Curve Reconstruction with Many Fewer Samples

We consider the problem of sampling points from a collection of smooth curves in the plane, such that the Crust family of proximity‐based reconstruction algorithms can rebuild the curves. Reconstruction requires a dense sampling of local features, i.e., parts of the curve that are close in Euclidean distance but far apart geodesically. We show that ε < 0.47‐sampling is sufficient for our proposed HNN‐Crust variant, improving upon the state‐of‐the‐art requirement of ε < ‐sampling. Thus we may reconstruct curves with many fewer samples. We also present a new sampling scheme that reduces the required density even further than ε < 0.47‐sampling. We achieve this by better controlling the spacing between geodesically consecutive points. Our novel sampling condition is based on the reach, the minimum local feature size along intervals between samples. This is mathematically closer to the reconstruction density requirements, particularly near sharp‐angled features. We prove lower and upper bounds on reach ρ‐sampling density in terms of lfs ε‐sampling and demonstrate that we typically reduce the required number of samples for reconstruction by more than half.     

Fast processing of graph queries on a large database of small and medium-sized data graphs

We propose a new way of indexing a large database of small and medium-sized graphs and processing exact subgraph matching (or subgraph isomorphism) and approximate (full) graph matching queries. Rather than decomposing a graph into smaller units (e.g., paths, trees, graphs) for indexing purposes, we represent each graph in the database by its graph signature, which is essentially a multiset. We construct a disk-based index on all the signatures via bulk loading. During query processing, a query graph is also mapped into its signature, and this signature is searched using the index by performing multiset operations. To improve the precision of exact subgraph matching, we develop a new scheme using the concept of line graphs. Through extensive evaluation on real and synthetic graph datasets, we demonstrate that our approach provides a scalable and efficient disk-based solution for a large database of small and medium-sized graphs.     

一种基于许瓦兹不等式的最优末制导律设计

针对导弹和目标相对运动学关系,利用许瓦兹不等式,提出了一种新的基于制导品质最优的末制导律。在导弹和目标的三维相对运动关系的基础上,忽略三维制导平面的耦合因素,同时考虑二阶的弹体响应环节,建立了导弹制导系统的数学模型。基于在有限时间内零化弹目相对距离和零化弹目视线角速率,以及导弹机动能量最小的优化制导品质的思想,利用许瓦兹不等式推导出一种用解析形式表示的最优末制导律。这种最优制导律通过估算剩余时间,实现对目标的有效拦截。最后通过数字仿真,验证了在脱靶量、弹目视线角速率和机动能量的制导品质方面,所提出的最优制导律要优于一般的比例制导律。     

基于边缘检测和线条特征的新闻字幕探测

新闻视频中的字幕包含有丰富的语义信息,对理解当前的视频内容,具有重要的意义.如何准确的探测出新闻字幕,显得尤为重要.通过对新闻字幕的特点进行分析,提出了一种基于边缘检测和线条特征的新闻字幕探测方法.算法首先对图像进行灰度变换,去除冗余颜色信息,然后进行边缘检测、线条过滤,去除不符合字符特征的线条,最后进行字幕区域探测与合并,提取出字幕.选用不同频道的新闻视频帧对文中算法进行实验,并与其他方法进行比较,结果表明,提出的算法具有较高的探测召回率与探测准确率.     

电镀锌生产线计算机二级管理系统

该文阐述了电镀锌生产线二级管理系统中主要功能模块。该系统能够完整、精确的记录生产管理中的每个细节,包括设备信息、仓库信息、钢卷生产信息和质量信息,最终实现整个生产的无纸化操作。     

对称式八步直线生成算法

分析了直线生成模式与直线斜率之间的关系,提出了一种八步增量算法.该算法一次能画四个像素,结合直线的对称性,在一次循环中可以画八个像素.该算法只用到了整数加法运算、减法运算和左移位运算,大大降低了硬件实现的复杂度,同时有效地提高了速度,易于硬件实现.     

Inverse velocity analysis for line guidance five-axis robots

In this paper, inverse velocity problem for five-axis robots is investigated. The conventional method for a five-axis robot is to pseudo-inverse the 6×5 Jacobian matrix. The solution, primarily based on six freedoms inverse velocity analysis, is just an approximation with a least-square error. A five-axis robot can exactly guide an axis-symmetrical tool in 3-D space. Two exact solutions are provided for five-axis robots. One is based on the screw motion of the tool. The other is based on spherical angles of the tool to derive a 5×5 Jacobian matrix. A new type of singular configuration is discovered and is called the task singularity. The moving path of the line shaped tool is constructed as a ruled surface. Analysis of the angular acceleration shows the surface constructed based on the spherical angle representation has better characteristic. It is concluded that for five-axis robots, the tool position is better represented by five parameters rather than six parameters in order to get better solutions for inverse velocity as well as the motion planning.     

我国大西线“江河连通”调水新格局的设想与评析

利用地理与资源科学的基本原理,在大西线调水线路和"南水北调"工程的启迪下,通过多年野外考察和室内研究,提出"江河连通"调水新格局,试图解决我国水资源开发和水利建设中的重大基础设施问题。"江河连通"调水新格局具有6大明显优势:格局建设灵活机动、全局性比较好、风险小、构建合理及可操作性强、有较好的科学性、后续研究潜力大。针对当前新时代的新要求,我国应加快开展调水线路的核查,深入系统地开展长江与黄河联合调度与调济的可行性研究,把"以电换水"作为今后进一步完善调水的战略目标。     

基于电力线载波技术的病房呼叫系统

本文介绍了以MCS51单片机为核心,基于电力线载波技术的病房呼叫系统,按照特定的电力线载波编码方式进行数据发送。文中给出了该系统的编码方案和硬件组成,分析了各部分的工作原理和软件流程。该系统无需为数据传输专门布线,适合旧病房改造,具有一定的可行性和应用价值。     

森兰SB70G变频器在氧化铝生产线上的应用

本文介绍森兰SB70G变频器在氧化铝生产线上的应用。概述了氧化铝的生产流程和它对变频器的要求,重点叙述了SB70系列变频器在氧化铝生产线上的应用和该系列变频器的接线图及功能参数设置。