A high-isolation eight-antenna multi-input multi-output (MIMO) array operating in the 3.5 GHz band (3.4-3.6 GHz) for future smartphones is proposed. Here, a novel balanced open-slot antenna is ...designed as an array antenna element, in which this antenna design can yield a balanced slot mode (with reduced ground effects) that can enhance the isolation between two adjacent input ports. Furthermore, by meticulously arranging the positions of the eight antenna elements, desirable polarization diversity can also be successfully achieved, which further mitigates the coupling between antenna elements. A prototype was manufactured to validate the simulation. A good impedance matching (return loss > 10 dB), high isolation (>17.5 dB), high total efficiency (>62%), and low envelope correlation coefficient (ECC, <0.05) were measured across the desired operation bandwidth. To verify the MIMO performance, ergodic channel capacity using the Kronecker channel model was calculated. The effects of hand phantom were also studied.
Indoor pedestrian tracking extends location-based services to indoor environments where GPS signal is rarely detected. Typical indoor localization method is Wi-Fi-based positioning system, which is ...practical showing accuracy and extending coverage. However, it involves significant costs of installing and managing wireless access points. A practical indoor pedestrian-tracking approach should consider the absence of any infrastructure or pretrained database. In this paper, we present a smartphone-based pedestrian dead reckoning, SmartPDR, which tracks pedestrians through typical dead reckoning approach using data from inertial sensors embedded in smartphones. SmartPDR does not require any complex and expensive additional device or infrastructure that most existing pedestrian tracking systems rely on. The proposed system was implemented on off-the-shelf smartphones and the performance was evaluated in several buildings. Despite inherent localization errors from low-cost noisy sensors and complicated human movements, SmartPDR successfully tracks indoor user's location, which is confirmed from the experimental results with reasonable location accuracy. Indoor pedestrian tracking system using smartphone inertial sensors can be a promising methodology validating its practical usage through real deployment.
Increase in workload across many organizations and consequent increase in occupational stress are negatively affecting the health of the workforce. Measuring stress and other human psychological ...dynamics is difficult due to subjective nature of selfreporting and variability between and within individuals. With the advent of smartphones, it is now possible to monitor diverse aspects of human behavior, including objectively measured behavior related to psychological state and consequently stress. We have used data from the smartphone's built-in accelerometer to detect behavior that correlates with subjects stress levels. Accelerometer sensor was chosen because it raises fewer privacy concerns (e.g., in comparison to location, video, or audio recording), and because its low-power consumption makes it suitable to be embedded in smaller wearable devices, such as fitness trackers. About 30 subjects from two different organizations were provided with smartphones. The study lasted for eight weeks and was conducted in real working environments, with no constraints whatsoever placed upon smartphone usage. The subjects reported their perceived stress levels three times during their working hours. Using combination of statistical models to classify selfreported stress levels, we achieved a maximum overall accuracy of 71% for user-specific models and an accuracy of 60% for the use of similar-users models, relying solely on data from a single accelerometer.
The pervasiveness of smartphone engagement among young adults has attracted growing interest regarding its impact on cognitive processes. However, research on the relation between smartphone use and ...executive function (EF)—a set of adaptive, goal-directed control processes—remains inconclusive due to imprecise estimation of EF dimensions and inconsistent operationalisation of smartphone use in past studies. Therefore, we examined how two indices of smartphone use—screen time and checking frequency—would predict EF (common EF, shifting-specific-, and working-memory-specific components), using a latent-variable approach based on a comprehensive battery of EF tasks. We also examined the moderating role of problematic smartphone use in the link between smartphone use and EF components. We found that screen time positively predicted working-memory-specific and shifting-specific abilities, whereas frequent checking was associated with enhanced shifting-specific, but poorer common EF, abilities. Importantly, problematic smartphone use moderated the relation between checking frequency and common EF. Overall, our findings demonstrate that different indices of smartphone use asymmetrically predict EF facets, thereby highlighting the construct distinctiveness of the various markers of smartphone engagement. Our findings imply that checking frequency and problematic use, rather than screen time, are the most promising targets for interventions that aim to circumvent cognitive impairments by curtailing smartphone use, especially in educational settings.
Over the past few decades, we have witnessed a dramatic rise in life expectancy owing to significant advances in medical science and technology, medicine as well as increased awareness about ...nutrition, education, and environmental and personal hygiene. Consequently, the elderly population in many countries are expected to rise rapidly in the coming years. A rapidly rising elderly demographics is expected to adversely affect the socioeconomic systems of many nations in terms of costs associated with their healthcare and wellbeing. In addition, diseases related to the cardiovascular system, eye, respiratory system, skin and mental health are widespread globally. However, most of these diseases can be avoided and/or properly managed through continuous monitoring. In order to enable continuous health monitoring as well as to serve growing healthcare needs; affordable, non-invasive and easy-to-use healthcare solutions are critical. The ever-increasing penetration of smartphones, coupled with embedded sensors and modern communication technologies, make it an attractive technology for enabling continuous and remote monitoring of an individual's health and wellbeing with negligible additional costs. In this paper, we present a comprehensive review of the state-of-the-art research and developments in smartphone-sensor based healthcare technologies. A discussion on regulatory policies for medical devices and their implications in smartphone-based healthcare systems is presented. Finally, some future research perspectives and concerns regarding smartphone-based healthcare systems are described.
Smartphones are programmable and equipped with a set of cheap but powerful embedded sensors, such as accelerometer, digital compass, gyroscope, GPS, microphone, and camera. These sensors can ...collectively monitor a diverse range of human activities and the surrounding environment. Crowdsensing is a new paradigm which takes advantage of the pervasive smartphones to sense, collect, and analyze data beyond the scale of what was previously possible. With the crowdsensing system, a crowdsourcer can recruit smartphone users to provide sensing service. Existing crowdsensing applications and systems lack good incentive mechanisms that can attract more user participation. To address this issue, we design incentive mechanisms for crowdsensing. We consider two system models: the crowdsourcer-centric model where the crowdsourcer provides a reward shared by participating users, and the user-centric model where users have more control over the payment they will receive. For the crowdsourcer-centric model, we design an incentive mechanism using a Stackelberg game, where the crowdsourcer is the leader while the users are the followers. We show how to compute the unique Stackelberg Equilibrium, at which the utility of the crowdsourcer is maximized, and none of the users can improve its utility by unilaterally deviating from its current strategy. For the user-centric model, we design an auction-based incentive mechanism, which is computationally efficient, individually rational, profitable, and truthful. Through extensive simulations, we evaluate the performance and validate the theoretical properties of our incentive mechanisms.
In nationally representative yearly surveys of United States 8th, 10th, and 12th graders 1991-2016 (N = 1.1 million), psychological well-being (measured by self-esteem, life satisfaction, and ...happiness) suddenly decreased after 2012. Adolescents who spent more time on electronic communication and screens (e.g., social media, the Internet, texting, gaming) and less time on nonscreen activities (e.g., in-person social interaction, sports/exercise, homework, attending religious services) had lower psychological well-being. Adolescents spending a small amount of time on electronic communication were the happiest. Psychological well-being was lower in years when adolescents spent more time on screens and higher in years when they spent more time on nonscreen activities, with changes in activities generally preceding declines in well-being. Cyclical economic indicators such as unemployment were not significantly correlated with well-being, suggesting that the Great Recession was not the cause of the decrease in psychological well-being, which may instead be at least partially due to the rapid adoption of smartphones and the subsequent shift in adolescents' time use.
This article presents a wideband orthogonal-mode dual-antenna pair with a shared radiator for fifth-generation (5G) multiple-input multiple-output (MIMO) metal-rimmed smartphones. The wideband ...decoupling property of the dual-antenna pair is realized by the combination of the orthogonal monopole/dipole modes in the lower band and the orthogonal slot/open-slot modes in the higher band. With the orthogonal-mode design scheme, the dual-antenna pair shows a wide impedance bandwidth of 3.3-5.0 GHz and a high isolation of more than 21.0 dB across the entire band without using any external decoupling structures. By arranging four such dual-antenna pairs at two side edges of the smartphone, an <inline-formula> <tex-math notation="LaTeX">8 \times 8 </tex-math></inline-formula> MIMO system is fulfilled. Both the simulation and measurement results show that the proposed <inline-formula> <tex-math notation="LaTeX">8 \times 8 </tex-math></inline-formula> MIMO system could offer an isolation of better than 12.0 dB and an envelope correlation coefficient of lower than 0.11 between all ports. The measured average antenna efficiencies are 74.7% and 57.8% for the two antenna elements of the dual-antenna pair. We portend that the proposed design scheme, with merits of shared radiator, wide bandwidth, and metal rim compatibility, has the potential for the application of future 5G smartphones.
This article provides a systematic review of existing research on problematic smartphone use (PSU) to guide other researchers in search of relevant studies, and to propose areas for future research. ...In total, 293 studies were analyzed leading to the development of an overview model in the field of PSU, presenting findings on demographic factors, explanations for smartphone use and why this use becomes problematic, consequences of PSU, and how such use can be corrected. In addition, we considered in which contexts, with which methods, and with which theoretical lenses this stream of research has been studied to date. Smartphone use is most often explained by the smartphone design, and users' emotional health and their ability to control smartphone use. Our review suggests that people who are young, female, and highly educated are more prone to PSU. Emotional health issues are the most frequently identified consequence of PSU. Strategies for correcting PSU fall into three categories: information-enhancing, capacity-enhancing, and behavior reinforcement strategies. The studies on PSU are most often conducted using quantitative surveys with university and college participants considering their personal smartphone use. Whereas a variety of theoretical frameworks have been adopted to investigate PSU, they are often related to identifying factors explaining use and problematic use, and more seldom to analyze the findings. A future research agenda for PSU is proposed consisting of seven key research questions which can be investigated by researchers going forward.
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•It is timely and important to summarize what we already know about PSU.•Research focuses on users, phone use, antecedents/consequences of PSU, and corrective measures.•The research area to date is presented including an integrated visual representation.•A future research agenda is proposed consisting of seven key research questions.
Background: In 2022, the smartphone application and pump software for the t:slim X2 with Control-IQ technology updated to allow bolus insulin programming from a user’s personal smartphone (mobile ...bolus, MB) in the United States. The aim of this study was to determine if MB increased bolus frequency in users who bolus <3 times/day.
Methods: De-identified data from users with low bolus frequency and >21 days with 70% CGM pre-and post MB were analyzed for changes in bolusing behavior and Time in Range (TIR) before and after MB.
Results: A total of 4,470 users bolused <3 times/day and upgraded to MB. After MB start, these users increased the number of boluses per day from 2.2 to 2.7 (+0.5 per day, p<0.001, table). After MB upgrade, approximately 1 bolus/day (36% of boluses) were delivered on the smartphone app instead of the insulin pump. TIR improved discreetly, with children <12 years old experiencing 34 more minutes in target range each day (p<0.01). Of all, 87% of users were very satisfied or satisfied with the MB feature.
Conclusions: For users with low bolus frequency, the MB feature meaningfully increased the number of boluses given each day, and can be leveraged as a way to increase daily bolusing behaviors.
Disclosure
L.H.Messer: Advisory Panel; Lilly, Consultant; Dexcom, Inc., Capillary Biomedical, Inc., Employee; Tandem Diabetes Care, Inc., Research Support; Beta Bionics, Inc., Medtronic, Insulet Corporation. L.Mueller: Employee; Tandem Diabetes Care, Inc., Stock/Shareholder; Tandem Diabetes Care, Inc. E.W.D'souza: None. S.Habif: Employee; Tandem Diabetes Care, Inc. J.E.Pinsker: Employee; Tandem Diabetes Care, Inc.
Funding
Tandem Diabetes Care, Inc.
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