Chronic obstructive pulmonary disease (COPD) is the third leading cause of death worldwide with over 3 × 10 6 deaths in 2019. Such an alarming figure becomes frightening when combined with the number of lost lives resulting from COVID-caused respiratory failure. Because COPD exacerbations identified early can commonly be treated at home, early symptom detections may enable a major reduction of COPD patient readmission and associated healthcare costs; this is particularly important during pandemics such as COVID-19 in which healthcare facilities are overwhelmed. The standard adjuncts used to assess lung function (e.g., spirometry, plethysmography, and CT scan) are expensive, time consuming, and cannot be used in remote patient monitoring of an acute exacerbation. In this paper, a wearable multi-modal system for breathing analysis is presented, which can be used in quantifying various airflow obstructions. The wearable multi-modal electroacoustic system employs a body area sensor network with each sensor-node having a multi-modal sensing capability, such as a digital stethoscope, electrocardiogram monitor, thermometer, and goniometer. The signal-to-noise ratio (SNR) of the resulting acoustic spectrum is used as a measure of breathing intensity. The results are shown from data collected from over 35 healthy subjects and 3 COPD subjects, demonstrating a positive correlation of SNR values to the health-scale score.

The current era is notably characterized by the major advances in communication technologies. The increased connectivity has been transformative in terrestrial, space, and undersea applications. Nonetheless, the water medium imposes unique constraints on the signals that can be pursued for establishing wireless links. While numerous studies have been dedicated to tackling the challenges for underwater communication, little attention has been paid to effectively interfacing the underwater networks to remote entities. Particularly it has been conventionally assumed that a surface node will be deployed to act as a relay using acoustic links for underwater nodes and radio links for air-based communication. Yet, such an assumption could be, in fact, a hindrance in practice. The paper discusses alternative means by allowing communication across the air–water interface. Specifically, the optoacoustic effect, also referred to as photoacoustic effect, is being exploited as a means for achieving connectivity between underwater and airborne nodes. The paper provides background, discusses technical challenges, and summarizes progress. Open research problems are also highlighted.

No abstract

Wireless communication from air to underwater is a longstanding challenge that can be addressed by the optoacoustic process. We can directly transmit data to underwater submerged nodes from the air with proper modulation technique by varying basic laser parameters, e.g., laser focusing angle from air to water. Laser-induced underwater plasma volume and shape are important because the duration and directivity of the generated acoustic pulses depend on these. Non-spherical shaped plasma generates anisotropic acoustic pressure; thus it is difficult to communicate from air to an unknown positioned underwater node. In this paper, we analyze how to control the shape of the plasma and propose an optical focusingbased adaptive modulation (OFAM) technique that enables transmission to underwater nodes even if the node's position is unknown. Bit error rates (BER) for different underwater node positions are analyzed, and the BER performance is compared with a lower pulse energy laser. Our results indicate that the performance is better if the underwater node position is in the direction of the laser beam, also when the laser focusing angle varies the most and a higher energy laser is used.

No abstract