共查询到20条相似文献，搜索用时 220 毫秒
1.
提出了一种基于机器视觉的轨距点定位算法能较好地适应并解决这一问题,该算法在基于机器视觉的基础上获得轨道断面光带图像,并结合LabVIEW软件对图像进行处理得到轨道截面轮廓的测点数据;其次,对轨头测点数据进行曲线拟合得到轨道顶面曲线,应用冒泡算法排序得到轨头测点到顶面曲线切线平移值的距离,选取距离较小的值做二次曲线拟合,求取曲线与切线平移后直线的交点达到对轨距点定位;最终实现对轨距的准确检测。试验结果表明:该算法能够实现轨道轨距点的快速精确定位,捕捉精度可达到1 mm,有效地对轨道轨距进行了检测。 相似文献
2.
《西安文理学院学报》2020,(2)
连续潮流算法通过引入一维校正方程有效地解决了传统潮流在功率极限附近时雅可比矩阵的奇异问题,从而追踪得到负荷不断增加的PV曲线以研究电网系统的静态电压稳定性.基于Matpower程序对连续潮流算法进行改进,通过引入单节点增加负荷以及多节点等步长增加负荷模式,从而追踪得到该模式下的多节点PV曲线以及崩溃电压值.提出了电压崩溃裕度指标和极限功率裕度,用来表征该节点的电压坚强程度.最后以某地区220kV电网为算例进行分析,验证了该方法的有效性. 相似文献
3.
有一一对应关系的 2曲线在对应点处的切线、主法线、副法线中某 2条平行或重合时 ,研究了曲线在该点处的基本向量、曲率、挠率满足的条件 相似文献
4.
有一一对应关系的2曲线在对应点处的切线、主法线、副法线中某2条平行或重合时，研究了曲线在该点处的基本向量、曲率、找率满足的条件。 相似文献
5.
构造了与给定多边形相切的分段三次、五次和六次可调广义Ball曲线,所构造的曲线分别是C1,C2和C3连续,而且对切线多边形是保形的.曲线的所有控制点由切线多边形的顶点直接计算产生.给出了在保持公共连接点处相应连续的条件下内控制点的活动范围.曲线可以在一定范围内做局部修改.计算实例表明文中方法是灵活、方便、有效的. 相似文献
6.
吴光年 《广东教育学院学报》1998,(2)
利用空间曲线的向量参数表示形式ｒ＝ｒ（ｔ）,ａ≤ｔ≤ｂ,讨论了平面曲线Ｔ在奇异点处与其切线Γ的切触阶的奇偶性结果表明,其奇偶性与平面曲线在奇异点处的光滑性有密切联系若平面曲线Γ与切线Ｌ在奇异点有ｎ阶切触,当ｎ为奇数时,曲线是光滑的,当ｎ为偶数时,曲线是不光滑的 相似文献
7.
针对光伏系统最大功率点跟踪(MPPT)方法中的电导增量法,在光伏输出特性曲线I-V曲线最大功率点(MPP)左侧跟踪效率低的缺点,提出了一种改进的方案,即采用I-V曲线和P-V曲线的双轨迹跟踪方法。通过与传统的电导增量法在最大功率点跟踪效率进行仿真比较,发现改进后的方法在不同区间内都能高效地执行跟踪算法,从而提高了系统整体的跟踪效率。 相似文献
8.
杨老记 《邢台职业技术学院学报》2003,20(5):26-28
空间曲线的数学表示形式有多种，而不同的表示形式，求其切线向量的方法也不同。本就工程实际中可能出现的几种空间曲线的数学表示形式．分析其切线向量的求法。 相似文献
9.
王小三 《中学数学研究(江西师大)》2011,(8):22-23
函数图像的切线与该函数导数的几何意义密切相关,同时求曲线的切线方程也是导数的一个基本应用．笔者在教学一元三次曲线的切线问题时,通过独立思考和探究得到了关于一般的一元三次曲线切线的两个结论,现整理成文,供同行鉴赏． 相似文献
10.
为了降低人为设定参数值对支持向量机运行结果准确度的影响,采用智能算法中的人工鱼群算法,搜寻支持向量机相应参数的最优解。由于人工鱼群算法运算在寻优精度和效率方面均有提升空间,故将混沌机制引入人工鱼参数初始化,通过改进固定参数和行为算子得到支持向量机预测模型。使用该模型进行中长期电力需求预测研究,并与其它参数优化算法产生的模型进行均方误差对比。研究结果表明：改进后的模型在拟合均方误差和预测均方误差上都优于未优化的模型,支持向量机在预测精度方面有一定程度的提升。 相似文献
11.
将遗传算法用于电力系统无功优化,并对传统遗传算法的编码方式、遗传操作算子、交叉和变异概率以及迭代终止判据等方面进行了改进,同时使用本文的算法对IEEE6及IEEE14节点系统进行了无功优化计算,结果表明改进后的遗传算法合理可行。 相似文献
12.
1 Introduction Inhomogenetiesintrafficrefertothosefactorsre sultingfromthechangeintrafficflowvolumes ,suchasthechangeinthenumberoflanes ,thedegradationofroads,andthedisturbanceatazebracrossingoratollstation ,etc .Theconsiderationoftheinhomo geneitiesgivesrisetospatiallyvaryingfluxintrafficcontinuummodels ,whichareusuallynon strictlyhy perbolicandhavenotbeenwellunderstoodmathemat ically .Therelatedstudiesinliteraturewerefewandthebehaviorandtheinfluenceoftheseinhomo geneitieswerenotclearenough… 相似文献
13.
The trajectory model of dispersed phase drops and the model of basic flow for drop motion between two inclined parallel plates are derived with the optimized calculation. The analytical results of direct numerical simulation indicate that the basic flow plays an important role in the drop coalescence on liquid-liquid interface. In the stratified two-phase flow field, the smaller droplets are difficult to drain the thin continuous film between the approaching droplets and bulk interfaces and eventually immerse into the trickling film to yield coalescence. They almost attain the velocity of their local surroundings. Moreover, the basic flow exerts a dominant influence on the motion of smaller droplet. The smaller droplets are easily entrained by the basic flow. On the contrary, the larger drop presents advantageous characteristics of coalescence due to its high velocity. The range of 0.3 mm δR≤ 0.75 mm is the advantageous drop coalescence condition since the rapidly varied velocity and its first derivative theoretically cause the forces acting on a drop to become imbalanced. On the other hand, the thin layer of the continuous phase drained from the interval between the drops and trickling film should not be neglected in the calculation of shearing force since it is important for drop rotation. The drop rotation is an indispensable factor in coalescence. 相似文献
14.
An interval estimation procedure for proportion of explained observed variance in latent curve analysis is discussed, which can be used as an aid in the process of choosing between linear and nonlinear models. The method allows obtaining confidence intervals for the R 2 indexes associated with repeatedly followed measures in longitudinal studies. In addition to facilitating evaluation of local model fit, the approach is helpful for purposes of differentiating between plausible models stipulating different patterns of change over time, and in particular in empirical situations characterized by large samples and high statistical power. The procedure is also applicable in cross-sectional studies, as well as with general structural equation models. The method is illustrated using data from a nationally representative study of older adults. 相似文献
15.
The construction of multirate rearrangeable network has long been an interesting problem. Of many results published, all were
achieved on 3-stage Clos network. The monotone routing algorithm proposed by Huet al. (2001) was also first applied to 3-stage Clos network. In this work, we adopt this algorithm and apply it to log
d
(N,m,p) networks. We first analyze the properties of log
d
(N,m,p) networks. Then we use monotone algorithm in log
d
(N,0,p) network. Furthermore we extend the result to construct multirate rearrangeable networks based on log
d
(N,m,p) network (1≤m≤n−1).
Project (No. 10371028) supported by the National Natural Science Foundation of China 相似文献
16.
In freeform surface modelling, developable surfaces have much application value. But, in 3D space, there is not always a regular developable surface which interpolates the given boundary of an arbitrary piecewise smooth closed curve. In this paper, tensor product Bézier surfaces interpolating the closed curves are determined and the resulting surface is a minimum of the functional defined by the L2-integral norm of the Gaussian curvature. The Gaussian curvature of the surfaces is minimized by the method of solving nonlinear optimization problems. An improved approach trust-region form method is proposed. A simple application example is also given. 相似文献
17.
有源电力滤波器（active power filter, APF）补偿电流跟踪控制要求具有较高的稳态精度和较快的动态响应速度。文章将自适应预测滤波算法应用于无差拍控制,实现APF补偿电流精确控制。根据APF时域数学模型,推导滤波系统的无差拍控制离散方程;通过自适应(finite impulse response filter, FIR)预测滤波算法实现基波电流预测,消除控制系统的计算延迟,给无差拍控制提供所需的指令电流预测值。对预测算法进行MATLAB仿真,验证预测算法的稳态精度和动态跟踪快速性;实验室样机验证控制实验结果证明所提出的控制策略有效的,具有一定的实用性。 相似文献
18.
This article reports first-principles band structure calculations forRMn6Sn6 (R=Tb, Dy). The calculation uses the linear muffin-tin orbitals (LMTO) method in the atomic-sphere-approximation (ASA), and
yields results showing that both TbMn6Sn6 and DyMn6Sn6 are ferrimagnetic compounds with antiparallel aligned moments ofR and Mn atoms. In this research the 4f states ofR atoms are treated as localized states, i.e., the hybridization of 4f states with other valence electrons is neglected. The moments of Mn in both compounds were determined to be 2.43 μB and 2.38 μB, respectively. The considerably small additional moments for Mn from the spin-orbit coupling indicates that the spin-orbital
coupling is not dominated for Mn atoms. The total moments of Tb and Dy atoms are 10.28 μB and 11.20 μB. All the calculation findings accorded well with experimental results.
Project supported by the Scientific Research Foundation for the Returned Overseas Chinese Scholars, State Education Ministry
of China. 相似文献
19.
数据稀疏是协同过滤预测精度的一个重要影响因素。Slope One算法使用简单的线性回归模型解决该问题,但它只使用评分数据做计算,未考虑相似性。提出一种基于用户习惯偏好相似度的Slope One算法（UPS Slope One）。UPS Slope One首先基于用户习惯偏好聚类,得到三组不同偏好的用户,然后分别计算各组评分偏差,计算时将用户习惯偏好相似度融入其中,最后使用线性回归模型预测评分。在MovieLens数据集上的实验表明,该算法可得到更高的推荐质量、预测准确性和稳定性。 相似文献
20.
张扬永 《福建工程学院学报》2021,(6):560-567
针对现有的智能交通系统预测方法,基于道路交通的关键参数车流量预测,提出了一种基于深度学习的时间序列交通流预测方法,进一步提升道路交通车流量预测准确率。在对道路交通数据集进行清洗后,使用时间序列和神经网络的结合算法TS-NN 进行车流量预测,实验表明,在城市路段的预测中,TS-NN 相对时间序列模型ARIMA、神经网络模型LSTM 准确率分别提升了1.62%和2.13%?在高速公路数据集上测试上,TS-NN 有更加明显的改进,相对ARIMA、LSTM 分别提升了20.87%和3.53%,在一定程度上,TS-NN 算法确实有助于改进智能交通系统核心算法。 相似文献