期刊文献+
共找到5篇文章
< 1 >
每页显示 20 50 100
面向数值优化设计的挤出模参数化建模方法 被引量:5
1
作者 刘斌 王敏杰 +1 位作者 刘耀中 赵丹阳 《模具工业》 北大核心 2003年第1期17-19,共3页
采用射线法和比例间隔法相结合的方法 ,利用有限元分析软件ANSYS的参数化设计语言APDL ,建立了挤出口模流道的三维模型。该方法具有适应性强、易于进行设计更改等优点 。
关键词 数值优化设计 挤出模 参数化建模 射线法 挤塑
下载PDF
空间圆柱凸轮轮廓曲面的计算机生成方法 被引量:2
2
作者 赵雪松 高洪 《机械传动》 CSCD 北大核心 2008年第3期59-60,共2页
提出了模拟圆柱凸轮加工过程的圆柱凸轮轮廓曲面的计算机精确生成方法:建立刀具中心空间轨迹方程,保持刀具矩形截面垂直于刀具中心轨迹且沿其切线方向运动,从而在空间圆柱上切割出凸轮轮廓曲面。使用Pro/ENGINEER编程时,则将刀具中心空... 提出了模拟圆柱凸轮加工过程的圆柱凸轮轮廓曲面的计算机精确生成方法:建立刀具中心空间轨迹方程,保持刀具矩形截面垂直于刀具中心轨迹且沿其切线方向运动,从而在空间圆柱上切割出凸轮轮廓曲面。使用Pro/ENGINEER编程时,则将刀具中心空间轨迹方程程序化为基准曲线,应用可变截面扫描工具使矩形截面垂直于基准曲线且沿其切线方向运动,即可在圆柱实体上切割出该圆柱凸轮轮廓曲面。实现了直动从动件圆柱凸轮轮廓曲面设计的可视化和参数化。 展开更多
关键词 圆柱凸轮 刀具中心轨迹方程 可变截面扫描 参数化
下载PDF
二维复杂速度结构中的射线追踪 被引量:2
3
作者 韩果花 李川 +8 位作者 黄明曦 何晓玲 王海燕 杨强 周海滨 王有学 熊彬 张智 薛霆虓 《桂林理工大学学报》 CAS 北大核心 2013年第3期425-429,共5页
针对二维复杂速度结构中的射线追踪,给出模型参数和追踪方法。采用该方法,能够精确地描述复杂的二维地质形体及地质构造的分界面特征,并且能够适用于各种复杂地形的情形;对不同的地层或地质体,根据其速度分布特征,采用局部网格化对其进... 针对二维复杂速度结构中的射线追踪,给出模型参数和追踪方法。采用该方法,能够精确地描述复杂的二维地质形体及地质构造的分界面特征,并且能够适用于各种复杂地形的情形;对不同的地层或地质体,根据其速度分布特征,采用局部网格化对其进行描述,减小了复杂地质结构在描述速度时计算机所需要的内存量,进一步提高了计算速度。本射线追踪方法不仅可以对复杂模型的反射波及回折波进行追踪,而且可以利用"微折射"方法对目标界面的首波进行追踪。 展开更多
关键词 二维复杂速度结构 模型参数化系统 射线追踪
下载PDF
An E-Business Event Stream Mechanism for Improving User Tracing Processes
4
作者 Ayman Mohamed Mostafa Saleh N.Almuayqil Wael Said 《Computers, Materials & Continua》 SCIE EI 2021年第10期767-784,共18页
With the rapid development in business transactions,especially in recent years,it has become necessary to develop different mechanisms to trace business user records in web server log in an efficient way.Online busine... With the rapid development in business transactions,especially in recent years,it has become necessary to develop different mechanisms to trace business user records in web server log in an efficient way.Online business transactions have increased,especially when the user or customer cannot obtain the required service.For example,with the spread of the epidemic Coronavirus(COVID-19)throughout the world,there is a dire need to rely more on online business processes.In order to improve the efficiency and performance of E-business structure,a web server log must be well utilized to have the ability to trace and record infinite user transactions.This paper proposes an event stream mechanism based on formula patterns to enhance business processes and record all user activities in a structured log file.Each user activity is recorded with a set of tracing parameters that can predict the behavior of the user in business operations.The experimental results are conducted by applying clustering-based classification algorithms on two different datasets;namely,Online Shoppers Purchasing Intention and Instacart Market Basket Analysis.The clustering process is used to group related objects into the same cluster,then the classification process measures the predicted classes of clustered objects.The experimental results record provable accuracy in predicting user preferences on both datasets. 展开更多
关键词 Business transactions event stream log file tracing parameters clustering-based classification
下载PDF
3-D seismic tomography for velocity and interface structure of the crust and upper mantle(theoreticalpart)
5
作者 郑需要 张先康 《Acta Seismologica Sinica(English Edition)》 EI CSCD 1998年第5期32-40,共9页
A method of three dimensional (3-D) model parameterization is presented that makes forward and inverse problems become easy. The velocity and interface structure of crust and upper mantle are described by a set of hig... A method of three dimensional (3-D) model parameterization is presented that makes forward and inverse problems become easy. The velocity and interface structure of crust and upper mantle are described by a set of highly smoothed functions. Shooting ray tracing method is chosen to calculate the ray paths for both forward and inverse problems. The partial derivatives of traveltime with respect to parameters of the model grids are calculated analytically while rays are being traced. Because velocity and interface functions have second-order continuous partial derivatives, the geometrical shadow zones at the surface caused by scattering and focusing of ray paths can be prevented. After ray tracing, an equation consisting of matrix and vectors for inverse problem is obtained. We use singular value decomposition method with damped factor to solve the equation. A synthetic data set which consists of several in-line profiles is used to test the methods. The results show that the methods are robust. Compared with the two dimensional method, the 3-D inversion method can give the right position of interfaces and the velocity structure when the crustal model is complicated. 展开更多
关键词 model parameterization ray tracing 3-D inversion crust and upper mantle structure
下载PDF
上一页 1 下一页 到第
使用帮助 返回顶部