Browsing by Author "Oliveira, Nuno"
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- Adaptative Perturbation Patterns: Realistic Adversarial Learning for Robust Intrusion DetectionPublication . Vitorino, João; Oliveira, Nuno; Praça, IsabelAdversarial attacks pose a major threat to machine learning and to the systems that rely on it. In the cybersecurity domain, adversarial cyber-attack examples capable of evading detection are especially concerning. Nonetheless, an example generated for a domain with tabular data must be realistic within that domain. This work establishes the fundamental constraint levels required to achieve realism and introduces the Adaptative Perturbation Pattern Method (A2PM) to fulfill these constraints in a gray-box setting. A2PM relies on pattern sequences that are independently adapted to the characteristics of each class to create valid and coherent data perturbations. The proposed method was evaluated in a cybersecurity case study with two scenarios: Enterprise and Internet of Things (IoT) networks. Multilayer Perceptron (MLP) and Random Forest (RF) classifiers were created with regular and adversarial training, using the CIC-IDS2017 and IoT-23 datasets. In each scenario, targeted and untargeted attacks were performed against the classifiers, and the generated examples were compared with the original network traffic flows to assess their realism. The obtained results demonstrate that A2PM provides a scalable generation of realistic adversarial examples, which can be advantageous for both adversarial training and attacks.
- Anticipatory postural adjustments during sitting reach movement in post-stroke subjectsPublication . Pereira, Soraia; Silva, Cláudia; Ferreira, Sílvia; Silva, Cláudia; Oliveira, Nuno; Santos, Rubim; Vilas Boas, João; Correia, Miguel V.The study assessed the effect of velocity of arm movement on the generation of APAs in the contralateral and ipsilateral muscles of individuals with stroke in the sitting position. In the sitting position, 10 healthy and 8 post-stroke subjects reached for an object placed at the scapular plane and mid-sternum height at self-selected and fast velocities. Electromyography was recorded from the anterior deltoid (AD), upper (UT) and lower trapezius (LT), and latissimus dorsi (LD). Kinematic analysis was used to assess peak velocity and trunk displacement. Post-stroke subjects presented a delay of APAs on both sides of the body compared to healthy subjects. Differences were found between the timing of APAs on the ipsilateral and contralateral LD and LT in both movement speeds and in the ipsilateral UT during movement of the non-affected arm at a self-selected velocity. A delay in the contralateral LD in the reaching movement with the non-affected arm at fast velocity was also observed. Trunk displacement was greater in post-stroke subjects. In the sitting position, APAs were delayed in both fast and self-selected movements on both sides in post-stroke subjects, which also presented a higher trunk displacement.
- Anticipatory postural adjustments in the shoulder girdle in the reach movement performed in standing by post-stroke subjectsPublication . Silva, Cláudia F.; Pereira, Soraia; Silva, Cláudia; Ferreira, Sílvia; Oliveira, Nuno; Santos, RubimAfter a stroke in middle cerebral artery territory, there is a high probability of dysfunction of the ventromedial pathways, mainly related with postural control mechanisms such as the anticipatory postural adjustments (APAs). According to neuroanatomical knowledge, these pathways have a predominant ipsilesional disposition, which justifies a bilateral postural control dysfunction, often neglected in rehabilitation. In order to assess this bilateral postural control dysfunction, electromyography activity was assessed in eight post-stroke and 10 healthy individuals in the anterior deltoids, the superior and lower trapezius, and the latissimus dorsi as they reached for a bottle with both upper limbs separately at a self-selected velocity and fast velocity while standing associated with trunk kinematics analysis. Through this analysis it was possible to compare the timing of APAs in scapular muscles between sides in post-stroke and with healthy individuals, and to verify if there is a relation between the timing and the displacement of the trunk in the temporal window of the APAs. Indeed, post-stroke individuals show a delayed activation of APAs on scapular girdle muscles on both ipsilesional and contralesional sides, which were not reflected in the trunk displacement.
- Formação pedagógica no ensino superior: desafios e oportunidadesPublication . Salgado, Ana; Freitas, Ana; Oliveira, Nuno; Sá, SofiaHistoricamente, no contexto do ensino superior, os critérios de recrutamento e seleção de professores para integração no corpo docente baseiam-se quase exclusivamente no grau académico e mérito/produção científica do candidato. Durante décadas, prolongou-se a tradição de que um docente com competências científicas era, naturalmente, competente a nível pedagógico, vigorando assim o modelo do ‘aprende-se a ensinar, ensinando’, de forma intuitiva, por ‘tentativa-erro’. Contrariando a perspetiva acima descrita, reconhecendo a atividade docente como tarefa complexa e exigente, que carece de mais do que apenas capacidades inatas e para a qual é necessário um conjunto de saberes que potencie a efetiva aprendizagem dos estudantes e promova a qualidade do ensino, diversas instituições do ensino superior (IES) têm apostado na formação pedagógica dos seus docentes, um pouco por todo o país, contando para tal com formadores pedagógicos. Estes formadores são, geralmente, da área psicoeducativa, integrados ou não nas instituições, que trabalham, com os docentes, estratégias reconhecidas pela investigação como eficazes, ao mesmo tempo que promovem reflexões sobre o processo de ensino-aprendizagem, avaliação e outros aspetos relevantes. Esta proposta visa apresentar boas práticas internacionalmente reconhecidas na promoção de formação pedagógica para docentes, discutindo à luz das mesmas o que tem sido implementado em várias IES nacionais. É ainda intenção dos autores refletir sobre o potencial da promoção e implementação de formação pedagógica para docentes no sentido de partilhar estratégias que conduzam a um modelo eficaz de desenvolvimento da carreira docente. Esta proposta apresenta assim, nas várias fases do planeamento da formação pedagógica para docentes, questões que concernem: o formato da formação (e.g. workshops de curta duração, ações de formação de duração média e longa e formação on-the-job); a duração da mesma (workshops de 90 a 180 minutos, uma manhã/uma tarde, vários dias, um semestre...); a metodologia utilizada pelos formadores (utilização de metodologias ativas que promovam a integração dos conteúdos e a reflexão) assim como os próprios temas da formação (orientações top-down ou baseadas em análises de necessidades - bottom up). Um aspeto importante a abordar será ainda o modelo da formação - o modelo teasers pedagógicos, em que os docentes adquirem conhecimento de novas ferramentas pedagógicas para utilizar em sala de aula (e.g.: mindmaps, quizzes, apresentações dinâmicas) ou uma perspetiva conceptual com o objetivo de promover reflexão sobre temas fulcrais como planificação de aulas, aspetos ensino aprendizagem e/ou avaliação. Por outro lado, em formação on-the-job surge ainda o modelo de observações de aulas com feedback posterior, permitindo ao docente receber, de forma profissional e detalhada, informações sobre a sua prática em sala de aula com vista a posteriores melhorias e mudanças, num ambiente colaborativo e isento de processos avaliativos. A este propósito discute-se ainda a questão do público-alvo. Ainda neste âmbito convirá refletir se os modelos e temas da formação deverão ser os mesmos para docentes recém integrados e docentes experientes, discutindo-se a necessidade de diferentes formas de planeamento consoante a população-alvo. Serão ainda abordados desafios e constrangimentos relacionados com a parte burocrática e logística do planeamento da formação pedagógica como a questão do financiamento necessário para o desenvolvimento destas iniciativas e o número de participantes por ação, entre outro. Este trabalho apresenta-se como uma reflexão, fruto do trabalho desenvolvido por 4 profissionais da formação pedagógica, ligados pelos mais de 10 anos de experiência. A paixão pela área pedagógica nasce do desejo de contribuir para melhores processos de ensino aprendizagem e é alimentada pela abertura, disponibilidade e vontade dos docentes em adquirir conhecimentos que lhes permitam assumir a atividade docente com mais confiança e com novas estratégias fundamentadas na investigação.
- Machine Reading at Scale: A Search Engine for Scientific and Academic ResearchPublication . Sousa, Norberto; Oliveira, Nuno; Praça, IsabelThe Internet, much like our universe, is ever-expanding. Information, in the most varied formats, is continuously added to the point of information overload. Consequently, the ability to navigate this ocean of data is crucial in our day-to-day lives, with familiar tools such as search engines carving a path through this unknown. In the research world, articles on a myriad of topics with distinct complexity levels are published daily, requiring specialized tools to facilitate the access and assessment of the information within. Recent endeavors in artificial intelligence, and in natural language processing in particular, can be seen as potential solutions for breaking information overload and provide enhanced search mechanisms by means of advanced algorithms. As the advent of transformer-based language models contributed to a more comprehensive analysis of both text-encoded intents and true document semantic meaning, there is simultaneously a need for additional computational resources. Information retrieval methods can act as low-complexity, yet reliable, filters to feed heavier algorithms, thus reducing computational requirements substantially. In this work, a new search engine is proposed, addressing machine reading at scale in the context of scientific and academic research. It combines state-of-the-art algorithms for information retrieval and reading comprehension tasks to extract meaningful answers from a corpus of scientific documents. The solution is then tested on two current and relevant topics, cybersecurity and energy, proving that the system is able to perform under distinct knowledge domains while achieving competent performance.
- SMS-I: Intelligent Security for Cyber–Physical SystemsPublication . Maia, Eva; Sousa, Norberto; Oliveira, Nuno; Wannous, Sinan; Sousa, Orlando; Praça, IsabelCritical infrastructures are an attractive target for attackers, mainly due to the catastrophic impact of these attacks on society. In addition, the cyber–physical nature of these infrastructures makes them more vulnerable to cyber–physical threats and makes the detection, investigation, and remediation of security attacks more difficult. Therefore, improving cyber–physical correlations, forensics investigations, and Incident response tasks is of paramount importance. This work describes the SMS-I tool that allows the improvement of these security aspects in critical infrastructures. Data from heterogeneous systems, over different time frames, are received and correlated. Both physical and logical security are unified and additional security details are analysed to find attack evidence. Different Artificial Intelligence (AI) methodologies are used to process and analyse the multi-dimensional data exploring the temporal correlation between cyber and physical Alerts and going beyond traditional techniques to detect unusual Events, and then find evidence of attacks. SMS-I’s Intelligent Dashboard supports decision makers in a deep analysis of how the breaches and the assets were explored and compromised. It assists and facilitates the security analysts using graphical dashboards and Alert classification suggestions. Therefore, they can more easily identify anomalous situations that can be related to possible Incident occurrences. Users can also explore information, with different levels of detail, including logical information and technical specifications. SMS-I also integrates with a scalable and open Security Incident Response Platform (TheHive) that enables the sharing of information about security Incidents and helps different organizations better understand threats and proactively defend their systems and networks.