A waypoint-based mission planner for a farmland coverage with an aerial robot - a precision farming tool

Remote sensing (RS) with aerial robots is becoming more usual in every day time in Precision Agriculture (PA) practices, do to their advantages over conventional methods. Usually, available commercial platforms providing off-the-shelf waypoint navigation are adopted to perform visual surveys over crop fields, with the purpose to acquire specific image samples. The way in which a waypoint list is computed and dispatched to the aerial robot when mapping non empty agricultural workspaces has not been yet discussed. In this paper we propose an offline mission planner approach that computes an efficient coverage path subject to some constraints by decomposing the environment approximately into cells. Therefore, the aim of this work is contributing with a feasible waypoints-based tool to support PA practice

Virtual sensor networks: collaboration and resource sharing

This thesis contributes to the advancement of the Sensing as a Service (SeaaS), based on cloud infrastructures, through the development of models and algorithms that make an efficient use of both sensor and cloud resources while reducing the delay associated with the data flow between cloud and client sides, which results into a better quality of experience for users. The first models and algorithms developed are suitable for the case of mashups being managed at the client side, and then models and algorithms considering mashups managed at the cloud were developed. This requires solving multiple problems: i) clustering of compatible mashup elements; ii) allocation of devices to clusters, meaning that a device will serve multiple applications/mashups; iii) reduction of the amount of data flow between workplaces, and associated delay, which depends on clustering, device allocation and placement of workplaces. The developed strategies can be adopted by cloud service providers wishing to improve the performance of their clouds. Several steps towards an efficient Se-aaS business model were performed. A mathematical model was development to assess the impact (of resource allocations) on scalability, QoE and elasticity. Regarding the clustering of mashup elements, a first mathematical model was developed for the selection of the best pre-calculated clusters of mashup elements (virtual Things), and then a second model is proposed for the best virtual Things to be built (non pre-calculated clusters). Its evaluation is done through heuristic algorithms having such model as a basis. Such models and algorithms were first developed for the case of mashups managed at the client side, and after they were extended for the case of mashups being managed at the cloud. For the improvement of these last results, a mathematical programming optimization model was developed that allows optimal clustering and resource allocation solutions to be obtained. Although this is a computationally difficult approach, the added value of this process is that the problem is rigorously outlined, and such knowledge is used as a guide in the development of better a heuristic algorithm.Esta tese contribui para o avanço tecnológico do modelo de Sensing as a Service (Se-aaS), baseado em infraestrutura cloud, através do desenvolvimento de modelos e algoritmos que resolvem o problema da alocação eficiente de recursos, melhorando os métodos e técnicas atuais e reduzindo os tempos associados `a transferência dos dados entre a cloud e os clientes, com o objetivo de melhorar a qualidade da experiência dos seus utilizadores. Os primeiros modelos e algoritmos desenvolvidos são adequados para o caso em que as mashups são geridas pela aplicação cliente, e posteriormente foram desenvolvidos modelos e algoritmos para o caso em que as mashups são geridas pela cloud. Isto implica ter de resolver múltiplos problemas: i) Construção de clusters de elementos de mashup compatíveis; ii) Atribuição de dispositivos físicos aos clusters, acabando um dispositivo físico por servir m´ múltiplas aplicações/mashups; iii) Redução da quantidade de transferência de dados entre os diversos locais da cloud, e consequentes atrasos, o que dependente dos clusters construídos, dos dispositivos atribuídos aos clusters e dos locais da cloud escolhidos para realizar o processamento necessário. As diferentes estratégias podem ser adotadas por fornecedores de serviço cloud que queiram melhorar o desempenho dos seus serviços.(…

Effects of pharmaceuticals on the reproduction of aquatic organisms: a meta-analysis

Trabalho de projecto de mestrado, Bioestatística, Universidade de Lisboa, Faculdade de Ciências, 2019Pharmaceutical compounds have been discharged into the environment for as long as they have been produced. Many of these pharmaceuticals can disperse directly into the environment or through sewage plants, contaminating rivers, estuaries and interacting with non-target organisms. Though their concentrations in the aquatic environment are often low, these drugs are designed to produce biological effects at low concentrations, targeting specific metabolic pathways. Though research on the impacts of pharmaceuticals in aquatic organisms is growing substantially, we still lack clear understanding on the topic. This study aims to provide quantitative insight on the effects of antidepressants in the reproduction of fish and crustaceans. To address this, multilevel meta-analysis was performed. It consisted of 19 studies from research literature investigating effects of antidepressant exposure in fish or crustaceans’ reproduction according to specific selection criteria. Following standard procedures used in meta-analytic studies, heterogeneity analysis was performed and the moderating effect of concentration, exposure time, organism group and toxicant was tested. Additionally, publication bias was also addressed. The results showed that, overall, there is no significant association between antidepressant exposure and the reproduction of fish and crustaceans. Moderator analysis revealed, however, that concentration is a significant moderator for fish and crustatea fecundity. Fish and crustatea showed contrary results when accounting for this moderator. The former had a small, yet positive effect (g=0:368), meaning that increased concentrations result in increased fish fecundity, and the latter a negative, in magnitude slightly larger, effect (g = 0:453), meaning a decrease in crustaceans’ fecundity with a concentration rise. These findings help us understand that though antidepressants can have effects on reproductive outcomes in aquatic organisms, as narrative reviews address, other factors can have an important role. In spite of this, more research on the subject is need since meta-analysis are only as statistically powerful as the number of studies they include

Picturebooks as Vehicles: Creating Materials for Pedagogical Action

publishedVersio

Creating materials for pedagogical action

UIDB/04097/2020 UIDP/04097/2020Picturebooks have long been positioned as vehicles to support teachers and their learners to explore compelling and challenging themes in early English language education and more recently to support the development of intercultural and citizenship education. This article reports on the materials development phase of a professional development course which formed part of an Erasmus+ project. Its main goal was to enable teacher-participants to confidently plan for, manage and assess intercultural citizenship education through picturebooks in early ELT and to successfully co-create a set of pedagogical materials. Based on a reflective practice approach, we highlight how the professional development course incorporated the applied science, craft and reflective model over two course iterations to support a collaborative picturebook-based materials writing process. An evaluation of the draft materials was undertaken to assess the strengths and weaknesses of teaching and learning sequences for intercultural awareness and citizenship, and to inform and shape two subsequent course iterations. We conclude this paper with reflections on how we addressed certain challenges that we encountered to support teacher-participants to craft materials around picturebooks for intercultural citizenship education.publishersversionpublishe

Análise experimental e numérica da conexão aço-betão leve realizada com pernos de cabeça

O presente trabalho procura abordar a modelação numérica da conexão entre o perfil metálico e a laje de betão, quando se utilizam conectores do tipo perno e betão leve. Utilizam se elementos finitos de volume para definir todos os elementos presentes na ligação, recorrendo ao software ATENA 3D. A partir dos modelos desenvolvidos procura-se avaliar quais os parâmetros relevantes para o comportamento da conexão aço betão leve. Recorre-se a resultados de ensaios de tipo push out anteriormente realizados na Universidade do Minho para validar os modelos numéricos desenvolvidos

Radiation balance of an isolated holm oak tree (Quercus rotundifolia Lam.) in a mediterranean savannah-type woodland

In closed canopy forests the energy absorbed by the trees can be adequately estimated solely from the vertical radiation fluxes. However, in isolated or widely spaced trees this approach is no longer valid and radiation fluxes in all directions must be accounted for. An adequate estimate of the tree available energy is critical to model and calculate both interception losses and transpiration. Within a study where interception loss in a sparse evergreen oak woodland (montado) of Southern Portugal is evaluated and mod¬elled, the net amount of radiant energy absorbed by an isolated holm oak tree (Q) was measured under different radiation conditions. The measuring and calculating proce¬dure was based on the integration of the flux density of net radiation (Rn) at different points of a cylindrical surface (S) enclosing the tree crown. A set of 4 net radiome¬ters were used: one at a fixed position, on the top of the crown, and the remaining 3 mounted on a standing structure that could be moved around the tree to measure Rn fluxes through the inferior and lateral sides. Measurements of Q were made for 8 dif¬ferent days, during the first 3 months of 2006. Night time measurements of Rn were also done, but with the net radiometers at fixed positions around the tree. The meteoro¬logical conditions during the measurements included clear sky and cloudy days, some of which with light rain. Net radiation at the top of the crown accounted for about 72 % of the total energy absorbed by the tree, and this is reflected by the good linear fit between Q and Rn above the crown. Meteorological conditions seem to have some influence on this relationship, as suggested by the differences on the adjusted linear models when total, clear sky, cloudy or rainy data sets were used. The occurrence of rain tends to cause a slight increase in Q in comparison to dry conditions, for identical levels of Rn. Q also shows a strong linear response to solar radiation (Rs), given the dependence of net radiation upon short wave radiation. The same happens with the component of Q received by the top crown surface. However, energy absorbed lat¬erally is much less dependent on Rs, and the inferior component of Q is completely independent of solar radiation. Under conditions when rainfall interception is most likely to occur, i.e. cloudy/rainy days, the daily time-course of Q follows closely those of Rs and Rn, with a maximum of only 75 W m-2 (expressed per unit of leaf area). Similar maximum daily values were observed in other studies with different species but under similar weather conditions. During the night, net radiation should not have a significant spatial variability and Rn around the canopy should be relatively homo¬geneous. Accordingly, night time estimates of Q were obtained from measurements of Rn at fixed positions, which were considered representative of the Rn fluxes around the tree

O repositório de conteúdo digital nas pesquisas de história da educação matemática

Disponível em: http://ojs.fe.unicamp.br/index.php/RIDPHE-R/article/view/7307/6232Este texto apresenta o Repositório de Conteúdo Digital utilizado pelo GHEMAT – Grupo de Pesquisa de História da Educação Matemática. Este espaço virtual, sediado fisicamente na Universidade Federal de Santa Catarina, abriga as digitalizações dos documentos mobilizados nos projetos em andamento deste grupo de pesquisa. O seu uso tem se demonstrado profícuo pois permite o compartilhamento destas fontes em diversas localidades, potencializando as pesquisas em caráter histórico comparativas realizadas por projetos temáticos envolvendo grande número de pesquisadores nos diversos estados brasileiros. Por fim, são apresentados alguns exemplos de produções acadêmicas do grupo de pesquisa apoiados no uso do Repositório, tanto do ponto de vista de sua elaboração/produção assim como posterior divulgação/publicação

Aerodynamic conductances in a sparse mixed oak woodland (Quercus rotundifolia Lam. and Quercus suber L.)

The study of heat and mass exchange between the vegetation and its local environment plays a central role in the analysis of plant-atmosphere interactions. These studies can be undertaken at different scales, ranging from individual leaves to isolated trees or even the canopy scale. In each of these cases, heat and mass fluxes depend on the use of adequate values of transfer conductances. Within a broader study on interception loss from a sparse cork and holm oak woodland (montado) of Southern Portugal, aerodynamic conductances were determined for the boundary layers of both leaves (LBL) and the entire canopy