2017
Autores
Cunha, J; Fernandes, JP; Lämmel, R; Saraiva, J; Zaytsev, V;
Publicação
Lecture Notes in Computer Science
Abstract
2017
Autores
Fernandes, JM; Afonso, P; Fonte, V; Alves, V; Ribeiro, AN;
Publicação
EUROPEAN JOURNAL OF ENGINEERING EDUCATION
Abstract
Universities seek to promote entrepreneurship through effective education approaches, which need to be in permanent evolution. Nevertheless, the literature in entrepreneurship education lacks empirical evidence. This article discusses relevant issues related to promoting entrepreneurship in the software field, based on the experience of a 15-European Credit Transfer and Accumulation System course. This course seeks to instil in the students the recognition of the need to reconcile technical and business visions, organisational and commercial aspects, most of which have never been addressed previously. A series of semi-structured interviews made it possible to obtain relevant insights about the teaching-learning process underlying this course and its evolution over a seven-year period. Materials related with this course have been analysed, namely guidelines produced by the teachers and deliverables produced by the students. This article discusses the dimensions that were identified as fundamental for promoting entrepreneurship skills in the field of software, namely teamwork, project engagement, and contact with the market.
2017
Autores
Fernandes, Tiago B.; Ribeiro, António Nestor; Nunes, David V.; Lourenço, Hugo R.; Santos, Luiz C.;
Publicação
Abstract
Software’s structure profoundly affects its development and maintenance costs. Poor software’s structure may lead to well-known design flaws, such as large modules or long methods. A possible ap- proach to reduce a module’s complexity is the Extract Method refactor- ing technique. This technique allows the decomposition of a large and complex method into smaller and simpler ones, while reducing the orig- inal method’s size and improving its readability and comprehension. The OutSystems platform is a low-code platform that allows the de- velopment of web and mobile applications that rely on a set of visual Domain-Specific Languages (DSLs). Even low-code languages when im- properly used can lead to software that has maintenance issues like long methods.
Thus, the purpose of this paper is to present the research and devel- opment done to provide the OutSystems platform with a tool that au- tomatically suggests Extract Method refactoring opportunities. The re- search combines program slicing techniques with code complexity metrics to calculate the best refactoring opportunities that preserve programs’ functionality.
The proposed approach was tested on typical OutSystems apps and was shown to be able to reduce the overall applications’ complexity.
2017
Autores
Alonso, A; Couto, R; Pacheco, H; Bessa, R; Gouveia, C; Seca, L; Moreira, J; Nunes, P; Matos, PG; Oliveira, A;
Publicação
CIRED - Open Access Proceedings Journal
Abstract
In the framework of the Horizon 2020 project UPGRID, the Portuguese demo is focused on promoting the exchange of smart metering data between the DSO and different stakeholders, guaranteeing neutrality, efficiency and transparency. The platform described in this study, named the Market Hub Platform, has two main objectives: (i) to guarantee neutral data access to all market agents and (ii) to operate as a market hub for the home energy management systems flexibility, in terms of consumption shift under dynamic retailing tariffs and contracted power limitation requests in response to technical problems. The validation results are presented and discussed in terms of scalability, availability and reliability.
2017
Autores
Zan, T; Pacheco, H; Ko, HS; Hu, Z;
Publicação
Inf. Media Technol.
Abstract
Different XML formats are widely used for data exchange and processing, being often necessary to mutually convert between them. Standard XML transformation languages, like XSLT or XQuery, are unsatisfactory for this purpose since they require writing a separate transformation for each direction. Existing bidirec- tional transformation languages mean to cover this gap, by allowing programmers to write a single program that denotes both transformations. However, they often 1) induce a more cumbersome programming style than their traditionally unidirectional relatives, to establish the link between source and target formats, and 2) offer limited configurability, by making implicit assumptions about how modifications to both formats should be translated that may not be easy to predict. This paper proposes a bidirectional XML update language called BiFluX (BIdirectional FunctionaL Updates for XML), inspired by the Flux XML update language. Our language adopts a novel bidirectional programming by update paradigm, where a program succinctly and precisely describes how to update a source document with a target document in an intuitive way, such that there is a unique "inverse" source query for each update program. BiFluX extends Flux with bidirectional actions that describe the con- nection between source and target formats. We introduce a core BiFluX language, and translate it into a formally verified bidirectional update language BiGUL to guarantee a BiFluX program is well-behaved.
2017
Autores
Alonso, Ana Luísa Parreira Nunes;
Publicação
Abstract
A common pattern for enterprise applications, particularly in small and medium
businesses, is the reliance on an integrated traditional relational database system
that provides persistence and where the relational aspect underlies the core logic
of the application. While several solutions are proposed for scaling out such
applications, database replication is key if the relational aspect is to be preserved.
However, it is worrisome that because proposed solutions for database replication
have been evaluated using simple synthetic benchmarks, their applicability
to enterprise applications is not straightforward: the performance of conservative
solutions hinges on the ability to conveniently partition applications while optimistic
solutions may experience unacceptable abort rates, compromising fairness,
particularly considering long-running transactions.
In this thesis, we address these challenges. First, by performing a detailed
evaluation of the applicability of database replication protocols based on conservative
concurrency control to enterprise applications. Results invalidate the
common assumption that real-world databases can be easily partitioned. Then,
we tackle the issue of unacceptable abort rates in optimistic solutions by proposing
a novel transaction scheduler, AJITTS, which uses an adaptive mechanism
that by reaching and maintaining the optimal level of concurrency in the system,
minimizes aborts and improves throughput.;Um padrão comum no que toca a aplicações empresariais, particularmente em pequenas e médias empresas, é a dependência de um sistema de base dados relacional integrado que garante a persistência dos dados e no qual o aspeto relacional é parte integral da logica da aplicação. Embora várias soluções tenham sido propostas para dotar este tipo de aplicações de escalabilidade horizontal, a replicação de base de dados é a solução se o aspeto relacional deve ser preservado.
No entanto, é preocupante que, dado que as soluções existentes para replicação de base de dados têm sido avaliadas utilizando testes de desempenho sintéticos e simples, a aplicabilidade destes a aplicações empresariais não é directa: o desempenho de soluções conservadoras está intimamente ligado à capacidade de particionar a aplicação convenientemente, enquanto que soluções optimistas podem sofrer de taxas de insucesso inaceitáveis o que compromete a equidade das mesmas, em particular no caso de transações especialmente longas.
Nesta tese, abordamos estes desafios. Primeiro, através de uma avaliação detalhada da aplicabilidade de protocolos de replicação de base de dados baseados em controlo de concorrência conservador a aplicações empresariais. Os resultados obtidos invalidam o pressuposto comum de que bases de dados reais podem ser facilmente particionadas. Assim sendo, abordámos o problema das possíveis taxas de insucesso inaceitáveis em soluções optimistas propondo um novo escalonador de transações, o AJITTS, que utiliza um mecanismo adaptativo que ao atingir e manter o nível ótimo de concorrência no sistema, minimiza a taxa de insucesso e melhora o desempenho do mesmo.
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