Packaging models for the storage and distribution of complex digital objectsin archival information systems: a review of MPEG-21 DID principles

In recent years, the number of organizations making digital information available has increased dramatically. This evolution has encouraged the development of various approaches to represent complex digital objects. Approaches that are of specific relevance to the digital library and archiving community include the Metadata Encoding and Transmission Standard (METS), the Content Packaging XML Binding of the Instructional Management System (IMS) project, and the Sharable Content Object Reference Model (SCORM). The MPEG-21 Digital Item Declaration MPEG-21 DID) is yet another packaging approach that, so far, has received little attention in the digital library community. The primary goal of this article is to offer a method to compare these packaging approaches in the context of the needs of the digital library community and the rising digital preservation programs. The contribution of this paper is the definition of an integrated reference framework, based on both the ISO OAIS Reference Model and a set of additional significant properties that affect the quality, usability, encoding, and behavior of complex digital objects. This article also gives a brief insight into MPEG-21 DID and examines its potential relevance by showing the results obtained from applying the proposed reference framework. Published online: 8 April 2005     

MPEG-21 digital item declaration and Identification-principles and compression

At the core of the MPEG-21 Multimedia Framework is the concept of the Digital Item, a virtual container for a hierarchical structure of metadata and resources. This paper considers the Digital Item Declaration Language (DIDL), gives examples of its usage, and discusses how it is used to integrate other parts of MPEG-21. The paper then discusses how Digital Item Identification integrates with the DIDL to allow MPEG-21 to utilize standard identifiers from many application spaces. Finally, an alternative, compressed form of the XML Digital Item Declaration is described. This uses schema-based compression to significantly reduce the size of these XML documents.     

基于感知运动能量模型的MPEG-21数字项适配

最新的MPEG-21标准定义了一个统一的多媒体框架,其目标是使多媒体资源能在异构网络和终端上进行透明传输和得到充分利用。多媒体适配(Multimedia Adaptation)技术作为实现上述目标的关键技术得到了越来越多的研究。本文将感知运动能量模型与MPEG-21数字项适配框架相结合,研究和实现了基于感知运动能量的H．264／AVC视频丢帧适配技术。本文的研完工作有两个方面的优点：一方面,感知运动能量模型的使用将丢帧适配引起的运动抖动减至最小,保证了较高的用户视觉上的主观感知质量;另一方面,数据处理能力和资源受限的适配节点不需了解具体的H．264／AVC编码语法结构和编解码算法,就能方便地执行丢帧操作,实现了独立于媒体编码格式的视频适配机制,提高了多媒体适配系统的灵活性和可扩展性。     

Digital item adaptation: overview of standardization and research activities

MPEG-21 Digital Item Adaptation (DIA) has recently been finalized as part of the MPEG-21 Multimedia Framework. DIA specifies metadata for assisting the adaptation of Digital Items according to constraints on the storage, transmission and consumption, thereby enabling various types of quality of service management. This paper provides an overview of DIA, describes its use in multimedia applications, and reports on some of the ongoing activities in MPEG on extending DIA for use in rights governed environments.     

Visual content adaptation according to user perception characteristics

Adapting multimedia content to users' preferences and perceptual characteristics is a key direction for enabling personalized multimedia services. In this paper, we address the problem of tailoring visual content within the MPEG-21 Digital Item Adaptation (DIA) framework to meet users' visual perception characteristics. In particular, we present methods for adapting visual content to accommodate color vision deficiency and low-vision capabilities. In addition, we present methods for adapting visual content according to user preferences for color temperature. Finally, we report on experiments that adapt visual content within the MPEG-21 DIA framework.     

XML数字签名在电子政务中的应用

本文介绍了电子政务概念以及电子政务信息安全现状,重点探讨了XML数字签名技术及其与传统数字签名技术的不同之处,最后实现在电子政务中的具体应用.     

数字图书馆网格互操作框架

随着全球数字图书馆(DLs)的迅猛发展,互操作成为亟待解决的重要问题。目前DLs互操作的主要解决方案包括:分布式搜索、元数据收集、中间件技术等,在实现大规模的数字图书馆互操作方面都存在一定的局限性。文章通过对已有方案的分析和对比,指出各自的优势和不足,并在OAI-PMH框架的基础上,结合先进的网格技术,提出全新的数字图书馆互操作框架—数字图书馆网格DLGrid,为解决大规模数字图书馆的互操作提供一种新途径。     

Preference-driven personalization for flexible digital item adaptation

The delivery of multimedia content often needs the adaptation of the content in order to satisfy user constraints. With the Digital Item Adaptation part, the MPEG-21 standard already defines a useful frame-work to handle this task. However, in modern service-oriented architectures the functionality of adaptation is split over several services. Hence, the central instantiation of a suitable service chain needs to tackle a complex multi-objective optimization problem. In this problem between content choice and possible adaptations the current preference model in the MPEG-7/21 standard still lacks expressiveness. In the course of this paper we demonstrate this shortcoming and how the integration of more powerful models can ease the instantiation problem. Furthermore we explain how to efficiently evaluate preference trade-offs by evaluating skyline queries as currently investigated in the field of information systems. As a running example we use preference-based content adaptation in a typical media streaming application with Web services as basic modules. The contribution of our framework is to enable a central coordinator to instantiate an executable service composition chain by integrating all needed Web services to adapt the multimedia content in the best possible fashion in the sense of Pareto optimality. This work was supported in part by the German Research Foundation (DFG) within the Emmy-Noether Program of Exellence.     

MPEG的新发展——多媒体框架标准MPEG-21

标准化是产业化活动成功的前提，视、音频编码的各种国际标准的制定集中地反映了视、音频编码技术发展的水平．目前，图象压缩方面的标准主要有MPEG系列(MPEG-1，MPEG-2，MPEG-4，MPEG-7和MPEG-21标准)，以及H．26X系列(H．261，H．263标准)和静止图象压缩标准JPEG．为了使人们对图象压缩标准有所了解，以进一步推动图象压缩方面的研究，首先对MPEG系列的各种已有标准及其应用进行了概述，然后着重讨论了MPEG中的新面孔——正在开发的MPEG-21标准，并就其目标、用户需求、技术要素、关键任务、应用领域以及工作计划做了较详细的描述．     

如何应用数字图书馆

文章通过介绍数字图书馆的有关知识和中国期刊全文数据库(简称CNKI)的使用方法,拟在帮助和提高读者应用数字图书馆的能力,使数字图书馆,能更好的成为读者手中的工具。     

The MPEG-21 rights expression language and rights data dictionary

The MPEG-21 Rights Expression Language (REL) is an XML-based language for digital rights management (DRM), providing a universal method for specifying rights and conditions associated with the distribution and use of assets like content, resources and services. Evolved from the eXtensible rights Markup language (XrML), the REL facilitates the creation of an open DRM architecture for managing and protecting these assets. As a general-purpose rights expression language, the REL is agnostic to types of assets, platforms and media, and expressive enough to support applications that can be even beyond DRM, including protecting privacy. It also contains additional capabilities in the areas of extensibility, security, trust management, and life cycle management of rights. This article provides an overview of the REL in terms of its data model, expressiveness, authorization model, structure for extensibility and profiling, and usages in digital media, trust management, and web services. To support the REL and provide extensive semantics for the management of rights, MPEG-21 also defined a Rights Data Dictionary (RDD). Based on original work conducted by , the MPEG-21 RDD specifies a methodology and structure for the RDD dictionary. The specification defines a core set of terms and provides a mechanism for the introduction of further terms through a registration authority. The RDD also supports the mapping of terms from different namespaces.     

XML数字签名

XML作为一种与平台无关的描述性语言 ,以其高度的可扩展性而被广泛的应用。概述了XML与数字签名技术 ,介绍了XML数字签名规范 ,并以一个应用为例说明该规范的实施 ;最后展望并简略介绍其它的一些XML数字签名方案。     

An evaluation study of a digital library of ideas: Workflow Model and classroom use

The Department of Design Manufacturing and Engineering Management at the University of Strathclyde, Glasgow, UK, has been developing a digital library to support design engineering student learning through the Digital Libraries for Global Distributed Innovative Design Education and Teamwork project (, December, 2007). Previous related studies have observed and analysed how students search for, store, structure and share design engineering information (Grierson et al. in paper presented at the Network Learning Conference, pp. 572–579, 2004; Nicol et al. in Open Learning 20(1):31–49, 2005) and these studies have identified the need for the design and development of a digital library with two system components, which best suit the design process: (i) an informal shared workspace; the ‘LauLima’ Learning Environment and (ii) a repository of more formal searchable and browsable design information; the ‘LauLima’ Digital Library (McGill et al. in Br. J. Educ. Technol. 36(4):629–642, 2005). This paper focuses on the Workflow Model developed to populate the digital library and presents findings from early use of the digital library by students and staff.     

XML数字签名在电子订单系统中的应用

随着XML越来越广泛的应用,XML数据的安全问题已成为人们关注的焦点。针对电子订单系统中存在的XML数据签名需求,提出基于代理的XML数字签名解决模型,订单数据传输给代理系统执行数字签名和有效验证。该模型提供签名与验证的功能接口,保证系统的可移植性,同时应用Java实现了XML数字签名和验证过程,进一步提高了系统的跨平台能力。     

基于XML的元数据相关应用研究

元数据作为一种编码体系,在数据管理中占据着重要的地位。本文从元数据的概念、相关格式、携带工具(RDF),以及XML的相关概念入手,探讨了元数据的资源描述框架(RDF)及其在数字图书馆和数字博物馆中的应用。