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Conference Paper
The Influence of the Java Collection Framework on Overall Energy Consumption, Pereira, Rui, Couto Marco, Saraiva João, Cunha Jácome, and Fernandes João P. , 5th International Workshop on Green and Sustainable Software (ICSE 2016), 15-21, p.–, (2016) Abstractgreens.pdf

This paper presents a detailed study of the energy consumption of the different Java Collection Framework (JFC) implementations. For each method of an implementation in this framework, we present its energy consumption when handling different amounts of data. Knowing the greenest methods for each implementation, we present an energy optimization approach for Java programs: based on calls to JFC methods in the source code of a program, we select the greenest implementation. Finally, we present preliminary results of optimizing a set of Java programs where we obtained 6.2% energy savings.

MDSheet – Model-Driven Spreadsheets, Cunha, Jácome, Fernandes João Paulo, Mendes Jorge, Pereira Rui, and Saraiva João , Proceedings of the 1st Workshop on Software Engineering methods in Spreadsheets, Volume 1209, p.31–33, (2014) Abstractsems14-td.pdf

This paper showcases MDSheet, a framework aimed at improving the engineering of spreadsheets. This framework is model-driven, and has been fully integrated under a spreadsheet system. Also, its practical interest has been demonstrated by several empirical studies.

MDSheet: A Framework for Model-driven Spreadsheet Engineering, Cunha, Jácome, Fernandes João Paulo, Mendes Jorge, and Saraiva João , Proceedings of the 34rd International Conference on Software Engineering, p.1395–1398, (2012) Abstracticse12_tooldemo.pdf

n this paper, we present MDSHEET, a framework for the embedding, evolution and inference of spreadsheet models. This framework offers a model-driven software development mechanism for spreadsheet users.

Memoization for Saving Energy in Android Applications: When and how to di it, Pinto, Adriano, Couto Marco, and Cunha Jácome , (Submitted) Abstractpaper.pdf

Over the last few years, the interest in the analysis of the energy consumption of Android applications has been increasing significantly. Indeed, there are a considerable number of studies which aim at analyzing the energy consumption in various ways, such as measuring/estimating the energy consumed by an application or block of code, or even detecting energy expensive coding patterns or API's.

Nevertheless, when it comes to actually improving the energy efficiency of an application, we face a whole new challenge, which can only be achieved through source code improvements that can take advantage of energy saving techniques. However, there is still a lack of information about such techniques and their impact on energy consumption.

In this paper, we analyze the impact of the memoization technique in the energy consumption of Android applications. We present a systematic study of the use of memoization, where we compare implementations of 18 method from different applications, with and without using memoization, and measure the energy consumption of both of them. Using this approach, we are able to characterize Android methods that should be memoized.

Our results show that using memoization can clearly be a good approach for saving energy. For the 18 tested methods, 13 of them decreased significantly their energy consumption, while for the remaining 5 we observed unpredictable behavior in 3 of them and an overall increase of energy consumption in the last 2. We also included a discussion about when is actually beneficial to use memoization for saving energy, and what is the expected percentage of gain/loss when memoization works and when it does not.

Modeling the Impact of UAVs in Sustainability, Conejero, José, Brito Isabel, Moreira Ana, Cunha Jácome, and Araújo João , 5th International Workshop on Requirements Engineering for Sustainable Systems (RE4SuSy) @RE16, Beijing, China, (2016) 2016-modeling-impact.pdf
Products go Green: Worst-Case Energy Consumption in Software Product Lines, Couto, Marco, Borba Paulo, Cunha Jácome, Fernandes João P., Pereira Rui, and Saraiva João , 21st International Systems and Software Product Line Conference, Sept 25-29, Sevilla, Spain, (2017) paper.pdf
A Quality Model for Spreadsheets, Cunha, Jácome, Fernandes João Paulo, Peixoto Christophe, and Saraiva João , Proceedings of the 8th International Conference on the Quality of Information and Communications Technology, Quality in ICT Evolution Track, p.231–236, (2012) Abstractquatic2012.pdf

In this paper we present a quality model for spreadsheets, based on the ISO/IEC 9126 standard that defines a generic quality model for software. To each of the software characteristics defined in the ISO/IEC 9126, we associate an equivalent spreadsheet characteristic. Then, we propose a set of spreadsheet specific metrics to assess the quality of a spreadsheet in each of the defined characteristics. In order to obtain the normal distribution of expected values for a spreadsheet in each of the metrics that we propose, we have executed them against all spreadsheets in the large and widely used EUSES spreadsheet corpus. Then, we quantify each characteristic of our quality model after computing the values of our metrics, and we define quality scores for the different ranges of values. Finally, to automate the atribution of a quality score to a given spreadsheet, according to our quality model, we have integrated the computation of the metrics it includes in both a batch and a web-based tool.

Querying Model-Driven Spreadsheets, Cunha, Jácome, Fernandes João Paulo, Mendes Jorge, Pereira Rui, and Saraiva João , Proceedings of the 2013 IEEE Symposium on Visual Languages and Human-Centric Computing, Washington, DC, USA, p.83–86, (2013) Abstractvlhcc2013-query.pdf

Spreadsheets are being used with many different purposes that range from toy applications to complete information systems. In any of these cases, they are often used as data repositories that can grow significantly. As the amount of data grows, it also becomes more difficult to extract concrete information out of them. This paper focuses on the problem of spreadsheet querying. In particular, we propose an expressive and composable technique where intuitive queries can be defined. Our approach builds on a model-driven spreadsheet development environment, and queries are expressed referencing entities in the model of a spreadsheet instead of in its actual data. Finally, the system that we have implemented relies on Google's query function for spreadsheets.

QuerySheet: A Bidirectional Query Environment for Model-Driven Spreadsheets, Belo, Orlando, Cunha Jácome, Fernandes João Paulo, Mendes Jorge, Pereira Rui, and Saraiva João , Proceedings of the 2013 IEEE Symposium on Visual Languages and Human-Centric Computing, Washington, DC, USA, p.199–200, (2013) Abstractvlhcc2013-td.pdf

This paper presents a tool, named QUERYSHEET, to query spreadsheets. We defined a language to write the queries, which resembles SQL, the language to query databases. This allows to write queries which are more related to the spreadsheet content than with current approaches.

Refactoring meets Model-Driven Spreadsheet Evolution, Cunha, Jácome, Fernandes João Paulo, Martins Pedro, Pereira Rui, and Saraiva João , Proceedings of the 9th International Conference on the Quality of Information and Communications Technology, Quality in Model Driven Engineering Track, p.196–201, (2014) Abstractquatic14.pdf

Software refactoring is a well-known technique that provides transformations on software artifacts with the aim of improving their overall quality. In this paper we present a set of refactorings for ClassSheets, a modeling language that allows to specify the business logic of a spreadsheet in an object-oriented fashion. The set of refactorings that we propose allows us to improve the quality of these spreadsheet models. Moreover, it is implemented in a setting that guarantees that all model refactorings are automatically carried to all the corresponding (spreadsheet) instances, thus providing an automatic evolution of the data so it is always synchronized with the model.

Smelling Faults in Spreadsheets, Abreu, Rui, Cunha Jácome, Fernandes João Paulo, Martins Pedro, Perez Alexandre, and Saraiva João , Proceedings of the 30th IEEE International Conference on Software Maintenance and Evolution, Washington, DC, USA, p.111–120, (2014) Abstracticsme14.pdf

Despite being staggeringly error prone, spreadsheets are a highly flexible programming environment that is widely used in industry. In fact, spreadsheets are widely adopted for decision making, and decisions taken upon wrong (spreadsheet-based) assumptions may have serious economical impacts on businesses, among other consequences. This paper proposes a technique to automatically pinpoint potential faults in spreadsheets. It combines a catalog of spreadsheet smells that provide a first indication of a potential fault, with a generic spectrum-based fault localization strategy in order to improve (in terms of accuracy and false positive rate) on these initial results. Our technique has been implemented in a tool which helps users detecting faults. To validate the proposed technique, we consider a well-known and well-documented catalog of faulty spreadsheets. Our experiments yield two main results: we were able to distinguish between smells that can point to faulty cells from smells and those that are not capable of doing so; and we provide a technique capable of detecting a significant number of errors: two thirds of the cells labeled as faulty are in fact (documented) errors.

SmellSheet Detective: A Tool for Detecting Bad Smells in Spreadsheets, Cunha, Jácome, Fernandes João Paulo, Mendes Jorge, Martins Pedro, and Saraiva João , Proceedings of the 2012 IEEE Symposium on Visual Languages and Human-Centric Computing, Washington, DC, USA, p.243–244, (2012) Abstractvlhcc12-td.pdf

This tool demo paper presents SmellSheet Detective: a tool for automatically detecting bad smells in spreadsheets. We have defined a catalog of bad smells in spreadsheet data which was fully implemented in a reusable library for the manipulation of spreadsheets. This library is the building block of the SmellSheet Detective tool, that has been used to detect smells in large, real-world spreadsheet within the EUSES corpus, in order to validate and evolve our bad smells catalog.

Spreadsheet Engineering, Cunha, Jácome, Fernandes João Paulo, and Saraiva João , Central European Functional Programming School - 5th Summer School, CEFP 2013, Revised Selected Papers, July, Springer, Heidelberg, (2014) Abstractdsl13_notes.pdf

These tutorial notes present a methodology for spreadsheet engineering. First, we present data mining and database techniques to reason about spreadsheet data. These techniques are used to compute relationships between spreadsheet elements (cells/columns/rows). These relations are then used to infer a model defining the business logic of the spreadsheet. Such a model of a spreadsheet data is a visual domain specific language that we embed in a well-known spreadsheet system. The embedded model is the building block to define techniques for model-driven spreadsheet development, where advanced techniques are used to guarantee the model-instance synchronization. In this model-driven environment, any user data update as to follow the the model-instance conformance relation, thus, guiding spreadsheet users to introduce correct data. Data refinement techniques are used to synchronize models and instances after users update/evolve the model. These notes briefly describe our model-driven spreadsheet environment, the MDSheet environment, that implements the presented methodology. To evaluate both proposed techniques and the MDSheet tool, we have conducted, in laboratory sessions, an empirical study with the summer school participants. The results of this study are presented in these notes.

SpreadsheetDoc: An Excel Add-in for Documenting Spreadsheets, Canteiro, Diogo, and Cunha Jácome , Proceedings of the 6th National Symposium of Informatics (INForum’15), Covilhã, Portugal, (2015) inforum2015.pdf
Static Energy Consumption Analysis in Variability Systems, Couto, Marco, Cunha Jácome, Fernandes João Paulo, Pereira Rui, and Saraiva João Alexandre , 2nd Green in Software Engineering Workshop (GInSEng’16), an event of the 4th International Conference on ICT for Sustainability (ICT4S), 29 Aug. - 1 Sep., Amsterdam, The Netherlands, (2016) Abstractginseng_2016_paper_1-2.pdf

Energy consumption is becoming an evident concern to software developers. This is even more notorious due to the propagation of mobile devices. Such propagation of devices is also influencing software development: a software system is now developed has a set of similar products sharing common features.
In this short paper, we describe our methodology aim at static and accurately predict the energy consumption of software products in such variability systems, typically called software product lines.

Systematic Spreadsheet Construction Processes, Mendes, Jorge, Cunha Jácome, Duarte Francisco, Engels Gregor, Saraiva João, and Sauer Stefan , IEEE Symposium on Visual Languages and Human-Centric Computing (VL/HCC), 11-14 Oct., Raleigh, North Carolina, USA, (2017) paper.pdf
Towards a Catalog of Spreadsheet Smells, Cunha, Jácome, Fernandes João P., Ribeiro Hugo, and Saraiva João , Proceedings of the 12th International Conference on Computational Science and Its Applications - Volume Part IV, Berlin, Heidelberg, p.202–216, (2012) Abstracticcsa-sq12.pdf

Spreadsheets are considered to be the most widely used programming language in the world, and reports have shown that 90% of real-world spreadsheets contain errors. In this work, we try to identify spreadsheet smells, a concept adapted from software, which consists of a surface indication that usually corresponds to a deeper problem. Our smells have been integrated in a tool, and were computed for a large spreadsheet repository. Finally, the analysis of the results we obtained led to the refinement of our initial catalog.

Towards an Evaluation of Bidirectional Model-driven Spreadsheets, Cunha, Jácome, Fernandes João Paulo, Mendes Jorge, and Saraiva João , User evaluation for Software Engineering Researchers, p.25–28, (2012) Abstractuser12.pdf

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. In order to improve the productivity of spreadsheet end-users, the software engineering community has proposed to employ model-driven approaches to spreadsheet development. In this paper we describe the evaluation of a bidirectional model-driven spreadsheet environment. In this environment, models and data instances are kept in conformity, even after an update on any of these artifacts. We describe the issues of an empirical study we plan to conduct, based on our previous experience with end-user studies. Our goal is to assess if this model-driven spreadsheet development framework does in fact contribute to improve the productivity of spreadsheet users.

Towards Systematic Spreadsheet Construction Processes (Abstract/Poster), Mendes, Jorge, Cunha Jácome, Duarte Francisco, Engels Gregor, Saraiva João, and Sauer Stefan , Proceedings of the 39th International Conference on Software Engineering (ICSE 2017), Buenos Aires, Argentina, (2017) paper.pdfposter.pdf
Towards the Design and Implementation of Aspect-Oriented Programming for Spreadsheets, Maia, Pedro, Mendes Jorge, Cunha Jácome, Rebêlo Henrique, and Saraiva João , Proceedings of the 2nd Workshop on Software Engineering methods in Spreadsheets co-located with the 37th International Conference on Software Engineering (ICSE 2015), (2015) Abstractsems15.pdf

A spreadsheet usually starts as a simple and single- user software artifact, but, as frequent as in other software systems, quickly evolves into a complex system developed by many actors. Often, different users work on different aspects of the same spreadsheet: while a secretary may be only involved in adding plain data to the spreadsheet, an accountant may define new business rules, while an engineer may need to adapt the spreadsheet content so it can be used by other software systems. Unfortunately, spreadsheet systems do not offer modular mechanisms, and as a consequence, some of the previous tasks may be defined by adding intrusive “code” to the spreadsheet.

In this paper we go through the design and implementation of an aspect-oriented language for spreadsheets so that users can work on different aspects of a spreadsheet in a modular way. For example, aspects can be defined in order to introduce new business rules to an existing spreadsheet, or to manipulate the spreadsheet data to be ported to another system. Aspects are defined as aspect-oriented program specifications that are dynamically woven into the underlying spreadsheet by an aspect weaver. In this aspect-oriented style of spreadsheet development, different users develop, or reuse, aspects without adding intrusive code to the original spreadsheet. Such code is added/executed by the spreadsheet weaving mechanism proposed in this paper.

A Type-Level Approach to Component Prototyping, Barbosa, Luís, Cunha Jácome, and Visser Joost , International Workshop on Synthesis and Analysis of Component Connectors: in Conjunction with the 6th ESEC/FSE Joint Meeting, New York, NY, USA, p.23–36, (2007) Abstractsyanco07.pdf

Algebraic theories for modeling components and their interactions offer abstraction over the specifics of component states and interfaces. For example, such theories deal with forms of sequential composition of two components in a manner independent of the type of data stored in the states of the components, and independent of the number and types of methods offered by the interfaces of the combinators. General purpose programming languages do not offer this level of abstraction, which implies that a gap must be bridged when turning component models into implementations. In this paper, we present an approach to prototyping of component-based systems that employs so-called type-level programming (or compile-time computation) to bridge the gap between abstract component models and their type-safe implementation in a functional programming language. We demonstrate our approach using Barbosa's model of components as generalized Mealy machines. For this model, we develop a combinator library in Haskell, which uses type-level programming with two effects. Firstly, wiring between components is computed during compilation. Secondly, the well-formedness of the component compositions is guarded by Haskell's strong type system.

Type-Safe Evolution of Spreadsheets, Cunha, Jácome, Visser Joost, Alves Tiago, and Saraiva João , Proceedings of the 14th International Conference Fundamental Approaches to Software Engineering (FASE '11): Part of the Joint European Conferences on Theory and Practice of Software (ETAPS '11), Volume 6603, p.186–201, (2011) Abstractfase11.pdf

Spreadsheets are notoriously error-prone. To help avoid the introduction of errors when changing spreadsheets, models that capture the structure and interdependencies 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. We have designed an appropriate representation of spreadsheet models, including the fundamental notions of formulæand references. For these models and their instances, we have designed coupled transformation rules that cover specific spreadsheet evolution steps, such as the 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 inducing compound transformations at the instance level. This approach guarantees safe evolution of spreadsheets even when models change.

Type-Safe Evolution of Web Services, Campinhos, João, Seco João Costa, and Cunha Jácome , Proceedings of the 2nd International Workshop on Variability and Complexity in Software Design (VACE 2017), a ICSE workshop, Buenos Aires, Argentina, (2017) main.pdf
User-Friendly Spreadsheet Querying: An Empirical Study, Pereira, Rui, Saraiva João, Cunha Jácome, and Fernandes João P. , 31st Annual ACM Symposium on Applied Computing (SAC'16), Smart Human Computer Interaction Track, Poster Paper, Pisa, Italy, (2016) sac-hci16.pdf
Journal Article
Analyzing and Classifying Energy Consumption in Android Applications (in preparation), Couto, Marco, Cunha Jácome, Fernandes João P., Pereira Rui, and Saraiva João , (Submitted) paper.pdf