1,003 research outputs found

    User Identification Using Gait Patterns on UbiFloorII

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    This paper presents a system of identifying individuals by their gait patterns. We take into account various distinguishable features that can be extracted from a user’s gait and then divide them into two classes: walking pattern and stepping pattern. The conditions we assume are that our target environments are domestic areas, the number of users is smaller than 10, and all users ambulate with bare feet considering the everyday lifestyle of the Korean home. Under these conditions, we have developed a system that identifies individuals’ gait patterns using our biometric sensor, UbiFloorII. We have created UbiFloorII to collect walking samples and created software modules to extract the user’s gait pattern. To identify the users based on the gait patterns extracted from walking samples over UbiFloorII, we have deployed multilayer perceptron network, a feedforward artificial neural network model. The results show that both walking pattern and stepping pattern extracted from users’ gait over the UbiFloorII are distinguishable enough to identify the users and that fusing two classifiers at the matching score level improves the recognition accuracy. Therefore, our proposed system may provide unobtrusive and automatic user identification methods in ubiquitous computing environments, particularly in domestic areas

    Device-free indoor localisation with non-wireless sensing techniques : a thesis by publications presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Electronics and Computer Engineering, Massey University, Albany, New Zealand

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    Global Navigation Satellite Systems provide accurate and reliable outdoor positioning to support a large number of applications across many sectors. Unfortunately, such systems do not operate reliably inside buildings due to the signal degradation caused by the absence of a clear line of sight with the satellites. The past two decades have therefore seen intensive research into the development of Indoor Positioning System (IPS). While considerable progress has been made in the indoor localisation discipline, there is still no widely adopted solution. The proliferation of Internet of Things (IoT) devices within the modern built environment provides an opportunity to localise human subjects by utilising such ubiquitous networked devices. This thesis presents the development, implementation and evaluation of several passive indoor positioning systems using ambient Visible Light Positioning (VLP), capacitive-flooring, and thermopile sensors (low-resolution thermal cameras). These systems position the human subject in a device-free manner (i.e., the subject is not required to be instrumented). The developed systems improve upon the state-of-the-art solutions by offering superior position accuracy whilst also using more robust and generalised test setups. The developed passive VLP system is one of the first reported solutions making use of ambient light to position a moving human subject. The capacitive-floor based system improves upon the accuracy of existing flooring solutions as well as demonstrates the potential for automated fall detection. The system also requires very little calibration, i.e., variations of the environment or subject have very little impact upon it. The thermopile positioning system is also shown to be robust to changes in the environment and subjects. Improvements are made over the current literature by testing across multiple environments and subjects whilst using a robust ground truth system. Finally, advanced machine learning methods were implemented and benchmarked against a thermopile dataset which has been made available for other researchers to use

    Using movement sonification to alter body perception and promote physical activity in physically inactive people

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    Mención Internacional en el título de doctorWorldwide, one out of four adults are not physically active enough. Supporting people to be physically active through technology remains thus an important challenge in the field of Human-Computer Interaction (HCI). Some technologies have tried to tackle this challenge of increasing physical activity (PA) by using sensing devices for monitoring the amount and quality of PA and providing motivational feedback on it. However, such technologies provide very limited support to physically inactive users: while users are aware of their physical inactivity level, they are frequently incapable of acting on these problems by themselves. Among the reasons for it are negative perceptions about one’s body (e.g., feelings of body tiredness or weakness in self-esteem) which may act as psychological barriers to PA. This research project aims to address this limitation by employing an approach that, through movement sonification (i.e., real-time auditory feedback on body movement), exploits bottom-up multisensory mechanisms related to BPs to ultimately support PA. This thesis presents the design, development, and evaluation of SoniShoes and SoniBand, two wearable technological devices with a gesture-sound palette that allows for a range of body movement sonifications aimed to alter BPs. These prototypes aim at changing BPs, and in turn emotional state and movement behavior, to address psychological barriers related to the perception of one’s body, and ultimately impact positively on people’s adherence to PA. First, this work proposes to organize knowledge through a taxonomy of the barriers to PA related to body perception (BP), which follows a process of four steps to inform the design of the movement-sound palette: (1) Identification, (2) Extraction and clustering of attributes, (3) Definition of instructions or considerations, and (4) Strategies. The first two steps allowed the identification and grouping of barriers to PA that are related to BPs, with inputs from a literature review, a survey, and a focus group with HCI experts. The third and fourth steps allowed defining the body features and dimensions to act upon, to finally propose movement sonification strategies that have the potential to tackle the barriers. Second, several movement-sound mappings, based on metaphors, are presented. Movements were selected from exercises included in guidelines for becoming more physically active (e.g., walking). The mappings of these movements into sounds were implemented in SoniShoes and SoniBand prototypes. They were evaluated through an iterative process, starting with an exploratory study that tested for the first time the potential of the proposed mappings to change BPs. In this first study, participants were asked to think aloud about their experiences using the first prototype of SoniShoes (from MagicShoes project), by describing their body sensations and sound characteristics during the exercise. Results suggested the potential of movement sonification to alter BP through movement sonification and informed the design of the subsequent studies and prototypes. This exploratory study was followed by quantitative and qualitative studies aimed to understand how to design movement sonifications and wearable devices integrating them to facilitate PA by tackling barriers related to BP. The quantitative studies were controlled laboratory studies, in which different versions of SoniShoes and SoniBand prototypes were evaluated, and which results led to further iterations of the prototypes. The results of these quantitative evaluations revealed movement-sound mappings that can lead to changes in feelings about the body (e.g., feeling lighter or less tired), feelings about the movement (e.g., having more movement control over the movement), and emotional feelings (e.g., having more comfort, motivation to complete the exercise, or feeling happier) during PA. Results also showed effects of sound on movement behavior, such as effects in movement deceleration/acceleration and stance time, and proprioceptive awareness. Furthermore, two qualitative studies were carried out, which involved using the SoniBand prototype for several days and in two different contexts of use, laboratory and home. The aim of these studies was two-fold. First, elucidating the effects that particular metaphorical sonifications’ qualities and characteristics have on people’s perception of their own body and their PA. Second, understanding how the observed effects may be specific to physically inactive (vs. active) populations. The results revealed specific connections between properties of the movement sonifications (e.g., gradual or frequency changes) on the one hand, and particular body feelings (e.g., feeling strong) and aspects of PA (e.g., repetitions) on the other hand, but effects seem to vary according to the PA-level of the populations. Finally, the findings, contributions, and principles for the design of movement sonifications and wearable technology to promote PA through acting upon BP are discussed, finishing by considering implications for potential interventions and applications supporting PA, as well as opportunities opened for future research.En todo el mundo, uno de cada cuatro adultos no es lo suficientemente activo físicamente. Por ello, ayudar a las personas a ser físicamente activas a través de la tecnología sigue siendo un reto importante en el campo de “Human-Computer Interaction” (HCI). Algunas tecnologías han tratado de abordar el reto de aumentar la actividad física (PA) mediante el uso de dispositivos de detección para controlar la cantidad y la calidad de la PA y proporcionar retroalimentación motivacional al respecto. Sin embargo, estas tecnologías proporcionan una ayuda muy limitada a los usuarios físicamente inactivos: aunque los usuarios son conscientes de su nivel de inactividad física, a menudo son incapaces de actuar por sí mismos sobre estos problemas. Entre las razones están las percepciones negativas sobre el propio cuerpo (por ejemplo, la sensación de cansancio corporal o el no sentirse capaces) que pueden actuar como barreras psicológicas para la PA. Este proyecto de investigación pretende abordar esta limitación empleando un enfoque que, a través de la sonificación del movimiento (es decir, la retroalimentación auditiva en tiempo real sobre el movimiento del cuerpo), explota los mecanismos “bottom-up” multisensoriales relacionados con las percepciones del cuerpo (BPs) para apoyar la PA. Esta tesis presenta el diseño, el desarrollo y la evaluación de “SoniShoes” y “SoniBand”, dos dispositivos tecnológicos vestibles con una paleta de gestos y sonidos que permiten una serie de sonificaciones del movimiento corporal destinadas a modificar las BPs. Estos prototipos tienen como objetivo cambiar las BPs, y a su vez el estado emocional y el comportamiento de movimiento, para abordar las barreras psicológicas relacionadas con la BP, y en última instancia impactar positivamente en la adherencia de las personas a la PA. En primer lugar, este trabajo propone organizar el conocimiento a través de una taxonomía de las barreras a la PA relacionadas con la BP, que sigue un proceso de cuatro pasos para informar el diseño de la paleta de movimiento-sonido: (1) Identificación, (2) Extracción y agrupación de atributos, (3) Definición de instrucciones o consideraciones, y (4) Estrategias. Los dos primeros pasos permitieron identificar y agrupar las barreras a la PA relacionadas con los BP, con aportaciones de una revisión bibliográfica, una encuesta y un grupo de discusión con expertos en HCI. El tercero y cuarto paso permitió definir las características y dimensiones corporales sobre las que actuar, para finalmente proponer estrategias de sonificación del movimiento que tienen el potencial de abordar las barreras. En segundo lugar, se presentan varios mapeos de movimiento-sonido, basados en metáforas. Los movimientos se seleccionaron a partir de ejercicios incluidos en las guías para ser más activos físicamente (por ejemplo, caminar). Los mapeos de estos movimientos en sonidos se implementaron en los prototipos “SoniShoes” y “SoniBand”. Se evaluaron a través de un proceso iterativo, comenzando con un estudio exploratorio que probó por primera vez el potencial de los mapeos propuestos para cambiar los BP. En este primer estudio, se pidió a los participantes que pensaran en voz alta sobre sus experiencias utilizando el primer prototipo de “SoniShoes” (llamado “MagicShoes”), describiendo sus sensaciones corporales y las características del sonido durante el ejercicio. Los resultados mostraron el potencial de la sonificación del movimiento para alterar la BP a través de la sonificación del movimiento e informaron el diseño de los estudios y prototipos posteriores. A este estudio exploratorio le siguieron estudios cuantitativos y cualitativos destinados a comprender cómo diseñar sonificaciones del movimiento y dispositivos vestibles que las integren para facilitar la PA abordando las barreras relacionadas con la BP. Los estudios cuantitativos fueron estudios de laboratorio controlados, en los que se evaluaron diferentes versiones de los prototipos “SoniShoes” y “SoniBand”, y cuyos resultados condujeron a nuevas iteraciones de los prototipos. Los resultados de estas evaluaciones cuantitativas mostraron que existen mapeos de movimiento-sonido que pueden provocar cambios en las sensaciones sobre el cuerpo (por ejemplo, sentirse más ligero o menos cansado), en las sensaciones sobre el movimiento (por ejemplo, tener más control sobre el movimiento) y en las sensaciones emocionales (por ejemplo, tener más comodidad, motivación para completar el ejercicio o sentirse más feliz) durante la PA. Los resultados también mostraron los efectos del sonido en el comportamiento del movimiento, como los efectos en la desaceleración/aceleración del movimiento y el tiempo de postura, y la conciencia propioceptiva. Además, se llevaron a cabo dos estudios cualitativos, en los que se utilizó el prototipo “SoniBand” durante varios días y en dos contextos de uso diferentes, el laboratorio y el hogar. El objetivo de estos estudios era doble. En primer lugar, dilucidar los efectos que determinadas cualidades y características de las sonificaciones con metáforas tienen en la percepción que las personas tienen de su propio cuerpo y de su PA. En segundo lugar, comprender cómo los efectos observados pueden ser específicos de las poblaciones físicamente inactivas (vs. las activas). Los resultados revelaron conexiones específicas entre las propiedades de las sonificaciones de movimiento (por ejemplo, los cambios graduales o de frecuencia) por un lado, y las sensaciones corporales particulares (por ejemplo, sentirse fuerte) y los aspectos de la PA (por ejemplo, las repeticiones) por otro lado, pero los efectos parecen variar según el nivel de PA de las poblaciones. Por último, se discuten los hallazgos, las contribuciones y las guías de diseño de sonificación de movimiento y tecnología vestible para promover la PA a través de la actuación sobre la BP, para finalmente considerar las implicaciones para las posibles intervenciones y aplicaciones de apoyo a la PA, así como las oportunidades abiertas para futuras investigaciones.I owe thanks to “MAGIC SHOES” (PSI2016-79004-R and BES-2017-080471) and “CROSS-COLAB” (PGC2018-101884-B-I00) projects that funded my research. Thanks to “MAGIC OUTFIT” (PID2019-105579RB-I00) for letting me be part of the team and project.Programa de Doctorado en Ciencia y Tecnología Informática por la Universidad Carlos III de MadridPresidente: Paloma Martínez Fernández.- Secretario: Domna Banakou.- Vocal: Mar González Franc

    Scattering Features for Multimodal Gait Recognition

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    International audienceWe consider the problem of identifying people on the basis of their walk (gait) pattern. Classical approaches to tackle this problem are based on, e.g., video recordings or piezoelec-tric sensors embedded in the floor. In this work, we rely on acoustic and vibration measurements, obtained from a microphone and a geophone sensor, respectively. The contribution of this work is twofold. First, we propose a feature extraction method based on an (untrained) shallow scattering network, specially tailored for the gait signals. Second, we demonstrate that fusing the two modalities improves identification in the practically relevant open set scenario

    Integrating passive ubiquitous surfaces into human-computer interaction

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    Mobile technologies enable people to interact with computers ubiquitously. This dissertation investigates how ordinary, ubiquitous surfaces can be integrated into human-computer interaction to extend the interaction space beyond the edge of the display. It turns out that acoustic and tactile features generated during an interaction can be combined to identify input events, the user, and the surface. In addition, it is shown that a heterogeneous distribution of different surfaces is particularly suitable for realizing versatile interaction modalities. However, privacy concerns must be considered when selecting sensors, and context can be crucial in determining whether and what interaction to perform.Mobile Technologien ermöglichen den Menschen eine allgegenwärtige Interaktion mit Computern. Diese Dissertation untersucht, wie gewöhnliche, allgegenwärtige Oberflächen in die Mensch-Computer-Interaktion integriert werden können, um den Interaktionsraum über den Rand des Displays hinaus zu erweitern. Es stellt sich heraus, dass akustische und taktile Merkmale, die während einer Interaktion erzeugt werden, kombiniert werden können, um Eingabeereignisse, den Benutzer und die Oberfläche zu identifizieren. Darüber hinaus wird gezeigt, dass eine heterogene Verteilung verschiedener Oberflächen besonders geeignet ist, um vielfältige Interaktionsmodalitäten zu realisieren. Bei der Auswahl der Sensoren müssen jedoch Datenschutzaspekte berücksichtigt werden, und der Kontext kann entscheidend dafür sein, ob und welche Interaktion durchgeführt werden soll

    Gait and Locomotion Analysis for Tribological Applications

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