Browsing by Issue Date, starting with "2024-07-29"
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- Integrating flakiness detection and repairPublication . Mendes, Alexandre Filipe de Freitas; Azevedo, Isabel de Fátima SilvaTesting is a core component of software development, safeguarding the reliability of the code. However, some tests may provide unexpected outcomes, non-deterministically passing or failing. Such tests are deemed flaky. Known to delay releases and reduce the overall effectiveness and efficiency of testing these tests have become a key problem. Affecting the entire industry, awareness, and research on the topic have risen significantly in recent years. This dissertation presents a systematic literature review on flaky test research's state of the art. It details the research methodology used and provides an overview of recent developments in the field. The review addresses four dimensions: causes, detection, repair, and tool integration. Each dimension is analyzed to classify flakiness and detail tools and methodologies capable of addressing different aspects of flakiness. In this manner, the dissertation comprehensively examines recent strategies for addressing flaky tests. Among the categories of flakiness, order-dependency has received the most research focus, with several tools available for detecting and repairing this category specifically. However, there is a notable lack of tools capable of both detecting and repairing flaky tests in a unified manner. By studying and evaluating individual tools, this dissertation assesses the potential compatibility between already existing and available methodologies, allowing for the development of a prototype for a unified order-dependency flakiness solution. Evaluating this prototype against the individual execution of its components reveals that integrating existing tools enhances usability while preserving comparable levels of recall and execution time. This analysis highlights the necessity for standardizing the inputs and outputs of order-dependency detection and repair tools. Additionally, it shows that complete detection
- Using GraphQL with graph databasesPublication . Barbosa, Tiago Filipe Nascimento; Azevedo, Isabel de Fátima SilvaGraph databases and GraphQL query language have seen increasing adoption across various industries in recent years. There is a potential synergy arising from integrating GraphQL with graph databases, raising the need to evaluate and compare this collaboration in contrast to integrating GraphQL with relational databases, especially in terms of performance and maintainability. This document explores the synergies between GraphQL and graph databases, delving into their integration, challenges, and prospects. The initial chapters establish the contextual landscape, addressing the problem, objectives, research methodology, ethical considerations, and structural organization of the study. Next, there’s an introduction to the concepts of GraphQL and graph databases, dissecting their fundamental structures, querying mechanisms, data organization, and ideal usage scenarios. This foundational understanding sets the stage for a detailed investigation into their integration, as outlined in the state-of-the-art chapter. Within this chapter, a systematic literature review is conducted where the research questions guiding the exploration of integration strategies and considerations are elucidated. The discussion encompasses primary use cases driving the adoption of GraphQL in conjunction with graph databases, the selection of suitable technologies for seamless integration, and the elucidation of key challenges impeding their widespread adoption and successful implementation. In the analysis and design phase, a project for migration is selected, using the Analytic Hierarchy Process (AHP), characterized, and architecturally explained. The migration process is then elaborated, including data modeling transformation and the technologies and approaches used. The implementation chapter describes the migration changes, with specific attention to domain classes and custom resolvers, authentication and authorization, and adjustments to the initial project. Next, the experimentation and evaluation of the solutions is achieved following the Goal, Questions, Metrics (GQM) approach, focusing on evaluating the performance and maintainability of each solution. The results are analyzed, concluding that the solution using a graph database is superior in terms of maintainability and, in some cases, in terms of performance too. With a higher number of concurrent users, the graph database solution presented better results overall. The relational database solution outperformed when using a small to medium number of users. If the queries and domain do not require deep nesting relationships, then the relational database seems more desirable, in terms of performance. Finally, the dissertation concludes with a summary of achievements, an outline of difficulties encountered, an assessment of threats to validity, and suggestions for future work.
- Cryptocurrencies and stocks: spillovers across developed and emerging markets and in bear and bull phasesPublication . Andrade, Bernardo Silva; Machado, Celsa Maria de Carvalho; Ribeiro, Anabela Paula Alferes FerreiraAs criptomoedas ganharam uma popularidade crescente como classe de ativos, mas também suscitaram preocupações quanto às suas potenciais implicações para a estabilidade financeira devido à extrema volatilidade dos preços. Este estudo examina as repercussões em termos de rendibilidade e volatilidade entre as três principais criptomoedas de capitalização bolsista e os índices bolsistas, no período de 1 de janeiro de 2016 a 30 de abril de 2024. Contribui para a literatura ao avaliar se a intensidade e os efeitos líquidos destas repercussões diferem em mercados em alta e em baixa, e entre economias emergentes e avançadas. Quanto à estratégia empírica, alargámos a abordagem de conetividade de Diebold e Yilmaz para incluir potenciais diferenças de spillover em períodos de mercados em alta e em baixa, estimadas utilizando o algoritmo de Lunde e Timmermann (2004). As conclusões deste estudo indicam que as criptomoedas e as ações mantêm características de classes de ativos separadas, mas há provas de uma interligação mais estreita durante os períodos de baixa. Sugerem também a inexistência de qualquer assimetria nas repercussões entre as criptomoedas e os mercados bolsistas das economias avançadas e emergentes, apesar da popularidade das criptomoedas nestes últimos.
- Digital surveys and BIM modelling processes and semi-automationPublication . Ferreira, Vinícius do Vale; Ribeiro, Diogo Rodrigo FerreiraThis study aims to enhance the use of advanced technologies to improve the accuracy and efficiency of 3D geometric surveys in civil engineering applications. The thesis proposes a workflow that includes in situ surveys, with and without topographic support, 2D and 3D modeling from point clouds, as well as a contribution to the automation of 3D modeling through a dedicated algorithm developed in VPL and Python. Digital surveys represent a significant advancement in documenting existing constructions, providing faster, safer, and more accurate measurements compared to traditional methods. The development of the script seeks to facilitate the modeling of structural elements from point clouds, optimizing time and reducing human errors, allowing for minor adjustments to the final model. This script has been detailed so that future work can continue to automate this workflow, which consequently increases productivity in the construction sector. The first stage of this study, conducted in collaboration with the Warsaw University of Technology, focused on a comparative analysis between the design dimensions and the actual dimensions of a structural connection plate of a railway bridge, using photogrammetry and laser scanning. In the photogrammetry process, photographs obtained from a drone without GNSS were used to create a point cloud, referenced and adjusted iteratively. The point cloud was segmented using the RANSAC method to facilitate 2D modeling. The second part aimed at semi-automatic 3D modeling, creating an algorithm based on visual programming and Python, using the results of a survey of an industrial warehouse with georeferenced photographs, laser scanning, and topographic support. This point cloud also had to be segmented using the RANSAC method to be used as input for the semi-automatic 3D modeling script.
- Relatório de estágio: Condições técnicas específicas de contenções periféricasPublication . Oliveira, Miguel Ângelo Gomes; Oliveira, Maria Do Rosário SantosO presente relatório foi escrito com o principal objetivo de relatar os trabalhos desenvolvidos durante o período do estágio curricular enquadrado no plano de estudos do 2º ano do Mestrado em Engenharia Civil do Instituto Superior de Engenharia do Porto para a obtenção do grau de Mestre em Engenharia Civil, na especialização de Construções. O estágio decorreu entre 03/01/2024 até 23/04/2024 na FEVIN- Engenharia para Instalações, Lda. O estudante integrou numa equipa de projetos com o propósito de desenvolver competências ao nível da modelação, cálculo, desenvolvimento de peças desenhadas e escritas, em projetos de estruturas de betão armado e contenções periféricas. Finalmente, este relatório caracteriza o trabalho de desenvolvimento das especificações técnicas de uma contenção periférica designada de Muro de Munique ancorado, sustentado pela aplicação dos conhecimentos adquiridos ao longo do percurso académico do estudante.
- AI-driven information retrieval system for candidate screeningPublication . Silva, Vasco Reid Ferreira da; Conceição, Luís Manuel SilvaEfficient screening and evaluation in the recruitment process are tasks that demand substantial time and effort from Human Resources professionals. These processes often suffer from long waiting periods, inconsistent candidate evaluation, and the potential to overlook qualified candidates. In this context, leveraging state-of-the-art natural language processing architectures, specifically large language models (LLMs), holds significant promise. LLMs can generate evaluations using advanced prompt techniques to improve the accuracy and reliability of the output. This thesis researches the feasibility of employing 7 billion parameter LLMs in candidate screening to reduce response times, decrease workload, and improve evaluation consistency. The study involves a comparative analysis of various state-of-the-art large language models to identify those most suitable for this application. Additionally, it examines different prompt engineering techniques to optimize the performance of these models. A comprehensive analysis of the results is conducted to determine the most effective combinations of LLMs and prompt engineering techniques. This includes a two-way validation process, utilizing both the state-of-the-art GPT-4 model and manual human resources validation, to ensure the robustness and reliability of the findings. The outcomes of this thesis aim to enhance the quality of candidate screening by integrating LLMs into the process. Furthermore, this work aspires to provide valuable insights into the capabilities of 7 billion parameter large language models in the field of human resources and their application in real-world scenarios.