Study of the Motor Cognitive Interaction During Walking Using Transcranial Doppler

Gait is a complex process involving both cognitive and sensory ability and is strongly impacted by the environment. In this thesis, we propose the study of the impact on cognitive task during gait on the cerebral blood flow velocity through a dual task methodology. Both cerebral blood flow velocity and gait characteristics of eleven participants with no history of brain or gait conditions were recorded using transcranial Doppler on mid-cerebral artery and a treadmill. The cognitive task was induced by a backward counting starting from 10,000 with decrement of 7. Central blood flow velocity raw and envelope features were extracted in both time, frequency and time-scale domain along with information-theoretic metrics were extracted, and statistical significances. A similar feature extraction was performed on the stride interval signal. Statistical differences between the cognitive and baseline trials, between the left and right mid-cerebral arteries signals and the impact of the anthropometric variables where studied using linear mixed models. No statistical differences were found between the left and right mid-cerebral arteries flows or the baseline and cognitive state gait features, while statistical differences for specific features were measured between cognitive and baseline states. These statistical differences found between the baseline and cognitive states show that cognitive process has an impact on the cerebral activity during walking. The state was found to have an impact on the correlation between the gait and blood flow features

Des services intelligents à partir d’objets connectés réutilisables et adaptables : Applications aux réseaux non-intrusifs de capteurs biomédicaux portables

The rapid growth of fixed and mobile smart objects raises the issue of their integration in everyday environment, e.g. in e-health or home-automation contexts. The main challenges of these objects are the interoperability, the handling of the massive amount of data that they generate, and their limited resources. Our goal is to take a bottom-up approach in order to improve the integration of smart devices to smart services. To ensure the efficient development of our approach, we start with the study of the design process of such devices regardless of specific hardware or software through the consideration of their cyber-physical properties. We thus develop two research directions: the specification of a service-oriented design method for smart devices with formal considerations in order to validate their behavior, and the proposal of a self-adaptation framework in order to handle changing operating context through self-reasoning and the definition of a declarative self-adaptation objectives specification language. The testing of these contributions will be realized through the development of a large-scale experimental framework based on a remote diagnostics case-study relying on non-invasive wearable biomedical sensors.La prolifération des objets communicants fixes et mobiles soulève la question de leur intégration dans les environnements quotidiens, par exemple dans le cadre de la e-santé ou de la domotique. Les principaux défis soulevés relèvent de l’interconnexion et de la gestion de la masse de donnée produite par ces objets intelligents. Notre premier objectif est d’adopter une démarche des couches basses vers les couches hautes pour faciliter l’intégration de ces objets à des services intelligents. Afin de développer celle-ci, il est nécessaire de d’étudier le processus de conception des objets intelligents indépendamment de considérations matérielles et logicielles, au travers de la considération de leur propriétés cyber-physiques. Pour mener à bien la réalisation de services intelligents à partir d’objets connectés, les deux axes de recherche suivant seront développés : la définition d’une méthode de conception orientée service pour les objets connectés intégrant une dimension formelle ainsi de valider le comportement de ceux-ci, l’auto-adaptation intelligente dans un contexte évolutif permettant aux objets de raisonner sur eux même au travers d’un langage déclaratif pour spécifier les stratégies d’adaptation. La validation de ces contributions s’effectuera par le biais du développement et de l’expérimentation à grandeur nature d’un service de diagnostic médical continu basé sur la collecte de données médicales en masse par des réseaux non-intrusifs de capteurs biomédicaux portables sur le corps humain

Verifiable and Resource-Aware Component Model for IoT Devices

International audienceMost connected objects feature very limited capabilities that present challenges in terms of data processing and connectivity. In addition, heterogeneity of smart Internet-of-Things devices also causes interoperability problems. These limitations lead to strong hard- ware and software constraints that must be considered as early as possible during the design process. In this paper, we introduce a smart object component-based model to build complex smart objects by composition mechanisms in a similar way to Web service compositions. The smart object model extends artifact types and describes its structure and behavior in terms of attribute value pair, state-based lifecycle and services. Moreover, we propose a formal specification based on the intuitive multiplicative segment of intuitionistic linear logic not only to express consumable resources but also to automate composition from logical proofs

Smart and Safe Self-Adaption of Connected Devices Based on Discrete Controllers

International audienceThe Internet-of-things, which designates the interconnection of physical objects, is a growing research area with many challenges. One of these challenges is the management of failures and unforeseen situations when using connected devices in real world applications. To this end, the authors propose a self-adaptation framework to deal with changes and take into account storage, computational and communication constraints. Their self-adaptation framework relies on constraints expressed in terms of quality of service (QoS) and event-driven rules to specify control objectives. Internally, the framework generates labelled transitions systems and builds on the fly synchronous controllers to guarantee QoS properties. Moreover, their framework has capabilities to concurrently deal with dynamic control objectives, monitoring and self-adaptation. To prove the practicality of their framework, they present a healthcare case-study to remotely monitor a patient at risk of myocardial infarction recurrence. The objective control rules easily specify how wearable devices should coordinate their behaviours to ensure safety, resilience and health-awareness factors. The implementation of their framework is fully distributed and scalable and include their development of a wearable, remotely configurable, QoS aware cardiac activity sensor

Hybrid Controller Synthesis for the IoT

International audienceThe Internet-of-Things designates the interconnection of a variety of communication-enabled physical objects, and IoT-based systems and devices must operate with a deterministic behavior and respect user-defined system goals in any situation. We thus defined hybrid controller synthesis for decentralized and critical IoT-based systems relying on a set of rules to handle situations with asynchronous and synchronous event processing. This framework defines a declarative rule-driven governance mechanism of locally synchronous subsystems enabling the hybrid control of IoT systems with formal guarantees of the satisfaction of system-wide QoS requirements. In order to prove the practicality of our framework, then applied if to a critical medical Internet-of-Things use case, demonstrating its usability for critical IoT application

Internet of Medical Things: A Review of Recent Contributions Dealing with Cyber-Physical Systems in Medicine

International audienceThe Internet of Medical Things designates the interconnection of communication-enabled medical-grade devices and their integration to wider-scale health networks in order to improve patients’ health. However, because of the critical nature of health-related systems, the Internet of Medical Things still faces numerous challenges, more particularly in terms of reliability, safety and security. In this paper, we present a comprehensive literature review of recent contributions focused on improving the Internet of Medical Things through the use of formal methodologies provided by the cyber-physical systems community. We describe the practical application of the democratization of medical devices for both patients and health-care providers. We also identify unexplored research directions and potential trends to solve uncharted research problems

Evaluation of a real-time low-power cardiorespiratory sensor for the IoT

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Building IoT-Enabled Wearable Medical Devices: An Application to a Wearable, Multiparametric, Cardiorespiratory Sensor

International audienceRecent developments in personal and mobile healthcare have shown promising results in term of patients' quality of life and quality of care improvements. This can be achieved through continuous monitoring of patients' physiological functions using wearable non-invasive biomedical sensors. The remote collection and processing of such data can then be used to provide rapid medical response if a problem is detected or to offer preventive measures. However, the integration of wearable sensors into wider-scale framework is still a major challenge, as real-time data collection and remote configuration capabilities must be integrated to strongly constrained devices. Here, we show how such requirements can be integrated into a multiparameter, cardiorespiratory wearable sensor and how this sensor can be integrated into wide-scale Internet-based frameworks. We thus manufactured a biomedical-grade heart rate, instantaneous heart-rate variability and respiratory sensor. The sensor was tested in real life ambulatory condition, and we showed an Internet-based proof of concept exhibiting the integration of our sensor into wide-scale healthcare frameworks. Finally, we anticipate that wearable healthcare will greatly improve patients' quality-of-life by using IoT-based wearable devices similar to the sensor developed in this paper

Analysis of the pen pressure and grip force signal during basic drawing tasks: The timing and speed changes impact drawing characteristics

International audienceWriting is a complex fine and trained motor skill, involving complex biomechanical and cognitive processes. In this paper, we propose the study of writing kinetics using three angles: the pen-tip normal force, the total grip force signal and eventually writing quality assessment. In order to collect writing kinetics data, we designed a sensor collecting these characteristics simultaneously. Ten healthy right-handed adults were recruited and were asked to perform four tasks: first, they were instructed to draw circles at a speed they considered comfortable; they then were instructed to draw circles at a speed they regarded as fast; afterwards, they repeated the comfortable task compelled to follow the rhythm of a metronome; and eventually they performed the fast task under the same timing constraints. Statistical differences between the tasks were computed, and while pen-tip normal force and total grip force signal were not impacted by the changes introduced in each task, writing quality features were affected by both the speed changes and timing constraint changes. This verifies the already-studied speed-accuracy trade-off and suggest the existence of a timing constraints-accuracy trade-off