We present a microelectromechanical system (MEMS) graphene-based pressure sensor realized by transferring a large area, few-layered graphene on a suspended silicon nitride thin membrane perforated by a periodic array of micro-through-holes. Each through-hole is covered by a circular drum-like graphene layer, namely a graphene “microdrum”. The uniqueness of the sensor design is the fact that introducing the through-hole arrays into the supporting nitride membrane allows generating an increased strain in the graphene membrane over the through-hole array by local deformations of the holes under an applied differential pressure. Further reasons contributing to the increased strain in the devised sensitive membrane include larger deflection of the membrane than that of its imperforated counterpart membrane, and direct bulging of the graphene microdrum under an applied pressure. Electromechanical measurements show a gauge factor of 4.4 for the graphene membrane and a sensitivity of 2.8 × 10⁻⁵ mbar⁻¹ for the pressure sensor with a good linearity over a wide pressure range. The present sensor outperforms most existing MEMS-based small footprint pressure sensors using graphene, silicon, and carbon nanotubes as sensitive materials, due to the high sensitivity.

This paper reports a flexible and stretchable metamaterial-based “skin” or meta-skin with tunable frequency selective and cloaking effects in microwave frequency regime. The meta-skin is composed of an array of liquid metallic split ring resonators (SRRs) embedded in a stretchable elastomer. When stretched, the meta-skin performs as a tunable frequency selective surface with a wide resonance frequency tuning range. When wrapped around a curved dielectric material, the meta-skin functions as a flexible “cloaking” surface to significantly suppress scattering from the surface of the dielectric material along different directions. We studied frequency responses of multilayer meta-skins to stretching in a planar direction and to changing the spacing between neighboring layers in vertical direction. We also investigated scattering suppression effect of the meta-skin coated on a finite-length dielectric rod in free space. This meta-skin technology will benefit many electromagnetic applications, such as frequency tuning, shielding and scattering suppression.

Background: For successful aging-in-place strategy development, in-home monitoring technology is necessary as a new home modification strategy. Monitoring an older adult’s daily physical activity at home can positively impact their health and well-being by providing valuable information about functional, cognitive, and social health status. However, it is questionable how these in-home monitoring technologies have changed the traditional residential environment. A comprehensive review of existing research findings should be utilized to characterize recent relative technologies and to inform design considerations. Objective: The main purpose of this study was to classify recent smart home technologies that monitor older adults’ health and to architecturally describe these technologies as they are used in older adults’ homes. Methods: The scoping review method was employed to identify key characteristics of in-home monitoring technologies for older adults. In June 2021, four databases, including Web of Science, IEEE Xplore, ACM Digital Library, and Scopus, were searched for peer-reviewed articles pertaining to smart home technologies used to monitor older adults’ health in their homes. We used two search strings to retrieve articles: types of technology and types of users. For the title, abstract, and full-text screening, the inclusion criteria were original and peer-reviewed research written in English, and research on monitoring, detecting, recognizing, analyzing, or tracking human physical, emotional, and social behavior. The exclusion criteria included theoretical, conceptual, or review papers; studies on wearable systems; and qualitative research. Results: This scoping review identified 30 studies published between June 2016 and 2021 providing overviews of in-home monitoring technologies, including (1) features of smart home technologies and (2) sensor locations and sensor data. First, we found six functions of in-home monitoring technology among the reviewed papers: daily activities, abnormal behaviors, cognitive impairment, falls, indoor person positioning, and sleep quality. Most of the research (n=27 articles) focused on functional monitoring and analysis, such as activities of daily living, instrumental activities of daily living, or falls among older adults; a few studies (n=3) covered social interaction monitoring. Second, this scoping review also found 16 types of sensor technologies. The most common data types encountered were passive infrared motion sensors (n=21) and contact sensors (n=19), which were used to monitor human behaviors such as bodily presence and time spent on activities. Specific locations for each sensor were also identified. Conclusions: This wide-ranging synthesis demonstrates that in-home monitoring technologies within older adults’ homes play an essential role in aging in place, in that the technology monitors older adults’ daily activities and identifies various health-related issues. This research provides a key summarization of in-home monitoring technologies that can be applied in senior housing for successful aging in place. These findings will be significant when developing home modification strategies or new senior housing.