• Proceedings of the Korea Information Processing Society Conference
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• 2018.05a
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• pp.575-577
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• 2018

'대기전력(standby power)'이란 전원을 끈 상태에서 전기제품이 소비하는 전력이다. 한국전기연구원의 2011년 전국 대기전력 실측조사에 따르면 일반 가정의 경우 보통 전체 전기 사용량의 6% 이상이 대기전력으로 버려지고 있으며, 한해 약 4천2백억 원이 낭비되는 셈이라고 발표하였다. 이에 따라 본 논문에서는 'Fitbit'를 이용하여 수면 패턴을 파악하고, 사용자가 잠자는 사이에 사용하지 않는 기기의 전원을 차단할 수 있는 수면 분석 기반 스마트 멀티탭을 제안한다.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.19 no.4
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• pp.100-115
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• 2020

Recently, with the development of various sensors and communication technologies, the market for wearable devices capable of recording physical activity in connection with a smartphone is expanding. The purpose of this study is to analyze physical activity for each transportation modes in order to utilize wearable devices in the field of transportation. This study consists of three steps: data collection, basic statistical analysis, and physical activity analysis. Four adult males and females were recruited as investigators, and physical activity and route information were collected through Fitbit, a commercial wearable device. From the collected physical activity information, a percentage of heart rate reserve (%HRR) using a heart rate was derived and used for analysis. As a results, it was found that there is a statistically significant difference in heart rate for each transportation mode, and physical activity intensity is the highest when walking. In addition, the results of physical activity analysis for the case of using different routes for the same OD were presented. The results presented in this study are expected to be used as basic data for preparing public transportation activation policies and providing customized services for the future.

• Journal of Korean Neurosurgical Society
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• v.62 no.5
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• pp.561-566
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• 2019

Objective : Functional outcomes have traditionally been evaluated and compared using subjective surveys, such as visual analog scores (VAS), the Oswestry disability index (ODI), and Short Form-36 (SF-36), to assess symptoms and quality of life. However, these surveys are limited by their subjective natures and inherent bias caused by differences in patient perceptions of symptoms. The Fitbit $Charge^{(R)}$ (Fitbit Inc., San Francisco, CA, USA) provides accurate and objective measures of physical activity. The use of this device in patients after laminectomy would provide objective physical measures that define ambulatory function, activity level, and degree of recovery. Therefore, the present study was conducted to identify relationships between the number of steps taken by patients per day and VAS pain scores, prognoses, and postoperative functional outcomes. Methods : We prospectively investigated 22 consecutive patients that underwent laminectomy for spinal stenosis or a herniated lumbar disc between June 2015 and April 2016 by the same surgeon. When patients were admitted for surgery and first visited after surgery, preoperative and postoperative functional scores were recorded using VAS scores, ODI scores, and SF-36. The VAS scores and physical activities were recorded daily from postoperative day (POD) 1 to POD 7. The relationship between daily VAS scores and daily physical activities were investigated by simple correlation analysis and the relationship between mean number of steps taken and ODI scores after surgery was subjected to simple regression analysis. In addition, Wilcoxon's signed-rank test was used to investigate the significance of pre-to-postoperative differences in VAS, ODI, and SF-36 scores. Results : Pre-to-postoperative VAS (p<0.001), ODI (p<0.001), SF-36 mental composite scores (p=0.009), and SF-36 physical composite scores (p<0.001) scores were found to be significantly different. Numbers of steps taken from POD 1 to POD 7 were negatively correlated with daily VAS scores (r=-0.981, p<0.001). In addition, the mean number of steps from POD 3 to POD 7 and the decrease in ODI conducted one month after surgery were statistically significant (p=0.029). Conclusion : Wearable devices are not only being used increasingly by consumers as lifestyle devices, but are also progressively being used in the medical area. This is the first study to demonstrate the usefulness of a wearable device for checking patient physical activity and predicting pain and prognosis after laminectomy. Based on our experience, the wearable device used to provide measures of physical activity in the present study has the potential to provide objective information on pain severity and prognosis.

• Journal of Korea Entertainment Industry Association
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• v.14 no.7
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• pp.519-528
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• 2020

Purpose of this study is to analyze the changes in state anxiety, heart rate, and fall efficacy of the elderly through the handle height of walking assistant vehicle (WAV). The subjects were 32 elderlies. WAV was in the form of strollers, and it's handle height was set as 48% of a subject's total height. Also, it's height was divided into 48, 43, 38%. To measure the state anxiety, Korean State-Trait Anxiety Inventory was used and to measure the heart rate, Fitbit Charge 2 wrist heart rate monitor was used. To measure the fall efficacy, Fall Efficacy Scale-Korea was used. As the results of state anxiety and heart rate, the statistically significant increase showed continuously through the decrease of the handle height of WAV. As the results of fall efficacy, the statistically significant decrease showed continuously through the decrease of the handle height of WAV. In all of the post hoc test, the results of the state anxiety and fall efficacy showed significant difference among the each handle height of WAV and the results of the heart rate showed significant difference between the 48, 43% and 38% handle height of WAV. Thus, to decrease the state anxiety and heart rate and increase the fall efficacy of the elderly, the handle height of WAV should be properly positioned and considered to adjust to 48% of the user's total height.

• Journal of Information Science Theory and Practice
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• v.8 no.3
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• pp.47-63
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• 2020

This study focuses on users of activity tracking technologies and their related information behavior. How useful is the provided information by the trackers? Do users understand all information and explanations? We conducted a web-based survey. All in all, 631 users of a tracking device filled out the survey. From the perspective of information science, this investigation aims to analyze information needs considering different types of the provided information by activity tracking technologies. Are users satisfied by using the information on their steps, heart rates, and sleep duration? How do users assess readability about heart rate zones and sleep stages? Additionally, we investigated if users understand how to reflect on and adapt their health behavior based on the received explanations. According to the results, users mainly agree that the received information (raw data as well as - to a lesser extent - aggregated data in the form of corresponding diagrams) is useful, that the explanations are easy to understand, and that they know how to use this obtained information. This investigation enables an in-depth insight into how users are applying the self-quantifying activity and health information and which information needs are satisfied.

• Journal of Korean Biological Nursing Science
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• v.23 no.2
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• pp.151-158
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• 2021

Purpose: The purpose of this study was to investigate sleep quality in older adults in nursing home with objective data collection. Methods: Participants included 74 older adults in nursing homes in Korea aged 65 years or above. Data were collected using a wearable device (Fitbit), salivary melatonin level and Sleep Disorder Inventory (SDI). The Pearson correlation coefficient was calculated to examine whether there was any correlation between sleep-related variables such as Total Sleep Time (TST), Rapid Eye Movement (REM) sleep, shallow sleep, deep sleep, salivary melatonin level and SDI. Results: There were distortion of sleep structure, as TST comprised short REM sleep (15.93±5.47%), long shallow sleep (74.18±8.08%) and short deep sleep (9.89±5.03%). Also, salivary melatonin levels were low (15.06±7.77 pg/mL). Moreover, we found than melatonin was significantly associated with TST (r = .251, p= .044), REM sleep (r= .294, p= .020) and deep sleep (r= .391, p= .002). But there was no correlation between SDI and other sleeprelated variables. Conclusion: These findings highlight that insufficient sleep structure is associated with the salivary melatonin level among older adults in nursing home. We suggest developing programs to promote sleep quality of older adults in nursing homes.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.8
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• pp.99-105
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• 2017

With the advancement of Information and Communication Technology (ICT), the wearable-device industry is growing at a rapid pace in line with the hyper-connected society of people-to-things and things-to-things network connections. International Data Corporation (IDC), a market research institute, estimates that the wearable-device industry will grow rapidly by 2020, despite not yet attracting a popular response. This study investigates the trend of the wearable-device industry and draws implications for product and service development through user experience analysis. The subject of analysis was smart bands and the data generated from product review were collected and analyzed. As a result, user experience could extract utility, usability, aesthetics, value, and reliability, and polarity was analysed and visualized in the extracted data. The study results reveal that current wearable-devices are expensive, that users cannot receive useful information from the long-term viewpoint since the analysis of accumulated data remains focused on functional development, and that they are recognized as a fashion item or an accessory. These factors hinder the continuous usage, motivation and market spread of the product. In a future follow-up study, we will conduct a comparative study on bands and watches by analyzing the second smart watch.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.6
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• pp.4125-4130
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• 2015

This paper presents the communication performance for the radiation pattern reconfigurable antenna in the wearable device measuring bio signal (temperature, blood pressure, pulse etc.) of human body. The operational frequency is 2.4 - 2.5 GHz, which covers Bluetooth communication bandwidth. The maximum gain of the antennas is 1.96 dBi. The proposed antenna is efficiently transmitting and receiving signal by generating two opposite beam directions using two RF switches (PIN diode). Also, we investigated how radiation pattern changes according to three angles ($30^{\circ}$, $90^{\circ}$, $150^{\circ}$) of Top Loading. In this paper, we measured and compared the SNR (Signal-to-Noise Ratio) and BER (Bit Error Rate) performances of the proposed antennas in the condition between an ideal environment of anechoic chamber and smart house existing practical electromagnetic interferences (Universal Software Radio Peripheral, USRP). Throughout the comparing the results of the measurement of two cases, we found that the SNR is degraded over 5dB in average and BER is increased over ten times in maximum, therefore, it is confirmed that the error rate of receiving signal is increased. The measured results of SNR and BER value in this paper able to expect the performance degrading by the interference from the electromagnetic devices.

• Dementia and Neurocognitive Disorders
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• v.23 no.1
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• pp.22-29
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• 2024

Background and Purpose: Alzheimer's disease (AD) is a neurodegenerative disease characterized by a progressive decline in cognition and performance of daily activities. Recent studies have attempted to establish the relationship between AD and sleep. It is believed that patients with AD pathology show altered sleep characteristics years before clinical symptoms appear. This study evaluated the differences in sleep characteristics between cognitively asymptomatic patients with and without some amyloid burden. Methods: Sleep characteristics of 76 subjects aged 60 years or older who were diagnosed with subjective cognitive decline (SCD) but not mild cognitive impairment (MCI) or AD were measured using Fitbit^® Alta HR, a wristwatch-shaped wearable device. Amyloid deposition was evaluated using brain amyloid plaque load (BAPL) and global standardized uptake value ratio (SUVR) from fluorine-18 florbetaben positron emission tomography. Each component of measured sleep characteristics was analyzed for statistically significant differences between the amyloid-positive group and the amyloid-negative group. Results: Of the 76 subjects included in this study, 49 (64.5%) were female. The average age of the subjects was 70.72±6.09 years when the study started. 15 subjects were classified as amyloid-positive based on BAPL. The average global SUVR was 1.598±0.263 in the amyloid-positive group and 1.187±0.100 in the amyloid-negative group. Time spent in slow-wave sleep (SWS) was significantly lower in the amyloid-positive group (39.4±13.1 minutes) than in the amyloid-negative group (49.5±13.1 minutes) (p=0.009). Conclusions: This study showed that SWS is different between the elderly SCD population with and without amyloid positivity. How SWS affects AD pathology requires further research.