Dynamic XML Research Articles

Data hiding and security for XML database: A TRBAC-based approach

In order to cope with varying protection granularity levels of XML (eXtensible Markup Language) documents, we propose a TXAC (Two-level XML Access Control) framework, in which an extended TRBAC (Temporal Role-Based Access Control) approach is proposed to deal with the dynamic XML data. With different system components, TXAC algorithm evaluates access requests efficiently by appropriate access control policy in dynamic web environment. The method is a flexible and powerful security system offering a multi-level access control solution.

An XML query engine for network-bound data

XML has become the lingua franca for data exchange and integration across administrative and enterprise boundaries. Nearly all data providers are adding XML import or export capabilities, and standard XML Schemas and DTDs are being promoted for all types of data sharing. The ubiquity of XML has removed one of the major obstacles to integrating data from widely disparate sources - namely, the heterogeneity of data formats. However, general-purpose integration of data across the wide are a also requires a query processor that can query data sources on demand, receive streamed XML data from them, and combine and restructure the data into new XML output - while providing good performance for both batch-oriented and ad hoc, interactive queries. This is the goal of the Tukwila data integration system, the first system that focuses on network-bound, dynamic XML data sources. In contrast to previous approaches, which must read, parse, and often store entire XML objects before querying them, Tukwila can return query results even as the data is streaming into the system. Tukwila is built with a new system architecture that extends adaptive query processing and relational-engine techniques into the XML realm, as facilitated by a pair of operators that incrementally evaluate a query's input path expressions as data is read. In this paper, we describe the Tukwila architecture and its novel aspects, and we experimentally demonstrate that Tukwila provides better overall query performance and faster initial answers than existing systems, and has excellent scalability.

Static Analysis for Dynamic XML

We describe the <em>summary graph</em> lattice for dataflow analysis of programs that dynamically construct XML documents. Summary graphs have successfully been used to provide static guarantees in the JWIG language for programming interactive Web services. In particular, the JWIG compiler is able to check validity of dynamically generated XHTML documents and to type check dynamic form data. In this paper we present summary graphs and indicate their applicability for various scenarios. We also show that summary graphs have exactly the same expressive power as the regular expression types from XDuce, but that the extra structure in summary graphs makes them more suitable for certain program analyses.

XML-Based Transit Timetable System

The Internet and the World Wide Web are used for a wide variety of transportation applications. Most of these applications use static HTML documents. However, outside of transportation, considerably more attention is being given to dynamic content and XML. A way in which these technologies can be used to provide transit timetable information on the web is explored. Specifically, the transit timetable system, an online interactive transit timetable information exchange and administration system that uses Java server pages and the transit timetable markup language, is described.

Dynamic modification of XML documents

In this paper we describe a mechanism for invoking external applications from XML documents and returning the results back into the documents such that it becomes possible to create dynamic XML documents with content fetched from external resources such as remote databases or legacy applications. One possible application is to support dynamic electronic catalogs in XML where the catalog content is automatically and dynamically updated to contain the most recent data external to the document by accessing resources like legacy applications or databases each time it is parsed.The mechanism introduced involves a way of specifying applications to be invoked from an XML document through a new processing instruction, called EXECUTE. The proposed approach necessitates a "variable" mechanism to be able to pass input parameters to the invoked applications and to use the returned results. A variable mechanism is not readily available in XML therefore we have modified the code of an XML parser such that it became possible to redefine the values of XML entities and thus to use them as variables. XML-RPC from UserLand is used for remote method invocation.When it comes to integrating the returned results into the original document, as long as a single value is returned, it can be readily inserted into an XML document. However a piece of XML document may also be the result of the external application. In this case if a validating parser is being used, as in our case, then the DTD specified should be that of the final document.The paper concludes by discussing the future work.

Proportionate mortality among construction laborers : F. Stern, P. Schulte, M. H. Sweeney, M. Fingerhut, P. Vossenas, G. Burkhardt, M.-F. Kornak. American Journal of Industrial Medicine, 27(4), 485–509

With the growing importance of the semi-structure data in information exchange, there is an increasing need for querying and searching XML data. In order to find all occurrences of a twig pattern in XML documents, a considerable amount of twig pattern matching algorithms have been proposed. Those algorithms are quite efficient for queries in static documents. But for queries in dynamic documents, the previous approaches often suffer from high updating cost, which significantly decrease the query performance. To overcome this limitation, we develop an efficient method to perform twig pattern matching in dynamic XML documents in this paper. Our approach adopts a dynamic labeling scheme and supports successive queries in a dynamic environment. More importantly, depending on the dynamic labeling scheme, it completely avoids unnecessary re-labeling after updates, and significantly improves the query performance. Finally, we run extensive experiments to validate our approach and show its significant superiority.