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This paper works on detecting a person in bed for sleep routine and sleep pattern monitoring based on the Micro-Electro-Mechanical Systems (MEMS) accelerometer and Internet of Things (IoT) embedded system board. This work provides sleep information, patient assessment, and elderly care for patients who live alone via tele-distance to doctors or family members. About 216,000 pieces of acceleration data were collected, including three classes: no person in bed, a static laying position, and a moving state for Artificial Intelligence (AI) application. Six well-known Machine-Learning (ML) algorithms were evaluated with precision, recall, F1-score, and accuracy in the workstation before implementing in the STM32-microcontroller for real-time state classification. The four best algorithms were selected to be programmed into the IoT board and applied for real-time testing. The results demonstrate the high accuracy of the ML performance, more than 99%, and the Classification and Regression Tree algorithm is among the best models with a light code size of 1583 bytes. The smart bed information is sent to the IoT dashboard of Node-RED via a Message Queuing Telemetry broker (MQTT). [ABSTRACT FROM AUTHOR]

The lack of physical exercise is among the most relevant factors in developing health issues, and strategies to incentivize active lifestyles are key to preventing these issues. The PLEINAIR project developed a framework for creating outdoor park equipment, exploiting the IoT paradigm to build "Outdoor Smart Objects" (OSO) for making physical activity more appealing and rewarding to a broad range of users, regardless of their age and fitness. This paper presents the design and implementation of a prominent demonstrator of the OSO concept, consisting of a smart, sensitive flooring, based on anti-trauma floors commonly found in kids playgrounds. The floor is equipped with pressure sensors (piezoresistors) and visual feedback (LED-strips), to offer an enhanced, interactive and personalized user experience. OSOs exploit distributed intelligence and are connected to the Cloud infrastructure by using a MQTT protocol; apps have then been developed for interacting with the PLEINAIR system. Although simple in its general concept, several challenges must be faced, related to the application range (which called for high pressure sensitivity) and the scalability of the approach (requiring to implement a hierarchical system architecture). Some prototypes were fabricated and tested in a public environment, providing positive feedback to both the technical design and the concept validation. [ABSTRACT FROM AUTHOR]

This paper aims at exploring and validating the adoption of standard fabrication processes for the realization of CMOS active pixel sensors, for particle detection purposes. The goal is to implement a single-chip, complete radiation sensor system, including on a CMOS integrated circuit the sensitive devices, read-out and signal processing circuits. A prototype chip (RAPS01) based on these principles has been already fabricated, and a chip characterization has been carried out; in particular, the evaluation of the sensitivity of the sensor response on the actual operating conditions was estimated, as well as the response uniformity. Optimization and tailoring of the sensor structures for High Energy Physics applications are being evaluated in the design of the next generation chip (RAPS02). Basic features of the new chip includes digitally configurable readout and multi-mode access (i.e., either sparse of line-scan readout).

In this paper, we discuss some issues related to the design, implementation, and test of a CMOS active pixel sensor chip (RAPS01), developed in the framework of the radiation active pixel sensors (RAPS) INFN project. Two different basic pixel schemes have been proposed. The first one is based on a standard active pixel sensor (APS) architecture, while a second architecture, named weak inversion pixel sensor (WIPS) exploits a different circuitry which allows for 'sparse' access mode and thus for speeding-up the readout phase. Chip fabrication has been completed and a preliminary test phase has been performed. A suitable test environment has been devised and test strategies have been planned. Preliminary test results, featuring a static and dynamic characterization of the basic sensitive elements are outlined. Future works are also outlined, aimed at the optimization of a second version of the chip, more effectively integrating smart circuitry. Index Terms--Active pixel, CMOS, radiation sensor.

In this paper, a simulator based on a global electromagnetic model is presented, suited for the analysis of HF integrated and hybrid electronic circuits. The model is based on the self-consistent solution of Maxwell's equation and of semiconductor transport equations, exploiting a generalized finite-difference time-domain (FDTD) scheme. The tool is, therefore, capable of accounting, on a distributed basis, for actual interactions between wave propagation and charge transport, and is capable of providing a physically based picture of traveling-wave semiconductor devices. The implementation is such that more conventional algorithms (e.g., lumped-element FDTD or plain FDTD) can be regarded as a subset of the global scheme itself. This makes it possible to intermix different physical models, featuring different degrees of physical accuracy and computational efficiency, within the same simulation environment. Main features of such an environment are described by means of the simulation of a simple 76-GHz distributed switch.

A new simulation method has been devised using a three-dimensional finite-difference time-domain scheme and numerical device simulation to model solid-state devices and their full-wave, electromagnetic interconnections. The method, which uses finite-difference time-domain discretization, is precise and reliable for mixed-mode simulation. It is applicable for a number of applications.

Mathematical analysis using ion-sensitive and photo-sensitive transduction mechanisms has been applied to assess charge transport in light-addressable potentiometric sensors. The general purpose device simulator has been modified to accommodate electrolyte ion layers and luminous stimulus processes. The resulting LAPS technique is reliable and accurate to use.

A three-dimensional (3-D) implementation of the lumped-element finite-difference time-domain (FDTD) algorithm has been carried out. To accomplish proper description of device dynamic responses, the code incorporates accurate models of lumped bipolar devices, including nonlinear capacitances associated with pn and Schottky junctions. The nonlinear system arising from discretized lumped-element equations is solved by means of an iterative Newton-Raphson algorithm, the convergence properties of which are sensitive to the value of the simulation time step. The computational efficiency of the algorithm (as well as its robustness) has significantly been enhanced by introducing an adaptive time-step algorithm, which dynamically adjusts the time-step itself to ensure convergence during the simulation. Several simulation examples are compared with conventional analysis techniques and demonstrate the algorithm reliability as well as its increased efficiency.

This article presents an automated procedure for acquisition and analysis of BallistoCardioGraphy (BCG) traces. A triaxial accelerometer and a microcontroller unit are used to record heart-induced recoil forces generated from a lying subject. The problem of BCG J-peak annotation is split into two subtasks: candidates extraction, based on a detection signal, and actual annotation, guided by subject-specific search windows. Such a procedure is derived from an automatic calibration, which is carried out with no need of concurrent ElectroCardioGram (ECG) or user intervention. The algorithm also implements postannotation checks for refinement of annotation, which effectively reduces the number of missed J-peaks. The impact of each algorithm phase is analyzed, assessing statistical significance of each step; finally, performance is optimized in a data-driven fashion. Results show that the proposed methodology is able to achieve high sensitivity and precision (the median score is 98.9% and 98.1%, respectively) in J-peak detection. The quality of J-peaks timing annotation is further demonstrated by a very low discrepancy between BCG and ECG heart rate (HR) estimates. Overall population, the standard deviation of such error was found to be approximately 6.56 ms, whereas the mean absolute error was just 4.7 ms (i.e., ≈ 1.18; Ts, where Ts = 4 ms is the sampling period). Such scores, indeed, improve over recent related literature. [ABSTRACT FROM AUTHOR]

This article presents an unsupervised, automated procedure for the analysis of Seismocardiogram (SCG) signals. SCG is a measure of chest vibrations, induced by the mechanical activity of the heart, which allows extracting relevant parameters, including heart rate (HR) and HR variability (HRV). An initial self-calibration is performed, solely based on the SCG traces, yielding a suitable heartbeat template (personalized for each subject). Then, beat detection and timing annotation are performed in two steps: at first, candidate beats are identified and validated, by means of suitably defined detection signals; then, precise timing annotation is achieved by best aligning such candidate beats to the previously extracted template. The algorithm has been validated on two separate data sets, featuring different acquisition setups: the first one is the publicly available Combined measurement of ECG, Breathing and Seismocardiogram (CEBS) database, reporting SCG signals from the subjects lying in supine position, whereas the second one was acquired using a custom setup, involving the sitting subjects. Results show good sensitivity and precision scores (98.5% and 98.6% for the CEBS database, and 99.1% and 97.9% for the Custom one, respectively). In addition, comparison with electrocardiogram (ECG) gold-standard is given, showing good agreement between the beat-to-beat intervals computed from SCG and the ECG gold-standard: on average, R2 scores of 99.3% and 98.4% are achieved on the CEBS and Custom data sets, respectively. Furthermore, a low rms error is achieved on the CEBS and Custom data sets, amounting to 4.6 and 6.2 ms, respectively (i.e., 2.3 Ts and 3.1 Ts, where Ts is the sampling period): such results are well compared with related literature. Validation on two different data sets indicates the robustness of the proposed methodology. [ABSTRACT FROM AUTHOR]

This paper presents a fully automated procedure for acquiring and analyzing seismocardiographic (SCG) traces from an inertial measurement unit (IMU) placed over a subject’s sternum. An automated calibration procedure allows for straightforward adaption to different subjects. Calibration is performed once per subject, exploiting electrocardiogram (ECG) markers; relevant patterns and parameters are automatically extracted and used for successive SCG processing, which does not require concurrent ECG information any longer. Annotation of SCG traces is performed in two steps: in the first one, a suitably engineered signal is derived from SCG and used as coarse heartbeat detector; then, the annotation can be performed by comparing the prototype extracted at calibration time with segments of SCG data, near to the detected beats. The proposed methodology is validated by direct comparison with ECG, adopted as gold standard. In particular, three main metrics are taken into account: sensitivity (i.e., the percentage of correctly identified heartbeats, compared to ECG), precision (i.e., impact of false positives on truly detected beats), and $ {R^{2}}$ (i.e., linearity between beat-to-beat measurements as computed by ECG and SCG). Results show satisfactory performance, more than adequate to continuous, long-term monitoring: overall, approximately 90% of heartbeats are correctly detected, on average, with minimal false positives (${\approx 1}$ %). Linearity between ECG- and SCG-computed beat-to-beat intervals is extremely high ($ {R^{2}>0.95}$ , on average), indicating good agreement between the two measurement methods. These results suggest that SCG can be used as a reliable, contactless measure of heart-related parameters. [ABSTRACT FROM AUTHOR]

Location-based services have increased in popularity in recent years and can be fruitfully exploited in the field of smart homes, opening the doors to a wide range of personalized services. In this context, radio technology can be widely employed since, other than connecting devices in the home system, it offers solutions for the user localization issue without the need of any extra device. Techniques based on received signal strength indicator (RSSI) are often used, relying on fingerprinting or proximity algorithms. In this paper, a novel RSSI-based fingerprinting approach for room-level localization is presented: it is a threshold algorithm based on receiver operating characteristic analysis. Moreover, the actual user location is estimated from his/her interaction with the home system devices deployed in the house: if the home environment is inhabited by more than one person, it becomes of utmost importance the identification of who is actually interacting with a given device. A proximity method is exploited for this purpose. Tests have been carried out to characterize the approach, particularly, the effects of RSSI samples, number and position, of the anchor nodes have been analyzed. Finally, some considerations about power consumption of the mobile node have been presented. [ABSTRACT FROM AUTHOR]

The adoption of overhanging-metal contacts has been suggested as an effective means to limit breakdown risks in heavy-damaged high-voltage biased microstrip detectors. In this paper, the influence of the overhang on device noise parameters is analyzed, with particular reference to the interstrip capacitance. Data have been collected on a set of detectors featuring variable overhang extensions and different width/pitch ratios, and numerical simulation has been exploited to provide physical interpretation of the experimental findings. In particular, the nontrivial dependence of interstrip capacitance over geometrical parameters is discussed. By looking at leakage currents and charge collection as well, it is shown that limited-extension overhangs still have highly beneficial effects on the breakdown properties while having no practical drawbacks on the detector performance. Index Terms--Microstrip, radiation detectors, simulation.

Among sensible goals of active and assisted living paradigm is the unobtrusive monitoring of daily living activities. Based on such monitoring, anomalies and trends can be discovered, which possibly allows for early assessment of health issues and for prevention policies. However, when dealing with the home environment, and especially with older adults, obtrusiveness, usability, and cost concerns are of the utmost relevance. Smart objects can be designed to this purpose and deployed into the home: they usually feature low data rates and are customarily implemented by relying on conventional wireless sensor network approaches (ZigBee, Z-Wave, etc). This, however, results in “ad hoc” home networking, which is somehow obtrusive, complicated, and possibly expensive. In this paper, we discuss the implementation of behavioral sensors based on the familiar and ubiquitous Wi-Fi technology, suitable for a “plug-and-play” deployment. Sensors are connected to a cloud platform, embodying a genuine Internet of Things approach. With respect to conventional approaches, much better scalability, flexibility, and inexpensiveness can be attained. The main expected drawback comes from the higher power consumption, inherently needed to sustain much higher data rates. This paper focuses on such an issue, illustrating design techniques aimed at optimizing power consumption and battery lifetime. Performance results are shown, which definitely fall within a practical range and are fully comparable with more conventional approaches. [ABSTRACT FROM PUBLISHER]

Food intake and eating habits have a significant impact on people’s health. Widespread diseases, such as diabetes and obesity, are directly related to eating habits. Therefore, monitoring diet can be a substantial base for developing methods and services to promote healthy lifestyle and improve personal and national health economy. Studies have demonstrated that manual reporting of food intake is inaccurate and often impractical. Thus, several methods have been proposed to automate the process. This article reviews the most relevant and recent researches on automatic diet monitoring, discussing their strengths and weaknesses. In particular, the article reviews two approaches to this problem, accounting for most of the work in the area. The first approach is based on image analysis and aims at extracting information about food content automatically from food images. The second one relies on wearable sensors and has the detection of eating behaviours as its main goal. [ABSTRACT FROM PUBLISHER]

A balanced diet is the key to a healthy lifestyle and is crucial for preventing or dealing with many chronic diseases such as diabetes and obesity. Therefore, monitoring diet can be an effective way of improving people's health. However, manual reporting of food intake has been shown to be inaccurate and often impractical. This paper presents a new approach to food intake quantity estimation using image-based modeling. The modeling method consists of three steps: firstly, a short video of the food is taken by the user's smartphone. From such a video, six frames are selected based on the pictures' viewpoints as determined by the smartphone's orientation sensors. Secondly, the user marks one of the frames to seed an interactive segmentation algorithm. Segmentation is based on a Gaussian Mixture Model alongside the graph-cut algorithm. Finally, a customized image-based modeling algorithm generates a point-cloud to model the food. At the same time, a stochastic object-detection method locates a checkerboard used as size/ground reference. The modeling algorithm is optimized such that the use of six input images still results in an acceptable computation cost. In our evaluation procedure, we achieved an average accuracy of 92% on a test set that includes images of different kinds of pasta and bread, with an average processing time of about 23 s. [ABSTRACT FROM AUTHOR]

Behavioral analysis, based on unobtrusive monitoring through environmental sensors, is expected to increase health awareness of AAL systems. In this paper, techniques for assessing behavioral quantitative features are discussed, suitable for detecting behavioral anomalies in an unsupervised fashion, i.e., with no need of defining target reference behaviors and of tuning user-specific threshold parameters. Such technique is being exploited for analyzing data coming from a set of European pilot sites, in the framework of the EU/AAL-JP project "FOOD", specifically focused at kitchen activity. Simple results are illustrated, suitable for proof-of-concept validation. [ABSTRACT FROM AUTHOR]

As the average age of the EU population increases, ICT solutions are going to play a key role in order to find answers to the new challenges the demographic change is carrying on. At the University of Parma an AAL (Ambient Assisted Living) system named CARDEA has been developed during the last 10 years. Within CARDEA, behavioral analysis is carried out, based on environmental sensors. If multiple users live in the same environment, however, data coming from sensors need to be properly tagged: in this paper, a simple technique for such tagging is proposed, which exploits the same wireless transmission used for transmitting data, thus not requiring additional hardware components and avoiding more complex and expensive (radio)localization techniques. Preliminary results are shown, featuring a satisfactory accuracy. [ABSTRACT FROM AUTHOR]

We present a complete BCI-enabled (Brain Computer Interface) solution for Ambient Assisted Living system control. BCI are alternative, augmentative communication means capable of exploiting just the brain waveforms to infer intent, thus potentially posing as a technological bridge capable of overcoming limitations in the usual neuromuscular pathways. The module was completely developed in a customized way, encompassing hardware and software components. We demonstrate the effectiveness of the approach on a practical control scenario in which the user can issue 4 different commands, at his own pace and will, in real-time. No initial calibration is necessary, in line with the aimed plug&play approach. Results are very promising, especially in false positives rejection, well improving over literature. [ABSTRACT FROM AUTHOR]

In this paper, the issue of numerical modeling of radiation-damaged silicon devices is discussed, with reference to radiation detectors employed in high-energy physics experiments. Since the actual physical picture is far too complex to be accounted for at a first-principle (i.e., defect kinetics) level and not yet fully understood, a hierarchical approach has been followed looking for a suitable approximation of macroscopic changes of the electrical behavior of silicon device induced by radiation damage. In particular, a three deep-level trapping mechanism is accounted for by means of Shockley-Read-Hall theory, whereas shallow-level sensitivity on the radiation is considered by means of a donor-removal model. Index Terms--Radiation damage, silicon detectors.

Recently, radio frequency identification (RFID) systems have gained popularity in manufacturing units, inventory, and logistics, as they represent an inexpensive and reliable solution for automatic identification. Moreover, RFID transponders are expected to become a key element in the ubiquitous computing scenario. Tags will likely be used to collect sensors data, enabling noninvasive environment monitoring. Low-cost passive UHF transponders are expected to play a major role in this context, due to extended read range capabilities. Within a passive tag, power harvested from the field irradiated by the reader during the communication should operate both digital control circuitry and potential sensing devices. Exploiting ultra-low power tag circuitry would provide sensing sections with higher energy, thus improving measurement performance. In this paper, the design of a novel circuit is presented, which implements the baseband processor of a UHF-RFID tag in compliance with the ISO 18000-6B protocol. Regardless of protocol selection issues, several power saving strategies are devised, both at the system and circuit levels, suitable for passive transponder implementation. Near-threshold operation has been exploited to attain ultra-low power consumption while keeping fair performance. A set of standard cells has been designed, suitable for the power-limited specific application. The proposed solution has been successfully checked by means of a physical implementation on CMOS 0.18 μm technology. Test chips have been characterized in terms of voltage and frequency operating range and power consumption figure has been extensively analyzed. Measurement results fully support the selected design approach: the baseband processor dissipates only 440 nW average power when operated at 800 kHz and 0.6 V. This extremely-low power consumption enables high-performance ubiquitous computing. [ABSTRACT FROM AUTHOR]

Artificial Intelligence in combination with the Internet of Medical Things enables remote healthcare services through networks of environmental and/or personal sensors. We present a remote healthcare service system which collects real-life data through an environmental sensor package, including binary motion, contact, pressure, and proximity sensors, installed at households of elderly people. Its aim is to keep the caregivers informed of subjects' health-status progressive trajectory, and alert them of health-related anomalies to enable objective on-demand healthcare service delivery at scale. The system was deployed in 19 households inhabited by an elderly person with post-stroke condition in the Emilia–Romagna region in Italy, with maximal and median observation durations of 98 and 55 weeks. Among these households, 17 were multi-occupancy residences, while the other 2 housed elderly patients living alone. Subjects' daily behavioral diaries were extracted and registered from raw sensor signals, using rule-based data pre-processing and unsupervised algorithms. Personal behavioral habits were identified and compared to typical patterns reported in behavioral science, as a quality-of-life indicator. We consider the activity patterns extracted across all users as a dictionary, and represent each patient's behavior as a 'Bag of Words', based on which patients can be categorized into sub-groups for precision cohort treatment. Longitudinal trends of the behavioral progressive trajectory and sudden abnormalities of a patient were detected and reported to care providers. Due to the sparse sensor setting and the multi-occupancy living condition, the sleep profile was used as the main indicator in our system. Experimental results demonstrate the ability to report on subjects' daily activity pattern in terms of sleep, outing, visiting, and health-status trajectories, as well as predicting/detecting 75% hospitalization sessions up to 11 days in advance. 65% of the alerts were confirmed to be semantically meaningful by the users. Furthermore, reduced social interaction (outing and visiting), and lower sleep quality could be observed during the COVID-19 lockdown period across the cohort. [ABSTRACT FROM AUTHOR]

This work presents a methodology to analyze and segment both seismocardiogram (SCG) and ballistocardiogram (BCG) signals in a unified fashion. An unsupervised approach is followed to extract a template of SCG/BCG heartbeats, which is then used to fine-tune temporal waveform annotation. Rigorous performance assessment is conducted in terms of sensitivity, precision, Root Mean Square Error (RMSE) and Mean Absolute Error (MAE) of annotation. The methodology is tested on four independent datasets, covering different measurement setups and time resolutions. A wide application range is therefore explored, which better characterizes the robustness and generality of the method with respect to a single dataset. Overall, sensitivity and precision scores are uniform across all datasets ( p > 0.05 from the Kruskal–Wallis test): the average sensitivity among datasets is 98.7%, with 98.2% precision. On the other hand, a slight yet significant difference in RMSE and MAE scores was found ( p < 0.01 ) in favor of datasets with higher sampling frequency. The best RMSE scores for SCG and BCG are 4.5 and 4.8 ms, respectively; similarly, the best MAE scores are 3.3 and 3.6 ms. The results were compared to relevant recent literature and are found to improve both detection performance and temporal annotation errors. [ABSTRACT FROM AUTHOR]

This paper presents an unsupervised methodology to analyze SeismoCardioGram (SCG) signals. Starting from raw accelerometric data, heartbeat complexes are extracted and annotated, using a two-step procedure. An unsupervised calibration procedure is added to better adapt to different user patterns. Results show that the performance scores achieved by the proposed methodology improve over related literature: on average, 98.5% sensitivity and 98.6% precision are achieved in beat detection, whereas RMS (Root Mean Square) error in heartbeat interval estimation is as low as 4.6 ms. This allows SCG heartbeat complexes to be reliably extracted. Then, the morphological information of such waveforms is further processed by means of a modular Convolutional Variational AutoEncoder network, aiming at extracting compressed, meaningful representation. After unsupervised training, the VAE network is able to recognize different signal morphologies, associating each user to its specific patterns with high accuracy, as indicated by specific performance metrics (including adjusted random and mutual information score, completeness, and homogeneity). Finally, a Linear Model is used to interpret the results of clustering in the learned latent space, highlighting the impact of different VAE architectural parameters (i.e., number of stacked convolutional units and dimension of latent space). [ABSTRACT FROM AUTHOR]

This paper introduces technical solutions devised to support the Deployment Site - Regione Emilia Romagna (DS-RER) of the ACTIVAGE project. The ACTIVAGE project aims at promoting IoT (Internet of Things)-based solutions for Active and Healthy ageing. DS-RER focuses on improving continuity of care for older adults (65+) suffering from aftereffects of a stroke event. A Wireless Sensor Kit based on Wi-Fi connectivity was suitably engineered and realized to monitor behavioral aspects, possibly relevant to health and wellbeing assessment. This includes bed/rests patterns, toilet usage, room presence and many others. Besides hardware design and validation, cloud-based analytics services are introduced, suitable for automatic extraction of relevant information (trends and anomalies) from raw sensor data streams. The approach is general and applicable to a wider range of use cases; however, for readability's sake, two simple cases are analyzed, related to bed and toilet usage patterns. In particular, a regression framework is introduced, suitable for detecting trends (long and short-term) and labeling anomalies. A methodology for assessing multi-modal daily behavioral profiles is introduced, based on unsupervised clustering techniques. The proposed framework has been successfully deployed at several real-users' homes, allowing for its functional validation. Clinical effectiveness will be assessed instead through a Randomized Control Trial study, currently being carried out. [ABSTRACT FROM AUTHOR]

Environmental sensors are exploited in smart homes for many purposes. Sensor data inherently carries behavioral information, possibly useful to infer wellness and health-related insights in an indirect fashion. In order to exploit such features, however, powerful analytics are needed to convert raw sensor output into meaningful and accessible knowledge. In this paper, a complete monitoring architecture is presented, including home sensors and cloud-based back-end services. Unsupervised techniques for behavioral data analysis are presented, including: (i) regression and outlier detection models (also used as feature extractors for more complex models); (ii) statistical hypothesis testing frameworks for detecting changes in sensor-detected activities; and (iii) a clustering process, leveraging deep learning techniques, for extracting complex, multivariate patterns from daily sensor data. Such methods are discussed and evaluated on real-life data, collected within several EU-funded projects. Overall, the presented methods may prove very useful to build effective monitoring services, suitable for practical exploitation in caregiving activities, complementing conventional telemedicine techniques. [ABSTRACT FROM AUTHOR]

Gate currents are becoming a major concern for ULSI circuit designers. A standard circuit design flow that takes into account such effects is needed in order to take advantage from nanometer-sized devices performance. Some suggestions on how to approach permeable-gate-device circuit simulation are proposed in this paper, focusing on gate-current-related effects on circuit performance. A simple, yet complete, standard CMOS circuit has been designed and its functional and performance indices have been evaluated, depending on the actual oxide thickness. To correlate performance directly to the fabrication parameters, a mixed-mode approach using both physical and circuit simulations has been adopted. Model parameters were calibrated on actual measurements. Simulation results have been compared for ideal- and permeable-gate devices. Although circuit functionality is not affected (within the considered technology range, at least), significant performance alterations are highlighted. [Copyright &y& Elsevier]

This work aims to compare the performance of Machine Learning (ML) and Deep Learning (DL) algorithms in detecting users' heartbeats on a smart bed. Targeting non-intrusive, continuous heart monitoring during sleep time, the smart bed is equipped with a 3D solid-state accelerometer. Acceleration signals are processed through an STM 32-bit microcontroller board and transmitted to a PC for recording. A photoplethysmographic sensor is simultaneously checked for ground truth reference. A dataset has been built, by acquiring measures in a real-world set-up: 10 participants were involved, resulting in 120 min of acceleration traces which were utilized to train and evaluate various Artificial Intelligence (AI) algorithms. The experimental analysis utilizes K-fold cross-validation to ensure robust model testing across different subsets of the dataset. Various ML and DL algorithms are compared, each being trained and tested using the collected data. The Random Forest algorithm exhibited the highest accuracy among all compared models. While it requires longer training time compared to some ML models such as Naïve Bayes, Linear Discrimination Analysis, and K-Nearest Neighbour Classification, it keeps substantially faster than Support Vector Machine and Deep Learning models. The Random Forest model demonstrated robust performance metrics, including recall, precision, F1-scores, macro average, weighted average, and overall accuracy well above 90%. The study highlights the better performance of the Random Forest algorithm for the specific use case, achieving superior accuracy and performance metrics in detecting user heartbeats in comparison to other ML and DL models tested. The drawback of longer training times is not too relevant in the long-term monitoring target scenario, so the Random Forest model stands out as a viable solution for real-time ballistocardiographic heartbeat detection, showcasing potential for healthcare and wellness monitoring applications.

Brain-Computer Interface (BCI) can provide users with an alternative/augmentative interaction path, based on the interpretation of their brain activity. Steady State Visual Evoked Potentials (SSVEP) paradigm has many appealing features, aiming at implementing BCI-enabled communication-control applications. In this paper, we present a complete signal processing chain for a self-paced, SSVEP-based BCI. The proposed approach mostly focuses at reducing the user effort in dealing with BCI, featuring no need of user-specific calibration or training. In this paper, the classification algorithm is introduced and first validated on offline waveforms, aiming at improving classification accuracy and minimizing the false positive rate. Then, implementation of an online, self-paced SSVEP BCI is illustrated. The scheme refers to a four-way choice and exploits discrimination between intentional control states and nocontrol ones. Good performance is achieved, both in terms of true positive rate (>94%), as well as low false positive rate (0.26 min(-1)), even in experiments carried out outside lab-controlled conditions.

EU population is getting older, so that ICT-based solutions are expected to provide support in the challenges implied by the demographic change. At the University of Parma an AAL (Ambient Assisted Living) system, named CARDEA, has been developed. In this paper a new feature of the system is introduced, in which environmental and personal (i.e., wearable) sensors coexist, providing an accurate picture of the user's activity and needs. Environmental devices may greatly help in performing activity recognition and behavioral analysis tasks. However, in a multi-user environment, this implies the need of attributing environmental sensors outcome to a specific user, i.e., identifying the user when he performs a task detected by an environmental device. We implemented such an "action tagging" feature, based on information fusion, within the CARDEA environment, as an inexpensive, alternative solution to the problematic issue of indoor locationing.