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Publicações

2019

d'Artagnan: A Trusted NoSQL Database on Untrusted Clouds

Autores
Pontes, R; Maia, F; Vilaça, R; Machado, N;

Publicação
SRDS

Abstract
Privacy sensitive applications that store confidential information such as personal identifiable data or medical records have strict security concerns. These concerns hinder the adoption of the cloud. With cloud providers under the constant threat of malicious attacks, a single successful breach is sufficient to exploit any valuable information and disclose sensitive data. Existing privacy-aware databases mitigate some of these concerns, but sill leak critical information that can potently compromise the entire system's security. This paper proposes d'Artagnan, the first privacy-aware multi-cloud NoSQL database framework that renders database leaks worthless. The framework stores data as encrypted secrets in multiple clouds such that i) a single data breach cannot break the database's confidentiality and ii) queries are processed on the server-side without leaking any sensitive information. d'Artagnan is evaluated with industry-standard benchmark on market-leading cloud providers.

2019

Multimodal narratives as a tool for in-service teachers in an online professional development course

Autores
Pedrosa, D; Cruz, G; Morgado, L;

Publicação
Multimodal Narratives in Research and Teaching Practices

Abstract
This chapter presents how multimodal narratives were employed as a self-reflection tool within an online professional development program for in-service teacher training at Universidade Aberta, Portugal during two editions of a pedagogic practice course. The chapter includes the aspects that raised issues and those that trainees performed correctly. This is done in three stages: beforehand, upon initial contact with multimodal narratives, and after providing feedback to trainees. The most relevant issues were in aspects directly required to enrich the narrative. Aspects related to multimodal narrative structure and features were completed successfully. It is recommended that future attempts to employ multimodal narratives in this context adapt learning resources and pedagogic support practices by employing formative feedback and continual support during the trainees' process of exploring and exploiting multimodal narratives. © 2019, IGI Global.

2019

UNCERTAINTY-AWARE ARTERY/VEIN CLASSIFICATION ON RETINAL IMAGES

Autores
Galdran, A; Meyer, M; Costa, P; Mendonça; Campilho, A;

Publicação
2019 IEEE 16TH INTERNATIONAL SYMPOSIUM ON BIOMEDICAL IMAGING (ISBI 2019)

Abstract
The automatic differentiation of retinal vessels into arteries and veins (A/V) is a highly relevant task within the field of retinal image analysis. however, due to limitations of retinal image acquisition devices, specialists can find it impossible to label certain vessels in eye fundus images. In this paper, we introduce a method that takes into account such uncertainty by design. For this, we formulate the A/V classification task as a four-class segmentation problem, and a Convolutional Neural Network is trained to classify pixels into background, A/V, or uncertain classes. The resulting technique can directly provide pixelwise uncertainty estimates. In addition, instead of depending on a previously available vessel segmentation, the method automatically segments the vessel tree. Experimental results show a performance comparable or superior to several recent A/V classification approaches. In addition, the proposed technique also attains state-of-the-art performance when evaluated for the task of vessel segmentation, generalizing to data that, was not used during training, even with considerable differences in terms of appearance and resolution.

2019

MULTI-PURPOSE CHESTNUT CLUSTERS DETECTION USING DEEP LEARNING: A PRELIMINARY APPROACH

Autores
Adao, T; Pádua, L; Pinho, TM; Hruska, J; Sousa, A; Sousa, JJ; Morais, R; Peres, E;

Publicação
ISPRS ICWG III/IVA GI4DM 2019 - GEOINFORMATION FOR DISASTER MANAGEMENT

Abstract
In the early 1980's, the European chestnut tree (Castanea sativa, Mill.) assumed an important role in the Portuguese economy. Currently, the Trás-os-Montes region (Northeast of Portugal) concentrates the highest chestnuts production in Portugal, representing the major source of income in the region (€50M-€60M). The recognition of the quality of the Portuguese chestnut varieties has increasing the international demand for both industry and consumer-grade segments. As result, chestnut cultivation intensification has been witnessed, in such a way that widely disseminated monoculture practices are currently increasing environmental disaster risks. Depending on the dynamics of the location of interest, monocultures may lead to desertification and soil degradation even if it encompasses multiple causes and a whole range of consequences or impacts. In Trás-os-Montes, despite the strong increase in the cultivation area, phytosanitary problems, such as the chestnut ink disease (Phytophthora cinnamomi) and the chestnut blight (Cryphonectria parasitica), along with other threats, e.g. chestnut gall wasp (Dryocosmus kuriphilus) and nutritional deficiencies, are responsible for a significant decline of chestnut trees, with a real impact on production. The intensification of inappropriate agricultural practices also favours the onset of phytosanitary problems. Moreover, chestnut trees management and monitoring generally rely on in-field time-consuming and laborious observation campaigns. To mitigate the associated risks, it is crucial to establish an effective management and monitoring process to ensure crop cultivation sustainability, preventing at the same time risks of desertification and land degradation. Therefore, this study presents an automatic method that allows to perform chestnut clusters identification, a key-enabling task towards the achievement of important goals such as production estimation and multi-temporal crop evaluation. The proposed methodology consists in the use of Convolutional Neural Networks (CNNs) to classify and segment the chestnut fruits, considering a small dataset acquired based on digital terrestrial camera. © 2019 International Society for Photogrammetry and Remote Sensing.

2019

Wireless visual sensor networks redeployment based on dependability optimization

Autores
Jesus, TC; Costa, DG; Portugal, P;

Publicação
2019 IEEE 17TH INTERNATIONAL CONFERENCE ON INDUSTRIAL INFORMATICS (INDIN)

Abstract
Wireless visual sensor networks (WVSN) bring a more comprehensive perception of monitored environments, leading to an increase adoption of such networks as a promising solution for a wide range of applications. Among many examples, highlight industrial applications related to the industry 4.0 paradigm, which increasingly require more data from manufacturing systems. Those sensor-based applications are in many cases safety-critical, requiring dependability guarantees mainly related with reliability and availability, that should be maintained during the whole network operation. Although several approaches have provided network deployment with dependability guarantees, sometimes the monitored environment or the application configurations can change during the network operation, which can violate the dependability requirements and demand network redeployment in order to keep those guarantees. In this paper we propose a novel algorithm to redeploy WVSN guided by the optimization of the application dependability, considering changes on cameras' orientations. A methodology is defined to support dependability analysis. We compare the results of the proposed algorithm with previous algorithms found in literature. The achieved results show that the proposed algorithm is useful and efficient to provide network redeployment, keeping or improving the application dependability.

2019

Power Transmitter Design for Underwater WPT

Autores
Silva, M; Duarte, C; Goncalves, F; Correia, V; Pessoa, L;

Publicação
OCEANS 2019 - Marseille

Abstract

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