A simple model for laser drilling

A simple mathematical model of laser drilling is proposed. Assuming axi-symmetry of the process around the axis of the laser beam, a one-dimensional formulation is obtained after cross-sectional averaging. The novelty of the approach relies on the fact that even after dimension reduction, the shape of the hole can still be described. The model is derived, implemented and validated for drilling using lasers with intensities in the GW/cm² range and microsecond pulses.     

Multi-sensor calibration through iterative registration and fusion

In this paper, a new multi-sensor calibration approach, called iterative registration and fusion (IRF), is presented. The key idea of this approach is to use surfaces reconstructed from multiple point clouds to enhance the registration accuracy and robustness. It calibrates the relative position and orientation of the spatial coordinate systems among multiple sensors by iteratively registering the discrete 3D sensor data against an evolving reconstructed B-spline surface, which results from the Kalman filter-based multi-sensor data fusion. Upon each registration, the sensor data gets closer to the surface. Upon fusing the newly registered sensor data with the surface, the updated surface represents the sensor data more accurately. We prove that such an iterative registration and fusion process is guaranteed to converge. We further demonstrate in experiments that the IRF can result in more accurate and more stable calibration than many classical point cloud registration methods.     

计算机绘制曲面型房屋建筑

文中提出了一个主要解决房屋建筑中直纹曲面的计算机造型方法,为此,对这些曲面的几何性质作了分析,并结合流行的三种绘图软件进行试验;然后介绍每一种软件的造型方法,并作分析比较。     

巧用FANUC系统的刀具半径补偿功能

介绍了对刀尖补偿功能的作用、原理和使用方法 ,以车轮轮缘踏面的加工程序为例 ,说明刀具半径补偿功能的具体应用     

Parameterization for reconstruction of 3D freeform objects from laser-scanned data based on a PDE method

Published online: 19 July 2001     

An Efficient Output-Size Sensitive Parallel Algorithm for Hidden-Surface Removal for Terrains

We describe an efficient parallel algorithm for hidden-surface removal for terrain maps. The algorithm runs in O(log ⁴ n) steps on the CREW PRAM model with a work bound of O((n+k) \polylog ( n)) where n and k are the input and output sizes, respectively. In order to achieve the work bound we use a number of techniques, among which our use of persistent data structures is somewhat novel in the context of parallel algorithms. Received July 29, 1998; revised October 5, 1999.     

Experiences with Mathematical Modeling of Electro- Boost in Glass Furnaces

The goal of the latest strategy in glass companies is to decrease the cost of production while maintaining or increasing the glass quality. One of the perspective ways is to install the electric boosting into the existing furnace or to build the new furnace including the electric boosting. This strategy may be surprising as electric energy is generally more expensive than gas or oil （considering the cost per unit energy） but because of efficiency of use （ direct glass - melt heating by Joulean heat） it is inevitably cost effective. The use of the CFD modeling capability for electro - boost designing is presented in this contribution. The Glass Service Glass Furnace Model （ GS - GFM ） is used for investigating the optimal electrode arrangement and phasing, and moreover, for increasing the glass quality during the electro - boost applying.     

应用MODIS资料对城乡地表热通量的估算

为了揭示城市热岛形成机制,基于MODIS资料,结合自动气象站实测的气象资料,利用地表能量参数化方法估算了地表热通量,分析了城乡地表热通量的空间分布及变化特征.结果表明城乡地气热交换差异明显,与相关文献对比证明该方法是可行、有效的.     

Applications of the Conjugate Gradient method in optimal surface parameterizations

This paper concerns the solutions of very large symmetric semipositive definite (singular) linear systems involved in the problem of optimal surface parameterizations using inverse curvature mapping. Two approaches are presented that transform the singular linear systems into two kinds of symmetric positive definite linear systems, so that the famous Conjugate Gradient (CG) method can be used for solving them. Numerical experiments are run on two practical large problems to illustrate that the CG algorithm works very efficiently.