Export 51 results:
Sort by: [ Author  (Desc)] Title Type Year
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z 
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.

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
Energy Efficiency across Programming Languages: How Do Energy, Time, and Memory Relate?, Pereira, Rui, Couto Marco, Ribeiro Francisco, Rua Rui, Cunha Jácome, Fernandes João P., and Saraiva João , 10th ACM SIGPLAN International Conference on Software Language Engineering (SLE’17), 23-24 October, Vancouver, Canada, (2017) paper.pdf
Helping Programmers Improve the Energy Efficiency of Source Code (Abstract/Poster), Pereira, Rui, Carção Tiago, Couto Marco, Cunha Jácome, Fernandes João P., and Saraiva João , Proceedings of the 39th International Conference on Software Engineering (ICSE 2017), Buenos Aires, Argentina, (2017) paper.pdfpostera3.pdf
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.

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 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
Watch out for that tree! A Tutorial on Shortcut Deforestation, Fernandes, João P., Cunha Jácome, Pardo Alberto, and Saraiva João , 2015 Central European Functional Programming School, Revised Selected Papers, (2016) cefp15.pdf
Extension and Implementation of ClassSheet Models, Cunha, Jácome, Fernandes João Paulo, Mendes Jorge, and Saraiva João , Proceedings of the 2012 IEEE Symposium on Visual Languages and Human-Centric Computing, Washington, DC, USA, p.19–22, (2012) Abstractvlhcc12.pdf

n this paper we explore the use of models in the context of spreadsheet engineering. We review a successful spreadsheet modeling language, whose semantics we further extend. With this extension we bring spreadsheet models closer to the business models of spreadsheets themselves. An addon for a widely used spreadsheet system, providing bidirectional model-driven spreadsheet development, was also improved to include the proposed model extension.

Automatically Inferring Models from Spreadsheets, Cunha, Jácome, Erwig Martin, Mendes Jorge, and Saraiva João , Automated Software Engineering (ASE), Volume 23, Issue 3, p.361-392, (2016) Abstractase14.pdfWebsite

Many errors in spreadsheet formulas can be avoided if spreadsheets are built automatically from higher-level models that can encode and enforce consistency constraints in the generated spreadsheets. Employing this strategy for legacy spreadsheets is difficult, because the model has to be reverse engineered from an existing spreadsheet and existing data must be transferred into the new model-generated spreadsheet. We have developed and implemented a technique that automatically infers relational schemas from spreadsheets. This technique uses particularities from the spreadsheet realm to create better schemas. We have evaluated this technique in two ways: First, we have demonstrated its applicability by using it on a set of real-world spreadsheets. Second, we have run an empirical study with users. The study has shown that the results produced by our technique are comparable to the ones developed by experts starting from the same (legacy) spreadsheet data. Although relational schemas are very useful to model data, they do not fit well spreadsheets as they do not allow to express layout. Thus, we have also introduced a mapping between relational schemas and ClassSheets. A ClassSheet controls further changes to the spreadsheet and safeguards it against a large class of formula errors. The developed tool is a contribution to spreadsheet (reverse) engineering, because it fills an important gap and allows a promising design method (ClassSheets) to be applied to a huge collection of legacy spreadsheets with minimal effort.

Discovery-Based Edit Assistance for Spreadsheets, Cunha, Jácome, Saraiva João, and Visser Joost , Proceedings of the 2009 IEEE Symposium on Visual Languages and Human-Centric Computing (VL/HCC), Washington, DC, USA, p.233–237, (2009) Abstractvl-hcc09.pdf

Spreadsheets can be viewed as a highly flexible end-users programming environment which enjoys wide-spread adoption. But spreadsheets lack many of the structured programming concepts of regular programming paradigms. In particular, the lack of data structures in spreadsheets may lead spreadsheet users to cause redundancy, loss, or corruption of data during edit actions. In this paper, we demonstrate how implicit structural properties of spreadsheet data can be exploited to offer edit assistance to spreadsheet users. Our approach is based on the discovery of functional dependencies among data items which allow automatic reconstruction of a relational database schema. From this schema, new formulas and visual objects are embedded into the spreadsheet to offer features for auto-completion, guarded deletion, and controlled insertion. Schema discovery and spreadsheet enhancement are carried out automatically in the background and do not disturb normal user experience.

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.

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.

ES-SQL: Visually Querying Spreadsheets, Cunha, Jácome, Fernandes João Paulo, Mendes Jorge, Pereira Rui, and Saraiva João , Proceedings of the 2014 IEEE Symposium on Visual Languages and Human-Centric Computing, Washington, DC, USA, p.203–204, (2014) Abstractvlhcc14-td.pdf

This paper presents ES-SQL, an embedded tool for visually constructing queries over spreadsheets. This tool provides an expressive query environment which has knowledge on the business logic of spreadsheets, and by this knowledge it assists the user in defining the intended queries.

A Structured Approach to Document Spreadsheets (in preparation), Cunha, Jácome, and Canteiro Diogo , (Submitted) jvlc.pdf
A Bidirectional Model-driven Spreadsheet Environment (Poster/Abstract), Cunha, Jácome, Fernandes João Paulo, Mendes Jorge, and Saraiva João , Proceedings of the 34rd International Conference on Software Engineering, p.1443–1444, (2012) Abstractabstract.pdfposter.pdf

n this extended abstract we present a bidirectional model-driven framework to develop spreadsheets. By being model driven, our approach allows to evolve a spreadsheet model and automatically have the data co-evolved. The bidirectional component achieves precisely the inverse, that is, to evolve the data and automatically obtain a new model to which the data conforms.

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.

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.

Embedding and Evolution of Spreadsheet Models in Spreadsheet Systems, Cunha, Jácome, Fernandes João Paulo, Mendes Jorge, and Saraiva João , Proceedings of the 2011 IEEE Symposium on Visual Languages and Human-Centric Computing, Washington, DC, USA, p.186–201, (2011) Abstractvlhcc11.pdf

This paper describes the embedding of ClassSheet models in spreadsheet systems. ClassSheet models are well-known and describe the business logic of spreadsheet data. We embed this domain specific model representation on the (general purpose) spreadsheet system it models. By defining such an embedding, we provide end users a model-driven engineering spreadsheet developing environment. End users can interact with both the model and the spreadsheet data in the same environment. Moreover, we use advanced techniques to evolve spreadsheets and models and to have them synchronized. In this paper we present our work on extending a widely used spreadsheet system with such a model-driven spreadsheet engineering environment.

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


From Spreadsheets to Relational Databases and Back, Cunha, Jácome, Saraiva João, and Visser Joost , Proceedings of the 2009 ACM SIGPLAN Workshop on Partial Evaluation and Program Manipulation, New York, NY, USA, p.179–188, (2009) Abstractpepm09.pdf

This paper presents techniques and tools to transform spreadsheets into relational databases and back. A set of data refinement rules is introduced to map a tabular datatype into a relational database schema. Having expressed the transformation of the two data models as data refinements, we obtain for free the functions that migrate the data. We use well-known relational database techniques to optimize and query the data. Because data refinements define bidirectional transformations we can map such database back to an optimized spreadsheet. We have implemented the data refinement rules and we have constructed tools to manipulate, optimize and refactor Excel-like spreadsheets.

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.

From Relational ClassSheets to UML+OCL, Cunha, Jácome, Fernandes João Paulo, and Saraiva João , Proceedings of the Software Engineering Track at the 27th Annual ACM Symposium On Applied Computing (SAC 2012), p.1151–1158, (2012) Abstractsac-se12.pdf

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.

Embedding Model-Driven Spreadsheet Queries in Spreadsheet Systems, Cunha, Jácome, Fernandes João Paulo, Mendes Jorge, Pereira Rui, and Saraiva João , Proceedings of the 2014 IEEE Symposium on Visual Languages and Human-Centric Computing, Washington, DC, USA, p.151-154, (2014) Abstractvlhcc14.pdf

Spreadsheets are widely used not only to define mathematical expressions, but also to store large and complex data. To query such data is usually a difficult task to perform, usually for end user. In this work we embed the textual query language in the model-driven spreadsheet environment as a spreadsheet itself. The result is an expressive and powerful query environment that has knowledge of the business logic defined by the spreadsheet data (the spreadsheet model) to guide end users constructing correct queries.

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.