Unsupervised Graph-based Rank Aggregation for Improved Retrieval

This paper presents a robust and comprehensive graph-based rank aggregation approach, used to combine results of isolated ranker models in retrieval tasks. The method follows an unsupervised scheme, which is independent of how the isolated ranks are formulated. Our approach is able to combine arbitrary models, defined in terms of different ranking criteria, such as those based on textual, image or hybrid content representations. We reformulate the ad-hoc retrieval problem as a document retrieval based on fusion graphs, which we propose as a new unified representation model capable of merging multiple ranks and expressing inter-relationships of retrieval results automatically. By doing so, we claim that the retrieval system can benefit from learning the manifold structure of datasets, thus leading to more effective results. Another contribution is that our graph-based aggregation formulation, unlike existing approaches, allows for encapsulating contextual information encoded from multiple ranks, which can be directly used for ranking, without further computations and post-processing steps over the graphs. Based on the graphs, a novel similarity retrieval score is formulated using an efficient computation of minimum common subgraphs. Finally, another benefit over existing approaches is the absence of hyperparameters. A comprehensive experimental evaluation was conducted considering diverse well-known public datasets, composed of textual, image, and multimodal documents. Performed experiments demonstrate that our method reaches top performance, yielding better effectiveness scores than state-of-the-art baseline methods and promoting large gains over the rankers being fused, thus demonstrating the successful capability of the proposal in representing queries based on a unified graph-based model of rank fusions

Multimodal Prediction based on Graph Representations

This paper proposes a learning model, based on rank-fusion graphs, for general applicability in multimodal prediction tasks, such as multimodal regression and image classification. Rank-fusion graphs encode information from multiple descriptors and retrieval models, thus being able to capture underlying relationships between modalities, samples, and the collection itself. The solution is based on the encoding of multiple ranks for a query (or test sample), defined according to different criteria, into a graph. Later, we project the generated graph into an induced vector space, creating fusion vectors, targeting broader generality and efficiency. A fusion vector estimator is then built to infer whether a multimodal input object refers to a class or not. Our method is capable of promoting a fusion model better than early-fusion and late-fusion alternatives. Performed experiments in the context of multiple multimodal and visual datasets, as well as several descriptors and retrieval models, demonstrate that our learning model is highly effective for different prediction scenarios involving visual, textual, and multimodal features, yielding better effectiveness than state-of-the-art methods

A educação para o desenvolvimento sustentável nos ensinos básico e superior

Mestrado em Ensino do 1º e do 2º Ciclo do Ensino BásicoO planeta Terra enfrenta, atualmente, uma situação de autêntica emergência planetária. Sabe-se que o crescimento demográfico é uma das suas principais causas e a qual acaba por agravar, de forma séria, muitas outros problemas do planeta Terra como por exemplo, a perda de diversidade biológica e cultural, a exploração abusiva dos recursos, o fenómeno do aquecimento global e os conflitos destrutivos provocados pelo Homem. Decorrente destes, nunca hoje o impacto da espécie humana foi tão elevado, dado que chega ao ponto de interferir com os sistemas globais da Terra (por exemplo, através das elevadas emissões de gases que provocam o efeito de estufa), alterando ecossistemas a uma velocidade nunca antes vista na história do Homem. É neste contexto, e reconhecendo que a educação é uma ferramenta essencial para a promoção de competências de vida sustentáveis, que surge o conceito de “Educação para o Desenvolvimento Sustentável” – EDS. Este ganhou destaque internacional através da proclamação, por parte da UNESCO, da Década da Educação para o Desenvolvimento Sustentável e, num processo dinâmico, interativo e participativo, visa a formação integral das pessoas, com vista à compreensão e consciencialização dos problemas e desigualdades que a sociedade atual enfrenta. Face à crise atual do planeta Terra e à importância da EDS para alterar paradigmas de vida insustentáveis, a presente investigação procurou averiguar se esta abordagem está a ser contemplada quer no 2.º Ciclo do Ensino Básico – procurando referências explícitas nas Metas Curriculares –, quer no Ensino Superior – centrada numa Universidade Pública Portuguesa (Universidade de Aveiro) – e procurando referências explícitas na descrição online das unidades curriculares dessa instituição. O percurso da investigação, de natureza qualitativa, foi dividido em três fases e teve um design de estudo de caso de caráter exploratório, múltiplo e coletivo, dado que se analisam duas realidades (ensinos básico e superior) sobre as quais se conhece pouco (o que não invalida que se possam prever resultados semelhantes). Na fase um filtraram-se, com suporte técnico e com recurso ao instrumento de análise previamente concebido e validado (lista de expressões-chave que remetem para a EDS), as unidades curriculares da referida universidade que possuíam referências explícitas e analisaram-se as suas descrições, a partir do seu website. De seguida, na fase dois, descreveu-se em que componentes se verifica a presença da EDS. Por fim, na fase três, concebeu-se uma proposta de Metas Curriculares de Ciências Naturais para o 2.º Ciclo do Ensino Básico (5.º ano), orientadas sob o ponto de vista da EDS. A título de exemplo, elucida-se que a pesquisa referida na fase um obteve apenas 15 correspondências e, das 87 unidades curriculares analisadas, dos mestrados profissionalizantes para a docência, apenas nove possuem referências explícitas às expressões-chave do instrumento de análise utilizado. Resultante da análise e discussão dos dados obtidos, o presente trabalho evidencia que as referências explícitas a EDS são ainda escassas e expõe uma proposta de Metas Curriculares para o 2º CEB em que esta abordagem educacional aparece de forma mais evidente. Uma implicação deste estudo tem a ver com a necessidade de formação de Professores, quer do Ensino Superior, quer do Ensino Básico, no que se refere à EDS.Our planet Earth faces, nowadays, a real planetary emergency situation. It is known that demographic growth is one of the main responsible causes for this situation and which ends up worsen, severely, many other Earth’s problems like, for instance, loss of biological and cultural biodiversity, abuse of natural resources, global warming and the destructive conflicts caused by the human being. Due to this factor, the impact of the human species has never been greater than it currently is, since it actually interferes with the global systems of Earth (for example, with the high emissions of greenhouse gases to the atmosphere), changing ecosystems at a never seen before in the Human history speed). It’s in this context, and accrediting that education is an essential tool to promote sustainable life competences, that the concept of “Education for Sustainable Development” – ESD – emerges. It has gained international prominence with the Decade of Education for Sustainable Development promulgation by UNESCO. It’s an approach that aims to the comprehensive training of people for the understanding and awareness of the problems and inequalities that the current society faces, using a dynamic, interactive and participatory process. Given the actual planet crisis and the ESD importance to change the current unbearable paradigms of life, the present investigation tried to ascertain if this approach is being contemplated either in the 2nd cycle of basic education – searching for explicit references in the curricular goals –, either in the higher education – using a Portuguese Public University (Aveiro’s University) as a sample and looking for explicit references in the institution’s courses online description. The research route of this qualitative investigation was split in three phases and had the principles of a case study with exploratory, multiple and collective features, since two realities (Basic and Higher Education), on which little is known – what doesn’t disable the hypothesis that the results will be similar – were analysed. In phase one, the courses were filtrated, using technical support and a previously designed and validated analytical tool (consisting in a list of key expressions that refer to ESD), and theirs online description was analysed. In addition to these, all the professional master for teaching courses and the curricular goals of natural sciences for the 2nd cycle of basic education goals were also scrutinized. Then, in phase two, it was described in which component, of the courses and curricular goals, were the explicit references to ESD. Finally, at phase three, a curricular goals of natural sciences for the 2nd cycle of basic education (5th grade) proposal, oriented from the ESD point of view, was conceived. It’s important to emphasize that phase one’s filtering had only 15 matches and, from the 87 analysed courses, only nine had explicit references to the analytical tool’s key expressions. From the data analysis and discussion, it’s plausible to say that this investigation highlights that the clear allusions to ESD are yet scarce. The document also exposes and suggests a curricular goals proposal in which the approach in case appears more clearly. An implication of this investigation is related with the necessity of teachers training, whether in Higher or in Basic Education, as regards to ESD

Design and Evaluation of Techniques to Utilize Implicit Rating Data in Complex Information Systems.

Research in personalization, including recommender systems, focuses on applications such as in online shopping malls and simple information systems. These systems consider user profile and item information obtained from data explicitly entered by users - where it is possible to classify items involved and to make personalization based on a direct mapping from user or user group to item or item group. However, in complex, dynamic, and professional information systems, such as Digital Libraries, additional capabilities are needed to achieve personalization to support their distinctive features: large numbers of digital objects, dynamic updates, sparse rating data, biased rating data on specific items, and challenges in getting explicit rating data from users. In this report, we present techniques for collecting, storing, processing, and utilizing implicit rating data of Digital Libraries for analysis and decision support. We present our pilot study to find virtual user groups using implicit rating data. We demonstrate the effectiveness of implicit rating data for characterizing users and finding virtual user communities, through statistical hypothesis testing. Further, we describe a visual data mining tool named VUDM (Visual User model Data Mining tool) that utilizes implicit rating data. We provide the results of formative evaluation of VUDM and discuss the problems raised and plans for further studies

Leafing patterns and drivers across seasonally dry tropical communities

Investigating the timing of key phenological events across environments with variable seasonality is crucial to understand the drivers of ecosystem dynamics. Leaf production in the tropics is mainly constrained by water and light availability. Identifying the factors regulating leaf phenology patterns allows efficiently forecasting of climate change impacts. We conducted a novel phenological monitoring study across four Neotropical vegetation sites using leaf phenology time series obtained from digital repeated photographs (phenocameras). Seasonality differed among sites, from very seasonally dry climate in the caatinga dry scrubland with an eight-month long dry season to the less restrictive Cerrado vegetation with a six-month dry season. To unravel the main drivers of leaf phenology and understand how they influence seasonal dynamics (represented by the green color channel (Gcc) vegetation index), we applied Generalized Additive Mixed Models (GAMMs) to estimate the growing seasons, using water deficit and day length as covariates. Our results indicated that plant-water relationships are more important in the caatinga, while light (measured as day-length) was more relevant in explaining leafing patterns in Cerrado communities. Leafing behaviors and predictor-response relationships (distinct smooth functions) were more variable at the less seasonal Cerrado sites, suggesting that different life-forms (grasses, herbs, shrubs, and trees) are capable of overcoming drought through specific phenological strategies and associated functional traits, such as deep root systems in trees

Eruca sativa plants modulate growth and gas exchange when cultivated under salinity stress after leaching fractions

The physiology of rocket plants at different salinity levels through irrigation water and leaching fractions was assessed. Four salinity levels of irrigation water: 0.10, 1.60, 3.10 and 4.60 dS m-1 and three leaching fractions: 0, 10 and 20% were applied. The physiological variables analyzed were photosynthetic rate, stomatal conductance, transpiration rate and photosynthetic pigment contents. The growth and biomass production were analyzed by: plant height, number of leaves, leaf area and partitioned and total plant fresh and dry mass, and root to aerial part ratio. The leaching fraction of 10% combined with irrigation with water salinity levels ranging from 0.10 to 0.88 dS m-1 resulted in greater plant height, leaf area and root, shoot and total dry mass. The leaching fraction of 20% with irrigation water with salinity levels from 0.10 to 2.7 dS m-1 generates higher leaf number, shoot fresh mass, root-to-shoot ratio, stomatal conductance, and photosynthetic rate. Irrigation water with a salinity level of 0.10 dS m-1 provides a higher transpiration rate for rocket plants. Irrigation water with a salinity level of 4.6 dS m-1 generates higher chlorophyll a, b and total (a + b) and carotenoid contents in rocket plants

CHEMICAL FERTILIZATION THROUGH FERTIRRIGATION IN THE EVALUATION OF THE BIOCHEMICAL CHARACTERISTICS OF THE WATERMELON FRUITS

The objective of this work was to evaluate the effects of splitting in three different doses of phosphorus and potassium, combined with each other, and it was applied fertirrigation in watermelon crop, and to evaluate their effects on fruit quality. The statistical was in a complete randomized block design, and the treatments were arranged in a factorial scheme (3 x 3) in subdivided splits, resulting in 9 treatments with tree replications, totaling 27 plots in the experimental area. In the horizontal plots the three doses of phosphorus fertilization (100, 150 and 300 kg.ha-1 of P2O5) were randomly allocated, and in the subplots the three potassium doses (50, 100 and 200 kg.ha-1 of K2O), were applied in fertirrigation. The cultivar used was Crimson Sweet. Seventy-Six days after planting (DAP) the biochemical characteristics of watermelon fruits were evaluated: total soluble solids (TSS), total treatable acidity (TTA) and potential of hydrogen (pH). According to the results, it was verified that only the chemical value of the TSS fruits, presented significant statistical differences between the studied doses because of the different source of fertilization K and P increased the soluble solid contents, the content of reducing sugars, and decreased pH. It was observed the different doses of K and P did not influence in the fruit quality parameters when it was analyzed separated: TTA and pH but the TTA values are according to consumer market standards. The best doses in order to economy of fertilizer were (150 kg ha-1 de P2O5 e 50 kg ha-1 of K2O)