1,030 research outputs found
Coletânea de resumos de trabalhos realizados no Campo Experimental de Paragominas, Pará.
São apresentados os resumos de pesquisas realizadas no CEP e publicadas no perÃodo de 1978 a 1998, juntamente com as respectivas referências bibliográficas para consultas mais detalhadas. E, após os resumos, são apresentados os Ãndices remissivos por autor e por assunto.bitstream/item/63187/1/Oriental-Doc35.pd
Decision-Making Under Uncertainty: Beyond Probabilities
This position paper reflects on the state-of-the-art in decision-making under
uncertainty. A classical assumption is that probabilities can sufficiently
capture all uncertainty in a system. In this paper, the focus is on the
uncertainty that goes beyond this classical interpretation, particularly by
employing a clear distinction between aleatoric and epistemic uncertainty. The
paper features an overview of Markov decision processes (MDPs) and extensions
to account for partial observability and adversarial behavior. These models
sufficiently capture aleatoric uncertainty but fail to account for epistemic
uncertainty robustly. Consequently, we present a thorough overview of so-called
uncertainty models that exhibit uncertainty in a more robust interpretation. We
show several solution techniques for both discrete and continuous models,
ranging from formal verification, over control-based abstractions, to
reinforcement learning. As an integral part of this paper, we list and discuss
several key challenges that arise when dealing with rich types of uncertainty
in a model-based fashion
Creating a benchmark of vertical axis wind turbines in dynamic stall for validating numerical models
Experiências de Cyberbullying relatadas por estudantes do ensino superior politécnico
As TIC trouxeram múltiplos benefÃcios mas acarretam também riscos, nomeadamente o cyberbullying, ou seja, a prática de atos agressivos, intencionais e repetidos com recurso a dispositivos eletrónicos para, por exemplo, enviar mensagens insultuosas ou criar websites que difamam e hostilizam os outros. Este estudo teve
por objetivos conhecer a frequência e os tipos de cyberbullying praticados, sofridos e observados por estudantes do ensino superior politécnico; saber se se veriicam diferenças entre géneros e cursos; identiicar as emoções associadas aos diferentes papéis no cyberbullying; identiicar os motivos invocados pelos agressores para explicar este tipo de comportamento. Para o efeito construiu-se um questionário quantitativo que foi aplicado a 170 estudantes que frequentavam várias licenciaturas de uma instituição de ensino superior politécnico de Portugal. Os resultados revelaram que 30,6% dos estudantes já tinham sido vÃtimas de cyberbullying e 8,2% admitiu ter praticado cyberbullying, pelo menos algumas vezes. Um dos motivos mais evocados pelos agressores para esta prática foi a vingança relativamente a episódios ocorridos anteriormente. Não se veriicaram diferenças signiicativas entre sexos mas o fenómeno era mais frequente em cursos de engenharia comparativamente aos de educação e ciências humanas. Equaciona-se a prevenção do cyberbullying a partir da utilização dos próprios meios de comunicação social para promoção da
partilha de informação sobre como utilizar as TIC de forma ética e segura, bem como através da criação de programas e plataformas envolvendo estudantes de vários nÃveis de ensino com vista à prevenção deste fenómeno
Distinguishing sequences for partially specified FSMs
Distinguishing Sequences (DSs) are used inmany Finite State Machine (FSM) based test techniques. Although Partially Specified FSMs (PSFSMs) generalise FSMs, the computational complexity of constructing Adaptive and Preset DSs (ADSs/PDSs) for PSFSMs has not been addressed. This paper shows that it is possible to check the existence of an ADS in polynomial time but the corresponding problem for PDSs is PSPACE-complete. We also report on the results of experiments with benchmarks and over 8 * 106 PSFSMs. © 2014 Springer International Publishing
Factored Online Planning in Many-Agent POMDPs
In centralized multi-agent systems, often modeled as multi-agent partially
observable Markov decision processes (MPOMDPs), the action and observation
spaces grow exponentially with the number of agents, making the value and
belief estimation of single-agent online planning ineffective. Prior work
partially tackles value estimation by exploiting the inherent structure of
multi-agent settings via so-called coordination graphs. Additionally, belief
estimation methods have been improved by incorporating the likelihood of
observations into the approximation. However, the challenges of value
estimation and belief estimation have only been tackled individually, which
prevents existing methods from scaling to settings with many agents. Therefore,
we address these challenges simultaneously. First, we introduce weighted
particle filtering to a sample-based online planner for MPOMDPs. Second, we
present a scalable approximation of the belief. Third, we bring an approach
that exploits the typical locality of agent interactions to novel online
planning algorithms for MPOMDPs operating on a so-called sparse particle filter
tree. Our experimental evaluation against several state-of-the-art baselines
shows that our methods (1) are competitive in settings with only a few agents
and (2) improve over the baselines in the presence of many agents.Comment: Extended version (includes the Appendix) of the paper accepted at
AAAI-2
What Has Changed During the COVID-19 Pandemic? - The Effect on an Academic Breast Department in Portugal
Introduction: One year ago, Portugal entered its first lockdown because of the coronavirus disease-2019 (COVID-19) pandemic. The impact of this on delays in cancer diagnosis and treatment is a major concern, which may negatively affect the outcomes of these patients.
Materials and methods: This retrospective, single-center analysis compared the clinical and pathological characteristics of breast cancer (BC) patients referred to a medical oncology first appointment between March 2020 and 2021, with the same period in the previous year.
Results: Strikingly, there was a 40% reduction in the number of BC patients during lockdown. However, there was a statistically significant increase in the proportion of metastatic BC patients admitted for the first time for systemic therapy (13.6% vs. 28.9%, p = 0.003). Additionally, a statistically significant increase in the number of patients with bilateral early BC at diagnosis after March 2020 was found (7.2% vs. 1.9%, p = 0.043).
Conclusion: These findings support international recommendations for an accelerated restoration of BC screening, to reduce incidence of advanced breast cancer at diagnosis and mitigate the expected impact of the COVID-19 pandemic on patients with cancer. Further work is needed to examine in detail the impact of measures to manage the COVID-19 pandemic on breast cancer outcomes.info:eu-repo/semantics/publishedVersio
- …