Latest research trends in gait analysis using wearable sensors and machine learning: a systematic review

Gait is the locomotion attained through the movement of limbs and gait analysis examines the patterns (normal/abnormal) depending on the gait cycle. It contributes to the development of various applications in the medical, security, sports, and fitness domains to improve the overall outcome. Among many available technologies, two emerging technologies that play a central role in modern day gait analysis are: A) wearable sensors which provide a convenient, efficient, and inexpensive way to collect data and B) Machine Learning Methods (MLMs) which enable high accuracy gait feature extraction for analysis. Given their prominent roles, this paper presents a review of the latest trends in gait analysis using wearable sensors and Machine Learning (ML). It explores the recent papers along with the publication details and key parameters such as sampling rates, MLMs, wearable sensors, number of sensors, and their locations. Furthermore, the paper provides recommendations for selecting a MLM, wearable sensor and its location for a specific application. Finally, it suggests some future directions for gait analysis and its applications

Estimation, filtering and fusion for networked systems with network-induced phenomena: New progress and prospects

In this paper, some recent advances on the estimation, filtering and fusion for networked systems are reviewed. Firstly, the network-induced phenomena under consideration are briefly recalled including missing/fading measurements, signal quantization, sensor saturations, communication delays, and randomly occurring incomplete information. Secondly, the developments of the estimation, filtering and fusion for networked systems from four aspects (linear networked systems, nonlinear networked systems, complex networks and sensor networks) are reviewed comprehensively. Subsequently, some recent results on the estimation, filtering and fusion for systems with the network-induced phenomena are reviewed in great detail. In particular, some latest results on the multi-objective filtering problems for time-varying nonlinear networked systems are summarized. Finally, conclusions are given and several possible research directions concerning the estimation, filtering, and fusion for networked systems are highlighted

Continuous Authentication using Inertial-Sensors of Smartphones and Deep Learning

The legitimacy of users is of great importance for the security of information systems. The authentication process is a trade-off between system security and user experience. E.g., forced password complexity or multi-factor authentication can increase protection, but the application becomes more cumbersome for the users. Therefore, it makes sense to investigate whether the identity of a user can be verified reliably enough, without his active participation, to replace or supplement existing login processes. This master thesis examines if the inertial sensors of a smartphone can be leveraged to continuously determine whether the device is currently in possession of its legitimate owner or by another person. To this end, an approach proposed in related studies will be implemented and examined in detail. This approach is based on the use of a so-called Siamese artificial neural network to transform the measured values of the sensors into a new vector that can be classified more reliably. It is demonstrated that the reported results of the proposed approach can be reproduced under certain conditions. However, if the same model is used under conditions that are closer to a real-world application, its reliability decreases significantly. Therefore, a variant of the proposed approach is derived whose results are superior to the original model under real conditions. The thesis concludes with concrete recommendations for further development of the model and provides methodological suggestions for improving the quality of research in the topic of "Continuous Authentication".Für die Sicherheit von Informationssystemen ist die Legitimierung der Nutzer von großer Bedeutung. Der Authentifizierungsprozess ist dabei eine Gratwanderung zwischen Sicherheit des Systems und Benutzerfreundlichkeit. So können etwa erzwungene Passwortkomplexität oder Multi-Faktor-Authentifizierung den Schutz erhöhen, für Anwender wird die Bedienung jedoch umständlicher. Daher stellt sich die Frage, ob die Identität des Nutzers auch ohne seine aktive Mitwirkung zuverlässig genug verifiziert werden kann, um dadurch Anmeldeprozesse sinnvoll ersetzen oder ergänzen zu können. In dieser Masterarbeit wird die Frage untersucht, ob mithilfe der Inertialsensoren eines Smartphones kontinuierlich ermittelt werden kann, ob sich das Gerät gerade in Besitz seines rechtmäßigen Eigentümers befindet, oder von einem Dritten getragen wird. Hierzu wird ein in der Forschungsliteratur vorgeschlagener Ansatz nach implementiert und genauer untersucht. Der Ansatz basiert auf der Verwendung eines sogenannten siamesischen künstlichen neuronalen Netzwerks, um die Messwerte der Sensoren in einen anderen Vektor zu transformieren, der zuverlässiger klassifiziert werden kann. Im Ergebnis wird gezeigt, dass sich die berichteten Ergebnisse des vorgeschlagenen Ansatzes unter bestimmten Voraussetzungen reproduzieren lassen. Wird das gleiche Modell unter Bedingungen eingesetzt, die einer realen Anwendung näher kommen, nimmt die Zuverlässigkeit jedoch massiv ab. Daher wird eine Variante des genutzten Ansatzes hergeleitet, deren Ergebnisse dem ursprünglichen Modell unter realen Bedingungen überlegen sind. Die Arbeit schließt mit konkreten Empfehlungen zur Weiterentwicklung des Modells und gibt methodische Anregungen zur Qualitätssteigerung der Forschung in diesem Themenfeld der "Continuous Authentication"

Applications in Electronics Pervading Industry, Environment and Society

This book features the manuscripts accepted for the Special Issue “Applications in Electronics Pervading Industry, Environment and Society—Sensing Systems and Pervasive Intelligence” of the MDPI journal Sensors. Most of the papers come from a selection of the best papers of the 2019 edition of the “Applications in Electronics Pervading Industry, Environment and Society” (APPLEPIES) Conference, which was held in November 2019. All these papers have been significantly enhanced with novel experimental results. The papers give an overview of the trends in research and development activities concerning the pervasive application of electronics in industry, the environment, and society. The focus of these papers is on cyber physical systems (CPS), with research proposals for new sensor acquisition and ADC (analog to digital converter) methods, high-speed communication systems, cybersecurity, big data management, and data processing including emerging machine learning techniques. Physical implementation aspects are discussed as well as the trade-off found between functional performance and hardware/system costs

A postural information‐based biometric authentication system employing S‐transform, radial basis function network, and extended Kalman filtering

International audienceThis paper proposes a new system for biometry-based human authentication, where postural signal information is utilized to identify a person. The system employs a novel approach where four types of temporal postural signals are acquired for each person to develop an authentication database, and for each posture, both signals in the - and -directions are utilized for the purpose of authentication. The proposed system utilizes S-transform, which is a joint time-frequency representation tool, to determine the characteristic features for each human posture. Based on these characteristic features, a radial basis function network (RBFN) system is developed for the purpose of specific authentication. The RBFN authentication system is developed by training it to employ extended Kalman filtering (EKF). The EKF-trained RBFN authentication system could produce overall authentication accuracy on the order of 94%-95% and could outperform similar authentication systems developed, which employ two very popular variants of backpropagation neural networks (BPNNs) and a variant of radial basis neural network (RBNN)

Signal Processing Using Non-invasive Physiological Sensors

Non-invasive biomedical sensors for monitoring physiological parameters from the human body for potential future therapies and healthcare solutions. Today, a critical factor in providing a cost-effective healthcare system is improving patients' quality of life and mobility, which can be achieved by developing non-invasive sensor systems, which can then be deployed in point of care, used at home or integrated into wearable devices for long-term data collection. Another factor that plays an integral part in a cost-effective healthcare system is the signal processing of the data recorded with non-invasive biomedical sensors. In this book, we aimed to attract researchers who are interested in the application of signal processing methods to different biomedical signals, such as an electroencephalogram (EEG), electromyogram (EMG), functional near-infrared spectroscopy (fNIRS), electrocardiogram (ECG), galvanic skin response, pulse oximetry, photoplethysmogram (PPG), etc. We encouraged new signal processing methods or the use of existing signal processing methods for its novel application in physiological signals to help healthcare providers make better decisions

Biomechatronics: Harmonizing Mechatronic Systems with Human Beings

This eBook provides a comprehensive treatise on modern biomechatronic systems centred around human applications. A particular emphasis is given to exoskeleton designs for assistance and training with advanced interfaces in human-machine interaction. Some of these designs are validated with experimental results which the reader will find very informative as building-blocks for designing such systems. This eBook will be ideally suited to those researching in biomechatronic area with bio-feedback applications or those who are involved in high-end research on manmachine interfaces. This may also serve as a textbook for biomechatronic design at post-graduate level

Principal Component Analysis

This book is aimed at raising awareness of researchers, scientists and engineers on the benefits of Principal Component Analysis (PCA) in data analysis. In this book, the reader will find the applications of PCA in fields such as image processing, biometric, face recognition and speech processing. It also includes the core concepts and the state-of-the-art methods in data analysis and feature extraction