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Electronic commerce is emerging as a major Web-supported application. In this paper we argue that database technology can, and should, provide the backbone for a wide range of such applications. More precisely, we present here the ActiveViews system, which, relaying on an extensive use of database features including views, active rules (triggers), and enhanced mechanisms for notification, access control and logging/tracing of users activities, provides the needed basis for electronic commerce. Based on

In this paper, we present the W4F toolkit for the generation of wrappers for Web sources. W4F consists of a retrieval language to identify Web sources, a declarative extraction language (the HTML Extraction Language) to express robust extraction rules and a mapping interface to export the extracted information into some userde ned data-structures. To assist the user and make the creation of wrappers rapid and easy, the toolkit o ers some wysiwyg support via some wizards. Together, they permit the fast and semi-automatic generation of ready-to-go wrappers provided as Java classes. W4F has been successfully used to generate wrappers for database systems and software agents, making the content of Web sources easily accessible to any kind of application. Keywords: Web wrapper, information extraction, HTML parsing, HTML to XML conversion.

Sources of XML documents are proliferating on the Web and documents are more and more frequently exchanged among sources. At the same time, there is an increasing need of exploiting database tools to manage this kind of data. An important novelty of XML is that information on document structures is available on the Web together with the document contents. This information can be used to improve document handling and to achieve more effective and efficient searches on documents. However, in such an heterogeneous environment as the Web, it is not reasonable to assume that XML documents that enter a source always conform to a predefined DTD present in the source.

The design objective of the User Interface Markup Language (UIML) is to provide a vendorneutral, canonical representation of any user interface (UI) suitable for mapping to existing languages. UIML provides a highly device-independent method to describe a user interface. UIML factors any user interface description into six orthogonal pieces, answering six questions: 1. What are the parts comprising the UI? 2. What is the presentation (look/feel/sound) used for the parts? 3. What is the content (e.g., text, images, sounds) used in the UI? 4. What is the behavior of the UI (e.g., when someone clicks or says something)? 5. What is the mapping of the parts to UI controls in some toolkit (e.g., Java Swing classes or HTML tags)? 6. What is the API of the business logic that the UI is connected to? UIML is a meta-language, which is augmented by a vocabulary of user interface parts, properties, and events defined outside this specification. In this way, UIML is independent of user interface metaphors (e.g., “graphical user interface”, “dialogs”). UIML version 3 is a refinement of the previous versions of UIML, which were developed starting

The Web has become a major conduit to information repositories of all kinds. Web caches are employed to store a web view to provide an immediate response to recurring queries. However, the accuracy of the replicates in web caches encounters challenges due to the dynamicity of web data. We are thus developing and evaluating a web caching system equipped with an efficient refresh strategy. With the assistance of a novel index structure, the Aggregation Path Index (APIX), we built Argos, a web cache system based on the GMD XQL query engine. Argos achieves a high degree of self-maintenance by diagnosing irrelevant data update cases and hence greatly improves the refresh performance of the materialized web view. We also report preliminary experimental results assessing the performance of Argos compared to from scratch evaluation. 1. INTRODUCTION The advent of the web has dramatically increased the proliferation of information of all kinds. XML [17] is rapidly becoming popular for represen...

This technical report describes the XML data integration framework being built within the AutoMed heterogeneous data integration system. It presents a description of the overall framework, as well as an overview of and comparison with related work and solutions by other researchers. The contributions of this research are the development of two algorithms for XML data integration, the first for schema integration and the second for view materialization, both based on graph restructuring.

. With the emergence of the Internet, collaborative computing has become more feasible than ever. Organizations can share valuable information among each other. However, certain users should only access certain portions of source data. The CHAOS (Configurable Heterogeneous Active Object System) project addresses security issues that arise when information is shared among collaborating enterprises. It provides a framework for integrating security policy specification with source data maintenance. In CHAOS, security policies are incorporated into the data objects as active nodes to form active objects. When active objects are queried, their active nodes are dynamically loaded by the active security mediator and executed. The active nodes, based on the security policy incorporated, can locate and operate on all the elements within the active object, modifying the content as well as the structure of the object. A set of API's is provided to construct more complex security poli...

This paper presents a pattern language covering common techniques in this area, as well as technology projections and known uses. The target audience of this paper are developers who want to develop new solution or modify an existing solution in one of the named software engineering areas, as well as developers who want to gain a deeper understanding of the internal workings of the software engineering tools and frameworks they use

otice and the title of the publication and its date appear, and notice is given that copying is by permission of the Very Large Data Base Endowment. To copy otherwise, or to republish, requires a fee and/or special permission from the Endowment. Proceedings of the 25th VLDB Conference, Edinburgh, Scotland, 1999. technologies (Java, RMI). The prime motivations for building on the emerging XML technology are that XML will be a standard for exchanging semi-/structured information over the Internet and will be supported by many software components in form of compilers, import/export filters, query interfaces and sophisticated editors and browsers. Besides the usage of an XML repository, the ActiveView system integrates a number of other modern database technology: XML Views: Typically, in electronic commerce application there exists di#erent kinds of users who access data with di#erent points of view depending on their access rights and on the nature of