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Publications

2016

Wavelet-Based Visible and Infrared Image Fusion: A Comparative Study

Authors
Sappa, AD; Carvajal, JA; Aguilera, CA; Oliveira, M; Romero, D; Vintimilla, BX;

Publication
SENSORS

Abstract
This paper evaluates different wavelet-based cross-spectral image fusion strategies adopted to merge visible and infrared images. The objective is to find the best setup independently of the evaluation metric used to measure the performance. Quantitative performance results are obtained with state of the art approaches together with adaptations proposed in the current work. The options evaluated in the current work result from the combination of different setups in the wavelet image decomposition stage together with different fusion strategies for the final merging stage that generates the resulting representation. Most of the approaches evaluate results according to the application for which they are intended for. Sometimes a human observer is selected to judge the quality of the obtained results. In the current work, quantitative values are considered in order to find correlations between setups and performance of obtained results; these correlations can be used to define a criteria for selecting the best fusion strategy for a given pair of cross-spectral images. The whole procedure is evaluated with a large set of correctly registered visible and infrared image pairs, including both Near InfraRed (NIR) and Long Wave InfraRed (LWIR).

2016

Effects of hypergravity on the angiogenic potential of endothelial cells

Authors
Costa Almeida, R; Carvalho, DTO; Ferreira, MJS; Aresta, G; Gomes, ME; van Loon, JJWA; Van der Heiden, K; Granja, PL;

Publication
JOURNAL OF THE ROYAL SOCIETY INTERFACE

Abstract
Angiogenesis, the formation of blood vessels from pre-existing ones, is a key event in pathology, including cancer progression, but also in homeostasis and regeneration. As the phenotype of endothelial cells (ECs) is continuously regulated by local biomechanical forces, studying endothelial behaviour in altered gravity might contribute to new insights towards angiogenesis modulation. This study aimed at characterizing EC behaviour after hypergravity exposure (more than 1g), with special focus on cytoskeleton architecture and capillary-like structure formation. Herein, human umbilical vein ECs (HUVECs) were cultured under two-dimensional and three-dimensional conditions at 3g and 10g for 4 and 16 h inside the large diameter centrifuge at the European Space Research and Technology Centre (ESTEC) of the European Space Agency. Although no significant tendency regarding cytoskeleton organization was observed for cells exposed to high g's, a slight loss of the perinuclear localization of beta-tubulin was observed for cells exposed to 3g with less pronounced peripheral bodies of actin when compared with 1g control cells. Additionally, hypergravity exposure decreased the assembly of HUVECs into capillary-like structures, with a 10g level significantly reducing their organization capacity. In conclusion, short-term hypergravity seems to affect EC phenotype and their angiogenic potential in a time and g-level-dependent manner.

2016

Improving Human Activity Classification through Online Semi-Supervised Learning

Authors
Cardoso, HL; Moreira, JM;

Publication
Proceedings of the Workshop on Large-scale Learning from Data Streams in Evolving Environments (STREAMEVOLV 2016) co-located with the 2016 European Conference on Machine Learning and Principles and Practice of Knowledge Discovery in Databases (ECML/PKDD 2016), Riva del Garda, Italy, September 23, 2016.

Abstract
Built-in sensors in most modern smartphones open multiple opportunities for novel context-aware applications. Although the Human Activity Recognition field seized such opportunity, many challenges are yet to be addressed, such as the differences in movement by people doing the same activities. This paper exposes empirical research on Online Semi-supervised Learning (OSSL), an under-explored incremental approach capable of adapting the classification model to the user by continuously updating it as data from the user's own input signals arrives. Ultimately, we achieved an average accuracy increase of 0.18 percentage points (PP) resulting in a 82.76% accuracy model with Naive Bayes, 0.14 PP accuracy increase resulting in a 83.03% accuracy model with a Democratic Ensemble, and 0.08 PP accuracy increase resulting in a 84.63% accuracy model with a Confidence Ensemble. These models could detect 3 stationary activities, 3 active activities, and all transitions between the stationary activities, totaling 12 distinct activities.

2016

Typed Connector Families

Authors
Proenca, J; Clarke, D;

Publication
FORMAL ASPECTS OF COMPONENT SOFTWARE

Abstract
Typed models of connector/component composition specify interfaces describing ports of components and connectors. Typing ensures that these ports are plugged together appropriately, so that data can flow out of each output port and into an input port. These interfaces typically consider the direction of data flow and the type of values flowing. Components, connectors, and systems are often parameterised in such a way that the parameters affect the interfaces. Typing such connector families is challenging. This paper takes a first step towards addressing this problem by presenting a calculus of connector families with integer and boolean parameters. The calculus is based on monoidal categories, with a dependent type system that describes the parameterised interfaces of these connectors. As an example, we demonstrate how to define n-ary Reo connectors in the calculus. The paper focusses on the structure of connectors-well-connectedness-and less on their behaviour, making it easily applicable to a wide range of coordination and component-based models. A type-checking algorithm based on constraints is used to analyse connector families, supported by a proof-of-concept implementation.

2016

Operation scheduling of prosumer with renewable energy sources and storage devices

Authors
Souza, SM; Gil, M; Sumaili, J; Madureira, AG; Pecas Lopes, JAP;

Publication
2016 13TH INTERNATIONAL CONFERENCE ON THE EUROPEAN ENERGY MARKET (EEM)

Abstract
The reduction or elimination of incentives for the installation of decentralized generation directly at the customers' premises, favoring self-consumption, can bring significant changes for distribution network operation. According to the new Portuguese law, injection of energy into the distribution grid is discouraged since prosumers receive only 90% of the energy cost in the Iberian Energy Market. In order to lower energy bills, the possibility of storing excess energy is being considered as a possible solution. In this paper, an optimization framework is proposed to model the operation of consumers with renewable-based Distributed Generation (DG) and storage capacity and assess their aggregated effect at the level of the MV grid using a multi-temporal Optimal Power Flow (OPF). The proposed algorithm is then tested in a real Portuguese MV network to evaluate its performance. Finally, a financial viability analysis is performed considering the installation of small PV generators and storage devices at the residential level.

2016

Intelligent energy management using CBR: Brazilian residential consumption scenario

Authors
Fernandes, F; Alves, D; Pinto, T; Takigawa, F; Fernandes, R; Morais, H; Vale, Z; Kagan, N;

Publication
2016 IEEE Symposium Series on Computational Intelligence, SSCI 2016

Abstract
This paper proposes a novel case-based reasoning (CBR) approach to support the intelligent management of energy resources in a residential context. The proposed approach analyzes previous cases of consumption reduction in houses, and determines the amount that should be reduced in each moment and in each context, in order to meet the users' needs in terms of comfort while minimizing the energy bill. The actual energy resources management is executed using the SCADA House Intelligent Management (SHIM) system, which schedules the use of the different resources, taking into account the suggested reduction amount. A case study is presented, using data from Brazilian consumers. Several scenarios are considered, representing different combinations concerning the type of house/inhabitants, the season, the type of used energy tariff, the use of Photovoltaic system (PV) generation, and the maximum amount of allowed reduction. Results show that the proposed CBR approach is able to suggest appropriate amounts of energy reduction, which result in significant reductions of the energy bill, while, with the use of SHIM, minimizing the reduction of users' comfort. © 2016 IEEE.

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