• 센서학회지
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• 제17권1호
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• pp.81-85
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• 2008

This paper addressed real-time urine monitoring device for intensive care patients. The device was developed to detect and count each urine drop using optical sensor and calculate the current urine output volume and its hourly rate. In experiment, the water volume scale of drainage bottle was observed and compared with the count of the device so that the volume of each drop was found to vary with the dropping rate per minute. From this measurement, the relationship equation was derived to estimate the total water volume from the drop rate (correlation coefficient : r= 0.99). The developed device could be applied to count patient's urine drop successfully. Therefore, this device can be used to monitor intensive care patient's urine status in real-time.

• ETRI Journal
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• 제37권4호
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• pp.707-716
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• 2015

The purpose of a localization system is to estimate the coordinates of the geographic location of a mobile device. The accuracy of wireless localization is influenced by nonline-of-sight (NLOS) errors in wireless sensor networks. In this paper, we present an improved time of arrival (TOA)-based localization method for wireless sensor networks. TOA-based localization estimates the geographic location of a mobile device using the distances between a mobile station (MS) and three or more base stations (BSs). However, each of the NLOS errors along a distance measured from an MS (device) to a BS (device) is different because of dissimilar obstacles in the direct signal path between the two devices. To accurately estimate the geographic location of a mobile device in TOA-based localization, we propose an optimized localization method with a BS selection scheme that selects three measured distances that contain a relatively small number of NLOS errors, in this paper. Performance evaluations are presented, and the experimental results are validated through comparisons of various localization methods with the proposed method.

• 인터넷정보학회논문지
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• 제23권1호
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• pp.19-29
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• 2022

Natural user interface (NUI) is used for the natural motion interface without using a specific device or tool like a mouse, keyboards, and pens. Recently, as non-contact sensor-based interaction technologies for recognizing human motion, gestures, voice, and gaze have been actively studied, an environment has been prepared that can provide more diverse contents based on various interaction methods compared to existing methods. However, as the number of sensors device is rapidly increasing, the system using a lot of sensors can suffer from a lack of computational resources. To address this problem, we proposed a real-time multi-device control system for natural interactive platform. In the proposed system, we classified two types of devices as the HC devices such as high-end commercial sensor and the LC devices such astraditional monitoring sensor with low-cost. we adopt each device manager to control efficiently. we demonstrate a proposed system works properly with user behavior such as gestures, motions, gazes, and voices.

• 전기학회논문지
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• 제59권1호
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• pp.220-224
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• 2010

In this study, we designed a device for consecutively observing position, utilizing 3-axises acceleration sensor. This method offer to check his or her wrong position and developed could to help derived a position appliance. And, we developed a Cobb's angle value in three dimensional using 3-axises acceleration sensor. A proposed device with integrated accelerometers, which can detect postural changes in terms of curvature variation of the spine in the sagittal and coronal planes, has been developed with intention to facilitate posture training. The proposed device was evaluated with 3 normal subjects daily activities. We evaluated the performance of our designed device as calculating the correlation coefficients and mean errors between the angle measured by an electro-goniometer and that estimated by a gravity accelerometer and verified the accuracy and sensitivity. The results showed that the angle obtained from the proposed device revealed a linear characteristic at the range of $\pm60^{\circ}$(correlation coefficient 0.99, error range $\pm2^{\circ}$). We demonstrated that our device could detect the changes of the motion in upper trunk accurately. Also, our device showed good potential for treatment of the patients with scoliosis and prevention of the unbalance position during a daily life.

• 대한의용생체공학회:의공학회지
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• 제36권2호
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• pp.37-42
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• 2015

In this paper, we propose a wrist rehabilitation training device using pneumatic inflation and deflation of air cells. By alternating inflation and deflation of upper and lower air cells, the device makes the flexional and extensional movement for wrist rehabilitation. With the angular displacement sensor, it measures the flexion-extension angle of the wrist during the training and the bending angle is used for the automatic control of the device. Using the sensor output, the regression equation was obtained to measure the bending angle of the wrist from a wrist rehabilitation training device. The measurement error of the device was evaluated by comparing the measurement output with the angle from the photograph. The measurement error of wrist bending angle between the sensor and photo was $3.2^{\circ}$ in average. With additional test and improvement, the pneumatic wrist rehabilitation training device might be used for rehabilitation training.

• 융합신호처리학회논문지
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• 제22권3호
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• pp.128-133
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• 2021

최근 학생 및 사무직 종사자의 자세 불량으로 인한 척추계 질환의 발병율이 증가하고 있으며, 바른 자세 유지를 돕기 위한 다양한 연구가 수행되었다. 기존 연구에서는 의자 방석부분에 멤브레인 센서 또는 압력센서를 배치하여 무게의 편중을 보거나, 사용자를 구속하는 센서를 부착하여 체위변환을 측정하였다. 본 연구자는 선행연구에서 점착성 겔시트로 간편히 몸에 부착할 수 있으며, 사용자의 자세 및 체위 변화를 실시간으로 측정하여 출력하는 센서 디바이스를 개발하였으나 센서값의 정확성에서 한계점을 보였다. 본 연구에서는 체위변환 센서 디바이스의 성능을 개선하고, 각도변환 측정값의 정확도를 정량적으로 평가하는 연구를 수행하였으며, 오차율 2.53%의 높은 정확도를 확인하였다. 향후 연구에서는 멀티미디어 요소가 추가된 자세교정 훈련 컨텐츠를 보다 다양화하여 실제 사용자를 대상으로 하는 추가 연구가 필요한 것으로 사료된다.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2013년도 춘계학술대회
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• pp.332-335
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• 2013

최근들어 스마트폰 USB 포트에 키보드나 마우스, 스피커 등의 액세서리를 부착하는 사례가 증가하고 있다. 본 논문에서는 자외선이나 체온계 등 다양한 센서 액세서리를 스마트폰 USB에 접속할 때의 문제를 해결하는 센서 액세서리 플러그앤플레이 플랫폼을 제시한다. 센서 개발자는 표준화된 인터페이스에 부합하도록 센서 모듈을 제작하고 제공된 API를 활용 센서 디바이스 드라이버를 작성한다. 스마트폰에서 동작하는 센서 응용은 웹 형식으로 작성한다. 이렇게 작성된 디바이스 드라이버와 센서 웹을 지정된 센서 웹 서버에 저장한다. 센서 모듈을 구입한 사용자는 스마트폰 센서 플랫폼에 그 모듈을 플러그하기만 하면 디바이스 드라이버와 센서 웹이 서버로부터 자동으로 다운로드되어 플레이된다. 본 논문의 플랫폼 기술은 스마트폰 센서 액세서리의 활용을 크게 활성화시킬 것이다.

• 한국산학기술학회논문지
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• 제22권1호
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• pp.18-23
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• 2021

산업 전반에 걸쳐 자기장 센서에 대한 연구나 제품개발이 많이 진행되어져 왔다. 하지만 이런 제품의 단가를 낮추기 위해서는 초기 개발단계에서부터 자기장 필드와 자기장 센서의 특징과 최종제품의 특징들을 정확하게 이해하는 것이 중요하다. 특히, 자기장 필드는 비선형 데이터를 처리하는 계산이 복잡하여 실제로 사용하고 응용하기에는 매우 어렵기 때문에, 이렇게 측정된 자기장 센서값들을 정확하게 계산하기 위해서는 고가의 장비나 복잡한 알고리즘이 필요한 추세였다. 하지만, 본 논문에서는 기존 조이스틱의 특징을 이해한 상태에서 자기장 센서의 고유한 특성과 특징을 소개하면서, 자기장 센서를 사용하는 웨어러블 조이스틱을 개발하기에 적합하고 간단하면서도 기능을 충족하는 디자인 및 개발 방법들을 제시하였다. 특히, 기존 조이스틱의 기계적인 특징과 자기장 센서의 특성을 서로 잘 고려한 후에, 기존 조이스틱의 본질적인 문제인 기계적인 마모와 문제점들을 해결하고자 기계적 구성이나 선들이 필요없는 자기장 센서를 이용하여, 저가의 웨어러블 조이스틱 장치의 디자인 및 개발 할 수 있는 설계요소 및 방법들을 소개하였다. 본 논문의 개발결과로 실제 사용자 테스트를 수행하여, 본 논문의 장비를 처음 접하는 사용자들도 쉽게 이용하여 기존 조이스틱과 같이 정확하게 제어할 수 있음을 보였다.

• 한국정밀공학회지
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• 제28권11호
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• pp.1330-1338
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• 2011

Social activities of the elderly have been increasing as our society progresses toward an aging society. As their activities increase, so does the occurrence of falls that could lead to fractures. Falls are serious health hazards to the elderly. Therefore, development of a device that can detect fall accidents and prevent fracture is essential. In this study, we developed a portable fall detection system for the fracture prevention system of the elderly. The device is intended to detect a fall and activate a second device such as an air bag deployment system that can prevent fracture. The fall detection device contains a 3-axis acceleration sensor and two 2-axis tilt sensors. We measured acceleration and tilt angle of body during fall and activities of daily(ADL) living using the fall detection device that is attached on the subjects'. Moving mattress which is actuated by a pneumatic system was used in fall experiments and it could provide forced falls. Sensor data during fall and ADL were sent to computer and filtered with low-pass filter. The developed fall detection device was successful in detecting a fall about 0.1 second before a severe impact to occur and detecting the direction of the fall to provide enough time and information for the fracture preventive device to be activated. The fall detection device was also able to differentiate fall from ADL such as walking, sitting down, standing up, lying down, and running.

• 한국전기전자재료학회논문지
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• 제26권2호
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• pp.114-118
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• 2013

In this study, coupled mode piezoelectric devices for AE sensor application with excellent displacement and piezoelectric characteristics were simulated using ATILA FEM program, and then fabricated. Displacements and electromechanical coupling factors of the piezoelectric devices were investigated. The simulation results showed that excellent displacement and electromechanical coupling factor were obtained when the ratio of diameter/thickness was 1.0. The piezoelectric device of ${\Phi}/T$= 1.0 exhibited the optimum values of fr= 406 kHz, displacement= $6.11{\times}10^{-8}[m]$, $k_{eff}$= 0.648. The results show that the coupled vibration mode piezoelectric device is a promising candidate for the application of AE sensor piezoelectric device.