833 research outputs found

    Comparative analysis of energy transfer mechanisms for neural implants

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    As neural implant technologies advance rapidly, a nuanced understanding of their powering mechanisms becomes indispensable, especially given the long-term biocompatibility risks like oxidative stress and inflammation, which can be aggravated by recurrent surgeries, including battery replacements. This review delves into a comprehensive analysis, starting with biocompatibility considerations for both energy storage units and transfer methods. The review focuses on four main mechanisms for powering neural implants: Electromagnetic, Acoustic, Optical, and Direct Connection to the Body. Among these, Electromagnetic Methods include techniques such as Near-Field Communication (RF). Acoustic methods using high-frequency ultrasound offer advantages in power transmission efficiency and multi-node interrogation capabilities. Optical methods, although still in early development, show promising energy transmission efficiencies using Near-Infrared (NIR) light while avoiding electromagnetic interference. Direct connections, while efficient, pose substantial safety risks, including infection and micromotion disturbances within neural tissue. The review employs key metrics such as specific absorption rate (SAR) and energy transfer efficiency for a nuanced evaluation of these methods. It also discusses recent innovations like the Sectored-Multi Ring Ultrasonic Transducer (S-MRUT), Stentrode, and Neural Dust. Ultimately, this review aims to help researchers, clinicians, and engineers better understand the challenges of and potentially create new solutions for powering neural implants

    Improving diagnostic procedures for epilepsy through automated recording and analysis of patients’ history

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    Transient loss of consciousness (TLOC) is a time-limited state of profound cognitive impairment characterised by amnesia, abnormal motor control, loss of responsiveness, a short duration and complete recovery. Most instances of TLOC are caused by one of three health conditions: epilepsy, functional (dissociative) seizures (FDS), or syncope. There is often a delay before the correct diagnosis is made and 10-20% of individuals initially receive an incorrect diagnosis. Clinical decision tools based on the endorsement of TLOC symptom lists have been limited to distinguishing between two causes of TLOC. The Initial Paroxysmal Event Profile (iPEP) has shown promise but was demonstrated to have greater accuracy in distinguishing between syncope and epilepsy or FDS than between epilepsy and FDS. The objective of this thesis was to investigate whether interactional, linguistic, and communicative differences in how people with epilepsy and people with FDS describe their experiences of TLOC can improve the predictive performance of the iPEP. An online web application was designed that collected information about TLOC symptoms and medical history from patients and witnesses using a binary questionnaire and verbal interaction with a virtual agent. We explored potential methods of automatically detecting these communicative differences, whether the differences were present during an interaction with a VA, to what extent these automatically detectable communicative differences improve the performance of the iPEP, and the acceptability of the application from the perspective of patients and witnesses. The two feature sets that were applied to previous doctor-patient interactions, features designed to measure formulation effort or detect semantic differences between the two groups, were able to predict the diagnosis with an accuracy of 71% and 81%, respectively. Individuals with epilepsy or FDS provided descriptions of TLOC to the VA that were qualitatively like those observed in previous research. Both feature sets were effective predictors of the diagnosis when applied to the web application recordings (85.7% and 85.7%). Overall, the accuracy of machine learning models trained for the threeway classification between epilepsy, FDS, and syncope using the iPEP responses from patients that were collected through the web application was worse than the performance observed in previous research (65.8% vs 78.3%), but the performance was increased by the inclusion of features extracted from the spoken descriptions on TLOC (85.5%). Finally, most participants who provided feedback reported that the online application was acceptable. These findings suggest that it is feasible to differentiate between people with epilepsy and people with FDS using an automated analysis of spoken seizure descriptions. Furthermore, incorporating these features into a clinical decision tool for TLOC can improve the predictive performance by improving the differential diagnosis between these two health conditions. Future research should use the feedback to improve the design of the application and increase perceived acceptability of the approach

    Beam scanning by liquid-crystal biasing in a modified SIW structure

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    A fixed-frequency beam-scanning 1D antenna based on Liquid Crystals (LCs) is designed for application in 2D scanning with lateral alignment. The 2D array environment imposes full decoupling of adjacent 1D antennas, which often conflicts with the LC requirement of DC biasing: the proposed design accommodates both. The LC medium is placed inside a Substrate Integrated Waveguide (SIW) modified to work as a Groove Gap Waveguide, with radiating slots etched on the upper broad wall, that radiates as a Leaky-Wave Antenna (LWA). This allows effective application of the DC bias voltage needed for tuning the LCs. At the same time, the RF field remains laterally confined, enabling the possibility to lay several antennas in parallel and achieve 2D beam scanning. The design is validated by simulation employing the actual properties of a commercial LC medium

    A Cybersecurity review of Healthcare Industry

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    Antecedentes La ciberseguridad no es un concepto nuevo de nuestros días. Desde los años 60 la ciberseguridad ha sido un ámbito de discusión e investigación. Aunque los mecanismos de defensa en materia de seguridad han evolucionado, las capacidades del atacante también se han incrementado de igual o mayor manera. Prueba de este hecho es la precaria situación en materia de ciberseguridad de muchas empresas, que ha llevado a un incremento de ataques de ransomware y el establecimiento de grandes organizaciones criminales dedicadas al cibercrimen. Esta situación, evidencia la necesidad de avances e inversión en ciberseguridad en multitud de sectores, siendo especialmente relevante en la protección de infraestructuras críticas. Se conoce como infraestructuras críticas aquellas infraestructuras estratégicas cuyo funcionamiento es indispensable y no permite soluciones alternativas, por lo que su perturbación o destrucción tendría un grave impacto sobre los servicios esenciales. Dentro de esta categorización se encuentran los servicios e infraestructuras sanitarias. Estas infraestructuras ofrecen un servicio, cuya interrupción conlleva graves consecuencias, como la pérdida de vidas humanas. Un ciberataque puede afectar a estos servicios sanitarios, llevando a su paralización total o parcial, como se ha visto en recientes incidentes, llevando incluso a la pérdida de vidas humanas. Además, este tipo de servicios contienen multitud de información personal de carácter altamente sensible. Los datos médicos son un tipo de datos con alto valor en mercados ilegales, y por tanto objetivos de ataques centrados en su robo. Por otra parte, se debe mencionar, que al igual que otros sectores, actualmente los servicios sanitarios se encuentran en un proceso de digitalización. Esta evolución, ha obviado la ciberseguridad en la mayoría de sus desarrollos, contribuyendo al crecimiento y gravedad de los ataques previamente mencionados. - Metodología e investigación El trabajo presentado en esta tesis sigue claramente un método experimental y deductivo. Está investigación se ha centrado en evaluar el estado de la ciberseguridad en infraestructuras sanitarias y proponer mejoras y mecanismos de detección de ciberataques. Las tres publicaciones científicas incluidas en esta tesis buscan dar soluciones y evaluar problemas actuales en el ámbito de las infraestructuras y sistemas sanitarios. La primera publicación, 'Mobile malware detection using machine learning techniques', se centró en desarrollar nuevas técnicas de detección de amenazas basadas en el uso de tecnologías de inteligencia artificial y ‘machine learning’. Esta investigación fue capaz de desarrollar un método de detección de aplicaciones potencialmente no deseadas y maliciosas en entornos móviles de tipo Android. Además, tanto en el diseño y creación se tuvo en cuenta las necesidades específicas de los entornos sanitarios. Buscando ofrecer una implantación sencilla y viable de acorde las necesidades de estos centros, obteniéndose resultados satisfactorios. La segunda publicación, 'Interconnection Between Darknets', buscaba identificar y detectar robos y venta de datos médicos en darknets. El desarrollo de esta investigación conllevó el descubrimiento y prueba de la interconexión entre distintas darknets. La búsqueda y el análisis de información en este tipo de redes permitió demostrar como distintas redes comparten información y referencias entre ellas. El análisis de una darknet implica la necesidad de analizar otras, para obtener una información más completa de la primera. Finalmente, la última publicación, 'Security and privacy issues of data-over-sound technologies used in IoT healthcare devices' buscó investigar y evaluar la seguridad de dispositivos médicos IoT ('Internet of Things'). Para desarrollar esta investigación se adquirió un dispositivo médico, un electrocardiógrafo portable, actualmente en uso por diversos hospitales. Las pruebas realizadas sobre este dispositivo fueron capaces de descubrir múltiples fallos de ciberseguridad. Estos descubrimientos evidenciaron la carencia de certificaciones y revisiones obligatorias en materia ciberseguridad en productos sanitarios, comercializados actualmente. Desgraciadamente la falta de presupuesto dedicado a investigación no permitió la adquisición de varios dispositivos médicos, para su posterior evaluación en ciberseguridad. - Conclusiones La realización de los trabajos e investigaciones previamente mencionadas permitió obtener las siguientes conclusiones. Partiendo de la necesidad en mecanismos de ciberseguridad de las infraestructuras sanitarias, se debe tener en cuenta su particularidad diseño y funcionamiento. Las pruebas y mecanismos de ciberseguridad diseñados han de ser aplicables en entornos reales. Desgraciadamente actualmente en las infraestructuras sanitarias hay sistemas tecnológicos imposibles de actualizar o modificar. Multitud de máquinas de tratamiento y diagnostico cuentan con software y sistemas operativos propietarios a los cuales los administradores y empleados no tienen acceso. Teniendo en cuenta esta situación, se deben desarrollar medidas que permitan su aplicación en este ecosistema y que en la medida de los posible puedan reducir y paliar el riesgo ofrecido por estos sistemas. Esta conclusión viene ligada a la falta de seguridad en dispositivos médicos. La mayoría de los dispositivos médicos no han seguido un proceso de diseño seguro y no han sido sometidos a pruebas de seguridad por parte de los fabricantes, al suponer esto un coste directo en el desarrollo del producto. La única solución en este aspecto es la aplicación de una legislación que fuerce a los fabricantes a cumplir estándares de seguridad. Y aunque actualmente se ha avanzado en este aspecto regulatorio, se tardaran años o décadas en sustituir los dispositivos inseguros. La imposibilidad de actualizar, o fallos relacionados con el hardware de los productos, hacen imposible la solución de todos los fallos de seguridad que se descubran. Abocando al reemplazo del dispositivo, cuando exista una alternativa satisfactoria en materia de ciberseguridad. Por esta razón es necesario diseñar nuevos mecanismos de ciberseguridad que puedan ser aplicados actualmente y puedan mitigar estos riesgos en este periodo de transición. Finalmente, en materia de robo de datos. Aunque las investigaciones preliminares realizadas en esta tesis no consiguieron realizar ningún descubrimiento significativo en el robo y venta de datos. Actualmente las darknets, en concreto la red Tor, se han convertido un punto clave en el modelo de Ransomware as a Business (RaaB), al ofrecer sitios webs de extorsión y contacto con estos grupos

    APPROXIMATE COMPUTING BASED PROCESSING OF MEA SIGNALS ON FPGA

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    The Microelectrode Array (MEA) is a collection of parallel electrodes that may measure the extracellular potential of nearby neurons. It is a crucial tool in neuroscience for researching the structure, operation, and behavior of neural networks. Using sophisticated signal processing techniques and architectural templates, the task of processing and evaluating the data streams obtained from MEAs is a computationally demanding one that needs time and parallel processing.This thesis proposes enhancing the capability of MEA signal processing systems by using approximate computing-based algorithms. These algorithms can be implemented in systems that process parallel MEA channels using the Field Programmable Gate Arrays (FPGAs). In order to develop approximate signal processing algorithms, three different types of approximate adders are investigated in various configurations. The objective is to maximize performance improvements in terms of area, power consumption, and latency associated with real-time processing while accepting lower output accuracy within certain bounds. On FPGAs, the methods are utilized to construct approximate processing systems, which are then contrasted with the precise system. Real biological signals are used to evaluate both precise and approximative systems, and the findings reveal notable improvements, especially in terms of speed and area. Processing speed enhancements reach up to 37.6%, and area enhancements reach 14.3% in some approximate system modes without sacrificing accuracy. Additional cases demonstrate how accuracy, area, and processing speed may be traded off. Using approximate computing algorithms allows for the design of real-time MEA processing systems with higher speeds and more parallel channels. The application of approximate computing algorithms to process biological signals on FPGAs in this thesis is a novel idea that has not been explored before

    Energy-Sustainable IoT Connectivity: Vision, Technological Enablers, Challenges, and Future Directions

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    Technology solutions must effectively balance economic growth, social equity, and environmental integrity to achieve a sustainable society. Notably, although the Internet of Things (IoT) paradigm constitutes a key sustainability enabler, critical issues such as the increasing maintenance operations, energy consumption, and manufacturing/disposal of IoT devices have long-term negative economic, societal, and environmental impacts and must be efficiently addressed. This calls for self-sustainable IoT ecosystems requiring minimal external resources and intervention, effectively utilizing renewable energy sources, and recycling materials whenever possible, thus encompassing energy sustainability. In this work, we focus on energy-sustainable IoT during the operation phase, although our discussions sometimes extend to other sustainability aspects and IoT lifecycle phases. Specifically, we provide a fresh look at energy-sustainable IoT and identify energy provision, transfer, and energy efficiency as the three main energy-related processes whose harmonious coexistence pushes toward realizing self-sustainable IoT systems. Their main related technologies, recent advances, challenges, and research directions are also discussed. Moreover, we overview relevant performance metrics to assess the energy-sustainability potential of a certain technique, technology, device, or network and list some target values for the next generation of wireless systems. Overall, this paper offers insights that are valuable for advancing sustainability goals for present and future generations.Comment: 25 figures, 12 tables, submitted to IEEE Open Journal of the Communications Societ

    The Use of Skeletal Muscle to Amplify Action Potentials in Transected Peripheral Nerves

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    Upper limb amputees suffer with problems associated with control and attachment of prostheses. Skin-surface electrodes placed over the stump, which detect myoelectric signals, are traditionally used to control hand movements. However, this method is unintuitive, the electrodes lift-off, and signal selectivity can be an issue. One solution to these limitations is to implant electrodes directly on muscles. Another approach is to implant electrodes directly into the nerves that innervate the muscles. A significant challenge with both solutions is the reliable transmission of biosignals across the skin barrier. In this thesis, I investigated the use of implantable muscle electrodes in an ovine model using myoelectrodes in combination with a bone-anchor, acting as a conduit for signal transmission. High-quality readings were obtained which were significantly better than skin-surface electrode readings. I further investigated the effect of electrode configurations to achieve the best signal quality. For direct recording from nerves, I tested the effect of adsorbed endoneural basement membrane proteins on nerve regeneration in vivo using microchannel neural interfaces implanted in rat sciatic nerves. Muscle and nerve signal recordings were obtained and improvements in sciatic nerve function were observed. Direct skeletal fixation of a prosthesis to the amputation stump using a bone-anchor has been proposed as a solution to skin problems associated with traditional socket-type prostheses. However, there remains a concern about the risk of infection between the implant and skin. Achieving a durable seal at this interface is therefore crucial, which formed the final part of the thesis. Bone-anchors were optimised for surface pore size and coatings to facilitate binding of human dermal fibroblasts to optimise skin-implant seal in an ovine model. Implants silanised with Arginine-Glycine-Aspartic Acid experienced significantly increased dermal tissue infiltration. This approach may therefore improve the soft tissue seal, and thus success of bone-anchored implants. By addressing both the way prostheses are attached to the amputation stump, by way of direct skeletal fixation, as well as providing high fidelity biosignals for high-level intuitive prosthetic control, I aim to further the field of limb loss rehabilitation

    System-in-package for IoT sigfox applications

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    In this work, the System-in-Package (SiP) electronic circuit manufacturing technology is presented as an economically viable alternative for implementing solutions where circuits processed in different technologies need to be integrated into a single, compact device. This technology is explored here through the development of a complete hardware plat form designed for implementing devices for the Internet of Things (IoT) in the SigFox standard. The platform consists of an RF front-end module, a sub-GHz radio transceiver capable of operating in any global SigFox configuration, and an ARM M0+ microcon troller with 64 Kbytes of Flash memory, 8 Kbytes of RAM, a 2Kbyte EEPROM, a 12-bit 1.14Msps analog-to-digital multi-channel interface, a 12-bit digital-to-analog interface, ultra-low-power comparators for implementing a wake-up system, and a complete set of digital communication peripherals. In addition to this SiP, only a power source (e.g. two AAA batteries) and an antenna are required to implement applications on the SigFox network. The system integrates an MCU, a radio transceiver, and an RF front-end module, enabling global operation of this device through Sigfox Monarch technology. The SiP operates from a supply voltage of 2.7-3.6 V, and its RF output power is programmable in the range of -30 dBm to 26 dBm. Operating at a supply voltage of 3.3V, it consumes 188.5 mA or 23 mA for RF output power of 22 dBm or 12.8 dBm, at 902.2MHz and 868.13 MHz, respectively. The device also offers a current consumption of 3 µ A in deep sleep mode. The proposed SiP design has successfully met all the requirements for Sigfox Verified certification, enabling the Sigfox Monarch function as well. Currently, it represents the solution with the smallest dimensions approved for Sigfox in the global market, measur ing only 13 mm × 13 mm × 1.1 mm.Neste trabalho é apresentada a tecnologia de fabricação de circuitos eletrônicos System in-Package (SiP), que se oferece como uma alternativa economicamente interessante para a implementação de soluções, onde circuitos processados em tecnologias diversas devem ser integrados em um único dispositivo de tamanho mínimo. Esta tecnologia é aqui explorada através do desenvolvimento de uma plataforma completa de hardware, voltada à implementação de dispositivos para a Internet das Coisas (IoT) no padrão SigFox. Esta plataforma é composta por um módulo front-end de RF, um rádio transceptor sub-GHz, capaz de operar em qualquer configuração global do padrão SigFox, além de um micro controlador ARM M0+, com 64 Kbytes de memória Flash, 8 Kbytes de memória RAM, uma EEPROM de 2Kbytes, interface multi-canal analógico-digital de 12 bits e 1.14Msps, interface digital-analógico de 12 bits, comparadores ultra-low-power para implementação de um sistema de wake-up e linha completa de periféricos de comunicação digital. Além deste SiP, é necessário apenas a conexão de uma fonte de energia (bateria ou 2 pilhas AAA) e de uma antena, para implementar aplicações ma rede SigFox. O sistema integra uma MCU, um rádio transceptor e um módulo front-end de RF, que habilita a operação global deste dispositivo através da tecnologia Sigfox Monarch. O SiP trabalha a partir de uma tensão de alimentação de 2.7-3.6 V e sua potência de saída de RF é programável na faixa de -30 dBm até 26 dBm. Operando com uma tensão de alimentação de 3.3V, ele consome 188.5 mA ou 23 mA para a potência de saída de RF de 22 dBm ou 12.8 dBm, em 902.2MHz e 868.13 MHz respectivamente. O dispositivo também oferece um consumo de corrente de 3 µA no modo deep sleep. O design de SiP proposto, atingiu todos os requisitos da certificação Sigfox Verified com sucesso, habilitando também a função Sigfox Monarch, representando atualmente a solução com as menores dimensões homologada para SigFox no mercado mundial, com apenas 13 mm × 13 mm × 1.1 mm
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