Publications

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Journal Article
Embedding, Evolution, and Validation of Spreadsheet Models in Spreadsheet Systems, Cunha, Jácome, Fernandes João P., Mendes Jorge, and Saraiva João , IEEE Transactions on Software Engineering, Volume 41, Issue 3, p.241-263, (2014) Abstracttse14.pdfWebsite

This paper proposes and validates a model-driven software engineering technique for spreadsheets. The technique that we envision builds on the embedding of spreadsheet models under a widely used spreadsheet system. This means that we enable the creation and evolution of spreadsheet models under a spreadsheet system. More precisely, we embed ClassSheets, a visual language with a syntax similar to the one offered by common spreadsheets, that was created with the aim of specifying spreadsheets. Our embedding allows models and their conforming instances to be developed under the same environment. In practice, this convenient environment enhances evolution steps at the model level while the corresponding instance is automatically co-evolved. Finally, we have designed and conducted an empirical study with human users in order to assess our technique in production environments. The results of this study are promising and suggest that productivity gains are realizable under our model-driven spreadsheet development setting.

Evaluating Refactorings for Spreadsheet Models, Cunha, Jácome, Fernandes João Paulo, Mendes Jorge, Pereira Rui, Saraiva João Alexandre, and Martins Pedro , Journal of Systems and Software, Volume 118, p.234-250, (2016) Abstractmain.pdf

Software refactoring is a well-known technique that provides transformations on software artifacts with the aim of improving their overall quality.

In the past, we have proposed a catalog of refactoring for spreadsheet models expressed in the ClassSheets modeling language, which allows us to specify the business logic of a spreadsheet in an object-oriented fashion.

Reasoning about spreadsheets at the model level enhances a model-driven spreadsheet environment where a ClassSheet model and its conforming instance (the spreadsheet data) automatically co-evolves after a refactoring is applied at the model level. Our motivation for such research was to improve the model and its conforming instance: the spreadsheet data.

In this paper we define such refactorings using previously proposed evolution steps for models and instances.

We also present an empirical study we designed and conducted in order to confirm our original intuition that these refactorings have a positive impact on end-user productivity, both in terms of effectiveness and efficiency.

The results are presented not only in terms of productivity changes between refactored and non-refactored scenarios, but also in terms of overall user satisfaction, relevance, and experience.

In almost all cases the refactorings indeed improved end-users productivity. Moreover, in most cases users were more engaged with the refactored version of the spreadsheets they worked with.

Model-Based Programming Environments for Spreadsheets, Cunha, Jácome, Mendes Jorge, Saraiva João, and Visser Joost , Journal of Science of Computer Programming (SCP), Volume 96, p.254–275, (2014) Abstractscp14.pdfWebsite

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A Structured Approach to Document Spreadsheets (in preparation), Cunha, Jácome, and Canteiro Diogo , (Submitted) jvlc.pdf
Miscellaneous
Embedding, Evolution, and Validation of Spreadsheet Models in Spreadsheet Systems, Cunha, Jácome, Fernandes João P., Mendes Jorge, and Saraiva João , Number TR-HASLab:01:2014, (2014) Abstracttr_embedding.pdf

This paper proposes and validates a model-driven software engineering technique for spreadsheets. The technique that we envision builds on the embedding of spreadsheet models under a widely used spreadsheet system, so that models and their conforming instances are developed under the same environment. In practice, this convenient environment enhances evolution steps at the model level while the corresponding instance is automatically co-evolved. Finally, we have designed and conducted an empirical study with human users in order to assess our technique in production environments. The results of this study are promising and suggest that productivity gains are realizable under our model-driven spreadsheet development setting.

End Users Productivity in Model-based Spreadsheets: An Empirical Study, Beckwith, Laura, Cunha Jácome, Fernandes João Paulo, and Saraiva João , Number DI-CCTC-10-10, (2010) Abstracttr_study.pdf

Spreadsheets are widely used by end users, and studies have shown that most end-user spreadsheets 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 systematic empirical study to assess the effectiveness and efficiency of this approach. A set of spreadsheet end users worked with two different model-based spreadsheets, and we present and analyze the results achieved.

Evolução Controlada de Arquitecturas de Serviços Web, Campinhos, João, Seco João Costa, and Cunha Jácome , (2016) poster6.1.pdfmain.pdf
SSaaPP: SpreadSheets as a Programming Paradigm – Project's Final Report, Abreu, Rui, Alves Tiago, Belo Orlando, Campos José C., Cunha Jácome, Fernandes João Paulo, Martins Pedro, Mendes Jorge, Pacheco Hugo, Peixoto Christophe, Pereira Rui, Perez Alexandre, Ribeiro Hugo, Riboira André, Saraiva João, Silva André, Silva João Carlos, and Visser Joost , Number TR-HASLab:02:2014, (2014) Abstracttr_ssaapp.pdf

This technical report describes the research goals and results of the SpreadSheet as a Programming Paradigm research project. This was a project funded by Funda{\c c}ão para a Ciencia e Tecnologia – FCT: the Portuguese research foundation, under reference FCOMP-01-0124-FEDER-010048, that ran from May 2010 till July 2013. This report includes the complete document reporting the results achieved during the project execution, which was submitted to FCT for evaluation on October 2013. It describes the goals of the project, and the different research tasks presenting the deliver- ables of each of them. It also presents the management and result dissemination work performed during the project's execution. The document includes also a self assess- ment of the achieved results, and a complete list of scientific publications describing the contributions of the project. Finally, this document includes the FCT evaluation report.

Type-Safe Evolution of Spreadsheets, Cunha, Jácome, Visser Joost, Alves Tiago, and Saraiva João , Number DI-CCTC-10-09, (2010) Abstracttr_evolution.pdf

Spreadsheets are notoriously error-prone. To help avoid the introduction of errors when changing spreadsheets, models that capture the structure and inter-dependencies of spreadsheets at a conceptual level have been proposed. Thus, spreadsheet evolution can be made safe within the confines of a model. As in any other model/instance setting, evolution may not only require changes at the instance level but also at the model level. When model changes are required, the safety of instance evolution can not be guarded by the model alone. Coupled transformation of models and instances are supported by the 2LT platform and have been applied for transformation of algebraic datatypes, XML schemas, and relational database models. We have extended 2LT to spreadsheet evolution. We have designed an appropriate representation of spreadsheet models, including the fundamental notions of formulæ, references, and blocks of cells. For these models and their instances, we have designed coupled transformation rules that cover specific spreadsheet evolution steps, such as extraction of a block of cells into a separate sheet or insertion of columns in all occurrences of a repeated block of cells. Each model-level transformation rule is coupled with instance level migration rules from the source to the target model and vice versa. These coupled rules can be composed to create compound transformations at the model level that induce compound transformations at the instance level. With this approach, spreadsheet evolution can be made safe, even when model changes are involved.

Thesis
Model-Based Spreadsheet Engineering, Cunha, Jácome , March, (2011) Abstractthesis.pdf

Spreadsheets can be viewed as programming languages for non-professional programmers. These so-called ``end-user'' programmers vastly outnumber professional programmers creating millions of new spreadsheets every year. As a programming language, spreadsheets lack support for abstraction, testing, encapsulation, or structured programming. As a result, and as numerous studies have shown, the high rate of production is accompanied by an alarming high rate of errors. Some studies report that up to 90% of real-world spreadsheets contain errors. After their initial creation, many spreadsheets turn out to be used for storing and processing increasing amounts of data and supporting increasing numbers of users over long periods of time, making them complicated systems. An emerging solution to handle the complex and evolving software systems is Model-driven Engineering (MDE). To consider models as first class entities and any software artifact as a model or a model element is one of the basic principles of MDE. We adopted some techniques from MDE to solve spreadsheet problems. Most spreadsheets (if not all) lack a proper specification or a model. Using reverse engineering techniques we are able to derive various models from legacy spreadsheets. We use functional dependencies (a formalism that allow us to define how some column values depend on other column values) as building blocks for these models. Models can be used for several spreadsheet improvements, namely refactoring, safe evolution, migration or even generation of edit assistance. The techniques presented in this work are available under the framework HAEXCEL that we developed. It is composed of online and batch tools, reusable HASKELL libraries and OpenOffice.org extensions. A study with several end-users was organized to survey the impact of the techniques we designed. The results of this study indicate that the models can bring great benefits to spreadsheet engineering helping users to commit less errors and to work faster.