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Publicações

Publicações por João Alexandre Saraiva

2011

End-users productivity in model-based spreadsheets: An empirical study

Autores
Beckwith, L; Cunha, J; Fernandes, JP; Saraiva, J;

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

Abstract
Spreadsheets are widely used and studies show that most of the existing ones contain non-trivial errors. To improve end-users productivity, recent research proposes the use of a model-driven engineering approach to spreadsheets. In this paper we conduct the first empirical study to assess the effectiveness and efficiency of this approach. A set of spreadsheet end users worked with two different model-based spreadsheets. We present and analyze here the results achieved. © 2011 Springer-Verlag.

2012

Model-based programming environments for spreadsheets

Autores
Cunha, J; Saraiva, J; Visser, J;

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

Abstract
Although spreadsheets can be seen as a flexible programming environment, they lack some of the concepts of regular programming languages, such as structured data types. This can lead the user to edit the spreadsheet in a wrong way and perhaps cause corrupt or redundant data. We devised a method for extraction of a relational model from a spreadsheet and the subsequent embedding of the model back into the spreadsheet to create a model-based spreadsheet programming environment. The extraction algorithm is specific for spreadsheets since it considers particularities such as layout and column arrangement. The extracted model is used to generate formulas and visual elements that are then embedded in the spreadsheet helping the user to edit data in a correct way. We present preliminary experimental results from applying our approach to a sample of spreadsheets from the EUSES Spreadsheet Corpus. © 2012 Springer-Verlag.

2011

Shortcut fusion rules for the derivation of circular and higher-order programs

Autores
Pardo, A; Fernandes, JP; Saraiva, J;

Publicação
Higher-Order and Symbolic Computation

Abstract
Functional programs often combine separate parts using intermediate data structures for communicating results. Programs so defined are modular, easier to understand and maintain, but suffer from inefficiencies due to the generation of those gluing data structures. To eliminate such redundant data structures, some program transformation techniques have been proposed. One such technique is shortcut fusion, and has been studied in the context of both pure and monadic functional programs. In this paper, we study several shortcut fusion extensions, so that, alternatively, circular or higher-order programs are derived. These extensions are also provided for effect-free programs and monadic ones. Our work results in a set of generic calculation rules, that are widely applicable, and whose correctness is formally established. © 2011 Springer Science+Business Media, LLC.

2012

Towards an evaluation of bidirectional model-driven spreadsheets

Autores
Cunha, J; Fernandes, JP; Mendes, J; Saraiva, J;

Publicação
2012 1st International Workshop on User Evaluation for Software Engineering Researchers, USER 2012 - Proceedings

Abstract
Spreadsheets are widely recognized as popular programming systems with a huge number of spreadsheets being created every day. Also, spreadsheets are often used in the decision processes of profit-oriented companies. While this illustrates their practical importance, studies have shown that up to 90% of real-world spreadsheets contain errors. © 2012 IEEE.

2003

Generating spreadsheet-like tools from strong attribute grammars

Autores
Saraiva, J; Swierstra, D;

Publicação
GENERATIVE PROGRAMMING AND COMPONENT ENGINEERING, PROCEEDINGS

Abstract
This paper presents techniques for the formal specification and efficient incremental implementation of spreadsheet-like tools. The spreadsheets are specified by strong attribute grammars. In this style of attribute grammar programming every single inductive computation is expressed within the attribute grammar formalism. Well-known attribute grammar techniques are used to reason about such grammars. For example, ordered scheduling algorithms can be used to statically guarantee termination of the attribute grammars and to derive efficient implementations. A strong attribute grammar for a spreadsheet is defined and the first incremental results are presented.

2012

From relational ClassSheets to UML+OCL

Autores
Cunha, J; Fernandes, JP; Saraiva, J;

Publicação
Proceedings of the ACM Symposium on Applied Computing

Abstract
Spreadsheets are among the most popular programming languages in the world. Unfortunately, spreadsheet systems were not tailored from scratch with modern programming language features that guarantee, as much as possible, program correctness. As a consequence, spreadsheets are populated with unacceptable amounts of errors. In other programming language settings, model-based approaches have been proposed to increase productivity and program effectiveness. Within spreadsheets, this approach has also been followed, namely by ClassSheets. In this paper, we propose an extension to ClassSheets to allow the specification of spreadsheets that can be viewed as relational databases. Moreover, we present a transformation from ClassSheet models to UML class diagrams enriched with OCL constraints. This brings to the spreadsheet realm the entire paraphernalia of model validation techniques that are available for UML. © 2012 ACM.

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