• Proceedings of the Korea Information Processing Society Conference
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• 2016.04a
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• pp.871-874
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• 2016

본 논문은 실내 환경에서 스마트 워치(smart watch)를 이용하여 사용자의 원시 데이터를 수집, 가공하고, 이를 통해 사용자의 다양한 복합 동작을 인식하는 방법을 제안한다. 사용자의 동작을 인식하는 방법들은 다양하다. 특히 최근 웨어러블 기기(wearable device)들이 각광받으면서 웨어러블 기기를 이용하여 인체 동작이나 활동 상태 등의 생체신호를 인식하려는 다양한 시도가 일어나고 있다. 하지만 동작이나 활동 상태에 관한 많은 연구들이 센서를 허리에 부착하는 등의 특정한 상황만을 상정하거나 위성항법장치(GPS, global positioning system)에 의존한 실외 환경에 국한되어 있는데, 이는 대부분의 시간을 가정과 직장, 이동 수단 등의 실내 환경에서 소비하는 현대인들의 시간 소비 패턴과는 거리가 있다. 본 연구에서는 스마트 워치의 가속도계(accelerometer), 각속도계(gyroscope), 심박계(heart bit), 압력계(barometer) 등 다양한 센서를 통해 원시데이터를 수집, 가공하여 사용자의 앉기, 서기, 오르막이나 내리막의 걷고 뛰기, 계단의 오르내리기 등 실내에서 일어날 수 있는 복합 동작을 인식하는 방법을 제안한다.

• The Magazine of the IEIE
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• v.42 no.6
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• pp.63-70
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• 2015

• Proceedings of the Korea Contents Association Conference
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• 2015.05a
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• pp.37-38
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• 2015

최근 안드로이드 4.0 이상 버전에서 저전력 블루투스(Bluetooth Low Energy) 기능이 지원되면서, 다양한 응용사례가 나타나고 있다. 이러한 BLE 프로토콜을 활용하는 Sensor-Tag IoT 센서노드를 활용하면 스마트홈, 웨어러블, 스마트카, 생활밀착 서비스, 스마트에너지, 산업 및 환경분야에서 다양한 스마트폰 앱을 개발할 수 있다. 또한, BLE-스택(Stack)TM 소프트웨어를 사용하면, 라이센서 걱정없이 펌웨어 소스코드의 개발 및 업데이트가 가능하다. 따라서, 다양한 센서가 장착된 IoT Sensor 노드를 통하여, 습도/온도/가속도/지자기/자이로 등의 데이터를 수집하여 활용할 수 있다. 이에 본 논문에서는 "저전력 센서 노드를 사용한 IoT 서비스 설계 프레임워크"를 제안한다.

• Proceedings of the Korea Contents Association Conference
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• 2011.05a
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• pp.23-24
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• 2011

기존 성능중심의 PC에서 편의를 위한 인간 중심인 웨어러블 컴퓨터 시대로 변하고 있다. 웨어러블 컴퓨터는 제한적인 하드웨어에서 센서들과의 통신뿐만 아니라 동시에 여러 이벤트를 빠르게 처리해야 한다. SenOS는 극히 제한된 자원을 이용하면서 응용소프트웨어가 탑재된 장치가 요구하는 시간 내에 처리가 필요한 웨어러블 컴퓨터에 적합한 경량 실시간 운영체제이다. 하지만 SenOS는 현재 표준 인터페이스의 미적용으로 인해 응용프로그램의 재사용성이 낮아진다. 따라서 응용프로그램의 재사용성을 높이기 위해 표준 인터페이스를 적용할 필요성이 있다. 컴퓨팅 시스템에서 개방형 시스템 구조를 갖는 표준 중 운영체제의 인터페이스에 대한 표준으로 POSIX(Portable Operating System Interface)가 개발되어 있으며, 디지털 컨버전스 기기와 같이 실시간 운영체제 탑재를 요구하는 시스템을 위한 인터페이스 표준으로 POSIX.4 계열이 있다. 본 논문에서는 경량 실시간 운영체제 SenOS의 표준 인터페이스 적용을 위한 개방형 실시간 운영체제 인터페이스 표준인 POSIX.4 호환 계층(wrapper)을 설계 및 구현하였다.

• Composites Research
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• v.33 no.2
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• pp.50-54
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• 2020

Soft robotics and wearable devices require large motions and flexibility. In this regard, there is a demand for developing stretchable strain sensors which can be attached to the soft robots and wearable devices. In this work, we fabricated stretchable and electrically conductive composite fibers by combining polyurethane (PU) and silver nanoflowers (AgNFs). The PU/AgNF composite fibers showed the change of the resistance as a function of the applied strain, demonstrating the potential for stretchable strain sensors in soft robotics and wearable devices. The mechanical and electrical characteristics of the composite fibers were measured and analyzed to use the composite fibers for stretchable strain sensors.

• Journal of Digital Contents Society
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• v.19 no.9
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• pp.1803-1810
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• 2018

Recently, many researches related to IoT (Internet of Things) have been actively conducted. In order to improve the context aware function of smart wearable devices using the IoT, we proposed a noise reduction method for the event data of the sensor part. In thisstudy, the adoption of the low - pass filter induces the attenuation of the abnormally measured value, and the benefit was obtained from the situation recognition using the event data of the sensor. As a result, we have validated attenuation for abnormal or excessive noise using event data detected and reported by 3-axis acceleration sensors on some devices, such as smartphones and smart watches. In addition, various pattern data necessary for real - time context aware were obtained through noise pattern analysis.

• The Journal of the Korea institute of electronic communication sciences
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• v.15 no.2
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• pp.291-298
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• 2020

Sign language was designed for the deaf and dumb people to allow them to communicate with others and connect to the society. However, sign language is uncommon to the rest of the society. The unresolved communication barrier had eventually isolated deaf and dumb people from the society. Hence, this study focused on design and implementation of a wearable sign language interpreter. 6 inertial measurement unit (IMU) were placed on back of hand palm and each fingertips to capture hand and finger movements and orientations. Total of 28 proposed word-based American Sign Language were collected during the experiment, while 156 features were extracted from the collected data for classification. With the used of the long short-term memory (LSTM) algorithm, this system achieved up to 99.89% of accuracy. The high accuracy system performance indicated that this proposed system has a great potential to serve the deaf and dumb communities and resolve the communication gap.

• The Journal of the Korea institute of electronic communication sciences
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• v.18 no.2
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• pp.379-386
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• 2023

When patients suffer from finger injuries, their finger joints can become stiff and inflexible due to decreased ability to exercise the finger tendons. This can lead to a loss of strength and difficulty using their hands. To address this, it is important to provide patients with consistent rehabilitation treatment that can help restore finger flexibility and strength simultaneously. In this study, we propose wearable gloves that use FSRs (force sensitive resistors) for finger strength training. The glove is designed to be adjustable using rubber bands and a custom PCB is designed for signal acquisition. For the evaluation of finger strength training, the result was analyzed in four cases. We suggest a vector that represents the center of five finger forces, and the result shows that the vector can indicate the level of force balance.

• Science of Emotion and Sensibility
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• v.24 no.2
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• pp.65-74
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• 2021

With recent innovations in the ICT industry, the demand for wearable sensing devices to recognize and respond to biological signals has increased. In this study, a three-dimensional (3D) spacer fabric was embedded in a single-wall carbon nanotube (SWCNT) dispersive solution through a simple penetration process to develop a monolayer piezoresistive pressure sensor. To induce electrical conductivity in the 3D spacer fabric, samples were immersed in the SWCNT dispersive solution and dried. To determine the electrical properties of the impregnated specimen, a universal testing machine and multimeter were used to measure the resistance of the pressure change. Moreover, to examine the changes in the electrical properties of the sensor, its performance was evaluated by varying the concentration, number of penetrations, and thickness of the specimen. Samples that penetrated twice in the SWCNT distributed solution of 0.1 wt% showed the best performance as sensors. The 7-mm thick sensors showed the highest GF, and the 13-mm thick sensors showed the widest operating range. This study confirms the effectiveness of the simple process of fabricating smart textile sensors comprising 3D spacer fabrics and the excellent performance of the sensors.

• Science of Emotion and Sensibility
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• v.24 no.2
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• pp.49-56
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• 2021

In this study, we investigated the necessary mechanical properties of conductive multifilament yarns for fabricating the electrodes of biosignal measurement pressure and stretch textile sensors using embroidery. When electrodes and circuits for smart wearable products are produced through the embroidery process using conductive multifilament yarns, unnecessary material loss is minimized, and complex electrode shapes or circuit designs can be produced without additional processes using a computer embroidering machine. However, because ordinary missionary threads cannot overcome the stress in the embroidery process and yarn cutting occurs, herein, we analyzed the S-S curve, thickness, and twist structure, which are three types of silver-coated multifilament yarns, and measured the stress in the thread of the embroidery simultaneously. Thus, the required mechanical properties of the yarns in the embroidery process were analyzed. In the actual sample production, cutting occurred in silver-coated multifilament rather than silver-coated polyamide/polyester, which showed the lowest S-S curve. In the embroidery process, the twist was unwound through repetitive vertical movement. Further, we fabricated a piezoresistive pressure/tension sensor to measure gauge factor, which is an index for measuring biological signals. We confirmed that the sensor can be applied to the fabrication of embroidery electrodes, which is an important process in the mass production of smart wearable products.