Browsing by Issue Date, starting with "2024-06-26"
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- Evaluation of MCP Correlation Algorithms Applied to Wind Data SeriesPublication . Moreira, A.; Rocha, T.; Mendonça, J.; Pilão, R.; Pinto, P.This work aimed to develop methodologies for analysing statistical correlations among wind data series using various Measure-Correlate-Predict (MCP) methods, with the goal of selecting the most suitable method for extrapolating long-term data with minimal associated uncertainty. It was analysed the minimum time required for a wind measurement campaign when applying this methodology. Fifteen local wind measurement stations were selected. The long-term wind data reanalysis series that exhibited the strongest correlation with the measured wind data at each station was then chosen. Multiple tests were conducted with different simultaneous periods between the measured data series and the long-term series. Fifteen correlation algorithms were tested for each concurrent period. The performance of each model was evaluated using the RMSE (Root Mean Square Error) and MBE (Mean Bias Error) associated with each MCP. Analysis of the errors identified measurement periods with the lowest associated error ranging from 1 to 5 years and a single-factor ANOVA analysis was conducted. Finally, t-significance tests were performed. The study concluded that the Neural Network was the most effective MCP method. Additionally, it was determined that the minimum number of years required for a local measurement campaign should be between 2 and 3 years.
- VISIR Remote Laboratory: The Switching Matrix LimitationsPublication . Jacob, Frederico L.; Fidalgo, André V.; Ruiz, Elio San Cristobal; Loro, Felix Garcia; Lázaro Jacob, Frederico; Fidalgo, AndréIn a rapidly evolving world, technology plays a fundamental role in transforming the way students learn and interact with theoretical and practical concepts. A striking example of this progress is the Virtual Instrument Systems in Reality (VISIR), a popular remote laboratory platform developed for teaching specific subjects such as analog electronics and electricity. This laboratory allows students to conduct practical experiments over the internet, potentially using real equipment, installed in a distant location, and controlled remotely. Therefore, students can access the VISIR remote laboratory through a web browser and interact with instruments and circuits as if they were in a conventional laboratory. However, probably because it has not received any relevant updates for quite some time, this platform presents several limitations, which will be explored in this paper, essentially those currently existing in the Switching Matrix. This approach was based on information published in scientific literature combined with feedback from intensive user and owner experiences. This evaluation aims to identify various weaknesses (technical, educational or pedagogical, operational, and economical) of the Switching Matrix, which may be considered threats to the future of the VISIR remote laboratory and affect its performance and stability, as well as its expansion to a wider community of users. It should be noted that suggestions for solutions to correct the limitations of this part of the remote platform are not given.
- Comunicação dialógica nos websites dos restaurantes Michelin em PortugalPublication . Oliveira, João Miguel Sousa de; Oliveira, Adriana José Veloso deAs transformações tecnológicas no digital têm restruturado profundamente a forma como comunicamos e interagimos. Com a crescente expansão da Internet e novos media digitais, os meios de comunicação modernos tornaram-se centrais na vida quotidiana, sendo, por isso, imperativo estudar o papel dos meios de comunicação modernos, em particular os websites. Como tal, ainda que esta evolução tenha impactado positivamente o acesso à informação e a comunicação ativa, emergem novos desafios nos mais diversos setores. O setor do turismo, especialmente os restaurantes, tem sido significativamente impactado por estas transformações. Este estudo, por sua vez, foca-se na teoria da Comunicação Dialógica, com pesquisa a ter como objetivo principal estudar a adoção da comunicação dialógica, através do princípio Ciclo Dialógico, pelo setor de Restauração Michelin em Portugal, e objetivos específicos os seguintes: reconhecer o website do Restaurante Michelin com maior e menor grau de adoção do ciclo dialógico; identificar o grau de adoção dos indicadores do Ciclo Dialógico nos websites dos Restaurantes Michelin; identificar os indicadores mais e menos aplicados pelos websites dos Restaurantes Michelin; identificar quais os indicadores do Ciclo Dialógico mais adotados pelo público no contexto de websites de Restaurantes Michelin; identificar as razões que levam os utilizadores a visitarem websites de restaurantes Michelin; realizar uma análise cruzada dos resultados obtidos pela grelha de análise aos websites e os resultados do questionário relativamente à presença dos indicadores do Ciclo Dialógico nos websites de restaurantes Michelin. Para alcançar este propósito, a investigação implementou uma abordagem mista, combinando dados quantitativos e qualitativos. A recolha dos dados foi feita através de uma grelha de análise e um inquérito por questionário. Após análise dos dados, podemos concluir que os websites dos restaurantes Michelin em Portugal mostram uma baixa adoção da comunicação dialógica através do princípio do Ciclo Dialógico, que as principais razões pelas quais os utilizadores que se expõem ao conteúdo dos websites estão associadas à procura de informação e interação, sendo que os dois indicadores aos quais dão maior importância são: Partilha de experiências vividas pelos utilizadores (textos) e Partilha de experiências vividas pelos utilizadores (fotografias).
- Validation of a methodology for post-construction Energy Yield Assessment of an operational wind farmPublication . Costa, M.; Rocha, T.; Mendonça, J.; Pilão, R.; Pinto, P.The uncertainty associated with the prospective Energy Yield Assessment (EYA) of a wind farm may be reduced by re estimating the energy yield after it enters normal operation. This study aims to validate a simple methodology for conducting post-construction EYA of an operational wind farm. The proposed methodology derives a linear relationship between a historical source of wind speed data and the observed wind farm production on a monthly basis. In a first stage, the impact of different data sources on the accuracy of the Long-Term energy yield estimate was assessed. Results suggest that the determination coefficient R 2 is a reliable indicator for selecting the most adequate source of historical wind speed data to be used in the Long-Term energy yield estimate. In a second stage, the model was validated from a statistical point of view by testing the premises of the linear regression model, namely the significance of the linear correlation (ANOVA test), and normally-distributed (Shapiro-Wilk test), non-self-correlated (Durbin-Watson), homoscedastic (Breusch-Pagan test) residuals. Results show these premises are verified for most test cases, indicating that the model is statistically robust that the model is statistically robust for most test cases.