• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2019.05a
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• pp.281-282
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• 2019

In recent years welfare of animals is the biggest challenge because animals, especially dogs are widely recognized as pet as well as they are using as service animals. So, for the wellbeing of the dog it is necessary to perform objective assessment to track their behavior in everyday life. In this paper, we have proposed an automatic behavior assessment system for dogs based on a neck worn and tail worn accelerometer and gyroscope platform, and data analysis techniques that recognize typical dog activities. We evaluate the system based on the analysis of 8 behavior traits in 3 dogs, incorporating 2 breeds of various sizes. Our proposed framework able to reproduce the manual assessment that is based on the video recording which is treated as gold standard that exhibits the real-life use case of automated dog behavior analysis.

• Proceedings of the Korea Information Processing Society Conference
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• 2013.11a
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• pp.495-496
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• 2013

본 논문에서는 패치형 3축 가속도 센서와 스마트 디바이스를 활용하여 유산소 운동에 따라 가속도 센서를 통해 얻은 데이터의 특징을 분석하고 유산소 운동을 분류하는 모바일 시스템을 설계하였다. 제안하는 시스템을 이용하여 사용자가 하고 있는 유산소 운동을 스마트 디바이스에서 실시간으로 분류하고 분류된 운동에 따라 운동 횟수와 사용자의 움직임을 분석하여 사용자에게 편의성과 운동 정보를 제공 할 수 있다.

• Proceedings of the Korea Information Processing Society Conference
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• 2009.04a
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• pp.1336-1339
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• 2009

산업화가 진행된 세계 주요 선진국들은 의학의 발달과 평균 수명의 증가로 고령화의 위기를 겪고 있다. 인구 고령화에 따라 치매 인구도 크게 증가하였다. 치매 인구의 증가는 국가와 가정의 물질적, 인적 비용을 증가시키고 있다. 이와 같은 사회문제를 해결하고 효율적인 치매 환자 관리를 위한 방법이 필요하다. 관찰 대상자가 치매 증상과 비슷하게 행동한다면 치매를 의심해 볼 수 있다. 본 논문에서는 3축 가속도 센서를 사용하여 대상자의 행위 정보를 수집하고 디지털화한다. 디지털화 된 행위정보를 치매 증상의 행동 패턴과 비교하여 관찰 대상자의 행동이 치매 증상인지 정상적인 활동인지 판단할 수 있는 방법을 소개한다.

• Proceedings of the Korea Information Processing Society Conference
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• 2011.11a
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• pp.112-115
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• 2011

3축 가속도 센서의 활용이 점차 다양화 되면서 3차원 공간에서의 동작 인식에 대한 개발이 늘어나는 추세이다. 본 논문에서는 모바일기기의 동작을 바탕으로 한 3차원 공간에서의 동작 인식 방법을 제안한다. 동작의 인식은 3축 가속도 센서를 이용하며, 3차원 공간을 14가지 방향으로 나누어서 인식 한다. 기존의 연구에서는 3차원 가속도 데이터를 처리하여 동작을 인식하는 여러 가지 방법만을 제안했을 뿐, 3차원 공간을 방향으로 나누어 접근한 시도는 아직까지 없었다. 본 연구의 이러한 시도는 앞으로 모바일기기에서 사용자 인터페이스를 보다 쉽게 이용할 수 있는 방향으로 활용 가능할 것으로 보인다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.11
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• pp.2105-2110
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• 2008

Embedding the compact wearable units to monitor the health status of a person has been analysed as a convenient solution for the home health care. This paper presents a method to detect fall from the other activities of daily living and also to classify those activities. This kind of ambulatory monitoring of the elderly and people with limited mobility can not only provide their general health status but also alarms whenever an emergency such as fall or gait has been occurred and a help is needed. A timely assistance in such a situation can reduce the loss of life. This work shows a detailed analysis of the data received from a chest worn sensor unit embedding a 3-axis accelerometer and depicts which features are important for the classification of human activities. How to arrange and reduce the features to a new feature set so that it can be classified using a simple classifier and also improving the classification resolution. Principal component analysis (PCA) has been used for modifying the feature set and afterwards for reducing the size of the same. Finally a Neural network classifier has been used to analyse the classification accuracies. The accuracy for detection of fall events was found to be 86%. The overall accuracy for the classification of Activities or daily living (ADL) and fall was around 94%.

• Smart Structures and Systems
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• v.24 no.6
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• pp.769-781
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• 2019

Dynamic displacement response of civil structures is an important index for in-construction and in-service structural condition assessment. However, accurately measuring the displacement of large-scale civil structures such as high-rise buildings still remains as a challenging task. In order to cope with this problem, a vision-based system with the use of industrial digital camera and image processing has been developed for long-distance, remote, and real-time monitoring of dynamic displacement of supertall structures. Instead of acquiring image signals, the proposed system traces only the coordinates of the target points, therefore enabling real-time monitoring and display of displacement responses in a relatively high sampling rate. This study addresses the in-situ experimental verification of the developed vision-based system on the Canton Tower of 600 m high. To facilitate the verification, a GPS system is used to calibrate/verify the structural displacement responses measured by the vision-based system. Meanwhile, an accelerometer deployed in the vicinity of the target point also provides frequency-domain information for comparison. Special attention has been given on understanding the influence of the surrounding light on the monitoring results. For this purpose, the experimental tests are conducted in daytime and nighttime through placing the vision-based system outside the tower (in a brilliant environment) and inside the tower (in a dark environment), respectively. The results indicate that the displacement response time histories monitored by the vision-based system not only match well with those acquired by the GPS receiver, but also have higher fidelity and are less noise-corrupted. In addition, the low-order modal frequencies of the building identified with use of the data obtained from the vision-based system are all in good agreement with those obtained from the accelerometer, the GPS receiver and an elaborate finite element model. Especially, the vision-based system placed at the bottom of the enclosed elevator shaft offers better monitoring data compared with the system placed outside the tower. Based on a wavelet filtering technique, the displacement response time histories obtained by the vision-based system are easily decomposed into two parts: a quasi-static ingredient primarily resulting from temperature variation and a dynamic component mainly caused by fluctuating wind load.

• Journal of the Korea institute for structural maintenance and inspection
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• v.18 no.1
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• pp.174-182
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• 2014

To monitor the wind-induced responses of buildings, conventional real-time kinematic (RTK) methods based on two global positioning system (GPS) receivers (e.g., a reference and a rover) are widely applied. However, these methods can encounter problems such as difficulty in securing and maintaining a space for a reference station. With the recently developed virtual reference station (VRS)-RTK approach, the position of a structure can be measured using only a rover receiver. In this study, to evaluate the applicability of VRS-RTK methods in monitoring the lateral structural responses of frame structures, we performed free vibration tests on a one-story frame model (the first natural frequency of 1 Hz) and a three-story frame model (the first natural frequency of 0.85 Hz). To assess the reliability of the displacement and acceleration responses measured by the GPS, we performed a concurrent measurement using laser displacement sensors and an accelerometer. The accelerometer results were consistent with the GPS measurements in terms of the time history and frequency content. Furthermore, to derive an appropriate sampling rate for the continuous monitoring of buildings, the errors in the displacement responses were evaluated at different GPS sampling rates (5, 10, 20 Hz). The results indicate that as the sampling rate increased, the errors in the displacement responses decreased. In addition, in the three-story model, all modal components (first, second, and third modes) could be recorded at a sampling rate of 20 Hz.

• Journal of Dental Rehabilitation and Applied Science
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• v.38 no.2
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• pp.81-89
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• 2022

Purpose: Wireless endodontic handpieces (WEH) are widely used in dental clinics due to their convenience and portability. This study aimed to compare the vibration magnitudes and patterns generated by five WEH. Materials and Methods: Vibration acceleration of five WEH (X-Smart IQ, E connect S, Endo A Class, ENDOIT, and TRAUS ENDO) in the rotary and reciprocating motion was measured with accelerometer The average vibration acceleration was analyzed using the t-test, Welch's ANOVA test, and Dunnett T3 test at P < 0.05. Results: In all WEH, the average vibration acceleration in reciprocating motion was significantly higher than that in rotary motion (P < 0.001). In rotary motion, repeated vibration graphs of constant amplitude were obtained without sudden changes in the magnitude of vibration, and the average vibration acceleration value was high in the order of X Smart IQ, Endo A Class, ENDOIT, E Connect S, and TRAUS ENDO (P < 0.001), there was no statistically significant difference between X Smart IQ and Endo A Class. In reciprocating motion, a vibration graph was obtained in which large amplitude peaks appear at specific points within one cycle are repeated. The average vibration acceleration value was highest in the order of X Smart IQ, E Connect S, Endo A class, ENDOIT, and TRAUS ENDO (P < 0.001). Conclusion: Regardless of the type of WEH, greater vibration occurred in the reciprocating motion than in the rotary motion (P < 0.001). In the reciprocating motion, there was a difference in vibration for all handpieces (P < 0.001).

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.45 no.5
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• pp.21-27
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• 2008

Despite recent studies on development of pulse diagnosis systems and needs for commercializing them, the reproducibility is one of the most controversial issues as ever. Because the pulse pressure value, which is one of the important parameters to evaluate reproducibility, is very vulnerable to moving artifacts, the reproducibility can not be obtained easily. In this paper, we suggested a moving artefacts detection system for a pulse diagnosis system so that a pulse diagnosis system can be robust to theses kinds of artefacts by excluding the contaminated parts from the pulse wave signal to be analyzed. This moving artifacts detection system was designed to consist of a three-axis accelerometer, an electromyography amplifier and a two-axis tilt sensor. To assess the suitability of the system, we examined the characteristics of each sensor's output signals with regard to the three specific motions such as extension, flexion and rotation. And, we also examined the each sensor's response to the high-frequency and low-frequency moving artifacts while the pulse wave signal was acquired from a pressure sensor for the pulse diagnosis. From these results, we could find that the response to subject's motions would be reflected in electromyography signal first, in accelerometer signals and in tilt sensor sequently. And, the facts that a stable pulse wave can be acquired in two seconds after high frequency or low frequency motions ended, were also found. Consequently, based on these findings, we set up some rules on the moving artifacts detection and designed an algorithm which is fit for our moving artifacts detection system.

• KIPS Transactions on Computer and Communication Systems
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• v.6 no.11
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• pp.445-452
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• 2017

Electric pole is a supporting beam used for power transmission/distribution which accelerometer are used for measuring a external force. The meteorological condition has various effects on the external forces of electric pole. One of them is the elasticity change of the aerial wire. It is very important to perform modelling. The acceleration sensor is converted into a pitch and a roll angle. The meteorological condition has a high correlation between variables, and selecting significant explanatory variables for modeling may result in the problem of over-fitting. We constructed high deviance explained model considering multicollinearity using the Generalized Additive Model which is one of the machine learning methods. As a result of the Variation Inflation Factor Test, we selected and fitted the significant variable as temperature, precipitation, wind speed, wind direction, air pressure, dewpoint, hours of daylight and cloud cover. It was noted that the Hours of daylight, cloud cover and air pressure has high explained value in explonatory variable. The average coefficient of determination (R-Squared) of the Generalized Additive Model was 0.69. The constructed model can help to predict the influence on the external forces of electric pole, and contribute to the purpose of securing safety on utility pole.