Hugo Plácido da Silva

Institute of Telecommunications | IT · Group of Pattern and Image Analysis

Introduction We developed Eforto®, an innovative system for (self-)monitoring of grip strength (GS) and muscle fatigability (Fatigue Resistance (FR = time until GS decreased to 50% of maximum during sustained contraction) and grip work (GW = area under the strength-time curve)). The Eforto® system consists of a rubber bulb that is wirelessly connec...

Engineered feature extraction can compromise the ability of Atrial Fibrillation (AFib) detection algorithms to deliver near real-time results. Autoencoders (AEs) can be used as an automatic feature extraction tool, tailoring the resulting features to a specific classification task. By coupling an encoder to a classifier, it is possible to reduce th...

With the increasing number of devices that we have available to monitor our health, the conditions in which the measurements are done are no longercontrolled environments. Apart from all the motion artifacts that may affect the biosignal, the acquisition system itself, being an electronic equipment, issubject to electromagnetic interferences which...

When long-term biosignal monitoring is required via surface electrodes, the use of conventional silver/silver chloride (Ag/AgCl) gelled electrodes may not be the best solution, as the gel in the electrodes tends to dry out over time. In this work, the electrical behaviour and performance of dry electrodes for biopotential monitoring was assessed. T...

In recent years, employment in sedentary occupations has continuously risen. Office workers are more prone to prolonged static sitting, spending 65–80% of work hours sitting, increasing risks for multiple health problems, including cardiovascular diseases and musculoskeletal disorders. These adverse health effects lead to decreased productivity, in...

Wearable devices have been shown to play an important role in disease prevention and health management, through the multimodal acquisition of peripheral biosignals. However, many of these wearables are exposed, limiting their long-term acceptability by some user groups. To overcome this, a wearable smart sock integrating a PPG sensor and an EDA sen...

This book constitutes selected papers of the Fourth International Conference on Computer-Human Interaction Research and Applications, CHIRA 2020, held virtually, in November 2020. The 8 full papers presented in this book were carefully reviewed and selected from 44 submissions. The papers selected to be included in this book contribute to the under...

Depressive disorders are a leading cause of morbility and disability in the working population worldwide. Psychiatric assessment and treatment of depressive disorders may be improved by using objective behavioral and physiological biomarkers. In this work we present a psychiatry telemedicine platform where two important biomarkers of depression, ey...

AI-based software applications for personalized nutrition have recently gained increasing attention to help users follow a healthy lifestyle. In this paper, we present a knowledge-based recommendation framework that exploits an explicit dataset of expert-validated meals to offer highly accurate diet plans spanning across ten user groups of both hea...

The fused deposition modelling technique has been used in the production of strain sensors in which fibre Bragg gratings (FBGs) are encapsulated during the 3D printing process. This paper reports the study of the influence of the FBG position and the material filling, in this case a flexible polymer material, on the sensors’ sensitivity and overall...

Acting emotions refers to the actor's ability to perform a character's emotions as his/her own emotions and deliver them to the public. We designed an experimental protocol to investigate the physiological correlates of emotional valence and arousal (V-A) within 11 theatre actors (36 years average). We analysed continuous annotation trajectories an...

Heart sound recordings are a key non-invasive tool to detect both congenital and acquired heart conditions. As part of the George B. Moody PhysioNet Challenge 2022, we present an approach based on Bidirectional Long Short-Term Memory (BiLSTM) neural networks for the detection of murmurs and prediction of clinical outcome from Phonocardiograms (PCGs...

Electrodermal activity (EDA) is a low-cost and nonintrusive way of monitoring the emotional state of a subject. It is also a viable gateway to study the sympathetic nervous system (SNS), which is responsible for the so-called fight-or-flight responses happening at the unconsciousness level (Boucsein, 2012).

Rehabilitation treatments have been greatly en-hanced by health-enabling technologies, as these enable more objective and interactive interventions. Multiple studiesindi-cate that gamification is efficient in promoting treatment cus-tomization, adherence, motivation, and engagement, leading to increased patient satisfaction. In this work we study t...

Within the field of movement sensing and sound interaction research, multi-user systems have gradually gained interest as a means to facilitate an expressive non-verbal dialogue. When tied with studies grounded in psychology and choreographic theory, we consider the qualities of interaction that foster an elevated sense of social connectedness, non...

Within the field of movement sensing and sound interaction research, multi-user systems have gradually gained interest as a means to facilitate an expressive non-verbal dialogue. When tied with studies grounded in psychology and choreographic theory, we consider the qualities of interaction that foster an elevated sense of social connectedness, non...

Several studies have been showing radars as promising contactless vital signs monitoring tools, with IR-UWB and FMCW, being the most popular radar architectures implemented for vital signs remote sensing applications. However, most of the studies focus on developing algorithms for processing data extracted from one only type of radar and consequent...

This article proposes a new method of identity recognition in sanitary facilities based on electrocardiography (ECG) signals. Our team previously proposed a novel approach of invisible ECG at the thighs using polymeric electrodes, leading to the creation of a proof-of-concept system integrated into a toilet seat. In this work, a biometrics pipeline...

Professional theatre actors are highly specialized in controlling their own expressive behaviour and non-verbal emotional expressiveness, so they are of particular interest in fields of study such as affective computing. We present Acting Emotions, an experimental protocol to investigate the physiological correlates of emotional valence and arousal...

Wearable sensors have increasingly been applied in healthcare to generate data and monitor patients unobtrusively. Their application for Brain–Computer Interfaces (BCI) allows for unobtrusively monitoring one’s cognitive state over time. A particular state relevant in multiple domains is cognitive fatigue, which may impact performance and attention...

Within the field of movement sensing and sound interaction research, multi-user systems have gradually gained interest as a means to facilitate an expressive non-verbal dialogue. When tied with studies grounded in psychology and choreographic theory, we consider the qualities of interaction that foster an elevated sense of social connectedness, non...

Biosignals represent a first-line source of information to understand the behavior and state of human biological systems, often used in machine learning problems. However, the development of healthcare-related algorithms that are both personalized and robust requires the collection of large volumes of data to capture representative instances of all...

The availability of low-cost biomedical devices has driven a growing interest in the use of physiological signals for mental and emotional health research. Due to their potential for integration in discrete wearable form factors, Photoplethysmography (PPG) and Electrodermal Activity (EDA) are particularly popular, especially in out-of-the-lab exper...

In the latter years, we have been observing a growth in wearable technology for personal use. However, an analysis of the state of the art for wearable technology shows that most devices perform data acquisition from individual subjects only, relying on communication technologies with drawbacks that prevent their use in collective real-world scenar...

Around the world, about 50 million people suffer from epilepsy, a disease characterised by recurrent and unprovoked seizures of abrupt cerebral activity. Epileptic seizures require a thorough diagnosis and follow-up for long and frequent hospitalisations, which demand a heavy workload to the clinical teams. It has been suggested that these studies...

This work proposes an optical sensing network to monitor pressure and temperature in specific areas of a wheelchair to prevent pressure ulcers and to monitor the position of the wheelchair user by analyzing its pressure distribution. The sensing network is composed of six optical fiber Bragg grating (FBG)-based sensor cells. Each sensor cell is bui...

This work proposes a 3D-printed sensor based on fiber Bragg grating (FBG) technology for respiratory rate (RR) and heart rate (HR) monitoring. Each sensor is composed of a single FBG fully encapsulated into a 3D-printable Flexible, during the printing process. Sensors with different material thicknesses and infill densities were tested. The sensor...

The development of mobile health for epilepsy has grown in the last years, bringing new applications (apps) to the market and improving already existing ones. In this systematic review, we analyse the scope of mobile apps for seizure detection and epilepsy self-management, with two research questions in mind: what are the characteristics of current...

Around the world, about 50 million people suffer from epilepsy, a disease characterized by recurrent and unprovoked seizures of abrupt cerebral activity. Epileptic seizures can present a serious danger to the daily life of patients and the ones surrounding them. Predicting epileptic seizures before they begin, therefore anticipating them, would all...

Biometric identification systems are a fundamental building block of modern security. However, conventional biometric methods cannot easily cope with their intrinsic security liabilities, as they can be affected by environmental factors, can be easily “fooled” by artificial replicas, among other caveats. This has lead researchers to explore other m...

Sleeping or drowsiness while driving contributes to human error, being one of the most relevant causes of traffic collisions and accidents in the world. Although it is foreseen that completely automated vehicles can reduce significantly these numbers, there will be a sequential incorporation of automated vehicles, from existing vehicles, level 0 or...

Studies show that biofeedback increases patient proprioception in physical rehabilitation training, improving outcomes; surface Electromyography (sEMG) is particularly appealing as it enables accurate progress evaluation and instant feedback. Furthermore, extending the rehabilitation processes to patients’ homes has been shown to increase the quali...

People spend more and more time sitting and this habit has been shown to cause spine pathologies. Thus, the scientific community and the industry have become interested in instrumented chairs development to detect incorrect user postures. In this work we present the development and implementation of invisibles and non-intrusive plastic optical fibe...

Over the last years, pervasive wearable technology has spread to people’s daily lives, unobtrusively acquiring large amounts of data. Such devices contain biomedical sensors, prone to contribute for the improvement of the user’s quality of life through artificial intelligence algorithms (e.g. health monitoring and emotion recognition). Physiologica...

eSports is a rapidly growing industry with increasing investment and large-scale international tournaments offering significant prizes. This has led to an increased focus on individual and team performance with factors such as communication, concentration, and team intelligence identified as important to success. Over a similar period of time, pers...

With the beginning of the COVID-19 pandemic in early 2020, there was a pressing need for simple yet effective remote monitoring solutions. In this paper, we describe a low-cost device developed for monitoring COVID-19 patients. The device uses an ESP32 module and integrates two distinct off-the-shelf biomedical sensors: a pulse oximeter by MAXIM, a...

Depression is the leading cause of inability within the active population. The way depression is currently diagnosed is based on the clinician’s subjective examination of patient’s mental status and thus lacks biomarkers to support medical decision. Psychomotor retardation is one of the nine symptoms that are part of DSM-V criteria for major depres...

Non-expensive methods for measuring heart rate and oxygen saturation are of great importance in the scope of the COVID-19 outbreak to follow up on the symptoms and help to control the disease.Smartphones are widely available and their cameras can be used to acquire relevant physiological data, such as Photo-plethysmography (PPG) signals. Covering a...

In this work, a fiber Bragg gratings (FBGs) based sensing insole, capable of simultaneously measure plantar force (PF) and shear force (SF) is proposed. The insole has four measuring points, strategically located for a full gait analysis. Each sensing point contains a sensor-cell which consists in a polylactic acid (PLA) structure, covered by an ep...

There is an increasing interest, in consumer behaviour research related to food and beverage, in taking a step further from the traditional self-report questionnaires and organoleptic properties assessment. With the growing availability of psychophysiological data acquisition devices, and advancements in the study of the underlying signal sources s...

Background and objective: The reliability of low-cost mobile systems for recording Electrocardiographic (ECG) data is mostly unknown, posing questions regarding the quality of the recorded data and the validity of the extracted physiological parameters. The present study compared the BITalino toolkit with an established medical-grade ECG system (B...

Epilepsy is a neurological disease that affects about 50 million people worldwide. It is a disorder of the central nervous system, characterized by recurrent seizures that can have a massive impact in the physical and mental health of the people who suffer from it, as well as their loved ones. Long-term monitoring of epilepsy in uncontrolled enviro...

We present a scoping review of biosensors appropriation as control structures in interactive music systems (IMSs). Technical and artistic dimensions promoted by transdisciplinary approaches, ranging from biomedicine to musical performance and interaction design fields, support a taxonomy for biosensor-driven IMSs. A broad catalog of 70 biosensor-dr...

In 2019, a new virus, SARS-CoV-2, responsible for the COVID-19 disease, was discovered. Asymptomatic and mildly symptomatic patients were forced to quarantine and closely monitor their symptoms and vital signs, most of the time at home. This paper describes e-CoVig, a novel mHealth application, developed as an alternative to the current monitoring...

This paper presents a real-time emotion-annotation tool using a personal mobile device. To this end, an application based on the Valence-Arousal model was developed, following two different approaches (Two-step Sequential Annotation and One-step Matrix Annotation). The application was tested through, an experiment where users performed annotations...

Multiple wearable devices for cardiovascular self-monitoring have been proposed over the years, with growing evidence showing their effectiveness in the detection of pathologies that would otherwise be unnoticed through standard routine exams. In particular, Electrocardiography (ECG) has been an important tool for such purpose. However, wearables h...

A reliable detection of the R-peaks in an electrocar-diogram (ECG) time series is a fundamental step for further heart rate variability (HRV) analysis, biometric recognition techniques and additional ECG waveform based analysis. In this paper, a novel real-time and low-complexity R-peak detection algorithm is presented for single lead ECG signals....

Human-Computer Interaction (HCI) and games set a new domain in understanding people’s motivations in gaming, behavioral implications of game play, game adaptation to player preferences and needs for increased engaging experiences in the context of HCI serious games (HCI-SGs). When the latter relate with people’s health status, they can become a par...

Electrodermal activity (EDA) is a physiological signal that can be measured non-intrusively and associated with the sympathetic nervous system, hence being widely used nowadays. Although multiple sensor designs have been proposed over the years, practical hardware limitations still persist, due to differences in the electrode materials used to inte...

This book constitutes selected papers of the Second International Conference on Computer-Human Interaction Research and Applications, CHIRA 2018, held in Seville, Spain, in September 2018, and Third International Conference on Computer-Human Interaction Research and Applications, CHIRA 2019, held in Vienna, Austria, in September 2019. The 7 full p...

Visual depictions of multiple details related with the anatomy and electrophysiology of the heart, including heartbeat waveforms annotated with the main features. A PDF report is available here: https://www.researchgate.net/publication/346910888_Electrophysiology_of_the_Heart_and_the_Electrocardiogram_Visual_Depictions

Visual depictions of multiple details related with the anatomy and electrophysiology of the heart, including heartbeat waveforms annotated with the main features. Source files are available here: https://www.researchgate.net/publication/346910256_Electrophysiology_of_the_Heart_and_the_Electrocardiogram_Source_Files

The R-peak detection in an Electrocardiography (ECG) signal is of great importance for Heart Rate Variability (HRV) studies and feature extraction based on fiducial points. In this paper, a real-time and low-complexity algorithm for R-peak detection is evaluated on single lead ECG signals. The method is divided in a pre-processing and a detection s...

Currently, mobile devices such as smartphones or tablets are widespread within the student community. However, their potential to be used in classrooms is yet to be fully explored. Our work proposes an approach that benefits from the ease of access to mobile devices, and combines it with state-of-the-art software and hardware. This approach builds...