-拉夫逊法,具有较好的收敛性、计算速度快以及占内存小;而且这种设计模型以及编程方式可在稍作修改后用于电力系统分析的其它应用软件,具有很好的扩充性。 相似文献
3.
孙威 《赤峰学院学报(自然科学版)》2014,(20):5-6
在非线性无约束优化上常用的方式有两种,即共轭梯度与拟牛顿,其中共轭梯度方法具备低内存需求以及简单迭代形式,拟牛顿法则是借助于Hesse矩阵正定近似的方式进行牛顿法的近似,因此其收敛速度相对较快,通过大量数值实验证明相对于其他的Broyden族公式而言,BFGS公式数值所具稳定性更好,且将其和非精确搜索方式有机结合应用可获得更为显著的计算效果,因此目前在实践实践计算过程中经常会采用这种方式来进行计算.因传统拟牛顿方程公式中所用梯度信息仅仅只有两步,忽视了函数值信息,因此,有很大部分学者均在拟牛顿方程中添加了函数值,以此希望获得更为显著的计算结果.本文针对求解非线性无约束优化问题的修正BFGS法进行了研究与分析. 相似文献
4.
王小明 《温州职业技术学院学报》2002,2(4):25-30
本用反函数多项式展开法导一组求解高次方程或超越方程的计算公式。这组公式包括了牛顿－拉夫森求根公式以及其它一我具有更高精度的求根公式。采用这些高精度的计算公式解方程，常常无须迭代计算即可一步得到理想的结果。这对于不便于迭代计算的方程的求解有较大的应用意义。 相似文献
5.
杨帆 《甘肃广播电视大学学报》1999,(3):37-43
本采用分析对比的方法,对化学计算中常用到的试差法、牛顿选代法、作图法进行了详解,讨论了三种方法各自的优缺点及实用性,指出牛顿迭代法在复杂计算中的重要性,作图法在化工计算中的实用性,试差法简单不够精确的特点。 相似文献
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单根多楔带驱动附属设备被广泛应用到汽车工业中。考虑多楔带的阻尼特性，及带在带轮上的蠕变造成带段的伸缩对带中张力的影响，建立了n带轮单根多楔带传动系统旋转运动模型，采用Gear反向数值求解法对该模型进行数值求解；对于稳态模型，采用牛顿-拉夫森迭代法对非线性方程进行求解。算例结果表明采用Gear反向数值求解法所得结果，与采用4-5阶龙格-库塔数值解法所得结果相同，但前者计算速度远高于后者。文中建立的多楔带传动系统旋转运动模型和数值求解方法，为带传动系统的研究提供了理论依据，也为非线性方程的求解提供了参考。 相似文献
8.
本文主要介绍了两种修正系统误差的方法,一种是先把每个直接测量的量进行修正,然后代入公式计算;第二种是用误差传递公式计算. 相似文献
9.
廖祖炜 《中国远程教育(综合版)》1983,(2)
微识分学是由牛顿(1642—1727)和莱布尼兹(1646—1716)所创立。当初,这两人创立微积分的思想是不同的。牛顿是用极限的思想,而莱布尼兹是用无限小的思想。按牛顿的思想形成的极限微积分理论——标准分析,在今天已广泛流行;而按莱布尼兹的思想直到三百年后的二十世纪六十年代才由美国数学家逻宾逊用数理逻辑的方法形成第一个精确的无限小微积分理论——非标准分析。二十年来熟悉这一理论的人逐渐多起来,他们发现无限小微积分与极限微积分相比,有着突出的优点:在理论上不仅本身是严密完整的,而且可以使许多数学证明大为简化,在方法上简洁直观。这将有助于新的发现;也便于教学,学好初等代数的人就能接受。 相似文献
10.
插值法是计算数学中应用十分广泛的一种计算求解方法．分析了拉格朗日（Lagrange）插值法、牛顿（Newton）插值法、分段线性插值法和样条插值法四种方法的特征和性质,并对它们各自的特点进行了比较． 相似文献
11.
In this paper, a nonlinear mathematical model for analyzing dynamical response to the large deformation of piles with initial displacements is firstly established with the arc-coordinate, and it is a set of nonlinear integral-differential equations, in which, the Winkeler model is used to simulate the resistance of the soil to the pile. Secondly, a set of new auxiliary functions are introduced. The differential-integral equations are transformed into a set of nonlinear differential equations,and the differential quadrature method (DQM) and the finite difference method (FDM) are applied to discretize the set of nonlinear equations in the spatial and time domains, respectively. Then, the Newton-Raphson method is used to solve the set of discretization algebraic equations at each time step. Finally, numerical examples are presented, and the dynamical responses to the deformation of piles, including configuration, bending moment and shear force, are graphically illuminated. In calculation, two types of initial displacements and dynamical loads are applied, and the effects of parameters on the dynamical responses of piles are analyzed in detail. 相似文献
12.
Logit模型作为一种离散选择模型,被广泛地应用于交通需求预测,其中的交通方式选择是其应用的一个典型。建立logit模型最重要的步骤之一,便是对模型的参数进行标定。logit模型参数估计是极大似然估计,求解参数的算法一般使用NR法(Newton-Raphson)和DGP法(Davidon-Fetcher-Powellmethod),本文尝试采用一种新兴的人工智能算法-蚁群算法,来代替NR法和DGP法对logit模型的参数进行标定。最后结合一实例进行验证,并与NR算法下的结果进行对比,证明蚁群算法解决logit模型参数标定的可行性和合理性。 相似文献
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基于移动最小二乘近似,用无网格法求解考虑材料非线性的混凝土受压柱,在分析中由于混凝土材料的非线性,利用Newton-Raphson迭代法进行求解,编制了相应的分析程序,对混凝土受压柱进行了数值分析。本文分析结果与解析解和有限元解进行比较,吻合较好。 相似文献
14.
运用行列式、分块矩阵运算、正定矩阵的性质与Sherman-Morrison公式证明了正定矩阵的相关结论,结合正定矩阵性质得到了正定线性方程组的一种新的迭代解法和分解,相关的数值实验表明其算法计算量小,至多步比最速下降法快,比共轭梯度法效率高. 相似文献
15.
ZHANG Wei-min MO Yu-long School of Communication Information Engineering Shanghai University Shanghai China 《上海大学学报(英文版)》2000,(Z1)
1 IntroductionIll electrical impedance tomography (EIT) an ~ ofelectrodes (for example, 16, 32 or 64 electrodes) isattached around the Object. Small alternating current areinjected into these electrodes, and the resulting voltagesare measured on the surface. Usually, Two of theelectrodes are used to inject a constallt-aml)litudesinusoidal current, and the others measure the voltagedeveloped on them. An image reconstrUchon algorithm isaPPlied tO the measured data to Produce a cross-sectiona… 相似文献
16.
《教育心理学家》2013,48(4):333-356
Writing learnable instructional text is an art. How can we capture the art and transform it into a science? This paper describes a twinned passages method for capturing text art and demonstrates the method in experiments with 10 United States Army instructional texts. Twinned passages come in pairs: an original and a revised version, with equivalent content. The art has been applied to the revised version to improve its quality. The first step is to verify that the revised version is really better than the original on some meaningful measure; here retention tests were administered after a 24-hr delay. Results showed the revised versions were not forgotten over 24 hrs. For the originals, however, 24% of what had been remembered on an immediate test was forgotten over the 24-hr delay. The next step is to test various hypotheses for the causes of the improvement. Tested here were retrieval, storage, signaling, and readability hypotheses. Tests of other hypotheses are proposed. Several populations of twinned texts are identified that can be used for further research. 相似文献
17.
在用力法解算连续梁时,系数和自由项多,计算量大,绘图多。可运用MATLAB大型数学计算软件分步编制程序来解决这一问题,而在教学过程中可注重概念的分析、推理过程与力学模型的建立。给出了计算和绘图方法。MATLAB的这一应用激发了学生的学习兴趣,改善了结构力学的教学效果。本方法,在结构力学计算中具有普遍的适用性。 相似文献
18.
1 Introduction Electrical i mpedance tomography (EIT) is a non-in-vasive i maging technique with widespread applicationsin medicine and industry[1 ,2].In EITthe electric cur-rent is injected between all possible pairs of adjacentelectrodes , and voltage is measured among all otherelectrodes and a voltage reference electrode .Based onthese boundary measurements ,the internal resistivity(or conductivity) distribution of the body can be esti-mated using the boundary voltage based on various re-… 相似文献
19.
This paper proposes a theoretical method using finite element analysis （FEA） to calculate the plastic collapse loads of pressure vessels under internal pressure, and compares the analytical methods according to three criteria stated in the ASME Boiler Pressure Vessel Code. First, a finite element technique using the arc-length algorithm and the restart analysis is developed to conduct the plastic collapse analysis of vessels, which includes the material and geometry non-linear properties of vessels. Second, as the mechanical properties of vessels are assumed to be elastic-perfectly plastic, the limit load analysis is performed by employing the Newton-Raphson algorithm, while the limit pressure of vessels is obtained by the twice-elastic-slope method and the tangent intersection method respectively to avoid excessive deformation. Finally, the elastic stress analysis under working pressure is conducted and the stress strength of vessels is checked by sorting the stress results. The results are compared with those obtained by experiments and other existing models. This work provides a reference for the selection of the failure criteria and the calculation of the plastic collapse load. 相似文献