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Publicações

2020

Proof-of-concept study on a wave energy converter based on the roll oscillations of multipurpose offshore floating platforms

Autores
Clemente, D; Rosa Santos, P; Taveira Pinto, F; Martins, P; Paulo Moreira, A;

Publicação
ENERGY CONVERSION AND MANAGEMENT

Abstract
Inspired by observing the motions of vessels at sea, the E-Motions has been proposed as an innovative concept capable of converting wave (and wind) induced roll oscillations on multipurpose offshore floating platforms into electricity. The device can be integrated, theoretically, into any type of offshore floating structure, given its simple 3-component design: floating platform, encasing and sliding Power Take-Off. This latter component can be sheltered from the marine environment by being placed within a casing, at deck level, or the hull of the offshore structure. With so much potential for application at sea, it was important to subject the E-Motions to an initial proof-of-concept, as done for other wave energy converters. This paper presents and discusses the main results and conclusions of an experimental study, carried out with a 1:40 reduced scale physical model, aimed at demonstrating the technical and technological viability of the E-Motions. It was found that, for the considered study variables, the device can operate without major incident and convert electricity from wave induced roll oscillations. Four ballast configurations were considered, of which two yielded higher power outputs. The average measured power reached as high as 11 kW and 13 kW, respectively, with the values reducing for wave period further away from the resonance range and lower wave heights. Power Take-Off damping was found to be an important variable that can considerably influence the energy generation process, yet it will be imperative to further assess this variable in combination with other pertinent variables, such as an external attached mass and different generators. This is key to better understand and describe the complex and non-linear relationship between the motions of the Power Take-Off and the floating platform components.

2020

BESS modeling: investigating the role of auxiliary system consumption in efficiency derating

Autores
Rancilio, G; Merlo, M; Lucas, A; Kotsakis, E; Delfanti, M;

Publicação
2020 International Symposium on Power Electronics, Electrical Drives, Automation and Motion (SPEEDAM)

Abstract

2020

HORUS: An Emotion Recognition Tool

Autores
Teixeira, A; Rodrigues, M; Carneiro, D; Novais, P;

Publicação
INTELLIGENT SYSTEMS AND APPLICATIONS, VOL 1

Abstract
Emotion is an essential part of what means to be human, but it is still disregarded by most technical fields as something not to be considered in scientific or engineering projects. However, the understanding of emotion as an aspect of decision-making processes and of modelling of human behavior is essential to create a better connection between humans and their tools and machines. With this work we focus on the measurement of emotion of users through the use of non-intrusive methods, like measuring inputs and reactions to stimuli, along with the creation of a tool that measures the emotional changes caused by visual output created by the tool itself. Usage of the tool in a test environment and the subsequent analysis of the data obtained will allow for conclusions about the effectiveness of the method, and if it is possible to apply it to future studies on human emotions by investigators in the fields of psychology and computation.

2020

Tightening Up Security In Low Power Deterministic Networks

Autores
Tiberti, W; Vieira, B; Kurunathan, H; Severino, R; Tovar, E;

Publicação
16th IEEE International Conference on Factory Communication Systems, WFCS 2020, Porto, Portugal, April 27-29, 2020

Abstract
The unprecedented pervasiveness of IoT systems is pushing this technology into increasingly stringent domains. Such application scenarios become even more challenging due to the demand for encompassing the interplay between safety and security. The IEEE 802.15.4 DSME MAC behavior aims at addressing such systems by providing additional deterministic, synchronous multi-channel access support. However, despite the several improvements over the previous versions of the protocol, the standard lacks a complete solution to secure communications. In this front, we propose the integration of TAKS, an hybrid cryptography scheme, over a standard DSME network. In this paper, we describe the system architecture for integrating TAKS into DSME with minimum impact to the standard, and we venture into analysing the overhead of having such security solution over application delay and throughput. After a performance analysis, we learn that it is possible to achieve a minor impact of 1% to 14% on top of the expected network delay, depending on the platform used, while still guaranteeing strong security support over the DSME network. © 2020 IEEE.

2020

CAN Based Network for Modular Battery Bank with Security Features

Autores
Marques, L; Silva, M; Vasconcelos, V;

Publicação
2020 15TH IBERIAN CONFERENCE ON INFORMATION SYSTEMS AND TECHNOLOGIES (CISTI'2020)

Abstract
Energy storage in electric vehicles and homes can be obtained by the use of batteries, being Lithium based cells common nowadays. These batteries need a close control for evaluating namely its state-of-charge, to use as efficiently as possible the stored energy, ensuring an operational safe use of the battery bank. This article presents a modular battery bank, composed of modules of four lithium cells each, focusing on the communication network that is based on CAN, which controls its charge and discharge and produces alarms for diverse conditions. As this network is connected to the global vehicle or home network, some security measures are discussed, as internal or external attacks can happen that can hinder or even interrupt the energy supply, which can constitute a severe major hazard.

2020

Black-box inter-application traffic monitoring for adaptive container placement

Autores
Neves, F; Vilaca, R; Pereira, J;

Publicação
PROCEEDINGS OF THE 35TH ANNUAL ACM SYMPOSIUM ON APPLIED COMPUTING (SAC'20)

Abstract
A key issue in the performance of modern containerized distributed systems, such as big data storage and processing stacks or micro service based applications, is the placement of each container, or container pod, in virtual and physical servers. Although it has been shown that inter-application traffic is an important factor in placement decisions, as it directly indicates how components interact, it has not been possible to accurately monitor it in an application independent way, thus putting it out of reach of cloud platforms. In this paper we present an efficient black-box monitoring approach for detecting and building a weighted communication graph of collaborating processes in a distributed system that can be queried for various purposes, including adaptive placement. The key to achieving high detail and low overhead without custom application instrumentation is to use a kernel-aided event driven strategy. We evaluate a prototype implementation with micro-benchmarks and demonstrate its usefulness for container placement in a distributed data storage and processing stack (i.e., Cassandra and Spark).

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