Morse set classification and hierarchical refinement using Conley index

Morse decomposition provides a numerically stable topological representation of vector fields that is crucial for their rigorous interpretation. However, Morse decomposition is not unique, and its granularity directly impacts its computational cost. In this paper, we propose an automatic refinement scheme to construct the Morse Connection Graph (MCG) of a given vector field in a hierarchical fashion. Our framework allows a Morse set to be refined through a local update of the flow combinatorialization graph, as well as the connection regions between Morse sets. The computation is fast because the most expensive computation is concentrated on a small portion of the domain. Furthermore, the present work allows the generation of a topologically consistent hierarchy of MCGs, which cannot be obtained using a global method. The classification of the extracted Morse sets is a crucial step for the construction of the MCG, for which the Poincare′ index is inadequate. We make use of an upper bound for the Conley index, provided by the Betti numbers of an index pair for a translation along the flow, to classify the Morse sets. This upper bound is sufficiently accurate for Morse set classification and provides supportive information for the automatic refinement process. An improved visualization technique for MCG is developed to incorporate the Conley indices. Finally, we apply the proposed techniques to a number of synthetic and realworld simulation data to demonstrate their utility.     

On delay adjustment for dynamic load balancing in distributed virtual environments

Distributed virtual environments (DVEs) are becoming very popular in recent years, due to the rapid growing of applications, such as massive multiplayer online games (MMOGs). As the number of concurrent users increases, scalability becomes one of the major challenges in designing an interactive DVE system. One solution to address this scalability problem is to adopt a multi-server architecture. While some methods focus on the quality of partitioning the load among the servers, others focus on the efficiency of the partitioning process itself. However, all these methods neglect the effect of network delay among the servers on the accuracy of the load balancing solutions. As we show in this paper, the change in the load of the servers due to network delay would affect the performance of the load balancing algorithm. In this work, we conduct a formal analysis of this problem and discuss two efficient delay adjustment schemes to address the problem. Our experimental results show that our proposed schemes can significantly improve the performance of the load balancing algorithm with neglectable computation overhead.     

分段线性动态矩匹配条带去除

由于探测器之间对接收的地物辐射信号的响应特征不同,导致遥感数据含有条带噪声,严重影响了图像质量及后续的定量计算。针对探测器响应函数在图像低值区及高值区呈非线性的特点,在着重分析矩匹配方法的基础上,提出分段线性动态矩匹配条带去除方法。方法设定阈值分割高中低值域统计区间,对探测器响应函数进行分段线性拟合,并对探测器每一分图像动态采用其领域内均值和标准差作为参考值进行条带纠正。应用TM数据第4波段及环境一号卫星高光谱数据进行去条带实验,并定性和定量地比较了该方法与动态矩匹配、傅里叶变换、自动均衡化曲线方法的去条带效果。结果表明该方法能够在保留图像基本信息的前提下,获得最佳的去条带效果,尤其能够提高非均匀地物分布区域内水体的条带去除效果。     

WSUS补丁分发系统在医院内网中的应用

针对与互联网物理隔离的医院内网计算机操作系统无法自动更新的问题,提出应用微软的免费软件WSUS来实现医院内网计算机补丁自动更新。通过对WSUS系统在医院内网中的部署和应用的详细介绍,为有效地避免因系统漏洞引起的病毒爆发和恶意攻击提供了一种思路,在减少维护工作量的同时也提高了医院内网的安全性。     

浅论基于局域网的计算机机房管理维护

随着计算机技术的不断迅猛发展,现在的计算机机房面对大量的计算机设备,传统的管理维护方法已不能胜任,必须充分利用局域网的特性,大量采用新技术,新手段,新软件的辅助,批量的管理维护,提高效率,让计算机设备更好地为人们服务。本文就通过笔者的一些经验来讲述了对于局域网的计算机机房管理维护的一些基本方法。     

中学计算机多媒体技术应用

在新课改的推动下,初中课堂教学改革掀起来热潮,计算机多媒体技术的应用是其中一大亮点。但长期以来,由于很多教师对计算机多媒体技术的初中课堂教学中的作用认识不足,导致应用中出现了一些问题。文章基于初中课堂教学中计算机多媒体技术应用现状的分析基础上来审视计算机多媒体技术的作用,并提出应用策略。     

Correlations between visible light scattering and CO2 laser damage to reflective and antireflective coatings

In this work, 10.6-microm pulsed laser damage studies were performed on reflective and antireflective coatings on Si, Ge, and ZnSe substrates. Single-pulse damage threshold determinations were conducted at two different laser spot sizes. A high-resolution TV system was used to perform visible light scattering studies, the results of which correlated with laser damage at 10.6 microm. Single-pulse damage determinations along with visible light scattering and multipulse damage determinations indicate that coating performance can be improved substantially by reducing the density of scattering centers present on the coatings.     

锻造质量对冷挤压模具寿命的影响

通过改变锻造方法，观察金相组织及模具现场试用，探讨锻造质量对高速钢及基体钢模具寿命的影响，结果表明：控制碳化物不均匀性在三级以内及合理的纤维流线分布，可显著提高引进冷挤压设备上的模具寿命。     

多系列铸铁光电发射光谱标准样品的研制

采用中频炉熔炼，用自行设计的多孔隔离式金属型和独特的补缩和浇注系统及临界激冷工艺进行浇铸，成功地研制出了带有高低标的铸铁系列多元素光电光谱分析标样。对标样的白口化程度、均匀性、呈线性分布及分析精度等进行了检测并得出可行性结论。     

不同增塑体系对丁腈橡胶老化前后及胶管扣压过程性能的影响

本文主要研究了不同增塑体系对丁腈橡胶老化前后物理机械性能的影响,以热油老化后的丁腈橡胶的应力-应变曲线作为材料参数,考察不同增塑体系对丁腈胶管扣压过程中性能变化的影响;硫化特性实验结果表明:使用DOP或DOA作为增塑剂时,硫化胶转矩差值较大,使用液体丁腈或聚硫橡胶作为增塑剂时,转矩差值相对较低,其中使用聚硫橡胶作为增塑剂时,焦烧时间较短;物理机械性能实验结果表明:使用液体丁腈或聚硫橡胶作为增塑剂时,丁腈橡胶硫化胶耐热空气老化性能保持率相对较高,耐热油老化后质量体积变化率相对较低;仿真计算结果表明:使用DOP或DOA作为增塑剂时,静刚度、应变能密度及节点处Mises应力较大,使用液体丁腈或聚硫橡胶作为增塑剂时,静刚度、应变能密度及节点处Mises应力相对较小。