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Publications

Publications by CSE

2014

Target Oriented Relational Model Finding

Authors
Cunha, A; Macedo, N; Guimarães, T;

Publication
Fundamental Approaches to Software Engineering - 17th International Conference, FASE 2014, Held as Part of the European Joint Conferences on Theory and Practice of Software, ETAPS 2014, Grenoble, France, April 5-13, 2014, Proceedings

Abstract
Model finders are becoming useful in many software engineering problems. Kodkod [19] is one of the most popular, due to its support for relational logic (a combination of first order logic with relational algebra operators and transitive closure), allowing a simpler specification of constraints, and support for partial instances, allowing the specification of a priori (exact, but potentially partial) knowledge about a problem's solution. However, in some software engineering problems, such as model repair or bidirectional model transformation, knowledge about the solution is not exact, but instead there is a known target that the solution should approximate. In this paper we extend Kodkod's partial instances to allow the specification of such targets, and show how its model finding procedure can be adapted to support them (using both PMax-SAT solvers or SAT solvers with cardinality constraints). Two case studies are also presented, including a careful performance evaluation to assess the effectiveness of the proposed extension. © 2014 Springer-Verlag.

2014

A data warehouse to support web site automation

Authors
Domingues, MA; Soares, C; Jorge, AM; Rezende, SO;

Publication
Journal of the Brazilian Computer Society

Abstract
Background: Due to the constant demand for new information and timely updates of services and content in order to satisfy the user’s needs, web site automation has emerged as a solution to automate several personalization and management activities of a web site. One goal of automation is the reduction of the editor’s effort and consequently of the costs for the owner. The other goal is that the site can more timely adapt to the behavior of the user, improving the browsing experience and helping the user in achieving his/her own goals. Methods: A database to store rich web data is an essential component for web site automation. In this paper, we propose a data warehouse that is developed to be a repository of information to support different web site automation and monitoring activities. We implemented our data warehouse and used it as a repository of information in three different case studies related to the areas of e-commerce, e-learning, and e-news. Result: The case studies showed that our data warehouse is appropriate for web site automation in different contexts. Conclusion: In all cases, the use of the data warehouse was quite simple and with a good response time, mainly because of the simplicity of its structure. © 2014, Domingues et al.; licensee Springer.

2014

3rd Symposium on Languages, Applications and Technologies, SLATE 2014, June 19-20, 2014 - Bragança, Portugal

Authors
Pereira, MJV; Leal, JP; Simões, A;

Publication
SLATE

Abstract

2014

JSON on mobile: Is there an efficient parser?

Authors
Queiros, R;

Publication
OpenAccess Series in Informatics

Abstract
The two largest causes for battery consumption on mobile devices are related with the display and network operations. Since most application need to share data and communicate with remote servers, communications should be as lightweight and efficient as possible. In network communication, serialization plays a central role as the process of converting an object into a stream of bytes. One of the most popular data-interchange format is JSON (JavaScript Object Notation). This paper presents a survey on JSON parsers in mobile scenarios. The aim of the survey is to find the most efficient JSON parser in mobile communications characterised by high transfer rate of small amounts of data. In the performance benchmark we compare the time required to read and write data with several popular JSON parser implementations such as Gson, Jackson, org.json and others. The results of this survey are important for others that need to select an efficient parser for mobile communication. © Ricardo Queirós.

2014

Bidirectional Spreadsheet Formulas

Authors
Macedo, N; Pacheco, H; Sousa, NR; Cunha, A;

Publication
2014 IEEE SYMPOSIUM ON VISUAL LANGUAGES AND HUMAN-CENTRIC COMPUTING (VL/HCC 2014)

Abstract
Bidirectional transformations have potential applications in a vast number of computer science domains. Spreadsheets, on the other hand, are widely used for developing business applications, but their formulas are unidirectional, in the sense that their result can not be edited and propagated back to their input cells. In this paper, we interpret such formulas as a well-known class of bidirectional transformations that go by the name of lenses. Being aimed at users that are not proficient with programming languages, we devote particular attention to the seamless embedding of the proposed bidirectional mechanism with the typical workflow of spreadsheet environments, allowing users to have a fine control and understanding of the behavior of the derived backward transformations.

2014

Automatic Heart Sound Segmentation and Murmur Detection in Pediatric Phonocardiograms

Authors
Pedrosa, J; Castro, A; Vinhoza, TTV;

Publication
2014 36TH ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY (EMBC)

Abstract
The digital analysis of heart sounds has revealed itself as an evolving field of study. In recent years, numerous approaches to create decision support systems were attempted. This paper proposes two novel algorithms: one for the segmentation of heart sounds into heart cycles and another for detecting heart murmurs. The segmentation algorithm, based on the autocorrelation function to find the periodic components of the PCG signal had a sensitivity and positive predictive value of 89.2% and 98.6%, respectively. The murmur detection algorithm is based on features collected from different domains and was evaluated in two ways: a random division between train and test set and a division according to patients. The first returned sensitivity and specificity of 98.42% and 97.21% respectively for a minimum error of 2.19%. The second division had a far worse performance with a minimum error of 33.65%. The operating point was chosen at sensitivity 69.67% and a specificity 46.91% for a total error of 38.90% by varying the percentage of segments classified as murmurs needed for a positive murmur classification.

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