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About

José Machado da Silva obtained a PhD degree on electrical and computer engineering in 1998 and is currently an Associated Professor at the Faculty of Engineering of the University of Porto, and a Senior Researcher at INESC Porto. His teaching and research interests include analogue, mixed-signal, and RF VLSI design and test, signal processing, and biomedical electronics.

Interest
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Details

Details

006
Publications

2020

Biot-granier sensor: A novel strategy to measuring sap flow in trees

Authors
Siqueira, JM; Paco, TA; da Silva, JM; Silvestre, JC;

Publication
Sensors (Switzerland)

Abstract
The Biot-Granier (Gbt) is a new thermal dissipation-based sap flow measurement methodology, comprising sensors, data management and automatic data processing. It relies on the conventional Granier (Gcv) methodology upgraded with a modified Granier sensor set, as well as on an algorithm to measure the absolute temperatures in the two observation points and perform the Biot number approach. The work described herein addresses the construction details of the Gbt sensors and the characterization of the overall performance of the Gbt method after comparison with a commercial sap flow sensor and independent data (i.e., volumetric water content, vapor pressure deficit and eddy covariance technique). Its performance was evaluated in three trials: potted olive trees in a greenhouse and two vineyards. The trial with olive trees in a greenhouse showed that the transpiration measures provided by the Gbt sensors showed better agreement with the gravimetric approach, compared to those provided by the Gcv sensors. These tended to overestimate sap flow rates as much as 4 times, while Gbt sensors overestimated gravimetric values 1.5 times. The adjustments based on the Biot equations obtained with Gbt sensors contribute to reduce the overestimates yielded by the conventional approach. On the other hand, the heating capacity of the Gbt sensor provided a minimum of around 7? C and maximum about 9? C, contrasting with a minimum around 6? C and a maximum of 12? C given by the Gcv sensors. The positioning of the temperature sensor on the tip of the sap flow needle proposed in the Gbt sensors, closer to the sap measurement spot, allow to capture sap induced temperature variations more accurately. This explains the higher resolution and sensitivity of the Gbt sensor. Overall, the alternative Biot approach showed a significant improvement in sap flow estimations, contributing to adjust the Granier sap flow index, a vulnerability of that methodology. © 2020 by the authors. Licensee MDPI, Basel, Switzerland.

2019

Wearable sensor networks for human gait

Authors
Machado da Silva, J; Derogarian, F; Canas Ferreira, J; Grade Tavares, V;

Publication
Wearable Technologies and Wireless Body Sensor Networks for Healthcare

Abstract

2019

A precise low power and hardware-efficient time synchronization method for wearable systems

Authors
Derogarian, F; Canas Ferreira, J; Grade Tavares, V; Machado da Silva, J; Velez, FJ;

Publication
Wearable Technologies and Wireless Body Sensor Networks for Healthcare

Abstract

2019

A reliable wearable system for BAN applications with a high number of sensors and high data rate

Authors
Derogarian, F; Canas Ferreira, J; Grade Tavares, V; Machado da Silva, J; Velez, FJ;

Publication
Wearable Technologies and Wireless Body Sensor Networks for Healthcare

Abstract

2019

Literature on Wearable Technology for Connected Health: Scoping Review of Research Trends, Advances, and Barriers

Authors
Loncar Turukalo, T; Zdravevski, E; da Silva, JM; Chouvarda, I; Trajkovik, V;

Publication
JOURNAL OF MEDICAL INTERNET RESEARCH

Abstract
Background: Wearable sensing and information and communication technologies are key enablers driving the transformation of health care delivery toward a new model of connected health (CH) care. The advances in wearable technologies in the last decade are evidenced in a plethora of original articles, patent documentation, and focused systematic reviews. Although technological innovations continuously respond to emerging challenges and technology availability further supports the evolution of CH solutions, the widespread adoption of wearables remains hindered. Objective: This study aimed to scope the scientific literature in the field of pervasive wearable health monitoring in the time interval from January 2010 to February 2019 with respect to four important pillars: technology, safety and security, prescriptive insight, and user-related concerns. The purpose of this study was multifold: identification of (1) trends and milestones that have driven research in wearable technology in the last decade, (2) concerns and barriers from technology and user perspective, and (3) trends in the research literature addressing these issues. Methods: This study followed the scoping review methodology to identify and process the available literature. As the scope surpasses the possibilities of manual search, we relied on the natural language processing tool kit to ensure an efficient and exhaustive search of the literature corpus in three large digital libraries: Institute of Electrical and Electronics Engineers, PubMed, and Springer. The search was based on the keywords and properties to be found in articles using the search engines of the digital libraries. Results: The annual number of publications in all segments of research on wearable technology shows an increasing trend from 2010 to February 2019. The technology-related topics dominated in the number of contributions, followed by research on information delivery, safety, and security, whereas user-related concerns were the topic least addressed. The literature corpus evidences milestones in sensor technology (miniaturization and placement), communication architectures and fifth generation (5G) cellular network technology, data analytics, and evolution of cloud and edge computing architectures. The research lag in battery technology makes energy efficiency a relevant consideration in the design of both sensors and network architectures with computational offloading. The most addressed user-related concerns were (technology) acceptance and privacy, whereas research gaps indicate that more efforts should be invested into formalizing clear use cases with timely and valuable feedback and prescriptive recommendations. Conclusions: This study confirms that applications of wearable technology in the CH domain are becoming mature and established as a scientific domain The current research should bring progress to sustainable delivery of valuable recommendations, enforcement of privacy by design, energy-efficient pervasive sensing, seamless monitoring, and low-latency 5G communications. To complement technology achievements, future work involving all stakeholders providing research evidence on improved care pathways and cost-effectiveness of the CH model is needed.

Supervised
thesis

2019

Direct Stimulation for Ligament Regeneration

Author
Raquel Sofia Remoaldo Vaz

Institution
UP-FEUP

2019

A Wearable System for Remote Cardiorespiratory Fitness Monitoring

Author
Marisa Alexandra Pinto Alves

Institution
UP-FEUP

2018

Sistema de Controlo Inferencial com Dispositivos Sensoriais Direcionados para o Uso Eficiente da Água na Agricultura

Author
JUCILENE DE MEDEIROS SIQUEIRA

Institution
IES_Outra

2018

Perspetivas de Desenvolvimento em Saúde Interligada – Aplicação para Gestão de Dados de Pacientes em Zonas Remotas

Author
Osvaldo Banild da Silva Avelino

Institution
UP-FEUP

2018

Monitoring of Health by Means of Saliva Testing

Author
Bárbara Marques

Institution
UP-FEUP