The Active XML project: an overview

This paper provides an overview of the Active XML project developed at INRIA over the past five years. Active XML (AXML, for short), is a declarative framework that harnesses Web services for distributed data management, and is put to work in a peer-to-peer architecture. The model is based on AXML documents, which are XML documents that may contain embedded calls to Web services, and on AXML services, which are Web services capable of exchanging AXML documents. An AXML peer is a repository of AXML documents that acts both as a client by invoking the embedded service calls, and as a server by providing AXML services, which are generally defined as queries or updates over the persistent AXML documents. The approach gracefully combines stored information with data defined in an intensional manner as well as dynamic information. This simple, rather classical idea leads to a number of technically challenging problems, both theoretical and practical. In this paper, we describe and motivate the AXML model and language, overview the research results obtained in the course of the project, and show how all the pieces come together in our implementation. The first and third authors were partially funded by the European Project Edos. Work done when the second and third authors were at INRIA. Work done when the second and third authors were at INRIA.     

Active XML文档有效性检验

文档有效性检验是XML领域的一个基本问题.Active XML(AXML)文档在XML文档中引入Web服务,传统用于解决XML文档有效性的检验方法并不适用于AXML文档,为文档有效性检验提出了新的挑战.研究了AXML文档有效性检验问题,在原始树自动机的基础上,定义了AXML模式树自动机-ASTA机,该树自动机能够有效地描述满足AXML模式约束的文档集合.基于ASTA机,提出了一种多项式时间的AXML文档有效性检验算法.实验数据表明,基于提出的算法能够有效的完成对AXML文档的有效性检验.     

基于形式语言理论的Active XML重写算法

主动XML（AXML）是指一部分数据直接给出,另一部分数据以Web Services调用方式隐含给出XML文档。研究AXML重写问题,给出AXML重写系统的形式化定义,提出一个基于树自动机理论的AXML文档重写算法,并证明该算法的正确性及有效性。实验数据表明,基于树自动机的AXML文档交换方法具有良好的执行效率。     

基于Active XML的动态Web服务组合实现

随着Web服务应用的发展，大量存在的应用服务之间需要解决共享和交互，动态Web服务组合为解决信息共享和应用协作的瓶颈问题提供了新的方案。该文通过引入Active XML（AXML），扩展Web服务，提出了一个基于Active XML的动态Web服务组合框架，在此基础上实现了一个动态服务体系结构。该体系结构支持组合服务的即时生成以及在动态环境中的快速部署和发布。     

Active XML-based Web data integration

Today, the Web is the largest source of information worldwide. There is currently a strong trend for decision-making applications such as Data Warehousing (DW) and Business Intelligence (BI) to move onto the Web, especially in the cloud. Integrating data into DW/BI applications is a critical and time-consuming task. To make better decisions in DW/BI applications, next generation data integration poses new requirements to data integration systems, over those posed by traditional data integration. In this paper, we propose a generic, metadata-based, service-oriented, and event-driven approach for integrating Web data timely and autonomously. Beside handling data heterogeneity, distribution and interoperability, our approach satisfies near real-time requirements and realize active data integration. For this sake, we design and develop a framework that utilizes Web standards (e.g., XML and Web services) for tackling data heterogeneity, distribution and interoperability issues. Moreover, our framework utilizes Active XML (AXML) to warehouse passive data as well as services to integrate active and dynamic data on-the-fly. AXML embedded services and changes detection services ensure near real-time data integration. Furthermore, the idea of integrating Web data actively and autonomously revolves around mining events logged by the data integration environment. Therefore, we propose an incremental XML-based algorithm for mining association rules from logged events. Then, we define active rules dynamically upon mined data to automate and reactivate integration tasks. Finally, as a proof of concept, we implement a framework prototype as a Web application using open-source tools.     

Active XML文档物化终止性检验算法

Active XML（简记为AXML）文档在XML文档中引入嵌入式Web服务,通过调用这些服务,来获取相应的内涵信息,为AXML文档物化过程。研究了AXML文档物化的终止性检验问题,提出了多项式时间的检验算法,该算法通过构造AXML模式依赖图,检验其无环性来判定AXML文档物化终止性问题,证明了算法的正确性和有效性。     

ARAXA: Storing and managing Active XML documents

Active XML (AXML) documents combine extensional XML data with intentional data defined through Web service calls. The dynamic properties of these documents pose challenges to both storage and data materialization techniques. In this paper, we present ARAXA, a non-intrusive approach to store and manage AXML documents. We also define a methodology to materialize AXML documents at query time. The storage approach of ARAXA is based on plain relational tables and user-defined functions of Object-Relational DBMS to trigger the service calls. By using a DBMS we benefit from efficient storage tools and query optimization. Approaches without DBMS support have to process XML in main memory or provide for virtual memory solutions. One of the main advantages of ARAXA is that AXML documents do not need to be loaded into main memory at query processing time. This is crucial when dealing with large documents. The experimental results with ARAXA prototype show that our approach is scalable and capable of dealing with large AXML documents.     

基于XML元素加密的Web服务安全策略

Web服务使开发人员能够建立一种面向服务的、平台无关的、分布式的应用程序架构,另一方面Web服务使用XML在网络中进行数据交换,如何提高Web服务的安全性则成为需要解决的关键问题。本文论述了基于对XML文件中的元素进行加密的策略,从而保证了Web服务安全性。     

基于Web services的XML引擎安全模型研究*

Web services提供软件接口,实现Internet上服务的调用。它以XML为基础,使用了基于XML语言的协议来描述要执行的操作或要与另一个Web服务交换的数据。SOAP是Web services的传输层协议,所有的SOAP消息均使用XML编码。XML engine是建立在Web service上的一种技术。在整个Web服务应用中,XML处于消息层的位置,而XML engine则针对Web服务应用中的XML进行操作,所以称做消息层网关。在XML engine平台上,通过动态共享对象(DSO)机制,将     

Data storage practices and query processing in XML databases: A survey

With the rapid emergence of XML as a data exchange standard over the Web, storing and querying XML data have become critical issues. The two main approaches to storing XML data are (1) to employ traditional storage such as relational database, object-oriented database and so on, and (2) to create an XML-specific native storage. The storage representation affects the efficiency of query processing. In this paper, firstly, we review the two approaches for storing XML data. Secondly, we review various query optimization techniques such as indexing, labeling and join algorithms to enhance query processing in both approaches. Next, we suggest an indexing classification scheme and discuss some of the current trends in indexing methods, which indicate a clear shift towards hybrid indexing.     

XML-based specification for Web services document security

The Internet and related technologies have seen tremendous growth in distributed applications such as medicine, education, e-commerce, and digital libraries. As demand increases for online content and integrated, automated services, various applications employ Web services technology for document exchange among data repositories. Web services provide a mechanism to expose data and functionality using standard protocols, and hence to integrate many features that enhance Web applications. XML, a well-established text format, is playing an increasingly important role in supporting Web services. XML separates data from style and format definition and allows uniform representation, interchange, sharing, and dissemination of information content over the Internet. XML and Web services provide a simplified application integration framework that drives demand for models that support secure information interchange. Providing document security in XML-based Web services requires access control models that offer specific capabilities. Our XML-based access control specification language addresses a new set of challenges that traditional security models do not address.     

基于XML Web 服务的产品数据共享模型研究

提出了基于XML Web服务的产品数据共享模型。首先,分析将产品数据作为服务发布的意义,并制定以XML Web服务方式共享产品数据的原则;其次,探讨了产品数据XML Web服务中二进制数据的发布的问题;最后,提出基于XML Web服务的产品数据共享体系结构。     

XML语言及相关技术综述

作为数据表示的一个开放标准,XML语言给Web应用乃至网络计算注入了新的活力。文中给出了XML的简介,包括设计背景、关键特性、相关技术标准,讨论了XML的用途及应用开发技术,探讨了WXL与对象技术的协作及发展趋势。     

A method for the unification of XML schemata

Extensible Markup Language (XML) is a common standard for data representation and exchange over the Web. Considering the increasing need for managing data on the Web, integration techniques are required to access heterogeneous XML sources. In this paper, we describe a unification method for heterogeneous XML schemata. The input to the unification method is a set of object-oriented-based canonical schemata that conceptually abstract local Document Type Definitions of the involved sources. The unification process applies specific algorithms and rules to the concepts of the canonical schemata to generate a preliminary ontology. Further adjustments on this preliminary ontology generate a reference ontology that acts as a front-end for user queries to the XML sources.     

XML元素级检索的反馈算法

XML作为网上数据表示和交换的标准具有日益广泛的应用。近年来，XML元素级检索得到越来越多信息检索领域研究者的关注。如何提高XML元素级检索效果已经成为一个重要的研究课题。在LEMUR系统里实现了一种针对XML元素级检索的新反馈算法，大幅度地提高了检索结果的精度。利用INEX提供的XML文档集、评测系统等进行了长期的实验。实验数据显示，该算法以内容作为反馈信息使系统的平均精度提高了15.70%，以内容和结构作为反馈信息使系统的平均精度提高了18.19%。     

XML数据索引技术

对XML数据建立有效的索引,是左右XML数据处理性能的重要因素.深入地讨论了目前XML索引技术的研究现状,将XML索引技术分为两大类:节点记录类索引(本身还可以分为3个小的类型)和结构摘要类索引.根据XML数据查询处理效率以及XML数据修改对XML索引的要求,讨论了相关XML索引方法的优点和不足,并归结出XML索引后续研究的3个方向:XML结构信息的获取,路径信息的多维处理,数据修改合法性的有效支持,以及涉及能够同时有效满足XML查询和信息获取的索引.     

一种Active XML模式重写算法

基于树自动机理论,研究了Active xML(简记为AXML)模式重写问题,提出了一种多项式时间的AXML模式重写判定算法,并对算法进行了实现.实验结果证明了所提算法用于判定AXML模式重写的优越性.     

XML数据的查询技术

XML规范已成为当前网络应用(包括数字图书馆、Web服务以及电子商务)中事实上的数据表达、交换的标准.针对XML数据的查询在当前XML数据管理研究中占有重要的地位,也是当前XML数据处理研究领域的热点方向,相关的研究文献有很多.根据查询模式描述的不同,将当前XML查询技术归入两大类:XML Query方式和XML IR方式.后者又进而可分以为3个子类:XML IR/keyword方式、XML IR/fragment和XML IR/query方式,并从中挑选出3个研究者关注的问题进行了简述,它们是:Twig查询模式的处理、SLCA(smallest lowest common ancestor)节点的获取以及对所获取的XML片段相似性的度量.以方便普通用户使用为准则探讨了相关XML查询技术的优、缺点,将如下4个问题作为需要进一步关注的研究内容:结构化关键字查询及相应的结构相似性度量方法,如何消除XML Query查询处理模式(包含XML IR/query)和XML IR/keyword查询处理模式间数据冗余的问题,XML Query查询方式的理论探讨及其实现以及针对特定应用的XML数据的有效管理.     

基于XML与Web服务的多源气田信息整合

气田信息整合的主要目标是实现自治、分布、异构数据源的自动数据交换，并为用户提供统一的全局数据视图。Web服务作为一种面向服务的分布式计算技术，提供了一种建立基于Web的复杂松耦合分布式系统框架。讨论了Web服务应用于信息整合的基本模式，提出了基于Web服务的气田信息整合体系结构和基于元数据的气田信息整合方法。系统采用XML作为数据表示和交换的标准，具有较强的灵活性和可维护性。