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El autor Salvador Tamarit ha publicado 8 artículo(s):

1 - Automatic Testing of Program Slicers

Program slicing is a technique to extract the part of a program (the slice) that influences or is influenced by a set of variables at a given point (the slicing criterion). Computing minimal slices is undecidable in the general case, and obtaining the minimal slice of a given program is normally computationally prohibitive even for very small programs. Therefore, no matter what program slicer we use, in general, we cannot be sure that our slices are minimal. This is probably the fundamental reason why no benchmark collection of minimal program slices exists. In this work, we present a method to automatically produce quasi-minimal slices. Using our method, we have produced a suite of quasi-minimal slices for Erlang that we have later manually proved they are minimal. We explain the process of constructing the suite, the methodology and tools that were used, and the results obtained. The suite comes with a collection of Erlang benchmarks together with different slicing criteria and the associated minimal slices.

Autores: Sergio Pérez / Josep Sílva / Salvador Tamarit / 
Palabras Clave: Erlang - Program analysis - Program Slicing - Testing

2 - A Haskell Implementation of a Rule-Based Program Transformation for C Programs

Obtaining good performance when programming heterogeneous computing platforms poses significant challenges for the programmer. We present a program transformation environment, implemented in Haskell, where architecture-agnostic scientific C code is transformed into a functionally equivalent one better suited for a given platform. The transformation rules are formalized in a domain-specific language (STML) that takes care of the syntactic and semantic conditions required to apply a given transformation. STML rules are compiled into Haskell function definitions that operate at AST level. Program properties, to be matched with rule conditions, can be automatically inferred or, alternatively, stated as annotations in the source code. Early experimental results are described.

Autores: Salvador Tamarit / Guillermo Vigueras / Manuel Carro / Julio Mariño / 
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3 - A Declarative Debugger for Concurrent Erlang Programs

Erlang is a concurrent language with features such as actor model concurrency, no shared memory, message passing communication, high scalability and availability. However, the development of concurrent programs is a complex and error prone task. In this paper we present a declarative debugging approach for concurrent Erlang programs. Our debugger asks questions about the validity of transitions between the different points of the program that involve message passing and/or process creation. The answers, which represent the intended behavior of the program, are compared with the transitions obtained in an actual execution of the program. The differences allow us to detect program errors and to point out the pieces of source code responsible for the bugs. In order to represent the computations we present a semantic calculus for concurrent Core Erlang programs. The debugger uses the proof trees in this calculus as debugging trees used for selecting the questions asked to the user. The relation between the debugging trees and the semantic calculus allows us to establish the soundness of the approach. The theoretical ideas have been implemented in a debugger prototype.

Autores: R. Caballero / E. Martin-Martin / A. Riesco / Salvador Tamarit / 
Palabras Clave: Concurrency - Declarative Debugging - Erlang - Semantics

4 - Behaviour Preservation across Code Versions in Erlang (Trabajo ya publicado)

In any alive and non-trivial program, the source code naturally evolves along the lifecycle for many reasons such as the implementation of new functionality, the optimisation of a bottle-neck, the refactoring of an obscure function, etc. Frequently, these code changes affect various different functions and modules, so it can be difficult to know whether the correct behaviour of the previous version has been preserved in the new version. In this paper, we face this problem in the context of the Erlang language, where most developers rely on a previously defined test suite to check the behaviour preservation. We propose an alternative approach to automatically obtain a test suite that specifically focusses on comparing the old and new versions of the code. Our test case generation is directed by a sophisticated combination of several already existing tools such as TypEr, CutEr, and PropEr; and it introduces novel ideas such as allowing the programmer to choose one or more expressions of interest that must preserve the behaviour, or the recording of the sequences of values to which those expressions are evaluated. All the presented work has been implemented in an open-source tool that is publicly available on GitHub.

Autores: David Insa / Sergio Pérez Rubio / Josep Silva / Salvador Tamarit / 
Palabras Clave: Automated regression testing - Code evolution control - Tracing

5 - Site-Level Template Extraction Based on Hyperlink Analysis (Original Work)

Web templates are one of the main development resources for website engineers. Templates allow them to increase productivity by plugin content into already formatted and prepared pagelets. For the final user templates are also useful, because they provide uniformity and a common look and feel for all webpages. However, from the point of view of crawlers and indexers, templates are an important problem, because templates usually contain irrelevant information such as advertisements, menus, and banners. Processing and storing this information is likely to lead to a waste of resources (storage space, bandwidth, etc.). It has been measured that templates represent between 40% and 50% of data on the Web. Therefore, identifying templates is essential for indexing tasks. In this work we propose a novel method for automatic template extraction that is based on similarity analysis between the DOM trees of a collection of webpages that are detected using menus information. Our implementation and experiments demonstrate the usefulness of the technique.

Autores: Julián Alarte / David Insa / Josep Silva / Salvador Tamarit / 
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6 - Reversible CSP Computations

Original publication metadataPublished in: IEEE Transactions on Parallel and Distributed Systems (Volume: 32, Issue: 6, June 1 2021)Date of Publication: 14 January 2021Pages: 1425 – 1436 (12 pages)DOI: 10.1109/TPDS.2021.3051747Publisher: IEEEAbstract:Reversibility enables a program to be executed both forwards and backwards. This ability allows programmers to backtrack the execution to a previous state. This is essential if the computation is not deterministic because re-running the program forwards may not lead to that state of interest. Reversibility of sequential programs has been well studied and a strong theoretical basis exists. Contrarily, reversibility of concurrent programs is still very young, especially in the practical side. For instance, in the particular case of the Communicating Sequential Processes (CSP) language, reversibility is practically missing. In this article, we present a new technique, including its formal definition and its implementation, to reverse CSP computations. Most of the ideas presented can be directly applied to other concurrent specification languages such as Promela or CCS, but we center the discussion and the implementation on CSP. The technique proposes different forms of reversibility, including strict reversibility and causal-consistent reversibility. On the practical side, we provide an implementation of a system to reverse CSP computations that is able to highlight the source code that is being executed in each forwards/backwards computation step, and that has been optimized to be scalable to real systems.

Autores: Carlos Galindo / Naoki Nishida / Josep Silva / Salvador Tamarit / 
Palabras Clave: Causal-consistent reversibility - Code inspections and walkthroughs - Communicating sequential processes - Concurrent programming - Concurrent specification languages - Debugging aids - Strict reversibility - Synchronization - Tracing

7 - A Collection of Website Benchmarks Labelled for Template Detection and Content Extraction

Template detection and content extraction are two of the main areas of information retrieval applied to the Web. They perform different analyses over the structure and content of webpages to extract some part of the document. However, their objectives are different. While template detection identifies the template of a webpage (usually comparing with other webpages of the same website), content extraction identifies the main content of the webpage discarding the other part. Therefore, they are somehow complementary, because the main content is not part of the template. It has been measured that templates represent between 40% and 50% of data on the Web. Therefore, identifying templates is essential for indexing tasks because templates usually contain irrelevant information such as advertisements, menus and banners. Processing and storing this information is likely to lead to a waste of resources (storage space, bandwidth, etc.). Similarly, identifying the main content is essential for many information retrieval tasks. In this paper, we present a benchmark suite to test different approaches for template detection and content extraction. The suite is public, and it contains real heterogeneous webpages that have been labelled so that different techniques can be suitable (and automatically) compared.

Autores: Julián Alarte / David Insa / Josep Silva / Salvador Tamarit / 
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