Escrow-free encryption supporting cryptographic workflow

Since Boneh and Franklin published their seminal paper on identity based encryption (IBE) using the Weil pairing, there has been a great deal of interest in cryptographic primitives based on elliptic-curve pairings. One particularly interesting application has been to control access to data, via possibly complex policies. In this paper we continue the research in this vein. We present an encryption scheme such that the receiver of an encrypted message can only decrypt if it satisfies a particular policy chosen by the sender at the time of encryption. Unlike standard IBE, our encryption scheme is escrow free in that no credential-issuing authority (or colluding set of credential-issuing authorities) is able to decrypt ciphertexts itself, providing the users' public keys are properly certified. In addition we describe a security model for the scenario in question and provide proofs of security for our scheme (in the random oracle model).     

A taxonomy of market‐based resource management systems for utility‐driven cluster computing

In utility‐driven cluster computing, cluster Resource Management Systems (RMSs) need to know the specific needs of different users in order to allocate resources according to their needs. This in turn is vital to achieve service‐oriented Grid computing that harnesses resources distributed worldwide based on users' objectives. Recently, numerous market‐based RMSs have been proposed to make use of real‐world market concepts and behavior to assign resources to users for various computing platforms. The aim of this paper is to develop a taxonomy that characterizes and classifies how market‐based RMSs can support utility‐driven cluster computing in practice. The taxonomy is then mapped to existing market‐based RMSs designed for both cluster and other computing platforms to survey current research developments and identify outstanding issues. Copyright © 2006 John Wiley & Sons, Ltd.     

Inflatable Models

A physically-based model is presented for the simulation of a new type of deformable objects-inflatable objects, such as shaped balloons, which consist of pressurized air enclosed by an elastic surface. These objects have properties inherent in both 3D and 2D elastic bodies, as they demonstrate the behaviour of 3D shapes using 2D formulations. As there is no internal structure in them, their behaviour is substantially different from the behaviour of deformable solid objects. We use one of the few available models for deformable surfaces, and enhance it to include the forces of internal and external pressure. These pressure forces may also incorporate buoyancy forces, to allow objects filled with a low density gas to float in denser media. The obtained models demonstrate rich dynamic behaviour, such as bouncing, floating, deflation and inflation.     

变化光照目标图像合成的球调和方法

光照是真实感绘制技术中的一个关键因素。研究了朗伯反射的球调和表示，提出了一种基于球调和函数的任意光照目标图像生成方法。该方法在给定目标基图像及其对应光照属性的基础上，通过基图像数据矩阵的奇异值分解（SVD）分离场景环境光分量、反演计算场景反射率和表面法向量等。新光照条件下绘制图像时，采用四阶球调和函数拟合入射光和朗伯反射核计算直接光照；间接光照采用分离出的基图像环境光分量拟合。实验表明：该方法能够保证绘制精确度，适合复杂光照条件下的目标图像生成。     

Nonlinear control techniques for an atomic force microscope system

Two nonlinear control techniques are proposed for an atomic force microscope system. Initially, a learning-based control algorithm is developed for the microcantilever-sample system that achieves asymptotic cantilever tip tracking for periodic trajectories. Specifically, the control approach utilizes a learning-based feedforward term to compensate for periodic dynamics and high-gain terms to account for non-periodic dynamics. An adaptive control algorithm is then developed to achieve asymptotic cantilever tip tracking for bounded tip trajectories despite uncertainty throughout the system parameters. Simulation results are provided to illttstrate the efficacy and performance of the control strategies.     

基于音频流的电视智能监测系统设计

广电总局的电视监测业务已经实现了设备控制自动化和卫星信号采集的数字化、信息化和网络化,但基于内容的异态事件监测和信息处理还是完全依赖人工完成.语音处理、语音识别和关联检索等技术的发展,为电视监测业务智能化提供了可能.本文介绍了电视监测业务智能辅助系统的架构,该系统能够自动定位电视节目,把电视新闻语音转化为文字,对敏感语言内容预警,并关联聚类相关信息,方便人工后续处理.     

基于内容的图像检索系统

文章介绍了基于内容的图像检索技术及其优势，并举了几个例子。     

敏感视频检测

This paper addresses the problem of detecting objectionable videos, which has never been carefully studied before. Our method can be efficiently used to filter objectionable videos on Internet. One tensor based key-frame selection algorithm, one cube based color model and one objectionable video estimation algorithm are presented. The key frame selection is based on motion analysis using the three-dimensional structure tensor. Then the cube based color model is employed to detect skin color in each key frame. Finally, the video estimation algorithm is applied to estimate objectionable degree in videos. Experimental results on a variety of real-world videos downloaded from Internet show that this method is promising.     

基于小波变换的新型暂态行波方向保护

以往的行波方向保护只对电压或电流中的一种行波波头进行信号处理,因此失去了另一电气量的信息,有时会引起方向保护的误判.为此作者提出了一种新型线路保护方案,利用小波变换提取线路故障时保护测量点的暂态电压、电流的特征量,并对二者的波形进行比较,根据其相似程度对线路的区内、区外故障作出准确、快速的判断.采用ATP(Alternative Transients Program)对各种类型故障所做的仿真计算验证了所提出的保护原理的正确性和有效性.     

配电馈线地理图到电气接线图的转换

为了将配电馈线的地理接线图转换为电气接线图,建立了基于图论的配电网模型。根据空间位置和所含节点数目对分支进行分级,将一条馈线分解成由若干分支构成的集合。在电气接线图上,遵循将偶数级分支水平放置,将奇数级分支垂直放置,并注意确保各个分支的相对走向不变的原则,按照分支级数由小到大的顺序每次添加一条分支,若产生交叉或重叠则采取水平或垂直一维局部拉伸平移法来消除,从而根据馈线的地理接线图逐步生成了电气接线图。结合实例详细说明了所提出方法的基本原理,结果表明该方法可行。