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.     

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。     

Active XML文档重写机制的研究

Active XML定义为一种动态的XML,主要思想是在XML中嵌入Web Services调用.当Active XML文档用作表示和交换时,通过调用相应的Web Services ,用返回结果取代Active XML文档中的Web Services调用或者作为子节点插入,这个过程称为重写.针对应用要求不同的场景,总结了两类重写方式无模重写,即在重写时不受Schema约束;有模重写,重写时要符合预定的Schema.在对无模方式做了简单讨论后,对有模方式的算法做了详细讨论,为拓展Active XML技术的应用领域提供了技术支持.     

On the improvement of active XML (AXML) representation and query evaluation

Active XML (AXML) as intensional data aims to exploit potential computing powers of XML, Web services and P2P architecture. It is considered a powerful extension of XML to deal with dynamic XML data from autonomous and heterogeneous data sources on a very large scale via Web services. However, AXML is still at an immature stage and various issues need to be investigated before it can be accepted widely. This paper will focus on two issues facing the current AXML system, namely the representation and the query process. We propose superior representation and improved query evaluation for AXML. For justification purposes, we compare our proposed algorithms with the existing algorithms.     

Active XML文档安全重写判定算法

研究了AXML文档安全重写判定问题,即判定给定AXML文档通过触发其包含的服务调用生成的文档集合是否能够全部重写为符合目标模式的文档实例.基于树自动机理论,定义了用于抽象AXML文档的树自动机--ATA机(AXML treeautomata),ATA机等价于给定AXML文档通过触发其包含的服务调用所能生成的文档集合.基于ATA机,提出一个AXML文档安全重写判定算法,表明了该算法的正确性及有效性.     

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.     

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.     

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     

Millau: an encoding format for efficient representation and exchange of XML over the Web

XML is poised to take the World Wide Web to the next level of innovation. XML data, large or small, with or without associated schema, will be exchanged between increasing number of applications running on diverse devices. Efficient storage and transportation of such data is an important issue. We have designed a system called Millau for efficient encoding and streaming of XML structures. In this paper we describe the Millau algorithms for compression of XML structures and data. Millau compression algorithms, in addition to separating structure and text for compression, take advantage of the associated schema (if available) in compressing the structure. Millau also defines a programming model corresponding to XML DOM and SAX for XML APIs for Millau streams of XML documents. Our experiments have shown significant performance gains of our algorithms and APIs. We describe some of these results in this paper. We also describe some applications of XML-based remote procedure calls and client-server applications based on Millau that take advantage of the compression and streaming technology defined by the system.     

Efficient execution of composite Web services exchanging intensional data

Web service technologies provide a standard means of integrating heterogeneous applications distributed over the Internet. Successive compositions of new Web services using pre-existing ones usually create a hierarchical structure of invocations among a large number of Web services. For the efficient execution of these composite Web services, we propose an approach which exploits intensional XML data, i.e. an XML document that contains special elements representing the calls to Web services, in order to delegate the invocations of the external Web services to some relevant nodes. We formalize an invocation plan for composite Web services in which intensional data is used as their parameters and results, and define a cost-based optimization problem to obtain an efficient invocation plan for them. We provide an A∗ heuristic search algorithm to find an optimal invocation plan for a given set of Web services and also present a greedy method of generating an efficient solution in a short time. The experimental results show that the proposed greedy method can find a close-to-optimal solution efficiently and has good scalability for a complex call hierarchy of Web services.     

Personalised ubiquitous file access with XML Web Services

The explosion of new types of end-user devices, as well as the increase in the number of users with broadband connection in private households, opens up the opportunity to provide access to documents and services residing in the home domain from remote locations. Also, the increased mobility of users, as well as the need to be able to work in all locations, further adds to the requirement of remote document access. The contribution of this paper is threefold. First, it introduces the Mobile Home Access system, which simplifies remote access to resources in a home domain. The Mobile Home Access (MHA) system is based on the Service-Oriented Computing concept and realized using XML Web Services for communication between the home domain and the end-user device, while employing the Common Internet File System (CIFS) network file system to allow appropriate file access in the home domain. The second contribution is the mechanism whereby such a service can be deployed when network elements like firewalls and NAT routers are introduced. The challenge of establishing a connection from a remote device is general for both client–server services and peer-to-peer services. The paper proposes and describes a design and implementation of a solution using XML Web Services technologies, and thus shows how NAT traversal technology can be integrated with such middleware. The third contribution of this paper is a performance analysis of the current implementation of the Mobile Home Access service. The results of the analysis should be interesting for the applicability of XML Web Services in mobile computing in general.     

基于XMLBeans和Web服务技术构建SOA

目前,Web服务技术是构建SOA的最好方法,而服务间一般通过XML数据进行消息传递.XMLBeans是一种将XML实例和底层架构映射为JavaBeans风格的对象的XML-Java绑定工具,完全使用面向对象的观点来看待和处理数据和文档.结合税务项目开发体会探讨了SOA的概念和相关技术,并给出了一个简单的基于XMLBeans和Web服务技术构建的SOA的部分实现.     

Comparative Analysis of XML Compression Technologies

XML provides flexibility in publishing and exchanging heterogeneous data on the Web. However, the language is by nature verbose and thus XML documents are usually larger in size than other specifications containing the same data content. It is natural to expect that the data size will continue to grow as XML data proliferates on the Web. The size problem of XML documents hinders the applications of XML, since it substantially increases the costs of storing, processing and exchanging the data. The hindrance is more apparent in bandwidth- and memory-limited settings such as those applications related to mobile communication. In this paper, we survey a range of recently proposed XML specific compression technologies and study their efforts and capabilities to overcome the size problem. First, by categorizing XML compression technologies into queriable and unqueriable compressors, we explain the efforts in the representative technologies that aim at utilizing the exposed structure information from the input XML documents. Second, we discuss the importance of queriable XML compressors and assess whether the compressed XML documents generated from these technologies are able to support direct querying on XML data. Finally, we present a comparative analysis of the state-of-the-art XML conscious compression technologies in terms of compression ratio, compression and decompression times, memory consumption, and query performance.     

面向Web服务的ERP协同集成框架研究

面向服务体系结构作为新一代分布式计算范式而成为研究企业应用集成这一领域的最新热点。但现有的工作尚未明确界定基于Web服务的ERP集成框架模型和实现机制。文章从企业分布式计算和XML技术发展融合的角度提出了一个新的基于Web服务的ERP协同集成框架。在给出Web服务形式化定义的基础上,对6层核心协议栈规范进行了扩充,定义了特定领域服务协同标识语言的基本元素,使协议规范不仅适用于Web服务,而且适用于企业内部的应用程序和应用程序内部组件的描述、发现和集成。建立了基于Web服务集成框架的支撑平台,并将该平台用于企业的整个ERP集成过程中。     

CSchema: A Downgrading Policy Language for XML Access Control

The problem of regulating access to XML documents has attracted much attention from both academic and industry communities. In existing approaches, the XML elements specified by access policies axe either accessible or inaccessible according to their sensitivity. However, in some cases, the original XML elements are sensitive and inaccessible, but after being processed in some appropriate ways, the results become insensitive and thus accessible. This paper proposes a policy language to accommodate such cases, which can express the downgrading operations on sensitive data in XML documents through explicit calculations on them. The proposed policy language is called calculation-embedded schema （CSchema）, which extends the ordinary schema languages with protection type for protecting sensitive data and specifying downgrading operations. CSchema language has a type system to guarantee the type correctness of the embedded calculation expressions and moreover this type system also generates a security view after type checking a CSchema policy. Access policies specified by CSchema are enforced by a validation procedure, which produces the released documents containing only the accessible data by validating the protected documents against CSchema policies. These released documents are then ready to be accessed by, for instance, XML query engines. By incorporating this validation procedure, other XML processing technologies can use CSchema as the access control module.