Web Sites Verification: An Abductive Logic Programming Tool

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...

Electronic Notes in Theoretical Computer Science, 2009

We present a methodology and a tool for suggesting repairs to web sites that violate some given requirements in the form of web rules expressed in (an extension of) a fragment of Excerpt. The methodology consists in translating these web rules into abductive logic programs with constraints and process these by means of an existing general-purpose proof procedure, called CIFF. The tool, that we call CIFFWEB, consists of CIFF as well as the translation from rules to programs and from web sites to a suitable logical format. The tool extends an existing tool for simply checking web sites against web rules.

2009

WWV'09 provided a common forum for researchers from the communities of Rule-based programming, Automated Software Engineering, and Web-oriented research, in order to facilitate the cross-fertilization and the advancement of hybrid methods that combine the three areas. The Program Committee of WWV'09 collected three reviews for each paper and held an electronic discussion during April 2009 which has led to the selection of 10 regular papers. In addition to the selected papers, the scientific program included two invited lectures by François Bry from the Ludwig Maximilian University of Munich (Germany), and Axel Polleres from the National University of Ireland, Galway (Ireland). We would like to thank them for having accepted our invitation. We would also like to thank all the members of the Program Committee and all the referees for their careful work in the review and selection process. Many thanks to all authors who submitted papers and to all conference participants. We gratefully acknowledge all the institutions and corporations who have supported this event.

Despite the popularity of the World Wide Web as a development platform, a proper description of its architectural principles and design criteria has been established only in the last decade, by the introduction of the REpresentational State Transfer (REST) architectural style, which defines the resource as the key abstraction of information. Languages and tools used for Web programming generally suffer from a lack of proper understanding of its architecture and design constraints, and from an abstraction mismatch that makes it hard to fully exploit the Web potential. Declarative languages are well-suited for a programming system aimed at being respectful of the Web architecture and principles. Among logic technologies, tuProlog has been explicitly designed to be one of the enabling components of Internet-based infrastructures: its engineering properties make it suitable for use on the Web, where logic programming allows modification of resource behaviour at runtime. Accordingly, in this paper we present a Prolog-based logic model for programming Web resources, and outline a framework for developing Web applications grounded on that model.

2007

In this paper, we present the rewriting-based, Web verification service WebVerdi-M, which is able to recognize forbidden/incorrect patterns and incomplete/missing Web pages. WebVerdi-M relies on a powerful Web verification engine that is written in Maude, which automatically derives the error symptoms. Thanks to the AC pattern matching supported by Maude and its metalevel facilities, WebVerdi-M enjoys much better performance and usability than a previous implementation of the verification framework. By using the XML Benchmarking tool xmlgen, we develop some scalable experiments which demonstrate the usefulness of our approach.

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.

Lecture Notes in Computer Science, 2005

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 [2,3], 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 [4,5], and reasoning on such metadata. In contrast to specific languages for OWL and RDF, however, Xcerpt is a general purpose query, transformation, and reasoning language, i.e. it can be used for reasoning not only with Web metadata but also with plain Web data. Salient aspects of Xcerpt are its nonstandard "query patterns" for retrieving incompletely specified data and its unusual "grouping constructs" some and all that significantly depart from the standard approaches in logic programming or automated theorem proving. Xcerpt relies on a new, assymmetric unification, called simulation unification for evaluating query patterns that incompletely specify data. Furthermore, Xcerpt does not rely on meta reasoning for expressing and processing "grouping" constructs corresponding to Prolog's metalevel predicates setof and bagof. This article gives a brief overview over challenges of applying logic programming techniques to Web querying. In particular it suggests two different approaches for treating the meta-level grouping constructs all and some in a proof calculus formalising the operational semantics of Xcerpt.

2004

Defeasible reasoning is a rule-based approach for efficient reasoning with incomplete and inconsistent information. Such reasoning is, among others, useful for ontology integration, where conflicting information arises naturally; and for the modeling of business rules and policies, where rules with exceptions are often used. This paper describes these scenarios in more detail, and reports on the implementation of a system for defeasible reasoning on the Web. The system (a) is syntactically compatible with RuleML; (b) features strict and defeasible rules and priorities; (c) is based on a translation to logic programming with declarative semantics; and (d) is flexible and adaptable to different intuitions within defeasible reasoning.

In this note we retrospect on the ve years of the Web Reasoning and Rule Systems conference series and discuss the rationale for the series in the context of the overall eld of the Semantic Web, the activities of the Web Reasoning research community, and the development of standards for rule-based systems on the Web. At the end, we draw the reader's attention to the next event in the series, which will take place in Vienna in September 2012.

Springer eBooks, 2001

Web design is an inherently error-prone process. To help with the detection of errors in the structure and connectivity of Web pages, we propose to apply model-checking techniques to the analysis of the World Wide Web. Model checking the Web is different in many respects from ordinary model checking of system models, since the Kripke structure of the Web is not known in advance, but can only be explored in a gradual fashion. In particular, the model-checking algorithms cannot be phrased in ordinary µ-calculus, since some operations, such as the computation of sets of predecessor Web pages and the computations of greatest fixpoints, are not possible on the Web. We introduce constructive µ-calculus, a fixpoint calculus similar to µ-calculus, but whose formulas can be effectively evaluated over the Web; and we show that its expressive power is very close to that of ordinary µ-calculus. Constructive µ-calculus can be used not only for phrasing Web model-checking algorithms, but also for the analysis of systems having a large, irregular state space that can be only gradually explored, such as software systems. On the basis of these ideas, we have implemented the Web model checker MCWEB, and we describe some of the issues that arose in its implementation, as well as the type of errors that it was able to find.