806 research outputs found
State-of-the-art on evolution and reactivity
This report starts by, in Chapter 1, outlining aspects of querying and updating resources on
the Web and on the Semantic Web, including the development of query and update languages
to be carried out within the Rewerse project.
From this outline, it becomes clear that several existing research areas and topics are of
interest for this work in Rewerse. In the remainder of this report we further present state of
the art surveys in a selection of such areas and topics. More precisely: in Chapter 2 we give
an overview of logics for reasoning about state change and updates; Chapter 3 is devoted to briefly describing existing update languages for the Web, and also for updating logic programs;
in Chapter 4 event-condition-action rules, both in the context of active database systems and
in the context of semistructured data, are surveyed; in Chapter 5 we give an overview of some relevant rule-based agents frameworks
Poster Presentation: Xcerpt and XChange – Logic Programming Languages for Querying and Evolution on the Web
age Xcerpt and provides advanced, Web-specific capabilities, such as propagation of changes on the Web (change) and event-based communications between Web sites (exchange). Xcerpt: Querying Data on the Web Xcerpt is a declarative, rule-based query language for Web data (i.e. XML documents or semistructured databases) based on logic programming. An Xcerpt program contains at least one goal and some (maybe zero) rules. Rules and goals consist of query and construction patterns, called terms in analogy to other logic programming languages. Terms represent tree-like (or graph-like) structures. The children of a node may be either ordered (as in standard XML) or unordered (as is common in databases). Data terms are used to represent XML documents and the data items of a semistructured database. They are similar to ground functional programming expressions and logical atoms. A database is a (multi-)set of data terms (e.g. the Web). Query terms are patterns matched against Web resources
Web and Semantic Web Query Languages
A number of techniques have been developed to facilitate
powerful data retrieval on the Web and Semantic Web. Three categories
of Web query languages can be distinguished, according to the format
of the data they can retrieve: XML, RDF and Topic Maps. This article
introduces the spectrum of languages falling into these categories
and summarises their salient aspects. The languages are introduced using
common sample data and query types. Key aspects of the query
languages considered are stressed in a conclusion
Before-Commit Client State Management Services for AJAX Applications
Heavily script-based browser applications change the manner in which users interact with Web browsers. Instead of downloading a succession of HTML pages, users download a single application and use that application for a long period of time. The application is not a set of HTML pages, but rather a single page that can possible modify its own presentation based on data exchanged with a server. In such an environment, it is necessary to provide some means for the client to manage its own state. We describe the initial results of our work in providing client-side state management services for these script-based applications. We focus on browser-based services that can help the user before any data is committed on the server. Our services include state checkpointing, property binding, operation logging, operational replay, ATOM/RSS data updates, and application-controlled persistence
Hybrid applications over XML - integrating the declarative and navigational approaches
We discuss the design of a quasi-statically typed language for XML in which data may be associated with different structures and different algebras in different scopes, whilst preserving identity. In declarative scopes, data are trees and may be queried with the full flexibility associated with XML query algebras. In procedural scopes, data have more conventional structures, such as records and sets, and can be manipulated with the constructs normally found in mainstream languages. For its original form of structural polymorphism, the language offers integrated support for the development of hybrid applications over XML, where data change form to re flct programming expectations and enable their enforcement
Survey over Existing Query and Transformation Languages
A widely acknowledged obstacle for realizing the vision of the Semantic Web is the inability
of many current Semantic Web approaches to cope with data available in such diverging
representation formalisms as XML, RDF, or Topic Maps. A common query language is the first
step to allow transparent access to data in any of these formats. To further the understanding
of the requirements and approaches proposed for query languages in the conventional as well
as the Semantic Web, this report surveys a large number of query languages for accessing
XML, RDF, or Topic Maps. This is the first systematic survey to consider query languages from
all these areas. From the detailed survey of these query languages, a common classification
scheme is derived that is useful for understanding and differentiating languages within and
among all three areas
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