RESUMEN
Energy Expenditure Estimation (EEE) is vital for maintaining weight, managing chronic diseases, achieving fitness goals, and improving overall health and well-being. Gold standard measurements for energy expenditure are expensive and time-consuming, hence limiting utility and adoption. Prior work has used wearable sensors for EEE as a workaround. Moreover, earables (ear-worn sensing devices such as earbuds) have recently emerged as a sub-category of wearables with unique characteristics (i.e., small form factor, high adoption) and positioning on the human body (i.e., robust to motion, high stability, facing thin skin), opening up a novel sensing opportunity. However, earables with multimodal sensors have rarely been used for EEE, with data collected in multiple activity types. Further, it is unknown how earable sensors perform compared to standard wearable sensors worn on other body positions. In this study, using a publicly available dataset gathered from 17 participants, we evaluate the EEE performance using multimodal sensors of earable devices to show that an MAE of 0.5 MET (RMSE = 0.67) can be achieved. Furthermore, we compare the EEE performance of three commercial wearable devices with the earable, demonstrating competitive performance of earables.Clinical Relevance - This study confirms that multimodal sensors in earables could be used for EEE with comparable performance to other commercial wearables.
Asunto(s)
Dispositivos Electrónicos Vestibles , Humanos , Ejercicio Físico , Movimiento (Física) , Metabolismo Energético , PosturaRESUMEN
We demonstrate a bar code sensing system for the THz region using leaky parallel plate waveguide and an off-axis parabolic mirror. The bars of the bar code are made from metal with air as gaps between them. We use up to 6 bars in the barcode system which can store up to 64 bits. Because the system employs coherent detection, we can further increase the bit density by adding Teflon strips to the barcode, encoding information in both amplitude and phase delay. These bar codes can be manufactured easily and inexpensively, offering a versatile alternative to RFID tags.
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Terahertz technology has greatly benefited from the recent development and generalization of prototyping technologies such as 3D printing and laser machining. These techniques can be used to rapidly fabricate optical devices for applications in sensing, imaging and communications. In this paper, we introduce hot stamping, a simple inexpensive and rapid technique to form 2D metallic patterns that are suitable for many terahertz devices. We fabricate several example devices to illustrate the versatility of the technique, including metasurfaces made of arrays of split-ring resonators with resonances up to 550 GHz. We also fabricate a wire-grid polarizer for use as a polarizing beam splitter. The simplicity and low cost of this technique can help in rapid prototyping and realization of future terahertz devices.
RESUMEN
The design of antennas for terahertz systems remains a significant challenge. These antennas must provide very high gain to overcome significant free-space path loss, which limits their ability to broadcast or receive a beam over a wide angular range. To circumvent this limitation, here we describe a new device concept, based on the application of quasi-conformal transformation optics to the traditional Luneburg lens. This device offers the possibility for wide-angle beam steering and beam reception over a broad bandwidth, scalable to any frequency band in the THz range.
RESUMEN
We demonstrate a 2D radar system for the THz region using a leaky parallel-plate waveguide, which can support real-time object tracking. The system can track a target within 200â ms with an accuracy of 1â mm in range and 1.4° in angle. Because the system is based on broadband excitation, it can locate multiple objects simultaneously. The broadband excitation also enables sensing of objects for which there is no direct line-of-sight path to the waveguide, via detection of a non-line-of-sight path.
