169,863 research outputs found
Biometric Recognition based on Heart-Induced Chest Vibrations
No full textThe interest in wearable devices has tremendously increased in recent years, thanks the wide range of possible applications in which they can be used. As the employed sensors are able to capture relevant physiological signals, it has been lately proposed to exploit data collected by these instruments for automatic biometric recognition purposes. In this regard, a significant amount of studies has been conducted on the discriminative characteristics of the hearth activity. Within this context, in this paper we investigate the feasibility of recognizing people exploiting measurements of the mechanical vibrations of the chest, induced by the heart activity. To this aim, the effectiveness of combining signals acquired through seismocardiography and gyrocardiography is here evaluated. In order to evaluate the existence of discriminative characteristics within the considered signals, deep learning techniques relying on transfer learning have been applied on the considered measurements. Tests performed on ten subjects have been conducted in order to assess the influence on recognition performance of the positioning on the chest of the employed sensors, as well as the dependence on the posture assumed by the subjects while taking the employed recordings. The obtained results testify that promising recognition rates could be actually achieved when properly placing the considered devices
A novel tool and procedure for in-situ volumetric calibration of motion capture systems for breathing analysis
No full textMedical Smart Textiles Based on Fiber Optic Technology: An Overview
No full textThe growing interest in the development of smart textiles for medical applications is driven by the aim to increase the mobility of patients who need a continuous monitoring of such physiological parameters. At the same time, the use of fiber optic sensors (FOSs) is gaining large acceptance as an alternative to traditional electrical and mechanical sensors for the monitoring of thermal and mechanical parameters. The potential impact of FOSs is related to their good metrological properties, their small size and their flexibility, as well as to their immunity from electromagnetic field. Their main advantage is the possibility to use textile based on fiber optic in a magnetic resonance imaging environment, where standard electronic sensors cannot be employed. This last feature makes FOSs suitable for monitoring biological parameters (e.g., respiratory and heartbeat monitoring) during magnetic resonance procedures. Research interest in combining FOSs and textiles into a single structure to develop wearable sensors is rapidly growing. In this review we provide an overview of the state-of-the-art of textiles, which use FOSs for monitoring of mechanical parameters of physiological interest. In particular we briefly describe the working principle of FOSs employed in this field and their relevant advantages and disadvantages. Also reviewed are their applications for the monitoring of mechanical parameters of physiological interest
Temperature map of kidneys undergoing microwave ablation using computed tomography-thermometry: Ex-vivo experiments and numerical simulations
No full textThis study aims at assessing the temperature distribution in kidney undergoing a two-antennae Microwave Ablation (MWA) at 2.45GHz. The feasibility of thermometry based on Computed Tomography (CT) images were studied, and a 3D finite element model was developed to obtain the organ thermal distribution during the treatment. MWA is a minimally invasive technique used to ablate solid tumors: the tissues electrical properties enable absorption of electromagnetic energy, resulting into heat generation. Hence, the monitoring of tissue temperature during the procedure is pivotal to assure the optimal treatment outcome. CT imaging can be used to monitor the tissue temperature change with a contactless approach and should be calibrated for each organ. The thermal sensitivity of CT thermometry was investigated at two CT scan settings. Four fresh pig kidneys were treated using two MW antennae at 65 W and for 4 minutes, and reference temperature was measured by thermocouples. The relationship between the CT number and the increase of tissue temperature was obtained by using a linear regression analysis, and the thermal sensitivity was estimated as the slope of the best fitting line. The CT number shows an inverse linear relationship with tissue temperature with a thermal sensitivity of approximately -0.34 HU•°C-1. The scan settings have a negligible influence on thermal sensitivity; conversely, at higher kVp and mAs there is a better agreement between the temperature values estimated by CT thermometry and the reference ones. The predictions of the FEM model are confirmed by the measured temperature values, e.g., 80 °C at 1.5 cm from the antennae at the end of the ablation, even though a slight difference exists at bigger distance (33 °C theoretical vs <42 °C experimental). For the deviation of the simplified theoretical model to the real scenario, CT thermometry can be a great benefit: the 2D thermal image can correct the model predictions and has the potential to support the medical doctor in the immediate evaluation of the outcome at clinically relevant locations
Use of wearable systems for the detection of chest-abdominal wall movement aimed at respiratory monitoring in sport: a scoping review on available data
No full textThere is a significant request for wearable systems for vital signs and athletic performance monitoring during sport practice, both in professional and non-professional fields. Respiratory rate is a rather neglected parameter in this field, but several studies show that it is a strong marker of physical exertion. The aim of the present scoping review is to evaluate the number and kind of existing studies on wearable technologies for the analysis of the chest wall movement for respiratory monitoring in sport and fitness. The review included studies investigating the use of contact-based wearable techniques for the detection of chest wall movement for respiratory monitoring during professional or amateur sport, during fitness and physical activity. The search was conducted on PubMed/Medline, Scopus and Google Scholar electronic databases using keywords. Data extracted were entered into a Microsoft Excel spreadsheet by the leading author and then double-checked by the second author. A total of 25 descriptive studies met the inclusion criteria. Few studies on small number of athletes were found, technologies were often evaluated without a reference system, data on participants are sometimes missing. To date, we are not able to draw conclusions on which is the best and most reliable device to use during sport practice
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Design, fabrication and metrological characterization of a 3D-printed strain sensor based on fiber Bragg grating technology
No full textIn the last decades, many smart sensing solutions have been provided for monitoring human health ranging from systems equipped with electrical to mechanical and optical sensors. In this scenario, wearables based on fiber optic sensors like fiber Bragg gratings (FBGs) can be a valuable solution since they show many advantages over the competitors, like miniaturized size, lightness, and high sensitivity. Unfortunately, one of the main issues with this technology is its inherent fragility. For this reason, various encapsulation modalities have been proposed to embed FBG into flexible biocompatible materials for robustness improvements and skin-like appearance. Recently, 3D printing techniques have been proposed to innovate this process thanks to their numerous advantages like a quick fabrication process, high accuracy, repeatability, and resolution. Moreover, the possibility of easily customizing the sensor design by choosing a set of printing parameters (e.g., printing orientation, material selection, shape, size, density, and pattern) can help in developing sensing solutions optimized for specific applications. Here, we present a 3D-printed sensor developed by fused deposition modeling (FDM) with a rectangular shape. A detailed description of the design and fabrication stages is proposed. In addition, changes in the spectral response as well as in the metrological properties of the embedded FBG sensor are investigated. The presented data can be utilized not only for improving and optimizing design and fabrication processes but also may be beneficial for the next research in the production of highly sensitive 3D-printed sensors for applications in wearable technology and, more generally, healthcare setting
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