数字图书馆信息检索技术

本文讨论了数字图书馆中文本、图像、音频、视频等媒体基于内容的信息检索技术 ,介绍了人工智能在数字图书馆信息检索中的应用 ,提出利用知识发现技术和智能信息推拉技术构造数字图书馆的智能信息检索系统 ,向用户提供主动的、个性化的信息服务。     

边界描迹算法在图像数据库的应用

本文介绍了一种优化图像数据库性能的算法－边界描迹算法,通过形态学变换减少笔迹图像的孤立点噪声,采用边界描迹的方法提取图像的基本特征,并以链码形成存储图像数据。可以大大减少图像数据的存储量,本文详细阐述了此方法的算法实现。     

一种采用神经网络实现解扩的扩频系统

本文分析比较了目前常见的几种解扩方法的各自特点,提出了一种采神经网络解扩的直接序列扩频通信系统,并用ＭＡＴＬＡＢ提供的神经网络工相进行了仿真。仿真结果表明：文中提出的采用神经网络实现对直接序列扩频信号解扩的方案是鸽是可行的。而且这种方法可以通过训练和学习使系统具有很强的自适应性,以适应信道传输特性的变化,可以说是一种自适应解扩方法。     

数字水印技术

数字技术与互联网络的发展对传统的版权保护手段提出了挑战,作为一个解决数字产品版权保护的新方法,数字水印技术在最近几年引起人们的极大关注,目前已提出了多种数字水印方案,本文首先介绍了数字水印的主要应用方面,而后描述了这些方案所共有的总体框架与特性,介绍了数字水印的生成、嵌入与恢复方法,最后简单分析了数字水印的研究方向与应用前景以及数字水印方法可能存在的一些问题。     

Ontology-driven document enrichment: principles, tools and applications

In this paper, we present an approach to document enrichment, which consists of developing and integrating formal knowledge models with archives of documents, to provide intelligent knowledge retrieval and (possibly) additional knowledge-intensive services, beyond what is currently available using “standard” information retrieval and search facilities. Our approach is ontology-driven, in the sense that the construction of the knowledge model is carried out in a top-down fashion, by populating a given ontology, rather than in a bottom-up fashion, by annotating a particular document. In this paper, we give an overview of the approach and we examine the various types of issues (e.g. modelling, organizational and user interface issues) which need to be tackled to effectively deploy our approach in the workplace. In addition, we also discuss a number of technologies we have developed to support ontology-driven document enrichment and we illustrate our ideas in the domains of electronic news publishing, scholarly discourse and medical guidelines.     

QoS Management in Educational Digital Library Environments

Advances in multimedia computing technologies offer new approaches to the support of computer-assisted education and training within many application domains. Novel interactive presentation tools can be built to enhance traditional teaching methods with more active learning. Since a variety of user expectations are possible in such an environment, research must address the incorporation of these factors into presentation tools. During an interactive learning/training process, presentation tools must be able to handle various types of delays. A flexibly adjustable quality of service (QoS) should thus be supported. In this paper, we investigate a framework and systematic strategies for supporting the continuous and synchronized retrieval and presentation of multimedia data streams in a client/server distributed multimedia environment for educational digital libraries. Specifically, we establish a practical framework for specifying multimedia objects, tasks, schedules, and synchronization constraints between media streams. We identify the QoS parameters critical to the support of multimedia presentations for learning and training activities. Based on the proposed framework and QoS specifications, we develop presentation scheduling and buffer management strategies which can enforce the specified QoS requirements in an educational digital library environment.     

Emergent Properties of a Market-based Digital Library with Strategic Agents

The University of Michigan Digital Library (UMDL) is designed as an open system that allows third parties to build and integrate their own profit-seeking agents into the marketplace of information goods and services. The profit-seeking behavior of agents, however, risks inefficient allocation of goods and services, as agents take strategic stances that might backfire. While it would be good if we could impose mechanisms to remove incentives for strategic reasoning, this is not possible in the UMDL. Therefore, our approach has instead been to study whether encouraging the other extreme—making strategic reasoning ubiquitous—provides an answer.Toward this end, we have designed a strategy (called the p-strategy) that uses a stochastic model of the market to find the best offer price. We have then examined the collective behavior of p-strategy agents in the UMDL auction. Our experiments show that strategic thinking is not always beneficial and that the advantage of being strategic decreases with the arrival of equally strategic agents. Furthermore, a simpler strategy can be as effective when enough other agents use the p-strategy. Consequently, we expect the UMDL is likely to evolve to a point where some agents use simpler strategies and some use the p-strategy.     

水体下综放开采可行性分析

余吾煤业现有630万吨煤炭资源处在绛河水体下,煤层厚度在4.0～6.2m之间,现导水裂隙带经验公式不能够满足其水体下安全开采,存在开采后突水隐患,为了确定开采后上覆岩层导水裂隙带极限高度是否波及地表,研究区在9个井下钻孔进行了井下仰孔双栓塞分段注水测试和仰孔直观法电视成像仪探测,对涌水量进行了监测、水质进行了对比研究,并通过模拟实验进一步研究不同采厚条件下发育高度.观测、监测及模拟结果表明:采动后导水裂隙带发育高度取决于采厚,为水体下采煤水的防治提供了可靠数据,三个工作面的试采成功,为水体下采煤提供了应用范例.     

三维协同设计在水利设计院中的应用

论述了三维协同设计在河北省水利水电勘测设计研究院中的实践,阐明了其应用理念和管理实施架构,结合双峰寺水库项目。介绍了三维协同设计的具体应用。     

基于二重循环的数字水印算法

针对现有数字水印算法中存在的抵抗联合攻击能力差、水印提取准确率不高等问题,提出了一种基于分块快速傅里叶变换(FFT)的二重循环数字水印算法.先进行图像大小归一化,对其进行分块FFT变换,在每个图像块的FFT系数中通过大小关系调制嵌入若干比特水印,水印按照二重循环嵌入.提取时从任何一个包括所有水印的图像部分中,直接通过判断FFT系数的大小关系来提取水印.实验结果表明,该算法能抵抗滤波加噪等常规信号处理攻击,JPEG压缩等压缩攻击,旋转、缩放、平移等全局几何攻击和裁剪、拼贴等特殊攻击以及它们的联合攻击,并且误码率低,接近0.