基于Spirent的Web应用性能评测

分析现有在线事务处理(OLTP)类应用评测方法,提出一种基于Spirent的Web应用性能评测方法。采用平均事务响应时间、待测系统资源利用率和每秒事务数作为主要测试指标,将Web服务器和数据库服务器作为一个整体应用,综合评测OLTP类Web应用的软硬件性能,并快速定位Web应用系统的性能瓶颈。测试结果表明,该方法能将Web应用的系统性能提高40多倍,响应时间降低10多倍。     

Winding Roads: Routing edges into bundles

Visualizing graphs containing many nodes and edges efficiently is quite challenging. Drawings of such graphs generally suffer from visual clutter induced by the large amount of edges and their crossings. Consequently it is difficult to read the relationships between nodes and the high‐level edge patterns that may exist in standard node‐link diagram representations. Edge bundling techniques have been proposed to help solve this issue, which rely on high quality edge rerouting. In this paper, we introduce an intuitive edge bundling technique which efficiently reduces edge clutter in graphs drawings. Our method is based on the use of a grid built using the original graph to compute the edge rerouting. In comparison with previously proposed edge bundling methods, our technique improves both the level of clutter reduction and the computation performance. The second contribution of this paper is a GPU‐based rendering method which helps users perceive bundles densities while preserving edge color.     

Efficient Shadow Removal Using Subregion Matching Illumination Transfer

This paper proposes a new shadow removal approach for input single natural image by using subregion matching illumination transfer We first propose an effective and automatic shadow detection algorithm incorporating global successive thresholding scheme and local boundary refinement. Then we present a novel shadow removal algorithm by performing illumination transfer on the matched subregion pairs between the shadow regions and non‐shadow regions, and this method can process complex images with different kinds of shadowed texture regions and illumination conditions. In addition, we develop an efficient shadow boundary processing method by using alpha matte interpolation, which produces seamless transition between the shadow and non‐shadow regions. Experimental results demonstrate the capabilities of our algorithm in both the shadow removal quality and performance.     

3D reconstruction of polyhedral objects from single parallel projections using cubic corner

This paper presents a direct method to recover the geometry of the 3D polyhedron depicted in a single parallel projection. It uses two sets of information, the list of faces in the object, obtained automatically from the drawing, and a user-identified cubic corner, to compute for the coordinates of the vertices in the drawing and thus establish the 3D geometry of the whole polyhedron. The algorithm exploits the topological structure of the polyhedron, implicit in the connectivities between the faces, resulting in a complexity that is linear in the number of faces. The method is extended to objects with no cubic corners as well. The algorithm works well for recovering objects from accurate line drawings, producing accurate 3D objects. A simple extension to the algorithm allows it to handle inaccurate drawings such as sketches, and produce 3D objects that are consistent with our human perception of the drawings.     

How many oblivious robots can explore a line

We consider the problem of exploring an anonymous line by a team of k identical, oblivious, asynchronous deterministic mobile robots that can view the environment but cannot communicate. We completely characterize sizes of teams of robots capable of exploring an n-node line. For k<n, exploration by k robots turns out to be possible, if and only if either k=3, or k?5, or k=4 and n is odd. For all values of k for which exploration is possible, we give an exploration algorithm. For all others, we prove an impossibility result.     

Pathway Preserving Representation of Metabolic Networks

Improvements in biological data acquisition and genomes sequencing now allow to reconstruct entire metabolic networks of many living organisms. The size and complexity of these networks prohibit manual drawing and thereby urge the need of dedicated visualization techniques. An efficient representation of such a network should preserve the topological information of metabolic pathways while respecting biological drawing conventions. These constraints complicate the automatic generation of such visualization as it raises graph drawing issues. In this paper we propose a method to lay out the entire metabolic network while preserving the pathway information as much as possible. That method is flexible as it enables the user to define whether or not node duplication should be performed, to preserve or not the network topology. Our technique combines partitioning, node placement and edge bundling to provide a pseudo‐orthogonal visualization of the metabolic network. To ease pathway information retrieval, we also provide complementary interaction tools that emphasize relevant pathways in the entire metabolic context.     

Goal‐based Caustics

We propose a novel system for designing and manufacturing surfaces that produce desired caustic images when illuminated by a light source. Our system is based on a nonnegative image decomposition using a set of possibly overlapping anisotropic Gaussian kernels. We utilize this decomposition to construct an array of continuous surface patches, each of which focuses light onto one of the Gaussian kernels, either through refraction or reflection. We show how to derive the shape of each continuous patch and arrange them by performing a discrete assignment of patches to kernels in the desired caustic. Our decomposition provides for high fidelity reconstruction of natural images using a small collection of patches. We demonstrate our approach on a wide variety of caustic images by manufacturing physical surfaces with a small number of patches.     

远程生产管理系统在钢铁厂中的应用

远程生产管理系统可以实时采集、查看生产数据。通过此系统,用户可以在线对比、分析生产线数据,判断生产线状况。本系统能够将数据保存下来,为解决问题提供了数据,节约时间,提高工作效率。     

G.723.1高速率语音流的信息隐藏算法

研究流媒体通信中G.723.1高速率语音编码器的分级隐藏方法,分析线谱对频率(LSF)参数的隐藏性能,给出一种基于临界带宽的LSF参数隐藏性能分析方法。在此基础上,结合数位信息法,提出一种G.723.1高速率语音流的信息隐藏算法。实验结果证明了该算法的有效性。     

基于电力线通信的视频监控系统终端设计

为满足家庭和实验室等局部小范围内快速搭建监控系统的需求,设计基于电力线通信(PLC)的视频监控系统终端。该终端系统的PLC模块实现数据在电力线上的传输,控制器模块采用S3C2440处理器芯片,基于Linux操作系统实现视频采集、数据压缩、网络传输、实时显示、存储等功能。实际监控结果表明,该终端成本低、监控网络搭建方便快速、功能扩展能力强。