Debugging of Web Applications with Web-TLR

Web-TLR is a Web verification engine that is based on the well-established Rewriting Logic--Maude/LTLR tandem for Web system specification and model-checking. In Web-TLR, Web applications are expressed as rewrite theories that can be formally verified by using the Maude built-in LTLR model-checker. Whenever a property is refuted, a counterexample trace is delivered that reveals an undesired, erroneous navigation sequence. Unfortunately, the analysis (or even the simple inspection) of such counterexamples may be unfeasible because of the size and complexity of the traces under examination. In this paper, we endow Web-TLR with a new Web debugging facility that supports the efficient manipulation of counterexample traces. This facility is based on a backward trace-slicing technique for rewriting logic theories that allows the pieces of information that we are interested to be traced back through inverse rewrite sequences. The slicing process drastically simplifies the computation trace by dropping useless data that do not influence the final result. By using this facility, the Web engineer can focus on the relevant fragments of the failing application, which greatly reduces the manual debugging effort and also decreases the number of iterative verifications.Comment: In Proceedings WWV 2011, arXiv:1108.208

A rewriting logic approach to the formal specification and verification of web applications

[EN] This paper develops a Rewriting Logic framework for the automatic specification and verification of Web applications that considers the critical aspects of concurrent Web interactions, browser navigation features (e.g., forward/back-ward navigation, page refresh, and new window/tab opening), and Web script evaluation. By encompassing the main features of the most popular Web scripting languages (e.g., PHP, ASP, and Java Servlets), our scripting language is powerful enough to model the dynamics of complex Web applications, where the interactions among Web servers and Web browsers are formalized through a landmark communicating protocol that abstracts HTTP. We provide a detailed characterization of browser actions via rewrite rules and show how our models can be naturally model-checked by using the Linear Temporal Logic of Rewriting (LTLR), which is a Linear Temporal Logic that is specifically designed for model-checking rewrite theories. The framework has been completely implemented in Maude, and we report on some successful experiments that we conducted using the Maude LTLR model-checker.This work has been partially supported by the EU (FEDER) and the Spanish MEC project ref. TIN2010-21062-C02-02, and by Generalitat Valenciana ref. PROMETE02011/052. This work was carried out during the tenure by Demis Ballis of an ERCIM "Alain Bensoussan" Postdoctoral Fellowship. The research leading to these results has received funding from the European Union Seventh Framework Programme (FP7/2007-2013) under grant agreement no 246016. Daniel Romero was partially supported by FPI-MEC grant BES-2008-004860.Alpuente Frasnedo, M.; Ballis, D.; Romero, DO. (2014). A rewriting logic approach to the formal specification and verification of web applications. Science of Computer Programming. 81:79-107. https://doi.org/10.1016/j.scico.2013.07.014S791078

Rewriting-based repairing strategies for XML repositories

[EN] Keeping XML data in a consistent state w.r.t. both structure and content is a burdensome task. To maintain the consistency of ever-larger, complex XML repositories, suitable mechanisms that are able to x every possible inconsistency are needed. In this article, we present a methodology for semi-automatically repairing faulty XML repositories that can be integrated on top of an existing rewriting-based veri cation engine. As a formal basis for representing consistency criteria, we use a rule-based description formalism that is realized in the language Maude. Then, starting from a categorization of the kinds of errors that can be found during the veri cation process, we formulate a stepwise transformation procedure that achieves correctness and completeness of the XML repository w.r.t. its Maude formal speci cation while strictly observing the structure of the XML documents. With the aim of increasing the level of automation of our repair methodology, we also de ne two correction strategies and two completion strategies that reduce either the amount of information to be changed or the number of repair actions to be executed in order to deliver an XML repository that is both correct and complete. Finally, we describe a prototype implementation of the repairing tool, which we use for an experimental evaluation of our method with good results. ©2013 Elsevier Inc.All rights reserved.This work has been partially supported by the EU (FEDER) and the Spanish MEC project ref. TIN2010-21062-C02-02, and by Generalitat Valenciana ref. PROMETEO2011/052. This work was carried out during the tenure of D. Ballis’ ERCIM “Alain Bensoussan” Postdoctoral Fellowship. The research leading to these results has received funding from the European Union Seventh Framework Programme (FP7/2007–2013) under grant agreement n. 246016. F. Frechina was supported by FPU-ME grant AP2010-5681 and D. Romero by FPI-MEC grant BES-2008-004860 We would like to thank the anonymous reviewers for their helpful comments.Alpuente Frasnedo, M.; Ballis, D.; Falaschi, M.; Frechina, F.; Romero, D. (2013). Rewriting-based repairing strategies for XML repositories. The Journal of Logic and Algebraic Programming. 82(8):326-352. https://doi.org/10.1016/j.jlap.2013.05.002S32635282

Correct and Complete (Positive) Strategy Annotations for OBJ

AbstractStrategy annotations are used in several rewriting-based programming languages to introduce replacement restrictions aimed at improving efficiency and/or reducing the risk of nontermination. Unfortunately, rewriting restrictions can have a negative impact on the ability to compute normal forms. In this paper, we first ascertain/clarify the conditions ensuring correctness and completeness (regarding normalization) of computing with strategy annotations. Then, we define a program transformation methodology for (correct and) complete evaluations which applies to OBJ-like languages

Abstract Contract Synthesis and Verification in the Symbolic K Framework

[EN] In this article, we propose a symbolic technique that can be used for automatically inferring software contracts from programs that are written in a non-trivial fragment of C, called KERNELC, that supports pointer-based structures and heap manipulation. Starting from the semantic definition of KERNELC in the K semantic framework, we enrich the symbolic execution facilities recently provided by K with novel capabilities for contract synthesis that are based on abstract subsumption. Roughly speaking, we define an abstract symbolic technique that axiomatically explains the execution of any (modifier) C function by using other (observer) routines in the same program. We implemented our technique in the automated tool KINDSPEC 2.1, which generates logical axioms that express pre- and post-condition assertions which define the precise input/output behavior of the C routines. Thanks to the integrated support for symbolic execution and deductive verification provided by K, some synthesized axioms that cannot be guaranteed to be correct by construction due to abstraction can finally be verified in our setting with little effort.This work has been partially supported by the EC H2020-EU grant agreement No. 952215 (TAILOR), the EU (FEDER) and the Spanish MCIU under grant RTI2018-094403-B-C32, by Generalitat Valenciana under grant PROMETEO/2019/098.Alpuente Frasnedo, M.; Pardo, D.; Villanueva, A. (2020). Abstract Contract Synthesis and Verification in the Symbolic K Framework. Fundamenta Informaticae. 177(3-4):235-273. https://doi.org/10.3233/FI-2020-1989S2352731773-

On-demand Evaluation by Program Transformation1 1Work partially supported by CICYT TIC2001-2705-C03-01 and MCYT grants HA2001-0059 and HU2001-0019.

AbstractStrategy annotations are used in eager programming languages (e.g., OBJ2, OBJ3, CafeOBJ, and Maude) for improving efficiency and/or reducing the risk of nontermination. Syntactically, they are given either as lists of natural numbers or as lists of integers associated to function symbols whose (absolute) values refer to the arguments of the corresponding symbol. A positive index forces the evaluation of an argument whereas a negative index means “evaluation on-demand”. Recently, we have introduced a formal description of the operational meaning of such on-demand strategy annotations which improves previous formalizations that were lacking satisfactory computational properties. In this paper, we introduce an automatic, semantics-preserving program transformation which produces a program (without negative annotations) which can be then correctly executed by typical OBJ interpreters. Moreover, to demonstrate the practicality of our ideas, the program transformation has been implemented (in Haskell) and we compare the evaluation of transformed programs with the original ones on a set of representative benchmarks

LA EDUCACIÓN ARTÍSTICA COMO HERRAMIENTA DE CAMBIO SOCIAL FRENTE A LA VIOLENCIA DE GÉNERO

EXPERIENCIA ARTÍSTICA llevada a término en FLORIDA UNIVERSITÀRIA Catarroja, Valencia (ESPAÑA) durante el curso 2020/21 por el alumnado del Grado de Magisterio en Educación Primaria e Infantil en memoria de las víctimas de violencia de género (celebrado el 25 de noviembre)

La creación audiovisual en Educación Artística. Un estudio a partir de autorretratos e identidades desde la videocreación.

Esta experiencia pretende indagar acerca del lugar que ocupan las prácticas artísticas contemporáneas formadas por nuevas narrativas audiovisuales dentro de los contextos educativos. El período académico que abarca esta investigación, Educación Secundaria Obligatoria (E.S.O.) y Bachillerato, supone para los estudiantes un buen momento para hacer uso de nuevas estrategias establecidas en las artes. En esta línea, aportan nuevos conocimientos en el seno de la Educación Artística en el contexto educativo. La incorporación en la enseñanza secundaria de actividades didácticas inspiradas en el Arte Contemporáneo de índole audiovisual posibilita el desarrollo de manera crítica y reflexiva sobre aspectos relacionados con la identidad personal y colectiva del alumnado. Igualmente, plantean y desarrollan los valores culturales y sociales de nuestra sociedad. Por este motivo, estudiamos las posibilidades que ofrece la Educación Artística para fomentar nuevos discursos audiovisuales en las aulas que ayuden al alumnado en su búsqueda de identidad personal. Durante el desarrollo de esta indagación se han presentado y analizado las diferentes situaciones que relacionan la Educación Artística con el contexto educativo. A través de una metodología de investigación plural (cualitativa, cuantitativa y artística) se ha realizado un estudio para determinar el lugar que ocupa la videocreación dentro del ámbito de la Educación Artística. Además de responder a las cuestiones planteadas al inicio del proyecto, durante el proceso de investigación, se han desarrollado nuevas propuestas que configuran y ayudan a establecer la estructura de este estudio