基于MatLab实现的图像边缘检测

图像的边缘提取是灰度不连续的结果,是利用物体和背景在某种图像特性上的差异来实现的,利用Roberts算子、Sobel算子、拉普拉斯高斯算子和Canny算子对智能车赛道图像进行边缘检测,使用MatLab软件实现最后效果的比较,以解决实际问题。     

一种提取随机排列胶囊分离边缘的方法

提取随机排列胶囊图像中分离的、单个的边缘,是胶囊缺陷检测与计数的前提。随机排列的胶囊具有倾斜度不确定和多胶囊粘连的特点。由此,本文先提取胶囊的边缘,再将＂点＂连接与＂线＂连接的胶囊边缘逐步分离,最终完成分离边缘的提取。经过现场实验测试,该方法的边缘识别正确率达到97%。     

Structural reproduction of social networks in computer-mediated communication forums

This study explores the relationship between the structure of an existing social network and the structure of an emergent discussion-board network in an undergraduate university class. Thirty-one students were issued with laptop computers that remained in their possession for the duration of the semester. While using these machines, participants' email log files were collected directly from the University's email servers. The analysis compared structural attributes of actors evident in their social network with the emergent structural properties measured from interactions in a shared discussion board environment. A significant relationship was found between the existing social network structure and the emergent communication patterns, suggesting that existing relationships have a strong influence on subsequent computer-mediated communication. Additional matrices were used to control for gender, major and perceived computer efficacy, none of which had a significant effect.     

Web proxy cache replacement scheme based on back-propagation neural network

Web proxy caches are used to reduce the strain of contemporary web traffic on web servers and network bandwidth providers. In this research, a novel approach to web proxy cache replacement which utilizes neural networks for replacement decisions is developed and analyzed. Neural networks are trained to classify cacheable objects from real world data sets using information known to be important in web proxy caching, such as frequency and recency. Correct classification ratios between 0.85 and 0.88 are obtained both for data used for training and data not used for training. Our approach is compared with Least Recently Used (LRU), Least Frequently Used (LFU) and the optimal case which always rates an object with the number of future requests. Performance is evaluated in simulation for various neural network structures and cache conditions. The final neural networks achieve hit rates that are 86.60% of the optimal in the worst case and 100% of the optimal in the best case. Byte-hit rates are 93.36% of the optimal in the worst case and 99.92% of the optimal in the best case. We examine the input-to-output mappings of individual neural networks and analyze the resulting caching strategy with respect to specific cache conditions.     

Path Hitting in Acyclic Graphs

An instance of the path hitting problem consists of two families of paths, and ℋ, in a common undirected graph, where each path in ℋ is associated with a non-negative cost. We refer to and ℋ as the sets of demand and hitting paths, respectively. When p∈ℋ and share at least one mutual edge, we say that p hits q. The objective is to find a minimum cost subset of ℋ whose members collectively hit those of . In this paper we provide constant factor approximation algorithms for path hitting, confined to instances in which the underlying graph is a tree, a spider, or a star. Although such restricted settings may appear to be very simple, we demonstrate that they still capture some of the most basic covering problems in graphs. Our approach combines several novel ideas: We extend the algorithm of Garg, Vazirani and Yannakakis (Algorithmica, 18:3–20, 1997) for approximate multicuts and multicommodity flows in trees to prove new integrality properties; we present a reduction that involves multiple calls to this extended algorithm; and we introduce a polynomial-time solvable variant of the edge cover problem, which may be of independent interest. An extended abstract of this paper appeared in Proceedings of the 14th Annual European Symposium on Algorithms, 2006. This work is part of D. Segev’s Ph.D. thesis prepared at Tel-Aviv University under the supervision of Prof. Refael Hassin.     

Characterization of surface deformation with the Edge of LightTM technique

The aircraft lap joints are inspected with an enhanced visual inspection technique named “Edge of Light”, which is patented by the NRC Institute for Aerospace Research. This technique is applicable for rapid detection of possible hidden corrosion in lap joints. The surface deformation due to hidden corrosion can be characterized by this optical-based inspection method. In this study, a calibration procedure is developed to quantify the lap joint surface deformation. The effect of surface reflectivity is investigated with the solid film highlighting technique (SolidHi^TM), which helps achieve a uniform reflectivity during the inspection. The efficiency of the technique is demonstrated with the experimental results. This work is supported by NRC-IAR New Initiative Research Funding.     

基于FFMPEG的视频转换系统的模块研究

对互联网视频传播平台的应用现状进行了详细的分析,结合目前视频转换的应用现状,采用CSCW协同工作理论建立的视频转换系统．并对各个层次所采用的技术进行了深入研究,给出了一个基于FFMPEG技术的业务基础架构平台的具体实现。     

基于.NET的用户权限管理设计与实现

讨论基于角色访问控制方式的权限管理思想以及运用该思想进行权限管理系统的设计与实现。     

基于计算缓存方法的分子动力学程序性能优化

分子动力学数值模拟程序在现代高性能计算机上的计算效率往往很低,只能发挥系统峰值性能的几个百分点。本文对并行分子动力学程序PMD3D在联想深腾6800超级计算机上进行性能优化。通过性能分析,我们发现粒子相互作用力计算中相互关联的浮点运算严重影响了处理器的指令级并行效率,为此我们应用计算缓存的方法,将大量不规则的浮点计算进行缓存,达到一定规模后再进行向量化计算。这样使得单机性能在优化后提升4倍多,达到处理器峰值性能5.2GFlops的32.3%。最后,在深腾6800的64个节点的256个CPU上进行了并行性能测试,达到峰值运算性能1.3万亿次的27%。     

蝶类昆虫识别算法的研究与分析

提出利用边缘检测及角点提取来识别蝶类昆虫的方法.通过用四种边缘检测算子对鳞翅目蝴蝶进行边缘检测并作比较分析,从中找出鳞翅目昆虫边缘检测的最佳边缘检测算子,然后对边缘检测后的图像进行了角点提取特征信息,通过实验能够得到蝶类图像的特征,为下一步蝶类识别奠定了基础.