• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.5
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• pp.895-901
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• 2016

Nowadays, the axle counter has been developed to the wide range of the track circuit blocks as well as the wheel detection device. The axle counter, as becoming an important device for the high speed railway, must be guaranteed in accordance with the safety. With considering the safety and the high speed, performance evaluation a wheel detection sensor is described in this paper. To increase the safety, digital proximity sensor instead of analog is employed in the wheel detection sensor. Therefor the wheel detection sensor can minimize noisy signals caused by the harsh railway environments. And, to meet the high speed railway requirements, the performance of the wheel detection sensor is also successfully verified using the speed simulator at the velocity 500Km/h.

• Journal of the Korea Computer Graphics Society
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• v.30 no.3
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• pp.171-178
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• 2024

Exercises using a Balance Board (BB) are effective in developing balance, strengthening core muscles, and improving physical fitness and concentration. In particular, the Smart Balance Board (SBB), which integrates with various digital content, provides appropriate feedback compared to traditional balance boards, maximizing the effectiveness of the exercise. However, most systems only offer visual and auditory feedback, failing to evaluate the impact on user engagement, interest, and the accuracy of exercise postures. This study proposes an Immersive Smart Balance Board (I-SBB) that utilizes multiple sensors to enable training with various feedback mechanisms and precise postures. The proposed system, based on Arduino, consists of a gyro sensor for measuring the board's posture, a communication module for wired/wireless communication, an infrared sensor to guide the user's foot placement, and a vibration motor for tactile feedback. The board's posture measurements are smoothly corrected using a Kalman Filter, and the multi-sensor data is processed in real-time using FreeRTOS. The proposed I-SBB is shown to be effective in enhancing user concentration and engagement, as well as generating interest, by integrating with diverse content.

• Journal of rehabilitation welfare engineering & assistive technology
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• v.11 no.3
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• pp.261-270
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• 2017

Bad sitting postures are known to cause for a variety of diseases or physical deformation. However, it is not easy to fit right sitting posture for long periods of time. Therefore, methods of distinguishing and inducing good sitting posture have been constantly proposed. Proposed methods were image processing, using pressure sensor attached to the chair, and using the IMU (Internal Measurement Unit). The method of using IMU has advantages of simple hardware configuration and free of various constraints in measurement. In this paper, we researched on distinguishing sitting postures with a small amount of data using just one IMU. Feature extraction method was used to find data which contribution is the least for classification. Machine learning algorithms were used to find the best position to classify and we found best machine learning algorithm. Used feature extraction method was PCA(Principal Component Analysis). Used Machine learning models were five : SVM(Support Vector Machine), KNN(K Nearest Neighbor), K-means (K-means Algorithm) GMM (Gaussian Mixture Model), and HMM (Hidden Marcov Model). As a result of research, back neck is suitable position for classification because classification rate of it was highest in every model. It was confirmed that Yaw data which is one of the IMU data has the smallest contribution to classification rate using PCA and there was no changes in classification rate after removal it. SVM, KNN are suitable for classification because their classification rate are higher than the others.

• Proceedings of the KIEE Conference
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• 2004.11c
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• pp.660-662
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• 2004

This paper proposes an Intelligent Speed Estimator in order to realize the speed-sensorless vector control of an induction motor. Intelligent Speed Estimator used Model Reference Adaptive System which has Fuzzy-Neural adaptive mechanism as Speed Estimation method. The Intelligent Speed Estimator estimates the speed of an induction motor with a rotor flux of a reference model and adjustable model in MRAS. The Intelligent Speed Estimator reduces the error of the rotor flux between the voltage flux model and the current flux model using the error and the change of error as input of the Estimator. The computer simulation is executed to verify the propriety and the effectiveness of the proposed speed estimator.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1993.05a
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• pp.142-145
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• 1993

$TiO_2-V_2O_5$ thin films are fabricated by Sol-Gel method and humidity sensing properties have been investigated. As the results of humidity sensing properties of thin films fabricated as humidity sensor, it is confirmed to have good humidity sensing properties in high humidity and low frequency regions.

• Proceedings of the KIEE Conference
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• 2004.07d
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• pp.2304-2306
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• 2004

This paper proposes an Intelligent Speed Estimator in order to realize the speed-sensorless vector control of an induction motor. Intelligent Speed Estimator used Model Reference Adaptive System which has Fuzzy-Neural adaptive mechanism as Speed Estimation method. The Intelligent Speed Estimator estimates the speed of an induction motor with a rotor flux of a reference model and adjustable model in MRAS. The Intelligent Speed Estimator reduces the error of the rotor flux between the voltage flux model and the current flux model using the error and the change of error as input of the Estimator. The computer simulation is executed to verify the propriety and the effectiveness of the proposed speed estimator.

• Proceedings of the Acoustical Society of Korea Conference
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• spring
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• pp.383-386
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• 1999

본 연구에서는 공중용 초음파 센서에 많이 사용되고 있는 원판형 압전소자, 정합층, 그리고 후면충, 세 부분으로 이루어진 다층 접합체의 진동 특성을 기계적 진동 방정식을 이용하여 이론적으로 해석하였으며, 해석결과의 타당성을 유한요소 해석방법을 사용하여 검증하였다. 본 연구의 해석 방법은 다층 판, 특히 압전세라믹과 정합층으로 이루어진 2층과 후면층이 추가된 3층에 대한 진동 방정식에 적절한 경계 조건 및 수렴조건을 적용하여 고유진동 주파수를 유도하였다. 그리고 이를 이용하여 초음파 탐측자 개발 시 널리 사용되고 있는 설계변수 즉, 각 층의 반경, 두께, 밀도, 그리고 영률의 변화에 대한 공진주파수의 변화 경향을 분석하였다. 공진주파수 변화 경향에 대한 이 해석 방법의 타당성을 널리 사용되고 있는 유한 요소해석법을 사용하여 검증한 결과, 두 해석결과는 좋은 일치를 보였다. 그러므로 본 연구의 결과는 종래의 등가회로나 유한요소 해석법에 비해 더 간편하고, 더 정확한 해석결과를 제공할 수 있는 해석도구로써 이용될 수 있을 것이다.

• Transactions of the Korean Society of Automotive Engineers
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• v.16 no.5
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• pp.113-118
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• 2008

We have developed an integrated giant magneto resistance using not only circuit but also integrating technique with semiconductor for automobile application. It has four elements used for giant magneto resistance sensor. Ni-Fe/Cu multi layers were prepared on a glass substrate by magnetron sputtering. The dependence of magneto resistance on the thickness of the Ni-Fe and Cu layers was investigated. The MR ratio showed a saturated a peak at Cu layer $10{\AA}$, Ni-Fe layer $50{\AA}$, where the MR ratio is about 8.7% at room temperature. By means of Ni-Fe multi film and specific integrating technique, these new giant magneto resistance sensor showed excellent resistance characteristics.

• Proceedings of the Safety Management and Science Conference
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• 2011.04a
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• pp.289-295
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• 2011

본 연구는 안전체험관 특히 재난 재해 체험시설에 방문한 관람객들의 흥미유발과 적극적인 참여를 유도하기 위하여 도입되는 상호작용 체험 시스템의 설계에 대한 것이다. 설계된 안전 체험 시스템은 첫째, 관람객들에게 개별적으로 제공된 단말기의 체험관 내 위치정보와 체험 기기들의 동작감지센서정보를 기반으로 체험 여부 판단 및 체험 점수를 자동으로 산출하는 증강현실 서비스와 둘째, 체험관 내 긴급 호출 등의 안심 서비스를 제공한다. 설계된 시스템의 구현을 통하여 향후 안전테마파크 외에도 체험시설이 구비된 교통 및 과학 전시관, 체감형 게임센터 등에도 충분히 적용가능하다고 사료된다.

• Proceedings of the KIEE Conference
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• 1994.07b
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• pp.1472-1474
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• 1994

In this paper, $TiO_2-V_2O_5$ thin films are fabricated by Sol-Gel method and their humidity-sensing characteristics have been investigated. The microstructure of specimen is porous. The humidity-sensing characteristics of thin films are good according to increasing heat treatment temperature and decreasing measurement frequency.