Perspective—Maintaining the Quality of Life in Depopulating Communities: Expanding Smart Sensing via a Novel Power Supply

A growing aging population along with a declining birthrate is a societal challenge facing many industrial countries. This challenge is magni ﬁ ed in particular regional areas (e.g., remote, small communities and declining urban centers) where young people in search of better economic opportunities migrate to more modern urban centers. Advanced digital technology has the potential to partially address such challenges in a cost effective and scalable manner in helping older adults enhance their physical and mental needs by incorporating many of the advances of smart sensors into their daily lives. The an

The use of digital technologies, such as the Internet of Things (IoTs) and artificial intelligence (AI), continues to grow at an exponential pace and in conjunction with the growing generation of "big data." Depending on the market analysis, the number of IoT, which includes smart sensors, is projected to grow from the current estimates of roughly 20 billion devices for 2020 to a staggering 40-60 billion devices capable of generating nearly 80 zettabytes (ZB) of data by 2025. One of the hopes and challenges around the globe is to leverage these technologies and harness the data to transform society. For example in 2016, the Japanese government took an initial bold step by releasing a strategy and blueprint, popularly known as "Society 5.0," to create a human-centric smart society in which both economic development and the resolution of societal challenges are achieved through this digital transformation. 1 The key to its realization is the fusion of the virtual cyberspace world and the real world (physical space) to generate high-quality, secure data, and from there, to create new opportunities and solutions to resolve challenges. While Society 5.0 is Japan's economic growth strategy, its goals are not unique to Japan. The Hong Kong Special Administrative Region Government launched an ambitious HK$50 billion initiative, known as InnoHK, to develop Hong Kong as the hub for global research collaboration in the areas of AI, biotechnology, financial technologies (fintech), and smart cities. In the US, the National Science Foundation (NSF) has several major programs, including the Smart & Connected Communities (S&CC), Cyber-Physical Systems (CPS), Platforms for Advanced Wireless Research (PAWR), and Smart and Connected Health (SCH) programs, that aspire to revolutionize US cities and communities for the 21st century through enhancing economic vitality, health and wellbeing, public safety/security, and overall quality of life (QoL).
Some of the unique societal challenges facing many leading industrial nations are associated with a longer living, rapidly growing aging population an in parallel a declining birthrate. For example in Japan, this problem is quite acute with nearly 1 in 3 people over the age of 70 by 2050 with a shrinking percentage (∼10%) of working age people to provide care as compared to 2020 (Fig. 1). 2 In contrast, the percentage of the U.S. population over the age of 70 in 2050 is roughly half that of Japan; however, that is still a staggering 66 million people that is nearly an increase of 30 million additional people from 2020. The vast majority in the 70+ age groups prefer to keep their independent lifestyle as long as possible but may face the dilemma of needing some assistance to perform their daily activities. From this perspective, leveraging how other countries tackle and resolve these challenges can contribute to resolving our own pending challenges here in the US and visa versa.
While the degree of such social challenges varies from country to country, it also varies geographically within a country. In areas where there are regional employment loss or fewer employment opportunities, such as rural areas and small town communities, these regions are faced with an additional dilemma of continual migration of population away from rural areas, especially among young adults, toward urban centers. 4-6,3,7 As a result, additional strains on both human and capital resources are put on these rural/small town communities, exacerbating the societal challenges through exposing certain segments of the population (e.g., elderly, short and long-term assistance needs, etc.) to increase vulnerability and lower QoL. Although there are also numerous reports of depopulations in declining metropolitan regions (e.g., Baltimore or Buffalo), 8,9 the effects can be more pronounced in rural/small town communities as a result of being less resilient to these downward pressures and hence more challenged to benefit from this digital transformation. Ultimately, cost plays a major role and simply having a "complete makeover" of these rural/small town communities into state-of-theart smart communities is unrealistic. The prospect of leveraging smart sensors in enhancing/preserving the QoL, as well as improve social well-being, for affected individuals (a.k.a. Clients) and caregivers (e.g., professional/family) with scalable and economically modest platforms as a near term solution to these affected communities is the subject of this prospective article.

Current Status: Supplying a Novel Power Source to Smart Sensors
A critical element in any smart and connected community is powering the numerous electronic devices and smart sensors through z E-mail: larry.nagahara@jhu.edu *Electrochemical Society Fellow. **Electrochemical Society Active Member. a battery source and/or wired connection to an electrical outlet. For a large number of Clients who have declining dexterity due to age or other health related illness, the simple task of recharging an electronic device or plugging to a different outlet can be frustrating and debilitating. Another element is high-speed connectivity, which is often lacking and/or sometimes cost prohibitive for individual households in many rural communities. While clients and their caregivers living in these rural and small town communities might have resources to retrofit their home (often many decades old) and/or assisted living facilities within their communities with a WiFi network, keeping these smart devices/sensors powered is still an issue.
Wireless Power Transfer (WPT) is a growing solution that could mitigate such device power problems. Presently, WPT technologies fall into two primary categories: far-field techniques and near-field techniques. Far-field electromagnetic transmission occurs when electric power is radiated into free space (e.g., RF, microwave) and received at a distance, generally in minute quantities that are stored over time. In the case of far-field WPT techniques, concerns arise regarding low efficiencies of conversion, power consumption, and safety risk from exposure to the electromagnetic radiation [10][11][12] The health standards due to the risk of RF exposure drastically limit the amount of power that can be propagated to a device, and hence, these far-field WPT solutions will always be limited.
Near-field WPT techniques are currently the most developed and fall within two of their own categories: Inductive power transfer (IPT) and Capacitive power transfer (CPT). The most researched and commercially available of the two is IPT, with some devices (e.g., electric toothbrushes and newer smart phones) coming packaged with this recharging feature. IPT occurs when electrical power is transmitted over short distances using magnetic coupling between two coils. 13,14 IPT is typically safe, highly efficient, and has a large power transfer capacity. The other near-field category, still in the research domain, is CPT. CPT occurs when an electric field is used to transfer electric power between multiple metallic plates. 15 The voltage level in a CPT system is typically very high (500 V to 7 kV) which raises safety concerns and is the main barrier that keeps CPT from being commercially adopted. Beyond the safety concerns of Figure 1. Comparison between the U.S. and Japan population demographics for 2020 and 2050. The red line demarcates ⩾70 years old age group. 3 CPT, both IPT and CPT suffer from yet another major operational limitation that occurs when multiple devices require power at the same time, or when a single device requires power over a large area. In order to implement either technique in large scale, multi-load situations, either a large transmitter would need to be constructed that encompasses the entire area, sacrificing transfer efficiency through reduced coupling; or the entire area would need multiple imbedded transmitters. Both the wiring complexity and cost associated are not suitable as a low-cost approach for retrofitting households and/or assisted living facilities into smart communities facing attrition.
To fill the void of large area and multi-load power transfer without the use of interconnected cables, Van Neste and Thundat et al. have developed a novel capacitive technique based on singlewire no-return power transmission (SWNR). [16][17][18][19] The SWNR concept, originally developed by Nikola Tesla in the late 1800s, [20][21][22] has loads placed in various configurations along a resonant transformer, with the entire system acting as a transmission line. 23,24 Standing waves are used to reflect energy within the transmission line and efficiently suppress far-field radiation by developing a large standing wave ratio with low antenna aperture profile. The circuit is completed with stray capacitance, eliminating the need for a physical return cable. Few researchers have worked in this area, 25,26 though the research area is growing, 27,28 and subsequent demonstrations of SWNR transmission, or variations thereof, typically used high driving voltages, making power transfer to devices unsafe in the vicinity of people.
The near-field WPT technique developed by Van Neste and Thundat et al. is a low-voltage, quasi-wireless capacitive (QWiC) variation of SWNR designed to operate over surfaces. 17 The load in their system is not viewed as an external element, but as an integral part of the transmission line enabling efficient power transfer at resonance through internal dissipation. A standing wave is created in the receiving element (see Fig. 2a) whereby the nodal point occurs at the surface, enabling the potential on the surface to remain at safe, low voltage levels. Additionally, the standing wave excitation confines the energy within the system, achieving power transfer efficiencies that exceed 90% over the entire expanse of the surface.
A key piece of innovation to bringing many of the advances of smart sensors to vulnerable citizens living in rural and small town communities is the demonstration of a large area transmission over very inexpensive materials. The development of QWiC power transfer makes possible the ability to power multiple smart devices simultaneously in a cost effective and easy implementable approach. Figure 2a is a group of photographs that demonstrate lamps being QWiC powered over large conducting areas using either an inexpensive foil attached behind the furniture (such as the whiteboard), or the furniture itself in the case of the metallic cabinet. Figure 2b is a conceptual illustration of how the QWiC technology would be implemented in a room using inexpensive imbedded foils for modernizing households and/or assisted living facilities.
It is important to identify key basic metrics related to the various power sources previously discussed in order to quickly identify the advantages and disadvantages of each technology. These metrics can be classified as power transfer capacity, efficiency, size of the transmission area, installation complexity, and safety. Table I gives a quick overview of the various technology metrics based on published literature. Please note that the "safety" column in Table I is based on 100 W or less power transfer and is not representative of the safety level at the maximum transfer capacity. 100 W or less was chosen as a sufficient power level to charge multiple smart sensing devices (including small mobility vehicles). While QWiC does not presently have as large a power transfer capacity as IPT, it offers the greatest advantage in large area, multi-load power transfer making it an ideal solution for smart adaptation of aging infrastructure.

Future Needs and Prospects: Prolonging Independent Living
QWiC power transmission is one example of bringing the utility of innovative technologies to enhance and preserve QoL and social well-being for people in these rural/small town communities. Regardless of the technology, any progress and adoption going forward needs direct engagement of various community members living in these rural/small town communities rather than following the proverbial solution looking for a problem. These engagements can greatly advance the understanding to bring transformative applications with the QWiC technology and enable Clients to extend living independently (safely and successfully).
Healthcare professionals use the term, Activities of Daily Living (ADL), in referring to basic tasks an individual performs on a daily basis to maintain independence (aka self-care). The ability or inability of these ADL activities is often used as a mean of measuring a Client's functional status. Additionally, an analogous  , is tasks associated with skills and abilities connected with a relative independent lifestyle. A combination of ADL and IADL categories of activities can assess whether an individual can safely continue to reside in their own home and live independently within a community, which include some listed in Table II. By incorporating devices used for daily living with the QWiC technology, Clients could prolong their ADL and IADL activities and extend their independence. As in the case of using home telehealth in resource limited-health systems, improvement to the current healthcare delivery is evident with cost-savings to both Clients and providers. Furthermore, an added benefit for the QWiC technology is the ability to monitor multiple device usage by the Client and thereby assessing more quantitatively (e.g., longitudinally) and gaining more knowledge on their sustainability. As an example, incorporating QWiC technology into meal preparation could assist Clients. For some Clients with onset of health disabilities (e.g., Huntington's disease), performing daily tasks, like eating, can be more difficult because of unsteady hands. Electric eating utensils are available to offset hand motion that can be fitted with QWiC technology to charge the utensils more easily and monitor the level of usage. Having the charging pad placed on a countertop or refrigerator door, other kitchen utensils/devices (e.g., electric jar/bottle openers, spatula, ladle, etc.) can be easily outfitted.
Community engagement.-There are several categories of key stakeholders, besides the Client, whose input is important to having a meaningful impact for enhancing/preserving a Client's QoL. Some of these stakeholders are immediate providers, such as family members, and health/social caretakers, to the Client who might also benefit themselves when enhancing/preserving the QoL. Community organizations (e.g., social services assisted living facilities) and local government officials, who provide services on a regional and societal level, also play a vital role. As a technical community, we should also seek ways to understand how this technology can be better implemented to bring benefits beyond an individual but how it might connect to the broader community. For example, Szanton directs the Center for Innovative Care in Aging at Johns Hopkins University that provides a unique client-centric research program called, Community Aging in Place-Advancing Better Living for Elders (CAPABLE). [29][30][31][32][33] CAPABLE is a highly successful home-based intervention program for low-income older adults in the Baltimore area to increase mobility, functionality, and capacity through achieving functional Client defined goals rather than medical outcomes. In addition, there needs to be opportunities to obtain inputs/feedback from the IoT and cyberphysical system (CPS) communities around the topic of for enhancing/preserving a Client's QoL.

Summary
The convergence of digital technologies to communities where depopulation is a major issue can have profound benefits. Bringing multidisciplinary expertise around smart sensing can provide innovative solutions in powering existing and next generation digital devices to resolve such societal challenges. The need to integrate Clients and service providers with researchers and engineering is critical to finding common challenges in enhancing and preserving the QoL in our society.