• 대한통합의학회지
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• 제6권1호
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• pp.1-6
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• 2018

Purpose : The purpose of this study was to examine the effects of elastic taping on the power and velocity error of rectus femoris after muscle fatigue occurred. Method : The subjects of this study were 15 healthy students. The Primus RS was used to measure the power and velocity error of rectus femoris after muscle fatigue occurred. The power and velocity error were measured 3 times which are consist of pre-fatigue, after-fatigue and after 24 hours applied elastic tape on rectus femoris. A elastic tape was attached to rectus femoris between the antero inferior iliac spine (AIIS) and the tibia tuberosity. The collected data was analyzed using one-way repeated-measures ANOVA for comparison of the power and velocity error according to the measured time and Pearson test for correlation between the power and velocity error according to the measured time. Level of significance was set at 0.05. Result : No significant differences of the power and velocity error were found between $1^{st}$ and 2nd, 3rd measurements (p>.05). The power and velocity error, after 24 hours, of the applied elastic tape with muscle fatigue was significantly lower than muscle fatigue with no taping(p<.05). No significant correlations were found between the power and velocity error according to the measured time(p>.05). Conclusion : After applying the elastic tape on the rectus femoris, muscle fatigue occurred, which improved proprioception by decreasing movement error. It will be an important intervention to prevent musculoskeletal injuries and to enhance the motor control in exercise.

• 한국군사과학기술학회지
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• 제10권1호
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• pp.94-100
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• 2007

MVRS's measuring principles are based on the Doppler principle. It measures the velocities near the muzzle using the doppler signal output from the antenna and then predicts the velocity of the bullet leaving the muzzle by performing the regression analysis on previous measured velocities. There are a number of error sources when calculating the muzzle velocity. Antenna has long term frequency stability error and the doppler signal from the antenna has noise. These two error sources influence the accuracy of estimated velocities from the doppler signal. Estimated velocity errors result in the random error of data statistics. And when performing a regression analysis these random error components are transferred to the fitting error component. This study also analyzed the error components according to the hardware limitations of MVRS-700 and the signal processing method, and presented the calculated uncertainty of muzzle velocity.

• 제어로봇시스템학회논문지
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• 제4권1호
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• pp.56-61
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• 1998

The velocity measurement error in the velocity-aided SDINS on the maneuvering vehicle is unavoidable and degrades the performance of the SDINS. The characteristics of the velocity measurement error can be modeled as a random bias. This paper proposes a new method for estimating the velocity measurement error in the SDINS. The generalized likelihood ratio test is used for detecting the error and a modified separate-bias Kalman filter in the feedback configuration is suggested for estimating the magnitude of the velocity measurement error.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2003년도 춘계학술대회논문집
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• pp.403-407
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• 2003

This paper studies the error of pressure, particle velocity, and intensity which are distributed in a space. Errors may be amplified when other sound field variables are predicted. We theoretically derive their bias error and random error. The analysis shows that many samples do not always guarantee good results. Random error of the velocity and intensity are increased when many samples are used. The characteristics of the amplification of the random error are analyzed in terms of the sample spacing. The amplification was found to be related to the spatial differential of random noise. The numerical simulations are performed to verify theoretical results.

• 한국지능시스템학회논문지
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• 제20권6호
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• pp.814-819
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• 2010

본 논문은 자율주행 장치(autonomous ground vehicle)를 위한 각속도의 오차 최소화에 관한 연구이다. 각속도의 오차 최소화는 자율주행 장치의 이동 거리를 측정하는 엔코더(encoder)와 관련하여 자율주행 장치의 가장 중요한 기반 기술인 위치측정(localization)과 밀접한 관련이 있다. 기존에 각속도의 오차 최소화 방법들에는 이동관성을 측정할 수 있는 가속계(accelerometer)와 회전관성을 측정할 수 있는 자이로(yaw gyro), 방위각을 측정할 수 있는 자계 센서인 전자나침판(electronic compass) 센서들을 확률을 통해 상호 보완하는 형태로 활발한 연구가 이루어지고 있다. 하지만 각속도 측정을 위해 사용되는 센서들은 수학적인 오차와 센서들의 자체 특성에 의해 누적 오차가 발생하게 되며, 여러 센서들을 이용하여 확률적인 오차 보정을 수행하여도 연산량과 비용이 증가되는 문제점을 가지게 된다. 따라서 본 논문에서는 자율주행 장치의 시스템 특성을 고려하여 엔코더와 자이로만을 이용한 각속도의 오차 최소화에 대한 연구를 수행하였다. 실험은 직접 설계 제작한 자율주행 장치를 이용하였으며, 자율주행 장치가 제어기를 통해 주행하는 동안에 엔코더, 자이로를 통해 계산된 각각의 각속도 결과들과 엔코더와 자이로만을 이용한 제안된 각속도 측정 방법의 결과를 비교하였다. 실험 결과, 엔코더 혹은 자이로만을 이용한 각속도 측정 방법들에 비해 제안한 각속도 측정 방법의 누적 오차가 크게 줄었음을 확인하였다.

• 대한기계학회논문집B
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• 제32권3호
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• pp.235-240
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• 2008

The large size electromagnetic flowmeter was tested to investigate the variation of its error characteristics in the range of low velocity under 0.6 m/s using flowmeter calibration system. For the two case of valve opening rate 100 % and 50 %, these tests were undertaken three times each for twelve velocity condition from $0.05\;^m/s\;to\;0.6\;^m/s$ with increment of $0.05\;^m/s$. It is shown that error characteristic of electromagnetic flowmeter was stabilized within ${\pm}0.4%$ of rate both higher than $0.25^m/s$ of velocity condition and 50 % of valve opening position. But, measurement deviation of flowmeter for ${\Phi}400mm\;and\;{\Phi}600mm$ was out of expected deviation range. It is necessary to correction with calibration. In conclusion, error characteristic of electromagnetic flowmeter wasn't changed proportion to its size.

• 한국소음진동공학회논문집
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• 제14권4호
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• pp.352-357
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• 2004

This paper studies the errors that associated with particle velocity and intensity in a space. We theoretically derived their bias error and random error. The analysis shows that the more samples do not always guarantee the better results. The random error of the velocity and intensity are increased when we have many samples. The characteristics of the amplification of the random error are analyzed in terms of the sample spacing. The amplification was found to be related to the spatial differential of random noise. The numerical simulations are performed to verify theoretical results.

• 한국유체기계학회 논문집
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• 제12권5호
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• pp.33-38
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• 2009

In this study, the effect of flow disturbance such as contraction, expansion pipe and velocity deviation from low velocity of $0.1\;^m/s$ to $2.5\;^m/s$ on the error characteristics of the flowmeter was studied. Flow experiments using flowmeter calibration facility of K-water were undertaken for the cases of ultrasonic flowmeter based on transit-time method and electromagnetic flowmeter. Experimental results are presented that measurement error of expansion pipe are larger than contraction pipe. It is shown that the minimum straight length were required to remain of ${\pm}0.5%$ error for electromagnetic flowmeter and ${\pm}2.0%$ error for ultrasonic flowmeter.

• 제어로봇시스템학회논문지
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• 제12권8호
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• pp.739-745
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• 2006

This paper presents performance improvement of the INS velocity-adided GPS carier tracking loop. To this end, INS velocity-aided GPS carrier tracking loop was modeled as a feedfoward and a feedback loop system. In the phase tracking loop, it was shown that the tracking error caused by the dynamic motion of the vehicle can be compensated with the aiding of the INS information irrespective of the loop order and bandwidth. However, the signal trcking error increases as the INS error increases. It was also shown that in order to remove the tracking error caused by INS bias error, more than or equal to 2nd order PLL should be used. Experiments were carried out and the experimental results were compared with the analysis results.

• 한국정밀공학회지
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• 제16권12호
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• pp.14-23
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• 1999

This paper proposes a method to generate the velocity trajectory which guarantees user specified contour errors at corners for high speed and high precision motion control of CNC machines. The relation among the desired trajectory, system bandwidth and corner contour error are derived. Experiments show that the corner contour error specified by users can be guaranteed with the proposed velocity trajectory.