A miniaturised autonomous sensor based on nanowire materials platform: the SiNAPS mote

A micro-power energy harvesting system based on core(crystalline Si)-shell(amorphous Si) nanowire solar cells together with a nanowire-modified CMOS sensing platform have been developed to be used in a dust-sized autonomous chemical sensor node. The mote (SiNAPS) is augmented by low-power electronics for power management and sensor interfacing, on a chip area of 0.25mm2. Direct charging of the target battery (e.g., NiMH microbattery) is achieved with end-to-end efficiencies up to 90% at AM1.5 illumination and 80% under 100 times reduced intensity. This requires matching the voltages of the photovoltaic module and the battery circumventing maximum power point tracking. Single solar cells show efficiencies up to 10% under AM1.5 illumination and open circuit voltages, Voc, of 450-500mV. To match the battery’s voltage the miniaturised solar cells (~1mm2 area) are connected in series via wire bonding. The chemical sensor platform (mm2 area) is set up to detect hydrogen gas concentration in the low ppm range and over a broad temperature range using a low power sensing interface circuit. Using Telran TZ1053 radio to send one sample measurement of both temperature and H2 concentration every 15 seconds, the average and active power consumption for the SiNAPS mote are less than 350nW and 2.1 μW respectively. Low-power miniaturised chemical sensors of liquid analytes through microfluidic delivery to silicon nanowires are also presented. These components demonstrate the potential of further miniaturization and application of sensor nodes beyond the typical physical sensors, and are enabled by the nanowire materials platform

An IoT fall detection and alert system for elderly persons with stroke and heart attack

Capstone Project submitted to the Department of Engineering, Ashesi University in partial fulfillment of the requirements for the award of Bachelor of Science degree in Electrical and Electronic Engineering, May 2020Abrupt falling of the aged population is a rising concern among other chronic sicknesses faced by older people in the world. Elderly patients are disposed to falling abruptly due to heart-related diseases, muscle weakness, high blood pressure, and balance-related diseases such as labyrinthitis – inflammation of the delicate balance regulating parts of the ear. This project focuses on the design and development of simple, low-cost fall detection, and smart alert system. The system detects the fall of a patient using the device's gyroscopes and accelerometers to send an alert message via mail to the caretaker for immediate intervention. The device also possesses a panic push button that can be used by the patient to call for urgent help. The device's buzzer is used to make an alert sound for caretakers who are around the patient's vicinity to respond urgently. Data collected from the device are stored in a database and further aggregated to give the patient's fall history in a web application. The web application displays the patient's fall history by showing the patient’s name, age, state, time of fall, and their condition.Ashesi Universit

Compact Antenna with Artificial Magnetic Conductor for Noninvasive Continuous Blood Glucose Monitoring

A non-invasive technique for real-time continuous monitoring of blood glucose has been under development by Venkataraman’s research group in the ETA lab at RIT [16]-[18]. The methodology involves placing an antenna on the arm and monitoring changes in the resonant frequency, which is attributed to changes in the blood glucose level. This is because the blood’s permittivity depends on the glucose levels, and in turn, affects the antenna’s resonant frequency. In order to correlate the antenna’s resonant frequency shift with the real-time blood glucose change, glucose estimation was also modeled using the antenna’s input impedance. The antennas designed could successfully track the rise and fall of blood glucose using the glucose estimation model for both diabetic and non-diabetic patients. However, the antennas being used in this research are too large in size and not flexible. Additionally, the antenna’s radiation pattern was omnidirectional as it is a monopole antenna where the radiation is into the arm as well as away from the arm (back radiation). As a result, during the test procedure, the arm must be in a steady position throughout the time of the resonant frequency measurement. While it worked very well to prove the feasibility of continuous glucose monitoring, a better antenna is required for the next phase of research that involves clinical testing in a hospital environment. My goal in this thesis is to take the research further by designing antennas that are unidirectional, flexible and small in size. The unidirectional property can be achieved by using PEC (Perfect Electric Conductors) or PMC (Perfect Magnetic Conductors) over the antenna that can suppress the back radiation. Unlike the presence of infinite electric charges on an electric conductor, magnetic charges don’t exist. Therefore magnetic conductors are modeled artificially to achieve magnetic properties commonly known as Artificial Magnetic Conductors (AMC). The antenna used in this thesis is a monopole antenna with AMC as a ground plane. The advantage of using AMC over a perfect metal conductor as a ground plane to the antenna is that the AMC reflects the incident wave in phase and not out of phase like a regular metal conductor. Moreover, AMC layers not only suppresses the back radiation but also enhances the gain of the antenna into the arm. Using the AMC layer as the ground plane has also helped in miniaturizing the antenna. The different artificial magnetic conductors designed in this thesis are Rectangular Patch, Rectangular Ring, I-shaped, and Jerusalem Cross. The antennas were fabricated and tested in the unlicensed ISM band (2.4GHz – 2.5GHz) and are within the SAR standards laid out by FCC. The fabricated antenna was strapped to the arm and measurements of resonant frequency similar to those made previously were conducted with respect to time [16]-[18]. Two types of measurements were compared, that is, when the arm was held steady and when the arm had some movement. No significant change or fluctuations in the resonant frequency was observed with arm movement. Whereas the same type of measurements conducted on the monopole antenna in [18] showed significant fluctuations in the resonant frequency with arm movement. This experiment shows the significant advantage of the antenna with AMC layer as compared to the monopole antenna. Also demonstrated in the present work, is the ability of the designed antenna in tracking the increase and decrease of glucose level with changes in the resonant frequency, similar to [16]. This has been demonstrated with two non-diabetic subjects. Further, no back radiation was noted, when a hand above the setup is moved. Additionally, the effect of creeping waves was negligible. The antenna designed in this work will conform well to clinical studies of the ETA Lab research

Single-Anchor Localization and Orientation Performance Limits Using Massive Arrays: MIMO vs. Beamforming

In the next generation of cellular networks, it is desirable to use single access points both for communication and localization. This could be made possible thanks to the combination of femtocells, mm-wave technology and massive antenna arrays, and would overcome the problem of having an over-sized infrastructure for positioning which is, nowadays, the bottleneck for the widespread diffusion of indoor localization systems. In this context, our paper aims at investigating the localization and orientation performance limits employing massive arrays both at the access point and mobile side. To this end, we first asymptotically demonstrate the tightness of the Cram\ue9r-Rao bound (CRB) in the massive array regime and that the effect of multipath can be made negligible even for practical values of SNR levels. Successively, we propose a comparison between two different transmitter configurations, namely multiple-input multiple-output (MIMO), where orthogonal waveforms are sent, and beamforming, which takes advantage of highly correlated waveforms and directive array patterns. We also consider random weighting as a trade-off between the diversity gain of MIMO and the high directivity guaranteed by the beamforming. CRB results show the interplay between diversity and beamforming gain as well as the benefits achievable by varying the number of antennas in terms of localization accuracy and multipath mitigation

Exploring outcome measures for adults with myotonic dystrophy type 1

PhD ThesisMyotonic Dystrophy type 1 (DM1) is a multisystem progressive disorder with high heterogeneity. Novel emerging therapies require assessment tools that can effectively assess the effects of an intervention. The Outcome Measures in 5 Myotonic Dystrophy (OMMYD) Consortium has proposed a battery of functional outcome measures (FOM) identified as relevant for clinical trials in DM1. However, due to the variable nature of the disease and a scarcity of resources, there is a lack of systematic research that properly explores the use of these FOM. The current study examined three of these FOM and one extra related to 10 patients’ daily life performance. These are: (1) the ten-meters walk test; (2) the ten-meters walk/run test; (3) the 30-seconds sit and stand test; and, (4) a tri-axial accelerometer. By exploring the reliability, validity and responsiveness of these outcomes, we aimed to establish reference values and standard methodologies that could serve as guidance for clinical trials in DM1. A cohort of DM1 adults 15 screened for the two largest-to-date trials in DM1 (OPTIMSITIC and PHENO-DM1) were examined in relation to a set of pre-specified assessments and disease-burden scores. The results of this thesis supply disease-specific evidence of their validity, reliability and feasibility. The FOM, have shown to be psychometrically robust measures of functionality in DM1 and to be feasible for 20 clinical trials; they can provide a picture of patients’ muscle strength and perceived mobility and participation in life. The accelerometer can objectively quantify joints accelerations when walking at different speeds and summarise a DM1 patient’s habitual physical activity. The final choice of an outcome measure for a clinical trial in DM1 should be guided by disease domain that an intervention 25 is likely to impact on; but, a disease-specific study like this one will reduce the burden of protocol design whilst providing evidence supporting the decision-making process.the Medical Research Council Centre for Neuromuscular Diseases, Consejo Nacional de Ciencia y Tecnologia of Mexico and the Barbour Foundation.

Single-Anchor Localization and Orientation Performance Limits Using Massive Arrays: MIMO vs. Beamforming

open3noIn the next generation of cellular networks, it is desirable to use single access points both for communication and localization. This could be made possible thanks to the combination of femtocells, mm-wave technology and massive antenna arrays, and would overcome the problem of having an over-sized infrastructure for positioning which is, nowadays, the bottleneck for the widespread diffusion of indoor localization systems. In this context, our paper aims at investigating the localization and orientation performance limits employing massive arrays both at the access point and mobile side. To this end, we first asymptotically demonstrate the tightness of the Cramér-Rao bound (CRB) in the massive array regime and that the effect of multipath can be made negligible even for practical values of SNR levels. Successively, we propose a comparison between two different transmitter configurations, namely multiple-input multiple-output (MIMO), where orthogonal waveforms are sent, and beamforming, which takes advantage of highly correlated waveforms and directive array patterns. We also consider random weighting as a trade-off between the diversity gain of MIMO and the high directivity guaranteed by the beamforming. CRB results show the interplay between diversity and beamforming gain as well as the benefits achievable by varying the number of antennas in terms of localization accuracy and multipath mitigation.embargoed_20181201Guerra, Anna; Guidi, Francesco; Dardari, DavideGuerra, Anna; Guidi, Francesco; Dardari, David

Ultra-low power mixed-signal frontend for wearable EEGs

Electronics circuits are ubiquitous in daily life, aided by advancements in the chip design industry, leading to miniaturised solutions for typical day to day problems. One of the critical healthcare areas helped by this advancement in technology is electroencephalography (EEG). EEG is a non-invasive method of tracking a person's brain waves, and a crucial tool in several healthcare contexts, including epilepsy and sleep disorders. Current ambulatory EEG systems still suffer from limitations that affect their usability. Furthermore, many patients admitted to emergency departments (ED) for a neurological disorder like altered mental status or seizures, would remain undiagnosed hours to days after admission, which leads to an elevated rate of death compared to other conditions. Conducting a thorough EEG monitoring in early-stage could prevent further damage to the brain and avoid high mortality. But lack of portability and ease of access results in a long wait time for the prescribed patients. All real signals are analogue in nature, including brainwaves sensed by EEG systems. For converting the EEG signal into digital for further processing, a truly wearable EEG has to have an analogue mixed-signal front-end (AFE). This research aims to define the specifications for building a custom AFE for the EEG recording and use that to review the suitability of the architectures available in the literature. Another critical task is to provide new architectures that can meet the developed specifications for EEG monitoring and can be used in epilepsy diagnosis, sleep monitoring, drowsiness detection and depression study. The thesis starts with a preview on EEG technology and available methods of brainwaves recording. It further expands to design requirements for the AFE, with a discussion about critical issues that need resolving. Three new continuous-time capacitive feedback chopped amplifier designs are proposed. A novel calibration loop for setting the accurate value for a pseudo-resistor, which is a crucial block in the proposed topology, is also discussed. This pseudoresistor calibration loop achieved the resistor variation of under 8.25%. The thesis also presents a new design of a curvature corrected bandgap, as well as a novel DDA based fourth-order Sallen-Key filter. A modified sensor frontend architecture is then proposed, along with a detailed analysis of its implementation. Measurement results of the AFE are finally presented. The AFE consumed a total power of 3.2A (including ADC, amplifier, filter, and current generation circuitry) with the overall integrated input-referred noise of 0.87V-rms in the frequency band of 0.5-50Hz. Measurement results confirmed that only the proposed AFE achieved all defined specifications for the wearable EEG system with the smallest power consumption than state-of-art architectures that meet few but not all specifications. The AFE also achieved a CMRR of 131.62dB, which is higher than any studied architectures.Open Acces

Rf sensing and processing methods for noninvasive health monitoring

Vulnerable populations include groups of people with a higher risk of poor health as a result of the limitations due to illness or disability. The health issues of vulnerable populations include three categories: physical, psychological, and social. The people with physical issues include high-risk mothers and infants, older adults and others with chronic illnesses and people with disabilities. The psychological issues of vulnerable populations include chronic mental conditions, such as bipolar disorder, major depression, and hyperactivity disorder, as well as substance abuse and those who are suicidal. The social issues in vulnerable populations include those living in abusive families, the homeless, etc. This dissertation concentrates on methods for helping two groups of vulnerable populations, namely, frail older adults and psychiatric hospital patients, to monitor their activity level, respiration rate, sleeping quality, and restless time in bed. In the first part of our work, we investigate a contactless monitoring system for psychiatric patients in a naturalistic hospital setting that can track their motion in bed, estimate the breathing rate of patients during their peaceful sleeping periods, and can be used to estimate a patient's restless time and sleep quality. Specifically, the contactless monitoring system uses a Vayyar Radar system with a carrier frequency of 6.014 GHz to capture all reflections by the FMCW (frequency modulation continuous waveform) signal. The Vayyar Radar system has been installed in a Psychiatric Center to capture 12 nights with over 135 hours of data from 7 patients. A depth camera and a thermal camera have also been installed and are used as the ground truth. The goal is to classify in bed and out of bed classes, quantify restlessness in bed, and determine the breathing rate while patients are lying in bed. We have simulated the psychiatric hospital set-up in the lab, where a respiration belt is used for ground truth, and tested the system with body postures of patients observed in the psychiatric hospital. We estimated respiration rate with different sleep postures, with the aim of investigating a contactless monitoring system for psychiatric patients in the hospital that can estimate the breathing rate of patients during typical sleeping postures, and find the torso area when the patients use other postures, such as reading books in bed or reversing the body on the bed. In the second part of our work, we investigate two methods for learning the room structure via radio wave reflections for longitudinal health monitoring of older adults in a naturalistic home setting. The goal is to use these data as part of a monitoring system that can be easily installed in a home with minimal configuration, for the purpose of detecting very early signs of illness and functional decline. Two studies are conducted using RF (radio frequency) sensing. The first method learns the structure from the RF clutter patterns and uses the beat frequency of the maximum peak in each chirp to calculate the wall position. The second method learns the room structure from active movement patterns and uses the open space between the clusters of active movement patterns to estimate the possible wall locations. Comparing the two results from these methods provides a more robust wall location. In addition, a background filter is designed based on the wall position, and the activity level of people in different rooms is estimated using a fuzzy rule system applied to the RF motion data