• 한국전자파학회논문지
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• 제26권1호
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• pp.16-23
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• 2015

본 논문에서는 WCDMA2100 이동통신망을 사용하는 밴드형 wearable device에 적합한 bent 마이크로스트립 패치 안테나와 이를 적용하기 위한 RF configuration을 제안하였다. 제안된 안테나는 WCDMA2100 송수신 주파수 대역을 분리한 RF configuration을 사용하여 WCDMA 송신대역에서만 동작하도록 설계되었고, 후면의 도체(ground)로 인해 인체의 영향을 적게 받는다. 제안된 안테나는 flat 및 bent할 경우 모두 최대 이득은 5.3 dBi 이상, -6 dB 반사손실 대역폭은 20 MHz 이상을 가지고 전자파 인체 흡수율 시뮬레이션 $SAR_{1g}$ 0.7 [W/kg] 이하를 갖는다. 제안된 안테나는 사람의 손목이나 팔에 착용하는 밴드형 wearable device에 적합하게 사용될 수 있다.

• 한국전자통신학회논문지
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• 제13권1호
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• pp.153-162
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• 2018

웨어러블 디바이스의 서비스 제공을 위한 지속 가능한 전원에 대한 요구가 높아짐에 따라 에너지 하베스팅의 중요성이 증대되고 있다. 본 연구는 마찰소자를 고려한 다중 에너지 하베스팅 플랫폼인 EH-P를 개발하였다. 높은 전압과 낮은 전류를 가진 하베스팅 소자에 전압을 낮추면서 전류를 높일 수 있는 스위치 회로 제시하였다. PV와 TENG의 상호보완적 구성을 통해 실내 환경에서 짧은 시간동안 MCU가 동작할 수 있는 전압과 전류를 제공할 수 있었다. 결과적으로 제안된 플랫폼을 통해 웨어러블 플랫폼을 동작시키고, 제작된 웨어러블 디바이스에서 전체 소모 전력 요구량의 29%를 제공함으로써 웨어러블 디바이스 사용시간(device life time)을 증가시킬 수 있었다. 이 논문에 제시된 결과는 멀티플 하베스터 플랫폼에서 웨어러블 하베스팅 애플리케이션의 활용을 위한 발전 소자의 가능성을 보여주었다.

• 대한의용생체공학회:의공학회지
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• 제28권2호
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• pp.280-286
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• 2007

The wearable sensor glove was developed using EDA sensors and conducting fabric. EDA(Electro-dermal Activity) signal is an electric response of human skin. There are SIL(Skin Impedance Level) and SIR(Skin Impedance Response) in EDA. SIL consists mostly of a DC component while SIR consists of an AC component. The relationship between drowsiness and the EDA signal is utilized. EDA sensors were made using a conducting fabric instead of AgCl electrodes, for a more suitable, more wearable device. The EDA signal acquisition module was made by connecting the EDA sensor gloves through conductive fabric lines. Also, the EDA signal acquisition module can be connected to a PC that shows the results of the EDA signal processing analysis and gives proper feedback to the user. This system can be used in various applications to detect drowsiness and prevent accidents from drowsiness for automobile drivers.

• PNF and Movement
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• 제18권2호
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• pp.287-296
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• 2020

Purpose: The study aims were to develop a wearable inertial sensor-based gait analysis device that uses machine learning algorithms, and to validate this novel device using temporal gait parameters. Methods: Thirty-four healthy young participants (22 male, 12 female, aged 25.76 years) with no musculoskeletal disorders were asked to walk at three different speeds. As they walked, data were simultaneously collected by a motion capture system and inertial measurement units (Reseed®). The data were sent to a machine learning algorithm adapted to the wearable inertial sensor-based gait analysis device. The validity of the newly developed instrument was assessed by comparing it to data from the motion capture system. Results: At normal speeds, intra-class correlation coefficients (ICC) for the temporal gait parameters were excellent (ICC [2, 1], 0.99~0.99), and coefficient of variation (CV) error values were insignificant for all gait parameters (0.31~1.08%). At slow speeds, ICCs for the temporal gait parameters were excellent (ICC [2, 1], 0.98~0.99), and CV error values were very small for all gait parameters (0.33~1.24%). At the fastest speeds, ICCs for temporal gait parameters were excellent (ICC [2, 1], 0.86~0.99) but less impressive than for the other speeds. CV error values were small for all gait parameters (0.17~5.58%). Conclusion: These results confirm that both the wearable inertial sensor-based gait analysis device and the machine learning algorithms have strong concurrent validity for temporal variables. On that basis, this novel wearable device is likely to prove useful for establishing temporal gait parameters while assessing gait.

• 진공이야기
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• 제3권3호
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• pp.15-18
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• 2016

In future wearable electronic systems, 3-dimensional (3D) devices have attracted much attention due to their high density integration and low-power functionality. Among 3D devices, gate-all-around (GAA) nanowire transistor provides superior gate controllability, resulting in suppressing short channel effect and other drawbacks in 2D metal-oxide-semiconductor field-effect transistor (MOSFET). Silicon nanowires (SiNWs) are the most promising building block for GAA structure device due to their compatibility with the current Si-based ultra large scale integration (ULSI) technology. Moreover, the theoretical limit for subthreshold swing (SS) of MOSFET is 60 mV/dec at room temperature, which causes the increase in Ioff current. To overcome theoretical limit for the SS, it is crucial that research into new types of device concepts should be performed. In our present studies, we have experimentally demonstrated feedback FET (FBFET) and tunnel FET (TFET) with sub-60 mV/dec based on SiNWs. Also, we fabricated SiNW based complementary TFET (c-TFET) and SiNW complementary metal-oxide-semiconductor (CMOS) inverter. Our research demonstrates the promising potential of SiNW electronic devices for future wearable electronic systems.

• 한국전문물리치료학회지
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• 제28권4호
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• pp.251-255
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• 2021

Background: Physical activity and quality of life (QOL) influence the health status of older adults. Recently, the use of wearable devices to monitor physical activity has increased. Objects: This study examined the relationship between the amount of physical activity, measured using a wearable device, and QOL among older adults. Methods: In total, 71 older adults (aged ≥ 65 years) were enrolled. The amount of physical activity was measured using a wearable device with a wrist strap, and daily physical activity was classified according to intensity (sedentary, light, moderate, or very active). Self-reported QOL was evaluated using the Short Form 36 (SF-36) questionnaire. Pearson and Spearman correlation analyses were conducted to analyze parametric and non-parametric variables, respectively. The relationship between amount of daily physical activity and SF-36 scores was assessed. Results: The correlation analyses revealed positive correlations between the amount of moderate-intensity and very active physical activity (minutes/day) and SF-36 scores (p < 0.05). Conclusion: Physical activity of at least moderate intensity is associated with better QOL in older adults. Further studies are required to verify the effects of increased physical activity on QOL in older adults.

• Journal of Welding and Joining
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• 제32권3호
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• pp.34-42
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• 2014

Flexible devices have been developed from their rigid, heavy origins to become bendable, stretchable and portable. Such a paper displays, e-skin, textile electronics are emerging research areas and became a mainstream of overall industry. Thin film transistors, diodes and sensors built on plastic sheets, textile and other unconventional substrates have a potential applications in wearable displays, biomedical devices and electronic system. In this review, we describe current trends in technologies for flexible/wearable electronics.

• 패션비즈니스
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• 제18권4호
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• pp.1-14
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• 2014

Currently smart textile market is rapidly expanding and the demand is increasing integration of an electronic fiber circuit. The garments are an attractive platform for wearable device. This is one of the integration techniques, which consists of is the selective introduction of conductive yarns into the fabric through knitting, weaving or embroidering. The aim of this work is to develop a golf bend driven prototype design for an attachable Arduino that can be used to assess elbow motion. The process begins with the development of a wearable device technique that uses conductive yarn and flex sensor for measurement of elbow bending movements. Also this paper describes and discusses resistance value of zigzag embroidery of the conductive yarns on the tensile properties of the fabrics. Furthermore, by forming a circuit using an Arduino and flex sensor the prototype was created with an assistance band for golf posture training. This study provides valuable information to those interested in the future directions of the smart fashion industry.

• 한국멀티미디어학회논문지
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• 제19권3호
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• pp.642-649
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• 2016

This paper presents a method for conversion of muscular sense into both visual and auditory senses based on synesthetic perception. Muscular sense can be defined by rotation angles, direction changes and motion degrees of human body. Synesthetic interconversion can be made by learning, so that it can be possible to create intentional synesthetic phenomena. In this paper, the muscular sense was converted into both color and sound signals which comprise the great majority of synesthetic phenomena. The measurement of muscular sense was performed by using the AHRS(attitude heading reference system). Roll, yaw and pitch signals of the AHRS were converted into three basic elements of color as well as sound, respectively. The proposed method was finally applied to a wearable device, Samsung gear S, successfully.

• 전기학회논문지
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• 제66권12호
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• pp.1815-1820
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• 2017

In this paper, a study was conducted to estimate the maximum muscle strength which is a standard for selecting exercise intensity in weight training. We designed a device that estimates the muscle fatigue from the EMG signal, expecting to show a correlation between peak muscle strength and fatigue. Curl - Dumbbell was performed using a 4 kg dumbbell and the frequency change of the EMG was observed. At this time, the designed device acquires the signal using the MCU and finally Matlab was used to confirm the change in the center frequency value. The results of 10 subjects were analyzed using SPSS regression analysis. The statistical results showed a correlation of $R^2$ 0.583 and Significant probability of 0.010, and the relation of Y = 8.144-2.097 (slope (MDF)) was obtained. In conclusion, if the wearable device is manufactured in the form of a wearable device and the user can recommend the exercise intensity, the system will be able to retry the more efficient exercise.