An Efficient Periodic Broadcast Technique for Digital Video Libraries

We investigate a novel multicast technique, called Skyscraper Broadcasting (SB), for digital-video-library applications. We discuss the data fragmentation technique, the broadcasting strategy, and the client design. We also show the correctness of our technique, and derive mathematical equations to analyze its storage requirement. To assess its performance, we compare it to the latest designs known as Pyramid Broadcasting (PB) and Permutation-Based Pyramid Broadcasting (PPB). Our study indicates that PB offers excellent access latency. However, it requires very large storage space and disk bandwidth at the receiving end. PPB is able to address these problems. However, this is accomplished at the expense of longer access latency and more complex synchronization. With SB, we are able to achieve the low latency of PB while using only 20% of the buffer space required by PPB.     

数码监控系统中系统数据管理策略的设计与实现

介绍了数码监控系统中存在的主要系统数据。采用面向对象程序设计的思想,给出了一个应用程序系统数据管理的方法,按此方法设汁的系统数据管理模块。易于伸缩和维护。可作为一般应用程序系统数据管理设计的模板。     

Integrated Video and Text for Content-based Access to Video Databases

This paper introduces a new approach to realize video databases. The approach consists of a VideoText data model based on free text annotations associated with logical video segments and a corresponding query language. Traditional database techniques are inadequate for exploiting queries on unstructured data such as video, supporting temporal queries, and ranking query results according to their relevance to the query. In this paper, we propose to use information retrieval techniques to provide such features and to extend the query language to accommodate interval queries that are particularly suited to video data. Algorithms are provided to show how user queries are evaluated. Finally, a generic and modular video database architecture which is based on VideoText data model is described.     

访问控制和数字版权管理

分析了传统的访问控制模型的缺陷，并从多方面对传统访问控制与作为现代访问控制技术的数字版权管理技术进行了比较，最后给出了一种包含传统的访问控制和数字版权管理的使用控制模型。     

数字版权管理系统中的角色访问控制模型

在对数字版权管理系统分析的基础上,针对数字版权管理系统的结构特点,提出了一种数字版权管理系统的角色访问控制模型。应用该模型能够减少管理开销,并能提高系统的可扩展性。该模型预测速度快,准确度较高,有很好的适应性和良好的竞争优势。     

基于工作流的数据存取权限管理

本文介绍了传统的数据存取权限管理模式，指出了基于角色的数据存取权限管理是不完整的，提出了一种新的基于工作流的数据存取权限管理模式，在工作流推进的不同时段，采用不同的存取权限表来实施存取控制，并使用Petri网来进行工作流及工作流推进的表达。     

数字电视CA系统发送端通信接口实现

通过分析条件接收(Conditional Access System,CAS)基本原理以及关键技术,研究数字电视标准中授权控制信息发生器(ECMG)、授权管理信息发生器(EMMG)、同密同步器(SCS)和复用器(MUX)之间的通信协议等,提出一种ECMG、EMMG、SCS与MUX通信的软件解决方案,用于产生授权管理信息(ECM)和授权控制信息(EMM),实现服务器与加扰机之间多线程通信。     

大数据时代数字图书馆面临的机遇与挑战

"大数据"时代的来临对现在的数字图书馆而言,既是一种发展机遇,也更是一种挑战,这种挑战甚至是颠覆性的。笔者围绕大数据与数字图书馆的内涵外沿以及关系进行多重论证进行了较为细致的分析探讨,围绕大数据时代数字图书馆面临的机遇与挑战展开分析,并基于此对大数据时代云南省的数字图书馆如何发展进行了指导建议,以便更好地发挥公共资源,发挥数字图书馆的普世价值及服务能力。     

数字版权管理中的访问控制研究

访问控制问题是数字版权管理中的一个重要安全问题.为了提高数字版权管理中的访问控制效率并降低系统实现难度,在数字版权管理系统中提出一种基于属性的访问控制模型(Attribute-Based Access Control,ABAC),并将该模型成功运用到数字化考试阅卷系统中.基于属性的访问控制模型具有逻辑严密、访问控制和安全控制具有一致性、符合面向对象设计的方法,系统易于实现等优点.该模型的提出,一方面为数字版权管理中的访问控制提供了一条新的解决方案,另一方面该模型对研究访问控制也具有一定的理论和现实意义.     

Policy Management for Secure Data Access Control in Vehicular Networks

The state-of-the-art research in vehicular network security does not address the need for low latency message access control in vehicular applications with tight connection time and message delay requirements. In existing security solutions, the major limitation is that no trust establishment mechanisms that adapt to rapidly changing scenarios and highly mobile environments (mainly because of key management delay, processing overhead, and changing communication peers). To address this issue, we present a policy management framework for secure data access control in vehicular networks. Our solution address two interrelated research areas to achieve efficiency and scalability for data access control and policy management in highly dynamic vehicular networks. The main contributions are in two-fold: (a) efficient key management and group-based policy enforcement using attribute-based cryptography; and (b) dynamic security policy management framework and methodology to manage credentials based on role, time, location and other situation dependent attributes. Our solution utilizes efficient attribute-based cryptography algorithm to achieve unprecedented speedups in message processing time to meet the real-time requirement. To demonstrate the effectiveness of our proposed solution, a systematic and comprehensive evaluation is produced to valid our proposed solution.     

基于Hi3531的ONVIF高清网络摄像机视频数据接入设计

基于海思半导体的嵌入式32位视频处理器Hi3531,提出了接入兼容ONVIF规范的高清网络摄像机视频数据的方法,描述了兼容ONVIF规范的客户端和服务器端的握手过程,介绍了H.264视频流的RTSP数据包的结构和解RTSP数据包的流程和实例.该设计被用于LED/LCD多屏拼接设备的基于IP的视频数据的接入,取得了很好的效果.     

嵌入式数字视频监控系统的数据存储策略

在基于vxWorks的嵌入式数字视频监控系统中实现了先进的存储策略,克服了dosFs文件系统自身的缺陷与不足,满足了实际应用的要求。     

嵌入式数字视频监控系统的数据存储策略

在基于vxWorks的嵌入式数字视频监控系统中实现了先进的存储策略,克服了dosFs文件系统自身的缺陷与不足,满足了实际应用的要求.     

数据访问控制系统的管理模型

建立了一个分布式，层次化和渐进性管理模型，包括3个部分：域模型、主体模型和管理角色模型，给出院 在建立管理模型时应该遵循的原则：最大基数约束，责任分离原则。     

移动数据访问系统中的事务管理

针对移动数据访问系统中事务处理的并发控制和数据访问问题,提供了一种分层的并发控制算法。另外,在弱连接或者断开连接的情况下复制的数据可以提供数据的可访问性。本文提供一个新的模式来解决带宽和数据库自治问题的限制。     

按内容访问视频数据库

文章通过分析视频数据的特点,提出了在分段基础上的层次模型和数据库的组织。在此模型的基础上,描述了视频数据库中索引的建立过程,并利用这些索引来实现按内容访问视频数据库。     

TViews: An Extensible Architecture for Multiuser Digital Media Tables

TViews is an extensible method and acoustic-based sensing framework for creating digital media tables that overcome many limitations of single-purpose systems. The system provides a means for real-time multiobject tracking on the tabletop and for the management of large numbers of objects and applications across multiple platform instances.     

Digital Preservation: A Time Bomb for Digital Libraries

The difficulty and expense of preserving digital information is a potential impediment to digital library development. Preservation of traditional materials became more successful and systematic after libraries and archives integrated preservation into overall planning and resource allocation. Digital preservation is largely experimental and replete with the risks associated with untested methods. Digital preservation strategies are shaped by the needs and constraints of repositories with little consideration for the requirements of current and future users of digital scholarly resources. This article discusses the present state of digital preservation, articulates requirements of both users and custodians, and suggests research needs in storage media, migration, conversion, and overall management strategies. Additional research in these areas would help developers of digital libraries and other institutions with preservation responsibilities to integrate long-term preservation into program planning, administration, system architectures, and resource allocation. This revised version was published online in July 2006 with corrections to the Cover Date.     

A Communication Framework for Digital Libraries

Digital libraries involve various types of data like text, audio, images and video. The data objects are typically very large and of the order of hundreds and thousands of kilobytes. In a digital library, these data objects are distributed in a wide area network. Retrieving large data objects in a wide area network has a high response time. We have conducted experiments to measure the communication overhead in the response time. We have studied the correlation between communication and size of data, between communication and type of data and the communication delay to various sites in a local and wide area network. We present different strategies for reducing delay while communicating multimedia data. Images are amenable to losing data without losing semantics of the image. Lossy compression techniques reduce the quality of the image and reduce the size leading to a lower communication delay. We compared the communication delay between compressed and uncompressed images and study the overhead due to compression and decompression. We present issues in providing digital library service to mobile users and discuss a question: What if communication were free? Finally, we present a framework for efficient communication of digital library data.