PowerPoint2000动画设计应用

PowerPoint2000是Microsoft公司办公自动化软件Office2000的重要构件之一。其自身具有强大的处理功能，尤其是PowerPoint2000所提供的基本动画效果，更是给演示文稿增添了很多色彩。如果能将这些基本动画效果巧妙地组合在一起，就会创作出更富感染力的作品。就创作中的技巧并结合应用举例分析如下。相信人们可以利用这些设计思想，创作出更加精彩的作品。     

An innovative technique for web text watermarking (AITW)

ABSTRACT

Embedding a hidden stream of bits in a cover file to prevent illegal use is called digital watermarking. The cover file could be a text, image, video, or audio. In this study, we propose invisible watermarking based on the text included in a webpage. Watermarks are based on predefined structural and syntactic rules, which are encrypted and then converted into zero-width control characters using binary model classification before embedding into a webpage. This concept means that HTML (Hyper Text Markup Language) is used as a cover file to embed the hashed and transparent zero-width watermarks. We have implemented the proposed invisible watermarking against various attacks to reach optimum robustness.     

Key-dependent 3D model hashing for authentication using heat kernel signature

Multimedia-based hashing is considered an important technique for achieving authentication and copy detection in digital contents. However, 3D model hashing has not been as widely used as image or video hashing. In this study, we develop a robust 3D mesh-model hashing scheme based on a heat kernel signature (HKS) that can describe a multi-scale shape curve and is robust against isometric modifications. We further discuss the robustness, uniqueness, security, and spaciousness of the method for 3D model hashing. In the proposed hashing scheme, we calculate the local and global HKS coefficients of vertices through time scales and 2D cell coefficients by clustering HKS coefficients with variable bin sizes based on an estimated L² risk function, and generate the binary hash through binarization of the intermediate hash values by combining the cell values and the random values. In addition, we use two parameters, bin center points and cell amplitudes, which are obtained through an iterative refinement process, to improve the robustness, uniqueness, security, and spaciousness further, and combine them in a hash with a key. By evaluating the robustness, uniqueness, and spaciousness experimentally, and through a security analysis based on the differential entropy, we verify that our hashing scheme outperforms conventional hashing schemes.     

VB教学方法浅析

程序设计是计算机专业课程中的重要内容之一。在程序设计课程教学中,如何解决程序设计本身枯燥、难懂这个问题,找到一条比较新颖的教学方式,一直是广大计算机教师颇感兴趣的课题。结合几年来VB程序设计的实际经验,并进行深刻的反思,总结出一个四步教学法。     

基于网络处理器的零拷贝技术*

通过分析网络处理器系统的收发机制,提出了一种基于网络处理器的零拷贝技术。该技术不仅实现了在网络处理器系统下的零拷贝技术,而且也体现出网络处理器中不同数据处理层的协作框架。     

Are Cyberbullies really bullies? An investigation of reactive and proactive online aggression

Cyberbullying, or online aggression, is an issue of increasing concern, however little research has been conducted on the motivations underlying this form of aggression. Using a mixed-method approach, by means of survey and interview data, we explored whether online aggressive acts were motivated by proactive (intentionally aggressing to obtain a resource or a goal), and/or reactive (aggression that occurs in reaction to provocation) reasons. Participants for the survey portion of the study included 733 adolescents between the ages of 10 and 18, while a subset of 15 adolescents participated in semi-structured interviews. Factor analysis revealed that, in contrast to traditional forms of bullying, adolescents do not identify themselves according to the role they played in an internet aggressive situation (i.e. bully, victim, witness), but according to the method of aggression they used (i.e. sending mean messages, posting embarrassing photos, and developing hostile websites). More interestingly, regression analyses demonstrated that motivations for aggressing online also varied according to method of aggression rather than role. For example, adolescents who chose to aggress by posting mean messages or posting embarrassing photos were more likely to do so for reactive reasons, while adolescents who spent time creating hostile websites did so for proactive reasons.     

无线移动自组织网路由协议综述

本文首先简单介绍了Adhoc网的概貌，然后全面介绍了Adhoc网的路由协议。包括平面路由协议和分层路由协议，先验式和反应式路由协议以及GPs辅助型路由协议。     

轨枕养护温控系统数据备份与恢复的实现

针对轨枕养护温控系统数据量大的特点,系统实现了对数据库分卷备份、分卷恢复的功能。一年多的运行证明,该方法的有效性。     

基于音频的视频拷贝检测

提出了一个兼具实时性和鲁棒性的短视频拷贝检测框架,并以长视频中的广告检测为应用进行研究.框架主要分为两个部分：1.基于音频匹配的短视频拷贝检测;2.基于图像的边界精确定位.第一阶段从原始视频中获得声谱图,并进一步地提取出音频特征并在音频库中寻找匹配;在第二阶段,对检测到的视频片段进行合并,然后利用视频片段在边界处附近的图像特征,对边界片段进行精确定位.实验结果显示,准确率高达99％,取得了很好的效果.     

基于随机Petri网的P2P存储系统可靠性模型和分析

可靠性是可信性研究的基本内涵之一,也是P2P ( Peer-to-Peer)存储系统研究的关键。P2P存储系统结点具有高动态特征,结点频繁地上下线给系统的可靠性分析带来困难。结点的暂时离线会增加副本数量,从而导致系统不必要的损耗。较多的副本数量会增加系统的可靠性,但是同时会导致系统的一致性维护成本增加。而较少的副本数量又会导致系统的可靠性显著降低。针对副本的数量和可靠性之间的关系,采用随机Pctri建立了P2P存储系统的可靠性模型并加以分析,围绕数据可靠性度量要求和数据副本的数量建立关系模型,从理论上指明研究系统可靠性的目的和基本原则,这可以在系统组建之初帮助优化系统的设计。