A Language for Verification and Manipulation of Web Documents

1998

Imperative programming has largely dominated both aspects ofWeb programming: adding sophisticated interactive behaviours to the Web and constructing programswhich interact with theWeb. Mostmobile code languages such as Java are based on the imperative programming paradigm. Imperative languages are widely used for building Web browsers and information gathering tools. The focus of much programming language research has been on raising the level of abstraction. Logic programming languages, which view computation as deduction from a set of axioms, is at a higher level of abstraction than imperative programming languages enabling a problem or subject domain to be modelled without focusing on the computer’s VonNeumann architecture. Logic programming with program structuring abstractions has shown its utility in a variety of applications including expert systems, Artificial Intelligence problem solving, and deductive databases. Implementations of logic programming such as Prolog have feat...

Lecture Notes in Computer Science, 2017

This paper gives a short overview of specific logical approaches to data extraction, data management, and reasoning about data. In particular, we survey theoretical results and formalisms that have been obtained and used in the context of the Lixto Project at TU Wien, the DIADEM project at the University of Oxford, and the VADA project, which is currently being carried out jointly by the universities of Edinburgh, Manchester, and Oxford. We start with a formal approach to web data extraction rooted in monadic second order logic and monadic Datalog, that gave rise to the Lixto data extraction system. We then present some complexity results for monadic Datalog over trees and for XPath query evaluation. We further argue that for value-creation and for ontological reasoning over data, we need existential quantifiers (or Skolem terms) in rule heads, and introduce the Datalog ± family. We give an overview of important members of this family and discuss related complexity issues.

Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics), 2010

We illustrate the potential of conditional hedge transformations in Web-related applications on the example of PρLog: an extension of logic programming with advanced rule-based programming features for hedge transformations, strategies, and regular constraints.

Computer Science and Information Systems, 2009

This paper presents a solution to bridging the abstract and concrete syntax of a Web rule languages by using model transformations. Current specifications of Web rule languages such as Semantic Web Rule Language (SWRL) or RuleML define their abstract syntax (e.g., metamodel) and concrete syntax (e.g., XML schema) separately. Although the recent research in the area of Model-Driven Engineering (MDE) demonstrates that such a separation of two types of syntax is a good practice (due to the complexity of languages), one should also have tools that check validity of rules written in a concrete syntax with respect to the abstract syntax of the rule language. In this study, we use the REWERSE I1 Rule Markup Language (R2ML), SWRL, and Object Constraint Language (OCL), whose abstract syntax is defined by using metamodeling, while their textual concrete syntax is defined by using either XML/RDF schema or Extended Backus-Naur Form (EBNF) syntax. We bridge this gap by a bi-directional transformation defined in a model transformation language (ATLAS Transformation Language, ATL). This transformation allowed us to discover a number of issues in both web rule language metamodels and their corresponding concrete syntax, and thus make them fully compatible. This solution also enables for sharing web rules between different web rule languages. . His current research interests are in the area of semantic tech-nologies, software language engineering and ser-vice oriented architectures. He can be reached at http://Gerd Wagner is a Professor of Internet Technolo-gy at the Brandenburg University of Technology at Cottbus, Germany. His research interests in-clude agent-oriented modeling and agent-based simulation, foundational ontologies, (business) rule technologies and the Semantic Web. He can be reached at http://www.informatik.tu-cottbus.de/~gwagner/.

A Journey in the Computational Logic in …

Lecture Notes in Computer Science, 1997

In this paper, we address the issue of representing and reasoning about documents for which an explicit structure is provided. Specifically, we devise a framework where Document Type Definitions (DTDs) expressed in the Standard Generalized Markup Language (SGML) are formalized in an expressive Description Logic equipped with sound, complete, and terminating inference procedures. In this way, we provide a general reasoning mechanism that enables various reasoning tasks on DTDs, including the verification of typical forms of ...

2005

Xcerpt [1, 2] is a declarative and pattern-based query and transformation language for the Web with deductive capabilities. In contrast to Web query languages like XQuery and XSLT [3, 4], Xcerpt relies on concepts and techniques from logic programming and automated theorem proving such as declarative “query patterns” and “rule chaining”. Xcerpt can also be used for querying Web metadata, like OWL or RDF data [5, 6], and reasoning on such metadata.

2008 Eighth International Conference on Web Engineering, 2008

Quality assurance of Web applications is usually an informal process. Meanwhile, formal methods have been proven to be reliable means for the specification, verification, and testing of systems. However, the use of these methods requires learning their mathematical foundations, including temporal logics. Specifying properties using temporal logic is often complicated even to experts, while it is a daunting and error prone task for non-expert users. To assist web developers and testers in formally specifying web related properties, we elaborate a library of web specification patterns. The current version of the library of 119 functional and non-functional patterns is a result of scrutinizing various resources in the field of quality assurance of Web Applications, which characterize successful web application using a set of standardized attributes.

Proceedings of the ACM …, 2008

The W3C Document Object Model (DOM) specifies an XML update library. DOM is written in English, and is therefore not compositional and not complete. We provide a first step towards a compositional specification of DOM. Unlike DOM, we are able to work with a minimal set of commands and obtain a complete reasoning for straight-line code. Our work transfers O'Hearn, Reynolds and Yang's local Hoare reasoning for analysing heaps to XML, viewing XML as an in-place memory store as does DOM. In particular, we apply recent work by Calcagno, Gardner and Zarfaty on local Hoare reasoning about a simple tree-update language to DOM, showing that our reasoning scales to DOM. Our reasoning not only formally specifies a significant subset of DOM Core Level 1, but can also be used to verify e.g. invariant properties of simple Javascript programs.

IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems, 2000

Modern assertion languages such as property specification language (PSL) and SystemVerilog assertions include many language constructs. By far, the most economical way to process the full languages in automated tools is to rewrite the majority of operators to a small set of base cases, which are then processed in an efficient way. Since recent rewrite attempts in the literature have shown that the rules could be quite involved, sometimes counterintuitive, and that they can make a significant difference in the complexity of interpreting assertions, ensuring that the rewrite rules are correct is a major contribution toward ensuring that the tools are correct, and even that the semantics of the assertion languages are well founded. This paper outlines the methodology for computer-assisted proofs of several publicly known rewrite rules for PSL properties. We first present the ways to express the PSL syntax and semantics in the prototype verification system (PVS) theorem prover, and then prove or disprove the correctness of over 50 rewrite rules published without proofs in various sources in the literature. In doing so, we also demonstrate how to circumvent known issues with PSL semantics regarding the never and eventually! operators, and offer our proposals on assertion language semantics.