• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.21 no.3
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• pp.199-205
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• 2011

This paper proposes a framework to predict the mechanical fault of hot rolling mill system (HRMS). The optimum process of HRMS is usually identified by the rotating velocity of working roll. Therefore, observing the velocity of working roll is relevant to early know the HRMS condition. In this paper, we propose the framework which consists of two methods namely spectrum matrix which related to case-based fast Fourier transform(FFT) analysis, and three dimensional condition monitoring based on novel visualization. Validation of the proposed method has been conducted using vibration data acquired from HRMS by accelerometer sensors. The acquired data was also tested by developed software referred as hot rolling mill facility analysis module. The result is plausible and promising, and the developed software will be enhanced to be capable in prediction of remaining useful life of HRMS.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2014.04a
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• pp.540-542
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• 2014

This paper introduces main activities of ISO/TC 108/SC 3 and published standards. Two working groups (WG 1 and WG 6) have been orgnized to review and revise ISO standards, specifically related to measurement and calibration subjects of vibration and shocks. A new joint working group (JWG1) with IEC/SC 47E (Semiconductor acceleration calibration) has started to deal with calibration methods for analog and digital output MEMS accelerometers. Finally, Published ISO standards, technically super-visored by ISO/TC 108/SC 3, are listed in this paper to help readers understand their main contents.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.63 no.9
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• pp.1273-1280
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• 2014

This paper considers a GPS anti-spoofing problem. Spoofing is an intentional interference that mislead the GNSS receiver. The spoofing attack is very significant since the target receiver is not aware of being attacked from spoofing. Accelerometers can be used to detect the spoofing signal by being compared with the acceleration obtained from GPS information using Kalman filter. In this paper we propose an N by N-point average and M-point window algorithm to detect GPS spoofing by using accelerometers and GPS outputs. The performance of the proposed algorithm is analyzed using actual vehicle trajectory and spoofing trajectory generated from INS and GPS toolbox for simulation.

• Proceedings of the Korean Information Science Society Conference
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• 2008.06b
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• pp.124-129
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• 2008

독거노인의 수가 증가함에 따라 노인의 건강한 생활 패턴 유지 및 응급상황탐지 등을 위해 생활모니터링에 대한 연구가 요구되고 있다. 본 논문에서는 단순히 사물에 대한 접촉만으로 일상생활행위(ADL : activity of daily living)를 인식하기 보다는 노인의 행동과 연관이 있는 사물의 접촉을 함께 고려한 행위인 요소ADL를 인식하여 정확하게 최종 ADL를 인식할 수 있도록 한다. 또한, 행위센서로부터 인식된 물리적 행위분류는 간혹 튀는 데이터들로 인해 잘못된 결과가 나오므로, 이를 보정함으로써 인식의 정확성을 더 보장한다. 실험결과는 8개의 요소ADL에 대해 97% 이상의 인식 결과를 보이며, 이는 최종 ADL을 인식하는데 효율적으로 적용할 수 있음을 보인다.

• Proceedings of the Korea Contents Association Conference
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• 2009.05a
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• pp.70-73
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• 2009

Wii Remote is the primary controller for Nintendo's Wii console. A main feature of the Wii Remote is its motion sensing capability, which allows the user to interact with and manipulate items on screen via movement and pointing through the use of accelerometer and optical sensor technology. Another feature is its expandability through the use of Bluetooth. In this Study, use of motion sensors and Bluetooth capabilities. The user holding the remote on the screen, pointing to receive information about the values of the coordinates on the screen indicating the drawing of the implementation.

• Proceedings of the KSR Conference
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• 2003.10b
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• pp.483-488
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• 2003

Calibration and gauge factor readjustment process made for the health monitoring system installed in the railway bridges is reviewed and some findings are explained in this study: specifically, the calibrators made for this purpose are illustrated and the regression processes of the calibration on long-term displacement using water level sensor, longitudinal displacement using LVDT sensor, instantaneous displacement using LVDT sensors and accelerometer are described in details. Based on the regression results, new gauge factors are obtained from regression equation and another verification is made by performing another calibration again with new factors. From the second calibration, it was found that the suggested regression curves and their factors are appropriate and much better results are expected. Future work will be concentrated on the long-term analysis of the measurement data and on the database structures so that the assessment of the structure such as damage detection and remaining life estimation is possible.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2001.04a
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• pp.51-57
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• 2001

In order to estimate attenuation characteristics, nonparametric model is used. Evaluation of this model requires suites of average spectral amplitude data as a function of distance without adopting any assumed parametric forms. Values of Quality factor, Q were estimated for individual frequencies by matrix inversion of S wave amplitude spectra for 21 records of 8 small and intermediate earthquakes (2.7$(1/r)^{1/2}$. The best models for 1/Q values were found to be 0.000453+0.001851/f and 0.000451+0.009261/f, respectively. This results can be compared to the conventional functional form of Q=$af^{b}$ and be used to estimate source spectra and site response.

• 한국HCI학회:학술대회논문집
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• 2007.02b
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• pp.381-386
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• 2007

휴대용 게임기의 조작 인터페이스는 처음 등장한 이래로 지금까지 별다른 변화가 없었다. 이렇게 고정된 조작 인터페이스는 는 휴대용 게임기를 통한 사용자의 조작 경험을 제한시켰다. 우리는 이러한 전형적인 조작 방식에서 벗어나 보다 다채로운 상호작용을 할 수 있는 휴대용 게임기의 조작 인터페이스를 디자인했다. 사례 조사와 사용자 조사를 통해 동작 인식 인터페이스를 휴대용 게임기에 도입할 경우 발생할 수 있는 문제점으로는 크게 1. 화면의 가시성 2. 게임 요소의 동작 지각 3. 낯선 인터페이스에 대한 거부감 4. 주위의 시선이 신경 쓰임 5. 무게 등이 제시되었다. 이에 우리는 본체로부터 조작부와 화면부를 분리함으로써 이러한 문제를 해결할 수 있는 디자인을 제안했다. 사용자는 조작 장치를 본체로부터 분리하여 한 손에 들고 쥔 채 상하좌우로 움직이면, 조작 장치에 내장된 가속도 센서가 움직이는 방향과 속도를 인식, 본체의 처리 장치로 전달한다. 사용자는 나머지 한 손에 본체를 들고 화면을 보면서 게임을 사용할 수 있다. 프로토타입을 통해 사용자 시험을 실시한 결과 예상했던 문제점을 해결할 수 있는 가능성을 볼 수 있었다.

• 제어로봇시스템학회:학술대회논문집
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• 2002.10a
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• pp.52.3-52
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• 2002

Natural frequencies and mode shapes are two important modal data which specify the system. If the real system and FE model don't have the same local physical parameters, there will be a difference between modal data from real system and FE model. Because there is little difference in displacement mode shapes measured by an accelerometer, displacement modal update based on mode shapes including measurement errors may not be successful. In this research, strain mode shapes are used as modal data because the strain mode shapes measured by strain gauges are more sensitive than the displacement mode shapes with respect to the change of the parameters concerned in FE stiffness matrix...

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.942-945
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• 2003

Noise cause is dividing to fluid noise by exhaust flow of fan and vibration noise by rotational vibration of motor. Until now, measuring method has been used to measure vibration by the accelerometer, this method has been not measured for the vibration in some parts of brush and commutator because of motor construction. This research was purposed on the accurate analysis. using laser vibration analyzer, of noise cause against the difficult part in old times. By using this measured data, we would like to use for the design of silent motor.