Surface-mounted parallel-plate coupler for cylindric dielectric waveguides

Surface-mounted parallel-plate capacitors (PPCs) can be used as transducing elements in wireless communication, for example, in human-body-dedicated applications, such as healthcare monitoring or activity tracking, which require robust wireless communications and user-convenient implementation. In this context, PPCs are an attractive element due to their mobility, noninvasive positioning, and small form factors. Moreover, they are relatively easy to analyze with a simple design. This work studies the use of PPCs on dielectric, cylindrical waveguides as a precursor to the relatively complex electromagnetic environment that the human body is. The electromagnetic fields surrounding PPCs placed on a dielectric medium are described theoretically. This theory involves a combination of surface waves, inductive coupling, and quasi-static coupling between PPCs. In dielectric (cylindric) waveguides, the material's dimensions and frequency of excitation dictate whether propagation of certain modes can occur. This article shows, on one hand, that these modes can be excited by a surface-mounted waveguide coupler such as PPCs, and on the other hand, that the associated propagation is governed by modal characteristics

Sampling modulation: An energy efficient novel feature extraction for biosignal processing

Extracting useful information from human bio potentials is an essential component of many wearable health applications. Yet the feature extraction itself can be computationally demanding, and may rapidly exhaust the meager energy supply available to the sensor node. General-purpose time-frequency analysis techniques, such as the Discrete Wavelet Transform (DWT) are widely used, but are computationally demanding and may represent overkill. This work presents a feature extraction technique for biopotential time-frequency analysis, based on the modulation of finite sample differences. The technique is applied to EEG-based seizure detection (feeding a Support Vector Machine (SVM) classifier) and reaches the performance of a DWT implementation, while offering a gain of 5 7 in power efficiency and 41 7 in execution

A Comparative Study of On-Body Radio-Frequency Links in the 420 MHz-2.4 GHz Range

While there exists a wide variety of radio frequency (RF) technologies amenable for usage in Wireless Body Area Networks (WBANs), which have been studied separately before, it is currently still unclear how their performance compares in true on-body scenarios. In this paper, a single reference on-body scenario-that is, propagation along the arm-is used to experimentally compare six distinct RF technologies (between 420 MHz and 2.4 GHz) in terms of path loss. To further quantify on-body path loss, measurements for five different on-body scenarios are presented as well. To compensate for the effect of often large path losses, two mitigation strategies to (dynamically) improve on-body links are introduced and experimentally verified: beam steering using a phased array, and usage of on-body RF repeaters. The results of this study can serve as a tool for WBAN designers to aid in the selection of the right RF frequency and technology for their application.status: publishe

A Comparative Study of On-Body Radio-Frequency Links in the 420 MHz–2.4 GHz Range

While there exists a wide variety of radio frequency (RF) technologies amenable for usage in Wireless Body Area Networks (WBANs), which have been studied separately before, it is currently still unclear how their performance compares in true on-body scenarios. In this paper, a single reference on-body scenario—that is, propagation along the arm—is used to experimentally compare six distinct RF technologies (between 420 MHz and 2.4 GHz) in terms of path loss. To further quantify on-body path loss, measurements for five different on-body scenarios are presented as well. To compensate for the effect of often large path losses, two mitigation strategies to (dynamically) improve on-body links are introduced and experimentally verified: beam steering using a phased array, and usage of on-body RF repeaters. The results of this study can serve as a tool for WBAN designers to aid in the selection of the right RF frequency and technology for their application

A Comparative Study of On-Body Radio-Frequency Links in the 420 MHz⁻2.4 GHz Range.

While there exists a wide variety of radio frequency (RF) technologies amenable for usage in Wireless Body Area Networks (WBANs), which have been studied separately before, it is currently still unclear how their performance compares in true on-body scenarios. In this paper, a single reference on-body scenario-that is, propagation along the arm-is used to experimentally compare six distinct RF technologies (between 420 MHz and 2.4 GHz) in terms of path loss. To further quantify on-body path loss, measurements for five different on-body scenarios are presented as well. To compensate for the effect of often large path losses, two mitigation strategies to (dynamically) improve on-body links are introduced and experimentally verified: beam steering using a phased array, and usage of on-body RF repeaters. The results of this study can serve as a tool for WBAN designers to aid in the selection of the right RF frequency and technology for their application

The 2019 Le Teil surface-rupturing earthquake along the La Rouvière Fault within the Cévennes fault system (France): What does paleoseismology reveal?

International audienceThe 2019-11-1, Mw4.9 Le Teil earthquake occurred within the NE termination of the Cévennes faults system (CFS) in southern France, along the La Rouvière fault (LRF), an Oligocene normal fault which was not known to be potentially active. This shallow moderate magnitude reversefaulting event produced a 5 km-long surface rupture and strong ground shaking. No evidence of previous quaternary activity was observed in the morphology, raising the question whether the fault had been reactivated for the first time since the Oligocene or had broken the surface in the past without being detected in the morphology. To address this issue, we carried out paleoseismological investigations to analyze and characterize evidences of paleo-ruptures in Quaternary deposits. We discovered that at least one event prior 2019, occurred between 13.5 and 3.3 ka within the central part of the fault segment that broke in 2019, and that a possible earlier surfacerupturing event occurred within the northern part of this segment during the 16th century. Further investigations coupling sub-surface geophysical investigations and trenching are now carried out within the southern and northern segments of the LRF as well as along the other fault segments of the CFS