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排序方式: 共有955条查询结果,搜索用时 15 毫秒
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With the help of Complex Function Mapping theory, the complicated three-dimensional deformation problems are transferred into two-dimensional problems, and the function of strain ratio field is analyzed in the metal plastic extruding deformation. Taking the strain-hardening effect of metal deformation into account, the relationship between friction behavior and optimized mathematical model is analyzed by the numerical analysis friction energy dissipation function. As a result, the method of lowering the material hardening and decreasing the reduction ratio over multi-procedures can be used to improve the surface quality of metal special-shape extrusion products. 相似文献
64.
This paper addresses the problem of a seamless interface between hydrodynamics and structural analyses. A pressure distribution on a hydro model computed from seakeeping analysis needs to be transferred to a structural model for evaluating structural strength and its integrity. However, due to the differences in the computation and representation methods for both analyses, the load on the hydro model may not be correctly transferred to the structural model, leading to a different load distribution on the structural model and resulting in some unbalanced force and moment components. In this paper, a method is proposed to solve this problem. A pressure distribution on the hydro model is mapped on the structural model through projection, and force and moment imbalances on the structural model are eliminated through optimization of the nodal forces on the structural model. Moreover, a viscous force distribution along the center of each member of the hydro model is transferred to the nodal forces on the structural model based on the minimum distance measure with resolving any force and moment imbalance. Examples are presented to demonstrate the validity of the proposed method. 相似文献
65.
A. Hernández J. Ureña M. Mazo J. J. García A. Jiménez J. A. Jiménez M. C. Pérez F. J. Álvarez C. De Marziani J. P. Dérutin J. Sérot 《Journal of Intelligent and Robotic Systems》2009,55(1):81-106
An advanced adaptive sonar module is described, capable of being configured to different circumstances and distances according
to reflectors found in the environment. Thanks to the sensory distribution, it is possible to identify three basic types of
reflector (planes, edges and corners). Furthermore, a heuristic map of the environment is built. The proposed methods have
been computationally optimized, and implemented in a real-time system based on a Field-Programmable Gate Array (FPGA) and
a Digital Signal Processor (DSP). Results have been obtained in the detection, classification and mapping of obstacles; and
finally testing has been carried out on a commercial vehicle. 相似文献
66.
The aim of the current study was to investigate the effect of oxidation on abrasive wear behaviour of TiC based cermets at temperatures ranging from 20 to 900 °C. Three types of material performance maps were constructed: oxidation rate maps, wear rate maps and maps showing the effect of oxidation on abrasion. Discussion on the performance of different cermet grades is supported by the SEM images combined with EDS and XRD analysis. The results should facilitate the selection of TiC-based cermets providing optimum composition of cermets for high temperature applications. 相似文献
67.
本文就MSS图象的地理位置纠正、分类与成图以及有关问题进行论述。在监督分类过程中,提出并采用了“同类分组法”准则和“相对距离阈值”,以提高分类质量。在地理位置纠正方面,分析了MSS图象的畸变因素,对连续性和非连续性畸变都作了纠正。绘图程序设计中考虑了绘图机的成图特点和效率,以提高图件精度和绘图速度。绘制的杭州西湖地区与大门山地区1∶5万彩色分类图质量好,地理位置正确,自动注记出的高斯—克吕格方里网和地形图上的方里网格完全重合,使遥感分类图象“地图化”。 相似文献
68.
同时定位与地图构建(SLAM)是机器人在未知环境实现自主导航的关键技术,针对目前常用的RGB-D SLAM系统实时性差和精确度低的问题,提出一种新的RGB-D SLAM系统,以进一步提升实时性和精确度。首先,采用ORB算法检测图像特征点,并对提取的特征点采用基于四叉树的均匀化策略进行处理,并结合词袋模型(BoW)进行特征匹配。然后,在系统相机姿态初始值估计阶段,结合PnP和非线性优化方法为后端优化提供一个更接近最优值的初始值;在后端优化中,使用光束法平差(BA)对相机姿态初始值进行迭代优化,从而得到相机姿态的最优值。最后,根据相机姿态和每帧点云地图的对应关系,将所有的点云数据注册到同一个坐标系中,得到场景的稠密点云地图,并对点云地图利用八叉树进行递归式的压缩以得到一种用于机器人导航的三维地图。在TUM RGB-D数据集上,将构建的RGB-D SLAM同RGB-D SLAMv2、ORB-SLAM2系统进行了对比,实验结果表明所构建的RGB-D SLAM系统在实时性和精确度上的综合表现更优。 相似文献
69.
Information sources in the World Wide Web usually offer two different schemes to their users, an Interface Schema which the user can query and a Result Schema which the user can browse. Often the Interface Schema is more restricted than the Result Schema, moreover many sources offer keyword-search interfaces only. Thus query capabilities of such sources are very small and a useful integration into a mediator-based information system using query capabilities is almost impossible. We propose the Query Tunnelling architecture for the wrapping of these restricted web sources. Wrapping of sources by Query Tunneling hides restrictive query interfaces and makes such sources fully queryable based on their result schema. The process of Query Tunneling is divided into two main steps, Query Relaxation to make a higher order query suitable to a restricted interface and Result Restriction in order to filter the results using the original query. 相似文献
70.
吴淑芳 《长春理工大学学报(自然科学版)》2002,25(2):65-68
映射法生成网格一般先分片生成网格,然后不同片上网格拼到一起。此时涉及兼容性问题。本文研究了获得兼容性拼接网格的拼接技术,分三种情况:两片皆为三角形网格、一片为三角形网格,而另一片为四边形网格、两片皆为四边形网格。编制了程序并用数值例子作了验证。 相似文献