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Publicações

2021

Influence of Load Dynamics on Converter-Dominated Isolated Power Systems

Autores
Gouveia, J; Moreira, CL; Lopes, JAP;

Publicação
APPLIED SCIENCES-BASEL

Abstract
The operation of isolated power systems with 100% converter-based generation requires the integration of battery energy storage systems (BESS) using grid-forming-type power converters. Under these operating conditions, load dynamics influences the network frequency and voltage following large voltage disturbances. In this sense, the inclusion of induction motor (IM) load models is required to be properly considered in BESS power converter sizing. Thus, this paper presents an extensive sensitivity analysis, demonstrating how load modeling affects the BESS power converter capacity when adopting conventional control strategies while aiming to assure the successful recovery of all IM loads following a network fault. Furthermore, this work highlights that generators with converter interfaces can actively contribute to mitigate the negative impacts resulting from IM loads following a network fault. Thereby, two distinct control strategies are proposed to be integrated in the power electronic interfaces of the available converter-based generators: one to be adopted in grid-following converters and another one suitable for grid-forming converters. The proposed control strategies provide an important contribution to consolidating insular grid codes, aiming to achieve operational scenarios accommodating 100% penetration of converter-based generation with a significative percentage of the IM load composition without resorting to a significative increase in BESS power converter sizing.

2021

A methodology and framework for software memoization of functions

Autores
Pinto, P; Cardoso, JMP;

Publicação
CF

Abstract
Enhancing performance is crucial when developing applications for high-performance and embedded computing. It requires sophisticated techniques and in-depth knowledge of the application domain and target architecture. Typically, developers prioritize the application's functional requirements over extra-functional requirements. Thus, a large part of the optimization effort is shifted to performance engineers, who rely on manual effort, alongside many analysis and optimization tools that need integration. This paper focuses on memoization, which caches results of pure computations and retrieves them if a function is called with repeating arguments. We propose a methodology for allowing developers and performance engineers to apply memoization straightforwardly by automating code analysis, code transformations, and memoization-specific profiling. It helps developers with no optimization expertise to quickly set up memoization and, simultaneously, it provides performance engineers with highly customizable analysis and memoization. We provide a concrete implementation supported by a DSL, a source-to-source compiler, and a memoization framework. We evaluate the methodology and framework with publicly available benchmarks. We show how one can analyze applications to select functions with performance improvement potential, which the experiments reveal might be challenging to find, and improve some applications with minimal effort.

2021

How Do I Feel When… A Card-Based Communication Game to Stimulate Empathy Among Family Members with Anorexia Nervosa

Autores
Peçaibes, V; Cardoso, P; Castro, L; Giesteira, B; Lopes, L; Junqueira, C;

Publicação
Springer Series in Design and Innovation

Abstract
Today, games play active roles in diverse stages of the treatment of various mental illnesses. Despite this favourable context, their use as tools in the treatment of anorexia nervosa is still quite unexplored. We are developing playful and gamified tools that can be used as instruments in the prevention, treatment and monitoring of this complex disease. The objective of this paper is to present the initial process of design and development of a card-based game called How do I feel when… Its purpose consists of stimulating empathy among family members of patients with anorexia nervosa. Play sessions are to be mediated by health professionals and are supposed to occur in the context of support and therapeutic groups for family members of people suffering from eating disorders or in clinical consultations. Preliminary tests and expert reviews showed that the game is effective in establishing free association of subjects in players’ reasonings, and in inciting the externalisation and sharing of players’ feelings. It also demonstrated that, because players usually read the cards in accordance to their life experience, the game is able to circumscribe and personalise the subjects to be discussed. © 2021, The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Switzerland AG.

2021

Fundamental privacy rights in a pandemic state

Autores
Carvalho, T; Faria, P; Antunes, L; Moniz, N;

Publicação
PLOS ONE

Abstract
Faced with the emergence of the Covid-19 pandemic, and to better understand and contain the disease's spread, health organisations increased the collaboration with other organisations sharing health data with data scientists and researchers. Data analysis assists such organisations in providing information that could help in decision-making processes. For this purpose, both national and regional health authorities provided health data for further processing and analysis. Shared data must comply with existing data protection and privacy regulations. Therefore, a robust de-identification procedure must be used, and a re-identification risk analysis should also be performed. De-identified data embodies state-of-the-art approaches in Data Protection by Design and Default because it requires the protection of direct and indirect identifiers (not just direct). This article highlights the importance of assessing re-identification risk before data disclosure by analysing a data set of individuals infected by Covid-19 that was made available for research purposes. We stress that it is highly important to make this data available for research purposes and that this process should be based on the state of the art methods in Data Protection by Design and by Default. Our main goal is to consider different re-identification risk analysis scenarios since the information on the intruder side is unknown. Our conclusions show that there is a risk of identity disclosure for all of the studied scenarios. For one, in particular, we proceed to an example of a re-identification attack. The outcome of such an attack reveals that it is possible to identify individuals with no much effort.

2021

Information Technologies in Social Entrepreneurship

Autores
Esteves, V; Malta, P; Mamede, H; Santos, V;

Publicação
Smart Innovation, Systems and Technologies

Abstract
Social organizations are usually subject to a high number of requests. In addition, it deals with a variety of problems to which an answer is needed. In this context, it is important to understand how these organizations can better support their process activity: Can technologies help to solve the problems of social organizations in a more efficient way, bringing greater benefits to the community? This paper presents a study on the use of information technologies in Portuguese social organizations to meet the needs of these organizations in responding to current challenges. © 2021, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.

2021

Does gamification in virtual reality improve second language learning?

Autores
Pinto, RD; Monteiro, P; Melo, M; Cabral, L; Bessa, M;

Publicação
ICGI

Abstract
Previous works have shown the great potential of Virtual Reality (VR) in the area of Education. This paper studies if users can learn a second language when using a gamified VR application through an English learning test and how learning influences user satisfaction, sense of presence, cybersickness, and quality of experience through questionnaires. For this purpose, the VirtualeaRn game was developed. 20 Portuguese participants were exposed to the application, and the learning test was used before and after using the application. Result analysis shows an increase in learning results after using the VR gamified application, indicating the technology's efficacy in learning a second language. A positive user satisfaction, sense of presence, and quality of experience were also found. Some cases of cybersickness were reported. The outcomes are promising and provide enough information to show the potential of the gamification of VR technology for the area of learning a second language.

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