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1.
Children (Basel) ; 10(10)2023 Oct 05.
Artigo em Inglês | MEDLINE | ID: mdl-37892318

RESUMO

The increasing prevalence of overweight and obesity is a worldwide problem, with several well-known consequences that might start to develop early in life during childhood. The present research based on data from children that have been followed since birth in a previously established cohort study (Generation XXI, Porto, Portugal), taking advantage of State-of-the-Art (SoA) data science techniques and methods, including Neural Architecture Search (NAS), explainable Artificial Intelligence (XAI), and Deep Learning (DL), aimed to explore the hidden value of data, namely on electrocardiogram (ECG) records performed during follow-up visits. The combination of these techniques allowed us to clarify subtle cardiovascular changes already present at 10 years of age, which are evident from ECG analysis and probably induced by the presence of obesity. The proposed novel combination of new methodologies and techniques is discussed, as well as their applicability in other health domains.

2.
Sensors (Basel) ; 23(10)2023 May 11.
Artigo em Inglês | MEDLINE | ID: mdl-37430595

RESUMO

Industrial inspection is crucial for maintaining quality and safety in industrial processes. Deep learning models have recently demonstrated promising results in such tasks. This paper proposes YOLOX-Ray, an efficient new deep learning architecture tailored for industrial inspection. YOLOX-Ray is based on the You Only Look Once (YOLO) object detection algorithms and integrates the SimAM attention mechanism for improved feature extraction in the Feature Pyramid Network (FPN) and Path Aggregation Network (PAN). Moreover, it also employs the Alpha-IoU cost function for enhanced small-scale object detection. YOLOX-Ray's performance was assessed in three case studies: hotspot detection, infrastructure crack detection and corrosion detection. The architecture outperforms all other configurations, achieving mAP50 values of 89%, 99.6% and 87.7%, respectively. For the most challenging metric, mAP50:95, the achieved values were 44.7%, 66.1% and 51.8%, respectively. A comparative analysis demonstrated the importance of combining the SimAM attention mechanism with Alpha-IoU loss function for optimal performance. In conclusion, YOLOX-Ray's ability to detect and to locate multi-scale objects in industrial environments presents new opportunities for effective, efficient and sustainable inspection processes across various industries, revolutionizing the field of industrial inspections.

3.
Sensors (Basel) ; 23(1)2022 Dec 30.
Artigo em Inglês | MEDLINE | ID: mdl-36617000

RESUMO

Soil nutrients assessment has great importance in horticulture. Implementation of an information system for horticulture faces many challenges: (i) great spatial variability within farms (e.g., hilly topography); (ii) different soil properties (e.g., different water holding capacity, different content in sand, sit, clay, and soil organic matter, different pH, and different permeability) for different cultivated plants; (iii) different soil nutrient uptake by different cultivated plants; (iv) small size of monoculture; and (v) great variety of farm components, agroecological zone, and socio-economic factors. Advances in information and communication technologies enable creation of low cost, efficient information systems that would improve resources management and increase productivity and sustainability of horticultural farms. We present an information system based on different sensing capability, Internet of Things, and mobile application for horticultural farms. An overview on different techniques and technologies for soil fertility evaluation is also presented. The results obtained in a botanical garden that simulates the diversity of environment and plant diversity of a horticultural farm are discussed considering the challenges identified in the literature and field research. The study provides a theoretical basis and technical support for the development of technologies that enable horticultural farmers to improve resources management.


Assuntos
Agricultura , Solo , Agricultura/métodos , Fazendas , Jardinagem , Nutrientes , Plantas , Solo/química
4.
Sensors (Basel) ; 21(23)2021 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-34883994

RESUMO

In the field of sensors, in areas such as industrial, clinical, or environment, it is common to find one dimensional (1D) formatted data (e.g., electrocardiogram, temperature, power consumption). A very promising technique for modelling this information is the use of One Dimensional Convolutional Neural Networks (1D CNN), which introduces a new challenge, namely how to define the best architecture for a 1D CNN. This manuscript addresses the concept of One Dimensional Neural Architecture Search (1D NAS), an approach that automates the search for the best combination of Neuronal Networks hyperparameters (model architecture), including both structural and training hyperparameters, for optimising 1D CNNs. This work includes the implementation of search processes for 1D CNN architectures based on five strategies: greedy, random, Bayesian, hyperband, and genetic approaches to perform, collect, and analyse the results obtained by each strategy scenario. For the analysis, we conducted 125 experiments, followed by a thorough evaluation from multiple perspectives, including the best-performing model in terms of accuracy, consistency, variability, total running time, and computational resource consumption. Finally, by presenting the optimised 1D CNN architecture, the results for the manuscript's research question (a real-life clinical case) were provided.


Assuntos
Eletrocardiografia , Redes Neurais de Computação , Teorema de Bayes
5.
J Bodyw Mov Ther ; 25: 53-60, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33714511

RESUMO

BACKGROUND: Stroke is the leading cause of long-term disability in adults, causing residual sensorimotor deficits in many survivors. Patients may have different impairments according to laterality of injury, as well as different responses to some therapies. OBJECTIVE: This preliminary study sought to investigate motor learning in rehabilitation of stroke patients with non-immersive virtual environment by process (electroencephalography) and product (performance) measures in stroke patients with left and right cerebral hemispheres damage. METHODS: The study included 10 chronic stroke patients; 5 with left brain injury (LI), mean age 48.8 years (±4.76), and 5 with right brain injury (RI), mean age 52 years (±10.93). Patients were evaluated for electroencephalographic activity (alpha and beta frequencies) and performance (absolute error) in a darts game on XBOX Kinect (Microsoft®). Then they underwent a virtual darts game training task, 12 sessions for 4 weeks (acquisition stage). After training, they were revaluated (long-term retention). RESULTS: RI group increased alpha power and decreased beta in ipsilesional areas, increased activation on left hemisphere and decreased the absolute error of performance; LI group increased right hemisphere activation and did not decrease the absolute error. CONCLUSIONS: Patients with right brain injury reduce neural effort and errors after virtual darts training, which did not happen to patients with left brain injury. Therefore, the laterality of lesion should be considered in studies that use virtual reality for stroke rehabilitation.


Assuntos
Reabilitação do Acidente Vascular Cerebral , Acidente Vascular Cerebral , Realidade Virtual , Adulto , Eletroencefalografia , Lateralidade Funcional , Humanos , Pessoa de Meia-Idade , Acidente Vascular Cerebral/complicações
6.
Sensors (Basel) ; 20(8)2020 Apr 12.
Artigo em Inglês | MEDLINE | ID: mdl-32290639

RESUMO

Healthcare optimization has become increasingly important in the current era, where numerous challenges are posed by population ageing phenomena and the demand for higher quality of the healthcare services. The implementation of Internet of Things (IoT) in the healthcare ecosystem has been one of the best solutions to address these challenges and therefore to prevent and diagnose possible health impairments in people. The remote monitoring of environmental parameters and how they can cause or mediate any disease, and the monitoring of human daily activities and physiological parameters are among the vast applications of IoT in healthcare, which has brought extensive attention of academia and industry. Assisted and smart tailored environments are possible with the implementation of such technologies that bring personal healthcare to any individual, while living in their preferred environments. In this paper we address several requirements for the development of such environments, namely the deployment of physiological signs monitoring systems, daily activity recognition techniques, as well as indoor air quality monitoring solutions. The machine learning methods that are most used in the literature for activity recognition and body motion analysis are also referred. Furthermore, the importance of physical and cognitive training of the elderly population through the implementation of exergames and immersive environments is also addressed.


Assuntos
Atenção à Saúde , Atividades Cotidianas , Poluição do Ar em Ambientes Fechados , Inteligência Artificial , Nível de Saúde , Humanos , Internet das Coisas , Monitorização Fisiológica/métodos , Tecnologia sem Fio
7.
Sensors (Basel) ; 19(24)2019 Dec 13.
Artigo em Inglês | MEDLINE | ID: mdl-31847210

RESUMO

The present work tries to fill part of the gap regarding the pilots' emotions and their bio-reactions during some flight procedures such as, takeoff, climbing, cruising, descent, initial approach, final approach and landing. A sensing architecture and a set of experiments were developed, associating it to several simulated flights ( N f l i g h t s = 13 ) using the Microsoft Flight Simulator Steam Edition (FSX-SE). The approach was carried out with eight beginner users on the flight simulator ( N p i l o t s = 8 ). It is shown that it is possible to recognize emotions from different pilots in flight, combining their present and previous emotions. The cardiac system based on Heart Rate (HR), Galvanic Skin Response (GSR) and Electroencephalography (EEG), were used to extract emotions, as well as the intensities of emotions detected from the pilot face. We also considered five main emotions: happy, sad, angry, surprise and scared. The emotion recognition is based on Artificial Neural Networks and Deep Learning techniques. The Root Mean Squared Error (RMSE) and Mean Absolute Error (MAE) were the main methods used to measure the quality of the regression output models. The tests of the produced output models showed that the lowest recognition errors were reached when all data were considered or when the GSR datasets were omitted from the model training. It also showed that the emotion surprised was the easiest to recognize, having a mean RMSE of 0.13 and mean MAE of 0.01; while the emotion sad was the hardest to recognize, having a mean RMSE of 0.82 and mean MAE of 0.08. When we considered only the higher emotion intensities by time, the most matches accuracies were between 55% and 100%.


Assuntos
Emoções/fisiologia , Expressão Facial , Adulto , Eletroencefalografia , Feminino , Resposta Galvânica da Pele/fisiologia , Frequência Cardíaca/fisiologia , Humanos , Masculino , Adulto Jovem
8.
Behav Sci (Basel) ; 10(1)2019 Dec 19.
Artigo em Inglês | MEDLINE | ID: mdl-31861632

RESUMO

BACKGROUND: The present study's main aim was to determine the predictors of movie rewatchability and recommendations. METHODS: Using a sample of 318 participants, we first tested the structure of a gratification scale from watching a movie. Then, we examined the role of age, need for cognition, need for affect, extraversion, and emotional gratifications, in predicting individuals' interest in rewatching the movie and in making recommendations. RESULTS: As in the original proposal of the emotional gratification scale, the following dimensions were identified: fun, thrill, empathic sadness, release of emotions, social sharing, contemplative experiences, and character engagement, with acceptable model fit and reliability, convergent and divergent validity. Social sharing, contemplate experiences, need for affect and age were significant predictors of movie recommendation; whereas social sharing, thrill, extraversion, and age contributed most to explaining rewatching interest. CONCLUSION: This study highlights the importance of considering distinct gratifications and individual differences in predicting rewatching and movie recommendation.

9.
Ciênc. Saúde Colet. (Impr.) ; 24(12): 4727-4738, dez. 2019. tab, graf
Artigo em Inglês | LILACS | ID: biblio-1055734

RESUMO

Abstract Several anti-smoking campaigns have been used for decades to reduce smoking consumption. However, so far, there is no consensus regarding the effectiveness of inducing distinct emotions in reducing smoke consumption. This study tested the effects of two types of anti-smoking ads, inducing fear or humor, on emotions, perceived effectiveness, support for tobacco control policies, urges to smoke, and susceptibility to smoke. Participants (N = 108; 54 smokers) of both genders were randomly assigned to one of the two following emotion ads condition: fear (N = 52) or humor (N = 56). During exposure, the continuous flow of their emotions by self-report and physiologically was collected. Measures of ads impact on emotions, perceived effectiveness, urges and susceptibility to smoking, and support for tobacco policies were applied after exposure. The results have shown that fear ads were perceived as more effective and reduced the urges to smoke in smokers. Non-smokers were more supportive of tobacco control policies. In conclusion, this study showed that fear campaigns can reduce the urge to smoke among smokers and are perceived to be more effective. This perceived effectiveness can be partially explained by feelings of fear, regardless the other emotions it also triggers, and of the smoking status.


Resumo Várias campanhas antitabágicas são usadas para reduzir o consumo de tabaco. No entanto, até ao momento não existe um consenso sobre a eficácia da indução de emoções específicas nestas campanhas. Este estudo testou os efeitos de dois tipos de campanhas antitabágicas, induzindo Medo ou Humor, nas emoções, na perceção de eficácia das campanhas, no apoio a políticas antitabágicas, no desejo de fumar, e na suscetibilidade para fumar. Os participantes (N = 108; 54 fumadores), de ambos os sexos, foram aleatoriamente distribuídos para uma das seguintes campanhas indutoras de emoções: medo (N = 52) ou humor (N = 56). Durante a exposição, registou-se o fluxo contínuo das emoções autorreportadas e as respostas fisiológicas. Após a exposição avaliou-se o impacto das campanhas nas emoções, na perceção de eficácia, nas políticas antitabágicas, no desejo e na suscetibilidade para fumar. Os resultados evidenciaram que as campanhas indutoras de medo foram percecionadas como mais eficazes e reduziram o desejo de fumar em fumadores. Políticas antitabágicas foram mais apoiadas por não fumadores. Futuramente deverá considerar-se que induzir diferentes emoções em campanhas antitabágicas pode ter efeitos distintos a nível afetivo e cognitivo, com possível relevância para a mudança comportamental.


Assuntos
Humanos , Masculino , Feminino , Adolescente , Adulto , Adulto Jovem , Senso de Humor e Humor como Assunto/psicologia , Publicidade/métodos , Medo/psicologia , Prevenção do Hábito de Fumar/métodos , Fumantes/psicologia , Política Pública , Emoções , não Fumantes/psicologia , Pessoa de Meia-Idade
10.
Cien Saude Colet ; 24(12): 4727-4738, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31778522

RESUMO

Several anti-smoking campaigns have been used for decades to reduce smoking consumption. However, so far, there is no consensus regarding the effectiveness of inducing distinct emotions in reducing smoke consumption. This study tested the effects of two types of anti-smoking ads, inducing fear or humor, on emotions, perceived effectiveness, support for tobacco control policies, urges to smoke, and susceptibility to smoke. Participants (N = 108; 54 smokers) of both genders were randomly assigned to one of the two following emotion ads condition: fear (N = 52) or humor (N = 56). During exposure, the continuous flow of their emotions by self-report and physiologically was collected. Measures of ads impact on emotions, perceived effectiveness, urges and susceptibility to smoking, and support for tobacco policies were applied after exposure. The results have shown that fear ads were perceived as more effective and reduced the urges to smoke in smokers. Non-smokers were more supportive of tobacco control policies. In conclusion, this study showed that fear campaigns can reduce the urge to smoke among smokers and are perceived to be more effective. This perceived effectiveness can be partially explained by feelings of fear, regardless the other emotions it also triggers, and of the smoking status.


Assuntos
Publicidade/métodos , Medo/psicologia , Fumantes/psicologia , Prevenção do Hábito de Fumar/métodos , Senso de Humor e Humor como Assunto/psicologia , Adolescente , Adulto , Emoções , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , não Fumantes/psicologia , Política Pública , Adulto Jovem
11.
Sensors (Basel) ; 19(17)2019 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-31480331

RESUMO

Ataxias are a group of neurodegenerative disorders characterized by cerebellar dysfunction that cause irregularities in the rate, rhythm, amplitude, and force of voluntary movements. The electrooculogram (EOG) may provide clues about ataxic disorders because most of these patients have difficulty with visual tracking and fixing their gaze. Using electrodes, EOG records the biopotentials generated by eye movements. In this paper, three surface electrodes are placed around the eye socket, and the biopotentials generated by eye movements are acquired using a commercial bioamplifier device. Next, the signals are sent to the computer to be digitally processed to extract the rate of saccades as well as the delay and deviation of the gaze in response to a stimulus. These features are analysed in a novel software application designed to help physicians in evaluating ataxia. After applying several tests to both healthy and ataxia-affected patients, differences in EOG results were found. The evaluation of the reliability of the designed software application is made according to three metrics: sensitivity, specificity, and accuracy. The results indicate the proposed system's viability as an affordable method for evaluation of ataxic disorders.


Assuntos
Ataxia/diagnóstico , Eletroculografia/métodos , Idoso , Computadores , Eletroculografia/instrumentação , Movimentos Oculares , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estimulação Luminosa , Reprodutibilidade dos Testes , Movimentos Sacádicos , Processamento de Sinais Assistido por Computador , Software , Interface Usuário-Computador
12.
Sensors (Basel) ; 18(2)2018 Feb 10.
Artigo em Inglês | MEDLINE | ID: mdl-29439428

RESUMO

This paper presents a measurement system intended to monitor the usage of walker assistive devices. The goal is to guide the user in the correct use of the device in order to prevent risky situations and maximize comfort. Two risk indicators are defined: one related to force unbalance and the other related to motor incoordination. Force unbalance is measured by load cells attached to the walker legs, while motor incoordination is estimated by synchronizing force measurements with distance data provided by an optical sensor. The measurement system is equipped with a Bluetooth link that enables local supervision on a computer or tablet. Calibration and experimental results are included in the paper.

13.
Sensors (Basel) ; 17(7)2017 Jun 26.
Artigo em Inglês | MEDLINE | ID: mdl-28672863

RESUMO

The development of a novel computer writing system based on eye movements is introduced herein. A system of these characteristics requires the consideration of three subsystems: (1) A hardware device for the acquisition and transmission of the signals generated by eye movement to the computer; (2) A software application that allows, among other functions, data processing in order to minimize noise and classify signals; and (3) A graphical interface that allows the user to write text easily on the computer screen using eye movements only. This work analyzes these three subsystems and proposes innovative and low cost solutions for each one of them. This computer writing system was tested with 20 users and its efficiency was compared to a traditional virtual keyboard. The results have shown an important reduction in the time spent on writing, which can be very useful, especially for people with severe motor disorders.

14.
J Biomed Opt ; 22(9): 91507, 2017 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-28243676

RESUMO

In an era of unprecedented progress in technology and increase in population age, continuous and close monitoring of elder citizens and patients is becoming more of a necessity than a luxury. Contributing toward this field and enhancing the life quality of elder citizens and patients with disabilities, this work presents the design and implementation of a noninvasive platform and insole fiber Bragg grating sensors network to monitor the vertical ground reaction forces distribution induced in the foot plantar surface during gait and body center of mass displacements. The acquired measurements are a reliable indication of the accuracy and consistency of the proposed solution in monitoring and mapping the vertical forces active on the foot plantar sole, with a sensitivity up to 11.06 ?? pm / N . The acquired measurements can be used to infer the foot structure and health condition, in addition to anomalies related to spine function and other pathologies (e.g., related to diabetes); also its application in rehabilitation robotics field can dramatically reduce the computational burden of exoskeletons' control strategy. The proposed technology has the advantages of optical fiber sensing (robustness, noninvasiveness, accuracy, and electromagnetic insensitivity) to surpass all drawbacks verified in traditionally used sensing systems (fragility, instability, and inconsistent feedback).


Assuntos
Pé/fisiologia , Marcha , Monitorização Fisiológica/instrumentação , Monitorização Fisiológica/métodos , Fibras Ópticas , Pressão , Fenômenos Biomecânicos , Humanos
15.
Annu Int Conf IEEE Eng Med Biol Soc ; 2015: 442-5, 2015 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-26736294

RESUMO

In the last decade researches on laterality of brain functions have been reinvigorated. New models of lateralization of brain functions were proposed and new methods for understanding mechanisms of asymmetry between right and left brain functions were described. We design a system to study laterality of motor and autonomic nervous system based on wearable sensors network. A mobile application was developed for analysis of upper and lower limbs movements, cardiac and respiratory function. The functionalities and experience gained with deployment of the system are described.


Assuntos
Encéfalo , Lateralidade Funcional , Movimento
16.
Artigo em Inglês | MEDLINE | ID: mdl-24111361

RESUMO

In this paper we describe and compared method of heart rate estimation from cardiac signal acquired with EMFIT, FMCW Doppler radar and Finapres based technology, in the same context, and briefly investigated their similarities and differences. Study of processing of acquired cardiac signal for accurate peak detection using Wavelet Transform is also described. The results suggest good reliability of the two implemented unobtrusive systems for heart rate estimation.


Assuntos
Balistocardiografia , Efeito Doppler , Frequência Cardíaca , Coração/fisiologia , Radar , Processamento de Sinais Assistido por Computador , Adulto , Eletrocardiografia , Humanos , Pessoa de Meia-Idade , Reprodutibilidade dos Testes , Análise de Ondaletas
17.
Artigo em Inglês | MEDLINE | ID: mdl-22254706

RESUMO

Unobtrusive monitoring of the cardio-respiratory and daily activity for wheelchair users became nowadays an important challenge, considering population aging phenomena and the increasing of the elderly with chronic diseases that affect their motion capabilities. This work reports the utilization of FMCW (frequency modulated continuous wave) Doppler radar sensors embedded in a manual wheelchair to measure the cardiac and respiratory activities and the physical activity of the wheelchair user. Another radar sensor is included in the system in order to quantify the motor activity through the wheelchair traveled distance, when the user performs the manual operation of the wheelchair. A conditioning circuit including active filters and a microcontroller based primary processing module was designed and implemented to deliver the information through Bluetooth communication protocol to an Android OS tablet computer. The main capabilities of the software developed using Android SDK and Java were the signal processing of Doppler radar measurement channel signals, graphical user interface, data storage and Wi-Fi data synchronization with remote physiological and physical activity database.


Assuntos
Actigrafia/instrumentação , Diagnóstico por Computador/instrumentação , Eletrocardiografia/instrumentação , Monitorização Ambulatorial/instrumentação , Radar/instrumentação , Taxa Respiratória , Cadeiras de Rodas , Desenho de Equipamento , Análise de Falha de Equipamento , Reprodutibilidade dos Testes , Sensibilidade e Especificidade
18.
Artigo em Inglês | MEDLINE | ID: mdl-22254896

RESUMO

In this paper Heart Rate Variability (HRV) and Blood Pressure Variability (BPV) were analyzed before the onset of cardiac arrhythmia in order to derive markers for short-term forecasting. The (a) coherence between systolic blood pressure (SBP) and cardiac oscillations in low-frequency (LF) and high-frequency (HF) band; (b) fluctuations of phase; (c) HRV and BPV as a LF power and HF power in frequency and time-frequency domain; (d) transfer function analysis of cardiovascular signals were analyzed. Arrhythmia was preceded by: a) lower coherence; b) increase in fluctuations of phase between signals; c) higher spectral energy associated with respiratory frequency in blood pressure signal; d) raise of sympathetic outflow to the heart; e) decreased HRV. Cardiac arrhythmia was characterized mainly by an increase in LF power of blood pressure, cardiac signal and transfer function. During self-termination of arrhythmia a larger increased in total BPV and HRV was recorded. These results suggest that important information about both neuronal cardiovascular control and risk for spontaneous arrhythmia can be provided by combined analysis of frequency, phase, and time-frequency analysis of blood pressure and cardiac oscillation.


Assuntos
Pressão Sanguínea , Frequência Cardíaca , Algoritmos , Fibrilação Atrial/fisiopatologia , Humanos
19.
Artigo em Inglês | MEDLINE | ID: mdl-21096105

RESUMO

Biomedical signals are customarily overlaid with interferences and noise, furthermore, baseline wandering is another significant drawback to their accurate interpretation, especially if the implementation platform is a wheelchair. The nonlinear processes which generate the physiologic signals, and the disturbances, regularly exclude, or limit, the usage of classical linear techniques, hence, among other options, wavelets have been used to decompose the signals. Unobtrusively acquired signals are prone to have important baseline fluctuations, namely contactless impedance plethysmogram, and ballistocardiogram, therefore making them apposite to detrending. Sensing hardware was embedded in a wheelchair to acquire these signals, given the valuable information provided about the cardiovascular system of the monitored subject. This work also reports the improvements achieved by automatic wavelet detrending application in the real-time processing of these signals. Although significant baseline wavering is acquired, important enhancements are swiftly computed without noteworthy error.


Assuntos
Artefatos , Diagnóstico por Computador/métodos , Eletrocardiografia Ambulatorial/métodos , Fotopletismografia/métodos , Análise de Ondaletas , Cadeiras de Rodas , Algoritmos , Feminino , Humanos , Masculino , Reprodutibilidade dos Testes , Sensibilidade e Especificidade
20.
Artigo em Inglês | MEDLINE | ID: mdl-21096778

RESUMO

When recording the pressure oscillations of a seated subject two distinct effects are assessed, ample vibrations due to the person's movement, and periodic oscillations of small amplitude due to cardiopulmonary activity, expressed by the ballistocardiogram (BCG). Embedding a pressure sensor in a chair's back or seat allows unobtrusive monitoring of the BCG. However, inconspicuously acquired signals are affected by numerous artifacts, often generated by the subject's forgetfulness, and posture changes due to lack of constrains. Moreover, the signal changes considerably its shape from person to person, and when the seating posture, or conversely, sensor position, is different. For real-time continuous monitoring, it is still to be found a method which, without introducing significant delays, can deal with such volatility. Thus, tailored calibration of peak detectors and other algorithms is recurrent, and even so, the neighboring samples of artifacts are possibly untreatable. This work evaluates the advantages of Empirical Mode Decomposition, as well as a coarser demodulation approach of the BCG signal, as dependable methods to allow real-time heart rate estimation on unstable BCG records. An analysis of the Fourier transform of the demodulated signals is the method used to provide and compare robustness of heart rate estimates.


Assuntos
Algoritmos , Arritmias Cardíacas/diagnóstico , Arritmias Cardíacas/fisiopatologia , Artefatos , Balistocardiografia/métodos , Diagnóstico por Computador/métodos , Frequência Cardíaca , Adulto , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Cadeiras de Rodas
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